3,501 research outputs found
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
Does Military Draft Discourage Enrollment in Higher Education? Evidence from OECD Countries
Using data from 1960-2000 for OECD countries, we analyze the impact of compulsory military service on the demand for higher education, measured by students enrolled in tertiary education as a share of the working-age population. Based on a theoretical model, we hypothesize that military draft has a negative effect on education. Empirically, we confirm this for the existence of conscription, albeit usually at low statistical significance. However, the intensity of its enforcement, measured by the share of the labor force conscripted by the military and the duration of service, significantly reduces enrollment in higher education.conscription, human capital
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
Does Military Draft Discourage Enrollment in Higher Education? Evidence from OECD Countries
Using data from 1960-2000 for OECD countries, we analyze the impact of compulsory military service on the demand for higher education, measured by students enrolled in tertiary education as a share of the working-age population. Based on a theoretical model, we hypothesize that military draft has a negative effect on education. Empirically, we confirm this for the existence of conscription, albeit usually at low statistical significance. However, the intensity of its enforcement, measured by the share of the labor force conscripted by the military and the duration of service, significantly reduces enrollment in higher education.human capital, conscription
Olfaction As The Paradigm For Perceptual Philosophy
Plato wrote that smell is of a half-formed nature and that not much can be said about it, and Kant identified smell as the most ungrateful and most dispensable of the senses. Because contemporary philosophers share this distaste for smell perception, olfaction is often dismissed or ignored in philosophical accounts of perception. Instead, contemporary philosophy of perception is based almost exclusively on visual perception. The goal of this dissertation is to show that this focus on a single modality distorts our understanding of what perception is.
I am not the first to realize the potential of opening up perceptual philosophy to the non-visual modalities. Bill Lycan asked how the philosophy of perception would be different if smell had been taken as a paradigm rather than vision. (Lycan 2000). In this dissertation, I will try to answer this question. My analysis will show that philosophy of perception would be very different, were it based on olfaction. Many of the most basic concepts of philosophy of perception are based on peculiarities of visual perception that do not generalize to other modalities
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
The evolutionary function of conscious information processing is revealed by its task-dependency in the olfactory system
Although many responses to odorous stimuli are mediated without olfactory information being consciously processed, some olfactory behaviors require conscious information processing. I will here contrast situations in which olfactory information is processed consciously to situations in which it is processed non-consciously. This contrastive analysis reveals that conscious information processing is required when an organism is faced with tasks in which there are many behavioral options available. I therefore propose that it is the evolutionary function of conscious information processing to guide behaviors in situations in which the organism has to choose between many possible responses
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