cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Effect of data gaps on the detectability and parameter estimation of massive black hole binaries with LISA
Creators: name: Dey, Kallol
name: Karnesis, Nikolaos
name: Toubiana, Alexandre
name: Barausse, Enrico
name: Korsakova, Natalia
name: Baghi, Quentin
name: Basak, Soumen
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Massive black hole binaries are expected to provide the strongest gravitational wave signals for the Laser Interferometer Space Antenna (LISA), a space mission targeting $\sim\,$mHz frequencies. As a result of the technological challenges inherent in the mission's design, implementation and long duration (4 yr nominal), the LISA data stream is expected to be affected by relatively long gaps where no data is collected (either because of hardware failures, or because of scheduled maintenance operations, such as re-pointing of the antennas toward the Earth). Depending on their mass, massive black hole binary signals may range from quasi-transient to very long lived, and it is unclear how data gaps will impact detection and parameter estimation of these sources. Here, we will explore this question by using state-of-the-art astrophysical models for the population of massive black hole binaries. We will investigate the potential detectability of MBHB signals by observing the effect of gaps on their signal-to-noise ratios. We will also assess the effect of the gaps on parameter estimation for these sources, using the Fisher Information Matrix formalism as well as full Bayesian analyses. Overall, we find that the effect of data gaps due to regular maintenance of the spacecraft is negligible, except for systems that coalesce within such a gap. The effect of unscheduled gaps, however, will probably be more significant than that of scheduled ones.
description: 25 pages, 14 figures. Matches version published in Physical Review D
Η συνεργασία ανάμεσα στα στελέχη εκπαίδευσης: θεωρητική ανάλυση και εμπειρική διερεύνηση
Creators: name: Ναθαναήλ, Πασχαλία Χρ.
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Συνεργασία
Σχολικός σύμβουλος
Διευθυντής εκπαίδευσης
Στελέχη εκπαίδευσης
Διοίκηση εκπαίδευσης
Παιδαγωγική καθοδήγηση
Cooperation
School advisor
Director of education
Educational executives
Management in education
Pedagogical guidance

