cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
ULF wave transmission across collisionless shocks: 2.5D local hybrid simulations
Creators: name: Kajdic, Primoz
name: Pfau-Kempf, Yann
name: Turc, Lucile
name: Dimmock, Andrew P
name: Palmroth, Minna
name: Takahashi, Kazue
name: Kilpua, Eemilia
name: Soucek, Jan
name: Takahashi, Naoko
name: Preisser, Luis
name: Blanco-Cano, Xochitl
name: Trotta, Domenico
name: Burgess, David
Publisher: name: arXiv
Year: 2022
Subjects: subject: Space Physics (physics.space-ph)
subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: We study the interaction of upstream ultra-low frequency (ULF) waves with collisionless shocks by analyzing the outputs of eleven 2D local hybrid simulation runs. Our simulated shocks have Alfvénic Mach numbers between 4.29-7.42 and their $θ_{BN}$ angles are 15$^\circ$, 30$^\circ$, 45$^\circ$ and 50$^\circ$. The ULF wave foreshocks develop upstream of all of them. The wavelength and the amplitude of the upstream waves exhibit a complex dependence on the shock's M$_A$ and $θ_{BN}$. The wavelength positively correlates with both parameters, with the dependence on $θ_{BN}$ being much stronger. The amplitude of the ULF waves is proportional to the product of the reflected beam velocity and density, which also depend on M$_A$ and $θ_{BN}$. The interaction of the ULF waves with the shock causes large-scale (several tens of upstream ion inertial lengths) shock rippling. The properties of the shock ripples are related to the ULF wave properties, namely thier wavelength and amplitude. In turn, the ripples have a large impact on the ULF wave transmission across the shock because they change local shock properties ($θ_{BN}$, strength), so that different sections of the same ULF wave front encounter shock with different characteristics. Downstream fluctuations do not resemble the upstream waves in terms the wavefront extension, orientation or their wavelength. However some features are conserved in the Fourier spectra of downstream compressive waves that present a bump or flattening at wavelengths approximately corresponding to those of the upstream ULF waves. In the transverse downstream spectra these features are weaker.
To rule by ritual : the theorization of ritual psychology in the bamboo texts of Guodian
Creators: name: Ashton, Clayton Howard
Publisher: name: University of British Columbia
Year: 2017

description: This study examines the development of a theory of ritual psychology in Chinese political thought during the Warring States period (c. 450 - 221 BCE), as found in four Confucian bamboo manuscripts from the Guodian corpus which were discovered in 1993 in a tomb that had been sealed in c. 300 BCE. These four texts, called here the Ritual Authority manuscripts, provide new evidence of a political theory that applied ritual practices to the management of the state, with implications for our understanding of both the development of the Confucian tradition and of the formation of the early Chinese empire. The introduction surveys how the concept of ritual has been framed in studies of Chinese history, and argues that this new evidence of a conscious theorization about ritual psychology should compel us reexamine this topic. Chapter One makes use of the insights offered by the cross-disciplinary field of Ritual Studies to create a working definition of “ritual” as an academic term of analysis, and then examines a range of primary sources from the Warring States period in order to reconstruct the discursive field of meaning encompassed by the Chinese term li, or “ritual propriety,” which was the focus of this theorization. Chapter Two considers the implications of the previous chapter’s insights by examining how ritual practices rely on a sense of historical authority, which embroils these practices in a larger tension between tradition and innovation. Chapter Three examines the development of theories of political authority in the Warring States period, and shows how these presented a fundamental challenge to the Confucian emphasis on ritual practices. Chapter Four turns to the Ritual Authority manuscripts from Guodian and closely examines how they reveal an attempt to incorporate a theory of ritual psychology into a defence of traditional ritual practices. This study finally concludes by considering the larger implications of this intellectual innovation, and suggests several possible directions of future research based on this research.
Adaptive Cholesky Gaussian Processes
Creators: name: Bartels, Simon
name: Stensbo-Smidt, Kristoffer
name: Moreno-Muñoz, Pablo
name: Boomsma, Wouter
name: Frellsen, Jes
name: Hauberg, Søren
Publisher: name: arXiv
Year: 2022
Subjects: subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: We present a method to approximate Gaussian process regression models for large datasets by considering only a subset of the data. Our approach is novel in that the size of the subset is selected on the fly during exact inference with little computational overhead. From an empirical observation that the log-marginal likelihood often exhibits a linear trend once a sufficient subset of a dataset has been observed, we conclude that many large datasets contain redundant information that only slightly affects the posterior. Based on this, we provide probabilistic bounds on the full model evidence that can identify such subsets. Remarkably, these bounds are largely composed of terms that appear in intermediate steps of the standard Cholesky decomposition, allowing us to modify the algorithm to adaptively stop the decomposition once enough data have been observed.
Dynamics and morphology of dendritic flux avalanches in superconducting films
Creators: name: Vestgarden, J. I.
name: Shantsev, D. V.
name: Galperin, Y. M.
name: Johansen, T. H.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We develop a fast numerical procedure for analysis of nonlinear and nonlocal electrodynamics of type-II superconducting films in transverse magnetic fields taking into account realistic boundary conditions. Using this procedure we explore stability of such films with respect to dendritic flux avalanches. The calculated flux patterns are very similar to experimental magneto-optical images of MgB2 and other superconductors, where the avalanche size and morphology change dramatically with temperature. We also find a threshold magnetic field, which agrees with both experiments and linear stability analysis. The simulations predict the temperature rise during an avalanche, where for a sub-microsecond time T ~ 1.5 Tc, and a precursor stage with large thermal fluctuations.
description: 7 pages 7 figures
Place-level urban-rural indices for the United States from 1930 to 2018
Creators: name: Uhl, Johannes H.
name: Hunter, Lori M.
name: Leyk, Stefan
name: Connor, Dylan S.
name: Nieves, Jeremiah J.
name: Hester, Cyrus
name: Talbot, Catherine B.
name: Gutmann, Myron
Publisher: name: arXiv
Year: 2022
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Applications (stat.AP)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Rural-urban classifications are essential for analyzing geographic, demographic, environmental, and social processes across the rural-urban continuum. Most existing classifications are, however, only available at relatively aggregated spatial scales, such as at the county scale in the United States. The absence of rurality or urbanness measures at high spatial resolution poses significant problems when the process of interest is highly localized, as with the incorporation of rural towns and villages into encroaching metropolitan areas. Moreover, existing rural-urban classifications are often inconsistent over time, or require complex, multi-source input data (e.g., remote sensing observations or road network data), thus, prohibiting the longitudinal analysis of rural-urban dynamics. Here, we develop a set of distance- and spatial-network-based methods for consistently estimating the remoteness and rurality of places at fine spatial resolution, over long periods of time. We demonstrate the utility of our approach by constructing indices of urbanness for 30,000 places in the United States from 1930 to 2018 and further test the plausibility of our results against a variety of evaluation datasets. We call these indices the place-level urban-rural index (PLURAL) and make the resulting datasets publicly available (https://doi.org/10.3886/E162941) so that other researchers can conduct long-term, fine-grained analyses of urban and rural change. In addition, due to the simplistic nature of the input data, these methods can be generalized to other time periods or regions of the world, particularly to data-scarce environments.
description: 33 pages, 20 figures
Exploiting symmetries in SDP-relaxations for polynomial optimization
Creators: name: Riener, Cordian
name: Theobald, Thorsten
name: Andrén, Lina Jansson
name: Lasserre, Jean B.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Optimization and Control (math.OC)
subject: Systems and Control (eess.SY)
subject: FOS: Mathematics
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: 90C22, 90C26, 14P05, 05E10

