June 2001 arXiv papers — page 10

P. Bouwknegt, A. L. Carey, V. Mathai, M. K. Murray

In this note we introduce the notion of bundle gerbe K-theory and investigate the relation to twisted K-theory. We provide some examples. Possible applications of bundle gerbe K-theory to the classification of D-brane charges in non-trivial backgrounds are discussed.

M. Hanawa, Y. Muraoka, T. Tayama, T. Sakakibara

We report the first pyrochlore oxide superconductor Cd2Re2O7. Resistivity,magnetic susceptibility,and specific heat measurements on single crystals evidence a bulk superconductivity at 1 K. Another phase transition found at 200 K suggests that a peculiar electronic structure lies behind the superconductivity.

Y. Otsuka, Y. Morita, Y. Hatsugai

We investigate anisotropic charge fluctuations in the two-dimensional Hubbard model at half filling. By the quantum Monte Carlo method, we calculate a momentum-resolved charge compressibility $κ(\bm{k}) = {d < n(\bm{k}) >}/{d μ}$, which shows effects of an infinitesimal doping. At the temperature $T \sim {t^2}/{U}$, $κ(\bm{k})$ shows peak structure at the $(

Sergei M. Kopeikin, Juan Ramirez, Bahram Mashhoon, Mikhail V. Sazhin

A new gauge-invariant approach for describing cosmological perturbations is developed. It is based on a physically motivated splitting of the stress-energy tensor of the perturbation into two parts - the bare perturbation and the complementary perturbation associated with stresses in the background gravitational field induced by the introduction of the bare

G. Bitton, W. P. Grice, J. Moreau, L. Zhang

A new ultra bright pulsed source of polarization entangled photons has been realized using type-II phase matching in spontaneous parametric down conversion process in two cascaded crystals. The optical axes of the crystals are aligned in such a way that the extraordinarily (ordinarily) polarized cone from one crystal overlaps with the ordinarily (extraordina

W. A. Hofer

The violation of Bell&#39;s inequalities in Einstein-Podolsky-Rosen experiments has been demonstrated for photons and ions. In all experiments of this kind the relation between visibility, efficiency, and Bell violation is generally unknown. In this paper we show that simulations based on a local hidden variables models for entangled photons provide this inf

Frank Julicher

Active phenomena which involve force generation and motion play a key role in a number of phenomena in living cells such as cell motility, muscle contraction and the active transport of material and organelles. Here we discuss mechanical oscillations generated by active systems in cells. Examples are oscillatory regimes in muscles, the periodic beating of ax

L. Periale, V. Peskov, P. Carlson, T. Francke

Noble gases and liquids are excellent scintillators and this opens a unique opportunity to directly detect the primary scintillation light produced in these media by photons or particles. This signal can be used for several purposes, for example as a start signal for TPCs or for particles identification. Usually photomultipliers (PMs) are used for the detect

A. Ozerov, I. Ispolatov, J. Lees

A model is proposed to explain temporal patterns of activity in a class of periodically exploding Strombolian-type volcanos. These patterns include major events (explosions) which follow each other every 10-30 minutes and subsequent tremor with a typical period of 1 second. This two-periodic activity is thought to be caused by two distinct mechanisms of accu

E. G. Drukarev, M. G. Ryskin, V. A. Sadovnikova

We review various approaches to the calculation of QCD condensates and of the nucleon characteristics in nuclear matter. We show the importance of their self-consistent treatment. The first steps in such treatment appeared to be very instructive. It is shown that the alleged pion condensation anyway can not take place earlier than the restoration of the chir

J. F. Liang, J. R. Beene, H. Esbensen, A. Galindo-Uribarri

Angular distributions of fluorine and oxygen produced from 170 MeV 17^F incident on 208^Pb were measured. The elastic scattering data are in good agreement with optical model calculations using a double-folding potential and parameters similar to those obtained from 16^O+208^Pb. A large yield of oxygen was observed near θ_lab=36 deg. It is reproduced fairly

M. Or-Guil, J. Krishnan, I. G. Kevrekidis, M. Bar

We investigate the instabilities and bifurcations of traveling pulses in a model excitable medium; in particular we discuss three different scenarios for the loss of stability resp. the disappearance of stable pulses. In numerical simulations beyond the instabilities we observe replication of pulses (backfiring) resulting in complex periodic or spatiotempora

Govindan Rangarajan

In order to perform numerical studies of long-term stability in nonlinear Hamiltonian systems, one needs a numerical integration algorithm which is symplectic. Further, this algorithm should be fast and accurate. In this paper, we propose such a symplectic integration algorithm using polynomial map refactorization of the symplectic map representing the Hamil

