Thesis (M.S.)--Northern Michigan University, 2007. / Bibliography: leaves 77-88.

Thesis (Ph. D.)--University of Chicago, Committee on Human Development, Dept. of Psychology, August 2002. / Includes bibliographical references. Also available on the Internet.

Thesis (M.I.T.)--The Evergreen State College, 2010. / Title from title screen (viewed 7/7/2010). Includes bibliographical references (leaves 102-107).

Syftet med denna studie var att undersöka om studenters inre och yttre motivation skiljde sig åt beroende på vilken högskoleutbildning individen har valt. Tidigare studier har visat att det finns en skillnad mellan typer av motivationsnivåer hos studenter på olika högskoleutbildningar. I studien deltog 46 studenter vid ett svenskt universitet från Musikproduktionsprogrammet och 39 studenter vid samma universitet från Civilekonomprogrammet. Resultatet visade att Civilekonomstudenterna hade signifikanta skillnader mellan motivationstyperna. Majoriteten av civilekonomstudenter skattade högre värden i yttre motivation (EM) än i inre motivation (IM). Civilekonomstudenterna visade även högre värden i yttre motivation (EM) i jämförelse med Musikproduktionsstudenterna. Värden i IM och EM var jämt fördelade hos studenter från musikproduktionsprogrammet och Amotivationen visade sig vara låg hos samtliga studenter. Deltagarnas årkurs och kön var kovariater som kontrollerades i studien. Här sågs deltagarnas årkurs och kön ha signifikanta samband med studenternas nivåer av IM och EM. Utifrån resultatet dras slutsatsen att studenter från musikproduktionsprogrammet sannolikt drivs av både personligt intresse och externa belöningar medan majoriteten av civilekonomstudenter endast tycks motiveras av externa belöningar. / The aim of this study was to investigate whether student’s intrinsic motivation (IM) and extrinsic motivation (EM) differs depending on which university program the individual has chosen. Previous studies have shown that there is a difference between the level of motivation among different college students. 46 Swedish university students from the Music Production Program and 39 Swedish students at the same university from the Civil Econom Program participated in the study. The results showed that the Civil Economic students had significant differences between motivational types. The majority of Civil economic students estimated higher values in EM compared to IM. The Civil Economic students even showed higher values in EM compared to students from the Music Production program. The values in IM and EM were equally distributed within students from the Music Production program and the Amotivation proved to be low among all students. The grade and the gender of the participants were covariates that were controlled in the study. The participants grade and gender showed to have correlations that were significant with the students’ level of IM and EM. Conclusions from the results are that students from the Music Production program are likely to have goals based on personal interest and external rewards while the majority of civil Economic students only seems to be motivated by external rewards.

M.A. / This study was conducted to ascertain whether there is a significant relationship between an internal locus of control orientation and elite sport performance. The question can be asked if Springbok athletes have a more internal locus of control orientation than provincial athletes and athletes in training and whether provincial athletes have a more internal locus of control than athletes in training. The term locus of control refers to the amount of control a person believes he has over the things that happen to him. A person that regards himself as someone with control over his environment and circumstances is termed a person with a internal locus of control. What happens to him and the reward he gets is dependent on his own behaviour. There are persons, on the other hand, that believe that what happens to them in their sport careers is the result of external circumstances: luck, chance or what others do to them. These persons believe that they do not have any control over what happens to them and therefore are called persons with an external locus of control. It is believed that locus of control can influence performance positively or negatively. This study tries to give answers on whether or not elite athletes have an internal locus of control. Sixty athlete's of age 16 and older were selected and divided into three groups. The first group are athletes that compete on international level, while the second group consists of athletes that compete on provincial level. The third group consists of athletes that are in training and represent athletes that perform well on school-level as well as members of sport clubs. The instrument used to test the athletes was the Internal-External Locus of Control Scale of J.B. Rotter (1966). The results confirms that elite athletes operate within an internal locus of control framework. Although not statistically significant, it seems as if athletes that compete on international level function more in an internal locus of control framework. It appears as if there is a certain interaction between top level performers and an internal locus of control.

