Guiding navigation in virtual environments (VEs) is a challenging task. A key issue in the navigation of a virtual environment is to be able to strike a balance between the user's need to explore the environment freely and the designer's need to ensure that the user experiences all the important events in the VE. This thesis reports on a study aimed at comparing the effectiveness of various navigation cues that are used to motivate users towards a specific target location. The results of this study indicate some significant differences in how users responded to the various cues.

As efforts to provide seamless transitions from high school to college grow, so do the numbers of high school students who concurrently enroll in college courses across the country. The purpose of this study was to evaluate the effectiveness of various aspects of the concurrent enrollment program at Collin County Community College District in Texas. Six research questions were designed to address student success and continuing enrollment patterns after high school graduation, as well as evaluate differences in the various models of dual credit classes offered by the college. Literature related to concurrent enrollment and dual credit programs, senior year of high school, and part-time faculty effectiveness was reviewed. Student issues addressed include: grade performance of concurrent enrollment students compared to the general college population; the percentage of concurrent enrollment students who continue at the college after high school graduation; and a comparison of continuing concurrent enrollment students with a matched sample (based on high school class rank), on the student success factors of fall-to-spring retention rates, fall-to-fall retention rates, grade point averages, and completion rates. Findings were generally positive related to the impact of concurrent enrollment on students and their subsequent success at the college. Various models of offering …

The purpose of this study was to investigate the extent of Prince George's Community College faculty knowledge of the legal issues, Section 504 of the Rehabilitation Act of 1973, The Americans With Disabilities Act of 1990, and recent court decisions, related to the provision of classroom accommodations for students with disabilities at the postsecondary level. The focus of the study was to determine if a difference existed between the knowledge of full-time and part-time faculty. Part-time faculty comprise over 50 % of the instructional staffs at most community colleges and are considered an integral part of their institutions, yet they are offered little opportunity for professional development. The variables of gender, department affiliation, teaching at more than one institution, number of years of teaching experience, number of students taught with a disability, and number of individuals known with a disability also were reviewed. Data were collected through a questionnaire distributed to 158 faculty members at the college. Twenty-nine packets were returned as undeliverable. Of the 129 deliverable packets, 57 were returned for a response rate of 44.2%. Results from the analysis of data indicated that faculty have very limited knowledge of the legal issues concerning students with disabilities. Only 26.9% …

Heavy metal bioaccumulation in aquatic organisms may occur through direct or indirect uptake routes. Research indicates that the significance of uptake route varies with contaminant and organism exposed. The relative importance of different metal sources in aquatic systems was investigated by exposing freshwater snails to dietary or dissolved sources of cadmium. Snails were exposed to control, contaminated food only, contaminated water only, and contaminated food and water treatments. During the 15-day exposure, samples were taken to determine Cd concentration in snail soft tissue, snail shell, algal food, and overlying water. Analyses of snail soft tissue and shells indicate that exposure route significantly affects Cd concentrations in the tissues. In both cases, dissolved Cd is the primary contributor to metal body burden.

This study examined the effects of a computer-mediated intervention on "at-risk" preschool students' receptive vocabulary development, computer-literacy skills, and enthusiasm for leaning. Twenty-two preschool-aged children attending an urban primary public school and participating in government subsidized school lunch program participated in the study. A pretest/posttest control-group design and case-study participant observations were used for data collection. Students were assigned to one of two treatment groups. Eleven preschool students with pretest School Readiness Composite (SRC) standard scores of 80, or below, on the Bracken Basic Concept Scale-Revised (BBCS-R), were assigned to the intervention group. Eleven pre-school students matched by age level and teacher comprised the comparison group. The intervention group received computer-mediated instruction while the comparison group received classroom teacher instruction. The first research question examined the effect of the intervention on students' receptive vocabulary analyzing groups' pretest and posttest BBCS-R School Readiness Composite mean scores. Combined analysis of a Two-Factor Repeated Measures and a Posttest only ANCOVA revealed that computer-mediated instruction was as effective as classroom teacher instruction in helping "at-risk" students acquire readiness receptive vocabulary. The second research question examined the effect of the intervention on "at-risk" student's computer-literacy skills analyzing participants pretest and posttest mean scores on the …

