One hundred and eleven mother-child dyads visited the laboratory when children were 10 to 12 years old and again two years later. Children’s self-disclosure to mothers and mothers’ accurate knowledge of effective comforting strategies were examined together in the context of maternal warmth and children’s positive coping. Maternal warmth longitudinally predicted children’s disclosure, and children’s disclosure longitudinally predicted mothers’ accurate knowledge of comforting strategies. Maternal warmth moderated the association between mothers’ accurate knowledge of comforting strategies and children’s positive coping. Specifically, maternal knowledge predicted child coping only in children of cold mothers. Implications for the socialization of coping and the role of child disclosure and parents’ accurate knowledge in parenting interventions are discussed.

The current study evaluated the effects of self-monitoring by swimmers to improve their performance at practice and assessed the effects of reactivity to observer presence on their performance. Additionally, it investigated the accuracy of the swimmers' self-reports. Seven public high school swim team members used program boards to self-monitor in order to increase the number of assigned laps completed at practice. Reactivity to observer presence was assessed by having a confederate record the number of laps completed during observer absent conditions. A series of AB replications and an ABAB reversal design were used. The percentage of assigned laps completed increased during the self-monitoring phases. The self-monitoring and feedback phase showed an additional increase in the percentage of assigned laps completed, and also showed an increase in the mean level of reporting accuracy by the participants. The effects from the reactivity assessment were mixed; the percentage of assigned laps completed was lower on days that the observer was absent compared to the days the observer is present for only some of the participants. More research is needed to examine reactivity effects in sport settings.

Bakgrund: Affärspressen publicerar dagligen rekommendationer och riktkurser från aktieanalytiker och dess analyser kan anses ligga till grund för investeringsbeslut hos såväl privata som institutionella investerare. Aktieanalytikers förmåga att prognostisera aktiekurser är ett outforskat område med endast ett fåtal publicerade studier på variabeln riktkurs. Tidigare studier fokuserar på att utvärdera träffsäkerheten i prognoserna men få av dessa bidrar till förståelse kring vad som påverkar prognosfelens storlek. Syfte: Syftet med studien är att analysera aktieanalytikers förmåga att prognostisera framtida aktiekurser. Genomförande: Studiens deduktiva ansats gör att resultat från tidigare studier ligger till grund för formulering av forskningsfrågor och utformning av tänkbara påverkansfaktorer för träffsäkerhet. Träffsäkerheten i riktkurserna analyseras via regressionsanalys där det absoluta prognosfelet är beroende variabel medan de formulerade påverkansfaktorerna är förklarande variabler. Vidare studeras en eventuell närvaro av överoptimism i prognoserna genom att undersöka fördelningen av det relativa prognosfelet via T-test. Resultat: Aktieanalytikers riktkurser påverkas av flertalet faktorer, där ett bolags storlek och beta uppvisar tydligast samband med träffsäkerheten. Variablerna uppvisar ett positivt samband med träffsäkerheten i prognoserna. Indikationer återfinns på att aktieanalytiker inte agerar fullständigt rationellt och att psykologiska påverkansfaktorer kan förekomma. Köprekommendationer influeras av en överoptimism medan säljrekommendationer uppvisar en överdriven pessimism. / Background: On a daily basis, the business press publishes stock recommendations and earnings estimates that stock analysts’ produce. These recommendations can be viewed as an integral part of both private and institutional investors’ investment decisions. Stock analysts’ ability to predict stock prices is an unexplored area with only a few studies on the variable target price. Previous studies focus on evaluating the accuracy of the forecasts but few of them contribute to the understanding of which factors influence the size of the forecast errors. Aim: The aim of the thesis is to analyze stock analysts’ ability to predict future stock prices. Completion: A deductive approach is used which allows the formulation of research questions and the identification of possible influencing factors on accuracy to be derived from previous studies. The accuracy is analyzed using regression analysis, where the absolute forecast error is the dependent variable while the formulated influencing factors are used as explanatory variables. Furthermore an analysis of the relative forecast errors is conducted to examine whether overoptimism influences the forecasts. This is carried out by examining the distribution of the relative forecast errors using T-tests. Results: Stock analysts’ price targets are influenced by several of the examined factors. A company’s size and its beta value exhibit the strongest influence on target price accuracy. The variables display a positive relationship with the accuracy of the forecasts. The results indicate that stock analysts’ do not act completely rational and that psychological biases may affect the target prices. Buy recommendations are influenced by an overoptimism whereas sell recommendations show an exaggerated pessimism.

