cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Shape and topology optimization in Stokes flow with a phase field approach
Creators: name: Garcke, Harald
name: Hecht, Claudia
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: Shape and topology optimization, phase field method, diffuse interfaces, Stokes flow, fictitious domain
subject: 510 Mathematik
subject: 35R35
subject: 35Q35
subject: 49Q10
subject: 49Q20
subject: 76D07

description: In this paper we introduce a new formulation for shape optimization problems in fluids in a diffuse interface setting that can in particular handle topological changes. By adding the Ginzburg{Landau energy as a regularization to the objective functional and relaxing the non-permeability outside the fluid region by introducing a porous medium approach we hence obtain a phase field problem where the existence of a minimizer can be guaranteed. This problem is additionally related to a sharp interface problem, where the permeability of the non-fluid region is zero. In both the sharp and the diffuse interface setting we can derive necessary optimality conditions using only the natural regularity of the minimizers. We also pass to the limit in the first order conditions.
Agnes Slunitschek; Thomas Bremer (Hg.), Der Glaubenssinn der Gläubigen als Ort theologischer Erkenntnis. Praktische und systematische Theologie im Gespräch (QD 304), Freiburg i. Br.: Herder 2020
Creators: name: Schröcker, Hubert
Publisher: name: Münchener Theologische Zeitschrift
Year: 2023

description: Münchener Theologische Zeitschrift, Bd. 72 Nr. 3 (2021)
Probing reionization using quasar near-zones at redshift z ~ 6
Creators: name: Padmanabhan, Hamsa
name: Choudhury, T. Roy
name: Srianand, R.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: Using hydrodynamical simulations coupled to a radiative transfer code, we study the additional heating effects in the intergalactic medium (IGM) produced by $z\sim 6$ quasars in their near-zones. If helium is predominantly in HeII to begin with, both normalization ($T_0$) and slope ($γ$) of the IGM effective equation-of-state get modified by the excess ionization from the quasars. Using the available constraints on $T_0$ at $z\sim6$, we discuss implications for the nature and epoch of HI and HeII reionization. We study the extent of the HeIII region as a function of quasar age and show, for a typical inferred age of $z \sim 6$ quasars (i.e. $\sim 10^8$ yrs), it extends up to 80% of the HI proximity region. For these long lifetimes, the heating effects can be detected even when all the HI lines from the proximity region are used. Using the flux and curvature probability distribution functions (PDFs), we study the statistical detectability of heating effects as a function of initial physical conditions in the IGM. For the present sample size, cosmic variance dominates the flux PDF. The curvature statistics is more suited to capturing the heating effects beyond the cosmic variance, even if the sample size is half of what is presently available.
description: 20 pages, 15 figures, 3 tables; version accepted for publication in MNRAS
Richard Graupner, Der Gottesdienst als Ritual. Entdeckung, Kritik und Neukonzeption des Ritualbegriffs in der evangelischen Liturgik (Evangelisch-Katholische Studien zu Gottesdienst und Predigt 5), Göttingen: Vandenhoeck & Ruprecht 2019
Creators: name: Haunerland, Winfried
Publisher: name: Münchener Theologische Zeitschrift
Year: 2023

description: Münchener Theologische Zeitschrift, Bd. 72 Nr. 3 (2021)
Probing the thermal character of analogue Hawking radiation for shallow water waves?
Creators: name: Michel, Florent
name: Parentani, Renaud
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We study and numerically compute the scattering coefficients of shallow water waves blocked by a stationary counterflow. When the flow is transcritical, the coefficients closely follow Hawking's prediction according to which black holes should emit a thermal spectrum. We study how the spectrum deviates from thermality when reducing the maximal flow velocity, with a particular attention to subcritical flows since these have been recently used to test Hawking's prediction. For such flows, we show that the emission spectrum is strongly suppressed, and that its Planckian character is completely lost. For low frequencies, we also show that the scattering coefficients are dominated by elastic hydrodynamical channels. Our numerical results reproduce rather well the observations made by S. Weinfurtner {\it et al.} in the Vancouver experiment. Nevertheless, we propose a new interpretation of what has been observed, as well as new experimental tests.
description: 23 pages, 14 figures, 2 figures updated to match the PRD version, final version published in Physical Review D
A phase field approach for shape and topology optimization in Stokes flow
Creators: name: Garcke, Harald
name: Hecht, Claudia
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: Shape and topology optimization, phase field method, diffuse interfaces, Stokes flow, fictitious domain, T-convergence
subject: 510 Mathematik
subject: 35R35
subject: 35Q35
subject: 49Q10
subject: 49Q20
subject: 76D07