World War II represented a watershed event in the history of the United States and affected political, economic, and social systems at all levels. In particular, the war unleashed forces that caused rapid industrialization, immigration, and urbanization in two regions, the South and the West. This study examines one community's place in that experience as those forces forever altered the city of Fort Worth, Texas. Prior to World War II, Fort Worth's economy revolved around cattle, food-processing, and oil, industries that depended largely on an unskilled labor force. The Fort Worth Stockyards laid claim to the single largest workforce in the city, while manufacturing lagged far behind. After an aggressive campaign waged by city civic and business leaders, Fort Worth acquired a Consolidated Aircraft Corporation assembly plant in early 1941. The presence of that facility initiated an economic transformation that resulted in a major shift away from agriculture and toward manufacturing, particularly the aviation industry. The Consolidated plant sparked industrial development, triggered an influx of newcomers, trained a skilled workforce, and stimulated an economic recovery that lifted the city out of the Depression-era doldrums. When hostilities ended and the United States entered the Cold War period, Consolidated and the adjacent …

The purpose of this study was to analyze the impact of alternative school intervention on subsequent student performance. The literature review examined the history and development of alternative schools, the legislation pertaining to alternative schools, and related studies. The population consisted of students placed in the discipline alternative education program (DAEP) of an alternative school located in a large suburban school district in north Texas. Students placed in DAEP in the spring semester of 2001 in grades 7, 8, 9, and 10 were included in the sample. Data on student success was gathered for the one semester prior to placement (pre-intervention) and for the two semesters after placement (post-intervention). Student success was measured in terms of course grade averages and attendance. The student sample was divided into the following subgroups: grade level, sex, ethnicity, and qualification for the school meal program. The students' grade averages were compared within the subgroups utilizing a one-way analysis of variance (ANOVA). Tukey's post hoc comparison was utilized on the groups when ANOVA was found to be significant. The students' attendance was analyzed by comparing the proportion of days attended in each of the three semesters included in the study. A normal test of two …

Geometric packing problems are NP-complete problems that arise in VLSI design. In this thesis, we present two novel algorithms using dynamic programming to compute exactly the maximum number of k x k squares of unit size that can be packed without overlap into a given n x m grid. The first algorithm was implemented and ran successfully on problems of large input up to 1,000,000 nodes for different values. A heuristic based on the second algorithm is implemented. This heuristic is fast in practice, but may not always be giving optimal times in theory. However, over a wide range of random data this version of the algorithm is giving very good solutions very fast and runs on problems of up to 100,000,000 nodes in a grid and different ranges for the variables. It is also shown that this version of algorithm is clearly superior to the first algorithm and has shown to be very efficient in practice.

Invasive pulmonary aspergillosis is a life-threatening fungal infection commonly observed in immunocompromised patients and has a mortality rate approaching 100% once the disease is disseminated. Aspergillus fumigatus is the most common pathogen. Early diagnosis improves the prognosis but is very difficult since most signs and symptoms are nonspecific. Antifungal therapy, usually based on sterol biosynthesis inhibitors, is also of limited efficacy. In my attempts to discover a diagnostic sterol marker for aspergillosis, I observed that A. fumigatus incorporates large amounts of cholesterol from serum-containing medium. This observation suggested the hypothesis that exogenous cholesterol from the host can be imported by A. fumigatus and used as a substitute for ergosterol in the cell membrane. This proposed mechanism would reduce the efficacy of antifungal drugs that act as sterol biosynthesis inhibitors. Experiments to test this hypothesis were designed to determine the effects of serum-free and serum-containing medium on growth of A. fumigatus in the presence and absence of azole antifungal agents. The results showed a marked increase in growth in the presence of human serum. Cultures in media containing cholesterol but no serum also showed enhanced growth, a result indicating that a non-cholesterol component of serum is not primarily responsible for the …

