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January 2009 arXiv papers — page 39

Showing 3,8013,900 of 4,902 papers

  1. Alejandro Corichi

    Black holes in equilibrium and the counting of their entropy within Loop Quantum Gravity are reviewed. In particular, we focus on the conceptual setting of the formalism, briefly summarizing the main results of the classical formalism and its quantization. We then focus on recent results for small, Planck scale, black holes, where new structures have been sh

  2. Parampreet Singh

    We discuss the way non-perturbative quantization of cosmological spacetimes in loop quantum cosmology provides insights on the physics of Planck scale and the resolution of big bang singularity. In recent years, rigorous examination of mathematical and physical aspects of the quantum theory has led to a consistent quantization which is consistent and physica

  3. Y. Xia, D. Qian, L. Wray, D. Hsieh

    We report the first photoemission study of Fe1+xTe - the host compound of the newly discovered iron-chalcogenide superconductors. Our results reveal a pair of nearly electron- hole compensated Fermi pockets, strong Fermi velocity renormalization and an absence of a spin-density-wave gap. A shadow hole pocket is observed at the "X"-point of the Brillo

  4. E. Gorsky

    To every tree we associate a filtered cochain complex. Its cohomology and the corresponding spectral sequence have clear combinatorial description. If a tree is the Dynkin diagram of a simple plane curve singularity, the graded Euler characteristic of this complex coincides with the Alexander polynomial of the link. In this case we also point the relation to

  5. A. Reimer, O. Reimer

    We explore the ability of high energy observations to constrain orbital parameters of long period massive binary systems by means of an inverse Compton model acting in colliding wind environments. This is particular relevant for (very) long period binaries where orbital parameters are often poorly known from conventional methods, as is the case e.g. for the

  6. R. H. D. Corbet, J. J. M. in 't Zand, A. M. Levine, F. E. Marshall

    We present observations of the 9.8 s X-ray pulsar XTE J1859+083 made with the ASM and PCA on board RXTE, and the WFC on board BeppoSAX. The ASM data cover a 12 year time interval and show that an extended outburst occurred between approximately MJD 50,250 and 50,460 (1996 June 16 to 1997 January 12). The ASM data excluding this outburst interval suggest a po

  7. Stefano Forte, Guido Altarelli, Richard D. Ball

    We review the current status of small x resummation of evolution of parton distributions and of deep-inelastic coefficient functions. We show that the resummed perturbative expansion is stable, robust upon different treatments of subleading terms, and that it matches smoothly to the unresummed perturbative expansions, with corrections which are of the same o

  8. Gavin Brown, Alexander Kasprzyk, Daniel Ryder

    The classification of minimal rational surfaces and the birational links between them by Iskovskikh, Manin and others is a well-known subject in the theory of algebraic surfaces. We explain algorithms that realise links of type II between minimal del Pezzo surfaces, one of the major classes of birational links, and we describe briefly how this fits into a la

  9. Olivier Arcizet, Rémi Rivière, Albert Schliesser, Tobias J. Kippenberg

    We present the optical and mechanical properties of high-Q fused silica microtoroidal resonators at cryogenic temperatures (down to 1.6 K). A thermally induced optical multistability is observed and theoretically described; it serves to characterize quantitatively the static heating induced by light absorption. Moreover the influence of structural defect sta

  10. Jeffrey Brown

    We prove a conjecture of Artur Elezi in a generalized form suggested by Givental. Namely, our main result relates genus-0 Gromov--Witten invariants of a bundle space with such invariants of the base, provided that the fiber is a toric manifold. When the base is the point, a new proof of mirror theorems by A. Givental and by H. Iritani for toric manifolds is

  11. Florentin Smarandache

    In this paper we present the N-norms/N-conorms in neutrosophic logic and set as extensions of T-norms/T-conorms in fuzzy logic and set. Also, as an extension of the Intuitionistic Fuzzy Topology we present the Neutrosophic Topologies.

