Computing The Modulation Transfer Function Of Magnetic Resonance Imagers

The quality of images produced by imaging devices of all types can be analyzed and quantified by a variety of metrics. Resolution is an important metric for all imaging devices because if the resolution characteristics do not meet the minimum requirements of an application, the resultant image may be unsuitable and possibly misleading. One resolution metric, called the Modulation Transfer Function (MTF), describes the ratio of input to output signal magnitude as a function of spatial frequency. Application of the MTF is limited to systems whose output scales linearly with input (linearity) and produces the same output image regardless of object position (shift invariance).;Although a variety of experimental MTF analysis techniques have been developed for a range of imaging devices, no suitable technique has been developed for a linear, shift invariant (within sub-regions) medical imaging modality called Magnetic Resonance Imaging (MRI). Magnetic Resonance Imaging is the three dimensional imaging modality of choice for detecting various soft tissue pathologies in the head, spinal cord and other anatomical regions of the human body. Unfortunately, most MR images are produced by the magnitude Fourier Transform (FT) reconstruction algorithm, a non-linear method which is not amenable to previously developed MTF analysis techniques. A new MTF analysis method, presented here, and developed specifically for MRI, eliminates the errors caused by the magnitude operator in the reconstruction algorithm by using the complex image formed just prior to the magnitude operator and modifying the MTF theory accordingly. Tests with experimentally produced MRI data have confirmed the feasibility of the new technique by producing accurate MTF\u27s which agree with theoretically predicted resolution characteristics

Marxistische Parteiendebatte revisited: Zur Verortung politischer Parteien in der Bürgerlichen Gesellschaft

Different from approaches to political parties with an affirmative stance towards capitalist domination, Marxist social theory claims to assess the role of parties within Bourgeois society from a critical perspective. Nevertheless, existing debates on political parties in capitalism suffer from a narrow focus on forms and functions. They tend to become functionalist and reductionist on class struggles instead of analyzing different relations of domination. Due to this shortcoming, it is necessary to develop a materialist understanding which takes into account some helpful insights from Gramsci’s concept of political and societal party. His understanding of domination as hegemony provides us with rich analytical instruments: Now we can grasp more precisely to what extent parties play a crucial role in organizing consent within society and how they manage to do so. By critically assessing the Marxist debate on political parties and enriching it with a stronger focus on hegemony, I want to offer a more comprehensive conceptual framework which might be useful for empirical studies

Neoliberal-Islamische Synthese in der Türkei: Der Herrschaftsmodus der AKP

After several landslide victories in the elections since 2002, Islamic Justice and Development Party (AKP) has been forming an unchallenged single party government in Turkey. There is a broad and controversial debate on the success and prospects of its societal project. Along with the rise of the ‘Arab Spring’ AKP is even being discussed as a role model party for a moderate Islam in a ‘Muslim democracy’. Far from agreeing with such assessments and based on a Gramscian theoretical approach, this article critically sheds light on the current political and social developments in Turkey on four exemplary fields: democratization process, economic adjustments, faith-based charity and education. As distinct from most Turkey-related research in Germany, which often sees AKP’s power politics as the outcome of a cultural clash of antagonistic elites, this article examines the intertwined dynamics of gaining consent and exercising coercion in the process of capitalist domination. It stresses the contradictory nature of AKP’s cross-culture- and crossclass- coalition, in order to provide a more complex understanding of how AKP’s rule is still met with (comparatively broad) approval of different dominated groups and classes – despite the enormous repression of critical voices

Semillas en el tiempo : el latinoamericanismo filosófico contemporáneo

Los trabajos que conforman este Iibro giran en torno a un eje: los filósofos latinoamericanistas contemporáneos, desde 1950 en adelante. Todos ellos pensadores que han reflexionado desde adentro, desde el continente acerca de la identidad cultural y social de América Latina: ¿qué es América, qué es ser americano, cuál es su historia, cuáles son sus contribuciones, qué problemas se derivan de sus relaciones con el Occidente, qué problemas del pasado inciden en su presente, de qué modo debe asumir ese pasado, qué conflictos se desprenden de su estructura de clases? Éstas son algunas de las preguntas que vertebran el nuevo movimiento, que se cuestiona fuertemente la identidad latinoamericana. La relevancia especial de "Semillas en el tiempo" reside en que los autores de los estudios son destacados especialistas en la materia, tanto por sus conocimientos acerca de la Filosofía, como por su dedicación al estudio de la problemática latinoamericana

Laparoscopic sleeve gastrectomy in heart failure patients with left ventricular assist device

