cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Post-Newtonian N-body simulations
Creators: name: Aarseth, Sverre J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We report on the first fully consistent conventional cluster simulation which includes terms up to post^{5/2} Newtonian in the potential of the massive body. Numerical problems for treating extremely energetic binaries orbiting a single massive object are circumvented by employing the special ``wheel-spoke'' regularization method of Zare (1974) which has not been used in large-N simulations before. Idealized models containing N = 10^5 particles of mass 1 M_sun with a central black hole of 300 M_sun have been studied on GRAPE-type computers. An initial half-mass radius of r_h = 0.1 pc is sufficiently small to yield examples of relativistic coalescence. This is achieved by significant binary shrinkage within a density cusp environment, followed by the generation of extremely high eccentricities which are induced by Kozai (1962) cycles and/or resonant relaxation. More realistic models with white dwarfs and ten times larger half-mass radii also show evidence of GR effects before disruption. Experimentation with the post-Newtonian terms suggests that reducing the time-scales for activating the different orders progressively may be justified for obtaining qualitatively correct solutions without aiming for precise predictions of the final gravitational radiation wave form. The results obtained suggest that the standard loss-cone arguments underestimate the swallowing rate in globular clusters containing a central black hole.
description: 8 pages, 6 figures, submitted to MNRAS
Systematic Oil Flow Modeling in the Quasi-3D Approximation Yields Additional Terms that Allows for Variable Cross-Section Area Tubing
Creators: name: Santos, Edval J. P.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Geophysics (physics.geo-ph)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: A systematic model development for oil flow in quasi-3D (1D + 2D) is presented. Our approach provides a unified modeling scheme. Besides, additional terms are obtained, which allows for tubing area variation along the flow direction. The area variation can be modeled as analytic function or random fluctuation, as it could be the result of deposits or tubing internal surface roughness. The proposed approach can be used to obtain analytic solutions which provide physical insight into the phenomena under scrutiny, including the validation of software tools, sensor development and sensor placement. One starts from conservation laws as given by kinetic theory and applies the transverse averaging technique (TAT) to extract the one-dimensional approximation in formal grounds. To demonstrate its application, the steady-state Ramey's model, the Hasan's transient model and a simple two-phase model are generated from the obtained equations.
description: 19 pages, 3 figures
Enhanced Two-Channel Kondo Physics in a Quantum Box Device
Creators: name: Kakashvili, Paata
name: Johannesson, Henrik
Publisher: name: arXiv
Year: 2006
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We propose a design for a one-dimensional quantum box device where the charge fluctuations are described by an anisotropic two-channel Kondo model. The device consists of a quantum box in the Coulomb blockade regime, weakly coupled to a quantum wire by a single-mode point contact. The electron correlations in the wire produce strong back scattering at the contact, significantly increasing the Kondo temperature as compared to the case of non-interacting electrons. By employing boundary conformal field theory techniques we show that the differential capacitance of the box exhibits manifest two-channel Kondo scaling with temperature and gate voltage, uncontaminated by the one-dimensional electron correlations. We discuss the prospect to experimentally access the Kondo regime with this type of device.
description: EPL style, 5 pages, 1 figure, final published version
Οι χρήσεις του Διονυσίου Αρεοπαγίτου στην ’’ Επιτομή είτε συλλογή των θείων της πίστεως δογμάτων’’ του Αγίου Αθανασίου Παρίου
Creators: name: Κωτάκη, Αικατερίνη Δημητρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Διονύσιος Αρεοπαγίτης
Αθανάσιος Πάριος
Θεία ονόματα
Dionysious Areopagitis
Athanasios Parios
Divine names

description: Στόχος της παρούσης μελέτης ήταν εφόσον αναγνωστούν λεπτομερώς τα κείμενα του Αγίου Διονυσίου Αρεοπαγίτου με τίτλο «Το Περί Θείων Ονομάτων» και του Αγίου Αθανασίου Παρίου με τίτλο «Επιτομή είτε συλλογή των Θείων της Πίστεως δογμάτων» να μπορέσει να γίνει μια συνοπτική αλλά λεπτομερής παρουσίαση των θεωνυμιών - θείων ονομάτων του Θεού. Συμπερασματικά καταλήξαμε πως ο Άγιος Αθανάσιος είναι υπέρ στο να χρησιμοποιούμε τον δοκιμασμένο τρόπο του θεολογείν, γιατί θεωρεί, πως χρησιμοποιώντας τους προγενέστερους Πατέρες, είναι η μόνη δυνατότητα για να θεολογήσει κανείς σωστά και αυτό κάνει. Και έπειτα καταλήξαμε πως κανένα όναμα δεν προσιδιάζει στον Τριαδικό Θεό, και ότι όλα είναι περιγραπτά και ενδεικτικά της «του παντοκράτορος δυνάμεως» και ας υμνήται ταυτόχρονα ως ανώνυμος και ως πολυώνυμος αλλά και με τα καθ’ υπεροχήν ονόματα. Τίποτα και κανείς δεν μπορεί να αποδώσει την ύπαρξη, ή την οντότητα του, γιατί ο Θεός δεν μοιάζει με τίποτε από αυτά που γνωρίζει ο άνθρωπος.
description: The aim of this study was if read thoroughly the writings of St. Dionysius Areopagite titled "On Divine Names" and St. Athanasius Parion entitled "Compendium, or collections of divine doctrines of the faith" to enable a concise yet thorough presentation of theonymion - divine names of God. We conclude that Saint Athanasius favor to use the tried and tested way of theologizing because believes that using the earlier Fathers, is the only way to correct theologizing and this one does. And then we think no onama not peculiar to the Triune God, and that everything is described and illustrate the "power of the Almighty" and let ymnitai simultaneously as anonymous as polynomial but also with itself superiority names. Nothing and no one can afford the existence or entity, because God does not like any of those known to man.
