September 2006 arXiv papers — page 35

Zarko Mijajlovic, Milos Milosevic, Aleksandar Perovic

In this paper we introduce the notion of the $P$-sequences and apply their properties in studying representability of real numbers. Another application of $P$-sequences we find in generating the Prouhet-Tarry-Escott pairs.

Ioan Bejenaru, Daniela De Silva

We establish that the initial value problem for the quadratic non-linear Schrödinger equation $$ iu_t - Δu = u^2$$ where $u: \R^2 \times \R \to \C$, is locally well-posed in $H^s(\R^2)$ when $s > -1$. The critical exponent for this problem is $s_c=-1$ and previous work in \cite{c1} established local well-posedness for $s > -3/4$.

Athanase Papadopoulos, Marc Troyanov

A weak metric on a set is a function that satisfies the axioms of a metric except the symmetry and the separation axioms. In the present paper we introduced a weak metric, called the Apollonian weak metric, on any subset of a Euclidean space which is either bounded or whose boundary is unbounded. We then relate this weak metric to some familiar metrics such

Stephen Ducret, Marc Troyanov

The aim of this note is to prove that any compact metric space can be made connected at a minimal cost, where the cost is taken to be the one-dimensional Hausdorff measure.

Elemer E Rosinger

A variety of possible extensions of mappings between posets to their Dedekind order completion is presented. One of such extensions has recently been used for solving large classes of nonlinear systems of partial differential equations with possibly associated initial and/or boundary value problems.

Viacheslav V. Nikulin

Let $X$ be an algebraic K3 surface, $v=(r,H,s)$ a primitive isotropic Mukai vector on $X$ and $M_X(v)$ the moduli of sheaves over $X$ with $v$. Let $N(X)$ be Picard lattice of $X$. In math.AG/0309348 and math.AG/0606289, all divisors in moduli of $(X,H)$ (i. e. pairs $H\in N(X)$ with $\rk N(X)=2$) implying $M_X(v)\cong X$ were described. They give some Mukai

Maxim A. Babenko

Consider a $m \times n$ matrix $A$, whose elements are arbitrary integers. Consider, for each square window of size $2 \times 2$, the sum of the corresponding elements of $A$. These sums form a $(m - 1) \times (n-1)$ matrix $S$. Can we efficiently (in polynomial time) restore the original matrix $A$ given $S$? This problem was originally posed by Maurice Niv

Chrysanthos Dellarocas, Ritu Narayan

The emergence of online communities has enabled firms to monitor consumer-generated online word-of-mouth (WOM) in real-time by mining publicly available information from the Internet. A prerequisite for harnessing this new ability is the development of appropriate WOM metrics and the identification of relationships between such metrics and consumer behavior.

Avi Goldfarb, Qiang Lu

This paper makes three contributions: (1) the paper provides a better understanding of online behavior by showing the main drivers of Internet portal choice, (2) the rich data allow for a deeper understanding of brand substitution patterns than previously possible and (3) the paper introduces a wider statistics community to a new data opportunity and a recen

Ziv Ran

We introduce a notion of Jacobi-Bernoulli cohomology associated to a semi-simplicial Lie algebra (SELA). For an algebraic scheme $X$ over $\C$, we construct a tangent SELA $\t_X$ and show that the Jacobi-Bernoulli cohomology of $\t_X$ is related to infinitesimal deformations of $X$.

Maxim A. Babenko

Bidirected graphs (earlier studied by Edmonds, Johnson and, in equivalent terms of skew-symmetric graphs, by Tutte, Goldberg, Karzanov, and others) proved to be a useful unifying language for describing both flow and matching problems. In this paper we extend the notion of ear decomposition to the class of strongly connected bidirected graphs. In particular,

Willem Veys, W. A. Zuniga-Galindo

In this paper we provide a geometric description of the possible poles of the Igusa local zeta function associated to an analytic mapping and a locally constant function, in terms of a log-principalizaton of an ideal naturally attached to the mapping. Typically our new method provides a much shorter list of possible poles compared with the previous methods.

Ngo Bao Chau

We propose a geometric interpretation of the theory of elliptic endoscopy, due to Langlands and Kottwitz, in terms of the Hitchin fibration. As applications, we prove a global analog of a purity conjecture, due to Goresky, Kottwitz and MacPherson. For unitary groups, this global purity statement has been used, in a joint work with G. Laumon, to prove the fun

Ngô Bao Châu

We give a new proof of the base change fundamental lemma for GL_n for certain Hecke functions by comparing the cohomology of two different moduli space of $D$-shtukas. The original proof, due to Clozel and Labesse, make use of the trace formula and of the unit case due to Kottwitz.

