September 2007 arXiv papers — page 19
Showing 1,801–1,900 of 4,824 papers
Solange V. Ramirez, Richard G. Arendt, Kris Sellgren, Susan R. Stolovy
We have obtained Spitzer/IRAC observations of the central 2.0 x 1.4 degrees (~280 x 200 pc) of the Galaxy at 3.6-8.0 microns. A point source catalog of 1,065,565 objects is presented. The catalog includes magnitudes for the point sources at 3.6, 4.5, 5.8, and 8.0 microns, as well as JHK photometry from 2MASS. The point source catalog is confusion limited wit
Decio Levi, Sébastien Tremblay, Pavel Winternitz
A method is presented for finding the Lie point symmetry transformations acting simultaneously on difference equations and lattices, while leaving the solution set of the corresponding difference scheme invariant. The method is applied to several examples. The found symmetry groups are used to obtain particular solutions of differential-difference equations.
Djordje Sijacki
The group of the p-brane world volume preserving diffeomorphism is considered. The infinite-dimensional spinors of this group are related, by the nonlinear realization techniques, to the corresponding spinors of its linear subgroup, that are constructed explicitly. An algebraic construction of the Virasoro and Neveu-Schwarz-Ramond algebras, based on this inf
Alfred Ramani, Basile Grammaticos, Sébastien Tremblay
We examine whether the Painlevé property is a necessary condition for the integrability of nonlinear ordinary differential equations. We show that for a large class of linearisable systems this is not the case. In the discrete domain, we investigate whether the singularity confinement property is satisfied for the discrete analogues of the non-Painlevé conti
Jan Ambjorn, Jens Anders Gesser
We show how non-compact space-time (ZZ branes) emerges as a limit of compact space-time (FZZT branes) for specific ratios between the square of the boundary cosmological constant and the bulk cosmological constant in the (2,2m - 1) minimal model coupled to two-dimensional euclidean quantum gravity. Furthermore, we show that the principal (r,s) ZZ brane can b
Ayoub Nassour, Joseph Hugel, A. V. Postnikov
A simple and accurate method of calculating phonon spectra in mixed semiconductors alloys, on the basis of preliminarily (from first principles) relaxed atomic structure, is proposed and tested for (Zn,Be)Se and (Ga,In)As solid solutions. The method uses an observation that the interatomic force constants, calculated ab initio for a number of microscopic con
Stephen E. Zepf, Thomas J. Maccarone, Gilles Bergond, Arunav Kundu
We present the discovery of [OIII] 5007 emission associated with the black hole X-ray binary recently identified in a globular cluster in the Virgo elliptical galaxy NGC 4472. This object is the first confirmed black-hole X-ray binary in a globular cluster. The identification of [OIII] 5007 emission from the black-hole hosting globular cluster is based on tw
Edward W. Kolb
In these two lectures I will discuss some outstanding problems in the standard model of cosmology, concentrating on the physics that might be related to the title of this school, ``Searching for the totally unexpected in the LHC era.'' In particular, I will concentrate on dark energy, dark matter, and inflation.
D. Malmberg, M. B. Davies, J. E. Chambers, F. De Angeli
Most stars are formed in a cluster or association, where the number density of stars can be high. This means that a large fraction of initially-single stars will undergo close encounters with other stars and/or exchange into binaries. We describe how such close encounters and exchange encounters can affect the properties of a planetary system around a single
Emil Rupp, Albert Einstein and the canal ray experiments on wave-particle duality: Scientific fraud and theoretical bias
physics.hist-phJeroen van Dongen
In 1926 Emil Rupp published a number of papers on the interference properties of light emitted by canal ray sources. These articles, particularly one paper that came into being in collaboration with Albert Einstein, drew quite some attention as they probed the wave versus particle nature of light. They also significantly propelled Rupp's career, even tho
Sébastien Tremblay, Basile Grammaticos, Alfred Ramani
In this paper we investigate the integrability of two-dimensional partial difference equations using the newly developed techniques of study of the degree of the iterates. We show that while for generic, nonintegrable equations, the degree grows exponentially fast, for integrable lattice equations the degree growth is polynomial. The growth criterion is used
Vinay L. Kashyap, Jennifer Posson-Brown
We analyze 205 ks of imaging data of the active binary, Capella, obtained with the Chandra High Resolution Camera Imager (HRC-I) to determine whether Capella shows any variability at timescales < 50 ks. We find that a clear signal for variability is present for timescales < 20 ks, and that the light curves show evidence for excess fluctuation over that expec
D. J. Saunders, M. Crampin
We construct, for a homogeneous Lagrangian of arbitrary order in two independent variables, a differential 2-form with the property that it is closed precisely when the Lagrangian is null. This is similar to the property of the `fundamental Lepage equivalent' associated with first-order Lagrangians defined on jets of sections of a fibred manifold.
