cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Η Εξέλιξη του Οικονομικού Δικτύου του Χρηματιστηρίου Αξιών Αθηνών από το 2007 ως το 2011
Creators: name: Χατζοπούλου, Αικατερίνη Πολύβιου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: Οικονομικό δίκτυο
Αμοιβαία πληροφορία
Καθολικά μέτρα
Economic network
Mutual information
Global indicies

description: Για σχεδόν δυο δεκαετίες, εμπειρικά και θεωρητικά αποτελέσματα της Θεωρίας Δικτύων χρησιμοποιούνται στην ανάλυση Οικονομικών Δικτύων. Στην παρούσα διατριβή μελετήθηκε η εξέλιξη του Οικονομικού Δικτύου του Χρηματιστηρίου Αξιών Αθηνών από το 2007 ως το 2011, με χρήση χρονικών παραθύρων διάρκειας 6 μηνών χωρίς επικάλυψη. Για κάθε παράθυρο δημιουργήθηκε ένα πλήρες σταθμισμένο δίκτυο στο οποίο κόμβοι είναι οι μετοχές. Για την ακμή μεταξύ δυο κόμβων (ζεύγος μετοχών), υπολογίστηκε η αμοιβαία πληροφορία μεταξύ των χρονοσειρών των αποδόσεων (returns) με τη χρήση κατάλληλου για το πλήθος των παρατηρήσεων, εκτιμητή της εντροπίας του Shannon. Στη συνέχεια οι τιμές της αμοιβαίας πληροφορίας μετασχηματίστηκαν σε τιμές μιας συνάρτησης απόστασης. Με την οποία σταθμίστηκαν τα δίκτυα. Οι τεχνικές που χρησιμοποιήθηκαν για τη μελέτη της εξέλιξης των παραπάνω δικτύων στηρίχθηκαν στη δημιουργία του Ελαχίστου Δένδρου Ζεύξης (MST), του Επίπεδου Μέγιστα Φιλτραρισμένου Γραφήματος (PMFG), την εύρεση των κοινοτήτων (Community Structure), τον υπολογισμό των μέτρων κεντρικότητας (Centrality Measures), των καθολικών μέτρων (global indices) του συντελεστή assortativity και του συντελεστή ενδοκατηγορικής συσχέτισης (ICC) ενώ παράλληλα δόθηκε η ερμηνεία των αποτελεσμάτων μέσα από οικονομικά γεγονότα της επιλεγμένης χρονικής περιόδου. Μέρος της παρούσας διπλωματικής παρουσιάστηκε στο 29ο Πανελλήνιο Συνέδριο Στατιστικής, που πραγματοποιήθηκε στη Θεσσαλονίκη και τη Νάουσα από τις 4 ως τις 7 Μαΐου το 2016.
description: For most than a decade results of Network Theory are being used to analyze the evolution of Economics Networks. This thesis studied the evolution of the Financial Network of Athens Stock Exchanges from 2007 until 2011. We have divided the time series into time windows with width of six months without overlapping. In each window, each index was a vertex and each edge connecting two vertices was marked by the value of a distance function made by the Mutual Information obtained from the time series of logarithmic returns of stocks. For this calculation we used an appropriate Entropy estimator. Then, we transformed this similarity measure into a distance function created a series of Complete Weighted Networks. The techniques used to analyze these networks were based on the creation and development of Minimum Spanning Tree (MST), Planar Maximally Filtered Graph (PMFG), the calculation of centrality measures, global indices, intraclass correlation coefficient (consistency), finding the community structure, identifying cliques. The results were interpreted based on specific economic events and relations between the stocks that took place during this period. Part of this thesis was presented at the 29th Panhellenic Conference of Statistics.
Vector Cooper Pairs and Coherent-Population-Trapping-like States in Ensemble of Interacting Fermions
Creators: name: Taichenachev, A. V.
name: Yudin, V. I.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Using the standard Hamiltonian of the BCS theory, we show that in an ensemble of interacting fermions with the spin 1/2 there exist coherent states $|NC>$, which nullify the Hamiltonian of the interparticle interaction (scattering). These states have an analogy with the well-known in quantum optics the coherent population trapping (CPT) effect. The structure of these CPT-like states corresponds to Cooper pairs with the total spin $S$=1. The found states have a huge degree of degeneracy and carry a macroscopic magnetic moment, that allows us to construct a new model of the magnetism connected with the delocalized electrons in metals (conductors). A principal possibility to apply the obtained results to the superfluid $^3$He is also demonstrated.
description: revtex, 12 pages, 2 figures
Surface Gravity of Rotating Dumbbell Shapes
Creators: name: Lam, Wai-Ting
name: Gidea, Marian
name: Zypman, Fredy R
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Mathematical Physics (math-ph)
subject: Dynamical Systems (math.DS)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We investigate the problem of determining the shape of a rotating celestial object - e.g., a comet or an asteroid - under its own gravitational field. More specifically, we consider an object symmetric with respect to one axis - such as a dumbbell - that rotates around a second axis perpendicular to the symmetry axis. We assume that the object can be modeled as an incompressible fluid of constant mass density, which is regarded as a first approximation of an aggregate of particles. In the literature, the gravitational field of a body is often described as a multipolar expansion involving spherical coordinates (Kaula, 1966). In this work we describe the shape in terms of cylindrical coordinates, which are most naturally adapted to the symmetry of the body, and we express the gravitational potential generated by the rotating body as a simple formula in terms of elliptic integrals. An equilibrium shape occurs when the gravitational potential energy and the rotational kinetic energy at the surface of the body balance each other out. Such an equilibrium shape can be derived as a solution of an optimization problem, which can be found via the variational method. We give an example where we apply this method to a two-parameter family of dumbbell shapes, and find approximate numerical solutions to the corresponding optimization problem.
Η διάσταση του φύλου στη διεύθυνση της σχολικής μονάδας και η επίδρασή του στην αναβάθμιση του έργου της: απόψεις μαθητών/τριών και εκπαιδευτικών λυκείου
Creators: name: Φουρλάτου, Ανθούλα Αντωνίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: διάσταση του φύλου
διεύθυνση σχολικής μονάδας
μαθητές/τριες
gender dimension
school administration
students

