cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Point Defects in Twisted Bilayer Graphene: A Density Functional Theory Study
Creators: name: Ulman, Kanchan
name: Narasimhan, Shobhana
Publisher: name: arXiv
Year: 2014
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We have used ab initio density functional theory, incorporating van der Waals corrections, to study twisted bilayer graphene (TBLG) where Stone-Wales defects or monovacancies are introduced in one of the layers. We compare these results to those for defects in single layer graphene or Bernal stacked graphene. The energetics of defect formation is not very sensitive to the stacking of the layers or the specific site at which the defect is created, suggesting a weak interlayer coupling. However signatures of the interlayer coupling are manifested clearly in the electronic band structure. For the "$γγ$" Stone Wales defect in TBLG, we observe two Dirac cones that are shifted in both momentum space and energy. This up/down shift in energy results from the combined effect of a charge transfer between the two graphene layers, and a chemical interaction between the layers, which mimics the effects of a transverse electric field. Charge density plots show that states near the Dirac points have significant admixture between the two layers. For Stone Wales defects at other sites in TBLG, this basic structure is modified by the creation of mini gaps at energy crossings. For a monovacancy, the Dirac cone of the pristine layer is shifted up in energy by $\sim0.25$ eV due to a combination of the requirements of the equilibration of Fermi energy between the two layers with different numbers of electrons, charge transfer, and chemical interactions. Both kinds of defects increase the density of states at the Fermi level. The monovacancy also results in spin polarization, with magnetic moments on the defect of 1.2 - 1.8 $μ_B$.
description: 17 pages, 42 figures
Correspondence between Dicke-model semiclasscial dynamics in the superradiant dipolar phase and the Euler heavy top
Creators: name: Mukhin, S. I.
name: Mukherjee, A.
name: Seidov, S. S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: Analytic expression is found for the frequency dependence of transmission coefficient of a transmission line inductively coupled to the microwave cavity with superradiant condensate. Sharp transmission drops reflect condensate's frequencies spectrum. These results pave way to direct detection of emergence of the superradiant condensates in quantum metamaterials. Results are based on the analytic solutions of the nonlinear semiclassical dynamics of superradiant photonic condensate in the Dicke model of an ensemble of two-level atoms dipolar coupled to the electromagnetic field in the microwave cavity. In adiabatic limit with respect to photon degree of freedom the system is approximately integrable, with evolution being expressed via Jacobi elliptic functions of real time. Depending on the coupling strength, the semiclassical coordinate of superradiant condensate in the ground state either oscillates in one of the two degenerate minima of condensate's potential energy or traverses between them over the saddle point. An experimental setup for measuring of the breakdown of the normal phase of the Dicke model via coupling to the transmission line is proposed. A one-to-one mapping of semiclassical motion of superradiant condensate on the nodding of unstable Lagrange "sleeping top" also turns Dicke model into analogue device for modelling dynamics of mechanical systems.
Numerical solving the boundary value problem for fractional powers of elliptic operators
Creators: name: Vabishchevich, Petr N.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 35R11, 65F60, 65M06, 65N22

description: A boundary value problem for a fractional power of the second-order elliptic operator is considered. It is solved numerically using a time-dependent problem for a pseudo-parabolic equation. For the auxiliary Cauchy problem, the standard two-level schemes with weights are applied. Stability conditions are obtained for the fully discrete schemes under the consideration. The numerical results are presented for a model two-dimensional boundary value problem wit a fractional power of an elliptic operator. The dependence of accuracy on grids in time and in space is studied.
description: 18 pages, 17 figures
Ο Λαβύρινθος των ΕΕΕΕΚ, κοινωνικές ιεραρχίες και το θεσμικό αφήγημα της ένταξης
Creators: name: Λαζαρίδου, Χριστίνα Σπυρίδωνος
Publisher: name: Aristotle University of Thessaloniki
Year: 2023
Subjects: Ειδικά Εργαστήρια Επαγγελματικής Εκπαίδευσης
Αναπηρία
Εκπαίδευση
Vocational Education and Training
Disability
Education

description: Η παρούσα διπλωματική εργασία μελετά τους τρόπους με τους οποίους γίνεται αντιληπτή η αναπηρική ταυτότητα στον χώρο των Εργαστηρίων Ειδικής Επαγγελματικής Εκπαίδευσης και Κατάρτισης (ΕΕΕΕΚ). Εξετάζεται η σημασία της εννοιολόγησης της αναπηρίας και οι τρόποι που οι κυρίαρχες αφηγήσεις επηρεάζουν την υφιστάμενη εκπαιδευτική πολιτική, το θεσμικό πλαίσιο το οποίο οριοθετεί την ύπαρξη της δομής, οι προσωπικές αντιλήψεις του προσωπικού των ΕΕΕΕΚ για την αναπηρία και οι πρακτικές τους. Με εργαλεία την επιτόπια παρατήρηση και τις ημι-δομημένες συνεντεύξεις, η έρευνα στοχεύει να κατανοήσει τους τρόπους με τους οποίους επηρεάζονται οι αντιλήψεις και οι πρακτικές του προσωπικού των ΕΕΕΕΚ από το θεσμικό πλαίσιο και τον κυρίαρχο θεσμικό Λόγο.
description: This research study attempts to gain knowledge in the ways that the disabled identity is perceived in Special Vocational High Schools and Special Vocational Education and Training Laboratories. The study examines the importance of conceptualizing disability and the ways that dominant narratives influence the existing educational policy, the institutional framework that delimits the existence of the institution, the personal perception of people working there and their practices. Using field observation and semi-structured interviews, this study aims to understand the ways in which this institution’s staff perceptions and practices are influenced by the institutional context and the dominant institutional Discourse.
title: Wait ‘Til You See it From the Back: Twerking as an Expression of Sexual Agency
Creators: name: Johnson, Mariah M.
Publisher: name: Old Dominion University Libraries
Year: 2018

