cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Islands and current singularities in quasisymmetric toroidal plasmas
Creators: name: Rodríguez, Eduardo
name: Bhattacharjee, Amitava
Publisher: name: arXiv
Year: 2021
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: The presence of current singularities in a quasisymmetric magnetic field is explored. Quasisymmetry is shown effective in isolating Pfirsch-Schlüter singularities, to leading order, to a single magnetic surface resonant with the helicity of the symmetry. The effects of pressure driven currents are analysed, indicating that exclusion of this surface from the plasma volume reduces the potential opening of islands, but does not generally eliminate them completely due to higher order asymmetric geometric effects. These three-dimensional effects are contained in quasisymmetry and indicate the complexity of finding consistent solutions and their potential sensitivity. The $δ$-function current singularities show a distinct quasisymmetric behaviour only when the higher-order Fourier content of $B$ is relevant for the resistive stability parameter $D_R$ (not included in leading-order near-axis expansions). In such scenarios, quasisymmetry proves advantageous, both in simplicity and avoidance of amplification by low-order rational surfaces.
Intersecting Defects and Supergroup Gauge Theory
Creators: name: Kimura, Taro
name: Nieri, Fabrizio
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Quantum Algebra (math.QA)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We consider 5d supersymmetric gauge theories with unitary groups in the $Ω$-background and study codim-2/4 BPS defects supported on orthogonal planes intersecting at the origin along a circle. The intersecting defects arise upon implementing the most generic Higgsing (geometric transition) to the parent higher dimensional theory, and they are described by pairs of 3d supersymmetric gauge theories with unitary groups interacting through 1d matter at the intersection. We explore the relations between instanton and generalized vortex calculus, pointing out a duality between intersecting defects subject to the $Ω$-background and a deformation of supergroup gauge theories, the exact supergroup point being achieved in the self-dual or unrefined limit. Embedding our setup into refined topological strings and in the simplest case when the parent 5d theory is Abelian, we are able to identify the supergroup theory dual to the intersecting defects as the supergroup version of refined Chern-Simons theory via open/closed duality. We also discuss the BPS/CFT side of the correspondence, finding an interesting large rank duality with super-instanton counting.
description: v1: 50 pages; v2: 51 pages, added more references, minor comments and report n; v3: published version
Ram pressure stripping of disc galaxies orbiting in clusters. I. Mass and radius of the remaining gas disc
Creators: name: Roediger, E.
name: Brueggen, M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the first 3D hydrodynamical simulations of ram pressure stripping of a disc galaxy orbiting in a galaxy cluster. Along the orbit, the ram pressure that this galaxy experiences varies with time. In this paper, we focus on the evolution of the radius and mass of the remaining gas disc and compare it with the classical analytical estimate proposed by Gunn & Gott 1972. We find that this simple estimate works well in predicting the evolution of the radius of the remaining gas disc. Only if the ram pressure increases faster than the stripping timescale, the disc radius remains larger than predicted. However, orbits with such short ram pressure peaks are unlikely to occur in other than compact clusters. Unlike the radius evolution, the mass loss history for the galaxy is not accurately described by the analytical estimate. Generally, in the simulations the galaxy loses its gas more slowly than predicted.
description: 11 pages, 11 figures, accepted by MNRAS, high resolution pdf version available at http://www.faculty.iu-bremen.de/eroediger/PAPERS/eroediger_crossing.pdf
Period-two cycles in a feed-forward layered neural network model with symmetric sequence processing
Creators: name: Metz, F. L.
name: Theumann, W. K.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: The effects of dominant sequential interactions are investigated in an exactly solvable feed-forward layered neural network model of binary units and patterns near saturation in which the interaction consists of a Hebbian part and a symmetric sequential term. Phase diagrams of stationary states are obtained and a new phase of cyclic correlated states of period two is found for a weak Hebbian term, independently of the number of condensed patterns $c$.
description: 8 pages and 5 figures
On cost design in applications of optimal control
Creators: name: Jouini, Taouba
name: Rantzer, Anders
Publisher: name: arXiv
Year: 2021
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: A new approach to feedback control design based on optimal control is proposed. Instead of expensive computations of the value function for different penalties on the states and inputs, we use a control Lyapunov function that amounts to be a value function of an optimal control problem with suitable cost design and then study combinations of input and state penalty that are compatible with this value function. This drastically simplifies the role of the Hamilton-Jacobi-Bellman equation, since it is no longer a partial differential equation to be solved, but an algebraic relationship between different terms of the cost. The paper illustrates this idea in different examples, including $\mathcal{H}_{\infty}$ control and optimal control of coupled oscillators.
description: 6 pages, 4 figures
Boosting Plastic Packaging Recyclability: Setting the Right Standards
Creators: name: Ferguson, Nicholas
name: Baillargeon, Laure
name: Cottin, Valentin
name: Colard, Vincent
name: Aliaga, Cesar
name: Vera-Duran, Maria
name: Wood, Sultan
Publisher: name: Zenodo
Year: 2025
Subjects: standards
standardisation
plastic
packaging
European Standardisation

description: On 27 April 2023, HSbooster.eu project organised a webinar titled "Boosting Plastic Packaging Recyclability: Setting the Right Standards", focusing on the interplay between regulation, standardisation, research, and innovation and how these in unity can boost plastic packaging recyclability in Europe.

