cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Quantum corrections to the spin-wave spectrum of La$_2$CuO$_4$ in an external magnetic field
Creators: name: Korenblit, I. Ya.
name: Aharony, A.
name: Entin-Wohlman, O.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The effects of quantum fluctuations on the magnetic field dependence of the spin-wave gaps in the lamellar antiferromagnet La$_2$CuO$_4$ are considered. Nonlinear corrections to the spin-wave spectrum are calculated to leading order in 1/S, where $S$ is the localized spin. The nearest-neighbor exchange interactions between the Cu spins as well as the Dzyaloshinskii-Moriya interactions are taken into account. Using the experimental values of the components of the $g$-factor tensor, we get a satisfactory agreement with the experimental results for the field dependence of the gaps by Gozar {\it et al.} [Phys. Rev. Lett. {\bf 93}, 027001 (2004)], and obtain consistent values of the in-plane and inter-plane coupling constants. The field dependence of the dispersion of spin waves propagating perpendicular to the CuO$_2$ planes is also discussed.
Τεχνικές αναγνώρισης ψευδοστέρεο βίντεο
Creators: name: Κακαλέτσης, Ευστράτιος Δημητρίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Ψευδοστέρεο βίντεο
Αναγνώριση
Μετατροπή βίντεο 2D σε 3D
Fake 3D video
Recognition
2D-to-3D video conversion

description: Σκοπός της μεταπτυχιακής διατριβής εξειδίκευσης ήταν η μελέτη τεχνικών αναγνώρισης του ψευδοστέρεο βίντεο. Αρχικά δίνεται ο ορισμός του ψευδοστέρεο βίντεο που προκύπτει από τις μεθόδους μετατροπής του κλασσικού 2D βίντεο σε στερεοσκοπικό 3D. Στη συνέχεια δίνονται πληροφορίες σχετικά με την παραγωγή του πραγματικού στερεοσκοπικού βίντεο αποτέλεσμα της χρήσης των τρισδιάστατων καμερών. Ακόμη, περιγράφονται όλες οι μέθοδοι και τα εργαλεία που συμμετέχουν στην υλοποίηση των τεχνικών αναγνώρισης ψευδοστέρεο βίντεο όπως η κατάτμηση της εικόνας βασισμένη σε γράφους. Προτείνονται δύο τεχνικές αναγνώρισης ψευδοστέρεο βίντεο. Η πρώτη αναφέρεται στον υπολογισμό στατιστικών μεγεθών των τιμών της στερεοσκοπικής μετατόπισης σε σημασιολογικά αντικείμενα περιοχών ενδιαφέροντος των εικόνων που απεικονίζονται στα καρέ και η δεύτερη στην ποιοτική αξιολόγηση λωρίδων γύρω από αντικείμενα που παρουσιάζονται στις σκηνές των εν λόγω καρέ μέσω του υπολογισμού της ευκρίνειας σε αυτές τις περιοχές. Ακολουθούν τα πειράματα τα οποία εκτελέστηκαν με την εφαρμογή των προτεινόμενων αλγορίθμων καθώς και τα αποτελέσματα που προέκυψαν μετά την πειραματική αξιολόγηση. Τέλος, δίνονται τα εξαγόμενα συμπεράσματα και οι πιθανές μελλοντικές επεκτάσεις που μπορούν να γίνουν στις εν λόγω τεχνικές.
description: This master thesis aims to the development of techniques for the recognition of fake 3D videos in order to separate the fake 3D from real 3D movies and TV programmes. Firstly, the fake 3D video is determined with presenting the methods of creating it through 2D-to-3D video conversion. Secondly, the real 3D video which is created by using stereoscopic video cameras and 3D rigs, is analyzed. Furthermore, all the contributed methods for the implementation of the recognition techniques are presented such as the Efficient Graph Based Image Segmentation and the sharpness estimation metric called Cumulative Probability of Blur Detection. Two techniques of fake 3d video recognition are proposed. The first employs the statistical values (histogram and variance) calculation of semantic objects region of interest (ROI) which are presented in the disparity frames and the second is related to the quality assessment of 3D video frames through the evaluation of a sharpness metric on stripes around the same object of stereo frame pair in 3D video. Moreover, the experiments which are conducted by the application of the proposed algorithms, are presented. Finally, the future work for these algorithms is proposed.
Does General Relativity Highlight Necessary Connections in Nature?
Creators: name: Vassallo, Antonio
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: History and Philosophy of Physics (physics.hist-ph)
subject: FOS: Physical sciences

description: The dynamics of general relativity is encoded in a set of ten differential equations, the so-called Einstein field equations. It is usually believed that Einstein's equations represent a physical law describing the coupling of spacetime with material fields. However, just six of these equations actually describe the coupling mechanism: the remaining four represent a set of differential relations known as Bianchi identities. The paper discusses the physical role that the Bianchi identities play in general relativity, and investigates whether these identities -- qua part of a physical law -- highlight some kind of a posteriori necessity in a Kripkean sense. The inquiry shows that general relativistic physics has an interesting bearing on the debate about the metaphysics of the laws of nature.
description: 29 pages, 2 figures, accepted for publication in Synthese
Η Ελλάδα μέσα στα βιβλία της ελληνικής γλώσσας για τη διασπορά. Μια βιβλιογραφική έρευνα.
Creators: name: Γιαννικόπουλος, Ιωάννης Επαμεινώνδα
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Διασπορά
Εκπαίδευση
Ταυτότητα
diaspora
Education
Identity

