Qualitative Mediennutzungsforschung: Offline- und Online-Methoden im Vergleich

Während quantitative Onlinebefragungen heute bereits zum Standard in Wissenschaft und Marktforschung gehören, gilt die qualitative Online-Forschung in den Sozialwissenschaften und insbesondere in der Kommunikationswissenschaft dagegen immer noch als relatives Neuland. Weshalb zögert die akademische Forschung bei der Verwendung qualitativer Online-Methoden? Auf den ersten Blick scheinen die Ziele der qualitativen Forschung (Suche nach Sinn und Handlungsmustern) im Widerspruch mit den Kennzeichen der computervermittelten Kommunikation (visuelle Anonymität, Unverbindlichkeit, Oberflächlichkeit) zu stehen. Ziel der Masterarbeit ist es, anhand eines Vergleichs qualitativer Online- und Offline-Methoden, die Vor- und Nachteile synchroner Online-Verfahren aufzuzeigen und daraus abzuleiten, was bei der Durchführung von qualitativen Online-Befragungen zu beachten ist. Diese Studie will schließlich dazu ermuntern online zu forschen, um das Potential qualitativer Online-Methoden nutzen zu können

A scaling rule for power output of salt hydrate tablets for thermochemical energy storage

Salt hydrates are thermochemical materials capable of storing and releasing heat through reversible reaction with water vapor. In a heat battery, salt hydrate tablets of millimeter size are necessary to ensure a sufficient permeability of the packed bed. A profound understanding of the hydration process of these tablets is required to improve their kinetic performance. In this study we show that the hydration timescale of salt tablets is transport limited and that it depends primarily on the porosity and on the driving force (Δp). From gravimetric measurements done on SrBr2·6H2O and CaC2O4 we derived the intrinsic reaction and effective diffusion coefficients (k and Deff) and found that they validate a front-diffusion limited hydration hypothesis. In particular, the obtained Deff values (0.8–4.5 mm2 s−1) only depend on the tablets' porosities. Based on these parameters, we calculated the second Damköhler number (DaII) and proved that many other hydration reactions are diffusion limited. In the case of identical structures, the power output is therefore controlled only by the driving force. Its variation could be predicted by calculation of a so-called power scaling factor (Λ) for a selection of salts. This power scaling factor depends on the enthalpy (ΔH) and entropy (ΔS) of the reaction. For a temperature output of 40 °C and at 12 mbar most hydration reactions fall in the interval 0&lt;Λ&lt;30 and Λ exceeds 30 only in very few cases. This parameter establishes therefore another important constraint to the selection of the most ideal salt. Suitable strategies to circumvent the diffusion limitation will lead to the development of next generation salt hydrate tablets for thermochemical energy storage.</p

Persistent Wnt/β-catenin signaling determines dorsalization of the postnatal subventricular zone and neural Stem cell specification into oligodendrocytes and glutamatergic neurons

In the postnatal and adult central nervous system (CNS), the subventricular zone (SVZ) of the forebrain is the main source of neural stem cells (NSCs) that generate olfactory neurons and oligodendrocytes (OLs), the myelinating cells of the CNS. Here, we provide evidence of a primary role for canonical Wnt/β-catenin signaling in regulating NSC fate along neuronal and oligodendroglial lineages in the postnatal SVZ. Our findings demonstrate that glutamatergic neuronal precursors (NPs) and oligodendrocyte precursors (OPs) are derived strictly from the dorsal SVZ (dSVZ) microdomain under the control of Wnt/β-catenin, whereas GABAergic NPs are derived mainly from the lateral SVZ (lSVZ) microdomain independent of Wnt/β-catenin. Transcript analysis of microdissected SVZ microdomains revealed that canonical Wnt/β-catenin signaling was more pronounced in the dSVZ microdomain. This was confirmed using the β-catenin-activated Wnt-reporter mouse and by pharmacological stimulation of Wnt/β-catenin by infusion of the specific glycogen synthase kinase 3β inhibitor, AR-A014418, which profoundly increased the generation of cycling cells. In vivo genetic/pharmacological stimulation or inhibition of Wnt/β-catenin, respectively, increased and decreased the differentiation of dSVZ-NSCs into glutamatergic NPs, and had a converse effect on GABAergic NPs. Activation of Wnt/β-catenin dramatically stimulated the generation of OPs, but its inhibition had no effect, indicating other factors act in concert with Wnt/β-catenin to fine tune oligodendrogliogenesis in the postnatal dSVZ. These results demonstrate a role for Wnt/β-catenin signaling within the dorsal microdomain of the postnatal SVZ, in regulating the genesis of glutamatergic neurons and OLs

