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  Partner: UNT Libraries
 Decade: 2010-2019
 Collection: UNT Theses and Dissertations
Measuring Atmospheric Ozone and Nitrogen Dioxide Concentration by Differential Optical Absorption Spectroscopy
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The main objective was to develop a procedure based on differential optical absorption spectroscopy (DOAS) to measure atmospheric total column of ozone, using the automated instrument developed at the University of North Texas (UNT) by Nebgen in 2006. This project also explored the ability of this instrument to provide measurements of atmospheric total column nitrogen dioxide. The instrument is located on top of UNT’s Environmental Education, Science and Technology Building. It employs a low cost spectrometer coupled with fiber optics, which are aimed at the sun to collect solar radiation. Measurements taken throughout the day with this instrument exhibited a large variability. The DOAS procedure derives total column ozone from the analysis of daily DOAS Langley plots. This plot relates the measured differential column to the airmass factor. The use of such plots is conditioned by the time the concentration of ozone remains constant. Observations of ozone are typically conducted throughout the day. Observations of total column ozone were conducted for 5 months. Values were derived from both DOAS and Nebgen’s procedure and compared to satellite data. Although differences observed from both procedures to satellite data were similar, the variability found in measurements was reduced from 70 Dobson units, with Nebgen’s procedure, to 4 Dobson units, with the DOAS procedure.A methodology to measure atmospheric nitrogen dioxide using DOAS was also investigated. Although a similar approach to ozone measurements could be applied, it was found that such measurements were limited by the amount of solar radiation collected by the instrument. Observations of nitrogen dioxide are typically conducted near sunrise or sunset, when solar radiation experiences most of the atmospheric absorption.
Measuring Male Body Dissatisfaction: Factorial and Construct Validity of the Body Parts Satisfaction Scale for Men
Given the centrality of body dissatisfaction in the manifestation of health risk behaviors (e.g., eating disorders, muscle dysmorphia) and psychological distress in men, the ability to measure it accurately is essential. Across two studies, the psychometric properties and factor structure of a new measure of male body satisfaction were established. The Body Parts Satisfaction Scale for Men (BPSS-M) was found to have three scores: full body muscularity and leanness (18 items), upper body (12 items), and legs (4 items). All three scores were internally and temporally reliable, and support was found for the convergent, discriminant, and concurrent validity of the scores. The BPSS-M represents an advance in the measurement of male body image, providing researchers and clinicians with a versatile and valid way to assess this important construct.
Measuring Semantic Relatedness Using Salient Encyclopedic Concepts
While pragmatics, through its integration of situational awareness and real world relevant knowledge, offers a high level of analysis that is suitable for real interpretation of natural dialogue, semantics, on the other end, represents a lower yet more tractable and affordable linguistic level of analysis using current technologies. Generally, the understanding of semantic meaning in literature has revolved around the famous quote ``You shall know a word by the company it keeps''. In this thesis we investigate the role of context constituents in decoding the semantic meaning of the engulfing context; specifically we probe the role of salient concepts, defined as content-bearing expressions which afford encyclopedic definitions, as a suitable source of semantic clues to an unambiguous interpretation of context. Furthermore, we integrate this world knowledge in building a new and robust unsupervised semantic model and apply it to entail semantic relatedness between textual pairs, whether they are words, sentences or paragraphs. Moreover, we explore the abstraction of semantics across languages and utilize our findings into building a novel multi-lingual semantic relatedness model exploiting information acquired from various languages. We demonstrate the effectiveness and the superiority of our mono-lingual and multi-lingual models through a comprehensive set of evaluations on specialized synthetic datasets for semantic relatedness as well as real world applications such as paraphrase detection and short answer grading. Our work represents a novel approach to integrate world-knowledge into current semantic models and a means to cross the language boundary for a better and more robust semantic relatedness representation, thus opening the door for an improved abstraction of meaning that carries the potential of ultimately imparting understanding of natural language to machines.
Measuring the Effectiveness of Transfer of Learning Constructs and Intent to Transfer in a Simulation-based Leadership Training Program
The purpose of business training programs is to improve performance, which improved performance changes leadership behaviors based on the knowledge, skills, and abilities (KSAs) learned in training. One of the most common criticisms of leadership training is the tendency to focus on teaching theory but not on applying theory into practice, that is, transfer of learning. Research usually ends at the point of identifying, describing, or measuring factors that influence transfer. Ongoing research must identify what constructs in the transfer of learning process should be effectively changed or managed. There is a gap in research on the degree to which performance improvement through KSAs learned in a simulation training program actually transfer to the work environment. Additional research is needed that examines the relationship between transfer of learning and intent to transfer, which are critical outcomes in the field of human resource management and development. The purpose of the study was to examine the relationship between intent to transfer and four constructs in the transfer of learning process during a simulation-based leadership training program. Participants completed self-report assessments that measured the relationships between intent to transfer and four constructs: ability, motivation, work environment, and learner readiness. A correlational design was administered using a population of mid-level managers in a telecommunications organization.
Measuring Vital Signs Using Smart Phones
Smart phones today have become increasingly popular with the general public for its diverse abilities like navigation, social networking, and multimedia facilities to name a few. These phones are equipped with high end processors, high resolution cameras, built-in sensors like accelerometer, orientation-sensor, light-sensor, and much more. According to comScore survey, 25.3% of US adults use smart phones in their daily lives. Motivated by the capability of smart phones and their extensive usage, I focused on utilizing them for bio-medical applications. In this thesis, I present a new application for a smart phone to quantify the vital signs such as heart rate, respiratory rate and blood pressure with the help of its built-in sensors. Using the camera and a microphone, I have shown how the blood pressure and heart rate can be determined for a subject. People sometimes encounter minor situations like fainting or fatal accidents like car crash at unexpected times and places. It would be useful to have a device which can measure all vital signs in such an event. The second part of this thesis demonstrates a new mode of communication for next generation 9-1-1 calls. In this new architecture, the call-taker will be able to control the multimedia elements in the phone from a remote location. This would help the call-taker or first responder to have a better control over the situation. Transmission of the vital signs measured using the smart phone can be a life saver in critical situations. In today's voice oriented 9-1-1 calls, the dispatcher first collects critical information (e.g., location, call-back number) from caller, and assesses the situation. Meanwhile, the dispatchers constantly face a "60-second dilemma"; i.e., within 60 seconds, they need to make a complicated but important decision, whether to dispatch and, if so, what to dispatch. The dispatchers often feel that they lack sufficient information to make a confident dispatch decision. This remote-media-control described in this system will be able to facilitate information acquisition and decision-making in emergency situations within the 60-second response window in 9-1-1 calls using new multimedia technologies.
Mechanical Characterization of A2 and D2 Tool Steels By Nanoindentation
Nanoindentation technique was used to investigate the surface properties of A2 and D2 tool steel subjected to different heat treatments. the mechanical characteristics of these two easily available tool steels were studied based on microstructural images obtained from SEM, the grain growth after heat treatment using X-ray diffraction method and nanoindentation technique. the investigation showed that a single nanoindentation result can explain how heat treatment influences reliability and failure in A2 and D2 tool steels. in this work, the causes and effects of these variations were studied to explain how they influence reliability and failure in A2 and D2 tool steel. Finally, a cube-corner indenter tip was used to determine the fracture toughness of silicon wafer. the emphasis of this research is on how nanoindentation technique is more extensive in material characterization.