description: This paper attempts to examine racism, respectability politics, and its relation to twerking. With the use of research by Gilbert Herdt, Stanley Cohen, Marshall McLuhan, Dr. Tamura Lomax, Patricia Hill-Collins, Evelyn Brooks Higginbotham and many others to put the use of Black women as modern day folk devils into perspective.

Trigger Warning: Racism, Sexual Assault
Implications for the hierarchy problem, inflation and geodesic motion from fiber fabric of spacetime
Creators: name: Nam, Cao H.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: In this paper, we represent a resolution for the hierarchy problem where the inverse size of the extra dimension and the fundamental Planck scale would all be of the order of the TeV scale by proposing a fiber fabric of spacetime. The origin of the large hierarchy is essentially due to the $\cosh$ function which has a physical origin from the dynamics of the horizontal metric in the vacuum of non-zero energy. In addition, the fiber fabric of spacetime allows us to resolve elegantly and naturally the problems of the chirality fermions and stabilizing potential for the size of the extra dimension, which are usually encountered in the higher dimensional theories. Then, we explore the inflation with the modulus of the extra dimension identified as the inflaton where our slow-roll inflationary model belongs to the E-model class with $n=1$. We calculate the main inflationary observables which are consistent with the present experiments. Finally, we study how the geodesic motion of neutral test particles gets modified from the extension of spacetime. We compute the radius of the photon sphere, the innermost stable circular orbit, the perihelion shift, the light bending angle, and the observables of the strong gravitational lensing and the retrolensing phenomenon. By comparing the predicted values with the experimental observations, we determine the constraints on the fiber fabric of spacetime.
description: 45 pages, 11 figures. v3: references added
Dynamic Posted-Price Mechanisms for the Blockchain Transaction Fee Market
Creators: name: Ferreira, Matheus V. X.
name: Moroz, Daniel J.
name: Parkes, David C.
name: Stern, Mitchell
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Science and Game Theory (cs.GT)
subject: Cryptography and Security (cs.CR)
subject: Theoretical Economics (econ.TH)
subject: Optimization and Control (math.OC)
subject: FOS: Computer and information sciences
subject: FOS: Economics and business
subject: FOS: Mathematics

description: In recent years, prominent blockchain systems such as Bitcoin and Ethereum have experienced explosive growth in transaction volume, leading to frequent surges in demand for limited block space and causing transaction fees to fluctuate by orders of magnitude. Existing systems sell space using first-price auctions; however, users find it difficult to estimate how much they need to bid in order to get their transactions accepted onto the chain. If they bid too low, their transactions can have long confirmation times. If they bid too high, they pay larger fees than necessary. In light of these issues, new transaction fee mechanisms have been proposed, most notably EIP-1559, aiming to provide better usability. EIP-1559 is a history-dependent mechanism that relies on block utilization to adjust a base fee. We propose an alternative design -- a {\em dynamic posted-price mechanism} -- which uses not only block utilization but also observable bids from past blocks to compute a posted price for subsequent blocks. We show its potential to reduce price volatility by providing examples for which the prices of EIP-1559 are unstable while the prices of the proposed mechanism are stable. More generally, whenever the demand for the blockchain stabilizes, we ask if our mechanism is able to converge to a stable state. Our main result provides sufficient conditions in a probabilistic setting for which the proposed mechanism is approximately welfare optimal and the prices are stable. Our main technical contribution towards establishing stability is an iterative algorithm that, given oracle access to a Lipschitz continuous and strictly concave function $f$, converges to a fixed point of $f$.
FREYA PID Graph Services
Creators: name: Fenner, Martin
Publisher: name: Zenodo
Year: 2020
Subjects: Persistent Identifiers
PID Graph

description: Presentation of the PID Graph services developed in the FREYA project. The presentation was given as part of a session on PID Graph services in the context of the "Realising the EOSC event" on November 16th 2020.
On convergence rates of adaptive ensemble Kalman inversion for linear ill-posed problems
Creators: name: Parzer, Fabian
name: Scherzer, Otmar
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65J20, 65J22, 65F22