description: Το σχολικό βιβλίο καλλιεργεί στάσεις και μεταβιβάζει αξίες και πρότυπα συμπεριφοράς στους μαθητές. Τα στοιχεία αυτά επηρεάζουν τις επιλογές και τη συμπεριφορά του ατόμου και έχουν μεγάλη σημασία τόσο για τη σχέση και επικοινωνία μεταξύ ατόμων, κοινωνικών ομάδων και λαών όσο και για τη διαμόρφωση της εθνικής και πολιτισμικής ταυτότητας. Σκοπός της παρούσας εργασίας είναι η διερεύνηση της εικόνας της Ελλάδας μέσα στα βιβλία της ελληνικής γλώσσας για τη διασπορά. Η ανάλυση από το ερευνητικό μέρος της εργασίας δείχνει ότι το νέο εκπαιδευτικό υλικό έχει διαμορφωθεί με τέτοιο τρόπο που ξεπερνά εξιδανικεύσεις του παρελθόντος ενώ είναι εμπλουτισμένο με πολλά συγχρονικά στοιχεία της Ελλάδας.
description: The school textbook nurtures attitudes and conveys values and rolemodels to the students. These elements affect the choices and behaviour of people and are of vital importance both for the relation and communication between people, social groups and ethnicities as well as the formation of national and cultural identity. The specific project aims at looking into the picture of Greece as this is depicted in the school textbooks of greek language about dispersion. The analysis from the research part of the project shows that the new educational material has been formed in such a way that is beyond idealizing the past and is also enriched with a variety of contemporary elements of Greece.
RISIS DATASETS TUTORIALS: VICO
Creators: name: Department of Management, Economics and Industrial Engineering
Publisher: name: Zenodo
Year: 2019
Subjects: RISIS datasets
tutorials
VICO
companies

description: The VICO database contains geographical, industry and accounting information on 17,854 companies founded starting from 1/1/1988, which have received at least one venture capital or angel investment starting from 1/1/1998 up to 31/12/2014, operating in 7 European countries (Belgium, Finland, France, Germany, Italy, Spain, and the United Kingdom) and Israel. Companies and investors have been involved in 28,023 investment deals. Moreover, it provides basic information on 6,839 distinct investors, of which 5,172 venture capitalists (VCs) and 1,551 business angels (BAs) (plus a small percentage of other investors, e.g. crowdfunding, private equity...). Companies and investors have been involved in 28,023 investment deals, for a total of 52,629 observations (as one or more investors can be involved in each single investment round).
Εθνικές γιορτές-πολιτιστική παράδοση και ιδιότητα του πολίτη στην πολυπολιτισμική τάξη του νηπιαγωγείου.
Creators: name: Λούβρη, Νικολέτα Μιχαήλ
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Αντιλήψεις των νηπιαγωγών
Εθνικές γιορτές
Διαπολιτισμική εκπαίδευση
Kindergarten teacher’s perceptions
National holidays
Intercultural education

