Search Results

The neutron electric form factor to Q² = 1.45 (GeV/c)²

Description: The nucleon elastic electromagnetic form factors are fundamental quantities needed for an understanding of nucleon and nuclear electromagnetic structure. The evolution of the Sachs electric and magnetic form factors with Q2, the square of the four-momentum transfer, is related to the distribution of charge and magnetization within the nucleon. High precision measurements of the nucleon form factors are essential for stringent tests of our current theoretical understanding of confinement within the nucleon. Measurements of the neutron form factors, in particular, those of the neutron electric form factor, have been notoriously difficult due to the lack of a free neutron target and the vanishing integral charge of the neutron. Indeed, a precise measurement of the neutron electric form factor has eluded experimentalists for decades; however, with the advent of high duty-factor polarized electron beam facilities, experiments employing polarization degrees of freedom have finally yielded the first precise measurements of this fundamental quantity. Following a general overview of the experimental and theoretical status of the nucleon form factors, a detailed description of an experiment designed to extract the neutron electric form factor from measurements of the neutron's recoil polarization in quasielastic 2H(e, e')1H scattering is presented. The experiment described here employed the Thomas Jefferson National Accelerator Facility's longitudinally polarized electron beam, a magnetic spectrometer for detection of the scattered electron, and a neutron polarimeter designed specifically for this experiment. Measurements were conducted at three Q2 values of 0.45, 1.13, and 1.45 (GeV/c)2, and the final results extracted from an analysis of the data acquired in this experiment are reported and compared with recent theoretical predictions for the nucleon form factors.
Date: February 1, 2004
Creator: Plaster, Bradley
Partner: UNT Libraries Government Documents Department

Interim Evaluation of the UNT/Dallas Public Schools Leadership Development Program: A Working Model

Description: The purpose of this study was to determine if, after one year of operation, the UNT/Dallas Public Schools Leadership Development Program was progressing in accordance with the goals set out for the program. Questionnaires administered to 26 interns and 10 mentor principals and follow-up focus group interview sessions provided answers to the study's five research questions that explored the following: selection process; how interns' involvement in campus-based decision-making had changed; how mentor principals' perceptions toward interns had changed; and how administrative interns' perceptions of themselves and educational administration had changed. Findings from this study revealed the selection process provided the Dallas Public Schools an opportunity to select teacher-leaders from the district and to include a representative number of minority and women candidates for participation in the program. An area of weakness was seven interns with low GRE scores were admitted through an appeals process at the university. Another weakness revealed the majority of interns had been assigned more duties and responsibilities at the schools, but only 4 of 26 interns were being allowed to participate in any campus-based decision-making processes that could have an impact on school improvements. The study found the role of the mentor principal to be the most important factor in determining the satisfaction and success of the interns in the program. The embedded internship proved to be a disadvantage for the interns and principals, as the majority reported not having enough time to spend on administrative activities. Interns reported growth in personal and professional maturity and gained knowledge about the world of educational leadership. All 26 interns expressed the desire to become administrators in Dallas Public Schools upon completion of the program. Further research should include comparison studies between graduates of restructured programs and graduates of traditional programs to determine if there is a difference in …
Date: May 2004
Creator: Newman, Carol A.
Partner: UNT Libraries

An Observational Investigation of On-Duty Critical Care Nurses' Information Behavior in a Nonteaching Community Hospital

Description: Critical care nurses work in an environment rich in informative interactions. Although there have been post hoc self-report survey studies of nurses' information seeking, there have been no observational studies of the patterns and content of their on-duty information behavior. This study used participant observation and in-context interviews to describe 50 hours of the observable information behavior of a representative sample of critical care nurses in a 20-bed critical care hospital unit. The researcher used open, in vivo, and axial coding to develop a grounded theory model of their consistent pattern of multimedia interactions. The resulting Nurse's Patient-Chart Cycle describes nurses' activities during the shift as centering on a regular alternation with the patient and the patient's chart (various record systems), clearly bounded with nursing "report" interactions at the beginning and the end of the shift. The nurses' demeanor markedly changed between interactions with the chart and interactions with the patient. Other informative interactions were observed with other health care workers and the patient's family, friends and visitors. The nurses' information seeking was centered on the patient. They mostly sought information from people, the patient record and other digital systems. They acted on or passed on most of the information they found. Some information they recorded for their personal use during the shift. The researcher observed the nurses using mostly patient specific information, but they also used some social and logistic information. They occasionally sought knowledge based information. Barriers to information acquisition included illegible handwriting, difficult navigation of online systems, equipment failure, unavailable people, social protocols and mistakes caused by multi-tasking people working with multiple complex systems. No formal use was observed of standardized nursing diagnoses, nursing interventions, or nursing outcomes taxonomies. While the nurses expressed respect for evidence-based practice, there clearly was no time or opportunity for reading research …
Date: May 2004
Creator: McKnight, Michelynn
Partner: UNT Libraries