Yurii V. Brezhnev

The general technique of derivation of Dubrovin&#39;s equation for the arbitrary operator pencils is suggested. The question of unique recovering of the finite-gap potential by coordinates of zeroes of the Psi-function is discussed. The crucial result of the paper is an autonomous form of Dubrovin&#39;s equations and new trace-formulas for nontrivial spectra

W. Kirsch, B. Simon

We show that approach to equilibrium in certain forced Burgers equations is implied by a decay estimate on a suitable intrinsic semigroup estimate, and we verify this estimate in a variety of cases including a periodic force.

Miloslav Znojil

We show that the PT symmetric Hamiltonians (and their generalizations defined in the text) may be all assigned the projected (so called Feshbach or effective) nonlinear Hamiltonians which are &#34;locally&#34; Hermitian. This implies that many (if not all) of the bound-state energies may be real in a broad domain of Hermiticity-violating interactions. A comp

Paul D. Mitchener

In this paper we develop an axiomatic approach to coarse homology theories. We prove a uniqueness result concerning coarse homology theories on the category of `coarse CW-complexes&#39;. This uniqueness result is used to prove a version of the coarse Baum-Connes conjecture for such spaces.

Bodo Lass

Salikhov has proved a conjecture of Kontsevich and Shoikhet by reducing it to the consideration of three families of graphs, a consideration which was left to the reader for two of those families. We show, that the conjecture is just a very particular case of the classical theorem on the Euler characteristic, well explicated by Teleman.

Boris A. Zalesky

The network flow optimization approach is offered for restoration of grayscale and color images corrupted by noise. The Ising models are used as a statistical background of the proposed method. The new multiresolution network flow minimum cut algorithm, which is especially efficient in identification of the maximum a posteriori estimates of corrupted images,

M. K. Murray, D. Stevenson

We use bundle gerbes and their connections and curvings to obtain an explicit formula for a de Rham representative of the string class of a loop group bundle. This is related to earlier work on calorons.

Xianzhe Dai

In this note we study the problem of conformally flat structures bounding conformally flat structures and show that the eta invariants give obstructions. These lead us to the definition of an abelian group, the conformal cobordism group, which classifies the conformally flat structures according to whether they bound (higher dimensional) conformally flat str

Jason Fulman

We give generating functions for Gauss sums for finite general linear and unitary groups. For the general linear case only our method of proof is new, but we deduce a bound on Kloosterman sums which is sometimes sharper than Deligne&#39;s bound from algebraic geometry.

Iosif Polterovich

We present a concise explicit expression for the heat trace coefficients of spheres. Our formulas yield certain combinatorial identities which are proved following ideas of D. Zeilberger. In particular, these identities allow to recover in a surprising way some known formulas for the heat trace asymptotics. Our approach is based on a method for computation o

Alexander V. Karabegov, Martin Schlichenmaier

We use a natural affine connection with nontrivial torsion on an arbitrary almost-Kaehler manifold which respects the almost-Kaehler structure to construct a Fedosov-type deformation quantization on this manifold.

Karmadeva Maharana

We perform the group analysis of Witten&#39;s equations of motion for a particle moving in the presence of a magnetic monopole, and also when constrained to move on the surface of a sphere, which is the classical Wess-Zumino-Witten model. We also consider variations of this model. Our analysis gives the generators of the corresponding Lie point symmetries. T

Yan-Gang Miao, Harald J. W. Mueller-Kirsten, Dae Kil Park

A Siegel-type chiral p-form action is proposed in D=2(p+1) spacetime dimensions. The approach we adopt is to realize the symmetric second-rank Lagrange-multiplier field, introduced in Siegel&#39;s action, in terms of a normalized multiplication of two (q+1)-form fields with q indices of each field contracted in the even p case, or of two pairs of (q+1)-form

G. L. Fogli, E. Lisi, D. Montanino, A. Palazzo

We briefly discuss some implications of the first solar νresults from the Sudbury Neutrino Observatory (SNO) experiment in the charged-current channel. We first show that the present SNO response function is very similar to the Super-Kamiokande (SK) one above 8.6 MeV in kinetic electron energy. On the basis of such equivalence we confirm, in a completely mod

Victor Goncalves

A dense parton system is expected to be formed in the early stage of relativistic heavy-ion collisions at RHIC energies and above. The probability of a quark gluon plasma production and the resulting strength of its signatures depends strongly on the initial conditions associated to the distributions of partons in the nuclear wave functions. At very high ene

T. Binoth, J. P. Guillet, G. Heinrich, C. Schubert

We calculate a class of one-loop six-point amplitudes in the Yukawa model. The construction of multi-particle amplitudes is done in the string inspired formalism and compared to the Feynman diagrammatic approach. We show that there exists a surprisingly efficient way of calculating such amplitudes by using cyclic identities of kinematic coefficients and disc

S. M. Barr

Non-trivial patterns of quark and lepton masses and mixings can arise without there being any underlying flavor symmetry that distinguishes among the three families. Two realistic examples are given.

