cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
title: Ανάπτυξη λογισμικού δημιουργίας αριθμητικού πλέγματος και υπολογιστική μελέτη ροής και καύσης σε δίχρονο ναυτικό κινητήρα
titleType: AlternativeTitle
title: Software developement for grid generation and study on flow and combustion for a two stroke marine engine
Creators: name: Malikouti, Christina E.
Publisher: name: National Technological University of Athens
Year: 2013
Subjects: Υπολογιστική ρευστοδυναμική
Δίχρονοι ναυτικοί κινητήρες
Καύση
Λογισμικό κατασκευής αριθμητικού πλέγματος
Ναυτική μηχανολογία
Computational fluid dynamics
Two stroke marine engines
GMSH
KIVA-3
Combustion
Grid Generation Software

description: 71 σ.
description: Οι αέριοι ρύποι που εκπέμπουν οι ναυτικοί κινητήρες Diesel αποτελούν σημαντικούς παράγοντες για τη ρύπανση του περιβάλλοντος. Ο Διεθνής Ναυτιλιακός Οργανισμός (International Maritime Organization - IMO) και η Ευρωπαϊκή Ένωση έχουν θεσπίσει καινούργια μέτρα και περιορισμούς για τις εκπομπές αερίων ρύπων, ώστε η λειτουργία των ναυτικών κινητήρων να αποβεί φιλικότερη για το περιβάλλον και τον άνθρωπο, χωρίς ταυτόχρονα να επηρεάζεται η αξιοπιστία και η απόδοσή αυτών. Σήμερα, η Υπολογιστική Ρευστοδυναμική (CFD) αποτελεί ένα αξιόπιστο μέσο για τη μελέτη και βελτίωση της θερμορευστομηχανικής των ναυτικών κινητήρων. Στην παρούσα διπλωματική εργασία, μελετάται η ανάπτυξη αριθμητικού πλέγματος για την προσομοίωση του μεγάλου δίχρονου ναυτικού κινητήρα Diesel RT-flex96C της κατασκευάστριας εταιρείας Wärtsilä Switzerland, με διάμετρο και διαδρομή εμβόλου 0.96 m και 2.5 m, αντίστοιχα. Η μελέτη αυτή χωρίζεται σε δύο στάδια: (α) δημιουργία αριθμητικού πλέγματος για τη γεωμετρία του κινητήρα και (β) προσομοίωση της ροής και καύσης, για την περιοχή πλήρους φορτίου, με χρήση του κώδικα Υπολογιστικής Ρευστοδυναμικής KIVA-3. Αρχικά, η αποτύπωση της γεωμετρίας του θαλάμου καύσης του κινητήρα και η δημιουργία του αρχικού αριθμητικού πλέγματος πραγματοποιείται μέσω της ρουτίνας δημιουργίας πλέγματος του κώδικα KIVA-3 (ρουτίνα “k3prep”). Η ρουτίνα χαρακτηρίζεται από κάποια μειονεκτήματα, και χρήζει βελτιώσεων. Για τον λόγο αυτόν, αναπτύχθηκε στην παρούσα εργασία μια εναλλακτική μεθοδολογία δημιουργίας αριθμητικών πλεγμάτων, η οποία περιλαμβάνει τη σύζευξη: (α) της ρουτίνας “k3prep”, (β) του λογισμικού GMSH, και (γ) του λογισμικού Octave. Το λογισμικό που αναπτύχθηκε απέδωσε πληρέστερα τη γεωμετρία του κινητήρα RT-flex96C, και αποδείχτηκε εν γένει καταλληλότερο για αντίστοιχες εφαρμογές δημιουργίας πλέγματος σε εφαρμογές μεγάλων κινητήρων. Στην παρούσα εργασία, έγινε μελέτη ανεξαρτησίας πλέγματος και χρονικού βήματος, στο πλαίσιο της οποίας χρησιμοποιήθηκαν, ως μέτρο σύγκρισης, και πειραματικά αποτελέσματα. Ακολούθως, μελετήθηκε η λειτουργία του κινητήρα RT-flex96C στην περιοχή του πλήρους φορτίου, συγκεκριμένα: (α) μια περίπτωση αναφοράς, χαρακτηριζόμενη από συνεχές προφίλ έγχυσης, (β) περιπτώσεις λειτουργίας στην περιοχή του πλήρους φορτίου, χαρακτηριζόμενες από διαφορετικά επίπεδα εγκάρσιας συστροφής του αέρα (swirl), και (γ) δύο περιπτώσεις χαρακτηριζόμενες από προέγχυση και κύρια έγχυση. Η παρούσα εργασία δημιουργεί τη βάση για περαιτέρω υπολογιστική μελέτη και βελτιστοποίηση του παρόντος δίχρονου ναυτικού κινητήρα.
Synthetic spin orbit interaction for Majorana devices
Creators: name: Desjardins, M. M.
name: Contamin, L. C.
name: Delbecq, M. R.
name: Dartiailh, M. C
name: Bruhat, L. E.
name: Cubaynes, T.
name: Viennot, J. J.
name: Mallet, F.
name: Rohart, S.
name: Thiaville, A.
name: Cottet, A.
name: Kontos, T.