Security Analysis and Improvement of Source Independent Quantum Random Number Generators with Imperfect Devices
Creators: name: Lin, Xing
name: Wang, Shuang
name: Yin, Zhen-Qiang
name: Fan-Yuan, Guan-Jie
name: Wang, Rong
name: Chen, Wei
name: He, De-Yong
name: Zhou, Zheng
name: Guo, Guang-Can
name: Han, Zheng-Fu
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A quantum random number generator (QRNG) as a genuine source of randomness is essential in many applications, such as number simulation and cryptography. Recently, a source-independent quantum random number generator (SI-QRNG), which can generate secure random numbers with untrusted sources, has been realized. However, the measurement loopholes of the trusted but imperfect devices used in SI-QRNGs have not yet been fully explored, which will cause security problems, especially in high-speed systems. Here, we point out and evaluate the security loopholes of practical imperfect measurement devices in SI-QRNGs. We also provide corresponding countermeasures to prevent these information leakages by recalculating the conditional minimum entropy and adding a monitor. Furthermore, by taking into account the finite-size effect,we show that the influence of the afterpulse can exceed that of the finite-size effect with the large number of sampled rounds. Our protocol is simple and effective, and it promotes the security of SI-QRNG in practice as well as the compatibility with high-speed measurement devices, thus paving the way for constructing ultrafast and security-certified commercial SI-QRNG systems.
description: 15 pages, 6 figures
Ανάπτυξη και χρήση αισθητήρων για την ανίχνευση συναισθημάτων μαθητών και εφαρμογή τους σε προσαρμοστικό εκπαιδευτικό περιβάλλον:
Creators: name: Παρασκευά, Αννα Χρυσοστόμου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Βιοσήματα
Bιοανάδραση
Βιοαισθητήρες
Μέτρηση καρδιακών παλμών
GSR
BVP
Ανίχνευση συναισθημάτων
Biosignals
Biofeedback
Biosensors
Heart rate measurement
Emotion detection

description: Η παρούσα εργασία ασχολείται με την ανάπτυξη και την αξιολόγηση μιας πρωτότυπης συσκευής ικανής να συλλέγει και να αξιοποιεί βιο-σήματα. Οι τιμές των λαμβανόμενων βιο-σημάτων αφορούν τις φυσιολογικές αντιδράσεις του οργανισμού, οι οποίες επηρεάζουν την υγρασία του δέρματος και τον καρδιακό παλμό. Έτσι δίνεται η δυνατότητα να ερμηνευθούν κάποιες βασικές συναισθηματικές καταστάσεις ενός ατόμου. Πιο συγκεκριμένα καταστάσεις άγχους έχουν συχνά σαν αποτέλεσμα να αυξάνεται η υγρασία στο ανθρώπινο δέρμα και να προκαλείται σε πολλά άτομα ταχυπαλμία. Η ρύθμιση έντονων συναισθηματικών καταστάσεων μπορεί να είναι ένας σημαντικός παράγοντας στην εφαρμογή της προσαρμοστικότητας των μαθησιακών δραστηριοτήτων με στόχο την αποκατάσταση της ηρεμίας η οποία μπορεί να συμβάλλει αποφασιστικά στην καλύτερη απόδοση αυτών που συμμετέχουν στην δραστηριότητα.
description: The purpose of this paper is the development and the evaluation of a device that collects bio-signals by people engaged in learning activities and it assigns them to emotional states. The physiological reactions of the body, affects the conductivity of the skin and the heart rate producing bio-signals that provides the opportunity to estimate some basic human emotional states. In particular stressful situations are usually resulting in increased human skin moisture, reducing the resistance and increasing the skin conductivity to electrical current. Also people under stressful conditions usually show increased heart rate values. This work suggests that emotional state recognition and regulation may be an important factor in implementing the adaptivity of learning activities.
Disposing of the dead : a shell midden cemetery in British Columbia’s Gulf of Georgia region
Creators: name: Brown, Douglas Ronald
Publisher: name: University of British Columbia
Year: 2009

description: Archaeological excavations undertaken at the Somenos Creek site (DeRw 18) in 1994 were designed to evaluate the model of the site as an exclusive burial enclave for social elites during the last half of the Marpole culture phase (2400-1000 B.P.). The site first came to the attention of archaeologists in 1992, when land modification activities on the north bank of Somenos Creek resulted in the accidental disturbance of human burials. Burial data from a subsequent archaeological salvage operation raised the possibility that all the individuals interred at this southeastern Vancouver Island site may have been social elites. The fact that these apparently high-status burials were found in an inland shell deposit suggested that crushed shell may have been imported and placed in order to designate symbolically an exclusive burial location. Evaluating the burial enclave model involved a stratigraphic analysis of the shell deposit, an analysis of the cultural and temporal relationship of the shell deposit to the human burials, and a comparison of the Somenos Creek burial pattern with that of the nearby False Narrows site (DgRw 4). Expectations stemming from the model were that the shell deposit would not exhibit stratigraphic evidence for in situ development of a shell refuse midden. Further, had shell been imported to the site from an existing midden, one would expect the shell material to be older than the associated burials. Finally, all the Somenos Creek burials would be expected to correspond to the high-status burials found at False Narrows. Results show the Somenos Creek shell deposit to be a shell midden, in all likelihood the accumulated refuse from a small settlement. The Somenos Creek burial pattern appears to reflect at least two social strata. Significantly, all the Somenos Creek burials post-date the shell midden, indicating a shift in site use from settlement to cemetery. These results contradict the long-held view among archaeologists that Marpole societies interred their dead in shell middens behind occupied villages. In addition, researchers conducting cross-cultural analyses of ethnographic societies have found that when cemeteries occur, they tend to represent corporate groups which control crucial resources. These corporate groups are likely to legitimize rights of membership, resource control and inheritance by invoking claims of lineal descent from the dead.