description: Το θέμα που πραγματεύεται η παρούσα θεωρητική και εμπειρική μελέτη είναι η ανάληψη της διεύθυνσης των σχολικών μονάδων από γυναίκες εκπαιδευτικούς και, κατ’ επέκταση, το πόσο το φύλο επηρεάζει τις απόψεις των εμπλεκομένων με τη σχολική μονάδα μελών σχετικά με τη διαχείρισή της. Στο πλαίσιο της εμπειρικής διερεύνησης του θέματος διεξήχθησαν ημι-δομημένες συνεντεύξεις με οκτώ εκπαιδευτικούς και δέκα μαθητές/τριες σχολείων δευτεροβάθμιας εκπαίδευσης του Νομού Θεσσαλονίκης. Από την ποιοτική ανάλυση των συνεντεύξεων δημιουργήθηκαν τέσσερις μεγάλες θεματικές κατηγορίες: α) Ο ρόλος του/της διευθυντή/ντριας των σχολικών μονάδων της δευτεροβάθμιας εκπαίδευσης β) η διάσταση του φύλου στην εκπαιδευτική ηγεσία και στυλ διοίκησης, γ) η διάσταση του φύλου στη δημιουργία θετικού σχολικού κλίματος και δ) οι επιλογές δράσης των διευθυντών/ντριών για την αναβάθμιση των σχολικών μονάδων. Η έρευνα ανέδειξε τις επιδράσεις που έχει αυτή η διάσταση στην αποτελεσματικότητα της σχολικής μονάδας, κι επιπλέον συνέβαλε στην προβολή των αντιλήψεων, στάσεων και απόψεων τόσο των εκπαιδευτικών όσο και των μαθητών/τριών λυκείου όσον αφορά το φύλο και τη διοίκηση.
description: The subject of the present theoretical and empirical study is the management of schools by female teachers and, therefore, how gender affects the views of those involved in the administration of schools. Within the empirical research were conducted semi-structured interviews with eight teachers and ten students of secondary schools in Thessaloniki. During the qualitative analysis of the interviews were created four major thematic categories: a) The role of the school headmaster in secondary education b) the gender dimension in educational leadership and management style, c) the gender dimension to a positive school climate and d) the options for action available to the headmasters in order to upgrade the schools. The survey highlighted the impacts that this dimension has on the effectiveness of the school unit, and further contributed to the promotion of perceptions, attitudes and opinions of both high school teachers and students regarding the issue of gender and administration.
Spectrum of electronic excitations due to the adsorption of atoms on metal surfaces
Creators: name: Mizielinski, M. S.
name: Bird, D. M.
name: Persson, M.
name: Holloway, S.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The time-dependent, mean-field Newns-Anderson model for a spin-polarised adsorbate approaching a metallic surface is solved in the wide-band limit. Equations for the time-evolution of the electronic structure of the adsorbate-metal system are derived and the spectrum of electronic excitations is found. The behaviour of the model is demonstrated for a set of physically reasonable parameters.
description: 20 pages, 5 figures
Partition functions and elliptic genera from supergravity
Creators: name: Kraus, Per
name: Larsen, Finn
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We develop the spacetime aspects of the computation of partition functions for string/M-theory on AdS(3) xM. Subleading corrections to the semi-classical result are included systematically, laying the groundwork for comparison with CFT partition functions via the AdS(3)/CFT(2) correspondence. This leads to a better understanding of the "Farey tail" expansion of Dijkgraaf et. al. from the point of view of bulk physics. Besides clarifying various issues, we also extend the analysis to the N=2 setting with higher derivative effects included.
description: 34 pages
D2.1 User Requirements Specification
Creators: name: Filip, Aleš,; Olík, Filip; Neri, Alessandro; Salvitti, Maurizio; Xefteris, Panagiotis; Dionisio, Cesare; Salvatori, Pietro; Capua, Roberto; Gattuso, Luca; Innoccente, Manuele; Crespillo, Omar Garcia; Kutik, Ondrej; Loupis, Michael
Publisher: name: Zenodo
Year: 2020
Subjects: Multimodal
AIMN

description: This is part of H2020 HELMET Project
Planar Decompositions and the Crossing Number of Graphs with an Excluded Minor
Creators: name: Wood, David R.
name: Telle, Jan Arne
Publisher: name: arXiv
Year: 2006
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05C62 (graph representations), 05C10 (topological graph theory), 05C83 (graph minors)

