Application of the Kelly Criterion to Ornstein-Uhlenbeck Processes

In this paper, we study the Kelly criterion in the continuous time framework building on the work of E.O. Thorp and others. The existence of an optimal strategy is proven in a general setting and the corresponding optimal wealth process is found. A simple formula is provided for calculating the optimal portfolio for a set of price processes satisfying some simple conditions. Properties of the optimal investment strategy for assets governed by multiple Ornstein-Uhlenbeck processes are studied. The paper ends with a short discussion of the implications of these ideas for financial markets.Comment: presented at Complex'2009 (Shanghai, Feb. 23-25

Improved diffusion Monte Carlo for bosonic systems using time-step extrapolation "on the fly"

A diffusion Monte Carlo algorithm employing "on the fly" extrapolation with respect to the time step is implemented and demonstrated simulating realistic systems. Significant advantages are obtained when using on the fly extrapolation, leading to reduced systematic and statistical errors. The sound theoretical basis of extrapolation on the fly is discussed and compared to justifications for the a posteriori extrapolation

Changes in the Tracheal Ciliated Cells in Rabbits Treated by Cis-Diamminedichloroplatinum (II) as Studied by Electron Microscopy

The ciliated epithelium of the rabbit\u27s trachea was investigated after a single 5 mg dose of cis-diamminedichloroplatinum (cis-DDP). Specimens were taken for scanning electron microscopy, transmission electron microscopy and light microscopy. Examination was performed daily for 20 consecutive days. A cytotoxic effect of the drug on the ciliated epithelium was observed with bent ciliary tips, swollen tips and broken cilia. Finally the cilia were lost and large areas of the surface were covered with microvilli. However, 20 days after the drug injection, the restitution of the ciliary carpet was almost complete

The Effect of 10 and 20 Gy Single Dose Irradiation on the Esophageal Mucosa of the Rabbit. An Electron Microscopic Study

The mucosa of rabbit esophagus was irradiated with single doses of 10 and 20 Gy respectively. Specimens were taken for scanning electron microscopy (SEM), and light microscopy investigations. Examinations were made 1-14 days after 10 Gy and 1-17 days after 20 Gy. Irradiation resulted in edema during the first days. The thickness of the epithelium was at its lowest value around day 5 after the administration of 10 Gy, and on days eight to ten after the administration of 20 Gy. Damage of the epithelium surface, as scored on SEM micrographs, was most pronounced on days eight to eleven after irradiation, showing a clear dose dependency. The second week after irradiation repair was seen concluding in an overshoot of the mucosal height. The amount of bacteria on the surface increased during the period of edema, and decreased when the damage was most pronounced

Changes in the Esophageal Epithelium in Rabbits Treated by Cis-Dichlorodiammineplatinum as Studied by Electron Microscopy

The esophageal mucosa of the rabbit was investigated after a single dose of 5 mg Cis-Dichlorodiammineplatinum (Cis-DDP). Specimens were taken for scanning electron microscopy, transmission electron microscopy, and light microscopy. Examination was performed daily for 20 consecutive days. A cytotoxic effect was observed already the first day after injection with an intracellular oedema. Thereafter the height of the esophageal epithelium and the basal cell layer steadily decreased to a minimum day 11. This parallels the damaged microridges and an increased cell loss as revealed by scanning electron microscopy. At the end of the observation period the esophageal mucosa had completely restituted

Internal Migration and Regional Population Dynamics in Europe: Sweden Case Study

This paper describes the structure of internal migration and population change in Sweden in recent decades, focussing on the years 1988 and 1998 to capture change in the last decade. Up to the 1970s and again in the early 1990s natural increase play an important role in regional population dynamics. In the late 1990s growing international migration, decreasing fertility and strong net internal migration into large cities increased the importance of migration at both national and local levels. In 1988 migration flows contributed to a pattern of relatively even deconcentration of population. Urban centres and surrounding communities experienced mixed patterns of growth. The pattern observed in 1998 was entirely different. It showed a strong movement up the urban hierarchy. Rural and remote areas, especially those in Norrland, depopulated. In 1998 migrants moved from low-density areas to high-density. High density areas had much higher population gains than low density over the 1988–1998 period. There is a difference in migration pattern between the north of the country, which mostly loses population and the central and southern parts, which mostly gain people. The pattern of migration of the Swedish population is, to large extent, related to the level of unemployment. Low unemployment areas attract migrants; high unemployment areas lose them. However, the level of unemployment cannot be considered in isolation, because the level of unemployment is correlated with the level of urbanisation and with type of regional economy. Areas with an educated population have a very strong attraction for migrants. A high level of education is indispensable for high level services, including tertiary education, and for high technology enterprises, which attract migrants. Young people migrate to metropolitan areas and university towns out of the other types of municipality. Medium sized municipalities attract families. Outflows from industrial regions and Inner Norrland municipalities are visible in all age groups. Metropolitan areas are gaining popularity among families. The elderly population migrates to university and medium size municipalities