description: In this paper we study various approaches for exploiting symmetries in polynomial optimization problems within the framework of semi definite programming relaxations. Our special focus is on constrained problems especially when the symmetric group is acting on the variables. In particular, we investigate the concept of block decomposition within the framework of constrained polynomial optimization problems, show how the degree principle for the symmetric group can be computationally exploited and also propose some methods to efficiently compute in the geometric quotient.
description: (v3) Minor revision. To appear in Math. of Operations Research
Heisenberg categorification and Hilbert schemes
Creators: name: Cautis, Sabin
name: Licata, Anthony
Publisher: name: arXiv
Year: 2010
Subjects: subject: Quantum Algebra (math.QA)
subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14F05, 19A22, 81R50

description: Given a finite subgroup G of SL(2,C) we define an additive 2-category H^G whose Grothendieck group is isomorphic to an integral form of the Heisenberg algebra. We construct an action of H^G on derived categories of coherent sheaves on Hilbert schemes of points on the minimal resolutions of C^2/G.
description: 53 pages
Bootstrapping data arrays of arbitrary order
Creators: name: Owen, Art B.
name: Eckles, Dean
Publisher: name: arXiv
Year: 2011
Subjects: subject: Methodology (stat.ME)
subject: Applications (stat.AP)
subject: Computation (stat.CO)
subject: FOS: Computer and information sciences