This thesis is the about the life of Rudder. The emphasis of this work, however, is that Rudder was successful primarily because of his character and leadership style. Much of the study was drawn from primary sources. Secondary sources were also consulted. This thesis opens with a brief Introduction, which discusses the need for this work. Chapter 1 discusses Rudder's life prior to WW II, emphasizing particular characteristics that benefited his leadership ability. Chapter 2 examines the 2nd Ranger Battalion's transformation under Rudder's leadership and guidance. Chapter 3 chronicles the 2nd Ranger Battalion's assault on the Pointe du Hoc battery, ending in December 1944, when Col. Rudder was reassigned to the 109th Infantry Regiment. Moreover, the controversy surrounding the Ranger's mission is also examined in this chapter. Chapter 4 describes Col. Rudder's leadership with the 109th in the Battle of the Bulge. A chapter accounting Rudder's political career and leadership follows. Chapter 6 examines his term as chancellor and president of the Texas A&M University system, until his death in 1970, and the major institutional changes that he enacted during his tenure, which resulted in A&M becoming the respected research university it is today. This significance and recapitulation of Rudder's …

Voluntary turnover has become a problem for many organizations in today's society. The cost of this turnover reaches beyond organizational impact, but also affects the employees themselves. For this reason, there has been a plethora of research conducted by both academicians and practitioners on the causes and consequences of voluntary turnover. The purpose of this study is to test the validity and generalizability of the job embeddedness model of voluntary turnover to the information technology (IT) industry. The IT field has been plagued with high turnover rates in recent years. In this study, the job embeddedness model (Mitchell et al., 2001) is applied to a population sample consisting of health care information technology employees.

For Muscogee Creek poet Joy Harjo, poetry is a real world force that can empower the reader by utilizing mythic memory, recovery of history, and a spiral journey to regain communal identity. Her poetic career transforms from early lyric poems to a hybridized form of prosody, prose, and myth to accommodate and to reflect Harjo's concerns as they progress from personal, to tribal, and then to global. She often employs a witnessing strategy to combat the trauma caused by racism in order to create the possibility for renewal and healing. Furthermore, Harjo's poetry combats forces that seek to define Native American existence negatively. To date, Harjo's poetic works create a myth that will refocus humanity's attention on the way in which historical meaning is produced and the way difference is encountered. In an effort to revise the dominant stories told about Indians, Harjo privileges the idea that Native Americans are present and human, and it is this sense of humanity that pervades her poetry. Sequentially, Joy Harjo's volumes of poetry-She Had Some Horses (1983), In Mad Love and War (1990), and The Woman Who Fell from the Sky (1994)-create a regenerative cycle that combats the effects of oppressive history and …

Development and population are rapidly increasing in urbanizing areas of North Texas and so is the need to understand changes in storm water runoff flow and its contamination by nutrients, sediment, pesticides and other toxicants. This study contributes to this understanding and has two primary components: first, development of a graphical user interface for a geographic information system and storm water management database, and second, performing a two-scale hydrological modeling approach (the US Corp of Engineers HEC-HMS model and the US Environmental Protection Agency SWMM model). Both primary components are used together as a toolkit to support the storm water management program of the City of Carrollton, located in North Texas. By focusing limited city resources, the toolkit helps storm water managers in the process of compliance with federal regulations, especially the National Pollution Discharge Elimination System permit, and provides guidance for reporting, planning and investigation. A planning example was conducted by modeling potential changes in storm water quality due to projections of land use based on the City of Carrollton's Comprehensive Plan. An additional component of this study is the evaluation of future changes in surface water quantity and quality in the North Central Texas area, specifically in a …

On-line Analytical Processing (OLAP) is a very interesting platform to provide analytical power to the data present in the database. This paper discusses the system designed which handles integration of data from two remote legacy reservation systems to merge as one Integrated database server and also the design of an OLAP database and building an OLAP cube for the data warehousing. OLAP cube is useful for analysis of data and also for making various business decisions. The Data Transformation Services (DTS) in the Microsoft® SQL Server 2000 is used to integrate as a package the collection of data and also for refreshing data in the databases. On-line Analytical Processing (OLAP) cube is designed using Microsoft® Analysis Server.

The body of work created during this exploration indicates that painting approach can actively integrate with the clay element. The main point is the surface manipulation during this process. There are four factors relate to this manipulation: timing, action, style, and size. Overall, the painting approach can be modified to create a truly active relationship with clay element. The final touch by the fire and glazing techniques reflect paintings approach may be used in a variety way to decorate the clay element without any limits. Moreover, the painting approach need not be subordinate to the clay element. It can be used not only to complement the clay, but also to enhance any given clay pieces no matter what the shape is.

