Theses and Dissertations
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PublicationConformational analysis and molecular dynamics of mannosylated peptides( 1996)The objective of this project was to provide an insight into the conformational behavior of glycosylated peptides. The peptides that have been studied were composed of serine and threonine residues, as they form the majority of the amino acids in the GA linker region. The molecular dynamics (MD) study carried out on the serine tetramers and the threonine pentamers was of an exploratory nature. Our aim was to study and understand the behavior of mannosylated serine and threonine oligopeptides as they form the majority of the residues (28 out of 43) in the glycosylated linker of A. niger GA. These initial studies were needed to get an idea of the behavior of the mannosylated peptides in water, to get an idea of the relaxation time scales involved for the dihedral angles of interest and also to find out if the initial conformation had an effect on the final structure. We also wanted to study the effect of the presence of the mannosyl residues on the flexibility of the peptide backbone. The constrained conformational mapping study for regular tetramers and dimers of serine and threonines was aimed at providing an understanding of the conformational space available for these structures. It also attempted to show the effect of increasing peptide length on the conformational space. Regular structures that were identified from this conformational mapping as having low energy were then subjected to MD. This was an attempt to obtain a more realistic picture of the structures in their natural environment and could form the basis for extending this work to the whole linker, using preferred dihedral values as starting points to conduct dynamics.
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PublicationPerfectionism in varsity college student-athletes and college students( 1996)This study compared perfectionism as measured by the Frost Multidimensional Perfectionism Scale (MPS) of male and female general college students (n = 289) and Division I varsity student-athletes (n = 228). In addition, trait anxiety (SCAT), General Sport Orientation (GSOQ), and Reactions to Mistakes During Competition (RMDC) of athletes on interactive and coactive teams were examined. A 2 x 6 ANOVA was computed to determine the relationship between the two independent variables (student classification, gender) and the six dependent variables Overall Perfectionism (MPS), and MPS subscales Concern Over Mistakes, Personal Standards, Parental Expectations, Parental Criticism, and Doubts About Actions. A significant interaction effect (F (1, 506) = 6.00, p <. 05) was obtained for only the Parental Criticism subscale and found female athletes scoring significantly lower (p < .05) than both male athletes and female students. Significant main effect differences found athletes scoring higher than general college students on Overall Perfectionism (F (1,467) = 4.27, p < .05) and the subscales Concern Over Mistakes (F (1, 501) = 7.12, p < .05), and Personal Standards (F (1,498) = 19.1, p < .01). Significant gender differences indicated that men scored higher than women on Overall Perfectionism (F (1,468) = 9.88, p < .01), and the subscales Concern Over Mistakes (F (1, 502) = 16.9, p < .01), and Personal Standards (F (1,499) = 10.7, p < .01). Analysis of athletes by type of team (coactive n = 148, interactive n= 80) and gender on Overall Perfectionism and the MPS subscales produced no significant interaction effects or significant main effects by type of team. Significant main effects by gender, however, indicated that women athletes were significantly more 'Concerned About Mistakes" (F (1, 218) = 7.49, p < .01) and "Doubtful About Actions" (F (1,222) = 10.7, p < .01), but less affected by "Parental Criticism" (F (1, 119) = 3.93, p < .05) than male athletes. Examination of Competitive Trait Anxiety (SCAT), Sport Orientation (GSOQ) and Reactions to Mistakes (RMDC) showed no interaction effects by type of team and gender. Significant main effect differences, however, were found by team with athletes on coactive teams scoring higher on Competitive Trait Anxiety than those on interactive teams. No main effect differences were found for GSOQ or RMDC subscales by team or gender. Differences in perfectionism of male and female varsity athletes, general college students and athletes on coactive and interactive teams were discussed.
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PublicationExpression and functional analysis of D-raf in the Drosophila EGF-receptor pathway( 1996)The formation of a multicellular organism from a single cell requires that every cell "knows" what kind of cell that it is supposed to become. Signal transduction is one of the mechanisms used to assign cell fates. An outside signal is presented to the cell which turns on a particular pathway, the activation of specific target genes informs the cell of its fate. The Drosophila EGF receptor (DER) pathway is one such pathway, it instructs certain cells to become ventral ectoderm cells. Drosophila raf (D-raf) is believed to be a member of the early DER signal transduction pathway that determines ventral cell fates. The goal of this project is to study the characteristics of D-rafs regulation in the DER pathway. Wild-type and six modified forms of D-raf were tested for their activity in the DER pathway. Results were compared to D-rafs activity in the Torso pathway. Differences between the pathways may offer insight on how the same signal transduction cassette (Perrimon, 1993) can be used during different times during development to specify a diverse range of cellular fates.
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PublicationDesign and analysis of an inertial calibration Kalman filter( 1996)This thesis addresses the application of Kalman filtering to the in-flight calibration of an Inertial Navigation System (INS) using decentralized cascaded filtering. The system consists of a calibration filter receiving inertial reference data from an INS and radio measurements from an inertially aided Global Positioning System (GPS) receiver. The master GPS/INS and primary GPS filters receive inertial data from the same inertial reference system. The master calibration filter is a 14 state Kalman filter derived from error models commonly used in existing aided inertial navigation systems. The master filter errors states are position, velocity. attitude, gyro bias and accelerometer bias. The GPS primary filter chosen for this study is a 12 state Kalman filter. The primary filter error states are position. velocity, attitude, clock bias and clock drift. The study of this architecture focuses on the design of an embedded real-time Kalman filter application using standardized GPS and INS sensors not specifically designed for that purpose. The presentation of the design begins with a review of the system architecture and the operation of the sensor subsystems based on current literature. The design and implementation algorithms of the calibration filter that follows represents the core of the research performed. Unique design features resulting from the research are the use of an INS alignment and error model to derive the initial filter covariance, the characterization of the discrete prefiltered measurement data and the design features added as a result of simulation and empirical data. The covariance initialization, in particular has shown to significantly improve the transient estimation performance of the calibration filter over more traditional diagonal covariance initializations. Other design features that account for sensor peculiarities are a dynamically computed measurement screening algorithm to detect and eliminate spurious data and situation dependent measurement variance adjustments. The combination of these features improves the robustness and reliability of the calibration filter estimates.
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PublicationOnly a flesh wound: Is the perceived decline of the National Rifle Association real?( 1996)The focus of this thesis is to examine the National Rifle Association's current status in light of claims that its influence has seriously declined. I contend that, while it has suffered a series of minor setbacks in the past fifteen years, the NRA has remained a powerful lobbying force. In fact, the apparent "defeats" in Congress have been a rallying point for both the leadership and rank and file membership of the NRA. Simply put, the NRA is thriving on the conflicts it helps create.