It is no unknown fact that South African learners underachieve in mathematics. Due to the fact that the quality of mathematics teaching is one possible factor that has an influence on learners' mathematics achievement, there are valid reasons questioning the conceptual mathematical knowledge of mathematics teachers. In order to facilitate conceptual understanding teachers themselves must possess profound mathematical knowledge. Apart from the influence of a teacher's knowledge for teaching, teachers' attitudes and beliefs play a meaningful role in the way they teach mathematics. The deficient nature of prospective and practising teachers' knowledge of school mathematics, as well as their attitudes and beliefs towards mathematics has serious implications for the training of prospective mathematics teachers. Literature reveals that a technologically enhanced environment can improve the conceptual learning of prospective mathematics teachers. The purpose of this study was to determine the influence of a dynamic technologically enhanced environment on the attitudes and beliefs, as well as the conceptualisation of prospective mathematics teachers regarding the function concept. In this study, prospective teachers were exposed to Geometer's Sketchpad®, a dynamic software programme providing a powerful learning context that promotes the investigation of algebraic relationships. In order to answer the research question, an explanatory mixed method design was used. In the quantitative part of the study, the Study Orientation Questionnaire in Mathematics and a function test were administered to prospective teachers. In the latter, conceptualisation of the function concept was measured in terms of four competence components, namely interpretation, modelling, translation and reification. In the qualitative part of the investigation semi-structured and task-based interviews were held with a group of prospective teachers. Analysis of the results revealed that the dynamic technologically enhanced environment did not contribute to an improvement of the prospective teachers' attitudes and beliefs. In fact, these decreased visibly. Regarding their conceptualisation, only the reification component showed a practically significant improvement. It therefore appears as if prospective teachers are not being prepared to benefit from the dynamic technologically enhanced environment. A model is proposed for the effective use of such a learning environment. The model involves that diagnostic assessment be made of prospective teachers' basic knowledge of the function concept, their study habits, their attitudes and beliefs with respect to mathematics, as well as their mathematics anxiety. The second component comprises recommendations made to prospective teachers as a result of the diagnostic assessment, as well as continuous support being offered as an integrated part of the mathematics module. Support is offered with respect to cognitive and meta-cognitive skills, affective factors and the creation of an advantageous technologically enhanced learning environment. Despite the restricted value of generalisation of the findings from this study, I still recommend the expansion, refining and implementation of the model so that prospective mathematics teachers can effectively benefit from a technologically enhanced environment. Key words for indexing: mathematics education, mathematics teacher education, teacher knowledge, prospective mathematics teachers, function concept, conceptual learning, tertiary education. / Thesis (Ph.D. (Education))--North-West University, Potchefstroom Campus, 2009.

I assessed the accuracy of two clinical prediction rules, the d-dimer blood test and point of care ultrasound for diagnosing lower limb deep vein thrombosis. Emergency physicians were trained in ultrasound and prospectively scanned emergency department patients with suspected deep vein thrombosis. Accuracy of the Wells and AMUSE rules and the ultrasound result was compared to radiology-performed ultrasound and a 90-day clinical outcome. Univariate and multivariate analyses were performed assessing which factors were associated with the outcome. The sensitivity and specificity of the Wells score for the clinical outcome was 85.7% and 68.5%; the AMUSE score 85.7% and 54.4%. Ultrasound had a sensitivity of 91.7% and specificity of 91.7% for radiology-diagnosed thrombus and 78.6% and 95.0% for clinical outcome. The odds ratio of a positive outcome with a positive ultrasound was 65.1. After receiving the ultrasound training program, emergency physicians were unable to demonstrate sufficient accuracy to replace current diagnostic strategies.