description: Η παρούσα έρευνα εξετάζει τις αντιλήψεις των νηπιαγωγών για τις εθνικές γιορτές στο πολυπολιτισμικό νηπιαγωγείο. Ειδικότερα, η ερευνητική αυτή προσπάθεια είχε ως στόχο: τη διερεύνηση των απόψεων των νηπιαγωγών σχετικά με το σχεδιασμό και την υλοποίηση των εθνικών γιορτών, τις πρακτικές που ακολουθούν και κατά πόσο αυτές είναι σύμφωνες με τις αρχές της διαπολιτισμικής εκπαίδευσης, καθώς και το βαθμό εμπλοκής και συμμετοχής των παιδιών από διαφορετικά πολιτισμικά περιβάλλοντα. Για τη συλλογή των δεδομένων χρησιμοποιήθηκε η ημιδομημένη συνέντευξη σε δείγμα 30 νηπιαγωγών των νομών Θεσσαλονίκης, Ημαθίας, Πέλλας, Χαλκιδικής, Κέρκυρας και Αττικής. Η ανάλυση των δεδομένων που συλλέχθηκαν έγινε σύμφωνα με τη μέθοδο της ανάλυσης περιεχομένου. Από τα ευρήματα της μελέτης διαπιστώθηκε ότι στις περισσότερες των περιπτώσεων, οι νηπιαγωγοί υιοθετούν σύγχρονες παιδαγωγικές πρακτικές, αλλά όσον αφορά τη συμμετοχή των παιδιών από διαφορετικά πολιτισμικά περιβάλλοντα στις εθνικές γιορτές σ’ ένα μεγάλο ποσοστό δεν ακολουθούν τις αρχές της διαπολιτισμικής εκπαίδευσης, ενώ οι γνώσεις τους απέναντι στις αρχές της πολιτισμικής παιδαγωγικής και διδακτικής χαρακτηρίζονται ελλιπείς και είναι αναγκαία η άμεση αλλαγή τους.
description: The kindergarten teacher’s perceptions of the national holidays in the multicultural kindergarten compose the subject of this study. In specific, the effort of this research was intended to explore their beliefs and their teaching practices on the planning and implementation of the national holiday and examine if the practices consistent with the principles of intercultural education, as well as the participation of the students from different cultural backgrounds. For the collection of data was used the semi-structured interview and the sample constisted of 30 kindergarten teachers from Τhessaloniki, Imathia, Pella, Chalcidice, Corfu and Athens. The analysis of the collective data became according to the method of content analysis. The findings of the study indicated that in the most of cases kindergarten teachers adopt modern teaching practices, but regarding the participation of children from different cultural backgrounds in national holidays in a large proportion do not follow the principles of intercultural education and the knowledge to the principles of cultural pedagogy and teaching characterized incomplete and therefore need immediate change.
Exploring the chemistry induced by energetic processing of the H2-bearing, CO-rich apolar ice layer
Creators: name: Martin-Domenech, Rafael
name: Maksiutenko, Pavlo
name: Oberg, Karin I.
name: Rajappan, Mahesh
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Interstellar ice mantles on the surfaces of dust grains are thought to have a bi-layered structure, with a H2O-rich polar layer, covered by a CO-rich apolar layer that probably harbors H2 and other volatiles such as N2. In this work, we explore the chemistry induced by 2 keV electrons and Ly-alpha photons in H2:CO:15N2 ice analogs of the CO-rich layer when exposed to similar fluences to those expected from the cosmic-ray-induced secondary electrons and UV photons during the typical lifetime of dense clouds. Six products were identified upon 2 keV electron irradiation: CO2, C2O (and other carbon chainoxides), CH4, H2CO, H2C2O, and H15NCO. The total product abundances corresponded to 5-10% of the initial CO molecules exposed to the electron irradiation. Ly-alpha photon irradiation delivered 1-2 orders of magnitude lower yields with a similar product branching ratio, which may be due to the low UV-photon absorption cross-section of the ice sample at this wavelength. Formation of additional N-bearing species, namely C215N2 and 15NH3, was only observed in the absence of H2 and CO molecules, respectively, suggesting that reactants derived from H2 and CO molecules preferentially react with each other instead of with 15N2 and its dissociation products. In summary, ice chemistry induced by energetic processing of the CO-rich apolar ice layer provides alternative formation pathways for several species detected in the interstellar medium, including some related to the complex organic molecule chemistry. Further quantification of these pathways will help astrochemical models to constrain their relative contribution to the interstellar budget of, especially, the organic species H2CO and HNCO.
A population of compact radio variables and transients in the radio bright zone at the Galactic center observed with the Jansky Very Large Array
Creators: name: Zhao, Jun-Hui
name: Morris, Mark R.
name: Goss, W. M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Using JVLA data obtained from high-resolution observations at 5.5 GHz at multiple epochs in 2014 and 2019, we have detected a population of radio variables and transients in the radio bright zone at the Galactic center. With observations covering a sky area of 180 arcmin$^2$ at an angular resolution of 0.4 arcsec, we report new detections of 110 Galactic center compact radio (GCCR) sources with a size of $<1$ arcsec. The flux densities of GCCRs exceed 70 $μ$Jy, with at least 10$σ$ significance. Among these sources, 82 are variable or transient and 28 are non-variable. About 10\% of them are expected to be extragalactic background sources. We discuss the possible astrophysical nature of the detected sources. As compared to the Galactic disk (GD) population of normal pulsars (NPs) and millisecond pulsars (MSPs), a majority (80\%) of the GCCRs appears to fall within the high flux-density tail of the pulsar distribution, as extrapolated from a sample of NPs in the Galactic disk. However, MSPs extrapolated from the GD population are too weak to have contributed significantly to the GCCR population that have been detected. We also cross-correlated the GCCRs with X-ray sources in Chandra X-ray catalogs and found that 42 GCCRs have candidate X-ray counterparts. Most of the GCCRs having X-ray counterparts are likely to be associated with unresolved or slightly resolved radio jets launched from X-ray binaries with a compact object, either a black hole or a neutron star.
description: 20 pages, 7 figures, ApJ accepted
Amplifying variability of solar-like stars by active longitudes and nesting
Creators: name: Isik, Emre
name: Shapiro, Alexander I.
name: Solanki, Sami K.
name: Krivova, Natalie A.
Publisher: name: Zenodo
Year: 2021

description: Many solar-type stars with near-solar rotation periods exhibit much stronger variability than the Sun (Reinhold et al. 2020). Some of these stars even show very regular, sine-like light curves. Motivated by solar activity complexes, we developed a numerical model to quantify the effect of active-region (AR) nesting and active longitudes on stellar brightness variations in the rotational time scale. Modelling ARs with facular and spot components, we simulated light curves covering four years and using the Kepler passband. We found that the combined effect of the degree of nesting and the activity level, both being somewhat higher than on the Sun, can explain the whole range of observed light-curve amplitudes of solar-like stars. While nesting at random longitudes can explain variability amplitudes and light-curve morphology in many cases, active-longitude-type nesting reproduces sine-like light curves and the highest amplitude variability.
The FAMU experiment at RIKEN RAL for a precise measure of the proton radius
Creators: name: Bonesini, M.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: The goal of the FAMU experiment at RIKEN RAL is the measure of the hyperfine splitting of the ground state of the muonic hydrogen, to allow a determination of the proton Zemach radius with a precision better than $5 \times 10^{-3}$ . The comparison of this measurement with the ones done with ordinary hydrogen may help to solve the so-called "proton radius puzzle", triggered by the $6 σ$ discrepancy in the proton charge radius value as extracted from muonic Lamb shift and the value based on e-p scattering and ordinary hydrogen spectroscopy.
description: European Physical Society Conference on High Energy Physics - EPS-HEP2019 -10-17 July, 2019 Ghent, Belgium
The Initial Mass Function and Birth History of Brown Dwarfs in the Solar Neighborhood from a Volume-Limited Sample
Creators: name: Best, William
name: Sanghi, Aniket
name: Liu, Michael
name: Magnier, Eugene
name: Dupuy, Trent
Publisher: name: Zenodo
Year: 2021
Subjects: Very low mass stars
Brown dwarfs
Initial mass function