description: In this paper we discuss a deterministic form of ensemble Kalman inversion as a regularization method for linear inverse problems. By interpreting ensemble Kalman inversion as a low-rank approximation of Tikhonov regularization, we are able to introduce a new sampling scheme based on the Nyström method that improves practical performance. Furthermore, we formulate an adaptive version of ensemble Kalman inversion where the sample size is coupled with the regularization parameter. We prove that the proposed scheme yields an order optimal regularization method under standard assumptions if the discrepancy principle is used as a stopping criterion. The paper concludes with a numerical comparison of the discussed methods for an inverse problem of the Radon transform.
Τα καλλιτεχνικά ρεύματα του 18ου και 19ου αι. στη γλυπτική και ξυλογλυπτική του Αγίου Όρους
Creators: name: Μαργαρώνη, Παναγιώτα Παναγιώτη
Publisher: name: Aristotle University of Thessaloniki
Year: 2023
Subjects: Γλυπτική
Ξυλογλυπτική
Καλλιτεχνικά ρεύματα
Sculpture
Woodcarving
Artistic trends

description: Η διπλωματική εργασία με θέμα « Τα καλλιτεχνικά ρεύματα του 18ου και 19ου αιώνα στη γλυπτική και ξυλογλυπτική του Αγίου Όρους» έχει σαν στόχο να μελετήσει το ύφος και τα τεχνοτροπικά γνωρίσματα των έργων γλυπτικής και ξυλογλυπτικής στο Άγιο Όρος κατά τη μεταβυζαντινή περίοδο. Πρόκειται για αξιόλογη καλλιτεχνική παραγωγή, που αποτελεί αναπόσπαστο τμήμα της παραγωγής του ευρύτερου ελλαδικού χώρου. Δίνεται έμφαση στα κυρίαρχα καλλιτεχνικά ρεύματα της περιόδου (μπαρόκ, κλασικισμός) και παράλληλα ερευνάται το ζήτημα της προέλευσης και του καλλιτεχνικού περιβάλλοντος των έργων. Παρουσιάζεται το έργο ανώνυμων και επώνυμων γλυπτών και ξυλογλυπτών, που με την δραστηριότητά τους επηρέασαν με καίριο τρόπο την ανάπτυξη των δύο αυτών τεχνών. Στο Άγιο Όρος, που αποτελεί την πιο πλούσια σε ποιότητα και ποσότητα περιοχή της Ελλάδας με έργα ορθόδοξης χριστιανικής τέχνης υπάρχει ένας μεγάλος αριθμός λιθανάγλυφων και ξυλόγλυπτων έργων υψηλής αισθητικής, όπου μπορεί να παρατηρήσει κανείς σταδιακά την εξέλιξη της θρησκευτικής γλυπτικής και ξυλογλυπτικής. Η άρτια τεχνική, το πλούσιο θεματικό λεξιλόγιο, η ποικιλία στο ύφος των συνθέσεων και η ώσμωση συχνά ετερόκλητων στοιχείων στα έργα της περιόδου καθιστούν ιδιαίτερα ενδιαφέρον το θέμα της παρούσας εργασίας σε συνδυασμό με το γεγονός ότι η έρευνα για την καλλιτεχνική παραγωγή στην αθωνική πολιτεία εξακολουθεί να βρίσκεται σε εξέλιξη, ιδιαίτερα όσον αφορά τη μεταβυζαντινή περίοδο, καθώς τότε εντοπίζεται και ο μεγαλύτερος αριθμός έργων.
description: The present thesis is titled “The artistic trends of the 18th and 19th century in the sculpture and woodcarving of Mount Athos». The main purpose of this study is to analyze the style and technotropy of these works during post-Byzantine period. There is- during that period -remarkable art production, which is indefeasible part of similar production across the wider Greek space. Emphasis is given on major dominant artistic trends of the period (baroque, classicism) and at the same time thesis investigates the origins of art environment of these works. It is also presented the work of anonymous and branded sculptors and woodcarvers, who with their activity, in a timely manner, they managed to influence the development of these two arts. In the Mount Athos there is the richest quality and quantity of art works in Eastern Church (“Orthodox”). A huge number of fine aesthetic stone-repose and woodcarving is available for observers to investigate the evolution of these fine arts. Special interest is focused on the combination between fine techniques, rich thematic vocabulary, variety of synthesis styles, osmosis of heteroclite elements. There is continuous research of this mass production in Athos, especially on post- Byzantine period, where the huge number of works are being.
Blowup issues for a class of nonlinear dispersive wave equations
Creators: name: Brandolese, Lorenzo
name: Cortez, Manuel Fernando
Publisher: name: arXiv
Year: 2014
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: In this paper we consider the nonlinear dispersive wave equation on the real line, $u_t-u_{txx}+[f(u)]_x-[f(u)]_{xxx}+\bigl[g(u)+\frac{f''(u)}{2}u_x^2\bigr]_x=0$, that for appropriate choices of the functions $f$ and $g$ includes well known models, such as Dai's equation for the study of vibrations inside elastic rods or the Camassa--Holm equation modelling water wave propagation in shallow water. We establish a local-in-space blowup criterion (i.e., a criterion involving only the properties of the data $u_0$ in a neighbourhood of a single point) simplifying and extending earlier blowup criteria for this equation. Our arguments apply both to the finite and infinite energy case, yielding the finite time blowup of strong solutions with possibly different behavior as $x\to+\infty$ and $x\to-\infty$.
Individual project on theme "Allium L." (MOOC: CompTech in biology)
Creators: name: Kristina, Medvedeva
Publisher: name: Zenodo
Year: 2020

