Serial intravascular ultrasound assessment of coronary atherosclerosis progression and remodeling

Cardiovascular disease is a major cause of morbidity and mortality in countries with western lifestyle. Reliable quantitative assessment of the extent of coronary atherosclerosis during the natural history of coronary artery disease and following therapeutic interventions is important to evaluate disease progression and antiatherosclerotic therapies. Coronary angiography visualizes the luminal silhouette but not the vessel wall where the atherosclerotic disease process is actually located. Intravascular ultrasound (IVUS), however, provides transmural tomographic images of the coronary artery and direct measurements of lumen, plaque, and vessel dimensions. Serial IVUS measurements allow to quantify the extent of coronary plaque progression or regression and changes in total vessel dimensions (remodeling process) as introduced in Chapter 1. The Chapters 2-4 of this thesis focus on the relation between serum parameters and progression-regression of coronary atherosclerosis in the left main stem as assessed with serial IVUS. In addition, Chapter 5 explores the relation between the risk of cardiovascular events and IVUS assessed plaque progression-regression. The Chapters 6-8 investigate the remodeling behaviour of coronary lesions in a serial IVUS design by providing (1) evidence of serial remodeling (Chapter 6), (2) the validation of the non-serial assessment of coronary remodeling (Chapter 7), and (3) the validation of Glagov's histopathological remodeling hypothesis. Chapter 9 assesses measurement differences between different IVUS devices in vitro and validated dedicated calibration formulas for correction. Chapter 10 focuses on volumetric radiofrequency-based IVUS analysis of atherosclerotic plaque composition and evaluates the reproducibility of this technique for the use in studies with a serial design. Finally, Chapter 11 reviews the current knowledge of coronary atherosclerosis that was been gained from observational and randomized pharmacological intervention trials with serial IVUS

Distribution of diameters for Erd\"os-R\'enyi random graphs

We study the distribution of diameters d of Erd\"os-R\'enyi random graphs with average connectivity c. The diameter d is the maximum among all shortest distances between pairs of nodes in a graph and an important quantity for all dynamic processes taking place on graphs. Here we study the distribution P(d) numerically for various values of c, in the non-percolating and the percolating regime. Using large-deviations techniques, we are able to reach small probabilities like 10^{-100} which allow us to obtain the distribution over basically the full range of the support, for graphs up to N=1000 nodes. For values c<1, our results are in good agreement with analytical results, proving the reliability of our numerical approach. For c>1 the distribution is more complex and no complete analytical results are available. For this parameter range, P(d) exhibits an inflection point, which we found to be related to a structural change of the graphs. For all values of c, we determined the finite-size rate function Phi(d/N) and were able to extrapolate numerically to N->infinity, indicating that the large deviation principle holds.Comment: 9 figure

The equity premium puzzle and emotional asset pricing

Since the equity premium as well as the risk-free rate puzzle question the concepts central to financial and economic modeling, we apply behavioral decision theory to asset pricing in view of solving these puzzles. U.S. stock market data for the period 1960-2003 and German stock market data for the period 1977-2003 show that emotional investors who act in accordance to Bell's (1985) disappointment theory - a special case of prospect theory − and additionally administer mental accounts demand a high equity premium. Furthermore, these investors reason a low risk-free rate. However, Barberis/Huang/Santos (2001) already showed that limited rational investors demand a high equity premium. But as opposed to them, our approach additionally supports dividend smoothing. --Behavioral Finance,Equity Premium Puzzle,CCAPM,Dividend Smoothing

Behavioral dividend policy

In this paper we develop an optimal dividend policy in the presence of limited rational inves-tors. Concretely, investors with mental accounts for dividends and stock prices as well as emotions like disappointment and elation embody the limited rationality. Furthermore, investors evaluate changes in wealth instead of final wealth. A management maximizing investors' modified utility results in the optimality of dividend payments as well as dividend smoothing, which both have long been puz-zles to financial theorists. Moreover, a model specification leads to a gradual dividend adjustment to changes in net earnings as described by Lintner (1956). --dividend policy,dividend smoothing,behavioral finance

