cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Asymptotics in directed exponential random graph models with an increasing bi-degree sequence
Creators: name: Yan, Ting
name: Leng, Chenlei
name: Zhu, Ji
Publisher: name: arXiv
Year: 2014
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics

description: Although asymptotic analyses of undirected network models based on degree sequences have started to appear in recent literature, it remains an open problem to study statistical properties of directed network models. In this paper, we provide for the first time a rigorous analysis of directed exponential random graph models using the in-degrees and out-degrees as sufficient statistics with binary as well as continuous weighted edges. We establish the uniform consistency and the asymptotic normality for the maximum likelihood estimate, when the number of parameters grows and only one realized observation of the graph is available. One key technique in the proofs is to approximate the inverse of the Fisher information matrix using a simple matrix with high accuracy. Numerical studies confirm our theoretical findings.
description: Published at http://dx.doi.org/10.1214/15-AOS1343 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org)
A New Approach to Cosmological Bulk Viscosity
Creators: name: Disconzi, Marcelo M.
name: Kephart, Thomas W.
name: Scherrer, Robert J.
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We examine the cosmological consequences of an alternative to the standard expression for bulk viscosity, one which was proposed to avoid the propagation of superluminal signals without the necessity of extending the space of variables of the theory. The Friedmann equation is derived for this case, along with an expression for the effective pressure. We find solutions for the evolution of the density of a viscous component, which differs markedly from the case of conventional Eckart theory; our model evolves toward late-time phantom-like behavior with a future singularity. Entropy production is addressed, and some similarities and differences to approaches based on the Mueller-Israel-Stewart theory are discussed.
description: Text and references expanded. To appear in Physical Review D
Graviton-Photon Scattering
Creators: name: Bjerrum-Bohr, N. E. J.
name: Holstein, Barry R.
name: Planté, Ludovic
name: Vanhove, Pierre
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We use the feature that the gravitational Compton scattering amplitude factorizes in terms of Abelian QED amplitudes to evaluate various gravitational Compton processes. We examine both the QED and gravitational Compton scattering from a massive spin-1 system by the use of helicity amplitude methods. In the case of gravitational Compton scattering we show how the massless limit can be used to evaluate the cross section for graviton-photon scattering and discuss the difference between photon interactions and the zero mass spin-1 limit. We show that the forward scattering cross section for graviton photoproduction has a very peculiar behavior, differing from the standard Thomson and Rutherford cross sections for a Coulomb-like potential.
description: LaTeX, 33 pages, 5 figures; v2 typos corrected, version to be published in PRD
Supplementary file 2 from Differential proteome profiling of bacterial culture supernatants reveals candidates for the induction of oral immune priming in the Red Flour Beetle
Creators: name: Länger, Zoe Marie
name: Baur, Moritz
name: Korša, Ana
name: Eirich, Jürgen
name: Lindeza, Ana Sofia
name: Zanchi, Caroline
name: Finkemeier, Iris
name: Kurtz, Joachim
Publisher: name: The Royal Society
Year: 2023
Subjects: classificationCode: 310499
subject: Evolutionary biology not elsewhere classified

description: Survival data, R scripts and statistics
Coupled Ostrovsky equations for internal waves in a shear flow
Creators: name: Alias, A.
name: Grimshaw, R. H. J.
name: Khusnutdinova, K. R.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: In the context of fluid flows, the coupled Ostrovsky equations arise when two distinct linear long wave modes have nearly coincident phase speeds in the presence of background rotation. In this paper, nonlinear waves in a stratified fluid in the presence of shear flow are investigated both analytically, using techniques from asymptotic perturbation theory, and through numerical simulations. The dispersion relation of the system, based on a three-layer model of a stratified shear flow, reveals various dynamical behaviours, including the existence of unsteady and steady envelope wave packets.
description: 47 pages, 39 figures, accepted to Physics of Fluids
Supplementary files from Differential proteome profiling of bacterial culture supernatants reveals candidates for the induction of oral immune priming in the Red Flour Beetle
Creators: name: Länger, Zoe Marie
name: Baur, Moritz
name: Korša, Ana
name: Eirich, Jürgen
name: Lindeza, Ana Sofia
name: Zanchi, Caroline
name: Finkemeier, Iris
name: Kurtz, Joachim
Publisher: name: The Royal Society
Year: 2023
Subjects: classificationCode: 310499
subject: Evolutionary biology not elsewhere classified

description: Most organisms are host to symbionts and pathogens, which led to the evolution of immune strategies to prevent harm. Whilst the immune defences of vertebrates are classically divided into innate and adaptive, insects lack specialized cells involved in adaptive immunity, but have been shown to exhibit immune priming: the enhanced survival upon infection after a first exposure to the same pathogen or pathogen-derived components. An important piece of the puzzle are the pathogen-associated molecules that induce these immune priming responses. Here, we make use of the model system consisting of the red flour beetle (Tribolium castaneum) and its bacterial pathogen Bacillus thuringiensis, to compare the proteomes of culture supernatants of two closely related B. thuringiensis strains that either induce priming via the oral route, or not. Among the proteins that might be immunostimulatory to T. castaneum, we identify the Cry3Aa toxin, an important plasmid-encoded virulence factor of B. thuringiensis. In further priming-infection assays we test the relevance of Cry-carrying plasmids for immune priming. Our findings provide valuable insights for future studies to perform experiments on the mechanisms and evolution of immune priming.
title: Berufskrankheit Burnout
Creators: name: Henzl, Sarah
Year: 2021