  12. Dae San Kim

    In this paper, we construct eight infinite families of binary linear codes associated with double cosets with respect to certain maximal parabolic subgroup of the special orthogonal group $SO^-(2n,2^r)$. Then we obtain four infinite families of recursive formulas for the power moments of Kloosterman sums and four those of 2-dimensional Kloosterman sums in te

  13. N. Kains, A. Cassan, K. Horne, M. D. Albrow

    We outline a method for fitting binary-lens caustic-crossing microlensing events based on the alternative model parameterisation proposed and detailed in Cassan (2008). As an illustration of our methodology, we present an analysis of OGLE-2007-BLG-472, a double-peaked Galactic microlensing event with a source crossing the whole caustic structure in less than

  14. F. Massaro, P. Giommi, G. Tosti, A. Cassetti

    BL Lacs are an enigmatic class of active galactic nuclei (AGNs), characterized by the non-thermal continuum typically attributed to synchrotron and inverse Compton emission. Depending on the frequency location of the maxima of these components, they are subdivided into three subclasses LBLs, IBLs, and HBLs. We present the results of a set of observations of

  15. Elena Braverman, Sergey Zhukovskiy

    We study delay-independent stability in nonlinear models with a distributed delay which have a positive equilibrium. Such models frequently occur in population dynamics and other applications. In particular, we construct a relevant difference equation such that its stability implies stability of the equation with a distributed delay and a finite memory. This

  16. J. L. Bohn, M. Cavagnero, C. Ticknor

    We investigate the scattering cross section of aligned dipolar molecules in low-temperature gases. Over a wide range of collision energies relevant to contemporary experiments, the cross section declines in inverse proportion to the collision speed, and is given nearly exactly by a simple semiclassical formula. At yet lower energies, the cross section become

  17. David K. Rollins

    A modified Burgers vortex is considered where the vortex lines are convected toward the y axis and stretched along the y axis. Exact solutions are found for a particular time dependent flow parameter.

  18. Harvey R. Brown

    Valentini [arXiv:0811.0810] has recently defended the de Broglie-Bohm pilot-wave version of quantum theory from the claim that it is essentially Everett theory encumbered with the redundant postulation of point particles. In this note, Valentini's central arguments are questioned.

  19. Leonid Berezansky, Elena Braverman, Alexander Domoshnitsky

    For the delay differential equations $$ \ddot{x}(t) +a(t)\dot{x}(g(t))+b(t)x(h(t))=0, g(t)\leq t, h(t)\leq t, $$ and $$ \ddot{x}(t) +a(t)\dot{x}(t)+b(t)x(t)+a_1(t)\dot{x}(g(t))+b_1(t)x(h(t))=0 $$ explicit exponential stability conditions are obtained.

  20. Yu. B. Ivanov, D. N. Voskresensky

    A new nonlocal form of the off-shell kinetic equation is derived. While being equivalent to the Kadanoff--Baym and Botermans--Malfliet formulations in the range of formal applicability, it has certain advantages beyond this range. It possesses more accurate conservation laws for Noether quantities than those in the Botermans--Malfliet formulation. At the sam

  21. Maurice de Gosson, Franz Luef

    We discuss the relevance to deformation quantization of Feichtinger's modulation spaces, especially of the weighted Sjoestrand classes. These function spaces are good classes of symbols of pseudo-differential operators (observables). They have a widespread use in time-frequency analysis and related topics, but are not very well-known in physics. It turns

  22. Manfred K Warmuth, Dima Kuzmin

    One of the main concepts in quantum physics is a density matrix, which is a symmetric positive definite matrix of trace one. Finite probability distributions can be seen as a special case when the density matrix is restricted to be diagonal. We develop a probability calculus based on these more general distributions that includes definitions of joints, condi

  23. Laurent Nottale

    We have recently proposed a new general concept of macroscopic quantum-type experiment. It amounts to transform a classical fluid into a quantum-type fluid by the application of a quantum-like potential, either directly in a stationary configuration, or through a retro-active loop to simulate the time evolution. In this framework, the amplitude of the quantu

  24. Hoshang Heydari

    We construct quantum gates entanglers for different classes of multipartite states. In particular we construct entangler operators for W and GHZ classes of multipartite states based on the construction of the concurrence classes. We also in detail discuss these two classes of the quantum gates entanglers for three-partite states.

  25. P. Haensel, J. L. Zdunik, M. Bejger, J. M. Lattimer

    We calculate Keplerian (mass shedding) configurations of rigidly rotating neutron stars and quark stars with crusts. We check the validity of empirical formula for Keplerian frequency, f_K, proposed by Lattimer & Prakash, f_K(M)=C (M/M_sun)^1/2 (R/10km)^-3/2, where M is the (gravitational) mass of Keplerian configuration, R is the (circumferential) radius of

  26. Paulo E. G. Assis, Andreas Fring

    We investigate whether the recently proposed PT-symmetric extensions of generalized Korteweg-de Vries equations admit genuine soliton solutions besides compacton solitary waves. For models which admit stable compactons having a width which is independent of their amplitude and those which possess unstable compacton solutions the Painleve test fails, such tha

