cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Influence of ascorbic acid as a growth and differentiation factor on dental stem cells used in regenerative endodontic therapies
Creators: name: Diederich, Antje
name: Fründ, Hanna Juliane
name: Trojanowicz, Bogusz
name: Navarrete Santos, Alexander
name: Nguyen, Anh Duc
name: Hoang-Vu, Cuong
name: Gernhardt, Christian
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2023
Subjects: subject: 610

description: Background: Vitamin C is one of the major extracellular nonenzymatic antioxidants involved in the biosynthesis of collagen. It promotes the growth of fibroblasts, wound healing processes, and enhances the survival and differentiation of osteoblasts. The potential effects of ascorbic acid on human dental pulp cells (DPC) and the cells of the apical papilla (CAP) used in actual regenerative endodontic procedures remain largely unknown. In this study, we investigated the possible employment of ascorbic acid in the differentiation and regenerative therapies of DPC and CAP. Methods: Nine extracted human wisdom teeth were selected for this study. Subpopulations of stem cells within DPC and CAP were sorted with the mesenchymal stem cell marker STRO-1, followed by treatments with different concentrations (0 mM, 0.1 mM, 0.5 mM, and 1.0 mM) of ascorbic acid (AA), RT-PCR, and Western blot analysis. Results: FACS analysis revealed the presence of cell subpopulations characterized by a strong expression of mesenchymal stem cell marker STRO-1 and dental stem cell markers CD105, CD44, CD146, CD90, and CD29. Treatment of the cells with defined amounts of AA revealed a markedly increased expression of proliferation marker Ki-67, especially in the concentration range between 0.1 mM and 0.5 mM. Further investigations demonstrated that treatment with AA led to significantly increased expression of common stem cell markers OCT4, Nanog, and Sox2. The most potent proliferative and expressional effects of AA were observed in the concentration of 0.1 mM. Conclusions: AA might be a novel and potent growth promoter of human dental cells. Increasing the properties of human dental pulp cells and the cells of the apical papilla using AA could be a useful factor for further clinical developments of regenerative endodontic procedures.
GMF: A Model Migration Case for the Transformation Tool Contest
Creators: name: Herrmannsdoerfer, Markus
Publisher: name: arXiv
Year: 2011
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: Using a real-life evolution taken from the Graphical Modeling Framework, we invite submissions to explore ways in which model transformation and migration tools can be used to migrate models in response to metamodel adaptation.
description: In Proceedings TTC 2011, arXiv:1111.4407
Learners’ characteristics and the mastery of digital education during the COVID-19 pandemic in students of a medical faculty in Germany
Creators: name: Roick, Julia
name: Poethke, Paul
name: Richter, Matthias
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2023
Subjects: subject: 610

description: Background: In response to the spread of the coronavirus, educational institutions have been closed and digital education has become a new teaching method to ensure the continuity of medical education. Since this format was a new form of learning for students at medical faculties in Germany, little is known about the perception of it and the factors that contribute to successful mastery. The current study aimed to analyze students’ learning experiences during the first online semester and to identify associations between learners’ characteristics and enjoyment, mastery experiences, as well as the perceived stress level. Methods: In this cross-sectional study, students of a medical faculty from Germany answered an online questionnaire including information about perceptions towards digital education and learners’ characteristics (study skills and dispositions). Data were analyzed using multivariate linear regression analysis. Results: In total, 383 students responded to the online survey. A majority of students felt at least somewhat worse about their studies compared to before the pandemic. Success of study tasks was related to preferences for cooperative learning (B = − 0.063, p < .001) and success of study organization was associated to the use of metacognitive learning strategies (B = 0.019, p = .04). Enjoyment of studying in times of digital education was positively related to the use of metacognitive strategies (B = 0.049, p = .04) and self-efficacy (B = 0.111, p = .02). The perceived stress was influenced by cognitive strategies (B = 0.401, p = .02) and test anxiety (B = 0.466, p < .001). Conclusions: Although students perceive digital teaching as a good alternative for big courses, those with low self-efficacy beliefs and low self-regulation have problems in coping with the demands of this learning format and need further support.
On the continuity of optimal stopping surfaces for jump-diffusions
Creators: name: Cai, Cheng
name: De Angelis, Tiziano
name: Palczewski, Jan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Probability (math.PR)
subject: Optimization and Control (math.OC)
subject: FOS: Mathematics
subject: 60G40, 35R35, 60J60, 60J76

description: We show that optimal stopping surfaces $(t,y)\mapsto x_*(t,y)$ arising from time-inhomogeneous optimal stopping problems on two-dimensional jump-diffusions $(X,Y)$ are continuous (jointly in time and space) under mild monotonicity and regularity assumptions of local nature.
description: 18 pages, strengthened discussion of related literature
Debating human rights and the rule of law in China : international actors' role in upholding basic standards
Creators: name: Guitard, Jessica Amy
Publisher: name: University of British Columbia
Year: 2009

