cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Trotter Derivation of Algorithms for Brownian and Dissipative Particle Dynamics
Creators: name: Thalmann, Fabrice
name: Farago, Jean
Publisher: name: arXiv
Year: 2007
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: This paper focuses on the temporal discretization of the Langevin dynamics, and on different resulting numerical integration schemes. Using a method based on the exponentiation of time dependent operators, we carefully derive a numerical scheme for the Langevin dynamics, that we found equivalent to the proposal of Ermak, and not simply to the stochastic version of the velocity-Verlet algorithm. However, we checked on numerical simulations that both algorithms give similar results, and share the same ``weak order two'' accuracy. We then apply the same strategy to derive and test two numerical schemes for the dissipative particle dynamics (DPD). The first one of them was found to compare well, in terms of speed and accuracy, with the best currently available algorithms.
description: to be published in J.Chem.Phys
2D and 3D Dense-Fluid Shear Flows via Nonequilibrium Molecular Dynamics. Comparison of Time-and-Space-Averaged Tensor Temperature and Normal Stresses from Doll's, Sllod, and Boundary-Driven Shear Algorithms
Creators: name: Hoover, Wm. G.
name: Hoover, Carol G.
name: Petravic, Janka
Publisher: name: arXiv
Year: 2008
Subjects: subject: Chaotic Dynamics (nlin.CD)
subject: FOS: Physical sciences

description: Homogeneous shear flows (with constant strainrate du/dy) are generated with the Doll's and Sllod algorithms and compared to corresponding inhomogeneous boundary-driven flows. We use one-, two-, and three-dimensional smooth-particle weight functions for computing instantaneous spatial averages. The nonlinear stress differences are small, but significant, in both two and three space dimensions. In homogeneous systems the sign and magnitude of the shearplane stress difference, P(xx) - P(yy), depend on both the thermostat type and the chosen shearflow algorithm. The Doll's and Sllod algorithms predict opposite signs for this stress difference, with the Sllod approach definitely wrong, but somewhat closer to the (boundary-driven) truth. Neither of the homogeneous shear algorithms predicts the correct ordering of the kinetic temperatures, T(xx) > T(zz) > T(yy).
description: 34 pages with 12 figures, under consideration by Physical Review E
Effect of Electron Interaction on Statistics of Conductance Oscillations in Open Quantum Dots: Does the Dephasing Time Saturate?
Creators: name: Ihnatsenka, S.
name: Zozoulenko, I. V.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We perform self-consistent quantum transport calculations in open quantum dots taking into account the effect of electron interaction. We demonstrative that in the regime of the ultralow temperatures $2πk_BT\lesssimΔ$ ($Δ$ being the mean level spacing), the electron interaction strongly affects the conductance oscillations and their statistics leading to a drastic deviation from the corresponding predictions for noninteracting electrons. In particular, it causes smearing of conductance oscillations, which is similar to the effect of temperature or inelastic scattering. For $2πk_BT\gtrsimΔ$ the influence of electron interaction on the conductance becomes strongly diminished. Our calculations (that are free from phenomenological parameters of the theory) are in good quantitative agreement with the observed ultralow temperature statistics (Huibers \textit{et al.}, Phys. Rev. Lett. \textbf{81}, 1917 (1998)). Our findings question a conventional interpretation of the ultralow temperature saturation of the coherence time in open dots which is based on the noninteracting theories where the electron interaction is neglected and the agrement with the experiment is achieved by introducing additional phenomenological channels of dephasing.
Induced gravity and entanglement entropy of 2D black holes
Creators: name: Cadoni, Mariano
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Using the fact that 2D Newton constant is wholly induced by a conformal field theory, we derive a formula for the entanglement entropy of the anti-de Sitter black hole in two spacetime dimensions. The leading term in the large black hole mass expansion of our formula reproduces exactly the Bekenstein-Hawking entropy S_{BH}, whereas the subleading term behaves as ln S_{BH}. This subleading term has the universal form typical for the entanglement entropy of physical systems described by effective conformal fields theories (e.g. one-dimensional statistical models at the critical point).
description: 6 pages
ASTE CO(3--2) Observations of the Southern Barred Spiral Galaxy NGC 986: a Large Gaseous Bar Filled with Dense Molecular Medium
Creators: name: Kohno, K.
name: Tosaki, T.
name: Miura, R.
name: Muraoka, K.
name: Sawada, T.
name: Nakanishi, K.
name: Kuno, N.
name: Sakai, T.
name: Sorai, K.
name: Kamegai, K.
name: Tanaka, K.
name: Okuda, T.
name: Endo, A.
name: Hatsukade, B.
name: Sameshima, M.
name: Ezawa, H.
name: Sakamoto, S.
name: Kamazaki, T.
name: Cortes, J.
name: Tamura, Y.
name: Fukuhara, M.
name: Iono, D.