description: Данный кейс является результатом реализации индивидуального проекта Медведевой Кристины по теме "Allium L." в рамках онлайн курса "Компьютерные технологии в биологии" (автор – А.В. Ваганов) (https://stepik.org/course/60859/promo)
Fundamental weight systems are quantum states
Creators: name: Corfield, David
name: Sati, Hisham
name: Schreiber, Urs
Publisher: name: arXiv
Year: 2021
Subjects: subject: Geometric Topology (math.GT)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: Combinatorics (math.CO)
subject: Quantum Physics (quant-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: Weight systems on chord diagrams play a central role in knot theory and Chern-Simons theory; and more recently in stringy quantum gravity. We highlight that the noncommutative algebra of horizontal chord diagrams is canonically a star-algebra, and ask which weight systems are positive with respect to this structure; hence we ask: Which weight systems are quantum states, if horizontal chord diagrams are quantum observables? We observe that the fundamental gl(n)-weight systems on horizontal chord diagrams with N strands may be identified with the Cayley distance kernel at inverse temperature beta=ln(n) on the symmetric group on N elements. In contrast to related kernels like the Mallows kernel, the positivity of the Cayley distance kernel had remained open. We characterize its phases of indefinite, semi-definite and definite positivity, in dependence of the inverse temperature beta; and we prove that the Cayley distance kernel is positive (semi-)definite at beta=ln(n) for all n=1,2,3,... In particular, this proves that all fundamental gl(n)-weight systems are quantum states, and hence so are all their convex combinations. We close with briefly recalling how, under our "Hypothesis H", this result impacts on the identification of bound states of multiple M5-branes.
description: 21 pages; 1 figure; v2: bound sharpened
Vertical Clustering of 3D Elliptical Helical Data
Creators: name: Samarathunga, Wasantha
name: Seki, Masatoshi
name: Saito, Hidenobu
name: Ichiryu, Ken
name: Ohyama, Yasuhiro
Publisher: name: arXiv
Year: 2014
Subjects: subject: Computational Engineering, Finance, and Science (cs.CE)
subject: FOS: Computer and information sciences

description: This research proposes an effective vertical clustering strategy of 3D data in an elliptical helical shape based on 2D geometry. The clustering object is an elliptical cross-sectioned metal pipe which is been bended in to an elliptical helical shape which is used in wearable muscle support designing for welfare industry. The aim of this proposed method is to maximize the vertical clustering (vertical partitioning) ability of surface data in order to run the product evaluation process addressed in research [2]. The experiment results prove that the proposed method outperforms the existing threshold no of clusters that preserves the vertical shape than applying the conventional 3D data. This research also proposes a new product testing strategy that provides the flexibility in computer aided testing by not restricting the sequence depending measurements which apply weight on measuring process. The clustering algorithms used for the experiments in this research are self-organizing map (SOM) and K-medoids.
$*$-Logarithm for Slice Regular Functions
Creators: name: Altavilla, Amedeo
name: de Fabritiis, Chiara
Publisher: name: arXiv
Year: 2021
Subjects: subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: Primary 30G35, secondary 30C25, 32A30, 33B10

description: In this paper, we study the (possible) solutions of the equation $\exp_{*}(f)=g$, where $g$ is a slice regular never vanishing function on a circular domain of the quaternions $\mathbb{H}$ and $\exp_{*}$ is the natural generalization of the usual exponential to the algebra of slice regular functions. Any function $f$ which satisfies $\exp_{*}(f)=g$ is called a $*$-logarithm of $g$. We provide necessary and sufficient conditions, expressed in terms of the zero set of the ``vector'' part $g_{v}$ of $g$, for the existence of a $*$-logarithm of $g$, under a natural topological condition on the domain $Ω$. By the way, we prove an existence result if $g_{v}$ has no non-real isolated zeroes; we are also able to give a comprehensive approach to deal with more general cases. We are thus able to obtain an existence result when the non-real isolated zeroes of $g_{v}$ are finite, the domain is either the unit ball, or $\mathbb{H}$, or $\mathbb{D}$ and a further condition on the ``real part'' $g_{0}$ of $g$ is satisfied (see Theorem 6.19 for a precise statement). We also find some unexpected uniqueness results, again related to the zero set of $g_{v}$, in sharp contrast with the complex case. A number of examples are given throughout the paper in order to show the sharpness of the required conditions.
description: 27 pages, 4 figures. Published in Rendiconti Lincei Matematica e Applicazioni
Experimental investigation of the optical spin selection rules in bulk Si and Ge/Si quantum dots
Creators: name: Sircar, N.
name: Bougeard, D.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We study the relationship between the circular polarization of photoluminescence and the magnetic field-induced spin-polarization of the recombining charge carriers in bulk Si and Ge/Si quantum dots. First, we quantitatively compare experimental results on the degree of circular polarization of photons resulting from phonon-assisted radiative transitions in intrinsic and doped bulk Si with calculations which we adapt from recently predicted spin-dependent phonon-assisted transition probabilities in Si. The excellent agreement of our experiments and calculations quantitatively verifies these spin-dependent transition probabilities and extends their validity to weak magnetic fields. Such magnetic fields can induce a luminescence polarization of up to 3%/T. We then investigate phononless transitions in Ge/Si quantum dots as well as in degenerately doped Si. Our experiments systematically show that the sign of the degree of circular polarization of luminescence resulting from phononless transitions is opposite to the one associated with phonon-assisted transitions in Si and with phononless transitions in direct band gap semiconductors. This observation implies qualitatively different spin-dependent selection rules for phononless transitions, which seem to be related to the confined character of the electron wave function.
description: accepted for publication in Physical Review B rapid communication
Visible near-diffraction limited lucky imaging with full-sky laser assisted adaptive optics
Creators: name: Basden, Alastair
Publisher: name: arXiv
Year: 2014
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: FOS: Physical sciences