description: As the lowest-mass products of star formation, brown dwarfs are essential to understanding the history of our galaxy. To this end, a complete volume-limited sample of brown dwarfs in the solar neighborhood is critical for testing formation theories. To create such a sample, our Hawaii Infrared Parallax Program has recently measured parallaxes for 350 L and T dwarfs, the largest single batch of parallaxes for brown dwarfs to date. Using our work and literature measurements, we have constructed a volume-limited sample of brown dwarfs out to 25 pc. We augmented this with a large Keck adaptive-optics imaging campaign to establish the binary properties of the sample. We use population synthesis analysis to establish the initial mass function and birth history of substellar objects in the Solar neighborhood. We compare with IMF measurements for the solar neighborhood.
description: {"references": ["Allen et al. (2005). 2005ApJ...625..385A", "Best et al. (2021). 2021AJ....161...42B", "Burningham et al. (2013). 2013MNRAS.433..457B", "Day-Jones et al. (2013). 2013MNRAS.430.1171D", "Kirkpatrick et al. (2012). 2012ApJ...753..156K", "Kirkpatrick et al. (2021). arXiv:2011.11616", "Kroupa (2001). 2001MNRAS.322..231K", "Metchev et al. (2008). 2008ApJ...676.1281M", "Pinfield et al. (2008). 2008MNRAS.390..304P", "Reyl\u00e9 et al. (2010). 2010A&A...522A.112R", "Saumon & Marley (2008). 2008ApJ...689.1327S"]}
Pulse vaccination in the periodic infection rate SIR epidemic model
Creators: name: Jin, Zhen
name: Haque, Mainul
name: Liu, Quanxing
Publisher: name: arXiv
Year: 2006
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: A pulse vaccination SIR model with periodic infection rate $β(t)$ have been proposed and studied. The basic reproductive number $R_0$ is defined. The dynamical behaviors of the model are analyzed with the help of persistence, bifurcation and global stability. It has been shown that the infection-free periodic solution is globally stable provided $R_0 < 1$ and is unstable if $R_0>1$. Standard bifurcation theory have been used to show the existence of the positive periodic solution for the case of $R_0 \to1^+$. Finally, the numerical simulations have been performed to show the uniqueness and the global stability of the positive periodic solution of the system.
description: 17pages and 3figures, submmission to Mathematical Biosciences
Quantifying Optical Cool Dwarf Model Systematics and a New Photometric [Fe/H] Relation
Creators: name: Rains, Adam D.
name: Žerjal, Maruša
name: Ireland, Michael J.
name: Nordlander, Thomas
name: Bessell, Michael S.
name: Casagrande, Luca
name: Onken, Christopher A.
name: Joyce, Meridith
name: Kammerer, Jens
name: Abbot, Harrison
Publisher: name: Zenodo
Year: 2021
Subjects: Cool Stars on the main sequence

description: In Rains et al. 2021 (arXiv:2102.08133) we conducted a medium resolution optical (3,500 < λ < 7,000 Å) spectroscopic survey of 92 cool (3,000 ≲ Teff ≲ 4,500 K) southern TESS candidate planet hosts and 136 cool dwarf standards using WiFeS on the ANU 2.3 m Telescope. As part of our model-based fitting methodology, we conducted an investigation into MARCS model atmospheres and found they systematically overestimate flux the cooler the star and bluer the wavelength. In addition, we developed an updated photometric [Fe/H] calibration with Gaia+2MASS photometry for isolated main sequence stars precise to ±0.19 dex. This was built upon a calibration sample of 69 cool dwarfs in binary systems with a hotter FGK companion, valid from super-solar to metal poor, and over 1.51 < Gaia BP‒RP < 3.3.
X-ray bright sources in the Chandra Small Magellanic Cloud Wing Survey - detection of two new pulsars
Creators: name: McGowan, K. E.
name: Coe, M. J.
name: Schurch, M.
name: McBride, V. A.
name: Galache, J. L.
name: Edge, W. R. T.
name: Corbet, R. H. D.
name: Laycock, S.
name: Udalski, A.
name: Buckley, D. A. H.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate the X-ray and optical properties of a sample of X-ray bright sources from the Small Magellanic Cloud (SMC) Wing Survey. We have detected two new pulsars with pulse periods of 65.8 s (CXOU J010712.6-723533) and 700 s (CXOU J010206.6-714115), and present observations of two previously known pulsars RX J0057.3-7325 (SXP101) and SAX J0103.2-7209 (SXP348). Our analysis has led to three new optical identifications for the detected pulsars. We find long-term optical periods for two of the pulsars, CXOU J010206.6-714115 and SXP101, of 267 and 21.9 d, respectively. Spectral analysis of a sub-set of the sample shows that the pulsars have harder spectra than the other sources detected. By employing a quantile-based colour-colour analysis we are able to separate the detected pulsars from the rest of the sample. Using archival catalogues we have been able to identify counterparts for the majority of the sources in our sample. Combining this with our results from the temporal analysis of the Chandra data and archival optical data, the X-ray spectral analysis, and by determining the X-ray to optical flux ratios we present preliminary classifications for the sources. In addition to the four detected pulsars, our sample includes two candidate foreground stars, 12 probable active galactic nuclei, and five unclassified sources.
description: 13 pages, 7 figues, 4 tables, accepted for publication in MNRAS
Geometrical aspects of localization theory
Creators: name: Szabo, Richard Joseph
Publisher: name: University of British Columbia
Year: 2009

