In this work, the transition between regular and irregular patterns was studied in reaction-diffusion (RD) systems with the ability of pattern formation. The focus of this work lies on the role of the coupling conditions between two or more oscillators for the occurrence of the irregular states and the…
Today, computer simulations form an integral part of many research and
development efforts. The scope of what can be modeled has increased
dramatically, as computing performance improved over the last two decades.
But with serial-execution performance of CPUs leveling off, future
performance increases…
The present work makes a contribution to the statistical analysis of
medical time series. In particular, the work discusses the possibility of
detecting the rate of fibrillation – observed in the atrium during atrial
fibrillation - based solely on the statistical properties of ventricular
interbeat-intervals.
First…
Atrial fibrillation is the most important arrhythmia in clinical practice, accounting for one third of hospitalisations for cardiac disrhythms. Although it is known since the beginning of the last century, the underlying mechanisms are still under disucssion. In this work two proposed mechanisms are…
Magnetic resonance imaging allows to determine the blood oxygenation
level of small venous vessels or the blood capillary network by
evaluating the magnetic resonance signal acquired with multi-echo
gradient-echo sequences. The signal formation of a voxel traversed by
a vein or interspersed with capillaries…
The statistical properties of ventricular (RR) interbeat intervals during atrial fibrillation exhibit several characteristic features, such as a linear relation between the local mean and standard deviation obtained in small time windows (constant signal to noise ratio), a crossover in the power spectrum…
Atrial fibrillation is commonly described by irregular electrical excitations circulating in the atria. Developing methods to characterise and classify various kinds of atrial fibrillation is an important task, since it allows one to improve the diagnosis and
to support the choice of suitable therapies.…
Abstract of the PhD Thesis
"long-wavelength magnons and phonons and
rotonlike excitations in amorphous solids"
by Dipl.-Phys. Rolf Öttking from Minden (Westf.)
Extended inhomogeneities and variations of the nearest-neighbour
distances are a characteristic common property of amorphous solids.
Essential…