cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Entangled three-qubit states without concurrence and three-tangle
Creators: name: Lohmayer, Robert
name: Osterloh, Andreas
name: Siewert, Jens
name: Uhlmann, Armin
Publisher: name: arXiv
Year: 2006
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We provide a complete analysis of mixed three-qubit states composed of a GHZ state and a W state orthogonal to the former. We present optimal decompositions and convex roofs for the three-tangle. Further, we provide an analytical method to decide whether or not an arbitrary rank-2 state of three qubits has vanishing three-tangle. These results highlight intriguing differences compared to the properties of two-qubit mixed states, and may serve as a quantitative reference for future studies of entanglement in multipartite mixed states. By studying the Coffman-Kundu-Wootters inequality we find that, while the amounts of inequivalent entanglement types strictly add up for pure states, this ``monogamy'' can be lifted for mixed states by virtue of vanishing tangle measures.
description: 10 RevTeX pages, 3 figures, abstract and conclusions substantially extended
An Analysis of Control Parameters of MOEA/D Under Two Different Optimization Scenarios
Creators: name: Tanabe, Ryoji
name: Ishibuchi, Hisao
Publisher: name: arXiv
Year: 2020
Subjects: subject: Neural and Evolutionary Computing (cs.NE)
subject: FOS: Computer and information sciences

description: An unbounded external archive (UEA), which stores all nondominated solutions found during the search process, is frequently used to evaluate the performance of multi-objective evolutionary algorithms (MOEAs) in recent studies. A recent benchmarking study also shows that decomposition-based MOEA (MOEA/D) is competitive with state-of-the-art MOEAs when the UEA is incorporated into MOEA/D. However, a parameter study of MOEA/D using the UEA has not yet been performed. Thus, it is unclear how control parameter settings influence the performance of MOEA/D with the UEA. In this paper, we present an analysis of control parameters of MOEA/D under two performance evaluation scenarios. One is a final population scenario where the performance assessment of MOEAs is performed based on all nondominated solutions in the final population, and the other is a reduced UEA scenario where it is based on a pre-specified number of selected nondominated solutions from the UEA. Control parameters of MOEA/D investigated in this paper include the population size, scalarizing functions, and the penalty parameter of the penalty-based boundary intersection (PBI) function. Experimental results indicate that suitable settings of the three control parameters significantly depend on the choice of an optimization scenario. We also analyze the reason why the best parameter setting is totally different for each scenario.
description: This is an accepted version of a paper published in Applied Soft Computing
Cancellation/reduction and measurements of some impairments in cable television pictures
Creators: name: Lau, Jose Alberto
Publisher: name: University of British Columbia
Year: 2009

description: As technology improves, customers' expectations become higher every day. With such technologies as the Super-VHS video recording and laserdisc player, customers compare these against the quality of the video received over the cable system. Distortions in the image are mainly caused by the nonlinearity of the underground cascaded amplifiers in the cable TV system. Moreover, the addition of new channels on the congested transmission system will increase present interference levels or create new interferences causing picture quality degradation. There are two approaches for combatting impairments. First, these can be prevented by modifying hardware components in the cable TV system such as amplifiers, converters among others. The other approach is to deal with the distortion itself through the use of image processing and filtering techniques. The idea of this approach is, if not to totally cancel the distortion, to reduce it until it becomes less visible to the human eye. This thesis deals with the second approach that consists of reducing/cancelling and measuring impairments such as the single frequency intermodulation, narrowband and wideband CSO (Composite Second Order) distortion. This would complement the automatic detection for a complete monitoring process of impairments. Our approach would fit in an automatic system since it employs non-intrusive methods that do not involve the use of a test signal and hence, no interruption in the transmission would be needed. In this thesis, several filtering methods for cancellation and reduction of single frequency intermodulation, narrowband and wideband CSO are studied and compared. Among these methods are the FIR Linear Filtering, Interpolation in the frequency domain and the Alpha Trimmed Filter. Results show that a combination of the last two methods reduces the single frequency intermodulation considerably. In addition, results also show that the interpolation in the frequency domain perform better than the other methods for narrowband CSO cancellation and reduction. In the case of wideband CSO, a combination of the interpolation in the frequency domain and the Alpha Trimmed filter reduces the impairment considerably. In the area of SNR measurements, different algorithms are proposed for each impairment. For the single frequency intermodulation, the interpolation in the frequency domain algorithm provides acceptable SNR measurements of less than 0.5 dB margin error. For the narrowband CSO, algorithms consisting of the interpolation in the frequency domain and the block averaging are proposed. These two algorithms provide acceptable results. For the wideband CSO, several algorithms that involve the one-dimensional and two-dimensional Discrete Fourier transform are proposed. The two-dimensional algorithms provide more accurate results than the one-dimensional approach giving a margin error of less than 2 dB for SNR measurements of up to 53 dB.
CP asymmetries of B to phi K_S and B to eta' K_S in SUSY GUT Model with Non-universal Sfermion Masses
Creators: name: Kim, S. -G.
name: Maekawa, N.
name: Matsuzaki, A.
name: Sakurai, K.
name: Yoshikawa, T.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We analyze CP asymmetries of B \to ϕK_S and B \to η' K_S in a supersymmetric grand unified theory in which only the third generation sfermions contained in 10(Q, U^c, E^c) of SU(5) can have a different mass from the others. One of the advantages of this nonuniversal mass model is that the first two generation sfermion masses can be large whereas both (left and right handed) stops are light so as to stabilize the weak scale. Therefore, we studied a minimal supersymmetric standard model parameter region in which a fine tuning in Higgs sector is relaxed owing to light masses of stops, gluino and higgsinos. In such a parameter region, the chargino contribution is as important as the gluino one. We show that the CP asymmetries of B \to ϕK_S and B \to η' K_S can deviate from their standard model predicted values by O(0.1) because of constructive interference between gluino and chargino contributions.
description: 22 pages, 5 figures
Full background decomposition of the CONUS experiment
Creators: name: Bonet, H.
name: Bonhomme, A.
name: Buck, C.
name: Fülber, K.
name: Hakenmüller, J.
name: Hempfling, J.
name: Heusser, G.
name: Hugle, T.
name: Lindner, M.
name: Maneschg, W.
name: Rink, T.
name: Strecker, H.
name: Wink, R.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: The CONUS experiment is searching for coherent elastic neutrino nucleus scattering of reactor anti-neutrinos with four low energy threshold point-contact high-purity germanium spectrometers. An excellent background suppression within the region of interest below 1keV (ionization energy) is absolutely necessary to enable a signal detection. The collected data also make it possible to set limits on various models regarding beyond the standard model physics. These analyses benefit as well from the low background level of ~10d$^{-1}$kg$^{-1}$below 1keV and at higher energies. The low background level is achieved by employing a compact shell-like shield, that was adapted to the most relevant background sources at the shallow depth location of the experiment: environmental gamma-radiation and muon-induced secondaries. Overall, the compact CONUS shield including the active anti-coincidence muon-veto reduces the background by more than four orders of magnitude. The remaining background is described with validated Monte Carlo simulations which include the detector response. It is the first time that a full background decomposition in germanium operated at reactor-site has been achieved. Next to remaining muon-induced background, $^{210}$Pb within the shield and cryostat end caps, cosmogenic activation and air-borne radon are the most relevant background sources. The reactor-correlated background is negligible within the shield. The validated background model together with the parameterization of the noise are used as input to the likelihood analyses of the various physics cases.
description: 27 pages, 21 figures
Αποκωδικοποίηση της μη λεκτικής συμπεριφοράς του εκπαιδευτικού από μαθητές του δημοτικού σχολείου
Creators: name: Βρεττός, Γιάννης Ε.
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1996

