cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Degenerating families of dendrograms
Creators: name: Bradley, Patrick Erik
Publisher: name: arXiv
Year: 2007
Subjects: subject: Machine Learning (stat.ML)
subject: FOS: Computer and information sciences

description: Dendrograms used in data analysis are ultrametric spaces, hence objects of nonarchimedean geometry. It is known that there exist $p$-adic representation of dendrograms. Completed by a point at infinity, they can be viewed as subtrees of the Bruhat-Tits tree associated to the $p$-adic projective line. The implications are that certain moduli spaces known in algebraic geometry are $p$-adic parameter spaces of (families of) dendrograms, and stochastic classification can also be handled within this framework. At the end, we calculate the topology of the hidden part of a dendrogram.
description: 13 pages, 8 figures
Lie fields revisited
Creators: name: Morgan, Peter
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: A class of interacting classical random fields is constructed using deformed *-algebras of creation and annihilation operators. The fields constructed are classical random field versions of "Lie fields". A vacuum vector is used to construct linear forms over the algebras, which are conjectured to be states over the algebras. Assuming this conjecture is true, the fields constructed are "quantum random fields" in the sense that they have Poincare invariant vacua with a fluctuation scale determined by Planck's constant. A nonlocal particle interpretation of the formalism is shown to be the same as a particle interpretation of a quantum field theory.
description: 13 pages; to appear in J.Math.Phys
Diquark Representations for Singly Heavy Baryons with Light Staggered Quarks
Creators: name: Gottlieb, Steven
name: Na, Heechang
name: Nagata, Kazuhiro
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: FOS: Physical sciences

description: In the staggered fermion formulation of lattice QCD, we construct diquark operators which are to be embedded in singly heavy baryons. The group theoretical connections between continuum and lattice staggered diquark representations are established.
description: v1, 13 pages with title "Staggered Diquarks for Singly Heavy Baryons"; v2, 4 pages in revtex, changed the title to be more specific
Witness electron beam injection using an active plasma lens for a proton beam-driven plasma wakefield accelerator
Creators: name: Kim, S. -Y.
name: Moon, K.
name: Chung, M.
name: Sjobak, K. N.
name: Adli, E.
name: Doebert, S.
name: Dayyani, M.
name: Yoon, E. S.
name: Nam, I.
name: Hahn, G.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Accelerator Physics (physics.acc-ph)
subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: An active plasma lens focuses the beam in both the horizontal and vertical planes simultaneously using a magnetic field generated by a discharge current through the plasma. A beam size of 5--10 $μ$m can be achieved within a short distance using a focusing gradient on the order of 100 T/m. The active plasma lens is therefore an attractive element for plasma wakefield acceleration, because an ultra-small size of the witness electron beam is required for injection into the plasma wakefield to minimize emittance growth and to enhance the capturing efficiency. When the drive beam and witness electron beam co-propagate through the active plasma lens, interactions between the drive and witness beams, and the plasma must be considered. In this paper, through particle-in-cell simulations, we discuss the possibility of using an active plasma lens for the final focusing of the electron beam for the AWAKE RUN 2 experiments. It is confirmed that the amplitude of the plasma wakefield excited by proton bunches remains the same even after propagation through the active plasma lens. The emittance of the witness electron beam increases rapidly in the plasma density ramp regions of the lens. Nevertheless, when the witness electron beam has a charge of 100 pC, emittance of 10 mm mrad, and bunch length of 60 $μ$m, its emittance growth is not significant along the active plasma lens. For small emittance, such as 2 mm mrad, the emittance growth is found to be strongly dependent on the RMS beam size, plasma density, and multiple Coulomb scattering.
Bounds on new physics from B_s mixing
Creators: name: Nierste, Ulrich
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: I summarize the observables constraining the B_s-B_s-bar mixing complex and present a new calculation of the element Gamma_{12}^s of the decay matrix. Gamma_{12}^s enters the prediction of the width difference Delta Gamma_s, for which we obtain Delta Gamma_s^SM = 0.088 +/- 0.017 ps^(-1), if no new physics enters B_s-B_s-bar mixing. Applying our formulae to Tevatron data we find a deviation of the B_s-B_s-bar mixing phase phi_s from its Standard Model value by 2 standard deviations. I stress that present data do not give any information on the sign of Delta Gamma_s.
description: Talk at "CTP Symposium On Supersymmetry At LHC: Theoretical And Experimental Prospectives", 11-14 Mar 2007, Cairo, Egypt
Orthogonal complex structures on domains in R^4
Creators: name: Salamon, Simon
name: Viaclovsky, Jeff
Publisher: name: arXiv
Year: 2007
Subjects: subject: Differential Geometry (math.DG)
subject: Algebraic Geometry (math.AG)
subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: An orthogonal complex structure on a domain in R^4 is a complex structure which is integrable and is compatible with the Euclidean metric. This gives rise to a first order system of partial differential equations which is conformally invariant. We prove two Liouville-type uniqueness theorems for solutions of this system, and use these to give an alternative proof of the classification of compact locally conformally flat Hermitian surfaces first proved by Pontecorvo. We also give a classification of non-degenerate quadrics in CP^3 under the action of the conformal group. Using this classification, we show that generic quadrics give rise to orthogonal complex structures defined on the complement of unknotted solid tori which are smoothly embedded in R^4.
