Magister Educationis - MEd / The study focuses on the administration procedure of Adjusted Rorschach Comprehensive System (ARCS) to learners from a previously disadvantaged school in the Western Cape. ARCS is the Rorschach administration procedure developed by Moletsane-Kekae (2004) in her research study. The aim of the study was to determine the response rate of learners from a previously disadvantaged school when they were exposed to the Adjusted Rorschach Comprehensive System (ARCS). The objectives are to determine the possible factors that can lead to high and low response rate when administering Adjusted Rorschach Comprehensive System (ARCS). The main assumption that guides the study was that the responses of the administration of Adjusted Rorschach Comprehensive System (ARCS) to the learners from a previously disadvantaged school in the Western Cape would yield more than 14 responses (R>14). The study adopted a qualitative approach, case study design, interpretivist paradigm. The Rorschach test, ARCS procedure, observation, interview, and Field notes were used as data collection techniques. The sample was made of six learners (3 girls and 3 boys) in Year 1 selected from a previously disadvantaged school in Cape Town. In order to analyze the data, the thematic analysis and interpretation procedures were used. The results revealed that the majority of the learners gave high responses, because the ARCS accommodated their cultures, believe and backgrounds. This study found out that language, seating arrangement, strategies using during the ARCS procedure were the factors that influenced the higher response rate. Furthermore, the study also found that the lack of previous exposure and experience of the psychological test was a factor that can lead to low response.

Analysing fertility developments in selected European countries between 1970 and 2014 using alternative methods Abstract Transversal fertility indices as the total fertility rate are distorted by tempo effect when timing of childbearing is changing. New indices as the tempo-adjusted total fertility rate remove this distortion and give another perspective on fertility trends in countries with present tempo effect. These countries are former Eastern Bloc countries and other European countries. This thesis uses the tempo-adjusted total fertility rate and data from Human Fertility Database to describe tempo distortion in fertility level in Sweden, Norway, Czechia, Slovakia, Estonia and Lithuania in period 1970-2014. A more detailed analysis by parity in Sweden and Czechia is conducted in the same period. Negative tempo effect has been present from 1970s in Sweden and Norway and then from 90s in the countries left with fertility postponement being very widespread. The tempo effect level in Sweden and Czechia was substantial at parity one and diminishing with higher parities. Keywords: fertility, timing, level, postponement, adjusted total fertility rate, tempo effect Number of characters without blank spaces: 138 653

Bakgrund: Både aktieinvesteringar samt fastighetsinvesteringar har blivit populära investeringsalternativ hos den svenska befolkningen. Låga bostadsräntor och nya förmånliga aktiesparformer har bidragit till ett gynnsamt investeringsklimat på både fastighetsmarknaden och aktiemarknaden. Trots osäkerheter relaterade till utbrottet av coronapandemin nådde båda marknader rekordhöga prisnivåer under 2020 och förväntningarna på marknaderna har varit fortsatt höga. Eftersom det saknas tidigare studier på den svenska marknaden kring vilken investering som faktiskt har varit den mest lönsamma samt hur korrelationen ser ut mellan tillgångarna är detta av intresse att studera. Syfte: Syftet med denna studie är att jämföra den riskjusterade avkastningen mellan en aktieinvestering och en bostadsrättsinvestering under olika tidsperioder samt studera korrelationen mellan dessa två tillgångar på lång sikt och under coronapandemin.  Metod: Studien har genomförts med en kvantitativ metod samt en deduktiv ansats. Månadsdata för aktieindexet OMXSPI samt prisdata för bostadsrätter på den svenska marknaden har inhämtats för tidsperioden 2011–2020. Den riskjusterade avkastningen och korrelationen har beräknats för att undersöka eventuella skillnader mellan de två tillgångsslagen. Slutligen har signifikanstester gjorts på resultatet och regressioner har genomförts för att analysera sambandet mellan volatilitet och avkastning. Slutsats: Resultatet visade inte på någon signifikant skillnad mellan de två tillgångsslagens avkastning. OMXSPI visade dock på en högre riskjusterad avkastning än bostadsrätter för alla de studerade tidsperioderna. På lång sikt var korrelationen mellan de två tillgångarna starkt positiv och det gick även att se en förstärkt korrelation under coronapandemin. / Background: Stock- and real estate investments are both investments that have become very popular in Sweden. Low mortgage interest rates and new affordable ways to invest in stock have created an investment friendly climate for both the real estate market and the stock market. Despite uncertainties related to the outbreak of the covid-pandemic, both the realestate market and the stock market reached record high levels in 2020 and the expectations on the market have been continuously high. There is a research gap on the Swedish market regarding which investment is the most profitable and how the two investments correlate witheach other, making it a relevant subject to study. Purpose: The purpose with this essay is to compare the risk-adjusted return between an investment in stock and an investment in real estate and study the long-term correlation between these two investments, and the correlation during the covid-pandemic. Methodology: The study was conducted through a quantitative method and a deductive approach. Monthly data for the stock index OMXSPI and real estate price data from the Swedish market were gathered for the time period 2011-2020. The risk-adjusted return and the correlation was calculated to study potential differences between the two investments. Finally, the results were statistically tested, and regressions were conducted to analyze the relationship between volatility and return. Conclusion: The result did not show any significant difference between the return of the two asset classes. However, OMXSPI did show a higher risk-adjusted return than the real estate index for all studied time periods. The correlation between the two asset classes was strongly positive in the long term and it was also possible to see an increased correlation during the covid-pandemic.