Publisher: name: arXiv
Year: 2019
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: The interplay of superconductivity with a non-trivial spin texture holds promises for the engineering of non-abelian Majorana quasi-particles. A wide class of systems expected to exhibit exotic correlations are based on nanoscale conductors with strong spin-orbit interaction, subject to a strong external magnetic field. The strength of the spin-orbit coupling is a crucial parameter for the topological protection of Majorana modes as it forbids other trivial excitations at low energy. The spin-orbit interaction is in principle intrinsic to a material. As a consequence, experimental efforts have been recently focused on semiconducting nano-conductors or spin-active atomic chains contacted to a superconductor. Alternatively, we show how both a spin-orbit and a Zeeman effect can be autonomously induced by using a magnetic texture coupled to any low dimensional conductor, here a carbon nanotube. Transport spectroscopy through superconducting contacts reveals oscillations of Andreev like states under a change of the magnetic texture. These oscillations are well accounted for by a scattering theory and are absent in a control device with no magnetic texture. A large synthetic spin-orbit energy of about 1.1 meV, larger than the intrinsic spin orbit energy in many other platforms, is directly derived from the number of oscillations. Furthermore, a robust zero energy state, the hallmark of devices hosting localized Majorana modes, emerges at zero magnetic field. Our findings synthetize all the features for the emergence of Majorana modes at zero magnetic field in a controlled, local and autonomous fashion. It could be used for advanced experiments, including microwave spectroscopy and braiding operations, which are at the heart of new schemes of topological quantum computation.
Analog gravity from Bose-Einstein condensates
Creators: name: Barcelo, Carlos
name: Liberati, Stefano
name: Visser, Matt
Publisher: name: arXiv
Year: 2000
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Condensed Matter (cond-mat)
subject: FOS: Physical sciences

description: We analyze prospects for the use of Bose-Einstein condensates as condensed-matter systems suitable for generating a generic ``effective metric'', and for mimicking kinematic aspects of general relativity. We extend the analysis due to Garay et al, [gr-qc/0002015, gr-qc/0005131]. Taking a long term view, we ask what the ultimate limits of such a system might be. To this end, we consider a very general version of the nonlinear Schrodinger equation (with a 3-tensor position-dependent mass and arbitrary nonlinearity). Such equations can be used for example in discussing Bose-Einstein condensates in heterogeneous and highly nonlinear systems. We demonstrate that at low momenta linearized excitations of the phase of the condensate wavefunction obey a (3+1)-dimensional d'Alembertian equation coupling to a (3+1)-dimensional Lorentzian-signature ``effective metric'' that is generic, and depends algebraically on the background field. Thus at low momenta this system serves as an analog for the curved spacetime of general relativity. In contrast at high momenta we demonstrate how to use the eikonal approximation to extract a well-controlled Bogoliubov-like dispersion relation, and (perhaps unexpectedly) recover non-relativistic Newtonian physics at high momenta. Bose-Einstein condensates appear to be an extremely promising analog system for probing kinematic aspects of general relativity.
description: revtex 4 (beta 4); 15 pages in single-column format
An autocovariance-based learning framework for high-dimensional functional time series
Creators: name: Chang, Jinyuan
name: Chen, Cheng
name: Qiao, Xinghao
name: Yao, Qiwei
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistics Theory (math.ST)
subject: Methodology (stat.ME)
subject: FOS: Mathematics
subject: FOS: Computer and information sciences

description: Many scientific and economic applications involve the statistical learning of high-dimensional functional time series, where the number of functional variables is comparable to, or even greater than, the number of serially dependent functional observations. In this paper, we model observed functional time series, which are subject to errors in the sense that each functional datum arises as the sum of two uncorrelated components, one dynamic and one white noise. Motivated from the fact that the autocovariance function of observed functional time series automatically filters out the noise term, we propose a three-step procedure by first performing autocovariance-based dimension reduction, then formulating a novel autocovariance-based block regularized minimum distance estimation framework to produce block sparse estimates, and based on which obtaining the final functional sparse estimates. We investigate theoretical properties of the proposed estimators, and illustrate the proposed estimation procedure via three sparse high-dimensional functional time series models. We demonstrate via both simulated and real datasets that our proposed estimators significantly outperform the competitors.
description: 36 pages, 1 figure
Dust emission from 3C radio galaxies and quasars: New ISO observations favour the unified scheme
Creators: name: Meisenheimer, K.
name: Haas, M.
name: Müller, S. A. H.
name: Chini, R.
name: Klaas, U.
name: Lemke, D.
