cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
New reaction rate for 16O(p,gamma)17F and its influence on the oxygen isotopic ratios in massive AGB stars
Creators: name: Iliadis, C.
name: Angulo, C.
name: Descouvemont, P.
name: Lugaro, M.
name: Mohr, P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The 16O(p,gamma)17F reaction rate is revisited with special emphasis on the stellar temperature range of T=60-100 MK important for hot bottom burning in asymptotic giant branch (AGB) stars. We evaluate existing cross section data that were obtained since 1958 and, if appropriate, correct published data for systematic errors that were not noticed previously, including the effects of coincidence summing and updated effective stopping powers. The data are interpreted by using two different models of nuclear reactions, that is, a potential model and R-matrix theory. A new astrophysical S-factor and recommended thermonuclear reaction rates are presented. As a result of our work, the 16O(p,gamma)17F reaction has now the most precisely known rate involving any target nucleus in the mass A >= 12 range, with reaction rate errors of about 7% over the entire temperature region of astrophysical interest (T=0.01-2.5 GK). The impact of the present improved reaction rate with its significantly reduced uncertainties on the hot bottom burning in AGB stars is discussed. In contrast to earlier results we find now that there is not clear evidence to date for any stellar grain origin from massive AGB stars.
description: 14 pages, 9 figures, PRC, accepted
The ZTF Source Classification Project: I. Methods and Infrastructure
Creators: name: van Roestel, Jan
name: Duev, Dmitry A.
name: Mahabal, Ashish A.
name: Coughlin, Michael W.
name: Mróz, Przemek
name: Burdge, Kevin
name: Drake, Andrew
name: Graham, Matthew J.
name: Hillenbrand, Lynne
name: Fremling, C.
name: Hale, David
name: Laher, Russ R.
name: Masci, Frank J.
name: Riddle, Reed
name: Rosnet, Philippe
name: Rusholme, Ben
name: Smith, Roger
name: Soumagnac, Maayane T.
name: Walters, Richard
name: Prince, Thomas A.
name: Kulkarni, S. R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The Zwicky Transient Facility (ZTF) has been observing the entire northern sky since the start of 2018 down to a magnitude of 20.5 ($5 σ$ for 30s exposure) in $g$, $r$, and $i$ filters. Over the course of two years, ZTF has obtained light curves of more than a billion sources, each with 50-1000 epochs per light curve in $g$ and $r$, and fewer in $i$. To be able to use the information contained in the light curves of variable sources for new scientific discoveries, an efficient and flexible framework is needed to classify them. In this paper, we introduce the methods and infrastructure which will be used to classify all ZTF light curves. Our approach aims to be flexible and modular and allows the use of a dynamical classification scheme and labels, continuously evolving training sets, and the use of different machine learning classifier types and architectures. With this setup, we are able to continuously update and improve the classification of ZTF light curves as new data becomes available, training samples are updated, and new classes need to be incorporated.
Παραγωγίσεις του ελεύθερου Lie δακτυλίου και ΙΑ-αυτομορφισμοί της ελεύθερης ομάδας
Creators: name: Ελευθεριάδου, Ιωάννα-Ηρώ Χρήστου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: ΙΑ- αυτομορφισμοί
Ελεύθερες ομάδες
Παραγωγίσεις
IA-automorphisms
Free groups
Derivations

description: Στην παρούσα διπλωματική εργασία μελετάμε τη σύνδεση μεταξύ των ΙΑ-αυτομορφισμών της ελεύθερης ομάδας πεπερασμένης βαθμίδας n και των παραγωγίσεων του ελεύθερου Lie δακτυλίου. Ορίζουμε την Johnson Lie άλγεβρα των ΙΑ-αυτομορφισμών της ελεύθερης ομάδας βαθμίδας n και την Lie άλγεβρα του ελεύθερου Lie δακτυλίου. Αποδεικνύεται ότι η κ-ομογενής συνιστώσα της Johnson Lie άλγεβρας εμφυτεύεται στην (κ-1)-ομογενή συνιστώσα της Lie άλγεβρας των παραγωγίσεων του ελεύθερου Lie δακτυλίου. Το αποτέλεσμα αυτό συνδέεται με την εικασία Ανδρεαδάκη.
description: In this thesis we study the connection between the IA-automorphisms of the free group of finite rank n and the derivations of the free Lie ring. We define the Johnson Lie algebra of the IA-automorphisms of the free group of rank n and the Lie algebra of the free Lie ring and we prove that the k-homogeneous component of the Johnson Lie algebra is embedded in the (k-1)-homogeneous component of the Lie algebra of the derivations of the free Lie ring. This result is related to the Andreadakis' conjecture.
Καταγραφή και χαρτογράφηση των συστημάτων διαχείρισης δασικών πυρκαγιών στην Ελλάδα
Creators: name: Μπίζμπα-Πολίτη, Ελευθερία Σπυρίδωνα
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: Χαρτογράφηση
Συστήματα διαχείρισης
Δασικών πυρκαγιών
Mapping
Forest fire
Management systems

description: Οι δασικές πυρκαγιές αποτελούν ένα πολύ σημαντικό πρόβλημα των σύγχρονων κοινωνιών τόσο στην Ελλάδα, όσο και στο εξωτερικό. Η ανάπτυξη της τεχνολογίας, των ηλεκτρονικών υπολογιστών και της τηλεπισκόπησης έρχεται να δώσει λύση στον έγκαιρο εντοπισμό και την διαχείριση των δασικών πυρκαγιών. Πανεπιστημιακοί φορείς αλλά και ιδιωτικές εταιρείες έχουν σχεδιάσει και υλοποιήσει ολοκληρωμένα συστήματα ανίχνευσης και διαχείρισης δασικών πυρκαγιών με την βοήθεια των γεωγραφικών συστημάτων πληροφοριών. Στην παρούσα εργασία έγινε μια προσπάθεια να περιγράφουν τα συστήματα που υλοποιήθηκαν στην χώρα μας, να συγκριθούν μεταξύ τους και να χαρτογραφηθούν με τη βοήθεια ενός γεωγραφικού συστήματος πληροφορίων.