Letizia Stanghellini
The correlations between planetary nebula (PN) morphology and the nature of their progenitors are explored by examining homogeneous PN samples in the Galaxy and the Magellanic Clouds. We selected PNe with reliable abundances from spectral analysis, and whose morphology is known, and compared the abundances of the element at variance with stellar evolution wi
A. G. Gibb, C. J. Davis, T. J. T. Moore
Results are presented of a survey of SiO 5-4 emission observed with the James Clerk Maxwell Telescope (JCMT) towards a sample of outflows from massive young stellar objects. The sample is drawn from a single-distance study by Ridge & Moore. In a sample of 12 sources, the 5-4 line was detected in 5, a detection rate of 42 per cent. This detection rate is high
Mike J. Cai, Hsien Shang, Hsiao-Hsuan Lin, Frank H. Shu
The interaction of accretion disks with the magnetospheres of young stars can produce X-winds and funnel flows. With the assumption of axial symmetry and steady state flow, the problem can be formulated in terms of quantities that are conserved along streamlines, such as the Bernoulli integral (BI), plus a partial differential equation (PDE), called the Grad
David G. Turner, Ivan S. Bryukhanov, Igor I. Balyuk, Alexey M. Gain
Observations of the light curve for the 3.7-day Cepheid RT Aur both before and since 1980 indicate that the variable is undergoing an overall period increase, amounting to +0.082 +-0.012 s/yr, rather than a period decrease, as implied by all observations prior to 1980. Superposed on the star's O-C variations is a sinusoidal trend that cannot be attribute
Josephson dynamics for coupled polariton modes under the atom-field interaction in the cavity
quant-phA. P. Alodjants, S. M. Arakelian, S. N. Bagayev, V. S. Egorov
We consider a new approach to the problem of Bose-Einstein condensation (BEC) of polaritons for atom-field interaction under the strong coupling regime in the cavity. We investigate the dynamics of two macroscopically populated polariton modes corresponding to the upper and lower branch energy states coupled via Kerr-like nonlinearity of atomic medium. We fo
Frank Goldenbaum
This contribution essentially will be divided into two parts: First, a brief overview on topical accelerator applications in Europe, a selection of the European 6th framework accelerator and ADS programs will be given, second the emphasis will be put on selected nuclear data required for designing facilities planned or even under construction. In this second
Richard F. Bass, Huili Tang
Let $α\in (0,2)$ and consider the operator $$L f(x) =\int [f(x+h)-f(x)-1_{(|h|\leq 1)} \nabla f(x)\cdot h] \frac{A(x,h)}{|h|^{d+α}} dh, $$ where the $\nabla f(x)\cdot h$ term is omitted if $α<1$. We consider the martingale problem corresponding to the operator $L$ and under mild conditions on the function $A$ prove that there exists a unique solution.
Thorsten Naab, Andreas Burkert, Peter H. Johansson, Roland Jesseit
Galactic spheroids can form as a result of galaxy interactions and mergers of disks. Detailed analyses of the photometric properties, the intrinsic orbital structure, the line-of-sight velocity distributions and the kinemetry of simulated merger remnants, which depend critically on the geometry and the gas content of the interacting progenitors, indicate tha
E. T. Tomboulis, A. Velytsky
We study decimation procedures and effective (improved) actions in the framework of Monte Carlo Renormalization Group (MCRG). Particular attention is paid to matching the form of the effective action to the decimation procedure parameters. Using the static quark-antiquark potential in SU(2) LGT we probe different distance scales and find that an effective ac
Spitzer/IRS Observations of Seyfert 1.8s and 1.9s: A Comparison with Seyfert 1s and Seyfert 2s
astro-phR. P. Deo, D. M. Crenshaw, S. B. Kraemer, M. Dietrich
We present Spitzer Space Telescope mid-infrared spectra of 12 Seyfert 1.8 and 1.9 galaxies over the 5-38 um region. We compare the spectral characteristics of this sample to those of 58 Seyfert 1 and Seyfert 2 galaxies from the Spitzer archives. An analysis of the spectral shapes, the silicate 10 um feature and the emission line fluxes have enabled us to cha
S. Y. Li, J. -B. Bonnemaison, A. Payeur, P. Fournier
The effect of sample size and surface roughness on the phonon thermal conductivity $κ_p$ of Nd$_2$CuO$_4$ single crystals was studied down to 50 mK. At 0.5 K, $κ_p$ is proportional to $\sqrt{A}$, where $A$ is the cross-sectional area of the sample. This demonstrates that $κ_p$ is dominated by boundary scattering below 0.5 K or so. However, the expected $T^3$
F. Finelli, P. Peter, N. Pinto-Neto