description: The question of linking China’s accession to international organizations such as the World Trade Organization (WTO) and its acceptance of internationally recognized standards has taken on increased visibility as China’s economic development climbs at the scale of developed countries. Although globalization has brought about important benefits to some, China’s situation differs in that the policies on human rights, including labour standards, have not been addressed successfully with its rapid transition to a market-driven economy. The purpose of this thesis is to determine the best approach to help promote internationally recognized human rights in a country that arguably does not have a rule of law system. While most see the clash between the role of civil society activists and the presence of supranational corporations in countries such as China, this thesis suggests that there is mutual complicity among those international actors. I have grouped China’s unique position internationally and its particular context in the global economy into six chapters which I have identified as the Rule of Law (Chapter 1), China’s Evolution Towards Capitalism (Chapter 2), Human Rights in China (Chapter 3), Selective Adaptation (Chapter 4), Civil Society (Chapter 5) and Corporate Social Responsibility (Chapter 6). Each Chapter is independent and discusses the various perspectives from a Western and Chinese context. Chapter 1 introduces the notion of the rule of law, as this is a fundamental concept by which liberal democracies can govern legitimately. Respect for the law and its institutions provide protection to individual citizens against the State. This concept has been obscured by China’s central government control.
Discovery of new boswellic acid hybrid 1H-1,2,3-triazoles for diabetic management : in vitro and in silico studies
Creators: name: Ur Rehman, Najeeb
name: Jan, Saeed Ullah
name: Alam, Tanveer
name: Halim, Sobia Ahsan
name: Mohanta, Tapan Kumar
name: Khan, Ajmal
name: Anwar, Muhammad Usman
name: Csuk, René
name: Avula, Satya Kumar
name: Al-Harrasi, Ahmed
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2023
Subjects: subject: 540

description: A series of 24 new 1H-1,2,3-triazole hybrids of 3-O-acetyl-11-keto-β-boswellic acid (β-AKBA (1)) and 11-keto-β-boswellic acid (β-KBA (2)) was designed and synthesized by employing “click” chemistry in a highly efficient manner. The 1,3-dipolar cycloaddition reaction between β-AKBA-propargyl ester intermediate 3 or β-KBA-propargyl ester intermediate 4 with substituted aromatic azides 5a–5k in the presence of copper iodide (CuI) and Hünig’s base furnished the desired products—1H-1,2,3-triazole hybrids of β-AKBA (6a–6k) and β-KBA (7a–7k)—in high yields. All new synthesized compounds were characterized by 1H-, 13C-NMR spectroscopy, and HR-ESI-MS spectrometry. Furthermore, their α-glucosidase-inhibitory activity was evaluated in vitro. Interestingly, the results obtained from the α-glucosidase-inhibitory assay revealed that all the synthesized derivatives are highly potent inhibitors, with IC50 values ranging from 0.22 to 5.32 µM. Among all the compounds, 6f, 7h, 6j, 6h, 6g, 6c, 6k, 7g, and 7k exhibited exceptional inhibitory potency and were found to be several times more potent than the parent compounds 1 and 2, as well as standard acarbose. Kinetic studies of compounds 6g and 7h exhibited competitive and mixed types of inhibition, with ki values of 0.84 ± 0.007 and 1.18 ± 0.0012 µM, respectively. Molecular docking was carried out to investigate the binding modes of these compounds with α-glucosidase. The molecular docking interactions indicated that that all compounds are well fitted in the active site of α-glucosidase, where His280, Gln279, Asp215, His351, Arg442, and Arg315 mainly stabilize the binding of these compounds. The current study demonstrates the usefulness of incorporating a 1H-1,2,3-triazole moiety into the medicinally fascinating boswellic acids skeleton.
Process development for the simultaneous microbial production of n-butanol and 1,3-propanediol
Creators: name: Prescher, Christin
Publisher: name: TUHH Universitätsbibliothek
Year: 2018
Subjects: subject: Prozessentwicklung
subject: Bioraffinerie
subject: N-Butanol
subject: 1,3-Propandiol
subject: Clostridium pasteurianum
classificationCode: 620
subject: Ingenieurwissenschaften

description: Diese Arbeit umfasst die Entwicklung eines biotechnologischen Prozesses, zur Herstellung von n-Butanol und 1,3-Propandiol mit Clostridium pasteurianum DSMZ 525, unter der Verwendung von nachwachsenden Rohstoffen. Dabei wurde der Einfluss von verschiedenen Substraten, Eisenverfügbarkeit im Medium, redox-aktiven Substanzen und der Einsatz von Elektrobioreaktoren untersucht. Des Weiteren wurde der Effekt von in situ Gasstripping, zur Abtrennung des inhibierend wirkenden n-Butanols, analysiert und der Prozess optimiert. Unter den besten Kultivierungsbedingungen konnten 39 g/L n-Butanol und 53 g /L 1,3-PDO hergestellt werden.
description: This thesis comprises the development of a biotechnological process for the simultaneous production of n-butanol and 1,3-propanediol with Clostridium pasteurianum DSMZ 525, growing on substrates from renewable resources. The influence of carbon sources with different reductive states, iron availability in the medium, redox active mediators and electro-bioreactors on metabolism and productivity were analyzed. For the recovery of inhibiting n-butanol, in situ gas stripping was implemented in the fermentation process and further optimized. Under the best conditions C. pasteurianum DSMZ 525 produced simultaneously 39 g/L BuOH and 53 g/L 1,3-PDO.
Prevalence and risk factors for tobacco, khat, and alcohol consumption among high school students in Ethiopia
Creators: name: Hirpa, Selamawit
name: Fogarty, Andrew W.
name: Addissie, Adamu
name: Bauld, Linda
name: Frese, Thomas
name: Unverzagt, Susanne
name: Kantelhardt, Eva Johanna
name: Getachew Kelbore, Sefonias
name: Deressa, Wakgari
Publisher: name: Universitäts- und Landesbibliothek Sachsen-Anhalt
Year: 2023
Subjects: subject: 610