description: A new formulation for shape and topology optimization in a Stokes flow is introduced. The investigated problem minimizes the total potential power of the flow. By combining a porous medium and a phase field approach we obtain a well-posed problem in a diffuse interface setting that can be reformulated into a problem without state equations. We can derive a sharp interface problem with zero permeability outside the fluid region as a T-limit of this porous medium-phase field problem.
Correlation of top asymmetries: loop versus tree origins
Creators: name: Jung, Sunghoon
name: Ko, P.
name: Yoon, Yeo Woong
name: Yu, Chaehyun
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We study the correlation of top asymmetries that are sensitive to the different origin of (a new contribution to) the total asymmetry: loop- or tree-level origins. We find that both the size and sign of the correlation between total and $t\bar{t}j$ inclusive asymmetries are inherently different depending on the origin. We demonstrate the correlation by using the color-singlet $Z^\prime$ and the pure axigluon taken as representative models of loop- and tree-induced total asymmetries. We calculate the next-to-leading order QCD corrections to the $Z^\prime$ and perform Monte-Carlo event generation. The correlation is understood in the QCD eikonal approximation using its color structure.
description: 10 pages, 7 figures; v2: layout is improved and abstract is revised, v3: published version with slight revisions
Stable numerical approximation of two-phase flow with a Boussinesq-Scriven surface fluid
Creators: name: Barrett, John W.
name: Garcke, Harald
name: Nürnberg, Robert
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: incompressible two-phase flow, surface viscosity, Boussinesq–Scriven surface fluid, finite elements, parametric method, stability
subject: 510 Mathematik
subject: 35Q35
subject: 65M12
subject: 76D05
subject: 76M10

description: We consider two-phase Navier–Stokes flow with a Boussinesq–Scriven surface fluid. In such a fluid the rheological behaviour at the interface includes surface viscosity effects, in addition to the classical surface tension effects. We introduce and analyze parametric finite element approximations, and show, in particular, stability results for semi-discrete versions of the methods, by demonstrating that a free energy inequality also holds on the discrete level. We perform several numerical simulations for various scenarios in two and three dimensions, which illustrate the effects of the surface viscosity.
Complex Statistics and Diffusion in Nonlinear Disordered Particle Chains
Creators: name: Antonopoulos, Ch. G.
name: Bountis, T.
name: Skokos, Ch.
name: Drossos, L.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: We investigate dynamically and statistically diffusive motion in a Klein-Gordon particle chain in the presence of disorder. In particular, we examine a low energy (subdiffusive) and a higher energy (self-trapping) case and verify that subdiffusive spreading is always observed. We then carry out a statistical analysis of the motion in both cases in the sense of the Central Limit Theorem and present evidence of different chaos behaviors, for various groups of particles. Integrating the equations of motion for times as long as $10^9$, our probability distribution functions always tend to Gaussians and show that the dynamics does not relax onto a quasi-periodic KAM torus and that diffusion continues to spread chaotically for arbitrarily long times.
description: 16 pages, 4 figures, accepted for publication in "Chaos: An Interdisciplinary Journal of Nonlinear Science" journal
The Chiral index of the fermionic signature operator
Creators: name: Finster, Felix
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: 510 Mathematik

description: We define an index of the fermionic signature operator on even-dimensional globally hyperbolic spin manifolds of finite lifetime. The invariance of the index under homotopies is studied. The definition is generalized to causal fermion systems with a chiral grading. We give examples of space-times and Dirac operators thereon for which our index is non-trivial.
New equidistribution estimates of Zhang type
Creators: name: Polymath, D. H. J.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11P32

description: We prove distribution estimates for primes in arithmetic progressions to large smooth squarefree moduli, with respect to congruence classes obeying Chinese Remainder Theorem conditions, obtaining an exponent of distribution $\frac{1}{2} + \frac{7}{300}$.
description: 107 pages, no figures. This is the revised version, focusing solely on equidistribution estimates
Jean Leclercq Ein Humanist wird Eremit. Paul Giustiniani (1476–1528). Aus dem Französischen übersetzt und bearbeitet von Plazidus-Karl Hungerbühler, Aachen: Patrimonium 2019 und Jean Leclercq, Mit Gott allein. Das eremitische Leben nach der Lehre des Se
Creators: name: Thurner, Martin
Publisher: name: Münchener Theologische Zeitschrift
Year: 2023

description: Münchener Theologische Zeitschrift, Bd. 72 Nr. 3 (2021)
Numerical approximation of phase field based shape and topology optimization for fluids
Creators: name: Garcke, Harald
name: Hecht, Claudia
name: Hinze, Michael
name: Kahle, Christian
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: Shape optimization, topology optimization, diffuse interfaces, Cahn-Hilliard, Navier-Stokes, adaptive meshing
subject: 510 Mathematik
subject: 35Q35
subject: 35Q56
subject: 35R35
subject: 49Q10
subject: 65M12
subject: 65M22
subject: 65M60
subject: 76S05

