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Web-based Prostate Visualization Tool
Get PDFProper treatment of prostate cancer is essential to increase the survival chance. In this sense, numerous studies show how important the communication between all stakeholders in the clinic is. This communication is difficult because of the lack of conventions while referring to the location where a biopsy for diagnosis was taken. This becomes even more challenging taking into account that experts of different fields work on the data and have different requirements. In this paper a web-based communication tool is proposed that incorporates a visualization of the prostate divided into 27 segments according to the PI-RADS protocol. The tool provides 2 working modes that consider the requirements of radiologist and pathologist while keeping it consistent. The tool comprises all relevant information given by pathologists and radiologists, such as, severity grades of the disease or tumor length. Everything is visualized using a colour code for better undestanding
Experimentelle und rechnerisch validierte Methode zur Bestimmung der Mindesteinschraubtiefe von Schraubenverbindungen mit gefurchtem Mutterngewinde
Get PDFDie Einschraubtiefe und die Größe des Vorlochdurchmessers bestimmen neben dem Scherfestigkeitsverhältnis der eingesetzten Werkstoffe die quasi-statische Beanspruchbarkeit von Schraubenverbindungen mit gefurchtem Gewinde. Zur Validierung eines neuen Bewertungsansatzes zur Bestimmung der erforderlichen Mindesteinschraubtiefe werden Auszugsversuche mit variierter Einschraubtiefe und Gewindeüberdeckung für verschiedene Gewindetypen und Gewindegrößen durchgeführt. In Form des Beanspruchbarkeitsverhältnisses eines perfekt ausgeformten Gewindes und dem eines zu bewertenden Gewindes wird die Gewindeflankenüberdeckung des gefurchten Mutterngewindes in der Auslegung der erforderlichen Mindesteinschraubtiefe berücksichtigt
Tailoring charge transport in BaTiO₃ crystals through dislocation engineering
No full textDislocations in oxide ceramics significantly influence their physical properties by creating substantial local strain fields, new electronic states, and space‐charge layers. In this study, we investigated the effects of mechanically introduced dislocations on the electrical conductivity of BaTiO₃ single crystals. High‐temperature plastic deformation was employed to introduce a high dislocation density with a {100} 〈100〉 slip system. Impedance measurements revealed a significant anisotropy in the conductivity due to the presence of oriented dislocation structures. The crystals with dislocation lines aligned parallel to the measurement axis ([001] crystallographic direction) exhibited 16‐fold higher conductivity compared to those measured across the dislocations. Compared to the pristine crystals, this means an increase in conductivity when the measurements were carried out parallel to dislocation lines and a decrease in perpendicular measurements. Our study demonstrates that not only ferroelectric properties but also charge transport can be modified by dislocation introduction in BaTiO₃
Adaptive Replay-to-Sim Approach for Developing and Testing Automated Driving Systems in Urban Areas
No full textThe absence of a generally accepted approach for proving the safety of automated driving systems (ADS) motivates ongoing research into new development, testing, and validation methods meeting the efficiency and effectiveness requirements for a series release of these systems. A promising approach in academia and industry to address this challenge is scenario-based development and testing. Following the paradigm of this approach, the enormously high (in principle infinite) number of traffic situations the ADS must cope with in its operational design domain (ODD) must be transformed into a finite set of relevant traffic scenarios for subsequent testing. Additionally, a high amount of the test effort is shifted to simulation-based approaches ranging from model-in-the-loop over various X-in-the-loop test methods to real-world test driving on proving grounds and public roads. While research into proving safety for ADS has primarily been focused on highway applications (e.g., a Highway Chauffeur function) in recent years, both the definition of "relevant" scenarios and a commonly accepted methodology for deriving a scenario database of sufficient ODD coverage are subject of ongoing research. Simulation-based approaches have inherent advantages in efficient and reproducible test case execution and can already be applied in early development stages. However, simulation results can only be considered for safety-critical applications if evidence has been provided that the simulation represents the reality of interest for the given application purpose (i.e., the ADS-equipped vehicle in relevant urban traffic scenarios) sufficiently valid. Thus, to prove ADS safety, there is a demand for a holistic simulation-based test environment that enables the prediction of the open behavior of the ADS in its targeted ODD. In this context, realistically modeling all relevant stimuli to the ADS due to the (multimodal) closed-loop interaction of surrounding road users both amongst each other and with the ADS represents an essential aspect and a new challenge simultaneously. In addition, predicting ADS behavior in potentially hazardous traffic scenarios is particularly relevant. Still, due to the open ADS behavior, whether or not a traffic scenario will turn out to be hazardous or not is not known before test case execution. Thus, the availability of a simulation-based development and test environment becomes even more critical since the complexity of the required test cases makes a reproducible and, in particular, safe test case execution solely by real-world experiments impossible. This thesis proposes the so-called adaptive replay-to-sim (ARTS) approach as a novel method for developing, testing, and validating ADS. The approach is based on the adaptive hybridization of real-world data and an agent-based simulation during simulation runtime. Additionally, a functional simulation platform architecture for developing, testing, and validating ADS, focusing on urban ODDs, is presented. The ARTS approach is realized and evaluated by logically instantiating the functional simulation platform architecture in a proof-of-concept implementation. The simulation results show that ARTS merges real-world data credibility with simulative test case execution safety and flexibility while maximizing test case specification and execution efficiency. The proof-of-concept implementation leverages the results of a method for extracting potentially hazardous relevant traffic scenarios for testing ADS based on unsupervised machine learning, also conceptualized in this thesis. Finally, a validity evaluation of existing traffic simulation models to prove ADS safety in urban ODDs is performed. On this basis, a novel urban traffic agent framework is proposed whose quantitative evaluation shows a higher accuracy in modeling urban vehicular road traffic than the state of the art
How does Bayesian reverse-engineering work?