  27. Yan Wang, Yajun Mei

    This article is concerned with decentralized sequential testing of a normal mean $μ$ with two-sided alternatives. It is assumed that in a single-sensor network system with limited local memory, i.i.d. normal raw observations are observed at the local sensor, and quantized into binary messages that are sent to the fusion center, which makes a final decision b

  28. Josip Trampetic

    In this talk we discuss enveloping algebra based noncommutative gauge field theory, constructed at the first order in noncommutative parameter theta, as an effective, anomaly free theory, with one-loop renormalizable gauge sector. Limits on the scale of noncommutativity parameter Lambda_NC, via related phenomenology and associated experiments, are analyzed a

  29. T. Verhoelst, N. Van der Zypen, S. Hony, L. Decin

    Context: Red super-giant (RSG) stars exhibit significant mass loss through a slow and dense wind. They are often considered to be the more massive counter parts of Asymptotic Giant Branch (AGB) stars. While the AGB mass loss is linked to their strong pulsations, the RSG are often only weakly variable. Aim: To study the conditions at the base of the wind, by

  30. Peter Berg, Justin Findlay

    A bottleneck simulation of road traffic on a loop, using the deterministic cellular automata (CA) Nagel-Schreckenberg model with zero dawdling probability, reveals three types of stationary wave solutions. They consist of i) two shock waves, one at each bottleneck boundary, ii) one shock wave at the boundary and one on the "open" road, and iii) the t

  31. David Issadore, Katherine J. Humphry, Keith A. Brown, Lori Sandberg

    We present a technique to locally and rapidly heat water drops in microfluidic devices with microwave dielectric heating. Water absorbs microwave power more efficiently than polymers, glass, and oils due to its permanent molecular dipole moment that has a large dielectric loss at GHz frequencies. The relevant heat capacity of the system is a single thermally

  32. Alexandros Alexakis

    Numerical simulations of stratified shear flow instabilities are performed in two dimensions in the Boussinesq limit. The density variation length scale is chosen to be four times smaller than the velocity variation length scale so that Holmboe or Kelvin-Helmholtz unstable modes are present depending on the choice of the global Richardson number Ri. Three di

  33. Rainer Luetticke, Ridvan Cinar

    We have developed an Internet-based audience response system (called ARSBO). In this way we combine the advantages of common audience response systems using handheld devices and the easy and cheap access to the Internet. Evaluations of audience response systems in the literature have shown their success: encouraging participation of the students as well as i

  34. Jose Antonio Martin H

    A theory about the implication structure in graph coloring is presented. Discovering hidden relations is a crucial activity in every scientific discipline. The development of mathematical models to study and discover such hidden relations is of the most highest interest. The main contribution presented in this work is a model of hidden relations materialized

  35. I. Zasada, B. Busiakiewicz

    The ferromagnetic nano-structures are recently of great interest for modern investigations. A comparison of the experimental data and theoretical results shows that the use of the standard molecular field approximation is insufficient for the description of nano-structure properties. Therefore, we use the effective field approach in order to show the usefuln

  36. W. Florkowski, W. Broniowski, M. Chojnacki, A. Kisiel

    We show that a consistent hydrodynamic description of soft-hadronic one- and two-particle observables (the HBT radii) studied in the relativistic heavy-ion collisions at RHIC may be obtained if one uses the Gaussian energy density profile as the initial condition. The transverse-momentum spectra, the elliptic flow coefficient $v_2$, and the pionic azimuthall

  37. M. Weigt, R. A. White, H. Szurmant, J. A. Hoch

    Understanding the molecular determinants of specificity in protein-protein interaction is an outstanding challenge of postgenome biology. The availability of large protein databases generated from sequences of hundreds of bacterial genomes enables various statistical approaches to this problem. In this context covariance-based methods have been used to ident

  38. Eli Glasner, Mariusz Lemanczyk, Benjamin Weiss

    We introduce a functor which associates to every measure preserving system (X,B,μ,T) a topological system (C_2(μ),\tilde{T}) defined on the space of 2-fold couplings of μ, called the topological lens of T. We show that often the topological lens "magnifies" the basic measure dynamical properties of T in terms of the corresponding topological properti