description: Tree decompositions of graphs are of fundamental importance in structural and algorithmic graph theory. Planar decompositions generalise tree decompositions by allowing an arbitrary planar graph to index the decomposition. We prove that every graph that excludes a fixed graph as a minor has a planar decomposition with bounded width and a linear number of bags. The crossing number of a graph is the minimum number of crossings in a drawing of the graph in the plane. We prove that planar decompositions are intimately related to the crossing number. In particular, a graph with bounded degree has linear crossing number if and only if it has a planar decomposition with bounded width and a linear number of bags. It follows from the above result about planar decompositions that every graph with bounded degree and an excluded minor has linear crossing number. Analogous results are proved for the convex and rectilinear crossing numbers. In particular, every graph with bounded degree and bounded tree-width has linear convex crossing number, and every $K_{3,3}$-minor-free graph with bounded degree has linear rectilinear crossing number.
description: An extended abstract of this paper was published in the Proceedings of the Graph Drawing Conference (GD 2006), Lecture Notes in Computer Science 4372:150-161, Springer, 2007
Παθητικότητα και Ευστάθεια Εισόδου Καταστάσεων, με Εφαρμογή σε Ρομποτικούς Βραχίονες
Creators: name: Μόσχος, Ιωάννης Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Παθητικότητα
Ευστάθεια Εισόδου Καταστάσεων
Σχέση παθητικότητας και Ευστάθειας Εισόδου Καταστάσεων
Passivity
Input to State Stability
Connection Between Passivity and Input to State Stability

description: Στην παρούσα διπλωματική εργασία μελετάμε τις ιδιότητες της απώλειας ενέργειας (dissipativity), της παθητικότητας και ευστάθειας εισόδου καταστάσεων καθώς και της ασυμπτωτικής ευστάθειας σε μη γραμμικά συστήματα, με εφαρμογή σε ρομποτικούς βραχίονες και στον έλεγχο τους από γραμμικούς PD ελεγκτές και μη γραμμικές μορφές του. Πρώτον, γίνεται μια σύντομη αναφορά των δυναμικών εξισώσεων Euler-Lagrange και της ευστάθειας Lyapunov για τους ρομποτικούς βραχίονες. Στη συνέχεια, παρουσιάζουμε τις έννοιες των συστημάτων με απώλειες ενέργειας και των παθητικών συστημάτων και την σύνδεση που έχουν με την ευστάθεια Lyapunov. Δεύτερον, προχωράμε στην μελέτη της ευστάθειας εισόδου καταστάσεων για ρομποτικούς βραχίονες η οποία περιγράφεται από διαφορίσιμες ανισότητες απώλειας ενέργειας. Εισάγουμε την έννοια της ευστάθειας εισόδου καταστάσεων και τις ειδικές μορφές της ευστάθειας εξόδου και εισόδου-εξόδου καταστάσεων για μη γραμμικά συστήματα. Επιπλέον, παραθέτουμε την ολοκληρωτική ευστάθεια εισόδου καταστάσεων, καθώς μας επιτρέπει να εφαρμόσουμε σε ασταθή συστήματα εισόδους που τα καθιστούν ευσταθή, δίνοντας παραδείγματα με ρομποτικούς βραχίονες. Τέλος, εξετάζουμε την σύνδεση της ευστάθειας Lyapunov και παθητικότητας με την ευστάθεια εισόδου καταστάσεων για ρομποτικούς βραχίονες
description: In the present thesis we examine the properties of dissipativity, passivity and input-to-state stability, as well as the asymptotic stability in nonlinear systems, with application in robot manipulators and their control using the linear PD controller and some nonlinear forms of the controller. Firstly, we briefly analyze the dynamical equations Euler-Lagrange and Lyapunov stability for robot manipulators. Afterwards, we present the concept of dissipative and passive systems and their connection with Lyapunov stability. Secondly, we proceed in the study of input-to-state stability for robot manipulators, which is described with differential dissipation inequalities. We introduce the concept of input-to-state stability and the special cases of input-output to state and output-to-state stability for nonlinear systems. In addition, we state the integral input-to-state stability, which allows us to apply inputs in unstable systems to render them stable, with examples in robot manipulators. Finally, we exam the connection between the Lyapunov stability and input-to-state stability for robot manipulators
Homology and Derived Series of Groups II: Dwyer's Theorem
Creators: name: Cochran, Tim D.
name: Harvey, Shelly
Publisher: name: arXiv
Year: 2006
Subjects: subject: Geometric Topology (math.GT)
subject: Algebraic Topology (math.AT)
subject: Group Theory (math.GR)
subject: FOS: Mathematics
subject: 57M07 (Primary); 20J06, 55P60 (Secondary)

description: We give new information about the relationship between the low-dimensional homology of a group and its derived series. This yields information about how the low-dimensional homology of a topological space constrains its fundamental group. Applications are given to detecting when a set of elements of a group generates a subgroup ``large enough'' to map onto a non-abelian free solvable group, and to concordance and grope cobordism of links. We also greatly generalize several key homological results employed in recent work of Cochran-Orr-Teichner, in the context of classical knot concordance. In 1963 J. Stallings established a strong relationship between the low-dimensional homology of a group and its lower central series quotients. In 1975 W. Dwyer extended Stallings' theorem by weakening the hypothesis on the second homology groups. The naive analogues of these theorems for the derived series are false. In 2003 the second author introduced a new characteristic series, associated to the derived series, called the torsion-free derived series. The authors previously established a precise analogue, for the torsion-free derived series, of Stallings' theorem. Here our main result is the analogue of Dwyer's theorem for the torsion-free derived series. We also prove a version of Dwyer's theorem for the rational lower central series. We apply these to give new results on the Cochran-Orr-Teichner filtration of the classical link concordance group.
description: 26 pages. In this version, we have included a new proof of part of the main theorem. The new proof is somewhat simpler and stays entirely in the world of group homology and homological algebra rather than using Eilenberg-Mac Lane spaces. Other minor corrections. This is the final version to appear in Geometry & Topology
An alternative to proportional-integral and proportional-integral-derivative regulators: Intelligent proportional-derivative regulators
Creators: name: Fliess, Michel
name: Join, Cédric
Publisher: name: arXiv
Year: 2021
Subjects: subject: Systems and Control (eess.SY)
subject: Optimization and Control (math.OC)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Mathematics