description: We consider the problem of finding optimal shapes of fluid domains. The fluid obeys the Navier{Stokes equations. Inside a holdall container we use a phase field approach using diffuse interfaces to describe the domain of free flow. We formulate a corresponding optimization problem where flow outside the fluid domain is penalized. The resulting formulation of the shape optimization problem is shown to be well-posed, hence there exists a minimizer, and first order optimality conditions are derived. For the numerical realization we introduce a mass conserving gradient flow and obtain a Cahn{Hilliard type system, which is integrated numerically using the finite element method. An adaptive concept using reliable, residual based error estimation is exploited for the resolution of the spatial mesh. The overall concept is numerically investigated and comparison values are provided.
Proposal to search for a dark photon in $e^+$ on target collisions at DA$Φ$NE linac
Creators: name: Raggi, Mauro
name: Kozhuharov, Venelin
Publisher: name: arXiv
Year: 2014
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Photon-like particles are predicted in many extensions of the Standard Model. They have interactions similar to the photon, are vector bosons, and can be produced together with photons. The present paper proposes a search for such particles in the $ e^+e^- \to Uγ$ process in a positron-on-target experiment, exploiting the positron beam of the DA$Φ$NE linac at the Laboratori Nazionali di Frascati, INFN. In one year of running a sensitivity in the relative interaction strength down to $\sim10^{-6}$ is achievable, in the mass region from 2.5 MeV$
description: 19 pages, 21 figures, version accepted for publication in Adv. in HEP
Felix Krause, Sozial verantwortete Selbstbestimmung in der Medizin. Ein anerkennungstheoretischer Ansatz selbstbestimmten Handelns, Frankfurt a. M. u. a.: Peter Lang 2016
Creators: name: Ebner, Katharina
Publisher: name: Münchener Theologische Zeitschrift
Year: 2023

description: Münchener Theologische Zeitschrift, Bd. 72 Nr. 3 (2021)
Applications of Social Exchange, Human Capital and Dynamic Capability Theories in Management Studies: A Review
Creators: name: Tilahun, Tesfaye
Publisher: name: Journal of Business and Administrative Studies
Year: 2022

description: The purpose of this theoretical article is to give insight into the application of social exchange theory, human capital theory, and dynamic capability theory in the discipline of management. The prepositions, purpose, advantages, and critics related to each management-related theory were addressed. The theoretical review result indicated that social exchange theory can contribute more to boosting the productivity level of an organization and the satisfaction level of the employees. However, in the process of socialization, information security and disclosure-related issues have to be strictly followed and methods of supervision are in place. On the other hand, human beings need attention and focus from their respective managers. The focus of managers on the human capital that they have can be determined as capital investment. So, human capital investment can boost the performance of employees and the overall productivity of the organization. Individuals who are assigned in business areas have to know that the current highly competitive working environment needs compatible and situational employees and contemporary management style and approach. In this context, dynamic capability theory plays a significant contribution to the modern highly competitive business environment. Therefore, to win the current competitive market and to increase both the satisfaction level of the customer and the employees, managers have to know the basic concepts and applications of social exchange theory, human capital theory, and dynamic capability theory as a mere factor of success.
description: Journal of Business and Administrative Studies, Vol. 13 No. 1 (2021): Journal of Business and Administrative Studies
A spectral unaveraged algorithm for free electron laser simulations
Creators: name: Andriyash, Igor A.
name: Lehe, Remi
name: Malka, Victor
Publisher: name: arXiv
Year: 2014
Subjects: subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We propose and discuss a numerical method to model electromagnetic emission from the oscillating relativistic charged particles and its coherent amplification. The developed technique is well suited for free electron laser simulations, but it may also be useful for a wider range of physical problems involving resonant field-particles interactions. The algorithm integrates the unaveraged coupled equations for the particles and the electromagnetic fields in a discrete spectral domain. Using this algorithm, it is possible to perform full three-dimensional or axisymmetric simulations of short-wavelength amplification. In this paper we describe the method, its implementation, and we present examples of free electron laser simulations comparing the results with the ones provided by commonly known free electron laser codes.
description: submitted to J. Comp. Phys
Radiative observables for linearized gravity on asymptotically flat spacetimes and their boundary induced states
Creators: name: Bennini, Marco
name: Dappiaggi, Claudio
name: Murro, Simone
Publisher: name: Universität Regensburg
Year: 2014
Subjects: subject: quantum field theory on curved spacetimes, Hadamard states, linearized gravity
subject: 510 Mathematik
subject: 81T20
subject: 81T05

description: We discuss the quantization of linearized gravity on globally hyperbolic, asymptotically flat, vacuum spacetimes and the construction of distinguished states which are both of Hadamard form and invariant under the action of all bulk isometries. The procedure, we follow, consists of looking for a realization of the observables of the theory as a sub-algebra of an auxiliary, non-dynamical algebra constructed on future null infinity ℑ+. The applicability of this scheme is tantamount to proving that a solution of the equations of motion for linearized gravity can be extended smoothly to ℑ+. This has been claimed to be possible provided that a suitable gauge fixing condition, first written by Geroch and Xanthopoulos, is imposed. We review its definition critically showing that there exists a previously unnoticed obstruction in its implementation leading us to introducing the concept of radiative observables. These constitute an algebra for which a Hadamard state induced from null infinity and invariant under the action of all spacetime isometries exists and it is explicitly constructed.
Determinant of Micro Enterprise Growth in the Manufacturing Sector: The case of Jimma Town
Creators: name: Tadesse Firisa, Tomas
Publisher: name: Journal of Business and Administrative Studies
Year: 2022

