cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Can slowly rotating stars sustain magnetic cycles?
Creators: name: Noraz, Quentin
name: Brun, Allan Sacha
name: Strugarek, Antoine
Publisher: name: Zenodo
Year: 2021
Subjects: Cool Stars on the main sequence

description: The solar magnetic field is generated and sustained through an internal dynamo. In stars, this process is determined by the combined action of turbulent convective motions and the differential rotation profile. It can sometimes lead to magnetic cyclic variabilities, like in the Sun with the 11 years cycle. Traces of magnetic cycles have been detected for other stars as well, ranging from a few years to a few tens of years. How are these cycles controlled?
 During their life, the rotation of stars is subject to complex evolution. Recent 3D numerical simulations of solar-like stars show that different regimes of differential rotation can be characterized with the Rossby number. In particular, anti-solar differential rotation (fast poles, slow equator) may exist for a high Rossby number (slow rotators). If this regime occurs during the main sequence, and in general for slow rotators, we may wonder how the magnetic generation through dynamo process will be impacted. In particular, can slowly rotating stars have magnetic cycles? We present a numerical multi-D study with the STELEM and ASH codes to understand the magnetic field generation of solar-like stars under various differential rotation regimes, and focus on the existence of magnetic cycles. We find that short cycles are favoured for small Rossby numbers (fast rotators), and long cycles for intermediate (solar-like) Rossby numbers. Slow rotators (high Rossby numbers) are found to produce only steady dynamo with no cyclic activity in most cases considered. Magnetic cycles can be produced with anti-solar differential rotation only if the alpha effect is fine tuned for this purpose. We conclude that slow rotating stars in the anti-solar differential rotation regime can sustain magnetic cycles only for very specific dynamo processes. A detection of magnetic cycles for such stars would therefore be a tremendous constrain on deciphering what type of dynamo is actually acting in solar-like stars.
description: A poster for the Cool Stars 20.5 Virtual Conference
description: {"references": ["Skumanich (1972)", "De Rosa, Brun et al. (2012)", "Brun, Strugarek et al. (2017)"]}
A Telescope Search for Decaying Relic Axions
Creators: name: Grin, Daniel
name: Covone, Giovanni
name: Kneib, Jean-Paul
name: Kamionkowski, Marc
name: Blain, Andrew
name: Jullo, Eric
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: A search for optical line emission from the two-photon decay of relic axions was conducted in the galaxy clusters Abell 2667 and 2390, using spectra from the VIMOS (Visible Multi-Object Spectrograph) integral field unit at the Very Large Telescope. New upper limits to the two-photon coupling of the axion are derived, and are at least a factor of 3 more stringent than previous upper limits in this mass window. The improvement follows from larger collecting area, integration time, and spatial resolution, as well as from improvements in signal to noise and sky subtraction made possible by strong-lensing mass models of these clusters. The new limits either require that the two-photon coupling of the axion be extremely weak or that the axion mass window between 4.5 eV and 7.7 eV be closed. Implications for sterile-neutrino dark matter are discussed briefly also.
description: 14 pages, 10 figures, replaced with version published in Phys. Rev. D
Chandra LETGS spectroscopy of the Quasar MR2251-178 and its warm absorber
Creators: name: Ramírez, J. M.
name: Komossa, S.
name: Burwitz, V.
name: Mathur, S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present an analysis of our Chandra Low Energy Transmission Grating Spectrometer (LETGS) observation of the quasar MR2251-178. The warm absorber of MR2251-178 is well described by a hydrogen column density, N_H~2x10^21 cm^-2, and an ionization parameter log(xi)~0.6. We find in the spectrum weak evidence for narrow absorption lines from Carbon and Nitrogen which indicate that the ionized material is in outflow. We note changes (in time) of the absorption structure in the band (0.6-1) keV (around the UTAs plus the OVII and OVIII K-edges) at different periods of the observation. We measure a (0.1-2) keV flux of 2.58x10^-11 ergs cm^-2 s^-1. This flux implies that the nuclear source of MR2251-178 is in a relatively low state. No significant variability is seen in the light curve. We do not find evidence for an extra cold material in the line of sight, and set an upper limit of N_H~1.2x10^20 cm^-2. The X-ray spectrum does not appear to show evidence for dusty material, though an upper limit in the neutral carbon and oxygen column densities can only be set to N_CI~2x10^19 cm^-2 and N_OI~9x10^19 cm^-2, respectively.
description: 42 pages, 12 figures, Accepted in Apj. Typo in abstract (ver2): "We do not find evidence for an extra..."
On massive spin 2 interactions
Creators: name: Zinoviev, Yu. M.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this paper we use a constructive approach based on gauge invariant description of massive high spin particles for investigation of possible interactions of massive spin 2 particle. We work with general case of massive spin 2 particle living in constant curvature $(A)dS_d$ background, which allows us carefully consider all flat space, massless or partially massless limits. In the linear approximation (cubic terms with no more than two derivatives in the Lagrangians and linear terms with no more than one derivative in gauge transformations) we investigate possible self-interaction, interaction with matter (i.e. spin 0, 1 and 1/2 particles) and interaction with gravity.
description: 26 pages, LaTeX 2e, some comments and new references added
Εκτίμηση των δεικτών υγείας και παραγωγικής ικανότητας σε χοιροτροφικές εκμεταλλεύσεις της Β.Ελλάδος:
Creators: name: Μαλλιώρης, Γεράσιμος Παναγιώτη
Publisher: name: Aristotle University of Thessaloniki
Year: 2014
Subjects: Χοιροτροφικές εκμεταλλεύσεις
Δείκτες υγείας
Δείκτες παραγωγικής ικανότητας
Pig farms
Health indicators
Productive ability indicators