description: This paper suggests to replace PIs and PIDs, which play a key role in control engineering, by intelligent Proportional-Derivative feedback loops, or iPDs, which are derived from model-free control. This standpoint is enhanced by a laboratory experiment.
description: Accepted in "International Journal of Robust and Nonlinear Control"
Reliability based design of light gauge timber connectors
Creators: name: Kazemi, Masoud Reza
Publisher: name: University of British Columbia
Year: 2009

description: Joist hangers are one of the most common types of mechanical connectors used in today’s wood construction industry. Yet, testing agencies and design codes do not have a proper testing procedure and design guidelines to predict the capacity of these connectors. The exisiting design guidelines are not compatible with the current Limit States Design Code in Canada. Various issues related to the existing joist hanger test procedures were studied to identify the important criteria for possible adaptation to current Canadian design standards, while maintaining the link between testing rules and common construction practice. A list of recommendations and notes were made to act as guidelines for future modification or subsequent revision of these standards. As the main focus of this study, an analytical model which predicts the serviceability and ultimate resistances of light gauge joist hangers was developed, based on a wide-ranging series of experimental results. This was achieved by adapting analytical procedures to reflect observed failure modes in tested joist hanger assemblies, and ultimately through calibration against experimental test results. This model is suitable for load capacity calculations or for reliability studies of light gauge structural timber connectors.
The Canonical Function Method and its applications in Quantum Physics
Creators: name: Tannous, C.
name: Fakhreddine, K.
name: Langlois, J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The Canonical Function Method (CFM) is a powerful method that solves the radial Schrödinger equation for the eigenvalues directly without having to evaluate the eigenfunctions. It is applied to various quantum mechanical problems in Atomic and Molecular physics with presence of regular or singular potentials. It has also been developed to handle single and multiple channel scattering problems where the phaseshift is required for the evaluation of the scattering cross-section. Its controllable accuracy makes it a valuable tool for the evaluation of vibrational levels of cold molecules, a sensitive test of Bohr correspondance principle and a powerful method to tackle local and non-local spin dependent problems.
description: 30 pages, 12 figures- To submit to Reviews of Modern Physics
Το καθεστώς διοίκησης και διαχείρισης της περιουσίας της Εκκλησίας της Κρήτης
Creators: name: Δρακουλάκη, Εμμανουέλα-Ελένη Νικολάου
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Εκκλησιαστική περιουσία-Απαλλοτρίωση
Ν. 1700/1987
Church’s property
Confiscation-Law 1700/1987

description: Η Εκκλησία έχει ως κύριο σκοπό της τη διδασκαλία του Λόγου του Θεού, η οποία ωστόσο υλοποιείται εντός του κράτους και βάσει κοινωνικοπολιτικών και νομικών πλαισίων, ενώ παράλληλα απαιτεί τη χρήση υλικών μέσων και ανθρώπινου δυναμικού. Επομένως, η ιδιοκτησία κινητής και ακίνητης περιουσίας κρίνεται αναγκαία για την υλοποίηση του πνευματικού της σκοπού. Λόγω αυτής της αναγκαιότητας, η ρύθμιση θεμάτων εκκλησιαστικής περιουσίας, από την εποχή ακόμα των μαθητών του Χριστού, αποτέλεσε και αποτελεί καίριο ζήτημα. Η περιουσία της Εκκλησίας, ειδικά κατά τη βυζαντινή περίοδο, αυξήθηκε σε σημαντικό βαθμό και παρέμεινε μέχρι σήμερα, παρά τις όποιες παρεμβάσεις, αρκετά μεγάλη. Η διοίκηση και η διαχείριση της εκκλησιαστικής περιουσίας αποτελεί ένα σύνολο ιερών κανόνων, παγιωμένων πρακτικών της Εκκλησίας και νομοθετημάτων της Πολιτείας, ενώ αποτέλεσε διαχρονικά το σημαντικότερο ζήτημα όσον αφορά στις σχέσεις μεταξύ της Εκκλησίας και της Πολιτείας, καθώς η περιουσία αυτή δέχτηκε πλήθος νομοθετικών παρεμβάσεων με σκοπό την εκμετάλλευσή της από το Κράτος είτε με αναγκαστικές απαλλοτριώσεις είτε με δημεύσεις. Στην παρούσα μελέτη παρουσιάζεται και αναλύεται η εν λόγω συμπλοκή νόμων του Κράτους και ιερών κανόνων όσον αφορά στον τρόπο διοίκησης και διαχείρισης της εκκλησιαστικής περιουσίας της Εκκλησίας της Κρήτης, ενώ παράλληλα γίνεται αναφορά στις προσπάθειες απαλλοτρίωσης της μοναστηριακής περιουσίας της Εκκλησίας αυτής
description: The Church’s main purpose is the study of the God’s Word, which however takes place within the state based on the sociopolitical and legal limits, while requiring the use of material and human resources. Therefore, ownership of realty and chattel is necessary for the realization of its spiritual purpose. Due to this necessity, the regulation of the Church’s property, even during the students of Christ period, was also a key matter. Church’s property, especially during the Byzantine period, has significantly increased and remains so until today, despite the interventions, has high net worth. The management and administration of the Church’s assets is a whole of holy regulations, steadfast methodology of the Church and state practices, while overtime it came to be the most important issue between the Church and State relations, as this wealth suffered numerous legal interventions aimed for its exploitation by the State either by eminent domain or confiscations. In this study is presented and analyzed the fray between the State laws and the Holy rules for the management and administration of the ecclesiastical holdings of the Church of Crete, while referring to the expropriation attempts of monastery property of the Church
Dragging a polymer chain into a nanotube and subsequent release
Creators: name: Klushin, Leonid I.
name: Skvortsov, Alexander M.
name: Hsu, Hsiao-Ping
name: Binder, Kurt
Publisher: name: arXiv
Year: 2008
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We present a scaling theory and Monte Carlo (MC) simulation results for a flexible polymer chain slowly dragged by one end into a nanotube. We also describe the situation when the completely confined chain is released and gradually leaves the tube. MC simulations were performed for a self-avoiding lattice model with a biased chain growth algorithm, the pruned-enriched Rosenbluth method. The nanotube is a long channel opened at one end and its diameter $D$ is much smaller than the size of the polymer coil in solution. We analyze the following characteristics as functions of the chain end position $x$ inside the tube: the free energy of confinement, the average end-to-end distance, the average number of imprisoned monomers, and the average stretching of the confined part of the chain for various values of $D$ and for the number of monomers in the chain, $N$. We show that when the chain end is dragged by a certain critical distance $x^*$ into the tube, the polymer undergoes a first-order phase transition whereby the remaining free tail is abruptly sucked into the tube. This is accompanied by jumps in the average size, the number of imprisoned segments, and in the average stretching parameter. The critical distance scales as $x^*\sim ND^{1-1/ν}$. The transition takes place when approximately 3/4 of the chain units are dragged into the tube. The theory presented is based on constructing the Landau free energy as a function of an order parameter that provides a complete description of equilibrium and metastable states. We argue that if the trapped chain is released with all monomers allowed to fluctuate, the reverse process in which the chain leaves the confinement occurs smoothly without any jumps. Finally, we apply the theory to estimate the lifetime of confined DNA in metastable states in nanotubes.
description: 13pages, 14figures
Η χρήση της Στατιστικής κατά Bayes και της Θεωρίας Αξιοπιστίας στον υπολογισμό των Βέλτιστων Ασφαλίστρων
Creators: name: Πασχαλίδου, Ελευθερία Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2017
Subjects: Στατιστική κατά Bayes
Θεωρία Αξιοπιστίας
Μοντέλα Buhlmann-Straub
Bayes Statistics
Credibility Theory
Buhlmann-Straub Models