description: The main aim of the study was to examine factors affecting the growth of microenterprises in the manufacturing sector in Jimma town. To this end, the study used descriptive and explanatory research design and data was conducted from 186 respondents. The study found out the effect of working premises, managerial, infrastructure, and financial factors on the growth of micro-enterprises in manufacturing operating in Jimma town, the correlation analysis shows the relationship between working premises, managerial, infrastructure and financial factors and growth of micro-enterprises in manufacturing sector were strong and positive relationship and the results of regression analysis observed that working premises, managerial, infrastructure and financial factors have a significant positive effect on the performance of micro-enterprises in manufacturing sector, the researcher recommends that the government needs to establish training centers for training managerial and technical courses for the micro-enterprises entrepreneurs as well as business information centers and to develop a comfortable source of finance for micro-enterprise, the government should have to organize and support the performance of Micro Finance Institutions and another source of finance and Jimma town micro-enterprise and food security office be supposed to undertake a detailed study on the appropriateness of the working place to be given to each type of enterprises.
description: Journal of Business and Administrative Studies, Vol. 13 No. 1 (2021): Journal of Business and Administrative Studies
The fermionic signature operator and quantum states in Rindler space-time
Creators: name: Finster, Felix
name: Murro, Simone
name: Röken, Christian
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: 510 Mathematik

description: The fermionic signature operator is constructed in Rindler space-time. It is shown to be an unbounded self-adjoint operator on the Hilbert space of solutions of the massive Dirac equation. In two-dimensional Rindler space-time, we prove that the resulting fermionic projector state coincides with the Fulling-Rindler vacuum. Moreover, the fermionic signature operator gives a covariant construction of general thermal states, in particular of the Unruh state. The fermionic signature operator is shown to be well-defined in asymptotically Rindler space-times. In four-dimensional Rindler space-time, our construction gives rise to new quantum states.
Stable variational approximations of boundary value problems for Willmore flow with Gaussian curvature
Creators: name: Barrett, John W.
name: Garcke, Harald
name: Nürnberg, Robert
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: Willmore flow, parametric finite elements, tangential movement, spontaneous curvature, clamped boundary conditions, Navier boundary conditions, Gaussian curvature energy, line energy
subject: 510 Mathematik
subject: 65M60
subject: 65M12
subject: 35K55
subject: 53C44

description: We study numerical approximations for geometric evolution equations arising as gradient flows for energy functionals that are quadratic in the principal curvatures of a two-dimensional surface. Beside the well-known Willmore and Helfrich flows we will also consider flows involving the Gaussian curvature of the surface. Boundary conditions for these flows are highly nonlinear, and we use a variational approach to derive weak formulations, which naturally can be discretized with the help of a mixed finite element method. Our approach uses a parametric finite element method, which can be shown to lead to good mesh properties. We prove stability estimates for a semidiscrete (discrete in space, continuous in time) version of the method and show existence and uniqueness results in the fully discrete case. Finally, several numerical results are presented involving convergence tests as well as the first computations with Gaussian curvature and/or free or semi-free boundary conditions.
An integral representation for the massive Dirac propagator in Kerr geometry in Eddington-Finkelstein-type coordinates
Creators: name: Finster, Felix
name: Röken, Christian
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: 510 Mathematik

description: The massive Dirac equation is considered in the non-extreme Kerr geometry in horizon-penetrating Eddington-Finkelstein-type coordinates. We derive an integral representation for the Dirac propagator involving the solutions of the ODEs which arise in Chandrasekhar's separation of variables. This integral representation describes the dynamics of Dirac waves outside and across the event horizon, up to the Cauchy horizon. For the proof, we write the Dirac equation in Hamiltonian form. One of the main di�culties is that the time evolution is not unitary, because the wave may \hit" the singularity. This problem is resolved by imposing suitable Dirichlet-type boundary conditions inside the Cauchy horizon, having no effect on the outside dynamics. Another main difficulty is that the Dirac Hamiltonian fails to be elliptic at the horizons. Combining the theory of symmetric hyperbolic systems with elliptic methods near the boundary, we construct a self-adjoint extension of the resulting Hamiltonian. We finally apply Stone's formula to the spectral measure of the Hamiltonian and express the resolvent in terms of solutions of the separated ODEs.
Der M&A Canvas zur Analyse der strategischen Passung von Akquisitions- und Kooperationskandidaten
Creators: name: Schmalfuß, Martin
name: Hofstetter, Christine
name: Helm, Roland
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: 330 Wirtschaft

