Investigating the role that the Southern Ocean biological pump plays in determining global ocean oxygen concentrations and deoxygenation

Global ocean circulation connects marine biogeochemical cycles through the long-range transport of nutrients and oxygen with the Southern Ocean (SO) acting as a water mass crossroads. The biological pump in the SO has been shown to play an important role in these dynamics and the amount of export production is known to have a large impact on remote deep ocean nutrients and dissolved inorganic carbon. However, the role that the SO biological pump plays in determining ocean oxygen concentrations is less well understood. In this study we investigate these dynamics by shutting off the SO biological pump in three different general ocean circulation models, each of which is coupled to a different prognostic biogeochemical model. Our results indicate that the present day SO biological pump is responsible for reducing oxygen levels in the deep ocean by up 70 mmol m-3. The SO biological pump also removes nutrients that would otherwise be used to fuel productivity and subsequently reduce oxygen in mid- to low-latitude sub-surface waters (i.e., without the SO biological pump, oxygen is lower in these regions due to higher productivity). Since SO productivity and export is expected to change in response to climate change we also examine the role that these changes may play in future ocean deoxygenation

Gleichermaßen hochwertig und einheitlich lang: Gewerkschaftliche Anforderungen an die Reform der Lehrerbildung im Bologna-Prozess

Zunächst setzt sich der Autor mit dem Verlauf des Bologna-Prozesses aus gewerkschaftlicher Sicht kritisch auseinander. Dann stellt der Autor 1) „Anfängliche Übereinstimmungen“, 2) „Misslungene Umsetzung“ und 3) „Kritikpunkte“ an dem Verlauf des Bologna-Prozesses heraus. (DIPF/ ssch

Der Dschihadismus als transnationale soziale Bewegung

Seitdem in Folge der Anschläge des 11. Septembers 2011 das Phänomen des Dschihadismus in den Fokus der medialen und wissenschaftlichen Aufmerksamkeit gerückt ist, versuchen verschiedene Ansätze, Erklärungen zu finden. Diese Arbeit zeigt, dass der Dschihadismus als transnationale soziale Bewegung gesehen werden kann, die auf Identität abzielt. Der Dschihadismus versucht, eine schon vorhandene kollektive Identität umzudeuten; er bietet alternative Interpretationen für Ereignisse und seine Anhänger teilen gemeinsame Narrative, Symbole, Mythen, Helden und Praktiken. Durch die Anwendung von Bewegungsparadigmen ermöglicht die Arbeit die Analyse emischer Perspektiven des Dschihadismu

A structural analysis of the A5/1 state transition graph

We describe efficient algorithms to analyze the cycle structure of the graph induced by the state transition function of the A5/1 stream cipher used in GSM mobile phones and report on the results of the implementation. The analysis is performed in five steps utilizing HPC clusters, GPGPU and external memory computation. A great reduction of this huge state transition graph of 2^64 nodes is achieved by focusing on special nodes in the first step and removing leaf nodes that can be detected with limited effort in the second step. This step does not break the overall structure of the graph and keeps at least one node on every cycle. In the third step the nodes of the reduced graph are connected by weighted edges. Since the number of nodes is still huge an efficient bitslice approach is presented that is implemented with NVIDIA's CUDA framework and executed on several GPUs concurrently. An external memory algorithm based on the STXXL library and its parallel pipelining feature further reduces the graph in the fourth step. The result is a graph containing only cycles that can be further analyzed in internal memory to count the number and size of the cycles. This full analysis which previously would take months can now be completed within a few days and allows to present structural results for the full graph for the first time. The structure of the A5/1 graph deviates notably from the theoretical results for random mappings.Comment: In Proceedings GRAPHITE 2012, arXiv:1210.611

Attention and Olfactory Consciousness

Understanding the relation between attention and consciousness is an important part of our understanding of consciousness. Attention, unlike consciousness, can be systematically manipulated in psychophysical experiments and a law-like relation between attention and consciousness is waiting to be discovered. Most attempts to discover the nature of this relation are focused on a special type of attention: spatial visual attention. In this review I want to introduce another type of attention to the discussion: attention to the olfactory modality. I will first clarify the position of attention to smells in a general taxonomy of attention. I will then review the mechanisms and neuroanatomy of attention and consciousness in the olfactory system before using the newly introduced system to provide evidence that attention is necessary for consciousness