cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Hard-constraining Neumann boundary conditions in physics-informed neural networks via Fourier feature embeddings
Creators: name: Straub, Christopher
name: Brendel, Philipp
name: Medvedev, Vlad
name: Rosskopf, Andreas
Publisher: name: arXiv
Year: 2025
Subjects: subject: Machine Learning (cs.LG)
subject: Artificial Intelligence (cs.AI)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Computer and information sciences
subject: FOS: Physical sciences

description: We present a novel approach to hard-constrain Neumann boundary conditions in physics-informed neural networks (PINNs) using Fourier feature embeddings. Neumann boundary conditions are used to described critical processes in various application, yet they are more challenging to hard-constrain in PINNs than Dirichlet conditions. Our method employs specific Fourier feature embeddings to directly incorporate Neumann boundary conditions into the neural network's architecture instead of learning them. The embedding can be naturally extended by high frequency modes to better capture high frequency phenomena. We demonstrate the efficacy of our approach through experiments on a diffusion problem, for which our method outperforms existing hard-constraining methods and classical PINNs, particularly in multiscale and high frequency scenarios.
description: 13 pages, 3 figures, 3 tables
Palatini f(R) gravity and Noether symmetry
Creators: name: Roshan, Mahmood
name: Shojai, Fatimah
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We study Palatini f(R) cosmology using Noether symmetry approach for the matter dominated universe. In order to construct a point-like Lagrangian in the flat FRW space time, we use the dynamical equivalence between f(R) gravity and scalar-tensor theories. The existence of Noether symmetry of the cosmological f(R) Lagrangian helps us to find out the form of f(R) and the exact solutions for cosmic scale factor. We show that this symmetry always exist for f(R)~R^n and the Noether constant is a function of the Newton's gravitational constant and the current matter content of the universe.
description: 4 pages,to appear in physics letters B
Algebraic model structures
Creators: name: Riehl, Emily
Publisher: name: arXiv
Year: 2009
Subjects: subject: Category Theory (math.CT)
subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 55U35, 18A32

description: We define a new notion of an algebraic model structure, in which the cofibrations and fibrations are retracts of coalgebras for comonads and algebras for monads, and prove "algebraic" analogs of classical results. Using a modified version of Quillen's small object argument, we show that every cofibrantly generated model structure in the usual sense underlies a cofibrantly generated algebraic model structure. We show how to pass a cofibrantly generated algebraic model structure across an adjunction, and we characterize the algebraic Quillen adjunction that results. We prove that pointwise natural weak factorization systems on diagram categories are cofibrantly generated if the original ones are, and we give an algebraic generalization of the projective model structure. Finally, we prove that certain fundamental comparison maps present in any cofibrantly generated model category are cofibrations when the cofibrations are monomorphisms, a conclusion that does not seem to be provable in the classical, non-algebraic, theory.
description: 51 pages; final journal version; cosmetic changes only
title: A Fluorescent Tracer Study at a Tidal Inlet (Rudee Inlet, Virginia)
Creators: name: Bunch, James W.
Publisher: name: Old Dominion University
publisherIdentifier: https://ror.org/04zjtrb98
publisherIdentifierScheme: ROR
Year: 1969

description: Patterns and approximate rates of littoral transport south of Rudee Inlet. Virginia were investigated with fluorescent tracers. Sand movement was traced under a variety of longshore current and wave conditions. Patterns of tracer dispersal reflected the importance of wave height, breaker angle, and longshore current velocity on modes of littoral transport. A direct relationship between angle of breaker incidence. generated longshore current. and direction of tracer sand movement was found. Onshore offshore paths were taken by tracer material during periods of weak longshore currents and small breaker angles while alongshore paths were followed by tracer material during strong longshore currents and increasing breaker angles.

Drift rates were calculated from tracer analysis. An approximate mean northerly drift rate of 70,000 yds. 3/yr. was determined from calculated drift rates for each test and analysis of swell data.
Noether-Lefschetz theorem with base locus
Creators: name: Brevik, John
name: Nollet, Scott
Publisher: name: arXiv
Year: 2008
Subjects: subject: Algebraic Geometry (math.AG)
subject: FOS: Mathematics
subject: 14C22

description: We compute the class groups of very general normal surfaces in complex projective three-space containing an arbitrary base locus $Z$, thereby extending the classic Noether-Lefschetz theorem (the case when $Z$ is empty). Our method is an adaptation of Griffiths and Harris' degeneration proof, simplified by a cohomology and base change argument. We give applications to computing Picard groups, which generalize several known results.
description: 18 pages, amsart
Magnetic response of noncentrosymmetric superconductor La2C3: Effect of double-gap and spin-orbit interaction
Creators: name: Kadono, R.
name: Hiraishi, M.
name: Miyazaki, M.
name: Satoh, K. H.
name: Takeshita, S.
name: Kuroiwa, S.
name: Saura, S.
name: Akimitsu, J.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: Other Condensed Matter (cond-mat.other)
subject: FOS: Physical sciences

