April 2008 arXiv papers — page 4

Michael Krivelevich, Eyal Lubetzky, Benny Sudakov

In this paper we analyze the appearance of a Hamilton cycle in the following random process. The process starts with an empty graph on n labeled vertices. At each round we are presented with K=K(n) edges, chosen uniformly at random from the missing ones, and are asked to add one of them to the current graph. The goal is to create a Hamilton cycle as soon as

Dirk Brommel, Meinulf Gockeler, Philipp Hagler, Roger Horsley

In recent years the investigation of hadron structure using lattice techniques has attracted growing attention. In this talk we give an overview on recent work with a focus on results for nucleon spectrum and structure from the QCDSF collaboration.

Pavel Krtous, Valeri P. Frolov, David Kubiznak

We prove that the most general solution of the Einstein equations with the cosmological constant which admits a principal conformal Killing-Yano tensor is the Kerr-NUT-(A)dS metric. Even when the Einstein equations are not imposed, any spacetime admitting such hidden symmetry can be written in a canonical form which guarantees the following properties: it is

Simon Wicks

A new examination of the GLV all-orders opacity result for radiative energy loss is presented. The opacity expansion is shown to be a Dyson expansion of a Schrodinger-like (or diffusion) equation, a form also found in BDMPS-Z-ASW, AMY and Higher Twist formalisms of radiative energy loss. A new, efficient numerical evaluation of the GLV all-orders result give

Chao Wang, Yijia Fan, Ioannis Krikidis, John S. Thompson

In this paper, a superposition-coded concurrent decode-and-forward (DF) relaying protocol is presented. A specific scenario, where the inter-relay channel is sufficiently strong, is considered. Assuming perfect source-relay transmissions, the proposed scheme further improves the diversity performance of previously proposed repetition-coded concurrent DF rela

J. Tõke, M. J. Quinlan, I. Pawelczak, W. U. Schröder

Characteristic signatures of statistical Coulomb fragmentation of highly excited nuclear systems were analyzed. It was found that in some important aspects, they coincide with perceived signatures of phase transitions in confined hypothetical pseudo-microcanonical systems, thus potentially giving rise to a false interpretation of experimental observations in

A. Derevianko, S. G. Porsev, K. Beloy

We present and analyze results of the relativistic coupled-cluster calculation of energies, hyperfine constants, and dipole matrix elements for the $2s$, $2p_{1/2}$, and $2p_{3/2}$ states of Li atom. The calculations are complete through the fourth order of many-body perturbation theory for energies and through the fifth order for matrix elements and subsume

Jan Tõke, Michael J. Quinlan, Wojtek Gawlikowicz, W. Udo Schröder

Performance of a simple method of particle identification via pulse rise time discrimination is demonstrated for slow pulses from charge-sensitive preamplifiers with rise times ranging from 10 ns to 500 ns. The method is based on a comparison of the amplitudes of two pulses, derived from each raw preamplifier pulse with two amplifiers with largely differing

Wlodzimierz Domanski, Andrew N. Norris

Transverse elastic waves behave differently in nonlinear isotropic and anisotropic media. Quadratically nonlinear coupling in the evolution equations for wave amplitudes is not possible in isotropic solids, but such a coupling may occur for certain directions in anisotropic materials. We identify the expression responsible for the coupling and we derive coup

M. J. Martinez Gonzalez, A. Asensio Ramos, T. A. Carroll, M. Kopf

Our main objective is to develop a denoising strategy to increase the signal to noise ratio of individual spectral lines of stellar spectropolarimetric observations. We use a multivariate statistics technique called Principal Component Analysis. The cross-product matrix of the observations is diagonalized to obtain the eigenvectors in which the original obse

Christian Kuehn

We introduce the basic concepts related to subharmonic functions and potentials, mainly for the case of the complex plane and prove the Riesz decomposition theorem. Beyond the elementary facts of the theory we deviate slightly from the usual path of exposition and introduce further concepts alongside with applications. We cover the Dirichlet problem in detai

E. H. Hwang, S. Das Sarma

Considering scattering by unintentional background charged impurities and by charged dopants in the modulation doping layer as well as by GaAs acoustic phonons, we theoretically consider the practical intrinsic (phonons) and extrinsic (background and dopants) limits to carrier mobility in modulation doped AlGaAs-GaAs 2D semiconductor structures. We find that

Vukosi Marivate, Tshilidzi Marwala

The use of computational intelligence techniques for classification has been used in numerous applications. This paper compares the use of a Multi Layer Perceptron Neural Network and a new Relational Network on classifying the HIV status of women at ante-natal clinics. The paper discusses the architecture of the relational network and its merits compared to