description: This project titled “Documenting and Mapping the Forest Fire Management Systems implemented in Greece”, deals with the major problem of forest fires in modern societies in Greece and abroad. The development of technology, computing and remote sensing has given solutions to the early detection and management of forest fires. Academic researchers and private companies have designed and implemented integrated forest fires management systems with the assistance of geographic information systems. This study is an attempt to describe the systems implemented mainly in our country, to make comparisons between them and to map them through a geographic information system.
The complexity of evolution on graphs
Creators: name: Chatterjee, Krishnendu
name: Ibsen-Jensen, Rasmus
name: Nowak, Martin
Publisher: name: IST Austria
Year: 2014
Subjects: 000 Computer science, knowledge & general works

description: Evolution occurs in populations of reproducing individuals. The structure of the population affects the outcome of the evolutionary process. Evolutionary graph theory is a powerful approach to study this phenomenon. There are two graphs. The interaction graph specifies who interacts with whom in the context of evolution. The replacement graph specifies who competes with whom for reproduction. The vertices of the two graphs are the same, and each vertex corresponds to an individual. A key quantity is the fixation probability of a new mutant. It is defined as the probability that a newly introduced mutant (on a single vertex) generates a lineage of offspring which eventually takes over the entire population of resident individuals. The basic computational questions are as follows: (i) the qualitative question asks whether the fixation probability is positive; and (ii) the quantitative approximation question asks for an approximation of the fixation probability. Our main results are: (1) We show that the qualitative question is NP-complete and the quantitative approximation question is #P-hard in the special case when the interaction and the replacement graphs coincide and even with the restriction that the resident individuals do not reproduce (which corresponds to an invading population taking over an empty structure). (2) We show that in general the qualitative question is PSPACE-complete and the quantitative approximation question is PSPACE-hard and can be solved in exponential time.
Λογαριθμική χωρητικότητα. Ιδιότητες και εφαρμογές
Creators: name: Χατζηπαναγιώτου, Βασίλειος Νικολάου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: Λογαριθμική χωρητικότητα
Θεωρία δυναμικού
Υπερπεπερασμένη διάμετρος
Logarithmic capacity
Potential theory
Transfinite diameter

description: Το κύριο θέμα της εργασίας είναι η λογαριθμική χωρητικότητα. Χρησιμοποιούνται στοιχεία θεωρίας δυναμικού, η μιγαδική ανάλυση και κάποια στοιχεία θεωρίας μέτρου. Ορίζεται το δυναμικό και η ενέργεια ενός πεπερασμένου μέτρου Borel σε συμπαγές μιγαδικό σύνολο K, καθώς και το μέτρο ισορροπίας του Κ. Ορίζουμε τη λογαριθμική χωρητικότητα. Παρουσιάζονται κάποιες ιδιότητες και μερικά θεωρήματα για τον υπολογισμό της με βάση τη σχέση της με τις συναρτήσεις Green. Υπολογίζουμε τη χωρητικότητα μερικών στοιχειωδών συνόλων όπως ο δίσκος, η έλλειψη και το ευθύγραμμο τμήμα. Δίνουμε κάποιες προτάσεις για την εκτίμηση της χωρητικότητας μέσω άνω ή/και κάτω φραγμάτων και μια εκτίμηση για το γενικευμένο σύνολο Cantor. Ορίζεται η n-διάμετρος συμπαγούς συνόλου και η υπερπεπερασμένη διάμετρος η οποία (όπως τελικά προκύπτει) είναι έννοια ταυτόσημη με τη λογαριθμική χωρητικότητα. Αποδεικνύουμε το σχετικό θεώρημα (Fekete-Szego). Τέλος, παρουσιάζουμε μερικές εφαρμογές της λογαριθμικής χωρητικότητας όπως: το θεώρημα Koebe ¼ και μια γενίκευσή του, το θεώρημα lemniscate του Hilbert, μια βελτιωμένη μορφή του θεωρήματος Runge, μια εφαρμογή στα ομογενή πολυώνυμα και τη χωρητικότητα του συνόλου Julia της δυναμικής πολυωνύμων.
description: The aim of the present thesis is the study of the logarithmic capacity. We use complex analysis, some potential theory and elements of measure theory. We define the potential and the energy of a finite Borel measure on a compact set K and the equilibrium measure of K. We define logarithmic capacity, give its properties and prove some theorems for computation through Green functions. We compute capacity for some basic sets as a disk, an ellipsis and a segment. We present some theorems for the estimation of capacity (through lower or/and upper boundaries) and an estimation for the generalized Cantor set. We define the n-diameter and the transfinite diameter of a compact set, which is just its logarithmic capacity. (We prove the related Fekete-Szego theorem). Finally, we give some applications of the logarithmic capacity: the Koebe quarter theorem and a generalization of it, Hilbert’s lemniscate theorem, a slightly improved version of Runge’s approximation theorem, an application to homogenous polynomials and the capacity of Julia set of complex dynamics.
