November 2007 arXiv papers — page 8

M. Diehl, Th. Feldmann, P. Kroll

We discuss the phenomenology of strange-quark dynamics in the nucleon, based on experimental and theoretical results for electroweak form factors and for parton densities. In particular, we construct a model for the generalized parton distribution that relates the asymmetry s(x)-sbar(x) between the longitudinal momentum distributions of strange quarks and an

Fabio Zucca

A classical inequality, which is known for families of monotone functions, is generalized to a larger class of families of measurable functions. Moreover we characterize all the families of functions for which the equality holds. We apply this result to a problem arising from probability theory.

Christopher Gordon, Kate Land, Anze Slosar

We estimate the solar system motion relative to the cosmic microwave background using type Ia supernovae (SNe) measurements. We take into account the correlations in the error bars of the SNe measurements arising from correlated peculiar velocities. Without accounting for correlations in the peculiar velocities, the SNe data we use appear to detect the pecul

E. G. van Putten, I. M. Vellekoop, A. P. Mosk

We present a method for full spatial phase and amplitude control of a laser beam using a twisted nematic liquid crystal display combined with a spatial filter. By spatial filtering we combine four neighboring pixels into one superpixel. At each superpixel we are able to independently modulate the phase and the amplitude of light. We demonstrate experimentall

Alexander A. Andrianov, Francesco Cannata, Alexander Y. Kamenshchik, Daniele Regoli

We study the procedure of the reconstruction of phantom-scalar field potentials in two-field cosmological models. It is shown that while in the one-field case the chosen cosmological evolution defines uniquely the form of the scalar potential, in the two-field case one has an infinite number of possibilities. The classification of a large class of possible p

Avatar Tulsi

The search problem is to find a state satisfying certain properties out of a given set. Grover's algorithm drives a quantum computer from a prepared initial state to the target state and solves the problem quadratically faster than a classical computer. The algorithm uses selective transformations to distinguish the initial state and target state from ot

A. Damineli, D. J. Hillier, M. F. Corcoran, O. Stahl

A full description of the 5.5-yr low excitation events in Eta Carinae is presented. We show that they are not as simple and brief as previously thought, but a combination of two components. The first, the 'slow variation' component, is revealed by slow changes in the ionization level of circumstellar matter across the whole cycle and is caused by gra

L. Demkó, I. Kézsmárki, G. Mihály, N. Takeshita

We have studied the bandwidth-temperature-magnetic field phase diagram of RE(0.55)Sr(0.45)MnO(3) colossal magnetoresistance manganites with ferromagnetic metallic (FM) ground state. The bandwidth (or equivalently the double exchange interaction) was controlled both via chemical substitution and hydrostatic pressure with a focus on the vicinity of the critica

Junegone Chay

Transverse-momentum-dependent parton distribution functions are analyzed in semi-inclusive deep inelastic scattering at low transverse momentum using soft-collinear effective theory. The transverse-momentum-dependent parton distribution functions are defined on the lightcone without distorting the lightcone path nor adding additional soft Wilson lines. In th

P. P. Avelino, L. M. G. beça, C. J. A. P. Martins

We revisit the paradigm of unified dark energy discussing in detail the averaging problem in this type of scenarios, highlighting the need for a full non-linear treatment. We also address the question of if and how models with one or several dark fluids can be observationally distinguished. Simpler and physically clearer derivations of some key results, most

HADES Collaboration, G. Agakishiev, C. Agodi, H. Alvarez Pol

The emission of e+e- pairs from C+C collisions at an incident energy of 1 GeV per nucleon has been investigated. The measured production probabilities, spanning from the pi0-Dalitz to the rho/omega! invariant-mass region, display a strong excess above the cocktail of standard hadronic sources. The bombarding-energy dependence of this excess is found to scale

D. Le Bolloc'h, V. L. R. Jacques, N. Kirova, J. Dumas

High-resolution coherent x-ray diffraction experiment has been performed on the charge density wave (CDW) system K$_{0.3}$MoO$_3$. The $2k_F$ satellite reflection associated with the CDW has been measured with respect to external dc currents. In the sliding regime, the $2k_F$ satellite reflection displays secondary satellites along the chain axis which corre

Paolo Facchi, Giuseppe Marmo, Saverio Pascazio

A quantum Zeno dynamics can be obtained by means of frequent measurements, frequent unitary kicks or a strong continuous coupling and yields a partition of the total Hilbert space into quantum Zeno subspaces, among which any transition is hindered. We focus on the "continuous" version of the quantum Zeno effect and look at several interesting example