Manu Basavaraju, L. Sunil Chandran, Manoj Kummini

An $acyclic$ edge coloring of a graph is a proper edge coloring such that there are no bichromatic cycles. The \emph{acyclic chromatic index} of a graph is the minimum number k such that there is an acyclic edge coloring using k colors and is denoted by $a'(G)$. It was conjectured by Alon, Sudakov and Zaks (and earlier by Fiamcik) that $a'(G)\le Δ+2$

J. P. Cassinelli, R. Ignace, W. L. Waldron, J. Cho

It is now well established that stellar winds of hot stars are fragmentary and that the X-ray emission from stellar winds has a strong contribution from shocks in winds. Chandra high spectral resolution observations of line profiles of O and B stars have shown numerous properties that had not been expected. Here we suggest explanations by considering the X-r

Melanie Matchett Wood

Bhargava proved a formula for counting, with certain weights, degree n etale extensions of a local field, or equivalently, local Galois representations to S_n. This formula is motivation for his conjectures about the density of discriminants of S_n-number fields. We prove there are analogous ``mass formulas'' that count local Galois representations t

Xiaoming Sun, Sasa Zaric, Dan Daranciang, Kevin Welsher

Single-walled carbon nanotubes (SWNTs) are typically long (>100 nm) and have been well established as novel quasi one-dimensional systems with interesting electrical, mechanical, and optical properties. Here, quasi zero-dimensional SWNTs with finite lengths down to the molecular scale (7.5 nm in average) were obtained by length separation using a density gra

P. Bicudo

We review chiral symmetry breaking at the BCS level, in the framework of chiral invariant quark models and in the Schwinger-Dyson formalism. We revisit the pi mass problem beyond the BCS level. We show a theorem on the masses, on the widths and on the q qbar content of the scalar mesons sigma and f0.

B. P. Bonev, M. J. Mumma, Y. L. Radeva, M. A. DiSanti

We report measurements of eight native (i.e., released directly from the comet nucleus) volatiles (H2O, HCN, CH4, C2H2, C2H6, CO, H2CO, and CH3OH) in comet 8P/Tuttle using NIRSPEC at Keck 2. Comet Tuttle reveals a truly unusual composition, distinct from that of any comet observed to date at infrared wavelengths. The prominent enrichment of methanol relative

K. P. Khemchandani, A. Martínez Torres, E. Oset

We study the $ππN$ system by solving the Faddeev equations, for which the input two-body $t$-matrices are obtained by solving the Bethe-Salpeter equation in the coupled channel formalism. The potentials for the $ππ$, $πN$ sub-systems and their coupled channels are obtained from chiral Lagrangians, which have been earlier used to study resonances in these sys

Gabriel F. Calvo, Antonio Picón, Roberta Zambrini

We put forward a method that allows the experimental determination of the entire spatial mode spectrum of any arbitrary monochromatic wave field in a plane normal to its propagation direction. For coherent optical fields, our spatial spectrum analyzer can be implemented with a small number of benchmark refractive elements embedded in a single Mach-Zehnder in

A. Gurevich, V. M. Vinokur

We show that the size effects radically affect the electric field-current ($E-I$) relation of superconducting films. We calculate $E(J)$ due to thermally-activated hopping of single vortices driven by current $I$ across the film in a magnetic field $H$, taking into account interaction of free vortices with their antivortex images and peaks in the Meissner cu

R. Berinde, A. C. Gilbert, P. Indyk, H. Karloff

There are two main algorithmic approaches to sparse signal recovery: geometric and combinatorial. The geometric approach starts with a geometric constraint on the measurement matrix and then uses linear programming to decode information about the signal from its measurements. The combinatorial approach constructs the measurement matrix and a combinatorial de

A. Noriega-Crespo, D. C. Hines, K. Gordon, F. R. Marleau

We present Spitzer observations of IC 443 obtained with MIPS and IRS as part of our GTO program on the astrophysics of ejecta from evolved stars. We find that the overall morphology at mid/far IR wavelengths resembles even more closely a loop or a shell than the ground based optical and/or near IR images.The dust temperature map, based on the 70/160micron ra

Mithat Unsal

We prove the absence of a mass gap and confinement in the Polyakov model with massless complex fermions in any representation of the gauge group. A $U(1)_{*}$ topological shift symmetry protects the masslessness of one dual photon. This symmetry emerges in the IR as a consequence of the Callias index theorem and abelian duality. For matter in the fundamental