description: Hintergrund: Lehrer*innen sind eine häufig von Burnout betroffenen Berufsgruppe, besonders während der COVID-19-Pandemie erlebte das Lehrpersonal zusätzliche Belastungen. Forschungen zu Lehrpersonal und anderen Berufsgruppen konnten Zusammenhänge zwischen Burnout und den Variablen Geschlecht, Alter und Beziehungsstatus sowie bevorzugten Bewältigungsstrategien feststellen. Die Studienergebnisse waren sich jedoch uneins, ob und in welche Richtung diese Zusammenhänge bestehen. Methodik: Im Rahmen dieser Masterarbeitsstudie wurden 329 Wiener Lehrer*innen in einer Querschnittstudie mittels selbstzusammengestellter Online-Fragebogenbatterie hinsichtlich Geschlechts-, Alters-, Beziehungsstatus- und Bewältigungsstrategieunterschieden in Burnout untersucht. Burnout wurde dafür mithilfe der Fragebögen Maslach Burnout Inventory und Burnout-Screening-Skalen I erhoben, die anschließend miteinander verglichen wurden. Weiters wurden Copingstrategien und wahrgenommener Stress mittels des Coping Inventory for Stressful Situations und der deutschen Kurzform der Perceived Stress Scale erfasst. Ergebnisse: Die statistische Auswertung ergab geringe Geschlechts-, Alters- und Beziehungsstatusunterschiede für einzelne Subskalen und Gesamtwerte des MBI, jedoch keine Unterschiede hinsichtlich der Bereiche, die mittels BOSS I erfasst wurden. Lehrpersonal, das vermehrt aufgabenorientiert bewältigt, wies in allen Skalen und Gesamtwerten des MBI und BOSS I geringere Burnoutwerte auf als Lehrer*innen, die emotionsorientiertes Coping bevorzugten. Die Unterschiede in der Dimension Depersonalisation bestanden auch bei Konstanthaltung der Störvariable Geschlecht. Interne Konsistenzen, Flächen unter ROC-Kurven und relative Validität betrachtend ist die BOSS I geeigneter, den Stressaspekt von Burnout bei Wiener Lehrer*innen zu erfassen. Schlussfolgerung: Diese Ergebnisse deuten darauf hin, dass in zukünftiger Forschung soziodemographische Unterschiede bei Lehrer*innen noch einmal untersucht werden sollten, diesmal und in Zukunft aber vermehrt alternative Verfahren zum MBI eingesetzt werden sollten.
$\mathbb{Z}_2$ invariants of topological insulators as geometric obstructions
Creators: name: Fiorenza, Domenico
name: Monaco, Domenico
name: Panati, Gianluca
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mathematical Physics (math-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences
subject: 81Q70, 35J10

description: We consider a gapped periodic quantum system with time-reversal symmetry of fermionic (or odd) type, i.e. the time-reversal operator squares to -1. We investigate the existence of periodic and time-reversal invariant Bloch frames in dimensions 2 and 3. In 2d, the obstruction to the existence of such a frame is shown to be encoded in a $\mathbb{Z}_2$-valued topological invariant, which can be computed by a simple algorithm. We prove that the latter agrees with the Fu-Kane index. In 3d, instead, four $\mathbb{Z}_2$ invariants emerge from the construction, again related to the Fu-Kane-Mele indices. When no topological obstruction is present, we provide a constructive algorithm yielding explicitly a periodic and time-reversal invariant Bloch frame. The result is formulated in an abstract setting, so that it applies both to discrete models and to continuous ones.
description: 48 pages, 3 figures. Version 2: final version, to appear in CMP. A new section (Section 7), containing a proof of the completeness of the classification provided by the Z_2-invariants (Theorem 6), has been added. The behavior of the Z_2-indices with respect to a change of lattice basis, is now discussed at the end of Section 6.4
title: COVID-19 Crowd Detection
Creators: name: Ibrahim, Mustafa
name: Zeineldin, Aly M.
name: Khan, Yameen
name: Elmesalami, Ayman
name: Ibrahim, Soad
Publisher: name: Old Dominion University Libraries
Year: 2023

description: Object detection was introduced by researchers for face detection. Researchers explain how the detected face is divided into minor frames to be recognized by the algorithm. Due to COVID-19 and government regulations, many people face problems going to shopping centers and shop safely. It has been very hard for both the government and the people to manage social distancing. In our study, we developed a system using Raspberry Pi-4 that will detect the distance between people along with counting the number of distance and mask violations. An error message will appear on the screen in red, showing the total number of distance and mask violations, which could later be used by the customer as statistical evidence for better safety precautions.
Measuring Muon-Induced Neutrons with Liquid Scintillation Detector at Soudan Mine
Creators: name: Zhang, C.
name: Mei, D. -M.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We report a direct detection of muon-induced high energy neutrons with a 12-liter neutron detector fabricated with EJ-301 liquid scintillator operating at Soudan Mine for about two years. The detector response to energy from a few MeV up to $\sim$ 20 MeV has been calibrated using radioactive sources and cosmic-ray muons. Subsequently, we have calculated the scintillation efficiency for nuclear recoils, up to a few hundred MeV, using Birks' law in the Monte Carlo simulation. Data from an exposure of 655.1 days were analyzed and neutron-induced recoil events were observed in the energy region from 4 MeV to 50 MeV, corresponding to fast neutrons with kinetic energy up to a few hundred MeV, depending on the scattering angle. Combining with the Monte Carlo simulation, the muon-induced fast neutron flux is determined to be $(2.3 \pm 0.52 (sta.) \pm 0.99 (sys.) ) \times10^{-9}$ cm$^{-2}$s$^{-1}$ (E$_{n}$ $>$ 20 MeV), in a reasonable agreement with the model prediction. The muon flux is found to be ($1.65\pm 0.02 (sta.) \pm 0.1 (sys.) ) \times10^{-7}$ cm$^{-2}$s$^{-1}$ (E$_μ$ $>$ 1 GeV), consistent with other measurements. As a result, the muon-induced high energy gamma-ray flux is simulated to be 7.08 $\times$10$^{-7}$cm$^{-2}$s$^{-1}$ (E$_γ$ $>$ 1 MeV) for the depth of Soudan.
description: 13 pages, 20 figures, and 2 tables
Inflationary cosmology and the standard model Higgs with a small Hubble induced mass
Creators: name: Kamada, Kohei
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the dynamics of the standard model Higgs field in the inflationary cosmology. Since metastability of our vacuum is indicated by the current experimental data of the Higgs boson and top quark, inflation models with a large Hubble parameter may have a problem: In such models, the Higgs field rolls down towards the unwanted true vacuum due to the large fluctuation in the inflationary background. However, this problem can be relaxed by supposing an additional mass term for the Higgs field generated during and after inflation. We point out that it does not have to be larger than the Hubble parameter if the number of $e$-folds during inflation is not too large. We demonstrate that a high reheating temperature is favored in such a relatively small mass case and it can be checked by future gravitational wave observations. Such an induced mass can be generated by, {\it e.g.,} a direct coupling to the inflaton field or nonminimal coupling to gravity.
description: 25 pages, 5 figures; v2: typos corrected, references, figures, and extended discussions added, matches version published in PLB
Supplemental methods, results, figures, and tables from Jaw size variation is associated with a novel craniofacial function for galanin receptor 2 in an adaptive radiation of pupfishes
Creators: name: Palominos, M. Fernanda
name: Muhl, Vanessa
name: Richards, Emilie J.
name: Miller, Craig T.
name: Martin, Christopher H.
Publisher: name: The Royal Society
Year: 2023
Subjects: classificationCode: 310404
subject: Evolution of developmental systems
classificationCode: 310499
subject: Evolutionary biology not elsewhere classified

