You limited your search to:

  Partner: UNT Libraries
 Collection: UNT Theses and Dissertations
Landscape Ecological Characteristics of Habitat of the Red-cockaded Woodpecker
Geographic information systems (GIS) technology was used to analyze factors influencing habitat use by an endangered species, the red-cockaded woodpecker. The study area was the western part of the Raven Ranger District of the Sam Houston National Forest, Texas. The factors considered included both structural characteristics and spatial relationships among stands of trees in the habitat.
Landscape forest modeling of the Luquillo Experimental Forest, Puerto Rico.
This thesis contributes to modeling the dynamics of forest community response to environmental gradients and disturbances over a mountain landscape. A gap model (FACET) was parameterized for species of various forest types (Tabonuco, Colorado, Dwarf and Palm), for many terrain conditions and was modified and extended to include species response to excess soil moisture and hurricanes. Landscape cover types were defined by dominance of species of each forest type and canopy height. Parameters of the landscape model (MOSAIC) were calculated from multiple runs of FACET. These runs were determined by combining terrain variables (elevation and soil) and hurricane risk. MOSAIC runs were analyzed for distribution patterns. Geographic Information Systems software was used to process terrain variables, hurricane risk and MOSAIC model output.
Language Achievement of Fifth, Eigth, and Eleventh-Grade Students as Determined by an Analysis of Written Compositions
The purpose set for this study was to define tentative standards of achievement through the analysis of compositions written by fifth, eighth, and eleventh-grade students in terms of quantity and quality.
Language and Identity in Post-1800 Irish Drama
Using a sociolinguistic and post-colonial approach, I analyze Irish dramas that speak about language and its connection to national identity. In order to provide a systematic and wide-ranging study, I have selected plays written at approximately fifty-year intervals and performed before Irish audiences contemporary to their writing. The writers selected represent various aspects of Irish society--religiously, economically, and geographically--and arguably may be considered the outstanding theatrical Irish voices of their respective generations. Examining works by Alicia LeFanu, Dion Boucicault, W.B. Yeats, and Brian Friel, I argue that the way each of these playwrights deals with language and identity demonstrates successful resistance to the destruction of Irish identity by the dominant language power. The work of J. A. Laponce and Ronald Wardhaugh informs my language dominance theory. Briefly, when one language pushes aside another language, the cultural identity begins to shift. The literature of a nation provides evidence of the shifting perception. Drama, because of its performance qualities, provides the most complex and complete literary evidence. The effect of the performed text upon the audience validates a cultural reception beyond what would be possible with isolated readers. Following a theoretical introduction, I analyze the plays in chronological order. Alicia LeFanu's The Sons of Erin; or, Modern Sentiment (1812) gently pleads for equal treatment in a united Britain. Dion Boucicault's three Irish plays, especially The Colleen Bawn (1860) but also Arrah-na-Pogue (1864) and The Shaughraun (1875), satirically conceal rebellious nationalist tendencies under the cloak of melodrama. W. B. Yeats's The Countess Cathleen (1899) reveals his romantic hope for healing the national identity through the powers of language. However, The Only Jealousy of Emer (1919) and The Death of Cuchulain (1939) reveal an increasing distrust of language to mythically heal Ireland. Brian Friel's Translations (1980), supported by The Communication Cord (1982) and Making History (1988), demonstrates a post-colonial move to manipulate history in order to tell the Irish side of a British story, constructing in the process an Irish identity that is postnational.
Language and the Art of Writing
Access: Use of this item is restricted to the UNT Community.
I start writing by conjuring up an image in my mind. Sometimes it will be something that I have thought about for a while, sometimes it will be something that I sit around attempting to create. Either way, it is simply the idea that I need in order to get started. People will say, "Just sit down and write" which I can do, but it does not mean I will end up anywhere worthwhile. In my writing I need a focus. I need an idea or just one image to get me writing and I can base an entire story off of that one image. I think the reason this works for me is because in my mind it is an illustration and always something that is vibrant and unique. I want the image to stand out and to mean something because I feel that it comes to me for a specific reason, I just have to piece it all together and let the characters and plot unfold for themselves. People often say this, that the characters end up running the story. I think this is true, but in my case my stories are not so driven by character or plot as they are by language. A language driven piece can be a difficult thing to manipulate because it needs to have some direction and some purpose other than just being pleasing to the ear/mind/reader. And what is the point of a language driven piece?
A Language and Visual Interface to Specify Complex Spatial Pattern Mining
Access: Use of this item is restricted to the UNT Community.
The emerging interests in spatial pattern mining leads to the demand for a flexible spatial pattern mining language, on which easy to use and understand visual pattern language could be built. It is worthwhile to define a pattern mining language called LCSPM to allow users to specify complex spatial patterns. I describe a proposed pattern mining language in this paper. A visual interface which allows users to specify the patterns visually is developed. Visual pattern queries are translated into the LCSPM language by a parser and data mining process can be triggered afterwards. The visual language is based on and goes beyond the visual language proposed in literature. I implemented a prototype system based on the open source JUMP framework.
A Language Arts Program for Ninth-Grade Slow Learning Pupils
The problem with which this investigation is concerned is that of discerning the traits of a group of pupils who have low levels of learning and developing for them a more appropriate "differentiated program" of instruction in language arts.
Language Behaviors and Social Strategies of English as Second Language and English as Primary Language Preschool Children During Computer Assisted Instruction Experiences
This study describes the language behaviors and social strategies of English as Second Language (ESL) and English as Primary Language (EPL) pre-kindergarten students during cooperative Computer Assisted Instruction (CAI) experiences. Thirty-three pre-kindergarten subjects ages four to five years, were videotaped at two personal computers during self-selected center time. The sources of data for this descriptive study were a parent computer survey, videotapes, a subject interview derived from the Young Children's Computer Inventory, and written records.