Dr. S. Fennell

We give a proof of the inconsistency of PM arithmetic, classical set theory and related systems, incidentally exposing an error in Goedel's own proof of Goedel's Theorems. The inconsistency proof, that formulae of the form R and ~R occur as theorems in the PM-isomorphic system P, proceeds from a reflexive substitution instance of the first axiom of t

T. Banks, B. Fiol, A. Morisse

We describe progress towards constructing a quantum theory of de Sitter space in four dimensions. In particular we indicate how both particle states and Schwarzschild de Sitter black holes can arise as excitations in a theory of a finite number of fermionic oscillators. The results about particle states depend on a conjecture about algebras of Grassmann vari

Tino S. Nyawelo, Stefan Groot Nibbelink

In this talk we study the renormalization of the effective Kaehler potential at one and two loops for general four dimensional (non--renormalizable) N=1 supersymmetric theories described by arbitrary Kaehler potential, superpotential and gauge kinetic function. We consider the Wess-Zumino model as an example.

Margarita Garcia Perez, Antonio Gonzalez-Arroyo

We couple fermion fields in the adjoint representation (gluinos) to the SU(2) gauge field of unit charge calorons defined on R^3 x S_1. We compute corresponding zero-modes of the Dirac equation. These are relevant in semiclassical studies of N=1 Super-symmetric Yang-Mills theory. Our formulas, show that, up to a term proportional to the vector potential, the

Hongbo Cheng

In this paper, the Casimir effect for parallel plates in the presence of one compactified universal extra dimension is reexamined in detail. Having regularized the expressions of Casimir force, we show that the nature of Casimir force is repulsive if the distance between the plates is large enough, which is disagree with the experimental phenomena.

Yuri V. Kovchegov, Heribert Weigert

We study the inclusion of running coupling corrections into the non-linear small-x JIMWLK and BK evolution equations by resumming all powers of alpha_s N_f in the evolution kernels. We demonstrate that the running coupling corrections are included in the JIMWLK/BK evolution kernel by replacing the fixed coupling constant alpha_s in it with alpha_s (1/r_1^2)

Amarjit Soni, Denis A. Suprun

In our previous paper we applied U-spin symmetry to charmless hadronic B+- --> M0 M+- decays for the purpose of precise extraction of the unitarity angle gamma. In this paper we extend our approach to neutral B0 and Bs --> M1 M2 decays. A very important feature of this method is that no assumptions regarding relative sizes of topological decay amplitudes nee

Einan Gardi, Janne Kuokkanen, Kari Rummukainen, Heribert Weigert

A main feature of high-energy scattering in QCD is saturation in the number density of gluons. This phenomenon is described by non-linear evolution equations, JIMWLK and BK, which have been derived at leading logarithmic accuracy. In this paper we generalize this framework to include running coupling corrections to the evolution kernel. We develop a dispersi

Sabrina Casanova

The properties of the non-forward quark-quark correlation function are examined. We derive constraints on the correlation function from the transformation properties of the fundamental fields of QCD occurring in its definition. We further develop a method to construct an ansatz for this correlator. We present the complete leading order set of generalized par

Don Colladay, Patrick McDonald

The explicit one-loop renormalizability of pure Yang-Mills theory with Lorentz violation is demonstrated. The result is consistent with multiplicative renormalization as the required counter terms are consistent with a single re-scaling of the Lorentz-violation parameters. In addition, the resulting beta functions indicate that the CPT-even Lorentz-violating

Daniel Boer, Adrian Dumitru, Arata Hayashigaki

We consider single-inclusive forward pion production in high-energy proton-proton collisions at RHIC energies. A good baseline description of the transverse momentum distributions at high rapidity is obtained within Mueller's dipole formalism with an anomalous dimension incorporating an ``extended geometric scaling'' window between the saturation

T. C. Rogers M. I. Strikman

We apply the dipole formalism that has been developed to describe low-x deep inelastic scattering to the case of ultra-high energy real photons with nucleon and nuclear targets. We hope that there will be future modeling applications in high-energy particle astrophysics. We modify the dipole model of McDermott, Frankfurt, Guzey, and Strikman (MFGS) by fixing

B. Alles, M. D'Elia, M. P. Lombardo

The behaviour of the topological susceptibility in QCD with two colours and 8 flavours of quarks is studied at nonzero temperature on the lattice across the finite density transition. It is shown that its signal drops at a (pseudo-)critical chemical potential mu_c. The Polyakov loop and the chiral condensate undergo their transitions at the same value. Pauli