description: Ziel der vorliegenden Untersuchung ist es zu beweisen, dass die Schueler das nichtverbale Verhalten derjenigen Lehramtsstudierenden trefflicher entschluesseln koennen, die in dieser Lehrfertigkeit geuebt sind. Im Rahmen der Untersuchung haben 56 Schueler der dritten und 62 der fuenften Klasse der griechischen Volksschule anhand eines Beobachtungsbogens das nichtverbale Verhalten von Lehramtsstudie-renden zu dekodieren versucht. Es wurde festgestellt, dass aeltere Schueler die nonverbalen Lehrersignale besser wahrnehmen koennen als juengere. Ethielt das nichtverbaie Verhalten der trainierten Lehramtsstudierenden sich konvergierende Elemente, erkannten die Schueler die Bedeutung r meisten nichtverbalen Signale relativ leicht. Lagen jedoch in sich 'ergierende nichtverbaie Elemente vor, also auch widersprüchliche Mitteilungen, so war die Verwirrung bei den Schuelern unverkennbar. Es wurde weiter bewiesen, dass die Interaktionsmuster in der Klasse d die Dekodierungsfaehigkeit der Schueler von ihrem Sitzplatz abhaengt, und dass geschlechtsspezifische Unterschiede bei der Interpretation der Koerpersignale des Lehrers eine Rolle spielen.
description: Παιδαγωγική Επιθεώρηση, Vol. 24 (1996)
On the Kirchhoff equation with prescribed mass and general nonlinearities
Creators: name: Zeng, Xiaoyu
name: Zhang, Jianjun
name: Zhang, Yimin
name: Zhong, Xuexiu
Publisher: name: arXiv
Year: 2021
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 35A01, 35B09, 35B40, 35J60

