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A Different Drummer: A Chamber Opera

Description: A Different Drummer is a chamber opera adaptation of Donald Davis's story "A Different Drummer" from his collection Listening for the Crack of Dawn, published by August House. The opera lasts about seventy minutes, and calls for a cast of three and an orchestra of sixteen players. It contains a prologue, epilogue and four scenes in a single act. The score is prefaced by a paper describing the musical strategies employed in setting the story as an opera. Three chapters describe the adaptation from short story to opera, the essential musical elements, and details of the application of the musical elements in each scene of the opera. The libretto is presented in the fourth chapter.
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Date: May 1999
Creator: Friedman, Arnold Jacob

Paintings and Palaces, or the Lament of the Burger Flipper

Description: The opera is scored for chamber orchestra consisting of one oboe, two Bb clarinets, two horns in F, one trumpet in C, one tenor trombone, two percussionists (playing snare drum, bass drum, tambourine, wood block, triangle, suspended cymbal, crash cymbal, agogo bells, cow bell, brake drum, metal whistle, whip, large gong, Glockenspiel, chimes, timpani in F (low) and C), eight or more violins in two parts, six or more violas in two parts, and eight or more cellos in two parts. The characters are Alejandro Jiminez, a dramatic tenor; the Manager of Burger Palace, a baritone; the Suits 1/Fast Food Workers, a choir (SATB) and the Suits 2/Customers, a second choir (SATB), each ideally consisting of eight vocalists for a total of sixteen; the Daydream Figures, which are mimed parts; the Man with Gun, which is a spoken part. The opera, in one act consisting of six scenes and an interlude, is based on a libretto by the composer. There is only one scene change: from an essentially empty stage to a fast food restaurant in Scene 4. The length of the work is approximately sixty to sixty-five minutes.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: May 1999
Creator: Salfen, Kevin McGregor

Current and Future Trends in Computer Use in Elementary School Settings

Description: The study examined current and future trends in computer use in elementary school settings. A survey instrument was developed and validated for distribution to a random sample of 200 technology coordinators in the public school districts in the state of Texas from whom 95 responses were received. The survey instrument was used to obtain information about five areas of computer use in elementary schools. These areas are: physical configurations, instructional uses, implementation issues, training and staff development, and Internet use. The study found that all public school districts that participated in the study have acquired computer hardware in their elementary schools. In addition, some other advanced computer technology components are starting to be found in elementary schools, such as teacher workstations, CD-ROM, interactive video, computer multimedia, LCD panels, and laser printers. Respondents reported that elementary school teachers in their districts have incorporated computers into their classrooms as an instructional tool and many changes have occurred in teachers’ teaching styles due to computers. However, there are some problems that hinder the effective use of computers. The major problem is lack of training. A high percentage of respondents, 81.3%, indicated that the majority of their elementary school teachers had completed less than 30 hours of technology related professional development. Another problem was lack of funding which prevents most school districts from acquiring computer hardware and software. Currently, elementary schools in 87% of districts that participated in the study are connected to the Internet and the plan is that by the year 2001 all elementary schools will be connected.
Date: August 1999
Creator: Al-Awidi, Hamed M.

Vicarious Traumatization, Secondary Traumatic Stress, and Burnout in Sexual Assault and Domestic Violence Agency Staff and Volunteers

Description: Two constructs, vicarious trauma (VT) and secondary traumatic stress (STS), describe therapists’ reactions to clients’ traumatic material. VT (TSI Belief Scale [BSL]), emphasizes cognitive belief system changes resulting from cumulative exposure to survivors. STS, (Compassion Fatigue Self-test for Psychotherapists [CFST]) combines PTSD and burnout symptomatology explaining sudden adverse reactions to survivors. Burnout (BO; Maslach Burnout Inventory [MBI]), links emotional exhaustion, depersonalization, and deficient personal accomplishment to inadequate institutional supports in interpersonally demanding work. This study investigated BSL and CFST validity, counselor trauma history, and client exposure-related VT, STS, and BO in 105 trauma counselors. Results demonstrate concurrent validity between BSL and CFST; other results dispute adequate validity. BO, and client exposure were related. Traumatized counselors scored higher than non-traumatized counselors on CFST, BSL, and SCL-90-R.
Date: August 1999
Creator: Baird, Stephanie

