Bibliographische Beschreibung: Christian Dick „Schützen Impfungen vor der Entstehung von Allergien?“ Universität Leipzig, Dissertation 68 S., 72 Lit., 9 Abb., 19 Tab., 7 Anlagen. Referat: Die Anzahl von Kindern mit allergischen Erkrankungen steigt in den industrialisierten Staaten dieser Welt stetig. Nach der „Hygiene-Hypothese“ ist dafür ein moderner „westlicher“ Lebensstil mitverantwortlich. Dieser führt dazu, dass Menschen einer immer geringeren Anzahl von Infektionen und mikrobiellen Expositionen ausgesetzt sind. Diese scheinen jedoch gerade in den ersten Lebensjahren ein wichtiges Stimulans des Immunsystems darzustellen. Die Folge davon scheint eine Imbalance zwischen T1- und T2-Helferzellen zu sein, welche zu einem verstärkten Auftreten von allergischen Erkrankungen führt. Entsprechend dieser „Hygiene-Hypothese“ könnten im Umkehrschluss Impfungen im frühen Kindesalter als eine Art „Ersatzinfektion“ einen protektiven Effekt auf allergische Erkrankungen besitzen. Anhand der Daten einer prospektiven Geburtskohortenstudie mit einer Anfangsteilnehmerzahl von 3097 Kindern wurde zum Ende des 6. Lebensjahres die Lebenszeitprävalenz des atopischen Ekzems von geimpften und nicht geimpften Kindern verglichen. Der Vergleich wurde zum einen für drei unterschiedliche Impfungen -Tetanus, Haemophilus influenzae b und Masern- einzeln durchgeführt. Zum anderen wurden Kinder mit einem hohen Impfstatus, welche drei Mal als erfolgreich geimpft gewertet wurden, Kindern mit niedrigem Impfstatus gegenübergestellt, die nur einmal oder gar nicht als erfolgreich geimpft gewertet wurden. Für keine der drei einzeln untersuchten Impfungen konnte ein signifikanter Einfluss auf die Ekzemlebenszeitprävalenz zum Ende des 6. Lebensjahrs festgestellt werden. Dagegen erwies sich ein hoher Impfstatus als protektiver Faktor in Bezug auf die Ekzemlebenszeitprävalenz zum vollendeten 6. Lebensjahr (OR=0,29, 95% Konfidenzintervall=0,12 - 0,71 /p=0,006). Ergebnis dieser Arbeit ist, dass sich ein hoher Impfstatus protektiv auf die Allergieentwicklung auswirkt. Damit stützen die Ergebnisse die „Hygiene-Hypothese“.

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In this thesis, we present an introduction to Wald’s Sequential Probability Ratio Test (SPRT) for binary outcomes. Previous researchers have investigated ways to modify the stopping boundaries that reduce the expected sample size for the test. In this research, we investigate ways to further improve these boundaries. For a given maximum allowable sample size, we develop a method intended to generate all possible sets of boundaries. We then find the one set of boundaries that minimizes the maximum expected sample size while still preserving the nominal error rates. Once the satisfying boundaries have been created, we present the results of simulation studies conducted on these boundaries as a means for analyzing both the expected number of observations and the amount of variability in the sample size required to make a decision in the test.

Concern is mounting over the increase in prevalence and severity of overweight and obesity in children worldwide. Intrauterine life has been identified as a critical period for the development of overweight or obesity and other related chronic diseases. Prenatal exposure to maternal cigarette smoke (PEMCS) has consistently emerged as an important risk factor for excess weight in the offspring and is a targetable behaviour for prevention strategies. This study examines first the relationship between PEMCS and overweight status of children at 10 years of age and second, whether PEMCS is associated with distinct longitudinal BMI trajectories. Analyses include multivariate and multinomial logistic regression and longitudinal group based modeling methods. PEMCS was found to be a significant risk factor for overweight in children independent of birth weight and catch-up growth. However, PEMCS was not associated with BMI trajectory membership. Our results lend support to the paradigm of in-utero excess weight prevention.

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The Double Deficit Hypothesis posits that four mutually exclusive subgroups can be identified in a reading disabled (RD) sample. These subgroups are predicted to differ on reading measures, and further evidence suggests they may differ on other academic achievement (AA) and neuropsychological (NP) measures, as well as sex ratios and rate of ADHD diagnosis. Two hundred twenty six college-level adults identified as RD were evaluated, and subgroup comparisons were analyzed. Significant subgroup differences were observed in each domain. No subgroup differences were observed for sex or ADHD diagnosis. Findings suggest that patterns of linguistic ability affect the profiles of reading, AA, and NP performance that characterize adults with RD. These findings have implications for evaluations and academic accommodations.