Non-Hermitian Topology of Microcavity Exciton Polaritons
Creators: name: Hu, Yow-Ming Robin
Publisher: name: The Australian National University
Year: 2021
Subjects: non-Hermitian physics
topology
exciton polaritons
photonics
condensed matter

description: Topology in solid state physics gave a new way to classify materials using quantities called topological invariants. Phases with non-vanishing topological invariants can exhibit non-trivial dynamics of charge-carriers at the boundary which is protected against scattering with impurities and imperfections. The study of topology has recently been generalized to a new class of systems with dissipation, which can be described by effective non-Hermitian Hamiltonians and have complex-valued eigenenergies. It has been discovered that there are topological invariants unique to non-Hermitian systems. One of them—spectral winding arises near the exceptional points (the non-Hermitian spectral degeneracies). In this thesis, I investigated the non-Hermitian topology of a mixed light-matter system—microcavity exciton polaritons. The exciton polaritons are composite particles created by strongly coupling bound electron-hole pairs (excitons) to photons in a microcavity. They can be described by a non-Hermitian Hamiltonian because both gain (via optical pumping) and loss (radiative decay) are always present in the system. The ANU Polariton BEC group has previously observed a non-Hermitian spectral degeneracy in this system and, in a separate study, detected the spectral winding around a pair of the exceptional points. However, a comprehensive theory of non-Hermitian topology for this system has not yet been developed. In this thesis, I took the first essential steps towards building a theoretical framework for studies of non-Hermitian topology in exciton-polariton systems. In particular, I derived quantities that characterise the global properties of the eigenvalues that are analogous to those used in Hermitian topological systems. One important topological invariant in the solid state system is the Chern number. The Chern number is realted to a quantity called the Berry curvature, which acts on the electrons in the solid state system as an effective magnetic field when an external field is absent. The Berry curvature is part of a larger quantity called the quantum geometric tensor. The real part of quantum geometric tensor is a metric that defines the distance between two states in momentum space, while its imaginary part is related to the Berry curvature. In this thesis, I generalized the quantum geometric tensor to non- Hermitian systems using a recently developed formalism (Chapter 4). I then investigated the properties of the components of the four quantum geometric tensors and concluded that two of them are the natural non-Hermitian generalizations, while the remaining ones are inconsistent (Chapter 5). This conclusion was further supported by investigation of exciton-polariton wavepacket dynamics (Chapter 6). The last Chapter of this thesis summarises conclusions drawn from my study and presents an outlook on further research.
Self-induced decoherence in dense neutrino gases
Creators: name: Raffelt, G. G.
name: Sigl, G.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Dense neutrino gases exhibit collective oscillations where "self-maintained coherence" is a characteristic feature, i.e., neutrinos of different energies oscillate with the same frequency. In a non-isotropic gas, however, the flux term of the neutrino-neutrino interaction has the opposite effect of causing kinematical decoherence of neutrinos propagating in different directions, an effect that is at the origin of the "multi-angle behavior" of neutrinos streaming off a supernova core. We cast the equations of motion in a form where the role of the flux term is manifest. We study in detail the symmetric case of equal neutrino and antineutrino densities where the evolution consists of collective pair conversions ("bipolar oscillations"). A gas of this sort is unstable in that an infinitesimal anisotropy is enough to trigger a run-away towards flavor equipartition. The "self-maintained coherence" of a perfectly isotropic gas gives way to "self-induced decoherence."
description: Revtex, 16 pages, 12 figures
A complete structure of the three-layer Zamolodchikov model
Creators: name: Jinliang, Ren
Publisher: name: The Australian National University
Year: 2021
Subjects: Integrable system
Exactly Solvable model
Zamolodchikov model
sl(n)-chiral Potts model

description: The aim of this thesis is to investigate the Zamolodchikov model by using the equivalence to the sl(n)-chiral Potts model. The Zamolodchikov model is a three-dimensional exactly solvable model. It was constructed by Baxter[4] according to the solution of the tetrahedron equation obtained by Zamolodchikov[31]. In particular, we considered the minimum non-trivial case, the three-layer model Zamolodchikov model. Using the equivalency, we constructed the general Boltzmann weights and transfer matrices of the sl(3)-chiral Potts model. We also analysed the commutation relations by using the “starstar” relation[6] and found that the relations are shifted by one spin along the chain in the horizontal direction. The functional relations of the eigenvalues of transfer matrices were constructed by generalizing the results from paper [11] and [10]. It was noticed that the shifted relations forbid us from using the methods of studying the homogeneous Zamolodchikov model. The Bethe ansatz equations were derived for general three-layer Zamolodchikov model and simplified for some particular cases.