The webinar was started by HSbooster.eu Coordinator Nicholas Ferguson, who provided an overview of the project and our role in the European standardisation initiative. Followed by the European Commission and the European Technical Committee for Standardisation of Packaging, which talked about upcoming regulations, standards, and opportunities. The second session was the presentation of the European Horizon Projects, such as CIMPA, MERLIN, and upPE-T, which provided examples of their work with recycling plastic packaging and research and innovation projects and how projects can learn more about how to get engaged via HSbooster.eu. The final session involves panellists discussing the interplay between regulation, standardisation, research, and innovation.

Discover the exciting insights from our webinar by accessing the recording and presentations through this link. Simply click here to gain access and expand your knowledge on the topic. Don't miss out on this valuable resource!
Wilson loops: From four-dimensional SYM to two-dimensional YM
Creators: name: Drukker, Nadav
name: Giombi, Simone
name: Ricci, Riccardo
name: Trancanelli, Diego
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: In this note we study supersymmetric Wilson loops restricted to an S^2 submanifold of four-dimensional space in N=4 super Yang-Mills. We provide evidence from both perturbation theory and the AdS dual that those loops are equal to the analogous observables in two-dimensional Yang-Mills on S^2 (excluding non-perturbative contributions). This relates a subsector of N=4 SYM to a low-dimensional soluble model and also suggests that this subsector of N =4 SYM is invariant under area preserving diffeomorphisms.
description: 9 pages, LaTeX
Exotic Kondo-hole band resistivity and magnetoresistance of Ce$_{1-x}$La$_{x}$Os$_4$Sb$_{12}$ alloys
Creators: name: Rotundu, C. R.
name: Andraka, B.
name: Schlottmann, P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Electrical resistivity measurements of non-magnetic single-crystalline Ce$_{1-x}$La$_x$Os$_4$Sb$_{12}$ alloys, $x=0.02$ and 0.1, are reported for temperatures down to 20 mK and magnetic fields up to 18 T. At the lowest temperatures, the resistivity of Ce$_{0.98}$La$_{0.02}$Os$_4$Sb$_{12}$ has a Fermi-liquid-like temperature variation $ρ=ρ_0+A T^2$, but with negative $A$ in small fields. The resistivity has an unusually strong magnetic field dependence for a paramagnetic metal. The 20 mK resistivity increases by 75% between H=0 and 4 T and then decreases by 65% between 4 T and 18 T. Similarly, the $A$ coefficient increases with the field from -77 to 29$ μΩ$cmK$^{-2}$ between H=0 and 7 T and then decreases to 18$ μΩ$cmK$^{-2}$ for 18 T. This nontrivial temperature and field variation is attributed to the existence of a very narrow Kondo-hole band in the hybridization gap, which pins the Fermi energy. Due to disorder the Kondo-hole band has localized states close to the band edges. The resistivity for $x=0.1$ has a qualitatively similar behavior to that of $x=0.02$, but with a larger Kondo-hole band.
Radiative decays with light scalar mesons and singlet-octet mixing in ChPT
Creators: name: Ivashyn, S. A.
name: Korchin, A. Yu.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study different types of radiative decays involving f0(980) and a0(980) mesons within a unified ChPT-based approach at one-loop level. Light scalar resonances which are seen in pi pi, pi eta, K K-bar channels of phi(1020) radiative decays and in J/psi decays are responsible for key questions of low-energy dynamics in the strong interaction sector, and decays phi(1020) -> gamma a0(980), phi(1020) -> gamma f0(980), a0(980) -> gamma gamma, f0(980) -> gamma gamma are of interest for current experimental programs in Juelich, Frascati and Novosibirsk. From theoretical point of view it is important to verify whether light scalar mesons are members of some flavor octet or nonet. We find a value of mixing angle dictated by consistency with experiment and coupling structures of ChPT Lagrangian. Decay widths f0(980)/a0(980) -> gamma rho(770)/omega(782), which are not studied experimentally yet, are predicted. We also obtain several relations between widths, which hold independently of coupling constants and represent a fingerprint of the model.
