June 2004 arXiv papers — page 3

Aicha Hachemi

We prove a local limit theorem for the Euclidian algorithms ; standard, centred and odd, with any cost function of moderate growth.

Laurent Berger

The goal of this article is to show that the following two categories are equivalent (1) the category of filtered (phi,N,G_K)-modules (2) the category of (phi,Gamma_K)-modules over the Robba ring such that the Lie algebra of Gamma_K acts locally trivially. Furthermore, we show that under this equivalence, the admissible filtered (phi,N,G_K)-modules correspon

L. A. Khodarinova, J. N. Webb

The standard iterated prisoner's dilemma is an unrealistic model of social behaviour because it forces individuals to participate in the interaction. We analyse a model in which players have the option of ending their association. If the payoff for living alone is neither too high nor too low then the potential for cooperative behaviour is enhanced. For

Alberto Alzati, Francesco Russo

We construct explicit examples of elementary extremal contractions, both birational and of fiber type, from smooth projective n-dimensional varieties, n\geq 4, onto smooth projective varieties, arising from classical projective geometry and defined over sufficiently small fields, not necessarily algebraically closed. The examples considered come from particu

Francesco Delli Priscoli, Lorenzo Marconi, Alberto Isidori

This paper shows how the theory of nonlinear adaptive observers can be effectively used in the design of internal models for nonlinear output regulation. The theory substantially enhances the existing results in the context of {\em adaptive} output regulation, by allowing for not necessarily stable zero dynamics of the controlled plant and by weakening the s

E. E. Rosinger

As a significant strengthening of properties of earlier algebras of generalized functions, here are presented classes of such algebras which can deal with dense singularities. In fact, the cardinal of the set of singular points can be larger than that of the nonsingular points. This large class of singularities allows the solution of large classes of smooth

Yves Felix, Jean-Claude Thomas, Micheline Vigue-Poirrier

We use the computational power of rational homotopy theory to provide an explicit cochain model for the loop product and the string bracket of a 1-connected closed manifold M. We prove that the loop homology of M is isomorphic to the Hochschild cohomology of the commutative graded algebra A_{PL}(M) with coefficients in itself. Some explicit computations of t

Ja A Jeong, Gi Hyun Park

Let A_E be the canonical AF subalgebra of a graph C*-algebra C*(E) associated with a locally finite directed graph E. For Brown-Voiculescu's topological entropy ht(Φ_E) of the canonical completely positive map Φ_E on C*(E), ht(Φ_E)=ht(Φ_E|_{A_E})=h_l(E)=h_b(E) is known to hold for a finite graph E, where h_l(E) is the loop entropy of Gurevic and h_b(E) i

Michael E. Hoffman

Multiple harmonic sums appear in the perturbative computation of various quantities of interest in quantum field theory. In this article we introduce a class of Hopf algebras that describe the structure of such sums, and develop some of their properties that can be exploited in calculations.

Vladimir Tolstykh

We say that a group $G$ has Bergman's property (the property of universality of finite width) if for every generating set $X$ of $G$ with $X=X^{-1}$ we have that $G=X^k$ for some natural number $k.$ The property is named after George Bergman who have proved recently that the infinite symmetric groups are groups of universally finite width. The first exam

Roger Mansuy, Marc Yor

Relations between so-called harness processes and initial enlargements of the filtration of a Levy process with its positions at fixed times are investigated.

Hossein Namazi

We show that if $M$ is a closed three manifold with a Heegaard splitting with sufficiently big "handlebody distance" then the subgroup of the mapping class group of the Heegaard surface, which extend to both handlebodies is finite. As a corollary, this implies that under the same hypothesis, the mapping class group of $M$ is finite.

Chiara Frosini

Let Delta^{n} be the unit polydisc in C^{n} and let f be a holomorphic self map of Delta^{n}. When n=1, it is well known, by Schwarz's lemma, that f has at most one fixed point in the unit disc. If no such point exists then f has a unique boundary point, call it x, such that every horocycle E(x,R) of center x and radius R>0 is sent into itself by f. This

Bertrand Toen, Gabriele Vezzosi

We develop homotopical algebraic geometry (see math.AG/0207028) in the special context where the base symmetric monoidal model category is the category S of spectra, i.e. what might be called, after Waldhausen, ``brave new algebraic geometry''. We discuss various model topologies on the model category of commutative algebras in S, the associated theo