description: Το θέμα που πραγματεύεται η παρούσα θεωρητική και εμπειρική μελέτη είναι η συνεργασία των στελεχών εκπαίδευσης και ειδικότερα των σχολικών συμβούλων και των διευθυντών εκπαίδευσης των δύο σχολικών βαθμίδων. Βασικός σκοπός της εργασίας ήταν να διερευνηθεί σε ποιον βαθμό υφίσταται η συνεργασία ανάμεσα στους διευθυντές εκπαίδευσης και τους σχολικούς συμβούλους και αν και κατά πόσο συμβάλλει στην ποιοτική αναβάθμιση της εκπαίδευσης. Στο πλαίσιο της εμπειρικής διερεύνησης του θέματος διεξήχθησαν ημι-δομημένες συνεντεύξεις με δώδεκα σχολικούς συμβούλους και δεκατρείς διευθυντές εκπαίδευσης (πρωτοβάθμιας και δευτεροβάθμιας) από τους Νομούς Έβρου, Ροδόπης, Ξάνθης, Καβάλας, Δράμας και Θεσσαλονίκης. Έγινε προσπάθεια να διερευνηθούν οι απόψεις αυτών των στελεχών εκπαίδευσης ως προς τη μεταξύ τους συνεργασία και να διαφανεί η επικρατούσα κατάσταση αναφορικά με το υπό συζήτηση αντικείμενο, να εντοπιστούν οι λόγοι που τους ωθούν στη συνεργασία ή τους αποτρέπουν από αυτήν, οι παράγοντες που ευνοούν ή δυσχεραίνουν την ανάπτυξη συνεργασίας και οι ενέργειες στις οποίες προβαίνουν, ώστε να την επιτύχουν. Η παρούσα θεωρητική και εμπειρική μελέτη έδειξε ότι η σπουδαιότητα της συνεργασίας είναι αναμφισβήτητη και η ανάπτυξή της αναγκαία για την ποιοτική αναβάθμιση της εκπαίδευσης.
description: The topic which the present theoretical and practical study deals with is the collaboration between the educational staff, particularly school advisors and educational directors of both school levels, that is primary and secondary schools. The main purpose of this study was to research to what extent the collaboration between educational directors and school advisors exists and if so to what extent this contributes to the qualitative upgrade of education. Within the framework of the practical study of the topic, semi-structured interviews were conducted with twelve school advisors and thirteen educational directors (primary and secondary schools) from the prefectures of Evros, Rodopi, Xanthi, Kavala, Drama and Thessaloniki. Efforts were made in order to research the views of this educational staff concerning the collaboration among them and to reveal the existing situation in reference to the object in question, to detect the reasons which impel them to collaborate or deter them from it, the factors that encourage or impede the development of collaboration and the efforts they make in order to succeed. The present theoretical and practical study revealed that the importance of collaboration is inarguable and its development is highly necessary for the qualitative upgrade of education.
Environmental Effects of Dark Matter Haloes: The Clustering-Substructure relation of Group-size Haloes
Creators: name: Espino-Briones, N.
name: Plionis, M.
name: Ragone-Figueroa, C.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We estimate the two-point correlation function of dark matter haloes, with masses >10^{13} h^{-1} Mo, that have or not significant substructure. The haloes are identified with a friends of friends algorithm in a large LCDM simulation at two redshift snapshots (z=0 and 1), while halo substructure is determined using an observationally driven method. We find in both epochs a clear and significant signal by which haloes with substructure are more clustered than those with no-substructure. This is true for all the considered halo mass ranges, although for the highest halo masses the signal is noisy and present only out to ~20 h^{-1} Mpc. There is also a smooth increase of the halo correlation length with increasing amplitude of the halo substructure. We also find that substructured haloes are typically located in high-density large-scale environments, while the opposite is true for non-substructured haloes. If the haloes found in high-density regions have a relatively earlier formation time, as suggested by recent works, then they do indeed have more time to cluster than haloes, of a similar mass, which form later in the low-density regions. In such a case one would have naively expected that the former (earlier formed) haloes would typically be dynamically more relaxed than the latter (later formed). However, the higher merging and interaction rate,expected in high-density regions, could disrupt their relatively relaxed dynamical state and thus be the cause for the higher fraction of haloes with substructure found in such regions.
description: ApJ. Letters (accepted)
Downfolding the Su-Schrieffer-Heeger model
Creators: name: Schobert, Arne
name: Berges, Jan
name: Wehling, Tim
name: van Loon, Erik
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Charge-density waves are responsible for symmetry-breaking displacements of atoms and concomitant changes in the electronic structure. Linear response theories, in particular density-functional perturbation theory, provide a way to study the effect of displacements on both the total energy and the electronic structure based on a single ab initio calculation. In downfolding approaches, the electronic system is reduced to a smaller number of bands, allowing for the incorporation of additional correlation and environmental effects on these bands. However, the physical contents of this downfolded model and its potential limitations are not always obvious. Here, we study the potential-energy landscape and electronic structure of the Su-Schrieffer-Heeger (SSH) model, where all relevant quantities can be evaluated analytically. We compare the exact results at arbitrary displacement with diagrammatic perturbation theory both in the full model and in a downfolded effective single-band model, which gives an instructive insight into the properties of downfolding. An exact reconstruction of the potential-energy landscape is possible in a downfolded model, which requires a dynamical electron-biphonon interaction. The dispersion of the bands upon atomic displacement is also found correctly, where the downfolded model by construction only captures spectral weight in the target space. In the SSH model, the electron-phonon coupling mechanism involves exclusively hybridization between the low- and high-energy bands and this limits the computational efficiency gain of downfolded models.
description: Submission to SciPost. Python file to generate the plots included in the arxiv source
Experimental Results and Analytical Predictions of EHL Film Thickness
Creators: name: Pierre, Chaomleffel Jean
name: Gérard, Dalmaz
name: Vergne, Philippe
Publisher: name: arXiv
Year: 2007
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: In this work, we consider several types of lubricants - including non-Newtonian fluids - that were studied under various operating conditions leading us to explore a wide range of dimensionless parameters. The experimental results are compared with predictions given by the usual analytical EHL relationships and by more recently developed models. This broad comparison conducted with particular emphasis on minimum film thickness (hm) showed a fair agreement between experimental data and a few predictions including some obtained from extended models. Commonly used elasto-hydrodynamic lubrication (EHL) models did not systematically gave accurate hm estimation, whereas minimum film thickness not only is a yield value but also serves as a key parameter in estimating lubrication regimes.
Density of states and supercurrent in diffusive SNS junctions: role of nonideal interfaces and spin-flip scattering
Creators: name: Hammer, J. C.
name: Cuevas, J. C.
name: Bergeret, F. S.
name: Belzig, W.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We present a theoretical study of the density of states and supercurrent in diffusive superconductor-normal metal-superconductor (SNS) junctions. In particular, we study the influence on these two equilibrium properties of both an arbitrary transparency of the SN interfaces and the presence of spin-flip scattering in the normal wire. We show that the minigap that is present in the spectrum of the diffusive wire is very sensitive to the interface transmission. More mportantly, we show that at arbitrary transparency the minigap replaces the Thouless energy as the relevant energy scale for the proximity effect, determining for instance the temperature dependence of the critical current. We also study in detail how the critical current is suppressed by the effect of spin-flip scattering, which can be due to either magnetic impurities or, under certain circumstances, to an external magnetic field. Our analysis based on the quasiclassical theory of diffusive superconductors can be very valuable to establish quantitative comparisons between experiment and theory.
description: 12 pages, 13 figures
Engaging stakeholders to improve social validity: intervention priorities for students with complex communication needs
Creators: name: Biggs, Elizabeth E.
name: Hacker, Rebecca
Publisher: name: Taylor & Francis
Year: 2021
Subjects: subject: Medicine
subject: Sociology
subject: FOS: Sociology
subject: 69999 Biological Sciences not elsewhere classified
subject: FOS: Biological sciences
subject: Science Policy