Affective Reactions and Psychosocial Functioning in the Course of Psycho-Educational Assessment

Description: Every day, children throughout the United States are given psychological evaluations for many different clinical and psycho-educational purposes. Very little research has attempted to investigate children's responses to the experience of having intellectual and achievement tests administered. The goal of the current research was to explore the effect a psycho-educational evaluation has on children in areas of self-concept and anxiety. Dependent variables consisted of pre- and post-test measures of anxiety and self-concept. A total of 75 children in the 4th 5th and 6th grades were recruited after referral for evaluation and possible placement in the Talented and Gifted Program or Special Education. This study employed Analysis of Variance (ANOVA), t-tests, multiple regression analysis, and correlational analysis. Findings included initial evidence that children endorsed decreased anxiety after psycho-educational assessments rather than increased anxiety, suggesting that fear of unknown situations may be more anxiety provoking than the actual situation itself, potentially beneficial findings for psychology and psychometric professionals who evaluate children daily. Students endorsement of academic self-concept significantly predicted anxiety after a psycho-educational evaluation, indicating that students who feel capable in academic areas may endorse less anxiety after an evaluation than students who do not feel academically capable. Finally, negative verbal interaction with parents significantly predicted lower general self-concept scores, providing evidence that the manner in which parents verbally relate to their children may have significant impact for the mental health of children.
Date: August 1999
Creator: Buenrostro, Martha

Work Function Study of Iridium Oxide and Molybdenum Using UPS and Simultaneous Fowler-Nordheim I-V Plots with Field Emission Energy Distributions

Description: The characterization of work functions and field emission stability for molybdenum and iridium oxide coatings was examined. Single emission tips and flat samples of molybdenum and iridium oxide were prepared for characterization. The flat samples were characterized using X-ray Photoelectron Spectroscopy and X-ray diffraction to determine elemental composition, chemical shift, and crystal structure. Flat coatings of iridium oxide were also scanned by Atomic Force Microscopy to examine topography. Work functions were characterized by Ultraviolet Photoelectron Spectroscopy from the flat samples and by Field Emission Electron Distributions from the field emission tips. Field emission characterization was conducted in a custom build analytical chamber capable of measuring Field Emission Electron Distribution and Fowler-Nordheim I-V plots simultaneously to independently evaluate geometric and work function changes. Scanning Electron Microscope pictures were taken of the emission tips before and after field emission characterization to confirm geometric changes. Measurement of emission stability and work functions were the emphasis of this research. In addition, use of iridium oxide coatings to enhance emission stability was evaluated. Molybdenum and iridium oxide, IrO2, were characterized and found to have a work function of 4.6 eV and 4.2 eV by both characterization techniques, with the molybdenum value in agreement with previous research. The analytic chamber used in the field emission analysis demonstrated the ability to independently determine the value and changes in work function and emitter geometry by simultaneous measurement of the Field Emission Energy Distribution and Fowler-Nordheim I-V plots from single emitters. Iridium oxide coating was found to enhance the stability of molybdenum emission tips with a relatively low work function of 4.2 eV and inhibited the formation of high work function molybdenum oxides. However, the method of deposition of iridium and annealing in oxygen to form iridium oxide on molybdenum emitters left rather severe cracking in the protective oxide ...
Date: August 1999
Creator: Bernhard, John Michael