Andre Sternbeck

We investigate different aspects of lattice QCD in Landau gauge using Monte Carlo simulations. In particular, we focus on the low momentum behavior of gluon and ghost propagators. The gauge group is SU(3). Different systematic effects on the gluon and ghost propagators are studied, e.g. the dependence on the choice of Gribov copies or the influence of dynami

Tommy Burch, Christian Hagen, Andreas Schäfer

We study mesons on the lattice with a special focus on excited states. For that purpose we construct several quark sources with different spatial smearings, including p-waves. These quark sources are then combined with the appropiate Dirac structures to form meson interpolators of definite spin. We use these operators to construct a cross correlation matrix

Xavier Portell

This contribution reports on preliminary measurements on searches for squarks and gluinos at CDF and DØdetectors in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV. The analyses are performed using event topologies with multiple jets and large missing energy in the final state. The mSUGRA scenario and R-parity conservation is assumed. No excess with respect to

Belle Collaboration

We report the observation of the decay $B^{\pm} \to ϕϕK^{\pm}$ and find evidence for $B^{0} \to ϕϕK^{0}$. These results are based on a 414 fb$^{-1}$ data sample that contains $449 \times 10^6$ $B\bar{B}$ pairs, collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ (3.5 on 8 GeV) collider operating at the $Υ(4S)$ resonance. This is the firs

D0 Collaboration, V. Abazov

We measure the dimuon charge asymmetry A in pp(bar) collisions at a center of mass energy sqrt{s} = 1960 GeV. The data was recorded with the D0 detector and corresponds to an integrated luminosity of approximately 1.0 fb-1. Assuming that the asymmetry A is due to asymmetric B^0 <-> B(bar)^0 mixing and decay, we extract the CP-violation parameter of B^0 mixin

Martin Bojowald

Inhomogeneities are introduced in loop quantum cosmology using regular lattice states, with a kinematical arena similar to that in homogeneous models considered earlier. The framework is intended to encapsulate crucial features of background independent quantizations in a setting accessible to explicit calculations of perturbations on a cosmological backgrou

Françoise Gayral, Daniel Kayser, François Lévy

The paper concerns the understanding of plurals in the framework of Artificial Intelligence and emphasizes the role of time. The construction of collection(s) and their evolution across time is often crucial and has to be accounted for. The paper contrasts a &#34;de dicto&#34; collection where the collection can be considered as persisting over these situati

Françoise Gayral, Daniel Kayser, François Lévy

The paper aims at emphasizing that, even relaxed, the hypothesis of compositionality has to face many problems when used for interpreting natural language texts. Rather than fixing these problems within the compositional framework, we believe that a more radical change is necessary, and propose another approach.

Jacob Binia

Expressions for (EPI Shannon type) Divergence-Power Inequalities (DPI) in two cases (time-discrete and band-limited time-continuous) of stationary random processes are given. The new expressions connect the divergence rate of the sum of independent processes, the individual divergence rate of each process, and their power spectral densities. All divergences

Julien M. Hendrickx, Baris Fidan, Changbin Yu, Brian D. O. Anderson

In this paper, we study the construction and transformation of two-dimensional persistent graphs. Persistence is a generalization to directed graphs of the undirected notion of rigidity. In the context of moving autonomous agent formations, persistence characterizes the efficacy of a directed structure of unilateral distances constraints seeking to preserve

Bartlomiej Bartek Blaszczyszyn, Bozidar Radunovic

We consider a hybrid wireless sensor network with regular and transmit-only sensors. The transmit-only sensors do not have receiver circuit, hence are cheaper and less energy consuming, but their transmissions cannot be coordinated. Regular sensors, also called cluster-heads, are responsible for receiving information from transmit-only sensors and forwarding

Frédéric Blanqui

The notion of computability closure has been introduced for proving the termination of the combination of higher-order rewriting and beta-reduction. It is also used for strengthening the higher-order recursive path ordering. In the present paper, we study in more details the relations between the computability closure and the (higher-order) recursive path or

Himanshu Thapliyal, Hamid R. Arabnia, M. B Srinivas

IEEE 754r is the ongoing revision to the IEEE 754 floating point standard and a major enhancement to the standard is the addition of decimal format. Firstly, this paper proposes novel two transistor AND and OR gates. The proposed AND gate has no power supply, thus it can be referred as the Powerless AND gate. Similarly, the proposed two transistor OR gate ha

Cesar Augusto Sangaletti Tercariol, Felipe de Mouta Kiipper, Alexandre Souto Martinez