Language Choice in the ESL and FL Classrooms: Teachers and Students Speak Out
This paper compares English as a second language (ESL) and foreign language (FL) teachers' and students' perspectives regarding target language (TL) and first language (L1) use in the respective classrooms. Teachers and students were given questionnaires asking their opinions of a rule that restricts students' L1 use. Questionnaires were administered to 46 ESL students, 43 FL students, 14 ESL teachers, and 15 FL teachers in Texas secondary public schools. Results were analyzed using SPSS and R. Results demonstrated an almost statistical difference between perspectives of ESL and FL students regarding TL and L1 use, while teacher results demonstrated no statistical difference between the groups. Students had a more positive perspective of the rule than teachers.
Language Contact in the Inner City: the Acquisition of AAVE Features by Bilingual Hispanic Adolescents
Sociolinguists working in Northern urban areas have shown that Hispanics who come in contact with African Americans sometimes acquire features of African American vernacular English (AAVE). However, the acquisition of AAVE features by Hispanics in the South has yet to be documented. Specifically, no one has studied the kind of English that Hispanics in Texas are acquiring. The present study investigates this issue through research in an inner-city area of Dallas: Oak Cliff. During the past twenty-five years, the population of Oak Cliff has changed from a largely African American community to include a substantial number of Hispanics. Though their neighborhoods remain fairly separate, sports and gangs provide an arena for extended contact. This study investigates the extent to which AAVE grammatical features are being acquired by bilingual Hispanic adolescents who hang out with African Americans. The analysis for this paper focuses on the relationship between contact and depth of acquisition of AAVE syntactic constraints on the use the copula (is/are, be). Preliminary results show that be+V+ing as an habitual form has been incorporated into the grammar of these subjects, suggesting fundamental changes towards an AAVE grammatical system.
Language Drift in English : Gender Loss and Semantic Change
In parallel passages from Old and Middle English and in noun cognates from Modern English, Old English, and Modern German, the most discernible elements of language drift are gender loss and word meaning change, respectively. They can be observed, discussed, and calculated to show a definite progression toward the development of Modern English.
The Language of Color in Shelley's Prometheus Unbound
On the premise that examination of a poet's language can provide a valid and significant approach to the study of a work of art, this thesis proposes to make such a study of Prometheus Unbound, the major poetical work of Percy Bysshe Shelley, with specific attention to his use of color language.
Language Policy, Protest and Rebellion
The hypothesis that language discrimination contributes to protest and/or rebellion is tested. Constitutional language policy regarding administrative/judicial, educational and other matters is measured on three separate scales developed for this study; the status of each minority group's language under its country's policy is measured by another set of scales. Protest and rebellion variables are taken from Gurr's Minorities at Risk study. Findings include an indication that group language status contributes positively to protest and rebellion until a language attains moderate recognition by the government, at which point status develops a negative relationship with protest and rebellion, and an indication that countries with wider internal variations in their treatment of language groups experience higher levels of protest and rebellion on the part of minority groups.
The Laplace Transformation
A set of definitions, theorems and proofs to describe the Laplace transformation.
The Larval Lipids of the Chironomid Midge Glyptotendipes Barbipes (Staeger)
This problem was concerned with determining the total lipid content and individual lipid composition of the larvae of a local chironomid, Glyptotendipes barbipes (Staeger).
Laser Cutting Machine: Justification of initial costs
The Industrial Laser is firmly established in metalcutting as the tool of choice for many applications. The elevator division of Montgomery KONE Inc., in an effort to move towards quality, ontime, complete deliveries and 100% customer satisfaction, decided to invest in new equipment to improve manufacturing processes. A huge investment is proposed for a laser-cutting machine. It is the responsibility of Manufacturing Engineering to direct the management by justifying its benefits, which includes payback time and financial gains. Factors such as common line cutting, automated material handling system and cutting time were involved in justification of the initial cost of a laser-cutting machine. Comparative statistics on appropriate factors accurately determine and justify the initial cost of a laser-cutting machine.
Laser Deposition, Heat-treatment, and Characterization of the Binary Ti-xmn System
The present research seeks to characterization of an additively manufactured and heat-treated Ti-xMn gradient alloy, a binary system that has largely been unexplored. In order to rapidly assess this binary system, compositionally graded Ti-xMn (0<x<15 wt%) specimens were fabricated using the LENS (Laser Engineered Net Shaping) and were subsequently heat-treated and characterized using a wide range of techniques. Microstructural changes with respect to the change in thermal treatments, hardness and chemical composition were observed and will be presented. These include assessments of both continuous cooling, leading to observations of both equilibrium and metastable phases, including the titanium martensites, and to direct aging studies looking for composition regimes that produce highly refined alpha precipitates – a subject of great interest given recent understandings of non-classical nucleation and growth mechanisms. The samples were characterized using SEM, EDS, TEM, and XRD and the properties probed using a Vickers Microhardness tester.
Laser Modified Alumina: a Computational and Experimental Analysis
Laser surface modification involves rapid melting and solidification is an elegant technique used for locally tailoring the surface morphology of alumina in order to enhance its abrasive characteristics. COMSOL Multiphysics® based heat transfer modeling and experimental approaches were designed and used in this study for single and multiple laser tracks to achieve densely-packed multi-facet grains via temperature history, cooling rate, solidification, scanning electron micrographs, and wear rate. Multi-facet grains were produced at the center of laser track with primary dendrites extending toward the edge of single laser track. The multiple laser tracks study indicates the grain/dendrite size increases as the laser energy density increases resulting in multiplying the abrasive edges which in turn enhance the abrasive qualities.