description: 42 pages. Version 2 contains several improvements and simplifications throughout. Material from the first version on more general branched coverings has been removed in order to make the article more focused, and will appear elsewhere
Dinámica de la desconfiguración y la reconstrucción de la semiósfera de La ciudad y los perros
Creators: name: Aguila, Jesús Miguel Delgado Del
Publisher: name: figshare
Year: 2021
Subjects: Literature

description: Delgado Del Aguila, Jesús Miguel (2019). «Dinámica de la desconfiguración y la reconstrucción de la semiósfera de La ciudad y los perros», en: Cuadernos del Hipogrifo. Revista Semestral de Literatura Hispanoamericana y Comparada. Roma, Italia. N.° 11, pp. 52-73. Disponible en http://www.revistaelhipogrifo.com/wp-content/uploads/2019/08/52-73.pdf
Quantum Monte Carlo study of ring-shaped polariton parametric luminescence in a semiconductor microcavity
Creators: name: Verger, Arnaud
name: Carusotto, Iacopo
name: Ciuti, Cristiano
Publisher: name: arXiv
Year: 2007
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: We present a quantum Monte Carlo study of the quantum correlations in the parametric luminescence from semiconductor microcavities in the strong exciton-photon coupling regime. As already demonstrated in recent experiments, a ring-shaped emission is obtained by applying two identical pump beams with opposite in-plane wavevectors, providing symmetrical signal and idler beams with opposite in-plane wavevectors on the ring. We study the squeezing of the signal-idler difference noise across the parametric instability threshold, accounting for the radiative and non-radiative losses, multiple scattering and static disorder. We compare the results of the complete multimode Monte Carlo simulations with a simplified linearized quantum Langevin analytical model.
Inflation from inhomogeneous polarized Gowdy model
Creators: name: Olmedo, Javier
Publisher: name: arXiv
Year: 2021
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study polarized Gowdy cosmologies on the three torus coupled to a massive scalar field. The phase space of the model admits a simple splitting between homogeneous and inhomogeneous sectors after a suitable gauge fixing. The presence of the mass term of the scalar field breaks the linearity of the equations of motion of the inhomogeneous fields. We discuss regimes of physical interest in which we recover a linear dynamics of these nonperturbative inhomogeneities, despite the metric is fully inhomogeneous at early times. We expand the inhomogeneous fields in Fourier modes and express them at all times as linear combinations of a basis of orthonormal complex solutions to the equations of motion, with coefficients that turn out to be an infinite collection of constants of motion. We argue that the resulting model can describe a nonperturbative inhomogeneous early universe dominated by the kinetic energy of an inflaton at early times that can eventually reach a slow-roll regime with a nearly exponential expansion at late times that isotropices and homogenizes the geometry.
description: 26 pages, match with published version, typos corrected
Topology by Dissipation: Majorana Bosons in Metastable Quadratic Markovian Dynamics
Creators: name: Flynn, Vincent P.
name: Cobanera, Emilio
name: Viola, Lorenza
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: Majorana bosons, that is, tight bosonic analogs of the Majorana fermionic quasiparticles of condensed matter physics, are forbidden for gapped free bosonic matter within a standard Hamiltonian scenario. We show how the interplay between dynamical metastability and nontrivial bulk topology makes their emergence possible in noninteracting bosonic chains undergoing Markovian dissipation. This leads to a distinctive form of topological metastability, whereby a conserved Majorana boson localized on one edge is paired, in general, with a symmetry generator localized on the opposite edge. We argue that Majorana bosons are robust against disorder and identifiable by signatures in the zero-frequency steady-state power spectrum. Our results suggest that symmetry-protected topological phases for free bosons may arise in transient metastable regimes, which persist over practical timescales.
description: 6 pages, 4 figures
Mumford dendrograms
Creators: name: Bradley, Patrick Erik
Publisher: name: arXiv
Year: 2007
Subjects: subject: Discrete Mathematics (cs.DM)
subject: FOS: Computer and information sciences

description: An effective $p$-adic encoding of dendrograms is presented through an explicit embedding into the Bruhat-Tits tree for a $p$-adic number field. This field depends on the number of children of a vertex and is a finite extension of the field of $p$-adic numbers. It is shown that fixing $p$-adic representatives of the residue field allows a natural way of encoding strings by identifying a given alphabet with such representatives. A simple $p$-adic hierarchic classification algorithm is derived for $p$-adic numbers, and is applied to strings over finite alphabets. Examples of DNA coding are presented and discussed. Finally, new geometric and combinatorial invariants of time series of $p$-adic dendrograms are developped.
description: 16 pages, 7 figures; Incorporating Special Issue: Ultrametric and p-Adic Applications in Computer Science
Large Nongaussianity from Nonlocal Inflation
Creators: name: Barnaby, N.