J. Kluson

In this paper we will study the ground states of the toy model of 2D closed string tachyon effective action. We will firstly construct the classical solutions of the tachyon effective action that do not induce backreaction on metric and dilaton. Then we will study the quantum mechanics of the zero mode of the tachyon field. We will find family of vacuum stat

Pedro F. Gonzalez-Diaz, Jose A. Jimenez-Madrid

Primordial inflation is regarded to be driven by a phantom field which is here implemented as a scalar field satisfying an equation of state $p=ωρ$, with $ω<-1$. Being even aggravated by the weird properties of phantom energy, this will pose a serious problem with the exit from the inflationary phase. We argue however in favor of the speculation that a smoot

Michael R. Douglas

We discuss the question of what type and scale of supersymmetry breaking might be statistically favored among vacua of string/M theory, building on comments in Denef and Douglas, hep-th/0404116.

H. Boos, M. Jimbo, T. Miwa, F. Smirnov

A new recursion formula is presented for the correlation functions of the integrable spin 1/2 XXX chain with inhomogeneity. It relates the correlators involving n consecutive lattice sites to those with n-1 and n-2 sites. In a series of papers by V. Korepin and two of the present authors, it was discovered that the correlators have a certain specific structu

Jerzy Szwed

The &#34;square root&#34; of the Dirac operator derived on the superspace is used to construct supersymmetric field equations. In addition to the recently found solution - a vector supermultiplet I demonstrate how a chiral supermultiplet follows as the solution. Both vector and chiral supermultiplets are shown to obey appropriate (massless) equations of moti

R. J. Porter, T. A. Trainor

We report measurements of large-scale two-particle correlations for 200 GeV p-p collisions on momentum components transverse rapidity $y_t$ (pion mass assigned), pseudorapidity $η$ and azimuth angle $ϕ$. In both transverse $y_t \otimes y_t$ and axial $(η\otimesη,ϕ\otimesϕ) $ two-particle subspaces we observe two components of correlation structure (soft and

David H. Lyth, Yeinzon Rodriguez, Carlos Quimbay

We show how the mechanism recently proposed by Alexander, Peskin, and Sheikh-Jabbari, in which the observed cosmic matter-antimatter asymmetry comes from the contribution of the cosmological tensor perturbations to the gravitational anomaly in the Standard Model, does not work. This holds when taking into account the commutation relations for the creation-an

T. Barnes

This paper gives a short summary of some of the aspects of charmonium which can be addressed at BES and CLEO-c and other $e^+e^-$ facilities. These topics include the spectroscopy of charmonium states, radiative transitions, $e^+e^-$ widths, two-photon widths, hadron loop effects and open-flavor strong decays.

Patricia Ball

Do you know that CP violation is intrinsically linked to the scalar sector of the Standard Model and its extensions? If yes, you need read no further - if no, you may turn over the titlepage and start reading now.

S. J. Brodsky, V. A. Franke, J. R. Hiller, G. McCartor

In principle, the complete spectrum and bound-state wave functions of a quantum field theory can be determined by finding the eigenvalues and eigensolutions of its light-cone Hamiltonian. One of the challenges in obtaining nonperturbative solutions for gauge theories such as QCD using light-cone Hamiltonian methods is to renormalize the theory while preservi

M. Duhrssen, S. Heinemeyer, H. Logan, D. Rainwater

We show how LHC Higgs boson production and decay data can be used to extract gauge and fermion couplings of Higgs bosons. We show that very mild theoretical assumptions, which are valid in general multi-Higgs doublet models, are sufficient to allow the extraction of absolute values for the couplings rather than just ratios of the couplings. For Higgs masses

K. J. Eskola, H. Honkanen, C. A. Salgado, U. A. Wiedemann

We study the suppression of high-pT hadron spectra in nuclear collisions, supplementing the perturbative QCD factorized formalism with radiative parton energy loss. We find that the nuclear modification factor which quantifies the degree of suppression, is almost pT-independent both for RHIC (in agreement with data) and for the LHC. This is a consequence of

Stefan Weinzierl

I discuss methods for the cancellation of infrared divergences at NNLO.

