February 2009 arXiv papers — page 40

S. Alexakis, A. D. Ionescu, S. Klainerman

We prove the existence of a Hawking Killing vector-field in a full neighborhood of a local, regular, bifurcate, non-expanding horizon embedded in a smooth vacuum Einstein space-time. We do not assume analyticity of the space-time. This result will be applied in a second paper to prove a perturbative version of the uniqueness of smooth, stationary black holes

James G. Analytis, Ross D. McDonald, Jiun-Haw Chu, Scott C. Riggs

We report quantum oscillation measurements that enable the direct observation of the Fermi surface of the low temperature ground state of \ba122. From these measurements we characterize the low energy excitations, revealing that the Fermi surface is reconstructed in the antiferromagnetic state, but leaving itinerant electrons in its wake. The present measure

Brandon Bozek, Andreas Albrecht, Daniel Phillips

Current cosmological observations indicate a preference for a cosmological constant that is drastically smaller than what can be explained by conventional particle physics. The Causal Entropic Principle (Bousso, {\it et al}.) provides an alternative approach to anthropic attempts to predict our observed value of the cosmological constant by calculating the e

Gagan Raj Gupta, Sujay Sanghavi, Ness B. Shroff

This paper proposes a new class of online policies for scheduling in input-buffered crossbar switches. Our policies are throughput optimal for a large class of arrival processes which satisfy strong-law of large numbers. Given an initial configuration and no further arrivals, our policies drain all packets in the system in the minimal amount of time (providi

Xiaobing Feng, Michael Neilan

In this paper we develop two conforming finite element methods for a fourth order bi-wave equation arising as a simplified Ginzburg-Landau-type model for d-wave superconductors in absence of applied magnetic field. Unlike the biharmonic operator $Δ^2$, the bi-wave operator $\Box^2$ is not an elliptic operator, so the energy space for the bi-wave equation is

Nikolai G. Kalugin, Yuri V. Rostovtsev

It is strong Coulomb effects in carbon nanotubes that lead to formation of the so-called "bright" and "dark" (forbidden one-photon optical transition) exciton states, and dramatically decrease the efficiency of one-photon light emission via trapping of the carriers by "dark" states. We demonstrate that the proper use of these "bri

Rudolph E. Schild, Justin Lovegrove, Pavlos Protopapas

We examine the nature of brightness fluctuations in the UV-Optical spectral region of an ordinary quasar with 881 optical brightness measurements made during the epoch 1993 - 1999. We find evidence for systematic trends having the character of a pattern of reverberations following an initial disturbance. The initial pulses have brightness increases of order

J. M. Benko, S. Barcza

The first UBV(RI)_C time series photometry of the RRd star V372 Ser is presented to determine some parameters of the star. In April, May 2007 2812 U, B, V, R_C, I_C frames were obtained at Konkoly and Teide Observatories, 1508 V observations were collected from the literature. Fourier fitted light curves have been derived in all bands. The non-linearly coupl

S. S. Kutateladze

Under study is the new class of geometrical extremal problems in which it is required to achieve the best result in the presence of conflicting goals; e.g., given the surface area of a convex body $\mathfrak x$, we try to maximize the volume of $\mathfrak x$ and minimize the width of $\mathfrak x$ simultaneously. These problems are addressed along the lines

V. Straizys, R. Lazauskaite

The band-width effect on interstellar reddening lines in the J-H vs. H-K_s diagram of the 2MASS survey is investigated using synthetic color indices and color excesses based on the Kurucz model atmospheres. At large interstellar reddenings (E(H-K_s) larger than 1.0) reddening lines deviate considerably from a straight line. The lines can be approximated by a

Dongho Chae

In this paper we prove nonexistence of stationary weak solutions to the Euler-Poisson equations and the Navier-Stokes-Poisson equations in $\Bbb R^N$, $N\geq 2$, under suitable assumptions of integrability for the density, velocity and the potential of the force field. For the time dependent Euler-Poisson equations we prove nonexistence result assuming addit

S. Albeverio, Sh. A. Ayupov, A. A. Rakhimov, R. A. Dadakhodjaev

For real factors the notions of the coupling constant and the index are introduced and investigated. The possible values of the index for type II$_1$ real factors are calculated, in a similar way as for the complex case.