description: Many factors impact intervention implementation in everyday practice, including the social validity of these interventions. As a way of addressing social validity, this study aimed to understand the perspectives of multiple stakeholders of school-aged children and adolescents who use aided and unaided augmentative and alternative communication (AAC) on their key intervention priorities for these children. Semi-structured interviews were conducted with 19 parents and professionals, which included special education teachers, paraprofessionals, and speech-language pathologists (SLPs). Qualitative content analysis focused on (a) identifying a framework of intervention priorities for children with complex communication needs and (b) understanding stakeholders’ underlying values and attitudes that influenced perceptions about these priorities. Participants shared many intervention priorities and several core values. These intervention priorities included approaches focused on improving children’s intrinsic abilities (i.e., skills-focused) and on improving children’s extrinsic supports and opportunities (i.e., environment-focused). However, participants often portrayed diverging attitudes about different aspects of intervention, particularly self-efficacy (e.g., persistence in the face of challenges; confidence about inclusive education) and perceptions of students (e.g., keeping high expectations). These findings have important implications for practice and future research related to how attention to social validity can help bridge the research-to-practice gap.
Coulomb analogy for nonhermitian degeneracies near quantum phase transitions
Creators: name: Cejnar, P.
name: Heinze, S.
name: Macek, M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: Mathematical Physics (math-ph)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: Degeneracies near the real axis in a complex-extended parameter space of a hermitian Hamiltonian are studied. We present a method to measure distributions of such degeneracies on the Riemann sheet of a selected level and apply it in classification of quantum phase transitions. The degeneracies are shown to behave similarly as complex zeros of a partition function.
description: 4 pages
title: Personalmanagement im Allgemeinen Sozialen Dienst (ASD). Zwischenergebnisse eines Forschungsprojekts an der Fachhochschule Münster, Fachbereich Sozialwesen. Vortrag auf dem ASD-Bundeskongress. Hamburg
Creators: name: Pamme, Hildegard, Merchel, Joachim, Khalaf, Adam
Publisher: name: FH Münster
Year: 2011
Subjects: subject: 300 Sozialwissenschaften

description: Personalmanagement im Allgemeinen Sozialen Dienst
title: Addressing the Sense of Touch in Online Marketing: Conceptual Developments and Empirical Investigations
title: Die Ansprache des Tastsinns im Online-Marketing: Konzeption und empirische Untersuchung
Creators: name: Kubesch, Daniel
Publisher: name: Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Year: 0
Subjects: subject: sensory marketing
subject: haptics
subject: consumer behavior
subject: DDC Classification::6 Technik, Medizin, angewandte Wissenschaften :: 65 Management, Öffentlichkeitsarbeit :: 658 Allgemeines Management