GLACE survey: galaxy activity in ZwCl0024+1652 cluster from strong optical emission lines
Creators: name: Beyoro-Amado, Zeleke
name: Sánchez-Portal, Miguel
name: Bongiovanni, Angel
name: Pović, Mirjana
name: Tessema, Solomon B.
name: Pérez-Martínez, Ricardo
name: García, Ana María Pérez
name: Cerviño, Miguel
name: Nadolny, Jakub
name: Cepa, Jordi
name: González-Serrano, J. Ignacio
name: Pintos-Castro, Irene
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Although ZwCl0024+1652 galaxy cluster at $z\sim0.4$ has been thoroughly analysed, it lacks a comprehensive study of star formation and nuclear activity of its members. With GaLAxy Cluster Evolution (GLACE) survey, a total of 174 H$α$ emission-line galaxies (ELGs) were detected, most of them having [NII}]. We reduced and analysed a set of [OIII] and H$β$ tunable filter (TF) observations within GLACE survey. Using H$α$ priors, we identified [OIII] and H$β$ in 35 ($\sim$20%) and 59 ($\sim$34%) sources, respectively, with 21 of them having both emission lines, and 20 having in addition [NII]. Applying BPT-NII diagnostic diagram, we classified these ELGs into 40% star-forming (SF), 55% composites, and 5% LINERs. Star formation rate (SFR) measured through extinction corrected H$α$ fluxes increases with stellar mass ($\mathrm{M}_{*}$), attaining its peak at $\mathrm{M}_{*}\sim10^{9.8}\mathrm{M}_\odot$. We observed that the cluster centre to $\sim$1.3Mpc is devoid of SF galaxies and AGN. Our results suggest that the star formation efficiency declines as the local density increases in the cluster medium. Moreover, the SF and AGN fractions drop sharply towards high-density environments. We observed a strong decline in SF fraction in high $\mathrm{M}_*$, confirming that star formation is highly suppressed in high-mass cluster galaxies. Finally, we determined that SFR correlates with $\mathrm{M}_*$ while specific SFR (sSFR) anti-correlates with $\mathrm{M}_*$, both for cluster and field. This work shows the importance and strength of TF observations when studying ELGs in clusters at higher redshifts. We provide with this paper a catalogue of ELGs with H$β$ and/or [OIII] lines in ZwCl0024+1652 cluster.
description: Accepted for publication in MNRAS main journal, 22 pages, 21 figures
Experimental proof of moisture clog through neutron tomography in a porous medium under truly one-directional drying
Creators: name: Moreiraa, M. H.
name: Pont, S. Dal
name: Tengattinib, A.
name: Luz, A. P.
name: Pandolfelli, V. C.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Structural failure of concrete buildings on fire and complete destruction of the monolithic refractory lining during their drying stage are dangerous examples of the effect of explosive spalling on partially saturated porous media. Several observations in both cases indicated the presence of moisture accumulation ahead of the drying front, which are in tune with the most common theories on the explosive spalling of concrete. Previous studies have shown evidence of the existence of this phenomenon, however, they were biased by artifacts and experimental limitations (such as the beam hardening effect and changes in the microstructure of the material due to the presence of pressure and temperature sensors). In the current work, rapid neutron tomography was used to investigate the in-operando drying behavior of a high-alumina refractory castable, proposing a novel experimental layout aimed at a truly one-dimensional drying front. This setup provided more realistic boundary conditions, such as the behavior of a larger wall heated from one of its sides, while also preventing some nonphysical artifacts (notably beam hardening). By eliminating these aspects, a direct proof that moisture accumulates ahead of the drying front was obtained. This work also lays the basis for further studies focusing on the response sensitivity analysis to boundary conditions and other parameters (e.g., heating rates and properties of the sample related to the moisture clog formation), as well as useful data for the validation and characterization stages of numerical models of partially saturated porous media.
Tunable valley splitting and bipolar operation in graphene quantum dots
Creators: name: Tong, Chuyao
name: Garreis, Rebekka
name: Knothe, Angelika
name: Eich, Marius
name: Sacchi, Agnese
name: Watanabe, Kenji
name: Taniguchi, Takashi
name: Fal'ko, Vladimir
name: Ihn, Thomas
name: Ensslin, Klaus
name: Kurzmann, Annika
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Quantum states in graphene are four-fold degenerate: two fold in spins, and two fold in valleys.Both degrees of freedom can be utilized for qubit preparations. In our bilayer graphene quantumdots, we demonstrate that the valley g-factorgv, defined analogously as the spin g-factorgsforvalley splitting in perpendicular magnetic field, is tunable by over a factor of 4 from 20 to 90. Wefind that largergvresults from larger electronic dot sizes, determined from the charging energy.This control is achieved by adjusting voltages on merely two gates, which also allows for tuning ofthe dot-lead tunnel coupling. On our versatile device, bipolar operation, charging our quantum dotwith charge carriers of the same or the opposite polarity as the leads, can be performed. Dots ofboth polarity are tunable to the first charge carrier by action of the plunger gate, such that thetransition from an electron to a hole dot can be observed. By adding more gates, this system caneasily be extended to host double dots.