Intimate partner violence is endemic in the United States. According to the American Medical Association (1992), one-fifth to one-third of women will sustain violence from a partner or ex-partner in their lifetime. The relevant literature was organized by ICD-9-CM categories. This study examined the health consequences of partner abuse in a sample of community women using a sample consisting of 564 women in three ethnic groups. Because prior research has failed to account for variations by type of abuse on health consequences, this study assessed psychological abuse, violence and sexual aggression by women's partners. To determine whether or not different types of abuse had an effect on women's health, hierarchical regression analyses were conducted. The regression equations were calculated for women within each ethnic group to facilitate identification of similarities and differences and to control for ethnic differences in risk for specific diseases. The results were consistent with past research on health consequences of abuse and extended the prior literature by showing that psychological abuse had a pervasive effect on health conditions, distress and use of health care resources. Additionally, ethnic differences emerged. As expected, ethnicity appeared to function as a moderator. Clinical implications and recommendations are made for future …

With the growing popularity of e-commerce applications that use software agents, the protection of mobile agent data has become imperative. To that end, the performance of four methods that protect the data integrity of mobile agents is evaluated. The methods investigated include existing approaches known as the Partial Result Authentication Codes, Hash Chaining, and Set Authentication Code methods, and a technique of our own design, called the Modified Set Authentication Code method, which addresses the limitations of the Set Authentication Code method. The experiments were run using the DADS agent system (developed at the Network Research Laboratory at UNT), for which a Data Integrity Module was designed. The experimental results show that our Modified Set Authentication Code technique performed comparably to the Set Authentication Code method.

There are two major, well-known operas based on plays of Tennessee Williams. He refused many times throughout his life to give permission for his play, A Streetcar Named Desire, to be set as an opera. It was not until the 1960s that he granted permission for Lee Hoiby to choose any of his plays as a basis for a new opera. Hoiby chose Summer and Smoke, a play which was written at approximately the same time as Streetcar. Lanford Wilson created the libretto for the opera which was given its premier in 1971 by the St. Paul Opera Association. In 1994 representatives of the Williams estate granted permission to the San Francisco Opera to commission an opera based on A Streetcar Named Desire. With a libretto by Philip Littell, the opera was composed by André Previn and given its premier in 1998. These two plays share common themes, character types, character relationships, and literary symbols due in part to the autobiographical nature of Williams's writings. The plays exhibit a cinematic nature and possess common dramatic elements such as the symbolic use of sets, props, and musical leitmotifs as a result of his attempts to create a new "plastic" style of …

The intent of the study was to ascertain the importance faculty at Historically Black Private Colleges and Universities in Texas place upon academic activities of research, teaching and service. A survey of faculty at 4 historically black private colleges and universities in Texas (HBCUs) was conducted to collect data from 158 faculty members; 107 usable questionnaires were returned. A response rate of 67.7 percent was achieved. The pattern that emerged from the data indicates the HBCU faculty in this study lean toward teaching and service as being a viable measure for tenure and promotion. The HBCU faculty in this study should remain cognizant that they are an intricate element within the higher education discipline. According to the perceptions of the HBCU faculty, several indicated that their college/university is important; however, they indicated that their academic discipline is less important in comparison. According to the perceptions of the HBCU faculty, many respondents indicated that their job is a source of considerable personal strain. A comparison with the findings of the 1989 Carnegie Foundation for the Advancement of Teaching reveals more similarities than differences.

This dissertation examines the political writings and speeches of Baldur von Schirach, a leading figure of the National Socialist German Worker's Party, and the means by which he chose to transmit his beliefs in totalitarianism, racism, and militarism. Schirach's activities serve as a case study of the Third Reich's artistic and cultural programs and the means by which these programs served as conduits for propaganda and public education. Throughout his career as the leader of the National Socialist Student's League, Reich Youth Leader, and Gauleiter of Vienna, Schirach promulgated a political theory which interpreted the rise of the Third Reich as an expression of an innately superior German culture. He put this theory forth through the use of artistic means, including his own poetry and prose, and theoretical exegeses of artistic and literary works that explained them within a fascist, totalitarian idiom. The dissertation discusses Schirach's personal adherence to Nazism and its roots; the ways in which he interpreted fascist philosophical tenets, symbols, messages, and archetypes; his concepts of youth and adult education; his attempts to mold the artistic community of Vienna into an aesthetically progressive, yet politically coherent, means of propaganda; and his role in the destruction of the …