description: 18 pages, 8 figures; misprints in text and tables corrected, discussion extended, references added; version accepted for publication in Eur.Phys.J. C
VISIR/VLT mid-infrared imaging of Seyfert nuclei: Nuclear dust emission and the Seyfert-2 dichotomy
Creators: name: Haas, Martin
name: Siebenmorgen, Ralf
name: Pantin, Eric
name: Horst, Hannes
name: Smette, Alain
name: Kaufl, Hans-Ulrich
name: Lagage, Pierre-Olivier
name: Chini, Rolf
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Half of the Seyfert-2 galaxies escaped detection of broad lines in their polarised spectra observed so far. Some authors have suspected that these non-HBLRs contain real Sy2 nuclei without intrinsic broad line region hidden behind a dust torus. If this were true, then their nuclear structure would fundamentally differ from that of Sy2s with polarised broad lines: in particular, they would not be explained by orientation-based AGN unification. Further arguments for two physically different Sy2 populations have been derived from the warm and cool IRAS F25/F60 ratios. These ratios, however, refer to the entire host galaxies and are unsuitable to conclusively establish the absence of a nuclear dust torus. Instead, a study of the Seyfert-2 dichotomy should be performed on the basis of nuclear properties only. Here we present the first comparison between [OIII] 5007A and mid-infrared imaging at matching spatial resolution. Exploring the Seyfert-2 dichotomy we find that the distributions of nuclear mid-infrared/[OIII] luminosity ratios are indistinguishable for Sy1s and Sy2s with and without detected polarised broad lines and irrespective of having warm or cool IRAS F25/F60 ratios. We find no evidence for the existence of a population of real Sy2s with a deficit of nuclear dust emission. Our results suggest 1) that all Seyfert nuclei possess the same physical structure including the putative dust torus and 2) that the cool IRAS colours are caused by a low contrast of AGN to host galaxy. Then the Seyfert-2 dichotomy is explained in part by unification of non-HBLRs with narrow-line Sy1s and to a larger rate by observational biases caused by a low AGN/host contrast and/or an unfavourable scattering geometry.
description: 11 pages, 6 figures, accepted by A&A
Free energy and extension of a semiflexible polymer in cylindrical confining geometries
Creators: name: Yang, Yingzi
name: Burkhardt, Theodore W.
name: Gompper, Gerhard
Publisher: name: arXiv
Year: 2007
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We consider a long, semiflexible polymer, with persistence length $P$ and contour length $L$, fluctuating in a narrow cylindrical channel of diameter $D$. In the regime $D\ll P\ll L$ the free energy of confinement $ΔF$ and the length of the channel $R_\parallel$ occupied by the polymer are given by Odijk's relations $ΔF/R_\parallel=A_\circ k_BTP^{-1/3}D^{-2/3}$ and $R_\parallel=L[1-α_\circ(D/P)^{2/3}]$, where $A_\circ$ and $α_\circ$ are dimensionless amplitudes. Using a simulation algorithm inspired by PERM (Pruned Enriched Rosenbluth Method), which yields results for very long polymers, we determine $A_\circ$ and $α_\circ$ and the analogous amplitudes for a channel with a rectangular cross section. For a semiflexible polymer confined to the surface of a cylinder, the corresponding amplitudes are derived with an exact analytic approach. The results are relevant for interpreting experiments on biopolymers in microchannels or microfluidic devices.
description: 15 pages without figures, 5 figures
Electric Polarization Induced by a Proper Helical Magnetic Ordering in a Delafossite Multiferroic CuFe1-xAlxO2
Creators: name: Nakajima, T.
name: Mitsuda, S.
name: Kanetsuki, S.
name: Tanaka, K.
name: Fujii, K.
name: Terada, N.
name: Soda, M.
name: Matsuura, M.
name: Hirota, K.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Multiferroic CuFe1-xAlxO2 (x=0.02) exhibits a ferroelectric ordering accompanied by a proper helical magnetic ordering below T=7K under zero magnetic field. By polarized neutron diffraction and pyroelectric measurements, we have revealed a one-to-one correspondence between the spin helicity and the direction of the spontaneous electric polarization. This result indicates that the spin helicity of the proper helical magnetic ordering is essential for the ferroelectricity in CuFe1-xAlxO2. The induction of the electric polarization by the proper helical magnetic ordering is, however, cannot be explained by the Katsura-Nagaosa-Balatsky model, which successfully explains the ferroelectricity in the recently explored ferroelectric helimagnets, such as TbMnO3. We thus conclude that CuFe1-xAlxO2 is a new class of magnetic ferroelectrics.
description: 4 pages, 4 figures
Determination of the Mott insulating transition by the multi-reference density functional theory
Creators: name: Kusakabe, K.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: It is shown that a momentum-boost technique applied to the extended Kohn-Sham scheme enables the computational determination of the Mott insulating transition. Self-consistent solutions are given for correlated electron systems by the first-principles calculation defined by the multi-reference density functional theory, in which the effective short-range interaction can be determined by the fluctuation reference method. An extension of the Harriman construction is made for the twisted boundary condition in order to define the momentum-boost technique in the first-principles manner. For an effectively half-filled-band system, the momentum-boost method tells that the period of a metallic ground state by the LDA calculation is shortened to the least period of the insulating phase, indicating occurrence of the Mott insulating transition.
description: 5 pages, 1 figure, to appear in J. Phys. Condens. Matter
The dynamics of the early universe and the initial conditions for inflation in a model with radiation and a Chaplygin gas
Creators: name: Monerat, G. A.
name: Oliveira-Neto, G.
name: Silva, E. V. Corrêa
name: Filho, L. G. Ferreira
name: Romildo, P.
name: Fabris, J. C.
name: Fracalossi, R.
name: Alvarenga, F. G.
name: Gonçalves, S. V. B.