description: In the present paper, we apply a global branch approach to study the existence, non-existence and multiplicity of positive normalized solutions $(λ_c, u_c)\in \mathbb{R}\times H^1(\mathbb{R}^N)$ to the following Kirchhoff problem $$ -\left(a+b\int_{\mathbb{R}^N}|\nabla u|^2dx\right)Δu+λu=g(u)~\hbox{in}~\mathbb{R}^N,\;N\geq 1 $$ satisfying the normalization constraint $
\displaystyle\int_{\mathbb{R}^N}u^2=c, $ which appears in free vibrations of elastic strings. The parameters $a,b>0$ are prescribed as well as the mass $c>0$. Due to the presence of the non-local term $b\int_{\mathbb{R}^N}|\nabla u|^2dx Δu$, such problems lack the mountain pass geometry in the higher dimension case $N\geq 5$. Our result seems to be the first attempt in this aspect.
description: Published in Discrete and Continuous Dynamical Systems - Series S, Vol. 16, No. 11, November 2023, pp. 3394-3409
Observations of the 599 Hz Accreting X-ray Pulsar IGR J00291+5934 during the 2004 Outburst and in Quiescence
Creators: name: Torres, M. A. P.
name: Jonker, P. G.
name: Steeghs, D.
name: Roelofs, G. H. A.
name: Bloom, J. S.
name: Casares, J.
name: Falco, E. E.
name: Garcia, M. R.
name: Marsh, T. R.
name: Mendez, M.
name: Miller, J. M.
name: Nelemans, G.
name: Rodriguez-Gil, P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report on optical and NIR observations obtained during and after the 2004 December discovery outburst of the X-ray transient and accretion-powered millisecond pulsar IGR J00291+5934. Our observations monitored the evolution of the brightness and the spectral properties of J00291 during the outburst decay towards quiescence. We also present optical, NIR and Chandra observations obtained during true quiescence. Photometry of the field during outburst reveals an optical and NIR counterpart that brightened from R~23 to R~17 and from K=19 to K~16. Spectral analysis of the RIJHK broadband photometry shows excess in the NIR bands that may be due to synchrotron emission. The Halpha emission line profile suggests the orbital inclination is ~22-32 degrees. The preferred range for the reddening towards the source is 0.7 < E(B-V) < 0.9, which is equivalent to 4.06E21 cm^-2 < NH < 5.22E21 cm^-2. The Chandra observations of the pulsar in its quiescent state gave an unabsorbed 0.5-10 keV flux for the best-fitting power-law model to the source spectrum of (7.0 +/- 0.9)E-14 ergs/cm^2/s (adopting a hydrogen column of 4.6E21 cm^-2. The fit resulted in a power-law photon index of 2.4 +/- 0.5. The (R-K)o color observed during quiescence supports an irradiated donor star and accretion disk. We estimate a distance of 2 to 4 kpc towards J00291 by using the outburst X-ray light curve and the estimated critical X-ray luminosity necessary to keep the outer parts of the accretion disk ionized. Using the quiescent X-ray luminosity and the spin period, we constrain the magnetic field of the neutron star to be < 3E8 Gauss.
description: 10 pages, 7 figures, 3 tables. Revision both in text and figures to match the accepted manuscript to appear in ApJ
Spin Dynamics in a Tunnel Junction between Ferromagnets
Creators: name: Fransson, J.
name: Zhu, Jian-Xin
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The dynamics of a single spin embedded in the tunnel junction (quantum point contact) between ferromagnets is addressed. Using the Keldysh technique, we derive a quantum Langevin equation. As a consequence of the spin-polarization in the leads, the spin displays a rich and unusual dynamics. Parallel configured and equally strong magnetic moments in the leads yield an ordinary spin precession with a Larmor frequency given by the effective magnetic field. Unequal and/or non-parallel configured magnetization, however, causes nutation of the spin in addition to the precession. Our predictions may be directly tested for macroscopic spin clusters.
description: 5 pages, 1 figure, accepted in the New Journal of Physics
Twisted Gauge Theories
Creators: name: Aschieri, Paolo
name: Dimitrijevic, Marija
name: Meyer, Frank
name: Schraml, Stefan
name: Wess, Julius
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Gauge theories on a space-time that is deformed by the Moyal-Weyl product are constructed by twisting the coproduct for gauge transformations. This way a deformed Leibniz rule is obtained, which is used to construct gauge invariant quantities. The connection will be enveloping algebra valued in a particular representation of the Lie algebra. This gives rise to additional fields, which couple only weakly via the deformation parameter and reduce in the commutative limit to free fields. Consistent field equations that lead to conservation laws are derived and some properties of such theories are discussed.
description: 11 pages, V2: details and appendix added
Ενδυναμωτική Ηγεσία και Καινοτόμα Εργασιακή Συμπεριφορά: Ο διαμεσολαβητικός ρόλος του εργασιακού πάθους
Creators: name: Βουλγαράκης, Χαράλαμπος Χρήστου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Ενδυναμωτική ηγεσία
Εργασιακό αρμονικό πάθος
Καινοτόμα εργασιακή συμπεριφορά
Empowering leadership
Ηarmonious passion
Ιnnovating work behavior

description: Σκοπός της παρούσας διπλωματικής εργασίας είναι να μελετήσει την έννοια της ενδυναμωτικής ηγεσίας στο πλαίσιο των δημόσιων σχολικών μονάδων της δευτεροβάθμιας εκπαίδευσης. Η ενδυναμωτική ηγεσία, η οποία σχετίζεται με την εκχώρηση μέρους της εξουσίας του διευθυντή στον σύλλογο διδασκόντων, έχει αποδειχθεί ότι επηρεάζει θετικά την εργασιακή συμπεριφορά των εργαζομένων ενισχύοντας το αίσθημα της αυτο-αποτελεσματικότητας. Η συγκεκριμένη εργασία μελετά τις επιπτώσεις της ενδυναμωτικής ηγεσίας στην καινοτόμα συμπεριφορά των εκπαιδευτικών και τον διαμεσολαβητικό ρόλο του εργασιακού αρμονικού πάθους, το οποίο συνίσταται από την ηθελημένη εσωτερίκευση της προσπάθειας για την εκτέλεση μιας δραστηριότητας και από την ταύτιση του εργαζομένου με τη συγκεκριμένη δραστηριότητα. Στο πλαίσιο της εργασίας πραγματοποιήθηκε εμπειρική έρευνα με τη χρήση ερωτηματολόγιου αυτο-αναφοράς σε 167 εν ενεργεία εκπαιδευτικούς ανά την ελληνική επικράτεια. Τα αποτελέσματα της έρευνας υποστηρίζουν ότι η ενδυναμωτική ηγεσία που ασκείται από τον διευθυντή έχει ως αποτέλεσμα την εκδήλωση αρμονικού πάθους από πλευράς των εκπαιδευτικών, γεγονός που οδηγεί στην καινοτόμα εργασιακή συμπεριφορά. Τέλος, προτείνονται χρήσιμες πρακτικές στα στελέχη εκπαίδευσης αναφορικά με τους τρόπους ενδυνάμωσης των εκπαιδευτικών και επισημαίνονται οι περιορισμοί της έρευνας και προτάσεις για τη μελλοντική επέκτασή της.
description: The aim of the thesis is to study the construct of empowering leadership within the framework of Greek public schools of secondary education. The empowering leadership affects in a positive way the teacher’s working behavior when the principal delegates authority to the teaching members. The present thesis inquires the impact of empowering leadership on teacher’s innovating work behavior and the mediating role of harmonious passion. The harmonious passion leads individuals to choose to be engaged in activities through autonomous internalization. In this context, an empirical research on 167 teachers across Greek schools has been conducted through a self-reporting questionnaire. The findings suggest that when empowering leadership is related to harmonious passion triggers teacher’s innovating behavior. Finally, practical implications for school principals are suggested and the research limitations and expansions are pointed.
Το δεδικασμένο των αποφάσεων των διοικητικών δικαστηρίων
Creators: name: Κυριαζόπουλος, Αχιλλέας Χρήστου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Δεδικασμένο
Διοικητικά δικαστήρια
Διοικητικό δικονομικό δίκαιο
Res judicata
Administrative courts
Administrative procedural law