description: Some recent developments in topological quantum field theory have focused on localization techniques using equivariant cohomology to reduce functional integrals to finite-dimensional expressions from which physical and mathematical characteristics are readily deduced. In this thesis we examine the applicability of these localization techniques by analysing in detail the geometric constraints that these methods assume. After an extensive review of the relevant background material, we focus on the applications of equivariant localization techniques to phase space path integrals and classify the 2-dimensional Hamiltonian systems with simply-connected phase spaces to which these formalisms can be applied using their fundamental geometric constraints. We show that for maximally symmetric phase spaces the localizable Hamiltonian systems all appear in harmonic oscillator forms, while for non-homogeneous spaces the possibilities are more numerous. In the latter cases the Riemannian structures become rather complicated. We show that these systems all share the common property that their quantum dynamics can be described using coherent states, usually associated with coadjoint Lie group orbits, and we evaluate the associated character formulas. We then show how these results generalize to the case where the phase space is a multiply-connected compact Riemann surface. After discussing how the previous formalisms should be appropriately modified in this case, we show that the partition function for the localizable Hamiltonian systems describes a rich topological field theory which represents the first homology of the phase space. The coherent states in this case are also constructed and it is shown that the Hubert space is finite-dimensional. The wavefunctions carry a projective representation of the phase space homology group and describe modular invariants of the quantum theory. Finally, we discuss some geometric methods for analysing corrections to the semi-classical approximation for dynamical systems whose path integrals do not localize. We show that the usual isometric symmetry needed for localization can be replaced by a weaker conformal symmetry requirement. We then introduce an alternative method to the loop expansion for obtaining corrections to the semi-classical approximation which expresses the correction terms as Poincaré dual forms of homology cycles of the phase space.
Spike behavior in the approach to spacetime singularities
Creators: name: Garfinkle, David
name: Pretorius, Frans
Publisher: name: arXiv
Year: 2020
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We perform numerical simulations of the approach to spacetime singularities. The simulations are done with sufficient resolution to resolve the small scale features (known as spikes) that form in this process. We find an analytical formula for the shape of the spikes and show that the spikes in the simulations are well described by this formula.
Comparison of the measured atmospheric muon flux with Monte Carlo simulations for the first KM3NeT detection units
Creators: name: Kalaczyński, Piotr
name: Coniglione, Rosa
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: The KM3NeT Collaboration has successfully deployed its first detection units in the Mediterranean Sea in December 2015 (ARCA) and September 2017 (ORCA). The sample of data collected between September 2016 and March 2017 has been used to measure the atmospheric muon flux at two different depths under the sea level: about 3.5\,km with ARCA and about 2.5\,km with ORCA. The atmospheric muon flux represents an abundant signal for a neutrino telescope and can be used to test the reliability of the Monte Carlo simulation chain. In this work, the measurements are compared to Monte Carlo simulations based on MUPAGE and CORSIKA codes. Measured events and simulated events are treated using the same approach, making the comparison reliable.
description: 7 pages, 4 figures, based on Proceedings of the 36th International Cosmic Ray Conference (ICRC 2019), July 24-August 1, 2019, Madison, USA. No modifications
A catalog of 551,214 low-mass, metal-poor stars in the Local Galactic halo from Gaia EDR3
Creators: name: Kim, Bokyoung
name: Lepine, Sebastien
Publisher: name: Zenodo
Year: 2021
Subjects: Cool Stars on the main sequence
high-proper-motion stars
catalog
Galactic halo

description: We present a census of the population of local (d < 2 kpc) Galactic halo stars, based on a search of stars with large proper motions (> 40 mas/yr) from the Gaia Early Data Release 3. From this we assemble a catalog of 551,214 low-mass halo stars, for which we also derive photometric metallicity estimates. We assembled 17,803 stars as a metallicity calibration subset from various large spectroscopic surveys, such as SDSS SEGUE/APOGEE, GALAH, LAMOST, and from Hejazi et al. (2020). We expand on these results to construct a color-magnitude-metallicity grid, which can be used to estimate metallicities for all the stars using their values of MG and GRP. We find that stars in our catalog share similar kinematics as reported in recent studies of more luminous Galactic halo stars. Our sample notably shows likely new members of Gaia-Enceladus Stream of which mean photometric metallicity estimate is around -1.2 dex. We further explore how the velocity-space distribution of low-mass M stars varies with metallicity, and tentatively identify possible chemically distinct sub-populations, which could potentially be revealed in greater detail with radial velocity measurements the full Gaia Data Release 3 and from large spectroscopic surveys like SDSS-V, DESI MW survey, WEAVE, and/or 4MOST.
description: {"references": ["Ahumada, R., Allende Prieto, C., Almeida, A., et al. 2020, ApJS, 249, 3", "Buder, S., Sharma, S., Kos, J., et al. 2020, arXiv:2011.02505", "Gaia Collaboration, Prusti, T., de Bruijne, J. H. J., et al. 2016, A&A, 595, A1", "Gaia Collaboration, Brown, A. G. A., Vallenari, A., et al. 2020, arXiv:2012.01533", "Green, G. M., Schlafly, E., Zucker, C., et al. 2019, ApJ, 887, 93. doi:10.3847/1538-4357/ab5362", "Hejazi, N., Lepine, S., Homeier, D., et al. 2020, AJ, 159, 30. doi:10.3847/1538-3881/ab563c", "Majewski, S. R., Schiavon, R. P., Frinchaboy, P. M., et al. 2017, AJ, 154, 94", "Yanny, B., Rockosi, C., Newberg, H. J., et al. 2009, AJ, 137, 4377"]}
Viscosity of gauge theory plasma with a chemical potential from AdS/CFT correspondence
Creators: name: Maeda, Kengo
name: Natsuume, Makoto
name: Okamura, Takashi
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We compute the strong coupling limit of the shear viscosity for the N=4 super-Yang-Mill theory with a chemical potential. We use the five-dimensional Reissner-Nordstrom-anti-deSitter black hole, so the chemical potential is the one for the R-charges U(1)_R^3. We compute the quasinormal frequencies of the gravitational and electromagnetic vector perturbations in the background numerically. This enables one to explicitly locate the diffusion pole for the shear viscosity. The ratio of the shear viscosity eta to the entropy density s is eta/s=1/(4pi) within numerical errors, which is the same result as the one without chemical potential.
description: 11 pages, 5 figures, ReVTeX4; v2: minor improvements; v3: explanations added and improved; v4: version to appear in PRD
Probing the pathway of an ultrafast structural phase transition to illuminate the transition mechanism in Cu2S
Creators: name: Li, Junjie
name: Sun, Kai
name: Li, Jun
name: Meng, Qingping
name: Fu, Xuewen
name: Yin, Wei-Guo
name: Lu, Deyu
name: Li, Yan
name: Babzien, Marcus
name: Fedurin, Mikhail
name: Swinson, Christina
name: Malone, Robert
name: Palmer, Mark
name: Mathurin, Leanne
name: Mason, Ryan
name: Chen, Jingyi
name: Konik, Robert M.
name: Cava, Robert J.
name: Zhu, Yimei
name: Tao, Jing
Publisher: name: arXiv
Year: 2020
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: Disentangling the primary order parameter from secondary order parameters in phase transitions is critical to the interpretation of the transition mechanisms in strongly correlated systems and quantum materials. Here we present a study of structural phase transition pathways in superionic Cu2S nanocrystals that exhibit intriguing properties. Utilizing ultrafast electron diffraction techniques sensitive in both momentum-space and the time-domain, we distinguish the dynamics of crystal symmetry breaking and lattice expansion in this system. We are able to follow the transient states along the transition pathway and so observe the dynamics of both the primary and secondary order parameters. Based on these observations we argue that the mechanism of the structural phase transition in Cu2S is dominated by the electron-phonon coupling. This mechanism advances the understanding from previous results where the focus was solely on dynamic observations of the lattice expansion.
Multicolor Variability of Young Stars in the Lagoon Nebula: Driving Causes and Intrinsic Timescales
Creators: name: Venuti, Laura
name: Cody, Ann Marie
name: Rebull, Luisa M.
name: Beccari, Giacomo
name: Irwin, Mike
name: Thanvantri, Sowmya
name: Howell, Steve B.
name: Barentsen, Geert
Publisher: name: Zenodo
Year: 2021
Subjects: Young stars
Stellar systems, clusters, and associations