Sergio Rojas

The amount of published research in Physics Education Research (PER) shows, on one hand, an increasing interest in the design and development of high performance physics teaching strategies, and, on the other hand, it tries to understand plausible ways on which the brain processes scientific information so that scientific thinking skills could be taught more

B. Haskell, N. Andersson, A. Passamonti

We develop a new perturbative framework for studying the r-modes of rotating superfluid neutron stars. Our analysis accounts for the centrifugal deformation of the star, and considers the two-fluid dynamics at linear order in the perturbed velocities. Our main focus is on a simple model system where the total density profile is that of an $n=1$ polytrope. We

Zeynep Kurban, Arthur Lovell, Derek Jenkins, Steve Bennington

Homogenous graphitic nanofibres (GNFs) have been synthesised by heat treatment of electrospun polyacrylonitrile in dimethylsulphoxide, offering a new solution route of low toxicity to manufacture sub-60 nm diameter GNFs. Fibre beading resulting from the spinning of low-concentration polymer solutions can be reduced with the addition of surfactant or sodium c

Friedwardt Winterberg

The recently proposed Super Marx generator pure deuterium micro-detonation ignition concept is compared to the Lawrence Livermore National Ignition Facility (NIF) Laser DT fusion-fission hybrid concept (LiFE) [1]. In a Super Marx generator a large number of ordinary Marx generators charge up a much larger second stage ultra-high voltage Marx generator, from

E. Z. Kurmaev, J. A. McLeod, A. Buling, N. A. Skorikov

We present density functional theory (DFT) calculations and a full set of X-ray spectra (resonant inelastic X-ray scattering and X-ray photoelectron spectra) measurements of single crystal CaFe2As2. The experimental valence band spectra are consistent with our DFT calculations. Both theory and experiment show that the Fe 3d-states dominate the Fermi level an

Dilip G. Banhatti

The classical cosmological V/Vm-test is introduced and elaborated. Use of the differential distribution p(V/Vm) of the V/Vm-variable rather than just the mean <V/Vm> leads directly to the cosmological number density without any need for assumptions about the cosmological evolution of the underlying (quasar) population. Calculation of this number density n(z)

K. Kanakoglou, C. Daskaloyannis

Parabosonic algebra in finite or infinite degrees of freedom is considered as a $\mathbb{Z}_{2}$-graded associative algebra, and is shown to be a $\mathbb{Z}_{2}$-graded (or: super) Hopf algebra. The super-Hopf algebraic structure of the parabosonic algebra is established directly without appealing to its relation to the $osp(1/2n)$ Lie superalgebraic struct

Orsola De Marco

Planetary nebulae (PNe) are circumstellar gas ejected during an intense mass-losing phase in the the lives of asymptotic giant branch stars. PNe have a stunning variety of shapes, most of which are not spherically symmetric. The debate over what makes and shapes the circumstellar gas of these evolved, intermediate mass stars has raged for two decades. Today

Stuart Armstrong

Complementing the previous paper in the series, this paper classifies $|2|$-graded parabolic geometries, listing their important properties: the group $G_0$, the graded tangent bundle $gr(T)$ and its algebraïc bracket, the relevant cohomology spaces and the standard Tractor bundle $\mc{T}$. Several of these geometries are then explored in more detail, and th

J. F. Cariñena, J. de Lucas

The geometric theory of Lie systems is used to establish integrability conditions for several systems of differential equations, in particular some Riccati equations and Ermakov systems. Many different integrability criteria in the literature will be analysed from this new perspective, and some applications in physics will be given.

Colin Bailey, Joseph Oliveira

We discuss the group of automorphisms of a general MR-algebra. We develop several functors between implication algebras and cubic algebras. These allow us to generalize the notion of inner automorphism. We then show that this group is always isomorphic to the group of inner automorphisms of a filter algebra.

Stuart Armstrong

This paper analyses non-regular $|2|$-graded geometries, and show that they share many of the properties of regular geometries -- the existence of a unique normal Cartan connection encoding the structure, the harmonic curvature as obstruction to flatness of the geometry, the existence of the first two BGG splitting operators and of (in most cases) invariant

B. Sathiapalan

A gauge invariant action for the open bosonic string has been proposed in an earlier paper. We work out the consequences of this proposal for the lowest mode, viz. the tachyon. The action can be calculated for generic momenta, perturbatively, order by order in the tachyon field. For on shell tachyons we explicitly calculate the cubic action and show that it

Ken Sekimoto

The internal (or residual) stress is among the key notions to describe the state of the systems far from equilibrium. Such stress is invisible on the macroscopic scale where the system is regarded as a blackbox. Yet nonequilibrium macroscopic operations allow to create and observe the internal stress. We present in this lecture some examples of the internal