description: Ο στόχος της παρούσας διατριβής περιέλαβε τη μελέτη και την καταγραφή των δεικτών υγείας και αναπαραγωγικής ικανότητας στις εντατικές χοιροτροφικές εκμεταλλεύσεις της Βόρειας Ελλάδας. Κατά τη διάρκεια της συλλογής και της στατιστικής ανάλυσης των δεδομένων σημαντικά αποτελέσματα εμφανίστηκαν. Πολλές μεταβλητές, που έχουν επιπτώσεις στην υγεία και στην παραγωγή των εκτρεφόμενων χοίρων, εξετάστηκαν σε συνάρτηση, κυρίως με αυτές που περιλαμβάνουν την εφαρμογή μέτρων βιοασφάλειας, την κτηνιατρική και ζωοτεχνική διαχείριση, και των συνθηκών διαβίωσης. Υπήρξε θετικός συσχετισμός μεταξύ του υψηλού επιπέδου βιοασφάλειας και της συχνότητας επίβλεψης, σε σχέση με την υγεία των εκτρεφόμενων ζώων. Ακολούθως διαπιστώθηκε ότι υπάρχει αρνητική συσχέτιση μεταξύ της επίβλεψης από τους ιδιοκτήτες και του μεγέθους της εκμετάλλευσης. Η κτηνιατρική επίβλεψη ήταν περιορισμένη, στην πλειοψηφία των εκτροφών. Παρόμοια συμπεράσματα προέκυψαν και σε σχέση με την επίβλεψη από ζωοτέχνη. Διαπιστώθηκε ότι σε σημαντικό ποσοστό οι εγκαταστάσεις των εκμεταλλεύσεων κατασκευάστηκαν και εξοπλίστηκαν πριν από πολλά χρόνια. Ένας άλλος στόχος της μελέτης ήταν να εξεταστούν οι συνθήκες και η διαχείριση των ζώων αναπαραγωγής. Τέλος ιδιαίτερα, οι αναπαραγωγικές αποδόσεις στην Ελληνική εντατική χοιροτροφία υπολείπονται των διεθνών στόχων αναπαραγωγής όπως αυτές καταγράφονται στις σύγχρονες χοιροτροφικές εκμεταλλεύσεις.
description: The aim of the present thesis involved the study and recording of the reproduction and health indicators in intensive swine farming plants of Northern Greece. During data collection and their statistical analysis, significant results came up. Many variables which affect the health and reproduction of the swine’s were examined in correlation with mainly those including the application of biosecurity measures, the veterinary and animal husbandry service, together with the living conditions. There was a positive correlation between the high level of biosecurity and the frequency of supervising, concerning the health of the reared animals. Additionally, it was evident that there was a negative correlation between the supervising on the part of the owners and the size of the units. Veterinary supervision was limited in the majority of the plants. Similar conclusions came about in relation to supervision by an expert in animal husbandry. It was concluded that to a great extend the installations of the plants in reference were constructed and equipped many years ago. Another aim of the study was to examine the conditions and the management of the breeding animals. Finally the reproductive outcome concerning the Greek swine breeding are generally behind the international breeding goals as they are met in modern pig farms.
A vulnerability-stress model for the course of schizophrenia ?
Creators: name: Erickson, David Harry
Publisher: name: University of British Columbia
Year: 2009