description: 10 pages, 7 figures
Neural News Recommendation with Negative Feedback
Creators: name: Wu, Chuhan
name: Wu, Fangzhao
name: Huang, Yongfeng
name: Xie, Xing
Publisher: name: arXiv
Year: 2021
Subjects: subject: Information Retrieval (cs.IR)
subject: FOS: Computer and information sciences

description: News recommendation is important for online news services. Precise user interest modeling is critical for personalized news recommendation. Existing news recommendation methods usually rely on the implicit feedback of users like news clicks to model user interest. However, news click may not necessarily reflect user interests because users may click a news due to the attraction of its title but feel disappointed at its content. The dwell time of news reading is an important clue for user interest modeling, since short reading dwell time usually indicates low and even negative interest. Thus, incorporating the negative feedback inferred from the dwell time of news reading can improve the quality of user modeling. In this paper, we propose a neural news recommendation approach which can incorporate the implicit negative user feedback. We propose to distinguish positive and negative news clicks according to their reading dwell time, and respectively learn user representations from positive and negative news clicks via a combination of Transformer and additive attention network. In addition, we propose to compute a positive click score and a negative click score based on the relevance between candidate news representations and the user representations learned from the positive and negative news clicks. The final click score is a combination of positive and negative click scores. Besides, we propose an interactive news modeling method to consider the relatedness between title and body in news modeling. Extensive experiments on real-world dataset validate that our approach can achieve more accurate user interest modeling for news recommendation.
Μελέτη του φαινομένου του παγετού στην ελληνική περιοχή: μελλοντικές εκτιμήσεις με τη χρήση των δυναμικών περιοχικών μοντέλων του Ensembles
Creators: name: Βελίκου, Κονδυλία Κωνσταντίνου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Μερικός-Ολικός Παγετός
Περίοδος Ελεύθερης Παγετού
Δυναμικά Μοντέλα
Ελλάδα
Frost Days
Frost-Free Period
Dynamical Models
Greece

description: Σύμφωνα με την τελευταία έκθεση του IPCC (IPCC 2007) ήδη τα τελευταία χρόνια σε παγκόσμια κλίμακα παρατηρείται μια έντονη μείωση των ημερών παγετού κυρίως σε περιοχές των μέσων γεωγραφικών πλατών. Αντίστοιχα και οι μελλοντικές προβολές των περιοχικών μοντέλων συμφωνούν ότι τόσο στην Ευρώπη όσο και στην περιοχή της Μεσογείου αναμένεται περαιτέρω μελλοντική μείωση των ημερών παγετού ως το τέλος του 21ου αιώνα. Στην παρούσα μελέτη κύριο στόχο αποτελεί η στατιστική ανάλυση των χαρακτηριστικών του παγετού στην ελληνική περιοχή. Θα χρησιμοποιηθούν δεδομένα μέγιστης και ελάχιστης θερμοκρασίας για 22 σταθμούς ομοιόμορφά κατανεμημένους στον ελλαδικό χώρο και θα μελετηθούν οι μέρες μερικού και ολικού παγετού, καθώς και η περίοδος ελεύθερης παγετού για τους επιλεγμένους σταθμούς. Στη συνέχεια με τη χρήση προσομοιώσεων σύγχρονων δυναμικών μοντέλων, που δημιουργήθηκαν στα πλαίσια του ερευνητικού ευρωπαϊκού προγράμματος ENSEMBLES, θα γίνει μια πρώτη εκτίμηση των μελλοντικών αλλαγών των παραμέτρων αυτών που χαρακτηρίζουν τον παγετό λόγω της έντασης του φαινομένου του θερμοκηπίου.
description: According to the latest IPCC report (IPCC 2007) during the last decades an extensive reduction in the number of frost days has been observed mainly in the mid-latitude regions. Furthermore, the dynamical projections from several models estimate an additional decrease of the frost days all over Europe and especially in the Mediterranean region until the end of the 21st century. Thus, the main score of the present study is the statistical analysis of the frost characteristics in the Greek region. Maximum and minimum temperature daily data will be utilized for 22 meteorological stations uniformly distributed over the domain of study and the analysis of the number of frost days and the length of the frost-free period will take place. Finally, using the future projections of updated regional climate models, developed under the frame of the ENSEMBLES project, we will estimate the future changes of the aforementioned parameters due to the enhancement of the greenhouse effect.
Improving future gravitational-wave detectors using nondegenerate internal squeezing
Creators: name: Gardner, James Walter
Publisher: name: The Australian National University
Year: 2021
Subjects: Gravitational waves
gravitational-wave detection
gravitational-wave detectors
kilohertz
sensitivity
kilohertz sensitivity
quantum noise
squeezing
quantum squeezing
internal squeezing
quantum optics
nondegenerate squeezing
nondegenerate internal squeezing
idler readout

description: Gravitational waves are "ripples" in spacetime emitted by massive astrophysical events. Over the past decade, interferometric detectors have been used to measure gravitational waves from the binary mergers of black holes and neutron stars to learn more about such systems; these gravitational waves had frequencies around 100 Hz. Other frequencies of gravitational waves are thought to exist and contain valuable information but are yet to be detected. For example, detecting kilohertz (1–4 kHz) gravitational waves from binary neutron-star mergers could be used to further constrain the neutron-star equation-of-state and better understand exotic states of matter. However, to do so, the sensitivity of current detectors will need to be extended from 100 Hz to the kilohertz regime. The kilohertz sensitivity of current gravitational-wave detectors is limited by quantum noise from the fundamental quantum uncertainties in the state of light inside the detector. This noise can be mitigated by replacing the vacuum fluctuations entering the readout port of the detector with squeezed states. In this thesis, I investigate a new technique to improve kilohertz sensitivity by placing a nondegenerate squeezer inside the detector. This technique, called nondegenerate internal squeezing, improves sensitivity by amplifying the detector's response to the gravitational-wave signal more than it increases the quantum noise. To assess its feasibility, I derive an analytic Hamiltonian model of nondegenerate internal squeezing and calculate its sensitivity and stability as well as analyse its tolerance to the realistic optical losses expected in a future gravitational-wave detector. My model indicates that nondegenerate internal squeezing is stable, robust to detection loss in the readout, and provides a viable alternative to other proposals to improve kilohertz sensitivity. I demonstrate a technique to determine its squeezing threshold and, therefore, the limits of its operation. I find that nondegenerate internal squeezing could feasibly improve the sensitivity of a future detector to 1–4 kHz gravitational waves. I also explore an alternative readout scheme that is promising for broadband 0.1–4 kHz sensitivity.
