119 research outputs found
Faschismus in der DDR: Zur AktualitÀt von Brecbts Lylik der Politik
Leipzig, 11. Dezember 1989. Wie jeden Montag seit dem denkwĂŒrdigen 9. Oktober, der ĂŒber eine chinesische oder eine demokratische Lösung in der DDR entschieden hat, versammeln sich wieder ca. 100,000 Demonstranten in der Leipziger Innenstadt. Es ist nicht mehr jener friedliche Volksaufstand, der die Revolution in der DDR schon jetzt zum Mythos werden lieĂ. nzwischen demonstrieren zwei Gruppen, nicht inehr friedlich
miteinander, sondern feindlich gegeneinander. Aggressiv und mit Gewalt drohend schlĂ€gt die eine Gruppe der Demonstranten - noch verbal - auf die andere ein. Tausendfach tönt der Ruf: ăir sind Deutsche, was seid ihr?ă, ăaules Pack, faules Pack!«. Sie tragen Transparente mit der Aufschrift ăeutschland, einig Vaterland«, und beantworten Fragen und EinwĂ€nde mităGeht doch nach RuĂland!« In GesprĂ€chen mit den Gegendemonstranten wird geĂ€uĂert: die Republikaner seien, so habe man bei Besuchen im Westen festgestellt, keine Menschenfresser mit Messern zwischen den Lippen
Tests und Inbetriebnahme der LHCb Outer Tracker Front-end Elektronik und eine Studie zur AbschÀtzung des Untergrundes im Zerfall B s 0 - J/Psi Phi
Die Ausleseelektronik des Outer Tracker des LHCb-Detektors vermisst die Driftzeiten in Straw-ProportionalzĂ€hlern. Die Front-end Elektronik des Outer Tracker besteht dabei aus drei strahlenharten Chips. Der ASDBLR VorverstĂ€rker verstĂ€rkt und diskriminiert den Ladungspuls der Driftkammern. Der OTIS-TDC Chip vermisst das dikriminierte Signal alle 25 ns auf 32 DetektorkanĂ€len. Die gemessenen Driftzeiten werden mittels den GOL-Serialisierer ĂŒber einen optischen Link mit 1,6 GBit/s versendet. Der Hauptanteil dieser Arbeit beschĂ€ftigt sich mit dem Testen und der Inbetriebnahme dieser Outer Tracker Front-end Elektronik. Dazu wurden insgesamt drei Testsystem entwickelt und betrieben. Mit einem ersten System wurden die OTIS-TDC Chips noch auf dem Wafer intensiv auf ihre Eigenschaften hin ĂŒberprĂŒft. In weiteren Testaufbauten wurde anschlieĂend die QualitĂ€t der OTIS-Karten und der GOL-Aux Karten Produktion ĂŒberwacht. Weiterhin wurde die Front-end Elektronik in die Auslesekette des LHCb-Detektors integriert und getestet. Ein wichtiges Ziel des LHCb-Experimentes besteht in der Bestimmung der CP-Verletzenden Phase Phi_s. Diese kann ĂŒber den "goldenen"' Zerfall Bs -> J/Psi Phi bestimmt werden. FĂŒr die Extraktion dieser GröĂe ist die Kenntnis ĂŒber den Untergrund von essentieller Bedeutung. In dieser Arbeit wurde eine Studie durchgefĂŒhrt, welche die bisherigen BeschrĂ€nkungen durch die Statistik der Monte-Carlo Simulationen in der Bestimmung diese Untergrundes aufhebt
Controlling a Vlasov-Poisson plasma by a Particle-In-Cell method based on a Monte Carlo framework
The Vlasov-Poisson system describes the time evolution of a plasma in the
so-called collisionless regime. The investigation of a high-temperature plasma
that is influenced by an exterior magnetic field is one of the most significant
aspects of thermonuclear fusion research. In this paper, we formulate and
analyze a kinetic optimal control problem for the Vlasov-Poisson system where
the control is represented by an external magnetic field. The main goal of such
optimal control problems is to confine the plasma in a certain region in phase
space. We first investigate the optimal control problem in terms of
mathematical analysis, i.e., we show the existence of at least one global
minimizer and we rigorously derive a first-order necessary optimality condition
for local minimizers by the adjoint approach. Then, we build a Monte Carlo
framework to solve the state equations as well as the adjoint equations by
means of a Particle-In-Cell method, and we apply a nonlinear conjugate gradient
method to solve the optimization problem. Eventually, we present numerical
experiments that successfully validate our optimization framework
From Targets to Action : Rolling up our Sleeves after Paris
At the United Nations Climate Change Conference in Paris in 2015 ambitious targets for responding to the threat of climate change have been set: limiting global temperature increase to âwell below 2 °C [âŠ] and to pursue efforts to limit the temperature increase to 1.5 °Câ. However, calculating the CO2 budget for 1.5 °C, it becomes clear that there is nearly no room left for future emissions. Scenarios suggest that negative emission technologies will play an even more important role for 1.5 °C than they already play for 2 °C. Especially against this background the feasibility of the target(s) is hotly debated, but this debate does not initiate the next steps that are urgently needed. Already the negotiations have featured the move from targets to implementation which is needed in the coming decade. Most importantly, there is an urgent need to develop and implement instruments that incentivize the rapid decarbonization. Moreover, it needs to be worked out how to link the climate and development agenda and prevent a buildup of coal power causing lock-in effects. Short term entry points into climate policy should now be in the focus instead of the fruitless debate on the feasibility of targets