Laser Surface Modification on Az31b Mg Alloy for Bio-wettability
Laser surface modification of AZ31B Magnesium alloy changes surface composition and roughness to provide improved surface bio-wettability. Laser processing resulted in phase transformation and grain refinement due to rapid quenching effect. Furthermore, instantaneous heating and vaporization resulted in removal of material, leading the textured surface generation. A study was conducted on a continuum-wave diode-pumped ytterbium laser to create multiple tracks for determining the resulting bio-wettability. Five different laser input powers were processed on Mg alloy, and then examined by XRD, SEM, optical profilometer, and contact angle measurement. A finite element based heat transfer model was developed using COMSOL multi-physics package to predict the temperature evolution during laser processing. The thermal histories predicted by the model are used to evaluate the cooling rates and solidification rate and the associated changes in the microstructure. The surface energy of laser surface modification samples can be calculated by measuring the contact angle with 3 different standard liquid (D.I water, Formamide, and 1-Bromonaphthalen). The bio-wettability of the laser surface modification samples can be conducted by simulated body fluid contact angle measurement. The results of SEM, 3D morphology, XRD, and contact angle measurement show that the grain size and roughness play role for wetting behavior of laser processing Mg samples. Surface with low roughness and large grain size performs as hydrophilicity. On the contrast, surface with high roughness and small grain size performs as hydrophobicity.
Laser Surface Treatment of Amorphous Metals
Amorphous materials are used as soft magnetic materials and also as surface coatings to improve the surface properties. Furthermore, the nanocrystalline materials derived from their amorphous precursors show superior soft magnetic properties than amorphous counter parts for transformer core applications. In the present work, laser based processing of amorphous materials will be presented. Conventionally, the nanocrystalline materials are synthesized by furnace heat treatment of amorphous precursors. Fe-based amorphous/nanocrystalline materials due to their low cost and superior magnetic properties are the most widely used soft magnetic materials. However, achieving nanocrystalline microstructure in Fe-Si-B ternary system becomes very difficult owing its rapid growth rate at higher temperatures and sluggish diffusion at low temperature annealing. Hence, nanocrystallization in this system is achieved by using alloying additions (Cu and Nb) in the ternary Fe-Si-B system. Thus, increasing the cost and also resulting in reduction of saturation magnetization. laser processing technique is used to achieve extremely fine nanocrystalline microstructure in Fe-Si-B amorphous precursor. Microstructure-magnetic Property-laser processing co-relationship has been established for Fe-Si-B ternary system using analytical techniques. Laser processing improved the magnetic properties with significant increase in saturation magnetization and near zero coercivity values. Amorphous materials exhibit excellent corrosion resistance by virtue of their atomic structure. Fe-based amorphous materials are economical and due to their ease of processing are of potential interest to synthesize as coatings materials for wear and corrosion resistance applications. Fe-Cr-Mo-Y-C-B amorphous system was used to develop thick coatings on 4130 Steel substrate and the corrosion resistance of the amorphous coatings was improved. It is also shown that the mode of corrosion depends on the laser processing conditions. The microstructure evolution and the corrosion mechanisms operating are evaluated using post processing and post corrosion analysis.
The Last Laugh: Selected Edwardian Punch Cartoons of Edward Linley Sambourne
The illustrative work of Edward Linley Sambourne for Punch magazine during the period 1901-1910 addresses a myriad of political topics prevalent during the Edwardian period in British history. This thesis examines two of those topics - Women's Suffrage and Socialism - through their artistic treatment by one of Britain's most influential periodicals. Through a study of the historical context and iconography of selected cartoons-of-the-week, one is better equipped to understand and appreciate the meaning, message, and humor in the cartoons. Chapter 1 introduces the Sambourne, Punch magazine, and the Edwardian period in general. Chapters 2 and 3 discuss four Women's Suffrage cartoons and four Socialism cartoons respectively. Chapter 4 draws conclusions regarding Sambourne's techniques as a cartoonist as well as the relationship between the text and image in his illustrations.
Late adolescents' parental, peer, and romantic attachments as they relate to affect regulation and risky behaviors.
The current study examined the relationships among attachment styles to parent, peer, and romantic partner, ability to regulate emotion, as well as engagement in sexual behaviors and substance use. Attachment theory and previous research suggests that an individual learns how to manage emotions through the modeling of appropriate techniques and a stable sense of self-worth. These two aspects develop through a secure attachment bond with an important figure. When an individual does not have a secure attachment bond in which to practice adaptive affect regulation strategies, he/she may attempt to manage emotions through external means, such as sexual behaviors or substance use. Overall, results supported these associations, with some notable exceptions. Across attachment sources a secure attachment style was related to lower levels of psychological distress and less engagement in substance use. In contrast to the findings from earlier studies, affect regulation did not mediate the relationship between attachment and substance use, and engagement in sexual behaviors was not significantly related to either attachment style or affect regulation.
Latent Transition Analysis of Pre-service Teachers' Efficacy in Mathematics and Science
This study modeled changes in pre-service teacher efficacy in mathematics and science over the course of the final year of teacher preparation using latent transition analysis (LTA), a longitudinal form of analysis that builds on two modeling traditions (latent class analysis (LCA) and auto-regressive modeling). Data were collected using the STEBI-B, MTEBI-r, and the ABNTMS instruments. The findings suggest that LTA is a viable technique for use in teacher efficacy research. Teacher efficacy is modeled as a construct with two dimensions: personal teaching efficacy (PTE) and outcome expectancy (OE). Findings suggest that the mathematics and science teaching efficacy (PTE) of pre-service teachers is a multi-class phenomena. The analyses revealed a four-class model of PTE at the beginning and end of the final year of teacher training. Results indicate that when pre-service teachers transition between classes, they tend to move from a lower efficacy class into a higher efficacy class. In addition, the findings suggest that time-varying variables (attitudes and beliefs) and time-invariant variables (previous coursework, previous experiences, and teacher perceptions) are statistically significant predictors of efficacy class membership. Further, analyses suggest that the measures used to assess outcome expectancy are not suitable for LCA and LTA procedures.
Latin Mass for Choir, Orchestra, Soprano and Mezzo-Soprano Soloists
The Latin Mass is a musical composition in five movements, scored for large choir, standard orchestra, and two soloists. The movements are the standard parts of the Roman Catholic Mass Ordinary. The language is set mainly in Latin with two exceptions: the Kyrie movement is set in Greek (which is the standard Roman Catholic setting), and the Credo is simultaneously recited in English and sung in Latin. The work is scored using conventional notation techniques and employs rather conservative technical demands on both the choir and orchestra. No extended techniques are required of any of the performers. It is set in a modal harmonic language.