Mechanics and Mechanisms of Creep and Ductile Fracture
The main aim of this dissertation is to relate measurable and hopefully controllable features of a material's microstructure to its observed failure modes to provide a basis for designing better materials. The understanding of creep in materials used at high temperatures is of prime engineering importance. Single crystal Ni-based superalloys used in turbine aerofoils of jet engines are exposed to long dwell times at very high temperatures. In contrast to current theories, creep tests on Ni-based superalloy specimens have shown size dependent creep response termed as the thickness debit effect. To investigate the mechanism of the thickness debit effect, isothermal creep tests were performed on uncoated Ni-based single crystal superalloy sheet specimens with two thicknesses and under two test conditions: a low temperature high stress condition and a high temperature low stress condition. At the high temperature, surface oxidation induced microstructural changes near the free surface forming a layered microstructure. Finite element calculations showed that this layered microstructure gave rise to local changes in the stress state. The specimens also contained nonuniform distribution of initial voids formed during the solidification and homogenization processes. The experiments showed that porosity evolution could play a significant role in the thickness debit effect. This motivated a basic mechanics study of porosity evolution in single crystals subjected to creep for a range of stress states. The study was performed using three-dimensional finite deformation finite element analysis of unit cells containing a single initially spherical void in a single crystal matrix. The materials are characterized by a rate-dependent crystal plasticity constitutive relation accounting for both primary and secondary creep. The effect of initial void spacing and creep exponent was also explored. Based on the experimental observations and results of finite element calculations a quantitative mechanistic model is proposed that can account for both bulk and surface damage effects and assess their relative roles in the observed thickness debit effect. Another set of calculations aim at relating the crack growth resistance and fracture surface morphology to material microstructure for ductile structural metals. The process that governs the ductile fracture of structural materials at room temperature is one of nucleation, growth and coalescence of micron scale voids, and involves large plastic deformations. Experimental studies have shown that fracture surfaces in a wide variety of materials and under a wide variety of loading conditions have remarkable scaling properties. For thirty years, the hope to relate the statistical characterization of fracture surfaces to a measure of a material's crack growth resistance has remained unfulfilled. Only recently has the capability been developed to calculate sufficient amounts of three dimensional ductile crack growth in heterogeneous microstructures to obtain a statistical characterization of the predicted fracture surfaces. This development has enabled the exploration of the relation of both fracture toughness and fracture surface statistics to material properties and microstructure when the fracture mechanism is one of void nucleation, growth and coalescence. The relation of both toughness and the statistical properties of fracture surfaces in calculations of heterogeneous microstructures to various microstructural features is discussed and a remarkable correlation between fracture surface roughness and fracture toughness is shown for the first time.
Mechanisms Affecting Bench Press Throw Performance while Using a Counter-Balanced Smith Machine
The use of a counter-balance weight system of a Smith machine affects measures of bench press throw performance. Twenty-four men performed bench press throws at 30% of their one-repetition maximum under four different conditions: 1) counter-balance and rebound movement (RC), 2) no counter-balance and rebound movement (RNC), 3) counter-balance and concentric only movement (CC), and 4) no counter-balance and concentric only movement (CNC). Peak power, force, and concentric and eccentric velocities were measured using a linear accelerometer; and peak ground reaction force (GRF) was measured using a forceplate. Peak measures for concentric and eccentric velocities showed that NCB> CB and RBT > CBT. Peak GRF measures showed CB > NCB and RBT > CBT. The lower performance measures for CB were likely due to an increase in the net external load when the barbell accelerates faster than the gravitational constant causing the counter-balance weight becomes ineffective.
Mechanisms of Ordered Gamma Prime Precipitation in Nickel Base Superalloys
Commercial superalloys like Rene88DT are used in high temperature applications like turbine disk in aircraft jet engines due to their excellent high temperature properties, including strength, ductility, improved fracture toughness, fatigue resistance, enhanced creep and oxidation resistance. Typically this alloy's microstructure has L12-ordered precipitates dispersed in disordered face-centered cubic γ matrix. A typical industrially relevant heat-treatment often leads to the formation of multiple size ranges of γ¢ precipitates presumably arising from multiple nucleation bursts during the continuous cooling process. The morphology and distribution of these γ′ precipitates inside γ matrix influences the mechanical properties of these materials. Therefore, the study of thermodynamic and kinetic factors influencing the evolution of these precipitates and subsequent effects is both relevant for commercial applications as well as for a fundamental understanding of the underlying phase transformations. The present research is primarily focused on understanding the mechanism of formation of different generations of γ′ precipitates during continuous cooling by coupling scanning electron microscopy (SEM), energy filtered TEM and atom probe tomography (APT). In addition, the phase transformations leading to nucleation of γ′ phase has been a topic of controversy for decades. The present work, for the first time, gives a novel insight into the mechanism of order-disorder transformations and associated phase separation processes at atomistic length scales, by coupling high angle annular dark field (HAADF) - STEM imaging and APT. The results indicate that multiple competing mechanisms can operate during a single continuous cooling process leading to different generations of γ′ including a non-classical mechanism, operative at large undercoolings.
Media and Corporate Social Responsibility: How Leading Business Magazines Frame a Controversial Concept
Corporate social responsibility (CSR) is an emerging concept that continues to play a controversial role in the business world. Different CSR theories and ethical foundations inform different approaches to embedding socially responsible behavior into today's business functions. As technology, globalization, and economic challenges change the corporate world, the meaning and application of CSR also changes. While no empirical evidence of CSR's impact on performance exists, many corporations operate under the assumption that CSR holds significant value. This study examines the framing of CSR in stories published by leading business magazines between 2008 and 2012. By examining the presentation of CSR concepts, the resulting analysis can provide important conclusions for corporations, public relations practitioners, mass media, and consumers. This study resulted in a hierarchical pyramid of frames that organizes the framing of CSR in business magazines into three layers: category, motivation, and classification as either responsible behavior or irresponsible behavior. These results lead to recommendations for future CSR research, including the need for quantitative evidence of a connection or disconnection between CSR and profitability.
Medical School Admissions Across Socioeconomic Groups: An Analysis Across Race Neutral and Race Sensitive Admissions Cycles
While the relationship between academic variables and admission into medical school has been well documented, the relationship between socioeconomic background and admission has not been extensively examined. In 2001, the Texas Legislature passed HB 1641, which allowed for the use of socioeconomic variables in the admission of graduate and professional school students. Additionally, the Grutter v. Bollinger decision in 2003 removed a prohibition on the use of race or ethnicity in the admission of students in the state of Texas. The study examined the role medical school admissions selectivity as it relates to the socioeconomic background during a race neutral admissions cycle in 2005 and a race sensitive admissions cycle in 2006. The results of data analysis found that in a race neutral admissions cycle socioeconomic background was a significant factor in the admission of applicants to medical school. However, it was not a significant factor for applicants from underrepresented minority groups. The analysis also found that socioeconomic background was a significant factor in the admission of applicants to medical school in a race sensitive admissions cycle as well. Finally, the study found that variances in selectivity led to differences in the socioeconomic makeup of entering students across different medical schools. From the data analyzed in this study, it can be argued admission to medical school is in agreement with the sociological literature in that parental socioeconomic status is positively related to academic opportunities for their offspring.