name: Kawabe, R.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present CO(3-2) emission observations toward the 3'x3' (or 20x20kpc at a distance of 23Mpc) region of the southern barred spiral galaxy NGC 986 using the Atacama Submillimeter Telescope Experiment (ASTE). This effort is a part of our on-going extragalactic CO(3-2) imaging project ADIoS (ASTE Dense gas Imaging of Spiral galaxies). Our CO(3-2) image revealed the presence of a large (the major axis is 14 kpc in total length) gaseous bar filled with dense molecular medium along the dark lanes observed in optical images. This is the largest ``dense-gas rich bar'' known to date. The dense gas bar discovered in NGC 986 could be a huge reservoir of possible ``fuel'' for future starbursts in the central region, and we suggest that the star formation in the central region of NGC 986 could still be in a growing phase. We found a good spatial coincidence between the overall distributions of dense molecular gas traced by CO(3-2) and the massive star formation depicted by H$α$. The global CO(3-2) luminosity $L'_{\rm CO(3-2)}$ of NGC 986 was determined to be $(5.4 \pm 1.1) \times 10^8$ K km s$^{-1}$ pc$^2$. The CO(3-2)/CO(1-0) integrated intensity ratio was found to be 0.60 +/- 0.13 at a spatial resolution of 44'' or 5 kpc, and a CO(3-2)/CO(2-1) ratio was 0.67 +/- 0.14 at a beam size of ~25'' or ~2.8 kpc. These line ratios suggest moderate excitation conditions of CO lines ($n_{\rm H_2} \sim 10^{3-4}$ cm$^{-3}$) in the central a few kpc region of NGC 986.
description: PASJ, in press. See http://www.nro.nao.ac.jp/~f0212kk/00ASTE986CO32/n986-kk45.pdf for a version with full resolution figures
A simple test for hidden variables in spin-1 system
Creators: name: Klyachko, Alexander A.
name: Can, M. Ali
name: Binicioğlu, Sinem
name: Shumovsky, Alexander S.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We resolve an old problem about the existence of hidden parameters in a three-dimensional quantum system by constructing an appropriate Bell's type inequality. This reveals a nonclassical nature of most spin-$1$ states. We shortly discuss some physical implications and an underlying cause of this nonclassical behavior, as well as a perspective of its experimental verification.
description: 4 pages, 1 figure
Magnetic Ordering of Nuclear Spins in an Interacting 2D Electron Gas
Creators: name: Simon, Pascal
name: Braunecker, Bernd
name: Loss, Daniel
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 investigate the magnetic behavior of nuclear spins embedded in a 2D interacting electron gas using a Kondo lattice model description. We derive an effective magnetic Hamiltonian for the nuclear spins which is of the RKKY type and where the interactions between the nuclear spins are strongly modified by the electron-electron interactions. We show that the nuclear magnetic ordering at finite temperature relies on the (anomalous) behavior of the 2D static electron spin susceptibility, and thus provides a connection between low-dimensional magnetism and non-analyticities in interacting 2D electron systems. Using various perturbative and non-perturbative approximation schemes in order to establish the general shape of the electron spin susceptibility as function of its wave vector, we show that the nuclear spins locally order ferromagnetically, and that this ordering can become global in certain regimes of interest. We demonstrate that the associated Curie temperature for the nuclear system increases with the electron-electron interactions up to the millikelvin range.
description: 18 pages, 2 figures, final version
A Catalogue of M51 type Galaxy Associations
Creators: name: Jokimaki, Ari
name: Orr, Harley "Skip"
name: Russell, David G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A catalog of 232 apparently interacting galaxy pairs of the M51 class is presented. Catalog members were identified from visual inspection of mult-band images in the IRSA archive. The major findings in the compilation of this catalog are (1) A surprisingly low number of the main galaxies in M51 systems are early type spirals and barred spirals. (2) Over 70% of the main galaxies in M51 systems are 2-armed spirals. (3) Some systems that were classified as M51 types in previous studies are not M51 types as defined in this catalog. There were a number of systems previously classified as M51 systems for which the companion is identified as an HII region within the main galaxy or a foreground star within the Milky Way. (4) It was found that only 18% of the M51 type companions have redshift measurements in the literature. There is a significant need for spectroscopic study of the companions in order to improve the value of the catalog as a sample for studying the effects of M51 type interaction on galaxy dynamics, morphology, and star formation. Further spectroscopy will also help constrain the statistics of possible chance projections between foreground and background galaxies in this catalog. The catalog also contains over 430 additional systems which are classified as "possible M51" systems. The reasons for classifying certain systems as possible M51 systems are discussed.
description: 19 pages including 6 figures and tables 3-8, Tables 1 and 2 are found at http://www.jorcat.com, Accepted for publication in Astrophysics and Space Science
States of the Dirac equation in confining potentials
Creators: name: Giachetti, R.
name: Sorace, E.