Publisher: name: arXiv
Year: 2001
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In order to test the unified scheme for luminous radio galaxies and quasars we observed 10 galaxy/quasar pairs from the 3CR catalogue with ISOPHOT at infrared wavelengths between 5 and 180 micron. Each pair was selected such that both the 178 MHz luminosity and the redshift match as close as possible between the radio galaxy and the quasar in order to minimize effects of cosmic evolution. 13 of the 20 sources were detected in at least one waveband. 12 sources show clear evidence of a thermal bump at FIR wavelength, while in the remaining 7 sources the upper limits are still compatible with the presence of luminous dust emission. In agreement with the predictions of the unified scheme, the quasars and galaxies in our sample cannot be distinguished by their observed mid- and far-infrared properties. This is in contrast to the IRAS results which indicated that radio galaxies radiate significantly less mid- to far-infrared emission than quasars. However, the IRAS samples are dominated by low-redshift sources (z < 0.5), while our sample contains several of the most luminous radio galaxies at redshift z ~ 1. The latter have already been suspected to contain a hidden quasar for other reasons, e.g. an extended emission line region aligned with the radio axis. From the ratio between FIR luminosity emitted by dust and the radio power at 178 MHz, we conclude that the radio galaxy/quasar unification might be perfectly valid for the most luminous 3C sources at high redshift (z > 0.8). At lower redshifts (z < 0.5), however, some of the FRII radio galaxies contain active nuclei which emit less UV-optical continuum than the quasars of similar radio power. (abrigded)
description: 10 pages, 6 figures, Latex
Strohminger & Nichols (2014) replication & extension
Creators: name: Wong, Chung
name: Feldman, Gilad
Publisher: name: Open Science Framework
Year: 2022
Subjects: subject: Social and Behavioral Sciences
subject: judgment and decision making
subject: replication
subject: true self

description: Please see pre-registration folder for Qualtrics survey and very detailed pre-registration with simulated random dataset and analysis code attached.
On a class of canonical systems corresponding to matrix string equations: general-type and explicit fundamental solutions and Weyl--Titchmarsh theory
Creators: name: Sakhnovich, Alexander
Publisher: name: arXiv
Year: 2020
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: Mathematical Physics (math-ph)
subject: Dynamical Systems (math.DS)
subject: Functional Analysis (math.FA)
subject: Spectral Theory (math.SP)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 34A05, 34B20, 37J05, 45D05

description: An important representation of the general-type fundamental solutions of the canonical systems corresponding to matrix string equations is established using linear similarity of a certain class of Volterra operators to the squared integration. Explicit fundamental solutions of these canonical systems are also constructed via the GBDT version of Darboux transformation. Examples and applications to dynamical canonical systems are given. Explicit solutions of the dynamical canonical systems are constructed as well. Three appendices are dedicated to the Weyl--Titchmarsh theory for canonical systems, transformation of a subclass of canonical systems into matrix string equations (and of a smaller subclass of canonical systems into matrix Schrödinger equations), and a linear similarity problem for Volterra operators.
description: Some results and ideas from our papers arXiv:nlin/0402055, arXiv:2002.04975, and arXiv:2003.13024 have been used in this work. Several references are added in the second version as well as small complements in the text
Diffusion controlled initial recombination
Creators: name: Christen, T.
name: Buttiker, M.
Publisher: name: arXiv
Year: 1997
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: This work addresses nucleation rates in systems with strong initial recombination. Initial (or `geminate') recombination is a process where a dissociated structure (anion, vortex, kink etc.) recombines with its twin brother (cation, anti-vortex, anti-kink) generated in the same nucleation event. Initial recombination is important if there is an asymptotically vanishing interaction force instead of a generic saddle-type activation barrier. At low temperatures, initial recombination strongly dominates homogeneous recombination. In a first part, we discuss the effect in one-, two-, and three-dimensional diffusion controlled systems with spherical symmetry. Since there is no well-defined saddle, we introduce a threshold which is to some extent arbitrary but which is restricted by physically reasonable conditions. We show that the dependence of the nucleation rate on the specific choice of this threshold is strongest for one-dimensional systems and decreases in higher dimensions. We discuss also the influence of a weak driving force and show that the transport current is directly determined by the imbalance of the activation rate in the direction of the field and the rate against this direction. In a second part, we apply the results to the overdamped sine-Gordon system at equilibrium. It turns out that diffusive initial recombination is the essential mechanism which governs the equilibrium kink nucleation rate. We emphasize analogies between the single particle problem with initial recombination and the multi-dimensional kink-antikink nucleation problem.
description: LaTeX, 11 pages, 1 ps-figures Extended version
Variational Dynamic for Self-Supervised Exploration in Deep Reinforcement Learning
Creators: name: Bai, Chenjia
name: Liu, Peng
name: Liu, Kaiyu
name: Wang, Lingxiao
name: Zhao, Yingnan
name: Han, Lei
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (cs.LG)
subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: Efficient exploration remains a challenging problem in reinforcement learning, especially for tasks where extrinsic rewards from environments are sparse or even totally disregarded. Significant advances based on intrinsic motivation show promising results in simple environments but often get stuck in environments with multimodal and stochastic dynamics. In this work, we propose a variational dynamic model based on the conditional variational inference to model the multimodality and stochasticity. We consider the environmental state-action transition as a conditional generative process by generating the next-state prediction under the condition of the current state, action, and latent variable, which provides a better understanding of the dynamics and leads a better performance in exploration. We derive an upper bound of the negative log-likelihood of the environmental transition and use such an upper bound as the intrinsic reward for exploration, which allows the agent to learn skills by self-supervised exploration without observing extrinsic rewards. We evaluate the proposed method on several image-based simulation tasks and a real robotic manipulating task. Our method outperforms several state-of-the-art environment model-based exploration approaches.
description: IEEE Transactions on Neural Networks and Learning Systems (TNNLS) 2021
Pseudoglyptodon Engelmann 1987
Creators: name: Casali, Daniel M
name: Boscaini, Alberto
name: Gaudin, Timothy J
name: Perini, Fernando A
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Pilosa
Cyclopedidae
Pseudoglyptodon

description: Folivora minus Pseudoglyptodon
PP = 100, age = 37.98 Mya (33.43–43.47).