description: Understanding the genetic basis of novel adaptations in new species is a fundamental question in biology. Here we demonstrate a new role for galr2 in vertebrate craniofacial development using an adaptive radiation of trophic specialist pupfishes endemic to San Salvador Island, Bahamas. We confirmed the loss of a putative Sry transcription factor binding site upstream of galr2 in scale-eating pupfish and found significant spatial differences in galr2 expression among pupfish species in Meckel's cartilage using in situ hybridization chain reaction (HCR). We then experimentally demonstrated a novel function for Galr2 in craniofacial development by exposing embryos to Garl2-inhibiting drugs. Galr2-inhibition reduced Meckel's cartilage length and increased chondrocyte density in both trophic specialists but not in the generalist genetic background. We propose a mechanism for jaw elongation in scale-eaters based on reduced expression of galr2 due to the loss of a putative Sry binding site. Fewer Galr2 receptors in the scale-eater Meckel's cartilage may result in their enlarged jaw lengths as adults by limiting opportunities for a postulated Galr2 agonist to bind to these receptors during development. Our findings illustrate the growing utility of linking candidate adaptive SNPs in non-model systems with highly divergent phenotypes to novel vertebrate gene functions.
Swiss impact currency: improving the impact of currency systems for a sustainable economy in Switzerland
Creators: name: Place, Christophe
name: Calderon, Antonin
name: Stodder, James
name: Wallimann, Isidor
Publisher: name: International Journal of Community Currency Research (IJCCR)
Year: 2018
Subjects: Switzerland
Swiss
cross-border
WIR
Léman
NetzBon
cryptocurrency

description: Switzerland has not only the oldest and biggest modern complementarycurrency in the world, the WIR created in 1934, among 40’000organizations with a velocity of 1.3 in 2017, representing 0.17% ofthe Gross Domestic Product at current prices and 0.08% of the globalmoney supply, but also the second cross-border complementary currencyin the world and the first local currency using blockchain technologyin Switzerland, the Léman, created in September 2015 in a Swiss-Frenchconurbation, with 160’000 units in circulation among a network of 550organizations and 4’000 users in May 2018. Moreover, with about 49community currencies and 15 complementary currencies in January 2018and a cryptocurrency cluster called Crypto Valley funded in January2017, Switzerland counts among reference case studies in the virtual,community and complementary currency systems domain. Nevertheless,some questions remain: (1) How is the partition of these currencies interm of geographical region, system type and digital software? (2)What the recent Léman case study taught us in term of strategicimplementation? (3) Could a Swiss Currency Confederation facilitatetheir legal conformity? To contribute to these research questions, aliterature review, a data analysis, and a research survey will allowus not only to overview the Swiss and the Greater Geneva currencysystems, but also evaluate their legal framework evolution.
Nuclear Reactions from Lattice QCD
Creators: name: Briceño, Raúl A.
name: Davoudi, Zohreh
name: Luu, Thomas C.
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: One of the overarching goals of nuclear physics is to rigorously compute properties of hadronic systems directly from the fundamental theory of strong interactions, Quantum Chromodynamics (QCD). In particular, the hope is to perform reliable calculations of nuclear reactions which will impact our understanding of environments that occur during big bang nucleosynthesis, the evolution of stars and supernovae, and within nuclear reactors and high energy/density facilities. Such calculations, being truly ab initio, would include all two-nucleon and three- nucleon (and higher) interactions in a consistent manner. Currently, lattice QCD provides the only reliable option for performing calculations of some of the low- energy hadronic observables. With the aim of bridging the gap between lattice QCD and nuclear many-body physics, the Institute for Nuclear Theory held a workshop on Nuclear Reactions from Lattice QCD on March 2013. In this review article, we report on the topics discussed in this workshop and the path planned to move forward in the upcoming years.
description: 35 pages, 13 figures, 1 table, review article for the "Nuclear Reactions from Lattice QCD" workshop hosted by the Institute for Nuclear Theory on March 2013; version 2 includes updated references and extended discussion of previous work
Weighing the Giants IV: Cosmology and Neutrino Mass
Creators: name: Mantz, Adam B.
name: von der Linden, Anja
name: Allen, Steven W.
name: Applegate, Douglas E.
name: Kelly, Patrick L.
name: Morris, R. Glenn
name: Rapetti, David A.
name: Schmidt, Robert W.
name: Adhikari, Saroj
name: Allen, Mark T.
name: Burchat, Patricia R.
name: Burke, David L.
name: Cataneo, Matteo
name: Donovon, David
name: Ebeling, Harald
name: Shandera, Sarah
name: Wright, Adam
Publisher: name: arXiv
Year: 2014
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We employ robust weak gravitational lensing measurements to improve cosmological constraints from measurements of the galaxy cluster mass function and its evolution, using X-ray selected clusters detected in the ROSAT All-Sky Survey. Our lensing analysis constrains the absolute mass scale of such clusters at the 8 per cent level, including both statistical and systematic uncertainties. Combining it with the survey data and X-ray follow-up observations, we find a tight constraint on a combination of the mean matter density and late-time normalization of the matter power spectrum, $σ_8(Ω_m/0.3)^{0.17}=0.81\pm0.03$, with marginalized, one-dimensional constraints of $Ω_m=0.26\pm0.03$ and $σ_8=0.83\pm0.04$. For these two parameters, this represents a factor of two improvement in precision with respect to previous work, primarily due to the reduced systematic uncertainty in the absolute mass calibration provided by the lensing analysis. Our new results are in good agreement with constraints from cosmic microwave background (CMB) data, both WMAP and Planck (plus WMAP polarization), under the assumption of a flat $Λ$CDM cosmology with minimal neutrino mass. Consequently, we find no evidence for non-minimal neutrino mass from the combination of cluster data with CMB, supernova and baryon acoustic oscillation measurements, regardless of which all-sky CMB data set is used (and independent of the recent claimed detection of B-modes on degree scales). We also present improved constraints on models of dark energy (both constant and evolving), modifications of gravity, and primordial non-Gaussianity. Assuming flatness, the constraints for a constant dark energy equation of state from the cluster data alone are at the 15 per cent level, improving to $\sim 6$ per cent when the cluster data are combined with other leading probes.
description: 24 pages, 10 figures, 5 tables. v3: typo in table A1 corrected
title: Achtsamkeit, Psychological Detachment & Work-Life Conflict
Creators: name: Langenbeck, Marie Lou
Year: 2021