Mental Toughness: An Analysis of Sex, Race, and Mood
Mental toughness has become a focus for researchers as coaches, athletes, and others extol its influence in performance success. In this study I examined mental toughness among collegiate athletes, focusing on its potential relationship to different demographic variables and to the athletes’ mood. Two hundred seventy-two student-athletes representing 12 different sports from a southwestern NCAA Division I university, participated by completing the Sports Mental Toughness Questionnaire (SMTQ), the Brief Assessment of Mood (BAM), and providing demographic information. Analyses of variance (ANOVA) assessed differences in mental toughness scores by sex, race, scholarship status, and starting status. Significant differences in mental toughness emerged between Black – White, male – female, and full – partial – zero scholarship athletes. Pearson correlations showed mental toughness was significantly related to lower levels of anxiety, sadness, anger, confusion, fatigue, and total mood disturbance, and higher levels of vigor.
Mentoring in Higher Education Music Study: Are Good Teachers Mentors?
This quantitative study examined the correlation between how college level music students rated their teachers on the Fowler/O'Gorman Mentor Functions Questionnaire and how they perceived two aspects of their private music lessons: 1) to what extent they perceived their relationship with their teachers as positive, and 2) to what extent they perceived their teachers as good. The respondents for this study were 295 undergraduate and graduate music majors studying at 5 private universities or music schools. Positive correlations were found between the scores on the Mentor Functions Questionnaire (MFQ) and good teachers and positive lesson experiences. No correlation was found between the existence of gender congruity or the lack of gender congruity and the mean score on the MFQ. Respondents reported differences among their teachers' behaviors (p < .05): Role Modeling and Coaching behavior were perceived at significantly higher levels than the other six mentoring behaviors, whereas Friendship and Advocacy behavior was found at significantly lower levels. The behaviors of Personal and Emotional Guidance, Career Development Facilitation, Strategies and Systems Advice, and Learning Facilitation were found at levels closer to the mean. When role modeling and coaching behavior are present, students perceive teachers as good and lessons as positive. It is not necessary to be friends with a student in order to provide a positive lesson experience. Fowler and O'Gorman's mentoring behaviors have implications for improving the mentoring of collegiate music students.
Meta-Analysis of the Impact of After-School Programs on Students Reading and Mathematics Performance
The purpose of this study employing meta-analysis was to assess the impact that after-school programs have on reading and mathematics outcomes. The participants in the primary studies were students in Grades K through 8; years 200 through 2009. The study utilized the theory of change as its theoretical basis. This meta-analysis used the effect size as the standard measure. It began with an overall Cohen's d of .40 for the impact that after-school programs have on reading and mathematics outcomes, and then proceeded to analyze three moderator variables: subject, time periods, and grade level.The findings of the meta-analysis, both overall and sub analyses, show that the independent variable, after-school programs, has an impact on the dependent variable, reading and mathematics. The overall results indicated that after-school programs are educationally significant in the areas of reading and mathematics combined. As for the moderator variable, the results for the areas of (a) subject (reading and mathematics), (b) time period (2000-2002, 2003-2005 and 2006-2009), and (c) grade (middle, and middle plus elementary combined), all indicated educationally significant results. The notable exception was the grade moderator, elementary.This study provides more information for researchers, practitioners and policy makers upon which to make practical research based decisions about after-school programs for the purpose of determining the applicability of such in their educational setting.
Metabolic Engineering in Plants to Control Source/sink Relationship and Biomass Distribution
Traditional methods like pruning and breeding have historically been used in crop production to divert photoassimilates to harvested organs, but molecular biotechnology is now poised to significantly increase yield by manipulating resource partitioning. It was hypothesized that metabolic engineering in targeted sink tissues can favor resource partitioning to increase harvest. Raffinose Family Oligosaccharides (RFOs) are naturally occurring oligosaccharides that are widespread in plants and are responsible for carbon transport, storage and protection against cold and drought stress. Transgenic plants (GRS47, GRS63) were engineered to generate and transport more RFOs through the phloem than the wild type plants. The transgenic lines produced more RFOs and the RFOs were also detected in their phloem exudates. But the 14CO2 labeling and subsequent thin layer chromatography analysis showed that the RFOs were most likely sequestered in an inactive pool and accumulate over time. Crossing GRS47 and GRS63 lines with MIPS1 plants (that produces more myo-inositol, a substrate in the RFO biosynthetic pathway) did not significantly increase the RFOs in the crossed lines. For future manipulation of RFO degradation in sink organs, the roles of the endogenous α-galactosidases were analyzed. The alkaline α-galactosidases (AtSIP1 and AtSIP2 in Arabidopsis) are most likely responsible for digesting RFOs in the cytoplasm and may influence the ability to manipulate RFO levels in engineered plants. Atsip1/2 (AtSIP1/AtSIP2 double-knockout plants) were generated and phenotypically characterized based on seed germination patterns, flowering time, and sugar content to observe the impact on RFO sugar levels. The observations and analysis from these lines provide a basis for further insight in the manipulation of resource allocation between source and sink tissues in plants for future research.
Metabolic Engineering of Raffinose-Family Oligosaccharides in the Phloem Reveals Alterations in Patterns of Carbon Partitioning and Enhances Resistance to Green Peach Aphid
Phloem transport is along hydrostatic pressure gradients generated by differences in solute concentration between source and sink tissues. Numerous species accumulate raffinose-family oligosaccharides (RFOs) in the phloem of mature leaves to accentuate the pressure gradient between source and sinks. In this study, metabolic engineering was used to generate RFOs at the inception of the translocation stream of Arabidopsis thaliana, which transports predominantly sucrose. To do this, three genes, GALACTINOL SYNTHASE, RAFFINOSE SYNTHASE and STACHYOSE SYNTHASE, were expressed from promoters specific to the companion cells of minor veins. Two transgenic lines homozygous for all three genes (GRS63 and GRS47) were selected for further analysis. Sugars were extracted and quantified by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), and 21-day old plants of both lines had levels of galactinol, raffinose, and stachyose approaching 50% of total soluble sugar. All three exotic sugars were also identified in phloem exudates from excised leaves of transgenic plants whereas levels were negligible in exudates from wild type leaves. Differences in starch accumulation or degradation between wild type and GRS63 and GRS47 lines were not observed. Similarly, there were no differences in vegetative growth between wild type and engineered plants, but engineered plants flowered earlier. Finally, since the sugar composition of the phloem translocation stream is altered in these plants, we tested for aphid feeding. When green peach aphids were given a choice between WT and transgenic plants, WT plants were preferred. When aphids were reared on only WT or only transgenic plants, aphid fecundity was reduced on the transgenic plants. When aphids were fed on artificial media with and without RFOs, aphid reproduction did not show differences, suggesting the aphid resistance is not a direct effect of the exotic sugars.
Metamodeling-based Fast Optimization of Nanoscale Ams-socs
Modern consumer electronic systems are mostly based on analog and digital circuits and are designed as analog/mixed-signal systems on chip (AMS-SoCs). the integration of analog and digital circuits on the same die makes the system cost effective. in AMS-SoCs, analog and mixed-signal portions have not traditionally received much attention due to their complexity. As the fabrication technology advances, the simulation times for AMS-SoC circuits become more complex and take significant amounts of time. the time allocated for the circuit design and optimization creates a need to reduce the simulation time. the time constraints placed on designers are imposed by the ever-shortening time to market and non-recurrent cost of the chip. This dissertation proposes the use of a novel method, called metamodeling, and intelligent optimization algorithms to reduce the design time. Metamodel-based ultra-fast design flows are proposed and investigated. Metamodel creation is a one time process and relies on fast sampling through accurate parasitic-aware simulations. One of the targets of this dissertation is to minimize the sample size while retaining the accuracy of the model. in order to achieve this goal, different statistical sampling techniques are explored and applied to various AMS-SoC circuits. Also, different metamodel functions are explored for their accuracy and application to AMS-SoCs. Several different optimization algorithms are compared for global optimization accuracy and convergence. Three different AMS circuits, ring oscillator, inductor-capacitor voltage-controlled oscillator (LC-VCO) and phase locked loop (PLL) that are present in many AMS-SoC are used in this study for design flow application. Metamodels created in this dissertation provide accuracy with an error of less than 2% from the physical layout simulations. After optimal sampling investigation, metamodel functions and optimization algorithms are ranked in terms of speed and accuracy. Experimental results show that the proposed design flow provides roughly 5,000x speedup over conventional design flows. Thus, this dissertation greatly advances the state-of-the-art in mixed-signal design and will assist towards making consumer electronics cheaper and affordable.