description: Background: Tobacco, khat, alcohol, and marijuana are the main risk factors for non-communicable diseases. There are limited studies on substance use in Ethiopia, especially among secondary school students. This study aims to determine the epidemiology of substance use among secondary school students in Ethiopia. Methods: This cross-sectional study was conducted in March 2020 in four large regions of Ethiopia and the capital Addis Ababa. We collected data from 3,355 grade 9 and grade 10 students in 36 randomly selected high schools. Data were collected on tobacco, khat, alcohol and other substances. Mixed effect logistic regression models were fitted to determine the predictors of cigarette smoking. Results: 157 (4.7%) of the participants ever smoked cigarettes and 81 (2.4%) were current smokers. 106 (3.2%) ever used smokeless tobacco, 1,342 (41.8%) had ever drunk alcohol, 290 (8.7%) ever used khat, 137 (4.8%) chewed khat regularly and 76 (2.3%) ever used marijuana. There was a significant regional variation in substance use patterns; cigarette and khat use was the highest in southern regions, whereas alcohol use was highest in the northern areas. Availability of cigarette and khat shops within a 100-meter radius of the school compound was reported by 1,229 (37.5%) and 816 (25%) students, respectively. Three hundred fifty-four (10.9%) students had ever seen someone smoking a cigarette in the school compound. Ever use of smokeless tobacco (Adjusted Odds Ratio (AOR) = 9.4, 95%CI: 4.9–17.9), ever use of shisha (AOR = 8, 95% CI: 3.9–16.3), ever use of khat (AOR = 4.1, 95%CI: 2.5–6.8), ever use of alcohol (AOR = 2.3, 95%CI: 1.4–3.7), having a friend who smoked a cigarette (AOR = 2, 95%CI: 1.2–3.5), and ever seen someone smoking a cigarette in the school compound (AOR = 1.9, 95%CI: 1.1–3.4) were associated with ever use of cigarettes. Conclusion: Substance use prevalence in Ethiopia has regional variations and prevention strategies should be tailored to the needs of the regions. Although this study reported a lower prevalence of cigarette smoking, students could access cigarettes and khat in nearby school areas. The existing tobacco control laws that prohibit selling tobacco products to children and adolescents under 21 years of age and ban establishing tobacco shops close to school compounds should be enforced.
Deep learning for automatic lung disease analysis in chest x-rays
Creators: name: Baltruschat, Ivo-Matteo
Publisher: name: TUHH Universitätsbibliothek
Year: 2021
Subjects: subject: deep learning
subject: medical imaging
subject: machine learning
subject: X-ray
subject: convolutional neural networks
classificationCode: 610
subject: Medizin
classificationCode: 620
subject: Ingenieurwissenschaften

description: Diese Arbeit befasst sich mit der automatischen Analyse von Thorax-Röntgenbildern mithilfe von Deep Learning, einer sich schnell entwickelnden Methode des maschinellen Lernens. Nach einer detaillierten Evaluierung von CNN-Architekturen auf dem ChestX-ray14 -Datensatz wird gezeigt, wie Modelle angepasst werden können, um Nicht-Bild-Merkmale einzubeziehen und ihre Leistung zu verbessern. Um das Erscheinungsbild von CXRs zu vereinfachen und CNNs dabei zu helfen, mit hochdimensionalen und begrenzten Daten umzugehen, sowie um ihre Leistung zu verbessern, wurde eine Reihe von fortschrittlichen Vorverarbeitungsmethoden eingesetzt. Schließlich wird durch Simulationen, die auf der Warteschlangentheorie und Markov-Prozessen basieren, die signifikante Verbesserung durch intelligente Arbeitslistensortierung aufgezeigt.
description: This work addresses the automatic analysis of chest radiographs using Deep Learning, a rapidly evolving machine learning method. After a detailed evaluation of state-of-the-art CNN architectures on the ChestX-ray14 dataset, it is shown how models can be adapted to incorporate non-image features and improve their performance. Further, to simplify the appearance of CXRs and help CNNs deal with high-dimensional and limited data, as well as to improve their performance, a number of advanced pre-processing methods have been employed. Lastly, through simulations based on queuing theory and Markov processes, the significant clinical impact of smart worklist ordering is shown.
Cyclic Correlation of Diffuse Reflected Signal with Glucose Concentration and scatterer size
Creators: name: Solanki, Jitendra
name: Sen, Pratima
name: Andrews, Joseph Thomas
name: Thareja, Kamal Kishore
Publisher: name: arXiv
Year: 2012
Subjects: subject: Medical Physics (physics.med-ph)
subject: Biological Physics (physics.bio-ph)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The utility of optical coherence tomography signal intensity for measurement of glucose concentration has been analysed in tissue phantom and blood samples from human subjects. The diffusion equation based calculations as well as in-vivo OCT signal measurements confirms the cyclic correlation of signal intensity with glucose concentration and scatterer size.
description: Four figures, Five pages
Qualification of SLM : additive manufacturing for aluminium
Creators: name: Schmidtke, Katja
Publisher: name: TUHH Universitätsbibliothek
Year: 2020
Subjects: subject: Additive Manufacturing (AM)
subject: aluminium alloy
subject: powder
subject: material testing
subject: aerospace
subject: Scalmalloy
subject: SilmagAl
classificationCode: 600
subject: Technik
classificationCode: 620
subject: Ingenieurwissenschaften