Get PDFBayesian models of cognition and behavior are particularly promising when they are used in reverse-engineering explanations: explanations that descend from the computational level of analysis to the algorithmic and implementation levels. Unfortunately, it remains unclear exactly how Bayesian models constrain and influence these lower levels of analysis. In this paper, we review and reject two widespread views of Bayesian reverse-engineering, and propose an alternative view according to which Bayesian models at the computational level impose pragmatic constraints that facilitate the generation of testable hypotheses at the algorithmic and implementation levels
Development, Characterization, Alignment and Experimental Validation of Partial Sphere Target Arrays for Advanced Proton Acceleration Studies
No full textProton Fast Ignition is an advanced Inertial Confinement Fusion scheme that is based on decoupling compression and heating of Deuterium-Tritium (DT) fuel, paving a promising path towards higher fusion energy gain with reduced laser requirements. A key challenge in Proton Fast Ignition is generating precisely tailored, high-intensity proton beams, that can deposit the necessary energy into a small volume of the pre-compressed DT fuel. This work addresses this challenge by systematically studying the focusing properties of protons accelerated via Target Normal Sheath Acceleration (TNSA) from partial sphere targets.
Past studies in this field have been comparing few target configurations with, at most, tens of shots, massively limiting the statistical evaluation of the data while impeding the exploration of target and laser parameters. To support the medium repetition rate (~1 Hz) experiments, a novel fabrication method was developed to produce 1050 partial sphere targets ranging in three sizes (Ø220 µm, Ø325 µm and Ø525 µm), an unprecedented scale in this domain. Consistent target quality was ensured through comprehensive metrology, including automated individual position measurements of 200 targets mounted in a frame. This enabled the development of a two-stage alignment procedure aimed at achieving rapid turnaround times and ensuring rapid, precise target alignment in the experimental chamber, enabling a repetition rate of 1/3Hz under optimal conditions, an unprecedented feat given the target’s complex geometry.
The partial sphere targets were shot at the L-ALEPH laser system at the Colorado State University, resulting in 320 shots across 42 different target configurations. Proton mesh radiography provided energy resolved
beam size measurements at distances of ~ 280 µm to 960 µm from the target’s apex, as well as the virtual focus position. Secondary foils, heated by the proton beam at distances of 160 µm to 320 µm from the apex, were observed by an XUV imager. This revealed that smaller, well illuminated partial spheres generated a proton beam with extended collimation, in contrast to larger partial spheres with poorer illumination. These findings validated Particle-in-Cell (PIC) simulations preceding the campaign.
This thesis demonstrates reliable large-batch fabrication and fast target alignment in the context of a comprehensive experimental study on the focusing of TNSA protons generated from partial sphere targets.
These results enable future large scale parametric studies centered on optimizing proton acceleration and focusing, contributing to the advancement of Proton Fast Ignition research by enabling large parametric studies on the new generation of high energy medium repetition rate facilities
Plant photosynthesis in basil (C3) and maize (C4) under different light conditions as basis of an AI-based model for PAM fluorescence/gas-exchange correlation
No full textPhotosynthetic activity can be monitored using pulse amplitude modulated (PAM) fluorescence or gas exchange. While PAM provides insight into the light-dependent reactions, gas exchange reflects CO₂ fixation and water balance. Accurate, non-invasive prediction of photosynthetic performance under varying conditions is highly relevant for phenotyping and stress diagnostics. Despite their physiological link, data from both methods do not always correlate. To systematically investigate this relationship, photosynthetic parameters were measured in maize (Zea mays, C4) and basil (Ocimum basilicum, C3) under different photon densities and spectral compositions. Maize showed the highest CO₂ assimilation rate of 30.99 ± 1.54 µmol CO₂/(m²s) under 2000 PAR green light (527 nm), while basil reached 10.56 ± 0.92 µmol CO₂/(m²s) under red light (630 nm). PAM-derived electron transport rates (ETR) increased with light intensity in a pattern similar to CO₂ assimilation, but did not reliably reflect its absolute values under all conditions. To improve prediction accuracy, we applied a machine learning model. XGBoost, a gradient-boosted decision tree algorithm, efficiently captures nonlinear interactions between physiological and environmental parameters. It achieved superior performance (R² = 0.847; MSE = 5.24) compared to the Random Forest model. Our model enables accurate photosynthesis prediction from PAM data across light intensities and spectral conditions in both C3 and C4 plants
Auswertung einer Befragung der ULB Darmstadt unter Lehrkräften der Oberstufe aus der Region Südhessen
No full textDienstleistungs- und Zielgruppenorientierung spielen im Alltag wissenschaftlicher Bibliotheken mittlerweile eine entscheidende Rolle. Im Gegensatz zu Hochschulbibliotheken, bei denen sich die Zielgruppen relativ klar definieren lassen, ist das Umfeld der Nutzer:innen von Regional- und Landesbibliotheken sehr heterogen. Die ULB Darmstadt erfüllt hierbei eine klassische Doppelaufgabe: Als Hochschulbibliothek ist sie für die Medienversorgung aller Angehörigen der TU Darmstadt zuständig und in ihrer Funktion als Landesbibliothek zugleich auch Ansprechpartnerin für alle interessierten Nutzer:innen aus der Region Südhessen.