description: Both lucky imaging techniques and adaptive optics require natural guide stars, limiting sky coverage, even when laser guide stars are used. Lucky imaging techniques become less successful on larger telescopes unless adaptive optics is used, as the fraction of images obtained with well behaved turbulence across the whole telescope pupil becomes vanishingly small. Here, we introduce a technique combining lucky imaging techniques with tomographic laser guide star adaptive optics systems on large telescopes. This technique does not require any natural guide star for the adaptive optics, and hence offers full sky-coverage adaptive optics correction. In addition, we introduce a new method for lucky image selection based on residual wavefront phase measurements from the adaptive optics wavefront sensors. We perform Monte-Carlo modelling of this technique, and demonstrate I-band Strehl ratios of up to 35% in 0.7~arcsecond mean seeing conditions with 0.5~m deformable mirror pitch and full adaptive optics sky-coverage. We show that this technique is suitable for use with lucky imaging reference stars as faint as Magnitude 18, and fainter if more advanced image selection and centring techniques are used.
description: Accepted for publication in MNRAS
An XAI Approach to Deep Learning Models in the Detection of DCIS
Creators: name: La Ferla, Michele
name: Montebello, Matthew
name: Seychell, Dylan
Publisher: name: arXiv
Year: 2021
Subjects: subject: Image and Video Processing (eess.IV)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences

description: The results showed that XAI could indeed be used as a proof of concept to begin discussions on the implementation of assistive AI systems within the clinical community.
description: 12 pages, 5 figures
The spotty donor star in the X-ray transient Cen X-4
Creators: name: Shahbaz, T.
name: Watson, C. A.
name: Dhillon, V. S.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We accurately determine the fundamental system parameters of the neutron-star X-ray transient Cen X-4 solely using phase-resolved high-resolution UVES spectroscopy. We first determine the radial-velocity curve of the secondary star and then model the shape of the phase-resolved absorption line profiles using an X-ray binary model. The model computes the exact rotationally broadened phase-resolved spectrum and does not depend on assumptions about the rotation profile, limb-darkening coefficients and the effects of contamination from an accretion disk. We determine the secondary star-to-neutron star binary mass ratio to be 0.1755+/-0.0025, which is an order of magnitude more accurate than previous estimates. We also constrain the inclination angle to be 32 (+8; -2) degrees, Combining these values with the results of the radial velocity study gives a neutron star mass of 1.94 (+0.37; -0.85) Msun consistent with previous estimates. Finally, we perform the first Roche tomography reconstruction of the secondary star in an X-ray binary. The tomogram reveals surface inhomogeneities that are due to the presence of cool starspots. A large cool polar spot, similar to that seen in Doppler images of rapidly-rotating isolated stars is present on the Northern hemisphere of the K7 secondary star and we estimate that about 4 per cent of the total surface area of the donor star is covered with spots. This evidence for starspots supports the idea that magnetic braking plays an important role in the evolution of low-mass X-ray binaries.
description: 10 pages, 8 figures accepted for publication in MNRAS
Elliptic Ruijsenaars difference operators, symmetric polynomials, and Wess-Zumino-Witten fusion rings
Creators: name: van Diejen, Jan Felipe
name: Görbe, Tamás
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Algebra (math.QA)
subject: Mathematical Physics (math-ph)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 05E05 (Primary) 05E10, 33D52, 81T40, 81T45, 81Q80 (Secondary)