description: Despite a prevailing paradigm that emphasizes an interaction of vulnerability and stress to account for the etiology of schizophrenia, diathesis—stress models of subsequent course and outcome of this disorder are rare. Even the simpler stress— process model, where the influence of stressors is mediated by supportive social relationships, has received little attention in studies of the course of schizophrenia. The objective of this study was to assess the following components of a diathesis—stress model as they predict the five-year outcome of first-episode schizophrenia: (1) stressful life events; (2) supportive social relationships; (3) brain lateral ventricle size; and (4) smooth pursuit eye movements. As part of the Greater Vancouver M.A.P. Project, we recruited first-episode DSM-III schizophrenia and affective psychosis patients. At intake to the study, their social relationships, smooth pursuit eye movement function, and brain ventricle size were assessed. Life events in the previous year were measured at intake; events over the following 18 months were assessed in two later interviews. Five years later we assessed outcome, using a global rating of social and occupational functioning. Descriptive results showed substantial variability within the schizophrenia group at intake and outcome. The trajectory of adaptive functioning over time was remarkably similar for the schizophrenic and affective psychosis groups. Of the four hypothesized predictors, only social relationships were associated (p=.O3) with five—year outcome. The number of life events was not associated with five—year outcome, nor was either of the biological risk factors. As a result, the predictor variables could not be combined in either a stress—process model or a vulnerability—stress model of the course of schizophrenia. That social relationship variables are associated with five-year outcome supports earlier findings regarding 18-month outcome, including the differing predictive roles for family and nonfamily relationships. The absence of hypothesized results for the life events data probably indicates that too much time had passed between outcome and the events as measured. Finally, that brain ventricle size and eye-movement dysfunction predict 18-month but not five—year outcome may indicate that impairment due to biological factors is expressed only in the early stages of schizophrenia.
The large-scale distribution of ionized metals in IllustrisTNG
Creators: name: Artale, M. Celeste
name: Haider, Markus
name: Montero-Dorta, Antonio D.
name: Vogelsberger, Mark
name: Martizzi, Davide
name: Torrey, Paul
name: Bird, Simeon
name: Hernquist, Lars
name: Marinacci, Federico
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We study the intrinsic large-scale distribution and evolution of seven ionized metals in the IllustrisTNG magneto-hydrodynamical cosmological simulation. We focus on the fractions of C\,\textsc{ii}, C\,\textsc{iv}, Mg\,\textsc{ii}, N\,\textsc{v}, Ne\,\textsc{viii}, O\,\textsc{vi}, and Si\,\textsc{iv} in different cosmic web structures (filaments, haloes, and voids) and gas phases (warm-hot intergalactic medium WHIM, hot, diffuse, and condensed gas) from $z=6$ to $z=0$. Our analysis provides a new perspective to the study of the distribution and evolution of baryons across cosmic time while offering new hints in the context of the well-known missing baryons problem. The cosmic web components are here identified using the local comoving dark matter density, which provides a simple but effective way of mapping baryons on large scales. Our results show that C\,\textsc{ii} and Mg\,\textsc{ii} are mostly located in condensed gas inside haloes in high-density and low-temperature star-forming regions ($ρ_{\rm gas}/\barρ_{\rm bar}\gtrsim10^3$, and ${\rm T}\lesssim10^{5}$~K). C\,\textsc{iv} and Si\,\textsc{iv} present similar evolution of their mass fractions in haloes and filaments across cosmic time. In particular, their mass budgets in haloes in condensed phase ($ρ_{\rm gas}/\barρ_{\rm bar}\gtrsim10^3$, and ${\rm T}\lesssim10^{5}$~K) are driven by gas cooling and star formation with a peak at $z\sim2$. Finally, our results confirm that O\,\textsc{vi}, Ne\,\textsc{viii}, and N\,\textsc{v} are good tracers of warm/hot and low-density gas at low redshift ($ρ_{\rm gas}/\barρ_{\rm bar}\lesssim10^3$, and ${\rm T}\gtrsim10^{5}$~K), regions that are likely to contain most of the missing baryons in the local Universe.
description: 15 pages, 9 figures. Submitted to MNRAS
Amplitude Modulation of Short Timescale Variability
Creators: name: Biddle, Lauren
name: Llama, Joe
name: Cameron, Andrew
name: Prato, Lisa
name: Jardine, Moira
name: Johns-Krull, Chris
Publisher: name: Zenodo
Year: 2021
Subjects: Young stars

description: Variability of Classical T Tauri Systems occurs over a range of timescales. A common source of this variability is caused by accretion shocks, which can hamper the detectability of young planets within these systems, further motivating the characterization of accretion signatures. We present analysis of small-amplitude photometric variability in the K2 lightcurve of CI Tau occurring on timescales of ≲1 d. Our findings reveal that the amplitude of this stochastic variability exhibits the same periodic signatures as detected in the large-amplitude variability, indicating that the physical mechanism modulating these brightness features is the same.
Maslov's complex germ and the Weyl--Moyal algebra in quantum mechanics and in quantum field theory
Creators: name: Stoyanovsky, A. V.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mathematical Physics (math-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The paper is a survey of some author's results related with the Maslov--Shvedov method of complex germ and with quantum field theory. The main idea is that many results of the method of complex germ and of perturbative quantum field theory can be made more simple and natural if instead of the algebra of (pseudo)differential operators one uses the Weyl algebra (operators with Weyl symbols) with the Moyal *-product. Section 1, devoted to quantum mechanics, contains a closed mathematical description of the Maslov--Shvedov method in the theory of Schrodinger equation, including the method of canonical operator. In particular, it contains a new simple definition of the Maslov index modulo 4. Section 2, devoted to quantum field theory, contains a logically self-consistent exposition of the main results of perturbative quantum field theory not using the subtraction of infinities from the quantum Hamiltonian of free field and normal ordering of operators. It also contains a result (dynamical evolution in quantum field theory in quasiclassical approximation) close to the Maslov--Shvedov quantum field theory complex germ.
description: 36 pages
Fellinger & Co
Creators: name: [s.n.]
Publisher: name: [s.n.]
Year: 1834

description: Ort: Neapel
description: Verzeichnung=Description=Inventaire 05.07.2020 Automatisiert nach HAN-Import
description: Verzeichnung=Description=Inventaire ISAD(G) / HAN Katalogisierungsregeln für Archivbestände Detailliert
The Effects of Starspots on Spectroscopic Mass Estimates of Young Stars
Creators: name: Flores, Christian
name: Connelley, Michael S.
name: Reipurth, Bo
name: Duchene, Gaspard
Publisher: name: Zenodo
Year: 2021
Subjects: Young stars