Sunlight readability and luminance characteristics of light-emitting diode push button switches.

Description: Lighted push button switches and indicators serve many purposes in cockpits, shipboard applications and military ground vehicles. The quality of lighting produced by switches is vital to operators' understanding of the information displayed. Utilizing LED technology in lighted switches has challenges that can adversely affect lighting quality. Incomplete data exists to educate consumers about potential differences in LED switch performance between different manufacturers. LED switches from four different manufacturers were tested for six attributes of lighting quality: average luminance and power consumption at full voltage, sunlight readable contrast, luminance contrast under ambient sunlight, legend uniformity, and dual-color uniformity. Three of the four manufacturers have not developed LED push button switches that meet lighting quality standards established with incandescent technology.
Date: May 2004
Creator: Fitch, Robert J.
Partner: UNT Libraries

Ghosts and Lovers

Description: Ghosts and Lovers is a collection of short stories told from the points-of-view of four related characters. Travis is a bisexual restaurant owner who fears commitment and longs for the idealistic version of love that he remembers from his past. Ezra, his boyfriend, is an artist struggling to accept the inherent imperfections of life. Travis's ex-girlfriend, Beth, attempts to come to terms with the life that she has chosen for herself. Her husband, Richard, deals with feelings of helplessness as he watches the events of his life unfold before him. By depicting the events of the story from multiple perspectives, the collection attempts to create a more objective view of reality than is ordinarily possible in fiction. An introductory preface examines the role of unreliable narrators and how reality is presented in fiction.
Date: May 2004
Creator: Federer, Lisa M.
Partner: UNT Libraries

The Effects of Sign Language on the Vocal Responses of a Child with Autism.

Description: Sign language is an effective form of alternative communication for persons with autism and other developmental disabilities. Only a few studies have systematically measured the effects of sign language on the vocal responses of its users. This study employed a multiple baseline design to evaluate the effects of sign language on the vocal responses of a four-year-old boy with autism. Results indicate that a reinforcement contingency placed only on sign responses is inadequate for maintaining vocal responses. When a reinforcement contingency is placed on sign responses as well as vocal responses that the user is capable of emitting in verbal imitation, both sign and vocal responses are maintained. Results are discussed in terms of the need for a reinforcement contingency placed on vocal and sign responses, the effects of teaching procedures on response variability, and the need for future research to examine procedures utilized to teach sign language to persons within the developmental disabilities population.
Date: May 2004
Creator: Scarbro-McLaury, Jill
Partner: UNT Libraries

Effects of Methanol, Atrazine, and Copper on the Ultrastructure of Pseudokirchneriella Subcapitata (Selenastrum Capricornutum).

Description: The toxicity of methanol, atrazine, and copper to Pseudokirchneriella subcapitata (Korshikov) Hindák historically referred to as Selenastrum capricornutum Printz were determined following 96 hrs growth in a modified Goram's growth media. Methanol and atrazine inhibited fluorescence readings in the cultures by 50% (IC50) at concentrations of 2% and 82 µg/l respectively. These toxicity values compared favorably to other published reports. The IC50 for copper was 160 µg/l which is substantially higher than reported values. This is understandable because of the high chelating capacity of Goram's media. The use of stereologically derived relative volume in the chloroplasts, mitochondria, lipid bodies, phosphate bodies, and nucleus was investigated to determine if it could be used as a sensitive endpoint in toxicity tests. The volume fractions for the chloroplasts and mitochondria were normally distributed in control cells while the nuclei, phosphate bodies, and lipid bodies were not. The chloroplasts were the most dominate organelle occupying a mean relative volume of 46% and mitochondria occupied a mean relative volume of 3%. The nucleus and phosphate bodies occupied a median relative volume of 7% and 2% respectively. The lipid bodies were rare in section profile and no meaningful median relative volume could be calculated. Up to the 82nd percentile of sectioned profiles contained no recognizable lipid bodies. The use of relative volume was not a sensitive endpoint for use in toxicity tests. No significant differences in relative volume could be detected in the nucleus or phosphate bodies following any treatment. Limited differences were detected in the mitochondria, chloroplasts, and lipid bodies. The only significant differences that appear to be biologically significant occurred in methanol treated cells where an increase in the lipid bodies' relative volume was apparently concentration dependent. Significant differences in the relative volume of mitochondria and chloroplasts do not appear to be biologically significant.
Date: May 2004
Creator: Garrett, David C.
Partner: UNT Libraries