description: The presence of spin-orbit (SO) interaction in a noncentrosymmetric superconductor, La2C3 (T_c~11 K) is demonstrated by muon spin rotation (muSR) in its normal state, where muSR spectra exhibit field-induced weak depolarization due to van Vleck-like local susceptibility. In the mixed state, muon spin relaxation due to inhomogeneity of internal field (sigma_v) exhibits a field dependence that is characterized by a kink, where sigma_v (and hence the superfluid density) is more strongly reduced at lower fields. This is perfectly in line with the presence of a secondary energy gap previously inferred from the temperature dependence of sigma_v, and also consistent with the possible influence of asymmetric deformation of the Fermi surface due to the SO interaction.
description: 4 pages, 4 figures
Constant mean curvature solutions of the Einstein-scalar field constraint equations on asymptotically hyperbolic manifolds
Creators: name: Sakovich, Anna
Publisher: name: arXiv
Year: 2009
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Differential Geometry (math.DG)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: We follow the approach employed by Y. Choquet-Bruhat, J. Isenberg and D. Pollack in the case of closed manifolds and establish existence and non-existence results for the Einstein-scalar field constraint equations on asymptotically hyperbolic manifolds.
description: 15 pages
Psychophysiological correlates of sensation seeking during auditory stimulation
Creators: name: Ridgeway, Doreen G.
Publisher: name: University of British Columbia
Year: 2010

description: Behavioral and physiological responses were monitored while extreme high (n=l6) and low (n=15) scorers on the Sensation Seeking Scale were presented 10 tones at 60, 80, and 100 dB. In general, no compelling behavioral or physiological differences between the groups were found. Initially, there were no differences between the groups on the behavioral variables. The low sensation seeking subjects reported lower verbal ratings of pleasure and higher verbal ratings of stress than did the high sensationsseeking subjects as a result of increased stimulation. Although these results provide support for the hypothesis that high sensation seeking individuals prefer higher levels of stimulation, the interpretation of these data is not that clear-cut since the ratings were done over the blocks. As a result it is not clear whether the subjects are rating their response to the tones, the cummulative effect of isolation, or what. Although a "biological basis" of sensation seeking has been proposed, the present empirical data do not support this notion. Of the number of physiological variables, the only significant physiological group difference to emerge was with vasomotor activity, with the low sensationsseeking subjects being generally more responsive. Although not significant, the high sensation seeking subjects did display the predicted larger skin conductance orienting response on the first presentation of the novel stimuli. The general pattern of increased skin conductance, heart rate acceleration, and vasoconstriction in response to stimulation suggests that the experimental procedure had similar effects on "both groups. Further research with vasomotor activity may clarify the physiological basis of the sensation seeking dimension; however, at this point, the "biological "basis of sensation seeking remains unclear.
Diffractive Vector Meson Photoproduction from Dual String Theory
Creators: name: Freund, Peter G. O.
name: Nastase, Horatiu
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We study diffractive vector meson photoproduction using string theory via AdS/CFT. The large $s$ behavior of the cross sections for the scattering of the vector meson $V$ on a proton is dominated by the soft Pomeron, $σ_V\sim s^{2ε-2α'_P/B}$, where from the string theory model of \cite{nastase2}, $ε$ is approximately 1/7 below 10 GeV, and 1/11 for higher, but still sub-Froissart, energies. This is due to the production of black holes in the dual gravity. In $ϕ$-photoproduction the mesonic Regge poles do not contribute, so that we deal with a pure Pomeron contribution. This allows for an experimental test. At the gauge theory "Planck scale" of about 1-2 GeV, the ratios of the soft Pomeron contributions to the photoproduction cross-sections of different vector mesons involve not only the obvious quark model factors, but also the Boltzmann factors $e^{-4 M_V/T_0}$, with $T_0$ the temperature of the dual black hole. The presence of these factors is confirmed in the experimental data for $ρ, ω, ϕ, J/ψ,$ and $ψ(2S)$ photoproduction and is compatible with the meager $Υ$ photoproduction data. Throughout, we use vector meson dominance, and from the data we obtain $T_0$ of about $1.3 GeV$, i.e. the gauge theory "Planck scale," as expected. The ratio of the experimental soft Pomeron onset scale $\hat{E}_R\sim 9$ GeV and of the gauge theory Planck scale, $T_0 \sim 1.3$ GeV conforms to the theoretical prediction of $N_c^2/N_c^{1/4}$.
description: 17 pages, 1 figure, latex
Nonlocal Patch-Based Fully-Connected Tensor Network Decomposition for Remote Sensing Image Inpainting
Creators: name: Zheng, Wen-Jie
name: Zhao, Xi-Le
name: Zheng, Yu-Bang
name: Pang, Zhi-Feng
Publisher: name: arXiv
Year: 2021
Subjects: subject: Computer Vision and Pattern Recognition (cs.CV)
subject: FOS: Computer and information sciences