description: Ο θεσμός του δεδικασμένου συναντάται σε όλους τους δικαιοδοτικούς κλάδους και εξυπηρετεί την παροχή αποτελεσματικής δικαστικής προστασίας. Στη διοικητική δικαιοσύνη το δεδικασμένο των δικαστικών αποφάσεων καλύπτει το “διοικητικής φύσεως ζήτημα”, το οποίο αποτελεί ουσιαστικά το συμπέρασμα της δικανικής κρίσης, αναπόσπαστα συνδεδεμένο με τις προκείμενες που αποτελούν το απαραίτητο στήριγμά του. Αναπτύσσει την ισχύ του μεταξύ των διαδίκων που μετείχαν στην δίκη, ενώ σε εξαιρετικές μόνο περιπτώσεις προβλέπεται η επέκτασή του σε τρίτα πρόσωπα που συνδέονται στενά με τους διαδίκους. Δεσμεύει τόσο τον δικαστή, όσο και τη διοίκηση, που οφείλουν να σέβονται όσα κρίθηκαν με ισχύ δεδικασμένου. Η ανατροπή του δεδικασμένου φαίνεται να είναι ασύμβατη με την ίδια τη φύση του. Εντούτοις, η εμφάνιση νέων πραγματικών ή νομικών στοιχείων καθώς και η άσκηση ενδίκων μέσων εμποδίζουν την επέλευση των συνεπειών του. Τέλος, αν και παρουσιάζει στενή συγγένεια με άλλους θεσμούς του διοικητικού δικαίου, όπως η erga omnes ακύρωση των παράνομων διοικητικών πράξεων και η υποχρέωση συμμόρφωσης της διοίκησης προς τις δικαστικές αποφάσεις, διακρίνεται σαφώς από αυτούς.
description: Res judicata is a common principle in all jurisdictions and it serves the effective judicial protection. Res judicata for administrative courts’ decisions covers the “issue of administrative nature”, which is essentially the conclusion of the judge’s syllogism, and cannot be separated from the reasons onto which is founded. It constrains the litigants, who participated in the process, but in exceptional cases, it may be extended to third parties closely related to the litigants. Both the judges and the administrative authorities are obliged to respect res judicata. Reversing res judicata seems to be incompatible with the nature of this principle. However, new facts and legal issues, as well as the acceptance of legal remedies, prevents the effects of res judicata. Finally, although it is closely related to other administrative law principles, such as the erga omnes annulment of the illegal administrative decisions and the compliance obligation of the administration judgments, res judicata is clearly distinguished from them.
Το ζήτημα της εκλεκτικής καισαρικής τομής και οι βιοηθικές προεκτάσεις του
Creators: name: Χαρίση, Αφροδίτη Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Καισαρική τομή
Μητρική απαίτηση
Βιοηθική
Caesarean delivery
Maternal request
Bioethics

description: Σε πολλά επιστημονικά άρθρα, γίνεται λόγος για τον συνεχώς αυξανόμενο αριθμό γυναικών που επιλέγουν να υποβληθούν σε καισαρική τομή χωρίς να υπάρχει ιατρική αναγκαιότητα. Η παρούσα εργασία διερευνά αν η επιλογή της καισαρικής τομής, κατόπιν μητρικής απαίτησης, μπορεί να θεμελιωθεί ηθικά στην αυτονομία του ασθενή, και αναδεικνύει εάν η επιλογή αυτή είναι μια πραγματικά αυτόνομη επιλογή ή επηρεασμένη από κοινωνικές επιρροές. O ελληνικός Κώδικας Ιατρικής Δεοντολογίας, αν και δεν καλύπτει την περίπτωση της καισαρικής τομής χωρίς ιατρική ένδειξη, εντούτοις, αναφέρει εκτενώς τις προϋποθέσεις που πρέπει να πληρούνται προκειμένου να καθίσταται έγκυρη η συναίνεση του ενημερωμένου ασθενή. Ο γιατρός πρέπει να τηρεί τις ηθικές αρχές που αναδεικνύει η βιοηθική, με έμφαση στην αρχή της ενήμερης συγκατάθεσης, ώστε να βοηθήσει την έγκυο να κάνει μια ελεύθερη και αυτόνομη επιλογή.
description: Many scientific articles, make comments on the increasing number of women who choose to undergo cesarean section without medical necessity. This study examines the ethics of caesarean section, at the request of the mother, using terms that define the autonomy of the patient, and if this choice is truly independent or influenced by social influences. The Greek medical ethics code does not justify the caesarean section without medical indication, however, indicate the conditions that should apply in order to become valid, the consent of an informed patient. The doctor must respect the ethical principles of bioethics, especially the principle of informed consent of the patient, to help the pregnant make a truly free and independent choice.
Constructing near-embeddings of codimension one manifolds with countable dense singular sets
Creators: name: Repovš, D.
name: Rosicki, W.
name: Zastrow, A.
name: Željko, M.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Geometric Topology (math.GT)
subject: General Topology (math.GN)
subject: FOS: Mathematics
subject: 57Q55; 57N35; 54B15; 57N60