  39. M. Mucha-Kruczynski, E. McCann, V. I. Fal'ko

    We present a self-consistent calculation of the interlayer asymmetry in bilayer graphene caused by an applied electric field in magnetic fields. We show how this asymmetry influences the Landau level spectrum in bilayer graphene and the observable inter-Landau level transitions when they are studied as a function of high magnetic field at fixed filling facto

  40. Eric Z. Chen

    A code is said to be two-weight if the non-zero codewords have only two different a weight w1 and w2. Two-weight codes are closely related to strongly regular graphs. In this paper. It is shown that a consta-cyclic code of composite length can be put in the quasi-twisted form. Based on this transformation, a new construction method of quasi-twisted (QT) two-

  41. Carolina Mateo-Segura, Constantin Simovski, George Goussetis, Sergei Tretyakov

    A structure comprising a coupled pair of two-dimensional arrays of oblate plasmonic nanoellipsoids in a dielectric host medium is proposed as a superlens in the optical domain for both horizontal and vertical polarizations. By means of simulations it is demonstrated that a structure formed by silver nanoellipsoids is capable of restoring subwavelength featur

  42. Elena Litvinova, Hans Feldmeier, Jacek Dobaczewski, Victor Flambaum

    The electromagnetic transition between the almost degenerate 5/2+ and 3/2+ states in Th229 is deemed to be very sensitive to potential changes in the fine structure constant alpha. State of the art Hartree-Fock and Hartree-Fock-Bogoliubov calculations are performed to compute the difference in Coulomb energies of the two states which determines the amplifica

  43. Valeria Pettorino, David F. Mota, Georg Robbers, Christof Wetterich

    We show that growing neutrino models, in which the growing neutrino mass stops the dynamical evolution of a dark energy scalar field, lead to a substantial neutrino clustering on the scales of superclusters. Nonlinear neutrino lumps form at redshift z ~ 1 and could partially drag the clustering of dark matter. If observed, large scale non-linear structures c

  44. M. Cignoni, E. Sabbi, A. Nota, M. Tosi

    Deep HST/ACS photometry of the young cluster NGC 602, located in the remote low density "wing" of the Small Magellanic Cloud, reveals numerous pre-main sequence stars as well as young stars on the main sequence. The resolved stellar content thus provides a basis for studying the star formation history into recent times and constraining several stella

  45. Adam Korany, Gadadhar Misra

    A complete list of homogeneous operators in the Cowen-Douglas class $B_n(D)$ is given. This classification is obtained from an explicit realization of all the homogeneous Hermitian holomorphic vector bundles on the unit disc under the action of the universal covering group of the bi-holomorphic automorphism group of the unit disc.

  46. Sandy S. C. Law

    Neutrino properties can play a crucial role in determining the matter-antimatter asymmetry of the universe if thermal leptogenesis is the correct solution to the baryogenesis problem. Owing to this, the study of neutrino models goes beyond the mere purpose of generating tiny neutrino masses, and it is natural to incorporate the puzzle of the cosmic baryon as

  47. Jordi Duarte, Marcos Fernandez, Javier Gonzalez, Richard Jaramillo

    We summarize the R&D activities on a novel semitransparent microstrip sensor to be used on laser-based alignment systems for silicon trackers. The new sensor is used both for particle tracking and laser detection. The aim of this research line is to increase the optical transmittance (T) of Silicon microstrips detectors to infrared light, introducing minor m

  48. Leslie De Koninck

    This paper investigates the relationship between the Logical Algorithms language (LA) of Ganzinger and McAllester and Constraint Handling Rules (CHR). We present a translation schema from LA to CHR-rp: CHR with rule priorities, and show that the meta-complexity theorem for LA can be applied to a subset of CHR-rp via inverse translation. Inspired by the high-

  49. Jean-Marie Hameury, Maxime Viallet, Jean-Pierre Lasota

    Accretion disks in AGN should be subject to the same type of instability as in cataclysmic variables (CVs) or in low-mass X-ray binaries (LMXBs), which leads to dwarf nova and soft X-ray transient outbursts. It has been suggested that this thermal/viscous instability can account for the long term variability of AGNs. We test this assertion by presenting a sy

  50. J. P. Stott, K. A. Pimbblet, A. C. Edge, G. P. Smith

    We investigate the evolution of the optical and near-infrared colour-magnitude relation in an homogeneous sample of massive clusters from z = 1 to the present epoch. By comparing deep Hubble Space Telescope ACS imaging of X-ray selected MACS survey clusters at z = 0.5 to the similarly selected LARCS sample at z = 0.1 we find that the rest-frame d(U -V)/dV sl

