September 2007 arXiv papers — page 41

Nigel B. Wilding, Peter Sollich, Matteo Buzzacchi

We describe a lattice-gas model suitable for studying the generic effects of polydispersity on liquid-vapor phase equilibria. Using Monte Carlo simulation methods tailored for the accurate determination of phase behaviour under conditions of fixed polydispersity, we trace the cloud and shadow curves for a particular Schulz distribution of the polydisperse at

Enno Mammen, Kyusang Yu

This paper is about optimal estimation of the additive components of a nonparametric, additive isotone regression model. It is shown that asymptotically up to first order, each additive component can be estimated as well as it could be by a least squares estimator if the other components were known. The algorithm for the calculation of the estimator uses bac

M. Guedel, A. Telleschi

We study an anomaly in the X-ray flux (or luminosity) ratio between the OVII 21.6-22.1A triplet and the OVIII Lya line seen in classical T Tauri stars (CTTS). This ratio is unusually high when compared with ratios for main-sequence and non-accreting T Tauri stars (Telleschi et al. 2007). We compare these samples to identify the source of the excess. A sample

Alberto Zobelli, Alexandre Gloter, Chris P. Ewels, Christian Colliex

We show that electron irradiation in a dedicated scanning transmission microscope can be used as a nano-electron-lithography technique allowing the controlled reshaping of single walled carbon and boron nitride nanotubes. The required irradiation conditions have been optimised on the basis of total knock-on cross sections calculated within density functional

Heinrich Niederhausen, Shaun Sullivan

Counting pattern avoiding ballot paths begins with a careful analysis of the pattern. Not the length, but the characteristics of the pattern are responsible for the difficulties in finding explicit solutions. Certain features, like overlap and difference in number of right and up steps determine the solution of the recursion formula. If the recursion can be

Michael S. Kelley, William T. Reach, David J. Lien

We report the detection of comet 67P/Churyumov-Gerasimenko's dust trail and nucleus in 24 micron Spitzer Space Telescope images taken February 2004. The dust trail is not found in optical Palomar images taken June 2003. Both the optical and infrared images show a distinct neck-line tail structure, offset from the projected orbit of the comet. We compare

I. Brott, I. Hunter, P. Anders, N. Langer

The VLT-Flames Survey for Massive Stars (Evans05,Evans06) provides recise measurements of rotational velocities and nitrogen surface abundances of massive stars in the Magellanic Clouds. Specifically, for the first time, such abundances have been estimated for stars with significant rotational velocities. This extraordinary data set gives us the unique possi

C. Bogdanos, A. Kehagias, K. Tamvakis

We consider a model involving a 4-brane in a 6D bulk which carries sigma model fields. An axion field on the 4-brane cancels the pressure along one direction leading to an effective codimension-2 3-brane. For a range of parameters of the theory, we get a transverse space which is non-compact, providing a possible solution to the cosmological constant problem

Martin Bojowald, Golam Mortuza Hossain

In contrast to scalar and tensor modes, vector modes of linear perturbations around an expanding Friedmann--Robertson--Walker universe decay. This makes them largely irrelevant for late time cosmology, assuming that all modes started out at a similar magnitude at some early stage. By now, however, bouncing models are frequently considered which exhibit a col

Yuliya V. Martsynyuk

This paper deals simultaneously with linear structural and functional error-in-variables models (SEIVM and FEIVM), revisiting in this context generalized and modified least squares estimators of the slope and intercept, and some methods of moments estimators of unknown variances of the measurement errors. New joint central limit theorems (CLT's) are esta

James E. Lidsey, Karim A. Malik

Oscillating moduli fields can support a cosmological scaling solution in the presence of a perfect fluid when the scalar field potential satisfies appropriate conditions. We examine when such conditions arise in higher-dimensional, non-linear sigma-models that are reduced to four dimensions under a generalized Scherk-Schwarz compactification. We show explici

S. Froehlich, F. Mueller

We study orthonormal normal sections of two-dimensional immersions in $\mathbb R^{n+2},$ $n\ge 2$, at which these sections are critical for a functional of total torsion. In particular, we establish upper bounds for the torsion coefficients in the case of non-flat normal bundles. With these notes we continue a foregoing paper on surfaces in $\mathbb R^4.$