Pier Stefano Corasaniti, Alessandro Melchiorri

WMAP observations have accurately determined the position of the first two peaks and dips in the CMB temperature power spectrum. These encode information on the ratio of the distance to the last scattering surface to the sound horizon at decoupling. However pre-recombination processes can contaminate this distance information. In order to assess the amplitud

George E. A. Matsas, Vicente Pleitez, Alberto Saa, Daniel A. T. Vanzella

We revisit, qualify, and objectively resolve the seemingly controversial question about what is the number of dimensional fundamental constants in Nature. For this purpose, we only assume that all we can directly measure are space and time intervals, and that this is enough to evaluate any physical observable. We conclude that the number of dimensional funda

Victoria Mazo, Jacob Sonnenschein

We analyze the thermal phases of a non critical holographic model of QCD. The model is based on a six dimensional background of $N_c$ non extremal D4 branes wrapping a spacial circle of radius $R$ and the compactified Euclidean time direction of radius $β=1/T$. We place in this background stacks of $N_f$ D4 and anti-D4 flavor probe branes with a separation d

R. Koc, O. Ozer, H. Tutunculer, R. G. Yildirim

We consider solutions of the $2\times 2$ matrix Hamiltonian of physical systems within the context of the asymptotic iteration method. Our technique is based on transformation of the associated Hamiltonian in the form of the first order coupled differential equations. We construct a general matrix Hamiltonian which includes a wide class of physical models. T

T. Anguita, R. W. Schmidt, E. L. Turner, J. Wambsganss

We use the high magnification event seen in the 1999 OGLE campaign light curve of image C of the quadruply imaged gravitational lens Q2237+0305 to study the structure of the quasar engine. We have obtained g'- and r'-band photometry at the Apache Point Observatory 3.5m telescope where we find that the event has a smaller amplitude in the r'-band than in the

Arjeh M. Cohen, Gabor Ivanyos, Dan A. Roozemond

Let L be a simple finite-dimensional Lie algebra of characteristic distinct from 2 and from 3. Suppose that L contains an extremal element that is not a sandwich, that is, an element x such that [x, [x, L]] is equal to the linear span of x in L. In this paper we prove that, with a single exception, L is generated by extremal elements. The result is known, at

Linda Ostman, Ariel Goobar, Edvard Mortsell

Context. Observations of quasars shining through foreground galaxies, offer a way to probe the dust extinction curves of distant galaxies. Interesting objects for this study are found in strong gravitational lensing systems, where the foreground galaxies generate multiple images. Aims. The reddening law of lensing galaxies is investigated by studying the col

N. Bartolo, S. Matarrese, M. Pietroni, A. Riotto

Inflationary observables, like the power spectrum, computed at one- and higher-order loop level seem to be plagued by large infra-red corrections. In this short note, we point out that these large infra-red corrections appear only in quantities which are not directly observable. This is in agreement with general expectations concerning infra-red effects.

Daniel Grumiller

The semi-classical approximation to black hole partition functions is not well-defined, because the classical action is unbounded and the first variation of the uncorrected action does not vanish for all variations preserving the boundary conditions. Both problems can be solved by adding a Hamilton-Jacobi counterterm. I show that the same problem and solutio

YongYao Li, HuaRong Zhang, YongZhu Chen, JianYing Zhou

The coherent superposition of two-atomic levels induced by coherent population trapping is employed in a standard $Λ$ type scheme to form a tripod-like system. A weak probe pulse scanning across the system is shown to experience a crossover from absorption to transparent and then to amplification. Consequently the group velocity of the probe pulse can be con

R. Hoehmann, U. Kuhl, H. -J. Stoeckmann

From a reflection measurement in a rectangular microwave billiard with randomly distributed scatterers the scattering and the ordinary fidelity was studied. The position of one of the scatterers is the perturbation parameter. Such perturbations can be considered as {\em local} since wave functions are influenced only locally, in contrast to, e. g., the situa

Jochen Keller, Ralf Hofmann, Francesco Giacosa

We compute the two-point correlation of the energy density for the massless mode in deconfining SU(2) Yang-Mills thermodynamics and point towards a possible application for the physics of cold, dilute, and stable clouds of atomic hydrogen within the Milky Way.