  51. Richard Kowar

    In this paper we show that the standard causality condition for attenuated waves, i.e. the Kramers-Kronig relation that relates the attenuation law and the phase speed of the wave, is necessary but not sufficient for causality of a wave. By causality of a wave we understand the property that its wave front speed is bounded. Although this condition is not new

  52. D. Horan, V. A. Acciari, S. M. Bradbury, J. H. Buckley

    Since September 2005, the Whipple 10m Gamma-ray Telescope has been operated primarily as a blazar monitor. The five Northern Hemisphere blazars that have already been detected at the Whipple Observatory, Markarian 421, H1426+428, Markarian 501, 1ES 1959+650 and 1ES 2344+514, are monitored routinely each night that they are visible. We report on the Markarian

  53. The BABAR Collaboration, B. Aubert

    We present measurements of the branching fraction and fraction of longitudinal polarization for the decay B+ -> K*0bar K*+ with a sample of 467 +/- 5 million BBbar pairs collected with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator Laboratory. We obtain the branching fraction Br(B+ -> K*0bar K*+) = (1.2 +/-

  54. Mihail A. Silaev, Takehito Yokoyama, Jacob Linder, Yukio Tanaka

    We consider different effects that arise when time-reversal symmetry breaking superconductors are subjected to an external magnetic field, thus rendering the superconductor to be in the mixed state. We focus in particular on two time-reversal symmetry breaking order parameters which are believed to be realized in actual materials: $p+ıp'$-wave and $d+ıs$

  55. K. V. Sokolovsky, Y. Y. Kovalev

    We investigate the sample of 213 GPS sources selected from simultaneous multi-frequency 1-22 GHz observations obtained with RATAN-600 radio telescope. We use publicly available data to characterize parsec-scale structure of the selected sources. Among them we found 121 core dominated sources, 76 Compact Symmetric Object (CSO) candidates (24 of them are highl

  56. M. Barucci, M. Bassan, B. Buonomo, G. Cavallari

    Peak amplitude measurements of the fundamental mode of oscillation of a suspended aluminum alloy bar hit by an electron beam show that the amplitude is enhanced by a factor ~3.5 when the material is in the superconducting state. This result is consistent with the cosmic ray observations made by the resonant gravitational wave detector NAUTILUS, made of the s

  57. Jordi Miralda-Escude

    Gaztanaga et al. have recently claimed to measure the Baryon Acoustic Oscillation (BAO) scale in the radial direction from the publicly available SDSS DR6 data. They focus on the correlation function of Luminous Red Galaxies (LRG) close to the line-of-sight direction to find a feature that they identify as the BAO peak, arguing that a magnification bias effe

  58. Louis Paulot, Xavier Lacroze

    Constant Proportion Portfolio Insurance (CPPI) is a strategy designed to give participation in a risky asset while protecting the invested capital. Some gap risk due to extreme events is often kept by the issuer of the product: a put option on the CPPI strategy is included in the product. In this paper we present a new method for the pricing of CPPIs and opt

  59. Ludovic Petitdemange, Emmanuel Dormy, Steven A. Balbus

    We show that a simple, modified version of the Magnetorotational Instability (MRI) can develop in the outer liquid core of the Earth, in the presence of a background shear. It requires either thermal wind, or a primary instability, such as convection, to drive a weak differential rotation within the core. The force balance in the Earth's core is very unl

  60. Luc Arnold, François-Marie Bréon, Simon Brewer

    The so-called Vegetation Red-Edge (VRE), a sharp increase in the reflectance around $700 nm$, is a characteristic of vegetation spectra, and can therefore be used as a biomarker if it can be detected in an unresolved extrasolar Earth-like planet integrated reflectance spectrum. Here we investigate the potential for detection of vegetation spectra during the

  61. Luigi Spinoglio, Silvia Tommasin, Matthew A. Malkan

    Infrared photometry and later infrared spectroscopy provided powerful diagnostics to distinguish between the main emission mechanisms in galaxies: AGN and Starburst. After the pioneering work on infrared photometry with IRAS in the far-IR and the S.Pedro Martir and ESO ground-based work in the near-IR, ISO photometry extended up to 200um the coverage of the

  62. A. Miranda

    Approximation methods for calculating individual particle/ field motions in spacetime at the quantum level of accuracy (a key feature of the Bohm Picture of Quantum Mechanics (BP)), are studied. Modern textbook presentations of Quantum Theory are used throughout, but only to provide the necessary, already existing, tested formalisms and calculational techniq

  63. Damiano Fulghesu

    In this paper we explicit the rational Chow ring of the stack consisting of nodal curves of genus 0 with at most 3 nodes: it is a Q-algebra with 10 generators and 11 relations.