We introduce analytic solutions for a class of two components bouncing models, where the bounce is triggered by a negative energy density perfect fluid. The equation of state of the two components are constant in time, but otherwise unrelated. By numerically integrating regular equations for scalar cosmological perturbations, we find that the (would be) grow
Intermittency and Universality in Fully-Developed Inviscid and Weakly-Compressible Turbulent Flows
nlin.CDRoberto Benzi, Luca Biferale, Robert Fisher, Leo Kadanoff
We performed high resolution numerical simulations of homogenous and isotropic compressible turbulence, with an average 3D Mach number close to 0.3. We study the statistical properties of intermittency for velocity, density and entropy. For the velocity field, which is the primary quantity that can be compared to the isotropic incompressible case, we find no
The Distance of the First Overtone RR Lyrae Variables in the MACHO LMC Database: A New Method to Correct for the Effects of Crowding
astro-phC. M. Clement, X. Xu, A. V. Muzzin
Previous studies have indicated that many of the RR Lyrae variables in the LMC have properties similar to the ones in the Galactic globular cluster M3. Assuming that the M3 RR Lyrae variables follow the same relationships among period, temperature, amplitude and Fourier phase parameter phi31 as their LMC counterparts, we have used the M3 phi31-logP relation
Anindya Das, A. K. Sood, Prabal K. Maiti, Mili Das
We have calculated the binding energy of various nucleobases (guanine (G), adenine (A), thymine (T) and cytosine (C)) with (5,5) single-walled carbon nanotubes (SWNTs) using ab-initio Hartre-Fock method (HF) together with force field calculations. The gas phase binding energies follow the sequence G $>$ A $>$ T $>$ C. We show that main contribution to bindin
Guillaume Laibe, Jean-François Gonzalez, Laure Fouchet, Sarah T. Maddison
We present the first results of the treatment of grain growth in our 3D, two-fluid (gas+dust) SPH code describing protoplanetary disks. We implement a scheme able to reproduce the variation of grain sizes caused by a variety of physical processes and test it with the analytical expression of grain growth given by Stepinski & Valageas (1997) in simulations of
Brane Solutions in Time Dependent Backgrounds in D = 11 Supergravity and in Type II String Theories
hep-thSrikumar Sen Gupta
We obtain explicit time dependent brane solutions in M-theory as well as in string theory by solving the reduced equations of motion (which follow from 11-d supergravity) for a class of brane solutions in curved backgrounds. The behaviour of our solutions in both asymptotic and near-horizon limits are studied. It is shown that our time dependent solutions se
Takeshi Fukuhara, Seiji Sugawa, Yoshiro Takahashi
We report the observation of a Bose Einstein condensate in a bosonic isotope of ytterbium (170Yb). More than 10^6 atoms are trapped in a crossed optical dipole trap and cooled by evaporation. Condensates of approximately 10^4 atoms have been obtained. From an expansion of the condensate, we have extracted the scattering length a=3.6(9) nm.
Relation between full traces of Green functions for initial and Darboux transformed Dirac problems
hep-thEkaterina Pozdeeva
We establish the relation between full traces of the Green functions for some initial and the Darboux transformed one-dimensional two component Dirac problems with the most general form of potential. The result is used to check the completeness of set of wave functions obtained by the Darboux transformation of the eigenfunctions set for the initial Dirac pro
C. Pagliarone, A. Fernandez-Tellez
The use of large underground high-energy physics experiments, for comic ray studies, have been used, in the past, at CERN, in order to measure, precisely, the inclusive cosmic ray flux in the energy range from 2x10^10 - 2x10^12 eV. ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and, together with other ALICE apparatus, will provid
VLT / Infrared Integral Field Spectrometer Observations of Molecular Hydrogen Lines in the Knots in the Planetary Nebula NGC 7293 (the Helix Nebula)
astro-phM. Matsuura, A. K. Speck, M. D. Smith, A. A. Zijlstra
Knots are commonly found in nearby planetary nebulae (PNe) and star forming regions. Within PNe, knots are often found to be associated with the brightest parts of the nebulae and understanding the physics involved in knots may reveal the processes dominating in PNe. As one of the closest PNe, the Helix Nebula (NGC 7293) is an ideal target to study such smal
Daniel Valdez-Balderas, David Stroud
