Sonification of autonomic rhythms in the frequency spectrum of heart rate variability

Presented at the 12th International Conference on Auditory Display (ICAD), London, UK, June 20-23, 2006.This poster presents some of the work currently being done at the Paracelsus Clinic in Switzerland on heart rate variability biofeedback with a real time auditory display. Heart rate variability biofeedback is an important diagnostic and therapeutic tool in the work with a wide variety of chronic disorders. We use a proprietary building-block type laboratory computer program that is linked via MIDI to a software sequencer with a VST virtual instrument library. Beyond the sonification of RR intervals as discrete numbers, the development of new techniques became necessary in order to be able to sonify the dynamic, wave-like structure of autonomic rhythms in the frequency spectrum of HRV, what we call ''heartmusic''. The fact that patients can hear their inner autonomic activity as music in real time and so work with elements of their own autonomous rhythmic oscillations, may also add an important new dimension to this field in the future

Spatio-temporal dispersion of Aedes taeniorhynchus in Florida

Aedes taeniorhynchus is normally associated in high numbers with salt marshes along coastal areas in North, Central and South America. It has the potential to be a critical vector of important human and animal arboviruses. St. Louis encephalitis, Everglades, and West Nile viruses have been isolated from it in Florida, and can transmit epizootic strains of Venezuelan equine encephalomyelitis, eastern equine encephalitis, and Rift Valley fever viruses in the lab. To better identify the threat from these viruses we are attempting to better understand the spatio-temporal patterns of Aedes taeniorhynchus in Florid

A Probabilistic Analysis of Kademlia Networks

Kademlia is currently the most widely used searching algorithm in P2P (peer-to-peer) networks. This work studies an essential question about Kademlia from a mathematical perspective: how long does it take to locate a node in the network? To answer it, we introduce a random graph K and study how many steps are needed to locate a given vertex in K using Kademlia's algorithm, which we call the routing time. Two slightly different versions of K are studied. In the first one, vertices of K are labelled with fixed IDs. In the second one, vertices are assumed to have randomly selected IDs. In both cases, we show that the routing time is about c*log(n), where n is the number of nodes in the network and c is an explicitly described constant.Comment: ISAAC 201

Formation of phase lags at the cyclotron energies in the pulse profiles of magnetized, accreting neutron stars

Context: Accretion-powered X-ray pulsars show highly energy-dependent and complex pulse-profile morphologies. Significant deviations from the average pulse profile can appear, in particular close to the cyclotron line energies. These deviations can be described as energy-dependent phase lags, that is, as energy-dependent shifts of main features in the pulse profile. Aims: Using a numerical study we explore the effect of cyclotron resonant scattering on observable, energy-resolved pulse profiles. Methods: We generated the observable emission as a function of spin phase, using Monte Carlo simulations for cyclotron resonant scattering and a numerical ray-tracing routine accounting for general relativistic light-bending effects on the intrinsic emission from the accretion columns. Results: We find strong changes in the pulse profile coincident with the cyclotron line energies. Features in the pulse profile vary strongly with respect to the average pulse profile with the observing geometry and shift and smear out in energy additionally when assuming a non-static plasma. Conclusions: We demonstrate how phase lags at the cyclotron energies arise as a consequence of the effects of angular redistribution of X-rays by cyclotron resonance scattering in a strong magnetic field combined with relativistic effects. We also show that phase lags are strongly dependent on the accretion geometry. These intrinsic effects will in principle allow us to constrain a system's accretion geometry.Comment: 4 pages, 4 figures; updated reference lis

Cyclotron resonant scattering feature simulations. I. Thermally averaged cyclotron scattering cross sections, mean free photon-path tables, and electron momentum sampling

Electron cyclotron resonant scattering features (CRSFs) are observed as absorption-like lines in the spectra of X-ray pulsars. A significant fraction of the computing time for Monte Carlo simulations of these quantum mechanical features is spent on the calculation of the mean free path for each individual photon before scattering, since it involves a complex numerical integration over the scattering cross section and the (thermal) velocity distribution of the scattering electrons. We aim to numerically calculate interpolation tables which can be used in CRSF simulations to sample the mean free path of the scattering photon and the momentum of the scattering electron. The tables also contain all the information required for sampling the scattering electron's final spin. The tables were calculated using an adaptive Simpson integration scheme. The energy and angle grids were refined until a prescribed accuracy is reached. The tables are used by our simulation code to produce artificial CRSF spectra. The electron momenta sampled during these simulations were analyzed and justified using theoretically determined boundaries. We present a complete set of tables suited for mean free path calculations of Monte Carlo simulations of the cyclotron scattering process for conditions expected in typical X-ray pulsar accretion columns (0.01<B/B_{crit}<=0.12, where B_{crit}=4.413x10^{13} G and 3keV<=kT<15keV). The sampling of the tables is chosen such that the results have an estimated relative error of at most 1/15 for all points in the grid. The tables are available online at http://www.sternwarte.uni-erlangen.de/research/cyclo.Comment: A&A, in pres

Technology transfer of dynamic IT outsourcing requires security measures in SLAs

For the present efforts in dynamic IT outsourcing environments like Grid or Cloud computing security and trust are ongoing issues. SLAs are a proved remedy to build up trust in outsourcing relations. Therefore, it is necessary to determine whether SLAs can improve trust from the perspective of the outsourcing customer by integration of security measures. The conducted survey indicates that customers see SLAs as an approach to increase their level of trust in IT outsourcing partners. In addition, security measures in SLAs are of high relevance to support trust but not yet integrated appropriately. However, SLAs are very important for the technology transfer of eScience projects in Grid computing. Again, Grid based outsourcing of biomedical IT services requires security measures in SLAs. Thus, the technology transfer process of dynamic IT outsourcing infrastructures requires adequate SLAs in order to be successful

Added value of second biopsy target in screen-detected widespread suspicious breast calcifications

Introduction: There is controversy on the optimal work‐up of screen‐detected widespread breast calcifications: whether to biopsy a single target or multiple targets. This study evaluates agreement between multiple biopsy targets within the same screen‐detected widespread (≥25 mm) breast calcification to determine if the second biopsy adds value. Methods: Retrospective observational study of women screened in a statewide general population risk breast cancer mammographic screening program from 2009 to 2016. Screening episodes recalled for widespread calcifications where further views indicated biopsy, and two or more separate target areas were sampled within the same lesion were included. Percentage agreement and Cohen\u27s Kappa were calculated. Results: A total of 293317 women were screened during 761124 separate episodes with recalls for widespread calcifications in 2355 episodes. In 171 women, a second target was biopsied within the same lesion. In 149 (86%) cases, the second target biopsy result agreed with the first biopsy (κ = 0.6768). Agreement increased with increasing mammography score (85%, 86% and 92% for score 3, 4 and 5 lesions). Same day multiple biopsied lesions were three times more likely to yield concordant results compared to post‐hoc second target biopsy cases. Conclusion: While a single target biopsy is sufficient to discriminate a benign vs. malignant diagnosis in most cases, in 14% there is added value in performing a second target biopsy. Biopsies performed prospectively are more likely to yield concordant results compared to post‐hoc second target biopsy cases, suggesting a single prospective biopsy may be sufficient when results are radiological‐pathological concordant; discordance still requires repeat sampling