  64. Hara Charalambous, Apostolos Thoma

    Let $k$ be a field, $ \mathcal{L}\subset \mathbb{Z}^n$ be a lattice such that $Ł\cap \mathbb{N}^n=\{{\bf 0}\}$, and $I_Ł\subset \Bbbk[x_1,..., x_n]$ the corresponding lattice ideal. We present the generalized Scarf complex of $I_Ł$ and show that it is indispensable in the sense that it is contained in every minimal free resolution of $R/I_Ł$.

  65. A. Schurer, F. Calura, L. Silva, A. Pipino

    We present photometric evolution models of galaxies, in which, in addition to the stellar component, the effects of an evolving dusty interstellar medium have been included with particular care. Starting from the work of Calura, Pipino & Matteucci (2008), in which chemical evolution models have been used to study the evolution of both the gas and dust compon

  66. Damiano Fulghesu

    This is the second in a series of three papers in which we investigate the rational Chow ring of the stack consisting of nodal curves of genus. Here we define the basic classes: the classes of strata and the Mumford classes.

  67. E. Khomenko, O. Kochukhov

    We report 2D time-dependent non-linear magneto-hydrodynamical simulations of waves in the atmospheres of roAp stars. We explore a grid of simulations in a wide parameter space. The aim of our study is to understand the influence of the atmosphere and the magnetic field on the propagation and reflection properties of magneto-acoustic waves, formation of shock

  68. David C Dunbar

    This article brings together in a single place the different components of the six gluon one-loop amplitude

  69. Damiano Fulghesu

    In this series of three papers we start to investigate the rational Chow ring of the stack consisting of nodal curves of genus 0, in particular we determine completely the rational Chow ring of the substack consisting of curves with at most 3 nodes. In this first paper we construct the stack of rational nodal curves and its stratification by nodes and show t

  70. Lev Sakhnovich

    In this paper we use the matrix analogue of eigenvalue $ρ_{min}^{2}$ to formulate and to solve the extremal Nehary problem. When $ρ_{min}$ is a scalar, our approach coincides with Adamjan-Arov-Krein approach.

  71. Thierry Gallay, Violaine Roussier-Michon

    The Navier-Stokes-Coriolis system is a simple model for rotating fluids, which allows to study the influence of the Coriolis force on the dynamics of three-dimensional flows. In this paper, we consider the NSC system in an infinite three-dimensional layer delimited by two horizontal planes, with periodic boundary conditions in the vertical direction. If the

  72. Oleg Lychkovskiy

    The plane-wave approximation is widely used in the practical calculations concerning neutrino oscillations. A simple derivation of this approximation starting from the neutrino wave-packet framework is presented.

  73. Giulia Ventimiglia, Magda Arnaboldi, Ortwin Gerhard

    Using the Multislit Imaging Spectroscopy (MSIS) technique at the FORS2 spectrograph on VLT-UT1, we have identified 60 Intracluster Planetary Nebula (ICPN) candidates associated with the Intracluster Light (ICL) in the central region of the Hydra I cluster. Hydra I is a medium compact, relatively near (~50 Mpc), rich cluster in the southern hemisphere. Here w

  74. Hara Charalambous, Apostolos Thoma

    Let $A$ be a semigroup whose only invertible element is 0. For an $A$-homogeneous ideal we discuss the notions of simple $i$-syzygies and simple minimal free resolutions of $R/I$. When $I$ is a lattice ideal, the simple 0-syzygies of $R/I$ are the binomials in $I$. We show that for an appropriate choice of bases every $A$-homogeneous minimal free resolution

  75. Vincenzo Marotta, Adele Naddeo

    The Morita equivalence for field theories on noncommutative two-tori is analysed in detail for rational values of the noncommutativity parameter theta (in appropriate units): an isomorphism is established between an abelian noncommutative field theory (NCFT) and a non-abelian theory of twisted fields on ordinary space. We focus on a particular conformal fiel

  76. Xavier Sauvage, Abdelahad Chbihi, Dmitry Gunderov, E. V. Belozerov

    The decomposition process mechanisms have been investigated in a Fe50Au25Pd25 (at.%) alloy processed by severe plastic deformation. Phases were characterized by X-ray diffraction and microstructures were observed using transmission electron microscopy. In the coarse grain alloy homogenized and aged at $450 ^{circ}\mathrm{C}$, the bcc α-Fe and fcc AuPd phases