Adrian Belu, Eric Thiébaut, Marc Ollivier, Guilaine Lagache

Instrumental projects that will improve the direct optical finding and characterisation of exoplanets have advanced sufficiently to trigger organized investigation and development of corresponding signal processing algorithms. The first step is the availability of field-of-view (FOV) models. These can then be submitted to various instrumental models, which i

Jian Huang, Huiliang Xie

We study the asymptotic properties of the SCAD-penalized least squares estimator in sparse, high-dimensional, linear regression models when the number of covariates may increase with the sample size. We are particularly interested in the use of this estimator for simultaneous variable selection and estimation. We show that under appropriate conditions, the S

E. Byrne, M. Greferath, T. Honold

It is known that a linear two-weight code $C$ over a finite field $\F_q$ corresponds both to a multiset in a projective space over $\F_q$ that meets every hyperplane in either $a$ or $b$ points for some integers $a<b$, and to a strongly regular graph whose vertices may be identified with the codewords of $C$. Here we extend this classical result to the case

Rich Townsend

In this contribution, I discuss some basic techniques that can be used to simulate radiative transfer through porous media. As specific examples, I consider scattering transfer through a clumped slab, and X-ray emission line formation in a clumped wind.

T. J. Bronder, I. M. Hook, P. Astier, D. Balam

Aims: We present a quantitative study of a new data set of high redshift Type Ia supernovae spectra, observed at the Gemini telescopes during the first 34 months of the Supernova Legacy Survey. During this time 123 supernovae candidates were observed, of which 87 have been identified as SNe Ia at a median redshift of z=0.720. Spectra from the entire second y

D. G. Cerdeno, T. Kobayashi, C. Munoz

We analyse the phenomenology of orbifold scenarios from the heterotic superstring, and the resulting theoretical predictions for the direct detection of neutralino dark matter. In particular, we study the parameter space of these constructions, computing the low-energy spectrum and taking into account the most recent experimental and astrophysical constraint

R. S. Pasechnik, A. Szczurek, O. V. Teryaev

We calculate several differential distributions for exclusive double diffractive $χ_c(0^{++})$ production in proton-antiproton collisions at the Tevatron and in proton-proton collisions at RHIC and LHC in terms of unintegrated gluon distributions (UGDFs) within the $k_t$-factorisation approach. The uncertainties of the Khoze-Martin-Ryskin approach are discus

Thierry Masson

This is an extended version of a communication made at the international conference ``Noncommutative Geometry and Physics&#39;&#39; held at Orsay in april 2007. In this proceeding, we make a review of some noncommutative constructions connected to the ordinary fiber bundle theory. The noncommutative algebra is the endomorphism algebra of a SU(n)-vector bundl

Koenraad M. R. Audenaert

A problem in quantum information theory that has received considerable attention in recent years is the question of multiplicativity of the so-called maximal output purity (MOP) of a quantum channel. This quantity is defined as the maximum value of the purity one can get at the output of a channel by varying over all physical input states, when purity is mea

Yann Bugeaud, Simon Kristensen

We are studying the Diophantine exponent μ_{n,l}$ defined for integers 1 \leq l < n and a vector α\in \mathbb{R}^n by letting μ_{n,l} = \sup{μ\geq 0: 0 < ||x \cdot α|| < H(x)^{-μ} for infinitely many x \in C_{n,l} \cap \mathbb{Z}^n}, where \cdot is the scalar product and || . || denotes the distance to the nearest integer and C_{n,l} is the generalised cone

Anton Cox, Maud De Visscher, Stephen Doty, Paul Martin

We determine the blocks of the walled Brauer algebra in characteristic zero. These can be described in terms of orbits of the action of a Weyl group of type $A$ on a certain set of weights. In positive characteristic we give a linkage principle in terms of orbits of the corresponding affine Weyl group. We also classify the semisimple walled Brauer algebras i

Donald Yau

Enveloping algebras of Hom-Lie and Hom-Leibniz algebras are constructed.