Improving and predicting the accuracy of positioning estimates derived from the global positioning system (GPS) continues to be a problem of great interest. Dependable and accurate positioning is especially important for navigation applications such as the landing of commercial aircraft. This subject gives rise to many interesting and challenging mathematical problems. This dissertation investigates two such problems. The first problem involves the study of the relationship between positioning accuracy and satellite geometry configurations relative to a user's position. In this work, accuracy is measured by so-called dilution of precision (DOP) terms. The DOP terms arise from the linear regression model used to estimate user position from GPS observables, and are directly related to user position errors. An analysis of the statistical properties explaining the behavior of the DOP terms is presented. The most accurate satellite geometries and worst configurations are given for some cases. The second problem involves finding methods for detecting and repairing cycle-slips in range delay data between a satellite and a receiver. The distance between a satellite and a receiver can be estimated by measuring the difference in the carrier frequency phase shift experienced between the satellite and receiver oscillators. Cycle-slips are discontinuities in the integer number of complete cycles in these data, and are caused by interruptions or degradations in the signal such as low signal to noise ratio, software failures, or physical obstruction of the signals. These slips propagate to errors in user positioning. Cycle-slip detection and repair are crucial to maintaining accurate positioning. Linear regression models and sequential hypothesis testing are used to model, detect, and repair cycle-slips. The effectiveness of these methods is studied using data obtained from ground-station receivers.

Environmental Impact Assessment (EIA) is recognised worldwide as a tool for identifying the potential adverse effects of a proposed development on the environment. Very little attention has been given to determining the actual environmental effects resulting from a development. The need for EIA follow–up (i.e. monitoring, auditing, evaluation, management and communication) was identified and would form the building blocks within the EIA process. Follow–up provides information about the consequences of an activity and presents opportunities to implement adequate mitigation measures. EIA follow–up is not developed to its full potential even though the need for it is acknowledged and supported in legislation, scientific journals and scientific books. EIA follow–up necessitates feedback in the EIA process to ensure lessons learnt and outcomes from past experiences can be applied in future actions. Follow–up is only a legal requirement if conditions are specified in the environmental authorisation (EA). Of particular concern to follow–up is the accuracy of prediction and secondly, the level of compliance to conditions set out in the authorization and management plans. This study will focus primarily on critically analysing predictions and compliance from the construction phase of a high profile mega shopping mall project, namely the Mooi River Mall (MRM), with an analysis to gauge the actual effect and contribution of the EIA process to decision making and implementation practices. Multiple data sources were used to determine the accuracy of predictions and legal compliance level of the Mooi River Mall. The Mooi River Mall's accuracy of predictions (66%) and legal compliance (83%) suggest that some of the impacts were unavoidable; that mitigation measures were either not implemented or identified or that EIA follow–up served its purpose in the form of implementing effective auditing programmes to monitor legal compliance. / Thesis (M.Sc (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

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.

Environmental Impact Assessment (EIA) is recognised worldwide as a tool for identifying the potential adverse effects of a proposed development on the environment. Very little attention has been given to determining the actual environmental effects resulting from a development. The need for EIA follow–up (i.e. monitoring, auditing, evaluation, management and communication) was identified and would form the building blocks within the EIA process. Follow–up provides information about the consequences of an activity and presents opportunities to implement adequate mitigation measures. EIA follow–up is not developed to its full potential even though the need for it is acknowledged and supported in legislation, scientific journals and scientific books. EIA follow–up necessitates feedback in the EIA process to ensure lessons learnt and outcomes from past experiences can be applied in future actions. Follow–up is only a legal requirement if conditions are specified in the environmental authorisation (EA). Of particular concern to follow–up is the accuracy of prediction and secondly, the level of compliance to conditions set out in the authorization and management plans. This study will focus primarily on critically analysing predictions and compliance from the construction phase of a high profile mega shopping mall project, namely the Mooi River Mall (MRM), with an analysis to gauge the actual effect and contribution of the EIA process to decision making and implementation practices. Multiple data sources were used to determine the accuracy of predictions and legal compliance level of the Mooi River Mall. The Mooi River Mall's accuracy of predictions (66%) and legal compliance (83%) suggest that some of the impacts were unavoidable; that mitigation measures were either not implemented or identified or that EIA follow–up served its purpose in the form of implementing effective auditing programmes to monitor legal compliance. / Thesis (M.Sc (Environmental Science))--North-West University, Potchefstroom Campus, 2011.