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The modeling of the early universe is done through the quantization of a Friedmann-Robertson-Walker model with positive curvature. The material content consists of two fluids: radiation and Chaplygin gas. The quantization of these models is made by following the Wheeler and DeWitt's prescriptions. Using the Schutz formalism, the time notion is recovered and the Wheeler-DeWitt equation transforms into a time dependent Schrödinger equation, which rules the dynamics of the early universe, under the action of an effective potential $V_{ef}$. Using a finite differences method and the Crank-Nicholson scheme, in a code implemented in the program OCTAVE, we solve the corresponding time dependent Schrödinger equation and obtain the time evolution of a initial wave packet. This wave packet satisfies appropriate boundary conditions. The calculation of the tunneling probabilities shows that the universe may emerge from the Planck era to an inflationary phase. It also shows that, the tunneling probability is a function of the mean energy of the initial wave packet and of two parameters related to the Chaplygin gas. We also show a comparison between these results and those obtained by the WKB approximation.
description: Revtex file with 12 pages and 6 PS figures
A self-consistent first-principles calculation scheme for correlated electron systems
Creators: name: Kusakabe, Koichi
name: Suzuki, Naoshi
name: Yamanaka, Shusuke
name: Yamaguchi, Kizashi
Publisher: name: arXiv
Year: 2007
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: A self-consistent calculation scheme for correlated electron systems is created based on the density-functional theory (DFT). Our scheme is a multi-reference DFT (MR-DFT) calculation in which the electron charge density is reproduced by an auxiliary interacting Fermion system. A short-range Hubbard-type interaction is introduced by a rigorous manner with a residual term for the exchange-correlation energy. The Hubbard term is determined uniquely by referencing the density fluctuation at a selected localized orbital. This strategy to obtain an extension of the Kohn-Sham scheme provides a self-consistent electronic structure calculation for the materials design. Introducing an approximation for the residual exchange-correlation energy functional, we have the LDA+U energy functional. Practical self-consistent calculations are exemplified by simulations of Hydrogen systems, i.e. a molecule and a periodic one-dimensional array, which is a proof of existence of the interaction strength U as a continuous function of the local fluctuation and structural parameters of the system.
description: 23 pages, 8 figures, to appear in J. Phys. Condens. Matter
Collider signals in unparticle physics
Creators: name: Cheung, Kingman
name: Keung, Wai-Yee
name: Yuan, Tzu-Chiang
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: Phenomenology of the notion of an unparticle U, recently perceived by Georgi, to describe a scale invariant sector with a non-trivial infrared fixed point at a higher energy scale is explored in details. Behaving like a collection of d_U (the scale dimension of the unparticle operator O_U) invisible massless particles, this unparticle can be unveiled by measurements of various energy distributions for the processes Z to fermion pair + U and e-e+ to gamma U at e-e+ colliders, as well as mono-jet production at hadron colliders. We also study the propagator effects of the unparticle through the Drell-Yan tree level process and the one-loop muon anomaly.
description: 4 pages including 4 figures
Now you see it, now you don't - the circumstellar disk in the GRO J1008--57 system
Creators: name: Coe, M. J.
name: Bird, A. J.
name: Hill, A. B.
name: McBride, V. A.
name: Schurch, M.
name: Galache, J.
name: Wilson, C. A.
name: Finger, M.
name: Buckley, D. A.
name: Romero-Colmenero, E.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Multiwavelength observations are reported here of the Be/X-ray binary pulsar system GRO J1008-57. Over ten years worth of data are gathered together to show that the periodic X-ray outbursts are dependant on both the binary motion and the size of the circumstellar disk. In the first instance an accurate orbital solution is determined from pulse periods, and in the second case the strength and shape of the Halpha emission line is shown to be a valuable indicator of disk size and its behaviour. Furthermore, the shape of the emission line permits a direct determination of the disk size which is in good agreement with theoretical estimates. A detailed study of the pulse period variations during outbursts determined the binary period to be 247.8, in good agreement with the period determined from the recurrence of the outbursts.
description: Accepted for publication in MNRAS
The Chemistry of Spinel Ferrite Nanoparticle Nucleation, Crystallization, and Growth
Creators: name: Andersen, Henrik L.
name: Granados-Miralles, Cecilia
name: Jensen, Kirsten M. O.