description: In this paper we study a bootstrap strategy for estimating the variance of a mean taken over large multifactor crossed random effects data sets. We apply bootstrap reweighting independently to the levels of each factor, giving each observation the product of independently sampled factor weights. No exact bootstrap exists for this problem [McCullagh (2000) Bernoulli 6 285-301]. We show that the proposed bootstrap is mildly conservative, meaning biased toward overestimating the variance, under sufficient conditions that allow very unbalanced and heteroscedastic inputs. Earlier results for a resampling bootstrap only apply to two factors and use multinomial weights that are poorly suited to online computation. The proposed reweighting approach can be implemented in parallel and online settings. The results for this method apply to any number of factors. The method is illustrated using a 3 factor data set of comment lengths from Facebook.
description: Published in at http://dx.doi.org/10.1214/12-AOAS547 the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Suppression of the high $p_T$ charged hadron $R_{AA}$ at the LHC
Creators: name: Majumder, A.
name: Shen, C.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We present a parameter free postdiction of the high-$p_T$ charged-hadron nuclear modification factor ($R_{AA}$) in two centralities, measured by the CMS collaboration in $Pb$-$Pb$ collisions at the Large Hadron Collider (LHC). The evolution of the bulk medium is modeled using viscous fluid dynamics, with parameters adjusted to describe the soft hadron yields and elliptic flow. Assuming the dominance of radiative energy loss, we compute the medium modification of the $R_{AA}$ using a perturbative QCD based formalism, the higher twist scheme. The transverse momentum diffusion coefficient $\hat{q}$ is assumed to scale with the entropy density and normalized by fitting the $R_{AA}$ in the most central $Au$-$Au$ collisions at the Relativistic Heavy-Ion Collider (RHIC). This set up is validated in non-central $Au$-$Au$ collisions at RHIC and then extrapolated to $Pb$-$Pb$ collisions at the LHC, keeping the relation between $\hat{q}$ and entropy density unchanged. We obtain a satisfactory description of the CMS $R_{AA}$ over the $p_{T}$ range from 10-100 GeV.
description: 4 pages, 3 figures, revtex4, new experimental data used, new calculations with systematic error bands, changed abstract and contents, conclusions unchanged
Elliptical Slice Sampling for Probabilistic Verification of Stochastic Systems with Signal Temporal Logic Specifications
Creators: name: Scher, Guy
name: Sadraddini, Sadra
name: Tedrake, Russ
name: Kress-Gazit, Hadas
Publisher: name: arXiv
Year: 2022
Subjects: subject: Systems and Control (eess.SY)
subject: Robotics (cs.RO)
subject: FOS: Electrical engineering, electronic engineering, information engineering
subject: FOS: Computer and information sciences
subject: I.2.9

description: Autonomous robots typically incorporate complex sensors in their decision-making and control loops. These sensors, such as cameras and Lidars, have imperfections in their sensing and are influenced by environmental conditions. In this paper, we present a method for probabilistic verification of linearizable systems with Gaussian and Gaussian mixture noise models (e.g. from perception modules, machine learning components). We compute the probabilities of task satisfaction under Signal Temporal Logic (STL) specifications, using its robustness semantics, with a Markov Chain Monte-Carlo slice sampler. As opposed to other techniques, our method avoids over-approximations and double-counting of failure events. Central to our approach is a method for efficient and rejection-free sampling of signals from a Gaussian distribution such that satisfy or violate a given STL formula. We show illustrative examples from applications in robot motion planning.
description: Submitted to HSCC 2022
Hunting for Massive Black Holes in Dwarf Galaxies
Creators: name: Reines, Amy E.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Despite traditional thinking, an appreciable population of massive black holes may be lurking in dwarf galaxies. Prior to the last decade, nearly all massive black holes were found in the nuclei of giant galaxies and the existence of massive black holes in dwarf galaxies was highly controversial. The field has now been transformed with a growing community of researchers working on a variety of observational studies and theoretical models of dwarf galaxies hosting massive black holes. Work in this area is not only important for a holistic understanding of dwarf galaxy evolution and feedback, but it may just tell us how the first "seeds" of massive black holes formed in the early Universe. In this Perspective, I discuss the current state of the field as well as future prospects. I also present new insights on the demographics of nearby dwarf galaxies, which can be used to help constrain the black hole occupation/active fraction as a function of mass and dwarf galaxy type.
description: Invited Nature Astronomy Perspective (published 21 Jan 2022). SharedIt link: https://rdcu.be/cFAZF
A simplicial approach to spaces of homomorphisms
Creators: name: Villarreal Herrera, Bernardo
Publisher: name: University of British Columbia
Year: 2017

description: Let G be a real linear algebraic group and L a finitely generated cosimplicial group. We prove that the space of homomorphisms Hom(Ln;G) has a homotopy stable decomposition for each n ≥ 1. When G is a compact Lie group, we show that the decomposition is G-equivariant with respect to the induced action of conjugation by elements of G. In particular, under these hypotheses on G, we obtain stable decompositions for Hom(Fqn;G) and Rep(Fqn;G) respectively, where Fqn are the finitely generated free nilpotent groups of nilpotency class q-1. The spaces Hom(Ln;G) assemble into a simplicial space Hom(L;G). When G=U we show that its geometric realization B(L;U) has a non-unital E-infinity-ring space structure whenever Hom(L0;U(m)) is path connected for all m ≥ 0. We describe the connected components of Hom(Fqn;SU(2)) arising from non-commuting q-nilpotent n-tuples. We prove this by showing that all these n-tuples are conjugated to n-tuples consisting of elements in the the generalized quaternion groups Q2q in SU(2), of order 2^q. Using this result, we exhibit the homotopy type of SHom(Fqn;SU(2)) and a homotopy description of the classifying spaces B(q;SU(2)) of transitionally q-nilpotent principal SU(2)-bundles. The above computations are also done for SO(3) and U(2). Finally, for q = 2, the space B(2;G) is denoted BcomG, and we compute the integral cohomology ring for the Lie groups G = SU(2) andU(2). We also include cohomology calculations for the spaces BcomQ2q .
Extremal spectral properties of Lawson tau-surfaces and the Lamé equation
Creators: name: Penskoi, Alexei V.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Spectral Theory (math.SP)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 58E11, 58J50