Information Seeking in a Virtual Learning Environment

Description: Duplicating a time series study done by Kuhlthau and associates in 1989, this study examines the applicability of the Information Search Process (ISP) Model in the context of a virtual learning environment. This study confirms that students given an information seeking task in a virtual learning environment do exhibit the stages indicated by the ISP Model. The six-phase ISP Model is shown to be valid for describing the different stages of cognitive, affective, and physical tasks individuals progress through when facing a situation where they must search for information to complete an academic task in a virtual learning environment. The findings in this study further indicate there is no relationship between the amount of computer experience subjects possess and demonstrating the patterns of thoughts, feelings, and actions described by the ISP Model. The study demonstrates the ISP Model to be independent of the original physical library environments where the model was developed. An attempt is made to represent the ISP model in a slightly different manner that provides more of the sense of motion and interaction among the components of thoughts, feelings, and action than is currently provided for in the model. The study suggests that the development of non-self-reporting data collection techniques would be useful in complementing and furthering research to enhance and refine the representation of the ISP Model. Additionally, expanding the research to include the examination of group interaction is called for to enhance the ISP Model and develop further applications that could potentially aid educational delivery in all types of learning environments.
Date: August 1999
Creator: Byron, Suzanne M.

A Structural Equation Model of Contributing Factors to Adolescent Social Interest

Description: The focus of the present study was to test through SEM the relationships between family influences (FI) and school influences (SI) on factors hypothesized to be associated with adolescent social interest: school belonging (SB), extracurricular participation (EP), and peer/romantic involvement (PRI). The final model consisted of FI and SI that contributed to the expression of adolescent social interest. FI included parental communication and parental caring. SI consisted of teacher fairness. SB consisted of a child's self-reported feelings of belonging at school, EP included self-reported involvement in sports or academic clubs, and PRI consisted of self-reported desire for romantic involvement or desire for participation with others. The proposed model suggested that FI contributed significantly to self-reported SB, EP, and PRI. Additionally, it was hypothesized that SI would contribute significantly to SB and EP, but not to PRI. The data used in the current study were part of an existing data set collected as part of the National Longitudinal Study on Adolescent Health. The total sample size for the present study was 2,561 male and female adolescents aged 12-19 years. The data consisted of adolescent and parent self-report information. Results suggested a significant relationship between FI and self-reported SB and PRI. As expected, a significant relationship existed between SI and SB. Also as expected, no significant relationship existed between SI and PRI. Neither the relationship between FI and EP nor SI and EP were significant. When analyzed separately, a significant relationship existed between SB and PRI; however, no significant relationship was found between SB and EP. Results also indicated several of the fit indices, including the average off-diagonal absolute standardized residual, the comparative fit index (CFI), and the Bentler-Bonett non-normed fit index (BBNFI), were a low to moderate fit. However, the final model was highly skewed and the model chi-square and chi-square ...
Date: August 1999
Creator: Craig, Stephen E.

Customer Induced Uncertainty and Its Impact on Organizational Design

Description: How firms facing environmental uncertainty should organize their activities remains an important and challenging question for today's managers and organizational researchers. Proponents of contingency theory have argued that organizations must adjust their activities to fit the level of environmental uncertainty to ensure long-term survival. Although much work has been done on contingency theory, it is clear that our understanding of uncertainty is far from complete. One important aspect of today's organizations is their focus on service, mass customization, and continuous innovation. This focus often results in the customer being brought either into the organization or at least into closer contact with it. Even though the literature provides numerous evidences of the increasing customer focus, it is yet to empirically explain how the complications of customer-organizational interactions might create uncertainty for contemporary organizations. The traditional measure of uncertainty still considers customers as an environmental factor causing demand uncertainty while ignoring the complex nature of customer and organizational encounters. Seeking to further refine the concept of uncertainty and focusing on the contemporary business phenomena, this study develops measures aspects of customer induced uncertainty and examines their relationships with three organizational design variables. Specifically, this study explains the complicated nature of customer - organizational encounters that creates organizational uncertainty. Also, this study develops three operational measurement instruments for the three aspects of customer induced uncertainty. Finally, this study shows specific relationships between aspects of customer induced uncertainty and specific organizational design variables. This study conducted a mail survey of middle level managers. With a sample size of 118 the measurement instruments were shown to have validity and reliability using factor analysis and Cronbach's alpha. Regression analyses indicate the presence of specific rather than general relationship between customer induced uncertainty variables and organizational design variables. Regression results suggested that the relationships between customer induced ...
Date: August 1999
Creator: Chowdhury, Sanjib Kumar