 The clade is composed of the living genus Bradypus and Eufolivora. It was consistently recovered in all analyses performed in this study, except in par_EW consensus, in which Pseudoglyptodon, Bradypus and Eufolivora were arranged in a polytomy.
The clade was supported by nine synapomorphies (two for both methods and seven exclusively for BI): a large basin for the modified orthodentine core; ovate cf1 cross-section (BI); anteroposteriorly ovate Mf1 crosssection (BI); anteroposteriorly ovate mf1 cross-section (B1); bilobate Mf2 and Mf3 cross-section (BI); bilobate mf2 cross-section (BI); ascending ramus of mandible not covering the posterior teeth in lateral view (BI); presence of posterior external opening of mandibular canal; and maximum length of nasal bones greater than, or equal to, twice the width of both nasals, but less than three times (BI).
description: Published as part of Casali, Daniel M, Boscaini, Alberto, Gaudin, Timothy J & Perini, Fernando A, 2022, Reassessing the phylogeny and divergence times of sloths (Mammalia: Pilosa: Folivora), exploring alternative morphological partitioning and dating models, pp. 1505-1551 in Zoological Journal of the Linnean Society 196 (4) on page 1520, DOI: 10.1093/zoolinnean/zlac041, http://zenodo.org/record/7381236
A back-linked Fabry-Perot interferometer for space-borne gravitational wave observations
Creators: name: Izumi, Kiwamu
name: Fujimoto, Masa-Katsu
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Direct observations of gravitational waves at frequencies below 10 Hz will play crucial roles for fully exploiting the potential of gravitational wave astronomy. One approach to pursue this direction is the utilization of laser interferometers equipped with the Fabry-Perot optical cavities in space. However, a number of challenges lie in this path practically. In particular, the implementation of precision control for the cavity lengths and the suppression of laser phase noises may prevent a practical detector design. To circumvent such difficulties, we propose a new interferometer topology, named the back-linked Fabry-Perot interferometer, where the precision length controls are not required and an offline subtraction scheme for laser phase noises is readily applicable. This article presents the principle idea and the associated sensitivity analyses. Despite additional noises, a strain sensitivity of $7\times 10^{-23}$ Hz$^{-1/2}$ may be attainable in the deci-Hertz band. Several technological developments and studies must be carried out to pave the way forward for the implementation.
Long-term woodland restoration on lowland farmland through passive rewilding
Creators: name: Broughton, Richard K.
name: Bullock, James M.
name: George, Charles
name: Hill, Ross A.
name: Hinsley, Shelley A.
name: Maziarz, Marta
name: Melin, Markus
name: Mountford, J. Owen
name: Sparks, Tim H.
name: Pywell, Richard F.
Publisher: name: Apollo - University of Cambridge Repository
Year: 2021
Subjects: subject: Research Article
subject: Ecology and environmental sciences
subject: Biology and life sciences
subject: Engineering and technology
subject: FOS: Engineering and technology
subject: People and places

description: Natural succession of vegetation on abandoned farmland provides opportunities for passive rewilding to re-establish native woodlands, but in Western Europe the patterns and outcomes of vegetation colonisation are poorly known. We combine time series of field surveys and remote sensing (lidar and photogrammetry) to study woodland development on two farmland fields in England over 24 and 59 years respectively: the New Wilderness (2.1 ha) abandoned in 1996, and the Old Wilderness (3.9 ha) abandoned in 1961, both adjacent to ancient woodland. Woody vegetation colonisation of the New Wilderness was rapid, with 86% vegetation cover averaging 2.9 m tall after 23 years post-abandonment. The Old Wilderness had 100% woody cover averaging 13.1 m tall after 53 years, with an overstorey tree-canopy (≥ 8 m tall) covering 91%. By this stage, the structural characteristics of the Old Wilderness were approaching those of neighbouring ancient woodlands. The woody species composition of both Wildernesses differed from ancient woodland, being dominated by animal-dispersed pedunculate oak Quercus robur and berry-bearing shrubs. Tree colonisation was spatially clustered, with wind-dispersed common ash Fraxinus excelsior mostly occurring near seed sources in adjacent woodland and hedgerows, and clusters of oaks probably resulting from acorn hoarding by birds and rodents. After 24 years the density of live trees in the New Wilderness was 132/ha (57% oak), with 390/ha (52% oak) in the Old Wilderness after 59 years; deadwood accounted for 8% of tree stems in the former and 14% in the latter. Passive rewilding of these ‘Wilderness’ sites shows that closed-canopy woodland readily re-established on abandoned farmland close to existing woodland, it was resilient to the presence of herbivores and variable weather, and approached the height structure of older woods within approximately 50 years. This study provides valuable long-term reference data in temperate Europe, helping to inform predictions of the potential outcomes of widespread abandonment of agricultural land in this region.
