580 research outputs found
Analysis of service failures within the Austrian fashion retailing - online and offline
No full textAuthor Simon Thalhammer, LL.BMasterarbeit Johannes Kepler Universität Linz 2025Arbeit auf den öffentlichen PCs in den Bibliotheken der JKU+Medizin abrufba
Inhibition by lectins of glutamate receptor desensitization is determined by the lectin's sugar specificity at kainate but not AMPA receptors
No full textHigh-order time-splitting Hermite and Fourier spectral methods
No full textIn this paper, we are concerned with the numerical solution of the time-dependent Gross-Pitaevskii Equation (GPE) involving a quasi-harmonic potential. Primarily, we consider discretisations that are based on spectral methods in space and higher-order exponential operator splitting methods in time. The resulting methods are favourable in view of accuracy and efficiency; moreover, geometric properties of the equation such as particle number and energy conservation are well captured. Regarding the spatial discretisation of the GPE, we consider two approaches. In the unbounded domain, we employ a spectral decomposition of the solution into Hermite basis functions: on the other hand. restricting the equation to a sufficiently large bounded domain, Fourier techniques are applicable. For the time integration of the GPE, we study various exponential operator splitting methods of convergence orders two, four, and six. Our main objective is to provide accuracy and efficiency comparisons of exponential operator splitting Fourier and Hermite pseudospectral methods for the time evolution of the GPE. Furthermore, we illustrate the effectiveness of higher-order time-splitting methods compared to standard integrators in a long-term integration
Combined acoustic and optical trapping
No full textCombining several methods for contact free micro-manipulation of small particles such as cells or micro-organisms provides the advantages of each method in a single setup. Optical tweezers, which employ focused laser beams, offer very precise and selective handling of single particles. On the other hand, acoustic trapping with wavelengths of about 1 mm allows the simultaneous trapping of many, comparatively large particles. With conventional approaches it is difficult to fully employ the strengths of each method due to the different experimental requirements. Here we present the combined optical and acoustic trapping of motile micro-organisms in a microfluidic environment, utilizing optical macro-tweezers, which offer a large field of view and working distance of several millimeters and therefore match the typical range of acoustic trapping. We characterize the acoustic trapping forces with the help of optically trapped particles and present several applications of the combined optical and acoustic trapping, such as manipulation of large (75 ?m) particles and active particle sorting.© 2011 OSA<br/
The sugar specificity of lectins affects their influence on the desensitization of glutamate receptor current responses
No full text
A minimisation approach for computing the ground state of Gross–Pitaevskii systems
No full textIn this paper, we present a minimisation method for computing the ground stateof systems of coupled Gross–Pitaevskii equations. Our approach relies on a spectral decomposition of the solution into Hermite basis functions. Inserting the spectral representation into the energy functional yields a constrained nonlinear minimisation problem for the coefficients. For its numerical solution, we employ a Newton-like method with an approximate line-search strategy. We analyse this method and prove global convergence. Appropriate starting values for the minimisation process are determined by a standard continuation strategy. Numerical examples with two and three-component two-dimensional condensates are included. These experiments demonstrate the reliability of our method and nicely illustrate the effect of phase segregation
A desensitization-inhibiting mutation in the glutamate binding site of rat alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor subunits is dominant in heteromultimeric complexes
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