Background: There is limited data in the literature evaluating outcomes of bariatric surgery in severely obese patients with left ventricular assist device (LVAD) as a bridge to make them acceptable candidates for heart transplantation. This study aims to assess the safety and effectiveness of laparoscopic sleeve gastrectomy (LSG) in patients with previously implanted LVAD at our institution. Methods: All the patients with end-stage heart failure (ESHF) and implanted LVAD who underwent LSG from2013 to January 2017 were studied. Results: Seven patients with end stage heart failure (ESHF) and implanted LVAD were included. The median age and median preoperative BMI were 39 years (range: 26–62) and 43.6 kg/m2 (range 36.7–56.7), respectively. The median interval between LVAD implantation and LSG was 38 months (range 15–48). The median length of hospital stay was 9 days (rang: 6–23) out of which 4 patients had planned postoperative ICU admission. Thirty-day complications were noted in 5 patients (3 major and 2 minor) without any perioperative mortality. The median duration of follow-up was 24 months (range 2–30). At the last available follow-up, the median BMI, %EWL, and %TWL were 37 kg/m2 , 47%, and 16%, respectively. The median LVEF before LSG and at the last follow-up point (before heart transplant) was 19% (range 15–20) and 22% (range, 16–35), respectively. In addition, the median NYHA class improved from 3 to 2 after LSG. Three patients underwent successful heart transplantations. Conclusion: Patients with morbid obesity, ESHF, and implanted LVAD constitute a high-risk cohort. Our results with 7 patients and result from other studies (19 patients) suggested that bariatric surgery may be a reasonable option for LVAD patients with severe obesity. Bariatric surgery appears to provide significant weight loss in these patients and may improve candidacy for heart transplantation

Römische Götterbilder der mittleren und späten Kaiserzeit

Die Götterbilder der fortgeschrittenen römischen Kaiserzeit folgen einer traditionellen Bildsprache, die durch die vorbildhaften Statuen der griechischen Klassik geprägt ist. Gleichzeitig unterscheiden sie sich signifikant von früheren Epochen: Vorbilder werden variiert, Elemente verschiedener Bildwerke miteinander kombiniert und eigene Bild- und Erzählzusammenhänge neu geschaffen. Die Götterstatuen des 2. bis 4. Jahrhunderts n. Chr. erhalten immer mehr Attribute und dekorative Details; Statuenstützen und Plinthen werden mit beigeordneten Figuren bereichert; statuarische Gruppen setzen Handlungsabläufe in Szene. Die Beiträge dieses Bandes untersuchen, wie Götterbilder der mittleren und der späteren Kaiserzeit gewandelte religiöse Vorstellungen visualisieren und ihnen eine sinnlich erfahrbare Präsenz verleihen. Sie zeigen, wie sich damit ältere Auffassungen vom Wesen der Götter stabilisieren, gleichzeitig aber auch neue religiöse Auffassungen manifest und verstetigt werden

Klostergut und Villa rustica. Ergebnisse der Thermengrabung Samos-Stadt

Steckner Cornelius. Klostergut und Villa rustica. Ergebnisse der Thermengrabung Samos-Stadt. In: Actes du XIe congrès international d'archéologie chrétienne. Lyon, Vienne, Grenoble, Genève, Aoste, 21-28 septembre 1986. Rome : École Française de Rome, 1989. pp. 2727-2738. (Publications de l'École française de Rome, 123

Symbol formation

Symbol formation is a term used to unify the view on the interdependencies in the research of the Hamburg University before 1933: the Philosophical Institute (William Stern, Ernst Cassirer), the Psychological Institute (Stern) with its laboratory (Heinz Werner) in cooperation with the later joining Umwelt Institut (Jakob von Uexküll). The term, definitely used by Cassirer and Werner, is associated with the personalistic approach: “Keine Gestalt ohne Gestalter” (Stern), but also covers related terms like “melody of motion” (Uexküll), and “relational content” (Cassirer), discussing the term “empirical scheme” (Kant). All this scientific interest addressed personal forces to structure thresholds in equivalent stimuli. This view on intermodal formation allowed research in common aspects in the environments of animals, of children and adults to meet there the symbol formation of artists (Weimar Bauhaus) and poets like R. M. Rilke, a friend of Uexküll

Klostergut und Villa rustica. Ergebnisse der Thermengrabung Samos-Stadt

Steckner Cornelius. Klostergut und Villa rustica. Ergebnisse der Thermengrabung Samos-Stadt. In: Actes du XIe congrès international d'archéologie chrétienne. Lyon, Vienne, Grenoble, Genève, Aoste, 21-28 septembre 1986. Rome : École Française de Rome, 1989. pp. 2727-2738. (Publications de l'École française de Rome, 123