“A Metaphor for the Impossibility of Togetherness”: Expansion Processes in Gubaidulina’s First String Quartet
This thesis illustrates how I hear processes of expansion organizing musical materials in the First String Quartet. By employing a flexible approach to expansion and developing models of wedge and additive expansions beyond the bounds of specific voice-leading or rhythmic augmentation procedures, expansion processes can be understood in each of the varied episodes of the quartet. Gubaidulina’s use of expansion processes, embodied organically in pitch, rhythm, form, and physical space, unifies the episodic materials of the First String Quartet and provides an inevitable conclusion to the work’s loose narrative.
Methodological Issues in Malingering Research: The Use of Simulation Designs
The accurate determination of malingering relies on the use of validated and clinically relevant assessment measures. Simulation design is the most often-used research design to accomplish this. However, its external validity is sometimes questioned. The goal of the thesis was to systematically evaluate these major elements: situation, incentives, and coaching. The situation in simulation studies can vary from relevant (academic failure in a college population) to irrelevant (capital murder) for the samples being studied. Incentives refer to the external motivation given to improve simulators' performance and can be positive (extra credit and monetary reward) or negative (extra time and effort). Finally, coaching refers to whether the participant receives any information on detection strategies that are designed to identify feigners. Using a large undergraduate sample in a factorial design, results indicate that a scenario familiar to the participants generally improved the believability of their responses. Coaching also improved the ability to feign convincingly, while incentive type was not associated with any change in scores. The implications of these findings for future research designs and the connection to practice are discussed.
Mexican Mothers’ Experiences with Depression, Intimate Partner Violence, and Immigration: a Mixed Methods Study of Maternal Self-efficacy
This study investigated the relation between maternal self-efficacy, depression, and intimate partner violence among Mexican immigrant and Mexican mothers. The research was conducted using a parallel mixed methods approach including both qualitative and quantitative methods. A total of 136 mothers living in the United States and Mexico completed surveys, and 10 mothers participated in semi-structured interviews. In a regression on maternal depression, living in Mexico as opposed to the U.S., psychological violence, and maternal self-efficacy were significant predictors of maternal depression. In the qualitative data analysis, we found five main themes: perceptions, cultural influence, involvement, resources, and barriers. In this stage of the study, Mexican and Mexican immigrant mothers described in detail their experiences of being a mother, their perceptions of maternal self-efficacy, and the influence of intimate partner violence and depression on their effectiveness as mothers. Overall, Mexican immigrant families appeared to have healthier relationships and greater well-being than Mexican families.
Microstructure Evolution in Laser Deposited Nickel-Titanium-Carbon in situ Metal Matrix Composite
Ni/TiC metal matrix composites have been processed using the laser engineered net shaping (LENS) process. As nickel does not form an equilibrium carbide phase, addition of a strong carbide former in the form of titanium reinforces the nickel matrix resulting in a promising hybrid material for both surface engineering as well as high temperature structural applications. Changing the relative amounts of titanium and carbon in the nickel matrix, relatively low volume fraction of refined homogeneously distributed carbide precipitates, formation of in-situ carbide precipitates and the microstructural changes are investigated. The composites have been characterized in detail using x-ray diffraction, scanning electron microscopy (including energy dispersive spectroscopy (XEDS) mapping and electron backscatter diffraction (EBSD)), Auger electron spectroscopy, and transmission (including high resolution) electron microscopy. Both primary and eutectic titanium carbides, observed in this composite, exhibited the fcc-TiC structure (NaCl-type). Details of the orientation relationship between Ni and TiC have been studied using SEM-EBSD and high resolution TEM. The results of micro-hardness and tribology tests indicate that these composites have a relatively high hardness and a steady-state friction coefficient of ~0.5, both of which are improvements in comparison to LENS deposited pure Ni.
Microwave-Assisted Synthesis, Characterization, and Photophysical Properties of New Rhenium(I) Pyrazolyl-Triazine Complexes
The reaction of the chelating ligand 4-[4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl)-1,3,5-triazin-2-yl]-N,N-diethyl-benzenamine, L, with pentacarbonylchlororhenium by conventional heating method produces the complexes fac-[ReL(CO)3Cl2] and fac-[Re2L(CO)6Cl2] in a period of 48 hours. The use of microwaves as the source of heat and the increase in the equivalents of one of the reactants leads to a more selective reaction and also decreases the reaction time to 1 hour. After proper purification, the photophysical properties of fac-[ReL(CO)3Cl] were analyzed. The solid-state photoluminescence analysis showed an emission band at 628 nm independent of temperature. However, in the solution studies, the emission band shifted from 550 nm in frozen media to 610 nm when the matrix became fluid. These results confirm that this complex possess a phenomenon known as rigidochromism.
Middle School Students in Virtual Learning Environments
This ethnographic study examined middle school students engaged in a virtual learning environment used in concert with face-to-face instruction in order to complete a collaborative research project. Thirty-eight students from three eighth grade classes participated in this study where data were collected through observation of student work within the virtual learning environment, an online survey, and focus group sessions with students involved in the project. Results indicated students found the virtual learning environment to be valuable as a platform to complete a collaborative research assignment because of portability, ease of use, and organization. Embedded resources within the environment were helpful because of the convenience. Other people, including peers and teachers, were the preferred source of help when problems navigating the environment or finding information arose. Students communicated within the virtual learning environment as a social outlet, a way to check in, and a means to offer content related comments. Ideally the study's findings will give insight into student experiences in a virtual learning environment in order to help educators design more effective learning experiences and incorporate useful supports within such environments.
Middle Voice Construction in Burushaski: From the Perspective of a Native Speaker of the Hunza Dialect
This study is about voice system in Burushaski, focusing especially on the middle voice (MV) construction. It claims that the [dd-] verbal prefix is an overt morphological middle marker for MV constructions, while the [n-] verbal prefix is a morphological marker for passive voice. The data primarily come from the Hunza dialect of Burushaski, but analogous phenomena can be observed in other dialects. This research is based on a corpus of 120 dd-prefix verbs. This research has showed that position {-2} on the verb template is occupied by voice-marker in Burushaski. The author argues that the middle marker is a semantic category of its own and that it is clearly distinguished from the reflexive marker in this language. The analysis of the phenomenon in this study only comes from the dialect of Hunza Burushaski, so a lot of research remains to be done on the other three dialects of Burushaski: Yasin dialect, Nagar dialect and Srinagar dialect.
Mikrokosmos and 32 Piano Games: Introducing Contemporary Musical Language and Developing Piano Technique for the Beginning Student
As new musical styles have emerged in the twentieth century with characteristic sounds, chords, forms, meters, and intervals, teachers need to broaden and re-define the way they introduce musical concepts to beginning piano students. The purpose of this study is to offer different instructional possibilities aside from conventional methods of teaching beginning pianists. This is accomplished through a comparison of the two different approaches of the Hungarian composer Béla Bartók and the American composer Ross Lee Finney. Bartók’s Mikrokosmos, a graded set of 153 pieces, and Finney's 32 Piano Games are examined through this paper.