description: Magnetic fields and mass accretion processes create cold and hot spots on the surface of young stars, which affect the global temperatures measured on the sources. Previous studies have reported this problem on individual stars, but none has performed a large-scale study on this subject. We present an iSHELL high-resolution K-band spectroscopic survey of 42 young stars in Taurus-Aurigae and Ophiuchus star-forming regions. We use a magnetic radiative transfer code to measure the infrared temperature of the stars and their magnetic field strengths. We combine our infrared observations with optical measurements and find significant temperature differences between optical and IR values. The measured temperature differences increase with stellar temperature but also with magnetic field strength. We suggest that thermal inhomogeneities on the surface of the young stars (i.e., starspots) produce the observed temperature differences. To further understand the effects of the spots, we analyze a sub-sample of 25 stars that have dynamical masses measured with ALMA. We then use magnetic evolutionary models to compute stellar masses from optical and IR temperatures and compare them to the ALMA-derived masses. In the range of stellar masses analyzed (0.1-1.3 $\rm M_\odot$), neither IR nor optical temperature perfectly reproduces the stellar dynamical masses. However, on average, the IR temperatures provide more precise and accurate stellar masses than optical values
D-Brane Amplitudes in Topological String on Conifold
Creators: name: Okuyama, Kazumi
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the relation between two kinds of topological amplitudes of non-compact D-branes on conifold. In the A-model, D-branes are represented by fermion operators in the melting crystal picture and the amplitudes are given by the quantum dilogarithm. In the mirror B-model, D-branes correspond to the determinant operator det(x-M) in the Chern-Simons matrix model and the amplitudes are given by the Stieltjes-Wigert polynomial. We show that these two amplitudes are related by a certain integral transformation. We argue that this transformation represents the deformation of closed string background due to the presence of D-branes.
description: 13 pages; v2:references added
Forcart-Vischer, M., Witwe
Creators: name: [s.n.]
Publisher: name: [s.n.]
Year: 1834

description: Ort: Basel
description: Verzeichnung=Description=Inventaire 05.07.2020 Automatisiert nach HAN-Import
description: Verzeichnung=Description=Inventaire ISAD(G) / HAN Katalogisierungsregeln für Archivbestände Detailliert
Volunteer contributions to Wikipedia increased during COVID-19 mobility restrictions
Creators: name: Ruprechter, Thorsten
name: Ribeiro, Manoel Horta
name: Santos, Tiago
name: Lemmerich, Florian
name: Strohmaier, Markus
name: West, Robert
name: Helic, Denis
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computers and Society (cs.CY)
subject: FOS: Computer and information sciences

description: Wikipedia, the largest encyclopedia ever created, is a global initiative driven by volunteer contributions. When the COVID-19 pandemic broke out and mobility restrictions ensued across the globe, it was unclear whether Wikipedia volunteers would become less active in the face of the pandemic, or whether they would rise to meet the increased demand for high-quality information despite the added stress inflicted by this crisis. Analyzing 223 million edits contributed from 2018 to 2020 across twelve Wikipedia language editions, we find that Wikipedia's global volunteer community responded remarkably to the pandemic, substantially increasing both productivity and the number of newcomers who joined the community. For example, contributions to the English Wikipedia increased by over 20% compared to the expectation derived from pre-pandemic data. Our work sheds light on the response of a global volunteer population to the COVID-19 crisis, providing valuable insights into the behavior of critical online communities under stress.
Radiation pressure driven vibrational modes in ultra-high-Q silica microspheres
Creators: name: Ma, R.
name: Schliesser, A.
name: Del'Haye, P.
name: Dabirian, A.
name: Kippenberg, T. J.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Optics (physics.optics)
subject: Accelerator Physics (physics.acc-ph)
subject: FOS: Physical sciences

description: Quantitative measurements of the vibrational eigenmodes in ultra-high-Q silica microspheres are reported. The modes are efficiently excited via radiation-pressure induced dynamical back-action of light confined in the optical whispering-gallery modes of the microspheres (i.e. via the parametric oscillation instability). Two families of modes are studied and their frequency dependence on sphere size investigated. The measured frequencies are in good agreement both with Lamb's theory and numerical finite element simulation and are found to be proportional to the sphere's inverse diameter.
PROTECTIONISM AS A MEANS OF PROTECTING NATIONAL PRODUCERS: OPPORTUNITIES AND RISKS
Creators: name: Mavlanov, Anvarbek
Publisher: name: Zenodo
Year: 2025