description: Extremal spectral properties of Lawson tau-surfaces are investigated. The Lawson tau-surfaces form a two-parametric family of tori or Klein bottles minimally immersed in the standard unitary three-dimensional sphere. A Lawson tau-surface carries an extremal metric for some eigenvalue of the Laplace-Beltrami operator. Using theory of the Lamé equation we find explicitly these extremal eigenvalues.
description: LaTeX, 17 pages; v5: typos corrected. arXiv admin note: supercedes arXiv:1008.2954
Feature space reduction as data preprocessing for the anomaly detection
Creators: name: Bilik, Simon
name: Horak, Karel
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: In this paper, we present two pipelines in order to reduce the feature space for anomaly detection using the One Class SVM. As a first stage of both pipelines, we compare the performance of three convolutional autoencoders. We use the PCA method together with t-SNE as the first pipeline and the reconstruction errors based method as the second. Both methods have potential for the anomaly detection, but the reconstruction error metrics prove to be more robust for this task. We show that the convolutional autoencoder architecture doesn't have a significant effect for this task and we prove the potential of our approach on the real world dataset.
description: 27th Conference STUDENT EEICT 2020, Brno University of Technology
Higher integrability and stability of $(p,q)$-quasiminimizers
Creators: name: Nastasi, Antonella
name: Camacho, Cintia Pacchiano
Publisher: name: arXiv
Year: 2022
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 31E05, 30L99, 46E35

description: Using purely variational methods, we prove local and global higher integrability results for upper gradients of quasiminimizers of a $(p,q)$-Dirichlet integral with fixed boundary data, assuming it belongs to a slightly better Newtonian space. We also obtain a stability property with respect to the varying exponents $p$ and $q$. The setting is a doubling metric measure space supporting a Poincaré inequality.
Space-based Gravitational Wave Observatories
Creators: name: Gair, Jonathan R
name: Hewitson, Martin
name: Petiteau, Antoine
name: Mueller, Guido
Publisher: name: arXiv
Year: 2022
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: In this article, which will appear as a chapter in the Handbook of Gravitational Wave Astronomy, we will describe the detection of gravitational waves with space-based interferometric gravitational wave observatories. We will provide an overview of the key technologies underlying their operation, illustrated using the specific example of the Laser Interferometer Space Antenna (LISA). We will then give an overview of data analysis strategies for space-based detectors, including a description of time-delay interferometry, which is required to suppress laser frequency noise to the necessary level. We will describe the main sources of gravitational waves in the millihertz frequency range targeted by space-based detectors and then discuss some of the key science investigations that these observations will facilitate. Once again, quantitative statements given here will make reference to the capabilities of LISA, as that is the best studied mission concept. Finally, we will describe some of the proposals for even more sensitive space-based detectors that could be launched further in the future.
description: 74 pages, 17 figures, contribution to Handbook of Gravitational Wave Astronomy
Embers of Active Galactic Nuclei: Tidal Disruption Events and Quasiperiodic Eruptions
Creators: name: Jiang, Ning
name: Pan, Zhen
Publisher: name: arXiv
Year: 2025
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Recent observations have confirmed the direct association between tidal disruption events (TDEs) and quasiperiodic eruptions (QPEs). In addition, TDE hosts and QPE hosts are statistically found to be similar in their morphological properties and in the strong overrepresentation of poststarburst galaxies. Particularly, both of them show an intriguing preference for extending emission line regions (EELRs), which are indicative of recently faded active galactic nuclei (AGNs). This further suggests that QPEs might be produced following TDEs involving supermassive black holes at a particular stage, when the AGN activity has recently ceased. Moreover, in the framework of "QPEs=extreme mass ratio inspiral (EMRI) + accretion disk" model, a large fraction of QPE EMRIs are inferred to be quasi-circular from the QPE timing, indicating that they are wet EMRIs that were formed in the AGN disk during a previous AGN phase. Based on these facts, we propose a unified scenario that connects these three phenomena: AGN activities boost both the TDE rate and the formation rate of low-eccentricity EMRIs, consequently TDEs are preferentially found in recently faded AGNs instead of in ongoing AGNs due to selection effects, and QPEs are also preferentially found in recently faded AGNs where TDEs frequently feed a misaligned accretion disk to the EMRI.
description: Publication in ApJL (983,L18). 2 Tables and 1 Figure
Treatment Planning for Pituitary Adenomas - A Comparison of Flatness Filter Free and Flat Beam Plans
Creators: name: Treutwein, Marius
name: Steger, Felix
name: Kölbl, Oliver
name: Dobler, Barbara
Publisher: name: Universität Regensburg
Year: 2018
Subjects: subject: pituitary adenoma, flatness filter free, FFF, IMRT, VMAT
subject: 530 Physik
subject: 610 Medizin