The OPAL Collaboration, G. Abbiendi

Hadronic final states with a hard isolated photon are studied using data taken at centre-of-mass energies around the mass of the Z0 boson with the OPAL detector at LEP. The strong coupling alpha S is extracted by comparing data and QCD predictions for event shape observables at average reduced centre-of-mass energies ranging from 24 GeV to 78 GeV, and the en

Tanja Bode, Pablo Laguna, Deirdre M. Shoemaker, Ian Hinder

Approximate solutions to the Einstein field equations are a valuable tool to investigate gravitational phenomena. An important aspect of any approximation is to investigate and quantify its regime of validity. We present a study that evaluates the effects that approximate puncture initial data, based on &#34;skeleton&#34; solutions to the Einstein constraint

Mario Gaspero

A narrow peak in the pi+ pi- mass distribution was seen by the Rome-Syracuse Collaboration in bar-p n --> 2 pi+ 3 pi- annihilation at rest 39 years ago. The reanalysis of this peak finds a mass of 757.4 +- 2.6 MeV/c^2 and a width slightly narrower than the experimental resolution. The evidence of the peak is 5.2 standard deviations. This state is generated i

Alexander Tovbis, Stephanos Venakides

The initial value problem of an integrable system, such as the Nonlinear Schr\&#34; odinger equation, is solved by subjecting the linear eigenvalue problem arising from its Lax pair to inverse scattering, and, thus, transforming it to a matrix Riemann-Hilbert problem (RHP) in the spectral variable. In the semiclassical limit, the method of nonlinear steepest

Anzor Khelashvili, Tamar Khachidze

The additional hidden symmetry of the Coulomb-Kepler problem is reviewed in classical as well as in quantum mechanics. The main purpose is to elucidate the role of this kind of symmetries in the reduction of physical problems, to show algebraic possibilities of derivation of spectra. The original results are presented also. They are hidden symmetries in the

Ruo-Wei Hung, Chih-Chia Yao

Let $G=(V,E)$ be a graph without isolated vertices. A matching in $G$ is a set of independent edges in $G$. A perfect matching $M$ in $G$ is a matching such that every vertex of $G$ is incident to an edge of $M$. A set $S\subseteq V$ is a \textit{paired-dominating set} of $G$ if every vertex in $V-S$ is adjacent to some vertex in $S$ and if the subgraph $G[S

Paul Monsky

We give a treatment of the Brenner-Monsky example based on polynomial algebra and linear algebra. No prior knowledge of tight closure theory, Hilbert-Kunz theory, algebraic geometry or local cohomology is assumed.

Roberto Martinez-Villa, Øyvind Solberg

Motivated by constructions in the representation theory of finite dimensional algebras we generalize the notion of Artin-Schelter regular algebras of dimension $n$ to algebras and categories to include Auslander algebras and a graded analogue for infinite representation type. A generalized Artin-Schelter regular algebra or a category of dimension $n$ is show

O. Godet, P. Sizun, D. Barret, P. Mandrou

For several decades now, wide-field coded mask cameras have been used with success to localise Gamma-ray bursts (GRBs). In these instruments, the event count rate is dominated by the photon background due to their large field of view and large effective area. It is therefore essential to estimate the instrument background expected in orbit during the early p

Jakub Zakrzewski, Dominique Delande

Realistic simulations of current ultra-cold atoms experiments in optical lattices show that the ramping up of the optical lattice is significantly nonadiabatic, implying that experimentally prepared Mott insulators are not really in the ground state of the atomic system. The nonadiabaticity is even larger in the presence of a secondary quasi-periodic lattice

Alexander Drewitz, Alejandro F. Ramírez

Recently Simenhaus proved that for any elliptic random walk in random environment, transience in the neighborhood of a given direction is equivalent to the a.s. existence of a deterministic asymptotic direction and to transience in any direction in the open half space defined by this asymptotic direction. Here we prove an improved version of this result and

Markus M. Geipel, Claudio J. Tessone, Frank Schweitzer

Trees are a special sub-class of networks with unique properties, such as the level distribution which has often been overlooked. We analyse a general tree growth model proposed by Klemm {\em et. al.} (2005) to explain the growth of user-generated directory structures in computers. The model has a single parameter $q$ which interpolates between preferential

M. Ignaccolo, M. Latka, W. Jernajczyk, P. Grigolini

EEG time series are analyzed using the diffusion entropy method. The resulting EEG entropy manifests short-time scaling, asymptotic saturation and an attenuated alpha-rhythm modulation. These properties are faithfully modeled by a phenomenological Langevin equation interpreted within a neural network context. Detrended fluctuation analysis of the EEG data is