description: Ο κίνδυνος είναι ένα αναπόσπαστο κομμάτι της ανθρώπινης ζωής, τον οποίο είτε προσπαθούμε να τον αποφύγουμε, είτε να ελαχιστοποιήσουμε όσο το δυνατόν περισσότερο τις αρνητικές επιπτώσεις του. Σε πρώτη φάση καλούμαστε να αναγνωρίσουμε αυτόν τον κίνδυνο και τις αρνητικές επιπτώσεις που μπορεί να έχει σε εμάς. Έπειτα θα πρέπει να είμαστε σε θέση να περιγράψουμε αυτόν τον κίνδυνο και να καταγράψουμε σχετικά εμπειρικά δεδομένα και άλλες χρήσιμες πληροφορίες. Εν συνεχεία θα πρέπει να αναλύσουμε τα δεδομένα και τις πληροφορίες που έχουμε στην κατοχή μας σχετικά με τον κίνδυνο αυτό ώστε να είμαστε σε θέση να έχουμε μία τεκμηριωμένη άποψη για τα χαρακτηριστικά και τις τυχόν συνέπειες του. Και τέλος, να ασφαλίσουμε αυτόν τον κίνδυνο εάν οι συνέπειες του είναι σημαντικά επιβλαβείς προς εμάς ή δεν είμαστε σε θέση να προφυλαχτούμε οι ίδιοι έναντι αυτού. Σε ένα ιδιαιτέρως ανταγωνιστικό περιβάλλον όπως αυτό των ασφαλιστικών εταιρειών, η διόρθωση των ασφαλίστρων είναι πλέον απαραίτητη γι' αυτές. Όσα περισσότερα γνωρίζουμε για τον κίνδυνο που πρόκειται να καλύψουμε, τόσο πιο ακριβές θα είναι και το ασφάλιστρο που θα εξάγουμε. Τα μοντέλα της Θεωρίας Αξιοπιστίας μας επιτρέπουν να χρησιμοποιήσουμε την προσωπική μας εμπειρική ζημία ως βασική πληροφορία για να υπολογίσουμε το ασφάλιστρο μίας συγκεκριμένης ασφάλειας.
description: Risk is an integral part of human life, which we either try to avoid or minimize as far as possible its negative effects. Firstly we recognize the risk and its negative effects it can have on us. Then we should be able to describe this risk and record on empirical data and other useful information. Then, we need to analyze the data and information we have for that risk in order to be able to have an informed opinion about the characteristics and possible consequences. And finally, to insure this risk, if the consequences are very harmful for us or we are unable to safely guard ourselves against it. In a highly competitive environment, such as insurance companies, the adjustment of premiums is very necessary for them. The more we know about the risk to be covered, the more accurate will be the premium we will export. The Credibility Theory models allows us to use our personal injury empirical as basic information to calculate the premium of a particular insurance.
Giant Ringlike Radio Structures Around Galaxy Cluster Abell 3376
Creators: name: Bagchi, Joydeep
name: Durret, Florence
name: Neto, Gastao B. Lima
name: Paul, Surajit
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In the current paradigm of cold dark matter cosmology, large-scale structures are assembling through hierarchical clustering of matter. In this process, an important role is played by megaparsec (Mpc)-scale cosmic shock waves, arising in gravity-driven supersonic flows of intergalactic matter onto dark matter-dominated collapsing structures such as pancakes, filaments, and clusters of galaxies. Here, we report Very Large Array telescope observations of giant (~2 Mpc by 1.6 Mpc), ring-shaped nonthermal radio-emitting structures, found at the outskirts of the rich cluster of galaxies Abell 3376. These structures may trace the elusive shock waves of cosmological large-scale matter flows, which are energetic enough to power them. These radio sources may also be the acceleration sites where magnetic shocks are possibly boosting cosmic-ray particles with energies of up to 10^18 to 10^19 electron volts.
description: Published on Science, 3 November 2006. Main paper and Supporting Online Material
Microwave response of an Andreev bound state
Creators: name: Kurilovich, Pavel D.
name: Kurilovich, Vladislav D.
name: Fatemi, Valla
name: Devoret, Michel H.
name: Glazman, Leonid I.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We develop a theory for the dynamics of an Andreev bound state hosted by a weak link of finite length for which charging effects are important. We derive the linear response of both the current through the link and charge accumulated in it with respect to the phase and gate voltage biases. The resulting matrix encapsulates the spectroscopic properties of a weak link embedded in a microwave resonator. In the low-frequency limit, we obtain the response functions analytically using an effective low-energy Hamiltonian, which we derive. This Hamiltonian minimally accounts for Coulomb interaction and is suitable for a phenomenological description of a weak link having a finite length.
description: 26 pages, 7 figures. Added a footnote
peyotl
Creators: name: Vaes, Luk
Publisher: name: ÍMPAR: Online Journal for Artistic Research
Year: 2021