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We study the Dirac equation in confining potentials with pure vector coupling, proving the existence of metastable states with longer and longer lifetimes as the non-relativistic limit is approached and eventually merging with continuity into the Schrödinger bound states. We believe that the existence of these states could be relevant in high energy model construction and in understanding possible resonant scattering effects in systems like Graphene. We present numerical results for the linear and the harmonic cases and we show that the the density of the states of the continuous spectrum is well described by a sum of Breit-Wigner lines. The width of the line with lowest positive energy, as expected, reproduces very well the Schwinger pair production rate for a linear potential: we thus suggest a different way of obtaining informations on the pair production in unbounded, non uniform electric fields, where very little is known.
description: 4 pages
Range Corrections to Three-Body Observables near a Feshbach Resonance
Creators: name: Platter, Lucas
name: Ji, Chen
name: Phillips, Daniel R.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Other Condensed Matter (cond-mat.other)
subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: A non-relativistic system of three identical particles will display a rich set of universal features known as Efimov physics if the scattering length a is much larger than the range l of the underlying two-body interaction. An appropriate effective theory facilitates the derivation of both results in the |a| goes to infinity limit and finite-l/a corrections to observables of interest. Here we use such an effective-theory treatment to consider the impact of corrections linear in the two-body effective range, r_s on the three-boson bound-state spectrum and recombination rate for |a| much greater than |r_s|. We do this by first deriving results appropriate to the strict limit |a| goes to infinity in coordinate space. We then extend these results to finite a using once-subtracted momentum-space integral equations. We also discuss the implications of our results for experiments that probe three-body recombination in Bose-Einstein condensates near a Feshbach resonance.
description: 28 pages, 3 figures
Of mice and men: Sparse statistical modeling in cardiovascular genomics
Creators: name: Seo, David M.
name: Goldschmidt-Clermont, Pascal J.
name: West, Mike
Publisher: name: arXiv
Year: 2007
Subjects: subject: Applications (stat.AP)
subject: FOS: Computer and information sciences

description: In high-throughput genomics, large-scale designed experiments are becoming common, and analysis approaches based on highly multivariate regression and anova concepts are key tools. Shrinkage models of one form or another can provide comprehensive approaches to the problems of simultaneous inference that involve implicit multiple comparisons over the many, many parameters representing effects of design factors and covariates. We use such approaches here in a study of cardiovascular genomics. The primary experimental context concerns a carefully designed, and rich, gene expression study focused on gene-environment interactions, with the goals of identifying genes implicated in connection with disease states and known risk factors, and in generating expression signatures as proxies for such risk factors. A coupled exploratory analysis investigates cross-species extrapolation of gene expression signatures--how these mouse-model signatures translate to humans. The latter involves exploration of sparse latent factor analysis of human observational data and of how it relates to projected risk signatures derived in the animal models. The study also highlights a range of applied statistical and genomic data analysis issues, including model specification, computational questions and model-based correction of experimental artifacts in DNA microarray data.
description: Published at http://dx.doi.org/10.1214/07-AOAS110 in the Annals of Applied Statistics (http://www.imstat.org/aoas/) by the Institute of Mathematical Statistics (http://www.imstat.org)
The Proton Elastic Form Factor Ratio at Low Momentum Transfer
Creators: name: Ron, G.
name: Glister, J.
name: Lee, B.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: High precision measurements of the proton elastic form factor ratio have been made at four-momentum transfers, Q^2, between 0.2 and 0.5 GeV^2. The new data, while consistent with previous results, clearly show a ratio less than unity and significant differences from the central values of several recent phenomenological fits. By combining the new form-factor ratio data with an existing cross-section measurement, one finds that in this Q^2 range the deviation from unity is primarily due to GEp being smaller than the dipole parameterization.
description: 5 pages, 2 figures
A determination of parton distributions with faithful uncertainty estimation
Creators: name: Ball, Richard D.
name: Del Debbio, Luigi
name: Forte, Stefano
name: Guffanti, Alberto
name: Latorre, Jose I.
name: Piccione, Andrea
name: Rojo, Juan
name: Ubiali, Maria
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We present the determination of a set of parton distributions of the nucleon, at next-to-leading order, from a global set of deep-inelastic scattering data: NNPDF1.0. The determination is based on a Monte Carlo approach, with neural networks used as unbiased interpolants. This method, previously discussed by us and applied to a determination of the nonsinglet quark distribution, is designed to provide a faithful and statistically sound representation of the uncertainty on parton distributions. We discuss our dataset, its statistical features, and its Monte Carlo representation. We summarize the technique used to solve the evolution equations and its benchmarking, and the method used to compute physical observables. We discuss the parametrization and fitting of neural networks, and the algorithm used to determine the optimal fit. We finally present our set of parton distributions. We discuss its statistical properties, test for its stability upon various modifications of the fitting procedure, and compare it to other recent parton sets. We use it to compute the benchmark W and Z cross sections at the LHC. We discuss issues of delivery and interfacing to commonly used packages such as LHAPDF.