R. P. S. M. Lobo, R. L. Moreira, D. Lebeugle, D. Colson

We discuss the first infrared reflectivity measurement on a BiFeO3 single crystal between 5 K and room temperature. The 9 predicted ab-plane E phonon modes are fully and unambiguously determined. The frequencies of the 4 A1 c-axis phonons are found. These results settle issues between theory and data on ceramics. Our findings show that the softening of the l

B. M. Shergelashvili, C. Maes, S. Poedts, T. V. Zaqarashvili

The propagation of compressional MHD waves is studied for an externally driven system. It is assumed that the combined action of the external sources and sinks of the entropy results in the harmonic oscillation of the entropy (and temperature) in the system. It is found that with the appropriate resonant conditions fast and slow waves get amplified due to th

Wei-Liang Qian, Rone Andrade, Frederique Grassi, Yogiro Hama

Thermal model fit indicates early chemical freeze-out of multi-strange hadrons with small collective velocities at 200AGeV Au-Au collisions at RHIC. In this work, we present our recent results by SPheRIO hydrodynamical calculations inspired by this picture. In our model, multi-strange hadrons go through chemical freeze-out when the system reaches some temper

Sara A. van de Geer

We study a high-dimensional generalized linear model and penalized empirical risk minimization with $\ell_1$ penalty. Our aim is to provide a non-trivial illustration that non-asymptotic bounds for the estimator can be obtained without relying on the chaining technique and/or the peeling device.

Yu. V. Gaponov

Two mathematical models based on Pauli transformations including U(1) chiral group and Pauli SU(2) group, that mixes particle and antiparticle states, are developed for description of Majorana properties of neutral particles. The first one describes a system, incorporating left- and right-handed fermions of the same flavor, and it is a generalization of the

Andras Nemethi

For any negative definite plumbed 3-manifold M we construct from its plumbed graph a graded Z[U]-module. This, for rational homology spheres, conjecturally equals the Heegaard-Floer homology of Ozsvath and Szabo, but it has even more structure. If M is a complex singularity link then the normalized Euler-characteristic can be compared with the analytic invar

A. Agliolo Gallitto, M. Bonura, M. Li Vigni

We report experimental results of the field-induced variations of the microwave surface resistance in samples of MgB2, produced by different methods. By sweeping the DC magnetic field at increasing and decreasing values, we have detected a magnetic hysteresis that can be ascribed to the different magnetic induction, due to the critical state of the fluxon la

T. V. Ramakrishnan

I briefly survey here attempts to model the rich and strange behaviour of colossal magnetoresistance manganites, after outlining some of the phenomena observed in them, and describing the three relevant strong local interactions of the e_g electrons (in two different orbital states at each site), namely with Jahn-Teller phonon modes (strength g), with reside

Boris Podobnik, Davor Horvatic, Alfonso Lam Ng, H. Eugene Stanley

We investigate how simultaneously recorded long-range power-law correlated multi-variate signals cross-correlate. To this end we introduce a two-component ARFIMA stochastic process and a two-component FIARCH process to generate coupled fractal signals with long-range power-law correlations which are at the same time long-range cross-correlated. We study how

Claudio Pisani

A certain amount of category theory is developed in an arbitrary finitely complete category with a factorization system on it, playing the role of the comprehensive factorization system on Cat. Those aspects related to the concepts of finality (in particular terminal objects), discreteness and components, representability, colimits and universal arrows, seem

J. Rohrwild

The radiative $Δ\to γN$ transition is examined at the real photon point $Q^2=0$ using the framework of light-cone QCD sum rules. In particular, we determine the sum rules for the transition form factors $G_M(0)$ and $R_{EM}$ up to twist 4.

C. A. Dominguez, R. Röntsch

The three electromagnetic form factors of the $Δ(1232)$ resonance, $G^*_M(q^2)$, $G^*_E(q^2)$, and $G^*_C(q^2)$ are obtained in the space-like region using a Dual Resonance Model realization of QCD in the large $N_c$ limit (Dual-${QCD}_{\infty}$). Each form factor involves a single free parameter which is fixed by fitting data on $G^*_M(q^2)$, and on the rat

Yoshihiro Aoki, Akihiko Sumiyama, Gaku Motoyama, Yasukage Oda

We have investigated the pressure dependence of ac and dc susceptibilities of the heavy-fermion superconductor CePt3Si (Tc= 0.75 K) that coexists with antiferromagnetism (TN = 2.2 K). As hydrostatic pressure is increased, Tc first decreases rapidly, then rather slowly near the critical pressure Pc = 0.6 GPa and shows a stronger decrease again at higher press

Nikos Prantzos

The formalism of the simple model of galactic chemical evolution (GCE) and its main ingredients (stellar properties, initial mass function, star formation rate and gas flows) are presented in this tutorial. It is stressed that GCE is not (yet) an astrophysical theory, but it merely provides a framework in which the large body of data concerning the chemical