description: In der vorliegenden Dissertation “Qualification of SLM - Additive Manufacturing for Aluminium Alloys” wird die Eignung von Aluminiumlegierungen für die additive Fertigungstechnik Selektives Laserstrahlschmelzen (SLM) betrachtet. Der SLM - Prozess bietet Abkühlraten, die völlig neue Optionen für Aluminiumlegierungen ermöglichen. Die Untersuchungen vertiefen das wissenschaftliche Verständnis der, auf das SLM Verfahren zugeschnittenen, Al-Legierungen Scalmalloy und SilmagAl. Verschiedene Aspekte der Prozesskette werden hinsichtlich der Definition von Pulver- und Materialspezifikationen für Luft- und Raumfahrtanwendungen beschrieben, analysiert und diskutiert. Prozessbeeinflussende Pulvereigenschaften werden identifiziert und Möglichkeiten zur Charakterisierung werden diskutiert. Der additiv gefertigte Werkstoff beider Legierungen wird umfassend auf dessen mechanische und physikalische Eigenschaften untersucht. Damit wird der Reifegrad dieser beiden Aluminiumlegierungen erhöht um die zeit- und kostenintensive Luft- und Raumfahrtqualifikationen zu beschleunigen. Prozesswege werden identifiziert mit denen die vorgeschlagenen Materialspezifikationen für verschieden Bauteil aus der Flugzeugstrukur erreicht werden können.
description: The present Thesis "Qualification of SLM - Additive Manufacturing for Aluminium Alloys" considers the suitability of two aluminum alloys for the additive manufacturing technique Selective Laserbeam Melting (SLM). High cooling rates can be realised in SLM which allow the use of the tailored Al-alloy options Scalmalloy and SilmagAl. The investigations deepen the scholarly understanding of processing both alloys in SLM. Different aspects of the process chain are described, analysed and discussed with regard to define powder and material specifications for aerospace applications. Main process influencing powder characteristics are identified and characterising techniques are discussed. The additive manufactured material of both alloys is comprehensively investigated regarding mechanical and physical properties. As result, different processing routes are identified which aim to meet the final proposed material specification for principle structural elements (PSE) and non-principle structural elements (non-PSE) in aerospace qualifications.
The very-high energy emission from pulsars: a case for inverse Compton scattering
Creators: name: Lyutikov, Maxim
name: Otte, Nepomuk
name: McCann, Andrew
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The observations of gamma-ray emission from pulsars with the Fermi-LAT detector and the detection of the Crab pulsar with the VERITAS array of Cherenkov telescopes at energies above 100 GeV make it unlikely that curvature radiation is the main source of photons above GeV energies in the Crab and many other pulsars. We outline a model in which the broad UV-X-ray component and the very high energy γ-ray emission of pulsars are explained within the Synchrotron-Self-Compton (SSC) framework. We argue that the bulk of the observed radiation is generated by the secondary plasma, which is produced in cascades in the outer gaps of the magnetosphere. We find that the inverse-Compton (IC) scattering occurs in the Klein-Nishina regime, which favors synchrotron photons in the UV band as target field for the scattering process. The primary beam is accelerated in a modest electric field, with a field strength that is of the order of a few percent of the magnetic field near the light cylinder. Overall, in the Klein-Nishina regime of the IC scattering the particle distribution in the gap does not evolve towards a stationary distribution and thus is intrinsically time-dependent. We point out that in a radiation reaction-limited regime of particle acceleration the gamma-ray luminosity L_γ scales linearly with the pulsar spin-down power \dot{E}, L_γ~ \dot{E}, and not proportional to \sqrt{\dot{E}} as expected from potential-limited acceleration.
description: 15 pages, 1 figure
Energy dependence of inclusive photon elliptic flow in heavy-ion collision models
Creators: name: Singh, Ranbir
name: Nasim, Md.
name: Mohanty, Bedangadas
name: Sambyal, Sanjeev Singh
Publisher: name: arXiv
Year: 2012
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We present a comparison of inclusive photon elliptic flow parameter (v_{2}) measured at RHIC and SPS high energy heavy-ion collision experiments to calculations done using the AMPT and UrQMD models. The new results discussed includes the comparison of the model calculations of photon v_{2} to corresponding measurements at the forward rapidities. We observe that the AMPT model which includes partonic interactions and quark coalescence as a mechanism of hadronization is in good agreement with the measurements even at forward rapidities (2.3 < η< 3.9) at RHIC as was previously observed for measurements at midrapidity. At the top SPS energy the contribution from partonic effects are smaller than that at RHIC energy, based on the comparison of the measured photon v_{2} with those from the AMPT default and UrQMD model calculations. We find that if the measurements in RHIC beam energy scan (BES) and LHC energies would require an energy dependent partonic cross section in the AMPT models, then the observed longitudinal scaling of v_{2} at top RHIC energies (19.6-200 GeV) will be violated. We also discuss the relation between the inclusive photon v_{2} and those of their parent π^{0}'s for the beam energies of 7.7 GeV to 2.76 TeV. The model results show that the transverse momentum (p_{\mathrm T}) integrated v_{2} of π^{0} is larger by about 44% relative to those of the inclusive photons. Finally we present the expectations of inclusive photon v_{2} for the RHIC beam energy scan (BES) program and LHC from the transport models, so that they can be compared to corresponding measurements using the data already collected at RHIC and LHC.
description: 15 pages and 14 figures. Accepted for publication in Journal of Physics G
Entwicklung einer faseroptischen Bandwaage für den Einsatz in Recyclinganlagen
Creators: name: Gönner, Alexander
Publisher: name: TU Dortmund
Year: 2023
Subjects: subject: Faser-Bragg-Gitter
subject: Kreislaufwirtschaft
subject: Bandwaage
subject: 710
subject: Kreislaufwirtschaft
subject: Bandwaage