description: 73 pages, 16 figures: final version, to be published in Nucl. Phys. B. Two figures added (fig6 and fig.10); discussion on inconsistent data added (sect 5.5); one reference added; numerous typos corrected and a few clarifications added. Missing factor of r_f supplied in eqs. 132,133,137,138,142,143,149,150,153 and 154
Energy-minimizing two black holes initial data
Creators: name: Jezierski, Jacek
name: Kijowski, Jerzy
name: Leski, Szymon
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: An attempt to construct the ``ground state'' vacuum initial data for the gravitational field surrounding two black holes is presented. The ground state is defined as the gravitational initial data minimizing the ADM mass within the class of data for which the masses of the holes and their distance are fixed. To parameterize different geometric arrangements of the two holes (and, therefore, their distance) we use an appropriately chosen scale factor. A method for analyzing the variations of the ADM mass and the masses (areas) of the horizons in terms of gravitational degrees of freedom is proposed. The Misner initial data are analyzed in this context: it is shown that they do not minimize the ADM mass.
description: Minor corrections, 2 references added
Covariant anomaly and Hawking radiation from the modified black hole in the rainbow gravity theory
Creators: name: Peng, Jun-Jin
name: Wu, Shuang-Qing
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: Recently, Banerjee and Kulkarni (R. Banerjee, S. Kulkarni, arXiv:0707.2449 [hep-th]) suggested that it is conceptually clean and economical to use only the covariant anomaly to derive Hawking radiation from a black hole. Based upon this simplified formalism, we apply the covariant anomaly cancellation method to investigate Hawking radiation from a modified Schwarzschild black hole in the theory of rainbow gravity. Hawking temperature of the gravity's rainbow black hole is derived from the energy-momentum flux by requiring it to cancel the covariant gravitational anomaly at the horizon. We stress that this temperature is exactly the same as that calculated by the method of cancelling the consistent anomaly.
description: 5 pages
Weights of mixed tilting sheaves and geometric Ringel duality
Creators: name: Yun, Zhiwei
Publisher: name: arXiv
Year: 2008
Subjects: subject: Algebraic Geometry (math.AG)
subject: Representation Theory (math.RT)
subject: FOS: Mathematics
subject: 14F20, 14L30, 20G25

description: We describe several general methods for calculating weights of mixed tilting sheaves. We introduce a notion called "non-cancellation property" which implies a strong uniqueness of mixed tilting sheaves and enables one to calculate their weights effectively. When we have a certain Radon transform, we prove a geometric analogue of Ringel duality which sends tilting objects to projective objects. We apply these methods to (partial) flag varieties and affine (partial) flag varieties and show that the weight polynomials of mixed tilting sheaves on flag and affine flag varieties are essentially given by Kazhdan-Lusztig polynomials. This verifies a mixed geometric analogue of a conjecture by W.Soergel in \cite{Sg1}.
description: Updated version; To appear in Selecta. Math.; 19 pages
Recent progress constraining the nuclear equation of state from astrophysics and heavy ion reactions
Creators: name: Fuchs, Christian
Publisher: name: arXiv
Year: 2007
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The quest for the nuclear equation of state (EoS) at high densities and/or extreme isospin is one of the longstanding problems of nuclear physics. Ab initio calculations for the nuclear many-body problem make predictions for the density and isospin dependence of the EoS far away from the saturation point of nuclear matter. On the other hand, in recent years substantial progress has been mode to constrain the EoS both, from the astrophysical side and from accelerator based experiments. Heavy ion experiments support a soft EoS at moderate densities while recent neutron star observations require a ``stiff'' high density behavior. Both constraints are discussed and shown to be in agreement with the predictions from many-body theory.
description: Invited talk given at NPA III, Dresden, Germany, March 2007
Collinear factorization for deep inelastic scattering structure functions at large Bjorken xB
Creators: name: Accardi, Alberto
name: Qiu, Jian-Wei
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We examine the uncertainty of perturbative QCD factorization for hadron structure functions in deep inelastic scattering at a large value of the Bjorken variable xB. We analyze the target mass correction to the structure functions by using the collinear factorization approach in the momentum space. We express the long distance physics of structure functions and the leading target mass corrections in terms of parton distribution functions with the standard operator definition. We compare our result with existing work on the target mass correction. We also discuss the impact of a final-state jet function on the extraction of parton distributions at large fractional momentum x.
description: 18 pages, 10 figures; discussion on baryon number conservation clarified
Luminosity determination at HERA-B
Creators: name: B Collaboration
Publisher: name: arXiv
Year: 2007
Subjects: subject: Data Analysis, Statistics and Probability (physics.data-an)
subject: FOS: Physical sciences

description: A detailed description of an original method used to measure the luminosity accumulated by the HERA-B experiment for a data sample taken during the 2002-2003 HERA running period is reported. We show that, with this method, a total luminosity measurement can be achieved with a typical precision, including overall systematic uncertainties, at a level of 5% or better. We also report evidence for the detection of delta-rays generated in the target and comment on the possible use of such delta rays to measure luminosity.
