Notes on drift theory

It is shown that there is a simpler way to derive the average guiding center drift of a distribution of particles than via the so-called single particle analysis. Based on this derivation it is shown that the entire drift formalism can be considerably simplified, and that results for low order anisotropies are more generally valid than is usually appreciated. This drift analysis leads to a natural alternative derivation of the drift velocity along a neutral sheet

JCMmode: An Adaptive Finite Element Solver for the Computation of Leaky Modes

We present our simulation tool JCMmode for calculating propagating modes of an optical waveguide. As ansatz functions we use higher order, vectorial elements (Nedelec elements, edge elements). Further we construct transparent boundary conditions to deal with leaky modes even for problems with inhomogeneous exterior domains as for integrated hollow core Arrow waveguides. We have implemented an error estimator which steers the adaptive mesh refinement. This allows the precise computation of singularities near the metal's corner of a Plasmon-Polariton waveguide even for irregular shaped metal films on a standard personal computer.Comment: 11 page

The mineralization of commercial organic fertilizers at 8°C temperature

In organic production only organic fertilizers and soil conditioners can be used to supply the soil with nitrogen. The mineralization of these products is slow and so there can be problems with the supply of nitrogen, when the demand of the plants is high. The supply of nitrogen from organic products depends on the speed of their mineralization which is primarily influenced by the composition and formulation of their raw material. In apple production in the Alps-region especially during spring problems with nitrogen supply are common. In that period, the weather conditions are sometimes bad, the temperature in the soil is low and mineralization starts slowly - apple trees demand more nitrogen than the soil can deliver. To compensate the demand of the apple tree organic growers can not use mineral fertilizers but only organic fertilizers and soil conditioners whose mineralization rate is often unknown. There is a strong need in organic fruit production to receive more information about the behaviour of fertilizers in the soil especially concerning their N-release under different conditions. To acquire that information, incubation experiments under controlled conditions (temperature, type of soil, humidity of the soil) were carried out in the laboratory to determine the mineralization-rate of different organic fertilizers and soil conditioners which are available in our region

Kinematic analysis of handwriting movements in patients with Alzheimer's disease, mild cognitive impairment, depression and healthy subjects

A variety of studies have demonstrated that motor disorders, parkinsonism and extrapyramidal motor symptoms (EPMS) are common in patients with Alzheimer's disease (AD). Several studies have reported an association of EPMS with severity, progression and poor prognosis of AD. The majority of these studies used clinical assessments for the rating of EPMS. In this study, kinematic handwriting analysis was used to quantify differences in fine hand motor function in patients with probable AD and mild cognitive impairment (MCl, as an assumed initial stage of AD) compared to depressed patients and healthy controls. Both patients with MCl and patients with probable AD exhibited loss of fine motor performance. Movements of AD patients were significantly less regular than those of healthy controls. Copyright (C) 2003 S. Karger AG, Basel

Numerical Investigation of Light Scattering off Split-Ring Resonators

Recently, split ring-resonators (SRR's) have been realized experimentally in the near infrared (NIR) and optical regime. In this contribution we numerically investigate light propagation through an array of metallic SRR's in the NIR and optical regime and compare our results to experimental results. We find numerical solutions to the time-harmonic Maxwell's equations by using advanced finite-element-methods (FEM). The geometry of the problem is discretized with unstructured tetrahedral meshes. Higher order, vectorial elements (edge elements) are used as ansatz functions. Transparent boundary conditions and periodic boundary conditions are implemented, which allow to treat light scattering problems off periodic structures. This simulation tool enables us to obtain transmission and reflection spectra of plane waves which are incident onto the SRR array under arbitrary angles of incidence, with arbitrary polarization, and with arbitrary wavelength-dependencies of the permittivity tensor. We compare the computed spectra to experimental results and investigate resonances of the system.Comment: 9 pages, 8 figures (see original publication for images with a better resolution