The equity premium puzzle and emotional asset pricing

Since the equity premium as well as the risk-free rate puzzle question the concepts central to financial and economic modeling, we apply behavioral decision theory to asset pricing in view of solving these puzzles. U.S. stock market data for the period 1960-2003 and German stock market data for the period 1977-2003 show that emotional investors who act in accordance to Bell's (1985) disappointment theory - a special case of prospect theory &#x2212; and additionally administer mental accounts demand a high equity premium. Furthermore, these investors reason a low risk-free rate. However, Barberis/Huang/Santos (2001) already showed that limited rational investors demand a high equity premium. But as opposed to them, our approach additionally supports dividend smoothing

Behavioral dividend policy

In this paper we develop an optimal dividend policy in the presence of limited rational inves-tors. Concretely, investors with mental accounts for dividends and stock prices as well as emotions like disappointment and elation embody the limited rationality. Furthermore, investors evaluate changes in wealth instead of final wealth. A management maximizing investors' modified utility results in the optimality of dividend payments as well as dividend smoothing, which both have long been puz-zles to financial theorists. Moreover, a model specification leads to a gradual dividend adjustment to changes in net earnings as described by Lintner (1956)

Behavioral dividend policy

"In this paper we develop an optimal dividend policy in the presence of limited rational inves-tors. Concretely, investors with mental accounts for dividends and stock prices as well as emotions like disappointment and elation embody the limited rationality. Furthermore, investors evaluate changes in wealth instead of final wealth. A management maximizing investors’ ‘modified’ utility results in the optimality of dividend payments as well as dividend smoothing, which both have long been puz-zles to financial theorists. Moreover, a model specification leads to a gradual dividend adjustment to changes in net earnings as described by Lintner (1956)." (author's abstract

Gründungsfinanzierung und beschränkte Rationalität

In dem vorliegenden Beitrag wird erörtert, wie beschränkte Rationalität auf verschiedene Phasen der Gründungsfinanzierung einwirken kann. Dabei wird konkret die Venture Capital-Finanzierung als wohl bedeutendste Form einer Gründungsfinanzierung der Untersuchung zugrunde gelegt. Für diese Finanzierungsform werden zunächst empirische Sachverhalte und typische Abläufe vorgestellt, um auf dieser Basis realiter zu beobachtende Verhaltensmuster zweier an Venture Capital-Finanzierungen beteiligter Gruppen herauszuarbeiten: die Gruppe der Venture Capital-Geber (VC-Geber) und die Gruppe der Investoren, die nachfolgend die Unternehmensteile von den Venture Capi-tal-Gebern übernehmen (Investoren). Um grundsätzlich Erklärungsansätze beschränkter Rationalität nutzen zu können, werden ferner wichtige Elemente der Behavioral Finance dargestellt, wobei insbe-sondere die auf Kahneman u. Tversky zurückgehende Prospect-Theorie Berücksichtigung findet. Über den Einbezug dieser Elemente gelingt es, beobachtbare Verhaltensmuster sowohl für die Gruppe der VC-Geber als auch für die Gruppe der Investoren zu begründen. --Gründungsfinanzierung,Venture Capital,Behavioral Finance,beschränkte Rationalität

Towards computing low-makespan solutions for multi-arm multi-task planning problems

We propose an approach to find low-makespan solutions to multi-robot multi-task planning problems in environments where robots block each other from completing tasks simultaneously. We introduce a formulation of the problem that allows for an approach based on greedy descent with random restarts for generation of the task assignment and task sequence. We then use a multi-agent path planner to evaluate the makespan of a given assignment and sequence. The planner decomposes the problem into multiple simple subproblems that only contain a single robots and a single task, and can thus be solved quickly to produce a solution for a fixed task sequence. The solutions to the subproblems are then combined to form a valid solution to the original problem. We showcase the approach on robotic stippling and robotic bin picking with up to 4 robot arms. The makespan of the solutions found by our algorithm are up to 30% lower compared to a greedy approach.Comment: Workshop for Planning and Robotics (PlanRob), International Conference on Automated Planning and Scheduling (ICAPS), 202