4,768 research outputs found
Structural stability in an African context
No full textStructural Stability is a particular focus for reconceptualising developmental strategy and development aid and has provoked unfore-seen responses in the course of a recent, mainly German debate. This debate began late in 2000 when a number of prominent German scholars in African Studies initiated a policy dialogue through a widely circulated and publicly discussed "Afrika Memorandum" centred on the notion of structural stability. Its arguments are relevant not only to a German audience but offer stimulating and thought-provoking inputs into the debate in the wider European context on bilateral and multilateral relations with Africa. This Discussion Paper presents the revised contributions to a Consulta- tive Workshop on Structural Stability in an African Context that took place at the Nordic Africa Institute in Uppsala on 31 March and 1 April 2003.CONTENTS -- Economic Aspects of the African CrisisLow-Level Equilibria, Traps and Structural Instability/Robert Kappel -- Comments on Robert Kappel/Anders Danielson -- "Structural Stability"-A Leitmotiv for African Policies? Background and Ambition/Andreas Mehler -- The New Partnership for Africa's Development (NePAD) -- A Step Towards Structural Stability?/Henning Melbe
Resonant double-grating waveguide structures as inverted Fabry-Perot interferometers
No full textA multiple-interference model to describe double-grating waveguide structures is presented. It is based on the multiple-interference model for single-grating waveguide structures previously established by Friesem and co-workers [J. Opt. Soc. Am. A 14, 2985 (1997)]. We show that double grating waveguide structures, in particular, as well as the usual single-grating waveguide structures can be completely described by our model and that explicit dependences of the resonant conditions on the wavelength, the angle, and the polarization of the incident light as well as on system parameters such as refractive indices, layer thickness, grating depths, and grating period can be given. This multiple-interference model elucidates the resonance behavior of single- and double-grating waveguide structures and predicts reflection and transmission resonance bandwidths in analogy to those of the classic Fabry-Perot interferometer. One can explain and understand the periodicity of resonances by interpreting grating waveguide structures as inverted Fabry-Perot interferometers. Comparison with exact numerical calculations and verification by experimental investigations prove the model to be a powerful tool for design purposes and to provide a deep understanding of the observed resonance phenomena. (C) 2004 Optical Society of America
Stylos kai edraiōma tēs ekklēsias, sive, Dissertatio de iustificatione hominis
No full textquam ... sub praesidio ... Ioh. Henrici Heideggeri ... placido eruditorum examini subiicit Andreas Steinerus, Vitod. author & respondens, ad diem Octobris loco horisque solitisDiss. Hohe Schule Zürich, 167
Double grating waveguide structures: 350-fold enhancement of two-photon fluorescence applying ultrashort pulses
No full textThe enhancement of ultrashort pulse excited two-photon fluorescence (TPF) based on resonant double grating waveguide structures (DGWS) was studied systematically. For a specific wavelength, polarisation and angular orientation, the transmission of the incident light through these devices vanishes while most of the light is reflected by the structure. Since these resonances are based on a guided mode phenomenon they exhibit a large evanescent field inducing enormous TPF signals of, for instance, marker or biomolecules at the waveguide surface. TPF signals for various concentrations of Rhodamine B under and out of resonance conditions were recorded. We demonstrate a resonance enhancement of the monitored TPF of more than two orders of magnitude which can be achieved by DGWS specifically designed for ultrashort pulses without beam focussing or laser amplification. Furthermore, the observed enhancement increases with decreasing dye molecule concentration at the surface, so these structures can be considered as powerful platforms for TPF detection of even very small amounts of fluorescent molecules in biotechnology and spectroscopic applications. (c) 2004 Elsevier B.V. All rights reserved
Author: Andreas Johannis Prytz
No full textAn edition of the consecration sermons in Gothenburg Cathedral 1633 by Superintendent Andreas Johannis Prytz, with introductory comments. The first sermon deals with the need for Church buildings, the second with the consecration of a new Church
We must combine conservation of nature with benefits to society. Interview by Gaby Allheilig with Andreas Heinimann on IPBES' Global Assessment Report on Biodiversity and Ecosystem Services
No full textOn 6 May 2019, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) presented its report on the state of biodiversity and ecosystem services worldwide. The first such assessment since 2005, it concludes that biodiversity and ecosystem loss has reached the point where it threatens human well-being. The researchers involved recommend several urgent measures to political decision-makers. Andreas Heinimann of CDE was the one Swiss scientist who worked as a lead author on a chapter of the report
To athanaton tēs psychēs, sive, Dissertatio de animae immortalitate, ex naturae & sanae rationis lumine demonstrata
No full textquam ... sub praesidio ... Iohannis Lavateri ... publicae ac placidae disquisitioni submittit Andreas Steinerus, Vitod. author & respondens ...Dedikation an Johannes Lavater, Jacob Meyer, Joh. Jacob Schaedler und Jacob Hegner auf dem Titelbl. versoDiss. Hohe Schule Zürich, 167
Family Virtues and Social Critique: Andreas Latzko’s Anti-War Prose (1917-1918)
No full textBetween 1917 and 1918, the Austro-Hungarian author Andreas Latzko (1876-1943) wrote three separate publications against the Great War: Menschen im Krieg (1917), Friedensgericht (1918), and Der letzte Mann (published 1919). Literary historians tend to bypass these works, and the few who note them chiefly focus on the best-selling novella cycle Menschen im Krieg (1917). It is usually presented as an example of expressionist political prose, or as a mixture of social satire and aesthetic shock-tactics that chiefly remains indebted to realist traditions, albeit with occasional incursions into expressionistic styles..
Picosecond-pulse-induced two-photon fluorescence enhancement in biological material by application of grating waveguide structures
No full textWe report enhancement of two-photon fluorescence (TPF) excitation in fluorescent dyes and fluorescently labeled biomolecules by exploiting the optical properties of double grating waveguide structures (DGWSs). Picosecond laser pulses generate a large evanescent field based on the guided mode phenomenon in the resonant DGWSs, which induces strong TPF signals from fluorescent dyes at the waveguide surface. By recording enhanced TPF signals of Rhodamine B and Lucifer Yellow under resonance conditions, a detection sensitivity of concentrations of approximately one dye molecule per 0.1 mu m(2) was achieved. For the first time to our knowledge, enhanced TPF signals of a Lucifer Yellow-labeled biomolecule (human self-peptide) in an aqueous environment are demonstrated. These results strongly encourage the use of DGWSs as enhancement platforms in modern biophysics and biotechnology for investigations of biological membranes and cells. (c) 2005 Optical Society of America
Giant enhancement of two-photon fluorescence induced by resonant double grating waveguide structures
No full textWe report a 350-fold enhancement of ultra-short-pulse-excited two-photon fluorescence (TPF) using a resonant double grating waveguide structure (DGWS). These structures show vanishing transmission and maximum reflection under resonance conditions, i.e. specific wavelength, polarisation and angular orientation of the incident light. This guided mode phenomenon is characterised by a large field enhancement inducing an enormous TPF signal of fluorescent molecules at the waveguide surface, as compared to direct non-resonant excitation. We demonstrate that high spectral acceptance for ultra-short pulses with broad spectral bandwidths can be achieved by a specifically designed DGWS, and that neither beam focussing nor high laser power is necessary for TPF excitation. Due to the high enhancement of more than two orders of magnitude, DGWS can be considered as a powerful platform for TPF applications such as biosensing and microarray technology
- …