T. Goto, K. Kawagoe, M. M. Nojiri

In supersymmetric theory, the sfermion-fermion-gaugino interactions conserve the chirality of (s)fermions. The effect appears as the charge asymmetry in $m(jl)$ distributions at the CERN Large Hadron Collider where jets and leptons arise from the cascade decay $\tilde{q} \to q \tildeχ^0_2 \to ql\tilde{l}$. Furthermore, the decay branching ratios and the char

Leonard Susskind

This paper was withdrawn by the author.

Marc Verderi

We present measurements related to the CKM angle beta from BABAR based on 82 or ~115 fb-1 data samples collected at the PEP-II e+e- asymmetric B Factory collider. A new method allowing to measure the sign of cos(2.beta) with B0->J/Psi&#34;K*0&#34; events is explained and related results reported. Recent CP measurements in the penguin dominated modes B0->phi

M. Bashkanov, CELSIUS-WASA collaboration

The $pp \to ppγγ$ reaction has been measured at CELSIUS using the WASA $4π$-detector with hydrogen pellet target. At $T_p = 1.20$ and 1.36 GeV, where most of the statistics has been accumulated, the $γγ$ invariant mass spectrum exhibits a narrow structure around the $ππ$ threshold, which possibly may be associated with two-photon radiation of $π^+π^-$ loops

By CDF, D0 collaborations

The Fermilab Tevatron collider experiments, CDF and \dz, have collected over 200 ${\rm pb}^{-1}$ of data at $\sqrt{s}=1.96$ TeV since March 2002 (RunII). Both experiments have investigated physics beyond the Standard Model; this paper reviews some of the recent results on the searches for new phenomena, concentrating on Z&#39;, extra dimensions, excited elec

Josef Pochodzalla

Recent evidence for pentaquark baryons is critically reviewed in the light of new high statistics data. The search of the WA89 experiment for the $Ξ^{--}(1860)$ is presented in detail and consequences of its non-observations are discussed.

Luis Lehner, David Neilsen, Oscar Reula, Manuel Tiglio

The energy method can be used to identify well-posed initial boundary value problems for quasi-linear, symmetric hyperbolic partial differential equations with maximally dissipative boundary conditions. A similar analysis of the discrete system can be used to construct stable finite difference equations for these problems at the linear level. In this paper w

Jan Van den Bussche, Dirk Van Gucht, Stijn Vansummeren

Two natural decision problems regarding the XML query language XQuery are well-definedness and semantic type-checking. We study these problems in the setting of a relational fragment of XQuery. We show that well-definedness and semantic type-checking are undecidable, even in the positive-existential case. Nevertheless, for a ``pure&#39;&#39; variant of XQuer

Maximillian Dornseif, Felix C. Gaertner, Thorsten Holz

Electronic bait (honeypots) are network resources whose value consists of being attacked and compromised. These are often computers which do not have a task in the network, but are otherwise indestinguishable from regular computers. Such bait systems could be interconnected (honeynets). These honeynets are equipped with special software, facilitating forensi

V. Podzorov, V. M. Pudalov, M. E. Gershenson

We report on observation of a light-induced switching of the conductance in the back-gated organic field-effect transistors (OFETs) with built-in conduction channel. In the studied devices, the built-in channel is formed owing to the self-sensitized photo-oxidation of rubrene surface. In the dark, the back gate controls the charge injection from metal contac

P. G. Kevrekidis, B. A. Malomed, D. J. Frantzeskakis, R. Carretero-González

In a benchmark dynamical-lattice model in three dimensions, the discrete nonlinear Schr{ö}dinger equation, we find discrete vortex solitons with various values of the topological charge $S$. Stability regions for the vortices with $S=0,1,3$ are investigated. The S=2 vortex is unstable, spontaneously rearranging into a stable one with S=3. In a two-component

P. G. Kevrekidis, R. Carretero-González, G. Theocharis, D. J. Frantzeskakis

We investigate the dynamics of vortices in repulsive Bose-Einstein condensates in the presence of an optical lattice (OL) and a parabolic magnetic trap. The dynamics is sensitive to the phase of the OL potential relative to the magnetic trap, and depends less on the OL strength. For the cosinusoidal OL potential, a local minimum is generated at the trap&#39;

Sitabhra Sinha, S. Raghavendra

Numerical data for all movies released in theaters in the USA during the period 1997-2003 are examined for the distribution of their popularity in terms of (i) the number of weeks they spent in the Top 60 according to the weekend earnings, and (ii) the box-office gross during the opening week, as well as, the total duration for which they were shown in theat