description: High-precision time series photometry provides a unique window into the dynamics of the inner disk regions around young stars. Exquisite surveys with CoRoT and Kepler/K2 have revealed a huge variety of photometric behaviors for young stars with disks, from purely periodic to stochastic, bursting, or dipping. By exploring the color dependence of each variability pattern, it is possible to identify the underlying physical drivers: stellar magnetic activity, star-disk interaction, variable mass accretion, rapidly evolving inner disk structures. Here, we present a new study on the time domain behavior of very young stars in the Lagoon Nebula. The region, monitored with K2, hosts a very young (~2 Myr) population distributed over a wide mass range, including dozens of OB stars. These characteristics render the region an ideal target to probe the impact of stellar mass on the dynamics of young star-disk systems at the age when planets are born. From the K2 mosaic we extracted light curves for around 300 Lagoon Nebula members, of spectral types between B and K. For the same stars, we gathered auxiliary multi-band (u,g,r,i,Halpha) photometry from the VLT Survey Telescope, to investigate the nature of the observed variability signatures. Our study reveals a clear distinction between weakly variable higher-mass stars and strongly variable lower-mass stars, with disk-related variability signatures that tend to disappear at spectral types earlier than G. These findings point to distinct magnetic field properties, and to varying physical conditions in the inner disk, for young stars of different masses. Distinct characteristic timescales of variability are found for different light curve classes, suggesting a diverse origin of the corresponding variability signatures within the star-disk environment. However, all stars exhibit the largest amount of variability on rotational (days) timescales, suggesting an overall stability of the inner disk processes over many dynamical periods.
description: {"references": ["Allen, Lori E. et al. (2004), ApJS, 154, 363", "Cody, Ann Marie et al. (2014), AJ, 147, 82", "Cody, Ann Marie et al. (2018), AJ, 156, 71", "Damiani, Francesco et al. (2019), A&A, 623, A25", "Sergison, Darryl J. et al. (2020), MNRAS, 491, 5035"]}
Sensitivity and spatial resolution of square loop SQUID magnetometers
Creators: name: Rombetto, S
name: Vettoliere, A
name: Granata, C
name: Russo, M
name: Nappi, C
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We calculate the flux threading the pick-up coil of a square SQUID magnetometer in the presence of a current dipole source. The result reproduces that of a circle coil magnetometer calculated by Wikswo with only small differences. However it has a simpler form so that it is possible to derive from it closed form expressions for the current dipole sensitivity and the spatial resolution. The results are useful to assess the overall performance of the device and to compare different designs.
The Luttinger model following a sudden interaction switch-on
Creators: name: Cazalilla, M. A.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The evolution of correlations in the \emph{exactly} solvable Luttinger model (a model of interacting fermions in one dimension) after a sudden interaction switch-on is \emph{analytically} studied. When the model is defined on a finite-size ring, zero-temperature correlations are periodic in time. However, in the thermodynamic limit, the system relaxes algebraically towards a stationary state which is well described, at least for some simple correlation functions, by the generalized Gibbs ensemble recently introduced by Rigol \emph{et al.} [cond-mat/0604476]. The critical exponent that characterizes the decay of the one-particle correlation function is different from the known equilibrium exponents. Experiments for which these results can be relevant are also discussed.
description: 4.3 pages. Typos corrected, added references
การเดินทางของคาราบาวจากยุคอุดมการณ์สู่เส้นทางทุนนิยม
Creators: name: วรัตต์ อินทสระ
name: เสรี วงษ์มณฑา
Publisher: name: วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
Year: 2550
Subjects: คาราบาว,สะท้อนสังคมไทย,ทุนนิยม,ดนตรีเพื่อชีวิต