A Performer's Analysis of Maurice Ravel's Chansons madécasses: A Lecture Recital, Together with Three Recitals of Selected Works of B. Britten, R. Schumann, S. Barber, T. Pasatieri, F. Poulenc, G. Verdi, T. Arne, and Others

Description: In his song cycle, Chansons madécasses (1926), a chamber work for voice, piano, flute, and cello, Maurice Ravel combines twentieth-century musical experimentation and exoticism with the late nineteenth-century style characteristics present in the vocal elements and instrumentation. Because early twentieth-century music appears to be closely connected to modern concerns, performers may tend to dismiss the style and technique of the early twentieth century as simply "old-fashioned" rather than examine and consider those elements as resources and valuable tools for interpreting and presenting authentic performances. The focus of this research includes a discussion of the historical, social, and textual implications of the music and poetry; a formal musical analysis of the work, including comparisons of an early twentieth-century, mid-century, and late twentieth-century recordings with regard to the use of vibrato and portamento in the voice, cello, and flute; and an examination of Chansons madécasses for elements of authentic Malagasy music and poetry. The paper also suggests methodologies for performance practice which reflect the results of these analyses. The beginnings of the rejection of traditional form - harmonic, rhythmic, and melodic structures - found in the early part of the century began to free composers and performers to explore musical presentations that gain their power not only from startling and unexpected elements of exoticism and interpretation but also from their romantic roots, which spurred the desire for a raw, even melodramatic, emotionalism. Ravel, without sacrificing the integrity of his native language, is able to blend his text with his accompaniment in a way that uses both the poem and the music to advance the "plot" and emotion of the narration, producing what might be described as a near perfect union of form and theme, structure and idea.
Date: May 2004
Creator: Ellis, Diana Lea
Partner: UNT Libraries

Mary/merry and horse/hoarse: Mergers in Southern American English

Description: Phonetic mergers in American English have been studied throughout the last half century. Previous research has contributed social and phonetic explanations to the understanding of front and back vowel mergers before /l/, front vowel mergers before nasals and phonetically unconditioned back vowel mergers. Using data from the Linguistic Atlas of the Gulf States (LAGS) and the Linguistic Atlas of the Middle and South Atlantic States (LAMSAS), this thesis examines the spread of the front vowel mergers in Mary and merry and the back vowel mergers in horse and hoarse. The two complementary sources of data allow for a social and phonetic approach to the examination of the merger.
Date: May 2004
Creator: Ehrhardt, Brooke
Partner: UNT Libraries

Op. 34: Evidence of Arnold Schoenberg's Musikalische Gedanke

Description: Composition for Arnold Schoenberg is a comprehensible presentation of a musical idea (musikalische Gedanke); the totality of a piece represents the idea. For tonal works, he defines Gedanke as a process of resolving the "tonal relation" or "tonal problem." Contrary to the numerous tonal examples illustrating the notion of Gedanke, Schoenberg hardly expounds on the Gedanke principle for his atonal and twelve-tone repertoires. This study reevaluates Schoenberg's compositional philosophy and aesthetics including Gedanke, comprehensibility, Grundgestalt, and developing variation in light of his compositional practices in Begleitungsmusik zu einer Lichtspielszene, Op. 34. Although Schoenberg denies the existence of a tonal problem and hierarchy among pitches in twelve-tone compositions, the registral placement found in Op. 34 indicates certain functionality assigned to each pitch-class, producing a sense of "departure and return." The approach here elucidates the "idea" of Op. 34, in which the large-scale formal organization unfolds through contextually emphasized tonal relations. This study also explores Schoenberg's concept of the multi-dimensional presentation of a musical idea. Even though Schoenberg's discussion of musical coherence is usually limited to the immediate musical surface, I believe that he was also aware of an extended realization of foreground motives in the sense of Heinrich Schenker's "concealed motivic repetition." This analysis of Op. 34 demonstrates how the enlargement of a surface motive facilitates an understanding of the relation between the parts and the whole, which is perceived as the totality of Gedanke.
Date: May 2004
Creator: Fukuchi, Hidetoshi
Partner: UNT Libraries