description: Remote sensing image (RSI) inpainting plays an important role in real applications. Recently, fully-connected tensor network (FCTN) decomposition has been shown the remarkable ability to fully characterize the global correlation. Considering the global correlation and the nonlocal self-similarity (NSS) of RSIs, this paper introduces the FCTN decomposition to the whole RSI and its NSS groups, and proposes a novel nonlocal patch-based FCTN (NL-FCTN) decomposition for RSI inpainting. Different from other nonlocal patch-based methods, the NL-FCTN decomposition-based method, which increases tensor order by stacking similar small-sized patches to NSS groups, cleverly leverages the remarkable ability of FCTN decomposition to deal with higher-order tensors. Besides, we propose an efficient proximal alternating minimization-based algorithm to solve the proposed NL-FCTN decomposition-based model with a theoretical convergence guarantee. Extensive experiments on RSIs demonstrate that the proposed method achieves the state-of-the-art inpainting performance in all compared methods.
The BLAST 250-micron selected galaxy population in GOODS-South
Creators: name: Dunlop, J. S.
name: Ade, P. A. R.
name: Bock, J. J.
name: Chapin, E. L.
name: Cirasuolo, M.
name: Coppin, K. E. K.
name: Devlin, M. J.
name: Griffin, M.
name: Greve, T. R.
name: Gundersen, J. O.
name: Halpern, M.
name: Hargrave, P. C.
name: Hughes, D. H.
name: Ivison, R. J.
name: Klein, J.
name: Kovacs, A.
name: Marsden, G.
name: Mauskopf, P.
name: Netterfield, C. B.
name: Olmi, L.
name: Pascale, E.
name: Patanchon, G.
name: Rex, M.
name: Scott, D.
name: Semisch, C.
name: Smail, I.
name: Targett, T. A.
name: Thomas, N.
name: Truch, M. D. P.
name: Tucker, C.
name: Tucker, G. S.
name: Viero, M. P.
name: Walter, F.
name: Wardlow, J. L.
name: Weiss, A.
name: Wiebe, D. V.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: We identify and investigate the nature of the 20 brightest 250-micron sources detected by the BLAST within the central 150 sq. arcmin of the GOODS-South field. Aided by the available deep VLA radio imaging, reaching S_1.4 = 30 micro-Jy, we have identified radio counterparts for 17/20 of the 250-micron sources. The resulting enhanced positional accuracy of ~1 arcsec has then allowed us to exploit the deep multi-frequency imaging of GOODS-South to establish secure galaxy counterparts for the 17 radio-identified sources, and plausible galaxy candidates for the 3 radio-unidentified sources. Confusion is a serious issue for this deep BLAST 250-micron survey, due to the large size of the beam. Nevertheless, we argue that our chosen counterparts are significant, and often dominant contributors to the measured BLAST flux densities. For all of these 20 galaxies we have been able to determine spectroscopic (8) or photometric (12) redshifts. The result is the first `complete' redshift distribution for a deep 250-micron selected galaxy sample. This reveals that 250-micron surveys reaching detection limits of ~30 mJy contain not only low-redshift spirals/LIRGs, but also the extreme z~2 dust-enshrouded starburst galaxies previously discovered at sub-millimetre wavelengths. Based on their IRAC colours, we find that virtually all of the BLAST galaxy identifications appear better described as analogues of the M82 starburst galaxy, or Sc star-forming discs rather than highly obscured ULIRGs. Inspection of the LABOCA 870-micron imaging of the GOODS-South field yields detections of 7/11 of the z>1 BLAST sources, and reveals 250/870 flux-density ratios consistent with a standard 40K modified black-body fit with a dust emissivity index beta=1.5.
description: 29 pages, submitted to MNRAS
Ekpyrotic and Cyclic Cosmology
Creators: name: Lehners, Jean-Luc
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Ekpyrotic and cyclic cosmologies provide theories of the very early and of the very late universe. In these models, the big bang is described as a collision of branes - and thus the big bang is not the beginning of time. Before the big bang, there is an ekpyrotic phase with equation of state w=P/rho >> 1 (where P is the average pressure and rho the average energy density) during which the universe slowly contracts. This phase resolves the standard cosmological puzzles and generates a nearly scale-invariant spectrum of cosmological perturbations containing a significant non-gaussian component. At the same time it produces small-amplitude gravitational waves with a blue spectrum. The dark energy dominating the present-day cosmological evolution is reinterpreted as a small attractive force between our brane and a parallel one. This force eventually induces a new ekpyrotic phase and a new brane collision, leading to the idea of a cyclic universe. This review discusses the detailed properties of these models, their embedding in M-theory and their viability, with an emphasis on open issues and observational signatures.
description: 79 pages, 12 figures, invited review to be published in Phys. Rept. Non-gaussianity section updated and generalized
Quantum Proofs for Classical Theorems
Creators: name: Drucker, Andrew
name: de Wolf, Ronald
Publisher: name: arXiv
Year: 2009
Subjects: subject: Quantum Physics (quant-ph)
subject: Computational Complexity (cs.CC)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Alongside the development of quantum algorithms and quantum complexity theory in recent years, quantum techniques have also proved instrumental in obtaining results in classical (non-quantum) areas. In this paper we survey these results and the quantum toolbox they use.
description: 50 pages LaTeX. Updated based on journal version; the journal version is open-access and has nicer typesetting (http://theoryofcomputing.org/articles/gs002/)
Riuscirà la ricerca scientifica a sopravvivere all'Intelligenza Artificiale?
Creators: name: Boldi, Paolo
Publisher: name: Zenodo
Year: 2024

