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Significant Alphas in Real Estate FundsRogers, Nina 08 1900 (has links)
This study provide empirical evidence whether bias in the standard errors of Jensen’s alpha explains conflicting results in the extant literature in real estate funds. Significant alphas in real estate mutual funds and REITs are compared with heteroskedasticity consistent covariance matrix estimators (HC1, HC2 and HC3), Newey-West standard errors, a robust regression tempering the effect of high leverage points, a GARCH model, and a HC3 adjusted wild bootstrap. In the analysis of real estate mutual funds and a separate sample set of REITs, the HCCME had a minimal impact attenuating the number of firms with excess returns. Contrary to expectations the differences from HC1 to HC2 to HC3 were also negligible. The Newey-West standard error provided highly variable results when compared with the OLS results particularly in the REIT sample. Of the techniques to adjust for bias in the standard error, the wild bootstrap with HC3 adjustment to the standard error provided the most conservative result to the number of real estate mutual funds and REITs with significant alphas. The co-movement of real estate funds suggests common exogenous influences. Including state variables such as the changes in unexpected inflation, term spread, default spread, market skewness and industrial production growth in a multi-factor model is used to identify systemic economic factors in significant alphas. The significant alphas varied with the inclusion of these variables, the time period and the bias adjustment.
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An investigation into the relationship between satisfaction with life and sense of coherence amongst the unemployedMankayi, Dolphia Thozama January 1996 (has links)
Magister Commercii (Industrial Psychology) - MCom(IPS) / The present study investigated the relationship between the Sense Of Coherence and Satisfaction With Life amongst the unemployed.
The study attempted to test the following hypotheses. 1. People with a high Sense Of Coherence tend to be satisfied with their lives in general. 2. Demographic variables such as age, gender, race and level of education have an influence on the subjects' scores on the Sense Of Coherence and Satisfaction With Life scales. 3. Length of unemployment has an impact on the subjects' Sense Of Coherence and Satisfaction With Life. In this study, subjects were drawn from the Department of Manpower in the Western Cape region. The data were obtained from a sample of 100 participants. Of this 100, 52 were males. Subjects were asked to complete the Sense Of Coherence and the Satisfaction With Life scales. Statistical procedures that were used are Multiple Linear Regression analysis, Product Moment Correlational Co-efficients, Analysis of Variance test (ANOVA) and the Cronbach Alphas of the various scales. It was found that Sense Of Coherence correlated significantly with Satisfaction With Life, thus supporting the first hypothesis. This led to the conclusion that a person with a strong Sense Of Coherence tends to be more satisfied with his/her life. However, a person with a weaker Sense Of Coherence finds it difficult to make sense out of his/her life. It was also found that most of the demographic variables did not reach any statistical significance. The general trend in this sample was that younger people had higher education and had been unemployed for fewer years. In comparison, older people were found to have less education and had been unemployed for more years. It was concluded that formal and informal education system will be necessary to develop and equip both young and older people with the experience and skills to use at work. This study was concluded by the discussion of the implications of the findings and suggestions for future research.
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Application de la scintillation liquide pour caractériser une source de curiethérapie par émetteurs-alphas diffusantWahl, Mathilde 08 1900 (has links)
Cancer is the leading cause of death in Canada. Many cancer treatments are using chemotherapy, surgery and radiotherapy. In radiotherapy, photons are the most used ionizing radiation, however alpha particles have higher radiobiological impact which increases the efficiency of patient treatment delivery. Alpha Tau Medical Ltd. (Tel Aviv, Israël) has developed a new brachytherapy method using radioactive seeds. The seeds called DaRT, for Diffusing alpha emitters Radiation Therapy, are composed of 224-Ra atoms which come from 228-Th generator. Currently, these seeds are characterized by an alpha-spectrometer and Geiger-Muller counter or well chamber for quality control. This project offers a new characterization of DaRT seeds using liquid scintillation. Liquid scintillation allows alpha and beta particles detection with the help of liquid cocktail and employing a scintillation counter. The characterization with liquid scintillation allows establishing and quantifying 228-Th trace contamination on the DaRT seeds. Also, it provides a method for seed quality control before they are used on patients by estimating their activity from spectrums established with the liquid scintillation counter. The spectrums obtained also give the possibility of dose estimation using either mass or mass stopping power in water. The results of the dose are compared to expected values from the literature and to simulations. / Le cancer est la première cause de mortalité au Canada. De nombreuses techniques de traitement du cancer existent utilisant la chimiothérapie, la chirurgie et la radiothérapie. En radiothérapie, les photons sont les rayonnements ionisants les plus fréquemment utilisés, cependant les particules alpha présentent des propriétés radiobiologiques intéressantes augmentant l'efficacité des résultats du traitement prodigué au patient. Une nouvelle technique de curiethérapie ayant recourt à des grains a été développée par Alpha Tau Medical Ltd.(Tel Aviv, Israël). Pour ce faire les grains appelés DaRT, pour Radiothérapie par émetteurs-alpha diffusant, sont constitués d'atomes 224-Ra issu d'un processus de fabrication à l'aide d'un générateur de 228-Th. Ces grains sont actuellement caractérisés par spectromètre-alpha et compteur Geiger-Muller ou chambre à puit dans le cas du contrôle de qualité. Ce projet vise à proposer une nouvelle caractérisation des grains DaRT en recourant à la scintillation liquide. La scintillation liquide permet la détection des particules alpha et beta à l'aide de liquide scintillant et d'un compteur de scintillation. La caractérisation des grains avec la scintillation liquide permet d'établir et de quantifier la présence de trace de contamination de 228-Th. Cette technique de mesure de la radioactivité donne aussi la possibilité de réaliser le contrôle de qualité des grains avant son utilisation sur les patients en évaluant l'activité de ces derniers à partir des spectres obtenus par le compteur de scintillation liquide. Les spectres obtenus offrent la réalisation d'une estimation de la dose soit par la masse soit par le pouvoir d'arrêt massique des alpha dans l'eau. Les résultats de la dose sont comparés à des valeurs attendues de la littérature et de simulation.
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