Consider that the coordinates of $N$ points are randomly generated along the edges of a $d$-dimensional hypercube (random point problem). The probability that an arbitrary point is the $m$th nearest neighbor to its own $n$th nearest neighbor (Cox probabilities) plays an important role in spatial statistics. Also, it has been useful in the description of phys

A. L. Efros

The problem of the principal existence of the perfect lens and superlensing is discussed. We have demonstrated that in the case of the virtual focus the idea of perfect lens based upon amplification of evanescent waves as proposed by Pendry is perfectly right unlike the case of the real foci. We think that some experimental results claiming superlensing can

P. R. Broussard

The electrical resistivity of La$_{1-x}$Ca$_{x}$MnO$_{3}$ thin films grown on (001) NdGaO$_{3}$ and (100) SrTiO$_{3}$ substrates by off-axis sputtering has been studied as a function of the Calcium doping level. The samples have very narrow rocking curves and excellent in plane registry with the substrate. A strong correlation between the peak resistance tem

C. A. Dartora, G. G. Cabrera

We study the dynamics of molecular nanomagnets through a fully quantum mechanical model describing high-spin and high-anisotropy magnetic molecules subjected to a time-dependent magnetic field along the quantization axis, which continuously inverts the population of spin states. Crystals of molecular nanomagnets placed inside a resonant cavity interact with

David Lancaster

A recently formulated statistical mechanics method is used to study the phase transition occurring in a generalisation of the Traveling Salesman Problem (TSP) known as the centred TSP. The method shows that the problem has clear signs of a crossover, but is only able to access (unscaled) finite temperatures above the transition point. The solution of the pro

Sangita Bose, Pratap Raychaudhuri, Rajarshi Banerjee, Pushan Ayyub

We show that the upper critical field in nanometer-sized Nb particles is governed by the changes in the effective Ginzburg-Landau coherence length occurring due to two competing factors: (i) the decrease in the grain size and consequent increase of disorder, and (ii) the effective decrease in the density of states at the Fermi level due to the formation of a

Hang Wong, Zhi-De Chen

The influence of dissipation on quantum tunneling in the spin-boson model with a sub-Ohmic bath is studied by a variational calculation. By examining the evolution of solutions of the variational equation with the coupling strength near the phase boundary, we are able to present a scenario of discontinuous transition in sub-Ohmic dissipation case in accord w

Sangita Bose, Rajarshi Banerjee, Arda Genc, Pratap Raychaudhuri

With a reduction in the average grain size in nanostructured films of elemental Nb, we observe a systematic crossover from metallic to weakly-insulating behavior. An analysis of the temperature dependence of the resistivity in the insulating phase clearly indicates the existence of two distinct activation energies corresponding to inter-granular and intra-gr

N. B. Perkins, J. R. Iglesias, M. D. Nunez-Regueiro, B. Coqblin

Coexistence between ferromagnetic order and Kondo behavior has been observed in some uranium compounds. The underscreened Kondo lattice model can provide a possible description of this coexistence. Here we present a model of a lattice of S=1 spins coupled to the conduction electrons through an intra-site exchange interaction $J_{K}$ and an inter-site ferroma

A. N. Vamivakas, Y. Yin, A. G. Walsh, M. S. Unlu

A mass and spring model is used to calculate the phonon mode dispersion for single wall carbon nanotubes (SWNTs) of arbitrary chirality. The calculated dispersions are used to determine the chirality dependence of the radial breathing phonon mode (RBM) density. Van Hove singularities, usually discussed in the context of the single particle electronic excitat

Shahab Zorriasatein, Kavita Joshi, D. G. Kanhere

With the advances in miniaturization, understanding and controlling properties of significant technological systems like silicon in nano regime assumes considerable importance. It turns out that small silicon clusters in the size range of 15-20 atoms are unstable upon heating and in fact fragment in the temperature range of 1200 K to 1500 K. In the present w

F. D&#39;Orazio, F. Lucari, M. Passacantando, L. Ottaviano

Magneto-optical Kerr effect hysteresis loops at various wavelengths in the visible/near-infrared range have been used to characterize the magnetic properties of alloys obtained by implanting Mn ions at fixed energy in a Ge matrix. The details of the hysteresis loops reveal the presence of multiple magnetic contributions. They may be attributed to the inhomog

S. Takahashi, S. Maekawa

Spin Hall effect in a nonlocal spin-injection device is theoretically studied. Using a nonlocal spin-injection technique, a pure spin current is created in a nonmagnetic metal (N). The spin current flowing in N is deflected by spin-orbit scattering to induce the Hall current in the transverse direction and accumulate charge at the edges of N, yielding the sp