description: Um die Automatisierung in der Recyclingindustrie voranzutreiben, ist eine zuverlässigere Überwachung der stattfindenden Prozessschritte und des verarbeiteten Materialstroms erforderlich. Der verstärkte Einsatz von Bandwaagen ist eine Möglichkeit, dieser Herausforderung zu begegnen. Herkömmliche Bandwaagen sind für diesen Zweck jedoch zu ungenau, unflexibel und kostspielig. Ziel dieser Arbeit ist es daher, eine alternative Bandwaage zu entwickeln, die durch den Einsatz von faseroptischen Technologien verbesserte Eigenschaften aufweist. Der aktuelle Stand von Wissenschaft und Technik wird genutzt, um Messverfahren und -methoden speziell für diese Anwendung zu entwickeln und zu erproben. Die Ergebnisse zeigen, dass die faseroptische Bandwaage in Recyclinganlagen vielseitiger und zuverlässiger eingesetzt werden kann und ein positiver Skaleneffekt zu reduzierten Stückkosten führt. Diese Vorteile heben die faseroptische Bandwaage von herkömmlichen Bandwaagen ab, so dass sie in Recyclinganlagen wirtschaftlicher und ressourcenschonender eingesetzt werden kann.
Lipschitz Functions on Expanders are Typically Flat
Creators: name: Peled, Ron
name: Samotij, Wojciech
name: Yehudayoff, Amir
Publisher: name: arXiv
Year: 2012
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics
subject: 60C05

description: This work studies the typical behavior of random integer-valued Lipschitz functions on expander graphs with sufficiently good expansion. We consider two families of functions: M-Lipschitz functions (functions that change by at most M along edges) and integer-homomorphisms (functions that change by exactly 1 along edges). We prove that such functions typically exhibit very small fluctuations. For instance, we show that a uniformly chosen M-Lipschitz function takes only M+1 values on most of the graph, with a double exponential decay for the probability to take other values.
description: 26 pages
Zur Modellierung des Transports kohäsiver Sedimente am Beispiel des Weserästuars
Creators: name: Hesse, Roland
Publisher: name: TUHH Universitätsbibliothek
Year: 2020
Subjects: subject: Kohäsive Sedimente
subject: Transport suspendierter Sedimente
subject: Bodenaustausch
subject: Sedimenttransportlimitation
subject: 2-Layer-Concept
subject: Trübungszone
subject: Ästuarines Trübungsmaximum
subject: Saisonale Sedimentdynamik
subject: Unterhaltungsbaggerung
subject: Weserästuar
subject: numerische Modellierung
subject: Delft3d
classificationCode: 550
subject: Geowissenschaften
classificationCode: 600
subject: Technik
classificationCode: 620
subject: Ingenieurwissenschaften
classificationCode: 710
subject: Landschaftsgestaltung, Raumplanung

description: Kohäsive Sedimente weisen im Vergleich zu anderen Sedimentfraktionen ein deutlich abweichendes hydrodynamisches Transportverhalten auf. Dies führt in Kombination mit residualen Strömungs- und Durchmischungsprozessen in Ästuaren zur Ausbildung der sog. Ästuarinen Trübungszone. Ein neuer, prozessbasierter Modellansatz wird vorgestellt, der die anwendungsbezogene Abbildung der Dynamik der kohäsiven Sedimentfraktion für die ästuarine Umgebung mit numerischen Verfahren erlaubt. Der Ansatz wurde für das Weserästuar getestet. Die modellierte Trübungszone ergibt sich im Modell wie in der Natur als dynamisches Gleichgewicht aufgrund der Sedimentakkumulation.
description: Cohesive Sediments show in comparison to other sediment fractions a differing hydrodynamic transport behaviour. This leads in combination with occurring residual flow and mixing processes in estuaries to the formation of the so-called estuarine turbidity zone. A new process-based model approach is presented, which enables the applied modelling of the dynamics of cohesive sediments for the estuarine environment with numeric methods. The approach was tested for the Weser estuary. The modelled turbidity zone is establishing in the model like in nature as a dynamic equilibrium due to the sediment accumulation.
Nonlinear self-adjointness and conservation laws
Creators: name: Ibragimov, Nail H.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences
subject: 35G20, 35L65, 58J70