name: Cline, J. M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Astrophysics (astro-ph)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the possibility of obtaining large nongaussian signatures in the Cosmic Microwave Background in a general class of single-field nonlocal hill-top inflation models. We estimate the nonlinearity parameter f_{NL} which characterizes nongaussianity in such models and show that large nongaussianity is possible. For the recently proposed p-adic inflation model we find that f_{NL} ~ 120 when the string coupling is order unity. We show that large nongaussianity is also possible in a toy model with an action similar to those which arise in string field theory.
description: 27 pages, no figures. Added references and some clarifying remarks
Electron-hole contribution to the apparent s-d exchange interaction in III-V diluted magnetic semiconductors
Creators: name: Sliwa, C.
name: Dietl, T.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Spin splitting of photoelectrons in p-type and electrons in n-type III-V Mn-based diluted magnetic semiconductors is studied theoretically. It is demonstrated that the unusual sign and magnitude of the apparent s-d exchange integral reported for GaAs:Mn arises from exchange interactions between electrons and holes bound to Mn acceptors. This interaction dominates over the coupling between electrons and Mn spins, so far regarded as the main source of spin-dependent phenomena. A reduced magnitude of the apparent s-d exchange integral found in n-type materials is explained by the presence of repulsive Coulomb potentials at ionized Mn acceptors and a bottleneck effect.
description: 9 pages, 6 figures; in this version the value of the bound hole g-factor is corrected and cond-mat/0505126 is included as section VI
Quantisation of Hopping Magnetoresistance Prefactor in Strongly Correlated Two-Dimensional Electron Systems
Creators: name: Baenninger, Matthias
name: Ghosh, Arindam
name: Pepper, Michael
name: Beere, Harvey E.
name: Farrer, Ian
name: Atkinson, Paula
name: Ritchie, Dave A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: We report an universal behaviour of hopping transport in strongly interacting mesoscopic two-dimensional electron systems (2DES). In a certain window of background disorder, the resistivity at low perpendicular magnetic fields follows the expected relation $ρ(B_\perp) = ρ_{\rm{B}}\exp(αB_\perp^2)$. The prefactor $ρ_{\rm{B}}$ decreases exponentially with increasing electron density but saturates to a finite value at higher densities. Strikingly, this value is found to be universal when expressed in terms of absolute resistance and and shows quantisation at $R_{\rm{B}}\approx h/e^2$ and $R_{\rm{B}}\approx 1/2$ $ h/e^2$. We suggest a strongly correlated electronic phase as a possible explanation.
description: 5 pages, 3 figures, Proceedings of EP2DS 17, Reference added
Generation of strongly chaotic beats
Creators: name: Sliwa, I.
name: Szlachetka, P.
name: Grygiel, K.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: The letter proposes a procedure for generation of strongly chaotic beats that have been hardly obtainable hitherto. The beats are generated in a nonlinear optical system governing second-harmonic generation of light. The proposition is based on the concept of an optical coupler but can be easily adopted to other nonlinear systems and Chua's circuits.
description: 10 pages, 4 figures, accepted for publication in Int.J.Bif.Chaos
QuantumCumulants.jl: A Julia framework for generalized mean-field equations in open quantum systems
Creators: name: Plankensteiner, David
name: Hotter, Christoph
name: Ritsch, Helmut
Publisher: name: arXiv
Year: 2021
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: A full quantum mechanical treatment of open quantum systems via a Master equation is often limited by the size of the underlying Hilbert space. As an alternative, the dynamics can also be formulated in terms of systems of coupled differential equations for operators in the Heisenberg picture. This typically leads to an infinite hierarchy of equations for products of operators. A well-established approach to truncate this infinite set at the level of expectation values is to neglect quantum correlations of high order. This is systematically realized with a so-called cumulant expansion, which decomposes expectation values of operator products into products of a given lower order, leading to a closed set of equations. Here we present an open-source framework that fully automizes this approach: first, the equations of motion of operators up to a desired order are derived symbolically using predefined canonical commutation relations. Next, the resulting equations for the expectation values are expanded employing the cumulant expansion approach, where moments up to a chosen order specified by the user are included. Finally, a numerical solution can be directly obtained from the symbolic equations. After reviewing the theory we present the framework and showcase its usefulness in a few example problems.