description: Im strategischen Management ist externes Unternehmenswachstum durch die Übernahme von Unternehmen zur Erreichung definierter unternehmerischer Zielsetzungen eine Option. Ein wichtiges Kriterium bei der Bewertung eines Akquisitionskandidaten im Rahmen der Pre-Acquisition Phase ist die strategische Passung. In der Literatur findet sich dazu eine Reihe an Analyseinstrumenten. Einige dieser Methoden scheitern schlichtweg an Praxisfähigkeit, andere helfen auf Grund der nicht gegebenen, aber dringend gebotenen Ganzheitlichkeit, nur bedingt weiter. Mit dem M&A Canvas soll eine Methode vorgestellt werden, die den Prozess der Bewertung des strategischen Fits in wenigen, einfach nachvollziehbaren Schritten ermöglicht. Ausgehend von einem Vergleich des eigenen Geschäftsmodells mit dem des Übernahmekandidaten werden dabei potentielle Synergien, wie auch Dyssynergien identifiziert, kurz beschrieben und bewertet. Im Weiteren erfolgen die Quantifizierung der (Dys)synergien und eine Bewertung der Eintrittswahrscheinlichkeiten. Die in diesen einfachen Arbeitsschritten erarbeiteten Ergebnisse lassen sich nun aufwandsarm in eine erste, rudimentäre Bewertung überführen und geben ein sowohl qualitativ, als auch quantitativ beschriebenes und auf den Punkt gebrachtes Bild der strategischen Passung zwischen dem akquirierenden Unternehmen und dem potentiellen Kaufkandidaten. Der M&A Canvas hat seine Praxistauglichkeit bereits erfolgreich unter Beweis stellen können und lässt sich unabhängig von Branche und Unternehmensgröße anwenden. Die Erfahrung zeigt, dass Strategic Fit Bewertungen bei Anwendung der Methode äußerst effizient und zielgerichtet verlaufen und die Ergebnisse bereits in dieser Phase wertvolle Informationen für die spätere kaufmännische Bewertung liefern.
Risk Management in Building Construction Projects: Contractors and Consultants Perspectives
Creators: name: Teferi, Alem
name: Bekana, Dejene Mamo
Publisher: name: Journal of Business and Administrative Studies
Year: 2022

description: This investigation aims at identifying the major risk factors that contribute to the possible occurrence of risk on building construction projects in Addis Ababa. Participants of the study, located in Addis Ababa, were grade one contractors and consultants. To achieve its objective, a mixed method research design approach was deployed in this study. It also implemented descriptive research design for the purpose of describing situations and facts to the research questions. Questionnaire survey was conducted for collecting data from a simple random sample of 100 people. The collected data was analyzed through Statistical Package for Social Science / IBM SPSS 24/ and the results are presented through statistical tools such as frequency tables, graphs, and charts, etc. The research findings indicated that 5 critical risk factors were identified based on an assessment of their probability of occurrence on building construction projects. These were “high inflation rate”, “delayed payment by client”, “poor resource management”, “risk of corruption”, and “economic instability” that have influence on project objectives. Financial factor was the most significant risk category recognized by participants. Hence, the two most critical possible risks identified were time overrun and cost overrun. It was also indicated that for effective risk alleviation risk transfer and reduction measures were the major strategies recognized by participants. Further investigation of opinions from the study revealed that there was lack of knowledge of risk management which needs to be improved. It was concluded that consultants and contractors as well as other stakeholders need to work in tandem to improve the environment of risk management in building construction industry.
description: Journal of Business and Administrative Studies, Vol. 13 No. 1 (2021): Journal of Business and Administrative Studies
Revisiting Farrell's nonfiniteness of Nil
Creators: name: Lafont, Jean-François
name: Prassidis, Stratos
name: Wang, Kun
Publisher: name: arXiv
Year: 2014
Subjects: subject: K-Theory and Homology (math.KT)
subject: Geometric Topology (math.GT)
subject: FOS: Mathematics

description: We study Farrell Nil-groups associated to a finite order automorphism of a ring $R$. We show that any such Farrell Nil-group is either trivial, or infinitely generated (as an abelian group). Building on this first result, we then show that any finite group that occurs in such a Farrell Nil-group occurs with infinite multiplicity. If the original finite group is a direct summand, then the countably infinite sum of the finite subgroup also appears as a direct summand. We use this to deduce a structure theorem for countable Farrell Nil-groups with finite exponent. Finally, as an application, we show that if $V$ is any virtually cyclic group, then the associated Farrell or Waldhausen Nil-groups can always be expressed as a countably infinite sum of copies of a finite group, provided they have finite exponent (which is always the case in dimension $0$).
description: add some remarks, references, 17 pages
Detecting relic gravitational waves in the CMB: The contamination caused by the cosmological birefringence
Creators: name: Zhao, Wen
name: Li, Mingzhe
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: The B-mode polarization of the cosmic microwave background (CMB) radiation is an excellent information channel for the detection of relic gravitational waves. However, the detection is contaminated by the B-mode polarization generated by some other effects. In this paper, we discuss the contaminations caused by the cosmological birefringence, which converts the CMB E-mode to the B-mode, and forms the effective noise for the detection of gravitational waves. We find that this contamination is significant, if the rotation angle is large. However, this kind of B-mode can be properly de-rotated, and the effective noises can be greatly reduced. We find that, comparing with the contaminations caused by cosmic weak lensing, the residual polarization generated by the cosmological birefringence is negligible for the detection of relic gravitational waves in the CMB.
description: 9 pages, 4 figures, references added, PLB accepted
Higgs sector in NMSSM with right-handed neutrinos and spontaneous R-parity violation
Creators: name: Huitu, Katri
name: Waltari, Harri
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: R-parity violation modifies the phenomenology of supersymmetric models considerably. We study a version of NMSSM, which contains right-handed neutrinos and in which spontaneous R-parity violation is possible. We study the ensuing effects of spontaneous breaking to the Higgs decay modes, taking into account the measured mass of the Higgs boson and experimental constraints, including rare decays. We find that a possible light scalar, dominantly a sneutrino, helps to increase the Standard Model (SM) Higgs-like scalar mass to the measured value. At the same time, a lighter stop than in the MSSM is allowed. The Higgs decay rates in the studied model can somewhat differ from the SM expectations, although the most prominent difference is a universal suppression in the couplings due to the mixing of doublet scalars with singlets. The charged, pseudoscalar, and other than the two lightest scalar Higgses are typically heavier than 1 TeV in the parameter region where R-parity is spontaneously broken.
description: Revised version, 32 pages, 11 figures
Dynamical gravitational coupling as a modified theory of general relativity
Creators: name: Finster, Felix
name: Röken, Christian
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: 510 Mathematik