André Chailloux, Iordanis Kerenidis

We study the role of help in Non-Interactive Zero-Knowledge protocols and its relation to the standard interactive model. In the classical case, we show that help and interaction are equivalent, answering an open question of Ben-Or and Gutfreund. This implies a new complete problem for the class SZK, the Image Intersection Density. For this problem, we also

Gianni Pagnini, Francesco Mainardi

The spectrum profile that emerges in molecular spectroscopy and atmospheric radiative transfer as the combined effect of Doppler and pressure broadenings is known as the Voigt profile function. Because of its convolution integral representation, the Voigt profile can be interpreted as the probability density function of the sum of two independent random vari

Archana Bora, Ranjan Gupta, Harinder P. Singh, Jayant Murthy

In order to develop a pipeline for automated classification of stars to be observed by the TAUVEX ultraviolet space Telescope, we employ an artificial neural network (ANN) technique for classifying stars by using synthetic spectra in the UV region from 1250Åto 3220Åas the training set and International Ultraviolet Explorer (IUE) low resolution spectra as the

Ayman Kachmar

This paper is devoted to an analysis of vortex-nucleation for a Ginzburg-Landau functional with discontinuous constraint. This functional has been proposed as a model for vortex-pinning, and usually accounts for the energy resulting from the interface of two superconductors. The critical applied magnetic field for vortex nucleation is estimated in the London

Pavel Exner, Andrea Mantile

We investigate relations between spectral properties of a single-centre point-interaction Hamiltonian describing a particle confined to a bounded domain $\Omega\subset\mathbb{R}^{d},\: d=2,3$, with Dirichlet boundary, and the geometry of $\Omega$. For this class of operators Krein's formula yields an explicit representation of the resolvent in terms of the i

V. Gorini, A. Y. Kamenshchik, U. Moschella, O. F. Piattella

We exploit the gauge-invariant formalism to analyse the perturbative behaviour of two cosmological models based on the generalized Chaplygin gas describing both dark matter and dark energy in the present Universe. In the first model we consider the generalized Chaplygin gas alone, while in the second one we add a baryon component to it. We extend our analysi

E. Di Gennaro, D. Morello, C. Miletto, S. Savo

We present a study of the lensing properties of two-dimensional (2-D) photonic quasicrystal (PQC) slabs made of dielectric cylinders arranged according to a 12-fold-symmetric square-triangle aperiodic tiling. Our full-wave numerical analysis confirms the results recently emerged in the technical literature and, in particular, the possibility of achieving foc

G. Arzhantseva, M. R. Bridson, T. Januszkiewicz, I. J. Leary

We construct finitely generated groups with strong fixed point properties. Let $\mathcal{X}_{ac}$ be the class of Hausdorff spaces of finite covering dimension which are mod-$p$ acyclic for at least one prime $p$. We produce the first examples of infinite finitely generated groups $Q$ with the property that for any action of $Q$ on any $X\in \mathcal{X}_{ac}

Henning Bostelmann, Claudio D'Antoni, Gerardo Morsella

We present a method of short-distance analysis in quantum field theory that does not require choosing a renormalization prescription a priori. We set out from a local net of algebras with associated pointlike quantum fields. The net has a naturally defined scaling limit in the sense of Buchholz and Verch; we investigate the effect of this limit on the pointl

Takaaki Ishii, Goro Ishiki, Kazutoshi Ohta, Shinji Shimasaki

Chern-Simons theory on a U(1) bundle over a Riemann surface Σ_g of genus g is dimensionally reduced to BF theory with a mass term, which is equivalent to the two-dimensional Yang-Mills on Σ_g. We show that the former is inversely obtained from the latter by the extended matrix T-duality developed in hep-th/0703021. For the case of g=0 (i.e. S^2), the U(1) bu

G. G. Nyambuya

This reading is a continuation of the earlier reading Nyambuya (2008); where three new Curved Spacetime Dirac Equations have been derived mainly to try and account in a natural way for the observed anomalous gyromagnetic ratio of fermions and the suggestions is that particles including the Electron, which is thought to be a point particle, do have a finite s

Nathan Geer, Bertrand Patureau-Mirand, Vladimir Turaev

In this paper we give a re-normalization of the Reshetikhin-Turaev quantum invariants of links, by modified quantum dimensions. In the case of simple Lie algebras these modified quantum dimensions are proportional to the usual quantum dimensions. More interestingly we will give two examples where the usual quantum dimensions vanish but the modified quantum d

Frank Morgan

We prove the existence of a perimeter-minimizing partition of R^n into regions of unit volume. We conclude with a short tribute to the late Manuel A. Fortes.