Explaining Deviations from the Scaling Relationship of the Large Frequency Separation
Creators: name: Ong, Joel
name: Basu, Sarbani
Publisher: name: arXiv
Year: 2018
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Asteroseismic large frequency separations possess great diagnostic value. However, their expressions as scaling relations are predicated on homology arguments which may not hold in general, resulting in mass- and temperature-dependent deviations. The first-order asymptotic expressions, which should in principle account for this structural evolution, also deviate more from fitted frequency-separation estimates than do the simple scaling relations, and exhibit qualitatively different behavior. We present a modified asymptotic estimator, and show that these discrepancies can be accounted for by the evolution of the acoustic turning points of the asteroseismic mode cavity, which is typically neglected in first-order asymptotic analysis. This permits us to use a single expression to accurately estimate the large frequency separations of main-sequence, ascending red giant branch, and red clump stellar models, except at transition points between two asymptotic regimes during the subgiant phase of evolution, where the WKB approach fails. The existence of such transition points provides theoretical justification for separately calibrated scaling relations for stars in different evolutionary stages.
description: 12 pages, 9 figures. Accepted for publication in ApJ
Protection and Control Strategies for Shipboard Power Systems
Creators: name: RYAN, DANIEL JOSEPH
Publisher: name: Monash University
Year: 2021
Subjects: subject: 91305 Energy Generation, Conversion and Storage Engineering
subject: FOS: Mechanical engineering
subject: 90607 Power and Energy Systems Engineering (excl. Renewable Power)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: 90608 Renewable Power and Energy Systems Engineering (excl. Solar Cells)

description: This thesis investigates improvements to the reliability and stability of shipboard power systems. Firstly, it proposes a method for protecting large lithium-Ion battery systems on board the ship during external electrical faults. This is challenging due to the high DC fault currents involved. Additionally, the thesis proposes improved control strategies for battery energy storage systems and the propulsion motor drives to more tightly regulate the frequency and voltage of the network. This improved regulation is crucial as it maintains the power system at a stable operating point during large disturbances, and mitigates emergency load shedding or blackouts.
The Double-Time Green's Function Approach to the Two-Dimensional Heisenberg Antiferromagnet with Broken Bonds
Creators: name: Song, Yun
name: Lin, H. Q.
name: Shen, Jue-Lian
Publisher: name: arXiv
Year: 1998
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We improved the decoupling approximation of the double-time Green's function theory, and applied it to study the spin-${1\over 2}$ two-dimensional antiferromagnetic Heisenberg model with broken bonds at finite temperature. Our decoupling approximation is applicable to the spin systems with spatial inhomogeneity, introduced by the local defects, over the whole temperature region. At low temperatures, we observed that the quantum fluctuation is reduced in the neighborhood of broken bond, which is in agreement with previous theoretical expectations. At high temperatures our results showed that the quantum fluctuation close to the broken bond is enhanced. For the two parallel broken bonds cases, we found that there exists a repulsive interaction between the two parallel broken bonds at low temperatures.
description: Revtex, 6 pages, 5 Postscript figures (include)
No unique solution to the seismological problem of standing kink MHD waves
Creators: name: Arregui, Inigo
name: Goossens, Marcel
Publisher: name: arXiv
Year: 2018
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The aim of this paper is to point out that the classic seismological problem using observations and theoretical expressions for the periods and damping times of transverse standing magnetohydrodynamic (MHD) waves in coronal loops is better referred to as a reduced seismological problem. Reduced emphasises the fact that only a small number of characteristic quantities of the equilibrium profiles can be determined. Reduced also implies that there is no unique solution to the full seismological problem. Even the reduced seismological problem does not allow a unique solution. Bayesian inference results support our mathematical arguments and offer insight into the relationship between the algebraic and the probabilistic inversions.
description: 10 pages, accepted in A&A
Local Operator Entanglement in Spin Chains
Creators: name: Mascot, Eric
name: Nozaki, Masahiro
name: Tezuka, Masaki
Publisher: name: arXiv
Year: 2020
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: High Energy Physics - Theory (hep-th)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Understanding how and whether local perturbations can affect the entire quantum system is a fundamental step in understanding non-equilibrium phenomena such as thermalization. This knowledge of non-equilibrium phenomena is applicable for quantum computation, as many quantum computers employ non-equilibrium processes for computations. In this paper, we investigate the evolution of bi- and tripartite operator mutual information of the time-evolution operator and the Pauli spin operators in the one-dimensional Ising model with magnetic field and the disordered Heisenberg model to study the properties of quantum circuits. In the Ising model, the early-time evolution qualitatively follows an effective light cone picture, and the late-time value is well described by Page's value for a random pure state. In the Heisenberg model with strong disorder, we find that many-body localization prevents the information from propagating and being delocalized. We also find an effective Ising Hamiltonian that describes the time evolution of bi- and tripartite operator mutual information for the Heisenberg model in the large disorder regime.
description: 33 pages, 14 figures. Submission to SciPost
Vibrotactile Signal Generation from Texture Images or Attributes using Generative Adversarial Network
Creators: name: Ujitoko, Yusuke
name: Ban, Yuki
Publisher: name: arXiv
Year: 2019
Subjects: subject: Human-Computer Interaction (cs.HC)
subject: FOS: Computer and information sciences

description: Providing vibrotactile feedback that corresponds to the state of the virtual texture surfaces allows users to sense haptic properties of them. However, hand-tuning such vibrotactile stimuli for every state of the texture takes much time. Therefore, we propose a new approach to create models that realize the automatic vibrotactile generation from texture images or attributes. In this paper, we make the first attempt to generate the vibrotactile stimuli leveraging the power of deep generative adversarial training. Specifically, we use conditional generative adversarial networks (GANs) to achieve generation of vibration during moving a pen on the surface. The preliminary user study showed that users could not discriminate generated signals and genuine ones and users felt realism for generated signals. Thus our model could provide the appropriate vibration according to the texture images or the attributes of them. Our approach is applicable to any case where the users touch the various surfaces in a predefined way.