description: The fusion ring for $\widehat{\mathfrak{su}}(n)_m$ Wess-Zumino-Witten conformal field theories is known to be isomorphic to a factor ring of the ring of symmetric polynomials presented by Schur polynomials. We introduce a deformation of this factor ring associated with eigenpolynomials for the elliptic Ruijsenaars difference operators. The corresponding Littlewood-Richardson coefficients are governed by a Pieri rule stemming from the eigenvalue equation. The orthogonality of the eigenbasis gives rise to an analog of the Verlinde formula. In the trigonometric limit, our construction recovers the refined $\widehat{\mathfrak{su}}(n)_m$ Wess-Zumino-Witten fusion ring associated with the Macdonald polynomials.
description: 21 pages
Geometric spectra and commensurability
Creators: name: McReynolds, D. B.
Publisher: name: arXiv
Year: 2014
Subjects: subject: Geometric Topology (math.GT)
subject: FOS: Mathematics

description: The work of Reid, Chinburg--Hamilton--Long--Reid, Prasad--Rapinchuk, and the author with Reid have demonstrated that geodesics or totally geodesic submanifolds can sometimes be used to determine the commensurability class of an arithmetic manifold. The main results of this article show that generalizations of these results to other arithmetic manifolds will require a wide range of data. Specifically, we prove that certain incommensurable arithmetic manifolds arising from the semisimple Lie groups of the form $(\SL(d,\R))^r \times (\SL(d,\C))^s$ have the same commensurability classes of totally geodesic submanifolds coming from a fixed field. This construction is algebraic and shows the failure of determining, in general, a central simple algebra from subalgebras over a fixed field. This, in turn, can be viewed in terms of forms of $\SL_d$ and the failure of determining the form via certain classes of algebraic subgroups.
description: to appear in Cand. Jour. Math
The Statistical Physics of Athermal Materials
Creators: name: Bi, Dapeng
name: Henkes, Silke
name: Daniels, Karen E.
name: Chakraborty, Bulbul
Publisher: name: arXiv
Year: 2014
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: At the core of equilibrium statistical mechanics lies the notion of statistical ensembles: a collection of microstates, each occurring with a given a priori probability that depends only on a few macroscopic parameters such as temperature, pressure, volume, and energy. In this review article, we discuss recent advances in establishing statistical ensembles for athermal materials. The broad class of granular and particulate materials is immune from the effects of thermal fluctuations because the constituents are macroscopic. In addition, interactions between grains are frictional and dissipative, which invalidates the fundamental postulates of equilibrium statistical mechanics. However, granular materials exhibit distributions of microscopic quantities that are reproducible and often depend on only a few macroscopic parameters. We explore the history of statistical ensemble ideas in the context of granular materials, clarify the nature of such ensembles and their foundational principles, highlight advances in testing key ideas, and discuss applications of ensembles to analyze the collective behavior of granular materials.
Towards Cloud Computing: A SWOT Analysis on its Adoption in SMEs
Creators: name: Ghaffari, Kimia
name: Delgosha, Mohammad Soltani
name: Abdolvand, Neda
Publisher: name: arXiv
Year: 2014
Subjects: subject: Distributed, Parallel, and Cluster Computing (cs.DC)
subject: FOS: Computer and information sciences

description: Over the past few years, emergence of cloud computing has notably made an evolution in the IT industry by putting forward an "everything as a service" idea .Cloud Computing is of growing interest to companies throughout the world, but there are many barriers associated with its adoption which should be eliminated. This paper aims to investigate Cloud Computing and discusses the drivers and inhibitors of its adoption. Moreover, an attempt has been made to identify the key stakeholders of Cloud Computing and outline the current security challenges. A SWOT analysis which consists of strengths, weaknesses, opportunities and threats has also carried out in which Cloud Computing adoption for SMEs (Small and Medium-sized Enterprises) is evaluated. Finally, the paper concludes with some further research areas in the field of Cloud Computing.
Proof-of-Stake Mining Games with Perfect Randomness
Creators: name: Ferreira, Matheus V. X.
name: Weinberg, S. Matthew
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Science and Game Theory (cs.GT)
subject: Cryptography and Security (cs.CR)
subject: Theoretical Economics (econ.TH)
subject: FOS: Computer and information sciences
subject: FOS: Economics and business