Culturing Vallisneria americana for Restoration Efforts

Description: Robust Vallisneria americana was cultured for restoration purposes. Preliminary studies, with various iron treatments, were conducted to ascertain the amount of phosphorous release into the water column from sediments. There was a significant difference in the amount of phosphorous released if commercial sediment was used with a low iron amendment or without an iron amendment. The second study consisted of planting V. americana on two different sediment types while supplying half of the plants with additional CO2. Plants grown on pond sediment with additional CO2 had significantly more biomass. In the third study all plants were grown on pond sediment, and half were treated with CO2. All plants that were treated with additional CO2 had significantly more biomass than those that were aerated.
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Date: May 2004
Creator: Tanski, Erin M.
Partner: UNT Libraries

Key Components of a Comprehensive Visual Information System for College-Level Design Education Curriculum Analysis

Description: Electronic and computer technology have advanced and transformed graphic design. New technologies are forcing design educators to constantly monitor and update their programs, creating a need for a system to be adopted by college-level institutions to better investigate, evaluate and plan art and design curriculum. The author identifies metaphorical approaches to designing a two-part solution, which includes a Comprehensive Visual Information System (CVIS) and Three-Dimensional Virtual Database (3DVDb), which assign volumetric form to education components based on the form, structure and content of a discipline. Research and development of the conceptual design for the CVIS and 3DVDb are intended to aid in the development of an electronic media solution to be made accessible to students, faculty and administrators.
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Date: May 2004
Creator: Short, Scott Allen
Partner: UNT Libraries

Use of Fading Procedures and Positive Reinforcement to Increase Consumption of Non-Preferred Food in a Child with Autism

Description: Traditionally children with developmental disabilities who develop feeding issues can be at great risk for malnutrition. Failure to eat adequate amounts of food and/or insistence on eating a limited range of foods can be detrimental to a child's health and can lead to other behavioral difficulties. Feeding problems are difficult to treat because high levels of physical prompting can quickly create an aversion to eating as well as cause stress for both parents and children. Behavioral problems that range from moderate to extremely maladaptive can ensue. The question the present study addressed was whether or not a treatment package including only positive reinforcement and fading for a non-preferred food would result in independent eating of the targeted non-preferred food.
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Date: May 2004
Creator: Vorpahl, Cresse Merchant
Partner: UNT Libraries

The Effects of Parent Training on the Amount and Variety of Food Consumed By a Child with Autism.

Description: The current study assessed the effectiveness of a training package, delivered in the form of a manual, to teach a parent to increase the variety and amount of food consumed by her son. The participant was a 5-year-old boy with Pervasive Developmental Disorder and limited food consumption. A changing criterion design across two variables, variety of food and quantity of food, was used. Results were that the parent who used the manual, with limited assistance from the experimenter, did succeed in increasing food variety and quantity of target foods.
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Date: May 2004
Creator: VanKirk, Tessa Schreiber
Partner: UNT Libraries

Wild Practices: Teaching the Value of Wildness

Description: The notion of wildness as a concept that is essentially intractable to definition has profound linguistic and ethical implications for wilderness preservation and environmental education. A survey of the ways in which wilderness value is expressed through language reveals much confusion and repression regarding our understanding of the autonomy of nature. By framing discussions of wilderness through fact-driven language games, the value of the wild autonomy in nature becomes ineffable. In removing wildness from the discourse on wilderness we convert wilderness value from an intrinsic value into a distorted instrumental value. If we want to teach others that wilderness value means something more than a recreational, scientific, or economic opportunity, we need to include other ways of articulating this value in our education programs. Through linking the wildness of natural systems with the wild forms in human language games, I examine the conceptual freedom required for valuing autonomy in nature. The focus on what is required of language in expressing the intrinsic value of wilderness reveals that wilderness preservation and environmental education need complementary approaches to the current science-based frameworks, such as those used by the National Park Service. The disciplines of poetry, literature, ethics, and aesthetics offer alternative language games that allow for a more fluid, imaginative, and open-ended understanding of the autonomy of nature, and a means for articulating the value of this wildness that implies an ethical position of humility.
Date: May 2004
Creator: Lindquist, Christopher R.
Partner: UNT Libraries

