Die Juden und das Wirtschaftsleben : eine antikrit.-bibliograph. Studie zu Werner Sombart: " Die Juden und das Wirtschaftsleben"

Berlin, Univ., Diss., 1928

Beamlet based direct aperture optimization for MERT using a photon MLC

PURPOSE A beamlet based direct aperture optimization (DAO) for modulated electron radiotherapy (MERT) using photon multileaf collimator (pMLC) shaped electron fields is developed and investigated. METHODS The Swiss Monte Carlo Plan (SMCP) allows the calculation of dose distributions for pMLC shaped electron beams. SMCP is interfaced with the Eclipse TPS (Varian Medical Systems, Palo Alto, CA) which can thus be included into the inverse treatment planning process for MERT. This process starts with the import of a CT-scan into Eclipse, the contouring of the target and the organs at risk (OARs), and the choice of the initial electron beam directions. For each electron beam, the number of apertures, their energy, and initial shape are defined. Furthermore, the DAO requires dose-volume constraints for the structures contoured. In order to carry out the DAO efficiently, the initial electron beams are divided into a grid of beamlets. For each of those, the dose distribution is precalculated using a modified electron beam model, resulting in a dose list for each beamlet and energy. Then the DAO is carried out, leading to a set of optimal apertures and corresponding weights. These optimal apertures are now converted into pMLC shaped segments and the dose calculation for each segment is performed. For these dose distributions, a weight optimization process is launched in order to minimize the differences between the dose distribution using the optimal apertures and the pMLC segments. Finally, a deliverable dose distribution for the MERT plan is obtained and loaded back into Eclipse for evaluation. For an idealized water phantom geometry, a MERT treatment plan is created and compared to the plan obtained using a previously developed forward planning strategy. Further, MERT treatment plans for three clinical situations (breast, chest wall, and parotid metastasis of a squamous cell skin carcinoma) are created using the developed inverse planning strategy. The MERT plans are compared to clinical standard treatment plans using photon beams and the differences between the optimal and the deliverable dose distributions are determined. RESULTS For the idealized water phantom geometry, the inversely optimized MERT plan is able to obtain the same PTV coverage, but with an improved OAR sparing compared to the forwardly optimized plan. Regarding the right-sided breast case, the MERT plan is able to reduce the lung volume receiving more than 30% of the prescribed dose and the mean lung dose compared to the standard plan. However, the standard plan leads to a better homogeneity within the CTV. The results for the left-sided thorax wall are similar but also the dose to the heart is reduced comparing MERT to the standard treatment plan. For the parotid case, MERT leads to lower doses for almost all OARs but to a less homogeneous dose distribution for the PTV when compared to a standard plan. For all cases, the weight optimization successfully minimized the differences between the optimal and the deliverable dose distribution. CONCLUSIONS A beamlet based DAO using multiple beam angles is implemented and successfully tested for an idealized water phantom geometry and clinical situations.

Forward treatment planning for modulated electron radiotherapy (MERT) employing Monte Carlo methods