Military-diplomatic Adventurism: Communist China's Foreign Policy in the Early Stage of the Korean War (1950-1951)
The thesis studies the relations of Communist China's foreign policy and its military offensives in the battlefield in Korean Peninsula in late 1950 and early 1951, an important topic that has yet received little academic attention. As original research, this thesis cites extensively from newly declassified Soviet and Chinese archives, as well as American and UN sources. This paper finds that an adventurism dominated the thinking and decision-making of Communist leaders in Beijing and Moscow, who seriously underestimated the military capabilities and diplomatic leverages of the US-led West. The origin of this adventurism, this paper argues, lays in the CCP's civil war experience with their Nationalist adversaries, which featured a preference of mobile warfare over positional warfare, and an opportunist attitude on cease-fire. This adventurism ended only when Communist front line came to the verge of collapse in June 1951.
The Mind's Eye and Other Stories
This collection contains a preface entitled "Of Other Worlds" and the following short stories: "The Mind's Eye," "Waking," "The Conquest of the World," "Persephone," and "Extradition." This creative thesis includes a blend of science fiction and literary realism short stories, which are collectively concerned with questions of time, narration, and the use of language. As well, the preface discusses science fiction theory, narrative strategies such as the use of the first person perspective, and the author's theory of composition.
Miniature Mass Spectrometry: Theory, Development and Applications
As mass analyzer technology has continued to improve over the last fifty years, the prospect of field-portable mass spectrometers has garnered interest from many research groups and organizations. Designing a field portable instrument entails more than the scaling down of current commercial systems. Additional considerations such as power consumption, vacuum requirements and ruggedization also play key roles. In this research, two avenues were pursued in the initial development of a portable system. First, micrometer-scale mass analyzers and other electrostatic components were fabricated using silicon on insulator-deep reactive ion etching, and tested. Second, the dimensions of an ion trap were scaled to the millimeter level and fabricated from common metals and commercially available vacuum plastics. This instrument was tested for use in ion isolation and collision induced dissociation for secondary mass spectrometry and confirmatory analyses of unknowns. In addition to portable instrumentation, miniature mass spectrometers show potential for usage in process and reaction monitoring. To this end, a commercial residual gas analyzer was used to monitor plasma deposition and cleaning inside of a chamber designed for laser ablation and soft landing-ion mobility to generate metal-main group clusters. This chamber was also equipped for multiple types of spectral analysis in order to identify and characterize the clusters. Finally, a portion of this research was dedicated to method development in sample collection and analysis for forensic study. A new method for the analysis of illicit chemistries collected via electrostatic lifting is presented. This method incorporates surface-enhanced Raman microscopy as a prescreening tool for nanoextraction and nanospray ionization mass spectrometry.
Minimalism, Exoticism, and Alternatim in Tarik O’Regan’s Magnificat and Nunc Dimittis and The Ecstasies Above
Abstract British composer Tarik Hamilton O’Regan is a significant choral composer of the early twenty-first century. O’Regan’s Magnificat and Nunc Dimittis and The Ecstasies Above exhibit two notable compositional techniques: minimalism influenced by Steve Reich and exoticism representing Balinese gamelan and Andalusian music. Additionally, Reich joins the technique of minimalism with the Renaissance practice of alternatim. The examination of these works will demonstrate the application of these two compositional techniques and how he integrates them into a textural context to evoke specific historical and cultural practices. Furthermore, this study will provide guidelines for researching and performing O’Regan’s choral works by explaining O’Regan’s stylistic characteristics.
Minority Hiv Rates, Inequality, and the Politics of Aids Funding
Since the 1990s, the HIV/AIDS epidemic has increasingly impacted minority groups in the United States, particularly African Americans. Why is this happening? Comparative studies of developing nations have convincingly established a relationship between concentrated poverty, ethnic boundaries, and lack of effective governmental response as contributing to high levels of infection in those countries. To date, however, no study has sought to apply these insights to the American context. This dissertation endeavors to show that, first, marginalization of U.S. sub-groups most at risk of infection is largely a product of poor health outcomes associated with concentrated urban poverty and economic stratification. Second, this sub-group marginalization is exacerbated by the politics of retrenchment which increasingly privatizes risks onto individuals, states, and non-governmental providers. The net result of these changes is a U.S. health care system too fractured to recognize and respond to changes in HIV/AIDS demographics.
Miranda Reasoning and Competent Waiver Decisions: Are Models of Legal Decision Making Applicable?
Miranda understanding, appreciation, and reasoning abilities are essential to courts' determinations of knowing and intelligent Miranda rights waivers. Despite the remarkable development of Miranda research in recent decades, studies have generally focused on understanding and appreciation of Miranda rights, but have not examined Miranda reasoning and waiver decisions. Therefore, examining the nature of defendants' decisional capacities constitutes a critical step in further developing theoretical and clinical models for competent Miranda waiver decisions. The current study evaluated Miranda waiver decisions for 80 pretrial defendants from two Tulsa-area Oklahoma jails. Previously untested, the current study examined systematically how rational decision abilities affect defendants' personal waiver decisions. Components from general models of legal decision making, such as decisional competence and judgment models, were examined to determine their applicability to Miranda waiver decisions.
Miscegenated Narration: The Effects of Interracialism in Women's Popular Sentimental Romances from the Civil War Years
Critical work on popular American women's fiction still has not reckoned adequately with the themes of interracialism present in these novels and with interracialism's bearing on the sentimental. This thesis considers an often overlooked body of women's popular sentimental fiction, published from 1860-1865, which is interested in themes of interracial romance or reproduction, in order to provide a fuller picture of the impact that the intersection of interracialism and sentimentalism has had on American identity. By examining the literary strategy of "miscegenated narration," or the heteroglossic cacophony of narrative voices and ideological viewpoints that interracialism produces in a narrative, I argue that the hegemonic ideologies of the sentimental romance are both "deterritorialized" and "reterritorialized," a conflicted impulse that characterizes both nineteenth-century sentimental, interracial romances and the broader project of critiquing the dominant national narrative that these novels undertake.
Misinformation About the Misinformation Effect
This study partially replicated the research of Cook, Kwak, Hoffman, & Loftus where they examined post-event activities that induces subjects to pick a wrong person in a forced choice identification procedure. The goal was to investigate if providing a neither option to a match to sample task increases the accuracy of responding. Subjects were asked to study three faces for 10 seconds, after which they were asked to pick out the faces in a forced choice setting where two other faces were presented. Later the subjects were asked to pick out faces in a setting in which they could use a neither option. Results indicated that a generalization effect occurs when identifying faces and the effect is seen as subjects choosing the wrong face. This suggests that when using faces with some similar features in a lineup setting the procedure may cause the subject to pick the wrong person.
Missed Opportunities: Examining The LiteracyExperiences Of African American Students Displaced By Hurricane Katrina.