description: 24 pages, 5 figures
Gravitational waves from 3D MHD core collapse simulations
Creators: name: Scheidegger, S.
name: Fischer, T.
name: Whitehouse, S. C.
name: Liebendoerfer, M.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the gravitational wave analysis from rotating (model s15g) and nearly non-rotating (model s15h) 3D MHD core collapse supernova simulations at bounce and the first couple of ten milliseconds afterwards. The simulations are launched from 15M_{\odot} progenitor models stemming from stellar evolution calculations. Gravity is implemented by a spherically symmetric effective general relativistic potential. The input physics uses the Lattimer-Swesty equation of state for hot, dense matter and a neutrino parametrisation scheme that is accurate until the first few ms after bounce. The 3D simulations allow us to study features already known from 2D simulations as well as nonaxisymmetric effects. In agreement with recent results we find only type I gravitational wave signals at core bounce. In the later stage of the simulations, one of our models (s15g) shows nonaxisymmetric gravitational wave emission caused by a low T/|W| dynamical instability, while the other model radiates gravitational waves due to a convective instability in the protoneutron star. The total energy released in gravitational waves within the considered time intervals is 1.52\times10^{-7}M_{\odot} (s15g) and 4.72\times10^{-10}M_{\odot} (s15h). Both core collapse simulations indicate that corresponding events in our Galaxy would be detectable either by the LIGO or Advanced LIGO detector.
description: 11 pages, 8 figures, to be published in A&A
Valley splitting in Si quantum dots embedded in SiGe
Creators: name: Srinivasan, S.
name: Klimeck, G.
name: Rokhinson, L. P.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We examine energy spectra of Si quantum dots embedded into Si_{0.75}Ge_{0.25} buffers using atomistic numerical calculations for dimensions relevant to qubit implementations. The valley degeneracy of the lowest orbital state is lifted and valley splitting fluctuates with monolayer frequency as a function of the dot thickness. For dot thicknesses <6 nm valley splitting is found to be >150 ueV. Using the unique advantage of atomistic calculations we analyze the effect of buffer disorder on valley splitting. Disorder in the buffer leads to the suppression of valley splitting by a factor of 2.5, the splitting fluctuates with ~20 ueV for different disorder realizations. Through these simulations we can guide future experiments into regions of low device-to-device fluctuations.
description: 4 pages, 4 figures
Valuing Our Scans: Assessing the Value and Impact  of Digitizing Ethnographic Collections for Access
Creators: name: Punzalan, Ricardo
name: Butler, Brian
Publisher: name: Digital Repository at the University of Maryland
Year: 2014
Subjects: Digitization Impact Assessment
Digitized Ethnographic Collections

description: Museums and the Web 2014 Conference Proccedings
description: Over the years, the heritage field has made great strides at making ethnographic and anthropological collections available in their digitized formats. Through digitization, institutions are finding creative ways to make these materials more discoverable and accessible. Access to ethnographic collections is increasingly mediated through digital avenues. Yet, despite these advances in digitization, no clear criteria have been proposed for assessing the impact and use of online digitized collections. Moreover, there is scant understanding of the initial selection criteria used by heritage professionals and administrators for digitizing particular collections. What are the goals of digitizing ethnographic collections? How are these goals set? And how are these goals assessed?

This paper highlights the approaches and perspectives employed in a collaborative project between the Smithsonian Institution and the University of Maryland College of Information Studies. Our project aims to identify important considerations in assessing the value and impact of digitization of ethnographic collections. This paper presents preparatory work for this project and is organized in three parts. The first describes the profound changes happening within the LAM sector. In particular, we look at the effects brought about by the expanding role of digitization and online access as fundamental institutional functions of heritage repositories. The second provides an overview of the current literature on impact and assessment that address the issue of valuing digitized collections. Third, we outline our ongoing collaborative research project that examines cases of ethnographic digitization projects in seven cultural heritage institutions. Finally, conclude by offering “five considerations” that we propose to frame efforts for assessing the impact of value of digitized ethnographic collections.
description: University of Maryland/Smithsonian Institution Seed Grant
Magnification relations for Kerr lensing and testing Cosmic Censorship
Creators: name: Werner, M. C.
name: Petters, A. O.
Publisher: name: arXiv
Year: 2007
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A Kerr black hole with mass parameter m and angular momentum parameter a acting as a gravitational lens gives rise to two images in the weak field limit. We study the corresponding magnification relations, namely the signed and absolute magnification sums and the centroid up to post-Newtonian order. We show that there are post-Newtonian corrections to the total absolute magnification and centroid proportional to a/m, which is in contrast to the spherically symmetric case where such corrections vanish. Hence we also propose a new set of lensing observables for the two images involving these corrections, which should allow measuring a/m with gravitational lensing. In fact, the resolution capabilities needed to observe this for the Galactic black hole should in principle be accessible to current and near-future instrumentation. Since a/m >1 indicates a naked singularity, a most interesting application would be a test of the Cosmic Censorship conjecture. The technique used to derive the image properties is based on the degeneracy of the Kerr lens and a suitably displaced Schwarzschild lens at post-Newtonian order. A simple physical explanation for this degeneracy is also given.