PURPOSE This paper describes the development of a forward planning process for modulated electron radiotherapy (MERT). The approach is based on a previously developed electron beam model used to calculate dose distributions of electron beams shaped by a photon multi leaf collimator (pMLC). METHODS As the electron beam model has already been implemented into the Swiss Monte Carlo Plan environment, the Eclipse treatment planning system (Varian Medical Systems, Palo Alto, CA) can be included in the planning process for MERT. In a first step, CT data are imported into Eclipse and a pMLC shaped electron beam is set up. This initial electron beam is then divided into segments, with the electron energy in each segment chosen according to the distal depth of the planning target volume (PTV) in beam direction. In order to improve the homogeneity of the dose distribution in the PTV, a feathering process (Gaussian edge feathering) is launched, which results in a number of feathered segments. For each of these segments a dose calculation is performed employing the in-house developed electron beam model along with the macro Monte Carlo dose calculation algorithm. Finally, an automated weight optimization of all segments is carried out and the total dose distribution is read back into Eclipse for display and evaluation. One academic and two clinical situations are investigated for possible benefits of MERT treatment compared to standard treatments performed in our clinics and treatment with a bolus electron conformal (BolusECT) method. RESULTS The MERT treatment plan of the academic case was superior to the standard single segment electron treatment plan in terms of organs at risk (OAR) sparing. Further, a comparison between an unfeathered and a feathered MERT plan showed better PTV coverage and homogeneity for the feathered plan, with V95% increased from 90% to 96% and V107% decreased from 8% to nearly 0%. For a clinical breast boost irradiation, the MERT plan led to a similar homogeneity in the PTV compared to the standard treatment plan while the mean body dose was lower for the MERT plan. Regarding the second clinical case, a whole breast treatment, MERT resulted in a reduction of the lung volume receiving more than 45% of the prescribed dose when compared to the standard plan. On the other hand, the MERT plan leads to a larger low-dose lung volume and a degraded dose homogeneity in the PTV. For the clinical cases evaluated in this work, treatment plans using the BolusECT technique resulted in a more homogenous PTV and CTV coverage but higher doses to the OARs than the MERT plans. CONCLUSIONS MERT treatments were successfully planned for phantom and clinical cases, applying a newly developed intuitive and efficient forward planning strategy that employs a MC based electron beam model for pMLC shaped electron beams. It is shown that MERT can lead to a dose reduction in OARs compared to other methods. The process of feathering MERT segments results in an improvement of the dose homogeneity in the PTV.

Monte Carlo based beam model using a photon MLC for modulated electron radiotherapy

PURPOSE Modulated electron radiotherapy (MERT) promises sparing of organs at risk for certain tumor sites. Any implementation of MERT treatment planning requires an accurate beam model. The aim of this work is the development of a beam model which reconstructs electron fields shaped using the Millennium photon multileaf collimator (MLC) (Varian Medical Systems, Inc., Palo Alto, CA) for a Varian linear accelerator (linac). METHODS This beam model is divided into an analytical part (two photon and two electron sources) and a Monte Carlo (MC) transport through the MLC. For dose calculation purposes the beam model has been coupled with a macro MC dose calculation algorithm. The commissioning process requires a set of measurements and precalculated MC input. The beam model has been commissioned at a source to surface distance of 70 cm for a Clinac 23EX (Varian Medical Systems, Inc., Palo Alto, CA) and a TrueBeam linac (Varian Medical Systems, Inc., Palo Alto, CA). For validation purposes, measured and calculated depth dose curves and dose profiles are compared for four different MLC shaped electron fields and all available energies. Furthermore, a measured two-dimensional dose distribution for patched segments consisting of three 18 MeV segments, three 12 MeV segments, and a 9 MeV segment is compared with corresponding dose calculations. Finally, measured and calculated two-dimensional dose distributions are compared for a circular segment encompassed with a C-shaped segment. RESULTS For 15 × 34, 5 × 5, and 2 × 2 cm(2) fields differences between water phantom measurements and calculations using the beam model coupled with the macro MC dose calculation algorithm are generally within 2% of the maximal dose value or 2 mm distance to agreement (DTA) for all electron beam energies. For a more complex MLC pattern, differences between measurements and calculations are generally within 3% of the maximal dose value or 3 mm DTA for all electron beam energies. For the two-dimensional dose comparisons, the differences between calculations and measurements are generally within 2% of the maximal dose value or 2 mm DTA. CONCLUSIONS The results of the dose comparisons suggest that the developed beam model is suitable to accurately reconstruct photon MLC shaped electron beams for a Clinac 23EX and a TrueBeam linac. Hence, in future work the beam model will be utilized to investigate the possibilities of MERT using the photon MLC to shape electron beams.