Latin Vocabulary Acquisition : An Experiment Using Information-processing Techniques of Chunking and Imagery
The purpose of the study was to determine the effect on student performance and attitude toward high school Latin by Latin I students when provided with vocabulary instruction through chunking and imagery.
Latino Students’ School Counseling Needs: an Exploratory Needs Assessment
The purpose of this study was to examine Latino/a student preferences for school counselor activities. The primary focus of research was to determine what school counseling activities Latino/a students perceived as important and which school counseling activities Latino/a high school students perceived as satisfying. The researcher pursued this purpose through administration of a survey instrument developed by the researcher. The instrument consisted of 14 demographic items and 42 5-point Likert scale items based on the domains described in the ASCA’s national model and current literature on experiences of Latino/a adolescents. The sample was comprised of 210 Latino/a high school students from five high schools in three school districts in the suburbs of a large Southwestern U.S. metroplex. The study population consisted of 94 female and 115 male participants ranging in age from 14 to 20 years old with the median age of 17.54 years. Overall, students preferred school counseling activities focusing on college and career readiness. According to the results of this study, students indicated that although they believed college and career activities to be important, they were not satisfied with how their school counselors provided those activities. Multiple regression analyses were utilized to determine which demographic variables were significant predictors of respondents’ perceptions of importance. Results indicated student perceptions of importance did not vary across grades, economic levels, genders, or cultural differences. The results, limitations, and suggestions for school counseling programs were provided within the report.
Latino success stories in higher education: A qualitative study of recent graduates from a health science center.
This study used qualitative research, particularly life history analysis, to determine the personal pathways of success for Latino students who chose to enter a health science center for graduate study and who graduated. By giving voice to individual success stories of Latino students, some of the influences on the life pathways of these graduates were determined. For the purposes of this study, success was defined as graduation from a health science center with either a doctor of philosophy, doctor of public health or doctor of osteopathic medicine degree. Four research subjects agreed to participate in this study from a possible 11 students from the graduating class of 2004-2005 at this health science center. Data were gathered through multiple in-depth interviews of the students themselves over a period of no more than one month for each participant. Data were analyzed using the mind mapping technique and Padilla's unfolding matrix. Findings indicate that each participant traveled a different pathway to achieve educational success although similarities did exist across participants. The influences of family background, cultural background, educational background and personal perceptions and goals did affect the pathways of these four Latino graduates. While three of four participants indicated that family was the most important influence on their academic success, all participants related the importance of family to their success, although their definitions of family seemed to vary and included the concepts of education, culture, and personal perceptions and goals. The concepts of family support of education and a culture of education within the family unit emerged as similar themes among study participants. Other similarities among participants were a high academic self-concept, a strong internal locus of control, the ability to create academic community, and a positive view of potentially negative situations. Individual themes emerged from the narratives within each category for each participant. The impact of previous studies on student success, using undergraduate models, was reviewed, and one influence was found among the study participants that had not been used in previous models - health. Implications of findings from this study for educational policy, programs, and practice are discussed.
Because lattice theory is so vast, the primary purpose of this paper will be to present some of the general properties of lattices, exhibit examples of lattices, and discuss the properties of distributive and modular lattices.
The Launching of an Accelerated School: A Case Study
The purpose of this qualitative study was to explore the readiness, planning, training and implementation stages of staff development in the implementation of the Accelerated Schools Program in a suburban elementary school. The research questions focused on how the school became interested in the accelerated program; the steps that were taken to make the school ready to accept the program; the training made available to the staff, parents and students; how teacher approval and acceptance were achieved; and how the implementation was initiated and to what degree.
The law and human rights: is the law a mere parchment barrier to human rights abuse?
This study is the first systematic global analysis of the impact of law on human rights, analyzing the impact of twenty-three constitution provisions and an international covenant on three measures of human rights behavior, over the period of 1976-1996. Three sets of constitutional provisions are analyzed, including 1) ten provisions for individual freedoms and due process rights, 2) nine provisions for elements of judicial independence and 3) four provisions that outline procedures for states of emergency. Additionally, the impact of the International Covenant on Civil and Political Rights on actual human rights behavior is analyzed. Each of these areas of law are evaluated individually, in multiple models in which different elements vary. For example, some models control for democracy with different measures, others divide the data into the Cold War and post-Cold War eras, and some test constitutional indices. Finally, all provisions are simultaneously analyzed in integrated models. Provisions for fair and public trials are consistently shown to decrease the probability of abuse. An index of four freedoms (speech, religion, association, and assembly) decreases the probability of abuse somewhat consistently. Three of the provisions for judicial independence are most consistent in reducing the probability of abuse: the provisions for exclusive judicial authority, for the finality of judges' decisions, and banning exceptional courts. Two of four states of emergency provisions decrease abuse as international lawyers have argued: the provisions for legislative declaration of the emergency and the ban against dissolving the legislature during an emergency. However, two of the provisions are shown to hurt human rights practices: the duration and the derogation provisions. The International Covenant on Civil and Political Rights does not demonstrate a statistically significant impact. While the performance of the constitutional provisions is less than legal scholars would hope, their combined impact over time are shown to be quite large, relative to the impacts of other factors shown to affect human rights abuse.
The Law Concerning Trade Regulations Prio to the Twentieth Century
This thesis discusses trade regulations throughout history.
Lawrence Weiner's Concerto for Guitar and Orchestra: Analysis and Performance Considerations
The purpose of this dissertation is to provide an introduction to the composer, Lawrence Weiner, and to his Concerto for Guitar and Orchestra, one of the many neglected guitar concerti that merits closer study and more frequent performances. Weiner, a prolific and prominent composer in the South Texas region, composed the concerto in 1986. The concerto was never published. This dissertation is the first attempt to study Weiner's Concerto for Guitar and Orchestra to date. This study provides insight into the compositional style of Weiner, and the understanding and performing of this work. The compositional language of this concerto is examined through an analysis of the aspects of form, harmonic/tonal scheme and thematic development. A performance edition and suggestions that are approved by the composer are also presented.