description: The purpose of this paper is to present, for all $n\ge 3$, very simple examples of continuous maps $f:M^{n-1} \to M^{n}$ from closed $(n-1)$-manifolds $M^{n-1}$ into closed $n$-manifold $M^n$ such that even though the singular set $S(f)$ of $f$ is countable and dense, the map $f$ can nevertheless be approximated by an embedding, i.e. $f$ is a {\sl near-embedding}.
Detectability of the gravitational-wave background produced by magnetar giant flares
Creators: name: Kouvatsos, Nikolaos
name: Lasky, Paul D.
name: Quitzow-James, Ryan
name: Sakellariadou, Mairi
Publisher: name: arXiv
Year: 2022
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the gravitational-wave background produced by f-mode oscillations of neutron stars triggered by magnetar giant flares. For the gravitational-wave energy, we use analytic formulae obtained via general relativistic magnetohydrodynamic simulations of strongly magnetized neutron stars. Assuming the magnetar giant flare rate is proportional to the star-formation rate, we show the gravitational-wave signal is likely undetectable by third-generation detectors such as the Einstein Telescope and Cosmic Explorer. We calculate the minimum value of the magnetic field and the magnetar giant flare rate necessary for such a signal to be detectable, and discuss these in the context of our current understanding of magnetar flares throughout the Universe.
description: 7 pages, 3 figures
Η Εξωστρέφεια των Ελληνικών Επιχειρήσεων στο Διάστημα της Κρίσης: Μια Εμπειρική Ανάλυση
Creators: name: Χατζηεφραιμίδου, Μυρτώ Πρόδρομου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Εξωστρέφεια
Μέθοδοι Ελαχίστων Τετραγώνων
Εισηγμένες Εταιρείες
International Business
Method of least squares
Stock Exchange Companies

description: Σκοπός της εργασίας είναι να εξετάσει την εξαγωγική συμπεριφορά των Ελληνικών εταιρειών. Το πρώτο κομμάτι της εργασίας αφορά το θεωρητικό υπόβαθρο των εννοιών εξωστρέφεια και εξαγωγές. Αρχικά, αναφερόμαστε στις βασικές θεωρίες διεθνούς εμπορίου και στην εξέλιξή τους. Έπειτα παρουσιάζουμε την βιβλιογραφική επισκόπησης της έννοιας των εξαγωγών και αναφερόμαστε στα εμπόδια και τα κίνητρα τους. Το επόμενο κομμάτι της εργασίας είναι το εμπειρικό σκέλος της. Συγκεκριμένα, αρχικά παρουσιάζουμε τα δεδομένα μας. Τα δεδομένα μας είναι της μορφής πάνελ, έχοντας 80 εταιρείες και η χρονική διάρκεια του δείγματος της κάθε εταιρείας είναι πέντε έτη. Επιπλέον, βλέπουμε πως καμία από τις μεταβλητές μας δεν ακολουθεί κανονική κατανομή. Έπειτα περνάμε στην μεθοδολογία στην οποία παρουσιάζονται τρεις μέθοδοι γραμμικής παλινδρόμησης, η απλή, η γενικευμένη και η σταθμισμένη. Επειδή τα δεδομένα μας εμφανίσουν μεγάλη μεταβλητότητα, θεωρούμε ότι η μέθοδος που θα εφαρμόσει καλύτερα στα δεδομένα μας είναι η σταθμισμένη. Κάτι το οποίο επιβεβαιώνεται και από τα αποτελέσματα. Συγκεκριμένα, με τις δύο πρώτες μεθόδους δεν ανιχνεύουμε σχεδόν καμία στατιστικά σημαντική σχέση, ενώ αντίθετα με την WLS οι περισσότερες μεταβλητές μας φαίνεται να επηρεάζουν σημαντικά την ενδογενή μεταβλητή.
description: Aim of this study is to examine the export behavior of Greek companies. The first part of this paper concerns the theoretical background of extroversity and exports concepts. Initially, we refer to international trade theories and their evolution. Then we present the literature review of the concept of exports and refer to the obstacles and the incentives. The next part of this thesis is the empirical one. Specifically, first we present our data. Our data are formed as panel data, having 80 companies and the duration of the sample of each company is five years. Moreover, we see that none of our variables do not follow a normal distribution. In the methodology are presented three methods of linear regression, simple (OLS), generalized (GLS) and weighted (WLS). Because our data show considerable volatility, we believe that the method that will apply best to our data is the weighted one. Something which is confirmed by the results. Specifically, the first two methods do not detect almost no significant relationship, while with the WLS most of our variables appear to significantly affect the endogenous variable.
Η ΕΣΔΑ και η εφαρμογή της στην ελληνική νομολογία, μέσα από το παράδειγμα του ΣτΕ 2001-2013
Creators: name: Ρουμελιώτη, Θεοδώρα Γεωργίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: ΕΣΔΑ
ΣτΕ
Νομολογία
ECHR
Council of State
Jurisprudence

