The filament forming reactions of vimentin tetramers studied in a serial-inlet microflow device by small angle x-ray scattering

The structural organization of metazoan cells and their shape are established through the coordinated interaction of a composite network consisting of three individual filament systems, collectively termed the cytoskeleton. Specifically, microtubules and actin filaments, which assemble from monomeric globular proteins, provide polar structures that serve motor proteins as tracks. In contrast, intermediate filaments (IFs) assemble from highly charged, extended coiled coils in a hierarchical assembly mechanism of lateral and longitudinal interaction steps into non-polar structures. IF proteins are expressed in a distinctly tissue-specific way and thereby serve to generate the precise plasticity of the respective cells and tissues. Accordingly, in the cell, numerous parameters such as pH and salt concentration are adjusted such that the generation of functional networks is ensured. Here, we transfer the problem for the mesenchymal IF protein vimentin to an in vitro setting and combine small angle x-ray scattering with microfluidics and finite element method simulations. Our approach is adapted to resolve the early assembly steps, which take place in the sub-second to second range. In particular, we reveal the influence of ion species and concentrations on the assembly. By tuning the flow rates and thus concentration profiles, we find a minimal critical salt concentration for the initiation of the assembly. Furthermore, our analysis of the surface sensitive Porod regime in the x-ray data reveals that the formation of first assembly intermediates, so-called unit length filaments, is not a one-step reaction but consists of distinct consecutive lateral association steps followed by radial compaction as well as smoothening of the surface of the full-width filament.     

Development as a complex process of change: Conception and analysis of projects, programs and policies

Development is often understood as a linear process of change towards Western modernity, a vision that is challenged by this paper, arguing that development efforts should rather be connected to the local stakeholders’ sense of their own development. Further, the paper contends that Complexity Theory is more effective than a linear theory of causality to analyze development and education efforts: hence, instead of studying the effects of separate development actions, the integrated factors leading to change should be considered. It is only after such analysis has been conducted, that questions of cost efficiency should be considered, using insights from the field of New Institutional Economics to avoid problems related to the stakeholders’ bounded rationality and asymmetric information leading to moral hazard.     

Extinction of conditioned inhibition: Effects of different outcome continua

For some decades, failures to find extinction of inhibition through unpaired presentations of the inhibitor were taken as evidence against conceptualizing inhibition as the symmetrical counterpart of excitation. Recently, however, our group has demonstrated successful extinction of inhibition in human causal learning. In two experiments, we replicated and strengthened this finding by using an outcome continuum that could take on negative, neutral, or positive values. In contrast, the use of a dichotomous outcome continuum (either neutral or positive) resulted in the well-known nonoccurrence of extinction. Extinction of inhibition through the pairing of inhibitors with neutral outcomes was assessed by (1) comparing the (presumably) extinguished inhibitor with a second inhibitor that had not been presented with a neutral outcome in the extinction stage, and (2) demonstrating the course of extinction in participants’ predictions.     

Understanding Starts in the Mesocosm: Conceptual metaphor as a framework for external representations in science teaching

In recent years, researchers have become aware of the experiential grounding of scientific thought. Accordingly, research has shown that metaphorical mappings between experience-based source domains and abstract target domains are omnipresent in everyday and scientific language. The theory of conceptual metaphor explains these findings based on the assumption that understanding is embodied. Embodied understanding arises from recurrent bodily and social experience with our environment. As our perception is adapted to a medium-scale dimension, our embodied conceptions originate from this mesocosmic scale. With respect to this epistemological principle, we distinguish between micro-, meso- and macrocosmic phenomena. We use these insights to analyse how external representations of phenomena in the micro- and macrocosm can foster learning when they (a) address the students’ learning demand by affording a mesocosmic experience or (b) assist reflection on embodied conceptions by representing their image schematic structure. We base our considerations on empirical evidence from teaching experiments on phenomena from the microcosm (microbial growth and signal conduction in neurons) and the macrocosm (greenhouse effect and carbon cycle). We discuss how the theory of conceptual metaphor can inform the development of external representations.     

Task Involvement and Ego Involvement: relations with academic achievement,academic self‐concept and self‐esteem

Relations between academic achievement, self‐perceptions, task involvement and defensive ego involvement (self‐presentation concerns) were explored among 349 sixth grade and 350 ninth grade Norwegian students. Task involvement was defined as general interest in working with school subjects, whereas defensive ego involvement was defined as students’ preoccupation with the impression they make on their classmates emphasizing the concern of not looking stupid. The results showed that task involvement and defensive ego involvement are independent but correlated motivational states. The concepts are negatively, but weakly correlated and are affected by different processes. Task involvement was affected directly by academic self‐concept, whereas defensive ego involvement was strongly associated with self‐esteem and was affected indirectly by academic self‐concept through self‐esteem.     

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Ohne Zusammenfassung     

Western and Chinese development discourses: Education,growth and sustainability

This article examines Western and Chinese discourses of education, sustainable growth and development. Education is increasingly considered as a means to fuel economic growth, especially since the 1980s, when conservative economic values became predominant in Western development thought. Despite a discourse on sustainability favouring ecologically sound and equitable growth, education is increasingly economy-centred. Through analysis of China’s market-based socialism, its development path, and the expansion of its Africa cooperation, this article seeks to demonstrate that the China-proposed development and education models are very similar to the Western growth-based development paradigm, although the discourse is different.