description: Since the early 2000s, sensory marketing research has made great progress in understanding how the human sense of touch influences consumer behavior (e.g., Marlow and Jansson-Boyd 2011; Peck and Childers 2003; Peck and Shu 2009; Peck and Wiggins 2006; Ringler et al. 2019). Many successful companies, such as Ikea and Apple, have also begun to leverage the potential of haptic perception, for example by actively encouraging consumers to touch products in their retail spaces (Hultén 2020). Parallel to this development, the Internet, which is typically limited to visual and auditory stimuli, has gained enormous importance as a sales and communication channel. To differentiate themselves in the increasingly competitive e-commerce environment through pleasant and multisensory online experiences, companies are starting to look for ways to haptically engage consumers online as well (Bleier, Harmeling, and Palmatier 2019; Petit, Velasco, and Spence 2019). Against this background, this dissertation presents three independent studies that provide insight into how the sense of touch can be addressed in online marketing. In doing so, this dissertation offers several important implications for online marketing research and practice.
description: Seit den frühen 2000er Jahren hat die Forschung zum sensorischen Marketing große Fortschritte beim Verständnis der Auswirkungen des menschlichen Tastsinns auf das Konsumentenverhalten erzielt (z. B. Marlow und Jansson-Boyd 2011; Peck und Childers 2003; Peck und Shu 2009; Peck und Wiggins 2006; Ringler et al. 2019). Viele erfolgreiche Unternehmen wie Ikea und Apple nutzen mittlerweile das Potenzial der haptischen Wahrnehmung, indem sie Konsumenten beispielsweise aktiv dazu ermutigen, Produkte in ihren Filialen zu berühren (Hultén 2020). Parallel zu dieser Entwicklung hat das Internet, das normalerweise auf visuelle und auditive Reize beschränkt ist, enorme Bedeutung als Vertriebs- und Kommunikationskanal gewonnen. Um sich im zunehmenden Wettbewerb im E-Commerce mittels angenehmer und multisensorischer Online-Erlebnisse zu differenzieren, suchen Unternehmen verstärkt nach Möglichkeiten, Konsumenten auch online haptisch anzusprechen (Bleier, Harmeling und Palmatier 2019; Petit, Velasco und Spence 2019). Vor diesem Hintergrund werden in dieser Dissertation drei unabhängige Studien vorgestellt, die Erkenntnisse liefern, wie der Tastsinn durch das Online-Marketing angesprochen werden kann. Dabei zeigt die Dissertation mehrere wichtige Implikationen für Forschung und Praxis im Bereich des Onlinemarketings auf.
Planar solutions of higher-spin theory I: free field level
Creators: name: Didenko, V. E.
name: Korybut, A. V.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Many black hole solutions of General Relativity are known to be linearly exact. This opens a way to study them in gauge theories that apart from gravity contain fields of higher spin $s>2$. Starting with a black brane in $AdS_4$ we find its free field higher-spin generalization that respects static and planar symmetry for all bosonic gauge fields $s\geq 0$. The solution is found for both the higher-spin curvatures and potentials in the form suitable for further non-linear analysis and satisfies the multi copy relation.
description: 32 pages, minor corrections, citations added, replaced with the journal version
Injection of Positrons into a Dense Electron Cloud in a Magnetic Dipole Trap
Creators: name: Singer, M.
name: Stoneking, M. R.
name: Stenson, E. V.
name: Deller, A.
name: Card, A.
name: Nißl, S.
name: Horn-Stanja, J.
name: Pedersen, T. Sunn
name: Saitoh, H.
name: Hugenschmidt, C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The creation of an electron space charge in a dipole magnetic trap and the subsequent injection of positrons has been experimentally demonstrated. Positrons (5eV) were magnetically guided from their source and injected into the trapping field generated by a permanent magnet (0.6T at the poles) using a cross field E $\times$ B drift, requiring tailored electrostatic and magnetic fields. The electron cloud is created by thermionic emission from a tungsten filament. The maximum space charge potential of the electron cloud reaches -42V, which is consistent with an average electron density of ($4 \pm 2$) $\times 10^{12}$ $\text{m}^{-3}$ and a Debye length of ($2 \pm 1$) $\text{cm}$. We demonstrate that the presence of this space potential does not hamper efficient positron injection. Understanding the effects of the negative space charge on the injection and confinement of positrons represents an important intermediate step towards the production of a confined electron-positron pair plasma.
Characterization of Lignin Compounds at the Molecular Level
Creators: name: Zhang, Ruochun
name: Qi, Yulin
name: Ma, Chao
name: Ge, Jinfeng
name: Hu, Qiaozhuan
name: Yue, Fu-Jun
name: Li, Si-Liang
name: Volmer, Dietrich
Publisher: name: Humboldt-Universität zu Berlin
Year: 2021
Subjects: subject: lignin
subject: mass spectrometry
subject: ionization
subject: data processing
subject: structural information
subject: 540 Chemie und zugeordnete Wissenschaften

description: Lignin is the second most abundant natural biopolymer, which is a potential alternative to conventional fossil fuels. It is also a promising material for the recovery of valuable chemicals such as aromatic compounds as well as an important biomarker for terrestrial organic matter. Lignin is currently produced in large quantities as a by-product of chemical pulping and cellulosic ethanol processes. Consequently, analytical methods are required to assess the content of valuable chemicals contained in these complex lignin wastes. This review is devoted to the application of mass spectrometry, including data analysis strategies, for the elemental and structural elucidation of lignin products. We describe and critically evaluate how these methods have contributed to progress and trends in the utilization of lignin in chemical synthesis, materials, energy, and geochemistry.
Visualization, Exploration and Data Analysis of Complex Astrophysical Data
Creators: name: Comparato, Marco
name: Becciani, Ugo
name: Costa, Alessandro
name: Larsson, Bjorn
name: Garilli, Bianca
name: Gheller, Claudio
name: Taylor, John
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In this paper we show how advanced visualization tools can help the researcher in investigating and extracting information from data. The focus is on VisIVO, a novel open source graphics application, which blends high performance multidimensional visualization techniques and up-to-date technologies to cooperate with other applications and to access remote, distributed data archives. VisIVO supports the standards defined by the International Virtual Observatory Alliance in order to make it interoperable with VO data repositories. The paper describes the basic technical details and features of the software and it dedicates a large section to show how VisIVO can be used in several scientific cases.
description: 32 pages, 15 figures, accepted by PASP
Augur: Aiding Malware Detection Using Large-Scale Machine Learning
Creators: name: Boshmaf, Yazan
name: Ripeanu, Matei
name: Beznosov, Konstantin
name: Zeeuwen, Kyle
name: Cornell, David
name: Samosseiko, Dmitry
Publisher: name: Zenodo
Year: 2012
Subjects: Malware Detection
Machine Learning