description: For nearly as long as the piano has existed, composers have been interested in producing sounds for which the instrument was not conceived. Whilst most of us may be at ease with a pianist’s fingers gliding over the keyboard, many feel more resistance towards someone who hits the keys with the flat of the hand, or is bent over the keyboard to play directly on the strings. Yet, these techniques have been in use since the 18th century, unlike their common association with ‘new music’. In contrast to this extensive repertoire for professionals, pieces that are written to introduce such techniques to children exhibit mostly adult aesthetic preferences. As regards performance technique, the composers have not distinguished between the different pedagogical chronologies and algorithms of learning to play the keyboard and the inside of the piano, nor do they seem to have imagined whether a child always has ready access to the accessories that are sometimes required to do so. In collaboration with composer Hans Cafmeyer, a project was set up at the Orpheus Institute to develop new music through artistic research, catering to children’s aesthetic horizons, their technical abilities, pedagogical needs, and personal biotope, and the technological constraints of the instrument. With Hans Cafmeyer’s decade-long experience in teaching children, in addition to writing music for them which suits their pedagogical level, as well as Luk Vaes’ research into the history and performance practices of extended techniques, “peyotl” was created, a collection of pieces allowing teachers to integrate extended techniques into the protocol of regular keyboard-specific pedagogy. The multimedia publication includes the score as well as online videos of the composer and children performing the music.
description: ÍMPAR: Online Journal for Artistic Research, vol. 4 n.º 1 (2020): ÍMPAR: Online Journal for Artistic Research
Editorial
Creators: name: Correia, Jorge Salgado
Publisher: name: ÍMPAR: Online Journal for Artistic Research
Year: 2021

description: I believe that Artistic Research prevails because of its power to intervene and reconfigure in a very specific intersection where subjectivity and intersubjectivity meet, where individual desires, fears and unconscious meanings nurture common beliefs, shared fictions, mythopoetic configurations. Since only the exploration of one's own subjectivity and its singularities opens up access to this field, neither philosophical nor scientific approaches are adequate or capable of meeting this challenge, focused as they are on generality. However, all the arts and all the artists explore this very same realm without overlaps and disputes by generating. through their creative work, new meanings, insights and (embodied) knowledge, and connecting us, in this way, to the ineffable. Rather than concepts and rational constructions, the ineffable demands images, gestures, emotional narratives. Artistic meaning constructions open thus to the possibility of connecting us with the ineffable establishing a continuum of images, gestures and emotional narratives were boundaries make no sense. For the same reason it doesn’t make much sense to establish frontiers within artistic research.
description: ÍMPAR: Online Journal for Artistic Research, vol. 4 n.º 1 (2020): ÍMPAR: Online Journal for Artistic Research
LAS ARTES DE LA ESCENA: MIRAR A LOS DIOSES DE FRENTE
Creators: name: Bolaños, Marifé Santiago
Publisher: name: ÍMPAR: Online Journal for Artistic Research
Year: 2020