Layered Double Hydroxides and the Origins of Life on Earth
Access: Use of this item is restricted to the UNT Community.
A brief introduction to the current state of research in the Origins of Life field is given in Part I of this work. Part II covers original research performed by the author and co-workers. Layered Double Hydroxide (LDH) systems are anion-exchanging clays that have the general formula M(II)xM(III)(OH)(2x+2)Y, where M(II) and M(III) are any divalent and trivalent metals, respectively. Y can be nearly any anion, although modern naturally occuring LDH systems incorporate carbonate (CO32-), chloride (Cl-), or sulfate (SO42-) anions. Intercalated cobalticyanide anion shows a small yet observable deviation from local Oh symmetry causing small differences between its oriented and non-oriented infrared spectra. Nitroprusside is shown to intercalate into 2:1 Mg:Al LDH with decomposition to form intercalated ferrocyanide and nitrosyl groups of an unidentified nature. The [Ru(CN)6]4- anion is shown to intercalate into layered double hydroxides in the same manner as other hexacyano anions, such as ferrocyanide and cobalticyanide, with its three-fold rotational axis perpendicular to the hydroxide sheets. The square-planar tetracyano-nickelate(II), -palladate(II), and platinate(II) anions were intercalated into both 2:1 and 3:1 Mg:Al layered double hydroxides (LDH). The basal spacings in the 2:1 hosts are approximately 11 Å, indicating that the anions are inclined approximately 75 degrees relative to the hydroxide layers, while in the 3:1 hosts the square-planar anions have enough space to lie more nearly parallel to the LDH cation layers, giving basal spacings of approximately 8 Å. It has been found that the LDH Mg2Al(OH)6Cl catalyzes the self-addition of cyanide, to give in a one-pot reaction at low concentrations an increased yield of diaminomaleonitrile and in addition, at higher ($0.1M) concentrations, a purple-pink material that adheres to the LDH. We are investigating whether this reaction also occurs with hydrotalcite itself, what is the minimum effective concentration of cyanide, and what can be learned about the products and how they compare with those reported at high HCN concentrations in the absence of catalyst.
Layered Double Hydroxides as Anion- and Cation-Exchanging Materials
Layered double hydroxides (LDH) have been principally known as anion-exchanging, clay-like materials for several decades, and continues to be the main driving force for current and future research. The chemical interactions of LDH, with transition metallocyanides, have been a popular topic of investigation for many years, partly due to the use of powder x-ray diffraction and infrared spectroscopy as the main characterization tools. Each transition metallocyanide has a characteristic infrared stretching frequency that can be easily observed, and their respective sizes can be observed while intercalated within the interlayer of the LDH. The ability of LDH to incorporate metal cations or any ions/molecules/complexes, that have a postive charge, have not been previously investigated, mainly due to the chemical and physical nature of LDH. The possibility of cationic incorporation with LDH would most likely occur by surface adsorption, lattice metal replacement, or by intercalation into the LDH interlayers. Although infrared spectroscopy finds it main use through the identification of the anions incorporated with LDH, it can also be used to study and identify the various active and inactive bending and stretching modes that the metal hydroxide layers have.
Layered Double Hydroxides: Morphology, Interlayer Anion, and the Origins of Life
Access: Use of this item is restricted to the UNT Community.
The preparation of layered double hydroxides via co-precipitation of a divalent/trivalent metal solution against a base results in 1 mm LDH particles with a disorganized metal lattice. Research was performed to address these morphological issues using techniques such as Ostwald ripening and precipitation via aluminate. Another interesting issue in layered double hydroxide materials is the uptake and orientation of anions into the interlayer. Questions about iron cyanide interlayer anions have been posed. Fourier transform infared spectroscopy and powder x-ray diffraction have been used to investigate these topics. It was found that factors such as orientation, anion charge, and anion structure depended on the divalent/trivalent metal ratio of the hydroxide layer and reactivity time. The cyanide self-addition reaction is an important reaction of classical prebiotic chemistry. This reaction has been shown to give rise to amino acids, purines and pyrimidines. At cyanide concentrations similar to that expected on the early earth, hydrolysis to formamide rather than self-addition occurs. One theory to alleviate this side reaction is the use of minerals or clays that are thought to concentrate and catalyze prebiotics of interest. Layered double hydroxides have been studied as a catalyst for this reaction.
Layered Double Hydroxides: Synthesis, Characterization, and Interaction of Mg-Al Systems with Intercalated Tetracyanonickelate(II)
The square-planar tetracyanonickelate(II) anion was intercalated into 2:1 and 3:1 Mg-Al layered double hydroxide systems (LDHs). In the 2:1 material, the anion holds itself at an angle of about 30° to the layers, whereas in the 3:1 material it lies more or less parallel to the layers. This is confirmed by orientation effects in the infrared spectra of the intercalated materials and by X-ray diffraction (XRD) data. The measured basal spacings for the intercalated LDH hosts are approximately 11 Å for the 2:1 and approximately 8 Å for the 3:1. The IR of the 2:1 material shows a slight splitting in the ν(CN) peak, which is suppressed in that compound's oriented IR spectrum, indicating that at least some of the intercalated anion's polarization is along the z-axis. This effect is not seen in the 3:1 material. A comparison between chloride LDHs and nitrate LDHs was made with respect to intercalation of tetracyanonickelate(II) anions. Both XRD data and atomic absorption spectroscopy (AAS) data of the LDH tetracyanonickelates confirms that there are no significant differences between the products from the two types of starting materials. The presence of a weak ν(NO) peak in the IR spectra of those samples made from nitrate parents indicates the presence of small amounts of residual [NO3]- in those systems. Small amounts of Cl- present in the chloride-derived samples, while perhaps detectable using AAS, would not be detectable in this manner. An attempted synthesis of Mg-Al LDH carbonates starting from reduced Mg and Al was unsuccessful due to pH constraints on hydroxide solubility in the solvent system used (water). The pH required to precipitate Al(OH)3 in the system was too high to allow precipitation of Mg(OH)2. Consequently, we found it impossible to have both of the required metal hydroxides present simultaneously in the system. An additional synthesis using a halogen as an oxidizing agent also failed to produce material of any characterizable quality.