The purpose of this study was to examine how five African American middle school students, who were displaced by Hurricane Katrina represent their literacy experiences before, during, and after their displacement. Specifically, the two research questions were: (a) What are the stories that these middle school students tell about their lives, before, during, and after their displacement, and (b) What do their stories reveal about their literacy experience before, during, and after their displacement? Narrative Inquiry was the chosen methodology for the study, which allowed the participants to tell their experiences from a first-person perspective. It also encouraged the participants to reflect upon these experiences, in order to give meaning to their thoughts and emotions. Employing a critical lens and perspective, I constructed a narrative profile for each participant, which was then analyzed using these methods. Each narrative profile detailed the literacy experiences of the participants before Hurricane Katrina, during the transition period, and current literacy experiences now that the participants are resettled and attending school in the host city. These data were supplemented by archival data such as report cards, individual education plans (IEPs), and Texas Assessment of Knowledge and Skills (TAKS) scores. Data analysis of the five participants’ literacy experiences revealed common themes. These participants have pleasant memories of school literacy before the storm and mentioned “choice” as a component of those experiences. During the transition period, few or no literacy experiences took place. Hence, there were missed opportunities for the participants to use literacy experiences to make connections to their new world. Participants reported current classroom and school experiences were controlled environments that led to controlled literacy experiences. This compartmentalization of literacy experiences is not consistent with the critical literacy perspective adopted in this study. Their interviews suggested that they that they saw no connection between school literacy and their literacy experiences outside school.
Missing Data Treatments at the Second Level of Hierarchical Linear Models
The current study evaluated the performance of traditional versus modern MDTs in the estimation of fixed-effects and variance components for data missing at the second level of an hierarchical linear model (HLM) model across 24 different study conditions. Variables manipulated in the analysis included, (a) number of Level-2 variables with missing data, (b) percentage of missing data, and (c) Level-2 sample size. Listwise deletion outperformed all other methods across all study conditions in the estimation of both fixed-effects and variance components. The model-based procedures evaluated, EM and MI, outperformed the other traditional MDTs, mean and group mean substitution, in the estimation of the variance components, outperforming mean substitution in the estimation of the fixed-effects as well. Group mean substitution performed well in the estimation of the fixed-effects, but poorly in the estimation of the variance components. Data in the current study were modeled as missing completely at random (MCAR). Further research is suggested to compare the performance of model-based versus traditional MDTs, specifically listwise deletion, when data are missing at random (MAR), a condition that is more likely to occur in practical research settings.
Mist and Microstructure Characterization in End Milling Aisi 1018 Steel Using Microlubrication
Flood cooling is primarily used to cool and lubricate the cutting tool and workpiece interface during a machining process. But the adverse health effects caused by the use of flood coolants are drawing manufacturers' attention to develop methods for controlling occupational exposure to cutting fluids. Microlubrication serves as an alternative to flood cooling by reducing the volume of cutting fluid used in the machining process. Microlubrication minimizes the exposure of metal working fluids to the machining operators leading to an economical, safer and healthy workplace environment. In this dissertation, a vegetable based lubricant is used to conduct mist, microstructure and wear analyses during end milling AISI 1018 steel using microlubrication. A two-flute solid carbide cutting tool was used with varying cutting speed and feed rate levels with a constant depth of cut. A full factorial experiment with Multivariate Analysis of Variance (MANOVA) was conducted and regression models were generated along with parameter optimization for the flank wear, aerosol mass concentration and the aerosol particle size. MANOVA indicated that the speed and feed variables main effects are significant, but the interaction of (speed*feed) was not significant at 95% confidence level. The model was able to predict 69.44%, 68.06% and 42.90% of the variation in the data for both the flank wear side 1 and 2 and aerosol mass concentration, respectively. An adequate signal-to-noise precision ratio more than 4 was obtained for the models, indicating adequate signal to use the model as a predictor for both the flank wear sides and aerosol mass concentration. The highest average mass concentration of 8.32 mg/m3 was realized using cutting speed of 80 Surface feet per minute (SFM) and a feed rate of 0.003 Inches per tooth (IPT). The lowest average mass concentration of 5.91 mg/m3 was realized using treatment 120 SFM and 0.005 IPT. The cutting performance under microlubrication is five times better in terms of tool life and two times better in terms of materials removal volume under low cutting speed and feed rate combination as compared to high cutting speed and feed rate combination. Abrasion was the dominant wear mechanism for all the cutting tools under consideration. Other than abrasion, sliding adhesive wear of the workpiece materials was also observed. The scanning electron microscope investigation of the used cutting tools revealed micro-fatigue cracks, welded micro-chips and unusual built-up edges on the cutting tools flank and rake side. Higher tool life was observed in the lowest cutting speed and feed rate combination. Transmission electron microscopy analysis at failure for the treatment 120 SFM and 0.005 IPT helped to quantify the dislocation densities. Electron backscatter diffraction (EBSD) identified 4 to 8 µm grain size growth on the machined surface due to residual stresses that are the driving force for the grain boundaries motion to reduce its overall energy resulting in the slight grain growth. EBSD also showed that (001) textured ferrite grains before machining exhibited randomly orientated grains after machining. The study shows that with a proper selection of the cutting parameters, it is possible to obtain higher tool life in end milling under microlubrication. But more scientific studies are needed to lower the mass concentration of the aerosol particles, below the recommended value of 5 mg/m3 established by Occupational Safety and Health Administration (OSHA).
Mist Characterization in Drilling 1018 Steel
Minimum quantity lubrication replaces the traditional method of flood cooling with small amounts of high-efficient lubrication. Limited studies have been performed to determine the characteristics of mist produced during MQL. This study investigated the mist concentration levels produced while drilling 1018 steel using a vegetable based lubricant. ANOVA was performed to determine whether speed and feed rates or their interactions have a significant effect on mist concentration levels and particle diameter. It was observed that the concentration levels obtained under all four speed and feed rate combinations studied exceeded the current OSHA and NIOSH standards.
A Mixed Method Analysis of Undergraduate Student-run Public Relations Firms on U.S. College Campuses
Student-run public relations firms are part of collegiate public relations pedagogy, and this study used a mixed-method approach to analyze such firms on U.S. campuses. A listing of campuses with student-run firms was created as part of this study. Through an online survey questionnaire, advisers from 55 of the 119 student-run firms provided data about firm characteristics and observations about student learning and career development. Multiple correspondence analyses was used to see if the firms grouped into clusters and somewhat aligned with previous research by Lee Bush in 2009. Firms clustered into four groups, with the fourth group representing a mix of the other three. One additional finding was that firm characteristics are more similar than dissimilar even when comparing firms of varying years in operation. Analysis of variance to compare characteristics between different types of firms revealed that one type of firm tended to employ students at a higher average number of hours per week (F = 6.61, eta squared=0.16) and one was more likely to be accredited by the Accrediting Council on Education in Journalism and Mass Communications (F = 3.71, eta squared=0.13). Advisers reported mostly positive reflections on observed transformations they see in their student workers and the value of the firm experience including how it helps students in post-graduation job attainment. Responses to a graduate questionnaire is included but, because of low response rate (N = 6), provided only cursory information.
A Mixed-Methods Approach to the Experiences of Non-Offending Parents of Children who have Experienced Sexual Abuse Participating in Child Parent Relationship Therapy (CPRT)
When a child has been sexually abused, the non-offending parent and child may benefit from an intervention aimed at enhancing the parent child relationship. This mixed-methods study examined the process of child parent relationship therapy (CPRT) with non-offending parents of children who had been sexually abused. One purpose of the present study was to examine change in parent-child relationship, child behavior, and parent empathy of non-offending parents whose children have been sexually abused after participation in CPRT. A secondary purpose of this study was to explore subjective experiences of non-offending parents who participate in CPRT. Participants (N = 8) completed 11 weeks of CPRT in either Spanish speaking (n = 4) or English speaking (n = 4) groups. All participants completed pretest and posttest instruments including Child Behavior Checklist, Parenting Stress Index, and Measurement of Empathy in Adult-Child Interaction. Pretest and posttest means were reported but because of small sample size, only descriptive statistics are reported. Possible trends in pretest/posttest mean scores of the quantitative instruments are discussed. All participants also completed a post semi-structured interview to account for the experience of participants qualitatively. Analysis of the qualitative data revealed enhanced parent-child relationships, improved communication, greater acceptance, positive parental internal changes, positive behavioral changes in child, and positive changes in discipline.