Carlo Hamalainen, Nicholas J. Cavenagh

In this note we give two results. First, if a latin bitrade $(T_1, T_2)$ is primary, thin, separated, and the autotopism group of $T_1$ acts regularly on $T_1$, then $(T_1, T_2)$ may be derived from a group-based construction. Second, if a latin bitrade $(T_1, T_2)$ has genus 0 then the disjoint mate $T_2$ is unique and the autotopism group of $T_1$ is equal

Yijia Fan, Lifeng Lai, Elza Erkip, H. Vincent Poor

In this paper the performance limits and design principles of rateless codes over fading channels are studied. The diversity-multiplexing tradeoff (DMT) is used to analyze the system performance for all possible transmission rates. It is revealed from the analysis that the design of such rateless codes follows the design principle of approximately universal

S. Skupin, M. Grech, W. Krolikowski

We discuss generic properties of rotating nonlinear wave solutions, the so called azimuthons, in nonlocal media. Variational methods allow us to derive approximative values for the rotating frequency, which is shown to depend crucially on the nonlocal response function. Further on, we link families of azimuthons to internal modes of classical non-rotating st

Robert W. Easton

We analyze flat S_3-covers, attempting to create structures parallel to those found in the abelian theory. We use an initial local analysis as a guide in finding a global description.

Rebecca Lehman

The classical Brill-Noether theorems count the dimension of the family of maps from a general curve of genus g to non-degenerate curves of degree d in r-dimensional projective space. These theorems can be extended to include ramification conditions at fixed general points. This paper deals with the problem of imposing a ramification condition at an unspecifi

Antony Valentini

The hypothesis of quantum nonequilibrium at the big bang is shown to have observable consequences. For a scalar field on expanding space, we show that relaxation to quantum equilibrium (in de Broglie-Bohm theory) is suppressed for field modes whose quantum time evolution satisfies a certain inequality, resulting in a 'freezing' of early quantum noneq

V. L. Gurevich, M. I. Muradov

Spin-magnetophonon level splitting in a quantum well made of a semimagnetic wide gap semiconductor is considered. The semimagnetic semiconductors are characterized by a large effective $g$ factor. The resonance conditions $\hbarω_{\rm LO}=μ_BgB$ for the spin flip between two Zeeman levels due to interaction with longitudinal optical phonons can be achieved s

Basilio X. Santiago, Tibério B. Vale

There is a clear scarcity of structural parameters for stellar thick discs, especially for spiral galaxies located in high-density regions, such as galaxy clusters and compact groups. We have modelled the thin and thick discs of 4 edge-on spirals located in Abell clusters: NGC 705, ESO243G49, ESO187G19, LCSBS0496P. Deep I band images of NGC 705 were taken fr

Rene D. Rohrmann, Miguel Robles, Mariano Lopez de Haro, Andres Santos

A recently derived method [R. D. Rohrmann and A. Santos, Phys. Rev. E. {\bf 76}, 051202 (2007)] to obtain the exact solution of the Percus-Yevick equation for a fluid of hard spheres in (odd) $d$ dimensions is used to investigate the convergence properties of the resulting virial series. This is done both for the virial and compressibility routes, in which t

L. Hindson, R. Napiwotzki, U. Heber, M. Lemke

The Gaia mission will provide an unprecedented 3D view of our galaxy, it will obtain astrometric, photometric and spectrographic data for roughly one billion stars. We are particularly interested in the treasure chest of new data Gaia will produce for hot subdwarf B (sdB) stars. In order for Gaia to classify sdBs and estimate parameters model spectra coverin

V. Ossenkopf, M. Krips, J. Stutzki

The Delta-variance analysis, has proven to be an efficient and accurate method of characterising the power spectrum of interstellar turbulence. The implementation presently in use, however, has several shortcomings. We propose and test an improved Delta-variance algorithm for two-dimensional data sets, which is applicable to maps with variable error bars and

G. Kerkyacharian, P. Petrushev, D. Picard, Yuan Xu

A pair of dual frames with almost exponentially localized elements (needlets) are constructed on $\RR_+^d$ based on Laguerre functions. It is shown that the Triebel-Lizorkin and Besov spaces induced by Laguerre expansions can be characterized in terms of respective sequence spaces that involve the needlet coefficients.