WhONet: Wheel Odometry Neural Network for Vehicular Localisation in GNSS-Deprived Environments
Creators: name: Onyekpe, Uche
name: Palade, Vasile
name: Herath, Anuradha
name: Kanarachos, Stratis
name: Fitzpatrick, Michael E.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Robotics (cs.RO)
subject: FOS: Computer and information sciences

description: In this paper, a deep learning approach is proposed to accurately position wheeled vehicles in Global Navigation Satellite Systems (GNSS) deprived environments. In the absence of GNSS signals, information on the speed of the wheels of a vehicle (or other robots alike), recorded from the wheel encoder, can be used to provide continuous positioning information for the vehicle, through the integration of the vehicle's linear velocity to displacement. However, the displacement estimation from the wheel speed measurements are characterised by uncertainties, which could be manifested as wheel slips or/and changes to the tyre size or pressure, from wet and muddy road drives or tyres wearing out. As such, we exploit recent advances in deep learning to propose the Wheel Odometry neural Network (WhONet) to learn the uncertainties in the wheel speed measurements needed for correction and accurate positioning. The performance of the proposed WhONet is first evaluated on several challenging driving scenarios, such as on roundabouts, sharp cornering, hard-brake and wet roads (drifts). WhONet's performance is then further and extensively evaluated on longer-term GNSS outage scenarios of 30s, 60s, 120s and 180s duration, respectively over a total distance of 493 km. The experimental results obtained show that the proposed method is able to accurately position the vehicle with up to 93% reduction in the positioning error of its original counterpart after any 180s of travel. WhONet's implementation can be found at https://github.com/onyekpeu/WhONet.
FX Asian Option Introduction and Valuation Practical Guide
Creators: name: Lee, David
Publisher: name: Zenodo
Year: 2020
Subjects: FX Asian option, FX option, FX European option, option valuation

description: An FX Asian option or Asian currency option is a special type of option contract where the payoff depends on the average of the underlying exchange rates over a certain period of time. The payoff is different from the case of a European option or American option, where the payoff of the option contract depends on the underlying FX rate at exercise date.
description: https://ia803406.us.archive.org/6/items/fx-asian-18/FxAsian-archive.pdf
Open Access eXchange (OAeX): a proposal for a sustainable crowd-funding model for academy/academic-led Open Scholarship
Creators: name: Hyland, Jack
name: Kouker, Alexander
name: Zaitsev, Dmitri
Publisher: name: Zenodo
Year: 2019
Subjects: Open access
Business model
Open educational resources
Crowdfunding
Public good
Value theory
Open science

description: This document describes the Open Access eXchange (OAeX) project, a proposal for an online marketplace that connects funders (HEIs, funding agencies, academic libraries, philanthropic entities etc.) and bidders (any public or private non-commercial entity seeking funding to realise their OA project) with the mutual objective of realising open-access (OA) projects (examples include OS software, institutional/central repositories, OA publishers, OA research tools, Open Educational Resources (OER) etc.) The novelty of OAeX rests therein that the service enables a competitive marketplace for OA-project initiatives. This approach contrasts, for example, with the Finnish Kotilava project where library-funders are asked to pay a fixed amount in support of an entire OA initiative, thus giving the market no role in quality control or an opportunity to regulate their level of funding and commitment. OAeX also diverges from coordinated initiatives such as IOI or SCOSS, where “the SCOSS board … [exclusively] evaluates applicants [bidders] rigorously based on [various] criteria” (The Global Sustainability Coalition for Open Science Services (SCOSS), no date). Libraria, on the other hand, works through an open-access publishing cooperative instead of using a market mechanism.
description: An earlier version of the OAeX Green Paper was presented at the IFLA Special Interest Group (SIG) on Library Publishing 2019 Midterm Meeting on Thursday February 28th – Friday March 1st 2019 at Dublin Business School, Dublin, Ireland.
Strong orientational effect of stretched aerogel on the 3He order parameter
Creators: name: Elbs, J.
name: Bunkov, Yu. M.
name: Collin, E.
name: Godfrin, H.
name: Volovik, G. E.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Adaptation and Self-Organizing Systems (nlin.AO)
subject: FOS: Physical sciences

description: Deformation of aerogel strongly modifies the orientation of the order parameter of superfluid 3He confined in aerogel. We used a radial squeezing of aerogel to keep the orbital angular momentum of the 3He Cooper pairs in the plane perpendicular to the magnetic field. We did not find strong evidence for a "polar" phase, with a nodal line along the equator of the Fermi surface, predicted to occur at large radial squeezing. Instead we observed 3He-A with a clear experimental evidence of the destruction of the long-range order by random anisotropy -- the Larkin-Imry-Ma effect. In 3He-B we observed and identified new modes of NMR, which are impossible to obtain in bulk 3He-B. One of these modes is characterized by a repulsive interaction between magnons, which is suitable for the magnon Bose-Einstein condensation (BEC).
description: 4 pages, 3 figures, revtex, submitted to PRL
Light Propagation on Quantum Curved Spacetime and Back reaction effects
Creators: name: Kozameh, Carlos
name: Parisi, Florencia
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study the electromagnetic field equations on an arbitrary quantum curved background in the semiclassical approximation of Loop Quantum Gravity. The effective interaction hamiltonian for the Maxwell and gravitational fields is obtained and the corresponding field equations, which can be expressed as a modified wave equation for the Maxwell potential, are derived. We use these results to analyze electromagnetic wave propagation on a quantum Robertson-Walker space time and show that Lorentz Invariance is not preserved. The formalism developed can be applied to the case where back reaction effects on the metric due to the electromagnetic field are taken into account, leading to non covariant field equations.