Laying the foundation for successful non-academic writing: Professional communication principles in the K-5 curricula of the McKinney Independent School District.
Traditionally, K-5 students' writing has had a primarily academic aim-to help students master concepts and express themselves. Even if students take a professional writing course later, they typically do not have the opportunity to practice-over the long period of time mastery requires-the non-academic writing skills they will be required to use as part of their jobs and in their civic life. Based on a limited K-5 study, Texas' McKinney Independent School District is doing a good job of preparing students at the elementary-school level in the areas of collaboration and presentation. A fair job of helping elementary-school students understand the communication situation, define audience, clarify purpose, gather and evaluate resources, and test usability. [And] a poor job of helping elementary-school students with analysis and organization. With their teachers' help, K-5 students eventually grasp the communication situation and can broadly identify their audience and purpose, but they do not appear to select words, format, communication style, or design based on that audience and purpose. Their writer-based focus affects their presentations as well, although they do present frequently. If teachers routinely incorporated audience and purpose considerations into every aspect of communication assignments (format, communication style, design), students would be better prepared for non-academic communication. Texas pre-service teachers practice the types of documents they will write on the job but do not receive training in design or style. Likewise, they practice researching, collaborating, and presenting but receive little training in those skills. If Texas K-5 teachers are to supplement the curriculum with professional writing principles, as trends suggest they should, education programs need to focus on these principles in their pre-service teacher curriculum. Professional writing principles need to become part of ingrained writing patterns because these are the skills that will best serve students after they graduate, both in their careers and civic lives. Understanding how to tailor communication for audience and purpose; how to effectively collaborate; how to select, evaluate, analyze, and organize information efficiently and productively; and how to format presentations effectively requires practice over a long period of time.
A Layman's Interpretation of the Provisions of a 20-Year Pay Life Insurance Policy
This thesis presents an attempt to simplify the language used in life insurance provisions.
Layout-accurate Ultra-fast System-level Design Exploration Through Verilog-ams
This research addresses problems in designing analog and mixed-signal (AMS) systems by bridging the gap between system-level and circuit-level simulation by making simulations fast like system-level and accurate like circuit-level. The tools proposed include metamodel integrated Verilog-AMS based design exploration flows. The research involves design centering, metamodel generation flows for creating efficient behavioral models, and Verilog-AMS integration techniques for model realization. The core of the proposed solution is transistor-level and layout-level metamodeling and their incorporation in Verilog-AMS. Metamodeling is used to construct efficient and layout-accurate surrogate models for AMS system building blocks. Verilog-AMS, an AMS hardware description language, is employed to build surrogate model implementations that can be simulated with industrial standard simulators. The case-study circuits and systems include an operational amplifier (OP-AMP), a voltage-controlled oscillator (VCO), a charge-pump phase-locked loop (PLL), and a continuous-time delta-sigma modulator (DSM). The minimum and maximum error rates of the proposed OP-AMP model are 0.11 % and 2.86 %, respectively. The error rates for the PLL lock time and power estimation are 0.7 % and 3.0 %, respectively. The OP-AMP optimization using the proposed approach is ~17000× faster than the transistor-level model based approach. The optimization achieves a ~4× power reduction for the OP-AMP design. The PLL parasitic-aware optimization achieves a 10× speedup and a 147 µW power reduction. Thus the experimental results validate the effectiveness of the proposed solution.
Leader Developmental Readiness of Generation Y in the Training Industry
Members of Generation Y in the training and development industry will be required to assume leadership roles as Baby Boomers retire, yet little empirical research exists regarding how best to prepare them for leadership. The purpose of this study was to examine differences in leader developmental readiness between generational cohorts in the training industry, specifically Baby Boomers, Generation X, and Generation Y. Leader developmental readiness provided a definition of developmental readiness for leaders using the five constructs (learning goal orientation, developmental efficacy, self-awareness, leader complexity, and metacognitive ability). A volunteer sample was compiled from members of the ASTD National LinkedIN group (n = 636). Results were analyzed using structured means analysis with maximum likelihood (ML) estimation. Generational cohorts demonstrated differences in leader developmental readiness. Baby Boomers indicated statistically and practically higher metacognitive ability and developmental efficacy than Generation Y. Results demonstrated statistically and practically higher leader complexity in Generation Y and both Generation X and Baby Boomers. These results should inform leader development practitioners as they continue to use existing methods in preparing the different generations for leader development interventions while pointing to possible needs to increase the metacognitive ability and developmental efficacy in Generation Y and ensure accurate perception of leader complexity in those individuals. Further research would be helpful to confirm or refute findings and expand on the target population for enhanced generalizability.
Leader Emergence and Effectiveness in Virtual Workgroups: Dispositional and Social Identity Perspectives
In today's global competitive environment, many organizations utilize virtual workgroups to overcome geographic and organizational boundaries. Research into their dynamics has received the attention of scholars within multiple disciplines, and the potential for an integrative approach to the study of virtual workgroups exists. This dissertation is a first step towards such an approach. The primary aim of this research is to examine antecedent and contextual factors that affect the emergence and effectiveness of leaders in virtual workgroups. To achieve this aim, an integrative model assembled from theory and empirical findings in leadership, management, social identity, and communications research is posited. Hypothesized relationships depicted in the model identify key dispositional and contextual variables linked to leader emergence, member behavior, and leader effectiveness within virtual workgroups. This study employed a nonexperimental research design, in which leader emergence and social identity manifest as naturally occurring phenomena. Data collection occurred via two web-based surveys administered at different points in time. Hypothesized relationships were tested utilizing correlational and hierarchical moderated multiple regression analyses. The findings of this dissertation suggest that traits, such as personality and cognitive ability, are not associated with leader emergence in virtual workgroups. In addition, the results indicate that the exhibition of relationship-oriented leader behaviors enhances group identity. In turn, identification is associated with increases in perceptions of leader effectiveness and decreases in counterproductive behavior exhibited by group members. This dissertation exposes an important limitation to the application of trait leadership theory. It also demonstrates the importance of relationship-oriented behavior and social identity in virtual contexts. Further, it advances an integrative theoretical model for the study of virtual workgroup phenomena. These contributions should assist and inform other researchers, as well as practitioners, interested in leadership and group member behavior in virtual workgroups.
