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Dem Text liegt ein Vortrag zugrunde, der auf dem 31. Motivationspsychologischen Kolloquium (MPK) in Heidelberg 2015 gehalten wurde. Im ersten Teil bietet er einen Überblick über die Motivationsforschung am Bochumer Heckhausen-Lehrstuhl in den 70er-Jahren („Bochumer Schule“). Dabei werden neben Heinz Heckhausen einzelne Mitarbeiter und ihre Schwerpunkte vorgestellt sowie das stimulierende Arbeitsklima an diesem Lehrstuhl beschrieben. Entsprechend der Vortragseinladung wird im Anschluss die Entwicklung der eigenen Forschungsschwerpunkte skizziert. Noch unter Heckhausens Leitung waren dies zunächst die Forschung zur Bezugsnormorientierung und die Einzelfallanalysen zur Lernmotivation mit dem Erweiterten Kognitiven Motivationsmodell. Danach geht der Vortrag auf Forschungsthemen ein, die dann in Heidelberg und Potsdam dazukamen. Hier geht es um die Erforschung von Tätigkeitsanreizen und um das Flow-Erleben. Abschließend wird der Potsdamer Versuch skizziert, herauszufinden, auf welche Weise unterschiedliche Motivationsqualitäten den Lernprozess und seine Resultate beeinflussen.
The invasion success of the cyanobacterium Cylindrospermopsis raciborskii in experimental mesocosms
(2017)
The potentially toxic, invasive cyanobacterium Cylindrospermopsis raciborskii, originating from sub-tropical regions, has spread into temperate climate zones in almost all continents. Potential factors in its success are temperature, light and nutrient levels. Grazing losses through zooplankton have been measured in the laboratory but are typically not regarded as a factor in (failed) invasion success. In some potentially suitable lakes, C. raciborskii has never been found, although it is present in water bodies close by. Therefore, we tested the invasive potential of three different isolates introduced into natural plankton communities using laboratory mesocosm experiments under three grazing levels: ambient zooplankton densities, removal of large species using 100 mu m mesh and a ca. doubling of large species. Three C. raciborskii isolates originating from the same geographic region (North-East Germany) were added separately to the four replicates of each treatment and kept in semi-continuous cultures for 21 days. Two isolates disappeared from the mesocosms and were also not viable in filtered lake water indicating that the lake water itself or the switch from culture medium to lake water led to the decay of the inoculated C. raciborskii. Only one out of the three isolates persisted in the plankton communities at a rather low level and only in the treatment without larger zooplankton. This result demonstrates that under potentially suitable environmental conditions, top-down control from zooplankton might hamper the establishment of C. raciborskii. Non-metric multidimensional scaling showed distinct variation in resident phytoplankton communities between the different grazing levels, thus differential grazing impact shaped the resident community in different ways allowing C. raciborskii only to invade under competitive (= low grazing pressure) conditions. Furthermore, even after invasion failure, the temporary presence of C. raciborskii influenced the phytoplankton community.
Due to increasing pressure on estuarine marshes from sea level rise and river training, there is a growing need to understand how species-environment relationships influence the zonation and growth of tidal marsh vegetation. In the present study, we investigated the distribution and stand characteristics of the two key brackish marsh species Bolboschoenus maritimus and Phragmites australis in the Elbe estuary together with several abiotic habitat factors. We then tested the effect of these habitat factors on plant growth and zonation with generalised linear models (GLMs). Our study provides detailed information on the importance of single habitat factors and their interactions for controlling the distribution patterns and stand characteristics of two key marsh species. Our results suggest that flow velocity is the main factor influencing species distribution and stand characteristics and together with soil-water salinity even affects the inundation tolerance of the two specie investigated here. Additionally, inundation height and duration as well as interspecific competition helped explain the distribution patterns and stand characteristics. By identifying the drivers of marsh zonation and stand characteristics and quantifying their effects, this study provides useful information for evaluating a future contribution of tidal marsh vegetation to ecosystem-based shore protection.
