Alles im weißen Bereich?: Institutioneller Rassismus in Sachsen: Erweiterter Tagungsband

Die Tagung «Alles im weißen Bereich. Institutioneller Rassismus in Sachsen», die im Februar 2014 stattfand, war die fünfte Tagung in unserer Reihe zu Fragen der Demokratie. Der Gegenstand von Tagung und Sammelband steht für uns einerseits in logischer Reihenfolge bisheriger Fragen und Diskussionen zu den Zuständen Sächsischer Demokratie. Insbesondere war unsere Entscheidung in der Vorbereitung aber auch von der Arbeit der Untersuchungs-ausschüsse zum «NSU» angeregt worden. Ohne den Rassismus, der als grundlegender gesellschaftlicher Wissensbestand existiert, ist die Geschichte und das Versagen des staatlichen Sicherheitsapparates im Zusammenhang mit dem NSU schwer vorstellbar oder nicht möglich. Rassismus ist damit nicht nur das Motiv für die Ermordung von Menschen, sondern auch ein entscheidender Grund dafür, dass diese Morde nicht wirksam verhindert und teilweise nicht oder erst sehr spät aufgeklärt werden können. Diese Feststellung scheint offensichtlich, sie hat sich aber trotz einer breit geführten öffentlichen Debatte und der Arbeit verschiedener Untersuchungsausschüsse als nicht mehrheitsfähig erwiesen. Ebenso wenig konnte Institutioneller Rassismus als Perspektive und Analyseinstrument politisch etabliert werden. Redaktionsschluss: November 201

Systematic variations in microvilli banding patterns along fiddler crab rhabdoms

Polarisation sensitivity is based on the regular alignment of dichroic photopigment molecules within photoreceptor cells. In crustaceans, this is achieved by regularly stacking photopigment-rich microvilli in alternating orthogonal bands within fused rhabdoms. Despite being critical for the efficient detection of polarised light, very little research has focused on the detailed arrangement of these microvilli bands. We report here a number of hitherto undescribed, but functionally relevant changes in the organisation of microvilli banding patterns, both within receptors, and across the compound eye of fiddler crabs. In all ommatidia, microvilli bands increase in length from the distal to the proximal ends of the rhabdom. In equatorial rhabdoms, horizontal bands increase gradually from 3 rows of microvilli distally to 20 rows proximally. In contrast, vertical equatorial microvilli bands contain 15-20 rows of microvilli in the distal 30 μm of the rhabdom, shortening to 10 rows over the next 30 μm and then increase in length to 20 rows in parallel with horizontal bands. In the dorsal eye, horizontal microvilli occupy only half the cross-sectional area as vertical microvilli bands. Modelling absorption along the length of fiddler crab rhabdoms suggests that (1) increasing band length assures that photon absorption probability per band remains constant along the length of photoreceptors, indicating that individual bands may act as units of transduction or adaptation; (2) the different organisation of microvilli bands in equatorial and dorsal rhabdoms tune receptors to the degree and the information content of polarised light in the environment

Enhancing stocks of the exploited limpet Patella candei d’Orbigny via modifications in coastal engineering

It is widely recognised that microhabitats are important for a variety of marine organisms, yet this knowledge has rarely been applied in the construction of engineered structures as a means of enhancing biodiversity or populations of species at risk. Here we examined the influence of microhabitats on the distribution and survival of the exploited limpet Patella candei on natural shores before determining the effect of introducing such habitats to an artificial seawall. On natural shores individuals were associated with pits (a natural feature of volcanic rocky shores). Animals inhabiting pits showed reduced mortality and were smaller than those on open rock. Microhabitat utilisation was similar over the vertical range of distribution of P. candei. Following observation of natural patterns, we applied this knowledge by experimentally drilling pits at varying densities and sizes in a seawall that had been constructed with simple topographical complexity. Overall, the number of animals increased in areas with experimentally increased microhabitat area. There was evidence that this was the result of immigration (larger animals) but also of increased recruitment. This study demonstrates one cost-effective way of conciliating the need to protect our coastlines while promoting the conservation and stock enhancement of over-exploited species