description: Η παρούσα μελέτη πραγματεύεται την εφαρμογή και την αξιοποίηση της Ευρωπαϊκής Σύμβασης των Δικαιωμάτων του Ανθρώπου (ΕΣΔΑ) στην ελληνική νομολογία, όπως αυτή αποτυπώθηκε μέσα από τη νομολογία του Συμβουλίου της Επικρατείας (ΣτΕ) το χρονικό διάστημα 2001-2013. Δεδομένου ότι η ΕΣΔΑ αποτελεί μέρος του ελληνικού εσωτερικού δικαίου και ερμηνεύεται από τα αρμόδια όργανα του κράτους, τίθεται το ερώτημα του κατά πόσον ο δικαστής του ΣτΕ, ως φυσικός δικαστής της ΕΣΔΑ, έχει ανταποκριθεί στο ρόλο του ως ο κατεξοχήν εφαρμοστής της Σύμβασης. Το πρώτο μέρος της μελέτης περιλαμβάνει μια σύντομη ιστορική αναφορά στο θεσμικό πλαίσιο της προστασίας των δικαιωμάτων του ανθρώπου καθώς και το θεωρητικό πλαίσιο που διέπει την ΕΣΔΑ (προστατευόμενα δικαιώματα και ελευθερίες, αρχές που διέπουν την εφαρμογή της). Το δεύτερο μέρος που αποτελεί και το βασικό αντικείμενο της έρευνας περιλαμβάνει την επεξεργασία των νομολογιακών στοιχείων και δεδομένων που αφορούν την εφαρμογή και αξιοποίηση της ΕΣΔΑ, όπως αυτά προέκυψαν από τη συλλογή των αποφάσεων του ΣτΕ κατά την προαναφερόμενη χρονική περίοδο. Τέλος στο τρίτο μέρος παρουσιάζεται η αξιολόγηση των νομολογιακών δεδομένων και η εξαγωγή ορισμένων βασικών συμπερασμάτων, όπως αυτά προέκυψαν μέσα από τη νομολογιακή επεξεργασία, τα οποία και προηγούνται των καταληκτικών παρατηρήσεων.
description: The present study has as object the application and enhancement of the European Convention of Human Rights (ECHR) in greek jurisprudence, as reflected through the jurisprudence of the Council of State, the period from 2001 to 2013. Considering that the ECHR is part of the greek national law and is interpreted by the competent organs of the state, the question arises whether the judge of the Council of the State, as the natural judge of the ECHR, has met in his role as the main applier of the Convention. The first part of the study includes a brief historical reference in the institutional framework of the protection of human rights as well as the theoretical framework underlying the ECHR (protected rights and freedoms, principles governing the implementation). The second part, which is the main object of the research involves the processing of jurisprudential information and data relating to the application and utilization of the ECHR, such as those resulting from the collection of judgments of the Council of State during the period that is mentioned before. Finally in the third part is shown the evaluation of jurisprudential data and the export of some key findings as they emerged through jurisprudential treatment, which they precede the concluding observations.
Decoherence of domains and defects at phase transitions
Creators: name: Lombardo, F. C.
name: Rivers, R. J.
name: Villar, P. I.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: Other Condensed Matter (cond-mat.other)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: In this further letter on the onset of classical behaviour in field theory due to a phase transition, we show that it can be phrased easily in terms of the decoherence functional, without having to use the master equation. To demonstrate this, we consider the decohering effects due to the displacement of domain boundaries, with implications for the displacement of defects, in general. We see that decoherence arises so quickly in this event, that it is negligible in comparison to decoherence due to field fluctuations in the way defined in our previous papers.
description: Version published in Phys. Lett. B
Protocols for optimal readout of qubits using a continuous quantum nondemolition measurement
Creators: name: Gambetta, Jay
name: Braff, W. A.
name: Wallraff, A.
name: Girvin, S. M.
name: Schoelkopf, R. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We study how the spontaneous relaxation of a qubit affects a continuous quantum non-demolition measurement of the initial state of the qubit. Given some noisy measurement record $Ψ$, we seek an estimate of whether the qubit was initially in the ground or excited state. We investigate four different measurement protocols, three of which use a linear filter (with different weighting factors) and a fourth which uses a full non-linear filter that gives the theoretically optimal estimate of the initial state of the qubit. We find that relaxation of the qubit at rate $1/T_1$ strongly influences the fidelity of any measurement protocol. To avoid errors due to this decay, the measurement must be completed in a time that decrease linearly with the desired fidelity while maintaining an adequate signal to noise ratio. We find that for the non-linear filter the predicted fidelity, as expected, is always better than the linear filters and that the fidelity is a monotone increasing function of the measurement time. For example, to achieve a fidelity of 90%, the box car linear filter requires a signal to noise ratio of $\sim 30$ in a time $T_1$ whereas the non-linear filter only requires a signal to noise ratio of $\sim 18$.
description: 12 pages, 6 figures
A simulation-free seismic survey design by maximizing the spectral gap
Creators: name: Zhang, Yijun
name: Louboutin, Mathias
name: Siahkoohi, Ali
name: Yin, Ziyi
name: Kumar, Rajiv
name: Herrmann, Felix J.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Spectral Theory (math.SP)
subject: Geophysics (physics.geo-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: Due to the tremendous cost of seismic data acquisition, methods have been developed to reduce the amount of data acquired by designing optimal missing trace reconstruction algorithms. These technologies are designed to record as little data as possible in the field, while providing accurate wavefield reconstruction in the areas of the survey that are not recorded. This is achieved by designing randomized subsampling masks that allow for accurate wavefield reconstruction via matrix completion methods. Motivated by these recent results, we propose a simulation-free seismic survey design that aims at improving the quality of a given randomized subsampling using a simulated annealing algorithm that iteratively increases the spectral gap of the subsampling mask, a property recently linked to the quality of the reconstruction. We demonstrate that our proposed method improves the data reconstruction quality for a fixed subsampling rate on a realistic synthetic dataset.
Identification of radiopure tungsten for low background applications
Creators: name: Hakenmüller, J.
name: Maneschg, W.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: In this article we explore the availability of radiopure tungsten and its potential as high density shield material for low background applications. For compact shield designs, conventionally, lead is used. Metallic tungsten and tungsten pseudo-alloys reach higher densities up to 19.3 gcm$^{-3}$ and do not exhibit a significant $^{210}$Pb activity, which is a typical intrinsic contamination in lead. Within several $γ$-ray screening campaigns we were able to identify tungsten samples with activities similar or better than 1 mBqkg$^{-1}$ in $^{232}$Th, $^{40}$K, $^{60}$Co and the second part of the $^{238}$U decay chain. In cooperation with a manufacturer we further reduced a persisting contamination in the first part of the $^{238}$U decay chain by a factor of $\sim$2.5 down to (305$\pm$30) mBqkg$^{-1}$. With Monte Carlo simulations, the construction of prototype tungsten-based setups and dedicated measurements, the shield capability of tungsten in comparison to lead was extensively studied. Specifically, the impact of cosmogenic radiation on the background at shallow depth was investigated. We showed that a 6-40% reduction (depending on the exact shield configuration) in the muon-induced neutron fluence is achievable by replacing lead with an equivalent amount of tungsten regarding the suppression of external $γ$-radiation. Overall, many benefits using tungsten especially for low energy applications below a few 100 keV are found. The pseudo-tungsten alloy presented in this work paves the way for several applications especially regarding background suppression in particle and astroparticle physics search programs.
description: 17 pages, 15 figures
Imaging the coupling between itinerant electrons and localised moments in the centrosymmetric skyrmion magnet GdRu2Si2
Creators: name: Yasui, Yuuki
name: Butler, Christopher J.
name: Khanh, Nguyen Duy
name: Hayami, Satoru
name: Nomoto, Takuya
name: Hanaguri, Tetsuo
name: Motome, Yukitoshi
name: Arita, Ryotaro
name: Arima, Taka-hisa
name: Tokura, Yoshinori
name: Seki, Shinichiro
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Magnetic skyrmions were thought to be stabilised only in inversion-symmetry breaking structures, but skyrmion lattices were recently discovered in inversion symmetric Gd-based compounds, spurring questions of the stabilisationmechanism. A natural consequence of a recent theoretical proposal, a coupling between itinerant electrons and localised magnetic moments, is that the skyrmions are amenable to detection using even non-magnetic probes such as spectroscopic-imaging scanning tunnellingmicroscopy (SI-STM). Here SI-STM observations of GdRu$_2$Si$_2$ reveal patterns in the local density of states that indeed vary with the underlying magnetic structures. These patterns are qualitatively reproduced by model calculations which assume exchange coupling between itinerant electrons and localised moments. These findings provide a clue to understand the skyrmion formation mechanism in GdRu$_2$Si$_2$.
description: 21+7 pages, 4+11 figures, to appear in Nature Communications
Οι μισσιοναρικές καταβολές της αμερικανικής εξωτερικής πολιτικής στα νοτιοανατολικά Βαλκάνια το πρώτο τέταρτο του εικοστού αιώνα.
Creators: name: Σπανός, Ζαχαρίας Δημητρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: μισσιονάριοι
Βαλκάνια
Αμερικανική εξωτερική πολιτική
missionaries
Balkans
American foreign policy