name: Saura-Muzquiz, Matilde
name: Christensen, Mogens
Publisher: name: arXiv
Year: 2024
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The nucleation, crystallization, and growth mechanisms of MnFe2O4, CoFe2O4, NiFe2O4, and ZnFe2O4 nanocrystallites prepared from coprecipitated transition metal (TM) hydroxide precursors treated at sub-, near-, and supercritical hydrothermal conditions have been studied by in situ X-ray total scattering (TS) with pair distribution function (PDF) analysis, and in situ synchrotron powder X-ray diffraction (PXRD) with Rietveld analysis. The in situ TS experiments were carried out on 0.6 M TM hydroxide precursors prepared from aqueous metal chloride solutions using 24.5% NH4OH as the precipitating base. The PDF analysis reveals equivalent nucleation processes for the four spinel ferrite compounds under the studied hydrothermal conditions, where the TMs form edge-sharing octahedrally coordinated hydroxide units (monomers/dimers and in some cases trimers) in the aqueous precursor, which upon hydrothermal treatment nucleate through linking by tetrahedrally coordinated TMs. The in situ PXRD experiments were carried out on 1.2 M TM hydroxide precursors prepared from aqueous metal nitrate solutions using 16 M NaOH as the precipitating base. The crystallization and growth of the nanocrystallites were found to progress via different processes depending on the specific TMs and synthesis temperatures. The PXRD data show that MnFe2O4 and CoFe2O4 nanocrystallites rapidly grow (typically <1 min) to equilibrium sizes of 20-25 nm and 10-12 nm, respectively, regardless of applied temperature in the 170-420 C range, indicating limited possibility of targeted size control. However, varying the reaction time (0-30 min) and temperature (150-400 C) allows different sizes to be obtained for NiFe2O4 (3-30 nm) and ZnFe2O4 (3-12 nm) nanocrystallites.
Cooperative Secondary Authorization Recycling
Creators: name: Wei, Qiang
name: Beznosov, Konstantin
name: Ripeanu, Matei
Publisher: name: Zenodo
Year: 2006
Subjects: Cooperative
CSAR
Secondary Authorization
Recycling

description: As distributed enterprise systems scale up and become increasingly complex their authorization infrastructures are facing new challenges. Conventional request-response authorization architectures become fragile and scale poorly to massive-scale enterprises. We describe a collaborative approach to address these problems. In our approach, each application in the enterprise system caches its previous-made authorizations at its secondary decision point (SDP). An SDP can not only resolve the local request in the future but also share their authorization ability with other SDPs. Our simulation results demonstrate that cooperative authorization recycling approach improves the availability of access control architectures.
Fluctuation-induced quantum friction in nanoscale water flows
Creators: name: Kavokine, Nikita
name: Bocquet, Marie-Laure
name: Bocquet, Lydéric
Publisher: name: arXiv
Year: 2021
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The flow of water in carbon nanochannels has defied understanding thus far, with accumulating experimental evidence for ultra-low friction, exceptionally high water flow rates, and curvature-dependent hydrodynamic slippage. These unique properties have raised considerable interest in carbon-based membranes for desalination, molecular sieving and energy harvesting. However, the mechanism of water-carbon friction remains unknown, with neither current theories, nor classical or ab initio molecular dynamics simulations providing satisfactory rationalisation for its singular behaviour. Here, we develop a quantum theory of the solid-liquid interface, which reveals a new contribution to friction, due to the coupling of charge fluctuations in the liquid to electronic excitations in the solid. We expect that this quantum friction, which is absent in Born-Oppenheimer molecular dynamics, is the dominant friction mechanism for water on carbon-based materials. As a key result, we demonstrate a dramatic difference in quantum friction between the water-graphene and water-graphite interface, due to the coupling of water Debye collective modes with a thermally excited plasmon specific to graphite. This suggests an explanation for the radius-dependent slippage of water in carbon nanotubes, in terms of the nanotubes' electronic excitations. Our findings open the way to quantum engineering of hydrodynamic flows through the confining wall electronic properties.
Hypersuccinct Trees -- New universal tree source codes for optimal compressed tree data structures and range minima
Creators: name: Munro, J. Ian
name: Nicholson, Patrick K.
name: Benkner, Louisa Seelbach
name: Wild, Sebastian
Publisher: name: arXiv
Year: 2021
Subjects: subject: Data Structures and Algorithms (cs.DS)
subject: Information Theory (cs.IT)
subject: FOS: Computer and information sciences

description: We present a new universal source code for distributions of unlabeled binary and ordinal trees that achieves optimal compression to within lower order terms for all tree sources covered by existing universal codes. At the same time, it supports answering many navigational queries on the compressed representation in constant time on the word-RAM; this is not known to be possible for any existing tree compression method. The resulting data structures, "hypersuccinct trees", hence combine the compression achieved by the best known universal codes with the operation support of the best succinct tree data structures. We apply hypersuccinct trees to obtain a universal compressed data structure for range-minimum queries. It has constant query time and the optimal worst-case space usage of $2n+o(n)$ bits, but the space drops to $1.736n + o(n)$ bits on average for random permutations of $n$ elements, and $2\lg\binom nr + o(n)$ for arrays with $r$ increasing runs, respectively. Both results are optimal; the former answers an open problem of Davoodi et al. (2014) and Golin et al. (2016). Compared to prior work on succinct data structures, we do not have to tailor our data structure to specific applications; hypersuccinct trees automatically adapt to the trees at hand. We show that they simultaneously achieve the optimal space usage to within lower order terms for a wide range of distributions over tree shapes, including: binary search trees (BSTs) generated by insertions in random order / Cartesian trees of random arrays, random fringe-balanced BSTs, binary trees with a given number of binary/unary/leaf nodes, random binary tries generated from memoryless sources, full binary trees, unary paths, as well as uniformly chosen weight-balanced BSTs, AVL trees, and left-leaning red-black trees.