Multiple Hypothesis Semantic Mapping for Robust Data Association
Creators: name: Bernreiter, Lukas
name: Gawel, Abel
name: Sommer, Hannes
name: Nieto, Juan
name: Siegwart, Roland
name: Cadena, Cesar
Publisher: name: arXiv
Year: 2020
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: In this paper, we present a semantic mapping approach with multiple hypothesis tracking for data association. As semantic information has the potential to overcome ambiguity in measurements and place recognition, it forms an eminent modality for autonomous systems. This is particularly evident in urban scenarios with several similar looking surroundings. Nevertheless, it requires the handling of a non-Gaussian and discrete random variable coming from object detectors. Previous methods facilitate semantic information for global localization and data association to reduce the instance ambiguity between the landmarks. However, many of these approaches do not deal with the creation of complete globally consistent representations of the environment and typically do not scale well. We utilize multiple hypothesis trees to derive a probabilistic data association for semantic measurements by means of position, instance and class to create a semantic representation. We propose an optimized mapping method and make use of a pose graph to derive a novel semantic SLAM solution. Furthermore, we show that semantic covisibility graphs allow for a precise place recognition in urban environments. We verify our approach using real-world outdoor dataset and demonstrate an average drift reduction of 33 % w.r.t. the raw odometry source. Moreover, our approach produces 55 % less hypotheses on average than a regular multiple hypotheses approach.
In-plane uniaxial pressure-induced out-of-plane antiferromagnetic moment and critical fluctuations in BaFe$_2$As$_2$
Creators: name: Liu, Panpan
name: Klemm, Mason L.
name: Tian, Long
name: Lu, Xingye
name: Song, Yu
name: Tam, David W.
name: Schmalzl, Karin
name: Park, J. T.
name: Li, Yu
name: Tan, Guotai
name: Su, Yixi
name: Bourdarot, Frederic
name: Zhao, Yang
name: Lynn, Jeffery W.
name: Birgeneau, Robert J.
name: Dai, Pengcheng
Publisher: name: arXiv
Year: 2020
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: A small in-plane external uniaxial pressure has been widely used as an effective method to acquire single domain iron pnictide BaFe$_2$As$_2$, which exhibits twin-domains without uniaxial strain below the tetragonal-to-orthorhombic structural (nematic) transition temperature $T_s$. Although it is generally assumed that such a pressure will not affect the intrinsic electronic/magnetic properties of the system, it is known to enhance the antiferromagnetic (AF) ordering temperature $T_N$ ($
description: 11 pages, 4 figures, Supplementary information is available upon request
On Irrelevant Literals in Pseudo-Boolean Constraint Learning
Creators: name: Berre, Danel Le
name: Marquis, Pierre
name: Mengel, Stefan
name: Wallon, Romain
Publisher: name: arXiv
Year: 2020
Subjects: subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: Learning pseudo-Boolean (PB) constraints in PB solvers exploiting cutting planes based inference is not as well understood as clause learning in conflict-driven clause learning solvers. In this paper, we show that PB constraints derived using cutting planes may contain \emph{irrelevant literals}, i.e., literals whose assigned values (whatever they are) never change the truth value of the constraint. Such literals may lead to infer constraints that are weaker than they should be, impacting the size of the proof built by the solver, and thus also affecting its performance. This suggests that current implementations of PB solvers based on cutting planes should be reconsidered to prevent the generation of irrelevant literals. Indeed, detecting and removing irrelevant literals is too expensive in practice to be considered as an option (the associated problem is NP-hard.
description: published at IJCAI 2020
Das ägyptische Exilparlament: Struktur, Ziele, Legitimität (Stand: April 2015)
Creators: name: Lübben, Ivesa
Publisher: name: Philipps-Universität Marburg
Year: 2015
Subjects: subject: Opposition
subject: Political science
subject: FOS: Political science
subject: Muslimbruderschaft
subject: Exil
subject: Türkei
subject: Islamismus

description: Am 20.Dezember 2014 konstituierte sich in Istanbul ein ägyptisches Exilparlament. Ihm gehören Mitglieder des Ende 2011 gewählten Parlaments (Volksrat/arab.: majlis al-shaab) und dem 2012  gewählten Senat (Konsultativrat/arabisch: majlis al-shura) an. Das Parlament wurde nur sechs Monate nach seiner Wahl im Juni 2012 durch einen Beschluss des Obersten Verfassungsgerichtes (Supreme Constitutional Council/SCC) für verfassungswidrig erklärt. Der Senat wurde 2013 nach der Machtergreifung des Supreme Council of Armed Forces (SCAF) von dem von den Militärs  bestellten Übergangspräsidenten Adly Mansour aufgelöst.  Das Exilparlament erkennt diese Maßnahmen nicht an. Es spricht dem amtierenden ägyptischem Präsidenten Abdel Fattah al-Sissi und der von ihm eingesetzten Regierung die Legitimität ab, da sein Regime durch einen Militärputsch gegen die legitimen Staatsorgane an die Macht gekommen sei. Das Exilparlament stellt sich in die Kontinuität der Revolution vom 25. Januar 2011 und fühlt sich deren Zielen – Freiheit, Menschenwürde und soziale Gerechtigkeit – verpflichtet. Es sieht in den Wahlen von 2011 und 2012 und der Erarbeitung der Verfassung von 2012 erste Schritte eines demokratischen Neuanfangs.