description: Presentazione tenuta durante il seminario: Intelligenza artificiale e ricerca scientifica minacce ed opportunità in un contesto di scienza aperta, all'interno di un ciclo di incontri dal titolo:

Può ancora esistere una buona comunicazione scientifica? incontri sugli aspetti etici e pragmatici della scienza in un contesto accademico ipercompetitivo
Multigraded Factorial Rings and Fano varieties with torus action
Creators: name: Hausen, Juergen
name: Herppich, Elaine
name: Süß, Hendrik
Publisher: name: arXiv
Year: 2009
Subjects: subject: Algebraic Geometry (math.AG)
subject: Commutative Algebra (math.AC)
subject: FOS: Mathematics
subject: 13A02, 13F15, 14J45

description: In a first result, we describe all finitely generated factorial algebras over an algebraically closed field of characteristic zero that come with an effective multigrading of complexity one by means of generators and relations. This enables us to construct systematically varieties with free divisor class group and a complexity one torus action via their Cox rings. For the Fano varieties of this type that have a free divisor class group of rank one, we provide explicit bounds for the number of possible deformation types depending on the dimension and the index of the Picard group in the divisor class group. As a consequence, one can produce classification lists for fixed dimension and Picard index. We carry this out expemplarily in the following cases. There are 15 non-toric surfaces with Picard index at most six. Moreover, there are 116 non-toric threefolds with Picard index at most two; nine of them are locally factorial, i.e. of Picard index one, and among these one is smooth, six have canonical singularities and two have non-canonical singularities. Finally, there are 67 non-toric locally factorial fourfolds and two one-dimensional families of non-toric locally factorial fourfolds. In all cases, we list the Cox rings explicitly.
description: several corrections, 30 pages, to appear in Doc. Math
A massive binary black-hole system in OJ287 and a test of general relativity
Creators: name: Valtonen, M. J.
name: Lehto, H. J.
name: Nilsson, K.
name: Heidt, J.
name: Takalo, L. O.
name: Sillanpää, A.
name: Villforth, C.
name: Kidger, M.
name: Poyner, G.
name: Pursimo, T.
name: Zola, S.
name: Wu, J. -H.
name: Zhou, X.
name: Sadakane, K.
name: Drozdz, M.
name: Koziel, D.
name: Marchev, D.
name: Ogloza, W.
name: Porowski, C.
name: Siwak, M.
name: Stachowski, G.
name: Winiarski, M.
name: Hentunen, V. -P.
name: Nissinen, M.
name: Liakos, A.
name: Dogru, S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ287. This quasar shows quasi-periodic optical outbursts at 12 yr intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened twenty days later.
description: 14 pages, 3 figures, published in Nature
The impact of human-biometeorological factors on perceived thermal comfort in urban public places
Creators: name: Maras, Isabell
name: Schmidt, Teresa
name: Paas, Bastian
name: Ziefle, Martina
name: Schneider, Christoph
Publisher: name: Humboldt-Universität zu Berlin
Year: 2016
Subjects: subject: thermal stress
subject: urban public spaces
subject: urban climate
subject: field study
subject: psychophysics measurements
subject: thermal comfort
subject: 910 Geografie und Reisen