Mario A. Acero, Carlo Giunti, Marco Laveder

The deficit observed in the Gallium radioactive source experiments is interpreted as a possible indication of the disappearance of electron neutrinos. In the effective framework of two-neutrino mixing we obtain $\sin^{2}2\vartheta \gtrsim 0.03$ and $Δ{m}^{2} \gtrsim 0.1 \text{eV}^{2}$. The compatibility of this result with the data of the Bugey and Chooz rea

J. Kluson

This paper is devoted to the study of dynamics of fundamental string and D1-brane in I-brane background. We consider configurations where string and D1-brane uniformly wrap transverse spheres. We explicitly determine corresponding conserved charges and find relations between them.

Ingrid Van Keilegom, César Sánchez Sellero, Wenceslao González Manteiga

Consider a random vector $(X,Y)$ and let $m(x)=E(Y|X=x)$. We are interested in testing $H_0:m\in {\cal M}_{Θ,{\cal G}}=\{γ(\cdot,θ,g):θ\in Θ,g\in {\cal G}\}$ for some known function $γ$, some compact set $Θ\subset $IR$^p$ and some function set ${\cal G}$ of real valued functions. Specific examples of this general hypothesis include testing for a parametric r

J. A. Bergstra, C. A. Middelburg

We study sequential programs that are instruction sequences with dynamically instantiated instructions. We define the meaning of such programs in two different ways. In either case, we give a translation by which each program with dynamically instantiated instructions is turned into a program without them that exhibits on execution the same behaviour by inte

Yakov Itin

The possible extensions of GR for description of fermions on a curved space, for supergravity and for loop quantum gravity require a richer set of 16 independent variables. These variables can be assembled in a coframe field, i.e., a local set of four linearly independent 1-forms. In the ordinary formulation, the coframe gravity does not have any connection

Jeffrey Burdges

We show that a minimal counter example to the Cherlin-Zilber Algebraicity Conjecture for simple groups of finite Morley rank has Prufer 2-rank at most two. This article covers the signalizer functor theory and identifies the groups of Lie rank at least three; leaving the uniqueness case analysis to previous articles. This result signifies the end of the gene

Elena Villa

The mean density of a random closed set $Θ$ in $\R^d$ with Hausdorff dimension $n$ is the Radon-Nikodym derivative of the expected measure $\E[\h^n(Θ\cap\cdot)]$ induced by $Θ$ with respect to the usual $d$-dimensional Lebesgue measure. We consider here inhomogeneous Boolean models with lower dimensional typical grain. Under general regularity assumptions on

Scipio Cuccagna, Tetsu Mizumachi

We consider nonlinear Schrödinger equations in dimension 3 or higher. We prove that symmetric finite energy solutions close to orbitally stable ground states converge asymptotically to a sum of a ground state and a dispersive wave assuming the so called Fermi Golden Rule (FGR) hypothesis. We improve the sign condition required in a recent paper by Gang Zhou

G. T. van Belle, G. van Belle, M. J. Creech-Eakman, J. Coyne

The Palomar Testbed Interferometer (PTI) archive of observations between 1998 and 2005 is examined for objects appropriate for calibration of optical long-baseline interferometer observations - stars that are predictably point-like and single. Approximately 1,400 nights of data on 1,800 objects were examined for this investigation. We compare those observati

Ping Xi, Xin-zhou Li

We study the quasinormal modes (QNMs) for stringy black holes. By using numerical calculation, the relations between the QNMs and the parameters of black holes are minutely shown. For (1+1)-dimensional stringy black hole, the real part of the quasinormal frequency increases and the imaginary part of the quasinormal frequency decreases as the mass of the blac

Scipio Cuccagna

We transpose work by T.Mizumachi to prove smoothing estimates for dispersive solutions of the linearization at a ground state of a Nonlinear Schr\"odinger equation (NLS) in 1D. As an application we extend to dimension 1D a result on asymptotic stability of ground states of NLS proved by Cuccagna & Mizumachi for dimensions $\ge 3$

Masafumi Fukuma, Ken-Ichi Katayama, Takao Suyama

Three-dimensional Yang-Mills theory is investigated in the Hamiltonian formalism based on the Karabali-Nair variable. A new algorithm is developed to obtain the renormalized Hamiltonian by identifying local counterterms in Lagrangian with the use of fictitious holomorphic symmetry existing in the framework with the KN variable. Our algorithm is totally algeb

Hideo Kodama

We discuss the relation between the superradiance phenomenon and the instability of rotating black holes in higher dimensions. In particular, we point out that the superradiant instability of a massless scalar field around a simply rotating Kerr-adS black hole implies the gravitational instability of that black hole for tensor-type perturbations.