Join Inverse Rig Categories for Reversible Functional Programming, and Beyond
Creators: name: Kaarsgaard, Robin
name: Rennela, Mathys
Publisher: name: arXiv
Year: 2021
Subjects: subject: Logic in Computer Science (cs.LO)
subject: Programming Languages (cs.PL)
subject: Category Theory (math.CT)
subject: FOS: Computer and information sciences
subject: FOS: Mathematics

description: Reversible computing is a computational paradigm in which computations are deterministic in both the forward and backward direction, so that programs have well-defined forward and backward semantics. We investigate the formal semantics of the reversible functional programming language Rfun. For this purpose, we introduce join inverse rig categories, the natural marriage of join inverse categories and rig categories, which we show can be used to model the language Rfun, under reasonable assumptions. These categories turn out to be a particularly natural fit for reversible computing as a whole, as they encompass models for other reversible programming languages, notably Theseus and reversible flowcharts. This suggests that join inverse rig categories really are the categorical models of reversible computing.
description: In Proceedings MFPS 2021, arXiv:2112.13746
Fluctuations analysis of the spin susceptibility: Néel ordering revisited in dynamical mean field theory
Creators: name: Del Re, Lorenzo
name: Rohringer, Georg
Publisher: name: arXiv
Year: 2021
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: In this paper, we revisit the antiferromagnetic (AF) phase diagram of the single-band three-dimensional half-filled Hubbard model on a simple cubic lattice studied within the dynamical mean field theory (DMFT). Although this problem has been investigated extensively in the literature, a comprehensive understanding of the impact of the different one- and, in particular, two-particle local correlation functions of DMFT on the AF transition temperature is still missing. We have, hence, performed a fluctuation analysis of $T_N$ with respect to different local bosonic fluctuations (charge, spin, particle-particle) contained in the two-particle vertex of DMFT. Our results indicate that, beyond weak coupling, the screening of the DMFT vertex by local fluctuations leads to an enhancement of $T_N$ with respect to a random phase approximation (RPA) like calculation where this vertex is replaced by the bare interaction. The overall suppression of $T_N$ in DMFT with respect to RPA is then solely due to the incoherence introduced by the DMFT self-energy in the one-particle Green's functions. This illustrates the Janus-faced role of the local moment formation in the DMFT solution of the Hubbard model, which leads to completely opposite effects in the one- and two-particle correlation functions.
description: 15 pages, 13 figures
Exchangeable Random Networks
Creators: name: Bassetti, F.
name: Lagomarsino, M. Cosentino
name: Mandrá, S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Probability (math.PR)
subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 05C80 (Primary) 60G09 (Secondary)

description: We introduce and study a class of exchangeable random graph ensembles. They can be used as statistical null models for empirical networks, and as a tool for theoretical investigations. We provide general theorems that carachterize the degree distribution of the ensemble graphs, together with some features that are important for applications, such as subgraph distributions and kernel of the adjacency matrix. These results are used to compare to other models of simple and complex networks. A particular case of directed networks with power-law out--degree is studied in more detail, as an example of the flexibility of the model in applications.
description: to appear on "Internet Mathematics"
Multidirectionnal sweeping preconditioners with non-overlapping checkerboard domain decomposition for Helmholtz problems
Creators: name: Dai, Ruiyang
name: Modave, Axel
name: Remacle, Jean-François
name: Geuzaine, Christophe
Publisher: name: arXiv
Year: 2021
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: This paper explores a family of generalized sweeping preconditionners for Helmholtz problems with non-overlapping checkerboard partition of the computational domain. The domain decomposition procedure relies on high-order transmission conditions and cross-point treatments, which cannot scale without an efficient preconditioning technique when the number of subdomains increases. With the proposed approach, existing sweeping preconditioners, such as the symmetric Gauss-Seidel and parallel double sweep preconditioners, can be applied to checkerboard partitions with different sweeping directions (e.g. horizontal and diagonal). Several directions can be combined thanks to the flexible version of GMRES, allowing for the rapid transfer of information in the different zones of the computational domain, then accelerating the convergence of the final iterative solution procedure. Several two-dimensional finite element results are proposed to study and to compare the sweeping preconditioners, and to illustrate the performance on cases of increasing complexity.
Molecular cell biology of Rubella virus structural proteins
Creators: name: Hobman, Tom Cunningham
Publisher: name: University of British Columbia
Year: 2011

description: Rubella virus (RV) is a small, enveloped, positive-stranded RNA virus in the family Togaviridae, and bears striking similarities to the prototype alphaviruses Semliki Forest virus (SFV) and Sindbis virus (SV) in terms of genome organization and structural protein expression strategy. However unlike alphaviruses, RV infection of cultured cells is characterized by relatively long latency periods, slow replication kinetics, limited cytopathology, and the ability to establish a persistent infection in virtually every cell line capable of supporting its growth. RV virions contain three structural proteins C, E2, and El which are derived by post-translational processing of a precursor polyprotein pllO (NF₂-C-E2-El-COOH). Processing and intracellular transport of RV structural proteins has been studied by jn vitro and jn vivo expression of RV cDNAs. It was found that targeting of El and E2 into the endoplasmic reticulum was mediated by two independently functioning signal peptides. Coincident with translocation into the ER, both proteins underwent addition of N-linked glycans and proteolytic processing. C protein did not appear to play a role in the processing of pllO. Expression of the RV structural proteins in COS cells revealed that E2 exited the ER, and was transported through the Golgi to the cell surface in an El-independent manner, although coexpression of El seemed to increase the rate of transport. Conversely, El was retained in a Golgi-like region and was not found on the plasma membrane in the absence of E2. Oligonucleotide-directed mutagenesis of El and E2 cDNAs showed that El andE2 both contain three N-linked glycans respectively. Lack of glycosylation did not appear to affect the intracellular localization of the RV glycoproteins in COS cells. A number of significant differences between RV and SFV/SV structural protein expression strategies were discovered, and their possible relationship to RV virion assembly are discussed.