D. V. Fedorov, A. S. Jensen, M. Thøgersen

We investigate the possibility of calculating the parameters of few-body resonances using the oscillator trap boundary conditions. We place the few-body system in an oscillator trap and calculate the energy spectrum and the strength function of a suitably chosen transition. Broader resonances are identified as Lorentzian peaks in the strength function. Narro

H. Alloul, I. R. Mukhamedshin, T. A. Platova, A. V. Dooglav

We report $^{23}$Na and $^{59}$Co nuclear magnetic (NMR) and quadrupolar resonance (NQR) studies for the $x=2/3$ phase of the lamellar oxide Na$_{x}$CoO$_{2}$, which allowed us to establish reliably the atomic order of the Na layers and their stacking between the CoO$_{2}$ slabs. We evidence that the Na$^{+}$ order stabilizes filled non magnetic Co$^{3+}$ io

Petra Schwer

In the present thesis geometric properties of non-discrete affine buildings are studied. We cover in particular affine $Λ$-buildings, which were introduced by Curtis Bennett in 1990 and which already have proven to be useful for applications. The main results are as follow: First we prove an extension theorem for ecological isomorphisms of buildings at infin

Hadi Rahmani, William C. Saslaw, Saeed Tavasoli

This is the first exploration of the galaxy distribution function at redshifts greater than about 0.1. Redshifts are based on the North and South GOODS Catalogs. In each catalog we examine clustering in the two redshift bands 0.47 < z < 0.8 and 0.9 < z < 1.5. The mean redshifts of the samples in these bands are about 0.6 and 1.1. Our main result is that at t

Andrey M Pupasov, Boris F Samsonov, Jean-Marc Sparenberg

Spectral properties of a coupled $N \times N$ potential model obtained with the help of a single non-conservative supersymmetric (SUSY) transformation starting from a system of $N$ radial Schrödinger equations with the zero potential and finite threshold differences between the channels are studied. The structure of the system of polynomial equations which d

R. van Boekel, M. Guedel, Th. Henning, F. Lahuis

(Note: this is a shortened version of the original &#34;structured&#34; (A&A format) abstract.) The 12.81 micrometer [NeII] line has recently gained interest as a potential tracer of gas in the tenuous surface layers of circumstellar disks. The line has been detected using the Spitzer Space Telescope in many young stars, yet these observations neiter spatial

Erik Lötstedt, Ulrich D. Jentschura

In the relativistic and the nonrelativistic theoretical treatment of moderate and high-power laser-matter interaction, the generalized Bessel function occurs naturally when a Schrödinger-Volkov and Dirac-Volkov solution is expanded into plane waves. For the evaluation of cross sections of quantum electrodynamic processes in a linearly polarized laser field,

Rich Bielby, T. Shanks, U. Sawangwit, S. M. Croom

We investigate the use of simple colour cuts applied to the SDSS optical imaging to perform photometric selections of emission line galaxies out to z<1. From colour-cuts using the SDSS g, r and i bands, we obtain mean photometric redshifts of z=0.32+-0.08, z=0.44+-0.12 and z=0.65+-0.21. We further calibrate our high redshift selection using spectroscopic obs

J. S. Kaastra, C. P. de Vries, E. Costantini, J. W. A. den Herder

The Crab nebula and pulsar have been widely used as a calibration source for X-ray instruments. The in-flight effective area calibration of the Reflection Grating Spectrometers (RGS) of XMM-Newton depend upon the availability of reliable calibration sources. We investigate how the absolute effective area calibration of RGS can be obtained using Crab as a sta

Sanli Faez, P. M. Johnson, D. A. Mazurenko, Ad Lagendijk

We have experimentally measured the distribution of the second-harmonic intensity that is generated inside a highly-scattering slab of porous gallium phosphide. Two complementary techniques for determining the distribution are used. First, the spatial distribution of second-harmonic light intensity at the side of a cleaved slab has been recorded. Second, the

A. Tziamtzis, M. Schirmer, P. Lundqvist, J. Sollerman

We searched for a fast moving H$α$ shell around the Crab nebula. Such a shell could account for this supernova remnant&#39;s missing mass, and carry enough kinetic energy to make SN 1054 a normal Type II event. Deep H$α$ images were obtained with WFI at the 2.2m MPG/ESO telescope and with MOSCA at the 2.56m NOT. The data are compared with theoretical expecta

V. A. Galaktionov

It is shown that self-similar blow-up for a fourth-order reaction-diffusion equation is incomplete in the sense that, in general, there exists a self-similar extension of solutions after blow-up. Other types of complete blow-up of non self-similar form are discussed.