description: This article analyzes the impact of protectionism policies on the national economy. The study examines the results of protectionist measures in the case of Uzbekistan, the United States, and China, as well as global protectionism trends based on data from the World Trade Organization (WTO). While protectionism offers opportunities to support national producers, create jobs, and diversify industries, it can also lead to problems such as price increases, technological backwardness, and the risk of international trade wars in the long term. Uzbekistan’s experience shows that balancing protectionism and free market principles is important. Based on the results of the study, proposals are put forward to introduce targeted protectionist measures, stimulate innovation, and expand international cooperation.
Hard X-ray emission of the microquasar GRO J1655-40 during the rise of its 2005 outburst
Creators: name: Joinet, A.
name: Kalemci, E.
name: Senziani, F.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the analysis of the high energy emission of the Galactic black hole GRO J1655-40 at the beginning of its 2005 outburst. The data from 458 ks of INTEGRAL observations, spread over 4 weeks, are analyzed, along with the existing simultaneous RXTE and Swift data. The high energy data allow us to detect the presence of a high energy cut-off and to study its evolution during the outburst rise. This high energy feature is generally related to thermal mechanisms in the framework of Comptonization models from which we can estimate the plasma parameters. We found an electron temperature of about 30-40 keV and an optical depth around 1.8-2.1. The high energy cut-off decreased along with the radio flux, and disappeared as the jet turned off.
description: 24 pages, 5 figures, accepted for publication in the Astrophsical Journal
High-energy particles in the wind nebula of pulsar B1509-58 as seen by INTEGRAL
Creators: name: Forot, M.
name: Hermsen, W.
name: Renaud, M.
name: Laurent, P.
name: Grenier, I.
name: Goret, P.
name: Khelifi, B.
name: Kuiper, L.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present observations with the INTEGRAL/IBIS telescope of the wind nebula powered by the young pulsar B1509-58 and we discuss the spatial and spectral properties of the unpulsed emission in the 20-200 keV energy band. The source extension and orientation along the northwest-southeast axis corresponds to the jet emission seen at keV and TeV energies. The hard X-ray spectrum is consistent with the earlier Beppo-SAX measurements. It follows a power law with a photon index alpha = -2.12 pm 0.05 up to 160 keV. A possible break at this energy is found at the 2.9 sigma confidence level. The 0.1-100 keV data are consistent with synchrotron aging of pairs in the jet and yield a magnetic field strength of 22-33 muG for a bulk velocity of 0.3-0.5c. The synchrotron cut-off energy thus corresponds to a maximum electron energy of 400-730 TeV.
description: 4 pages, 6 figures, accepted for publication in Apj
Guebhard, Charles
Creators: name: [s.n.]
Publisher: name: [s.n.]
Year: 1834

description: Ort: Anet / Ins BE
description: Verzeichnung=Description=Inventaire 05.07.2020 Automatisiert nach HAN-Import
description: Verzeichnung=Description=Inventaire ISAD(G) / HAN Katalogisierungsregeln für Archivbestände Detailliert
MPEC 2024-T136 : 2024 SW13
Creators: name: Minor Planet Center Staff
Publisher: name: The Minor Planet Center
Year: 2024
Subjects: subject: Small Solar System bodies
valueUri: http://astrothesaurus.org/uat/1469
subject: 2024 SW13

description: The Minor Planet Electronic Circulars contain information on unusual minor planets, routine data on comets and natural satellites, and occasional editorial announcements.  They are published on behalf of Division F of the International Astronomical Union by the Minor Planet Center, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Worst-Case Execution Time Calculation for Query-Based Monitors by Witness Generation
Creators: name: Búr, Márton
name: Marussy, Kristóf
name: Meyer, Brett H.
name: Varró, Dániel
Publisher: name: arXiv
Year: 2021
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences
subject: C.3.3

description: Runtime monitoring plays a key role in the assurance of modern intelligent cyber-physical systems, which are frequently data-intensive and safety-critical. While graph queries can serve as an expressive yet formally precise specification language to capture the safety properties of interest, there are no timeliness guarantees for such auto-generated runtime monitoring programs, which prevents their use in a real-time setting. While worst-case execution time (WCET) bounds derived by existing static WCET estimation techniques are safe, they may not be tight as they are unable to exploit domain-specific (semantic) information about the input models. This paper presents a semantic-aware WCET analysis method for data-driven monitoring programs derived from graph queries. The method incorporates results obtained from low-level timing analysis into the objective function of a modern graph solver. This allows the systematic generation of input graph models up to a specified size (referred to as witness models) for which the monitor is expected to take the most time to complete. Hence the estimated execution time of the monitors on these graphs can be considered as safe and tight WCET. Additionally, we perform a set of experiments with query-based programs running on a real-time platform over a set of generated models to investigate the relationship between execution times and their estimates, and compare WCET estimates produced by our approach with results from two well-known timing analyzers, aiT and OTAWA.
description: 36 pages, 11 figures, submitted to ACM Transactions on Embedded Computing Systems (accepted version)
An Antisymmetric Berry Frictional Force At Equilibrium in the Presence of Spin-Orbit Coupling
Creators: name: Teh, Hung-Hsuan
name: Dou, Wenjie
name: Subotnik, Joseph E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We analytically calculate the electronic friction tensor for a molecule near a metal surface in the case that the electronic Hamiltonian is complex-valued, e.g. the case that there is spin-orbit coupling and/or an external magnetic field. In such a case, even at equilibrium, we show that the friction tensor is not symmetric. Instead, the tensor is the real-valued sum of one positive definite tensor (corresponding to dissipation) plus one antisymmetric tensor (corresponding to a Berry pseudomagnetic force). Moreover, we find that this Berry force can be much larger than the dissipational force, suggesting the possibility of strongly spin-polarized chemicurrents or strongly spin-dependent rate constants for systems with spin-orbit coupling.
description: 6 pages, 2 figures (main text); 15 pages, 15 figures (supplemental material)
Spectral and Fourier analyses of X-ray QPO in accreting black holes
Creators: name: Sobolewska, M. A.
name: Zycki, P. T.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study energy dependencies of quasi-periodic oscillations from a number of black hole X-ray binaries. The selected sources were observed by RXTE at time periods close to state transitions and showed QPO in the 1-10 Hz range. We have constructed QPO root-mean-square energy spectra, which provide information about underlying physical processes leading to QPO generation. These spectra show an interesting anti-correlation with the time averaged spectra. The QPO r.m.s. spectra are harder than the time averaged spectra when the latter are soft, while they are softer than the time averaged spectra when the latter are hard. We then discuss these observational results in the context of simple spectral variability models. Hard QPO spectra can be produced by quasi-periodic modulations of the heating rate of the Comptonizing plasma, while soft QPO spectra result from modulations of the cooling rate by soft photons.
description: MNRAS, accepted, 10 pages. Paper shortened, discussion of Fourier frequency resolved spectra removed. Concentrates on energy spectra of QPO, no changes to results and conclusions in this part
Favier, Gervais, Voinier
Creators: name: [s.n.]
Publisher: name: [s.n.]
Year: 1834