A Mixed-methods Study Investigating the Relationship Between Media Multitasking Orientation and Grade Point Average
The intent of this study was to examine the relationship between media multitasking orientation and grade point average. The study utilized a mixed-methods approach to investigate the research questions. In the quantitative section of the study, the primary method of statistical analyses was multiple regression. The independent variables for the study were media multitasking orientation, gender, age, and income. The dependent variable for the study was grade point average. Three out of four independent variables, namely, media multitasking orientation, gender and age were statistically significant predictors of grade point average. In the qualitative section of the study, seven participants were interviewed to determine how individual differences in media multitasking orientation manifest themselves in academic settings.
Modeling Alcohol Consumption Using Blog Data
How do the content and writing style of people who drink alcohol beverages stand out from non-drinkers? How much information can we learn about a person's alcohol consumption behavior by reading text that they have authored? This thesis attempts to extend the methods deployed in authorship attribution and authorship profiling research into the domain of automatically identifying the human action of drinking alcohol beverages. I examine how a psycholinguistics dictionary (the Linguistics Inquiry and Word Count lexicon, developed by James Pennebaker), together with Kenneth Burke's concept of words as symbols of human action, and James Wertsch's concept of mediated action provide a framework for analyzing meaningful data patterns from the content of blogs written by consumers of alcohol beverages. The contributions of this thesis to the research field are twofold. First, I show that it is possible to automatically identify blog posts that have content related to the consumption of alcohol beverages. And second, I provide a framework and tools to model human behavior through text analysis of blog data.
Modeling Place Vulnerability of HIV/AIDS in Texas
This study provides a measurable model of the concept of place vulnerability for HIV/AIDS that incorporates both community and structural level effects using data provided at the ZIP code level from the Texas Department of State Health Services. Sociological literature on the effects of place on health has been growing but falls short of providing an operational definition of the effects of place on health. This dissertation looks to the literature in medical/health geography to supplement sociology’s understanding of the effects of place on health, to the end of providing a measurable model. Prior research that has recognized the complexity of the effects of place still have forced data into one scale and emphasized individual-level outcomes. A multilevel model allows for keeping the associated spatial unit data, without aggregating or parsing it out for convenience of model fit. The place vulnerability model proposed examines how exposure, capacity and potentiality variables all influence an area’s HIV/AIDS count. To capture the effects of place vulnerability at multiple levels, this dissertation research uses a multilevel zero-inflated poisson (MLZIP) model to examine how factors measured at the ZIP code and county both affect HIV/AIDS counts per ZIP code as an outcome. Furthermore, empirical Bayes estimates are mapped to display how well the model fits across the state of Texas. Limitations of this research include the need to incorporate time, more specific predictors, and individual level factors. The methodology developed permits a more thorough understanding of place effects on the spatial variation of HIV/AIDS.
Modeling Student Perception of Web 2.0 Technologies Adoption in Kuwait
The primary focus of this dissertation was to explore students' perceptions of adopting Web 2.0 applications at the School of Basic Education (SBE) in Kuwait. Although Web 2.0 applications are becoming more popular among the digital generation, there is still no evidence of students' perceptions of adopting the innovation of Web 2.0 technologies in Kuwait. The problem this study addresses is that the current status of Web 2.0 technologies usage by academic students has remained educationally unknown in Kuwait. Therefore, there was a need to investigate the extent to which academic students in SBE are aware of and their usage of Web 2.0 technologies, as well as the factors and obstacles that affect using these technologies. Rogers' diffusion of innovation theory (DoI) is employed in this study to specify the factors that influence student perceptions of adopting Web 2.0 applications as learning tools. Data used in this dissertation was gathered via a survey instrument from 350 students at the SBE and was statistically analyzed to find out the answers of the research questions. This study identified the low rate of Web 2.0 awareness and adoption by the students. Descriptive statistical analysis, such as mean scores and standard deviation, were used to analyze and conclude the findings. In the rates of awareness and adoption of Web 2.0, this study also identified no statistically significant differences between the groups of all the demographic variables except the academic field. The statistically significant differences were identified between the academic variables before and after recoding the academic fields into 5 groups. A t-test and one-way ANOVA were used to determine the statistical significance. Several factors were examined in the study to identify their influence on the rate of adoption. The factors included the rate of awareness, Rogers' attributes of innovations, and the obstacles to adopt Web 2.0. The multiple linear regression technique was used to find out the percentage of variance that was explained by three groups of predictors. The overall research model explained 49% of the variance on the rate of adoption. The implications of the findings, in addition to adding empirical evidence to the body of knowledge, highlight areas for professional development, educational and institutional changes and possibility for future research.
Modeling Synergistic Relationships Between Words and Images
Texts and images provide alternative, yet orthogonal views of the same underlying cognitive concept. By uncovering synergistic, semantic relationships that exist between words and images, I am working to develop novel techniques that can help improve tasks in natural language processing, as well as effective models for text-to-image synthesis, image retrieval, and automatic image annotation. Specifically, in my dissertation, I will explore the interoperability of features between language and vision tasks. In the first part, I will show how it is possible to apply features generated using evidence gathered from text corpora to solve the image annotation problem in computer vision, without the use of any visual information. In the second part, I will address research in the reverse direction, and show how visual cues can be used to improve tasks in natural language processing. Importantly, I propose a novel metric to estimate the similarity of words by comparing the visual similarity of concepts invoked by these words, and show that it can be used further to advance the state-of-the-art methods that employ corpus-based and knowledge-based semantic similarity measures. Finally, I attempt to construct a joint semantic space connecting words with images, and synthesize an evaluation framework to quantify cross-modal semantic relationships that exist between arbitrary pairs of words and images. I study the effectiveness of unsupervised, corpus-based approaches to automatically derive the semantic relatedness between words and images, and perform empirical evaluations by measuring its correlation with human annotators.