Objectives: Inadequate maternal vitamin D (25(OH)D) levels during pregnancy may affect primary tooth calcification predisposing enamel hypoplasia (EH), a risk factor for Early Childhood Caries (ECC). The purpose of the study was to determine the relationship between 25(OH)D status of expectant mothers and the incidence of EH and ECC among their infants. Methods: This prospective study recruited expectant mothers during their second trimester of pregnancy. A prenatal questionnaire was completed and serum sample drawn for a 25(OH)D assay. Infant dental exams, scheduled at approximately 12 months of age, determined EH and ECC, at which time the mother completed a second questionnaire. The dental examiner was blinded to each mother's prenatal vitamin D status. Results: 207 women, 90% of whom self-declared Aboriginal heritage, were enrolled at a mean age of 19.0 ± 4.7 years. The mean serum 25(OH)D was 48.1 ± 24.4 nmol/L. 35% had levels ≤ 35 nmol/L, a formerly-defined threshold of deficiency. Only 10% of women had concentrations ≥ 80 nmol/L, denoting adequacy. 135 infants were examined at 16.1 ± 7.4 months of age. EH was identified in 22% of infants, 23% had ECC and (36% ECC when white spot lesions were included). Mothers of children with EH had lower mean serum 25(OH)D concentrations during pregnancy than mothers of children without EH (43.2 ± 21.1 vs. 51.4 ± 27.4 nmol/L, p=.072). Mothers of children with ECC had lower 25(OH)D levels than mothers whose children were caries-free (41.4 ± 20.4 vs. 52.4 ± 27.4 nmol/L, p=.045). The rate of untreated decay was inversely related with maternal vitamin D concentrations (p<.001). Infants with EH were significantly more likely to have ECC (p<.001). Logistic regression identified low maternal calcium levels (p=.034), not having heard of vitamin D (p=.036), and not using margarine daily (p=.024) as being significantly associated with EH in the primary dentition of infants. Backwards logistic regression revealed that EH (p<.001), infant age (p=.002), and lower 25(OH)D levels during pregnancy (p=.019) were significantly associated with ECC. Conclusions: This study shows for the first time that maternal vitamin-D levels may influence primary dentition and the development of ECC in their babies.

The purpose of this study was to examine the development of the ability to multitask in children along with other executive control processes that likely underlie goal-directed behavior in novel situations. 35 children, ages 7-11, completed an experimental multitasking paradigm, the Children’s Multiple Activities Game (CMAG), and an existing measure, the Six Parts Test (SPT) as well as two working memory and inhibition tasks and a prospective memory task. Results indicated that multitasking ability improves across this age range and is related to a number of executive abilities. Performance on the CMAG was related to a number of executive abilities, while the SPT was unrelated to these measures. To our knowledge, this is the first study to investigate the development of this ability in children. Findings will be discussed in terms of how this ability develops in relation to cognitive processes that are crucial and account for its variation.

Objectives: The ability to remember to carry out future intentions (prospective memory or ProM) has been shown to be impaired in individuals with severe traumatic brain injury (TBI). However, it is not known whether such deficits extend to people with milder TBI. This study sought to investigate the status of event-based ProM in a sample with a wide range of TBI severity. Furthermore, it proposed to determine whether perceptually salient cues and the formation of implementation intentions, shown to be beneficial in other populations, are also helpful for people with TBI. A detailed error analysis was performed, and the relationship of objective ProM performance to subjective ProM and to scores on other cognitive tests was investigated in an attempt to clarify the mechanisms underlying ProM performance post-TBI. Method: The sample consisted of 20 individuals who sustained a mild (n=10) or severe (n=10) TBI at least 6 months earlier and 20 age-, gender-, and education-matched healthy adults below the age of 55. The groups did not differ in terms of level of pain or substance abuse; however, the TBI group endorsed more symptoms on the Beck Depression Inventory-lI (BDI-II) and on the Beck Anxiety Inventory. They completed two event-based ProM tasks, a game entitled Navigating Your Week (NYW) and the Prospective Remembering of Actions and Sentences (PROAS). Each measure was designed to create intentions that would prompt different actions in response to various cues. They also completed the Prospective and Retrospective Memory Questionnaire (PRMQ) to assess subjective evaluation of memory, the Rey Auditory Verbal Learning Test (RAVLT) and cued recall tasks to assess retrospective memory, and Digit Span Backward to measure working memory. Results: Participants with TBI scored significantly below controls on the NYW game, even after controlling for BDI-II scores, and the two TBI subgroups performed similarly. Participants with TBI made more ProM failures and loss of content errors than controls on the NYW game. The groups performed similarly on the PROAS when it was the second ProM task administered. Although salient cues increased the frequency of responding upon cue presentation, they did not increase response accuracy and thus, did not result in greater fulfillment of intentions. The formation of implementation intentions (lid not enhance the ability to carry out previously formed intentions. The TBI group's performance on the NYW and on the PROAS was associated with their scores on Digit Span Backward and on cued recall measures. The PROAS was also related to delayed recall on the RAVLT; the association between the NYW and the RAVLT did not reach statistical significance. The TBI group endorsed more prospective and retrospective memory problems on the PRMQ as compared to the control group, but their self-ratings were not significantly related to their ProM performance. Conclusions: Individuals with TBI fulfilled fewer of their intentions than controls, particularly on the NYW game, because they failed to respond to cues and had more difficulty remembering the content of their intentions. Their reduced ProM was not fully attributable to depressive symptomatology and was not related to their subjective ProM complaints, despite their greater ProM concerns as compared to controls. Deficits may be attenuated when ProM situations emphasize more automatic retrieval as compared to strategic monitoring processes. Working memory and retrospective memory may both contribute to ProM status after TBI. Cue saliency did not help TBI participants to carry out more intentions; however, it reduced the frequency of ProM failures. The lack of implementation intention effects may be related to study design characteristics. The NYW game appears to he a sensitive, valid, and reliable tool that could he useful in a rehabilitation setting.