Professional Widow

Description: The focus of my graduate work was to figure my way through a variety of challenges and transitions I was going through as a graduate student and simply as a person finding my way through my education to discover who I am and who I want to become. Perhaps my themes didn't focus primarily on these events in a literal sense, but I think the transitions in my artwork have become obvious through my time spent at UNT and the variations on a theme I have dealt with. All of my work deals with love, attraction, repulsion and the consequences we deal with as human beings when we make choices according to whom we choose to have relations with. It became very important for me to deal with these issues in an effort to discover what my expectations of myself as an artist and a person are.
Date: May 2004
Creator: McKinley, Katherine L.
Partner: UNT Libraries

Order effects of variability-contingent and variability-independent point delivery: Effects on operant variability and target sequence acquisition.

Description: Previous research has shown that variability is a reinforceable dimension of operant behavior. Additionally, it has been demonstrated that learning is facilitated when variability in responding is high. In this research, variability was observed within an operant composed of any sequence of six left and right key presses. Variability was either a requirement for point delivery (VAR conditions) or points were delivered independent of variability (ANY conditions). Two groups of college undergraduates experienced different orders of conditions. One group began the experiment under VAR conditions, and the variability requirement was later removed. The other group began the experiment under ANY conditions, and the variability requirement was later added. A concurrently reinforced target sequence (i.e., an always-reinforced sequence of left and right key presses) was introduced to both groups after these orders of conditions had been experienced. A variety of outcomes resulted. Subjects learned the target sequence when variability was both high and low with non-target points concurrently available. Other subjects learned the target sequence after all non-target point deliveries had been suspended. One subject failed to acquire the target sequence at all. These results were compared to previous findings and possible explanations for the discrepancies were suggested.
Date: May 2004
Creator: Lee, Coral Em
Partner: UNT Libraries

Analysis of Perceptional Differences Among Department Chairs, Faculty, and Instructors Toward the Barrier to Using Multiple Teaching Strategies in Two-Year Technical and Community College Electronics Courses

Description: The purpose of this study was to identify and analyze perceptional differences among department chairs, faculty, and instructors toward the barrier to using multiple teaching strategies in two-year technical and community college electronics courses. The literature review focused on defining multiple teaching strategies and identifying and discussing four major perceived barriers to implementing them in the electronics classroom: student, resources, classroom environmental, and teacher training/teaching technology. The targeted population consisted of 150 out of 231 electronics teaching technical and community college department chairs, faculty, and instructors throughout the state of Texas. In actuality, the targeted population's breakdown consisted of 36 full-time electronics teaching department chairs, 96 full-time electronics teaching faculty and instructors, and 18 part-time electronics teaching faculty and instructors who were actively involved in the delivery of instruction in their respective schools. Analysis of the data revealed that: (1) there are no significant differences among the perceptions of department chair people, faculty, and instructors toward the four perceived barriers to implementing multiple teaching strategies in a post-secondary electronics program; and (2) there are no significant differences in the perceptions electronics faculty members categorized by years teaching experience toward each of the four perceived barrier categories to implementing multiple teaching strategies in a post-secondary electronics program. However, further research is needed to substantiate what other barriers exist that may have an impact upon utilizing multiple teaching strategies in two-year technical and community college electronics courses.
Date: May 2004
Creator: Hutyra, Jerry Emil
Partner: UNT Libraries

A Comparison of the Status of Widows in Eighteenth-Century England and Colonial America.