Daniel J. Price

This paper presents SPLASH, a publicly available interactive visualisation tool for Smoothed Particle Hydrodynamics (SPH) simulations. Visualisation of SPH data is more complicated than for grid-based codes because the data is defined on a set of irregular points and therefore requires a mapping procedure to a two dimensional pixel array. This means that, in

Anna Salvati, Sandra Ristori, Julian Oberdisse, Olivier Spalla

In this work the physicochemical characterization of liposomes loaded with a newly synthesised carboranyl porphyrazine (H2HECASPz) is described. This molecule represents a potential drug for different anticancer therapies, such as Boron Neutron Capture Therapy, Photodynamic Therapy and Photothermal Therapy. Different loading methods and different lipid mixtu

M. Cantiello, S. -C. Yoon, N. Langer, M. Livio

The collapsar model for long gamma-ray bursts requires a rapidly rotating Wolf-Rayet star as progenitor. We test the idea of producing rapidly rotating Wolf-Rayet stars in massive close binaries through mass accretion and consecutive quasi-chemically homogeneous evolution; the latter had previously been shown to provide collapsars below a certain metallicity

S. E. A. Orrigo, H. Lenske, F. Cappuzzello, A. Cunsolo

Fano Resonances are a new continuum excitation mode in light exotic nuclei. By the QPC model we explain these sharp and asymmetric structures as due to the coupling of a single particle elastic channel to the closed core-excited channels. Theoretical model calculations are compared for 15C, 17C and 19C. The theoretical results for 15C are in qualitative agre

Frederic Zagury

The hypothesis of an extended red emission (ERE) in diffuse Galactic light (DGL) has been put forward in 1998 by Gordon, Witt and Friedmann who found that scattered starlight was not enough to explain the amount of DGL in the R band, in some high Galactic latitude directions. This paper re-investigates, for high Galactic latitudes, the brightnesses and colou

Muhammad Akashi

We conduct 2D axisymmetrical hydrodynamical simulations to investigate the interaction of a collimated fast wind (CFW; wide jets) with a spherical AGB wind. The code includes radiative cooling. We find that the shape of the planetary nebula (PN) is sensitive to the exact mass loss history of the AGB wind, and the opening angle of the CFW. Some typical PN mor

Koenraad M. R. Audenaert, Stefan Scheel

In this article we provide necessary and sufficient conditions for a completely positive trace-preserving (CPT) map to be decomposable into a convex combination of unitary maps. Additionally, we set out to define a proper distance measure between a given CPT map and the set of random unitary maps, and methods for calculating it. In this way one could determi

Carsten Marr, Mark Mueller-Linow, Marc-Thorsten Huett

In a recent paper [C. Marr, M. Mueller-Linow, and M.-T. Huett, Phys. Rev. E 75, 041917 (2007)] we discuss the pronounced potential of real metabolic network topologies, compared to randomized counterparts, to regularize complex binary dynamics. In their comment [P. Holme and M. Huss, arXiv:0705.4084v1], Holme and Huss criticize our approach and repeat our st

Peter Müller, Christoph Richard

We study randomly coloured graphs embedded into Euclidean space, whose vertex sets are infinite, uniformly discrete subsets of finite local complexity. We construct the appropriate ergodic dynamical systems, explicitly characterise ergodic measures, and prove an ergodic theorem. For covariant operators of finite range defined on those graphs, we show the exi

Mareki Honma, Takeshi Bushimata, Yoon Kyung Choi, Tomoya Hirota

We have performed high-precision astrometry of H2O maser sources in Galactic star forming region Sharpless 269 (S269) with VERA. We have successfully detected a trigonometric parallax of 189+/-8 micro-arcsec, corresponding to the source distance of 5.28 +0.24/-0.22 kpc. This is the smallest parallax ever measured, and the first one detected beyond 5 kpc. The

Giorgio Papini

External gravitational fields induce phase factors in the wave functions of particles. The phases are exact to first order in the background gravitational field, are manifestly covariant and gauge invariant and provide a useful tool for the study of spin-gravity coupling and of the optics of particles in gravitational or inertial fields. We discuss the role

F. J. Martinez-Serrano, R. Dominguez-Tenreiro, M. Molla

We have implemented a chemical evolution model on the parallel AP3M+SPH DEVA code which we use to perform high resolution simulations of spiral galaxy formation. It includes feedback by SNII and SNIa using the Qij matrix formalism. We also include a diffusion mechanism that spreads newly introduced metals. The gas cooling rate depends on its specific composi