M. V. Costache, S. M. Watts, M. Sladkov, C. H. van der Wal

We demonstrate on-chip resonant driving of large cone-angle magnetization precession of an individual nanoscale permalloy element. Strong driving is realized by locating the element in close proximity to the shorted end of a coplanar strip waveguide, which generates a microwave magnetic field. We used a microwave frequency modulation method to accurately mea

M. J. van Setten, V. A. Popa, G. A. de Wijs, G. Brocks

We study the electronic structures and dielectric functions of the simple hydrides LiH, NaH, MgH2 and AlH3, and the complex hydrides Li3AlH6, Na3AlH6, LiAlH4, NaAlH4 and Mg(AlH4)2, using first principles density functional theory and GW calculations. All these compounds are large gap insulators with GW single particle band gaps varying from 3.5 eV in AlH3 to

E. Taylor, A. Griffin, N. Fukushima, Y. Ohashi

We derive an expression for the superfluid density of a uniform two-component Fermi gas through the BCS-BEC crossover in terms of the thermodynamic potential in the presence of an imposed superfluid flow. Treating the pairing fluctuations in a Gaussian approximation following the approach of Nozières and Schmitt-Rink, we use this definition of $ρ_s$ to obtai

Nobuya Maeshima, Kenji Yonemitsu

Dynamical properties of photoexcited states are theoretically studied in a one-dimensional Mott insulator dimerized by the spin-Peierls instability. Numerical calculations combined with a perturbative analysis have revealed that the lowest photoexcited state without nearest-neighbor interaction corresponds to an interdimer charge transfer excitation that bel

J. T. Padding, A. A. Louis

We describe in detail how to implement a coarse-grained hybrid Molecular Dynamics and Stochastic Rotation Dynamics simulation technique that captures the combined effects of Brownian and hydrodynamic forces in colloidal suspensions. The importance of carefully tuning the simulation parameters to correctly resolve the multiple time and length-scales of this p

M. Pletyukhov, V. Gritsev, N. Pauget

We study the tunneling current through a mesoscopic two-terminal ring with spin-orbit coupling, which is threaded by a magnetic flux. The electron-electron interaction in the ring is described in terms of a Tomonaga-Luttinger model which also allows us to account for a capacitive coupling between the ring and the gate electrode. In the regime of weak tunneli

T. Hand, J. Kroha, H. Monien

We analyze the Kondo effect of a magnetic impurity attached to an ultrasmall metallic wire using the density matrix renormalization group. The spatial spin correlation function and the impurity spectral density are computed for system sizes of up to L=511 sites, covering the crossover from $L<\ell_K$ to $L > \ell_K$, with $\ell_K$ the spin screening length.

M. Pletyukhov, V. Gritsev

We study screening properties of the two-dimensional electron gas with Rashba spin-orbit coupling. Calculating the dielectric function within the random phase approximation, we describe the new features of screening induced by spin-orbit coupling, which are the extension of the region of particle-hole excitations and the spin-orbit-induced suppression of col

San-Huang Ke, Harold U. Baranger, Weitao Yang

Bridging the difference in atomic structure between experiments and theoretical calculations and exploring quantum confinement effects in thin electrodes (leads) are both important issues in molecular electronics. To address these issues, we report here, by using Au-benzenedithiol-Au as a model system, systematic investigations of different models for the le

Sean N. Raymond, Avi M. Mandell, Steinn Sigurdsson

Close-in giant planets (e.g. ``Hot Jupiters&#39;&#39;) are thought to form far from their host stars and migrate inward, through the terrestrial planet zone, via torques with a massive gaseous disk. Here we simulate terrestrial planet growth during and after giant planet migration. Several-Earth mass planets also form interior to the migrating Jovian planet,

A. A. Suchkov, R. J. Hanisch, W. Voges, T. M. Heckman

We present a sample of 1744 type 1 active galactic nuclei (AGNs) from the Sloan Digital Sky Survey (SDSS DR4) spectroscopic catalog with X-ray counterparts in the White-Giommi-Angelini Catalog (WGACAT) of ROSAT PSPC pointed observations. Of 1744 X-ray sources, 1410 (80.9%) are new AGN identifications. Of 4574 SDSS DR4 AGNs for which we found radio matches in

Aaron J. Romanowsky

I review the field of globular cluster system (GCS) kinematics, including a brief primer on observational methods. The kinematical structures of spiral galaxy GCSs so far appear to be broadly similar. The inferred rotation and mass profiles of elliptical galaxy halos exhibit a diversity of behaviors, requiring more systematic observational and theoretical st