description: The general concept of nonlinear self-adjointness of differential equations is introduced. It includes the linear self-adjointness as a particular case. Moreover, it embraces the strict self-adjointness and quasi self-adjointness introduced earlier by the author. It is shown that the equations possessing the nonlinear self-adjointness can be written equivalently in a strictly self-adjoint form by using appropriate multipliers. All linear equations possess the property of nonlinear self-adjointness, and hence can be rewritten in a nonlinear strictly self-adjoint. For example, the heat equation $u_t - Δu = 0$ becomes strictly self-adjoint after multiplying by $u^{-1}.$ Conservation laws associated with symmetries can be constructed for all differential equations and systems having the property of nonlinear self-adjointness.
A comparative study of cultured and field plants provides evidence for the shy male hypothesis in tropical genotypes of Bryum argenteum Hedw.
Creators: name: dos Santos, Wagner Luiz
name: Pôrto, Kátia Cavalcanti
name: Greenwood, Joshua
name: Davis, Andie
name: Pinheiro, Fábio
name: Stark, Lloyd R.
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Evolutionary Biology
subject: FOS: Biological sciences
subject: Ecology
subject: Sociology
subject: FOS: Sociology
subject: Biological Sciences not elsewhere classified
subject: Developmental Biology
subject: Infectious Diseases
subject: FOS: Health sciences

description: The female-biased sex ratio is recurrently observed in bryophyte populations, although the sex ratio of spores is usually balanced. The results of several studies have suggested explanations for this observation, one of which is the shy male hypothesis. The shy male hypothesis predicts that the sex ratio of populations is balanced in the field, but due to a low or lack of sex expression of male plants, the populations present a female bias when the sex ratio is based on observations of sex-expressing plants. We tested the shy male hypothesis using samples of the moss Bryum argenteum collected from Brazilian seasonally dry tropical forests and the Brazilian Atlantic Forest. Field sex ratios were determined by classifying shoots as male, female, or non–sex-expressing. Non–sex-expressing shoots were further analysed for sex expression after culture regeneration. Our results showed that populations of Bryum argenteum in the field had a low rate of sex expression, and that most of the shoots expressed were female. However, when shoots without sex expression were cultured, a greater number of male shoots were observed compared with in the field plants. Because more males appeared in the shoots cultured from non–sex-expressing field plants, our data for tropical B. argenteum tend to support the shy male hypothesis. Some genotypes from the wet forest were synoicous (i.e. had male and female gametangia in the same gametoecia), suggesting polyploidy.
Airy sheaves for reductive groups
Creators: name: Jakob, Konstantin
name: Kamgarpour, Masoud
name: Yi, Lingfei
Publisher: name: arXiv
Year: 2021
Subjects: subject: Algebraic Geometry (math.AG)
subject: Number Theory (math.NT)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 14D24, 20G25, 22E50, 22E67

description: We construct a class of $\ell$-adic local systems on $\mathbb{A}^1$ that generalizes the Airy sheaves defined by N. Katz to reductive groups. These sheaves are finite field analogues of generalizations of the classical Airy equation $y''(z)=zy(z)$. We employ the geometric Langlands correspondence to construct the sought-after local systems as eigenvalues of certain rigid Hecke eigensheaves, following the methods developed by Heinloth, Ngô and Yun. The construction is motivated by a special case of Adler and Yu's construction of tame supercuspidal representations. The representations that we consider can be viewed as deeper analogues of simple supercuspidals. For $\mathrm{GL}_n$, we compute the Frobenius trace of the local systems in question and show that they agree with Katz's Airy sheaves. We make precise conjectures about the ramification behaviour of the local systems at $\infty$. These conjectures in particular imply cohomological rigidity of Airy sheaves.
description: 30 pages
Thermoregulation and roost selection by reproductive big brown bats (Eptesicus fuscus) roosting in the South Saskatchewan River Valley, Alberta: rock-roosting and building-roosting colonies
Creators: name: Lausen, Cori Lorraine
Publisher: name: Graduate Studies
Year: 2001
Subjects: subject: AC1 .T484 2001 L38

description: Bibliography: p. 108-117
Computing interior eigenvalues of medium sized generalized symmetric eigenproblems
Creators: name: Mackens, Wolfgang
name: Voß, Heinrich
Publisher: name: TUHH Universitätsbibliothek
Year: 1999
Subjects: subject: Generalized Eigenvalue Problem, Projection Method
subject: Rational Krylov Space
subject: Error Estimation
subject: Shift-Invert Strategy
classificationCode: 510
subject: Mathematik
subject: Eigenwertproblem
subject: Projektionsverfahren
classificationCode: 65F15
subject: Eigenvalues, eigenvectors

description: We present an algorithmic framework to compute approximations to all eigenvalues of a generalized symmetric eigenvalue problem in a prespecified interval together with rigorous error bounds. The method needs the computation of some LU factorizations of the incorporated matrices. The ability to do this excludes the treatment of very large problems.
Relativistic Stark resonances in a simple exactly soluble model for a diatomic molecule
Creators: name: Fillion-Gourdeau, Francois
name: Lorin, Emmanuel
name: Bandrauk, Andre D.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: A simple 1-D relativistic model for a diatomic molecule with a double point interaction potential is solved exactly in a constant electric field. The Weyl-Titchmarsh-Kodaira method is used to evaluate the spectral density function, allowing the correct normalization of continuum states. The boundary conditions at the potential wells are evaluated using Colombeau's generalized function theory along with charge conjugation invariance and general properties of self-adjoint extensions for point-like interactions. The resulting spectral density function exhibits resonances for quasibound states which move in the complex energy plane as the model parameters are varied. It is observed that for a monotonically increasing interatomic distance, the ground state resonance can either go deeper into the negative continuum or can give rise to a sequence of avoided crossings, depending on the strength of the potential wells. For sufficiently low electric field strength or small interatomic distance, the behavior of resonances is qualitatively similar to non-relativistic results.
description: 37 pages, 30 figures
Mechanical characteristics in impaction allografting - the role of graft density and cement penetration profile
Creators: name: Albert, Carolyne Izabel
Publisher: name: University of British Columbia
Year: 2009