Natalia Del Fatti, Roland Bouffanais, Fabrice Vallée, Christos Flytzanis

Ultrafast relaxation dynamics of an athermal electron distribution is investigated in silver films using a femtosecond pump-probe technique with 18 fs pulses in off-resonant conditions. The results yield evidence for an increase with time of the electron-gas energy loss rate to the lattice and of the free electron damping during the early stages of the elect

I. Martinez-Valpuesta, J. H. Knapen, R. Buta

Many barred galaxies show a set of symmetric enhancements at the ends of the stellar bar, called {\it ansae}, or the ``handles&#39;&#39; of the bar. The ansa bars have been in the literature for some decades, but their origin has still not been specifically addressed, although, they could be related to the growth process of bars. But even though ansae have b

S. F. Sanchez, J. Aceituno, U. Thiele, D. Perez-Ramirez

We present a characterization of the main properties of the night-sky at the Calar Alto observatory for the time period between 2004 and 2007. We use optical spectrophotometric data, photometric calibrated images taken in moonless observing periods, together with the observing conditions regularly monitored at the observatory, such as atmospheric extinction

Anna Grigorieva, Ph. Thebault, P. Artymowicz, A. Brandeker

We put theoretical constraints on the presence and survival of icy grains in debris discs. Particular attention is paid to UV sputtering of water ice, which has so far not been studied in detail in this context. We present a photosputtering model based on available experimental and theoretical studies. We quantitatively estimate the erosion rate of icy and i

E. Cisana, L. Fermi, G. Montagna, O. Nicrosini

The correlated stochastic volatility models constitute a natural extension of the Black and Scholes-Merton framework: here the volatility is not a constant, but a stochastic process correlated with the price log-return one. At present, several stochastic volatility models are discussed in the literature, differing in the dynamics attached to the volatility.

M. Mahmoudi, M. Sahrai, J. Evers

The propagation of a weak probe field in a laser-driven four-level atomic system is investigated. We choose mercury as our model system, where the probe transition is in the ultraviolet region. A high-resolution peak appears in the optical spectra due to the presence of interacting dark resonances. We show that this narrow peak leads to superluminal light pr

Jerome Rodriguez

Based on spectral simulations, I show how focusing of the X-ray radiations above 10 keV will open a new window for the study of microquasars. With simulations of soft and hard state spectra of Galactic sources, I discuss how SIMBOL-X can help to precisely measure the spin of black holes. Spectral study on short ~1 s time scales will also allow the accretion-

S. Kaviraj, S. Khochfar, K. Schawinski, S. K. Yi

We combine deep UBVRIzJK photometry from the Multiwavelength Survey by Yale-Chile (MUSYC) with redshifts from the COMBO-17 survey to perform a large-scale study of the rest-frame ultraviolet (UV) properties of 674 high-redshift (0.5<z<1) early-type galaxies, drawn from the Extended Chandra Deep Field South (E-CDFS). Galaxy morphologies are determined through

Chang-shui Yu, He-shan Song

We show that for tripartite quantum pure states of qubits, all the kinds of entanglement in terms of SLOCC classification are experimentally measurable by simple projective measurements, provided that four copies of the composite quantum system are available. In particular, the entanglement of reduced density matrices, even though they are mixed states, can

P. Slany, Z. Stuchlik

Critical discussion of the recently published results [Muller, A. and Aschenbach, B. 2007 Class. Quantum Grav. 24, p. 2637; arXiv:0704.3963] on the non-monotonic orbital velocity profiles of the Keplerian motion of test particles and l = const motion of test perfect fluid around K(a)dS black holes is given, and the discrepancies concerned the existence of th

Chang-shui Yu, X. X. Yi, He-shan Song, D. Mei

Schemes to generate Greenberger-Horne-Zeilinger(GHZ) and W states of three distant atoms are proposed in this paper. The schemes use the effects of quantum statistics of indistinguishable photons emitted by the atoms inside optical cavities. The advantages of the schemes are their robustness against detection inefficiency and asynchronous emission of the pho

John Bamberg, Tim Penttila, Csaba Schneider

We show that an elation generalised quadrangle which has p+1 lines on each point, for some prime p, is classical or arises from a flock of a quadratic cone (i.e., is a flock quadrangle).