description: Ziel dieser Arbeit war es, Bedingungen und Wirkzusammenhänge zu untersuchen, die bei Mitarbeiter*innen das Empfinden auslösen, den Erwartungen ihres Privatlebens aufgrund der Arbeit nicht gerecht werden zu können. Da durch die Arbeit bedingte Konflikte im Privatleben (WLC) sowohl mit physischen als auch psychischen Gesundheitsfaktoren in Verbindung stehen, bestand ein weiteres Ziel darin, Achtsamkeit sowie das spezifische Achtsamkeitsprogramm MBSR als potenzielle Schutzfaktoren zu testen. Dafür wurde eine quantitative Querschnittstudie mittels eines Online-Fragebogens durchgeführt, welchen 213 Personen im Alter zwischen 21 und 81 Jahren (M = 46.29, SD = 13.47) aus Österreich und Deutschland abschlossen. Dabei stellte sich heraus, dass das Erleben von Zeitdruck bei der Arbeit mit einer geringeren Tendenz einhergeht, sich mental von der Arbeit zu lösen und dadurch mit Konflikten zwischen Arbeits-und Privatleben assoziiert ist. Weiter konnte festgestellt werden, dass Achtsamkeit die Fähigkeit zur mentalen Loslösung in der Freizeit bei Zeitdruck und hohen Konzentrationsanforderungen schützt und dadurch mit niedrigerem WLC assoziiert ist. Die Teilnahme am MBSR Programm stand entgegen den bisherigen Forschungsbefunden in Zusammenhang mit niedrigeren Achtsamkeitswerten und dem verstärkten Empfinden von WLC. Maßnahmen, um WLC zu reduzieren, sind zum einen die Reduktion von hohen Arbeitsanforderungen sowie der Schutz der Fähigkeit zur mentalen Ablösung während der Freizeit durch regelmäßige Achtsamkeitstrainings. Um weitere Handlungsimplikationen ableiten zu können, sollten zukünftige Studien nach weiteren Mechanismen für den Zusammenhang zwischen hohen Arbeitsanforderungen und WLC forschen und die Bedingungen zur langfristigen Förderung von Achtsamkeit untersuchen.
The need for improving diversity in the workplace : the case of shipping industry
Creators: name: Gourlia, Eugenia
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2022
Subjects: subject: Diversity in the workplace
subject: Women in shipping
subject: Work discrimination

description: Η παρούσια εργασία αναφέρεται στη διαφορετικότητα των ανθρώπων και πως αυτή πρέπει να είναι σεβαστή από όλους και στην καθημερινότητά μας και στο χώρο εργασίας μας. Γίνονται αναφορές των διαφόρων κατηγοριών της διαφορετικότητας και των μεθόδων που μπορεί να χρησιμοποιήσει μία εταιρεία ώστε να στηρίξει τη διαφορετικότητα και να προωθήσει το σεβασμό. Επίσης αναφερόμαστε στην αντιμετώπιση των γυναικών γενικότερα στο χώρο της Ναυτιλίας και στις πολιτισμικές διαφορές του πληρώματος των πλοίων και με ποιους τρόπους θα μπορούσαμε να βελτιώσουμε την επικοινωνία των υπαλλήλων.
Experimental violation of a d-dimensional Bell inequality using energy-time entangled photons
Creators: name: Schwarz, Sacha
name: Bessire, Bänz
name: Stefanov, André
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We experimentally study the violation of the CGLMP inequality for entangled 2-qubit and 2-qutrit states with different degrees of entanglement using numerically optimized measurement settings. The qudits are encoded and manipulated in the frequency spectrum of broadband energy-time entangled photons by taking into account a spatial light modulator. The latter allows to discretize the spectrum into bins. By controlling each frequency bin individually, the generation of maximally and non-maximally entangled qutrits is verified through quantum state tomography.
description: 7 pages, 3 figures
Η νομοθετική αντιμετώπιση του πολιτισμικού τουρισμού και ιδιαίτερα κατά την περίοδο της πανδημίας
Creators: name: Ξεινού, Αρτεμισία
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2022
Subjects: subject: Νομοθεσία
subject: Πολιτισμικός τουρισμός
subject: Πανδημία
subject: Επιπτώσεις