description: Tomando como referente la razón poética de la filósofa María Zambrano, se tratará de cercar la importancia que supone la incorporación de las artes escénicas en el ámbito académico universitario. Su exclusión histórica de este territorio podría explicar, simbólicamente, la desafección y decadencia de una época y una manera compartida de estar en el mundo que sostuvieron la idea de Europa, cimentada en la igualdad, la fraternidad y la libertad. A partir de aquí, se propone revisar esa idea, buscar dónde se perdió, qué supone el abandono de sus sueños democratizadores, ofreciendo una “poética del sur” que se valiera de “metodologías del respeto”. Entre ellas, destacaríamos abordar el tema con perspectiva de género, para que el detalle y lo excluido intencionadamente del orden canónico, permitiera a la universidad cumplir su encomienda de ser creadora de espacios plurales de lo común con capacidad de acoger “lo universal” y sus enriquecedoras diferencias.
description: ÍMPAR: Online Journal for Artistic Research, vol. 4 n.º 1 (2020): ÍMPAR: Online Journal for Artistic Research
Successive destruction of charge density wave states by pressure in LaAgSb$_2$
Creators: name: Akiba, Kazuto
name: Nishimori, Hiroaki
name: Umeshita, Nobuaki
name: Kobayashi, Tatsuo C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We comprehensively studied the magnetotransport properties of LaAgSb$_2$ under high pressure up to 4 GPa, which showed unique successive charge density wave (CDW) transitions at $T_{CDW1}\sim 210$ K and $T_{CDW2}\sim 190$ K at ambient pressure. With the application of pressure, both $T_{CDW1}$ and $T_{CDW2}$ were suppressed and disappeared at the critical pressures of $P_{CDW1}=3.0$--3.4 GPa and $P_{CDW2}=1.5$--1.9 GPa, respectively. At $P_{CDW1}$, the Hall conductivity showed a step-like increase, which is consistently understood by the emergence of two-dimensional hollow Fermi surface at $P_{CDW1}$. We also observed a significant negative magnetoresistance effect when the magnetic field and current were applied parallel to the $c$ axis. Shubnikov--de Haas (SdH) oscillation measurements under pressure directly showed the changes in the Fermi surface across the CDW phase boundaries. In $PP_{CDW1}$, we observed a single frequency of $\sim 48$ T with a cyclotron effective mass of 0.066 $m_0$, whose cross section in the reciprocal space corresponded to only 0.22\% of the first Brillouin zone. Besides, we observed another oscillation component with frequency of $\sim 9.2$ T, which is significantly enhanced in the limited pressure range of $P_{CDW2}
description: 15pages, 13 figures
Cryogenic GaAs high-electron-mobility-transistor amplifier for current noise measurements
Creators: name: Lee, Sanghyun
name: Hashisaka, Masayuki
name: Akiho, Takafumi
name: Kobayashi, Kensuke
name: Muraki, Koji
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We show that a cryogenic amplifier composed of a homemade GaAs high-electron-mobility transistor (HEMT) is suitable for current-noise measurements in a mesoscopic device at dilution-refrigerator temperatures. The lower noise characteristics of our homemade HEMT leads to a lower noise floor in the experimental setup and enables more efficient current-noise measurement than is available with a commercial HEMT. We present the dc transport properties of the HEMT and the gain and noise characteristics of the amplifier. With the amplifier employed for current-noise measurements in a quantum point contact, we demonstrate the high resolution of the measurement setup by comparing it with that of the conventional one using a commercial HEMT.
description: 10 pages, 13 figures
Radio bubbles in the composite AGN-starburst galaxy NGC6764
Creators: name: Hota, Ananda
name: Saikia, D. J.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present multi-frequency radio continuum as well as HI observations of the composite galaxy NGC6764, which has a young, circumnuclear starburst and also harbours an active galactic nucleus (AGN). These observations have been made at a number of frequencies ranging from ~600 MHz to 15 GHz using both the GMRT and the VLA. They reveal the structure of the bipolar bubbles of non-thermal, radio emission which are along the minor axis of the galaxy and extend up to ~1.1 and 1.5 kpc on the northern and southern sides respectively. Features in the radio bubbles appear to overlap with filaments of H_alpha emission. The high-resolution observations reveal a compact source, likely to be associated with the nucleus of the galaxy, and a possible radio jet towards the south-west. We have compiled a representative sample of galaxies with bubbles of non-thermal radio emission and find that these are found in galaxies with an AGN. The HI observations with the GMRT show two peaks of emission on both ends of the stellar-bar and depletion of HI in the central region of the galaxy. We also detect HI in absorption against the central radio peak at the systemic velocity of the galaxy. The HI-absorption spectrum also suggests a possible weak absorption feature blue-shifted by ~120 km/s, which requires confirmation. A similar feature has also been reported from observations of CO in emission, suggesting that the circumnuclear starburst and nuclear activity affect the kinematics of the atomic and molecular gas components, in addition to the ionised gas seen in H_alpha and [N II].
description: 13 pages, 25 figures, accepted in MNRAS
Dissecting Sub-Cycle Interference in Photoelectron Holography
Creators: name: Werby, Nicholas
name: Maxwell, Andrew S.
name: Forbes, Ruaridh
name: Bucksbaum, Philip H.
name: Faria, Carla Figueira de Morisson
Publisher: name: arXiv
Year: 2021
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: Multipath holographic interference in strong-field quantum tunnel ionization is key to revealing sub-Angstrom attosecond dynamics for molecular movies. This critical sub-cycle motion is often obscured by longer time-scale effects such as ring-shaped patterns that appear in above-threshold ionization (ATI). In the present work, we overcome this problem by combining two novel techniques in theory and experimental analysis: unit-cell averaging and time-filtering data and simulations. Together these suppress ATI rings and enable an unprecedented highly-detailed quantitative match between strong-field ionization experiments in argon and the Coulomb-quantum orbit strong-field approximation (CQSFA) theory. Velocity map images reveal fine modulations on the holographic spider-like interference fringes that form near the polarization axis. CQSFA theory traces this to the interference of three types of electron pathways. The level of agreement between experiment and theory allows sensitive determination of quantum phase differences and symmetries, providing an important tool for quantitative dynamical imaging in quantum systems.
description: 13 Pages, 8 figures
El Sonido de las flautas Schwedler
Creators: name: Gimeno, María Carmen Fuentes
Publisher: name: ÍMPAR: Online Journal for Artistic Research
Year: 2020