description: A modified theory of general relativity is proposed, where the gravitational constant is replaced by a dynamical variable in space-time. The dynamics of the gravitational coupling is described by a family of parametrized null geodesics, implying that the gravitational coupling at a space-time point is determined by solving transport equations along all null geodesics through this point. General relativity with dynamical gravitational coupling (DGC) is introduced. We motivate DGC from general considerations and explain how it arises in the context of causal fermion systems. The underlying physical idea is that the gravitational coupling is determined by microscopic structures on the Planck scale which propagate with the speed of light. In order to clarify the mathematical structure, we analyze the conformal behavior and prove local existence and uniqueness of the time evolution. The differences to Einstein's theory are worked out in the examples of the Friedmann-Robertson- Walker model and the spherically symmetric collapse of a shell of matter. Potential implications for the problem of dark matter and for inflation are discussed. It is shown that the effects in the solar system are too small for being observable in present-day experiments.
Evaluation of the neutron background in CsI target for WIMP direct detection when using a reactor neutrino detector as a neutron veto system
Creators: name: Xu, Ye
name: Ji, Xiangpan
name: Li, Haolin
name: Feng, Yulong
Publisher: name: arXiv
Year: 2013
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: A direct WIMP (Weakly Interacting Massive Particle) detector with a neutron veto system is designed to better reject neutrons. An experimental configuration is studied in the present paper: a WIMP detectors with CsI(Na) target is placed inside a reactor neutrino detector. The neutrino detector is used as a neutron veto device. The neutron background for the experimental design has been estimated using the Geant4 simulation. The results show that the neutron background can decrease to O(0.01) events per year per tonne of CsI(Na). We calculate the sensitivity to spin-independent WIMP-nucleon elastic scattering. An exposure of one tonne $\times$ year could reach a cross-section of about 3$\times$$10^{-11}$ pb.
description: 10 pages, 3 figures. arXiv admin note: substantial text overlap with arXiv:1205.0428, arXiv:1008.0145
A Systematic Review of Clinical Success of Ceramic Implants
Creators: name: Alamanos, Christos
name: Knüttel, Helge
name: Behr, Michael
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: ceramic implants, biological complications, osseointegration, survival rates, success rates
subject: 610 Medizin

description: Objectives: The objective of this systematic review was to assess the published data concerning the short-term and midterm survival and success rates of ceramic dental implants (alumina, yttria-stabilized tetragonal zirconia polycrystals) and to describe the incidence of biological complications (implant loss, peri-implant disease). Methods: An electronic search was conducted to identify prospective cohort and retrospective clinical studies, case series, as well as previous reviews on ceramic implants with a mean follow-up time of at least one year. The search was performed in the following databases: Medline, Cochrane Library, Biosis, Embase and Web of Science. Furthermore, the reference lists of related review articles selected for inclusion in this review were screened. The last search was conducted in January 2016. All studies were first reviewed by abstract and subsequently by full-text by two examiners independently. Results: The electronic search yielded 1022 publications and 223 abstracts. Full-text analysis was performed for 50 articles resulting in a total of 36 clinical studies that fulfilled the inclusion criteria. Clinical studies using alumina dental implants showed survival/success rates in the range of 23% to 98%. The survival rates for zirconia implants range from 74-100% after 12-60 months, with success rates between 79.6-91.6% 6-12 months after functional loading. Conclusions: Alumina implants do not perform satisfactorily and therefore it can be concluded that they should not be considered an alternative to titanium. Concerning the zirconia implants, the evidence available to date indicates that they are inferior to titanium implants with regard to survival and success rates. Zirconia implants with roughened surfaces though, might be a viable solution. More longitudinal clinical studies are necessary to substantiate the longterm clinical efficacy of zirconia in implant dentistry.
Enhancement of chaotic subdiffusion in disordered ladders with synthetic gauge fields
Creators: name: Yu, Xiaoquan
name: Flach, Sergej
Publisher: name: arXiv
Year: 2014
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Quantum Gases (cond-mat.quant-gas)
subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: We study spreading wave packets in a disordered nonlinear ladder with broken time-reversal symmetry induced by synthetic gauge fields. The model describes the dynamics of interacting bosons in a disordered and driven optical ladder within a mean-field approximation. The second moment of the wave packet $m_{2} = g t^α$ grows subdiffusively with the universal exponent $α\simeq 1/3$ similar to the time-reversal case. However the prefactor $g$ is strongly modified by the field strength and shows a non-monotonic dependence. For a weak field, the prefactor increases since time-reversal enhanced backscattering is suppressed. For strong fields the spectrum of the linear wave equation reduces the localization length through the formation of gaps and narrow bands. Consequently the prefactor for the subdiffusive spreading law is suppressed.
description: 7 pages, 12 figures, Figs. 6, 7 and 8 added, references added, typos corrected
title: There’s More to it Than Just “Good Job!” – The 7 Principles of Good Feedback
Creators: name: Rottmeier, Stephanie
Publisher: name: Zentrum für Hochschul- und Wissenschaftsdidaktik, Universität Regensburg
Year: 2021