Leadership and sustainable change: The relationship between leadership practices of principals and reculturing schools as professional learning communities.
This study examined the relationships between leadership practices of principals and strength of schools as sustainable professional learning communities. Strength of schools as professional learning communities was measured using the Professional Learning Communities Assessment; leadership practices were measured using the Leadership Practices Inventory both Self and Observer protocols. Findings indicated that neither principal's self-perceptions of their leadership practices nor teachers' assessments of their principals' leadership practices were related to strength of schools as professional learning communities. Findings did indicate ten specific leadership behaviors of principals that appear to be more highly related to strength of schools as learning communities. Further analysis which focused on the two strongest learning community schools and the two weakest learning community schools indicated that three specific leadership behaviors within Kouzes and Posner's practices of modeling the way and enabling others to act appear to be the most strongly related to reculturing schools as sustainable professional learning communities. Principals who set a personal example of what they expect of others are most likely to lead schools that function as strong learning communities. Additionally, principals who build consensus around a common set of values are also most likely to lead strong learning communities. Finally, principals who develop cooperative relationship with co-workers are most likely to lead schools that function as strong learning communities.
Leadership, Ascendancy, and Gender
By the year 2000 women will constitute more than 50 percent of the workforce in the United States, yet their representation in top management and executive-level positions continues to hover in the single digits. This “glass ceiling,” which is conceptualized as limiting women's advancement into these roles, has been the subject of much debate and research over the last fifteen years. As both an equal rights and key competitive issue, the topic of women and leadership is gaining ever-increasing emphasis and momentum in American corporations. Although leadership skills have been advocated as a key human capital/person-centered variable leading to managerial ascendancy for women, the empirical research directly investigating this link is virtually non-existent. This longitudinal study proposed to measure the strength of this relationship using a matched sample of male and female managers. Eighty-five subjects, from the same U.S. based health-care products corporation, had previously participated in a multirater assessment process where seven different facets of their leadership skills were evaluated. Time two data were collected on four objective measures of ascendancy: percent change in salary, number of promotions (job moves) either offered or accepted, change in number of direct reports, and change in number of indirect reports. Multivariate analysis of covariance indicated that perceived leadership ability did lead to increased ascendancy, specifically in terms of percent salary change, for the female managers, but not for the males. Multiple regressions indicated that the female managers were not rewarded, necessarily, for gender congruent behavior in this organization, while male managers did appear to be rewarded more so on that particular dimension. Implications of these findings for female managers in the workplace were discussed.
Leadership Communication Among Kindergarten Children in a Structured Play Environment
This study examines the enactment of leadership communication during videotaped play sessions of thirty kindergarten children. Eighteen of the children demonstrated skills in a cluster of five specific leadership behaviors. All five coders agreed that these eighteen children were sometimes leaders of their individual triad. The coders further agreed that the leadership in the triads flowed from one child to another as the session progressed. The study concluded that leadership is a facilitative process that is fluid rather than statically centered in one or more participants.
Leadership Concepts of Air Force Reserve Officer Training Corps Students
The purpose of this study is to determine the concepts held by college students in the Air Force Reserve Officer Training Corps concerning leadership. An attempt will be made to indicate the relative importance of these concepts of leadership as determined by the college students. Also, the opinions of the different classes--freshmen, sophomores, juniors, and seniors concerning these concepts will be obtained.
Leadership Effectiveness: Investigating the Influences of Leader Sex, Gender, and Behaviors on Self and Other Perceptions
Though increasing numbers of women are entering the workforce, a disproportionate number of women are placed into upper level management positions. Social role and role congruity theory both posit that women in leadership positions are likely to face more negative criticism than men in leadership positions. The purpose of the current study was to examine the influence of gender roles on leader behaviors as well as leaders' self perceived effectiveness. The study also examined third party raters' views of female and male leaders. Videotapes of forty-seven mixed sex groups with randomly appointed male and female leaders were used to examine leader behaviors as well as raters' effectiveness ratings. Leaders' self perceived effectiveness ratings were also used. Gender roles of the leaders were assessed using the Bem Sex Role Inventory (BSRI). Results of a MANOVA indicated that leader gender roles did not lead to differences in leader behaviors exhibited among those in feminine, masculine, and androgynous groups. For female leaders, femininity was not related to feminine behaviors. Unexpectedly, for male leaders, masculinity was inversely related to masculine behaviors. With regard to raters' effectiveness ratings of the leaders, no differences were found in ratings based on leader gender. Further, for female leaders, degree of femininity and masculinity was not related to raters' effectiveness ratings. However, exploratory analyses indicated a significant positive relationship to exist between raters' effectiveness ratings of female leaders and total time female leaders spoke. A significant inverse relationship was found between raters' effectiveness ratings and frequency of speech initiations used among female leaders. Significant correlations between male and female leaders' self perceived effectiveness ratings and self perceived gender roles were found. Specifically, masculinity was positively related to female leaders self perceived effectiveness while femininity was negatively related to male leader self perceived effectiveness. Overall, the results of the current study were not consistent with social role theory and role congruity theory. Implications for organizations and women's career development are discussed. Limitations and suggestions for future directions in research are presented.