Prospects for precision measurements of atomic helium using direct frequency comb spectroscopy
Creators: name: Eyler, E. E.
name: Chieda, D. E.
name: Stowe, Matthew C.
name: Thorpe, Michael J.
name: Schibli, T. R.
name: Ye, Jun
Publisher: name: arXiv
Year: 2007
Subjects: subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We analyze several possibilities for precisely measuring electronic transitions in atomic helium by the direct use of phase-stabilized femtosecond frequency combs. Because the comb is self-calibrating and can be shifted into the ultraviolet spectral region via harmonic generation, it offers the prospect of greatly improved accuracy for UV and far-UV transitions. To take advantage of this accuracy an ultracold helium sample is needed. For measurements of the triplet spectrum a magneto-optical trap (MOT) can be used to cool and trap metastable 2^3S state atoms. We analyze schemes for measuring the two-photon $2^3S \to 4^3S$ interval, and for resonant two-photon excitation to high Rydberg states, $2^3S \to 3^3P \to n^3S,D$. We also analyze experiments on the singlet-state spectrum. To accomplish this we propose schemes for producing and trapping ultracold helium in the 1^1S or 2^1S state via intercombination transitions. A particularly intriguing scenario is the possibility of measuring the $1^1S \to 2^1S$ transition with extremely high accuracy by use of two-photon excitation in a magic wavelength trap that operates identically for both states. We predict a ``triple magic wavelength'' at 412 nm that could facilitate numerous experiments on trapped helium atoms, because here the polarizabilities of the 1^1S, 2^1S and 2^3S states are all similar, small, and positive.
description: Shortened slightly and reformatted for Eur. Phys. J. D
Clean Single-Valued Polylogarithms
Creators: name: Charlton, Steven
name: Duhr, Claude
name: Gangl, Herbert
Publisher: name: arXiv
Year: 2021
Subjects: subject: Number Theory (math.NT)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: We define a variant of real-analytic polylogarithms that are single-valued and that satisfy ''clean'' functional relations that do not involve any products of lower weight functions. We discuss the basic properties of these functions and, for depths one and two, we present some explicit formulas and results. We also give explicit formulas for the single-valued and clean single-valued version attached to the Nielsen polylogarithms $S_{n,2}(x)$, and we show how the clean single-valued functions give new evaluations of multiple polylogarithms at certain algebraic points.
description: Special Issue on Algebraic Structures in Perturbative Quantum Field Theory in honor of Dirk Kreimer for his 60th birthday
Singular point characterization in microscopic flows
Creators: name: Volpe, Giorgio
name: Volpe, Giovanni
name: Petrov, Dmitri
Publisher: name: arXiv
Year: 2007
Subjects: subject: Optics (physics.optics)
subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: We suggest an approach to microrheology based on optical traps in order to measure fluid fluxes around singular points of fluid flows. We experimentally demonstrate this technique, applying it to the characterization of controlled flows produced by a set of birefringent spheres spinning due to the transfer of light angular momentum. Unlike the previous techniques, this method is able to distinguish between a singular point in a complex flow and the absence of flow at all; furthermore it permits us to characterize the stability of the singular point.
description: 4 pages and 4 figures
Regimes of cosmic-ray diffusion in Galactic turbulence
Creators: name: Reichherzer, P.
name: Merten, L.
name: Dörner, J.
name: Tjus, J. Becker
name: Pueschel, M. J.
name: Zweibel, E. G.
Publisher: name: arXiv
Year: 2021
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: Cosmic-ray transport in astrophysical environments is often dominated by the diffusion of particles in a magnetic field composed of both a turbulent and a mean component. This process, which is two-fold turbulent mixing in that the particle motion is stochastic with respect to the field lines, needs to be understood in order to properly model cosmic-ray signatures. One of the most important aspects in the modeling of cosmic-ray diffusion is that fully resonant scattering, the most effective such process, is only possible if the wave spectrum covers the entire range of propagation angles. By taking the wave spectrum boundaries into account, we quantify cosmic-ray diffusion parallel and perpendicular to the guide field direction at turbulence levels above 5% of the total magnetic field. We apply our results of the parallel and perpendicular diffusion coefficient to the Milky Way. We show that simple purely diffusive transport is in conflict with observations of the inner Galaxy, but that just by taking a Galactic wind into account, data can be matched in the central 5 kpc zone. Further comparison shows that the outer Galaxy at $>5\,$kpc, on the other hand, should be dominated by perpendicular diffusion, likely changing to parallel diffusion at the outermost radii of the Milky Way.