The Diploma thesis deals with financial performance of selected commercial insurances on the Czech and German market in years 2010 - 2014. The thesis includes an external analysis of selected insurance companies based on financial ratios used in insurance and comparing their results each year of the reporting period separately for each insurance company. For increasing the information value of the results is made a comparing insurance companies between themselves. On the basis of results are given recommendations for optimizing unwanted values to improve the financial health of insurances, which is the basis for making profit.

The study evaluated the development role of targeted development investments in South Africa and their risk adjusted performance over a 10-Year period, that is from 2008 to 2017. Targeted development investments as a subset of socially responsible investments have transformed the way capital is allocated towards development funding needs. In the South African context this study is relevant given it offers a contrast between investments made in the public sector where development impact is a key objective, versus private sector targeted investments that aim to achieve financial returns whilst also driving development impact objectives aligned to sustainable development goals. The role and impact of these investments in the post democratic era is put in the spotlight given the country is dealing with economic, social, and environmental challenges that have necessitated the need to assess the nature and role of the investment industry in solving these complex development challenges (Giampocaro & Pretorius, 2012). The study on the role of the public sector focused on the investments and development impact indicators tracked by the Top 3 public sector investment institutions or corporations. The analysis on the performance of the private sector TDI funds examined their risk adjusted performance using Treynor, Sharpe, Sortino, and Information ratios. The risk adjusted performance was used to test whether the TDI fund returns under or outperformed against five benchmark categories. The research findings showed mixed results where TDI funds either underperformed or outperformed against the benchmark categories. The findings highlighted the need for a hybrid development model where both the public and private sector actively play a role in the development landscape as guided by their respective investment mandates. The findings advocate for corporate and institutional investors to increase capital allocations and investments towards financing development needs given the scope to maximise investor returns, whilst considering socially responsible investing and issues relating to the development and empowerment of previously disadvantaged communities.

The thesis examines the strategy of country momentum and is evaluated with 30 different country exchange-traded funds (ETFs) for the period 1996-2018. The empirical evaluation is designed to apply different formation- and holding periods with overlapping portfolios. The results show positive momentum returns in various periods and a few portfolios present a higher average return than the market. However, none of the portfolios is presenting any significant positive returns or alphas, meaning that the three hypotheses cannot be rejected. On the other hand, some portfolios have higher Sharpe ratios and Morningstar value than the market. Thus, meaning that the individual investor could prefer the momentum portfolio over the market despite the insignificant returns.

Avsikten med studien är att undersöka den magiska formelns prestation på den svenska aktiemarknaden mellan åren 2017–2021. Syftet är att undersöka om denmagiska formeln kan uppnå en högre riskjusterad avkastning än OMXS30 underundersökningsperioden. I denna studie tillämpas backtesting med hjälp av historiska data hämtat från Refinitv Eikons databas för att utforska strategins prestation under undersökningsperioden. Målet med denna studie var att undersöka om den magiska formeln kan användas av investerare med mindre erfarenhet för att uppnå en högre riskjusterad avkastning än OMXS30-index. Med hjälp av två variabler, return on capital och earnings yield fick vi fram ett resultat för att besvara studiens syfte. Under hela undersökningsperioden uppnådde den magiska formeln en genomsnittlig avkastning på 15,32% medan OMXS30 portföljen uppnådde en avkastning på 10,78%. Resultatet från denna studie visade att den magiska formeln kunde uppnå en högre avkastning än OMXS30 under undersökningsperioden men eftersom Sharpekvoten för OMXS30 var högre än den magiska formeln formas indikationer att OMXS30 presterade bättre än den magiska formeln på en genomsnittlig riskjusterad nivå under undersökningsperioden. / This study examines the performance of the magic formula by Joel Greenblatt on the Swedish stock market. A back test was performed to see if the magic formula could generate a higher risk adjusted return and outperform the OMXS30 index between the years 2017 and 2021. The study constructed portfolios for each year for the magic formula and OMXS30 with the ambition to compare the two results. The results show that the magic formula achieved a higher return at a higher risk rate so therefore, it was not able to beat the OMXS30 index on a risk adjusted level.