description: Introduction Radiotherapy of pituitary adenomas is often applied as postoperative therapy of tumors that cannot be removed completely. Fluence modulating techniques like IMRT or VMAT support the use of the flatness filter free (FFF) mode in modern linear accelerators. In this mode a considerably higher dose rate is achieved by omitting the flatness filter. This planning study compares different plans for patients with pituitary adenoma. The plans were optimized using both modes: flattened beam (FB) and FFF. The aim of this study is to evaluate the plan quality. Material and Methods Data sets of 11 patients with pituitary adenoma were used for this retrospective planning study. The objectives for the PTV were set to a minimum dose of 49.4Gy and a maximum dose of 51.4Gy in 28 fractions, aiming for a fraction dose of 1.8Gy. Further objectives were set for the following regions of interest (ROI): brain, brainstem, chiasm, and both lenses, bulbs, lacrimal glands, and parotids. The planning was performed with the treatment planning system (TPS) Oncentra External Beam v4.5 (Elekta AB, Sweden) using the collapsed cone algorithm. In both modes (FB and FFF) IMRT plans with nine equispaced coplanar fields were generated; in a second variant a tenth non-coplanar field was added. Similarly two VMAT plans were optimized: one single arc rotation (182°-178°), and the second with an added half rotation in the sagittal patient plane (0°-180°). The applied linac Synergy Agility (Elekta AB, Sweden) offers a dose rate of 550MU/min (FB) and 1700MU/min (FFF). The leaves have a width of 5mm projected to the isocenter. The following parameters were evaluated: the average dose DAv to the PTV, homogeneity index HI, and the conformity index CI. For all plans the observance of the objectives for the organs at risk given in table 1 was investigated. Results For both modes FB and FFF the dose volume statistics are very close. With some minor exceptions the objectives for the ROIs are met. Only the maximum dose to the chiasm is slightly exceeded in most cases, as it is part of the PTV. Regarding the PTV (HI and CI) pronounced differences are found in the comparison of IMRT and VMAT. The distinction between coplanar and non-coplanar techniques is less important. Discussion The difference in the plan quality of FB and FFF plans is of no clinical importance. A decision for the preferred treatment technique will therefore be taken based on measurements of the delivery time and peripheral dose which will follow. All non-coplanar techniques will require more linac time due to couch rotations without showing advantages in plan quality.
description: DOI bezieht sich auf den gesamten Tagungsband.
The Fermi Bubbles. I. Possible Evidence for Recent AGN Jet Activity in the Galaxy
Creators: name: Guo, Fulai
name: Mathews, William G.
Publisher: name: arXiv
Year: 2011
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The Fermi Gamma-ray Space Telescope reveals two large gamma-ray bubbles in the Galaxy, which extend about 50 degrees (~ 10 kpc) above and below the Galactic center (GC) and are symmetric about the Galactic plane. Using axisymmetric hydrodynamic simulations with a self-consistent treatment of the dynamical cosmic ray (CR) - gas interaction, we show that the bubbles can be created with a recent active galactic nucleus (AGN) jet activity about 1 - 3 Myr ago, which was active for a duration of ~ 0.1 - 0.5 Myr. The bipolar jets were ejected into the Galactic halo along the rotation axis of the Galaxy. Near the GC, the jets must be moderately light with a typical density contrast 0.001
description: Revised version, accepted for publication in ApJ. 17 pages, 11 figures
Deploying an inter-European quantum network
Creators: name: Ribezzo, Domenico
name: Zahidy, Mujtaba
name: Vagniluca, Ilaria
name: Biagi, Nicola
name: Francesconi, Saverio
name: Occhipinti, Tommaso
name: Oxenløwe, Leif K.
name: Lončarić, Martin
name: Cvitić, Ivan
name: Stipčević, Mario
name: Pušavec, Žiga
name: Kaltenbaek, Rainer
name: Ramšak, Anton
name: Cesa, Francesco
name: Giorgetti, Giorgio
name: Scazza, Francesco
name: Bassi, Angelo
name: De Natale, Paolo
name: Cataliotti, Francesco Saverio
name: Inguscio, Massimo
name: Bacco, Davide
name: Zavatta, Alessandro
Publisher: name: arXiv
Year: 2022
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Around forty years have passed since the first pioneering works have introduced the possibility of using quantum physics to strongly enhance communications safety. Nowadays Quantum Cryptography, and in particular, Quantum Key Distribution (QKD) exited the physics laboratories to become commercial technologies that increasingly trigger the attention of States, military forces, banks, and private corporations. This work takes on the challenge of bringing QKD closer to a consumer technology: optical fibers deployed and used by telecommunication companies of different States have been used to realize a quantum network, the first-ever connecting three different countries. This pushes towards the necessary coexistence of QKD and classical communications on the same infrastructure, which currently represents a main limit of this technology. Our network connects Trieste to Rijeka and Ljubljana via a trusted node in Postojna; a key rate of over 3 kbps has been achieved in the shortest link, and a 7-hour long measurement has demonstrated the system stability and reliability. Finally, the network has been used for a public demonstration of QKD at the G20 Digital Ministers' Meeting in Trieste. The reported experimental results, together with the significant interest that one of the most important events of international politics has attracted, showcase the maturity of the QKD technology bundle, placing it in the spotlight for consumer applications in the near term.
description: 8 pages, 3 figures
title: "Statua di fanciullo ammantato", arte romana, inv. CVIC (ITA/EN)
title: Scheda catalogo digitale Borghese
titleType: AlternativeTitle
Creators: name: Ciccarello, Giulia
name: Galleria Borghese
Publisher: name: Galleria Borghese
Year: 2024

description: Pubblicazione delle schede delle opere conservate nel museo ed estratte dal catalogo digitale di