description: Revision total hip arthroplasty with femoral impaction allografting has an attractive potential for restoring bone stock in femurs with bone loss caused by the failure of hip implants. However, problematic implant subsidence is often reported after this procedure. A lack of understanding remains over the mechanisms that cause subsidence. The objectives of this study were to: a) explore the relationships between subsidence and morphometric features of the graft and bone cement regions after femoral impaction allografting in a cadaveric femur model; b) characterize mechanical properties of the graft bed as a function of impaction force, and explore new alternative graft compaction methods; and c) develop a finite element model to investigate the key mechanisms that contribute to initial implant subsidence. High levels of cement penetration into the graft bed were observed, resulting in extensive regions of cement contact with the host bone in a cadaveric femur model. The implant subsidence correlated negatively with the amount of cement-endosteum contact. The density, compression stiffness and shear strength of the graft were proportional to the impaction force. A slower alternative graft compaction method resulted in higher graft stiffness and shear strength than traditional graft impaction, but the benefit of this new compaction method was small compared to the effect of increasing the impaction force. In a finite element model, the relationship between graft density and subsidence was dependant on cement penetration profile. Without cement-endosteum contact, subsidence decreased with increasing graft density; however, graft density did not affect subsidence in constructs with cement-endosteum contact. Initial subsidence was primarily attributed to slippage at the stem-cement and endosteum interfaces, and the latter mechanism was greatly affected by changes in graft density and cement penetration profile. This study demonstrated that extensive cement penetration can occur in femoral impaction allografting, which may compromise the potential for new bone formation but may be important in preventing excessive subsidence. The endosteum interface was identified as a key factor in the development of subsidence. Finally, our results indicate that the potential benefit of achieving a denser graft bed depends upon the cement penetration profile.
ASSESSMENT OF RAILWAY BRIDGE DESIGN AND CONSTRUCTION:CASE STUDY OF ADDIS ABABA LIGHT RAIL TRANSIT PROJECT
Creators: name: Kassahun Abebe Nadew
Publisher: name: Zenodo
Year: 2016

description: Urban rail transit is an all-encompassing term for various types of local rail systems

providing passenger service within and around urban or suburban areas. Many of this

urban rail transit system encompass different types of aerial structures/bridges. Apart

from similar highway bridges, fulfilling all the design and construction requirements,

Railway aerial structures come in many forms, and each has a different level of

interaction with the tracks carried.

Addis Ababa light rail project is currently under construction by Chinese contractors

(CREC: China railway engineering corporation).which is the first in the country of its

kind as far as light railway transit system is concerned.

The research mainly focus at assessing of the design approach of different design

standards and improved construction methods in a manner to suitably fit our existing

conditions
Compiler Optimization: A Case for the Transformation Tool Contest
Creators: name: Buchwald, Sebastian
name: Jakumeit, Edgar
Publisher: name: arXiv
Year: 2011
Subjects: subject: Programming Languages (cs.PL)
subject: FOS: Computer and information sciences

description: An optimizing compiler consists of a front end parsing a textual programming language into an intermediate representation (IR), a middle end performing optimizations on the IR, and a back end lowering the IR to a target representation (TR) built of operations supported by the target hardware. In modern compiler construction graph-based IRs are employed. Optimization and lowering tasks can then be implemented with graph transformation rules. This case provides two compiler tasks to evaluate the participating tools regarding performance.
description: In Proceedings TTC 2011, arXiv:1111.4407
Ein Finite-Volumen-Verfahren zur Berechnung turbulenter Schiffsumströmungen
Creators: name: Cura Hochbaum, Andrés
Publisher: name: TUHH Universitätsbibliothek
Year: 1993
Subjects: subject: Finite-Volumen-Verfahren
classificationCode: 52.00
subject: Maschinenbau, Energietechnik, Fertigungstechnik: Allgemeines
subject: Turbulenz
subject: Umströmung
subject: Turbulente Strömung
subject: Finite-Volumen-Methode