The effect of pH, temperature, and ionic strength on the molecular conformation of five industrial polyacrylamide-based flocculants was investigated by determining intrinsic viscosities on dilute flocculant solutions. The Fedors equation was found to be most suitable for all flocculants for determining the intrinsic viscosity. The results indicated that the flocculants are fully extended in distilled water at natural pH and at 25°C as evidenced by the high intrinsic viscosities. The data pointed to the strong dependence of the intrinsic viscosity on the presence of salts as a result of the shielding of negatively charged carboxylate groups by the counterions. At a constant ionic strength of 0.01M NaCl, the flocculants assumed a coiled conformation, and further coiling was observed in the presence of small quantities of calcium chloride. CaC1₂ (0.001 mo1/L) There was a decrease in intrinsic viscosities at high pH (~8.5 and 10.5) that was merely attributed to an increase in ionic strength with the increase in concentration of Na⁺ at high pH. Intrinsic viscosity measurements at higher temperatures (35°C and 50°C) showed a small effect of temperature on the conformation of the flocculants. Higher temperature, however, seemed to accelerate the aging of the flocculant solutions. The degrees of anionicity of the flocculants were found to be in the range 1.5% to 50%, as determined through chemical analysis. It was established that determination of total organic carbon content and sodium assays is an accurate way of obtaining the degrees of anionicity of industrial flocculants. The solution stability of the flocculants in distilled water and in 0.01M NaCl was investigated over a period of three days. The reduced viscosities of the anionic flocculant in distilled water steadily decreased. The decrease was more dramatic at high temperature (50°C) than at room temperature, but no viscosity loss was observed in the presence of NaCl. The viscosity of the nonionic flocculant was stable in both distilled water and NaCl. The viscosity loss with time in the case of the anionic flocculant can be correlated with the hydrolysis of the weakly acidic carboxylate (C00⁻) groups to release OH⁻ ions and simultaneous association into uncharged carboxylic (C00H) groups that promote coiling of polyacrylamide. This effect is therefore very similar to the earlier-mentioned effect of sodium chloride. / Applied Science, Faculty of / Mining Engineering, Keevil Institute of / Graduate

Mammals are constantly challenged by numerous pathogens that pose a threat to their health. Upon infection, retroviruses quickly integrate their genome into that of their host thereby permanently modifying it. Protein members of the APOBEC3 (A3) family exhibit cytidine deaminase activity that specifically acts on single-stranded DNA to deaminate deoxycytidine bases into deoxyuridines. This process is potentially mutagenic because uracil directs the insertion of adenine on the opposite DNA strand. High levels of mutations induced by A3 proteins in the retroviral genome ultimately inactivate progeny viruses. However, under conditions where low levels of A3 proteins are present, sub-lethal mutagenesis can occur and is generally believed to be beneficial for the virus. Powerful and affordable techniques designed to detect rare deamination events generated by these deaminases along the full length of retroviral genomes are therefore essential. Through the course of my studies, I developed such a new tool that I called HyperHRM which was instrumental to my project’s success. In addition to the antiretroviral affects of their catalytic activity, some members of the A3 family have the ability to hinder reverse transcription independently of their enzymatic properties. Yet, the details underlying the deamination-independent restriction by the proteins remain unclear. Through my work, I have advanced our current understanding of this elusive process by defining the essential role for RNA-binding in the inhibition of the early steps of infection by APOBEC3G (A3G). I also demonstrate that the ability to bind RNA is important for the selection of DNA dinucleotides targeted for deamination by A3 enzymes. Based on the premise that the DNA context for deamination may alter viral fitness in various ways, I then investigated the gene inactivation potency of different A3 based on their preferred DNA substrate. My experiments showed that mutations introduced in a 5'CC context by A3G are much more lethal for the virus because of the high frequency of termination codons that are generated. I therefore clearly established that deamination target specificity has a strong influence on the overall restriction potency of A3 proteins and demonstrated that such specificity was linked to the ability of A3 proteins to bind RNA. Finally, in addition to retroviruses, mobile elements such as retrotransposons can also lead to genomic instability if not properly controlled. The A3 protein family has been shown to play a crucial role in the restriction of these elements through a mechanism that is not believed to require the enzymatic activity of the proteins, although the details of the restriction mechanism are not yet understood. Here, I provide molecular insights on the potential mechanism of retrotransposon restriction by showing that the RNA-binding properties of the enzymes are not involved in the restriction of L1 retrotransposition. A complete elucidation of the modes of restriction employed by the A3 could lead to the development of a new generation of antiretroviral drugs. Overall, my research has led to the design of a new research tool to detect and quantify A3-induced mutations in retroviruses, but more importantly, it has enabled a better understanding of how the RNA-binding abilities of A3 proteins play an essential role in the overall restriction potency of retroviruses and retrotransposons.