Reiho Sakamoto

The Kirillov--Schilling--Shimozono (KSS) bijection appearing in theory of the Fermionic formula gives an one to one correspondence between the set of elements of tensor products of the Kirillov--Reshetikhin crystals (called paths) and the set of rigged configurations. It is a generalization of Kerov--Kirillov--Reshetikhin bijection and plays inverse scatteri

Clayton Bjorland, Maria E. Schonbek

We consider the steady-state Navier-Stokes equation in the whole space $\mathbb{R}^3$ driven by a forcing function $f$. The class of source functions $f$ under consideration yield the existence of at least one solution with finite Dirichlet integral ($\|\nabla U\|_2<\infty$). Under the additional assumptions that $f$ is absent of low modes and the ratio of $

Zdenka Misanovic, George Pavlov, Gordon Garmire

We report on two Chandra observations of the 3-Myr pulsar B1929+10, which reveal a faint compact (~9&#34;x5&#34;) nebula elongated in the direction perpendicular to the pulsar&#39;s proper motion, two patchy wings, and a possible short (~3&#34;) jet emerging from the pulsar. In addition, we detect a tail extending up to at least 4&#39; in the direction oppos

Angelia Nedić, Alex Olshevsky, Asuman Ozdaglar, John Tsitsiklis

We consider distributed iterative algorithms for the averaging problem over time-varying topologies. Our focus is on the convergence time of such algorithms when complete (unquantized) information is available, and on the degradation of performance when only quantized information is available. We study a large and natural class of averaging algorithms, which

Michael Eichmair

We solve the Plateau problem for marginally outer trapped surfaces in general Cauchy data sets. We employ the Perron method and tools from geometric measure theory to force and control a blow-up of Jang&#39;s equation. Substantial new geometric insights regarding the lower order properties of marginally outer trapped surfaces are gained in the process. The t

Nobuyuki Kanematsu, Shunsuke Yonai, Azusa Ishizaki, Masami Torikoshi

A model for beam customization with collimators and a range-compensating filter based on the phase-space theory for beam transport is presented for dose distribution calculation in treatment planning of radiotherapy with protons and heavier ions. Independent handling of pencil beams in conventional pencil-beam algorithms causes unphysical collimator-height d

M. F. Gelin, D. S. Kosov

We present a unified and simple method for deriving work theorems for classical and quantum Hamiltonian systems, both under equilibrium conditions and in a steady state. Throughout the paper, we adopt the partitioning of the total Hamiltonian into the system part, the bath part, and their coupling. We rederive many equalities which are available in the liter

M. R. Vanner, R. J. McLean, A. I. Sidorov, P. Hannaford

We report on a tunable all-optical delay line for pulses with optical frequency within the Rb $D_2$ absorption line. Using frequency tuning between absorption components from different isotopes, pulses of 10 ns duration are delayed in a 10 cm hot vapour cell by up to 40 ns while the transmission remains above 10%. The use of two isotopes allows the delay to

Paulo F. Farinas

Dynamics of the magnetization in ferromagnets is examined in the presence of transport electrons allowing the latter to interact. It is found that the existence of inhomogeneities such as domain wall (DW) structures, leads to changes that affect the dynamical structure of the equations of motion for the magnetization. Only in the limit of uniform magnetizati

Tao Zhou, Hoang Anh Tuan Kiet, Beom Jun Kim, Bing-Hong Wang

The human society is a very complex system; still, there are several non-trivial, general features. One type of them is the presence of power-law distributed quantities in temporal statistics. In this Letter, we focus on the origin of power-laws in rating of movies. We present a systematic empirical exploration of the time between two consecutive ratings of

Kaspar von Braun, David R. Ciardi

Window functions describe, as a function of orbital period, the probability that an existing planetary transit is detectable in one&#39;s data for a given observing strategy. We show the dependence of this probability upon several strategy and astrophysical parameters, such as length of observing run, observing cadence, length of night, and transit duration.