LAT Collaboration, W. B. Atwood

(Abridged) The Large Area Telescope (Fermi/LAT, hereafter LAT), the primary instrument on the Fermi Gamma-ray Space Telescope (Fermi) mission, is an imaging, wide field-of-view, high-energy gamma-ray telescope, covering the energy range from below 20 MeV to more than 300 GeV. This paper describes the LAT, its pre-flight expected performance, and summarizes t

Remo Garattini

The cosmological constant induced by quantum fluctuation of the graviton on a given background is considered as a tool for building a spectrum of different geometries. In particular, we apply the method to the Schwarzschild background with positive and negative mass parameter. In this way, we put on the same level of comparison the related naked singularity

Dirk Johrendt, Rainer Poettgen

BaFe2As2 is the parent compound of the &#39;122&#39; iron arsenide superconductors and crystallizes with the tetragonal ThCr2Si2 type structure, space group I4/mmm. A spin density wave transition at 140 K is accompanied by a symmetry reduction to space group Fmmm and simultaneously by antiferromagnetic ordering. Hole-doping induces superconductivity in Ba1-x

Raimond Snellings

Anisotropic flow is recognized as one of the main observables providing information on the early dynamics in heavy-ion collisions. The large elliptic flow observed at RHIC is considered to be evidence for almost perfect liquid behavior of the strongly coupled Quark Gluon Plasma produced in the collisions. In this report we review our current understanding of

W. Gloeckle, M. Schwamb

An exact inversion formula for the Lorentz integral transform (LIT) is provided together with the spectrum of the LIT kernel. The exponential increase of the inverse Fourier transform of the LIT kernel entering the inversion formula explains the ill-posed character of the LIT approach. Also the continuous spectrum of the LIT kernel, which approaches zero poi

Baptiste Jeudy, Christine Largeron, François Jacquenet

Data mining algorithms are now able to efficiently deal with huge amount of data. Various kinds of patterns may be discovered and may have some great impact on the general development of knowledge. In many domains, end users may want to have their data mined by data mining tools in order to extract patterns that could impact their business. Nevertheless, tho

V. S. Olkhovsky, M. E. Dolinska

In practically all known till now methods of nuclear chronometry there were usually taken into account the life-times of only fundamental states of $α$-radioactive nuclei. But in the processes of nuclear synthesis in stars and under the influence of the constant cosmic radiation on surfaces of planets the excitations of the $α$-radioactive nuclei are going o

Krzysztof Byczuk, Michael Sekania, Walter Hofstetter, Arno P. Kampf

Paramagnetic solutions of the ionic Hubbard model at half-filling in dimensions $D>2$ indicate that the band and the Mott insulator phases are separated by a metallic phase. We present zero-temperature dynamical mean-field theory solutions, which include antiferromagnetic long-range order, and show that the one-particle spectral functions always possess an e

Michael Braverman

We give conditions under which the tail probability of the supremum over unit interval of a Levy process with light tail is equivalent to the tail of the value of the process at the right endpoint.

P. Dimopoulos, H. Simma, A. Vladikas

We apply an Osterwalder-Seiler version of twisted mass QCD to a study of the $B_K$ parameter, in which three of the four quark fields making up the relevant $ΔS =2$ operator are maximally twisted with the same twist angle, while the fourth one has a twist angle of opposite sign. It is known that this setup ensures automatic improvement of the bare $K^0$-$\ov

Nestor Sanchez, Emilio J. Alfaro

The analysis of the distribution of stars in open clusters may yield important information on the star formation process and early dynamical evolution of stellar clusters. Here we address this issue by systematically characterizing the internal spatial structure of 16 open clusters in the Milky Way spanning a wide range of ages. Cluster stars have been selec

F. Vagnetti, K. Boutsia, D. Trevese

Low Luminosity Active Galactic Nuclei (LLAGNs) are contaminated by the light of their host galaxies, thus they cannot be detected by the usual colour techniques. For this reason their evolution in cosmic time is poorly known. Variability is a property shared by virtually all active galactic nuclei, and it was adopted as a criterion to select them using multi

I. Pallecchi, C. Fanciulli, M. Tropeano, A. Palenzona

We measure magnetotransport of F doped SmFeAsO samples up to 28T and we extract the upper critical fields, using different criteria. In order to circumvent the problem of criterion-dependence Hc2 values, we suggest a thermodynamic estimation of the upper critical field slope dHc2/dT based on the analysis of conductivity fluctuations in the critical regime. A