Gabriel Bester, J. Shumway, Alex Zunger

We present results of correlated pseudopotential calculations of an exciton in a pair of vertically stacked InGaAs/GaAs dots. Competing effects of strain, geometry, and band mixing lead to many unexpected features missing in contemporary models. The first four excitonic states are all optically active at small interdot separation, due to the broken symmetry

J. S. Xia, W. Pan, C. L. Vincente, E. D. Adams

At a very low temperature of 9mK, electrons in the 2nd Landau level of an extremely high mobility two-dimensional electron system exhibit a very complex electronic behavior. With varying filling factor, quantum liquids of different origins compete with several insulating phases leading to an irregular pattern in the transport parameters. We observe a fully d

M. Venkatesan, C. B. Fitzgerald, J. G. Lunney, J. M. D. Coey

Room-temperature ferromagnetism is observed in (110) oriented ZnO films containing 5 at % of Sc, Ti, V, Fe, Co or Ni, but not Cr, Mn or Cu ions. There are large moments, 1.9 and 0.5 muB/atom for Co- and Ti-substituted oxides, respectively. Sc-substituted ZnO shows also a moment of 0.3 muB/Sc. Magnetization is very anisotropic, with variations of up to a fact

A. E. Allahverdyan, Zh. S. Gevorkian, Chin-Kun Hu, Ming-Chya Wu

We consider force-induced unzipping transition for a heterogeneous DNA model with a correlated base-sequence. Both finite-range and long-range correlated situations are considered. It is shown that finite-range correlations increase stability of DNA with respect to the external unzipping force. Due to long-range correlations the number of unzipped base-pairs

Stellan Ostlund, A. Karlhede, T. H. Hansson

We develop an exact generalized Bogoliubov transformation for the spin 3/2 Hubbard model with large anti-Hunds rule coupling near half filling. Since our transformation is unitary, we can thereafter employ standard approximate mean field theory methods in the full Hilbert space to analyze the doped Mott insulator, in contrast to a conventional approach based

T. H. Hansson, J. Kailasvuori, A. Karlhede, R. von Unge

We show how to incorporate fractionally charged quasielectrons in the finite quantum Hall matrix model.The quasielectrons emerge as combinations of BPS solitons and quasiholes in a finite matrix version of the noncommutative $ϕ^4$ theory coupled to a noncommutative Chern-Simons gauge field. We also discuss how to properly define the charge density in the cla

C. Gabriel, E. Sherman, T. C. Lang, M. Aichhorn

We investigate charge ordering in a quarter-filled ladder at finite temperature by determinantal Quantum Monte Carlo. The sign problem is moderate in a wide range of model parameters relevant for NaV2O5. The charge order parameter exhibits a crossover as a function of inverse temperature on finite systems. Above a critical nearest neighbor Coulomb repulsion,

Luis A. Pugnaloni

A discussion on the viscoelastic properties of weakly attractive colloids and the relation to a newly developed percolation theory is presented. The need for taking into account the particle-particle bond lifetime in order to compare rheological and percolation estimates of the sol-gel transition is stressed. Recent molecular dynamics simulations and general

G. G. Kozlov

It is shown that the light scattered by a finite 2D crystal strip in the region of an exciton resonance should display strong backscattering. This phenomenon is related to the exciton reflection from the edge of the strip.

Y. Koval, M. V. Fistul, A. V. Ustinov

We report an experimental and theoretical study of the phase diffusion in small Josephson junctions under microwave irradiation. A peculiar enhancement of the phase diffusion by microwaves is observed. The enhancement manifests itself by a pronounced current peak in the current-voltage characteristics. The voltage position $V_{\rm top}$ of the peak increases

R. Englman, A. Yahalom

Recent novel mesoscopic two-arm experiments involving quantum dots, electron interferometry and Aharononov-Bohm effects have enabled measuring the electron transmission probabilities and the phases. Unexpected features in the phases as function of the gap voltage U have simulated intensive theoretical works. It is shown in this paper that the phases (f) and

J. Luczka, B. Zaborek

A diffusion process of a Brownian particle in a medium of temperature $T$ is re-considered. We assume that temperature of the medium fluctuates around its mean value. The velocity probability distribution is obtained. It is shown that the stationary state is not a thermodynamic equilibrium state described by the Maxwell distribution. Instead a nonequilibrium