description: Ort: Nancy
description: Verzeichnung=Description=Inventaire 05.07.2020 Automatisiert nach HAN-Import
description: Verzeichnung=Description=Inventaire ISAD(G) / HAN Katalogisierungsregeln für Archivbestände Detailliert
Rotational evolution of young stars: IC 348 and NGC 2362
Creators: name: Landin, Natália Rezende
name: Chaves, Jéssica Kerollayne Lemos
name: Souza, Thaís Suelen Marques
name: Mendes, Luiz Themystokliz Sanctos
name: Vaz, Luiz Paulo Ribeiro
name: Alencar, Silvia Helena Paixão
Publisher: name: Zenodo
Year: 2021
Subjects: Young stars
Rotation
Pre-main sequence
Disk-locking
Stellar evolution

description: Evolution of young stars' rotation is investigated by using evolutionary tracks considering conservation of angular momentum and simulations of disk-locking. By assuming that the disk-locking mechanism prevents the expected spin up in the pre-main sequence, we used evolutionary models and observational data to constraint disk lifetimes and locking periods of low-mass stars in the young clusters IC 348 and NGC 2362. We aim at understanding the rotational period distributions of these clusters' stars, which are known to be bimodal and dichotomic. The evolution is supposed to occur conserving angular momentum for fast rotators and conserving angular velocity before spinning up to the ZAMS for moderate rotators.
 We generated sets of evolutionary tracks and estimated a mass and an age for all stars. We found a mean age of 2.5Myr for IC 348 and 3.3Myr for NGC 2362. Most of stellar masses were found to be in the ranges of 0.1-0.8M\({\odot}\) for both clusters. In order to investigate the disk-locking effects in these stars, two hypotheses were tested and compared with observational disk indicators available in the literature. In hypothesis 1, we considered that peaks at longer periods are formed by stars with angular velocities locked to a circumstelar disk. Hypothesis 2 considers that rotation period distributions of both clusters were similar to that of Orion Nebula Cluster (ONC) when they had, on average, the same age as ONC (\(\gtrsim\)1Myr). This scenario implies that some of stars of IC 348 and NGC 2362 were kept locked in their disks during their first million years, and, after that, they evolved conserving their angular momentum. We, then, simulated period distributions for IC 348 and NGC 2362 at about 1Myr and realized that they were similar to that of ONC. Our results favors hypothesis 2 and indicate that the disk-locking mechanism seems to operate in young stars with a locking period of 8 days during a mean disk lifetime of about 1-1.5Myr.
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Charge ordering and coexistence of charge fluctuations in quasi-two-dimensional organic conductors $θ$-(BEDT-TTF)$_2X$
Creators: name: Udagawa, Masafumi
name: Motome, Yukitoshi
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We present a scenario for the peculiar coexistence of charge fluctuations observed in quasi-2D 1/4-filled organic conductors $θ$-(BEDT-TTF)$_2X$ in the quantum critical regime where the charge ordering is suppressed down to zero temperature. The scenario is explored in the extended Hubbard model including electron-phonon couplings on an anisotropic triangular lattice. We find that the coexisting fluctuations emerge from two different instabilities, the ``Wigner crystallization on lattice'' driven by the off-site Coulomb repulsion and the charge-density-wave formation due to the nesting of the Fermi surface, not from phase competition or real-space inhomogeneity. This mechanism explains the contrastive temperature dependence of two fluctuations in experiments.
description: 4 pages, 3 figures
Galli & Brambilla
Creators: name: [s.n.]
Publisher: name: [s.n.]
Year: 1834

description: Ort: Mailand
description: Verzeichnung=Description=Inventaire 05.07.2020 Automatisiert nach HAN-Import
description: Verzeichnung=Description=Inventaire ISAD(G) / HAN Katalogisierungsregeln für Archivbestände Detailliert
Inflation, phase transitions and the cosmological constant
Creators: name: Bertolami, Orfeu
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Cosmological phase transitions are thought to have taken place at the early Universe imprinting their properties on the observable Universe. There is strong evidence that, through the dynamics of a scalar field that lead a second order phase transition, inflation shaped the Universe accounting for the most conspicuous features of the observed Universe. It is argued that inflation has also striking implications for the vacuum energy. Considerations for subsequent second order phase transitions are also discussed.
description: 9 pages. Version to match to one to be published in General Relativity and Gravitation
Fioretti, Gaspare
Creators: name: [s.n.]
Publisher: name: [s.n.]
Year: 1834