Die Strategie der Nour-Partei nach dem Militärputsch : Ziele, Vorgehen und Beweggründe (Stand: Juni 2014)
Creators: name: Reichinnek, Heidi
name: Lübben, Ivesa
Publisher: name: Philipps-Universität Marburg
Year: 2015
Subjects: subject: Islamismus
subject: Ägypten
subject: Salafija
subject: Political science
subject: FOS: Political science

description: Die Politisierung der salafistischen Szene Ägyptens nach den Umbrüchen 2011 kam für viele Beobachter überraschend. Noch überraschender war, dass die Hizb an-Nour (Partei des Lichts), die Partei der in Alexandria ansässigen Da’wa Salafiyya (salafistische Einladung zum Islam), aus den ersten freien Parlamentswahlen im gleichen Jahr mit 27,8 % als zweitstärkste Kraft hinter der  Freedom and Justice Party der Muslimbruderschaft hervorging. Beide Parteien wurden von da an in der externen Wahrnehmung zu einem monolithischen Block. Die Differenzen zwischen der Muslimbruderschaft und der Nour sowie die heterogenität der salafistischen Szene wurden jedoch kaum registriert.
Explosive synchronization in interlayer phase-shifted Kuramoto oscillators on multiplex networks
Creators: name: Kumar, Anil
name: Jalan, Sarika
Publisher: name: arXiv
Year: 2021
Subjects: subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: We show that an introduction of a phase parameter ($α$), with $0 \le α\le π/2$, in the interlayer coupling terms of multiplex networks of Kuramoto oscillators can induce explosive synchronization (ES) in the multiplexed layers. Along with the α values, the hysteresis width is determined by the interlayer coupling strength and the frequency mismatch between the mirror (inter-connected) nodes. A mean-field analysis is performed to support the numerical results. Similar to the earlier works, we find that the suppression of synchronization is accountable for the origin of ES. The robustness of ES against changes in the network topology and frequency distribution is tested. Finally, taking a suggestion from the synchronized state of the multiplex networks, we extend the results to the classical concept of the single-layer networks in which some specific links are assigned a phase-shifted coupling. Different methods have been introduced in the past years to incite ES in coupled oscillators; our results indicate that a phase-shifted coupling can also be one such method to achieve ES.
description: 9 pages, 8 figures
Prediction of tissue decompression in orbital surgery
Creators: name: Luboz, Vincent
name: Pedrono, Annaig
name: Ambard, Dominique
name: Boutault, Franck
name: Payan, Yohan
name: Swider, Pascal
Publisher: name: arXiv
Year: 2006
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: Objective: A method to predict the relationships between decompressed volume of orbital soft tissues, backward displacement of globe after osteotomy, and force exerted by the surgeon, was proposed to improve surgery planning in exophthalmia reduction. Design: A geometric model and a poroelastic finite element model were developed, based on Computed Tomography scan data. Background: The exophthalmia is characterised by a protrusion of the eyeball. Surgery consists in an osteotomy of the orbit walls to decompress the orbital content. A few clinical observations ruling on an almost linear relationship between globe backward displacement and tissue decompressed volume are described in the literature. Methods: Fast prediction of decompressed volume is derived from the geometric model: a sphere in interaction with a cone. Besides, a poroelastic Finite Element model involving morphology, material properties of orbital components and surgical gesture was implemented. Results: The geometric model provided a better decompression volume estimation than the Finite Element model. Besides, the Finite Element model permitted to quantify the backward displacement, the surgical gesture and the stiffness of the orbital content. Conclusions: The preliminary results obtained for one patient, in accordance with the clinical literature, were relatively satisfying. An efficient aid for location and size of osteotomies was derived and seemed to be able to help in the surgery planning. Relevance: To our knowledge, this paper concerns the first biomechanical study of exophthalmia reduction. The approach permitted to improve the treatment of orbitopathy and can be used in a clinical setting.
Γυναίκες εκπαιδευτικοί στη Δευτεροβάθμια Εκπαίδευση μιλούν για την επαγγελματική και προσωπική τους ζωή
Creators: name: Ζίχναλη, Σουλτάνα Δημητρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2012
Subjects: Αυτοβιογραφία
Επαγγελματική ανάπτυξη
Γυναίκες εκπαιδευτικοί
Autobiography
Teacher development
Women educators

description: Σκοπός της παρούσας εργασίας ήταν να μελετήσει την επαγγελματική ανάπτυξη τριών γυναικών εκπαιδευτικών της Δευτεροβάθμιας Εκπαίδευσης και το πώς αυτή συνδέθηκε με την προσωπική ζωή της καθεμίας. Η εργασία αποτελείται από δυο μέρη. Αρχικά, στο θεωρητικό μέρος της εργασίας επιχειρείται μια εννοιολογική προσέγγιση των όρων «επαγγελματική ανάπτυξη» και «επαγγελματίας εκπαιδευτικός». Στη συνέχεια παρουσιάζεται η ιστορική εξέλιξη του εκπαιδευτικού επαγγέλματος στην Ελλάδα και ειδικότερα των γυναικών εκπαιδευτικών. Το θεωρητικό μέρος ολοκληρώνεται με το κεφάλαιο για την αλληλεπίδραση φύλου και επαγγελματικής ανάπτυξης. Στο δεύτερο μέρος της εργασίας με τη βοήθεια της αυτοβιογραφικής μεθόδου διερευνάται το πώς οι γυναίκες της έρευνάς μας επέλεξαν το επάγγελμα της εκπαιδευτικού, πώς αντιλαμβάνονται τον επαγγελματικό τους ρόλο, την επαγγελματική πορεία που ακολούθησαν και τέλος, τα όποια εμπόδια συνάντησαν κατά τη διάρκεια της επαγγελματικής τους πορείας. Συνοπτικά, λοιπόν, η εργασία εξετάζει το πώς η αφήγηση νοηματοδοτεί το παρελθόν μέσα από το φίλτρο του παρόντος και την εμπειρία ζωής των υποκειμένων της έρευνας, ενώ παράλληλα σημειώνει και τη σημασία της εκπαίδευσης στη δόμηση της γυναικείας ταυτότητας.