description: Proof-of-Stake blockchains based on a longest-chain consensus protocol are an attractive energy-friendly alternative to the Proof-of-Work paradigm. However, formal barriers to "getting the incentives right" were recently discovered, driven by the desire to use the blockchain itself as a source of pseudorandomness \cite{brown2019formal}. We consider instead a longest-chain Proof-of-Stake protocol with perfect, trusted, external randomness (e.g. a randomness beacon). We produce two main results. First, we show that a strategic miner can strictly outperform an honest miner with just $32.5\%$ of the total stake. Note that a miner of this size {\em cannot} outperform an honest miner in the Proof-of-Work model. This establishes that even with access to a perfect randomness beacon, incentives in Proof-of-Work and Proof-of-Stake longest-chain protocols are fundamentally different. Second, we prove that a strategic miner cannot outperform an honest miner with $30.8\%$ of the total stake. This means that, while not quite as secure as the Proof-of-Work regime, desirable incentive properties of Proof-of-Work longest-chain protocols can be approximately recovered via Proof-of-Stake with a perfect randomness beacon. The space of possible strategies in a Proof-of-Stake mining game is {\em significantly} richer than in a Proof-of-Work game. Our main technical contribution is a characterization of potentially optimal strategies for a strategic miner, and in particular, a proof that the corresponding infinite-state MDP admits an optimal strategy that is positive recurrent.
description: 79 Pages, ACM EC 2021
Uncertainty Relations for the Relativistic Jackiw-Nair Anyon: A First Principles Derivation
Creators: name: Majhi, Joydeep
name: Ghosh, Subir
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Other Condensed Matter (cond-mat.other)
subject: Mathematical Physics (math-ph)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In this paper we have explicitly computed the $position-position$ and $position-momentum$ (Heisenberg) Uncertainty Relations for the model of relativistic particles with arbitrary spin, proposed by Jackiw and Nair ref.[1] as a model for Anyon, in a purely quantum mechanical framework. This supports (via Schwarz inequality) the conjecture that anyons live in a 2-dimensional \textit{noncommutative} space. We have computed the non-trivial uncertainty relation between anyon coordinates, ${\sqrt{Δx^2Δy^2}}=\hbar\barΘ_{xy}$, using the recently constructed anyon wave function ref.[6], in the framework of ref.[7]. We also compute the Heisenberg (position-momentum) uncertainty relation for anyons. Lastly we show that the identical \textit{formalism} when applied to electrons, yield a trivial position uncertainty relation, consistent with their living in a 3-dimensional commutative space.
description: 7 pages, 5 figures; title changed, change in presentation, no channge in final results and conclusions, accepted in EPL
Towards the Framework of Information Security
Creators: name: Kahanwal, Dr. Brijender
name: Singh, Dr. Tejinder Pal
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences

description: Todays modern society is extremely dependent on computer based information systems. Many of the organizations would simply not be able to function properly without services provided by these systems, just like financing organizations. Although interruption might decrease the efficiency of an organization, theft or unintentional disclosure of entrusted private data could have more serious consequences, such as legal actions as well as loss of business due to lack of trust from potential users. This dependence on information systems has lead to a need for securing these systems and this in turn has created a need for knowing how secure they are. The introduction of the information society has changed how people interact with government agencies. Government agencies are now encouraged to uphold a 24-hour electronic service to the citizens. The introduction of government services on the Internet is meant to facilitate communication with agencies, decrease service times and to lessen the amount of papers that needs to be processed. The increased connectivity to the Internet results in a rising demand for information security in these systems. In this article, we have discussed about many file data breaches in the past and current history and they are going to increase day by day as the reports by DataLossDB (Open Security Foundation) organization, a non-profit organization in US.
description: 4 pages, 4 figures, 1 table
First BGG operators via homogeneous examples
Creators: name: Gregorovič, Jan
name: Zalabová, Lenka
Publisher: name: arXiv
Year: 2021
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 53C07, 53C30, 58J70, 53A40 (Primary) 53C15, 58J10, 58J60, 58A30 (Secondary)

description: We review the theory of first BGG operators and study how to approach them and find their solution on homogeneous geometries. We provide many new examples of parabolic geometries that admit solutions of first BGG operators with many interesting properties and interpretations.
description: 50 pp, comments welcome
Abundance Patterns in the Interstellar Medium of Early-type Galaxies Observed with Suzaku
Creators: name: Konami, Saori
name: Matsushita, Kyoko
name: Nagino, Ryo
name: Tamagawa, Toru
Publisher: name: arXiv
Year: 2014
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We have analyzed 17 early-type galaxies, 13 ellipticals and 4 S0's, observed with Suzaku, and investigated metal abundances (O, Mg, Si, and Fe) and abundance ratios (O/Fe, Mg/Fe, and Si/Fe) in the interstellar medium (ISM). The emission from each on-source region, which is 4 times effective radius, r_e, is reproduced with one- or two- temperature thermal plasma models as well as a multi-temperature model, using APEC plasma code v2.0.1. The multi-temperature model gave almost the same abundances and abundance ratios with the 1T or 2T models. The weighted averages of the O, Mg, Si, and Fe abundances of all the sample galaxies derived from the multi-temperature model fits are 0.83+-0.04, 0.93+-0.03, 0.80+-0.02, and 0.80+-0.02 solar, respectively, in solar units according to the solar abundance table by Lodders (2003). These abundances show no significant dependence on the morphology and environment. The systematic differences in the derived metal abundances between the version 2.0.1 and 1.3.1 of APEC plasma codes were investigated. The derived O and Mg abundances in the ISM agree with the stellar metallicity within a aperture with a radius of one r_e derived from optical spectroscopy. From these results, we discuss the past and present SN Ia rates and star formation histories in early-type galaxies.
description: 32 pages, 23 figures, accepted for publication in ApJ
Induced subgraphs and tree decompositions II. Toward walls and their line graphs in graphs of bounded degree
Creators: name: Abrishami, Tara
name: Chudnovsky, Maria
name: Dibek, Cemil
name: Hajebi, Sepehr
name: Rzążewski, Paweł
name: Spirkl, Sophie
name: Vušković, Kristina
Publisher: name: arXiv
Year: 2021
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics

description: This paper is motivated by the following question: what are the unavoidable induced subgraphs of graphs with large treewidth? Aboulker et al. made a conjecture which answers this question in graphs of bounded maximum degree, asserting that for all $k$ and $Δ$, every graph with maximum degree at most $Δ$ and sufficiently large treewidth contains either a subdivision of the $(k\times k)$-wall or the line graph of a subdivision of the $(k\times k)$-wall as an induced subgraph. We prove two theorems supporting this conjecture, as follows. 1. For $t\geq 2$, a $t$-theta is a graph consisting of two nonadjacent vertices and three internally disjoint paths between them, each of length at least $t$. A $t$-pyramid is a graph consisting of a vertex $v$, a triangle $B$ disjoint from $v$ and three paths starting at $v$ and disjoint otherwise, each joining $v$ to a vertex of $B$, and each of length at least $t$. We prove that for all $k,t$ and $Δ$, every graph with maximum degree at most $Δ$ and sufficiently large treewidth contains either a $t$-theta, or a $t$-pyramid, or the line graph of a subdivision of the $(k\times k)$-wall as an induced subgraph. This affirmatively answers a question of Pilipczuk et al. asking whether every graph of bounded maximum degree and sufficiently large treewidth contains either a theta or a triangle as an induced subgraph (where a theta means a $t$-theta for some $t\geq 2$). 2. A subcubic subdivided caterpillar is a tree of maximum degree at most three whose all vertices of degree three lie on a path. We prove that for every $Δ$ and subcubic subdivided caterpillar $T$, every graph with maximum degree at most $Δ$ and sufficiently large treewidth contains either a subdivision of $T$ or the line graph of a subdivision of $T$ as an induced subgraph.
description: Accepted manuscript; see DOI for journal version
Zonal reconstruction of daylighting
Creators: name: Grobe, Lars Oliver
name: Noback, Andreas
name: Wasilewski, Stephen
name: Mächler, Claudia
name: Lang, Franziska
Publisher: name: Zenodo
Year: 2022
Subjects: daylighting
daylight metrics
raytraverse
Ostia

description: The python module phos4dtool implements the computation of a wide range of daylight metrics that are considered to indicate affordances in the historical context of the assessed sites by raytraverse, employing the lighting simulation software Radiance as a back-end. The application of phos4dtool shall be demonstrated for the case of a residential complex in Ostia. Integration with a Geographical information System (GIS) is suggested to allow overlaying the simulation results with other, spatially organised archaeological research data such as site plans and the location of finds indicating activ- ities. It is intended to cross the barriers between those performing daylight simulation and developing daylight metrics and those correlating them to other sources. This shall foster interdisciplinary col- laboration in the research of historic lighting.
description: This research was supported by the German Federal Ministry of Education and Research as part the project "ΦΩΣ 4D – Werkzeug zur Affordanz-basierten Tageslichtanalyse in antiken Häusern mittels Simulation".
Complements of hypersurfaces, variation maps and minimal models of arrangements
Creators: name: Tibar, Mihai
Publisher: name: arXiv
Year: 2014
Subjects: subject: Algebraic Geometry (math.AG)
subject: Complex Variables (math.CV)
subject: FOS: Mathematics

description: We prove the minimality of the CW-complex structure for complements of hyperplane arrangements in $\mathbb C^n$ by using the theory of Lefschetz pencils and results on the variation maps within a pencil of hyperplanes. This also provides a method to compute the Betti numbers of complements of arrangements via global polar invariants.
Improvement of a Prediction Model for Heart Failure Survival through Explainable Artificial Intelligence
Creators: name: Moreno-Sanchez, Pedro A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Cardiovascular diseases and their associated disorder of heart failure are one of the major death causes globally, being a priority for doctors to detect and predict its onset and medical consequences. Artificial Intelligence (AI) allows doctors to discover clinical indicators and enhance their diagnosis and treatments. Specifically, explainable AI offers tools to improve the clinical prediction models that experience poor interpretability of their results. This work presents an explainability analysis and evaluation of a prediction model for heart failure survival by using a dataset that comprises 299 patients who suffered heart failure. The model employs a data workflow pipeline able to select the best ensemble tree algorithm as well as the best feature selection technique. Moreover, different post-hoc techniques have been used for the explainability analysis of the model. The paper's main contribution is an explainability-driven approach to select the best prediction model for HF survival based on an accuracy-explainability balance. Therefore, the most balanced explainable prediction model implements an Extra Trees classifier over 5 selected features (follow-up time, serum creatinine, ejection fraction, age and diabetes) out of 12, achieving a balanced-accuracy of 85.1% and 79.5% with cross-validation and new unseen data respectively. The follow-up time is the most influencing feature followed by serum-creatinine and ejection-fraction. The explainable prediction model for HF survival presented in this paper would improve a further adoption of clinical prediction models by providing doctors with intuitions to better understand the reasoning of, usually, black-box AI clinical solutions, and make more reasonable and data-driven decisions.
description: arXiv admin note: text overlap with arXiv:2105.10368