Improved Atomic Transition Probabilities for UV and Optical Lines of Hf II and Determination of the Hf Abundance in Two Metal-Poor Stars
Creators: name: Hartog, E. A. Den
name: Lawler, J. E.
name: Roederer, I. U.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We report new branching fraction measurements for 199 UV and optical transitions of Hf II. These transitions range in wavelength (wavenumber) from 2068- 6584 A (48322-15183 cm-1) and originate in 17 odd-parity upper levels ranging in energy from 38578-53227 cm-1. The branching fractions are combined with radiative lifetimes reported in an earlier study to produce a set of transition probabilities and log(gf) values with accuracy ranging from 5-25%. Comparison is made to transition probabilities from the literature where such data exist. We use these new transition probabilities to derive improved Hf abundances in two metal-poor stars. HD 196944 is enhanced in s-process elements, and we derive log epsilon (Hf) = -0.72 +/- 0.03 (sigma = 0.09) from 12 Hf II lines. HD 222925 is enhanced in r-process elements, and we derive log epsilon (Hf) = 0.32 +/- 0.03 (sigma = 0.11) from 20 Hf II lines. These measurements greatly expand the number of potentially useful Hf II lines for analysis in UV and optical spectra.
description: Accepted for publication in the Astrophysical Journal Supplement Series (32 pages, 4 figures, 4 tables)
Προσδιορισμός εδαφικών παραμέτρων ρυπασμένων εδαφών με τη χρήση φασματοσκοπίας ανάκλασης εδάφους
Creators: name: Αγγελοπούλου, Θεοδώρα Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: ρύπανση εδαφών,
βαρέα μέταλλα
φασματοσκοπία ανάκλασης εδάφους
soil pollution
heavy metals
soil reflectance spectroscopy

description: Η παρούσα μεταπτυχιακή διατριβή είχε ως αντικείμενο την εκτίμηση της ρύπανσης των εδαφών από βαρέα μέταλλα στο Δυτικό παράκτιο μέτωπο της Θεσσαλονίκης. Η εκτίμηση πραγματοποιήθηκε με εδαφολογικές χημικές αναλύσεις και τη χρήση της φασματοσκοπίας ανάκλασης εδάφους στο ορατό και κοντινό υπέρυθρο (Vis-NIR), ως εναλλακτική μέθοδος εκτίμησης των συγκεντρώσεων των βαρέων μετάλλων στο έδαφος. Συνολικά συλλέχθηκαν 49 δείγματα επιφανειακού εδάφους και προσδιορίστηκαν οι συγκεντρώσεις τους σε Cd, Cr, Cu και Pb με δύο διαφορετικές χημικές αναλυτικές μεθόδους, την AAS και την ICP-AES. Έπειτα οι φασματικές τους υπογραφές χρησιμοποιήθηκαν για τη δημιουργία μοντέλων πρόβλεψης των συγκεντρώσεων των μετάλλων με τη χρήση της παλινδρόμησης ελαχίστων τετραγώνων (PLSR). Για τη μείωση του θορύβου χρησιμοποιήθηκαν οι κοινές μέθοδοι προ επεξεργασίας των φασματικών δεδομένων και η ορθογωνική διόρθωση σήματος (OSC), η οποία δεν έχει μελετηθεί σε μεγάλο βαθμό στη φασματοσκοπία ανάκλασης εδάφους. Τα αποτελέσματα έδειξαν ότι σε συγκεκριμένες περιοχές υπάρχει ρύπανση από βαρέα μέταλλα και ότι δύο διαφορετικές χημικές αναλύσεις μπορούν να επηρεάσουν την επίδοση των μοντέλων πρόβλεψης. Η χρήση της OSC αφαιρώντας τις περιττές πληροφορίες από το φάσμα βελτίωσε την ακρίβεια των προβλέψεων των συγκεντρώσεων των βαρέων μετάλλων στο έδαφος. Καλύτερα μοντέλα πρόβλεψης δημιουργήθηκαν για τα Pb, Cu και Cr των οποίων οι συγκεντρώσεις μετρήθηκαν με την ICP-AES, ενώ για το Cd καλύτερα μοντέλα πρόβλεψης όταν οι συγκεντρώσεις μετρήθηκαν με την AAS.
description: This Master thesis aim was to estimate soil heavy metal pollution in the western coastal front of Thessaloniki. For this study soil chemical analyses and soil reflectance spectroscopy in the visible and near infrared (Vis-NIR), as an alternative method for estimating concentrations of heavy metals in soil, were combined. 49 topsoil samples were collected and concentrations of Cd, Cr, Cu and Pb were determined by two different chemical analytical methods, AAS and ICP-AES. Spectral signatures were used for modeling metal concentrations using partial least squares regression (PLSR). For noise reduction, the common pre-processing methods of the spectral data were used along with orthogonal signal correction (OSC), which hasn’t been largely studied in soil reflectance spectroscopy. The use OSC removed irrelevant information from the spectra range and improved prediction accuracy. The results showed that there is soil heavy metal pollution in specific areas of the region and that different chemical analyses can affect the performance of the prediction models. Better predictive models created for Pb, Cu and Cr whose concentrations were estimated by ICP-AES, while for Cd better predictive models when concentrations were estimated by AAS.