We study a model for the pinning of vortices in a two-dimensional, inhomogeneous, Type-II superconductor in its mixed state. The model is based on a Ginzburg-Landau (GL) free energy functional whose coefficients are determined by the mean-field transition temperature T_{c0} and the zero-temperature penetration depth λ(0). We find that if (i) T_{c0} and λ(0)
Monte Carlo study of the evaporation/condensation transition on different Ising lattices
cond-mat.stat-mechAndreas Nußbaumer, Elmar Bittner, Wolfhard Janke
In 2002 Biskup et al. [Europhys. Lett. 60, 21 (2002)] sketched a rigorous proof for the behavior of the 2D Ising lattice gas, at a finite volume and a fixed excess δM of particles (spins) above the ambient gas density (spontaneous magnetisation). By identifying a dimensionless parameter Δ(δM) and a universal constant Δ_c, they showed in the limit of large sy
Heavily obscured AGN with BeppoSAX, INTEGRAL, SWIFT, XMM and Chandra: prospects for Simbol-X
astro-phR. Della Ceca, P. Severgnini, A. Caccianiga, A. Comastri
According to the latest versions of synthesis modeling of the Cosmic X-ray Background, Compton Thick AGN should represent ~50% of the total absorbed AGN population. However, despite their importance in the cosmological context, only a few dozens of Compton Thick AGN have been found and studied so far. We will briefly review this topic and discuss the improve
Giant magnetoelectric effect induced by intrinsic surface stress in ferroic nanorods
cond-mat.mtrl-sciM. D. Glinchuk, E. A. Eliseev, A. N. Morozovska, R. Blinc
The general approach for the consideration of the magnetoelectric effects in ferroic nanorods is proposed in the framework of the phenomenological theory. The intrinsic surface stress, magneto- and electrostriction as well as piezoelectric and piezomagnetic effects are included into the free energy. The intrinsic surface stress under the curved nanoparticle
G. Bozzi, B. Fuks, M. Klasen
We present a precision calculation of the transverse-momentum and invariant-mass distributions for supersymmetric particle pair production at hadron colliders, focusing on Drell-Yan like slepton pair and slepton-sneutrino associated production at the CERN Large Hadron Collider. We implement the joint resummation formalism at the next-to-leading logarithmic a
John Friedlander, Florian Luca
We show, in an effective way, that there exists a sequence of congruence classes $a_k\pmod {m_k}$ such that the minimal solution $n=n_k$ of the congruence $ϕ(n)\equiv a_k\pmod {m_k}$ exists and satisfies $\log n_k/\log m_k\to\infty $ as $k\to\infty$. Here, $ϕ(n)$ is the Euler function. This answers a question raised in \cite{FS}. We also show that every cong
B. Béri, J. H. Bardarson, C. W. J. Beenakker
We consider the effect of spin-orbit coupling on the energy levels of a single-channel Josephson junction below the superconducting gap. We investigate quantitatively the level splitting arising from the combined effect of spin-orbit coupling and the time-reversal symmetry breaking by the phase difference between the superconductors. Using the scattering mat
H. B. Coldenstrodt-Ronge, C. Silberhorn
Avalanche photo detection is commonly used in applications which require single photon sensitivity. We examine the limits of using avalanche photo diodes (APD) for characterising photon statistics at high data rates. To identify the regime of linear APD operation we employ a ps-pulsed diode laser with variable repetition rates between 0.5MHz and 80MHz. We mo
Igor Chilingarian
A great effort is being made by the international Virtual Observatory community to build tools ready to be used by scientists. Presently, providing access to theoretical spectra in general, and synthetic spectra of galaxies in particular, is a matter of current interest in the Virtual Observatory. Several ways of accessing such spectra are available. We pres
S. Longhi, G. Della Valle, M. Ornigotti, P. Laporta
We report on the first experimental demonstration of light transfer in an engineered triple-well optical waveguide structure which provides a classic analogue of Coherent Tunnelling by Adiabatic Passage (CTAP) recently proposed for coherent transport in space of neutral atoms or electrons among tunneling-coupled optical traps or quantum wells [A.D. Greentree
David A. Kessler
We study the Susceptible-Infected-Susceptible model of the spread of an endemic infection. We calculate an exact expression for the mean number of transmissions for all values of the population and the infectivity. We derive the large-N asymptotic behavior for the infectivitiy below, above, and in the critical region. We obtain an analytical expression for t
Evgueni Goudzovski
Several recent results from the NA48 experiment are presented: a measurement $|η_{+-}|$, search for CP violating phenomena in $K^\pm\to3π$ decays, and a measurement of $|V_{us}|$.