Constantinos Kalapotharakos, Christos Efthymiopoulos, Nikos Voglis

We address the question of an appropriate choice of basis functions for the self-consistent field (SCF) method of simulation of the N-body problem. Our criterion is based on a comparison of the orbits found in N-body realizations of analytical potential-density models of triaxial galaxies, in which the potential is fitted by the SCF method using a variety of

Sylvain Schwartz, Maxence Rebut, Gilles Feugnet, Joseph Colineau

We study in this Letter the dynamical effects of the limited bandwidth of the control electronics in a solid-state (Nd-YAG) ring laser gyroscope. We derive a stability condition for the rotation-sensing regime in the case of a first-order control loop, showing that the smallest measurable rotation speed depends directly on the cutoff frequency value. Our exp

Maria Joita

We introduce the concept of frame of multipliers in Hilbert modules over pro-C*-algebras and show that many properties of frames in Hilbert C*-modules are valid for frames of multipliers in Hilbert modules over pro-C*-algebras.

Kevin Wildrick

We show that a locally Ahlfors 2-regular and locally linearly locally contractible metric surface is locally quasisymmetrically equivalent to the disk. We also discuss an application of this result to the problem of characterizing surfaces in some Euclidean space that are locally bi-Lipschitz equivalent to an open subset of the plane.

A. K. Arzhnikov, L. V. Dobysheva, M. A. Timirgazin

With density functional theory, studied are the local magnetic moments in Fe-Al alloys depending on concentration and Fe nearest environment. At zero temperature, the system can be in different states: ferromagnetic, antiferromagnetic and spin-spiral waves (SSW) which has a minimum energy. Both SSW and negative moment of Fe atoms with many Al atoms around th

Vladimir Lobaskin, Dmitry Lobaskin, Igor M. Kulic

We report on dynamic properties of a simple model microswimmer composed of three spheres and propelling itself in a viscous fluid by spinning motion of the spheres under zero net torque constraint. At a fixed temperature and increasing the spinning frequency, the swimmer demonstrates a transition from dissipation-dominated to a pumping-dominated motion regim

F. Pfuner, L. Degiorgi. H. R. Ott, A. D. Bianchi, Z. Fisk

We report results of a magneto-optical investigation of the Zintl-phase compound EuIn$_2$P$_2$. The compound orders magnetically at $T_C$=24 K and exhibits concomitant large magnetoresistance effects. For $T\le$50 K and increasing magnetic fields we observe a transfer of spectral weight in $σ_1(ω)$ from energies above 1 eV into the low-energy metallic compon

Jason Abernathy, Klaus Dehmelt, Ralf Diener, Jim Hunt

We describe the goals and present functionality of MarlinTPC, a common software framework for the LC-TPC collaboration based on LCIO, Marlin and other ilcsoft tools.

A. K. Arzhnikov, L. V. Dobysheva

Cementite Fe3C is studied with first-principles calculations. Two possible positions of carbon atoms in the iron sublattice are considered: with prismatic or octahedral environment. Mossbauer spectra (MS) with parameters calculated for both modifications are simulated above and below the Curie temperature. A possibility to detect the change in carbon positio

Kazuhiro Kuwae, Takashi Shioya

We consider an infinitesimal version of the Bishop-Gromov relative volume comparison condition as generalized notion of Ricci curvature bounded below for Alexandrov spaces. We prove a Laplacian comparison theorem for Alexandrov spaces under the condition. As an application we prove a topological splitting theorem.

Taizo Kobayashi, Toshiya Takami, Kin&#39;ya Takahashi, Ryota Mibu

Total computational costs of scientific simulations are analyzed between direct numerical simulations (DNS) and multiphysics simulations (MPS) for sound generation in musical instruments. In order to produce acoustic sound by a turbulent flow in a simple recorder-like instrument, compressible fluid dynamic calculations with a low Mach number are required aro

A. Babic, L. Miller, M. J. Jarvis, T. J. Turner

Context: X-ray surveys of Active Galactic Nuclei (AGN) indicate `cosmic downsizing&#39;, with the comoving number density of high-luminosity objects peaking at higher redshifts (z about 2) than low-luminosity AGN (z<1). Aims: We test whether downsizing is caused by activity shifting towards low-mass black holes accreting at near-Eddington rates, or by a chan

S. Munier

It has been proposed that the energy evolution of QCD amplitudes in the high-energy regime falls in the universality class of reaction-diffusion processes. We review the arguments for this correspondence, and we explain how it enables one to compute analytically asymptotic features of QCD amplitudes.