description: Ο τουρισμός αποτελεί αναπτυξιακό εργαλείο για αρκετές περιοχές παγκοσμίως σε τοπικό, περιφερειακό και εθνικό επίπεδο. Η αυξητική τάση των ταξιδιών παγκοσμίως έχει οδηγήσει αναπόφευκτα σε αύξηση του ανταγωνισμού μεταξύ των προορισμών και στη διαρκή προσπάθειά τους να προβάλλουν ελκυστικά τουριστικά προϊόντα. Αναφορικά με την Ελλάδα, το κυρίαρχο τουριστικό προϊόν είναι αυτό του μαζικού τουρισμού (ήλιος και θάλασσα), γεγονός που έχει χαρακτηρίσει τη ζήτηση αρκετών ελληνικών προορισμών. Παρ’ όλα αυτά, τα τελευταία χρόνια, παρατηρείται μία τάση προς την ανάπτυξη ειδικών και εναλλακτικών μορφών τουρισμού. Ειδικότερα στη συγκεκριμένη εργασία μελετάται το φαινόμενο του πολιτισμικού τουρισμού και το νομοθετικό πλαίσιο που τον διέπει, καθώς είναι μία μορφή τουρισμού ταχέως και ευρέως εξελισσόμενη. Δεν μπορεί να παραλειφθεί και η πανδημία που έχει πλήξει τον κόσμο εδώ και δύο χρόνια και ένας από τους τομείς που έχει πλήξει περισσότερο είναι ο τουρισμός. Συνεπώς, πρώτα θα αναλυθούν οι φορείς του ελληνικού τουρισμού γενικότερα στην Ελλάδα που προωθούν τον ελληνικό τουρισμού. Στη συνέχεια, θα αναλυθεί το προφίλ των πολιτιστικών τουριστών και η αγορά στον πολιτισμικό τουρισμό αλλά και στον τουρισμό γενικότερα. Σημαντικοί όροι θα αναλυθούν πριν προχωρήσουμε στη νομοθετική αντιμετώπιση του πολιτισμικού τουρισμού και παράλληλα θα γίνει αντιληπτή η σημασία του πολιτισμού στην οικονομία και πόσα οφέλη μπορεί να προσφέρει στην εκάστοτε χώρα. Έπειτα, θα απαριθμηθούν οι αρνητικές συνέπειες τις πανδημίας και τα μέτρα στήριξης που προσέφεραν διεθνείς και εγχώριοι φορείς και οργανισμοί για την στήριξη του πολιτισμού. Τέλος, θα δοθούν σημαντικοί τρόποι και σημαντικά μέσα που μπορεί να προωθηθεί ο πολιτισμικός τουρισμός, αποφέροντας οφέλη προς όλους τους ανθρώπους, την κοινωνία και την οικονομία της χώρας.
Inflaton as a pseudo-Goldstone boson of vacuum energy shift symmetry
Creators: name: Balitsky, Ja. V.
name: Kiselev, V. V.
Publisher: name: arXiv
Year: 2014
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The exact symmetry induced by the global shift of energy scale for the cosmological constant in the action of matter fields is spontaneously broken by setting the density of real vacuum energy and explicitly broken by the gravity that means the existence of Nambu--Goldstone boson, which transforms into the pseudo-Goldstone boson due to the gravity. We identify this boson with the inflaton in the Einstein frame of action for the fields, while the breaking is induced by a non-minimal interaction of boson with the scalar curvature in the Jordan frame. The role of Galilean symmetry of field equation is emphasized in the procedure of fixing some terms in the bare action.
description: 11 pages; calculations, comments, 2 figures and references added
A Statistical Reconstruction of the Planet Population Around Kepler Solar-Type Stars
Creators: name: Silburt, Ari
name: Gaidos, Eric
name: Wu, Yanqin
Publisher: name: arXiv
Year: 2014
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Using the cumulative catalog of planets detected by the NASA Kepler mission, we reconstruct the intrinsic occurrence of Earth- to Neptune-size (1 - 4$R_{\oplus}$) planets and their distributions with radius and orbital period. We analyze 76,711 solar-type ($0.8
description: 13 pages, 9 figures, 3 Tables. Accepted for publication in ApJ
Not so Coy Dark Matter explains DAMA (and the Galactic Center excess)
Creators: name: Arina, Chiara
name: Del Nobile, Eugenio
name: Panci, Paolo
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study a Dirac Dark Matter particle interacting with ordinary matter via the exchange of a light pseudo-scalar, and analyze its impact on both direct and indirect detection experiments. We show that this candidate can accommodate the long-standing DAMA modulated signal and yet be compatible with all exclusion limits at $99_S$ % CL. This result holds for natural choices of the pseudo-scalar-quark couplings (e.g.~flavor-universal), which give rise to a significant enhancement of the Dark Matter-proton coupling with respect to the coupling to neutrons. We also find that this candidate can accommodate the observed 1-3 GeV gamma-ray excess at the Galactic Center and at the same time have the correct relic density today. The model could be tested with measurements of rare meson decays, flavor changing processes, and searches for axion-like particles with mass in the MeV range.
description: 5+4 pages, 1+1 figure; Added constraints from the KIMS experiment and from the electron and muon anomalous magnetic moment; references added; conclusions unchanged; matches version published in PRL (with a different title)
Electro-hydrodynamics near Hydrophobic Surfaces
Creators: name: Maduar, S. R.
name: Belyaev, A. V.
name: Lobaskin, V.
name: Vinogradova, O. I.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences
subject: J.2