NBursts: Simultaneous Extraction of Internal Kinematics and Parametrized SFH from Integrated Light Spectra
astro-phIgor Chilingarian, Philippe Prugniel, Olga Sil'chenko, Mina Koleva
We present a novel approach for simultaneous extraction of stellar population parameters and internal kinematics from the spectra integrated along a line of sight. We fit a template spectrum into an observed one in a pixel space using a non-linear $χ^2$ minimization in the multidimensional parameter space, including characteristics of the line-of-sight veloc
Maria Markosova
The phenomenon of human language is widely studied from various points of view. It is interesting not only for social scientists, antropologists or philosophers, but also for those, interesting in the network dynamics. In several recent papers word web, or language as a graph has been investigated. In this paper I revise recent studies of syntactical word we
Christophe Marecaux, Matthieu Chabanas, Yohan Payan, Franck Boutault
This paper suggests a full protocol of Computer Aided Surgery as previously recommended in literature addressing the challenging task of primary or secondary reconstruction of orbito-zygomatic dislocation. First, on a specifically developed planning software, the best zygoma reduction and orbital boundaries reconstruction to achieve skeletal symmetry are det
Hitoshi Murayama
The kind of supersymmetry that can be discovered at the LHC must be very much flavor-blind, which used to require very special intelligently designed models of supersymmetry breaking. This led to the pessimism for some in the community that it is not likely for the LHC to discover supersymmetry. I point out that this is not so, because a garden-variety super
V. Turkowski, C. A. Ullrich
We formulate a time-dependent density functional theory (TDDFT) in terms of the density matrix to study ultrafast phenomena in semiconductor structures. A system of equations for the density matrix components, which is equivalent to the time-dependent Kohn-Sham equation, is derived. From this we obtain a TDDFT version of the semiconductor Bloch equations, wh
Stéphanie Buchaillard, Muriel Brix, Pascal Perrier, Yohan Payan
This paper presents the current achievements of a long term project aiming at predicting and assessing the impact of tongue and mouth floor surgery on tongue mobility. The ultimate objective of this project is the design of a software with which surgeons should be able (1) to design a 3D biomechanical model of the tongue and of the mouth floor that matches t
B. E. Cox, F. K. Loebinger, A. D. Pilkington
A detailed study is presented of the search for Higgs bosons in the b-decay channel in the central exclusive production process at the LHC. We present results for proton tagging detectors at both 220m and 420m around ATLAS or CMS. We consider two benchmark scenarios; a Standard Model (SM) Higgs boson and the m_h^{max} scenario of the Minimal Supersymmetric S
Query Evaluation in P2P Systems of Taxonomy-based Sources: Algorithms, Complexity, and Optimizations
cs.DBCarlo Meghini, Yannis Tzitzikas, Anastasia Analyti
In this study, we address the problem of answering queries over a peer-to-peer system of taxonomy-based sources. A taxonomy states subsumption relationships between negation-free DNF formulas on terms and negation-free conjunctions of terms. To the end of laying the foundations of our study, we first consider the centralized case, deriving the complexity of
Gian Michele Graf, Gregorio Ortelli
We compare the charges transported in two systems, a spatially periodic and an open quantum pump, both depending periodically and adiabatically on time. The charge transported in a cycle was computed by Thouless, respectively by Buttiker et al. in the two cases. We show that the results agree in the limit where the two physical situations become the same, i.
Michael Hermele, T. Senthil, Matthew P. A. Fisher
We correct an error in our paper Phys. Rev. B 72, 104404 (2005) [cond-mat/0502215]. We show that a particular fermion bilinear is not related to the other ``competing orders'' of the algebraic spin liquid, and does not possess their slowly decaying correlations. For the square lattice staggered flux spin liquid (equivalently, d-wave RVB state), this
Recent results on (anti)nucleus and (anti)hyperon production in nucleus-nucleus collisions at CERN SPS energies
nucl-exG. L. Melkumov
The NA49 experiment has collected comprehensive data on particle production in nucleus-nucleus collisions over the whole SPS beam energies range, the critical energy domain where the expected phase transition to a deconfined phase is expected to occur. The latest results from Pb+Pb collisions between 20$A$ GeV and 158$A$ GeV on baryon stopping and light nucl
Petter Andreas Bergh, Karin Erdmann
We construct a minimal projective bimodule resolution for every finite dimensional quantum complete intersection of codimension two. Then we use this resolution to compute both the Hochschild cohomology and homology for such an algebra. In particular, we show that the cohomology vanishes in high degrees, while the homology is always nonzero.