description: Ort: Brescia
description: Verzeichnung=Description=Inventaire 05.07.2020 Automatisiert nach HAN-Import
description: Verzeichnung=Description=Inventaire ISAD(G) / HAN Katalogisierungsregeln für Archivbestände Detailliert
Astrophysical Constraints on the Symmetry Energy and the Neutron Skin of $^{208}$Pb with Minimal Modeling Assumptions
Creators: name: Essick, Reed
name: Tews, Ingo
name: Landry, Philippe
name: Schwenk, Achim
Publisher: name: arXiv
Year: 2021
Subjects: subject: Nuclear Theory (nucl-th)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The symmetry energy and its density dependence are crucial inputs for many nuclear physics and astrophysics applications, as they determine properties ranging from the neutron-skin thickness of nuclei to the crust thickness and the radius of neutron stars. Recently, PREX-II reported a value of $0.283 \pm 0.071$ fm for the neutron-skin thickness of $^{208}$Pb, implying a slope parameter $L = 106 \pm 37$ MeV, larger than most ranges obtained from microscopic calculations and other nuclear experiments. We use a nonparametric equation of state representation based on Gaussian processes to constrain the symmetry energy $S_0$, $L$, and $R_\mathrm{skin}^{^{208}\mathrm{Pb}}$ directly from observations of neutron stars with minimal modeling assumptions. The resulting astrophysical constraints from heavy pulsar masses, LIGO/Virgo, and NICER clearly favor smaller values of the neutron skin and $L$, as well as negative symmetry incompressibilities. Combining astrophysical data with PREX-II and chiral effective field theory constraints yields $S_0 = 33.0^{+2.0}_{-1.8}$ MeV, $L=53^{+14}_{-15}$ MeV, and $R_\mathrm{skin}^{^{208}\mathrm{Pb}}=0.17^{+0.04}_{-0.04}$ fm.
description: 11 pages, 6 figures, 2 tables
Gavazzi & Quinterio
Creators: name: [s.n.]
Publisher: name: [s.n.]
Year: 1834

description: Ort: Mailand
description: Verzeichnung=Description=Inventaire 05.07.2020 Automatisiert nach HAN-Import
description: Verzeichnung=Description=Inventaire ISAD(G) / HAN Katalogisierungsregeln für Archivbestände Detailliert
Recovery of TESS Stellar Rotation Periods with Convolutional Neural Networks
Creators: name: Claytor, Zachary R
name: van Saders, Jennifer
Publisher: name: Zenodo
Year: 2021

description: A poster for the Cool Stars 20.5 virtual conference. Abstract: Complete pictures of stellar structure, magnetism, activity, and evolution are not possible without understanding rotation. While the Kepler mission revolutionized stellar astrophysics with tens of thousands of rotation period estimates, TESS is poised to increase the number of detected periods by an order of magnitude. However, systematics of the TESS mission have complicated period searches. While there are several efforts to solve this problem by removing systematics, standard methods of data reduction have shown little success. We present a method to predict rotation periods from TESS full-frame image light curves using a convolutional neural network. This method relies on a set of simulated light curves convolved with TESS galaxy light curves to emulate the instrumental noise observed in stellar signals. The simulations include a full treatment of latitudinal differential rotation, star spot evolution, and activity level to make the light curves as realistic as possible. Our approach allows the network to learn the difference between rotation signals and TESS systematics. With these tools, we can reliably estimate periods as well as a credence metric to determine the regions of parameter space the network predictions are most reliable. Using the most credible half of the test data, we predict 60% of simulation periods to within 10% accuracy, on par with some of the methods used to estimate periods from Kepler data.
Flersheim, Salomon, & Co
Creators: name: [s.n.]
Publisher: name: [s.n.]
Year: 1834

description: Ort: Frankfurt a. M.
description: Verzeichnung=Description=Inventaire 05.07.2020 Automatisiert nach HAN-Import
description: Verzeichnung=Description=Inventaire ISAD(G) / HAN Katalogisierungsregeln für Archivbestände Detailliert
Summary: Acoustic Detection of EHE Neutrinos
Creators: name: Vandenbroucke, Justin
Publisher: name: arXiv
Year: 2006
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Neutrino astronomy was initiated primarily to search for TeV to PeV neutrinos from Active Galactic Nuclei, and the optical Cherenkov technique is well suited for this energy range. Interest has grown recently in detecting EeV neutrinos, particularly the ``cosmogenic'' neutrinos produced during propagation of ultra-high-energy cosmic rays (UHECR) through the microwave background radiation. These neutrinos could be a powerful tool both to resolve the mystery of the UHECR sources and to test fundamental physics at the $\sim$100 TeV scale. The optical technique is not cost effective at these energies and newer techniques such as radio and acoustic detection are necessary. Accelerator experiments have confirmed the production of both types of signals from high-energy showers in various media, and quantitative measurements have confirmed theoretical descriptions of the signal strength, frequency content and pulse shape. While radio experiments have set the strongest limits so far, the acoustic method could contribute with an entirely independent signal production and detection mechanism and may be more effective at the highest energies. Efforts are underway to develop the acoustic method in various media around the world, with arrays operating in ocean water at the Bahamas, the UK, and the Mediterranean Sea; detectors prepared for deployment in the South Pole ice in the next year; and ideas for future acoustic detectors in salt domes and on Antarctica's Ross Ice Shelf. Regardless of which method is individually most sensitive, the best configuration may be to co-deploy arrays to combine the techniques and seek coincident detection of individual neutrino events.
description: 6 pages, 3 figures, to appear in the Proceedings of the 2nd TeV Particle Astrophysics Conference, Madison, WI, August 28-31, 2006
N=31 is not IIB
Creators: name: Gran, U.
name: Gutowski, J.
name: Papadopoulos, G.
name: Roest, D.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We adapt the spinorial geometry method to investigate supergravity backgrounds with near maximal number of supersymmetries. We then apply the formalism to show that the IIB supergravity backgrounds with 31 supersymmetries preserve an additional supersymmetry and so they are maximally supersymmetric. This rules out the existence of IIB supergravity preons.
description: 7 pages
Favarger, C. F. L
Creators: name: [s.n.]
Publisher: name: [s.n.]
Year: 1834