Th. Friedrich, E. C. Kim

We prove a lower bound for the first eigenvalue of the Dirac operator on a compact Riemannian spin manifold depending on the scalar curvature as well as a chosen Codazzi tensor. The inequality generalizes the classical estimate from [2].

A. N. Poddubny, E. L. Ivchenko, Yu. E. Lozovik

Transmission, reflection and absorption of electromagnetic radiation and photon dispersion law for 2D photonic crystals with superconducting elements are studied. The calculation of optical properties of photonic crystals is studied by layer-by-layer Korringa-Kohn-Rostoker techniques. The results of numerical calculations performed for an array of supercondu

Jing Zhao, Guo-Hui Ding, Lin Tao, Hong Yu

The architecture of biological networks has been reported to exhibit high level of modularity, and to some extent, topological modules of networks overlap with known functional modules. However, how the modular topology of the molecular network affects the evolution of its member proteins remains unclear. In this work, the functional and evolutionary modular

Robert Delbourgo, Darrel Lashmar

Many structures in nature are invariant under the transformation (p,r)->(br,-p/b), where b is some scale factor. Born&#39;s reciprocity hypothesis affirms that this invariance extends to the entire Hamiltonian and equations of motion. We investigate this idea for atomic physics and galactic motion, where one is basically dealing with a 1/r potential and the

Tomasz Bojdecki, Luis G. Gorostiza, Anna Talarczyk

We extend results on time-rescaled occupation time fluctuation limits of the $(d,α, β)$-branching particle system $(0<α\leq 2, 0<β\leq 1)$ with Poisson initial condition. The earlier results in the homogeneous case (i.e., with Lebesgue initial intensity measure) were obtained for dimensions $d>α/ β$ only, since the particle system becomes locally extinct if

Gustavo Medina-Tanco

The Pierre Auger Collaboration intends to extend the energy range of its southern observatory in Argentina for high quality data from 0.1 to 3 EeV. The extensions, described in accompanying papers, include three additional fluorescence telescopes with a more elevated field of view (HEAT) and a nested surface array with 750 and 433 m spacing respectively and

B. D. Fainberg, M. Jouravlev, A. Nitzan

A theory for light-induced current by strong optical pulses in molecular-tunneling junctions is described. We consider a molecular bridge represented by its highest occupied and lowest unoccupied levels, HOMO and LUMO, respectively. We take into account two types of couplings between the molecule and the metal leads: electron transfer that gives rise to net

John Hauptman

Muons can be identified with high efficiency and purity and reconstructed with high precision is a detector with a dual readout calorimeter and a dual solenoid to return the flux without iron. We shown CERN test beam data for the calorimeter and calculations for the magnetic fields and the track reconstruction. For isolated tracks, the rejection of pions aga

Bruno Goncalves, Yuri N. Obukhov, Ilya L. Shapiro

We consider an exact Foldy-Wouthuysen transformation for the Dirac spinor field on the combined background of a gravitational wave and constant uniform magnetic field. By taking the classical limit of the spinor field Hamiltonian we arrive at the equations of motion for the non-relativistic spinning particle. Two different kinds of the gravitational fields a

K. S. Babu, Thomas W. Kephart, Heinrich Päs

We study orbifold compactifications of the type IIB superstring on AdS_5 x S^5/Gamma, where Gamma is the abelian group Z_8, which can lead to non-SUSY three and four family models based on quartification. In particular, we focus on two models, one fully quartified model and one a model with two trinification families and one quartification family, which redu

K. A. Borovkov, D. C. M. Dickson

We derive a closed-form (infinite series) representation for the distribution of the ruin time for the Sparre Andersen model with exponentially distributed claims. This extends a recent result of Dickson et al. (2005) for such processes with Erlang inter-claim times. We illustrate our result in the cases of gamma and mixed exponential inter-claim time distri

Minoru Fujimoto, Kunihiko Uehara

We consider a variant expression to regularize the Euler product representation of the zeta functions, where we mainly apply to that of the Riemann zeta function in this paper. The regularization itself is identical to that of the zeta function of the summation expression, but the non-use of the Möebius function enable us to confirm a finite behavior of resi