description: To give good feedback is a core competence of instructors. This blog post introduces 7 tips on how to give good feedback.
An operatorial approach to stochastic partial differential equations driven by linear multiplicative noise
Creators: name: Barbu, Viorel
name: Röckner, Michael
Publisher: name: arXiv
Year: 2014
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: In this paper, we develop a new general approach to the existence and uniqueness theory of infinite dimensional stochastic equations of the form dX+A(t)Xdt = XdW in (0;T)xH, where A(t) is a nonlinear monotone and demicontinuous operator from V to V', coercive and with polynomial growth. Here, V is a reflexive Banach space continuously and densely embedded in a Hilbert space H of (generalized) functions on a domain $O\subset \mathbb{R}^d$ and V' is the dual of V in the duality induced by H as pivot space. Furthermore, W is a Wiener process in H. The new approach is based on an operatorial reformulation of the stochastic equation which is quite robust under perturbation of A(t). This leads to new existence and uniqueness results of a larger class of equations with linear multiplicative noise than the one treatable by the known approaches. In addition, we obtain regularity results for the solutions with respect to both the time and spatial variable which are sharper than the classical ones. New applications include stochastic partial differential equations, as e.g. stochastic transport equations.
سن الرشد الرقمي - دراسة مقارنة في القوانين المصري والأوروبي والفرنسي
Creators: name: Eldomiaty, Dr. Tamer
Publisher: name: figshare
Year: 2023
Subjects: Property law (excl. intellectual property law)
Private law and civil obligations not elsewhere classified
Law, science and technology
Legal theory, jurisprudence and legal interpretation
Media and communication law

description: law law Data protection
Resource approximation for the $λμ$-calculus
Creators: name: Barbarossa, Davide
Publisher: name: arXiv
Year: 2024
Subjects: subject: Logic in Computer Science (cs.LO)
subject: FOS: Computer and information sciences

description: The $λμ$-calculus plays a central role in the theory of programming languages as it extends the Curry-Howard correspondence to classical logic. A major drawback is that it does not satisfy Böhm's Theorem and it lacks the corresponding notion of approximation. On the contrary, we show that Ehrhard and Regnier's Taylor expansion can be easily adapted, thus providing a resource conscious approximation theory. This produces a sensible $λμ$-theory with which we prove some advanced properties of the $λμ$-calculus, such as Stability and Perpendicular Lines Property, from which the impossibility of parallel computations follows.
Decision Support for IT Investment Projects
Creators: name: Müller, Marcel Philipp
name: Stöckl, Sebastian
name: Zimmermann, Steffen
name: Heinrich, Bernd
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: INFORMATION-TECHNOLOGY INVESTMENTS; OPTION-PRICING THEORY; REAL OPTIONS; MEAN REVERSION; COMMODITY PRICES; DESIGN SCIENCE; BUSINESS VALUE; VALUATION; RISK; UNCERTAINTY; Real option analysis; Business value of IT investment projects; Simulation model; Black-Scholes model; IT investment project decisions; Assumptions; Characteristics of IT investment projects
subject: 330 Wirtschaft
subject: 650 Management