description: Ort: St Thomas / New York
description: Verzeichnung=Description=Inventaire 05.07.2020 Automatisiert nach HAN-Import
description: Verzeichnung=Description=Inventaire ISAD(G) / HAN Katalogisierungsregeln für Archivbestände Detailliert
Follow the Lithium: The Correlation Between Li-bearing Molecules with Age, Mass, and Gravity in Brown Dwarfs
Creators: name: Gharib-Nezhad, Ehsan
name: Marley, Mark
name: Batalha, Natasha
name: Visscher, Channon
Publisher: name: Zenodo
Year: 2021
Subjects: Very low mass stars

description: Lithium is an important element for the understanding of ultracool dwarfs because it is lost to fusion at masses above 68 MJup. Hence, the presence or absence of atomic Li has served as an indicator of the nearby H-burning boundary at about 75 MJup between brown-dwarfs and very low-mass stars. Historically, the “Li test’’, a search for the presence and strength of the Li line at 670.8 nm, has been a marker if an object has a substellar mass with stellar-like spectral energy distribution (e.g., a late-type M dwarf). However, the Li test is not a reliable and straightforward probe to determine the mass and gravity of the ultracool object. In addition, for later T and Y type brown dwarfs, Li is no longer found as an atomic gas, but rather a molecular speciessuch as LiH, LiF, LiOH, and LiCl. Only recently have experimental molecular line lists become available for such species. In this study, we generated a full spectral absorption cross-section of each of these Li-bearing molecules from the most recent line-lists for 75-4000 K and 10−6-3000 bar. Then, thermochemical equilibrium atmospheric composition was performed to calculate the abundance of these molecules in this same temperature and pressure domain. Finally, we compute thermal emission spectra for a series of radiative-convective equilibrium modeling on cloudy and cloud-free brown dwarf atmospheres (with Teff=1000, 1500, 2000, 2400K) to understand where the presence or absence of atmospheric lithium-bearing species is most easily detected as a function of brown dwarf mass and age. After atomic Li, the best spectral signature was found to be LiF at 10.5-13 micron and LiCl at 15-18 micron. We predict that future missions such as James Webb Space telescopes could detect these LiF and LiCl spectral features. The detection of lithium compounds in cool objects would identify those with masses below the Lithium burning minimum mass, providing a new mass indicator for cool brown dwarfs.
description: Please find me at: Homepage: https://ehsangharibnezhad.github.io Twitter: https://twitter.com/exoEhsan
Convex Hypersurfaces in Hadamard Manifolds
Creators: name: Borisenko, Alexander A.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Differential Geometry (math.DG)
subject: FOS: Mathematics

description: We prove a theorem about an extremal property of Lobachevsky space among simply connected Riemannian manifolds of nonpositive curvature
EfficientLPS: Efficient LiDAR Panoptic Segmentation
Creators: name: Sirohi, Kshitij
name: Mohan, Rohit
name: Büscher, Daniel
name: Burgard, Wolfram
name: Valada, Abhinav
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Machine Learning (cs.LG)
subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Panoptic segmentation of point clouds is a crucial task that enables autonomous vehicles to comprehend their vicinity using their highly accurate and reliable LiDAR sensors. Existing top-down approaches tackle this problem by either combining independent task-specific networks or translating methods from the image domain ignoring the intricacies of LiDAR data and thus often resulting in sub-optimal performance. In this paper, we present the novel top-down Efficient LiDAR Panoptic Segmentation (EfficientLPS) architecture that addresses multiple challenges in segmenting LiDAR point clouds including distance-dependent sparsity, severe occlusions, large scale-variations, and re-projection errors. EfficientLPS comprises of a novel shared backbone that encodes with strengthened geometric transformation modeling capacity and aggregates semantically rich range-aware multi-scale features. It incorporates new scale-invariant semantic and instance segmentation heads along with the panoptic fusion module which is supervised by our proposed panoptic periphery loss function. Additionally, we formulate a regularized pseudo labeling framework to further improve the performance of EfficientLPS by training on unlabelled data. We benchmark our proposed model on two large-scale LiDAR datasets: nuScenes, for which we also provide ground truth annotations, and SemanticKITTI. Notably, EfficientLPS sets the new state-of-the-art on both these datasets.
description: Ranked #1 on SemanticKITTI and nuScenes panoptic segmentation benchmarks