The objective of the thesis was to evaluate the possibility to calculate the unloading distribution between a ventilator and a patient using a new mathematical modelling of the breathing patterns. The modelling used today is considered to lack sufficient precision for clinical use, and is a somewhat simplified model. To evaluate the possibility of a new model, a volunteer test was carried out - recording data such as Edi, pressure, volume and flow. Using this data, and by using a more complex model, tidal volume was estimated and compared to the measured data. The results did not imply any improvement compared to the simpler model regarding the accuracy and the variability. However, more work should be done in this area, as time deficiency prevented further analysis.

Ziel: Diese Studie vergleicht die erosionsprotektiven Eigenschaften verschiedener Fluorid- und/oder Zinnlösungen bei unterschiedlichen pH-Werten. Es wird untersucht, ob fluorid- und/oder zinnhaltige Lösungen im sauren Milieu besser vor Erosionen schützen. Methoden: Hierfür wurden die Monosubstanzen Aminfluorid, Natriummono-fluorphosphat, Natriumfluorid, Zinnfluorid und Zinnchlorid bei einer Fluoridkonzentration von 500 ppm in vitro adjustiert auf die pH-Werte 4,5; 5,5 und 6,5 und in situ adjustiert auf den pH-Wert 4,5 untersucht. In einem In-vitro-Vorversuch wurden die Testlösungen zunächst bei den pH-Werten 4,5-6,5 gescreent. Der In-situ-Hauptversuch wurde mit dem wirksamsten pH-Wert 4,5 durchgeführt. Zur In-situ-Pellikelbildung wurden individuelle Schienen mit je 6 Prüfkörpern von 6 Proband*innen für 30 min oral inkubiert. Nach 1 min wurde für 60 s mit einer Lösung des pH-Wertes 4,5 gespült. Native und mit In-vitro- bzw. In-situ-Pellikel bedeckte Plättchen dienen als Kontrolle. Die Prüfkörper wurden für 120 s in HCl (pH 2,0; 2,3 und 3,0) inkubiert. Die Kalzium- und Phosphatfreisetzungen wurden photometrisch bestimmt (Arsenazo-III- und Malachitgrün-Methode). Ergebnisse: Alle Spüllösungen reduzieren die Mineralfreisetzung aus den Schmelzprüfkörpern verglichen mit der nativen Kontrolle. Im Vergleich zur In-vitro- und In-situ-Pellikel wird die Mineralfreisetzung durch die Monosubstanzen jedoch nicht vermindert. Die Kalzium- und Phosphatfreisetzungen aus den In-situ-Prüfkörpern sind geringfügig niedriger als aus den Proben der In-vitro-Versuchsreihe. Die Monosubstanzen des pH-Wertes 4,5 konnten die Kalzium- und Phosphatfreisetzung in vitro stärker reduzieren als die Lösungen der pH-Werte 5,5 oder 6,5. Der Erosionsschutz von Fluorid- und/oder Zinnlösungen wird im sauren Milieu verbessert. Zinnfluorid reduziert die Mineralfreisetzung in vitro und in situ am stärksten. Die erosionsprotektiven Eigenschaften von Zinnchlorid sind gleichwertig mit denen der konventionellen Lösungen Aminfluorid, Natriummonofluorphosphat und Natriumfluorid. Schlussfolgerungen: Fluorid- und Zinnionen interagieren im sauren Milieu stärker mit der Zahnoberfläche als bei neutraleren pH-Werten – der resultierende protektive Effekt ist somit ausgeprägter. Ein wichtiger Co-Faktor dabei sind die Zinnionen. Die In-situ-Pellikel bietet einen besseren Schutz vor Erosionen als die In-vitro-Pellikel. Daher sind In-situ-Versuche den In-vitro-Versuchen vorzuziehen. / Objective: The distinctive aspect of this study was to ascertain the erosion protective properties of various fluoride and/or stannous solutions at different pH values. The aim was to investigate whether fluoride- and/or tin-containing solutions provide better protection against erosion than solutions with higher pH values. Methods: In an in vitro experiment, amine fluoride, sodium monofluorophosphate, sodium fluoride, stannous fluoride, and stannous chloride at fluoride concentrations of 500 ppm were initially screened and pH values of 4.5; 5.5 and 6.5. The in situ main experiment was conducted at the most effective pH value of 4.5. Individual trays with 6 test specimens for six participants were orally incubated for 30 minutes. After 1 minute, a 60-second rinse was performed with a test solution at pH 4.5. Native and in vitro- or in situ-covered specimens were used as controls. The test specimens were then incubated in HCl (pH 2.0, 2.3, and 3.0) for 120 seconds, and calcium and phosphate release was determined photometrically using the Arsenazo III and Malachite Green methods. Results: All rinsing solutions reduced mineral loss from the enamel test specimens compared to the native control. However, the monosubstances did not significantly reduce mineral loss compared to the in vitro or in situ pellicles. The calcium and phosphate releases from the in situ specimens were slightly lower than those from the in vitro series. The fluoride substances at pH 4.5 exhibited a stronger reduction in calcium and phosphate release in vitro compared to solutions at pH values of 5.5 or 6.5. The erosion protective properties of fluoride and/or stannous solutions were enhanced in an acidic environment. Among all substances, stannous fluoride exhibited the greatest reduction in mineral release both in vitro and in situ. The erosion protection of stannous chloride was comparable to the protection offered by amine fluoride, sodium monofluorophosphate, and sodium fluoride solutions. Conclusions: Fluoride and tin ions interact more strongly with the tooth surface in an acidic environment compared to more neutral pH values, resulting in a more pronounced protective effect. Stannous ions play an important role in this process. In situ pellicles offer better protection against erosions than in vitro pellicles. Therefore, in situ experiments are preferable to in vitro experiments.