Daniel J. Price, Matthew R. Bate, Clare L. Dobbs

Magnetic fields are important at every scale in the star formation process: from the dynamics of the ISM in galaxies, to the collapse of turbulent molecular clouds to form stars and in the fragmentation of individual star forming cores. The recent development of a robust algorithm for MHD in the Smoothed Particle Hydrodynamics method has enabled us to perfor

Himanshu Jain, A. K. Raychaudhuri

We show that strong non--linear electron transport in the ferromagnetic insulating (FMI) state of manganites, responsible for phenomena such as colossal electroresistance and current induced resistance switching, can occur due to a hot electron effect. In the FMI state, which we show is an insulator with a Coulomb gap, the temperature of the electron and lat

Vladislav Prytula, Vadym Vekslerchik, Victor M. Perez-Garcia

In this paper we study blow-up phenomena in general coupled nonlinear Schrodinger equations with different dispersion coefficients. We find sufficient conditions for blow-up and for the existence of global solutions. We discuss several applications of our results to heteronuclear multispecies Bose-Einstein condensates and to degenerate boson-fermion mixtures

Walter D Neumann, Jonathan Wahl

We prove the "End Curve Theorem," which states that a normal surface singularity $(X,o)$ with rational homology sphere link $Σ$ is a splice-quotient singularity if and only if it has an end curve function for each leaf of a good resolution tree. An "end-curve function" is an analytic function $(X,o)\to (\C,0)$ whose zero set intersects $Σ$ in

Nicolas Douguet, Viatcheslav Kokoouline, Chris H. Greene

The article presents an improved theoretical description of dissociative recombination of HCO$^+$ and DCO$^+$ ions with a low energy electron. In the previous theoretical study (Phys. Rev. A {\bf 74}, 032707) on HCO$^+$, the vibrational motion along the CO coordinate was neglected. Here, all vibrational degrees of freedom, including the CO stretch coordinate

Konstantine Zelator

Each triangle has three exterior or external circles tangential to the three straight lines containing the three sides of the triangle.Among the preliminaries in this paper, is deriving formulas for the radii of the three exterior circles in terms of the triangle's sidelengths. After that we focus on Heron triangles. Heron triangles are known in the lite

Enrico Vesperini, David M. Goldberg, Stephen L. W. McMillan, James Dura

The advent of affordable parallel computers such as Beowulf PC clusters and, more recently, of multi-core PCs has been highly beneficial for a large number of scientists and smaller institutions that might not otherwise have access to substantial computing facilities. However, there has not been an analogous progress in the development and dissemination of p

Peter M. Makienko

Let $ R $ be a rational map. We are interesting in the dynamic of the Ruelle operator on suitable spaces of differentials. In particular the necessary and sufficient conditions (in terms of convergence of sequences of measures) of existence of invariant conformal structures on $ J(R) $ are obtained.

G. Pacelli Bessa, M. Silvana Costa

We give lower bounds for the fundamental tone of open sets in submanifolds with locally bounded mean curvature in $ N \times \mathbb{R}$, where $N$ is an $n$-dimensional complete Riemannian manifold with radial sectional curvature $K_{N} \leq \kappa$. When the immersion is minimal our estimates are sharp. We also show that cylindrically bounded minimal surfa

Roberto Monetti, Wolfram Bunk, Ferdinand Jamitzky

We present a methodology to characterize synchronization in time series based on symbolic representations. A symbol is linked to a sequence of numbers through the rank-order of its values. A representation of a time series results after mapping all sequences into symbols. We propose a transcription scheme between symbolic representations to study the dynamic

Peter M. Frinchaboy, Steven R. Majewski

We have begun a survey of the chemical and dynamical properties of the Milky Way disk as traced by open star clusters. In this first contribution, the general goals of our survey are outlined and the strengths and limitations of using star clusters as a Galactic disk tracer sample are discussed. We also present medium resolution (R ~ 15,0000) spectroscopy of

Manik Lal Das

Recently, Rawat and Saxena proposed a method for protecting data using ``Disclaimer Statement''. This paper presents some issues and several flaws in their proposal.