description: Die Zweitveröffentlichung der Publikation wurde durch Studierende des Projektseminars "Open Access Publizieren an der HU" im Sommersemester 2017 betreut. Nachgenutzt gemäß den CC-Bestimmungen des Lizenzgebers bzw. einer im Dokument selbst enthaltenen CC-Lizenz.
description: For the understanding of the impact of meteorological stressors on human perceptions of thermal comfort, it is essential to examine in detail the joint variability of atmospheric conditions and human perception. We designed an interdisciplinary experimental setup to generate data of both human-biometeorological and individual human perception at two different urban public places in the city of Aachen, Germany. Meteorological measurements at the human-biometeorological standard height of 1.1 m a.g.l. were taken during typical winter weather situations as well as extreme summer weather situations to analyze potentially seasonal effects. Pedestrians and tourists at the study site were selected as participants for face-to-face questionnaire-based interviews. We took measurements and held interviews between 10:00 h and 17:00 h (CEST/CET) to record the daytime agreement/deviations at different inner urban measurement locations. Based on an overall physical approach of thermal load, UTCI (Universal Thermal Climate Index) values are calculated. A maximum of +34.1 °C for summertime and a minimum of +2.6 °C for wintertime could be found. The meteorological parameters of air temperature (Ta), mean radiant temperature (Tmrt) and vapor pressure (VP) are compared with data perceived by the persons interviewed. In winter, Ta shows a significant relation to the overall weather perception (r = 0.28; p < 0.05) while the overall comfort of the participants is significantly related to perceived solar heat (r = 0.27; p < 0.5) as well as to perceived Ta (r = 0.4; p < 0.002). Quite different resulting patterns occurred for the summer campaign. None of the physical variables significantly affected the weather perception. Only the perceived Ta revealed a significant relation to the overall weather perception (r = 0.27; p < 0.002).
First-principles quantum dynamics for fermions: Application to molecular dissociation
Creators: name: Ogren, M.
name: Kheruntsyan, K. V.
name: Corney, J. F.
Publisher: name: arXiv
Year: 2009
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: We demonstrate that the quantum dynamics of a many-body Fermi-Bose system can be simulated using a Gaussian phase-space representation method. In particular, we consider the application of the mixed fermion-boson model to ultracold quantum gases and simulate the dynamics of dissociation of a Bose-Einstein condensate of bosonic dimers into pairs of fermionic atoms. We quantify deviations of atom-atom pair correlations from Wick's factorization scheme, and show that atom-molecule and molecule-molecule correlations grow with time, in clear departures from pairing mean-field theories. As a first-principles approach, the method provides benchmarking of approximate approaches and can be used to validate dynamical probes for characterizing strongly correlated phases of fermionic systems.
description: Final published version
Creed and credibility : aesthetic consequences of faith in the fiction of Graham Greene
Creators: name: Newman, Gillian
Publisher: name: University of British Columbia
Year: 2010

description: Beliefs a writer holds dear clearly influence the selection and treatment of ideas in his fiction: the purpose of this study is to examine the effect of Greene's religious sensibility on theme, mode, and characterization in a representative selection of his novels. From the late 30's to the early 50's, Greene's novels deal with dilemmas of faith that beset his Catholic characters; In The Power and the Glory (1940) he achieves startling and dramatic effects from the religious paradigms at the core of the novel. After the contentious success of the so-called 'Catholic' trilogy, The End of the Affair (1951) illustrates the difficulties to which an overzealous concern with specific issues of doctrine can lead when religious premises conflict directly with artistic requirements. From this point on, the perspective of Greene's novels is less and less specifically religious as he turns to considerations of a wider moral and social kind. In The Quiet American (1955), Greene explores the more existentialist questions of the freedom of choice and the responsibility of individual existence; however, his long preoccupation with Catholicism still intrudes in ways detrimental to the established development of the fiction. With the publication of The Comedians (1966) it is evident that Greene has moved even further away from the crises of faith that hounded his earlier characters as he focuses on an uncommitted anti-hero surrounded by an assortment of ideologies and forms of commitment. The development in Greene's religious vision has made him see and respond to the world of experience differently so that the themes and techniques of his fiction have changed accordingly. The broadening of his religious concerns has resulted in fiction that is less doctrinaire, less controversial, and perhaps more accessible. The negative presentation of the necessity of any form of faith through an anti-heroic central character has meant some loss of the intensity he could achieve as a novelist of urgent spiritual conflicts in his 'Catholic' period: it has also meant he could transcend specific issues of doctrine that could be so binding on his literary imagination, enabling him to create a more detached and witty representation of his broader religious ideas.
Scaling of the atmosphere of self-avoiding walks
Creators: name: Owczarek, A. L.
name: Prellberg, T.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Mathematical Physics (math-ph)
subject: Combinatorics (math.CO)
subject: FOS: Physical sciences
subject: FOS: Mathematics

