995 resultados para Thesis (M.Sc.)--Brock University, 2003.


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The purpose of this correlational study was to investigate the relationship between the degree of self-directed learning readiness and stress for level one nursing students and level two nursing students. One hundred female nursing students participated in the study who were attending an Ontario Community College. Data were collected from the main nursing campus and the satellite nursing campus using the random sample method. Instruments used were said to be valid and reliable for testing self-directed learning readiness and stress respectively. Data were analyzed using frequency response to each item, means and standard deviation, and the Pearson product correlation between selfdirected learning readiness and stress. The results of the study show that there is a difference in the relationship between the degree of self-directed learning readiness and stress between the level one nursing students and the level two nursing students. Such results will be of particular interest to nursing instructors and administrators when planning for delivery of programs to such students.

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The main purpose of this thesis is to study properties of La2/3Cai/3Mn03, both polycrystalline ceramics and thin films. This material has striking related electrical and magnetic properties. Thin films show colossal negative magnetoresistance (CMR) near transition from an insulating to a metallic state accompanied closely by transition from a paramagnetic to a ferromagnetic state. The double exchange mechanism (DE) and the Jahn-Teller deformations play an important role in CMR effect. Applied pressure has a very similar effect as does an applied magnetic field, except, at low temperatures (T

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The monoconjugates of phenolic acids (i.e. coumaric acid) with polyamines such as spermidine and spermine are strikingly similar to some toxins from spiders and predatory wasps. Many plants contain phenolic acid polyamine conjugates and there is some reliable information supporting their roles as plant defense chemicals. Eleven monoacylated compounds of diamines, triamines, tetraamines and oxa-polyamine amines were prepared in three to seven steps: 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 and 32. The synthesis proceeds through stepwise construction of the polyamine backbone (as in 62 and 72), followed by protection and deprotection steps of the amino functions. Desymmetrization of readily available and prepared symmetrical polyamines is a key step in the synthesis. The protecting groups employed were tert-butoxycarbonyl (BOC) and trifluoroacetyl (TFA) group which were removed under different conditions: acid and base respectively. Deprotection and refunctionalization of the polyamine reagent demonstrated the versatility of these systems for N-acylation.

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Interest in mixed-valent perovskite manganese oxides of La\-xAxMnO^ (v4-divalent alkaline earth Ca, Sr or Ba), whose unusual properties were discovered nearly a half century ago, has recently been revived. The discovery of the colossal magnetoresistance and pressure effects introduced new questions concerning the complex interplay between lattice structure, magnetism and transport in doped perovskite manganites. In this study, we report our experimental investigations of pressure and magnetic field dependencies of La-i/sCai/sMnOs (LCMO) epitaxial films with various thickness on SrTiO$ substrate. An analysis of film thickness dependency of the resistivity of LCMO epitaxial films under pressure and magnetic field has been performed by taking into account substrate contributions. This verifies the correlation of lattice distortion with magnetic and transport properties. Strong dependencies of Mn — O — Mn bond bending and Mn — O bond stretching with pressure as well as Mn spin alignment with magnetic field, and the lattice distortion induced by the substrate are discussed.

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This study presents information gathered during personal interviews with dynamic and capable teachers in the areas of preparedness for teaching, teaching concerns, survival skills and strategies, and how these teachers support themselves and others in the teaching profession. The data are related to Purkey and Novak's work on invitational education and connections are made to Combs' perceptual orientation. Potential participants were gathered through personal recommendations from their colleagues. All teachers recommended were approached and asked for voluntary participation. Of those who agreed to participate, 6 were selected based on gender and years of experience. There was a male and female participant at each of the following career levels: early, mid, and late. The 4 major survival skills that became apparent were the ability to believe in oneself and others, to act decisively upon that belief through personal and professional goal-setting as well as accessing resources, to actively seek opportunities for interaction with other professionals, and to celebrate personal and professional successes.