Description: This thesis compares the status of upper-class widows in England to Colonial America. The common law traditions in England established dower, which was also used in the American colonies. Dower guaranteed widows the right to one-third of the land and property of her husband. Jointure was instituted in England in 1536 and enabled men to bypass dower and settle a yearly sum on a widow. The creation of jointure was able to proliferate in England due to the cash-centered economy, but jointure never manifested itself in Colonial America because of the land centered economy. These two types of inheritance form the background for the argument that upper-class women in Colonial America had more legal and economical freedoms than their brethren in England.
Date: May 2004
Creator: Jones, Sarah E.
Partner: UNT Libraries

Rachmaninoff's Rhapsody on a Theme by Paganini, Op.43; Analysis and Discourse

Description: This dissertation on Rachmaninoff's Rhapsody on a Theme by Paganini, Op.43 is divided into four parts: 1) historical background and the state of the sources, 2) analysis, 3) semantic issues related to analysis (discourse), and 4) performance and analysis. The analytical study, which constitutes the main body of this research, demonstrates how Rachmaninoff organically produces the variations in relation to the theme, designs the large-scale tonal and formal organization, and unifies the theme and variations as a whole. The selected analytical approach is linear in orientation - that is, Schenkerian. In the course of the analysis, close attention is paid to motivic detail; the analytical chapter carefully examines how the tonal structure and motivic elements in the theme are transformed, repeated, concealed, and expanded throughout the variations. As documented by a study of the manuscripts, the analysis also facilitates insight into the genesis and structure of the Rhapsody. How Rachmaninoff develops his ideas through several notebooks - including sketches and drafts - is described. Later parts of the dissertation deal with programmatic aspects of the Rhapsody. Related to the composer's significant use of the Dies Irae melody, semantic issues concerning "love and death" are taken into account and closely related to the specific structure of the piece. Rachmaninoff's symphonic poem, The Isle of the Dead, is a work which bears some intriguing resemblances to the Rhapsody in its larger structure as well as its ideology. Therefore, an interpretation of this work is provided to show the special relationship between the two pieces. The last chapter presents a discussion of two recordings of the Rhapsody by Rachmaninoff and Moiseiwitsch made in 1934 and 1938 respectively. Comparing and contrasting the different interpretations of each variation in these two historical recordings, this concluding part of the study explores ways in which analysis can …
Date: May 2004
Creator: Kang, Heejung
Partner: UNT Libraries

The significance of supportive structure in improving student achievement in knowledge of the history of the Christian church in a Kenyan Bible college.

Description: The problem of this study was to determine whether Kenyan Bible college students who receive instruction using a modified (highly structured) mastery learning model will demonstrate greater achievement in knowledge of Christian Church history as compared to Kenyan Bible college students who receive instruction using a traditional (minimally structured) non-mastery learning model. The subjects were 17 second-year Kenyan Bible college students enrolled in a course on Christian Church history, and they were randomly assigned to the two treatment conditions. The researcher served as instructor for both groups. The experimental group used a textbook, detailed syllabus, 200 page study guide (featuring an advance organizer to provide an ideational scaffolding), and a lesson-development feature (providing an enabling objective, congruent questions, and informative feedback for each lesson segment). The control group used a textbook and a less-detailed syllabus. Both groups shared the same classroom lectures, class discussions, required assignments, examinations, and review of examination items. Five tests of Christian church history were administered, including a pretest, three unit tests, and a comprehensive course examination. Test data were analyzed using a 2 x 5 (treatment x testing occasion) repeated measures analysis of variance (RM ANOVA). The percentage of students performing at mastery level (80% correct) on each test was also calculated. Results indicated that, from the second unit test to the comprehensive examination, the modified mastery learning group achieved slightly but consistently higher mean percentage correct scores than the traditional group, but there was no significant main effect for treatment. In contrast, the main effect for testing occasion did reach statistical significance. Across the five test occasions, 8% to 51% more students in the modified mastery learning group attained mastery level as compared to the traditional learning group.
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Date: May 2004
Creator: Duncan, David D.
Partner: UNT Libraries

An investigation of success metrics for the design of e-commerce Web sites.