description: Η εργασία πραγματεύεται το ζήτημα των μισσιοναρικών καταβολών της αμερικανικής εξωτερικής πολιτικής στα Βαλκάνια την πρώτη 20ετία του 20ου αιώνα. Ως καταβολές νοούνται φυσικές,σε επίπεδο προσώπων, και ιδεολογικές παράμετροι που που επηρέσαν αποφάσεις της εξωτερικής πολιτικής, ενώ ως περιοχή αναφοράς ορίζεται η σημερινή (2015) Ευρωπαϊκή Τουρκία, η Βόρεια Ελλάδα, η Βουλγαρία, η FYROM, η Αλβανία και η Σερβία. Εντοπισμένη σε τέσσερις κυρίως άξονες, αυτούς της οικονομίας, της φιλανθρωπικής δράσης, του προσηλυτισμού και της εκπαίδευσης, η αμερικανική παρουσία εμφανίζει διαφορετικές εντάσεις ανά άξονα και χώρα, αν και συνολικά προτεραιότητα για τους Αμερικανούς ιεραποστόλους φαινόταν αν αποτελεί η Βουλγαρία και δευτερευόντως η Αλβανία. Κριτήριο σε μεγάλο βαθμό αποτελούσε η συγκυρία συνάντησης της μισσιοναρικής δράσης με τον εκάστοτε βαλκανικό εθνικισμό, αν και για την πλήρη εικόνα του θέματος θα πρέπει να ληφθεί υπόψη συνολικά η επίδραση της προτεσταντικής σκέψης στην αμερικανική ταυτότητα, τις πολιτικές αντιλήψεις και φυσικά την εξωτερική πολιτική ενός έθνους που θεωρούσε τον εαυτό του «την τελευταία μεγάλη ελπίδα του κόσμου».
description: The paper deals with the missionary origins of the American foreign policy in the Balkans the first 20 years of the 20th century. As origins are considered physical ,such as persons, and ideological parameters which ,even if they didn’t’ t absolutely formed, they influenced foreign policy decisions. The reference field is today (2015) European Turkey , Northern Greece, Bulgaria, FYROM, Serbia, Albania. The American presence in the area focused in four axons, economy, education, relief and proselytism, presented different levels of activity both per axon and country, although in general it was Bulgaria who seemed to consist priority for the American missionaries with Albania following second. Decisive factor was the timing of meeting between missionary activity and nationalism in each case, although for a wider perspective one must take under consideration the fundamental influence of Protestantism in American identity, political thought and of course in foreign policy of a nation who considered itself “the last great hope on earth”.
Αναπαραστάσεις των εκπαιδευτικών για τα μαθηματικά και τη διδακτική τους
Creators: name: Τρούλης, Γεώργιος Μ.
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1996