E. I. Vorobyov, Ch. Theis

We present the Boltzmann moment equation approach for the dynamics of stars (BEADS-2D), which is a finite-difference Eulerian numerical code designed for the modelling of anisotropic and non-axisymmetric flat stellar disks. The BEADS-2D code solves the Boltzmann moment equations up to second order in the thin-disk approximation. This allows us to obtain the

Gurtina Besla, Yanqin Wu

Narrow dust rings observed around some young stars (e.g., HR 4796A) need to be confined. We present a possible explanation for the formation and confinement of such rings in optically thin circumstellar disks, without invoking shepherding planets. If an enhancement of dust grains (e.g., due to a catastrophic collision) occurs somewhere in the disk, photoelec

Koji Mukai, Manabu Ishida, Caroline Kilbourne, Hideyuki Mori

CH Cygni is a symbiotic star consisting of an M giant and an accreting white dwarf, which is known to be a highly variable X-ray source with a complex, two-component, spectra. Here we report on two Suzaku observations of CH Cyg, taken in 2006 January and May, during which the system was seen to be in a soft X-ray bright, hard X-ray faint state. Based on the

Uma P. Vijh, Adolf N. Witt, Donald G. York, Vikram V. Dwarkadas

We present narrow-band images of the Red Rectangle (RR) nebula which reveal the distinct morphologies of this intriguing nebula in different optical emission bands. The morphology of the RR nebula in blue luminescence (BL) and extended red emission (ERE) are almost mutually exclusive. We also present the optical detection of the circum-binary disk of the RR

Carlos F. Sopuerta

This is a brief report on time-domain numerical simulations of extreme-mass-ratio binaries based on finite element methods. We discuss a new technique for solving the perturbative equations describing a point-like object orbiting a non-rotating massive black hole and the prospects of using it for the evaluation of the gravitational self-force responsible of

John Magorrian

When faced with the task of constraining a galaxy&#39;s potential given limited stellar kinematical information, what is the best way of treating the galaxy&#39;s unknown distribution function (DF)? Using the example of estimating black hole (BH) masses, I argue that the correct approach is to consider all possible DFs for each trial potential, marginalizing

Alan W. McConnachie, Nobuo Arimoto, Mike Irwin, Eline Tolstoy

We use Subaru Suprime-Cam and VLT FORS1 photometry of the dwarf galaxy DDO210 to study the global stellar content and structural properties of a transition-type galaxy (with properties intermediate between dwarf irregular and dwarf spheroidal systems). This galaxy is sufficiently isolated that tidal interactions are not likely to have affected its evolution

Cristina M. Oliveira, Guillaume Hebrard

We use new FUSE data to determine the column densities of interstellar DI, NI, OI, FeII, and H2 along the HD41161 and HD53975 sightlines. Together with N(HI) from the literature (derived from Copernicus and IUE data) we derive D/H, N/H, and O/H ratios. These high column density sightlines have both log H(HI)>21.00 and allow us to probe gas up to 1300 pc. In

Karl E. Haisch, Mary Barsony, Michael E. Ressler, Thomas P. Greene

We have obtained new mid-infrared observations of 65 Class I/Flat-Spectrum (F.S.) objects in the Perseus, Taurus, Chamaeleon I/II, Rho Ophiuchi, and Serpens dark clouds. We detected 45/48 (94%) of the single sources, 16/16 (100%) of the primary components, and 12/16 (75%) of the secondary/triple components of the binary/multiple objects surveyed. The composi

Peter W. J. L. Brand

Much emission from star forming regions is from shock-excited gas. Shocks in molecular clouds are still not fully understood, as magnetic fields, dust and chemistry all play significant roles. I review the history, physics and current work in understanding these shocks, and in their possible use as diagnostics of local conditions.

Praveen Kundurthy, Michael R. Meyer, Massimo Robberto, Steven V. W. Beckwith

We present mid-IR N-band $(λ_{eff} = 10.2\micron)$ photometry of a carefully selected sample of T Tauri stars thought to be single from the Taurus-Auriga molecular cloud. Infrared excesses in these stars are generally attributed to circumstellar dust-disks. Combining observations at 2.16$\micron$ (K$_{s}$-band) and 10.2$\micron$ (N-band) we probe a region in

A. Tamanai, H. Mutschke, J. Blum, G. Meeus

The profile of the silicate 10 $μ$m IR band contains important information about the evolutional stage of dust in circumstellar environments and the possible ongoing process of planetesimal formation. In order to extract this information, the observed band profiles are compared with calculated or laboratory-measured absorption cross sections of amorphous and