Nachdem bereits die Bedürfnisse der Bürger:innen durch eine Befragung erhoben wurde, zielt diese Befragung nun auf Lehrkräfte im Speziellen ab. Gemeinsam mit der Hochschule Darmstadt führte die ULB im Sommersemester 2024 ein Forschungsprojekt durch, um mittels Onlinebefragung die folgenden Frage zu beantworten: Wie kann die ULB trotz begrenzter Personalkapazitäten effektiv sicherstellen, dass die relevanten Inhalte ihrer Veranstaltungen im Bereich Informationskompetenz möglichst viele Schüler:innen in ihrem Zuständigkeitsbereich erreichen. Die Antworten hierauf sind in dieser ausführlichen Auswertung der Befragung zu finden
Finite - Temperature topological Susceptibility of QCD with heavy Quarks
No full textThe axion is a very interesting hypothetical particle, as it is not only an ideal dark matter candidate, but also dynamically, i.e., “naturally”, solves the strong CP problem - the discrepancy between the theoretically allowed violation of the combined particle-antiparticle exchange and spatial flip-symmetry in QCD on the one hand and its experimentally observed (nearly perfect) conservation on the other hand.
“Hypothetical particle” means here that, despite significant experimental effort, the
axion has until now avoided experimental detection. Therefore, precise theoretical predictions about its properties, especially its mass, are required. Furthermore, the investigation of cosmology with axions has shown that the cosmological history of axions depends critically on the temperature-dependent axion mass in the temperature range between 400 and 1100 MeV, where very little is known about the axion mass so far.
The axion, and especially its mass, are directly linked to the topological properties of
QCD. The QCD vacuum allows for topologically non-trivial, local configurations, which do not play a role in perturbation theory, but have non-perturbative effects on the quarks and gluons. At zero temperature, these configurations are called instantons and for finite T they are called calorons. The strength of these instanton/caloron effects, i.e., the strength of the quark-gluon system’s response to such a topological background, is determined by the topological susceptibility χtop. In turn, the axion mass is proportional to the square root of χtop.
Using lattice QCD, the main model for accessing non-perturbative QCD effects, to
obtain χtop becomes very challenging at high temperatures as 400 MeV < T < 1100 MeV, because the topological susceptibility is strongly suppressed at high T and since the bottom quark is not heavy enough to ignore at such temperatures, while so far only 2+1+1, but no 2+1+1+1 (including a dynamical bottom quark) lattice simulations exist.
Therefore, we estimate the effect of the bottom quark on χtop at high temperatures
by computing the ration between the 4-quark χtop (available from lattice QCD) and the 4+1-quark χtop in the caloron gas approximation. We do this by computing small-mass and large-mass expansions of the finite-mass and -temperature fermionic fluctuation
determinant and connecting them with a Padé approximant. Together with the lattice QCD results, this allows for predictions for χtop with a bottom quark at arbitrary temperatures
Herrschaft und Ressourcenregulierung. Frühneuzeitliche Umweltgesetzgebung am Beispiel der Württembergischen Fischordnung von 1602
No full textMit dem Beginn der Frühen Neuzeit im 16. Jahrhundert ist in zahlreichen Territorien des Heiligen Römischen Reichs ein verstärktes Interesse der Obrigkeit an der Fischerei festzustellen. Die Regelung von Angelegenheiten des Fischfangs entwickelte sich zu einem Feld landesfürstlicher Betätigung, was den Erlass spezieller Fischordnungen bedingte. Umfang und Grad dieser Regulierung variierten je nach Territorium und waren von wirtschaftlichen Interessen sowie sozialen und kulturellen Faktoren beeinflusst. In einigen Ordnungen sind Bestimmungen zu finden, die als Beispiele vormoderner Umweltgesetzgebung betrachtet werden können und Ansätze eines "nachhaltigen" Umgangs mit natürlichen Ressourcen zeigen. Sie stehen in der Frühen Neuzeit im Spannungsfeld von Gewohnheitsrechten und herrschaftlichen Rechten, die als "Gute Policey" zunehmend den landesherrlichen Zugriff kennzeichnen. Beispielhaft wird dies hier anhand der Württembergischen Fischordnung von 1602 gezeigt werden