description: part of ESA 2021
Neural network--featured timing systems for radiation detectors: performance evaluation based on bound analysis
Creators: name: Ai, Pengcheng
name: Deng, Zhi
name: Wang, Yi
name: Li, Linmao
Publisher: name: arXiv
Year: 2021
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: Waveform sampling systems are used pervasively in the design of front end electronics for radiation detection. The introduction of new feature extraction algorithms (eg. neural networks) to waveform sampling has the great potential to substantially improve the performance and enrich the capability. To analyze the limits of such algorithms and thus illuminate the direction of resolution optimization, in this paper we systematically simulate the detection procedure of contemporary radiation detectors with an emphasis on pulse timing. Neural networks and variants of constant fraction discrimination are studied in a wide range of analog channel frequency and noise level. Furthermore, we propose an estimation of multivariate Cramér Rao lower bound within the model using intrinsic-extrinsic parametrization and prior information. Two case studies (single photon detection and shashlik-type calorimeter) verify the reliability of the proposed method and show it works as a useful guideline when assessing the abilities of various feature extraction algorithms.
description: 25 pages, 13 figures. This is the Accepted Manuscript version of an article accepted for publication in Journal of Instrumentation. Neither SISSA Medialab Srl nor IOP Publishing Ltd is responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1088/1748-0221/16/09/P09019
Fallback Accretion Halted by R-process Heating in Neutron Star Mergers and Gamma-Ray Bursts
Creators: name: Ishizaki, Wataru
name: Kiuchi, Kenta
name: Ioka, Kunihito
name: Wanajo, Shinya
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The gravitational wave event GW170817 with a macronova/kilonova shows that a merger of two neutron stars ejects matter with radioactivity including $r$-process nucleosynthesis. A part of the ejecta inevitably falls back to the central object, possibly powering long-lasting activities of a short gamma-ray burst (sGRB), such as extended and plateau emissions. We investigate the fallback accretion with the $r$-process heating by performing one-dimensional hydrodynamic simulations and developing a semi-analytical model. We show that the usual fallback rate $dM/dt \propto t^{-5/3}$ is halted by the heating because pressure gradients accelerate ejecta beyond an escape velocity. The suppression is steeper than Chevalier's power-law model through Bondi accretion within a turn-around radius. The characteristic halting timescale is $\sim 10^5$--$10^9$ sec for the GW170817-like $r$-process heating, which is long enough to continue the long-lasting emission of sGRBs. The halting timescale is sensitive to the uncertainty of the $r$-process. Future observation of fallback halting could constrain the $r$-process heating on the year scale.
description: 22 pages, 15 figures
Towards Agile Security Assurance
Creators: name: Beznosov, Konstantin
Publisher: name: Zenodo
Year: 2006
Subjects: agile methods
eXtreme Programming
XP
security assurance
engineering secure software

description: Agile development methods are promising to become the next generation replacing waterfall development. They could eventually replace the plan-driven methodologies not only in pure software solutions in such benign domains as word processing and office automation but also in security-critical projects with both software and hardware parts developed or integrated together.  At the same time, the accepted practices for security assurance appear to go totally contrary to agile approaches. Can and how security assurance be adopted by agile developers? What needs to be done for the adoption to happen? This talk makes a first step toward answering these questions in a pursuit for agile security assurance. It first explains what computer and software security is and why it is hard. Then, it re-examines the conventional practices of security assurance to find out how well they suite agile development methodologies. It classifies security assurance methods and techniques with regards to their clash with agile development. For those in conflict, ways of alleviating it are suggested.
title: Процессуальные вопросы применения реституции
title: Procedural Issues in the Application of Restitution
Creators: name: Довгань, Ксения Евгеньевна
name: Коваленко, Наталья Евгеньевна
name: Угрюмов, Рустам Шарканович
Publisher: name: Издательский центр СурГУ
Year: 2021

description: Статья посвящена проблемам, возникающим в процессе применения последствий недействительности сделки (реституции). Пристальное внимание уделяется вопросам правовой природы реституции и рассмотрению данного явления с точки зрения самостоятельного требования. Изучается судебная практика, в том числе рекомендации высших судебных инстанций по практике применения реституции в гражданских правоотношениях. На основе судебной практики по гражданским делам анализируется практика применения судами норм гражданского законодательства в контексте определения последствий недействительности сделки. Институт реституции рассматривается с точки зрения гражданско-правового законодательства, отмечается такой его признак, как публичность, существующий еще с советских времен. Также исследуется правовая доктрина, которую необходимо соотнести с возникающими в судебной практике казусами. Неопределенность как способ правового регулирования, используемый законодателем, создает трудности в защите прав и свобод граждан и юридических лиц, а также в правоприменительной практике.