description: Quant on pense aux références théoriques qui soutiennent les fondements l’enseignement et d’apprentissage des mathématiques on se limite en trois familles différentes: les références "Platoniciennes", les références "Logistiques" et les références "Constructrvistes". Pour chacune de ces familles on lîstingue cinq types de représentations qui caractérisent les enseignants selon leur appartenance dans l’une ou l'autre famille: la représentation du avoir, la représentation de l’ensegnement, la représentation de l'apprentissage, le statut de V erreur et la fonction de l’observation des productions des élèves et du recueil d’informations. Parmi celles la conception constructiviste convient de plus à l’enseignement des mathématiques à l’école primaire parce qu’elle conçoit le savoir mathématique comme objet réel, l’enseignement comme une nouvelle construction du savoir, l’appre¬ntissage comme un processus long et personnel, l’erreur comme signifiante et la fonction de l’observation des productions des élèves et du recueil d’information comme moyen de révision et d’amélioration de l’enseignement.
description: Παιδαγωγική Επιθεώρηση, Vol. 24 (1996)
Accelerated Magnonic Motional Cooling with Deep Reinforcement Learning
Creators: name: Sarma, Bijita
name: Borah, Sangkha
name: Kani, A
name: Twamley, Jason
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Achieving fast cooling of motional modes is a prerequisite for leveraging such bosonic quanta for high-speed quantum information processing. In this work, we address the aspect of reducing the time limit for cooling below that constrained by the conventional sideband cooling techniques; and propose a scheme to apply deep reinforcement learning (DRL) to achieve this. In particular, we have shown how the scheme can be used effectively to accelerate the dynamic motional cooling of a macroscopic magnonic sphere, and how it can be uniformly extended for more complex systems, for example, a tripartite opto-magno-mechanical system to obtain cooling of the motional mode below the time bound of coherent cooling. While conventional sideband cooling methods do not work beyond the well-known rotating wave approximation (RWA) regimes, our proposed DRL scheme can be applied uniformly to regimes operating within and beyond the RWA, and thus this offers a new and complete toolkit for rapid control and generation of macroscopic quantum states for application in quantum technologies.
description: 15 pages, 10 figures (including supplemental material)
Split String Formalism and the Closed String Vacuum
Creators: name: Erler, Theodore
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The split string formalism offers a simple template upon which we can build many generalizations of Schnabl's analytic solution of open string field theory. In this paper we consider two such generalizations: one which replaces the wedge state by an arbitrary function of wedge states, and another which generalizes the solution to conformal frames other than the sliver.
description: 25 pages, 11 figures. Figures and discussion in Section 4 improved
Νέες πολιτικές εισαγωγής στην αγγλική τριτοβάθμια εκπαίδευση: λειτουργικός εκσυγχρονισμός ή συντηρητική ανασύνταξη;
Creators: name: Ματθαίου, Δημήτρης
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1996

description: Since 1979 a number of very important changes have taken place in the English education system. It has been argued that all of them constitute a messy set of compromises between neo-liberal and neo-conservative ideologies and policies. In the light of this thesis the present article examines the introduction of GNVQs and argues that their co-existence with GCE A levels may indicate a conservative rally rather than a modernization enterprise.
description: Παιδαγωγική Επιθεώρηση, Vol. 24 (1996)
Αριθμητική μελέτη της απορρόφησης ακτινοβολίας RF κατά την εξέταση σε μαγνητικό τομογράφο παρουσία ηλεκτροδίων ενεργών εμφυτευμάτων
Creators: name: Σαμαράς, Σταύρος Χρυσάφη
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Μαγνητική τομογραφία
Ρυθμός ειδικής απορρόφησης
Υπολογισμός ρυθμού ειδικής απορρόφησης ηλεκτροδίων ενεργών εμφυτευμάτων κατά την εξέταση σε μαγνητικό τομογράφο
Magnetic resonance imaging
Specific absorption rate
Specific absorption rate calculation of leads of active implants during MRI examination

description: Η μαγνητική τομογραφία αποτελεί μία από τις πιο έγκυρες και ασφαλείς διαγνωστικές μεθόδους με εφαρμογές σε πολλούς κλάδους της ιατρικής αλλά και σε άλλους τομείς όπως είναι η βιολογία και η γεωλογία. Στην παρούσα διπλωματική εργασία ασχοληθήκαμε με τον αριθμητικό υπολογισμό της απορρόφησης ακρινοβολίας RF κατά την εξέταση με μαγνητικό τομογράφο παρουσία ηλεκτροδίων ενεργών εμφυτευμάτων. Το υπολογιστικό περιβάλλον στο οποίο εργαστήκαμε ήταν το SEMCAD-X. Κατασκευάσαμε καλώδια του ίδιου υλικού αλλά με διαφορετικές γεωμετρίες και τα τοποθετήσαμε σε ένα ομοίωμα σώματος ASTM - F2182. Στη συνέχεια έπειτα από μια σειρά προσομοιώσεων υπολογίσαμε τον δείκτη SAR για να εξετάσουμε ποιος είναι ο καλύτερος τρόπος τοποθέτησης ηλεκτροδίου ενεργού εμφυτεύματος σε έναν ασθενή, έτσι ώστε κατά την εξέταση σε έναν μαγνητικό τομογράφο να υπάρχει η μικρότερη δυνατή απορρόφηση RF ακτινοβολίας. Η αριθμητική μέθοδος που χρησιμοποιήσαμε για την επίλυση των εξισώσεων του ηλεκτρικού και μαγνητικού πεδίου ήταν η FDTD. Για την καλύτερη διαχείρηση της μνήμης του υπολογιστή και του χρόνου της προσομοίωσης χρησιμοποιήσαμε την τεχνική της πηγής Huygens.
description: MRI is one of the most reliable and safe diagnostic methods with applications in many fields of medicine and in other sectors such as biology and geology. In this thesis we focused on the arithmetical calculation of the absorption of the RF radiation during the MRI test presence of leads of active implants. The computing environment in which we worked was SEMCAD-X. We constructed leads of the same material but with different geometries and we placed them in a body phantom ASTM - F2182. Then after a series of simulations we calculated SAR indicator to examine which is the best method to place a lead of an active implant in a patient, so during a MRI test to have the smallest possible absorption of RF radiation. The numerical method we used to solve the equations of electric and magnetic field was FDTD. For better management of computer memory and time of the simulation we used the technique of Huygens source.
Gaussian fluctuations of a nonlinear stochastic heat equation in dimension two
Creators: name: Tao, Ran
Publisher: name: arXiv
Year: 2022
Subjects: subject: Probability (math.PR)
subject: FOS: Mathematics

description: We study the Gaussian fluctuations of a nonlinear stochastic heat equation in spatial dimension two. The equation is driven by a Gaussian multiplicative noise. The noise is white in time, smoothed in space at scale $\varepsilon$, and tuned logarithmically by a factor $\frac{1}{\sqrt{\log \varepsilon^{-1}}}$ in its strength. We prove that, after centering and rescaling, the solution random field converges in distribution to an Edwards-Wilkinson limit as $\varepsilon \downarrow 0$. The tool we used here is the Malliavin-Stein's method. We also give a functional version of this result.