Wafer test of the LHCb Outer Tracker TDC-Chip
The OTIS-TDC is the front end readout chip for the LHCb Outer Tracker. It is designed to measure drift times with a resolution better than 1 ns. As the chip will be directly mounted to its board, the test have to be performed on the wafer itself. As the testing period for 7 000 chips was only three weeks, many test routines have been implemented on a FPGA. Each chip is subjected to detailed probe testing to ensure the full functionality as well as a good performance. Overall 47 wafer have been tested. From the chips passing the test 2 000 have been used in the Outer Tracker front end electronic
How the Emitted Size Distribution and Mixing State of Feldspar Affect Ice Nucleating Particles in a Global Model
The effect of aerosol particles on ice nucleation and, in turn, the formation of ice and mixed phase clouds is recognized as one of the largest sources of uncertainty in climate prediction. We apply an improved dust mineral specific aerosol module in the NASA GISS Earth System ModelE, which takes into account soil aggregates and their fragmentation at emission as well as the emission of large particles. We calculate ice nucleating particle concentrations from K-feldspar abundance for an active site parameterization for a range of activation temperatures and external and internal mixing assumption. We find that the globally averaged INP concentration is reduced by a factor of two to three, compared to a simple assumption on the size distribution of emitted dust minerals. The decrease can amount to a factor of five in some geographical regions. The results vary little between external and internal mixing and different activation temperatures, except for the coldest temperatures. In the sectional size distribution, the size range 24 micrometer contributes the largest INP number
How the Assumed Size Distribution of Dust Minerals Affects the Predicted Ice Forming Nuclei
The formation of ice in clouds depends on the availability of ice forming nuclei (IFN). Dust aerosol particles are considered the most important source of IFN at a global scale. Recent laboratory studies have demonstrated that the mineral feldspar provides the most efficient dust IFN for immersion freezing and together with kaolinite for deposition ice nucleation, and that the phyllosilicates illite and montmorillonite (a member of the smectite group) are of secondary importance.A few studies have applied global models that simulate mineral specific dust to predict the number and geographical distribution of IFN. These studies have been based on the simple assumption that the mineral composition of soil as provided in data sets from the literature translates directly into the mineral composition of the dust aerosols. However, these tables are based on measurements of wet-sieved soil where dust aggregates are destroyed to a large degree. In consequence, the size distribution of dust is shifted to smaller sizes, and phyllosilicates like illite, kaolinite, and smectite are only found in the size range 2 m. In contrast, in measurements of the mineral composition of dust aerosols, the largest mass fraction of these phyllosilicates is found in the size range 2 m as part of dust aggregates. Conversely, the mass fraction of feldspar is smaller in this size range, varying with the geographical location. This may have a significant effect on the predicted IFN number and its geographical distribution.An improved mineral specific dust aerosol module has been recently implemented in the NASA GISS Earth System ModelE2. The dust module takes into consideration the disaggregated state of wet-sieved soil, on which the tables of soil mineral fractions are based. To simulate the atmospheric cycle of the minerals, the mass size distribution of each mineral in aggregates that are emitted from undispersed parent soil is reconstructed. In the current study, we test the null-hypothesis that simulating the presence of a large mass fraction of phyllosilicates in dust aerosols in the size range 2 m, in comparison to a simple model assumption where this is neglected, does not yield a significant effect on the magnitude and geographical distribution of the predicted IFN number. Results from sensitivity experiments are presented as well
CNS demyelinating events in primary Sjogren's syndrome: A single-center case series on the clinical phenotype