David Amitrano
We propose a mechanical model for the behaviour of rocks based on progressive damage at the elementary scale and elastic interaction. It allows us to simulate several experimental observations: mechanical behaviour ranging from brittle to ductile, fractal structure of the damage, powerlaw distribution of the damage avalanches. These macroscopic properties ar
Simon E. Shaw, Ada Paizis, Nami Mowlavi, Stephane Paltani
The X-ray spectra of Low Mass X-ray Binaries (LMXB) can change on short time-scales, making it difficult to follow their spectral characteristics in detail through model fitting. Colour-colour (C-C) diagrams are therefore often used as alternative, model independent, tools to study the spectral variability of these sources. The INTEGRAL mission, with its hig
S. A. Mikhailov
We study the non-linear electromagnetic response of graphene taking into account the self-consistent-field effects. Response of the system to a strong pulse excitation is calculated. It is shown that radiative decay in graphene differs from that of conventional two-dimensional electron systems both quantitatively and qualitatively. Possible applications of t
L. Bassani, R. Landi, A. Malizia, M. T. Fiocchi
We report on the identification of a new soft gamma ray source, namely IGR J22517+2218, detected with IBIS/INTEGRAL. The source, which has an observed 20-100 keV flux of ~4 x10^-11 erg cm-2 s-1, is spatially coincident with MG3 J225155+2217, a quasar at z=3.668. The Swift/XRT 0.5-10 keV continuum is flat (Gamma=1.5) with evidence for a spectral curvature bel
David Peyrou, Fabienne Pennec, Hikmat Achkar, Patrick Pons
This paper outlines the issues related to RF MEMS packaging and low actuation voltage. An original approach is presented concerning the modeling of capacitive contacts using multiphysics simulation and advanced characterization. A similar approach is used concerning packaging development where multi-physics simulations are used to optimize the process. A dev
Hacene Belbachir, Adrien Boussicault, Jean-Gabriel Luque
We investigate the link between rectangular Jack polynomials and Hankel hyperdeterminants. As an application we give an expression of the even power of the Vandermonde in term of Jack polynomials.
L. Alvarez-Ruso, L. S. Geng, S. Hirenzaki, M. J. Vicente Vacas
We have investigated the neutrino induced coherent pion production reaction at the energies of interest for recent experiments like K2K and MiniBooNE. The model includes pion, nucleon and the Delta(1232) resonance. Medium effects in the production mechanism and the distortion of the pion wave function are taken into account. We find a strong reduction of the
Nature and statistics of majority rankings in a dynamical model of preference aggregation
physics.soc-phG. L. Columbu, A. De Martino, A. Giansanti
We present numerical results on a complex dynamical model for the aggregation of many individual rankings of S alternatives by the pairwise majority rule under a deliberative scenario. Agents are assumed to interact when the Kemeny distance between their rankings is smaller than a range R. The main object of interest is the probability that the aggregate (so
Kevin Schawinski, Daniel Thomas, Marc Sarzi, Claudia Maraston
A major amendment in recent models of hierarchical galaxy formation is the inclusion of so-called AGN feedback. The energy input from an active central massive black hole is invoked to suppress star formation in early-type galaxies at later epochs. A major problem is that this process is poorly understood, and compelling observational evidence for its mere e
Walter Winter
Future neutrino oscillation measurement focus, at first priority, on the discovery of sin^2(2 theta_13) describing the coupling between solar and atmospheric oscillations. In this talk, we briefly discuss the prospects to measure sin^2(2 theta_13) by future reactor and beam experiments, and we illustrate the usefulness of these measurements (and their precis
A. Sacchetti, M. Weller, J. L. Gavilano, R. Mudliar
We report the results of a $^{63,65}$Cu NMR/NQR study probing the intermetallic compound PrCu$_2$. The previously claimed onset of magnetic order at 65 K, indicated in a $μ$SR study, is not confirmed. Based on our data we discuss different possible reasons for this apparent discrepancy, including a non negligible influence of the implanted muons on their env
V. Holzwarth
Fast rotating cool stars are characterised by high magnetic activity levels and frequently show dark spots up to polar latitudes. Their distinctive surface distributions of magnetic flux are investigated in the context of the solar-stellar connection by applying the solar flux eruption and surface flux transport models to stars with different rotation rates,
Jorick S. Vink
I present the results of radiation-driven mass-loss predictions for hot stars of all mass. Mass loss is an important aspect for the evolution of massive stars, the rotational properties of the progenitors of gamma-ray bursts, and is essential in assessing whether the most massive stars explode as pair-instability supernovae, or avoid them due to mass loss. A
V. V. Dmitriev, D. A. Krasnikhin, N. Mulders, D. E. Zmeev
We have found a new stable spin state in the A-like phase of superfluid 3He confined to intrinsically anisotropic aerogel. The state can be formed by radiofrequency excitation applied while cooling through the superfluid transition temperature and its NMR properties are different from the standard A-like phase obtained in the limit of very small excitation.