Ciliated Cells of the Trachea of the Rabbit, Treated with Cis-Diamminedichloroplatinum (II) Alone, or in Combination with Ionizing Radiation

The ciliated epithelium of the rabbit trachea was irradiated with daily fractions of 2 Gy to an accumulated dose of 20 Gy (TD: 2, 6, 10, 16, or 20 Gy). Fifteen to forty-five minutes before start of the first irradiation ( treatment day 1) , 5 mg cis-DDP was given by intraperitoneal injection to each rabbit. Examination was made 1-10 days after each fractionation schedule, when specimens were ta ken for investigations. Scanning electron microscope investigations showed a gradual development of ciliary damage from blebs on the cilia to swollen tips, broken and bent cilia and finally an epithelial lining with areas free from cilia with a surface covered with microvilli-like structures. SEM also showed cell loss, and remnants of dead cells on the surface together with detritus. By transmission electron microscope ciliary damage, cell death and cell loss of the ciliated cell layer as well as exfoliation of portions of goblet-like cells on the surface could be confirmed. The irradiated ciliated epithelium and the untreated control epithelium in each animal showed no difference in this respect. Thus no enhancement of the effects of radiation could be observed. The development of ultrastructural damage may be due to a cytotoxic effect of the drug on the ciliated epithelium. However, 19 days after the start of cis-DDP injection, a hyperplasia of the basal cell layer was observed, which indicates that the observed cytotoxicity of the drug is reversible and a normalisation occurs during the last days of observation in this study

Effects of Cis-Dichlorodiammineplatinum Alone and in Combination with Ionizing Radiation on the Esophageal Mucosa: A Scanning and Transmission Electron Microscopic Study

Cis-dichlorodiammineplatinum (cis-DDP) has for more than 20 years been part of the therapeutic arsenal of oncology. Most of the knowledge about its biological action is based on clinical investigations and therefore an examination of the influence of cis-DDP at the cellular and sub-cellular level is necessary. Five mg of cis-DDP was given intraperitoneally (i.p.) to ten rabbits. Ultrastructural examinations were performed on the upper and lower parts of the esophagus each day after the injection on the following ten days. Another 50 rabbits were given 5 mg cis-DDP and were irradiated in an area just beneath the hypopharynx. They were given 2 Gy at each irradiation and were maximally treated with up to 20 Gy. Examinations were carried out from the first day after the final treatment and each day during ten consecutive days. Five animals were used as controls. Cis-DDP proved to have a deleterious effect on the epithelial layer of the esophageal mucosa with cell loss and structural disarrangement of the microridges and whorls on the surface. This finding was an early phenomenon and lasted for all ten examination days. The changes were not more exaggerated when irradiation was added to the experiments. Repopulation of new cells from the matrix was noticed about five days after the administration of cis-DDP alone

Improved diffusion Monte Carlo propagators for bosonic systems using Ito calculus

The construction of importance sampled diffusion Monte Carlo (DMC) schemes accurate to second order in the time step is discussed. A central aspect in obtaining efficient second order schemes is the numerical solution of the stochastic differential equation (SDE) associated with the Fokker-Plank equation responsible for the importance sampling procedure. In this work, stochastic predictor-corrector schemes solving the SDE and consistent with It\uf4 calculus are used in DMC simulations of helium clusters. These schemes are numerically compared with alternative algorithms obtained by splitting the Fokker-Plank operator, an approach that we analyze using the analytical tools provided by It\uf4 calculus. The numerical results show that predictor-corrector methods are indeed accurate to second order in the time step and that they present a smaller time step bias and a better efficiency than second order split-operator derived schemes when computing ensemble averages for bosonic systems. The possible extension of the predictor-corrector methods to higher orders is also discussed

Effects of Fractionated Irradiation on the Esophageal Mucosa: A Scanning and Transmission Electron Microscopic Study

The mucosa of rabbit esophagus was irradiated with daily fractions of 2 Gy to an accumulated dose of 20 Gy. Specimens were taken for scanning electron microscopy, transmission electron microscopy and light microscopy investigations. Examination was made 1-10 days after each fractionation schedule. Light microscopy showed dose-dependent edema of the irradiated mucosa which also could be seen and scored from SEM pictures. SEM investigations showed that this was accompanied by loosening of microridges and a slightly increased cell loss. By SEM, a varying amount of bacteria could be seen which did not make intimate contact with the surface cells. During the first five days there was a steady decrease of the number of bacteria in relation to the absorbed dose. In the later period of examination, the amount of bacteria increased up to a given dose of 10 Gy. Thereafter, the number faded off to about zero when 20 Gy had been administered