description: We show that an electro-osmotic flow near the slippery hydrophobic surface depends strongly on the mobility of surface charges, which are balanced by counter-ions of the electrostatic diffuse layer. For a hydrophobic surface with immobile charges the fluid transport is considerably amplified by the existence of a hydrodynamic slippage. In contrast, near the hydrophobic surface with mobile adsorbed charges it is also controlled by an additional electric force, which increases the shear stress at the slipping interface. To account for this, we formulate electro-hydrodynamic boundary conditions at the slipping interface, which should be applied to quantify electro-osmotic flows instead of hydrodynamic boundary conditions. Our theoretical predictions are fully supported by dissipative particle dynamics simulations with explicit charges. These results lead to a new interpretation of zeta-potential of hydrophobic surfaces.
description: 5 pages, 6 figures
Fuel consumption strategies using digital business
Creators: name: Γιαλαμά-Χανιωτάκη, Ασπασία-Στυλιανή
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2022
Subjects: subject: Shipping
subject: Big data
subject: Fuel consumption
subject: Energy efficiensy

description: Η βελτιστοποίηση της απόδοσης του πλοίου είναι σήμερα μια επείγουσα ανάγκη τόσο για τη μείωση του λειτουργικού κόστους του στόλου όσο και για τη μείωση των εκπομπών αερίων του θερμοκηπίου. Σκοπός της παρούσας διπλωματικής εργασίας είναι να εξετάσει πώς οι καιρικές συνθήκες μπορούν να επηρεάσουν την κατανάλωση καυσίμου στα πλοία και σε ποιο βαθμό. Πιο συγκεκριμένα, στόχος της παρούσας μελέτης είναι να διερευνήσει τις συσχετίσεις μεταξύ των διαφόρων παραγόντων που επηρεάζουν την ενεργειακή απόδοση των πλοίων, τόσο μέσω της περιγραφής του θεωρητικού υποβάθρου όσο και μέσω μιας πρακτικής ανάλυσης ενός συνόλου δεδομένων που προέρχονται από την πραγματική λειτουργία ενός στόλο δύο δεξαμενόπλοιων. Μια τέτοια ανάλυση μπορεί να ενσωματωθεί στο σύστημα διαχείρισης ενέργειας εταιρειών με παρόμοια πλοία, καθώς μπορεί να βοηθήσει τους φορείς εκμετάλλευσης πλοίων στην επιλογή των πιο αποτελεσματικών μέτρων προκειμένου όχι μόνο να επιτύχουν την απόδοση καυσίμου και τη διαρκή λειτουργική απόδοση του σκάφους αλλά και να μειώσουν τις εκπομπές ρύπων, γεγονός που θα οδηγήσει επίσης σε χαμηλότερο λειτουργικό κόστος για τη ναυτιλιακή εταιρεία.
Metastable vacuum decay and $θ$ dependence in gauge theory. Deformed QCD as a toy model
Creators: name: Bhoonah, Amit
name: Thomas, Evan
name: Zhitnitsky, Ariel R.
Publisher: name: arXiv
Year: 2014
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study a number of different ingredients related to the $θ$ dependence, metastable excited vacuum states and other related subjects using a simplified version of QCD, the so-called "deformed QCD". This model is a weakly coupled gauge theory, which however preserves all the relevant essential elements allowing us to study hard and nontrivial features which are known to be present in real strongly coupled QCD. Our main focus in this work is to test the ideas related to the metastable vacuum states (which are known to be present in strongly coupled QCD in large $N$ limit) in a theoretically controllable manner using the "deformed QCD" as a toy model. We explicitly show how the metastable states emerge in the system, why their life time is large, and why these metastable states must be present in the system for the self-consistency of the entire picture of the QCD vacuum. We also speculate on possible relevance of the metastable vacuum states in explanation of the violation of local $\cal{P}$ and $\cal{CP}$ symmetries in heavy ion collisions.
description: Version 2 updated to reflect version published in Nuclear Physics B
Στοχαστικά μοντέλα στη θεωρία κινδύνου με εξάρτηση και διάχυση
Creators: name: Αναγνωσταράς, Γεώργιος
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2022
Subjects: subject: Θεωρία χρεοκοπίας
subject: Δομή εξάρτησης
subject: Στοχαστικά μοντέλα

description: Στη θεωρία χρεοκοπίας, για πόλλα χρόνια, ήταν σύνηθες για την μοντελοποίηση της στοχαστικής διαδικασίας του πλεονάσματος να χρησιμοποίειται το μοντέλο Cramer-Lundberg (κλασσικό μοντέλο) ή το ανανεωτικό μοντέλο (μοντέλο Sparre-Andersen).Απαραίτητη προϋπόθεση για την χρήση των παραπάνω μοντέλων είναι η ύπαρξη ανεξαρτησίας μεταξύ του ύψους των ζημιών (ατομικών απαιτήσεων) και των ενδιάμεσων χρόνων εμφάνισης ζημιογόνων ενδεχομένων.Στην πραγματικότητα όμως κάτι τέτειο δεν υφίσταται πάντα, έτσι τα τελευταία χρόνια η έρευνα έχει επικεντρωθεί στη μελέτη και ανάπτυξη μοντέλων με εξάρτηση.Στην παρούσα διπλωματική θα αναπτυχθεί ένα μοντέλο στο οποίο η κατανομή του χρόνου μέχρι την επόμενη απαίτηση εξαρτάται από το ύψος της προηγούμενης απαίτησης, δηλαδή η κατανομή του ενδιάμεσου χρόνου μεταξύ δύο διαδοχικών απαιτήσεων εξαρτάται από το ύψος της απαίτησης που προηγείται χρονικά.Στα πρώτα δύο κεφάλαια παρουσιάζοντε βασικά αποτελέσματα της θεωρίας των στοχαστικών διαδικασιών, της θεωρίας χρεοκοπίας κάθως και χρήσιμες έννοιες για τα επόμενα κεφάλαια.Στο τρίτο κεφάλαιο εισάγεται ένα μοντέλο με την παραπάνω δομή εξάρτησης ενώ αναπτύσεται για τo μοντέλο αυτό η γενικευμένη εξίσωση Lundberg καθώς και η συνάρτηση των Gerber-Shiu αλλά και χρήσιμες ποσότητες όπως ο μετασχηματισμός Laplace του χρόνου χρεοκοπίας,ενώ παρατίθενται και αριθμητικά παραδείγματα. Στο τέταρτο κεφάλαιο στο μοντέλο με εξάρτηση εισάγεται ένας όρος διάχυσης και η εργασία επικεντρώνεται στην εξίσωση Lundberg, στη συνάρτηση Gerber-Shiu (με σκοπό την εξαγωγή μέτρων χρεοκοπίας) στο μετασχηματισμό Laplace για το χρόνο χρεοκοπίας (όπως και στο τρίτο κεφάλαιο) αλλά και στην μελέτη ολοκληροδιαφορικών εξισώσεων για το συγκεκριμένο μοντέλο. Στο πέμπτο κεφάλαιο εισάγεται και αναλύεται ένα δυϊκό μοντέλο με εξάρτηση αλλά και παράγοντα διάχυσης και παρουσιάζεται ο μετασχηματισμός Laplace για τη στιγμή της χρεοκοπίας.
Machbarkeitsstudie zur Ex-situ-Erhaltungszucht des Feuersalamanders (Salamandra salamandra) - Das Beispiel Bayern
Creators: name: Penner, Johannes
name: Werning, Heiko
name: Dubberke, Vanessa
name: Patanant, Kidan
name: Rödel, Mark-Oliver
name: Encke, Björn
Publisher: name: Zenodo
Year: 2022
Subjects: Batrachochytrium salamandrivorans
Fire salamander
Ex situ conservation
Artenhilfsprogramm Feuersalamander Bayern
Landesbund für Vogel- und Naturschutz in Bayern (LBV)
Bund Naturschutz in Bayern (BUND)
Landesverband für Amphibien- und Reptilienschutz Bayern (LARS)
Frogs and Friends
Citizen Conservation