Michael Biehl

A brief introduction is given to Kinetic Monte Carlo (KMC) simulations of epitaxial crystal growth. Molecular Beam Epitaxy (MBE) serves as the prototype example for growth far from equilibrium. However, many of the aspects discussed hear would carry over to other techniques as well. A variety of approaches to the modeling and simulation of epitaxial growth h

Dipta Bhanu Ghosh, Molly De, S. K. De

Full potential spin-polarized self-consistent electronic structure calculation s have been performed on LaB$_{6}$, EuB$_{6}$ and YbB$_{6}$ using Linear Muffin- Tin Orbital Method. The electronic structure of EuB$_{6}$ shows a small overlap near the Fermi level. This is in disagreement with the recent ARPES study. The r eflectivity spectrum shows a plasma res

F. Kadlec, S. Kamba, P. Kuzel, C. Kadlec

Time-domain THz transmission experiment was performed on a $\rm SrBi_2Ta_2O_9$ film deposited on sapphire substrate. Temperatures between 300 and 923 K were investigated and complex permittivity spectra of the film were determined. The lowest frequency optic phonon near 28 cm$^{-1}$ reveals a slow monotonic decrease in frequency on heating with no significan

Bertrand M. Roehner

We describe and document three mechanisms by which corporations can influence or even control stock prices. (i) Parent and holding companies wield control over other publicly traded companies. (ii) Through clever management of treasury stock based on buyback programs and stock issuance, stock price fluctuations can be amplified or curbed. (iii) Finally, hist

Efrat Shimshoni

Experimental studies of the transitions from a primary quantum Hall (QH) liquid at filling factor 1/k (with k an odd integer) to the insulator have indicated a ``quantized Hall insulator&#39;&#39; (QHI) behavior: while the longitudinal resistivity diverges with decreasing temperature and current bias, the Hall resistivity remains quantized at the value $k h/

Robert Englman, Asher Yahalom

We treat a system (a molecule or a solid) in which electrons are coupled linearly to any number and type of harmonic oscillators and which is further subject to external forces of arbitrary symmetry. With the treatment restricted to the lowest pair of electronic states, approximate &#34;vibronic&#34; (vibration-electronic) ground state wave functions are con

M. M. Fogler

We consider a set of electrostatic problems relevant for determining the real-space structure and the ground-state energy of a two-dimensional electron liquid subject to smooth external potentials. Three fundamental geometries are investigated: an elongated metallic island, an antidot, and a constriction. In the first two cases complete closed-form analytica

Ehud Altman, Yariv Kafri, Anatoli Polkovnikov, Gil Refael

We study one dimensional disordered bosons at large commensurate filling. Using a real space renormalization group approach we find a new random fixed point which controls a phase transition from a superfluid to an incompressible Mott-glass. The transition can be tuned by changing the disorder distribution even with vanishing interactions. We derive the prop

E. Cuevas

The nearest level spacing distribution $P_c(s)$ of $d$-dimensional disordered models ($d=1$ and 2) with long-range random hopping amplitudes is investigated numerically at criticality. We focus on both the weak ($b^d \gg 1$) and the strong ($b^d \ll 1$) coupling regime, where the parameter $b^{-d}$ plays the role of the coupling constant of the model. It is

J. Kaupuzs

We have extended our method of grouping of Feynman diagrams (GFD theory) to study the transverse (G_t) and longitudinal (G_l) Greens functions in phi^4 model below the critical point (T<T_c) in presence of an infinitesimal external field. Our method allows a qualitative analysis not cutting the perturbation series. We have shown that the critical behavior of

Kurtis A. Williams, Michael Bolte, James Liebert

We present spectroscopic observations of the remaining four candidate white dwarfs in Praesepe. All four candidates are quasars with redshifts between 0.8 and 2.8. One quasar, LB 6072, is observed to have a strong metal-line absorption system blueward of the quasar redshift. The lack of additional white dwarfs in Praesepe leaves the total known white-dwarf p

William H. Kinney

I examine the status of inflationary cosmology in light of the first-year data from the WMAP satellite, focusing on the simplest models of inflation: those driven by a single scalar field. The WMAP observation of the Cosmic Microwave Background is the first unified, self-consistent data set capable of putting meaningful constraints on the inflationary parame

Gabriela Canalizo, Claire Max, Robert Antonucci, David Whysong

We present preliminary results from high resolution (~ 0.05&#34;) adaptive optics observations of Cygnus A. The images show a bi-conic structure strongly suggestive of an obscuring torus around a quasar nucleus. A bright (K&#39;=18.5) point source is found near the expected position of the nucleus. We interpret this source as the hot inner rim of the torus s

Wil van Breugel, Chris Fragile, Stephen Croft, Wim de Vries

We discuss obbservations and numerical simulations which show that radiative shocks in jet-cloud collisions can trigger the collapse of intergalactic clouds and subsequent star formation in low luminosity, &#39;FR-I&#39; type, radio galaxies.