Jüdische Realpolitik in Oesterreich : ein Vademecum für ernst Denkende

von M. Rosenmann

Die Unfähigkeit zu schreiben: Eine Verarbeitungsgeschichte des Nationalsozialismus anhand der Briefe von Maria Gleit an Ernst Kreuder

Mit dem 8. Mai 1945 ist das Exil der aus dem nationalsozialistischen Deutschland und Österreich Geflohenen und Vertriebenen nicht beendet. Aber Versuche, Kontakt aufzunehmen und an alte Beziehungen anzuknüpfen, setzen ein, um Lebensumstände, Positionen, Stimmungen und aktuelle Entwicklungen zu klären. In den Beiträgen des Sammelbandes geht es um Briefe von Frauen unterschiedlicher sozialer Herkunft und Lage, politischer Überzeugung und beruflicher Ausbildung und Perspektive: Ella Bergmann- Michel, Ilse Bing, Erna Blencke, Erna Döblin, Maria Gleit, Gabriele Kätzler, Hildegard Kramer, Vera Lachmann, Luise von Leyden, Johanna Marum, Lili Pollatz, Anna Siemsen, Minna Specht, Hilde Spiel, Grete Weil und Alma S. Wittlin schreiben über traumatische Erfahrungen, über die NS-Verbrechen, die Entfremdung und auch über ihre Akkulturation im Exilland sowie über ihre Pläne und die Vorbereitung einer möglichen Rückkehr, sofern diese nicht kategorisch abgelehnt wird, und über ihre Hoffnungen und Enttäuschungen nach der Remigration.

Rainer Werner Fassbinder’s "Garbage, The City, and Death". A Four Act Scandal in Post-war Germany

Rainer Werner Fassbinder’s Garbage, The City, and Death. A Four Act Scandal in Post-war Germany The paper explores the dramaturgy of the scandals around the play Garbage, The City and Death (Der Müll, die Stadt und der Tod) by German playwright, theatre and film maker Rainer Werner Fassbinder. Published in 1976, the play immediately caused a scandal in West Germany, because it was accused of reproducing anti-Semitic stereotypes. The presentation sheds light on the different phases of the scandal and their historical and cultural contexts in post-war Germany – starting as a literary scandal in 1976, being transformed into a theatre scandal in the 1980ies and finally being dissolved by the German premiere in 2009. The paper is structured as follows: Act One: The Literary Scandal. Destroying Fassbinder’s Garbage, Act Two: Preventing the Staging of the Play, Act Three: Blocking the Opening Night, Act Four: Performing the Play in Germany. By analysing the dramaturgical structure of this specific scandal, the paper discusses the following hypotheses: 1. Scandals arise through the circulation of decontextualised information in public. This is due to either a lack of information about the actual object or incident being scandalised or a lack of information about the context of the object or incident. This lack is caused by the logic of the scandal itself: Because the play or the performance is prohibited, it has been withdrawn from the public, making it impossible to form a well-founded opinion on the controversy. 2. The scandal is driven forward by an emotionalising rhetoric built around the decontextualised information. 3. Once the gap of information is filled, the scandalising rhetoric turns into a rhetoric of irrelevance: Reviews of the first performance of Garbage, The City and Death in Germany considered the play hardly a matter of public concern.

Ms.Ff.F.Stoltze 3. 273 - Brief von Ernst Schalck an Friedrich Stoltze

Umzug, Frankfurter Latern

Ms.Ff.F.Stoltze 3. 276 - Brief von Ernst Schalck an Friedrich Stoltze

Frankfurter Latern, Hampelmann

Intransitive competition is widespread in plant communities and maintains their species richness

Intransitive competition networks, those in which there is no single best competitor, may ensure species coexistence. However, their frequency and importance in maintaining diversity in real-world ecosystems remain unclear. We used two large data sets from drylands and agricultural grasslands to assess: (1) the generality of intransitive competition, (2) intransitivity–richness relationships and (3) effects of two major drivers of biodiversity loss (aridity and land-use intensification) on intransitivity and species richness. Intransitive competition occurred in > 65% of sites and was associated with higher species richness. Intransitivity increased with aridity, partly buffering its negative effects on diversity, but was decreased by intensive land use, enhancing its negative effects on diversity. These contrasting responses likely arise because intransitivity is promoted by temporal heterogeneity, which is enhanced by aridity but may decline with land-use intensity. We show that intransitivity is widespread in nature and increases diversity, but it can be lost with environmental homogenisation.

Funfzehn neue deutsche Lieder zu alten Singweisen : den deutschen Männern Ernst Moritz Arndt und Ludwig Uhland gewidmet

Welsch (Projektbearbeiter): Abdruck von fünfzehn Gedichten mit patriotischem Inhalt