Nicolas Labrosse, Jean-Claude Vial, Pierre Gouttebroze

In this study we show how hydrogen and helium lines modelling can be used to make a diagnostic of active and eruptive prominences. One motivation for this work is to identify the physical conditions during prominence activation and eruption. Hydrogen and helium lines are key in probing different parts of the prominence structure and inferring the plasma para

Koichiro Sugiyama, Kenta Fujisawa, Akihiro Doi, Mareki Honma

We present the results of daily monitoring of 6.7 GHz methanol maser in Cepheus A (Cep A) using Yamaguchi 32-m radio telescope as well as the results of imaging observations conducted with the JVN (Japanese VLBI Network). We indentified five spectral features, which are grouped into red-shifted (-1.9 and -2.7 km/s) and blue-shifted (-3.8, -4.2, and -4.9 km/s

Florian Fröwis, Gebhard Grübl, Markus Penz

Fleming's inequality is generalized to the decay function of mixed states. We show that for any symmetric hamiltonian $h$ and for any density operator $ρ$ on a finite dimensional Hilbert space with the orthogonal projection $Π$ onto the range of $ρ$ there holds the estimate $\Tr(Π\rme^{-\rmi ht}ρ\rme^{\rmi ht}) \geq\cos^{2}((Δh)_ρt) $ for all real $t$ wi

Tao-Ming Wang, Jun-Lin Kuo

A multifamily set representation of a finite simple graph $G$ is a multifamily $\mathcal{F}$ of sets (not necessarily distinct) for which each set represents a vertex in $G$ and two sets in $\mathcal{F}$ intersects if and only if the two corresponding vertices are adjacent. For a graph $G$, an \textit{edge clique covering} (\textit{edge clique partition}, re

Maria Vallarino

Let S be the semidirect product of R^d and R^+ endowed with the Riemannian symmetric space metric and the right Haar measure: this is a Lie group of exponential growth. In this paper we define an Hardy space H^1 and a BMO space in this context. We prove that the functions in BMO satisfy the John-Nirenberg inequality and that BMO may be identified with the du

Fritz Rohrlich

Using physical arguments, I derive the physically correct equations of motion for a classical charged particle from the Lorentz-Abraham-Dirac equations (LAD) which are well known to be physically incorrect. Since a charged particle can classically not be a point particle because of the Coulomb field divergence, my derivation accounts for that by imposing a b

Karlheinz Gröchenig, Yurii Lyubarskii

We investigate vector-valued Gabor frames (sometimes called Gabor superframes) based on Hermite functions $H_n$. Let $h= (H_0, H_1, ..., H_n)$ be the vector of the first $n+1$ Hermite functions. We give a complete characterization of all lattices $Λ\subseteq \bR ^2$ such that the Gabor system $\{e^{2πi λ_2 t} \boh (t-λ_1): λ= (λ_1, λ_2) \in Λ\}$ is a frame f

A. Emmanouilidou, T. Uzer

We investigate the response of two three-body Coulomb systems when driven by attosecond half-cycle pulses: The hydrogen molecular ion and the helium atom. Using very short half-cycle pulses (HCPs) which effectively deliver ``kicks'' to the electrons, we first study how a carefully chosen sequence of HCPs can be used to control to which of one of the

F. Rodler, M. Kuerster, T. Henning

Aims. We attempt to detect starlight reflected from a hot Jupiter, orbiting the main-sequence star HD 75289Ab. We report a revised analysis of observations of this planetary system presented previously by another research group. Methods. We analyse high-precision, high-resolution spectra, collected over four nights using UVES at the VLT/UT2, by way of data s

Mary Crone Odekon

The autocorrelation function provides an objective test for the existence of special scales in the hierarchical clustering of young stars. We apply this measure to single-star photometry for the brightest main sequence stars in the Small Magellanic Cloud (SMC), the Large Magellanic Cloud (LMC), M33, and M31, using data from the Magellanic Clouds Photometric

Taekyun Kim

The main purpose of this paper is to prove an identity of symmetry for the Frobenius-Euler polynomials.

M. Eroms, L. Mayrhofer, M. Grifoni

Linear transport through a single-walled carbon nanotube ring (CNR), pierced by a magnetic field and capacitively coupled to a gate voltage source, is investigated starting from a model of interacting $p_z$-electrons. The dc-conductance, calculated in the limit of weak tunneling between the ring and the leads, displays a periodic resonance pattern determined

James F. Lutsko

Previously, it has been shown that the direct correlation function for a Lennard-Jones fluid could be modeled by a sum of that for hard-spheres, a mean-field tail and a simple linear correction in the core region constructed so as to reproduce the (known) bulk equation of state of the fluid(Lutsko, JCP 127, 054701 (2007)). Here, this model is combined with i

H. Henry

In this study, the phase field model of crack propagation is used to study the dynamic branching instability in the case of inplane loading in two dimensions. Simulation results are in good agreement with theoretical predictions and experimental findings. Namely, the critical speed at which the instability starts is about $0.48 c_s$. They also show that a fu

Masaaki Nakamura, Lila Hirasawa, Ken-Ichiro Imura

We discuss the quantum Hall effect of bilayer graphene with finite gate voltage where the Fermi energy exceeds the interlayer hopping energy. We calculated magnetic susceptibility, diagonal and off-diagonal conductivities in finite-magnetic-field formalism, and observed crossover of integer quantum Hall effect from two independent monolayer type system to st

G. Pagliaroli, M. L. Costantini, F. Vissani

We study SN1987A neutrino events through a likelihood analysis with one-component (cooling) and two-component (accretion and cooling) emission model. We show that there is a 3.2 sigma hint for the initial accretion phase.