Krzysztof Barański, Bogusława Karpińska, Anna Zdunik

We prove that the boundary of a component $U$ of the basin of an attracting periodic cycle (of period greater than 1) for an exponential map on the complex plane has Hausdorff dimension greater than 1 and less than 2. Moreover, the set of points in the boundary of $U$ which do not escape to infinity has Hausdorff dimension (in fact: hyperbolic dimension) gre

M. C. Cushing, D. Looper, A. J. Burgasser, J. D. Kirkpatrick

We present the serendipitous discovery of an L subdwarf, 2MASS J06164006-6407194, in a search of the Two Micron All Sky Survey for T dwarfs. Its spectrum exhibits features indicative of both a cool and metal poor atmosphere including a heavily pressured-broadened K I resonant doublet, Cs I and Rb I lines, molecular bands of CaH, TiO, CrH, FeH, and H2O, and e

Arno B. J. Kuijlaars

Multiple orthogonal polynomials are traditionally studied because of their connections to number theory and approximation theory. In recent years they were found to be connected to certain models in random matrix theory. In this paper we introduce the notion of a multiple orthogonal polynomial ensemble (MOP ensemble) and derive some of their basic properties

L. Tincani, R. M. Noack, D. Baeriswyl

We investigate the neutral-to-ionic insulator-insulator transition in one-dimensional materials by treating a strong-coupling effective model based on the ionic Hubbard model using the density-matrix renormalization group and finite-size scaling. The effective model, formulated in a spin-one representation, contains a single parameter. We carry out an extens

A. P. Serebrov

The range of nucleon interaction 10-4 cm - 1 cm is interesting because it corresponds to the mass range of a intermediate particle inside so named &#34;axion window&#34; that is not closed yet by experiment. Depolarization of ultracold neutrons (UCN) during their storage in material traps can be caused by CP-violating pseudo-magnetic precession of the neutro

J. D. Vergados, F. T. Avignone, I. Giomataris

The coherent contribution of all neutrons in neutrino nucleus scattering due to the neutral current is examined considering the Spallation Neutron Source (SNS) as a source of neutrinos. SNS is a prolific pulsed source of electron and muon neutrinos as well as muon antineutrinos.

Yogesh M. Joshi

A scaling model is developed to correlate relaxation time distribution of soft glassy materials to ultimate recovery. We propose that in the limit of creep-recovery time smaller than age, time translational invariance can be applied to ageing soft materials. In such limit, multimode linear viscoelastic model with Spriggs relaxation spectrum predicts enhancem

C. Martelli, A. De Martino, E. Marinari, M. Marsili

Understanding the organization of reaction fluxes in cellular metabolism from the stoichiometry and the topology of the underlying biochemical network is a central issue in systems biology. In this task, it is important to devise reasonable approximation schemes that rely on the stoichiometric data only, because full-scale kinetic approaches are computationa

Dao-Jun Liu, Ying-Li Zhang, Xin-Zhou Li

We generalize the field theory of global monopole to Dirac-Born-Infeld(DBI) field and investigate the gravitational property of a DBI global monopole in four-dimensional spherically symmetric spacetime. The coupled equations for the metric and the DBI scalar field are solved asymptotically and numerically. It is found that, just as a canonical global monopol

A. I. Levon, G. Graw, Y. Eisermann, R. Hertenberger

The excitation spectra in the deformed nucleus 230Th were studied by means of the (p,t) reaction, using the Q3D spectrograph facility at the Munich Tandem accelerator. The angular distributions of tritons are measured for about 200 excitations seen in the triton spectra up to 3.3 MeV. Firm 0+ assignments are made for 16 excited states by comparison of experi

J. V. Perea-Calderon, D. A. Garcia-Hernandez, P. Garcia-Lario, R. Szczerba

We investigate the dual-dust chemistry (DDC) phenomenon in PNe and discuss reasons for its occurrence, by analyzing Spitzer/IRS spectra of a sample of 40 Galactic PNe among which 26 belong to the Galactic Bulge (GB). The mixed chemistry is derived from the simultaneous detection of PAH features in the 6-14 micron range and crystalline silicates (CS) beyond 2

Frédérique Bassino, Julien David, Cyril Nicaud

We prove that, for any arbitrary finite alphabet and for the uniform distribution over deterministic and accessible automata with n states, the average complexity of Moore&#39;s state minimization algorithm is in O(n log n). Moreover this bound is tight in the case of unary utomata.