description: The number of free sites next to the end of a self-avoiding walk is known as the atmosphere. The average atmosphere can be related to the number of configurations. Here we study the distribution of atmospheres as a function of length and how the number of walks of fixed atmosphere scale. Certain bounds on these numbers can be proved. We use Monte Carlo estimates to verify our conjectures. Of particular interest are walks that have zero atmosphere, which are known as trapped. We demonstrate that these walks scale in the same way as the full set of self-avoiding walks, barring an overall constant factor.
Thin accretion disks onto brane world black holes
Creators: name: Pun, C. S. J.
name: Kovacs, Z.
name: Harko, T.
Publisher: name: arXiv
Year: 2008
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: The braneworld description of our universe entails a large extra dimension and a fundamental scale of gravity that might be lower by several orders of magnitude as compared to the Planck scale. An interesting consequence of the braneworld scenario is in the nature of the vacuum solutions of the brane gravitational field equations, with properties quite distinct as compared to the standard black hole solutions of general relativity. One possibility of observationally discriminating between different types of black holes is the study of the emission properties of the accretion disks. In the present paper we obtain the energy flux, the emission spectrum and accretion efficiency from the accretion disks around several classes of static and rotating brane world black holes, and we compare them to the general relativistic case. Particular signatures can appear in the electromagnetic spectrum, thus leading to the possibility of directly testing extra-dimensional physical models by using astrophysical observations of the emission spectra from accretion disks.
description: 37 pages, 14 figures, accepted for publication in PRD
Lower semicontinuous functionals for Almgren's multiple valued functions
Creators: name: De Lellis, Camillo
name: Focardi, Matteo
name: Spadaro, Emanuele Nunzio
Publisher: name: arXiv
Year: 2009
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics
subject: 49J45, 49Q20

description: We consider general integral functionals on the Sobolev spaces of multiple valued functions, introduced by Almgren. We characterize the semicontinuous ones and recover earlier results of Mattila as a particular case. Moreover, we answer positively to one of the questions raised by Mattila in the same paper.
description: 19 pages; [v2] minor changes for publication
title: Teaching and learning technology concepts in secondary schools: A study of psychological factors affecting pupil performance
Creators: name: Doherty, Martin
Publisher: name: University of Glasgow
Year: 1999

description: This thesis reports the findings of a study that attempted to apply an information processing model to assess and improve the teaching and learning in a secondary school technology course. Two cognitive factors believed to have an important influence on pupil performance were measured, namely: working memory capacity (X-space) and field-dependence/independence (F.IND/F.D). The research involved 71 pupils form St. Stephen's High School in Port Glasgow and a 105 pupils from St. Columba's High School in Clydebank whose ages ranged from 13 to 14 years. Initially, the working memory capacities and field-dependent/independent learning styles of the sample from St. Stephen's High School were ascertained using a new version of the digit span test and the hidden figure test (H.F.T) respectively. These tests had been developed at the Centre for Science Education in the University of Glasgow. The results of the digit span test divided the sample into groups of low, intermediate and high working memory capacity (X=5, X=6 and X=7). The pupil's learning style categories were established from the hidden figure test, i.e. field-dependent, field-intermediate and field-independent. A technology course that focussed on gear and belt driven mechanisms was then taught to the pupils over a period of about 4 weeks. On completion of the course a test was given with questions that had been assessed for the demand (Z) which they placed on the pupils X-capacity. The information processing model was applied to the mechanisms course so that problem areas might be identified and eradicated. It was discovered that a substantial number of changes were required to remove the material thought to have caused difficulties for the pupils (noise) and to improve the general quality (signal) of the course. After considering the amount of modifications necessary it was decided that a completely new course on mechanisms had to be written. This was presented to the pupils from St. Columba's High School after the two psychological factors had been measured. A comparison of the results from both schools was then made in an effort to assess the effectiveness of the new technology course and to test the hypotheses that working memory and field-dependence/independence were related to pupil performance. An analysis of the psychological factors and pupil performance in the mechanisms tests from both schools suggested that a relationship existed between X-capacity and the Z- demand of the technology questions. It appeared that pupils who were considered to be field-dependent had inefficient memory processes and performed less effectively in the mechanisms tests. The findings implied that field-independent, high X-capacity pupils were the most successful of all the candidates in answering questions of greater complexity. Furthermore, the application of the information processing model seemed to have helped in improving pupil attainment in technology concepts.
Determining role of Krein signature for 3D Arnold tongues of oscillatory dynamos
Creators: name: Kirillov, Oleg N.
name: Guenther, Uwe
name: Stefani, Frank
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mathematical Physics (math-ph)
subject: Astrophysics (astro-ph)
subject: Dynamical Systems (math.DS)
subject: Geophysics (physics.geo-ph)
subject: FOS: Physical sciences
subject: FOS: Mathematics
subject: 86A25; 46C20; 47A55

