A continuous time random walk model for financial distributions

We apply the formalism of the continuous time random walk to the study of financial data. The entire distribution of prices can be obtained once two auxiliary densities are known. These are the probability densities for the pausing time between successive jumps and the corresponding probability density for the magnitude of a jump. We have applied the formalism to data on the US dollar/Deutsche Mark future exchange, finding good agreement between theory and the observed data.Comment: 14 pages, 5 figures, revtex4, submitted for publicatio

Overall survival results of a trial assessing patient-reported outcomes for symptom monitoring during routine cancer treatment

Symptoms are common among patients receiving treatment for advanced cancers, yet are undetected by clinicians up to half the time. There is growing interest in integrating electronic patient-reported outcomes (PROs) into routine oncology practice for symptom monitoring, but evidence demonstrating clinical benefit has been limited

Generation-by-Generation Dissection of the Response Function in Long Memory Epidemic Processes

In a number of natural and social systems, the response to an exogenous shock relaxes back to the average level according to a long-memory kernel $\sim 1/t^{1+\theta}$ with $0 \leq \theta <1$. In the presence of an epidemic-like process of triggered shocks developing in a cascade of generations at or close to criticality, this "bare" kernel is renormalized into an even slower decaying response function $\sim 1/t^{1-\theta}$. Surprisingly, this means that the shorter the memory of the bare kernel (the larger $1+\theta$), the longer the memory of the response function (the smaller $1-\theta$). Here, we present a detailed investigation of this paradoxical behavior based on a generation-by-generation decomposition of the total response function, the use of Laplace transforms and of "anomalous" scaling arguments. The paradox is explained by the fact that the number of triggered generations grows anomalously with time at $\sim t^\theta$ so that the contributions of active generations up to time $t$ more than compensate the shorter memory associated with a larger exponent $\theta$. This anomalous scaling results fundamentally from the property that the expected waiting time is infinite for $0 \leq \theta \leq 1$. The techniques developed here are also applied to the case $\theta >1$ and we find in this case that the total renormalized response is a {\bf constant} for $t < 1/(1-n)$ followed by a cross-over to $\sim 1/t^{1+\theta}$ for $t \gg 1/(1-n)$.Comment: 27 pages, 4 figure

Atrial rhythm during ventricular fibrillation in the dog

Depolarization of the atrioventricular junctional tissues and of the atrial septum was examined in the perfused dog heart before and during ventricular fibrillation by (I) recording the potentials from the junctional tissues in the regions of the interatrial and interventricular septum and examining the relationship of activity at these sites to atrial depolarization, (2) computing histograms and autocorrelograms of atrial firing intervals to study atrial rhythmicity, and (3) plotting the sequence of atrial septal depolarization. The junctional tissue was gene rally randomly depolarized by the fibrillating ventricles. The histograms and autocorrelograms indicate that during ventricular fibrillation the atrial depolarization intervals do not remain constant, but vary widely. This seems to be due to the retrograde excitation from the junctional tissues. Plots of the depolarization sequences of the interatrial septum also indicate that retrograde depolarization takes place. The junctional tissues decrease the number of impulses that can pass from ventric1e to atrium,and they similarly decrease the number of impulses that pass in an antegrade direction during atrial fibrillation

Atrial rhythm during ventricular fibrillation in the dog

Depolarization of the atrioventricular junctional tissues and of the atrial septum was examined in the perfused dog heart before and during ventricular fibrillation by (I) recording the potentials from the junctional tissues in the regions of the interatrial and interventricular septum and examining the relationship of activity at these sites to atrial depolarization, (2) computing histograms and autocorrelograms of atrial firing intervals to study atrial rhythmicity, and (3) plotting the sequence of atrial septal depolarization. The junctional tissue was gene rally randomly depolarized by the fibrillating ventricles. The histograms and autocorrelograms indicate that during ventricular fibrillation the atrial depolarization intervals do not remain constant, but vary widely. This seems to be due to the retrograde excitation from the junctional tissues. Plots of the depolarization sequences of the interatrial septum also indicate that retrograde depolarization takes place. The junctional tissues decrease the number of impulses that can pass from ventric1e to atrium,and they similarly decrease the number of impulses that pass in an antegrade direction during atrial fibrillation

In vitro interactions between probiotic bacteria and milk proteins probed by atomic force microscopy

International audienceInteractions between microbial cells and milk proteins are important for cell location into dairy matrices. In this study, interactions between two probiotic strains, Lactobacillus rhamnosus GG and Lactobacillus rhamnosus GR-1, and milk proteins (micellar casein, native and denatured whey proteins) were studied. The bacterial surface characterization was realized with X-ray photoelectron spectroscopy (XPS) to evaluate surface composition (in terms of proteins, polysaccharides and lipid-like compounds) and electrophoretic mobility that provide information on surface charge of both bacteria and proteins along the 3-7 pH range. In addition, atomic force microscopy (AFM) enabled the identification of specific interactions between bacteria and whey proteins, in contrast to the observed nonspecific interactions with micellar casein. These specific events appeared to be more important for the GG strain than for the GR-1 strain, showing that matrix interaction is strain-specific. Furthermore, our study highlighted that in addition to the nature of the strains, many other factors influence the bacterial interaction with dairy matrix including the nature of the proteins and the pH of the media