description: accepted for EuroHaptics 2018: Haptics: Science, Technology, and Applications, pp.25-36
Pairing via Index theorem
Creators: name: Lee, Dung-Hai
Publisher: name: arXiv
Year: 1999
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: This work is motivated by a specific point of view: at short distances and high energies the undoped and underdoped cuprates resemble the $π$-flux phase of the t-J model. The purpose of this paper is to present a mechanism by which pairing grows out of the doped $π$-flux phase. According to this mechanism pairing symmetry is determined by a parameter controlling the quantum tunneling of gauge flux quanta. For zero tunneling the symmetry is $d_{x^2-y^2}+id_{xy}$, while for large tunneling it is $d_{x^2-y^2}$. A zero-temperature critical point separates these two limits.
DNA barcoding of fishes from River Diphlu within Kaziranga National Park in northeast India
Creators: name: Boni Amin Laskar
name: Kumar, Vikas
name: Shantanu Kundu
name: Achom Darshan
name: Kaomud Tyagi
name: Chandra, Kailash
Publisher: name: Taylor & Francis
Year: 2019
Subjects: subject: Genetics
subject: FOS: Biological sciences
subject: Evolutionary Biology
subject: 59999 Environmental Sciences not elsewhere classified
subject: FOS: Earth and related environmental sciences
subject: Ecology
subject: 69999 Biological Sciences not elsewhere classified
subject: Marine Biology
subject: Inorganic Chemistry
subject: FOS: Chemical sciences

description: DNA barcoding technique has been gaining importance in biodiversity research for its easy and rapid ability of delineating organisms’ partial DNA sequences into molecular operational taxonomic units (MOTUs), and identification based on referral sequences from expert identified species. We generated mtCOI barcode sequences from morphologically identified fishes from River Diphlu in northeast India. A portion of this river falls within an important rhinoceros and tiger conservation site, the Kaziranga National Park. Partial mtCOI sequences for 103 fish specimens belonging to six orders, 19 families, 37 genera and 47 a priori identified species, were delineated into 48 MOTUs based on reciprocal monophyly criteria in maximum likelihood and Bayesian tree, and 49 groups by automatic barcode gap discovery (ABGD). Morphological and molecular basis of species identification was congruent for around 80% straightforward cases. We contributed barcodes for eight species which either had no barcodes in databases or are having ambiguous barcodes. We detected four ‘near threatened’ and two data deficient species as per the IUCN Red List status, besides a few ‘least concerned’ species. We also observed a wide scope of barcoding studies on fishes from northeast India to cover the endemic species and to resolve the prevailing taxonomic problems.
Global Probes of the Impact of Baryons on Dark Matter Halos
Creators: name: Kochanek, C. S.
name: White, Martin
Publisher: name: arXiv
Year: 2001
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The halo mass function, dn/dM, predicted by hierarchical clustering models can be measured indirectly using dynamical probes like the distribution of gravitational lens image separations, dn/dDelta-theta, or halo circular velocities, dn/d v_c. These dynamical variables depend on the halo structure as well as the halo mass. Since baryonic physics, particularly cooling, significantly modifies the central density structure of dark matter halos, both observational distributions show a feature corresponding to the mass scale below which the baryons in the halo can cool (i.e. galaxies versus clusters). We use simplified but self-consistent models to show that the structural changes to the halos produced by the cooling baryons explain both distributions. Given a fixed halo mass function, matching the observed image separation distribution or local velocity function depends largely on Omega_b through its effects on the cooling time scales. These baryonic effects on the halo structure also affect the evolution of the velocity function of galaxies with redshift.
description: 30 pages, 12 figures
Viscous cosmologies in scalar-tensor theories for Kasner type metrics
Creators: name: Cataldo, M.
name: del Campo, S.
name: Salgado, P.
Publisher: name: arXiv
Year: 2000
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In a viscous Bianchi type I metric of the Kasner form, it is well known that it is not possible to describe an anisotropic physical model of the universe, which satisfies the second law of thermodynamics and the dominant energy condition (DEC) in Einstein's theory of gravity. We examine this problem in scalar-tensor theories of gravity. In this theory we show that it is possible to describe the growth of entropy, keeping the thermodynamics and the dominant energy condition.
description: 6 pages, Latex, accepted in Phys. Rev. D
Eufolivora
Creators: name: Casali, Daniel M
name: Boscaini, Alberto
name: Gaudin, Timothy J
name: Perini, Fernando A
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Eufolivora

description: Eufolivora
PP = 100, age = 34.25 Mya (30.81–38.47).
 All sloths excluding Pseudoglyptodon and Bradypus. It is composed of two major clades, Mylodontoidea and Megatherioidea, and was consistently recovered in all analyses performed in this study.