description: Using a homotopic family of boundary eigenvalue problems for the mean-field $α^2$-dynamo with helical turbulence parameter $α(r)=α_0+γΔα(r)$ and homotopy parameter $β\in [0,1]$, we show that the underlying network of diabolical points for Dirichlet (idealized, $β=0$) boundary conditions substantially determines the choreography of eigenvalues and thus the character of the dynamo instability for Robin (physically realistic, $β=1$) boundary conditions. In the $(α_0,β,γ)-$space the Arnold tongues of oscillatory solutions at $β=1$ end up at the diabolical points for $β=0$. In the vicinity of the diabolical points the space orientation of the 3D tongues, which are cones in first-order approximation, is determined by the Krein signature of the modes involved in the diabolical crossings at the apexes of the cones. The Krein space induced geometry of the resonance zones explains the subtleties in finding $α$-profiles leading to spectral exceptional points, which are important ingredients in recent theories of polarity reversals of the geomagnetic field.
description: 4 pages, 3 figures, presented at the GAMM 2008, Bremen, Germany Introduction extended, refs added
Resonance energy of the barKNN-piYN system
Creators: name: Ikeda, Yoichi
name: Sato, Toru
Publisher: name: arXiv
Year: 2008
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: The resonance energies of strange dibaryons are investigated with the use of the \bar{K}NN-πY N coupled-channels Faddeev equation. It is found that the pole positions of the predicted three-body amplitudes are significantly modified when the three-body coupled-channels dynamics is approximated, as is done in the literature, by the effective two-body \bar{K}N interactions.
description: 14 pages, 5 figures
$L$-valley electron $g$ factor in bulk GaAs and AlAs
Creators: name: Shen, K.
name: Weng, M. Q.
name: Wu, M. W.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We study the Landé $g$-factor of conduction electrons in the $L$-valley of bulk GaAs and AlAs by using a three-band $\mathbf{k}\cdot\mathbf{p}$ model together with the tight-binding model. We find that the $L$-valley $g$-factor is highly anisotropic, and can be characterized by two components, $g_{\perp}$ and $g_{\|}$. $g_{\perp}$ is close to the free electron Landé factor but $g_{\|}$ is strongly affected by the remote bands. The contribution from remote bands on $g_{\|}$ depends on how the remote bands are treated. However, when the magnetic field is in the Voigt configuration, which is widely used in the experiments, different models give almost identical $g$-factor.
description: 4 pages, 1 figure, To be published in J. App. Phys. 104, 2008
Losses in Superconductors under Non-Sinusoidal Currents and Magnetic Fields
Creators: name: Sokolovsky, Vladimir
name: Meerovich, Victor
name: Spektor, Marat
name: Levin, George
name: Vajda, Istvan
Publisher: name: arXiv
Year: 2008
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Study of AC losses in superconducting wires and tapes is usually restricted by consideration of applied sinusoidal currents and/or magnetic fields. However, currents in electric power systems contain a wide variety of harmonics. The currents become strongly non-sinusoidal at the operation of converters, non-linear reactors, and during transient and overload conditions. We report the results of the analysis of the influence of higher harmonics of the current and magnetic field on AC losses in superconducting slabs, strips and coated conductors. Analytical expressions are obtained in the framework of Bean's critical state model; the power law voltage-current characteristics are treated numerically. It is shown that the contribution of higher harmonics to AC losses in superconducting elements can be tens times larger than in normal metals and the 5% harmonic can increases the losses by up to 20%.
description: paper reported at Applied Superconductivity Conference ASC-2008
Magnetic Moment Generation from non-minimal couplings in a scenario with Lorentz-Symmetry Violation
Creators: name: Belich, H.
name: Colatto, L. P.
name: Costa-Soares, T.
name: Helayël-Neto, J. A.
name: Orlando, M. T. D.
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: This paper deals with situations that illustrate how the violation of Lorentz symmetry in the gauge sector may contribute to magnetic moment generation of massive neutral particles with spin-1/2 and spin-1. The procedure we adopt here is based on Relativistic Quantum Mechanics. We work out the non-relativistic regime that follows from the wave equation corresponding to a certain particle coupled to an external electromagnetic field and a background that accounts for the Lorentz symmetry violation, and we read thereby the magnetic dipole moment operator for the particle under consideration.We keep track of the parameters that govern the non-minimal electromagnetic coupling and the breaking of Lorentz symmetry in the expressions we get for the magnetic moments in the different cases we contemplate. Our claim is that the tiny magnetic dipole moment of truly elementary neutral particles might signal Lorentz symmetry violation.
description: 9 pages, revtex
Study of Bc -> BP,BV Decays with QCD Factorization
Creators: name: Sun, Junfeng
name: Yang, Yueling
name: Du, Wenjie
name: Ma, Huilan
Publisher: name: arXiv
Year: 2008
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The Bc -> BP,BV decays are studied with the QCD factorization approach (where P and V denote pseudoscalar and vector mesons, respectively). Considering the contributions of both current-current and penguin operators, the amplitudes of branching ratios are estimated at the leading approximation. We find that the contributions of the penguin operators are very small due to the serious suppression by the CKM elements. The most promising decay modes are Bc -> Bs Pi, Bs rho, which might be easily detected at hadron colliders.
description: revtex4; Published Fri Jun 6, 2008
Onsager reciprocity in premelting solids
Creators: name: Peppin, S. S. L.
name: Spannuth, M.
name: Wettlaufer, J. S.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The diffusive motion of colloidal particles dispersed in a premelting solid is analyzed within the framework of irreversible thermodynamics. We determine the mass diffusion coefficient, thermal diffusion coefficient and Soret coefficient of the particles in the dilute limit, and find good agreement with experimental data. In contrast to liquid suspensions, the unique nature of premelting solids allows us to derive an expression for the Dufour coefficient and independently verify the Onsager reciprocal relation coupling diffusion to the flow of heat.
description: 4 pages, 2 figures, 1 appendix
Geometric decompositions and local bases for spaces of finite element differential forms
Creators: name: Arnold, Douglas N.
name: Falk, Richard S.
name: Winther, Ragnar
Publisher: name: arXiv
Year: 2008
Subjects: subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics
subject: 65N30