F. P. Israel, D. Raban, R. S. Booth, F. T. Rantakyro

In a study of the radio emission mechanism of the FR-I AGN NGC 5128 (Centaurus A)}, we have determined the centimeter and millimeter continuum spectrum of the whole Centaurus A radio source and measured the continuum emission from the active galxy nucleus at various times between 1989 and 2005 at frequencies between 86 GHz (3.5 mm) and 345 GHz (0.85 mm). The

Alejandro Ibarra, David Tran

The scenario of gravitino dark matter with broken R-parity naturally reconciles three paradigms that, albeit very well motivated separately, seem to be in mutual conflict: supersymmetric dark matter, thermal leptogenesis and standard Big Bang nucleosynthesis. Interestingly enough, the products of the gravitino decay could be observed, opening the possibility

Eylee Jung, Mi-Ra Hwang, DaeKil Park, Jin-Woo Son

The quantum teleportation with noisy EPR state is discussed. Using an optimal decomposition technique, we compute the concurrence, entanglement of formation and Groverian measure for various noisy EPR resources. It is shown analytically that all entanglement measures reduce to zero when $\bar{F} \leq 2/3$, where $\bar{F}$ is an average fidelity between Alice

Rainer Beck

The origin of magnetic fields in the Universe is an open problem in astrophysics and fundamental physics. "Cosmic Magnetism" has been accepted as Key Science Project both for the Low Frequency Array (LOFAR, under construction) and the planned Square Kilometre Array (SKA). At low frequencies LOFAR and SKA will allow to map the structure of weak magnet

G. Lewis, Z. Moktadir, C. Gollasch, M. Kraft

Ultra-cold atoms can be manipulated using microfabricated devices known as atom chips. These have significant potential for applications in sensing, metrology and quantum information processing. To date, the chips are loaded by transfer of atoms from an external, macroscopic magneto-optical trap (MOT) into microscopic traps on the chip. This transfer involve

Dmitry A. Zezyulin, Georgy L. Alfimov, Vladimir V. Konotop, Victor M. Perez-Garcia

We analyze the stability of non-ground nonlinear states of a Bose-Einstein condensate in the mean field limit in effectively 1D (``cigar-shape'') traps for various types of confining potentials. We find that nonlinear states become, in general, more stable when switching from a harmonic potential to an anharmonic one. We discuss the relation between

P. J. Baker, T. Lancaster, S. J. Blundell, W. Hayes

We report muon spin relaxation measurements on two Ti3+ containing perovskites, LaTiO3 and YTiO3, which display long range magnetic order at low temperature. For both materials, oscillations in the time-dependence of the muon polarization are observed which are consistent with three-dimensional magnetic order. From our data we identify two magnetically inequ

Heithem Abbes, Christophe Cérin, Jean-Christophe Dubacq, Mohamed Jemni

The Desktop Grid offers solutions to overcome several challenges and to answer increasingly needs of scientific computing. This technology consists mainly in exploiting PC resources, geographically dispersed, to treat time consuming applications and/or important storage capacity requiring applications. However, as resources number increases, the need for sca

P. Herskind, A. Dantan, M. B. Langkilde-Lauesen, A. Mortensen

We report on the loading of large ion Coulomb crystals into a linear Paul trap incorporating a high-Finesse optical cavity (F~3200). We show that, even though the 3-mm diameter dielectric cavity mirrors are placed between the trap electrodes and separated by only 12 mm, it is possible to produce in situ ion Coulomb crystals containing more than 100.000 calci

Caucher Birkar

We prove the termination of 4-fold log flips for klt pairs of Kodaira dimension $κ\ge 2$.