D. Maino, S. Donzelli, A. J. Banday, F. Stivoli

We present an application of the fast Independent Component Analysis (FastICA) to the WMAP 3yr data with the goal of extracting the CMB signal. We evaluate the confidence of our results by means of Monte Carlo simulations including CMB, foreground contaminations and instrumental noise specific of each WMAP frequency band. We perform a complete analysis invol

B. Fuchs, D. Breitschwerdt, M. A. de Avillez, C. Dettbarn

We present a new unbiased search and analysis of all B stars in the solar neighbourhood (within a volume of 400 pc diameter) using the Arivel data base to track down the remains of the OB associations, which hosted the supernovae responsible for the Local Bubble in the interstellar gas. We find after careful dereddening and by comparison with theoretical iso

D. Koutroumpa, R. Lallement, V. Kharchenko, A. Dalgarno

We study the EUV/soft X-ray emission generated by charge transfer between solar wind heavy ions and interstellar H and He neutral atoms in the inner Heliosphere. We present heliospheric maps and spectra for stationary solar wind, depending on solar cycle phase, solar wind anisotropies and composition, line of sight direction and observer position. A time-dep

Ya. V. Pavlenko, J. Th. van Loon, A. Evans, M. T. Rushton

We present the results of modelling the 0.45--1 micron spectral energy distribution of V838 Mon for 2002 November. Synthetic spectra were calculated using the NextGen model atmospheres of Hauschildt et al. (1999), which incorporate line lists for H2O, TiO, CrH, FeH, CO, and MgH, as well as the VALD atomic line list. Fits to the observed spectra show that, in

Jadwiga Daszynska-Daszkiewicz, Andrzej Pigulski

We present the analysis of simultaneous multicolour $uvyI_{\rm C}$ photometry and low-resolution spectroscopy for the rapidly rotating $β$ Cephei star SY Equ. From the photometric time series, we confirm the dominant pulsation frequency, $f_1$ = 6.029 d$^{-1}$, and we find an evidence for two additional modes. In spectroscopy, the highest peak occurs at $f_{

M. A. Voronkov, K. J. Brooks, A. M. Sobolev, S. P. Ellingsen

The Australia Telescope Compact Array (ATCA) has been used to image class I methanol masers at 9.9, 25 (a series from J=2 to J=9), 84, 95 and 104 GHz located in the vicinity of IRAS 16547-4247 (G343.12-0.06), a luminous young stellar object known to harbour a radio jet. The detected maser emission consists of a cluster of 6 spots spread over an area of 30 ar

L. Sidoli, A. Paizis, A. Bazzano, S. Mereghetti

The X-ray burster 4U1850-087, located in the Galactic globular cluster NGC6712, is an ultracompact binary (orbital period~21 min),likely harbouring a degenerate companion.The source has been observed at soft gamma-rays several times with the INTEGRAL satellite,during the monitoring of the Galactic plane, with an unprecedented exposure time.We analysed all av

John Lee Grenfell, Barbara Stracke, Beate Patzer, Ruth Titz

We propose that the photochemical smog mechanism produced substantial ozone (O3) in the troposphere during the Proterozoic, which contributed to ultraviolet (UV) radiation shielding hence favoured the establishment of life. The smog mechanism is well-established and is associated with pollution hazes which sometimes cover modern cities. The mechanism proceed

Antonio L. Maroto

If dark energy can be described as a perfect fluid, then, apart from its equation of state relating energy density and pressure, we should also especify the corresponding rest frame. Since dark energy is typically decoupled from the rest of components of the universe, in principle such a frame could be different from that of matter and radiation. In this wor

Katsuji Koyama, Yoshiaki Hyodo, Tatsuya Inui

We report the diffuse X-ray emissions from the Sgr A and B regions observed with Suzaku. From the Sgr A region, we found many K-shell transition lines of iron and nickel. The brightest are K alpha lines from FeI, FeXXV and FeXXVI at 6.4 keV, 6.7 keV and 6.9 keV. In addition, K alpha lines of NiI and NiXXVII, K beta of FeI, FeXXV and FeXXVI, and K gamma of Fe

Ruth Durrer

I describe the imprint of primordial magnetic fields on the CMB. I show that these are observable only if the field amplitude is of the order of $B\gsim 10^{-9}G$ on Mpc scale. I further argue that such fields are strongly constrained by the stochastic background of gravity waves which they produce. Primordial magnetic fields, which are strong enough to be s

Katsuji Koyama, Yoshiaki Hyodo, Tatsuya Inui, Hiroshi Nakajima

We have observed the diffuse X-ray emission from the Galactic center (GC) using the X-ray Imaging Spectrometer (XIS) on Suzaku. The high-energy resolution and the low-background orbit provide excellent spectra of the GC diffuse X-rays (GCDX). The XIS found many emission lines in the GCDX near the energy of K-shell transitions of iron and nickel. The most pro