description: 13 pages, version 2: references added, minor changes. To appear in Phys. Rev. D
Quantitative optical and near-infrared spectroscopy of molecular hydrogen towards HH91A
Creators: name: Gredel, Roland
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Integral-field spectroscopy of molecular hydrogen in the optical wavelength region and complementary long-slit near-infrared spectroscopy are presented towards HH91A.The detection of some 200 H_2 lines arising from ro-vibrational levels up to v'=8 ranging between 7700A and 2.3 microns is reported. The emission arises from thermally excited gas where the bulk of the material is at 2750 K and where 1% is at 6000 K. The total column density of shocked gas is N(H_2) = 10^{18} cm^{-2}. Non-thermal excitation scenarios such as UV-fluorescence do not contribute to the excitation of H_2 towards HH91A. The emission is explained in terms of a slow non-dissociative J-shock which propagates into a low-density medium which has been swept-up by previous episodes of outflows which have occurred in the evolved HH90/91 complex.
description: A&A accepted
Demonstrating the model nature of the high-temperature superconductor HgBa$_2$CuO$_{4+Δ}$
Creators: name: Barisic, Neven
name: Li, Yuan
name: Zhao, Xudong
name: Cho, Yong-Chan
name: Chabot-Couture, Guillaume
name: Yu, Guichuan
name: Greven, Martin
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: The compound HgBa$_2$CuO$_{4+Δ}$ (Hg1201) exhibits a simple tetragonal crystal structure and the highest superconducting transition temperature (T$_c$) among all single Cu-O layer cuprates, with T$_c$ = 97 K (onset) at optimal doping. Due to a lack of sizable single crystals, experimental work on this very attractive system has been significantly limited. Thanks to a recent breakthrough in crystal growth, such crystals have now become available. Here, we demonstrate that it is possible to identify suitable heat treatment conditions to systematically and uniformly tune the hole concentration of Hg1201 crystals over a wide range, from very underdoped (T$_c$ = 47 K, hole concentration p ~ 0.08) to overdoped (T$_c$ = 64 K, p ~ 0.22). We then present quantitative magnetic susceptibility and DC charge transport results that reveal the very high-quality nature of the studied crystals. Using XPS on cleaved samples, we furthermore demonstrate that it is possible to obtain large surfaces of good quality. These characterization measurements demonstrate that Hg1201 should be viewed as a model high-temperature superconductor, and they provide the foundation for extensive future experimental work.
description: 15 pages, 6 Figures
Hodographic Vortices
Creators: name: Moro, Antonio
Publisher: name: arXiv
Year: 2008
Subjects: subject: Optics (physics.optics)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: Vortices are screw phase dislocations associated with helicoidal wave-fronts. In nonlinear optics, vortices arise as singular solutions to the phase-intensity equations of geometric optics. They exist for a general class of nonlinear response functions. In this sense, vortices possess a universal character. Analysis of geometric optics equations on the hodograph plane leads to deformed vortex type solutions that are sensitive to the form of the nonlinearity. The case of a Kerr type nonlinear response is discussed as a specific example.
description: Revised version, 8 pages
Neutrinos from active black holes, sources of ultra high energy cosmic rays
Creators: name: Becker, Julia K.
name: Biermann, Peter L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: A correlation between the highest energy Cosmic Rays (above ~ EeV) and the distribution of active galactic nuclei (AGN) gives rise to a prediction of neutrino production in the same sources. In this paper, we present a detailed AGN model, predicting neutrino production near the foot of the jet, where the photon fields from the disk and synchrotron radiation from the jet itself create high optical depths for proton-photon interactions. The protons escape from later shocks where the emission region is optically thin for proton-photon interactions. Consequently, Cosmic Rays are predicted to come from FR-I galaxies, independent of the orientation of the source. Neutrinos, on the other hand, are only observable from sources directing their jet towards Earth, i.e. flat spectrum radio sources and in particular BL Lac type objects, due to the strongly boosted neutrino emission.
description: Accepted for publication in Astroparticle Physics; 30 pages, 8 figures
Displacement convexity and minimal fronts at phase boundaries
Creators: name: Carlen, Eric A.
name: Carvalho, Maria C.
name: Esposito, Raffaele
name: Lebowitz, Joel L.
name: Marra, Rossana
Publisher: name: arXiv
Year: 2007
Subjects: subject: Functional Analysis (math.FA)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 49S05; 52A40; 82B26

description: We show that certain free energy functionals that are not convex with respect to the usual convex structure on their domain of definition, are strictly convex in the sense of displacement convexity under a natural change of variables. We use this to show that in certain cases, the only critical points of these functionals are minimizers. This approach based on displacement convexity permits us to treat multicomponent systems as well as single component systems. The developments produce new examples of displacement convex functionals, and, in the multi-component setting, jointly displacement convex functionals.