Profile of the Youth Self-Report Among South Texas Adolescents and the Potential Relationship to Pesticide Exposure

Description: The potential for human exposure to pesticides exists particularly for agricultural workers (i.e. migrant workers) and individuals within close proximity to pesticide-sprayed crops (i.e. those living on or near agricultural farms). Children, through biology and behavior, may be more susceptible and vulnerable to exposure to pesticides than adults. The purpose of this study was to examine young populations particularly at-risk for occupational or accidental exposure to pesticides and determine associated behavioral, emotional, and physical symptoms. A total of 444 students from two South Texas school districts completed questionnaires assessing level of risk of exposure to pesticides and were categorized into at-risk and low risk categories. Physical, emotional, and behavioral symptoms were obtained using the Youth Self-Report. Children who were at-risk demonstrated significantly higher scores on the Youth Self-Report (YSR) in the areas of anxious/depressed, attention problems, social problems, somatic complaints, thought problems, withdrawal, internalizing behaviors, and total problem behaviors than children who were at lower risk of pesticide exposure. Odds ratios were obtained and suggested that children in the at-risk category were more five times more likely to score in the clinically significant range on the Attention Problems subscale, and three times more likely to score in the clinically significant range on the Internalizing behavior composite. These findings suggest that children who may be at higher risk for pesticide exposure may also be at higher risk for physical, behavioral, and emotional problems compared to children who are at lower risk. This information is intended to benefit schools and health care professionals who work with rural or migrant populations involved in the agricultural trade. Future research will be needed to assess through biomarkers the degree of measurable pesticide exposure in comparison to parent reports, teacher reports, school achievement, neuropsychological testing, and medical records.
Date: August 1999
Creator: Hagar, Kristy S.

Ethnic Identity, Gay Identity and Sexual Sensation Seeking: HIV Risk-taking Predictors Among Men of Color Who Have Sex with Men

Description: This study examined relationships among ethnic identity, gay identity, sexual sensation seeking, and HIV risk-taking behaviors among 302 men of color recruited from gay bars, bathhouses, community agencies, and the 1998 United States Conference on AIDS. The sample included 24% African American, 28% Latino, 25% Asian/ Pacific Islander, 19% Caucasian, 1% American Indian, and 3% other ethnicity. Logistic regression analysis identified sexual sensation seeking, having an undefined gay identity, being in a sexually exclusive relationship, not being HIV seronegative, and length of stay in the country (for those born overseas) as significant predictors of unprotected anal intercourse (insertive and penetrative) among men of color who have sex with men.
Date: August 1999
Creator: Géliga-Vargas, Jesús A.

Night of No Exile

Description: Night of no Exile is a collection of poems preceded by a critical article entitled "‘Exile seems both a blessing and a curse': A Blissful Reading of Li-Young Lee's Poetry." That article discusses Lee's quest to achieve communication, truth, and transcendence through poetic language and concludes that he finally reaches his goal through a leap from narrative poetry to lyricism. The "exile" alluded to in the title of the article is not only geographic, but also interioran exile due to the natural limitations of all languages, and which can be bridged only in linguistic ways. Lee's solution to that problem (lyricism) turns his poetry into what Roland Barthes would call "a text of bliss," a text that manages to deeply destabilize language, while simultaneously achieving a new kind of meaning. In the main body of the manuscript, the first section contains short love lyrics. The second section, "Night of no Exile," is an attempt at the demanding genre of the longer lyric poem. The third section uses short lyrics to explore various topics, such as discovering one's identity, friendship and solidarity between women, family history, and childhood memories. Finally, the last section includes poems, four of them longer, attempting to combine narrative and lyric impulses in a way not unlike Li-Young Lee's experimentation with those two genres.
Date: August 1999
Creator: Jones, Marie C.