description: 3, 3, วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
กลยุทธ์การบริหารจัดการตามกระบวนทัศน์ธรรมาภิบาลในองค์การบริหารส่วนตำบล:กรณีศึกษาเฉพาะในเขตจังหวัดภาคใต้ตอนล่างของประเทศไทย
Creators: name: สรรเสริญ อินทรัตน์
name: สุเทพ เชาวลิต
Publisher: name: วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
Year: 2550
Subjects: กลยุทธ์,ธรรมาภิบาล,องค์การบริหารส่วนตำบล,ภาคใต้ตอนล่างของประเทศไทย

description: 3, 3, วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
The Protostar in the massive Infrared Dark Cloud IRDC18223-3
Creators: name: Beuther, H.
name: Steinacker, J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: At the onset of high-mass star formation, accreting protostars are deeply embedded in massive cores made of gas and dust. Their spectral energy distribution is still dominated by the cold dust and rises steeply from near-to far-infrared wavelengths. The young massive star-forming region IRDC18223-3 is a prototypical Infrared-Dark-Cloud with a compact mm continuum core that shows no protostellar emission below 8mum. However, based on outflow tracers, early star formation activity was previously inferred for this region. Here, we present recent Spitzer observations from the MIPSGAL survey that identify the central protostellar object for the first time at 24 and 70mum. Combining the mid- to far-infrared data with previous mm continuum observations and the upper limits below 8mum, one can infer physical properties of the central source. At least two components with constant gas mass M and dust temperature T are necessary: one cold component (~15K and ~576M_sun) that contains most of the mass and luminosity, and one warmer component (>=51K and >=0.01M_sun) to explain the 24mum data. The integrated luminosity of ~177L_sun can be used to constrain additional parameters of the embedded protostar from the turbulent core accretion model for massive star formation. The data of IRDC18223-3 are consistent with a massive gas core harboring a low-mass protostellar seed of still less than half a solar mass with high accretion rates of the order 10^-4M_sun/yr. In the framework of this model, the embedded protostar is destined to become a massive star at the end of its formation processes.
description: 5 pages, 2 figures, accepted for Astrophysical Journal Letters, for a high-resolution version see http://www.mpia.de/homes/beuther/papers.html
ยุทธวิธีในการลดผลกระทบพฤติกรรมที่ไม่เหมาะสมของบุคคลที่มีชื่อเสียงในสื่อสารมวลชนต่อทุรกรรมเยาวชน
Creators: name: มาริษา สุจิตวนิช
name: เสรี วงษ์มณฑา
Publisher: name: วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
Year: 2550
Subjects: การลดผลกระทบ,พฤติกรรมที่ไม่เหมาะสม,บุคคลที่มีชื่อเสียง,ทุรกรรมเยาวชน

description: 3, 3, วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
Capillary Sorting of Particles by Dip Coating
Creators: name: Dincau, Brian M.
name: Bazant, Martin Z.
name: Dressaire, Emilie
name: Sauret, Alban
Publisher: name: arXiv
Year: 2020
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: In this letter, we describe the capillary sorting of particles by size based on dip coating. A substrate withdrawn from a liquid bath entrains a coating whose thickness depends on the withdrawal speed and the liquid properties. If the coating material contains particles, they will only be entrained when the viscous force pulling them with the substrate overcomes the opposing capillary force at the deformable meniscus. This force threshold occurs at different liquid thicknesses for particles of different sizes. Here, we show that this difference can be used to separate small particles from a mixed suspension through capillary filtration. In a bidisperse suspension, we observe three distinct filtration regimes. At low capillary numbers, Ca, no particles are entrained in the liquid coating. At high Ca, all particle sizes are entrained. For a range of capillary numbers between these two extremes, only the smallest particles are entrained while the larger ones remain in the reservoir. We explain how this technique can be applied to polydisperse suspension. We also provide an estimate of the range of capillary number to separate particles of given sizes. The combination of this technique with the scalability and robustness of dip coating makes it a promising candidate for high-throughput separation or purification of industrial and biomedical suspensions.
การพัฒนาระบบการจัดการความมั่นคงปลอดภัยบนระบบเครือข่ายคอมพิวเตอร์สำหรับมหาวิทยาลัยราชภัฏสวนดุสิต
Creators: name: จิตติมา เทียมบุญประเสริฐ
name: กว้าน สีตะธนี
Publisher: name: วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
Year: 2550
Subjects: ความมั่นคงปลอดภัย,เครือข่ายคอมพิวเตอร์,มหาวิทยาลัยราชภัฏสวนดุสิต

description: 3, 3, วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
การเปรียบเทียบประสิทธิภาพของคณะครุศาสตร์มหาวิทยาลัยราชภัฏจากผู้ประเมินหลายกลุ่ม: ผลการวิเคราะห์ประสิทธิภาพด้วยวิธีวางกรอบข้อมูล
Creators: name: รุ่งนภา ตั้งจิตรเจริญกุล
name: ศิริชัย กาญจนวาสี
name: นงลักษณ์ วิรัชชัย
Publisher: name: วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
Year: 2551
Subjects: ประสิทธิภาพของคณะครุศาสตร์,มหาวิทยาลัยราชภัฏ,การจัดการเรียนการสอน,คุณภาพนักศึกษา