Eufolivora was supported by eight synapomorphies (five for both methods and three exclusively for BI): parallel lateral edges of the mandibular spout (BI); orbital portion of lacrimal greater than facial portion; presence of middle process of jugal; tip of zygomatic process of squamosal extends anterior to frontoparietal suture (BI); nuchal and exoccipital crests diverge distally (BI); tympanohyal wide distally, contributing to the formation of the stylohyal fossa; fusion of the acromion with the coracoid process of the scapula; and femoral entepicondyle and ectepicondyle strongly projected beyond condyles.
description: Published as part of Casali, Daniel M, Boscaini, Alberto, Gaudin, Timothy J & Perini, Fernando A, 2022, Reassessing the phylogeny and divergence times of sloths (Mammalia: Pilosa: Folivora), exploring alternative morphological partitioning and dating models, pp. 1505-1551 in Zoological Journal of the Linnean Society 196 (4) on page 1522, DOI: 10.1093/zoolinnean/zlac041, http://zenodo.org/record/7381236
Genetic Characterization and Clinical Features of Helicobacter pylori Negative Gastric Mucosa-Associated Lymphoid Tissue Lymphoma
Creators: name: Kiesewetter, Barbara
name: Copie-Bergman, Christiane
name: Levy, Michael
name: Wu, Fangtian
name: Dupuis, Jehan
name: Barau, Caroline
name: Arcaini, Luca
name: Paulli, Marco
name: Lucioni, Marco
name: Bonometti, Arturo
name: Salar, Antonio
name: Fernández-Rodriguez, Concepción
name: Piris, Miguel A.
name: Cucco, Francesco
name: Dobson, Rachel
name: Li, Yan
name: Chen, Zi
name: Robe, Cyrielle
name: Simonitsch-Klupp, Ingrid
name: Wotherspoon, Andrew
name: Raderer, Markus
name: Du, Ming Qing
Publisher: name: Apollo - University of Cambridge Repository
Year: 2021
Subjects: extranodal lymphoma 1
MALT lymphoma 2
Helicobacter pylori 3
NF-κB pathway 4

description: Background: In Western countries, the prevalence of gastric mucosa-associated lymphoid tissue (MALT) lymphoma has declined over the last three decades. Contemporaneously, H. pylori negative gastric MALT lymphoma is increasingly encountered, and their genetic basis and clinical features remain elusive. Methods: A total of 57 cases of H. pylori negative gastric MALT lymphoma were reviewed and investigated for chromosome translocation by fluorescence in-situ hybridization and for somatic mutations by the targeted sequencing of 93 genes. Results: MALT1 translocation, most likely t(11;18)(q21;q21)/BIRC3-MALT1, was detected in 39% (22/57) cases, and IGH translocation was further seen in 12 MALT1-negative cases, together accounting for 60% of the cohort. Targeted sequencing was successful in 35 cases, and showed frequent mutations in NF-κB signaling pathways (TNFAIP3 = 23%, CARD11 = 9%, MAP3K14 = 9%), together affecting 14 cases (40%). The NF-κB pathway mutations were mutually exclusive from MALT1, albeit not IGH translocation, altogether occurring in 86% of cases. There was no significant correlation between the genetic changes and clinicopathological parameters. The patients showed a median of progression-free survival (PFS) of 66.3 months, and a significant superior PFS when treated with systemic versus antibiotic therapy (p = 0.004). Conclusion: H. pylori negative gastric MALT lymphoma is characterized by highly frequent genetic changes in the NF-κB signaling pathways.
Effect of nematic ordering on the elasticity and yielding in disordered polymeric solids
Creators: name: Calonaci, Nicola
name: Giuntoli, Andrea
name: Bernini, Sebastiano
name: Leporini, Dino
Publisher: name: arXiv
Year: 2018
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: The relation between elasticity and yielding is investigated in a model polymer solid by Molecular-Dynamics simulations. By changing the bending stiffness of the chain and the bond length, semicrystalline and disordered glassy polymers - both with bond disorder - as well as nematic glassy polymers with bond ordering are obtained. It is found that in systems with bond disorder the ratio Ty/G between the shear yield strength Ty and the shear modulus G is close to the universal value of the atomic metallic glasses. The increase of the local nematic order in glasses leads to the increase of the shear modulus and the decrease of the shear yield strength, as observed in experiments on nematic thermosets. A tentative explanation of the subsequent reduction of the ratio Ty/G in terms of the distributions of the per-monomer stress is offered.
Positivity Preserving Density Matrix Minimization at Finite Temperatures via Square Root
Creators: name: Leamer, Jacob M.
name: Dawson, William
name: Bondar, Denys I.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present a Wave Operator Minimization (WOM) method for calculating the Fermi-Dirac density matrix for electronic structure problems at finite temperature while preserving physicality by construction using the wave operator, i.e., the square root of the density matrix. WOM models cooling a state initially at infinite temperature down to the desired finite temperature. We consider both the grand canonical (constant chemical potential) and canonical (constant number of electrons) ensembles. Additionally, we show that the number of steps required for convergence is independent of the number of atoms in the system. We hope that the discussion and results presented in this article reinvigorates interest in density matrix minimization methods.
description: 10 pages, 5 figures, 1 algorithm, supplementary information 5 pages, 3 figures
Repetitive rebrightening of EG Cancri: evidence for viscosity decay in the quiescent disk?