Background A common goal for many investors is to beat the market. However, only a few are able to do so consistently over a long time. The random walk theory and the efficient market hypothesis are two widely accepted theories that state that it should not be possible to consistently generate abnormal returns in an efficient market. There are though some contradicting results that argue against market efficiency and a lot of those studies have value investment in common. Joseph Piotroski was in 2000 able to generate a value investment model that consistently beat the market between the years 1976-1996. Purpose The purpose of this paper is to test Piotroski’s model on stock markets with different size and maturity to evaluate if the model, as an investment strategy, can generate a better risk adjusted rate of return than a comparable market index. Unlike recent studies done on Piotroski’s value investing model, we will add a number of additional comparison portfolios and use two different valuation models to determine the source of return variation. Method This thesis employed a quantitative research method with a deductive approach. With data from four markets with different characteristics regarding efficiency and development, we performed an ex-ante test from 1995 to 2009. By employing Piotroski’s model, each stock on the four markets was given a score from 0-9; a portfolio for each market was created by the stocks that received a score of 8-9. They were then compared with portfolios from the same market based on the small firm- and book-to-market anomaly. We also performed a test between the markets to see if Piotroski’s model worked better in low efficiency or developed countries. All portfolios in this thesis were risk-adjusted with two different models, CAPM and the Fama & French three-factor model. Since these models use various factors to risk-adjust we have tested if they generate a different valuation of the same portfolio. Results Our study has shown that Piotroski’s model is not able to generate significant abnormal returns compared to our portfolios based on anomalies, our results also give an indication that by removing the anomaly premium the model might be destroying value instead of creating it. An explanation to why the model works in Piotroski’s study and not in ours could be the different method of risk adjustment. Piotroski uses a simple method by deducting the market return while we use two models that are taking additional factors into account. Our results are also able to show that choice of the valuation model does have a significant effect on the risk-adjusted return and could therefore affect the end-results of a study. Last of all our results do not give any support for the hypothesis that Piotroski’s model works better in countries with low efficiency compared to high efficiency or in countries that are developed compared to emerging.

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<p>This thesis analyzes the differences in monetary return when saving in stocks using Individual Pension Saving (IPS) or saving directly on the stock exchange (OMX). An individual is assumed to have the same portfolio of stocks whether he or she uses IPS or OMX. Different length of saving years, payment years, real rates of return, saving amounts and different tax rates are compared to each other between the systems. The results indicate a clear benefit using IPS in the long run, when tax rates are higher during the saving period compared to when retrieving the payment. It also indicates an uncertain usefulness of IPS compared to OMX when individuals have only income tax when saving and retrieving payment. In some cases using IPS can generate a monetary loss compared to OMX. Individuals that are low-income earners and prefers a low risk in their investments should not use IPS, while high-income earners that prefer high risk investments should use IPS instead of directly investing on the OMX.</p> / <p>Den här uppsatsen analyserar skillnaderna i avkastning om man sparar i aktier när man använder sig av Individuellt pensionssparande (IPS) eller sparar direkt på börsen (OMX). En individ antas inneha samma aktieportfölj vare sig han eller hon nyttjar IPS eller OMX. Olika längd av sparande, utbetalning, olika realavkastningar, olika sparnivåer och olika skattesatser jämförs med varandra i de olika systemen. Resultaten indikerar en klar fördel för användandet av IPS på lång sikt, när skattesatsen vid sparandet överskrider skattesatsen vid erhållandet av betalningen. Det finns också indikationer på osäkerhet vad gäller nyttan av att använda IPS jämfört med OMX när individer endast har inkomstskatt både vid sparandet och vid erhållandet av betalningen. I vissa fall kan individen förlora på att nyttja IPS jämfört med OMX. Individer som är låginkomsttagare och föredrar låg risk på sina investeringar skall ej använda sig av IPS, medan höginkomsttagare som föredrar högrisk på sina investeringar skall använda IPS istället för OMX.</p>

Thesis (Ph. D.)--University of California, San Diego, 2002. / Vita. Includes bibliographical references (leaves 149-152).