Rich Townsend

To what extent can pulsational instabilities resolve the mass-loss problem of massive stars? How important is pulsation in structuring and modulating the winds of these stars? What role does pulsation play in redistributing angular momentum in massive stars? Although I cannot offer answers to these questions, I hope at the very least to explain how they come

Mark A. Jack, Mario R. Encinosa

A recursive Green&#39;s function method is employed to calculate the density-of-states, transmission function, and current through a 150 layer (3,3) armchair nanotorus (1800 atoms) with laterally attached metallic leads as functions of relative lead angle and magnetic flux. Plateaus in the transmissivity through the torus occur over wide ranges of lead place

Feng Dong, Elena Pierpaoli, James E. Gunn, Risa H. Wechsler

We present a modified adaptive matched filter algorithm designed to identify clusters of galaxies in wide-field imaging surveys such as the Sloan Digital Sky Survey. The cluster-finding technique is fully adaptive to imaging surveys with spectroscopic coverage, multicolor photometric redshifts, no redshift information at all, and any combination of these wit

Chris Meyer, Tyler Rice, Lori Stevens, Bruce A. Schumm

We present recent improvements in the performance of the reconstruction of non-prompt track in the SiD Detector Concept Design, including initial results on the effect of longitudinal segmentation in the SiD tracker. We also describe a generic tracking validation package developed at SCIPP.

C. V. Ciobanu, F. C. Chuang, D. E. Lytle

Although (103) is a stable nominal orientation for both silicon and germanium, experimental observations revealed that in the case of silicon this surface remains disordered on an atomic scale even after careful annealing. We report here a set of low-energy reconstruction models corresponding to $1\times 2$, $2\times 2$, and $1\times 4$ periodicities, and pr

Frederic Zagury

This study establishes that SMC, LMC and Milky Way extinction curves obey the same extinction law which depends on the 2200A bump size and one parameter, and generalizes the Cardelli, Clayton and Mathis (1989) relationship. This suggests that extinction in all three galaxies is of the same nature. The role of linear reddening laws over all the visible/UV wav

Adrian L. Melott

Wang and White (2007) have discussed some problems with N-body simulation methods. These problems are a special case of a more general problem which has been largely unacknowledged for approximately 25 years, and affects results of all dark matter simulations on small scales (the definition of &#39;small&#39; varying with time). Extensive numerical experimen

Thorsten Battefeld

We present a mechanism to create vortices in a plasma via gravitational dragging behind rotating cosmic string loops. The vortical motions create magnetic fields by means of the Harrison-Rees mechanism; the fields are further enhanced through galactic collapse and dynamo amplification. Employing the Velocity dependent One Scale model (VOS) for the string net

David P. Blecher, Upasana Kashyap

We consider a variant of the notion of Morita equivalence appropriate to weak* closed algebras of Hilbert space operators, which we call {\em weak Morita equivalence}. We obtain new variants, appropriate to the dual algebra setting, of the basic theory of strong Morita equivalence, and new nonselfadjoint variants of aspects of Rieffel&#39;s $W^*$-algebraic M

M. A. Jafarizadeh, R. Sufiani, S. Jafarizadeh

Recently, in Refs. \cite{jsj} and \cite{res2}, calculation of effective resistances on distance-regular networks was investigated, where in the first paper, the calculation was based on stratification and Stieltjes function associated with the network, whereas in the latter one a recursive formula for effective resistances was given based on the Christoffel-

M. A. Jafarizadeh, R. Sufiani

By considering distance-regular graphs as spin networks, first we introduce some particular spin Hamiltonians which are extended version of those of Refs.\cite{8,9&#39;&#39;}. Then, by using spectral analysis techniques and algebraic combinatoric structure of distance-regular graphs such as stratification introduced in \cite{obata, js} and Bose-Mesner algebr

Ryan Scranton, Andrew Connolly, Simon Krughoff, Jeremy Brewer

Astronomy began as a visual science, first through careful observations of the sky using either an eyepiece or the naked eye, then on to the preservation of those images with photographic media and finally the digital encoding of that information via CCDs. This last step has enabled astronomy to move into a fully automated era -- where data is recorded, anal

Ketan D. Mulmuley

This article gives conjecturally correct algorithms to construct canonical bases of the irreducible polynomial representations and the matrix coordinate rings of the nonstandard quantum groups in GCT4 and GCT7, and canonical bases of the dually paired nonstandard deformations of the symmetric group algebra therein. These are generalizations of the canonical