Der konstruktionistische Ansatz in der nordamerikanischen Problemsoziologie: Fallstudien als Beitrag zur Weiterentwicklung der Theorie?

'In den beiden letzten Jahrzehnten dominiert in der nordamerikanischen theoretischen und empirischen Forschung über soziale Probleme der konstruktionistische Ansatz. Aus der konsequenten Durchführung seiner zentralen theoretischen und methodologischen Ideen folgt der Sachverhalt, daß nahezu ausschließlich Einzelfallstudien über Konstruktionsprozesse sozialer Probleme durchgeführt werden. Gegen diese Strategie wenden die Vertreter einer objektivistischen Position ein, daß eine solche auf den Einzelfall abstellende Forschungsstrategie nicht in der Lage sein kann, die Grundlagen für eine allgemeinere Theoriebildung zu schaffen. Eine erste systematische Sichtung neuerer Fallstudien zeigt, daß tatsächlich in den Einzelfallstudien und ihren Interpretationen durch die Autoren selbst wenig für eine umfassende Theoriebildung geleistet wird. Auf der anderen Seite könnte die vergleichende Analyse von Einzelfallstudien durchaus zur Grundlage neuerer Theoriebildung und zur Überprüfung von umfassenderen Hypothesen werden.' (Autorenreferat)'For almost two decades anglo-american theories and empirical social research on social problems have been dominated by the constructionist perspective. A consequent application of its central theoretical and methodological principles leads to a very rigid concentration on case studies about processes on constructing social problems. Proponents of an 'objetivistic' approach to the study of social problems argue that a strategy that restricts itself on case studies will not be able to lay the ground for general theories of social problems. A first systematic analysis of case studies reported in the last years comes to the result that these case studies and their interpretations by the authors really do not result in a notable theoretical progress. On the other hand, a comparative analysis of case studies may become a stimulus for generating new theoretical ideas and a chance to test propositions about the contingencies of the processes of constructing social problems.' (author's abstract)

Electrical tuning of the oscillator strength in type II InAs/GaInSb quantum wells for active region of passively mode-locked interband cascade lasers

This project has received funding from the European Commission's Horizon 2020 Research and Innovation Programme iCspec under grant agreement No. 636930 and has also been supported by the National Science Centre of Poland within Grant No. 2014/15/B/ST7/04663.Two designs of active region for an interband cascade laser, based on double or triple GaInSb/InAs type II quantum wells (QWs), were compared with respect to passive mode-locked operation in the mid-infrared range around 4 µm. The layer structure and electron and hole wavefunctions under external electric field were engineered to allow controlling the optical transition oscillator strength and the resulting lifetimes. As a result, the investigated structures can mimic absorber-like and gain-like sections of a mode-locked device when properly polarized with opposite bias. A significantly larger oscillator strength tuning range for triple QWs was experimentally verified by Fourier-transform photoreflectance.Publisher PDFPeer reviewe

Interband cascade laser arrays for simultaneous and selective analysis of C1-C5 hydrocarbons in the petrochemical industry

Funding: European Union Horizon 2020 research and innovation programme under grant agreement No 636930 (iCspec).The detection and measurement of hydrocarbons is of high interest for a variety of applications, for example within the oil & gas industry from extraction throughout the complete refining process, as well as for environmental monitoring and for portable safety devices. This paper presents a highly sensitive, selective and robust tunable laser analyzer that has the capability to analyze several components in a gas sample stream. More specifically, a multi-gas system for simultaneous detection of C1 to iC5 hydrocarbons, using a room temperature distributed feedback interband cascade laser array, emitting in the 3.3 micrometer band has been realized. It combines all the advantages of the tunable laser spectroscopy method for a fast, sensitive and selective in-line multicomponent tunable laser analyzer. Capable of continuous and milliseconds fast monitoring of C1-iC5 hydrocarbon compositions in a process stream, the analyzer requires no consumables (e.g. purging, carrier gas) and no in-field calibration, enabling a low cost of ownership for the analyzer. The system was built, based on an industrial GasEye series platform and deployed for the first time in field at Preem refinery in Lysekil, Sweden in autumn 2018. Results of the measurement campaign and comparison with gas chromatography instrumentation is presented.PostprintPeer reviewe

Bathymetric Mapping Of The Seafloor - A German Contribution To Completing The Map By 2030, Cruise No. MSM88/1 + MSM88/2, November 28, 2019 - January 14, 2020, Mindelo (Cabo Verde) - Mindelo (Cabo Verde) - Bridgetown (Barbados)