S. Komossa, H. Zhou, H. Lu

We present SDSSJ092712.65+294344.0 as the best candidate to date for a recoiling supermassive black hole (SMBH). SDSSJ0927+2943 shows an exceptional optical emission-line spectrum with two sets of emission lines: one set of very narrow emission lines, and a second set of broad Balmer and broad high-ionization forbidden lines which are blueshifted by 2650 km\

Sylvain Schmitz, Joseph Le Roux

The derivation trees of a tree adjoining grammar provide a first insight into the sentence semantics, and are thus prime targets for generation systems. We define a formalism, feature-based regular tree grammars, and a translation from feature based tree adjoining grammars into this new formalism. The translation preserves the derivation structures of the or

L. G. Dedenko, D. A. Podgrudkov, T. M. Roganova, G. F. Fedorova

The pointing directions of extensive air showers observed at the Pierre Auger Observatory were fitted within 3.1 degree with positions of the nearby active galactic nuclei from the Veron-Cetty and P. Veron catalog. The cosmic ray luminosity of the active galactic nuclei which happened to be a source of the particular cosmic ray event constitutes a fraction ~

R. Smith, M. C. Wyatt, W. R. F. Dent

(ABRIDGED) Studies of debris disks have shown that most systems are analogous to the Edgeworth-Kuiper Belt. However a rare subset of sun-like stars possess dust which lies in the terrestrial planet region. In this study we aim to determine how many sources with apparent mid-IR excess are truly hosts of warm dust, and investigate where the dust must lie. We o

E. Caliceti, S. Graffi

Consider in $L^2(\R)$ the \Sc operator family $H(g):=-d^2_x+V_g(x)$ depending on the real parameter $g$, where $V_g(x)$ is a complex-valued but $PT$ symmetric periodic potential. An explicit condition on $V$ is obtained which ensures that the spectrum of $H(g)$ is purely real and band shaped; furthermore, a further condition is obtained which ensures that th

D. Klammer, F. Schrempp

In this paper, we explore the appealing possibility that the strong suppression of large-size QCD instantons - as evident from lattice data - is due to a surviving conformal space-time inversion symmetry. This symmetry is both suggested from the striking invariance of high-quality lattice data for the instanton size distribution under inversion of the instan

Vyacheslav Kulagin

We consider the notions of topological essential range and regularity for continuous cocycles over minimal $\Z$-systems introduced in \cite{GH} and discuss relations with their generic counterparts. The alternative generic definitions can be given by using the notion of generic Mackey action associated with a cocycle. We further present a description of recu

N. A. Pertsev

It is shown theoretically that a giant magnetoelectric susceptibility exceeding 10^-6 s/m may be achieved in the ferromagnetic/ferroelectric epitaxial systems via the magnetization rotation induced by an electric field applied to the substrate. The predicted magnetoelectric anomaly results from the strain-driven spin-reorientation transitions in ferromagneti

B. Garilli, O. Le Fèvre, L. Guzzo, D. Maccagni

The VVDS-Wide survey has been designed with the general aim of tracing the large-scale distribution of galaxies at z~1 on comoving scales reaching ~100Mpc/h, while providing a good control of cosmic variance over areas as large as a few square degrees. This is achieved by measuring redshifts with VIMOS at the ESO VLT to a limiting magnitude I_AB=22.5, target

Marko Härtelt, Bretislav Friedrich

We show that combined electrostatic and radiative fields can greatly amplify the directional properties, such as axis orientation and alignment, of symmetric top molecules. In our computational study, we consider all four symmetry combinations of the prolate and oblate inertia and polarizability tensors, as well as the collinear and perpendicular (or tilted)

Kenji Bekki, Masashi Chiba

Recent observations of the Small Magellanic Cloud (SMC) have revealed that the HI gas shows a significant amount of rotation (V_c 60 km/s), while no or little rotation is evident for the old stellar populations. We suggest that this unique kinematical difference between these components in the SMC can be caused by a major merger event which occurred in the e

Juan A. Bonachela, Haye Hinrichsen, Miguel A. Munoz

Estimating entropies from limited data series is known to be a non-trivial task. Naive estimations are plagued with both systematic (bias) and statistical errors. Here, we present a new 'balanced estimator' for entropy functionals Shannon, Rényi and Tsallis) specially devised to provide a compromise between low bias and small statistical errors, for

Jacco Th. van Loon, Martha L. Boyer, Iain McDonald

We use archival Spitzer Space Telescope photometry of the old, super-solar metallicity massive open cluster NGC 6791 to look for evidence of enhanced mass loss, which has been postulated to explain the optical luminosity function and low white dwarf masses in this benchmark cluster. We find a conspicuous lack of evidence for prolificacy of circumstellar dust