Background: Androgens are important in prostate cancer development but how circulating levels of androgens affect risk of prostate cancer of different aggressiveness is not clear. Being childless has been associated with a lower risk of prostate cancer, but it is not clear if this association is causal or a result of residual confounding. Fathering of dizygotic twins, a marker of high fertility, has not been studied in relation to risk of prostate cancer. Another marker of life-long hormonal exposure is height, which has been associated with increased risk of cancer and cancer death. However, the association to separate cancer sites has not been consistent. The aims of this thesis were to study hormonal factors (paper I), and proxies of hormonal factors (paper II and III), and risk of prostate cancer; as well as height and risk of cancer and cancer death by separate sites (paper IV). Methods: Study designs were i) case-control studies, nested within the Västerbotten Intervention Project (paper I), and in Prostate Cancer database Sweden 2.0 (PCBaSe 2.0) (paper II and III), and ii) cohort study, in the Metabolic Syndrome and Cancer project (Me-Can) (paper IV). Results, prostate cancer: In paper I, increasing levels of serum androgens were not associated with risk of prostate cancer overall or in tumor risk categories. In paper II, childless men had a lower risk of prostate cancer, overall and in all risk categories, compared to fathers, an association which was in part explained by differences in marital status and educational level.  In paper III, fathers of dizygotic twins did not have an increased risk of prostate cancer, either overall or in risk categories, when compared to fathers of singletons. Results, cancer overall: In paper IV, height was associated with an increased risk of cancer and cancer death overall in both women and men. The strongest association for cancer was to malignant melanoma in both women and men, and for cancer death to post-menopausal breast cancer in women and renal cell carcinoma in men. Conclusions: These studies indicate that hormonal factors, when studied as serum levels or when studied using proxies of fertility, do not have a major impact on the risk of prostate cancer. The association between height and an increased risk of cancer appears robust for total cancer and cancer death, as well as for several separate cancer sites.

Background and Objectives: Little is known about the impact of nicotine replacement therapy (NRT) use duration on smoking cessation in the general population. This study determines whether duration of NRT use is associated with smoking cessation. Methods: Data were from the Ontario Tobacco Survey longitudinal study of a population-based cohort of baseline smokers who made serious quit attempts during 18 months of follow-up. The association between NRT (any NRT, patches, or gum) use duration and smoking cessation outcomes (short-term abstinence ≥1 month and long-term abstinence ≥12 months) was estimated by Poisson regression, adjusting for all confounding variables. Results: Among the 1,590 eligible smokers, 933 (59%) did not use any NRT, 535 (34%) used NRT <8 weeks, and 112 (8%) used NRT ≥8 weeks at follow-up. The median duration of NRT use was 14 days. A consistent “J” shape of associations between quit aid use duration and smoking cessation outcomes (quit rates) was found. Using any NRT, patches, or gum <8 weeks was generally associated with a lower likelihood of quitting, but using them ≥8 weeks was generally associated with a higher likelihood of quitting, compared to not using them. Only using patches for the recommended duration (≥8 weeks) was associated with a higher likelihood of short-term (relative risk, RR 1.74, 95% confidence interval, CI 1.21-2.50) and long-term (RR 2.62, 95% CI 1.25-5.50) abstinence at the end of 18 months of follow-up, compared to not using patches. Using gum ≥8 weeks was not associated with short- or long-term abstinence at the end of 18 months of follow-up. Conclusions: Using nicotine patches for the recommended duration is associated with successful short- and long-term abstinence in the general population. More efforts are needed to encourage smokers to use nicotine patches for eight or more weeks when attempting to quit.