Explorations with Polycarbocyclic Cage Compounds

Description: A variety of novel cage-functionalized pyridyl containing crown ethers have been prepared for use in selective alkali metal complexation studies. A highly preorganized, cage-functionalized cryptand also has been designed and has been synthesized for use as a selective Li+ complexant. The alkali metal picrate extraction profiles of these cage-functionalized crown ethers also have been studied. Novel cage-functionalized diazacrown ethers have been prepared for selective alkali metal complexation studies. Alkali metal picrate extraction experiments have been performed by using this new class of synthetic ionophores to investigate the effects of cage-annulation and the influence of N-pivot lariat sidearms upon their resulting complexation properties. Novel pyridyl containing calix[4]arene receptors were prepared. Analysis of their respective 1H NMR and 13C NMR spectra suggests that calix[4]arene moieties in the ligand occupy the cone conformation. The complexation properties of these host molecules were estimated by performing a series of alkali metal picrate extraction experiments. An optically active cage-functionalized crown ether which contains a binaphthyl moiety as the chiral unit was prepared. The ability of the resulting optically active crown ether to distinguish between enantiomers of guest ammonium ions (i.e., phenylethylamonium and phenylglycinate salts) in transport experiments was investigated. Hexacyclo[,12.05,10.05,15.010,14]hexadeca-6,8-diene-4,11-dione was prepared from hexacyclo[,9.03,7.04,14.06,15] pentadeca-10,12-diene-2,8-dione. Unanticipated but remarkable acid and base promoted rearrangements of this new cage dione to novel polycyclic systems were observed and subsequently were investigated. The structures of the new systems thereby obtained were determined unequivocally by application of X-ray crystallographic methods. It is noteworthy that the reactions reported herein each provide the corresponding rearranged product in high yield in a single synthetic step. Pi-facial and regioselectivity in the thermal Diels-Alder cycloaddition between hexacyclo[,12.05,10.05,15.010,14]hexadeca-6,8-diene- 4,11-dione and ethyl propiolate have been explored. This reaction proceeds via stereospecific approach of the dienophile toward the syn face of the diene p -system. However, [4+2]cycloaddition proceeds with ...
Date: August 1999
Creator: Chong, Hyun-Soon

Toward an Ecofeminist Environmental Jurisprudence: Nature, Law, and Gender

Description: This thesis develops a legal theory reflecting the insights of feminism and environmental philosophy. I argue that human beings are not ontologically separate, but embedded in webs of relationality with natural others. My primary purposes are to 1) delineate ways in which institutions of modernity (such as law and science) have precipitated ecosocial crisis through the attempt to dialectically enforce mastery and control over nature and women; and 2) explore alternate political forms and ontologies which challenge the classical liberalist view of the (human) individual as a radically isolated, discrete, autonomous being. My overarching theme is that law functions as a narrative that can both hinder and enhance the promotion of ecological ideas, and how ecofeminism can contribute to transformative projects of environmental philosophy and feminist law.
Date: August 1999
Creator: Mallory, Chaone

A Study of Block Scheduling and Instructional Strategies and their Influence on Algebra Achievement in Classrooms Throughout North Central Texas

Description: The purpose of this study was to evaluate the influence of block scheduling and instructional strategies on student achievement in Algebra I. The study was conducted during the 1997-98 school year. This study was comprised of two components, a quantitative study and a qualitative study. The quantitative study focused on block and traditional scheduling and the influence identified through scores on the Texas End-of-Course exam for Algebra I. The sample for this study consisted of 59 school districts from five counties in the north Texas area. The qualitative portion of this study focused on 10 classrooms, 5 block and 5 traditional, taken from the sample of 59 districts. Data for the qualitative study included questionnaires, interviews, and observations. The End-of-Course scores were analyzed using an ANOVA at the .05 level of significance, no significant difference was identified in the achievement levels of the two groups. The qualitative data was organized by categories derived from the NCTM teaching standards. Data from this portion of the study indicated that teachers in both block and traditionally scheduled classes spend their class time in a similar manner, using similar materials, and using more traditional strategies. Additional analyses of data based upon usage of the graphing calculator and manipulatives also resulted in no significant difference. Although all comparisons between block and traditional scheduling and usage or non-usage of technology and/or manipulatives resulted in no significant difference, the block groups and those using technology and/or manipulatives had higher mean scores. This indicates that allowing teachers more time to use alternative instructional strategies would benefit the student, but this will not take place without the teacher receiving training and support.
Date: August 1999
Creator: McClure, Melissa Sue