Description: The majority of Web site design literature mainly concentrates on the technical and functional aspects of Web site design. There is a definite lack of literature, in the IS field, that concentrates on the visual and aesthetic aspects of Web design. Preliminary research into the relationship between visual design and successful electronic commerce Web sites was conducted. The emphasis of this research was to answer the following three questions. What role do visual design elements play in the success of electronic commerce Web sites? What role do visual design principles play in the success of electronic commerce Web sites? What role do the typographic variables of visual design play in the success of electronic commerce Web sites? Forty-three undergraduate students enrolled in an introductory level MIS course used a Likert-style survey instrument to evaluate aesthetic aspects of 501 electronic commerce Web pages. The instrument employed a taxonomy of visual design that focused on three dimensions: design elements, design principles, and typography. The data collected were correlated against Internet usage success metrics data provided by Nielsen/NetRatings. Results indicate that 22 of the 135 tested relationships were statistically significant. Positive relationships existed between four different aesthetic dimensions and one single success measure. The other 18 significant relationships were negatively correlated. The visual design elements of space, color as hue, and value were negatively correlated with three of the success measures. The visual design principles of contrast, emphasis radiated through contrast, and contrast shape were negatively correlated with three of the success measures. Finally, the typographic variables of placement and type size were both negatively correlated with two of the success measures. This research provides support to the importance of visual design theory in Web site design. This preliminary research should be viewed as a realization of the need for Web sites to …
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Date: May 2004
Creator: Cutshall, Robert C.
Partner: UNT Libraries

Biogeography of Montane Mammals on the Colorado Plateau and Adjacent Regions

Description: This study identifies the biogeographic factors that structure small mammal communities on mountains of the Colorado Plateau and adjacent regions. Forty six isolated ranges were characterized across a 5-state study area encompassing the Colorado Plateau, including the central high plateaus of Utah and the Basin and Range Province (i.e. the Great Basin and mountains of Arizona and New Mexico). Presence/absence data of 25 montane mammal species were used to explore the interactions between historical and ecological processes affecting local and regional diversity patterns. Multivariate analyses, such as non-metric dimensional scaling, were used to explore factors which influence community composition. Results of these analyses revealed the Colorado River as a significant biogeographic barrier that affects montane mammal community structure. MtDNA cytochrome b sequence variation was analyzed among populations of the long-tailed vole, Microtus longicaudus, sampled from five interior ranges of the Colorado Plateau- Abajo, LaSal, Henry, and Chuska Mts., and Boulder Mountain of the Aquarius Plateau-and analyzed using traditional phylogenetic approaches (parsimony and likelihood) as well as nested clade analysis. Results support previous documentation of a major east-west phylogeographic break occurring between populations southeast of the Colorado River (eastern Arizona, Colorado, Wyoming and New Mexico) and all other western populations, which include a central clade, a northwest clade, and an Alaskan island clade. Evidence also supports differentiation of a 'southern Rockies' clade and a distinct 'southwest island' clade. Populations of M. longicaudus north and west of the Colorado River (Boulder and Henry Mts.) share two haplotypes, form a well-supported subclade with populations from the Kaibab plateau, and are closely related to the Northwest clade. Past approaches to studying montane mammal communities utilizing theory based on island biogeography have overemphasized area and isolation as the only forces structuring insular communities. As a result, there has been a lack of recognition of the …
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Date: May 2004
Creator: Carr, Carla B.
Partner: UNT Libraries

Effects of Thickness and Indenter Tip Geometry in Nanoindentation of Nickel Films

Description: Nanoindentation has become a widely used technique to measure the mechanical properties of materials. Due to its capability to deform materials in micro- and nano-scale, nanoindentation has found more applications in characterizing the deformation behavior and determining the mechanical properties of thin films and coatings. This research deals with the characterization of samples received from Center for Advanced Microstructures and Devices (CAMD) and Integran Technologies Inc., Toronto, Canada and the objective of this investigation was to utilize the experimental data obtained from nanoindentation to determine the deformation behavior, mechanical properties of thin films on substrates and bulk materials, and the effect of geometrically different indenters (Berkovich, cubecorner, and conical). X-ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM) analysis were performed on these materials to determine the crystal orientation, grain size of the material, and also to measure any substrate effects like pile-up or sin-in respectively. The results indicate that indentation size effect (ISE) strongly depends on shape of the indenter and less sensitive to penetration depth where as the hardness measurements depends on shape of indenter and depth of penetration. There is a negligible strain rate dependency of hardness at deeper depths and a significant increase in the hardness due to the decrease in grain size and results also indicate that there is no significant substrate effect on thin films for 10% and 20% of film thicknesses. Nanocrystalline material could not validate a dislocation based mechanisms deformation for indentation made by cubecorner and conical indenters in depths less than 1mm.
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Date: May 2004
Creator: Parakala, Padma
Partner: UNT Libraries
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