description: Ein Finite-Volumen-Verfahren zur Berechnung turbulenter Schiffsumströmungen Es wird ein Verfahren zur Berechnung turbulenter Schiffsumströmungen beschrieben und seine Möglichkeiten durch den Vergleich mit experimentellen Daten untersucht. Die Reynolds-gemittelten Navier-Stokes-Gleichungen und die Kontinuitätsgleichung in den kartesischen Geschwindigkeitskomponenten werden nach einem Finite- Volumen- Verfahren auf einem randangepaßten Gitter diskretisiert. Ein strukturiertes 3D-Gitter für das gesamte Rechengebiet wird numerisch erzeugt. Es wird ein algebraisches Turbulenzmodell angewendet und auf die Benutzung von Wandfunktionen verzichtet. Die Konvektionsterme werden durch ein Stromauf-Differenzenschema 2. Ordnung (LUDS) und die Diffusionsterme durch zentrale Differenzen (CDS) approximiert. Zur Vermeidung von numerisch bedingten Druckoszillationen aufgrund der gewählten nichtversetzten Anordnung der Strömungsvariablen im Gitter wird eine spezielle Interpolationstechnik der Massenflüsse nach Rhie und Chow eingesetzt. Das resultierende nichtlineare algebraische Gleichungssystem wird nach der SIMPLE-Methode iterativ gelöst. Die wegen des teilweise stark nichtorthogonalen Gitters mit extremen ellseitenverhältnissen nicht zu vernachlässigenden Quergradiententerme der Druckkorrekturgleichungen werden in einer zweiten Druckkorrektur berücksichtigt. Das Verfahren wird auf den Fall eines bei konstanter Geschwindigkeit geradeaus fahrenden Schiffsmodells, ohne Berücksichtigung der freien Oberfläche, angewendet. Es werden nur Hinterschiffsumströmungen berechnet. Die Ergebnisse für das Wigley-Schiff und den HSV A- Tanker zeigen in vieler Hinsicht gute Übereinstimmung mit Experimenten. Der Modellwiderstand und der Propellerzustrom können noch nicht mit ausreichender Genauigkeit vorhergesagt werden
Complex absorbing potential method for Stark resonances
Creators: name: Kameoka, Kentaro
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mathematical Physics (math-ph)
subject: Spectral Theory (math.SP)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 81U24 (Primary) 81Q12 (Secondary)

description: We characterize the resonances of Stark Hamiltonians by the complex absorbing potential method. Namely, we prove that the Stark resonances are the limit points of complex eigenvalues of the Stark Hamiltonian with a quadratic complex absorbing potential when the absorbing coefficient tends to zero. The proof employs the complex distortion outside a cone introduced in the previous work by the author. Potentials with local singularities such as the Coulomb potential are allowed as perturbations.
description: 14 pages
Expectation of forward-backward rapidity correlations in $p+p$ collisions at the LHC energies
Creators: name: Dash, Ajay Kumar
name: Mahapatra, Durga Prasad
name: Mohanty, Bedangadas
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Forward-backward correlation strength ($b$) as a function of pesudorapidity intervals for experimental data from $p+\bar{p}$ non-singly diffractive collisions are compared to PYTHIA and PHOJET model calculations. The correlations are discussed as a function of rapidity window ($Δη$) symmetric about the central rapidity as well as rapidity window separated by a gap ($η_{gap}$) between forward and backward regions. While the correlations are observed to be independent of $Δη$, it is found to decrease with increase in $η_{gap}$. This reflects the role of short range correlations and justifies the use of $η_{gap}$ to obtain the accurate information about the physics of interest, the long range correlations. The experimental $b$ value shows a linear dependence on $\ln \sqrt{s}$ with the maximum value of unity being reached at $\sqrt{s}$ = 16 TeV, beyond the top LHC energy. However calculations from the PYTHIA and PHOJET models indicate a deviation from linear dependence on $\ln \sqrt{s}$ and saturation in the $b$ values being reached beyond $\sqrt{s}$ = 1.8 TeV. Such a saturation in correlation values could have interesting physical interpretations related to clan structures in particle production. Strong forward-backward correlations are associated with cluster production in the collisions. The average number of charged particles to which the clusters fragments, called the cluster size, are found to also increase linearly with $\ln \sqrt{s}$ for both data and the models studied. The rate of increase in cluster size vs. $\ln \sqrt{s}$ from models studied are larger compared to those from the data and higher for PHOJET compared to PYTHIA. Our study indicates that the forward-backward measurements will provide a clear distinguishing observable for the models studied at LHC energies.
description: 15 pages, 14 Figures, accepted for publication in International Journal of Modern Physics A
Hole spin relaxation in $p$-type (111) GaAs quantum wells
Creators: name: Wang, L.
name: Wu, M. W.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Hole spin relaxation in $p$-type (111) GaAs quantum wells is investigated in the case with only the lowest hole subband, which is heavy-hole like in (111) GaAs/AlAs and light-hole like in (111) GaAs/InP quantum wells, being relevant. The subband Löwdin perturbation method is applied to obtain the effective Hamiltonian including the Dresselhaus and Rashba spin-orbit couplings. Under a proper gate voltage, the total in-plane effective magnetic field in (111) GaAs/AlAs quantum wells can be strongly suppressed in the whole momentum space, while the one in (111) GaAs/InP quantum wells can be suppressed only on a special momentum circle. The hole spin relaxation due to the D'yakonov-Perel' and Elliott-Yafet mechanisms is calculated by means of the fully microscopic kinetic spin Bloch equation approach with all the relevant scatterings explicitly included. For (111) GaAs/AlAs quantum wells, extremely long heavy-hole spin relaxation time (upto hundreds of nanoseconds) is predicted. In addition, we predict a pronounced peak in the gate-voltage dependence of the heavy-hole spin relaxation time due to the D'yakonov-Perel' mechanism. This peak origins from the suppression of the unique inhomogeneous broadening in (111) GaAs/AlAs quantum wells. Moreover, the Elliott-Yafet mechanism influences the spin relaxation only around the peak area due to the small spin mixing between the heavy and light holes in quantum wells with small well width. We also show the anisotropy of the spin relaxation. In (111) GaAs/InP quantum wells, a mild peak, similar to the case for electrons in (111) GaAs quantum wells, is also predicted in the gate-voltage dependence of the light-hole spin relaxation time. The contribution of the Elliott-Yafet mechanism is always negligible in this case.
description: 9 pages, 4 figures