description: The aim of the present thesis was to study the professional development of three women teachers in secondary education and how this was linked with their personal life. The study consists of two parts. At first, at the theoretical part of the study we attempt a conceptual approach of the terms "professional development" and "professional teacher". Then we present the historical development of the educational profession in Greece and especially of women’s education. Eventually, the theoretical part is completed with the chapter about the interaction between gender and professional development. In the second part with the help of the autobiographical method we examine how these three women chose the profession of teaching, how they perceive their professional role, the career path they followed and finally any obstacles encountered during their professional path. In summary, the paper examines how the narrative gives meaning to the past through the filter of the present and the life experiences of subjects, while notes the importance of education in the construction of female identity.
Evolution of perturbations of squashed Kaluza-Klein black holes: escape from instability
Creators: name: Ishihara, Hideki
name: Kimura, Masashi
name: Konoplya, Roman A.
name: Murata, Keiju
name: Soda, Jiro
name: Zhidenko, Alexander
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The squashed Kaluza-Klien (KK) black holes differ from the Schwarzschild black holes with asymptotic flatness or the black strings even at energies for which the KK modes are not excited yet, so that squashed KK black holes open a window in higher dimensions. Another important feature is that the squashed KK black holes are apparently stable and, thereby, let us avoid the Gregory-Laflamme instability. In the present paper, the evolution of scalar and gravitational perturbations in time and frequency domains is considered for these squashed KK black holes. The scalar field perturbations are analyzed for general rotating squashed KK black holes. Gravitational perturbations for the so called zero mode are shown to be decayed for non-rotating black holes, in concordance with the stability of the squashed KK black holes. The correlation of quasinormal frequencies with the size of extra dimension is discussed.
description: 12 pages, 6 figures
Prospects of measuring the branching fraction of the Higgs boson decaying into muon pairs at the International Linear Collider
Creators: name: Kawada, Shin-ichi
name: List, Jenny
name: Berggren, Mikael
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: The prospects for measuring the branching fraction of $H \to μ^+ μ^-$ at the International Linear Collider (ILC) have been evaluated based on a full detector simulation of the International Large Detector (ILD) concept, considering centre-of-mass energies ($\sqrt{s}$) of 250 GeV and 500 GeV. For both $\sqrt{s}$ cases, the two final states $e^+ e^- \to q\overline{q}H$ and $e^+ e^- \to ν\overlineνH$ have been analyzed. For integrated luminosities of 2 ab$^{-1}$ at $\sqrt{s} = 250$ GeV and 4 ab$^{-1}$ at $\sqrt{s} = 500$ GeV, the combined precision on the branching fraction of $H \to μ^+ μ^-$ is estimated to be 17{\%}. The impact of the transverse momentum resolution for this analysis is also studied.
description: 21 pages, 10 figures, 11 tables. This work was carried out in the framework of the ILD concept group
Thermal-nonthermal energy partition in solar flares derived from X-ray, EUV, and bolometric observations
Creators: name: Warmuth, Alexander
name: Mann, Gottfried
Publisher: name: arXiv
Year: 2020
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: In solar flares, energy is released impulsively and is partly converted into thermal energy of hot plasmas and kinetic energy of accelerated nonthermal particles. Despite numerous efforts, no consensus on quantifying this energy balance has yet been reached. We aim to understand the reasons for the contradicting results on energy partition obtained by various recent studies. We considered five recent studies that address the thermal-nonthermal energy partition in solar flares. Their results are reviewed, and their methods are compared and discussed in detail. The main uncertainties in deriving the energy partition are identified as (a) the derivation of the differential emission measure (DEM) distribution and (b) the role of the conductive energy loss for the thermal component, as well as (c) the determination of the low-energy cutoff for the injected electrons. The bolometric radiated energy, as a proxy for the total energy released in the flare, is a useful independent constraint on both thermal and nonthermal energetics. In most of the cases, the derived energetics are consistent with this constraint. There are indications that the thermal-nonthermal energy partition changes with flare strength: in weak flares, there appears to be a deficit of energetic electrons, while the injected nonthermal energy is sufficient to account for the thermal component in strong flares. This behavior is identified as the main cause of the dissimilar results in the studies we considered. The changing partition has two important consequences: (a) an additional direct (i.e. non-beam) heating mechanism has to be present, and (b) considering that the bolometric emission originates mainly from deeper atmospheric layers, conduction or waves are required as additional energy transport mechanisms.