Paul Martini

The results of bar-driven mass inflow are directly observable in high-resolution HST observations of their circumnuclear regions. These observations reveal a wealth of structures dominated by dust lanes, often with a spiral-like morphology, and recent star formation. Recent work has shown that some of these structures are correlated with the presence or abse

Paul Martini, S. E. Persson, D. C. Murphy, C. Birk

PANIC (Persson&#39;s Auxiliary Nasmyth Infrared Camera) is a near-infrared camera designed to operate at any one of the f/11 folded ports of the 6.5m Magellan telescopes at Las Campanas Observatory, Chile. The instrument is built around a simple, all-refractive design that reimages the Magellan focal plane to a plate scale of 0.125&#39;&#39; pixel^{-1} onto

Brian Fields, Subir Sarkar

A critical review is given of the current status of cosmological nucleosynthesis. In the framework of the standard model with 3 types of relativistic neutrinos, the baryon-to-photon ratio, η, corresponding to the inferred primordial abundances of helium-4 and lithium-7 is presently ~2 σbelow the value implied by the abundance of deuterium. The latter value i

Miguel F. Morales

Recent theoretical developments for observing the Epoch of Reionization (EOR) have concentrated on the power spectrum signature of redshifted 21 cm emission. These studies have demonstrated the great potential of statistical EOR observations, however, the sensitivity calculations for proposed low frequency radio arrays have been highly approximate. The forma

Manuel Guedel

X-ray emission from stars in the cool half of the Hertzsprung-Russell diagram is generally attributed to the presence of a magnetic corona that contains plasma at temperatures exceeding 1 million K. Coronae are ubiquitous among these stars, yet many fundamental mechanisms operating in their magnetic fields still elude an interpretation through a detailed phy

G. C. Jordan, B. S. Meyer

We demonstrate that nucleosynthesis in rapid, high-entropy expansions of proton-rich matter from high temperature and density can result in a wider variety of abundance patterns than heretofore appreciated. In particular, such expansions can produce iron-group nuclides, p-process nuclei, or even heavy, neutron-rich isotopes. Such diversity arises because the

H. E. S. S. Collaboration, :, F. Aharonian

H.E.S.S. - the High Energy Stereoscopic System- is a new system of large atmospheric Cherenkov telescopes for GeV/TeV astronomy. Each of the four telescopes of 107 m^2 mirror area is equipped with a 960-pixel photomulitiplier-tube camera. This paper describes the methods used to convert the photomultiplier signals into the quantities needed for Cherenkov ima

Georges Meylan, Juan P. Madrid, Duccio Macchetto

Since its launch in April 1990, the Hubble Space Telescope (HST) has produced an increasing flow of scientific results. The large number of refereed publications based on HST data allows a detailed evaluation of the effectiveness of this observatory and of its scientific programs. This paper presents the results of selected science metrics related to paper c

D. S. Gorbunov, P. G. Tinyakov, I. I. Tkachev, S. V. Troitsky

Previously suggested correlations of BL Lac type objects with the arrival directions of the ultra-high-energy cosmic ray primaries are tested by making use of the HiRes stereoscopic data. The results of the study support the conclusion that BL Lacs may be the cosmic ray sources and suggest the presence of a small (a few percent) fraction of neutral primaries

M. Almudena Prieto, Klaus Meisenheimer

First results from the AGN-Heidelberg program aimed at spatially resolving the central pc region of the closest Active Galactic Nuclei are presented. The core region of prototype active nuclei are clearly unveiled at IR waves and at distances from the nucleus - few pc- where circumnuclear starforming regions appear not to be present. Within that perspective,

Giancarlo Pace, Luca Pasquini

Measured from high-resolution spectra, we present Ca II K line chromospheric fluxes in 35 G dwarf stars of 5 open clusters to determine the age-activity-rotation relationship from the young Hyades and Praesepe (0.6 Gyr) to the old M 67 (~ 4.5 Gyr) through the two intermediate age clusters IC 4651 and NGC 3680 (~ 1.7 Gyr). Our data show that a dramatic decrea