A Pluto--Charon Concerto II. Formation of a Circumbinary Disk of Debris After the Giant Impact
Creators: name: Kenyon, Scott J.
name: Bromley, Benjamin C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Using a suite of numerical calculations, we consider the long-term evolution of circumbinary debris from the Pluto-Charon giant impact. Initially, these solids have large eccentricity and pericenters near Charon's orbit. On time scales of 100-1000 yr, dynamical interactions with Pluto and Charon lead to the ejection of most solids from the system. As the dynamics moves particles away from the barycenter, collisional damping reduces the orbital eccentricity of many particles. These solids populate a circumbinary disk in the Pluto-Charon orbital plane; a large fraction of this material lies within a `satellite zone' that encompasses the orbits of Styx, Nix, Kerberos, and Hydra. Compared to the narrow rings generated from the debris of a collision between a trans-Neptunian object (TNO) and Charon, disks produced after the giant impact are much more extended and may be a less promising option for producing small circumbinary satellites.
description: AJ in press, 28 pages with 2 tables and 11 figures
NRQCD and Quarkonia
Creators: name: Brambilla, Nora
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We review recent progress in Non-Relativistic QCD and in related Non-Relativistic Effective Field Theories with emphasis on the applications to heavy quarkonia.
description: 24 pages, invited talk at the Conference HQL06, Munich, October 16-20 2006. One reference added
Polarization of absorption lines as a diagnostics of circumstellar, interstellar and intergalactic magnetic fields: Fine structure atoms
Creators: name: Yan, Huirong
name: Lazarian, A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The relative population of the fine structure sublevels of an atom's ground state is affected by radiative transitions induced by an anisotropic radiation flux. This causes the alignment of atomic angular momentum. In terms of observational consequences for the interstellar and intergalactic medium, this results in the polarization of the absorption lines. In the paper we consider the conditions necessary for this effect and provide calculations of polarization from a few astrophysically important atoms and ions with multiple upper and lower levels for an arbitrary orientation of magnetic fields to the a) source of optical pumping, b) direction of observation, c) absorbed source. We also consider an astrophysically important ``degenerate'' case when the source of optical pumping coincides with the source of the absorbed radiation. We present analytical expressions that relate the degree of linear polarization and the intensity of absorption to the 3D orientation of the magnetic field with respect to the pumping source, the source of the absorbed radiation, and the direction of observations. We discuss how all these parameters can be determined via simultaneous observations of several absorption lines and suggest graphical means that are helpful in practical data interpretation. We prove that studies of absorption line polarization provide a unique tool to study 3D magnetic field topology in various astrophysical conditions.
description: 22 pages, 10 figures, ApJ, in press
Diffractive Excitation of Heavy Flavors: Leading Twist Mechanisms
Creators: name: Kopeliovich, B. Z.
name: Potashnikova, I. K.
name: Schmidt, I.
name: Tarasov, A. V.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Diffractive production of heavy flavors is calculated within the light-cone dipole approach. Novel leading twist mechanisms are proposed, which involve both short and long transverse distances inside the incoming hadron. Nevertheless, the diffractive cross section turns out to be sensitive to the primordial transverse momenta of projectile gluons, rather than to the hadronic size. Our calculations agree with the available data for diffractive production of charm and beauty, and with the observed weak variation of the diffraction-to-inclusive cross section ratios as function of the hard scale.
description: Latex, 19 pages, 12 figures. A short commenting on previously done computations is added
Frequency-Resolved Spatial Beam Mapping in Multimode Fibers: Application to Mid-Infrared Supercontinuum Generation
Creators: name: Leventoux, Y.
name: Granger, G.
name: Krupa, K.
name: Mansuryan, T.
name: Fabert, M.
name: Tonello, A.
name: Wabnitz, S.
name: Couderc, V.
name: Fevrier, S.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We present a new spatial-spectral mapping technique permitting to measure the beam intensity at the output of a graded-index (GRIN) multimode fiber with sub-nanometric spectral resolution. We apply this method to visualize the fine structure of the beam shape of a sideband generated at 1870 nm by geometric parametric instability (GPI) in a GRIN fiber. After spatial-spectral characterization, we amplify the GPI sideband with a Tm-doped fiber amplifier to obtain a microjoule-scale picosecond pump whose spectrum is finally broadened in a segment of InF3 optical fiber to achieve supercontinuum ranging from 1.7 μm up to 3.4 μm
description: 4 pages, 6 Figures
Ethnicity and community : southern Chinese immigrants and descendants in Vancouver, 1945-1980
Creators: name: Ng, Wing
Publisher: name: University of British Columbia
Year: 2008

description: This study seeks to understand Chinese ethnicity as a process of ongoing cultural construction engaged in by Chinese people in Vancouver from 1945 to 1980. Drawing evidence primarily from the ethnic press and voluntary organizations, it uncovers a diversity of cultural positions articulated by different groups of Chinese with respect to their ethnic identity and sense of community. This interior discourse on Chineseness unfolded in part because of changing demographic conditions within the ethnic group. After the Second World War, the older settlers who had arrived in Canada before the exclusion act of 1923 were joined and gradually outnumbered by their Canadian-born descendants and new immigrants. This development ushered in a contest for the power of cultural definition among various generations of local-born and immigrant Chinese. The emergent diversity of ethnic constructs in the Chinese minority after 1945 also reflected the continuous influence of China and the new opportunities Chinese people began to enjoy in Canada. The former unitary outlook of the ethnic group regarding the close relationship of overseas Chinese with their home country was displaced, but not by any simple cultural re-orientation to Canada. Particularly among the immigrant Chinese, the concern forthe native place, the care for family members in Mainland China and Hong Kong, the desire to promote some form of Chinese culture in Vancouver, and a residual interest in Chinese politics remained salient dimensions of their ethnic consciousness. At the same time, the dismantling of discriminatory legislation and other racial barriers in the larger society afforded Chinese people for the first time the option to nurture an identification with Canada. In the 1970s these two fundamentally different cultural orientations were reconciled, as the discourse on Chineseness took on a new paradigm. Under state multiculturalism and with the rise of ethnic sentiments, members of the Chinese minority advanced their claims to be "Chinese Canadians" within the officially enshrined Canadian mosaic. Despite popular subscription to this category, immigrant and local-born Chinese invested this label with different meanings. The underlying diversity of Chinese ethnic construction was once again unveiled.