Background and Objectives: Little is known about the impact of nicotine replacement therapy (NRT) use duration on smoking cessation in the general population. This study determines whether duration of NRT use is associated with smoking cessation. Methods: Data were from the Ontario Tobacco Survey longitudinal study of a population-based cohort of baseline smokers who made serious quit attempts during 18 months of follow-up. The association between NRT (any NRT, patches, or gum) use duration and smoking cessation outcomes (short-term abstinence ≥1 month and long-term abstinence ≥12 months) was estimated by Poisson regression, adjusting for all confounding variables. Results: Among the 1,590 eligible smokers, 933 (59%) did not use any NRT, 535 (34%) used NRT <8 weeks, and 112 (8%) used NRT ≥8 weeks at follow-up. The median duration of NRT use was 14 days. A consistent “J” shape of associations between quit aid use duration and smoking cessation outcomes (quit rates) was found. Using any NRT, patches, or gum <8 weeks was generally associated with a lower likelihood of quitting, but using them ≥8 weeks was generally associated with a higher likelihood of quitting, compared to not using them. Only using patches for the recommended duration (≥8 weeks) was associated with a higher likelihood of short-term (relative risk, RR 1.74, 95% confidence interval, CI 1.21-2.50) and long-term (RR 2.62, 95% CI 1.25-5.50) abstinence at the end of 18 months of follow-up, compared to not using patches. Using gum ≥8 weeks was not associated with short- or long-term abstinence at the end of 18 months of follow-up. Conclusions: Using nicotine patches for the recommended duration is associated with successful short- and long-term abstinence in the general population. More efforts are needed to encourage smokers to use nicotine patches for eight or more weeks when attempting to quit.

Les changements d'orientation de la politique d'aménagement du territoire en France se sont accompagnés de l'essor de la prospective territoriale. En raison cependant des difficultés de transfert des principes de la prospective générale à l'analyse du territoire, la mise en œuvre de ces démarches en reste souvent à l'état d'analyses sectorielles et prennent en compte les territoires comme cadres d'observation et de projection des évolutions sociétales. Une des difficultés de la prospective territoriale est la prise en compte des logiques et des dynamiques de différenciation spatiale localement à l'œuvre dans les territoires avant de les intégrer dans la réflexion prospective. L'objet de la thèse est d'envisager les fondements théoriques et les applications méthodologiques d'une recherche prospective qui replace l'espace et ses principes de différenciation, sa logique de changement et ses contraintes au cœur de l'analyse de l'évolution des territoires. Les terrains à bâtir (achetés par des particuliers et destinés à de l'habitat individuel) constituent un marqueur d'évolution des espaces privilégié dans l'approche dite de " prospective spatiale " défendue dans cette thèse. Les logiques d'acquisition du foncier à bâtir, traduction des processus de production et de transformation de l'espace géographique, informent sur les changements territoriaux à venir. Trois analyses de logiques foncières sont menées sur des territoires de la Région PACA, la Provence intérieure, littorale et préalpine, associant formalisations quantitatives et analyses qualitatives dans une démarche de recherche exploratoire. Elles permettent de définir la potentialité des territoires, leur sensibilité au changement et les degrés de liberté de leur devenir, et indiquent des modalités d'actions d'aménagement adaptées à leurs enjeux actuels et à venir. L'intérêt est de constituer un socle de connaissances utiles à l'élaboration du projet de territoire. Les outils d'analyse spatiale tels que la statistique exploratoire et spatiale, la cartographie, la modélisation graphique... sont mobilisés pour qualifier chacune de ces trois notions. La recherche aboutit à une proposition de protocole de démarche de prospective spatiale

The aim of this thesis is to identify and assess the reasons of the Turkish financial crises based on various crises model explanations including the first, the second and the third generation models. It is argued that following factors played a crucial role in triggering crises in Turkey. Firstly, under the weak sustainable fiscal policies, implementation of the exchange rate based stabilization program caused the increase in vulnerabilities in the sectoral balance sheets and thus increased the prospective deficit considerations. Secondly, as seen on the international evidence, over-appreciation of the domestic currency put pressure on the current account deficit and other macroeconomic indicators. Thirdly, domestic and external factors also worsen the perceptions on the sustainability of the disinflation program leading to sharp capital outflows. Within this context, fiscal and current account sustainability are empirically tested under the light of the structural break analysis and it is found that fiscal stance and the current account deficit are both weakly sustainable implying the necessity of policy regime changes before the crises period. Having assessed the structural problems of the government, corporate and banking sector&rsquo / s balance sheets, intersectoral risk matrix was constructed to analyze the risk accumulation in the sectors considering the impacts of the exchange rate based disinflation program and the ongoing economic imbalances. Both mismanagement of the risks and the structural weaknesses of some banks led to the deterioration of the expectations about the continuity of the program, by increasing tensions and prospective deficit perceptions in the markets. With speculative attacks, a sharp capital outflow was triggered the crises. It is concluded that the causes of the 2000-2001 Turkish financial crises can be interpreted as an example of financial crises model encompassing all elements of the earlier models except seignorage issues.