Modeling the Effects of Chronic Toxicity of Pharmaceutical Chemicals on the Life History Strategies of Ceriodaphnia Dubia: a Multigenerational Study
Trace quantities of pharmaceuticals (including carbamazepine and sertraline) are continuously discharged into the environment, which causes concern among scientists and regulators regarding their potential long-term impacts on aquatic ecosystems. These compounds and their metabolites are continuously interacting with the orgranisms in various life stages, and may differentially influence development of embryo, larvae, juvenile, and adult stages. To fully understand the potential ecological risks of two candidate pharmaceutical chemicals (carbamazepine (CBZ) and sertraline (SERT)) exposure on survival, growth and reproduction of Ceriodaphnia dubia in three sucessive generations under static renewal toxicity test, a multigenerational approach was taken. Results indicate that SERT exposure showed higher sensitivity to chronic exposure to C. dubia growth and reproduction than CBZ exposure. The lowest concentration to affect fecundity and growth was at 50 µg L-1 SERT in the first two generations. These parameters become more sensitive during the third generation where the LOEC was 4.8 µg L-1. The effective concentrations (EC50) for the number of offspring per female, offspring body size, and dry weight were 17.2, 21.2, and 26.2 µg SERT L-1, respectively. Endpoints measured in this study demonstrate that chronic exposure of C. dubia to SERT leads to effects that occur at concentrations an order of magnitude higher than predicted environmental concentrations indicating potential transgenerationals effects. Additionally, a process-based dynamic energy budget (DEB) model is implemented to predict the simulated effects of chronic toxicity of SERT and CBZ to C. dubia individual behavior at laboratory condition. The model‘s output indicates the ecotoxicological mode of action of SERT exposure, which acts on feeding or assimilation with an effect that rapidly saturates at higher concentrations. Offspring size decreases with the toxic effects on feeding, and offspring number is thus less affected than total investment in reproduction. Consequently, CBZ affects direclty in reproduction which are captured by DEBtox model as increased embryonic hazard and reproduction cost as well as growth and maintenance costs. Furthermore, stress factor linearly increased not only with increasing chemical concentrations but also with exposure time. The DEBtox model establishes a cumulative life history consequence of multigenerational exposure to CBZ and SERT. This approach provides a tool to which to understand the effect of chemical to the individual organism and predict the population level effects in ecological risk assessment of the emerging contaminants.
Modeling the Relationship Between Golden Algae Blooms in Lake Texoma, Usa, Versus Nearby Land Use and Other Physical Variables
Pyrmnesium parvum, commonly known as golden algae, is an algal species that under certain circumstances releases toxins which can lead to fish kills and the death of other economically and ecologically important organisms. One of the major objectives of the study was to investigate whether a relationship exists between land use and Prymnesium parvum abundance in littoral sites of Lake Texoma, USA. Another objective was to investigate whether a relationship exists between other physical variables and counts of P. parvum. Lastly, developing a valid model that predicts P. parvum abundance was an objective of the study. Through stepwise regression, a small but highly significant amount of the variation in P. parvum counts was found to be explained by wetlands, soil erodibility and lake elevation. The developed model provides insight for potential golden algae management plans, such as maintaining wetlands and teaching land owners the relationship between soil erosivity and golden algae blooms.
Modeling Transition Metal Catalysts for Small Molecule Activation and Functionalization
There is a high demand for the development of processes for the conversion of ubiquitous molecules into industrially useful commodities. Transition metal catalysts are often utilized for the activation and functionalization of small organic molecules due to their diverse nature and proven utility with a myriad of chemical transformations. The functionalization of methane (CH4) and dinitrogen (N2) to methanol (CH3OH) and ammonia (NH3) respectively is of particular interest; however, both methane and dinitrogen are essentially inert due to the inherit strength of their bonds. In this dissertation a series of computational studies is performed to better understand the fundamental chemistry behind the functionalization of methane and the activation of dinitrogen in a homogeneous environment. A catalytic cycle is proposed for the oxy-functionalization of methane to methanol. The cycle consists of two key steps: (1) C-H activation across a metal-alkoxide bond (M-OR), and (2) regeneration of the M-OR species through an oxy-insertion step utilizing external oxidants. The C-H activation step has been extensively studied; however, the latter step is not as well understood with limited examples. For this work, we focus on the oxy-insertion step starting with a class of compounds known to do C-H activation (i.e., Pt(II) systems). Computational studies have been carried out in an attempt to guide experimental collaborators to promising new systems. Thus, the majority of this dissertation is an attempt to extend transition metal mediated C-O bond forming reactions to complexes known to perform C-H activation chemistry. The last chapter involves a computational study of the homogeneous cleavage of N2 utilizing iron-?-diketiminate fragments. This reaction has been studied experimentally, however, the reactive intermediates were not isolated and the mechanism of this reaction was unknown. Density functional theory (DFT) calculations are carried out to elucidate the mechanism of the reductive cleavage of N2 via the sequential addition of iron- ?-diketiminate fragments to N2 to form a bis-nitride (N3-) intermediate. The role of potassium promoters on the dinitrogen and bis-nitride species is also investigated.
Modeling Transition Metal Chemistry for Catalytic Functionalization of Molecules
The diversity of transition metal complexes allows for a wide range of chemical processes to be mediated by the metal, from catalysis to surface chemistry. Investigations into the structure and electronic configuration of transition metal complexes allow for tuning of desired species by modifications to the ligands and/or metals to achieve more efficient thermodynamics and kinetics for the process of interest. Transition metals, often used in catalysts for a number of important processes, require detailed descriptions of intermediates, transition states and products to fully characterize a reaction mechanism(s) in order to design more active and efficient catalysts. Computational investigations into inorganic catalysts are explored with the aim of understanding the activity of each species and how modifications of supporting ligands, co-ligands and metals vary the interaction along the reaction pathway. Reported results give important insight into the development of the most active complexes in addition to determining the least active complexes to aid experimental development. This report first investigates the mechanisms of two unique transfer reactions: 1) formation of low coordinate nickel-nitrene ((P~P)Ni=NR; P~P = 1,2-bis(dihydrophosphino)-ethane or 1,2-bis(difluoromethylphosphino)-ethane) complexes as catalysts for nitrogen atom transfer and 2) oxidation of a triphosphorus niobium complex, [(η2-P3SnPh3)Nb(OMe)3], for the transfer of the phosphorus synthon, Ph3SnP3. These reactions have utility in the synthesis of nitrogen and phosphorus containing molecules, respectively, and the results presented provide mechanistic insight into the synthesis of the organometallic intermediates. Additionally, a computational approach towards rational catalyst design was performed on the ruthenium based hydroarylation catalyst TpRu(CO)(Ph) [Tp = hydrido-tris(pyrazolyl)borate]. Targeted modifications at the Tp, metal and co-ligand (CO) sites were studied in order to tune the electronics and sterics of the catalyst. Modifications, through computational methods, provided a more cost- and time-efficient way to study the impact of modifications, which provided direct input into attractive synthetic targets. The research described heir in highlights the use of computational chemistry methodologies, specifically DFT, in collaboration with experimental results, for the accurate description of reaction geometries and factors influencing the thermodynamics and kinetics of the systems. Valuable insight is gained by treating inorganic complexes with theoretical methods and additionally provides a fast, cheap way to predict and understand the chemistry of such complex systems.
Modern Api Design and Physical Computing Techniques in Just Intonation Performance Practice
approached previously by both Harry Partch and Ben Johnston, and proposes the decoupling of interface and sound production as a way forward. The design and implementation of a software instrument and a hardware prototype are described, both using a simple API for variable tuning instruments. The hardware prototype uses physical computing techniques to control the tuning of a string with a servo motor, while the software instrument exists entirely in a web browser. Finally, potential algorithms for clients of the API are presented, and the effectiveness of the hardware prototype is evaluated by measuring its pitch accuracy.
Modest Musorgsky's Early Songs: Uncommon Lyricisms Within a Simple Framework
Modest Musorgsky is considered a composer of masterful vocal, symphonic, and piano works. His songs and song cycles distinguish themselves as evocative of the broad spectrum of Russian experience. However, Musorgsky's early songs have not received as much attention as his larger works, such as Boris Godunov or Pictures at an Exhibition. Musorgsky's early songs, from 1857-1867, show the composer's affinity for lyrical expression, be it brightly melodious, impassioned, or within a comical or satirical vein. He portrays Russian life through a mixture of different genres such as the Russian romance, the ballad, the operatic aria, and also vaudeville. This study focuses on Musorgsky's choice of texts, his penning of several of them, and the way he incorporates them within each song.