A Discrimination of Software Implementation Success Criteria

Description: Software implementation projects struggle with the delicate balance of low cost, on-time delivery and quality. The methodologies and processes used to create and maintain a quality software system are expensive to deploy and result in long development cycle-time. However, without their deployment into the software implementation life-cycle, a software system will be undependable, unsuccessful. The purpose of this research is to identify a succinct set of software implementation success criteria and assess the key independent constructs, activities, carried out to ensure a successful implementation project. The research will assess the success of a software implementation project as the dependent construct of interest and use the software process model (methodology) as the independent construct. This field research involved three phases: (1) criteria development, (2) data collection, and (3) testing of hypotheses and discriminant analysis. The first phase resulted in the development of the measurement instruments for the independent and dependent constructs. The measurement instrument for the independent construct was representative of the criteria from highly regarded software implementation process models and methodologies, e.g., ISO9000, Software Engineering Institute's Capability Maturity Model (SEI CMM). The dependent construct was developed from the categories and criteria from the Delone and McLean (1992) MIS List of Success Measures. The data collection and assessment phase employed a field survey research strategy to 80 companies involved in internal software implementation. Both successful and unsuccessful software implementation projects (identified by the Delone/McLean model) participated. Results from 165 projects were collected, 28 unsuccessful and 137 successful. The third phase used ANOVA to test the first 11 hypotheses and employed discriminant analysis for the 12th hypothesis to identify the "best set" of variables, criteria, that discriminate between successful and unsuccessful software implementation projects. Twelve discriminating variables out of 67 were identified and supported as significant discriminators between successful and unsuccessful projects. ...
Date: August 1999
Creator: Pryor, Alan N.

Exhibit Eh: Canadian Dependency, U.S. Hegemony, and the Amorphousness of English Canadian Culture

Description: This thesis begins by examining the factors that have resulted in the dependent nature of Canada's political and economic structure, and proceeds to examine how this has contributed to the cultural amorphousness of English Canadian identity. The hegemonic authority of American and trans-national interests, established and maintained in the cultural sphere through the extensive monopoly of the distribution of cultural and media products, perpetuates the amorphousness of English Canadian culture through the appropriation of Canadian space by the international image industry. Such categorization of Canadian space reflects and perpetuates the imaginary representation of Canada within the dominant ideology as an indistinct and amorphous entity, and comes to usurp the materiality that constructs the lived identities of English Canadians.
Date: August 1999
Creator: McIntosh, Andrew

Photoelectric Emission Measurements for CVD Grown Polycrystalline Diamond Films

Description: We examined CVD grown polycrystalline diamond films having different methane concentrations to detect defects and study the possible correlation between the methane concentration used during the growth process and the defect density. SEM and Raman results show that the amorphous and sp2 carbon content of the films increases with methane concentration. Furthermore, photoelectric emission from diamond is confirmed to be a two-photon process, hence the electrons are emitted from normally unoccupied states. We found that the photoelectric yield, for our samples, decreases with the increase in methane concentration. This trend can be accounted for in two different ways: either the types of defects observed in this experiment decrease in density as the methane concentration increases; or, the defect density stays the same or increases, but the increase in methane concentration leads to an increase in the electron affinity, which reduces the overall photoelectric yield.
Date: August 1999
Creator: Hassan, Tarek

Girl Power: Feminism, Girlculture and the Popular Media

Description: This project is an interrogation of three examples from recent popular culture of girlculture, specifically texts that target young female consumers: the Spice Girls, Scream and Buffy the Vampire Slayer. These examples are fundamentally different than texts from earlier female targeted generic models because they not only reflect the influence of the feminist movement, they work on feminism's behalf. The project's methodology grows out of feminist film theories and cultural studies theories. One chapter is dedicated to each text, and each reading works to reappropriate girlculture texts for a counter-hegemonic agenda by highlighting the moments when each text manages to subvert its mass mediated conservative biases.
Date: August 1999
Creator: Smith, Ashley Lorrain