description: The European Fire salamander is acutely threatened by the chytrid fungus Bsal. Currently no possibility exists to combat Bsal in nature, thus an ex situ conservation programme is necessary. Different possibilities and the current state of knowledge are presented. Spreading of risks through different husbandry systems and different locations is recommended. A first framework is provided through cost estimates for different scenarios and an initial starting phase as an immediate measure.
description: https://citizen-conservation.org/feuersalamander/ https://www.lbv.de/news/details/artenhilfsprogramm-feuersalamander-in-bayern/ https://www.bund-naturschutz.de/tiere-in-bayern/amphibien/schwanzlurche/feuersalamander/artenhilfsprogramm-feuersalamander https://www.lars-ev.de/
title: 'Ringu' und 'The Ring' im Vergleich
Creators: name: Fuchs, Lukas
Year: 2021

description: Der japanische Horrorfilm hat in den letzten beiden Jahrzehnten im Westen stark an Popularität gewonnen. Dies zeigt sich unter anderem auch in einer steigenden Anzahl von Remakes aus Hollywood, die sich an den modernen Horrorfilmen aus Japan orientieren. Oftmals wird der Plot des Originals übernommen, das Endprodukt unterscheidet sich aber oft deutlich davon. Die Gründe dieser unterschiedlichen Darstellungen von Horror und der Umgang im Film damit sind sowohl historisch als auch kulturell begründet und werden in dieser Arbeit gegenübergestellt. Forschungsobjekt ist der japanische Film Ringu und sein Remake The Ring. Ersterer zählt zu den wegweisenden Filmen des Horrorgenres in den späten 90er Jahren und wird als einer der Mitbegründer des modernen japanischen Horrorfilms angesehen. Die Analyse behandelt die unterschiedlichen Methoden, die in den Filmen eingesetzt werden, um im jeweiligen Publikum das Gefühl von Horror und Schrecken zu erzeugen. Hierbei wird sowohl die akustische Ebene behandelt als auch Mise en Scène und der Schnitt. Aussagekräftige Szenen werden unter diesen Aspekten untersucht um so einen Vergleich zwischen dem japanischen Film und dem Remake, das sich im Gegensatz zum regional ausgerichtetem Original stärker an ein globales Publikum richtet, aufzustellen. Besonders seit der Auszeichnung des koreanischen Films Parasite rückt der ostasiatische Film stärker in den globalen Vordergrund. Die vorliegende Arbeit liefert hierzu einen Ansatzpunkt anhand einer Analyse der Entwicklung im westlichen Umgang mit dem ostasiatischen Film.
New numerical solver for flows at various Mach numbers
Creators: name: Miczek, F.
name: Roepke, F. K.
name: Edelmann, P. V. F.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Computational Physics (physics.comp-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Many problems in stellar astrophysics feature flows at low Mach numbers. Conventional compressible hydrodynamics schemes frequently used in the field have been developed for the transonic regime and exhibit excessive numerical dissipation for these flows. While schemes were proposed that solve hydrodynamics strictly in the low Mach regime and thus restrict their applicability, we aim at developing a scheme that correctly operates in a wide range of Mach numbers. Based on an analysis of the asymptotic behavior of the Euler equations in the low Mach limit we propose a novel scheme that is able to maintain a low Mach number flow setup while retaining all effects of compressibility. This is achieved by a suitable modification of the well-known Roe solver. Numerical tests demonstrate the capability of this new scheme to reproduce slow flow structures even in moderate numerical resolution. Our scheme provides a promising approach to a consistent multidimensional hydrodynamical treatment of astrophysical low Mach number problems such as convection, instabilities, and mixing in stellar evolution.
description: 16 pages, 8 figures, accepted for publication by A&A
A catalogue of 2D photometric decompositions in the SDSS-DR7 spectroscopic main galaxy sample: preferred models and systematics
Creators: name: Meert, Alan
name: Vikram, Vinu
name: Bernardi, Mariangela
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present a catalogue of two-dimensional, point spread function-corrected de Vacouleurs, Sérsic, de Vacouleurs+Exponential, and Sérsic+Exponential fits of $\sim7\times10^5$ spectroscopically selected galaxies drawn from the Sloan Digital Sky Survey (SDSS) Data Release 7. Fits are performed for the SDSS r band utilizing the fitting routine GALFIT and analysis pipeline PYMORPH. We compare these fits to prior catalogues. Fits are analysed using a physically motivated flagging system. The flags suggest that more than 90 per cent of two-component fits can be used for analysis. We show that the fits follow the expected behaviour for early and late galaxy types. The catalogues provide a robust set of structural and photometric parameters for future galaxy studies. We show that some biases remain in the measurements, e.g. the presence of bars significantly affect the bulge measurements although the bulge ellipticity may be used to separate barred and non-barred galaxies, and about 15 percent of bulges of two-component fits are also affected by resolution. The catalogues are available in electronic format. We also provide an interface for generating postage stamp images of the 2D model and residual as well as the 1D profile. These images can be generated for a user-uploaded list of galaxies on demand.
description: Main Text: 36 pages, 27 figures; Appendix: 19 pages, 21 figures; Version Accepted to MNRAS; The catalog is available at http://shalaowai.physics.upenn.edu/~ameert/fit_catalog/
title: Διασύνδεση της ψηφιακής πληροφορίας με το φυσικό προϊόν στην εφοδιαστική αλυσίδα – Γραμμωτοί κώδικες
title: Interconnection of digital information with the physical product in the supply chain - Barcodes
titleType: AlternativeTitle
Creators: name: Μπαρμπούνης, Ιωάννης
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2022
Subjects: subject: Ιχνηλασιμότητα
subject: Γραμμωτοί κώδικες
subject: Barcodes