Nicolas Bousquet, Jean Daligault, Stephan Thomasse, Anders Yeo

The MULTICUT IN TREES problem consists in deciding, given a tree, a set of requests (i.e. paths in the tree) and an integer k, whether there exists a set of k edges cutting all the requests. This problem was shown to be FPT by Guo and Niedermeyer. They also provided an exponential kernel. They asked whether this problem has a polynomial kernel. This question

A. Brunthaler, P. Castangia, A. Tarchi, C. Henkel

We present high-resolution spectral line and continuum VLBI and VLA observations of the nuclear region of NGC 253 at 22 GHz. While the water vapor masers in this region were detected on arcsecond and milliarcsecond scales, we could not detect any compact continuum emission with a 5 sigma upper limit of ~ 1 mJy. The observations reveal that the water maser em

Mikolaj Bojanczyk

A new class of languages of infinite words is introduced, called the max-regular languages, extending the class of $ω$-regular languages. The class has two equivalent descriptions: in terms of automata (a type of deterministic counter automaton), and in terms of logic (weak monadic second-order logic with a bounding quantifier). Effective translations betwee

Laurent Bienvenu, Rod Downey

Solovay proved that there exists a computable upper bound f of the prefix-free Kolmogorov complexity function K such that f (x) = K(x) for infinitely many x. In this paper, we consider the class of computable functions f such that K(x) <= f (x)+O(1) for all x and f (x) <= K(x) + O(1) for infinitely many x, which we call Solovay functions. We show that Solova

Floor van Leeuwen

A new reduction of the astrometric data as produced by the Hipparcos mission has been published, claiming that the accuracies for nearly all stars brighter than magnitude $\mathrm{Hp}=8$ are improved, by up to a factor 4, compared to the original catalogue. As correlations between the underlying abscissa residuals have also been reduced by more than an order

Jérémy Barbay, Gonzalo Navarro

We explore various techniques to compress a permutation $π$ over n integers, taking advantage of ordered subsequences in $π$, while supporting its application $π$(i) and the application of its inverse $π^{-1}(i)$ in small time. Our compression schemes yield several interesting byproducts, in many cases matching, improving or extending the best existing resul

Rupa Chatterjee, Dinesh K. Srivastava, Sangyong Jeon

We present a reanalysis of single photon production from relativistic collision of lead nuclei at CERN SPS measured by the WA98 experiment. The refinements include use of iso-spin and shadowing corrected NLO pQCD treatment for prompt photon production using an optimized scale for factorization, renormalization, and fragmentation and use of hydrodynamics suit

Jean Reignier

I propose an alternative, purely kinematical, derivation of Einstein&#39;s Doppler formula. It is valid for periodic signals of any shape that propagate with the velocity of light. The formula is asymptotic in a parameter proportional to the relative variation of the distance source-receiver during one period. As a by-product, I also derive an alternative pr

Sylvain Raybaud, Caroline Lavecchia, David Langlois, Kamel Smaïli

A confidence measure is able to estimate the reliability of an hypothesis provided by a machine translation system. The problem of confidence measure can be seen as a process of testing : we want to decide whether the most probable sequence of words provided by the machine translation system is correct or not. In the following we describe several original wo

Sonnet Q H Nguyen, Lukasz A Turski

In this article, we prove that Dirac brackets for Hamiltonian and non-Hamiltonian constrained systems can be derived recursively. We then study the applicability of that formulation in analysis of some interesting physical models. Particular attention is paid to the feasibility of implementation code for Dirac brackets in Computer Algebra System and analytic

Alexandre Masquelein, Anne Quéguiner-Mathieu, Jean-Pierre Tignol

Izhboldin and Karpenko proved in 2000 that any quadratic form of dimension 8 with trivial discriminant and Clifford algebra of index 4 is isometric to the transfer, with respect to some quadratic étale extension, of a quadratic form similar to a 2-fold Pfister form. We give a new proof of this result, based on a theorem of decomposability for degree 8 and in

G. Boue, J. Laskar

We consider the solid-solid interactions in the two body problem. The relative equilibria have been previously studied analytically and general motions were numerically analyzed using some expansion of the gravitational potential up to the second order, but only when there are no direct interactions between the orientation of the bodies. Here we expand the p

F. Buisseret

Modeling glueballs as bound states of transverse constituent gluons allows to understand the main features of the lattice QCD glueball spectrum. In particular it has been shown in previous works that the lightest C-even glueballs can be seen as bound states of two transverse constituent gluons interacting via a funnel potential. In the present study we show