This thesis addresses different questions regarding the rate, efficiency, and accuracy of peptide bond formation with natural as well as unnatural amino acids: Which step is rate-limiting during peptide bond formation? How does the accuracy vary with different transfer RNAs (tRNAs) and codons and how is it relevant to the living cells? Does proofreading selection of codon reading occur in a single- or multi-step manner as theoretically suggested? How does the E. coli translation system discriminate unnatural amino acids? Based on that, how to improve the incorporation efficiencies of unnatural amino acids? Based on the study on pH dependence of peptide bond formation, we show that the rate of the chemistry of peptidyl transfer to aminoacyl-tRNA (AA-tRNA) Gly-tRNAGly or Pro-tRNAPro limits the rate of peptide bond formation at physiological pH 7.5, and this could possibly be true for peptidyl transfer to all natural AA-tRNAs at physiological condition. By studying the efficiency-accuracy trade-off for codon reading by seven AA-tRNA containing ternary complexes, we observe a large variation on the accuracy of initial codon selection and identify several error hot-spots. The maximal accuracy varied 400-fold from 200 to 84000 depending on the tRNA identity, the type and position of the mismatches. We also propose a proofreading mechanism that contains two irreversible steps in sequence. This could be highly relevant to the living cells in relation to maintaining both high accuracy and high efficiency in protein synthesis. Finally, we show that peptide bond formation with small and large non-N-alkylated L- unnatural amino acids proceed at rates similar to those with natural amino acids Phe and Ala on the ribosome. Interestingly, the large side chain of the bulky unnatural amino acid only weakens its binding for elongation factor Tu (EF-Tu) but not slows down peptidyl transfer on the ribosome. Our results also suggest that the efficiency of unnatural amino acid incorporation could be improved in general by increasing EF-Tu concentration, lowering the reaction temperature and / or using tRNA bodies with optimal affinities for EF-Tu in the translation system.

Reservoir Simulation is a very powerful tool used in the Oil and Gas industry to perform and provide various functions including but not limited to predicting reservoir performance, conduct sensitivity analysis to quantify uncertainty, production optimization and overall reservoir management. Compared to explored reservoirs in the past, current day reservoirs are more complex in extent and structure. As a result, reservoir simulators and algorithms used to represent dynamic systems of flow in porous media have invariably got just as complex. In order to provide the best solutions for analyzing reservoir performance, there is a need to continuously develop reservoir simulators and reservoir simulation algorithms that best represent the performance of the reservoir without compromising efficiency and accuracy. There exists several commercial reservoir simulation packages in the market that have been proven to be extremely resourceful with functionality that covers a wide range of interests in reservoir simulation yet there is the constant need to provide better and more efficient methods and algorithms to study and manage our reservoirs. This thesis aims at bridging the gap in the framework for developing these algorithms. To this end, this project has both an educational and research component. Educational because it leads to a strong understanding of the topic of reservoir simulation for students which can be daunting especially for those who require a more direct experience to fully comprehend the subject matter. It is research focused because it will serve as the foundation for developing a framework for integrating custom built external simulators and algorithms with the workflow of the model builder of our reservoir simulation package of choice i.e. Petrel with the Ocean programming environment in a seamless manner for simulating large scale multi-physics problems of flow in highly heterogeneous flow of porous media. Of particular interest are the areas of model order reduction and production optimization. In-house algorithms are being developed for these areas of interest and with the completion of this project. We hope to have developed a framework whereby we can take our algorithms specifically developed for areas of interest and add them to the workflow of the Petrel Model Builder. Currently, we have taken one of our in-house simulators i.e. a two dimensional, oil-water five-spot water flood pattern as a starting point and have been able to integrate it successfully into the “Define Simulation Case” process of Petrel as an additional choice for simulation by an end user. In the future, we will expand this simulator with updates to improve its performance, efficiency and extend its capabilities to incorporate areas of research interest.

There have been increased efforts to develop methods for improving attention across a range of tasks including those assessing sustained attention. Using a variety of techniques, researchers have reported modest reductions in errors on sustained attention tasks. However, published reports often have not documented changes in response times (RTs) that might accompany error reductions, which is problematic given that the error reductions could be mediated by a slowing strategy (i.e., speed-accuracy trade-off). In three studies, I explored the effects of speed-accuracy trade-offs in a sustained attention task (The Sustained Attention to Response Task; SART). In Study 1, I examined the effects of changing SART instructions from the double-edged "be fast and accurate" to the more conceptually accurate goal of maintaining high accuracy by responding slowly and carefully, and found that instructions to respond slowly and accurately resulted in both significantly longer RTs and fewer SART errors. In Studies 2 and 3, I developed a modified version of the SART that allowed me to experimentally manipulate RTs and found that errors were a systematic function of manipulated differences in RT independent of individual differences in response strategies. The results of these experiments indicate that it is possible that any technique that alters RT might indirectly alter error rates independently of improvements in sustained attention. I therefore conclude that investigators need to carefully attend to, control for, and report any changes in RT that accompany improvements in accuracy of performance, or alternatively employ tasks controlling for RT.