Galleria Borghese, nelle due versioni esistenti online, in italiano e inglese.

Collegamento al catalogo digitale:

ITA: https://www.collezionegalleriaborghese.it/

EN: https://www.collezionegalleriaborghese.it/en
Topological phases and fractional excitations of the exciton condensate in a special class of bilayer systems
Creators: name: Hao, Ningning
name: Zhang, Ping
name: Wang, Yupeng
Publisher: name: arXiv
Year: 2010
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We study the exciton condensate in zero temperature limit in a special class of electron-hole bilayer systems adjacent to insulating ferromagnetic films. With the self-consistent mean-field approximation, we find that the Rashba spin-orbit interaction in the electron and hole layers can induce the p \pm ip or p pairing states depending on the different magnetization of the overlapped ferromagnetic films. Correspondingly, the topologically nontrivial or trivial phases emerge. Furthermore, in the topologically nontrivial phase, the quasiparticle excitations of the U(1) vortex are attached to fractional quantum numbers and obey Abelian statistics.
description: 7 pages, 5 figures
The positive-negative mode link between brain connectivity, demographics, and behavior: A pre-registered replication of Smith et al. 2015
Creators: name: Goyal1, Nikhil
name: Moraczewski, Dustin
name: Bandettini, Peter A.
name: Finn, Emily S.
name: Thomas, Adam G.
Publisher: name: arXiv
Year: 2022
Subjects: subject: Neurons and Cognition (q-bio.NC)
subject: FOS: Biological sciences

description: In mental health research, it has proven difficult to find measures of brain function that provide reliable indicators of mental health and well-being, including susceptibility to mental health disorders. Recently, a family of data-driven analyses have provided such reliable measures when applied to large, population-level datasets. In the current pre-registered replication study, we show that the canonical correlation analysis (CCA) methods previously developed using resting-state MRI functional connectivity and subject measures of cognition and behavior from healthy adults are also effective in measuring well-being (a "positive-negative axis") in an independent developmental dataset. Our replication was successful in two out of three of our pre-registered criteria, such that a primary CCA mode's weights displayed a significant positive relationship and explained a significant amount of variance in both functional connectivity and subject measures. The only criteria that was not successful was that compared to other modes the magnitude of variance explained by the primary CCA mode was smaller than predicted, a result which could indicate a developmental trajectory of a primary mode. This replication establishes a signature neurotypical relationship between connectivity and phenotype, opening new avenues of research in neuroscience with clear clinical applications.
description: Accepted for publication in Royal Society Open Science on 2021-12-21
The Unexplored Terrain of Compiler Warnings
Creators: name: Kudrjavets, Gunnar
name: Kumar, Aditya
name: Nagappan, Nachiappan
name: Rastogi, Ayushi
Publisher: name: arXiv
Year: 2022
Subjects: subject: Software Engineering (cs.SE)
subject: FOS: Computer and information sciences

description: The authors' industry experiences suggest that compiler warnings, a lightweight version of program analysis, are valuable early bug detection tools. Significant costs are associated with patches and security bulletins for issues that could have been avoided if compiler warnings were addressed. Yet, the industry's attitude towards compiler warnings is mixed. Practices range from silencing all compiler warnings to having a zero-tolerance policy as to any warnings. Current published data indicates that addressing compiler warnings early is beneficial. However, support for this value theory stems from grey literature or is anecdotal. Additional focused research is needed to truly assess the cost-benefit of addressing warnings.
description: 2 pages. To be published in 44nd International Conference on Software Engineering: Software Engineering in Practice (ICSE-SEIP '22), May 21-29, 2022, Pittsburgh, PA, USA
SIFT and SURF based feature extraction for the anomaly detection
Creators: name: Bilik, Simon
name: Horak, Karel
Publisher: name: arXiv
Year: 2022
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: Artificial Intelligence (cs.AI)
subject: FOS: Computer and information sciences