description: This version contains additional references as well as a new section in which the joint convexity is applied to the uniqueness problem in higher dimensions
When hot meets cold: post-flare coronal rain
Creators: name: Ruan, Wenzhi
name: Zhou, Yuhao
name: Keppens, Rony
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Most solar flares demonstrate a prolonged, hourlong post-flare (or gradual) phase, characterized by arcade-like, post-flare loops (PFLs) visible in many extreme ultraviolet (EUV) passbands. These coronal loops are filled with hot -- $\sim 30 \,\mathrm{MK}$ -- and dense plasma, evaporated from the chromosphere during the impulsive phase of the flare, and they very gradually recover to normal coronal density and temperature conditions. During this gradual cooling down to $\sim 1 \,\mathrm{MK}$ regimes, much cooler -- $\sim 0.01 \,\mathrm{MK}$ -- and denser coronal rain is frequently observed inside PFLs. Understanding PFL dynamics in this long-duration, gradual phase is crucial to the entire corona-chromosphere mass and energy cycle. Here we report a simulation in which a solar flare evolves from pre-flare, over impulsive phase all the way into its gradual phase, which successfully reproduces post-flare coronal rain. This rain results from catastrophic cooling caused by thermal instability, and we analyse the entire mass and energy budget evolution driving this sudden condensation phenomenon. We find that the runaway cooling and rain formation also induces the appearance of dark post-flare loop systems, as observed in EUV channels. We confirm and augment earlier observational findings, suggesting that thermal conduction and radiative losses alternately dominate the cooling of PFLs.
description: accepted by ApJL
Untangling a Planar Graph
Creators: name: Goaoc, Xavier
name: Kratochvil, Jan
name: Okamoto, Yoshio
name: Shin, Chan-Su
name: Spillner, Andreas
name: Wolff, Alexander
Publisher: name: arXiv
Year: 2007
Subjects: subject: Computational Geometry (cs.CG)
subject: Discrete Mathematics (cs.DM)
subject: FOS: Computer and information sciences
subject: G.2.2; I.3.5

description: A straight-line drawing $δ$ of a planar graph $G$ need not be plane, but can be made so by \emph{untangling} it, that is, by moving some of the vertices of $G$. Let shift$(G,δ)$ denote the minimum number of vertices that need to be moved to untangle $δ$. We show that shift$(G,δ)$ is NP-hard to compute and to approximate. Our hardness results extend to a version of \textsc{1BendPointSetEmbeddability}, a well-known graph-drawing problem. Further we define fix$(G,δ)=n-shift(G,δ)$ to be the maximum number of vertices of a planar $n$-vertex graph $G$ that can be fixed when untangling $δ$. We give an algorithm that fixes at least $\sqrt{((\log n)-1)/\log \log n}$ vertices when untangling a drawing of an $n$-vertex graph $G$. If $G$ is outerplanar, the same algorithm fixes at least $\sqrt{n/2}$ vertices. On the other hand we construct, for arbitrarily large $n$, an $n$-vertex planar graph $G$ and a drawing $δ_G$ of $G$ with fix$(G,δ_G) \le \sqrt{n-2}+1$ and an $n$-vertex outerplanar graph $H$ and a drawing $δ_H$ of $H$ with fix$(H,δ_H) \le 2 \sqrt{n-1}+1$. Thus our algorithm is asymptotically worst-case optimal for outerplanar graphs.
description: (v5) Minor, mostly linguistic changes
Unveiling the broad band X-ray continuum and iron line complex in Mkr 841
Creators: name: Petrucci, P. O.
name: Ponti, G.
name: Matt, G.
name: Longinotti, A. L.
name: Malzac, J.
name: Mouchet, M.
name: Boisson, C.
name: Maraschi, L.
name: Nandra, K.
name: Ferrando, P.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Mkr 841 is a bright Seyfert 1 galaxy known to harbor a strong soft excess and a variable K$α$ iron line. It has been observed during 3 different periods by XMM for a total cumulated exposure time of $\sim$108 ks. We present in this paper a broad band spectral analysis of the complete EPIC-pn data sets. We were able to test two different models for the soft excess, a relativistically blurred photoionized reflection (\r model) and a relativistically smeared ionized absorption (\a model). The continuum is modeled by a simple cut-off power law and we also add a neutral reflection. These observations reveal the extreme and puzzling spectral and temporal behaviors of the soft excess and iron line. The 0.5-3 keV soft X-ray flux decreases by a factor 3 between 2001 and 2005 and the line shape appears to be a mixture of broad and narrow components. We succeed in describing this complex broad-band 0.5-10 keV spectral variability using either \r or \a to fit the soft excess. Both models give statistically equivalent results even including simultaneous BeppoSAX data up to 200 keV. Both models are consistent with the presence of remote reflection characterized by a constant narrow component in the data. However they differ in the presence of a broad line component present in \r but not needed in \a. This study also reveals the sporadic presence of relativistically redshifted narrow iron lines.