description: Published in Springer Nature Applied Sciences
Detecting spatial patterns with the cumulant function. Part II: An application to El Nino
Creators: name: Bernacchia, Alberto
name: Naveau, Philippe
name: Vrac, Mathieu
name: Yiou, Pascal
Publisher: name: arXiv
Year: 2007
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences

description: The spatial coherence of a measured variable (e.g. temperature or pressure) is often studied to determine the regions where this variable varies the most or to find teleconnections, i.e. correlations between specific regions. While usual methods to find spatial patterns, such as Principal Components Analysis (PCA), are constrained by linear symmetries, the dependence of variables such as temperature or pressure at different locations is generally nonlinear. In particular, large deviations from the sample mean are expected to be strongly affected by such nonlinearities. Here we apply a newly developed nonlinear technique (Maxima of Cumulant Function, MCF) for the detection of typical spatial patterns that largely deviate from the mean. In order to test the technique and to introduce the methodology, we focus on the El Nino/Southern Oscillation and its spatial patterns. We find nonsymmetric temperature patterns corresponding to El Nino and La Nina, and we compare the results of MCF with other techniques, such as the symmetric solutions of PCA, and the nonsymmetric solutions of Nonlinear PCA (NLPCA). We found that MCF solutions are more reliable than the NLPCA fits, and can capture mixtures of principal components. Finally, we apply Extreme Value Theory on the temporal variations extracted from our methodology. We find that the tails of the distribution of extreme temperatures during La Nina episodes is bounded, while the tail during El Ninos is less likely to be bounded. This implies that the mean spatial patterns of the two phases are asymmetric, as well as the behaviour of their extremes.
description: 15 pages, 7 figures
Suppressed radio emission in supercluster galaxies: enhanced ram pressure in merging clusters?
Creators: name: Mauduit, Jean-Christophe
name: Mamon, Gary A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: The environmental influence on the 1.4 GHz continuum radio emission of galaxies is analyzed in a 600 deg2 region of the local Universe containing the Shapley Supercluster (SSC). Galaxies in the FLASH and 6dFGS redshift surveys are cross-identified with NVSS radio sources, selected in a subsample doubly complete in volume and luminosity. Environmental effects are studied through a smoothed density field (normalized with random catalogs with the same survey edges and redshift selection function) and the distance to the nearest cluster (R/r200, where r200 is the virial radius, whose relation to the aperture velocity dispersion is quantified). The fraction of high radio loudness (R_K=L_radio/L_K) galaxies in the 10 Mpc Abell 3558 cluster complex at the core of the SSC (SSC-CR) is half as large than elsewhere. In the SSC-CR, R_K is anti-correlated with the density of the large-scale environment and correlated with R/r200: central brightest cluster galaxies (BCGs) in the SSC-CR are 10x less radio-loud than BCGs elsewhere, with signs of suppressed radio loudness in the SSC-CR also present beyond the BCGs, out to at least 0.3 r200. This correlation is nearly as strong as the tight correlation of L_K with R/r200 (K-luminosity segregation), inside the SSC-CR. The suppression of radio loudness in SSC-CR BCGs can be attributed to cluster-cluster mergers that destroy the cool core and thus the supply of gas to the central AGN. We analytically demonstrate that the low radio loudness of non-BCG galaxies within SSC-CR clusters cannot be explained by direct major galaxy mergers or rapid galaxy flyby collisions, but by the loss of gas supply through the enhanced ram pressure felt when these galaxies cross the shock front between the 2 merging clusters and are later subjected to the stronger wind from the 2nd cluster.
description: Version consolidated with Erratum A&A 499, 45
Quantum simulators, continuous-time automata, and translationally invariant systems
Creators: name: Vollbrecht, K. G. H.
name: Cirac, J. I.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: The general problem of finding the ground state energy of lattice Hamiltonians is known to be very hard, even for a quantum computer. We show here that this is the case even for translationally invariant systems. We also show that a quantum computer can be built in a 1D chain with a fixed, translationally invariant Hamitonian consisting of nearest--neighbor interactions only. The result of the computation is obtained after a prescribed time with high probability.
description: partily rewritten and important references included
Parallel Tiled QR Factorization for Multicore Architectures
Creators: name: Buttari, Alfredo
name: Langou, Julien
name: Kurzak, Jakub
name: Dongarra, Jack
Publisher: name: arXiv
Year: 2007
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: As multicore systems continue to gain ground in the High Performance Computing world, linear algebra algorithms have to be reformulated or new algorithms have to be developed in order to take advantage of the architectural features on these new processors. Fine grain parallelism becomes a major requirement and introduces the necessity of loose synchronization in the parallel execution of an operation. This paper presents an algorithm for the QR factorization where the operations can be represented as a sequence of small tasks that operate on square blocks of data. These tasks can be dynamically scheduled for execution based on the dependencies among them and on the availability of computational resources. This may result in an out of order execution of the tasks which will completely hide the presence of intrinsically sequential tasks in the factorization. Performance comparisons are presented with the LAPACK algorithm for QR factorization where parallelism can only be exploited at the level of the BLAS operations.