M. Kulkarni, N. Seshadri, V. S. C. Manga Rao, S. Dutta Gupta

We consider pulse propagation through a two component composite medium (metal inclusions in a dielectric host) with or without cavity mirrors. We show that a very thin slab of such a medium, under conditions of localized plasmon resonance, can lead to significant superluminality with detectable levels of transmitted pulse. A cavity containing the heterogeneo

S. Gomez-Avila, M. Napsuciale, E. Oset

In this work we study the e^{+}e^{-}\toϕK^{+}K^{-} reaction. The leading order electromagnetic contributions to this process involve the γ*ϕ K^{+}K^{-} vertex function with a highly virtual photon. We calculate this function at low energies using RχPT supplemented with the anomalous term for the VV&#39;P interactions. Tree level contributions involve the kao

Stathis Livadas

In this article I deal with the notion of observation in the most fundamental sense and its representation by means of formal languages serving as expressional tools of formal-axiomatical theories. In doing so, I have taken this notion in two diverse contexts. In the first as an epistemic notion that refers to its interpretation in a formal mathematical envi

Donald C. Ellison, Andrey Vladimirov

Evidence is accumulating suggesting that collisionless shocks in supernova remnants (SNRs) can amplify the interstellar magnetic field to hundreds of microgauss or even milli-gauss levels, as recently claimed for SNR RX J1713.7-3946. If these fields exist, they are almost certainly created by magnetic field amplification (MFA) associated with the efficient p

Rafael Martinez, Manuel Cebrian, Francisco de Borja Rodriguez, David Camacho

The main contribution of this paper is to design an Information Retrieval (IR) technique based on Algorithmic Information Theory (using the Normalized Compression Distance- NCD), statistical techniques (outliers), and novel organization of data base structure. The paper shows how they can be integrated to retrieve information from generic databases using lon

Chen-Zhou CUI, Hua-Ping SUN, Yong-Heng ZHAO, Yu LUO

With the development of network and the World Wide Web (WWW), the Internet has been growing and changing dramatically. More and more on-line database systems and different kinds of services are available for astronomy research. How to help users find their way through the jungle of information services becomes an important challenge. Although astronomers hav

Daniel P. Snowman

This work analyzes the distribution and size of interparticle gaps arising in an ensemble of hexagonal unit structures in the xy plane when packing disks with a Gaussian distribution of radii with mean (r) and standard deviation $Δr$. During the course of this investigation an equivalency is established between gaps arising in hexagonal unit structure packs

V. E. Nazaikinskii, A. Yu. Savin, B. Yu. Sternin

The aim of this paper is to construct the Poincare isomorphism in K-theory on manifolds with edges. We show that the Poincare isomorphism can naturally be constructed in the framework of noncommutative geometry. More precisely, to a manifold with edges we assign a noncommutative algebra and construct an isomorphism between the K-group of this algebra and the

Chenzhou Cui, Yongheng Zhao

Virtual Observatory (VO) is a data intensive online astronomical research and education environment, taking advantages of advanced information technologies to achieve seamless and uniform access to astronomical information. The concept of VO was introduced in late of 1990s to meet challenges brought up with data avalanche in astronomy. This paper reviews cur

Allen L. Mann

Independence-friendly logic is a conservative extension of first-order logic that has the same expressive power as existential second-order logic. In her Ph.D. thesis, Dechesne introduces a variant of independence-friendly logic called IFG logic. We attempt to algebraize IFG logic in the same way that Boolean algebra is the algebra of propositional logic and

Adam Lidz, Oliver Zahn, Matthew McQuinn, Matias Zaldarriaga

We forecast the sensitivity with which the Murchison Widefield Array (MWA) can measure the 21 cm power spectrum of cosmic hydrogen, using radiative transfer simulations to model reionization and the 21 cm signal. The MWA is sensitive to roughly a decade in scale (wavenumbers of k ~ 0.1 - 1 h Mpc^{-1}), with foreground contamination precluding measurements on

M. G. Rickes, M. G. Pastoriza, Ch Bonatto

In this work we investigate the stellar population, metallicity distribution and ionized gas in the elliptical galaxy NGC 5044, using long-slit spectroscopy and a stellar population synthesis method. We found differences in the slope of metal-line profiles along the galaxy which suggests an enhancement of alpha elements, particularly towards the central regi

John Quah, Dionisios Margetis

We study the continuum limit in 2+1 dimensions of nanoscale anisotropic diffusion processes on crystal surfaces relaxing to become flat below roughening. Our main result is a continuum law for the surface flux in terms of a new continuum-scale tensor mobility. The starting point is the Burton, Cabrera and Frank (BCF) theory, which offers a discrete scheme fo

Thomas P. Robitaille

In this contribution, I review the applications and potential limitations of the spectral energy distribution fitting tool that I have developed, with a strong emphasis on the limits to which this tool can be used to improve our understanding of massive star formation. I discuss why our current grid of models cannot be used to distinguish between the several

Silvia Onofrei

We study locally truncated geometries that are parapolar spaces locally of type A_{n-1,j}(K) with n>6 and j=3,4. Residually connected sheaves over these geometries are constructed. It is proved that these geometries are residually connected diagram geometries whose universal 2-covers are truncations of buildings.