description: Accepted in A&A. 17 pages and 21 figures
Testing TwitterWeave: An Application of the New IDS Web Tool for Tracking Research
Creators: name: Scott, Alistair
Publisher: name: figshare
Year: 2021
Subjects: subject: 100599 Communications Technologies not elsewhere classified
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: To enable people to do this, a software application, ‘TwitterWeave’, was recently developedas part of the Institute of Development Studies (IDS) programme on StrengtheningEvidence-based Policy. This free-to-use web application allows users to track not only whatis being said on Twitter about a particular topic, but also who is saying it. Many Twittertrackingtools exist, but the innovative feature of TwitterWeave is the way it organises anddisplays Twitter information into visualisations of chronological threads of related tweets,retweets and replies.
Transparency of 0.2% GdCl3 Doped Water in a Stainless Steel Test Environment
Creators: name: Coleman, W.
name: Bernstein, A.
name: Dazeley, S.
name: Svoboda, R.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Instrumentation and Detectors (physics.ins-det)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The possibility of neutron and neutrino detection using water Cerenkov detectors doped with gadolinium holds the promise of constructing very large high-efficiency detectors with wide-ranging application in basic science and national security. This study addressed a major concern regarding the feasibility of such detectors: the transparency of the doped water to the ultraviolet Cerenkov light. We report on experiments conducted using a 19-meter water transparency measuring instrument and associated materials test tank. Sensitive measurements of the transparency of water doped with 0.2% GdCl3 at 337nm, 400nm and 420nm were made using this instrument. These measurements indicate that GdCl3 is not an appropriate dopant in stainless steel constructed water Cerenkov detectors.
description: 17 pages, 11 figures, corrects typos, changes formatting, adds error bars to figure 7
10,000 Plant Genome Project (Phase I)
Creators: name: 燕南 范
Publisher: name: CNGB
Year: 2021
Subjects: Genome sequencing and assembly
Raw sequence reads
Genome sequencing
Assembly
Multispecies
Agricultural

description: The 10,000 plants (tenKP or 10KP) aims to sequence over 10,000 genomes representing every major clade of plants and eukaryotic microbes. This project would generate large-scale plant genome data within the next five years (2017-2022), addressing fundamental questions about plant evolution. Major supporters include Beijing Genomics Institute in Shenzhen (BGI-Shenzhen) and China National Gene Bank (CNGB). BGI corporate will support this project by developing new tools for de novo genome sequencing and assembly on MGISEQ platforms.
Quark motional effects on the interquark potential in baryons
Creators: name: Yamamoto, Arata
name: Suganuma, Hideo
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study the heavy-heavy-light quark ($QQq$) system in a non-relativistic potential model, and investigate the quark motional effect on the inter-two-quark potential in baryons. We adopt the Hamiltonian with the static three-quark potential which is obtained by the first-principle calculation of lattice QCD, rather than the two-body force in ordinary quark models. Using the renormalization-group inspired variational method in discretized space, we calculate the ground-state energy of $QQq$ systems and the light-quark spatial distribution. We find that the effective string tension between the two heavy quarks is reduced compared to the static three-quark case. This reduction of the effective string tension originates from the geometrical difference between the inter-quark distance and the flux-tube length, and is conjectured to be a general property for baryons.
description: 7 pages, 6 figures
Vlasov limit and discreteness effects in cosmological N-body simulations
Creators: name: Marcos, B.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We present the problematic of controlling the discreteness effects in cosmological N-body simulations. We describe a perturbative treatment which gives an approximation describing the evolution under self-gravity of a lattice perturbed from its equilibrium, which allows to trace the evolution of the fully discrete distribution until the time when particles approach one another ("shell-crossing"). Perturbed lattices are typical initial conditions for cosmological N-body simulations and thus we can describe precisely the early time evolution of these simulations. A quantitative comparison with fluid Lagrangian theory permits to study discreteness effects in the linear regime of the simulations. We show finally some work in progress about quantifying discreteness effects in the non-perturbative (highly non-linear) regime of cosmological N-body simulations by evolving different discretizations of the same continuous density field.
description: 8 pages, proceedings (refereed) of "Vlasovia 2006", 2nd int'l workshop on the theory and applications of the Vlasov equation, Florence, September 2006. A more detailed report on recent progress may be found at arXiv:0805.1357
α_S from LEP
Creators: name: Kluth, Stefan
Publisher: name: arXiv
Year: 2007
Subjects: subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: Recent results on measurements of the strong coupling $α_S$ from LEP are reported. These include analyses of the 4-jet rate using the Durham or Cambridge algorithm, of hadronic $Z^0$ decays with hard final state photon radiation, of scaling violations of the fragmentation function, of the longitudinal cross section, of the $Z^0$ lineshape and of hadronic $τ$ lepton decays.
description: 3 pages, 2 figures, invited parallel talk at EPS HEP 2007 Manchester, added comment on estimation of theory error in section 5 and new ref [10]