description: In this paper, we suggest a way, how to use SIFT and SURF algorithms to extract the image features for anomaly detection. We use those feature vectors to train various classifiers on a real-world dataset in the semi -supervised (with a small number of faulty samples) manner with a large number of classifiers and in the one-class (with no faulty samples) manner using the SVDD and SVM classifier. We prove, that the SIFT and SURF algorithms could be used as feature extractors, that they could be used to train a semi-supervised and one-class classifier with an accuracy around 89\% and that the performance of the one-class classifier could be comparable to the semi-supervised one. We also made our dataset and source code publicly available.
description: 28th Conference STUDENT EEICT 2022, Brno University of Technology
Routes towards the experimental observation of the large fluctuations due to chaos-assisted tunneling effects with cold atoms; selected for a highlight siehe "andere URL zum Volltext"
Creators: name: Dubertrand, Rémy
name: Billy, J.
name: Guéry-Odelin, D.
name: Georgeot, B.
name: Lemarié, G.
Publisher: name: Universität Regensburg
Year: 2016
Subjects: subject: 530 Physik

description: In the presence of a complex classical dynamics associated with amixed phase space, a quantum wave function can tunnel between two stable islands through the chaotic sea, an effect that has no classical counterpart. This phenomenon, referred to as chaos-assisted tunneling, is characterized by large fluctuations of the tunneling rate when a parameter is varied. To date, the full extent of this effect as well as the associated statistical distribution have never been observed in a quantum system. Here, we analyze the possibility of characterizing these effects accurately in a cold-atom experiment. Using realistic values of the parameters of an experimental setup, we examine through analytical estimates and extensive numerical simulations a specific system that can be implemented with cold atoms, the atomic modulated pendulum. We assess the efficiency of three possible routes to observe in detail chaos-assisted tunneling properties. Our main conclusion is that due to the fragility of the symmetry between positive and negative momenta as a function of quasimomentum, it is very challenging to use tunneling between classical islands centered on fixed points with opposite momentum. We show that it is more promising to use islands symmetric in position space, and characterize the regime where it could be done. The proposed experiment could be realized with current state-of-the-art technology.
The biHecke monoid of a finite Coxeter group and its representations
Creators: name: Hivert, Florent
name: Schilling, Anne
name: Thiéry, Nicolas M.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 20M30, 20F55 (Primary) 06D75, 16G99, 20C08 (Secondary)

description: For any finite Coxeter group W, we introduce two new objects: its cutting poset and its biHecke monoid. The cutting poset, constructed using a generalization of the notion of blocks in permutation matrices, almost forms a lattice on W. The construction of the biHecke monoid relies on the usual combinatorial model for the 0-Hecke algebra H_0(W), that is, for the symmetric group, the algebra (or monoid) generated by the elementary bubble sort operators. The authors previously introduced the Hecke group algebra, constructed as the algebra generated simultaneously by the bubble sort and antisort operators, and described its representation theory. In this paper, we consider instead the monoid generated by these operators. We prove that it admits |W| simple and projective modules. In order to construct the simple modules, we introduce for each w in W a combinatorial module T_w whose support is the interval [1,w]_R in right weak order. This module yields an algebra, whose representation theory generalizes that of the Hecke group algebra, with the combinatorics of descents replaced by that of blocks and of the cutting poset.
description: v2: Added complete description of the rank 2 case (Section 7.3) and improved proof of Proposition 7.5. v3: Final version (typo fixes, picture improvements) 66 pages, 9 figures Algebra and Number Theory, 2013. arXiv admin note: text overlap with arXiv:1108.4379 by other authors
Inferring periodic orbits from spectra of simply shaped microlasers
Creators: name: Lebental, M.
name: Djellali, N.
name: Arnaud, C.
name: Lauret, J.-S.
name: Zyss, J.
name: Dubertrand, Rémy
name: Schmit, C.
name: Bogomolny, E.
Publisher: name: Universität Regensburg
Year: 2007
Subjects: subject: 530 Physik
subject: 42.55.Sa, 05.45.Mt, 03.65.Sq, 42.60.Da