Eric Larose, Oleg I. Lobkis, Richard L. Weaver
Coherent backscattering is due to constructive interferences of reciprocal paths and leads to an enhancement of the intensity of a multiply scattered field near its source. To observe this enhancement an array of receivers is conventionally placed close to the source. Our approach here is different. In a first experiment, we recover the coherent backscatteri
Makito Oi
Superdeformed states in light $N=Z$ nuclei are studied by means of the self-consistent cranking calculation (i.e., the P + QQ model based on the cranked Hartree-Fock-Bogoliubov method). Analyses are given for two typical cases of superdeformed bands in the $A \simeq 40$ mass region, that is, bands where backbending is absent ($^{40}$Ca) and present ($^{36}$A
N. Mauron, K. S. Gigoyan, T. R. Kendall
The goal of this paper is to present and analyse a new sample of cool carbon (C)stars located in the halo. Twenty three new C stars were discovered. Spectra are typical of N-type stars with C2 and CN bands and sometimes Halpha in emission. ... Four objects are particularly red with J-K > 3, with 2 located at more than 5 kpc. from the Galactic plane. Eight ad
Andriy Yurachkivsky
Let $Q$ denote the space of signed measures on the Borel $σ$-algebra of a separable complete space $X$. We endow $Q$ with the norm $\|q\|=\sup|\intϕdq|$, where the supremum is taken over all Lipschitz with constant 1 functions whose module does not exceed unity. This normed space is incomplete provided $X$ is infinite and has at least one limit point. We cal
Roberto Notari, Eva Riccomagno, Maria-Piera Rogantin
In the context of algebraic statistics an experimental design is described by a set of polynomials called the design ideal. This, in turn, is generated by finite sets of polynomials. Two types of generating sets are mostly used in the literature: Groebner bases and indicator functions. We briefly describe them both, how they are used in the analysis and plan
Burra G. Sidharth
We show that many ancient Indian mythological legends are really allegorical depictions of astronomical and other physical phenomena of which the composers had a good idea. This detail enables us to also use techniques of astronomical chronology for dating various events.
From matrix models' topological expansion to topological string theories: counting surfaces with algebraic geometry
hep-thN. Orantin
The 2-matrix model has been introduced to study Ising model on random surfaces. Since then, the link between matrix models and combinatorics of discrete surfaces has strongly tightened. This manuscript aims to investigate these deep links and extend them beyond the matrix models, following my work's evolution. First, I take care to define properly the he
Yoichi Chizaki, Shigeaki Yahikozawa
We completely accomplish the canonically covariant quantization of Ramond-Neveu-Schwarz (RNS) superstrings in the pp-wave background with a non-zero flux of the NS-NS antisymmetric two-form field. Here this flux is equivalent to a nonvanishing torsion. In this quantization, general operator solutions, which satisfy the entire equation of motion and all the c
Michael Taylor, Angeles I. Diaz
A growing number of indicators are now being used with some confidence to measure the metallicity(Z) of photoionisation regions in planetary nebulae, galactic HII regions(GHIIRs), extra-galactic HII regions(EGHIIRs) and HII galaxies(HIIGs). However, a universal indicator valid also at high metallicities has yet to be found. Here, we report on a new artificia
A. Lecchini-Visintini, J. Lygeros, J. Maciejowski
Simulated annealing is a popular method for approaching the solution of a global optimization problem. Existing results on its performance apply to discrete combinatorial optimization where the optimization variables can assume only a finite set of possible values. We introduce a new general formulation of simulated annealing which allows one to guarantee fi
R. Sattler, J. Eggers, C. Wagner
When a dilute polymer solution experiences capillary thinning, it forms an almost uniformly cylindrical thread, which we study experimentally. In the last stages of thinning, when polymers have become fully stretched, the filament becomes prone to instabilities, of which we describe two: A novel "breathing" instability, originating from the edge of t
O. Kiriyama
We describe the results of recent studies of a chromomagnetic instability and a gluonic phase in neutral two-flavor quark matter at nonzero temperature.