description: We present Augur: a large-scale machine learning system that uses malware static and dynamic analyses to predict the maliciousness of new files. Unlike other machine learning-based malware detection systems, Augur utilizes existing knowledge engineering performed by analysts and uses static and dynamic file properties (called Genes and Phenoms, respectively) as prominent predictive features. Augur can be deployed along side existing detection systems (e.g., an expert system) in order to achieve faster reactions to suspicious files at the endpoint, and to automatically generate effective signatures of new, unseen before malware.
Effective Spin Foam Models for Lorentzian Quantum Gravity
Creators: name: Asante, Seth K.
name: Dittrich, Bianca
name: Padua-Arguelles, José
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Making the Lorentzian path integral for quantum gravity well-defined and computable has been a long standing challenge. In this work we adopt the recently proposed effective spin foam models to the Lorentzian case. This defines a path integral over discrete Lorentzian quantum geometric configurations, which include metric and torsion degrees of freedom. The torsion degrees of freedom arise due to an anomaly, which is parametrized by the Barbero--Immirzi parameter. Requiring a semi-classical regime constrains this parameter, but the precise bound has to be determined by probing the dynamics. The effective models provide the computationally most efficient spin foam models yet, which allows us to perform first tests for determining the semi-classical regime. This includes explorations specific to the Lorentzian case, e.g. investigating quantum geometries with null lengths and null areas as well as geometries that describe a change of spatial topology.
description: 34 pages, 15 figures (Accepted to Classical and Quantum Gravity Journal)
Regular and in-plane skyrmions and antiskyrmions from boundary instabilities
Creators: name: Sandhoefner, Shane
name: Raeliarijaona, Aldo
name: Nepal, Rabindra
name: Snyder-Tinoco, Dalton
name: Kovalev, Alexey A.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We formulate a theory of skyrmion and antiskyrmion generation using magnetic field and charge current pulses. We show that the topological defect can be created at an edge of a system with Dzyaloshinskii-Moriya interaction (DMI) as well as at a boundary between regions with different DMI. We consider both perpendicular and in-plane (also known as magnetic bimerons) versions of skyrmions and antiskyrmions. We show that the magnetization twist in the vicinity of an edge or a boundary is described by a kink solution, the presence of which can instigate the generation of topological defects. We study the collective excitations of magnetization analytically and numerically, and demonstrate that under application of magnetic field and charge current pulses the magnon modes localized near boundaries can develop instabilities leading to the formation of skyrmions or antiskyrmions. Due to the skyrmion and antiskyrmion Hall effects, a properly chosen current direction can push the topological defects away from the boundary, thus facilitating their generation.
description: 10 pages, 10 figures
On Brownian flights
Creators: name: Batakis, Athanasios
name: Levitz, Pierre
name: Zinsmeister, Michel
Publisher: name: arXiv
Year: 2007
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics
subject: 60J60, 60J45, 31B20, 82C70

description: Let K be a compact subset of ${\mathbb R}^n$. We choose at random with uniform law a point at distance $ε$ of K and start a Brownian motion (BM) from this point. We study the probability that this BM hits K for the first time at a distance $\geq r$ from the starting point.
ESREDA 65 SEMINAR Program
Creators: name: Konstantinidou, Myrto
Publisher: name: Zenodo
Year: 2025

description: This is the program of the 65th ESReDA Seminar "From risk imagination to safety intervention -  Managing risks with knowledge" that was held in Athens on November 14th - 15th, 2024 at the premises of NCSR Demokritos, coorganised by ESReDA and NCSR Demokritos and sponsored by ESRA and HELLENIQ ENERGY.
Shock waves in tidally compressed stars by massive black holes
Creators: name: Brassart, M.
name: Luminet, J. -P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We interest in the case of a main-sequence star deeply penetrating within the tidal radius of a massive black hole. We focus on the compression phase leading to a so-called pancake configuration of the star at the instant of maximal compression. The aim is to study the tidal compression process paying particular attention to the development of shock waves;to deduce reliable estimates of the thermodynamical quantities involved in the pancake star; and to solve a controversy about whether or not thermonuclear reactions can be triggered in the core of a tidally compressed star. We have set up a one-dimensional hydrodynamical model well-adapted to the geometry of the problem. Based on the high-resolution shock-capturing Godunov-type approach, it allows to study the compression phase undergone by the star in the direction orthogonal to its orbital plane. We show the existence of two regimes depending on whether shock waves develop before or after the instant of maximal core compression. In both cases we confirm high compression and heating factors in the stellar core able to trigger a thermonuclear explosion. Moreover, we show that the shock waves carry outwards a brief but very high peak of temperature from the centre to the surface of the star. We tentatively conclude that the phenomenon could give rise to hard electromagnetic radiation, to be compared to some X-ray flares already observed in some galactic nuclei harbouring massive black holes. Finally, we estimate that the rate of pancake stars should be about $10^{-5}$ per galaxy per year. If generated in hard X- or $γ$-ray band, several events of this kind per year should be detectable within the full observable universe.
description: 19 pages, 38 figures, 7 tables; v2 : corrected to match version accepted in Astron. Astrophys. Tables and references added, new simulations also performed for adiabatic index 4/3
title: Научный архив Виктора Максимовича Жирмунского как автобиография. По материалам архивов Российской Академии Наук в Санкт-Петербурге
Creators: name: Naidich, Larisa
name: Svetozarova, Natal’ia
Publisher: name: AvtobiografiЯ
Year: 2020