Much of the literature in the field of international relations is currently concerned with the changing patterns of authority in world politics. This is particularly evident in the policy domain of climate change, where a number of authors have observed a relocation of authority in global climate governance. These scholars claim that multilateral treaty making has lost much of its spark, and they emphasize the emergence of transnational governance arrangements, such as city networks, private certification schemes, and business self-regulation. However, the different types of interactions between the various transnational climate initiatives and the intergovernmental level have not been studied in much detail and only recently attracted growing scholarly interest. Therefore, the present article addresses this issue and focuses on the interplay between three different transnational climate governance arrangements and the international climate regime. The analysis in this article underscores that substate and nonstate actors have attained several authoritative functions in global climate policy making. Nevertheless, the three case studies also demonstrate that this development does not imply that we are witnessing a general shift of authority away from the intergovernmental level toward transnational actors. Instead, what can be observed in global climate governance is an ongoing reconfiguration of authority, which apparently reaffirms the centrality of the international climate regime. Thus, this article points to the need for a more nuanced perspective on the changing patterns of authority in global climate governance. In a nutshell, this study shows that the international climate regime is not the only location where the problem of climate change is addressed, while it highlights the persistent authority of state-based forms of regulation.
Narratives of Belonging
(2017)
Die Darstellungen genealogischer Netzwerke waren in der Antike Ausdruck der Weltsicht ihrer Erzähler, mit deren Hilfe Nähe und Distanz zwischen verschiedenen Gruppen und Völkern ausgedrückt und hergestellt werden konnte. Auch Paulus bedient sich genealogischer Argumente, um die Beziehung nicht-jüdischer Christus-Gläubiger zu Israel und ihrem Gott zu verdeutlichen. Es handelt sich um eine ethnozentrische Argumentation, deren Fokus aber gleichzeitig eindeutig theozentrisch ist.
Using a standard repeated measures model with arbitrary true score distribution and normal error variables, we present some fundamental closed-form results which explicitly indicate the conditions under which regression effects towards (RTM) and away from the mean are expected. Specifically, we show that for skewed and bimodal distributions many or even most cases will show a regression effect that is in expectation away from the mean, or that is not just towards but actually beyond the mean. We illustrate our results in quantitative detail with typical examples from experimental and biometric applications, which exhibit a clear regression away from the mean (‘egression from the mean’) signature. We aim not to repeal cautionary advice against potential RTM effects, but to present a balanced view of regression effects, based on a clear identification of the conditions governing the form that regression effects take in repeated measures designs.
The past two decades have witnessed widespread scholarly interest in the role of cities in climate policy-making. This research has considerably improved our understanding of the local level in the global response to climate change. The present article synthesizes the literature on local climate policies with respect to the 1.5 degrees C target. While most studies have focused on pioneering cities and networks, we contend that the broader impacts of local climate actions and their relationship to regional, national, and international policy frameworks have not been studied in enough detail. Against this backdrop, we introduce the concept of upscaling and contend that local climate initiatives must go hand in hand with higher-level policies and be better integrated into the multi-level governance system.
Circumstantial evidence suggests that magnetism and enhanced X-ray emission are likely correlated in early B-type stars: similar fractions of them (similar to 10%) are strong and hard X-ray sources and possess strong magnetic fields. It is also known that some B-type stars have spots on their surface. Yet up to now no X-ray activity associated with spots on early-type stars was detected. In this Letter we report the detection of a magnetic field on the B2V star rho Oph A. Previously, we assessed that the X-ray activity of this star is associated with a surface spot, herewith we establish its magnetic origin. We analyze spectra of rho Oph A obtained with the FORS2 spectrograph at ESO Very Large Telescope (VLT) at two epochs, and detect a longitudinal component of the magnetic field of the order of similar to 500 G in one of the datasets. The detection of the magnetic field only at one epoch can be explained by stellar rotation which is also invoked to explain observed periodic X-ray activity. From archival HARPS ESO VLT high resolution spectra we derived the fundamental stellar parameters of rho Oph A and further constrained its age. We conclude that rho Oph A provides strong evidence for the presence of active X-ray emitting regions on young magnetized early type stars.
To purchase or not?
(2017)
Although ecologically and socially responsible consumption helps to reduce the harmful effects of resource use for both nature and society, all types of consumption (whether green or fair) deplete valuable resources. At the same time, to maintain household financial sustainability, spending should not exceed a household's financial resources. Thus, economically sustainable consumption is related to the consumer's decision to not buy products and the disposition to forgo specific purchases. Based on a means-end chain approach, this study investigates consumer cognitive decision-making structures related to six distinct options for economically (non-)sustainable consumption. Whereas saving motives, waste concerns, and avoidance motivations support economically sustainable decisions, economically non-sustainable decision-making is directly linked to attaining overall life goals. By clustering respondents based on the elicited means-end chains, the study discloses four consumer groups with distinctive motivational structures. The study also reveals several obstacles to promoting economic sustainability, indicates methods to overcome such obstacles, and suggests avenues for future research.