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This study explored the impact of training parents and children concurrently in principled negotiation skills for the purpose of developing negotiation skills and problem solving abilities in children. A second experimental group was utilized to determine the viability of negotiation skills training of junior elementary students for the purpose of improving problem solving and conflict resolving abilities. The student population in each experimental group was trained using The Program for Young Negotiators (Curhan, 1996). A control group was also established using the remaining grade four and five students attending the participating school. These students did not receive training as part of this study. Student group distribution was as follows: Experimental group 1 (students with parent participant) consisted of 10 (5 grade five and 5 grade 4 students), Experimental group 2 students without parent participant) consisted of 48 (20 grade 4 and 28 grade 5 students), and the Control group 3 (55 grade 4 and 5 students). The impact of training was measured using the Five Factor Negotiation Scale developed for use with the Program for Young Negotiators (Curhan, 1996). This measure was employed as a pre- and post-test questionnaire to the total student population, (113 students) to determine levels of ability in each of the key elements of negotiation, personal initiative, collaboration, communication, conflict based perspective taking, and conflict resolution approach (Nakkula & Nikitopoulos, unpublished). This measure has a coefficient alpha of .75 which is acceptable for this type of affective instrument. As well, open ended ability questions designed to measure ability, knowledge, and behaviour as they relate to negotiation skill application were given to the total student population, (113 students). Finally, journals were maintained by the students in both experimental groups, and informal feedback discussions were held with students and parents participating in the study.The intent of using both qualitative and quantitative measures was to provide an overall perspective of student abilities as they related to principled negotiation skills. While the quantitative measures were from the student perspective, more qualitative information was sought from parents and teachers through informal interviews, discussions, and use of confidential feedback cards. For analysis purposes, the ability questions were randomly selected for Experimental group 2 and Control group 3 in an effort to balance the groups more equitably with Experimental group 1. The findings of this study indicate that students of the junior elementary school age can be taught how to perceive conflict in a more constructive way. However, they are not as likely to use their skills when the conflict is with a sibling as they are with a peer, a teacher, or a parent. While no statistically significant differences between mean scores for Experimental groups 1 and 2 exist some subtle differences are noted. Overall, increases in mean scores for grade 4 students exceeded the increases for grade 5 students within Experimental group 1 . The implication being that younger students benefit more from having a parent trained in principled negoUation skills than older students. The skill level of a parent in principled negotiation can not be underesUmated. Without a consistent and effective role model the likelihood of developing student skill level to a point of automaticity is greatly reduced. Enough so that perhaps the emphasis should be placed on training parents more so than the students.

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The maximum amount of ethyl carbamate (EC), a known animal carcinogen produced by the reaction of urea and ethanol, allowed in alcoholic beverages is regulated by legislation in many countries. Wine yeast produce urea by the metabolism of arginine, the predominant assimilable amino acid in must. This action is due to arginase (encoded by CARl). Regulation of CARl, and other genes in this pathway, is often attributed to a well-documented phenomenon known as nitrogen catabolite repression. The effect of the timing of di-ammonium phosphate (DAP) additions on the nitrogen utilization, regulation of CARl, and EC production was investigated. A correlation was found between the timing of DAP addition and the utilization of nitrogen. When DAP was added earlier in the fermentations, less amino nitrogen and more ammonia nitrogen was sequestered from the media by the cells. It was also seen that early DAP addition led to more total nitrogen being used, with a maximal difference of ~25% between fermentations where no DAP was added versus addition at the start of the fermentation. The effect of the timing ofDAP addition on the expression of CARJ during fermentation was analyzed via northern transfer and the relative levels of CARl expression were determined. The trends in expression can be correlated to the nitrogen data and be used to partially explain differences in EC formation between the treatments. EC was quantified at the end of fermentation by GC/MS. In Montrachet yeast, a significant positive correlation was found between the timing of DAP addition, from early to late, and the final EC concentration m the wine (r = 0.9226). In one of the fermentations, EC levels of 30.5 ppb was foimd when DAP was added at the onset of fermentation. A twofold increase (69.5 ppb) was observed when DAP was added after 75% of the sugars were metabolized. When no DAP was added, the ethyl carbamate levels are comparable at a value of 38 ppb. In contrast, the timing of DAP additions do not affect the level EC produced by the yeast ECU 18 in this manner. The study of additional yeast strains shows that the effect of DAP addition to fermentations is strain dependent. Our results reveal the potential importance of the timing of DAP addition to grape must with respect to EC production, and the regulatory effect of DAP additions on the expression of genes in the pathway for arginine metabolism in certain wine yeast strains.

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Two efficient, regio- and stereo controlled synthetic approaches to the synthesis of racemic analogs of pancratistatin have been accomplished and they serve as the model systems for the total synthesis of optically active 7-deoxy-pancratistatin. In the Diels-Alder approach, an efficient [4+2] cycloaddition of 3,4-methylenedioxyco- nitrostyrene with Danishefsky's diene to selectively form an exo-nitro adduct has been developed as the key step in the construction of the C-ring of the target molecule. In the Michael addition approach, the key step was a conjugate addition of an organic zinc-cuprate to the 3,4-methylenedioxy-(B-nitrostyrene, followed by a diastereocontroUed closure to form the cyclohexane C-ring of the target molecule via an intramolecular nitro-aldol cyclization on a neutral alumina surface. A chair-like transition state for such a cyclization has been established and such a chelation controlled transition state can be useful in the prediction of diastereoselectivity in other related 6-exo-trig nitroaldol reactions. Cyclization of the above products fi^om both approaches by using a Bischler-Napieralski type reaction afforded two lycoricidine derivatives 38 and 50 in good yields. The initial results from the above modeling studies as well as the analysis of the synthetic strategy were directed to a chiral pool approach to the total synthesis of optically active 7-deoxy-pancratistatin. Selective monsilylation and iodination of Ltartaric acid provided a chiral precursor for the proposed key Michael transformation. The outlook for the total synthesis of 7-deoxy-pancratistatin by this approach is very promising.A concise synthesis of novel designed, optically pure, Cz-symmetrical disulfonylamide chiral ligands starting from L-tartaric acid has also been achieved. This sequence employs the metallation of indole followed by Sfj2 replacement of a dimesylate as the key step. The activity for this Cz-symmetric chiral disulfonamide ligand in the catalytic enantioselective reaction has been confirmed by nucleophilic addition to benzaldehyde in the disulfonamide-Ti (0-i-Pr)4-diethylzinc system with a 48% yield and a 33% e.e. value. Such a ligand tethered with a suitable metal complex should be also applicable towards the total synthesis of 7-deoxy-pancratistatin.