  77. Arnaud Debussche, Erwan Faou

    We consider the linear Schrödinger equation and its discretization by split-step methods where the part corresponding to the Laplace operator is approximated by the midpoint rule. We show that the numerical solution coincides with the exact solution of a modified partial differential equation at each time step. This shows the existence of a modified energy p

  78. Katsuyoshi Matsushita, Jun Sato, Hiroshi Imamura

    In the recent years, a spin-valve was developed with a current-confined-path structure consisting of a non-oxide-layer (NOL). We analyze magnetic structures of the current-confinedpath in the nano-oxide layer sandwiched between ferromagnetic electrodes and clarify the dependency of the magnetic structure on the shape and size of the current-confined-path. Ou

  79. Y. Y. Kovalev

    The high redshift GPS quasar PKS 0858-279 exhibits the following properties which make the source unusual. Our RATAN-600 monitoring of 1-22 GHz spectrum has detected broad-band radio variability with high amplitude and relatively short time scale. In the same time, the milliarcsecond scale structure observed in a snapshot VLBA survey turned out to be very re

  80. Bochao Liu, Markus Buescher, Feng-Kun Guo, Christoph Hanhart

    We investigate the interplay between crossed channel final state interactions and the constraints from two--particle unitarity for the reactions J/psi->V pi pi and VK\bar K, where V is either omega or phi. Using a model where the parameters are largely constrained by other sources, we find that, although small, crossed channel final state interaction can inf

  81. Jianghua Wu, Xu Zhou, Jun Ma, Zhenyu Wu

    The source J 1128+5925 was found recently to show strong intraday variability at radio wavelengths and its radio variability may come from interstellar scintillation. In optical, the object was quiet in our 2007 monitoring session. Here we report the results of our new optical monitoring of this source in 2008. In addition to confirm our 2007 results, that t

  82. A. M. Lunde, A. De Martino, A. Schulz, R. Egger

    We consider electron-electron interaction effects in quantum point contacts on the first quantization plateau, taking into account all scattering processes. We compute the low-temperature linear and nonlinear conductance, shot noise, and thermopower, by perturbation theory and a self-consistent nonperturbative method. On the conductance plateau, the low-temp

  83. S. Ansari, G. Panotopoulos, I. Sachs

    We compute the absorption cross section of space-time scalars on a static D2 rane, in global coordinates, wrapped on the S^2 of an AdS_2 X S^2 X CY_3 geometry. We discuss its relevance for the construction of the dual quantum mechanics of Calabi-Yau black holes.

  84. Mehmet Tekkoyun

    In this study, Lagrangian and Hamiltonian systems, which are mathematical models of mechanical systems, were introduced on the horizontal and the vertical distributions of tangent and cotangent bundles. Finally, some geometrical and physical results related to Lagrangian and Hamiltonian dynamical systems were deduced.

  85. Hakime Seddik, Ralf Greve, Shin Sugiyama, Renji Naruse

    A numerical model was developed for simulating the formation of U-shaped glacial valleys by coupling a two-dimensional ice flow model with an erosion model for a transverse cross section. The erosion model assumes that the erosion rate varies quadratically with sliding speed. We compare the two-dimensional model with a simple shallow-ice approximation model

  86. Ryo Takahashi

    Let R be a commutative noetherian local ring, and let X be a resolving subcategory of the category of finitely generated R-modules. In this paper, we study modules in X by relating them to modules in X which are free on the punctured spectrum of R. We do this by investigating nonfree loci and establishing an analogue of the notion of a level in a triangulate

  87. Hitoshi Nishino, Subhash Rajpoot

    We present two alternative field contents for Bagger-Lambert theory, based on the triality of SO(8). The first content is (φ_{A a}, χ_{\dot A a} ; A_\m{}^{a b}), where the bosonic field φis in the 8_S of SO(8) instead of the 8_V as in the original Bagger-Lambert formulation. The second field content is (φ_{\dot A a}, χ^I{}_a ; A_\m{}^{a b}), where the bosoni

  88. Zhenyuan Zhao, Juan Camilo Bohorquez, Alex Dixon, Neil F. Johnson

    Fights-to-the-death occur in many natural, medical and commercial settings. Standard mass action theory and conventional wisdom imply that the minority (i.e. smaller) group's survival time decreases as its relative initial size decreases, in the absence of replenishment. Here we show that the opposite actually happens, if the minority group features inte