description: The article is devoted to the problems emerging in the process of application of the consequences of the transaction invalidity (restitution). Close attention is paid to the issues of legal nature of restitution and consideration of such phenomenon according to the independent claim. Judicial practice as well as the supreme judicial authorities’ recommendations on practice of the application of restitution in civil legal relations are analyzed. Based on the judicial practice on civil cases, the analysis of practice of application of rules of civil legislation by courts is carried out in the context of defining the consequences of the transaction invalidity. The article analyzes the institute of restitution in terms of civil legislation and determines such a feature as publicity existed since the Soviet period. Legal doctrine that has to be correlated with emerging exceptional cases in the judicial practice is also analyzed. Such method of legal regulation as uncertainty used by legislator creates difficulties in the protection of rights and freedoms of citizens and legal entities, as well as in law enforcement practice.
A Blueprint for the Milky Way's Stellar Populations. III. Spatial Distributions and Population Fractions of Local Halo Stars
Creators: name: An, Deokkeun
name: Beers, Timothy C.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We analyze the observed spatial, chemical and dynamical distributions of local metal-poor stars, based on photometrically derived metallicity and distance estimates along with proper motions from the Gaia mission. Along the Galactic prime meridian, we identify stellar populations with distinct properties in the metallicity versus rotational velocity space, including Gaia Sausage/Enceladus (GSE), the metal-weak thick disk (MWTD), and the Splash (sometimes referred to as the "in situ" halo). We model the observed phase-space distributions using Gaussian mixtures and refine their positions and fractional contributions as a function of distances from the Galactic plane ($|Z|$) and the Galactic center ($R_{\rm GC}$), providing a global perspective of the major stellar populations in the local halo. Within the sample volume ($|Z|<6$ kpc), stars associated with GSE exhibit a larger proportion of metal-poor stars at greater $R_{\rm GC}$ ($Δ\langle{\rm[Fe/H]}\rangle /ΔR_{\rm GC} =-0.05\pm0.02$ dex kpc$^{-1}$). This observed trend, along with a mild anticorrelation of the mean rotational velocity with metallicity ($Δ\langle v_ϕ\rangle / Δ\langle{\rm[Fe/H]} \rangle \sim -10$ km s$^{-1}$ dex$^{-1}$), implies that more metal-rich stars in the inner region of the GSE progenitor were gradually stripped away, while the prograde orbit of the merger at infall became radialized by dynamical friction. The metal-rich GSE stars are causally disconnected from the Splash structure, whose stars are mostly found on prograde orbits ($>94\%$) and exhibit a more centrally concentrated distribution than GSE. The MWTD exhibits a similar spatial distribution to the Splash, suggesting earlier dynamical heating of stars in the primordial disk of the Milky Way, possibly before the GSE merger.
description: 32 pages, 14 figures, 3 tables, accepted for publication in the Astrophysical Journal after minor revision
Reservoir Computing based on Mutually Injected Phase Modulated Semiconductor Lasers as a monolithic integrated hardware accelerator
Creators: name: Sozos, Kostas
name: Mesaritakis, Charis
name: Bogris, Adonis
Publisher: name: arXiv
Year: 2021
Subjects: subject: Emerging Technologies (cs.ET)
subject: Signal Processing (eess.SP)
subject: FOS: Computer and information sciences
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: In this paper we propose and numerically study a neuromorphic computing scheme that applies delay-based reservoir computing in a laser system consisting of two mutually coupled phase modulated lasers. The scheme can be monolithic integrated in a straightforward manner and alleviates the need for external optical injection, as the data can be directly applied on the on-chip phase modulator placed between the two lasers. The scheme also offers the benefit of increasing the nodes compared to a reservoir computing system using either one laser under feedback or laser under feedback and optical injection. Numerical simulations assess the performance of the integrated reservoir computing system in dispersion compensation tasks in short-reach optical communication systems. We numerically demonstrate that the proposed platform can recover severely distorted 25 Gbaud PAM-4 signals for transmission distances exceeding 50km and outperform other competing delay-based reservoir computing systems relying on optical feedback. The proposed scheme, thanks to its compactness and simplicity, can play the role of a monolithic integrated hardware accelerator in a wide range of application requiring high speed real time processing.
Evaluating the grinding process of granitic rocks using the physico-mechanical and mineralogical properties
Creators: name: Sair KAHRAMAN
Publisher: name: Metallurgy and Materials Science Research Institute Chulalongkorn University
Year: 2019
Subjects: Grinding
Mean particle size
Granites
Physico-mechanical properties
Abrasive mineral content

description: Journal of Metals Materials and Minerals, 29, 2, 51-57
Working_from_Home_during_the_COVID_19.pdf
Creators: name: Rahman, Kazi Turin
name: Md. Zahir Uddin Arif
Publisher: name: figshare
Year: 2021
Subjects: subject: 150307 Innovation and Technology Management
subject: FOS: Economics and business

description: Purpose- This study has investigated how professionals are collaborating online working from home (WFH) during COVID-19 pandemic in Bangladesh. Various aspects of this shift in working culture have been examined like employee satisfaction levels, challenges related to telecommuting and perceived productivity of working remotely during the COVID-19 outbreak situation.