Creators: name: Osaki, Yoji
name: Meyer, Friedrich
name: Meyer-Hofmeister, Emmi
Publisher: name: arXiv
Year: 2001
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A WZ Sge-type dwarf nova, EG Cancri, exhibited six consecutive mini-outbursts with a mean interval of about seven days after the end of the main outburst in 1996/1997. Most unusual was that the star abruptly entered into a deep faint minimum after such frantic activities. We propose that this peculiar phenomenon may be understoodin terms of viscosity decay in the cold disk. In this picture, the viscosity is produced by MHD turbulence due to the magneto-rotational instability ('Balbus-Hawley instability') and dies down exponentially with time when the disk becomes cold because the magnetic fields decay due to finite conductivity in the cold disk (Gammie & Menou 1998). But the viscosity is refreshed to a high value every time when a mini-outburst occurs (i.e., the disk becomes hot again). It is argued that a sudden cessation of repetitive mini-outbursts may be brought about by a very small reduction in viscosity or a small increase in its decay rate, which may in turn be produced most likely by stochastic fluctuations of magnetic fields. Numerical simulations based on a simple model reproduce the observed light curve of EG Cancri very well. We discuss possible causes why the reflares after the main outburst occur mostly in the WZ Sge-type stars.
description: 8 pages, 5 figures, accepted for publication in A&A
Bridging Brain and Cognition: A Multilayer Network Analysis of Brain Structural Covariance and General Intelligence in a Developmental Sample of Struggling Learners
Creators: name: Simpson-Kent, Ivan L.
name: Fried, Eiko I.
name: Akarca, Danyal
name: Mareva, Silvana
name: Bullmore, Edward T.
name: The CALM Team, The CALM Team
name: Kievit, Rogier A.
Publisher: name: Apollo - University of Cambridge Repository
Year: 2021
Subjects: general intelligence
cortical volume
fractional anisotropy
brain structural covariance
cognitive network neuroscience
multilayer network analysis

description: Network analytic methods that are ubiquitous in other areas, such as systems neuroscience, have recently been used to test network theories in psychology, including intelligence research. The network or mutualism theory of intelligence proposes that the statistical associations among cognitive abilities (e.g., specific abilities such as vocabulary or memory) stem from causal relations among them throughout development. In this study, we used network models (specifically LASSO) of cognitive abilities and brain structural covariance (grey and white matter) to simultaneously model brain–behavior relationships essential for general intelligence in a large (behavioral, N = 805; cortical volume, N = 246; fractional anisotropy, N = 165) developmental (ages 5–18) cohort of struggling learners (CALM). We found that mostly positive, small partial correlations pervade our cognitive, neural, and multilayer networks. Moreover, using community detection (Walktrap algorithm) and calculating node centrality (absolute strength and bridge strength), we found convergent evidence that subsets of both cognitive and neural nodes play an intermediary role ‘between’ brain and behavior. We discuss implications and possible avenues for future studies.
Magnetic excitations in frustrated fcc type-III antiferromagnet MnS$_2$
Creators: name: Chatterji, T.
name: Regnault, L. P.
name: Ghosh, S.
name: Singh, A.
Publisher: name: arXiv
Year: 2018
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: Spin wave dispersion in the frustrated fcc type-III antiferromagnet MnS$_2$ has been determined by inelastic neutron scattering using a triple-axis spectrometer. Existence of multiple spin wave branches, with significant separation between high-energy and low-energy modes highlighting the intrinsic magnetic frustration effect on the fcc lattice, is explained in terms of a spin wave analysis carried out for the antiferromagnetic Heisenberg model for this $S=5/2$ system with nearest and next-nearest-neighbor exchange interactions. Comparison of the calculated dispersion with spin wave measurement also reveals small suppression of magnetic frustration resulting from reduced exchange interaction between frustrated spins, possibly arising from anisotropic deformation of the cubic structure.
On the solution of the inverse problem for a class of canonical systems corresponding to matrix string equations
Creators: name: Sakhnovich, Alexander
Publisher: name: arXiv
Year: 2021
Subjects: subject: Spectral Theory (math.SP)
subject: Mathematical Physics (math-ph)
subject: Classical Analysis and ODEs (math.CA)
subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 34A55, 34B20, 34L40, 46N20, 47A48, 70H05

description: We consider canonical systems (with $2p\times 2p$ Hamiltonians $H(x)\geq 0$), which correspond to matrix string equations. Direct and inverse problems are solved in terms of Titchmarsh--Weyl and spectral matrix functions and related $S$-nodes. Procedures for solving inverse problems are given.
description: This is the concluding paper in our series of three articles dedicated to canonical systems related to matrix string equations. Two previous articles appeared in arXiv as well: see arXiv:2010.05217 and arXiv:2103.03203
Exact N-vortex solutions to the Ginzburg-Landau equations for kappa=1/sqrt(2)
Creators: name: Efanov, Alexander V.
Publisher: name: arXiv
Year: 1997
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The N-vortex solutions to the two-dimensional Ginzburg - Landau equations for the kappa=1/\sqrt(2) parameter are built. The exact solutions are derived for the vortices with large numbers of the magnetic flux quanta. The size of vortex core is supposed to be much greater than the magnetic field penetration depth. In this limiting case the problem is reduced to the determination of vortex core shape. The corresponding nonlinear boundary problem is solved by means of the methods of the theory of analytic functions.
description: 12 pages in RevTex, 1 Postscript figure