description: 19 pages 14 figures
Phenomenology of spectral functions in disordered spin chains at infinite temperature
Creators: name: Vidmar, Lev
name: Krajewski, Bartosz
name: Bonca, Janez
name: Mierzejewski, Marcin
Publisher: name: arXiv
Year: 2021
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Studies of disordered spin chains have recently experienced a renewed interest, inspired by the question to which extent the exact numerical calculations comply with the existence of a many-body localization phase transition. For the paradigmatic random field Heisenberg spin chains, many intriguing features were observed when the disorder is considerable compared to the spin interaction strength. Here, we introduce a phenomenological theory that may explain some of those features. The theory is based on the proximity to the noninteracting limit, in which the system is an Anderson insulator. Taking the spin imbalance as an exemplary observable, we demonstrate that the proximity to the local integrals of motion of the Anderson insulator determines the dynamics of the observable at infinite temperature. In finite interacting systems our theory quantitatively describes its integrated spectral function for a wide range of disorders.
Superstring partition functions in the doubled formalism
Creators: name: Chowdhury, Sudipto Paul
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Computation of superstring partition function for the non-linear sigma model on the product of a two-torus and its dual within the scope of the doubled formalism is presented. We verify that it reproduces the partition functions of the toroidally compactified type--IIA and type--IIB theories for appropriate choices of the GSO projection.
description: 15 pages
Additional file 1 of Isolation and identification of active ingredients and biological activity of Dioscorea nipponica Makino
Creators: name: Xia, Guangqing
name: Zhao, Guanshu
name: Pei, Shichun
name: Zheng, Yanping
name: Zang, Hao
name: Li, Li
Publisher: name: figshare
Year: 2023
Subjects: Biochemistry
Pharmacology
Environmental Sciences not elsewhere classified
Chemical Sciences not elsewhere classified
Science Policy
Biological Sciences not elsewhere classified
Information Systems not elsewhere classified

description: Additional file 1: Figure S1. 1HNMR spectrum of compound 1. Figure S2. 13C NMR spectrum of compound 1. Figure S3. DEPT spectrum of compound 1. Figure S4. COSY spectrum of compound 1. Figure S5. HMBC spectrum of compound 1. Figure S6. HRESIMS spectrum of compound 1. Figure S7. 1H NMR spectrum of compound 2. Figure S8. 13C NMR spectrum of compound 2. Figure S9. HRESIMS spectrum of compound 2. Figure S10. 1HNMR spectrum of compound 3. Figure S11. 13C NMR spectrum of compound 3. Figure S12. EIMS spectrum of compound 3. Figure S13. 1H NMR spectrum of compound 4. Figure S14. 13C NMR spectrum of compound 4. Figure S15. EIMS spectrum of compound 4. Figure S16. 1H NMR spectrum of compound 5. Figure S17. 13C NMR spectrum of compound 5. Figure S18. 1H NMR spectrum of compound 6. Figure S19. 13C NMR spectrum of compound 6. Figure S20. EIMS spectrum of compound 6. Figure S21. 1H NMR spectrum of compound 7. Figure S22. 13C NMR spectrum of compound 7. Figure S23. EIMS spectrum of compound 7. Figure S24. 1H NMR spectrum of compound 8. Figure S25. 13C NMR spectrum of compound 8. Figure S26. EIMS spectrum of compound 8. Figure S27. 1H NMR spectrum of compound 9. Figure S28. 13C NMR spectrum of compound 9. Figure S29. EIMS spectrum of compound 9.
Réseaux & Pratiques collaboratives: vers une épistémographie de la construction des savoirs en ligne.
Creators: name: Bois, Christian
Publisher: name: Zenodo
Year: 2005
Subjects: épistémographie
systémographie
technographie
médiographie
sémiographie
grenier de savoirs en ligne
MOOC
Internet
Paradigme Web
épistémè
Michel Foucault
Bruno Latour
Peter Sloterdijk
wikipédia
communs
creative commons

description: En 2019, ce mémoire de thèse reste d’une grande actualité lorsque l’on cherche une méthode de recherche pour des objets complexes comme “la fabrique et l’usage de WikiPédia” “la conception des communs intellectuels et leur usage.”.
 Il est proposé d’identifier chaque dimension de l’objet de recherche et de réaliser une sous-thèse pour chaque dimension : épistémographie, systémographie, technographie, médiographie, sémiographie, etc. L’exemple pris est celui d’un grenier de savoir sur la construction des maisons en composite argileux - pisé, bauge, adobe, torchis.
 Aujourd’hui ce serait la fabrique des articles WikiPédia correspondant et leur utilisation par exemple dans un MOOC.