Leadership Frames of Female Presidents of American Research Universities
This study used case studies to examine the leadership frames of female presidents of four-year, public and private, coeducational research institutions both from the Intensive and Extensive Carnegie classifications within the United States. The population (N=30) surveyed was sent the Leadership Orientation Questionnaire (Self) developed from the previous research conducted by Lee Bolman and Terrance Deal. The Bolman and Deal leadership frame theory condensed existing organizational theories into a four-frame perspective consisting of a structural, human resource, political, and symbolic frame. Bolman and Deal theorized that the ability to use more than one frame is considered to be critical to the success of leaders and intensify that leader's capacity for making decisions and taking effective actions. The Leadership Orientation Questionnaire (Self) contains five sections that include rating scales for personal demographics, the four frames, eight leadership dimensions, and management and leadership effectiveness. The research questions sought to identify the demographic characteristics and academic histories of the survey participants and the associations between these variables, the leadership frames represented among the survey participants, and how many, and which, of the four frames the survey participants use collectively. This study allowed its participants to examine their perceptions of their own leadership frames in order to analyze the frame that dominates the way certain universities communicate. Thirteen of the thirty presidents (43%) completed and returned the survey. Survey participants who had 20 or more years of experience were more likely to exhibit the human resource or symbolic frame as their dominant style; presidents whose years of experience numbered less than 20 years exhibited a mulitframe perspective in their decision-making process. Overall, this research found that the survey participants exhibited most often the human resource frame, followed by the symbolic, structural, and political frames.
The Leadership Path of R. Jan LeCroy
Access: Use of this item is restricted to the UNT Community.
Recent studies reveal that a considerable number of U.S. community college leaders will be retiring in the next several years. The concern is that with the large turnover, history, culture, and important lessons of leadership will be lost. The current research on the lives of presidents, their career paths, and experiences in community college leadership centers on approaches to the study of leadership at the macro level. Limited research exists in the published literature that reports and analyzes the development of individuals as community college leaders at the micro level. This results in a gap regarding understanding leadership development and strategies to prepare leaders. This study addresses this gap by providing a critical description of the leadership development of one individual who became a community college chancellor and who the literature on the community context indicates contributed to the local and national context for community colleges. Biography is gaining prominence as a legitimate and viable tool in the study of leadership. Few biographical studies currently exist which focus on leadership development in context at the micro level. This dissertation is a biographical, qualitative study of the leadership path and legacy of R. Jan LeCroy, a community college leader. The study combined two viable approaches to biographical inquiry: a scholarly chronicle and the realist approach. Data included the use of primary and secondary sources and included interviews, document analysis, and archival data such as newspaper articles, memos, and minutes of meetings. The data were analyzed and the findings discussed using the theoretical framework of Gronn's (1993) career model of leadership, Vaughan's (1986) study of the career paths of presidents, and Sullivan's (2001) study of four distinct generations of community college leaders. The leadership path of R. Jan LeCroy paralleled the four stages in Gronn's (1993) career model of leadership; he shared characteristics of the presidents surveyed in Vaughan's (1986) study; and he fit the profile of the second generation of community college leaders as described by Sullivan (2001).
Leadership preferences of a Generation Y cohort: A mixed methods study.
Access: Use of this item is restricted to the UNT Community.
Presently there are four generational cohorts in the workplace. Born from 1977 to 1997, the youngest cohort group, referred to as Generation Y (or Gen Y) in this study, has 81 million members, of whom over 29 million are already in the workplace. The importance of leader-subordinate relationships in the workplace has been confirmed; in recognizing this, leaders must identify and adapt to the changing era-shaped needs of employees, who cannot fully participate in organizational life if their most urgent needs are not being met. Because Gen Y employees are only now entering the workforce, little is actually known about the workplace needs of this cohort group. This study attempted to determine leadership needs of a Gen Y cohort as a means to enhance workplace relationships in the 21st century organization. A sequential, mixed methods study was employed to explore leadership preferences of a Gen Y cohort. Initially, focus group interviews were used to generate leadership themes. Based on these themes, an instrument was designed, and Gen Y business students from three higher education institutions were surveyed. Confirmatory factor analysis using LISREL software was used to test the themes. The driving force behind this research design was to build a foundation of understanding through inductive research (qualitative) and to test and enrich the foundation through deductive means (quantitative).
Leadership Styles and Cultural Sensitivity of Department Chairs at Texas Public Universities
As the U.S. population diversifies, so do its higher education institutions. Leadership at these institutions should be prepared for this diversification of students, faculty, and staff. The purpose of this study was to gain greater knowledge about the leadership styles and cultural sensitivity of department chairs. Survey research was used to determine if department chairs’ leadership styles correlated with their cultural sensitivity. The target population was department chairs from public universities in the state of Texas. The survey was distributed to 406 randomly selected department chairs. The participants completed three measures: Leadership Behavior Description Questionnaire (LDBQ) for leadership style, the Intercultural Sensitivity Scale (ISS) for cultural sensitivity, and a demographic questionnaire (gender, age range, race/ethnicity, and years of service as department chair). The sample included 165 usable surveys (40% return rate). The department chairs were primarily male (72%), White (78%), and over 50 (71%) years of age. First, a statistically significant negative correlation (r = -.431, p < .0001) occurred between LBDQ overall scores and overall ISS scores: As chairs scored higher on leadership ability, they scored lower on intercultural sensitivity. Second, leadership style by demographic variable displayed mixed results. No significant difference was found for leadership style by age, gender, years of service, or region of service. For ethnicity, White participants scored significantly lower than Minority participants on the LBDQ scales of consideration (t [162] = -2.021, p = .045), structure (t [162] = -2.705, p = .008), and overall (t [162] = -2.864, p = .005). Minority participants might work more diligently to increase their leadership abilities based on their higher LDBQ scores. Third, findings on intercultural sensitivity by demographic variable were mixed. No statistical significance was observed between any of the ISS scales and age, gender, years of service, and region. For ethnicity, Minority participants’ scores showed significantly lower intercultural sensitivity than White participants scores on two of six ISS subscales: interaction enjoyment (t = -2.46, p = .015) and respect (t = 2.107, p = .037). It was concluded that the Minority and White department chairs’ leadership style and intercultural sensitivity differences could be due in part to differences in the chairs’ ethnic affiliations, associated cultural backgrounds, and views of dominant versus non-dominant cultures. Recommendations for study are included.