ObjectiveThe study aimed to assess the prevalence, clinical characteristics, and therapeutic outcomes of the central nervous system (CNS) demyelinating disease in a large cohort of primary Sjogren's syndrome (pSS). MethodsThis is an explorative cross-sectional study of patients with pSS seen in the departments of rheumatology, otorhinolaryngology, or neurology of a tertiary university center between January 2015 and September 2021. ResultsIn a cohort of 194 pSS patients, 22 patients had a CNS manifestation. In this CNS group, 19 patients had a lesion pattern suggestive of demyelination. While there were no obvious differences in the patients' epidemiological disposition or rate of other extraglandular manifestations, the CNS group differed from the remaining patients with pSS by having less glandular manifestations but a higher seroprevalence for anti-SSA/Ro antibodies. Notably, patients with CNS manifestations were often diagnosed with multiple sclerosis (MS) and treated as such, although age and disease course were atypical of MS. Many first-line MS agents were ineffective in these MS look-alikes;however, the disease course was benign with B-cell-depleting agents. ConclusionNeurological symptoms of pSS are common and clinically manifest mainly as myelitis or optic neuritis. Notably, in the CNS, the pSS phenotype can overlap with MS. The prevailing disease is crucial since it has a major impact on the long-term clinical outcome and the choice of disease-modifying agents. Although our observations neither confirm pSS as a more appropriate diagnosis nor rule out simple comorbidity, physicians should consider pSS in the extended diagnostic workup of CNS autoimmune diseases
An approach for estimating dosimetric uncertainties in deformable dose accumulation in pencil beam scanning proton therapy for lung cancer
Deformable image registration (DIR) is an important component for dose accumulation and associated clinical outcome evaluation in radiotherapy. However, the resulting deformation vector field (DVF) is subject to unavoidable discrepancies when different algorithms are applied, leading to dosimetric uncertainties of the accumulated dose. We propose here an approach for proton therapy to estimate dosimetric uncertainties as a consequence of modeled or estimated DVF uncertainties. A patient-specific DVF uncertainty model was built on the first treatment fraction, by correlating the magnitude differences of five DIR results at each voxel to the magnitude of any single reference DIR. In the following fractions, only the reference DIR needs to be applied, and DVF geometric uncertainties were estimated by this model. The associated dosimetric uncertainties were then derived by considering the estimated geometric DVF uncertainty, the dose gradient of fractional recalculated dose distribution and the direction factor from the applied reference DIR of this fraction. This estimated dose uncertainty was respectively compared to the reference dose uncertainty when different DIRs were applied individually for each dose warping. This approach was validated on seven NSCLC patients, each with nine repeated CTs. The proposed model-based method is able to achieve dose uncertainty distribution on a conservative voxel-to-voxel comparison within +/- 5% of the prescribed dose to the 'reference' dosimetric uncertainty, for 77% of the voxels in the body and 66%-98% of voxels in investigated structures. We propose a method to estimate DIR induced uncertainties in dose accumulation for proton therapy of lung tumor treatments
Evaluation of interplay and organ motion effects by means of 4D dose reconstruction and accumulation
PURPOSE: Pencil beam scanned proton therapy (PBS-PT) treatment quality might be compromised by interplay and motion effects. Via fraction-wise reconstruction of 4D dose distributions and dose accumulation, we assess the clinical relevance of motion related target dose degradation in thoracic cancer patients. METHODS AND MATERIALS: For the ten thoracic patients (Hodgkin lymphoma and non-small cell lung cancer) treated at our proton therapy facility, daily breathing pattern records, treatment delivery log-files and weekly repeated 4DCTs were collected. Patients exhibited point-max target motion of up to 20 mm. They received robustly optimized treatment plans, delivered with five-times rescanning in fractionated regimen. Treatment delivery records were used to reconstruct 4D dose distributions and the accumulated treatment course dose per patient. Fraction-wise target dose degradations were analyzed and the accumulated treatment course dose, representing an estimation of the delivered dose, was compared with the prescribed dose. RESULTS: No clinically relevant loss of target dose homogeneity was found in the fraction-wise reconstructed 4D dose distributions. Overall, in 97% of all reconstructed fraction doses, D98 remained within 5% from the prescription dose. The V95 of accumulated treatment course doses was higher than 99.7% for all ten patients. CONCLUSIONS: 4D dose reconstruction and accumulation enables the clinical estimation of actual exhibited interplay and motion effects. In the patients considered here, the loss of homogeneity caused by interplay and organ motion did not show systematic pattern and smeared out throughout the course of fractionated PBS-PT treatment. Dose degradation due to anatomical changes showed to be more severe and triggered treatment adaptations for five patients
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