description: Las flautas de Maximilian Schwedler surgieron en 1885 con la intención de poder competir en volumen sonoro con la flauta cilíndrica de sistema Böhm (1847), pero sin tener que renunciar al sonido característico de las flautas cónicas de madera de sistema antiguo. Maximilian Schwedler seguía una tradición sonora heredada de Anton Bernhard Fürstenau que estará vigente en Alemania hasta bien entrado el siglo XX. Las flautas construidas por Schwedler en colaboración con diversos constructores tenían posibilidades sonoras que se perdieron con el uso de la flauta de sistema Böhm y que hoy representan un reto para cualquier flautista. Este artículo se enmarca dentro de una investigación artística que pretende aprovechar los recursos sonoros de estas flautas caídas en el olvido. El reto de este trabajo de ivestigación es, por tanto, la experimentación con esas posibilidades sonoras que las flautas Schwedler ofrecen al flautista actual.
description: ÍMPAR: Online Journal for Artistic Research, vol. 4 n.º 1 (2020): ÍMPAR: Online Journal for Artistic Research
Exploring the connection between coronal and footpoint sources in a thin-thick target solar flare model
Creators: name: Battaglia, Marina
name: Benz, Arnold O.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Context: Hard X-ray emission of coronal sources in solar flares has been observed and studied since its discovery in Yohkoh observations. Several models have been proposed to explain the physical mechanisms causing this emission and the relations between those sources and simultaneously observed footpoint sources. Aims: We investigate and test one of the models (intermediate thin-thick target model) developed on the basis of Yohkoh observations. The model makes precise predictions on the shape of coronal and footpoint spectra and the relations between them, that can be tested with new instruments such as RHESSI. Methods: RHESSI observations of well observed events are studied in imaging and spectroscopy and compared to the predictions from the intermediate thin-thick target model. Results: The results indicate that such a simple model cannot account for the observed relations between the non-thermal spectra of coronal and footpoint sources. Including non-collisional energy loss of the electrons in the flare loop due to an electric field can solve most of the inconsistencies.
Topicality in the Piano Music of John ireland
Creators: name: Hellaby, Julian
Publisher: name: ÍMPAR: Online Journal for Artistic Research
Year: 2020

description: Leonard Ratner’s pioneering work on topic theory in his 1980 book Classic Music: Expression, Form and Style presented topics as 18th-century meaning-bearing aspects of musical compositions, embracing types such as dances and marches, and styles such as hunt and pastoral. Amongst other authors, Robert Hatten (1994, 2004), Raymond Monelle (2000, 2006) and Kofi Agawu (2009) have subsequently developed the concept and taken it well outside the confines of the 18th century. Despite this expansion into the 19th- and, to a lesser extent, 20th-century music, the focus of topic theory has tended to stay within the Classical period, and its interaction with performance has remained under-investigated. This article thus addresses the subject of topics in 20th-century piano music and assesses their significance for the performer. Solo piano pieces by the English composer John Ireland (1879–1962) are used as case-studies, and a variety of topics, including pictorial ones, are discovered in his music, most of them not named in a title (such as ‘Minuet in G’). Thus pastoral music is found in parts of the Rhapsody and a twentieth-century equivalent of Empfindsamkeit in ‘In A May Morning’ from Sarnia. Placing these works and others in the context of Ireland’s biography adds extra richness to the investigation. New topics are suggested for the works under consideration, one of which relates to idiomatic piano writing as a generative principle. At the heart of the article is an exploration of topicality in Ireland’s music as an aid to a pianist’s interpretative decision-making, a process which engages with the composer’s perceived codes of meaning and expression, and seeks for ways in which to project these to the listener. The essay is illustrated by video extracts featuring the author’s live and studio performances.
description: ÍMPAR: Online Journal for Artistic Research, vol. 4 n.º 1 (2020): ÍMPAR: Online Journal for Artistic Research
A Vector Supersymmetry in Noncommutative U(1) Gauge Theory with the Slavnov Term
Creators: name: Blaschke, Daniel N.
name: Gieres, Francois
name: Piguet, Olivier
name: Schweda, Manfred
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We consider noncommutative U(1) gauge theory with the additional term, involving a scalar field lambda, introduced by Slavnov in order to cure the infrared problem. we show that this theory, with an appropriate space-like axial gauge-fixing, wxhibits a linear vector supersymmetry similar to the one present in the 2-dimensional BF model. This vector supersymmetry implies that all loop corrections are independent of the $λAA$-vertex and thereby explains why Slavnov found a finite model for the same gauge-fixing.
description: 18 pages, 3 figures; v2 Acknowledgments added
First Principles Calculation of Ballistic Current from Electron-Hole Interaction
Creators: name: Dai, Zhenbang
name: Rappe, Andrew M.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Computational Physics (physics.comp-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The bulk photovoltaic effect (BPVE) has attracted an increasing interest due to its potential to overcome the efficiency limit of traditional photovoltaics, and much effort has been devoted to understanding its underlying physics. However, previous work has shown that theoretical models of the shift current and the phonon-assisted ballistic current in real materials do not fully account for the experimental BPVE photocurrent, and so other mechanisms should be investigated in order to obtain a complete picture of BPVE. In this Letter, we demonstrate two approaches that enable the ab initio calculation of the ballistic current originating from the electron-hole interaction in semiconductors. Using BaTiO$_3$ and MoS$_2$ as two examples, we show clearly that for them the asymmetric scattering from electron-hole interaction is less appreciable than that from electron-phonon interaction, indicating more scattering processes need to be included to further improve the BPVE theory. Moreover, our approaches build up a venue for predicting and designing materials with larger ballistic current due to electron-hole interactions.