Christine Nattrass

Two particle azimuthal correlations with strange trigger particles ($K^0_S,Λ,Ξ$) are presented in Cu+Cu and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV in STAR at RHIC. The near-side associated yield is investigated as a function of centrality, $p_T$, and strangeness content of the trigger to investigate possible flavour or meson/baryon differences. The sy

Bjoern Schenke, Adrian Dumitru, Yasushi Nara, Michael Strickland

We present numerical simulations of the SU(2) Boltzmann-Vlasov equation including both hard elastic particle collisions and soft interactions mediated by classical Yang-Mills fields. We provide an estimate of the coupling of jets to a hot isotropic plasma, which is independent of infrared cutoffs. In addition, we investigate jet propagation in anisotropic pl

Nestor Sanchez, Emilio J. Alfaro

It is known that the gas has a fractal structure in a wide range of spatial scales with a fractal dimension that seems to be a constant around Df = 2.7. It is expected that stars forming from this fractal medium exhibit similar fractal patterns. Here we address this issue by quantifying the degree to which star-forming events are clumped. We develop, test, a

Lyuba Malysheva, Alexander Onipko

Origin of the spectrum of $π$ electrons that results from coupling of $N$ $\cal N$-long acenes via C-C covalent bonding have been traced with the use of the Green function formalism. Exact expressions of acene and graphene Green's functions, which are useful for analysis of electronic properties of these macromolecules, are obtained and advanced to the f

Vladik A. Avetisov, Albert Kh. Bikulov

A simple and surprisingly accurate description of spectral diffusion in deeply frozen globular proteins is constructed directly using the concept of ultrametricity of protein dynamics. Earlier the similar concept has been used for successful description of ligand-rebinding kinetics of myoglobin at temperatures about of 200 K. Hence the ultrametricity offers

Lajos Soukup

We give a negative answer to a question of Erdos and Hajnal: it is consistent that GCH holds and there is a colouring $c:[{ω_2}]^2\to 2$ establishing $ω_2 \not\to [(ω_1;ω)]^2_2$ such that some colouring $g:[ω_1]^2\to 2$ can not be embedded into $c$. It is also consistent that $2^{ω_1}$ is arbitrarily large, and a function $g$ establishes $2^{ω_1} \not\to [(ω

S. -J. Paardekooper, J. C. B. Papaloizou

We study the disc planet interactions of low-mass protoplanets embedded in a circumstellar disc. We extend the standard theory of planet migration from the usual locally isothermal assumption to include non-barotropic effects, focusing on the validity of linear theory. We compared solutions of the linear equations with results from non-linear hydrodynamic si

V. L. Kozhevnikov, O. N. Leonidova, A. L. Ivanovskii, I. R Shein

Here we report on synthesis and characterization of a new member LaO1-deltaNiBi in the family of novel superconductors. Though the onset superconducting temperature ~4 K is smaller compared to 55 K that has been achieved already in SmO1-deltaFeAs the similarities in crystalline structure, elec-tronic properties and low-temperature electron transport features

Woon Ih Choi, Jisoon Ihm, Gunn Kim

We present the first-principles study of effects of the charge dopants such as Cesium and Iodine encapsulated on the electronic structure of carbon nanotubes. An encapsulated cesium atom donates an electron to the nanotube and produces donor-like states below the conduction bands. In contrast, an iodine trimer (I$_{3}$) accepts an electron from the nanotube

M. D. Filipovic, S. Ognjanovic, M. Ognjanovic

This is initial study of a gene signatures responsible for adapting microscopic life to the life in extreme Earth environments. We present a results on ID of the clusters of COGs common to several hyperthermophiles and exclusion of those common to a mesophile: E.coli.K12, will yield a group of proteins possibly involved in adaptation to life under extreme T.

M. J. Woolley, G. J. Milburn, Carlton M. Caves

We consider a nanomechanical analogue of a nonlinear interferometer, consisting of two parallel, flexural nanomechanical resonators, each with an intrinsic Duffing nonlinearity and with a switchable beamsplitter-like coupling between them. We calculate the precision with which the strength of the nonlinearity can be estimated and show that it scales as $1/n^

J. L. Payne, M. D. Filipović, E. J. Crawford, A. Y. De Horta

We present preliminary results from spectral observations of four candidate radio sources co-identified with known planetary nebulae (PNe) in the Small Magellanic Cloud (SMC). These were made using the Radcliffe 1.9-meter telescope in Sutherland, South Africa. These radio PNe were originally found in Australia Telescope Compact Array (ATCA) surveys of the SM