Universality in a 2-component Fermi System at Finite Temperature
Creators: name: Rupak, Gautam
Publisher: name: arXiv
Year: 2006
Subjects: subject: Nuclear Theory (nucl-th)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Thermodynamic properties of a fermionic system close to the unitarity limit, where the 2-body scattering length |a| approaches infinity is studied at high temperature Boltzmann regime. For dilute systems the virial expansion coefficients in the Boltzmann regime are expected, from general arguments, to be universal. A model independent finite temperature T calculation of the third virial coefficient b3(T) is presented. At the unitarity limit, b3(T) = -0.48 is an universal number. The energy density up to the third virial expansion is derived. These results are relevant for dilute neutron matter and could be tested in current atomic experiments on dilute fermionic gases near the Feshbach resonance.
description: 10 pages, 6 figures, LaTeX2e
Pure Gauge SU(2) Seiberg-Witten Theory and Modular Forms
Creators: name: Vogeler, Kirsten
name: Flohr, Michael
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We identify the spectral curve of pure gauge SU(2) Seiberg-Witten theory with the Weierstrass curve $\mathbbm{C}/L \ni z \mapsto (1,\wp(z),\wp(z)')$ and thereby obtain explicitely a modular form from which the moduli space parameter $u$ and lattice parameters $a$, $a_D$ can be derived in terms of modular respectively theta functions. We further discuss its relationship with the $c=-2$ triplet model conformal field theory.
description: 11 + 2 pages, no figures, shortened, to be published in jmp
Prime thick subcategories and spectra of derived and singularity categories of noetherian schemes
Creators: name: Matsui, Hiroki
Publisher: name: arXiv
Year: 2021
Subjects: subject: Algebraic Geometry (math.AG)
subject: Commutative Algebra (math.AC)
subject: Category Theory (math.CT)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 13D09, 13H10, 14J60, 18E30

description: For an essentially small triangulated category $\mathcal{T}$, we introduce the notion of prime thick subcategories and define the spectrum of $\mathcal{T}$, which shares the basic properties with the spectrum of a tensor triangulated category introduced by Balmer. We mainly focus on triangulated categories that appear in algebraic geometry such as the derived and the singularity categories of a noetherian scheme $X$. We prove that certain classes of thick subcategories are prime thick subcategories of these triangulated categories. Furthermore, we use this result to show that certain subspaces of $X$ are embedded into their spectra as topological spaces.
description: 20 pages
Precision Magnetometers for Aerospace Applications
Creators: name: Bennett, James S.
name: Vyhnalek, Brian E.
name: Greenall, Hamish
name: Bridge, Elizabeth M.
name: Gotardo, Fernando
name: Forstner, Stefan
name: Harris, Glen I.
name: Miranda, Félix A.
name: Bowen, Warwick P.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: Aerospace technologies are crucial for modern civilization; space-based infrastructure underpins weather forecasting, communications, terrestrial navigation and logistics, planetary observations, solar monitoring, and other indispensable capabilities. Extraplanetary exploration -- including orbital surveys and (more recently) roving, flying, or submersible unmanned vehicles -- is also a key scientific and technological frontier, believed by many to be paramount to the long-term survival and prosperity of humanity. All of these aerospace applications require reliable control of the craft and the ability to record high-precision measurements of physical quantities. Magnetometers deliver on both of these aspects, and have been vital to the success of numerous missions. In this review paper, we provide an introduction to the relevant instruments and their applications. We consider past and present magnetometers, their proven aerospace applications, and emerging uses. We then look to the future, reviewing recent progress in magnetometer technology. We particularly focus on magnetometers that use optical readout, including atomic magnetometers, magnetometers based on quantum defects in diamond, and optomechanical magnetometers. These optical magnetometers offer a combination of field sensitivity, size, weight, and power consumption that allows them to reach performance regimes that are inaccessible with existing techniques. This promises to enable new applications in areas ranging from unmanned vehicles to navigation and exploration.
A nuclear magnetic resonance study of UNI₂AL₃
Creators: name: Gardner, Michael W.
Publisher: name: University of British Columbia
Year: 2008

description: The theory for the combined effects of both a quadrupolar interaction and a Knight shift has been examined for the case of non-axial symmetry. A detailed derivation is given, correct to second order in perturbation theory, for the case where the quadrupole interaction is significantly smaller than the Zeeman interaction. These results have been applied to the study of the Al' nuclear magnetic resonance spectrum of a single crystal of UNi2A/3, measured using a steady state technique. A value for the asymmetry of the electric field gradient has also been determined for this material. In addition, the temperature dependence of the Knight shift was observed over the range of 6 to 300K.No significant temperature dependence was found over this range.
The sensitivity and stability of the ocean's thermohaline circulation to finite amplitude perturbations
Creators: name: Mu, Mu
name: Sun, Liang
name: Dijkstra, Henk A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Atmospheric and Oceanic Physics (physics.ao-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Within a simple model context, the sensitivity and stability of the thermohaline circulation to finite amplitude perturbations is studied. A new approach is used to tackle this nonlinear problem. The method is based on the computation of the so-called Conditional Nonlinear Optimal Perturbation (CNOP) which is a nonlinear generalization of the linear singular vector approach (LSV). It is shown that linearly stable thermohaline circulation states can become nonlinearly unstable and the properties of the perturbations with optimal nonlinear growth are determined. An asymmetric nonlinear response to perturbations exists with respect to the sign of finite amplitude freshwater perturbations, on both thermally dominated and salinity dominated thermohaline flows. This asymmetry is due to the nonlinear interaction of the perturbations through advective processes.