This research examined the reasons for participation in continuing professional education (CPE) and the predictive relationship of those motivational reasons to the perceived leadership effectiveness of first-line supervisors. For this study, 105 first-line supervisors were surveyed from four electric utility companies. Input was also collected from each supervisor's subordinate employees. Using the five motivational reasons for participation, collected via the Participation Reasons Scale and the effectiveness score collected using the Leader Behavior Analysis II®, regression techniques were used to asses the data. The five participation reasons of the PRS were regressed individually against the effectiveness scores to determine the extent to which leader effectiveness could be predicted by the participation reasons. In each case, the null hypothesis failed to be rejected. Regression of the five PRS reasons collectively on leader effectiveness also failed to reject the null, producing a p value of .800 and an R2 value of .023. An "all possible subsets" regression was conducted to determine whether a smaller subset of the five predictor variables might improve the predictive value of the participation reasons. No subset improved the predictive value. This study concludes that motivation to participate in CPE does not predict leader effectiveness. Thus, training organizations do …

American composer Roger Reynolds was born on July 18, 1934, in Detroit, Michigan. At age 14, he determined to study piano after hearing a recording of Chopin's Polonaise in A-flat major, Opus 53 played by Vladimir Horowitz. Even though his piano teacher Kenneth Aiken recommended that he continue his study at the Curtis Institute of Music, Reynolds followed the suggestion from his parents that a musical career was not practical. After receiving a bachelor degree of engineering physics at the University of Michigan, he worked in the industry for a short period of time. In 1957, he returned to Michigan and resumed his study of music by taking a class called Composition for Non-Composers under the instruction of Ross Lee Finney. Reynolds continued his compositional study with Finney and Gerhard who were influenced by the Second Viennese School until he finished the master's degree (B.M. 1960, M.M. 1961). Variation was written under the auspices of The Banff Centre for the Arts in 1988. This piece was dedicated to Peter Serkin and premiered by Alec Karis, a faculty member at UCSD, on December 3, 1991 at Merkin Concert Hall, New York. This large-scale set of variations for piano is one of …

Finite functions (also called maps) are used to describe a number of key computations and storage mechanisms used in software and hardware interpreters. Their presence spread over various memory and speed hierarchies in hardware and through various optimization processes (algorithmic and compilation based) in software, suggests encapsulating dynamic size changes and representation optimizations in a unique abstraction to be used across traditional computation mechanisms. We developed a memory allocator for testing the finite functions. We have implemented some dynamic finite functions and performed certain experiments to see the performance speed of these finite functions. We have developed some simple but powerful application programming interfaces (API) for these finite functions.

The regulation of pyrimidine biosynthesis was studied in Pseudomonas putida. The biosynthetic and salvage pathways provide pyrimidine nucleotides for RNA, DNA, cell membrane and cell wall biosynthesis. Pyrimidine metabolism is intensely studied because many of its enzymes are targets for chemotheraphy. Four aspects of pyrimidine regulation are described in this dissertation. Chapter I compares the salvage pathways of Escherichia coli and P. putida. Surprisingly, P. putida lacks several salvage enzymes including nucleoside kinases, uridine phosphorylase and cytidine deaminase. Without a functional nucleoside kinase, it was impossible to feed exogenous uridine to P. putida. To obviate this problem, uridine kinase was transferred to P. putida from E. coli and shown to function in this heterologous host. Chapter II details the enzymology of Pseudomonas aspartate transcarbamoylase (ATCase), its allosteric regulation and how it is assembled. The E. coli ATCase is a dodecamer of two different polypeptides, encoded by pyrBI. Six regulatory (PyrI) and six catalytic (PyrB) polypeptides assemble from two preformed trimers (B3) and three preformed regulatory dimers (I2) in the conserved 2B3:3I2 molecular structure. The Pseudomonas ATCase also assembles from two different polypeptides encoded by pyrBC'. However, a PyrB polypeptide combines with a PyrC. polypeptide to form a PyrB:PyrC. protomer; six …