H. Nishimura, K. Hattori, H. Kubo, T. Tanimori

We have developed a position-sensitive scintillation camera with a large area absorber for use as an advanced Compton gamma-ray camera. At first we tested GSO(Ce) crystals. We compared light output from the GSO(Ce) crystals under various conditions: the method of surface polishing, the concentration of Ce, and co-doping Zr. As a result, we chose the GSO(Ce)

Norman Murray, Crystal L. Martin, Eliot Quataert, Todd A. Thompson

Roughly 80% of Ultraluminous Infrared Galaxies (ULIRGs) show blue shifted absorption in the resonance lines of neutral sodium, indicating that cool winds are common in such objects, as shown by Rupke et al and by Martin. The neutral sodium (NaI) columns indicated by these absorption lines are ~ 10^{13}-3x10^{14}/cm^2, while the bolometric luminosity varies b

Chao-Wei Tsai, Jean L. Turner, Sara C. Beck, Lucian P. Crosthwaite

We report subarcsecond-resolution VLA imaging of four nearby spiral galaxies: IC 342, Maffei II, NGC 2903, and NGC 6946. In each galaxy, compact radio continuum sources are identified in the central ~ 15&#34; x 15&#34; region. These compact sources are responsible for 20 - 30 % of the total emission from the central kpc of the host galaxies at 2 cm, but only

Benjamin F. Williams, Robin Ciardullo, Patrick R. Durrell, John J. Feldmeier

We report the discovery of 4 candidate intracluster globular clusters (IGCs) in a single deep HST ACS field of the Virgo Cluster. We show that each cluster is roughly spherical, has a magnitude near the peak of the Virgo globular cluster luminosity function, has a radial profile that is best-fit by a King model, and is surrounded by an excess of point source

Chao-Wei Tsai, Jean L. Turner, Sara C. Beck, Lucian P. Crosthwaite

We report subarcsecond-resolution VLA imaging of the centers of four nearby spiral galaxies: IC 342, Maffei II, NGC 2903, and NGC 6946. In each galaxy, 7 - 12 compact radio continuum sources were identified within the central 15&#34; x 15&#34;. Slightly over half of the compact sources appear to be HII regions with flat or positive spectral indices (alpha >~

Wenxian Zhang, V. V. Dobrovitski, K. A. Al-Hassanieh, E. Dagotto

We investigate in detail, using both analytical and numerical tools, the decoherence of electron spins in quantum dots (QDs) coupled to a bath of nuclear spins in magnetic fields or with various initial bath polarizations, focusing on the longitudinal relaxation in low and moderate field/polarization regimes. An increase of the initial polarization of nuclea

James Wirth, Jim Stasheff

For locally homotopy trivial fibrations, one can define transition functions $$ g\dab : U\da\cap U\db \to H = H(F)$$ where $H$ is the monoid of homotopy equivalences of $F$ to itself but, instead of the cocycle condition, one obtains only that $g\dab g\dbgam$ is homotopic to $g\dagam$ as a map of $U\da\cap U\db\cap U\dgam$ into $H$. Moreover on multiple inte

Evan Scannapieco

I review the physical properties of pair-production supernovae (PPSNe) as well as the prospects for them to be constrained observationally. In very massive (140-260 solar mass) stars, much of the pressure support comes from the radiation field, meaning that they are loosely bound, with an adiabatic coefficient that is close to the minimum stable value. Near

Dah-Wei Chiou

The comprehensive formulation for loop quantum cosmology in the spatially flat, isotropic model was recently constructed. In this paper, the methods are extended to the anisotropic Bianchi I cosmology. Both the precursor and the improved strategies are applied and the expected results are established: (i) the scalar field again serves as an internal clock an

Justin Trice, Dennis Thomas, Christopher Favazza, Radhakrishna Sureshkumar

Hydrodynamic pattern formation (PF) and dewetting resulting from pulsed laser induced melting of nanoscopic metal films have been used to create spatially ordered metal nanoparticle arrays with monomodal size distribution on SiO_{\text{2}}/Si substrates. PF was investigated for film thickness h\leq7 nm < laser absorption depth \sim11 nm and different sets of

Erick J. Weinberg, Piljin Yi

We review the properties of BPS, or supersymmetric, magnetic monopoles, with an emphasis on their low-energy dynamics and their classical and quantum bound states. After an overview of magnetic monopoles, we discuss the BPS limit and its relation to supersymmetry. We then discuss the properties and construction of multimonopole solutions with a single nontri