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The Common Tern (Sterna hirundo) is a ground nesting colonial seabird. Terns rely primarily on small prey fishes which they obtain through plunge diving for their survival as well as the survival of their offspring during the breeding season. The zebra mussel (Dreissena polymorpha) is a small bivalve mollusk that invaded North American waters in the late 1980's. Through its suspension feeding, the zebra mussel has the ability to alter the entire aquatic ecosystem, ultimately leading to a reduction in pelagic organisms including small prey fish. The objective of the study was to determine what (if any) indirect effects the invasion of the zebra mussel has had on fish prey captured by terns. The study took place in two separate two-year periods, 1990-91 and 1995-96 on a concrete breakwall off the north shore of Lake Erie near Port Colborne, Ontario. Daily nest checks revealed clutch initiation dates, egg-laying chronology, hatching success and morphological egg characteristics (length and breadth). Behavioural observations included time each sex spent in attendance with its brood, the frequency of feeding chicks and the prey species composition and size fed to chicks as well as to females (courtship feeding). Egg sizes did not differ between study periods, nor did feeding rates to chicks, suggesting that food was not a limiting resource. Terns spent less time with their broods (more time foraging) in the 1995-96 period. However, they also had significantly larger broods and fledged more offspring. The time of each individual foraging trip decreased, suggesting that fish were easier to obtain in 1995 and 1996. Lastly, kleptoparasitism rates decreased, suggesting that the costs of foraging (time, energy) actually decreased as fewer birds adopted this strategy to compensate for what I assumed to be a lack of available food (fish). The only significant difference between the periods of 1990, 1991 and 1995, 1996 was a change in diet. Terns delivered significantly fewer rainbow smelt and more emerald shiner in 1995 and 1996. However, the average size of fish delivered did not change. Thus, there was little impact on prey captured by Common Terns in Lake Erie since the invasion of the zebra mussel.

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This study tested a model which predicted the relationship between underemployment and depressive affect as moderated by coping styles. A randomly selected community sample of 574 young adults completed a self-report employment status measure, the Underemployment Scale, the Center for Epidemiological Study Depression Scale, and the Coping^Stralegy Indicator. The interaction model was supported for men only. Results indicated that significant interactions between Perceived Job Requirements Underemployment by avoidance copings and Subjective Underemployment by avoidance coping predicted depressive affect for men. Further, the same results were found even after controlling for prior depressive affect. UsingJhe^ selfreport employment status measure revealed significant group differences between unemployed and underemployed men. Underemployed men who utilized more support seeking coping strategies reported higher depressive affect than unemployed men. The interaction model was not supported for women even though women have consistently reported higher depressive affect rates. These results have implications for underemployment and depressive affect research and practical implications for assisting men who feel subjectively underemployed and need to find an appropriate strategy to cope with the situation.

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This research attempted to address the question of the role of explicit algorithms and episodic contexts in the acquisition of computational procedures for regrouping in subtraction. Three groups of students having difficulty learning to subtract with regrouping were taught procedures for doing so through either an explicit algorithm, an episodic content or an examples approach. It was hypothesized that the use of an explicit algorithm represented in a flow chart format would facilitate the acquisition and retention of specific procedural steps relative to the other two conditions. On the other hand, the use of paragraph stories to create episodic content was expected to facilitate the retrieval of algorithms, particularly in a mixed presentation format. The subjects were tested on similar, near, and far transfer questions over a four-day period. Near and far transfer algorithms were also introduced on Day Two. The results suggested that both explicit and episodic context facilitate performance on questions requiring subtraction with regrouping. However, the differential effects of these two approaches on near and far transfer questions were not as easy to identify. Explicit algorithms may facilitate the acquisition of specific procedural steps while at the same time inhibiting the application of such steps to transfer questions. Similarly, the value of episodic context in cuing the retrieval of an algorithm may be limited by the ability of a subject to identify and classify a new question as an exemplar of a particular episodically deflned problem type or category. The implications of these findings in relation to the procedures employed in the teaching of Mathematics to students with learning problems are discussed in detail.