Introduction

This thematic issue of Comparativ examines the relationship between place and cultural encounters in conceptual as well as empirical respect. The introduction delineates the discussions revolving around the concepts of place, space, and encounter. It proposes a reappraisal of the concept of place, which had almost been pushed off the agenda by the spatial turn and globalisation debates. The authors of the introduction and of the other thematic contributions argue for a perspective on place which connects spatial configurations and practices of encounter, understanding places as products of social, material, and conceptual relations. In doing so, they take up theoretical reflections about the relationality of place or space as put forward by Tim Ingold (in social anthropology), Doreen Massey (in geography) or Karl Schlögel (in history). All of their approaches emphasize that places are formed in relational processes, often spanning across time and space. In this sense, places are not mere stages or contexts for events of encounter but are being constituted by them. From such a perspective, the room for manoeuvre, which opens up through interaction, becomes apparent: Neither identities nor (hi-) stories are inalterably bound to pre-existing places, but they are just as dynamic as the relations forming particular sites. The&nbsp;great diversity of (cultural) encounters only emerges jointly with the respective places of interaction. Such lines of thought also allow for new approaches to past and current forms of global connections and mobility. In this sense the contributions united in this interdisciplinary thematic issue examine case (or: place) studies from the 17th century up to the present. Grounded in historiographical, literary- and religious-studies scholarship, they undertake to further refine the process-oriented perspective presented in the introduction

Chronic stress experience in young physicians: impact of person- and workplace-related factors

Objectives: The objectives of the present study are to investigate and compare the relative impact of workplace-related factors and personal characteristics on chronic psychosocial stress experience in young physicians. Methods: In a prospective study, a cohort of Swiss medical school graduates was followed up, beginning in 2001. In their fourth and eighth year after graduation, 443 physicians assessed their workplace conditions, the experienced effort-reward imbalance, the received professional and emotional support as well as their personal characteristics. The chronic stress experience was measured by the Trier Inventory for the Assessment of Chronic Stress-Screening Subscale of Chronic Stress (TICS-SCSS), 7years after graduation. The model of influencing factors on chronic stress experience was tested with a hierarchical regression analysis. Results: The mean in chronic stress (TICS-SCSS) in our study sample is significantly higher (p<0.001) compared to an age-matched population representative sample. In the prediction of chronic stress, the workplace-related factor effort-reward imbalance as well as the personal characteristic overcommitment turned out to be the most important risk factors. Stress protective are high satisfaction with career support, sense of coherence and occupational self-efficacy. The whole set of variables used in the regression model explains 51% of the variance of chronic stress experience. In the prediction of chronic stress, gender has no significant moderator effect. Conclusions: It is a matter of concern that young physicians report to feel chronically stressed early in their professional career. Actions have to be taken to reduce the stress level mainly in regard to re-establish reciprocity between perceived effort invested and rewards received, in the form of esteem, monetary gain and career opportunities including job securit

Conceptualizing sustainable consumption: toward an integrative framework

Consumption and sustainability are complex issues—they cannot be reduced to the choice of consumer goods or to “green consumption.” Doing so would neglect the multifaceted embeddedness of consumer acts and the multidimensionality of sustainability. To understand patterns of consumption and move them toward sustainability means dealing with this double complexity. A coherent reference framework is therefore needed, to enable locating and correlating research questions, theories, and findings. Such a framework should provide a basis for interdisciplinary under-standing, mutual acknowledgment, and collaborative knowledge creation. Therefore, it needs to be the result of an integrative approach; otherwise it would not allow a wide variety of disciplines to work with it. This article presents such a framework, developed in the course of an interdisciplinary process in a research program. In this process, the researchers of the focal topic asked four questions: 1) How can consumption be conceptualized? 2) How can consumption and sustainability be related? 3) How can sustainable consumption be assessed? and 4) How can changes to individual consumption be motivated? The article condenses the researchers’ overall answers to these questions into four complementary core statements capturing the key elements of the reference framework and concludes by sketching the framework’s benefits for future research