Yanling Wu, V. Charmandaris, J. R. Houck, J. Bernard-Salas

We study the correlation between the radio, mid-infrared and far-infrared properties for a sample of 28 blue compact dwarf (BCD) and low metallicity star-forming galaxies observed by Spitzer. We find that these sources extend the same far-infrared to radio correlation typical of star forming late type alaxies to lower luminosities. In BCDs, the 24um (or 22um

Robert J. Hinde

We present a six-dimensional potential energy surface for the H2-H2 dimer based on ab initio electronic structure calculations. The surface is intended to describe accurately the bound and quasibound states of the dimers H2-H2, D2-D2, and H2-D2 that correlate with H2 or D2 monomers in the rovibrational levels (v, j) = (0, 0), (0, 2), (1, 0), and (1, 2). We u

Sukanya Chakrabarti, Barbara Whitney

We present three-dimensional, self-consistent radiative transfer solutions with a new Monte Carlo radiative equilibrium code. The code, RADISHE ($\bf{RAD}$iative transfer $\bf{I}$n $\bf{S}$moothed particle $\bf{H}$ydrodynamics and $\bf{E}$ulerian codes), can be applied to calculate the emergent spectral energy distributions (SEDs) and broadband images from o

J. Meaburn, M. Lloyd, N. M. H. Vaytet, J. A. López

The ouflowing proper motions of fifteen knots in the dominant northwestern lobe of the high-excitation poly-polar planetary nebula NGC 6302 have been determined by comparing their positions relative to those of faint stars in an image taken at the San Pedro Martir Observatory in 2007 to those in a South African Astronomical Observatory archival plate obtaine

G. G. Howes

The transfer of turbulent energy through an inertial range from the driving scale to dissipative scales in a kinetic plasma followed by the conversion of this energy into heat is a fundamental plasma physics process. A theoretical foundation for the study of this process is constructed, but the details of the kinetic cascade are not well understood. Several

S. K. Donaldson

We give an elementary argument to compute the $α$-invariant of this Fano 3-fold, which implies the existence of a Kahler-Einstein metric.

S. Bilir, S. Ak, S. Karaali, A. Cabrera-Lavers

We present colour transformations for the conversion of the {\em 2MASS} photometric system to the Johnson-Cousins $UBVRI$ system and further into the {\em SDSS} $ugriz$ system. We have taken {\em SDSS} $gri$ magnitudes of stars measured with the 2.5-m telescope from $SDSS$ Data Release 5 (DR5), and $BVRI$ and $JHK_{s}$ magnitudes from Stetson&#39;s catalogue

G. G. Howes, W. Dorland, S. C. Cowley, G. W. Hammett

This letter presents the first ab initio, fully electromagnetic, kinetic simulations of magnetized turbulence in a homogeneous, weakly collisional plasma at the scale of the ion Larmor radius (ion gyroscale). Magnetic and electric-field energy spectra show a break at the ion gyroscale; the spectral slopes are consistent with scaling predictions for criticall

Erik Rosolowsky, Joshua D. Simon

We present a new determination of the metallicity gradient in M33, based on Keck/LRIS measurements of oxygen abundances using the temperature-sensitive emission line [OIII] 4363 A in 61 HII regions. These data approximately triple the sample of direct oxygen abundances in M33. We find a central abundance of 12 + log(O/H) = 8.36+/-0.04 and a slope of -0.027+/

Nicolas Laflorencie, Erik S. Sørensen, Ian Affleck

The free electron Kondo problem can be described by a one-dimensional (1D) model because only the s-wave part of the electronic wave-function is affected by the Kondo coupling. Since only the spin degrees of freedom are involved in the Kondo interaction, and due to spin-charge separation in 1D, the universal low energy long distance physics of the Kondo mode

Todd C. Hillwig, Douglas R. Gies

The microquasar SS 433 is an interacting massive binary consisting of an evolved mass donor and a compact companion that ejects relativistic jets. The mass donor was previously identified through spectroscopic observations of absorption lines in the blue part of the spectrum that showed Doppler shifts associated with orbital motion and strength variations re

John Maginnis, Silvia Onofrei

We determine the nature of the fixed point sets of groups of order p, acting on complexes of distinguished p-subgroups (those p-subgroups containing p-central elements in their centers). The case when G has parabolic characteristic p is analyzed in detail.