description: 40 pages, 13 figures
Το θέμα της Δευτέρας Παρουσίας στις εικόνες
Creators: name: Σιώπης, Ιωάννης Παναγιώτη
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: Δευτέρα Παρουσία
Εικόνες
Βυζαντινή Τέχνη
Last Judgment
Icons
Byzantine Art

description: Σκοπός της διατριβής είναι η μελέτη της σύνθεσης της Δευτέρας Παρουσίας στη ζωγραφική των φορητών εικόνων. Πρόκειται για μια εικονογραφική μελέτη που πραγματεύεται για πρώτη φορά συστηματικά τη σκηνή της Δευτέρας Παρουσίας σε ένα σύνολο 34 εικόνων, από τις οποίες δύο είναι μόνο βυζαντινές και οι υπόλοιπες ελληνικές μεταβυζαντινές, εκ των οποίων μία αδημοσίευτη. Η εν λόγω μελέτη επιχειρεί να θέσει και να αντιμετωπίσει σε επίπεδο ερμηνείας το ζήτημα της περιορισμένης διάδοσης του θέματος στην βυζαντινή εικονογραφική παράδοση των εικόνων και αντιστοίχως τη ραγδαία διάδοση του κατά τη μεταβυζαντινή περίοδο. Η εργασία διαιρείται σε τρία κεφάλαια και καταλήγει στα συμπεράσματα. Η πλούσια βιβλιογραφία και το εποπτικό υλικό κλείνουν την παρούσα μελέτη.
description: The aim of the thesis is to study the composition of the Last Judgment in the painting of icons. It is a pictorial study first discusses systematically the scene of the Last Judgment on a set of 34 images, two of which are only Byzantine and other post-Byzantine Greek, one of which is unpublished. This study attempts to raise and deal in interpretation level the issue of the limited distribution of the subject of the Last Judgment in the Byzantine iconographic tradition of images and correspondingly the rapidly spread of it during the post-Byzantine period. The thesis is divided into three chapters and closes with the conclusions. The rich bibliography and visual material are closing this study.
The Unified Model of Active Galactic Nuclei: II. Evolutionary Connection
Creators: name: Wang, Jian-Min
name: Zhang, En-Peng
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: (Abbreviated) We assemble a sample composed of 243 nearby Seyfert galaxies with redshifts $z\le 0.05$ to test the unification scheme. The sample contains 94 BLS1s, 44 NLS1s, 36 X-ray absorbed HBLR S2s, 42 X-ray absorbed non-HBLR S2s and 27 X-ray unabsorbed Seyfert 2s (unabsorbed non-HBLR S2s and HBLR S2s). We find that: 1) NLS1s have less massive black hole masses than BLS1s; 2) HBLRS2s have the same mass distribution of the black holes with BLS1s; 3) the absorbed non-HBLR S2s have less massive black holes than HBLR S2s; 4) unabsorbed non-HBLR S2s have the most massive black holes. We thus have a queue of black hole masses from small to large: narrow to broad line Seyfert galaxies, providing new evidence for the evolutionary sequence of Seyfert galaxies. We find that the opening angles of the torus in NLS1s and absorbed non-HBLR S2s are significantly smaller than that in BLS1s and HBLR S2s. The growth of the black holes and increases of the opening angles of the tori determine the various appearances of Seyfert galaxies. We also find that the unabsorbed Seyfert 2 galaxies could be caused by low gas-to-dust ratios in the present sample. This indicates that the star formation histories could be different in the unabsorbed from in absorbed Seyfert 2 galaxies, showing evidence for suppressed star formation by black hole activities. We outline a new unification scheme based on the orientation hypothesis: Seyfert galaxies can be unified by including growth of black holes, Eddington ratios, changing opening angles of tori and gas-to-dust ratios in the tori. Seyfert galaxies are tending to finally evolve to unabsorbed non-HBLR Seyfert 2 galaxies, in which the black holes are accreting with low accretion rates and both the broad line region and dusty torus disappear.
description: ApJ, vol 661 (2007), in press
Temperature dependent equilibration of spin orthogonal quantum Hall edge modes
Creators: name: Maiti, Tanmay
name: Agarwal, Pooja
name: Purkait, Suvankar
name: Sreejith, G J
name: Das, Sourin
name: Biasiol, Giorgio
name: Sorba, Lucia
name: Karmakar, Biswajit
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Conductance of the edge modes as well as conductance across the co-propagating edge modes around the ν= 4/3, 5/3 and 2 quantum Hall states are measured by individually exciting the modes. Temperature dependent equilibration rates of the outer unity conductance edge mode are presented for different filling fractions. We find that the equilibration rate of the outer unity conductance mode at ν= 2 is higher and more temperature sensitive compared to the mode at fractional filling 5/3 and 4/3. At lowest temperature, equilibration length of the outer unity conductance mode tends to saturate with lowering filling fraction νby increasing magnetic field B. We speculate this saturating nature of equilibration length is arising from an interplay of Coulomb correlation and spin orthogonality.
description: 7 pages
Solubilization of direct black 2 in mixed micellar media: insights from spectroscopic and conductometric measurements
Creators: name: Irshad, Saira
name: Sultana, Hamadia
name: Usman, Muhammad
name: Akram, Nadia
name: Farooqi, Zahoor H.