description: Στη συγκεκριμένη μεταπτυχιακή διατριβή εξετάζονται οι σύγχρονες ανάγκες της εφοδιαστικής αλυσίδας και ειδικά ο τομέας της ιχνηλασιμότητας. Δίνεται το στίγμα του ευρύτερου χώρου της αυτόματης αναγνώρισης και κτήσης δεδομένων στην εποχή μας. Εξετάζεται η τεχνολογία του γραμμωτού κώδικα και αναλύονται οι διάφορες κατηγορίες και τύποι γραμμωτού κώδικα, όπως οι γραμμικοί γραμμωτοί κώδικες (linear barcodes) και οι δισδιάστατοι γραμμωτοί κώδικες (2D barcodes) με τον ευρέως γνωστό κώδικα ταχείας απόκρισης (QR Code). Αναφέρονται τα βασικά χαρακτηριστικά και χρήσεις της τεχνολογίας γραμμωτού κώδικα στην εφοδιαστική αλυσίδα καθώς και τα κύρια βήματα υλοποίησής της σε μια εταιρία. Τέλος καταγράφονται οι εξελίξεις της τεχνολογίας γραμμωτού κώδικα καθώς και η συνέργειά της με άλλες σύγχρονες τεχνολογίες. Μέσα από τη συγκεκριμένη μελέτη εμφαίνονται τα θετικά χαρακτηριστικά της τεχνολογίας του γραμμωτού κώδικα που σε συνδυασμό με τις σημαντικές εξελίξεις κυρίως στο χώρο της πληροφορικής την καθιστούν βιώσιμη, διαχρονική και ιδιαίτερα χρήσιμη για την εφοδιαστική αλυσίδα στα πλαίσια της 4ης βιομηχανικής επανάστασης αλλά και της επερχόμενης 5ης βιομηχανικής επανάστασης.
Emulating quantum state transfer through a spin-1 chain on a 1D lattice of superconducting qutrits
Creators: name: Ghosh, Joydip
Publisher: name: arXiv
Year: 2014
Subjects: subject: Quantum Physics (quant-ph)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Spin-1 systems, in comparison to spin-1/2 systems, offer a better security for encoding and transfer of quantum information, primarily due to their larger Hilbert spaces. Superconducting artificial atoms possess multiple energy-levels, thereby capable of emulating higher-spin systems. Here we consider a 1D lattice of nearest-neighbor-coupled superconducting transmon systems, and devise a scheme to transfer an arbitrary qutrit-state (a state encoded in a three-level quantum system) across the chain. We assume adjustable couplings between adjacent transmons, derive an analytic constraint for the control-pulse, and show how to satisfy the constraint to achieve a high-fidelity state-transfer under current experimental conditions. Our protocol thus enables enhanced quantum communication and information processing with promising superconducting qutrits.
description: 13 pages, 3 figures. Accepted in Phys. Rev. A
A computational approach to the Thompson group $F$
Creators: name: Haagerup, S.
name: Haagerup, U.
name: Ramirez-Solano, M.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Group Theory (math.GR)
subject: Operator Algebras (math.OA)
subject: FOS: Mathematics
subject: 20F65, 20-04, 43A07, 22D25, 46L05

description: Let $F$ denote the Thompson group with standard generators $A=x_0$, $B=x_1$. It is a long standing open problem whether $F$ is an amenable group. By a result of Kesten from 1959, amenability of $F$ is equivalent to $$(i)\qquad ||I+A+B||=3$$ and to $$(ii)\qquad ||A+A^{-1}+B+B^{-1}||=4,$$ where in both cases the norm of an element in the group ring $\mathbb{C} F$ is computed in $B(\ell^2(F))$ via the regular representation of $F$. By extensive numerical computations, we obtain precise lower bounds for the norms in $(i)$ and $(ii)$, as well as good estimates of the spectral distributions of $(I+A+B)^*(I+A+B)$ and of $A+A^{-1}+B+B^{-1}$ with respect to the tracial state $τ$ on the group von Neumann Algebra $L(F)$. Our computational results suggest, that $$||I+A+B||\approx 2.95 \qquad ||A+A^{-1}+B+B^{-1}||\approx 3.87.$$ It is however hard to obtain precise upper bounds for the norms, and our methods cannot be used to prove non-amenability of $F$.
description: appears in International Journal of Algebra and Computation (2015)