Italo J. Dejter, Abel A. Delgado

A dominating set $S$ in a graph $G$ is said to be perfect if every vertex of $G$ not in $S$ is adjacent to just one vertex of $S$. Given a vertex subset $S&#39;$ of a side $P_m$ of an $m\times n$ grid graph $G$, the perfect dominating sets $S$ in $G$ with $S&#39;=S\cap V(P_m)$ can be determined via an exhaustive algorithm $Θ$ of running time $O(2^{m+n})$. Ex

André Neves, Gang Tian

We prove some non-existence theorems for translating solutions to Lagrangian mean curvature flow. More precisely, we show that translating solutions with an $L^2$ bound on the mean curvature are planes and that almost-calibrated translating solutions which are static are also planes. Recent work of D. Joyce, Y.-I. Lee, and M.-P. Tsui, shows that these condit

Herry J. Kwee, Richard F. Lebed

We prove an identity [Eq. (1) below] among SU(2) 6j and 9j symbols that generalizes the Biedenharn-Elliott sum rule. We prove the result using diagrammatic techniques (briefly reviewed here), and then provide an algebraic proof. This identity is useful for studying meson-baryon scattering in which an extra isoscalar meson is produced.

Matthew S. Dyer, Mats Persson

The free-electron-like state observed in a scanning tunneling spectroscopy study of a chiral p(2x4) monolayer of glycinate ions on the Cu(100) surface [K. Kanazawa et al, J. Am. Chem. Soc. 129, 740 (2007)] is shown from density functional theory calculations to originate from a Cu Shockley surface state at the surface Brillouin zone boundary of the clean sur

Iain Gordon, Emil Horozov, Milen Yakimov

We prove a criterion for the reality of irreducible representations of the rational Cherednik algebras H_{0,1}(S_n). This is shown to imply a criterion for the real loci of the Calogero-Moser spaces C_n in terms of the Etingof-Ginzburg finite maps Υ\colon C_n \to C^n/S_n \times C^n/S_n, recovering a result of Mikhin, Tarasov, and Varchenko [MTV2]. As a conse

Andre Neves

We construct a solution to inverse mean curvature flow on an asymptotically hyperbolic 3-manifold which does not have the convergence properties needed in order to prove a Penrose--type inequality. This contrasts sharply with the asymptotically flat case. The main idea consists in combining inverse mean curvature flow with work done by Shi--Tam regarding bou

William J. Henney, R. J. R. Williams, Gary J. Ferland, Gargi Shaw

The hydrogen ionization and dissociation front around an ultraviolet radiation source should merge when the ratio of ionizing photon flux to gas density is sufficiently low and the spectrum is sufficiently hard. This regime is particularly relevant to the molecular knots that are commonly found in evolved planetary nebulae, such as the Helix Nebula, where tr

A. Palacios, T. N. Rescigno, C. W. McCurdy

In a previous publication, procedures were proposed for unambiguously extracting amplitudes for single and double ionization from a time-dependent wavepacket by effectively propagating for an infinite time following a radiation pulse. Here we demonstrate the accuracy and utility of those methods for describing two-photon single and one-photon double ionizati

Andre Neves, Gang Tian

In a previous paper, the authors showed that metrics which are asymptotic to Anti-de Sitter-Schwarzschild metrics with positive mass admit a unique foliation by stable spheres with constant mean curvature. In this paper we extend that result to all asymptotically hyperbolic metrics for which the trace of the mass term is positive. We do this by combining the

R. Marques, F. Mesa, L. Jelinek, J. D. Baena

Some novel quasi-planar chiral inclusions, feasible from standard photo-etching techniques, are proposed. It is shown that such inclusions can be designed in order to present balanced electric, magnetic and magneto-electric polarizabilities. Using these inclusions, random and periodic bi-isotropic artificial metamaterials exhibiting a balanced positive/negat

Akhlesh Lakhtakia, Joseph B. Geddes, Tom G. Mackay

Two choices are possible for the refractive index of a linear, homogeneous, isotropic, active, dielectric material. Either of the choices is adequate for obtaining frequency-domain solutions for (i) scattering by slabs, spheres, and other objects of bounded extent; (ii) guided-wave propagation in homogeneously filled, cross-sectionally uniform, straight wave