Design/methodology/approach- This study has employed an exploratory research design. The study has obtained secondary data from various articles published in journals and conference proceedings, books, news media, website etc. and primary data via an online survey using a set of a semi-structured questionnaire. Convenience sampling technique has been used to choose a sample of professionals working from home (WFH) during the COVID-19 pandemic (n=100). Both sample selection and survey administration have been done through social media messaging services owing to strict lockdown measures.
Findings- All in all, the results have shown that most of the participants are fairly satisfied with working from home (WFH) during the COVID19 pandemic. Work flexibility is the main factor contributing to this satisfaction. Moreover, the majority of the respondents have cited internet connectivity and maintaining the regular schedule as the biggest challenges of telecommuting. Finally, most of the participants have felt that they have been getting more work done at home as compared to onsite locations.
Originality/value- This is one of the few studies to focus on working from home (WFH) during the COVID-19 pandemic. The findings have vital implications for working professionals, organizations and HR policymakers.
title: AI3SD AI in Materials Discovery Workshop Report 2019
Creators: name: Knight, Nicola
name: Bird, Colin Leonard
Publisher: name: University of Southampton
Year: 2019
Subjects: subject: AI3SD, Workshop Report, materials, AI, Artificial intelligence, Machine Learning

description: This workshop was a half-day event hosted at the University of Southampton, with the focus of the event being the use of AI in materials discovery and innovation. The event was structured with an introductory talk followed by 5 keynote sessions from experts in the materials field. These talks were separated by a coffee break giving participants time to network. This workshop is one in a series of events hosted by the AI3SD Network designed to provide a platform for discussion, innovation and collaboration for using AI in scientific discovery. The events bring together researchers and experts to disseminate knowledge and allow new connections to flourish.
Issues in the Security Architecture of the Computerized Patient Record Enterprise
Creators: name: Beznosov, Konstantin
Publisher: name: Zenodo
Year: 2006
Subjects: security architecture
CPR
computerized patient record
engineering security mechanisms

description: We discuss issues in CPR enterprise security architecture. The main goal is to provide a security environment where a user will be viewed the same across all enterprise systems, and access control decisions will be consistent across all components of the CPR enterprise.
The Secondary and Approximate Authorization Model and its Application to BellLaPadula Policies
Creators: name: Beznosov, Konstantin
Publisher: name: Zenodo
Year: 2006
Subjects: SAAM
JAMES
access control
Bell-LaPadulla
BLP
access control models and languages

description: The request-response paradigm used for access control solutions commonly leads to point-to-point (PTP) architectures, with security enforcement logic obtaining decisions from authorization servers through remote procedure calls. In massive-scale and complex enterprises, PTP authorization architectures result in fragile and inefficient solutions. They also fail to exploit virtually free CPU resources and network bandwidth. This talk introduces a three-fold approach to improving availability and performance of authorization solutions: employing publish-subscribe technologies, *actively* recycling authorizations, and flooding PEPs with speculatively precomputed *junk* authorizations.  After introducing the approach, the talk describes in detail the active authorization recycling part. Specifically, it defines the secondary and approximate authorization model (SAAM). In SAAM, approximate authorization responses are inferred from cached primary responses, and therefore provide an alternative source of access control decisions in the event that the authorization server is unavailable or slow. The ability to compute approximate authorizations improves the reliability and performance of access control sub-systems and ultimately the application systems themselves. The operation of a system that employs SAAM depends on the type of access control policy it implements. We propose and analyze algorithms for computing secondary authorizations in the case of policies based on the Bell-LaPadula model. In this context, we define a dominance graph, and describe its construction and usage for generating secondary responses to authorization requests. Preliminary results of evaluating SAAM-BLP algorithms demonstrate a 15% increase in the number of authorization requests that can be served without consulting access control policies.
On the self-adjointness of certain reduced Laplace-Beltrami operators
Creators: name: Feher, L.
name: Pusztai, B. G.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mathematical Physics (math-ph)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The self-adjointness of the reduced Hamiltonian operators arising from the Laplace-Beltrami operator of a complete Riemannian manifold through quantum Hamiltonian reduction based on a compact isometry group is studied. A simple sufficient condition is provided that guarantees the inheritance of essential self-adjointness onto a certain class of restricted operators and allows us to conclude the self-adjointness of the reduced Laplace-Beltrami operators in a concise way. As a consequence, the self-adjointness of spin Calogero-Sutherland type reductions of `free' Hamiltonians under polar actions of compact Lie groups follows immediately.
description: 9 pages, minor changes, updated references in v2