Despite over 100 years of acoustic seabed mapping, only around 15% of the seafloor has ever been directly mapped and little of the mapping performed has been systematic or over larger areas. The result is that our knowledge of seafloor structure is rudimentary and our understanding of the processes which form them has, in principle, advanced little since the advent of plate tectonics. Societally, the seafloor plays a vital role in humanity’s "life support system", for example providing habitat for marine organisms, stimulating mixing of ocean water as part of the overturning circulation system and increasingly being the site of industrial installations. It is scientifically and societally imperative that we bring the level of knowledge of the surface of our planet up to that of bodies like Moon and Mars that are mapped with a resolution better than 100 m per pixel. It is also essential that the data are made freely available to all to support research and conservation. The aim of this cruise was to map previously uncharted part of the tropical Atlantic using the ship’s multibeam system and to provide the data to global open databases as well as to acquire magnetic gradient data along the same tracks. Magnetic anomalies from so-called Oceanic Core Complexes challenged the conventional view that marine magnetic anomalies arose in the upper, extrusive layer of the oceanic crust, because the crust has been stripped away at these complexes. We therefore collected magnetic data simultaneously to the multibeam data in order to constrain the interpretation of the observed seabed morphology

Monolithic frequency comb platform based on interband cascade lasers and detectors

Funding: Austrian Science Fund (FWF) within the projects "NanoPlas" (P28914-N27), "Building Solidsfor Function" (Project W1243), "NextLite" (F4909-N23), as well as by the Austrian Research Promotion Agency through the ERA-Net Photonic Sensing program, project "ATMO-SENSE" (FFG:861581). H.D. was supported by the ESF project CZ.02.2.69/0.00.0/16_027/0008371. A.M.A was supported by the projects COMTERA - FFG 849614 and AFOSR FA9550-17-1-0340.New insights into the laser dynamics of interband cascade lasers reveal the possibility to generatefrequency modulated combs by utilizing their inherent gain nonlinearity. The resultingcomb state is characterized by chirped instantaneous frequency, which appears to be universalto frequency combs based on gain induced four-wave mixing. The fast dynamics in the injectorsfurther allow the realization of exceptionally sensitive and high-speed photodetectors,operating at room-temperature, using the very same epilayer structure. With the capability ofintegrating frequency combs and ultra-fast detectors on a single chip consuming less than awatt of electric power, interband cascade laser technology provides a complete and unmatchedplatform for future monolithic and battery-driven dual-comb spectrometers.Publisher PDFPeer reviewe

Picosecond pulses from a mid-infrared interband cascade laser

Funding: Austrian Science Fund (F4909-N23, P28914-N27,W1243); Österreichische Forschungsförderungsgesellschaft (ATMO-SENSE, ERANet Photonic Sensing program, COMTERA-FFG849614); European Science Foundation (ESF) (CZ.02.2.69/0.0/0.0/16_027/0008371); Air Force Office of Scientific Research(AFOSR FA9550-17-1-0340).The generation of mid-infrared pulses in monolithic and electrically pumped devices is of great interest for mobile spectroscopic instruments. The gain dynamics of interband cascade lasers (ICL) are promising for mode-locked operation at low threshold currents. Here, we present conclusive evidence for the generation of picosecond pulses in ICLs via active mode-locking. At small modulation power, the ICL operates in a linearly chirped frequency comb regime characterized by strong frequency modulation. Upon increasing the modulation amplitude, the chirp decreases until broad pulses are formed. Careful tuning of the modulation frequency minimizes the remaining chirp and leads to the generation of 3.2 ps pulses.Publisher PDFPeer reviewe

Subjective Cognitive Complaints in Participants of the Healthy Brain Ageing Study (HeBA)

Subjective cognitive complaints (SCC) have the potential for earlier detection of Alzheimer’s disease and Parkinson’s disease. Currently, the results of the completed online survey in the frame of the HeBA study reveal that 23% of the Luxembourgish participants have SCC with the SCC group having a higher prevalence rate of depression

Symptomatic cerebral oedema during treatment of diabetic ketoacidosis: effect of adjuvant octreotide infusion

<p>Abstract</p> <p>Introduction</p> <p>A potentially lethal complication of diabetic ketoacidosis (DKA) in children is brain oedema, whether caused by DKA itself or by the therapeutic infusion of insulin and fluids.</p> <p>Case presentation</p> <p>A 10-year old previously healthy boy with DKA became unconscious and apnoeic due to cerebral oedema (confirmed by abnormal EEG and CT-scan) during treatment with intravenous fluids (36 ml/h) and insulin (0.1 units/kg/h). He was intubated and artificially ventilated, without impact on EEG and CT-scan. Subsequently, adjuvant infusion of octreotide was applied (3.5 μg/kg/h), suppressing growth hormone (GH) and IGF-1 production and necessitating the insulin dose to be reduced to 0.05 - 0.025 units/kg/h. The brain oedema improved and the boy made a full recovery.</p> <p>Conclusion</p> <p>Co-therapy with octreotide was associated with a favourable outcome in the present patient with DKA and cerebral oedema. Whether this could be ascribed to the effects of octreotide on the insulin requirement or on the GH/IGF-axis remains to be elucidated.</p