R. Parra, J. E. Conway, M. Elitzur

We present a model for the OH megamaser emission in the starburst galaxy IIIZw35. The observed diffuse and compact OH maser components in this source are explained by a single phase of unsaturated clumpy gas distributed in a thin ring structure and amplifying background continuum. We emphasize the importance of clumpiness in the OH masing medium, an effect t

J. H. He, P. S. Chen

This paper analyzes the 53.3um line in the ISO LWS spectra towards a similar sample of OH/IR sources. We find 137 LWS spectra covering 53.3um and associated with 47 galactic OH/IR sources. Ten of these galactic OH/IR sources are found to show and another 5 ones tentatively show the 53.3um absorption while another 7 sources highly probably do not show this li

A. Rodriguez-Ardila, A. Prieto, S. M. Viegas

VLT and NTT spectra are used to examine the nuclear and extended coronal line emission in a sample of well-known Seyfert 1 and 2 galaxies. The excellent spatial resolution obtained with VLT allowed us to map [SiVI] 1.963 $μ$m and [SiVII] 2.48 $μ$m on scales of up to 20 pc. Coronal line emission, extended to distances of $\sim$100 pc, is detected in some of t

Sachiko Onodera, Jin Koda, Yoshiaki Sofue, Kotaro Kohno

We report on high-resolution interferometer observations of the 12CO(J=1-0) emission in the central 5 kpc region of the Seyfert 2 galaxy NGC 4501. The observations were made using the Nobeyama Millimeter Array during a long-term CO line survey of Virgo spirals. The major features are: (1) a nuclear concentration with a radius of r~5&#39;&#39; (390 pc), which

M. S. N. Kumar, M. Tafalla, R. Bachiller

We present new high-sensitivity high-resolution mm-wave observations of the Onsala 1 ultra-compact HII region that bring to light the internal structure of this massive star forming cloud. The 1.2 mm continuum map obtained with the IRAM 30-m radiotelescope (~11&#34; resolution) shows a centrally peaked condensation of 1&#39; size (~0.5 pc at the assumed dist

D. Baba, T. Nagata, T. Nagayama, C. Nagashima

We present deep near-infrared (J, H, Ks) images toward an embedded cluster which lies in a C18O clump in the cloud C of the Vela Molecular Ridge. This cluster has at least ~ 350 members and a radius of ~ 0.5 pc. The stellar surface number density is approximately 3000 stars pc^-2 in the central 0.1 pc x 0.1 pc region of the cluster. This is much higher than

R. D. Alexander, C. J. Clarke, J. E. Pringle

We present the results of a theoretical study investigating the effects of photoionization and heating by X-rays on discs around low-mass stars. In particular we address the question of whether or not X-rays can drive a disc wind. First, we construct a 1-dimensional ``quasi-hydrostatic&#39;&#39; model, which solves for the vertical structure introduced by X-

L. Magrini, M. Perinotto, A. Mampaso, R. L. M . Corradi

Using spectroscopic data presented in Magrini et al. (2003), we have analyzed with the photoionization code CLOUDY 94.00 (Ferland et al. 1998) 11 Planetary Nebulae belonging to the spiral galaxy M 33. Central star temperatures and nebular parameters have been determined. In particular the chemical abundances of He/H, O/H, N/H, Ar/H, and S/H have been measure

Tadeusz Wibig

In this paper we will discuss the problem of Ultra High Energy Cosmic Rays (UHECR) and show that the idea of a Single Source Model established by Erlykin and Wolfendale (1997) to explain the features seen in cosmic ray energy spectra around the 10**15 eV region can be successfully applied also for the much higher energies. The propagation of UHECR (of energi

Doug Johnstone, James Di Francesco, Helen Kirk

We have observed continuum emission at lambda = 850 microns over ~4 square degrees of the Ophiuchus star-forming cloud using SCUBA on the JCMT, producing a submillimetre continuum map twenty times larger than previous Ophiuchus surveys. Our sensitivity is 40 mJ/beam, a factor of ~2 less sensitive than earlier maps. Using an automated identification algorithm

