Model prediction of subendocardial perfusion of the coronary circulation in the presence of an epicardial coronary artery stenosis

The subendocardium is most vulnerable to ischemia, which is ameliorated by relaxation during diastole and increased coronary pressure. Recent clinical techniques permit the measuring of subendocardial perfusion and it is therefore important to gain insight into how measurements depend on perfusion conditions of the heart. Using data from microsphere experiments a layered model of the myocardial wall was developed. Myocardial perfusion distribution during hyperemia was predicted for different degrees of coronary stenosis and at different levels of Diastolic Time Fraction (DTF). At the reference DTF, perfusion was rather evenly distributed over the layers and the effect of the stenosis was homogenous. However, at shorter or longer DTF, the subendocardium was the first or last to suffer from shortage of perfusion. It is therefore concluded that the possible occurrence of subendocardial ischemia at exercise is underestimated when heart rate is increased and DTF is lower

The German science of geopolitics in the Netherlands, 1920-1945

In the 1920s, Karl Haushofer founded Geopolitik in München as a form of applied political geography. German geopoliticians perceived territorial loss of their country after 1918 through the social darwinist lens. They considered states as types of organisms that rivalled over territories (Lebensraum). ‘Natural’ selection determined the outcome. Geopolitics was aligned with the nazis despite theoretical differences (space vs. race). The reception of German geopolitics among geographers in Dutch universities (especially in the geography departments of Utrecht and Amsterdam) during the Interbellum and the German occupation varied. Keen interest in the highly reputed sister-universities across the border did not result in uniform reactions to the academic implications of the nazi rise to power, as was also evident in other ideologically sensitive fields such as archeology and eugenetics. This article analyses the cooperation of S.R. Steinmetz and L. Van Vuuren, the main chair holders in Dutch human geography, in German geopolitical publications and the reactions of their successors. While H.N. ter Veen, Steinmetz’ eventual successor, strongly rejected the geopolitical project, J.G. Loohuis, Van Vuuren’s erstwhile student, reacted approvingly. He was the only academic geopolitician to work at a Dutch university, nominated during the war at the strong request of the occupation authorities

How German geopolitics passed through the Netherlands, 1920 - 1945: a case study in the geography of one of geography's 'projects’

German geopolitics emerged from the early 1920s. It was noticed in the Netherlands but not broadly embraced. In public discourse the term ‘geopolitics’ was hardly ever used between the First and Second World Wars but it became a bit more common with the looming threat of a second war and during the German occupation. Meanwhile Dutch geographers took note of the efforts of Haushofer and his circle. Around 1930, their initial reaction to this project took various forms - constructive criticism, co-operation and indignant dismissal - but the attention waned over the decade. During the occupation Nazi-friendly geographers discussed the launching of a new geopolitics. The generally shared Dutch preference for aloofness, neutrality and recourse to international law as the way to approach international relations precluded the formation of a large, responsive public for German geopolitics. The high status of German academia provided an initial audience of Dutch academic geographers