I have developed time-varying coefficient models for recurrent event data to evaluate the temporal profiles for recurrence rate and covariate effects. There are three major parts in this dissertation. The first two parts propose a mixed Poisson process model with gamma frailties for single type recurrent events. The third part proposes a Bayesian joint model based on multivariate log-normal frailties for multi-type recurrent events. In the first part, I propose an approach based on penalized B-splines to obtain smooth estimation for both time-varying coefficients and the log baseline intensity. An EM algorithm is developed for parameter estimation. One issue with this approach is that the estimating procedure is conditional on smoothing parameters, which have to be selected by cross-validation or optimizing certain performance criterion. The procedure can be computationally demanding with a large number of time-varying coefficients. To achieve objective estimation of smoothing parameters, I propose a mixed-model representation approach for penalized splines. Spline coefficients are treated as random effects and smoothing parameters are to be estimated as variance components. An EM algorithm embedded with penalized quasi-likelihood approximation is developed to estimate the model parameters. The third part proposes a Bayesian joint model with time-varying coefficients for multi-type recurrent events. Bayesian penalized splines are used to estimate time-varying coefficients and the log baseline intensity. One challenge in Bayesian penalized splines is that the smoothness of a spline fit is considerably sensitive to the subjective choice of hyperparameters. I establish a procedure to objectively determine the hyperparameters through a robust prior specification. A Markov chain Monte Carlo procedure based on Metropolis-adjusted Langevin algorithms is developed to sample from the high-dimensional distribution of spline coefficients. The procedure includes a joint sampling scheme to achieve better convergence and mixing properties. Simulation studies in the second and third part have confirmed satisfactory model performance in estimating time-varying coefficients under different curvature and event rate conditions. The models in the second and third part were applied to data from a commercial truck driver naturalistic driving study. The application results reveal that drivers with 7-hours-or-less sleep prior to a shift have a significantly higher intensity after 8 hours of on-duty driving and that their intensity remains higher after taking a break. In addition, the results also show drivers' self-selection on sleep time, total driving hours in a shift, and breaks. These applications provide crucial insight into the impact of sleep time on driving performance for commercial truck drivers and highlights the on-road safety implications of insufficient sleep and breaks while driving. This dissertation provides flexible and robust tools to evaluate the temporal profile of intensity for recurrent events. / PHD / The overall objective of this dissertation is to develop models to evaluate the time-varying profiles for event occurrences and the time-varying effects of risk factors upon event occurrences. There are three major parts in this dissertation. The first two parts are designed for single event type. They are based on approaches such that the whole model is conditional on a certain kind of tuning parameter. The value of this tuning parameter has to be pre-specified by users and is influential to the model results. Instead of pre-specifying the value, I develop an approach to achieve an objective estimate for the optimal value of tuning parameter and obtain model results simultaneously. The third part proposes a model for multi-type events. One challenge is that the model results are considerably sensitive to the subjective choice of hyperparameters. I establish a procedure to objectively determine the hyperparameters. Simulation studies have confirmed satisfactory model performance in estimating the temporal profiles for both event occurrences and effects of risk factors. The models were applied to data from a commercial truck driver naturalistic driving study. The results reveal that drivers with 7-hours-or-less sleep prior to a shift have a significantly higher intensity after 8 hours of on-duty driving and that their driving risk remains higher after taking a break. In addition, the results also show drivers’ self-selection on sleep time, total driving hours in a shift, and breaks. These applications provide crucial insight into the impact of sleep time on driving performance for commercial truck drivers and highlights the on-road safety implications of insufficient sleep and breaks while driving. This dissertation provides flexible and robust tools to evaluate the temporal profile of both event occurrences and effects of risk factors.