description: The article examines the dialectological and folklore fieldwork organized between 1924 -1930 by the prominent linguist and literary scholar V. M. Zhirmunsky. The fieldwork has been conducted in the German colonies of the Southern USSR (Ukraine, Сremea, Transcaucasia), as well as in the Leningrad region. Still unpublished field materials are stored at the St.-Petersburg’s Division of Russian Academy of Sciences Archive and in Archive of the Institute of Russian Literature (Pushkinskiy Dom). Inter alia, these materials contain field reports, which describe noteworthy details on the goals, participants, collected data, and the itineraries of the aforementioned expeditions. These valuable materials shed light upon some understudied aspects of Zhirmunsky’s life and work.
Metagratings for Perfect Mode Conversion in Rectangular Waveguides: Theory and Experiment
Creators: name: Killamsetty, Vinay Kumar
name: Epstein, Ariel
Publisher: name: arXiv
Year: 2021
Subjects: subject: Applied Physics (physics.app-ph)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We present a complete design scheme, from theoretical formulation to experimental validation, exploiting the versatility of metagratings (MGs) for designing a rectangular waveguide (RWG) $\mbox{TE}_{10}$ - $\mbox{TE}_{20}$ mode converter (MC). MG devices, formed by sparse periodically positioned polarizable particles (meta-atoms), were mostly used to date for beam manipulation applications. In this paper, we show that the appealing diffraction engineering features of the MGs in such typical free-space periodic scenarios can be utilized to efficiently mould fields inside waveguides (WGs). In particular, we derive an analytical model allowing harnessing of the MG concept for realization of perfect mode conversion in RWGs. Conveniently, the formalism considers a printed-circuit-board (PCB) MG terminating the RWG, operating as a reflect-mode MC. Following the typical MG synthesis approach, the model directly ties the meta-atom position and geometry with the modal reflection coefficients, enabling resolution of the detailed fabrication-ready design by enforcement of the functionality constraints: elimination of the fundamental $\mbox{TE}_{10}$ reflection and power conservation (passive lossless MG). This reliable semianaltyical scheme, verified via full-wave simulations and laboratory measurements, establishes a simple and efficient alternative to common RWG MCs, typically requiring challenging deformation of the WG designed through time-consuming full-wave optimization. In addition, it highlights the immense potential MGs encompass for a wide variety of applications beyond beam manipulation.
description: 17 pages, 10 figures
$L^p$-Spectral theory of locally symmetric spaces with $Q$-rank one
Creators: name: Weber, Andreas
Publisher: name: arXiv
Year: 2007
Subjects: subject: Spectral Theory (math.SP)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 58J50, 11F72

description: We study the $L^p$-spectrum of the Laplace-Beltrami operator on certain complete locally symmetric spaces $M=Γ\backslash X$ with finite volume and arithmetic fundamental group $Γ$ whose universal covering $X$ is a symmetric space of non-compact type. We also show, how the obtained results for locally symmetric spaces can be generalized to manifolds with cusps of rank one.
Nitrogen sources and budgets of cereal–legume intercrops
Creators: name: Krähenbühl, Patrick
Publisher: name: Zenodo
Year: 2020

description: The aim of this master’s thesis is to find out whether the complementary use of mineral soil nitrogen and atmospheric nitrogen increases the grain yield of annual cereal-legume intercrops. Furthermore, this thesis aims to assess how nitrogen complementarity influences soil surface nitrogen budgets of cereal–legume intercrops.
Zeeman ratchets: pure spin current generation in mesoscopic conductors with non-uniform magnetic fields
Creators: name: Scheid, Matthias
name: Bercioux, Dario
name: Richter, Klaus
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We consider the possibility to employ a quantum wire realized in a two-dimensional electron gas (2DEG) as a spin ratchet. We show that a net spin current without accompanying net charge transport can be induced in the nonlinear regime by an unbiased external driving via an ac voltage applied between the contacts at the ends of the quantum wire. To achieve this we make use of the coupling of the electron spin to inhomogenous magnetic fields created by ferromagnetic stripes patterned on the semiconductor heterostructure that harbours the 2DEG. Using recursive Green function techniques we numerically study two different setups, consisting of one and two ferromagnetic stripes, respectively.
description: 24 pages, 10 figures, as published in the New Journal of Physics - Focus Issue on Spintronics in reduced dimensions
Congruences for dimensions of spaces of Siegel cusp forms and $4$-core partitions
Creators: name: Ray, Chiranjit
name: Roy, Manami
name: Yi, Shaoyun
Publisher: name: arXiv
Year: 2021
Subjects: subject: Number Theory (math.NT)
subject: FOS: Mathematics
subject: 11F46, 11P83