Gregory Schehr, Satya N. Majumdar

We introduce a family of real random polynomials of degree n whose coefficients a_k are symmetric independent Gaussian variables with variance <a_k^2> = e^{-k^α}, indexed by a real α\geq 0. We compute exactly the mean number of real roots <N_n> for large n. As αis varied, one finds three different phases. First, for 0 \leq α< 1, one finds that <N_n> \sim (\f

J. Wang, J. Y. Wei, P. F. Xiao

The nature of Low-ionization Nuclear Emission-line Regions (LINERs) has been an open question for a long time. We study the properties of LINERs from several different aspects. The LINERs are found to consist of two different categories that can be clearly separated in the traditional BPT diagrams, especially in the [OI]/Ha vs. [OIII]/Hb diagram. LINERs with

Takeo Kojima

We construct a free field realization of the elliptic quantum algebra $U_{q,p}(\hat{sl_N})$ for arbitrary level $k \neq 0,-N$. We study Drinfeld current and the screening current associated with $U_{q,p}(\hat{sl_N})$ for arbitrary level $k$. In the limit $p \to 0$ this realization becomes $q$-Wakimoto realization for $U_q(\hat{sl_N})$.

Wen-Long Lu, Zhi-Guo Wang, Shi-Jian Gu, Hai-Qing Lin

In this paper, we study the role of both &#34;spin&#34;(species) and mass imbalance in a mixture of two species of fermionic atoms with attractive interaction in an one-dimensional optical lattice. Using the bosonization approach, quantum phase transitions between a liquid phase and phase separated states are studied under various conditions of interaction,

T. Kojima, J. Shiraishi

We review the free field realization of the deformed Virasoro algebra $Vir_{q,t}$ and the deformed $W$ algebra $W_{q,t}(\hat{gl_N})$. We explicitly construct two classes of infinitly many commutative operators ${\cal I}_m$, ${\cal G}_m$, $(m \in {\mathbb N})$, in terms of these algebras. They can be regarded as the elliptic deformation of the local and nonlo

Midori Tokutani, Naoki Yoshida, S. Peng Oh, Naoshi Sugiyama

We calculate the spin temperature and 21 cm brightness of early \HII regions around the first stars. We use outputs from cosmological radiation-hydrodynamics simulations of the formation and evolution of early \HII regions. In the pre-reionization era, \HII regions around massive primordial stars have diameters of a few kpc. The gas within the \HII regions i

D. McKay, M. White, B. DeMarco

We measure the temperature of ultra-cold Rb-87 gases transferred into an optical lattice and compare to non-interacting thermodynamics for a combined lattice--parabolic potential. Absolute temperature is determined at low temperature by fitting quasimomentum distributions obtained using bandmapping, i.e., turning off the lattice potential slowly compared wit

A. A. Ivanov, S. P. Knurenko, I. Ye. Sleptsov

The energy spectrum of cosmic rays in the range 10^15 eV to 6*10^19 eV has been studied using the air Cherenkov light detectors of the Yakutsk array. The total flux of photons produced by relativistic electrons (including positrons as well, hereafter) of extensive air showers in the atmosphere is used as the energy estimator of the primary particle initiatin

Yutaka Yoshida

We study the virtual photon structure functions from gauge/string duality. If the Bjorken variable x is not small, supergravity approximation becomes good in dual string theory. We calculate the virtual photon structure functions at large &#39;t Hooft coupling in a moderate x-region and determine x-behavior of the structure functions. We also show that the C

J. Fu, J. L. Hou, J. Yin, R. X. Chang

Based on a simple model of the chemical evolution of the Milky Way disk, we investigate the disk oxygen abundance gradient and its time evolution. Two star formation rates (SFRs) are considered, one is the classical Kennicutt-Schmidt law ($ Ψ= 0.25 Σ_{\rm{gas}}^{1.4}$, hereafter C-KS law), another is the modified Kennicutt law ($Ψ= αΣ_{\rm{gas}}^{1.4} ({V/r}

Akira Imada, Tatsuki Yasuda, Toshihiro Omodaka, Shota Oizumi

We present time-resolved CCD photometry of a dwarf nova NSV 4838 (UMa 8, SDSS J102320.27+440509.8) during the 2005 June and 2007 February outburst. Both light curves showed superhumps with a mean period of 0.0699(1) days for the 2005 outburst and 0.069824(83) days for the 2007 outburst, respectively. Using its known orbital period of 0.0678 days, we estimate