description: Managerial flexibilities have to be taken into account in ex-ante decision-making on IT investment projects (ITIPs). In many papers of the IS literature, standard financial option pricing models are used to value such managerial flexibilities. Based on a review of the related literature, the paper critically discusses the assumptions of the most frequently used financial option pricing model, namely the Black-Scholes model, arguing for relaxed assumptions that better represent the characteristics of ITIPs. The authors find that existing real option analysis approaches featured in the IS, Finance, and Economics literature are unable to consider more than two of our relaxed assumptions. Consequently, they present their own approach in form of a simulation model for the valuation of real options in ITIPs which offers a better representation of the characteristics of ITIPs by taking the discounted cash-flows and the runtime to be uncertain as well as the market to be incomplete. Based on these modifications of the Black-Scholes model's assumptions, it is found that the resulting option value contains idiosyncratic risk that has to be taken into account in ITIP decision making. For the realistic case of risk averse decision makers, the consideration of idiosyncratic risk usually leads to a lower risk-adjusted option value, compared to one calculated by means of the Black-Scholes model. This confirms the perception of managers who feel that financial option pricing models frequently overvalue ITIPs and hence may induce flawed investment decisions.
Potential Vorticity in Magnetohydrodynamics
Creators: name: Webb, G. M.
name: Mace, R. L.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: A version of Noether's second theorem using Lagrange multipliers is used to investigate fluid relabelling symmetries conservation laws in magnetohydrodynamics (MHD). We obtain a new generalized potential vorticity type conservation equation for MHD which takes into account entropy gradients and the ${\bf J}\times{\bf B}$ force on the plasma due to the current ${\bf J}$ and magnetic induction ${\bf B}$. This new conservation law for MHD is derived by using Noether's second theorem in conjunction with a class of fluid relabelling symmetries in which the symmetry generator for the Lagrange label transformations is non-parallel to the magnetic field induction in Lagrange label space. This is associated with an Abelian Lie pseudo algebra and a foliated phase space in Lagrange label space. It contains as a special case Ertel's theorem in ideal fluid mechanics. An independent derivation shows that the new conservation law is also valid for more general physical situations.
description: 0 figures
ProSLM : A Prolog Synergized Language Model for explainable Domain Specific Knowledge Based Question Answering
Creators: name: Vakharia, Priyesh
name: Kufeldt, Abigail
name: Meyers, Max
name: Lane, Ian
name: Gilpin, Leilani
Publisher: name: arXiv
Year: 2024
Subjects: subject: Computation and Language (cs.CL)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences
subject: I.2

description: Neurosymbolic approaches can add robustness to opaque neural systems by incorporating explainable symbolic representations. However, previous approaches have not used formal logic to contextualize queries to and validate outputs of large language models (LLMs). We propose \systemname{}, a novel neurosymbolic framework, to improve the robustness and reliability of LLMs in question-answering tasks. We provide \systemname{} with a domain-specific knowledge base, a logical reasoning system, and an integration to an existing LLM. This framework has two capabilities (1) context gathering: generating explainable and relevant context for a given query, and (2) validation: confirming and validating the factual accuracy of a statement in accordance with a knowledge base (KB). Our work opens a new area of neurosymbolic generative AI text validation and user personalization.
description: Accepted at NeSy 2024
Moorea Biocode Access and Benefit Sharing Agreement
Creators: name: Davies, Neil
name: Hirsch, Leonard P.
Publisher: name: Zenodo
Year: 2010
Subjects: Biodiversity
ABS

description: The document was drawn up as part of the Moorea Biocode Project after broad consultation with academic and government partners and participation in the Convention on Biological Diversity (CBD) Ad Hoc Open-ended Working Group on Access and Benefit-sharing. When the Moorea Biocode Project was launched, the Convention on Biological Diversity’s (CBD) ABS protocol was not yet formalized and the Bonn Guidelines served as a framework for those wishing to conform to the “spirit of the CBD”. Despite the absence of a legal framework for ABS, Moorea Biocode Project developed with French Polynesia this document as a model (or template) for similar studies and to assist French Polynesia and other authorities in considering their future policy options.
Modelling and analysis of turbulent datasets using ARMA processes
Creators: name: Faranda, Davide
name: Pons, Flavio Maria Emanuele
name: Dubrulle, Bérèngere
name: Daviaud, François
name: Saint-Michel, Brice
name: Herbert, Éric
name: Cortet, Pierre-Philippe
Publisher: name: arXiv
Year: 2014
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We introduce a novel way to extract information from turbulent datasets by applying an ARMA statistical analysis. Such analysis goes well beyond the analysis of the mean flow and of the fluctuations and links the behavior of the recorded time series to a discrete version of a stochastic differential equation which is able to describe the correlation structure in the dataset. We introduce a new intermittency parameter $Υ$ that measures the difference between the resulting analysis and the Obukhov model of turbulence, the simplest stochastic model reproducing both Richardson law and the Kolmogorov spectrum. We test the method on datasets measured in a von Kármán swirling flow experiment. We found that the ARMA analysis is well correlated with spatial structures of the flow, and can discriminate between two different flows with comparable mean velocities, obtained by changing the forcing. Moreover, we show that the intermittency parameter is highest in regions where shear layer vortices are present, thereby establishing a link between intermittency corrections and coherent structures. We show that some salient features of the analysis are preserved when considering global instead of local observables. Finally we analyze flow configurations with multistability features where the ARMA technique is efficient in discriminating different stability branches of the system.
description: 33 pages, 8 figures