description: Using the relationship between Siegel cusp forms of degree $2$ and cuspidal automorphic representations of $\mathrm{GSp}(4,\mathbb{A}_{\mathbb{Q}})$, we derive some congruences involving dimensions of spaces of Siegel cusp forms of degree $2$ and the class number of $\mathbb{Q}(\sqrt{-p})$. We also obtain some congruences between the $4$-core partition function $c_4(n)$ and dimensions of spaces of Siegel cusp forms of degree $2$.
description: Some minor changes. Published online in The Ramanujan Journal
POTENCIALIDADES DAS METODOLOGIAS ATIVAS NO ENSINO E APRENDIZAGEM
Creators: name: MORORO, ANTONIA
Publisher: name: figshare
Year: 2024
Subjects: classificationCode: 399999
subject: Other education not elsewhere classified

description: As metodologias ativas de ensino têm ganhado destaque no cenário educacional por promoverem uma aprendizagem mais dinâmica, participativa e centrada no aluno. Diferentes de abordagens tradicionais, essas metodologias envolvem o aluno como protagonista do processo de construção do conhecimento, incentivando a colaboração, o pensamento crítico e a resolução de problemas. Objetivo: Analisar as potencialidades das metodologias ativas no processo de ensino e aprendizagem, destacando seus impactos no engajamento dos estudantes, na aquisição de habilidades cognitivas e socioemocionais e na melhoria dos resultados educacionais. Metodologia: Foi realizada uma revisão bibliográfica de estudos recentes sobre o uso de metodologias ativas, como a sala de aula invertida, aprendizagem baseada em projetos e estudos de caso. A análise incluiu a revisão de artigos científicos, relatórios e estudos de caso em diferentes níveis de ensino, desde o fundamental até o superior. Resultados e Discussão: Os resultados mostram que as metodologias ativas proporcionam um ambiente de aprendizagem mais colaborativo e interativo. Alunos expostos a essas práticas demonstraram maior envolvimento, autonomia e capacidade de resolver problemas complexos. Observou-se que essas metodologias favorecem a personalização do aprendizado, atendendo às necessidades individuais dos estudantes e promovendo o desenvolvimento de competências essenciais, como a comunicação, o trabalho em equipe e o pensamento crítico. No entanto, desafios como a formação docente e a infraestrutura adequada precisam ser superados para a implementação eficaz dessas abordagens. Conclusão: As metodologias ativas apresentam grande potencial para transformar o ensino, promovendo uma aprendizagem mais significativa e adaptada às exigências do mundo contemporâneo. Embora existam barreiras para sua ampla adoção, os benefícios observados em termos de engajamento e desenvolvimento de competências justificam investimentos na formação de professores e na criação de ambientes propícios para essas práticas.
Yield design formulation for porous media subjected to flow, using approximate pressure field. Calcul à la rupture en présence d'un écoulement : formulation cinématique avec un champ de pression approché
Creators: name: Corfdir, Alain
Publisher: name: arXiv
Year: 2007
Subjects: subject: Classical Physics (physics.class-ph)
subject: FOS: Physical sciences

description: Yield design formulation for porous media subjected to flow, using approximate pressure field. We attempt here to use the kinematic method of yield design in the case of a porous medium subjected to flow (with or without free surface), without looking for the exact solution of the pressure field. The method proposed here is based on the use of approximate pressure fields. In this paper, we show how, under different conditions concerning the yield criterion and the velocity field, the use of such approximate fields allows to obtain a necessary condition for stability without having to find the real pressure field. Nous cherchons ici à utiliser la méthode cinématique du calcul à la rupture dans le cas d'un milieu poreux soumis à un écoulement avec ou sans surface libre sans connaître la solution exacte du champ de pression. La méthode proposée ici repose sur l'utilisation de champs de pression approchés par défaut. Nous montrerons comment sous certaines conditions portant sur le critère de résistance et sur le champ de vitesse utilisé, l'utilisation de tels champs de pression approchés permet d'obtenir une condition nécessaire de stabilité sans avoir à déterminer exactement l'écoulement.
Investigation of alpha particle induced reactions on natural silver in the 40-50 MeV energy range
Creators: name: Ditrói, F.
name: Takács, S.
name: Haba, H.
name: Komori, Y.
name: Aikawa, M.
name: Saito, M.
name: Murata, T.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Natural silver targets have been irradiated by using a 50 MeV alpha-particle beam in order to measure the activation cross sections of radioisotopes in the 40-50 MeV energy range. Among the radio-products there are medically important isotopes such as $^{110m}$In and $^{111}$In. For optimizing the production of these radioisotopes and regarding their purity and specific activity the cross section data for every produced radioisotope are important. New data are measured in this energy range and the results of some previous measurements have been confirmed. Physical yield curves have been calculated by using the new cross section data completed with the results from the literature.
title: От curriculum vitae к автобиографии: Вальмар Адамс (1899-1993)
Creators: name: Shor, Tatiana
Publisher: name: AvtobiografiЯ
Year: 2020