M. S. N. Kumar, U. S. Kamath, C. J. Davis

We present sub-arcsecond (0.35&#34;-0.9&#34;), near-infrared J,H,K band photometric observations of six fields along the W51 Giant Molecular Cloud (W51 GMC). Our observations reveal four new, embedded clusters and provide a new high-resolution (0.35&#34;) view of the W51IRS2 (G49.5-0.4) region. The cluster associated with G48.9-0.3 is found to be a double cl

Yanbin Yang, Zhiying Huo, Xu Zhou, Suijian Xue

We present Chandra X-ray observations of galaxy cluster A168 (z=0.045). Two X-ray peaks with a projected distance of 676 kpc are found to be located close to two dominant galaxies, respectively. Both peaks are significantly offset from the peak of the number density distribution of galaxies. This suggests that A168 consists of two subclusters, a northern sub

Takuji Tsujimoto

The recent discovery of a new population of stars exhibiting unusual elemental abundance patterns characterized by enhanced Ti to Ga elements and low alpha and n-capture elements suggests the contribution of a new class of supernovae, probably a kind of Type Ia supernovae associated with close binary evolution. The role of these supernovae in chemical evolut

Mariano Anabitarte, Mauricio Bellini

The evolution of the inflaton field fluctuations from gauge-invariant metric fluctuations is discused. In particular, the case of a symmetric $ϕ_c$-exponential potential is analyzed.

Debashis Ghoshal

The tachyon field of p-adic string theory is made noncommutative by replacing ordinary products with noncommutative products in its exact effective action. The same is done for the boundary string field theory, treated as the p -> 1 limit of the p-adic string. Solitonic lumps corresponding to D-branes are obtained for all values of the noncommutative paramet

S. L. A. de Queiroz

We study the probability distributions of interface roughness, sampled among successive equilibrium configurations of a single-interface model used for the description of Barkhausen noise in disordered magnets, in space dimensionalities $d=2$ and 3. The influence of a self-regulating (demagnetization) mechanism is investigated, and evidence is given to show

Ariyeh H. Maller, James S. Bullock

The standard treatment of cooling in Cold Dark Matter halos assumes that all of the gas within a ``cooling radius&#39;&#39; cools and contracts monolithically to fuel galaxy formation. Here we take into account the expectation that the hot gas in galactic halos is thermally unstable and prone to fragmentation during cooling and show that the implications are

Roberto Contino, Alex Pomarol

The holographic interpretation is a useful tool to describe 5D field theories in a 4D language. In particular it allows one to relate 5D AdS theories with 4D CFTs. We elaborate on the 5D/4D dictionary for the case of fermions in AdS$_5$ with boundaries. This dictionary is quite useful to address phenomenological issues in a very simple manner, as we show by

Eduardo del Pozo Garcia

A numerical coincidence Dp of -0.000489 was found between the ratios of proton emission at 459-keV and cosmic background at 0.25-keV respect to proton and to electron proper energy respectively. Multiplying 459-keV and 0.25-keV by Dp, two more numerical coincidences were found with 0.1-keV background and 0.06-eV of neutrino energy, respectively. Global criti

CDF Collaboration

We report the first measurements of inclusive W and Z cross sections times leptonic branching ratios for p-pbar collisions at $\sqrt{s} = 1.96$ TeV, based on their decays to electrons and muons. The data correspond to an integrated luminosity of 72 pb-1 recorded with the CDF detector at the Fermilab Tevatron. We test e-mu universality in W decays, and we mea

Emina Alibegovic

We give a description of $Hom(G,L)$, where $L$ is a limit group (fully residually free group). We construct a finite diagram of groups, Makanin-Razborov diagram, that gives a convinient representation of all such homomorphisms.

J. Menezes, P. P. Avelino, C. Santos

We study static cosmic string solutions in the context of Bekenstein-type models. We show that there is a class of models of this type for which the classical Nielsen-Olesen vortex is still a valid solution. However, in general static string solutions in Bekenstein-type models strongly depart from the standard Nielsen-Olesen solution with the electromagnetic

J. Aaronson, H. Nakada, O. Sarig

Let $\Om$ be a Borel subset of $S^\Bbb N$ where $S$ is countable. A measure is called exchangeable on $\Om$, if it is supported on $\Om$ and is invariant under every Borel automorphism of $\Om$ which permutes at most finitely many coordinates. De-Finetti&#39;s theorem characterizes these measures when $\Om=S^\Bbb N$. We apply the ergodic theory of equivalenc