The Computation of Ultrapowers by Supercompactness Measures

Description: The results from this dissertation are a computation of ultrapowers by supercompactness measures and concepts related to such measures. The second chapter gives an overview of the basic ideas required to carry out the computations. Included are preliminary ideas connected to measures, and the supercompactness measures. Order type results are also considered in this chapter. In chapter III we give an alternate characterization of 2 using the notion of iterated ordinal measures. Basic facts related to this characterization are also considered here. The remaining chapters are devoted to finding bounds fwith arguments taking place both inside and outside the ultrapowers. Conditions related to the upper bound are given in chapter VI.
Date: August 1999
Creator: Smith, John C.

Picosecond Dynamics of Free-Carrier Populations, Space-Charge Fields, and Photorefractive Nonlinearities in Zincblende Semiconductors

Description: Generally, nonlinear optics studies investigate optically-induced changes in refraction or absorption, and their application to spectroscopy or device fabrication. The photorefractive effect is a nonlinear optical effect that occurs in solids, where transport of an optically-induced free-carrier population results in an internal space-charge field, which produces an index change via the linear electrooptic effect. The photorefractive effect has been widely studied for a variety of materials and device applications, mainly because it allows large index changes to be generated with laser beams having only a few milliwatts of average power.Compound semiconductors are important photorefractive materials because they offer a near-infrared optical response, and because their carrier transport properties allow the index change to be generated quickly and efficiently. While many researchers have attempted to measure the fundamental temporal dynamics of the photorefractive effect in semiconductors using continuous-wave, nanosecond- and picosecond-pulsed laser beams, these investigations have been unsuccessful. However, studies with this goal are of clear relevance because they provide information about the fundamental physical processes that produce this effect, as well as the material's speed and efficiency limitations for device applications.In this dissertation, for the first time, we time-resolve the temporal dynamics of the photorefractive nonlinearities in two zincblende semiconductors, semi-insulating GaAs and undoped CdTe. While CdTe offers a lattice-match to the infrared material HgxCd1-xTe, semi-insulating GaAs has been widely used in optoelectronic and high-speed electronic applications. We use a novel transient-grating experimental method that allows picosecond temporal resolution and high sensitivity. Our results provide a clear and detailed picture of the picosecond photorefractive response of both materials, showing nonlinearities due to hot-carrier transport and the Dember space-charge field, and a long-lived nonlinearity that is due to the EL2 midgap species in GaAs. We numerically model our experimental results using a general set of equations that describe nonlinear diffraction and ...
Date: August 1999
Creator: Stark, Thomas S.

Syllabus for Advanced Placement Biology

Description: The purpose of this syllabus is to provide a working copy to those teachers of the advanced placement biology course taught at the high school level. Reference materials used were the Texas Education Agency ( TEA ) approved Campbell text Biology and the College Board's, Advanced Placement Biology Laboratory Manual. The syllabus is divided into major topics with outlined notes and includes laboratory exercises as recommended by the College Board. The AP biology course is intended to be equivalent to college biology. College freshman biology courses can differ among colleges and among teachers within the same college. This syllabus is intended to serve as an aid to AP teachers, to cover the topics and experiments as set out by the College Board, and to the high school student, the necessary material to successfully complete the AP examination while providing freshman biology equivalence.
Date: August 1999
Creator: Turk, Cathy Christine

Parents' Motivation in Registering their Child for Gymnastics

Description: This study examined factors that motivate parents to involve their children in organized gymnastics programs. A questionnaire based on McCullagh et al.'s (1993) study of recreational soccer players was used along with open-ended questions. The questionnaire was administered to parents of children who were involved in a private gymnastics club. Descriptive statistics of 156 surveys showed that fitness, skill development, and fun were most frequently cited reasons for parents in their decision to enroll and keep their child in gymnastics programs. Competition was the least important factor. ANOVA showed that competition and team membership factors were more important to the parents of competitive gymnasts than parents of recreational gymnasts. Coaches and youth sport program organizers could use these findings to develop and market youth activity programs.
Date: August 1999
Creator: Wald, Jennie