description: Estonian poet and essayist, philologist, university teacher, bilingual and a bright personality Valmar (Vladimir Karl Moritz Alexander) Adams wrote many СVs and autobiographies over his long life. He was born at the turn of the century, was a direct witness to the European turmoil of the 20th century and is an unique example of both business and artistic autobiographical genres in completely opposed cultural contexts. A citizen of the imperial Russia and of the limitrophic state of the Estonian Republic and the Estonian SSR, then a citizen of the Reich Commissariat of Ostland within the framework of the German Reich, then a citizen of the USSR and again the Republic of Estonia - these are the main social roles that Adams had to comprehend and reflect on in his autobiographies at different periods. Yuri Lotman wrote about his colleague: “Valmar Adams is a man of versatile giftedness. It is difficult to describe him briefly. I once advised him to write a play where the characters would be the five sides of himself”. In the current article these roles of Adams are revealed based on documents and autobiographies from archives of the Literary Museum of Tartu, University of Tartu, and the KGB.
Detecting synchronization clusters in multivariate time series via coarse-graining of Markov chains
Creators: name: Allefeld, Carsten
name: Bialonski, Stephan
Publisher: name: arXiv
Year: 2007
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: Synchronization cluster analysis is an approach to the detection of underlying structures in data sets of multivariate time series, starting from a matrix R of bivariate synchronization indices. A previous method utilized the eigenvectors of R for cluster identification, analogous to several recent attempts at group identification using eigenvectors of the correlation matrix. All of these approaches assumed a one-to-one correspondence of dominant eigenvectors and clusters, which has however been shown to be wrong in important cases. We clarify the usefulness of eigenvalue decomposition for synchronization cluster analysis by translating the problem into the language of stochastic processes, and derive an enhanced clustering method harnessing recent insights from the coarse-graining of finite-state Markov processes. We illustrate the operation of our method using a simulated system of coupled Lorenz oscillators, and we demonstrate its superior performance over the previous approach. Finally we investigate the question of robustness of the algorithm against small sample size, which is important with regard to field applications.
description: Follow-up to arXiv:0706.3375. Journal submission 9 Jul 2007. Published 19 Dec 2007
"Przegląd Klasyczny"
Creators: name: Lewartowicz, Anna
Year: 2018

description: Rocznik wydawany przez Komitet Nauk o Kulturze Antycznej Polskiej
 Akademii Nauk poświęcony kulturze świata starożytnego. Ukazuje się od
 1946 roku.

 "Meander" znajduje się na liście ERIH "Classical Studies" (kategoria
 NAT) i w części C wykazu czasopism MNiSW (10 pkt.).
Imaging the Ionized Disk of the High-Mass Protostar Orion-I
Creators: name: Reid, M. J.
name: Menten, K. M.
name: Greenhill, L. J.
name: Chandler, C. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We have imaged the enigmatic radio source-I (Orion-I) in the Orion-KL nebula with the VLA at 43 GHz with 34 mas angular resolution. The continuum emission is highly elongated and is consistent with that expected from a nearly edge-on disk. The high brightness and lack of strong molecular lines from Orion-I can be used to argue against emission from dust. Collisional ionization and H-minus free-free opacity, as in Mira variables, require a central star with >10^5 Lsun, which is greater than infrared observations allow. However, if significant local heating associated with accretion occurs, lower total luminosities are possible. Alternatively, photo-ionization from an early B-type star and p+/e- bremsstrahlung can explain our observations, and Orion-I may be an example of ionized accretion disk surrounding a forming massive star. Such accretion disks may not be able to form planets efficiently.
description: 16 pages, 1 table, 3 figures
A closer look at observables from exclusive semileptonic $B\to(π,ρ)\ellν_{\ell}$ decays
Creators: name: Biswas, Aritra
name: Nandi, Soumitra
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: This article analyses the available inputs in $\btopilnu$ and $\btorholnu$ decays which include the measured values of differential rate in different $q^2$-bins (lepton invariant mass spectrum), lattice, and the newly available inputs on the relevant form-factors from the light-cone sum rules (LCSR) approach. We define different fit scenarios, and in each of these scenarios, we predict a few observables in the standard model (SM). For example, $R(M) =\frac{\mathcal{B}(B \to M\ell_iν_{\ell_i})}{\mathcal{B}(B\to M\ell_jν_{\ell_j})} $, $R^{\ell_i}_{\ell_j}(M) =\frac{\mathcal{B}(B\to \ell_iν_{\ell_i})}{\mathcal{B}(B \to M\ell_jν_{\ell_j})}$ with M = $π$ or $ρ$ and $\ell_{i,j} = e, μ$ or $τ$. We also discuss the new physics (NP) sensitivities of all these observables and obtain bounds on a few NP Wilson coefficients in $b\to u τν_τ$ decays using the available data. We have noted that the data at present allows sizeable NP contributions in this mode. Also, we have predicted a few angular observables relevant to these decay modes.
description: Version to be published in JHEP