Magister Artium (Social Work) - MA(SW) / Learner and teacher motivation are vital to the study of learner retention or dropout rates in schools. Together with self-efficacy of both teachers and learners, its effect on learner retention rates in South African secondary schools can no longer be ignored. The aim of this research was to examine the relationships of learner and teacher motivation and self-efficacy with learners’ intention to drop out of high school. The Self-Determination Theory (SDT) and Bandura’s Theory of Self-efficacy were adopted to explain the relationship between studied variables. A quantitative methodology was used with a cross-sectional comparative design. The sample consisted of 625 learners and 111 teachers from 5 randomly selected high schools in the Metro North (from 43 government high schools) and 5 randomly selected schools in Metro East (from 42 government high schools) Education Districts in the Western Cape. Fifty percent of the schools were considered low income schools based on the school fees requirement. The data were collected using self-report questionnaires consisting of four sections, Demographic Information, the Motivational Index, Self-efficacy and Dropout Perceptions. The data were analysed with the Statistical Package for Social Sciences (SPSS V23). The current study found no significant relationships between teacher and learner motivation and self-efficacy. However, there was a significant negative relationship between teacher self-efficacy and learners’ intention to drop out of school. There was also a significant positive relationship between learner motivation and learners’ intention to drop out of school. Further research should be conducted to establish the reasons why there are negative relationships between teacher self-efficacy and learner self- efficacy. Also why a large number of learners, especially those from low socio-economic schools, seem more motivated to leave school than to persist. A further investigation is also required into the predictive factors which lead to learner vulnerability to drop out of school.

The objective of this study was to determine how neurons within the right atrial ganglionated plexus (RAGP) and posterior atrial ganglionated plexus (PAGP) interact to modulate right atrial chronotropic, dromotropic, and inotropic function, particularly with respect to their extracardiac vagal and sympathetic efferent neuronal inputs. Surgical ablation of the PAGP (PAGPx) attenuated vagally mediated bradycardia by 26%; it reduced heart rate slowing evoked by vagal stimulation superimposed on sympathetically mediated tachycardia by 36%. RAGP ablation (RAGPx) eliminated vagally mediated bradycardia, while retaining the vagally induced suppression of sympathetic-mediated tachycardia (-83%). After combined RAGPx and PAGPx, vagal stimulation still reduced sympathetic-mediated tachycardia (-47%). After RAGPx alone and after PAGPx alone, stimulation of the vagi still produced negative dromotropic effects, although these changes were attenuated compared with the intact state. Negative dromotropic responses to vagal stimulation were further attenuated after combined ablation, but parasympathetic inhibition of atrioventricular nodal conduction was still demonstrable in most animals. Finally, neither RAGPx nor PAGPx altered autonomic regulation of right atrial inotropic function. These data indicate that multiple aggregates of neurons within the intrinsic cardiac nervous system are involved in sinoatrial nodal regulation. Whereas parasympathetic efferent neurons regulating the right atrium, including the sinoatrial node, are primarily located within the RAGP, prejunctional parasympathetic-sympathetic interactions regulating right atrial function also involve neurons within the PAGP.

All twenty amino acids did not appear simultaneously in nature. Instead some of them appeared early, while others were added into the genetic code later. The amino acids that were formed by Miller (1953) are suggested to have appeared early in evolutionary history, and the amino acids associated with codon capture developed late in the course of evolution. The chronological order of appearance of the amino acids proposed by Trifonov (2000) was G/A, V/D, P, S, E/L, T, R, N, K, Q, I, C, H, F, M, Y, W. According to Romero et al. (1997) amino acids G, D, E, P and S are disorder-promoting residues and C, F, W and Y are order-promoting residues this means that the early or the ancient amino acids were disorder promoting and the order promoting residues came late into the genetic code. These observations led to the hypothesis that the first proteins, which were comprised of the early amino acids only, were disordered, and, furthermore, that the appearance of the late amino acids and the appearance of the structural proteins were concurrent. Software developed by Brooks et al. (2004) to find the amino acid composition of the LUA (Last Universal Ancestor) was used to test this hypothesis. For this work, the Clusters of Orhtologous Groups of proteins (65 COGs) were split into enzymes and non-enzymes. It was found that intrinsic disorder was abundant in both the groups of proteins, with non enzymes being much more disorder than enzymes. Further analysis was done to check for the frequency of the modern amino acids C, F, W, and Y in the Protein data bank (PDB) and Swissprot.