description: 1, 4, วารสารวิจัย มสด สาขามนุษยศาสตร์และสังคมศาสตร์
Design of Matched Zero-Index Metamaterials Using Non-Magnetic Inclusions in Epsilon-Near-Zero (ENZ) Media
Creators: name: Silveirinha, Mario
name: Engheta, Nader
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In this work, we study the electrodynamics of metamaterials that consist of resonant non-magnetic inclusions embedded in an epsilon-near-zero (ENZ) host medium. It is shown that the inclusions can be designed in such a way that both the effective permittivity and permeability of the composite structure are simultaneously zero. Two different metamaterial configurations are studied and analyzed in detail. For a particular class of problems, it is analytically proven that such matched zero-index metamaterials may help improving the transmission through a waveguide bend, and that the scattering parameters may be completely independent of the specific arrangement of the inclusions and of the granularity of the crystal. The proposed concepts are numerically demonstrated at microwaves with a metamaterial realization based on an artificial plasma.
description: 38 pages, 10 Figures, under review
Collisionless shock acceleration in the corona of an inertial confinement fusion pellet with possible application to ion fast ignition
Creators: name: Boella, E.
name: Bingham, R.
name: Cairns, R. A.
name: Norreys, P.
name: Trines, R.
name: Scott, R.
name: Vranic, M.
name: Shukla, N.
name: Silva, L. O.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Two-dimensional Particle-In-Cell simulations are used to explore collisionless shock acceleration in the corona plasma surrounding the compressed core of an inertial confinement fusion pellet. We show that an intense laser pulse interacting with the long scale-length plasma corona is able to launch a collisionless shock around the critical density. The nonlinear wave travels up-ramp through the plasma reflecting and accelerating the background ions. Our results suggest that protons with characteristics suitable for ion fast ignition may be achieved in this way.
Performance of a Time-Projection-Chamber with a Large-Area Micro-Pixel-Chamber Readout
Creators: name: Miuchi, Kentaro
name: Hattori, Kaori
name: Kabuki, Shigeto
name: Kubo, Hidetoshi
name: Kurosawa, Shunsuke
name: Nishimura, Hironobu
name: Takada, Atsushi
name: Tsuchiya, Ken'ichi
name: Okada, Yoko
name: Tanimori, Toru
name: Ueno, Kazuki
Publisher: name: arXiv
Year: 2007
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: A micro time-projection-chamber (micro-TPC) with a detection volume of 23*28*31 cm^3 was developed, and its fundamental performance was examined. The micro-TPC consists of a micro pixel chamber with a detection area of 31*31 cm^2 as a two-dimensional imaging device and a gas electron multiplier with an effective area of 23*28 cm^2 as a pre-gas-multiplier. The micro-TPC was operated at a gas gain of 50,000, and energy resolutions and spatial resolutions were measured.
description: 4 pages, 7 figures, proceedings of IWORID 8
Age Spreads and Systematics in λ Orionis with Gaia DR2 and the SPOTS tracks
Creators: name: Cao, Lyra
name: Pinsonneault, Marc
name: Hillenbrand, Lynne
name: Kuhn, Michael
Publisher: name: Zenodo
Year: 2021
Subjects: Young stars
Stellar systems, clusters, and associations
Stellar parameters

description: In young pre-main sequence clusters, observations typically reveal a large luminosity spread between cluster members, which may be the result of observational errors or evolutionary processes. In this work, we attempt to constrain observational uncertainties through improved membership, extinction, empirical colors, and independent Teff information. The recent success of magnetic and spotted models in explaining stellar parameter discrepancies for eclipsing binaries and pre-main sequence stars motivates a comparison with classical models in a young cluster. We apply our open cluster-calibrated, spectral energy distribution fitting technique to pre-MS stars on a sample of selected literature and APOGEE Net Teff's. We develop a Gaussian Mixture Model for determining cluster membership with Gaia DR2 data, and apply a highly selective cut in parallax and proper motion space. After obtaining stellar luminosity and temperature for our members, we provide isochronal ages with classical stellar models as well as spotted and magnetic models. Our luminosities imply a significant luminosity spread even with star-by-star extinction. We suggest that the ages of Class II stars in our cluster appear systematically younger than the Class III stars after accounting for star-by-star extinction. We find an age of Lambda Orionis of 3.9±0.2 Myr; with empirical intrinsic colors, classical models may underestimate stellar ages by as much as 50% at these early ages, if accounting for low mass stars. With multiple families of isochrones, we suggest that the inconsistency in isochrone ages between stars of high and low mass with classical models may be improved through the introduction of spots or magnetic effects in stellar evolution.
description: Supported by NASA grant 80NSSC19K0597
The Mean Magnetic Field of HD 113816
Creators: name: Johns-Krull, Christopher M.
Publisher: name: Zenodo
Year: 2021
Subjects: Post main sequence cool stars, Young stars, Magnetic Fields

description: HD 113816 (IS Vir) is a K0 III RS CVn star. We use high resolution K band spectra obtained with the
 CHSELL spectrometer to measure the mean magnetic field across the stellar surface. Four strong Ti I
 lines provide significant sensitivity to magnetic fields, while several magnetically insensitive CO lines
 provide a check on all other line broadening mechanisms. Our initial analysis reveals a mean field of ~1
 kG across the entire stellar surface. We discuss the implications of this measurement.
description: {"references": ["Johns-Krull, C. M. (2007), ApJ, 664, 975", "Johns-Krull, C.M. & Valenti, J.A. (2000), ASPC, 198, 371", "Katz, D. et al. (2003), A&A, 397, 747", "Piskunov, N. (1999), ASSL, 243, 515"]}