description: Dielectric microcavities are widely used as laser resonators and characterizations of their spectra are of interest for various applications. We experimentally investigate microlasers of simple shapes (Fabry-Perot, square, pentagon, and disk). Their lasing spectra consist mainly of almost equidistant peaks and the distance between peaks reveals the length of a quantized periodic orbit. To measure this length with a good precision, it is necessary to take into account different sources of refractive index dispersion. Our experimental and numerical results agree with the superscar model describing the formation of long-lived states in polygonal cavities. The limitations of the two-dimensional approximation are briefly discussed in connection with microdisks.
The CMB Bispectrum
Creators: name: Fergusson, J. R.
name: Liguori, M.
name: Shellard, E. P. S.
Publisher: name: arXiv
Year: 2010
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We use a separable mode expansion estimator with WMAP data to estimate the bispectrum for all the primary families of non-Gaussian models. We review the late-time mode expansion estimator methodology which can be applied to any non-separable primordial and CMB bispectrum model, and we demonstrate how the method can be used to reconstruct the CMB bispectrum from an observational map. We extend the previous validation of the general estimator using local map simulations. We apply the estimator to the coadded WMAP 5-year data, reconstructing the WMAP bispectrum using $l<500$ multipoles and $n=31$ orthonormal 3D eigenmodes. We constrain all popular nearly scale-invariant models, ensuring that the theoretical bispectrum is well-described by a convergent mode expansion. Constraints from the local model $ \fnl=54.4\pm 29.4$ and the equilateral model $\fnl=143.5\pm 151.2$ ($\Fnl = 25.1\pm 26.4$) are consistent with previously published results. (Here, we use a nonlinearity parameter $\Fnl$ normalised to the local case, to allow more direct comparison between different models.) Notable new constraints from our method include those for the constant model $\Fnl = 35.1 \pm 27.4 $, the flattened model $\Fnl = 35.4\pm 29.2$, and warm inflation $\Fnl = 10.3\pm 27.2$. We investigate feature models surveying a wide parameter range in both the scale and phase, and we find no significant evidence of non-Gaussianity in the models surveyed. We propose a measure $\barFnl$ for the total integrated bispectrum and find that the measured value is consistent with the null hypothesis that CMB anisotropies obey Gaussian statistics. We argue that this general bispectrum survey with the WMAP data represents the best evidence for Gaussianity to date and we discuss future prospects, notably from the Planck satellite.
Bloch points in nanostrips
Creators: name: Lang, Martin
name: Beg, Marijan
name: Hovorka, Ondrej
name: Fangohr, Hans
Publisher: name: arXiv
Year: 2022
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Complex magnetic materials hosting topologically non-trivial particle-like objects such as skyrmions are under intensive research and could fundamentally change the way we store and process data. One important class of materials are helimagnetic materials with Dzyaloshinskii-Moriya interaction. Recently, it was demonstrated that nanodisks consisting of two layers with opposite chirality can host a single stable Bloch point of two different types at the interface between the layers. Using micromagnetic simulations we show that FeGe nanostrips consisting of two layers with opposite chirality can host multiple coexisting Bloch points in an arbitrary combination of the two different types. We show that the number of Bloch points that can simultaneously coexist depends on the strip geometry and the type of the individual Bloch points. Our simulation results allow us to predict strip geometries suitable for an arbitrary number of Bloch points. We show an example of an 80-Bloch-point configuration verifying the prediction.
description: 12 pages, 6 figures, and 2 pages and 3 figures supplement
A new approach to information loss (no) problem for Black Holes
Creators: name: Pappas, Nikolaos D.
Publisher: name: arXiv
Year: 2010
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: The discovery that black holes emit thermal type radiation changed radically our perception of their behavior. Until then, their interior was considered as causally disconnected from the rest of the universe, so any kind of information, that went down the black hole, was believed to remain eternally trapped in it. The emission of the aforementioned radiation means that some amount of information eventually returns to the universe outside the black hole. The question then rises whether it is the whole of this information that goes back to the universe during the black hole evaporation or not. Numerous theories supporting either information preservation or extinction have been developed ever since. A new idea is proposed, based on a deep re-examination of what information is and what are its properties. We postulate that not all kinds of information are of equal importance to nature and, as a result, some of them should be preserved under any conditions, while the rest are allowed to be destroyed, so both preservation and destruction of information is what actually happens during the black hole formation/evaporation process.
description: 6 pages, no figures
Quantification of internal dosimetry in PET patients II: Individualized Monte Carlo-based dosimetry for [18F]Fluorocholine PET
Creators: name: Neira, Sara
name: Guiu-Souto, Jacobo
name: Pais, Paulino
name: de Llano, Sofía Rodríguez Martínez
name: Fernández, Carlos
name: Pubul, Virginia
name: Ruibal, Álvaro
name: Pombar, Miguel
name: Gago-Arias, Araceli
name: Pardo-Montero, Juan
Publisher: name: arXiv
Year: 2022
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: Purpose: To obtain individualized internal doses with a Monte Carlo method in patients undergoing diagnostic FCH-PET studies and to compare such doses with the MIRD method calculations. Methods: A patient cohort of 17 males were imaged after intravenous administration of a mean FCH activity of 244.3 MBq. The resulting PET/CT images were processed in order to generate individualized input source and geometry files for dose computation with the MC tool GATE. The resulting dose estimates were studied and compared to the MIRD method with two different computational phantoms. Mass correction of the S-factors was applied when possible. Potential sources of uncertainty were closely examined: the effect of partial body images, urinary bladder emptying, and biokinetic modeling. Results: Large differences in doses between our methodology and the MIRD method were found, generally in the range of $\pm$25%, and up to $\pm$120% for some cases. The mass scaling showed improvements, especially for non-walled and high-uptake tissues. Simulations of the urinary bladder emptying showed negligible effects on doses to other organs, with the exception of the prostate. Dosimetry based on partial PET/CT images (excluding the legs) resulted in an over-estimation of mean doses to bone, skin, and remaining tissues, and minor differences in other organs/tissues. Estimated uncertainties associated with the biokinetics of FCH introduce variations of cumulated activities in the range of $\pm$10% in the high-uptake organs. Conclusions: The MC methodology allows for a higher degree of dosimetry individualization than the MIRD methodology, which in some cases leads to important differences in dose values. Dosimetry of FCH-PET based on a single partial PET study seems viable due to the particular biokinetics of FCH, even though some correction factors may need to be applied to estimate mean skin/bone doses.