name: Yusaf, Amnah
name: Nazar, Muhammad Faizan
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biophysics
subject: Biochemistry
subject: Space Science
subject: Physical Sciences not elsewhere classified
subject: Medicine
subject: Microbiology
subject: FOS: Biological sciences
subject: Neuroscience
subject: Pharmacology
subject: Biotechnology
subject: Chemical Sciences not elsewhere classified
subject: Ecology
subject: Immunology
subject: FOS: Clinical medicine

description: The core-shell architecture of surfactant micelles serves as a super solvent to remove inevitable organic pollutants from industrial wastewater. In the present study, the synergistic mechanism improving the aqueous solubility of Direct Black 2 dye by a single cationic surfactant, cetyltrimethylammonium bromide (CTAB), and its composite solutions with nonionic surfactants, Triton X-100 (TX-100) and Tween 20 (Tw-20), has been studied in detail. The spectral behavior of dye was monitored in the presence of a surfactant from its pre-to-post micellar concentration. It was found that solubilization was greatly enhanced in the cationic-nonionic mixed micelle systems. The value of the binding constant (Kb) was 9.10 × 104 dm3/mol for CTAB, which was increased significantly increased to 58.45 × 104 dm3/mol for CTAB + Tw-20 and 86.82 × 104 dm3/mol for CTAB + TX-100. The value of the partition coefficient (Kx) also increased in a similar manner. The observed order of the extent of dye solubilization in micellar system was: CTAB < CTAB + Tw-20 < CTAB + TX-100. The enhanced solubility of dye in mixed surfactant solutions was attributed to higher aggregation number, lower critical micelle concentration (CMC) and more hydrophobic interior of micelle. Moreover, the degree of ionization degree (β), the CMC and related thermodynamic parameters were calculated from conductometric measurements, the results of which showed that the solubilization process in all types of surfactant systems is spontaneous and thermodynamically feasible, which may contribute to the sustained release of active-ingredients through self-assemblies.
Physical accessible transformations on a finite number of quantum states
Creators: name: Zhou, Xiang-Fa
name: Lin, Qing
name: Zhang, Yong-Sheng
name: Guo, Guang-Can
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We consider to treat the usual probabilistic cloning, state separation, unambiguous state discrimination, \emph{etc} in a uniform framework. All these transformations can be regarded as special examples of generalized completely positive trace non-increasing maps on a finite number of input states. From the system-ancilla model we construct the corresponding unitary implementation of pure $\to$ pure, pure $\to$ mixed, mixed $\to$ pure, and mixed $\to$ mixed states transformations in the whole system and obtain the necessary and sufficient conditions on the existence of the desired maps. We expect our work will be helpful to explore what we can do on a finite set of input states.
description: 7 pages
Deconfinement Phase Transition in the $SU(3)$ Instanton-dyon Ensemble
Creators: name: DeMartini, Dallas
name: Shuryak, Edward
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Confinement remains one the most interesting and challenging nonperturbative phenomenon in non-Abelian gauge theories. Recent semiclassical (for SU(2)) and lattice (for QCD) studies have suggested that confinement arises from interactions of statistical ensembles of instanton-dyons with the Polyakov loop. In this work, we extend studies of semiclassical ensemble of dyons to the $SU(3)$ Yang-Mills theory. We find that such interactions do generate the expected first-order deconfinement phase transition. The properties of the ensemble, including correlations and topological susceptibility, are studied over a range of temperatures above and below $T_c$. Additionally, the dyon ensemble is studied in the Yang-Mills theory containing an extra trace-deformation term. It is shown that such a term can cause the theory to remain confined and even retain the same topological observables at high temperatures.
description: 18 pages, 18 figures
The effect of environment on AGN activity: the properties of radio and optical AGN in void, isolated and group galaxies
Creators: name: Miraghaei, Halime
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The evolution of galaxies depends on their environments. In this work, active galactic nucleus (AGN) activity in different environments has been studied. The fractions of radio and optical AGN in four different environments have been compared using samples of void, isolated, group member, and the brightest group galaxies (BGGs). Galaxies in voids show significantly lower stellar ages, concentrations, colours and surface mass densities, and they experience more one-on-one interactions compared to the isolated galaxies and galaxies in groups. In order to study pure environmental effects, the biases caused by the stellar mass and galaxy type quantified by 4000$Å$ break strength have been removed. While the results confirm no dependence of the optical AGN activity on environment in blue galaxies and with lower significance in green galaxies, a higher fraction of optical AGN has been observed for the massive red galaxies in voids compared to the galaxies in dense environments. This may be related to the higher amount of one-on-one interaction observed in the void galaxies, or it may reflect more fundamental differences in the host galaxies or environments of the voids. The radio-mode AGN activity increases in dense environment for red galaxies. No changes in the radio-loud AGN fraction have been observed for the blue and green galaxies. This shows that the effect of environment on AGN activity is not significant in the presence of cold gas in galaxies. We also discuss whether the efficiency of gas accretion depends on the properties of the host galaxy.