  89. Michael Dine, Guido Festuccia, Alexander Morisse

    Supersymmetric vacua are stable. It is interesting to ask: how long-lived are vacua which are nearly supersymmetric? This question is relevant if our universe is approximately supersymmetric. It is also of importance for a number of issues of the physics of the landscape and eternal inflation. In this note, we distinguish a variety of cases. In all of them t

  90. Z. F. Xu, P. Zhang, C. Raman, L. You

    We study the mechanisms and the limits of pumping vorticity into a spinor condensate through manipulations of magnetic (B-) fields. We discover a fundamental connection between the geometrical properties of the magnetic fields and the quantized circulation of magnetically trapped atoms, a result which generalizes several recent experimental and theoretical s

  91. Ming-Deh Huang, Anand Kumar Narayanan

    We describe a new class of list decodable codes based on Galois extensions of function fields and present a list decoding algorithm. These codes are obtained as a result of folding the set of rational places of a function field using certain elements (automorphisms) from the Galois group of the extension. This work is an extension of Folded Reed Solomon code

  92. Elsa Couderc, Spencer Klein

    The momentum transfer $Δk$ required for a photon to scatter from a target and emerge as a $ρ^0$ decreases as the photon energy $k$ rises. For $k>3\times10^{14}$ eV, $Δk$ is small enough that the interaction cannot be localized to a single nucleus. At still higher energies, photons may coherently scatter elastically from bulk matter and emerge as a $ρ^0$, in

  93. N. M. McClure-Griffiths, D. J. Pisano, M. R. Calabretta, H. A. Ford

    The Parkes Galactic All-Sky Survey (GASS) is a survey of Galactic atomic hydrogen (HI) emission in the Southern sky covering declinations $δ\leq 1^{\circ}$ using the Parkes Radio Telescope. The survey covers $2π$ steradians with an effective angular resolution of ~16', at a velocity resolution of 1.0 km/s, and with an rms brightness temperature noise of

  94. Michael S. Kirk, W. Dean Pesnell, C. Alex Young, Shea A. Hess Webber

    A new method for automated detection of polar coronal holes is presented. This method, called perimeter tracing, uses a series of 171, 195, and 304 Å full disk images from the Extreme ultraviolet Imaging Telescope (EIT) on SOHO over solar cycle 23 to measure the perimeter of polar coronal holes as they appear on the limbs. Perimeter tracing minimizes line-of

  95. P. Exner, M. Fraas

    We study singular Schrodinger operators with an attractive interaction supported by a closed smooth surface A in R^3 and analyze their behavior in the vicinity of the critical situation where such an operator has empty discrete spectrum and a threshold resonance. In particular, we show that if A is a sphere and the critical coupling is constant over it, any

  96. Karl Schwede

    In this paper we study singularities defined by the action of Frobenius in characteristic $p > 0$. We prove results analogous to inversion of adjunction along a center of log canonicity. For example, we show that if $X$ is a Gorenstein normal variety then to every normal center of sharp $F$-purity $W \subseteq X$ such that $X$ is $F$-pure at the generic poin

  97. Hideki Maeda, Tomohiro Harada, B. J. Carr

    Motivated by the cosmological wormhole solutions obtained from our recent numerical investigations, we provide a definition of a wormhole which applies to dynamical situations. Our numerical solutions do not have timelike trapping horizons but they are wormholes in the sense that they connect two or more asymptotic regions. Although the null energy condition

  98. K. Lodders, H. Palme, H. -P. Gail

    A review of the abundances and condensation temperatures of the elements and their nuclides in the solar nebula and in chondritic meteorites. Abundances of the elements in some neighboring stars are also discussed.

  99. Arturo Berrones

    A novel formalism for Bayesian learning in the context of complex inference models is proposed. The method is based on the use of the Stationary Fokker--Planck (SFP) approach to sample from the posterior density. Stationary Fokker--Planck sampling generalizes the Gibbs sampler algorithm for arbitrary and unknown conditional densities. By the SFP procedure ap

  100. Fabio Fontanot, Gabriella De Lucia, Pierluigi Monaco, Rachel S. Somerville

    [abridged] It has been widely claimed that several lines of observational evidence point towards a "downsizing" (DS) of the process of galaxy formation over cosmic time. This behavior is sometimes termed "anti-hierarchical", and contrasted with the "bottom-up" assembly of the dark matter structures in Cold Dark Matter models. In this