Abdelouahab Bibi, Abdelhakim Aknouche
This paper examines some probabilistic properties of the class of periodic GARCH processes (PGARCH) which feature periodicity in conditional heteroskedasticity. In these models, the parameters are allowed to switch between different regimes, so that their structure shares many properties with periodic ARMA process (PARMA). We examine the strict and second or
Abdehakim Aknouche, Abdelouhab Bibi
This paper establishes the strong consistency and asymptotic normality of the quasi-maximum likelihood estimator (QMLE) for a GARCH process with periodically time-varying parameters. We first give a necessary and sufficient condition for the existence of a strictly periodically stationary solution for the periodic GARCH (P-GARCH) equation. As a result, it is
Andreas Athenodorou, Barak Bringoltz, Michael Teper
We study the closed-string spectrum of SU(N) gauge theories in the fundamental representation in 2+1 dimensions. We calculate the energies of the lowest lying ~ 30 states using a large variety of operators characterised by the quantum numbers of parity and longitudinal momentum. We find that our results for the ground state are very well approximated by the
Sébastien Saugout, Eric Charron, Christian Cornaggia
The temporal dynamics of double ionization of H2 has been investigated both experimentally and theoretically with few-cycle laser pulses. The main observables are the proton spectra associated to the H^+ + H^+ fragmentation channel. The model is based on the time-dependent Schrödinger equation and treats on the same level the electronic and nuclear coordinat
Denis I. Saveliev
It is well-known that Choice and Regularity are independent of each other but have important common consequences of logical character (reflection principles, representations of classes by sets, etc.). We explain this phenomenon by isolating their "intersection", a principle (called here Best-Foundedness) which is consistent with the negations of both
Minimal surfaces in sub-Riemannian manifolds and structure of their singular sets in the (2,3) case
math.APNataliya Shcherbakova
We study minimal surfaces in generic sub-Riemannian manifolds with sub-Riemannian structures of co-rank one. These surfaces can be defined as the critical points of the so-called {\it horizontal} area functional associated to the canonical {\it horizontal} area form. We derive the intrinsic equation in the general case and then consider in greater detail 2-d
S. V. Lototsky, B. L. Rozovskii
We study stochastic evolution equations driven by Gaussian noise. The key features of the model are that the operators in the deterministic and stochastic parts can have the same order and the noise can be time-only, space-only, or space-time. Even the simplest equations of this kind do not have a square-integrable solution and must be solved in special weig
J. van Eymeren, D. J. Bomans, K. Weis, R. -J. Dettmar
Context: Hαimages of star bursting irregular galaxies reveal a large amount of extended ionized gas structures, in some cases at kpc-distance away from any place of current star forming activity. A kinematic analysis of especially the faint structures in the halo of dwarf galaxies allows insights into the properties and the origin of this gas component. This
J. B. Faes, M. Ploszajczak
A new parameter-free method is proposed for treatment of single-particle resonances in the real-energy continuum shell model. This method yields quasi-bound states embedded in the continuum which provide a natural generalization of weakly bound single-particle states.
F. Molitor, J. Güttinger, C. Stampfer, D. Graf
We have investigated the magnetotransport properties of a single-layer graphene Hall bar with additional graphene side gates. The side gating in the absence of a magnetic field can be modeled by considering two parallel conducting channels within the Hall bar. This results in an average penetration depth of the side gate created field of approx. 90 nm. The s
S. C. Tiwari
A critique on the interpretation of the double prism experiment on the evanescent microwave modes (arXiv:0708.0681) is presented. It is argued that these experiments do not give any evidence of superluminal photons. A physical mechanism based on the inhomogeneous waves of classical electromagnetic fields is proposed.
Jae Choon Cha
We employ Hirzebruch-type invariants obtained from iterated p-covers to investigate concordance of links and string links. We show that the invariants naturally give various group homomorphisms of the string link concordance group into L-groups over number fields. We also obtain homomorphisms of successive quotients of the Cochran-Orr-Teichner filtration. As
A. De Gregorio, S. M. Iacus
A one dimensional diffusion process $X=\{X_t, 0\leq t \leq T\}$, with drift $b(x)$ and diffusion coefficient $σ(θ, x)=\sqrtθ σ(x)$ known up to $θ>0$, is supposed to switch volatility regime at some point $t^*\in (0,T)$. On the basis of discrete time observations from $X$, the problem is the one of estimating the instant of change in the volatility structure
Calin Vamos, Stefan M. Soltuz, Maria Craciun
The stochastic processes of finite length defined by recurrence relations request additional relations specifying the first terms of the process analogously to the initial conditions for the differential equations. As a general rule, in time series theory one analyzes only stochastic processes of infinite length which need no such initial conditions and thei
Andreas Schutt, Peter J. Stuckey
Unit two-variable-per-inequality (UTVPI) constraints form one of the largest class of integer constraints which are polynomial time solvable (unless P=NP). There is considerable interest in their use for constraint solving, abstract interpretation, spatial databases, and theorem proving. In this paper we develop a new incremental algorithm for UTVPI constrai
M. V. Ioffe, D. N. Nishnianidze
The supersymmetric approach in the form of second order intertwining relations is used to prove the exact solvability of two-dimensional Schrodinger equation with generalized two-dimensional Morse potential for $a_0=-1/2$. This two-parametric model is not amenable to conventional separation of variables, but it is completely integrable: the symmetry operator