description: The Astronomical Journal, 160, 227, (2020)
Long noncoding RNA PR11-387H17.6 as a potential novel diagnostic biomarker of atherosclerotic renal artery stenosis
Creators: name: Fu, Wenxia
name: Tian, Xiaoxiang
name: Liu, Liwen
name: Zhang, Xiaolin
name: Wang, Xiaozeng
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Biochemistry
subject: Space Science
subject: Medicine
subject: Cell Biology
subject: Pharmacology
subject: Immunology
subject: FOS: Clinical medicine
subject: Biological Sciences not elsewhere classified
subject: Marine Biology
subject: Hematology

description: Atherosclerotic renal artery stenosis (ARAS) is frequently related to ischemic nephropathy, secondary hypertension, and end-stage renal failure. Thus, this study aimed to explore whether certain circulating long noncoding RNAs (lncRNAs) may be used as potential specific ARAS biomarkers. In the present study, a microarray analysis was performed to screen for lncRNAs in renal artery tissue from four ARAS patients and four non-ARAS individuals. To identify specific lncRNAs as candidate potential biomarkers of ARAS, we used the following criteria: the fold change was set to >3.0 (compared with non-ARAS tissues), and p value cutoff was set at .05. According to these criteria, six lncRNAs were identified from 1150 lncRNAs. After validation by quantitative PCR (qPCR), these lncRNAs were independently validated in blood from groups of 18 ARAS patients, 18 non-ARAS individuals, and 18 healthy volunteers, furthermore, the predictive value of lncRNA PR11-387H17.6 was further assessed using blood from groups of 99 ARAS patients, 49 non-ARAS individuals, and 50 healthy volunteers. A receiver operating characteristic (ROC) curve analysis was performed to assess the performance of these lncRNAs as biomarkers. In the ROC analysis, the area under the curve (AUC) of PR11-387H17.6 was 0.733, with 52.5% sensitivity and 84.8% specificity in predicting the occurrence of ARAS. After considering the risk factors, the AUC of PR11-387H17.6 was 0.844, and the optimal sensitivity increased from 52.5% to 74.5%, although the specificity decreased from 84.8% to 81.9%. In the multivariable logistic analysis, PR11-387H17.6 was an independent predictor of major adverse events (OR: 3.039; 95% CI: 1.388–6.654; p= .006). PR11-387H17.6 is a potential diagnostic biomarker of ARAS. The lncRNA levels in blood cells are regulated in ARAS. Thus, further investigations of the role of lncRNAs in ARAS are warranted.
Περιοδικότητες σε χρονοσειρές: θεωρητική προσέγγιση και εφαρμογές
Creators: name: Σαμαρά, Ευγενία Διονυσίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2016
Subjects: Χρονοσειρά
Περιοδικότητα
Κινητός μέσος όρος
Time series
Periodicity
Moving average

description: Μοτίβα τα οποία επαναλαμβάνονται με κάποιο συγκεκριμένο τρόπο παρουσιάζουν ιδιαίτερο ενδιαφέρον και συχνά μελετάται η συμπεριφορά τους στο πέρασμα του χρόνου. Τέτοιου είδους μοτίβα ονομάζονται περιοδικά και απαντώνται τόσο στη φύση όσο και στην κοινωνία και την οικονομία. Στην παρούσα διπλωματική εργασία πραγματοποιείται μελέτη διαδοχικών τιμών που παρουσιάζουν περιοδικότητα καθώς εξελίσσονται στο χρόνο, δηλαδή πραγματοποιείται μελέτη περιοδικών χρονοσειρών. Στόχος είναι η εύρεση του περιοδικού στοιχείου με τη χρήση Συστηματικής Δειγματοληψίας και στη συνέχεια η εξομάλυνση του με χρήση κατάλληλου βήματος κινητού μέσου όρου. Επιτυγχάνεται έτσι μια καλύτερη παρουσίαση της πορείας των υπό μελέτης τιμών. Εξετάζεται επιπλέον η ανθεκτικότητα χρονοσειρών ως προς την περιοδικότητα μετά την αφαίρεση κάποιων όρων τους με τυχαίο τρόπο. Από τα αποτελέσματα της παραπάνω μελέτης μπορεί να διαπιστωθεί αρχικά ότι η καλύτερη δυνατή εξομάλυνση μιας περιοδικής χρονοσειράς υλοποιείται με τη χρήση βήματος κινητού μέσου όρου πολλαπλάσιου της περιόδου. Διαπιστώνεται επιπλέον ότι η περιοδικότητα των στοιχείων υιοθετείται και από μέτρα μεταβλητότητας και ότι, τέλος, η προέλευση μιας σειράς δεδομένων από περιοδική χρονοσειρά είναι σχεδόν πάντα διακριτή.
description: Patterns which are repeated with a certain way are of special interest and their behavior over time is often studied. Such patterns are called periodic and occur in nature, in society and to the economy. To this thesis, successive values which present periodicity, as evolving in time, are studied, i.e. periodic time series are studied. The aim of this thesis is to mine periodicities from time series by using a method, which is based on systematic sampling procedures. Simple Moving Average is used in order to smooth periodicities and to achieve a better presentation of time series evolution. Furthermore, after some elements have been randomly removed, time series resistance on periodicity is examined. From the results of the above study, it may be determined that the optimum smoothing of a periodic time series is implemented by using simple moving average with step k, where k is multiple of periodicity. It is also ascertained that the periodicity of the elements is adopted by variation measures. Finally, it is concluded that the origin of data series from a periodic time series is almost always distinct.
Qualitative chirality effects on the Casimir-Lifshitz torque with liquid crystals
Creators: name: Broer, Wijnand
name: Lu, Bing-Sui
name: Podgornik, Rudolf
Publisher: name: arXiv
Year: 2021
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We model a cholesteric liquid crystal as a planar uniaxial multilayer system, where the orientation of each layer differs slightly from that of the adjacent one. This allows us to analytically simplify the otherwise acutely complicated calculation of the Casimir-Lifshitz torque. Numerical results differ appreciably from the case of nematic liquid crystals, which can be treated like bloc birefringent media. In particular, we find that the torque deviates considerably from its usual sinusoidal behavior as a function of the misalignment angle. In the case of a birefringent crystal faced with a cholesteric liquid one, the Casimir-Lifshitz torque decreases more slowly as a function of distance than in the nematic case. In the case of two cholesteric liquid crystals, either in the homochiral or in the heterochiral configuration, the angular dependence changes qualitatively as a function of distance. In all considered cases, finite pitch length effects are most pronounced at distances of about 10 nm.