description: We study the two primary families of spaces of finite element differential forms with respect to a simplicial mesh in any number of space dimensions. These spaces are generalizations of the classical finite element spaces for vector fields, frequently referred to as Raviart-Thomas, Brezzi-Douglas-Marini, and Nedelec spaces. In the present paper, we derive geometric decompositions of these spaces which lead directly to explicit local bases for them, generalizing the Bernstein basis for ordinary Lagrange finite elements. The approach applies to both families of finite element spaces, for arbitrary polynomial degree, arbitrary order of the differential forms, and an arbitrary simplicial triangulation in any number of space dimensions. A prominent role in the construction is played by the notion of a consistent family of extension operators, which expresses in an abstract framework a sufficient condition for deriving a geometric decomposition of a finite element space leading to a local basis.
description: 25 pages, 2 figures, submitted to Computer Methods in Applied Mechanics and Engineering
The targum (1971:Sept. 10 - 1971:Sept. 30)
Creators: name: No Name Supplied
Publisher: name: Targum Association
Year: 1971

description: Some University historians indicate that the Targum was first published as an annual in 1867, but of this we have no extant evidence. In January 1869, the Targum as we now know it, made its appearance as a monthly paper that concerned itself with student “literary contributions” and college news as well as serving as a vehicle for bringing news to alumni and the general public. The newspaper, which originally was for sale, varied in frequency over the years as did its title (The Targum, Rutgers Targum, Rutgers Daily Targum, and Daily Targum). The newspaper has continuously been published since 1869 with the exception of 19 months during the second world war, between February 1944 and October 1945. The Targum was published by the students of Rutgers College, and later Rutgers University—New Brunswick represented through the years as the Targum Association, Rutgers Targum Association, and Rutgers College Targum. As a student organization, the Targum operated under the oversight of the dean of students and student government but in October 1980, the Targum became an independent college paper.
Nuclear medium modification of the F2 structure function
Creators: name: Athar, M. Sajjad
name: Simo, I. Ruiz
name: Vacas, M. J. Vicente
Publisher: name: arXiv
Year: 2009
Subjects: subject: Nuclear Theory (nucl-th)
subject: FOS: Physical sciences

description: We study the nuclear effects in the electromagnetic structure function F2(x,Q^2) in nuclei in the deep inelastic lepton nucleus scattering process by taking into account Fermi motion, binding, pion and rho meson cloud contributions. Calculations have been done in a local density approximation using relativistic nuclear spectral functions which include nucleon correlations for nuclear matter. The ratios over deuteron structure function are obtained and compared with the recent JLAB results for light nuclei with special attention to the slope of the x distributions. This magnitude shows a non trivial A dependence and it is insensitive to possible normalization uncertainties. The results have also been compared with some of the older experiments using intermediate mass nuclei.
description: 19 pages, 8 figures. This version matches accepted version to be published in Nuclear Physics A
Understanding individual human mobility patterns
Creators: name: Gonzalez, M. C.
name: Hidalgo, C. A.
name: Barabasi, A. -L.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Physics and Society (physics.soc-ph)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Computers and Society (cs.CY)
subject: Biological Physics (physics.bio-ph)
subject: FOS: Physical sciences
subject: FOS: Computer and information sciences

description: Despite their importance for urban planning, traffic forecasting, and the spread of biological and mobile viruses, our understanding of the basic laws governing human motion remains limited thanks to the lack of tools to monitor the time resolved location of individuals. Here we study the trajectory of 100,000 anonymized mobile phone users whose position is tracked for a six month period. We find that in contrast with the random trajectories predicted by the prevailing Levy flight and random walk models, human trajectories show a high degree of temporal and spatial regularity, each individual being characterized by a time independent characteristic length scale and a significant probability to return to a few highly frequented locations. After correcting for differences in travel distances and the inherent anisotropy of each trajectory, the individual travel patterns collapse into a single spatial probability distribution, indicating that despite the diversity of their travel history, humans follow simple reproducible patterns. This inherent similarity in travel patterns could impact all phenomena driven by human mobility, from epidemic prevention to emergency response, urban planning and agent based modeling.
description: Supporting Webpage: http://www.nd.edu/~mgonza16/Marta'sHomepage_files/nature2008/research.html