S. M. Barr, D. Seckel

It is suggested that the true ground state of the world has exactly vanishing vacuum energy and that the cosmological constant that seems to have been observed is due to our region of the universe being stuck in a false vacuum, whose energy is split from the true vacuum by non-renormalizable operators that are suppressed by powers of the Planck scale. It is

Krishnendu Mukherjee

We compute the free energy density of QCD to order $α_s$ at very high density and non-zero quark masses. The counterterms needed to renormalise the theory to order $α_s$ is same as the vacuum (non-zero density) theory. We investigate the response of the theory to non-zero quark masses and chemical potentials. We study quark number density and quark number su

V. Bozza, S. Capozziello, G. Lambiase, G. Scarpetta

Neutrino flavor oscillations are analyzed in the framework of Quantum Geometry model proposed by Caianiello. In particular, we analyze the consequences of the model for accelerated neutrino particles which experience an effective Schwarzschild geometry modified by the existence of an upper limit on the acceleration, which implies a violation of the equivalen

Bohdan Grzadkowski, Jose Wudka

The triviality and vacuum stability bounds on the Higgs-boson mass are revisited in the presence of new interactions parameterized in a model-independent way by an effective lagrangian. When the scale of new physics is below 50 TeV the triviality bound is unchanged but the stability lower bound is increased by 40-60 GeV. Should the Higgs-boson mass be close

Andrea Banfi, Giulia Zanderighi

We review theoretical methods employed to study non-perturbative contributions to e^+e^- event-shapes and discuss their phenomenological relevance.

S. P. Baranov, A. V. Lipatov, N. P. Zotov

Processes of heavy quark production at HERA, TEVATRON and THERA energies are considered using the semihard ($k_T$ factorization) QCD approach with emphasis on the BFKL dynamics of gluon distributions.

A. V. Belitsky, A. Kirchner, D. Müller

We consider the azimuthal angle dependence in the cross section of the hard leptoproduction of a photon on a nucleon target. We show that this dependence allows to define observables that isolate the twist-two and twist-three sectors in the deeply virtual Compton scattering amplitude. All twist-two and twist-three Compton form factors can be extracted from m

V. Yu. Lazur, V. M. Dobosh, V. V. Rubish, M. D. Melika

An additional spheroidal integral of motion and a group of dynamic symmetry in a model quantum-mechanical problem of two centres eZ_{1}Z_{2}omega with Coulomb and oscillator interactions is obtained, the group properties of its solutions being studied. P(3) \otimes P(2,1), P(5,1) and P(4,2) groups are considered as the dynamic symmetry groups of the problem,

Yin Xi, Ma Wen-Gan, Wan Lang-Hui, Jiang Yi

We examine the process $γγ\to \tildeχ^{+} τ^{-}$ at photon-photon collider in the minimal supersymmetric standard model(MSSM) with R-parity violation, where all the one-loop diagrams are considered. We mainly discuss the effects of bilinear breaking terms, and conclude that their contributions may be important compared with trilinear terms. Our results show

L. Zawiejski

The charged multiplicity fluctuations in deep-inelastic scattering (DIS) are investigated to test perturbative QCD and local parton hadron duality (LPHD). The fluctuations were measured with the ZEUS detector at HERA in restricted phase space domains in the current Breit frame region. The measurements are compared to analytic pQCD + LPHD predictions and QCD-

Sijie Gao, Robert M. Wald

We investigate both the ``physical process&#39;&#39; version of the first law and the second law of black hole thermodynamics for charged and rotating black holes. We begin by deriving general formulas for the first order variation in ADM mass and angular momentum for linear perturbations off a stationary, electrovac background in terms of the perturbed non-

G. Papini, G. Lambiase

Spin-rotation coupling, or Mashhoon effect, is a phenomenon associated with rotating observers. We show that the effect exists and plays a fundamental role in the determination of the anomalous magnetic moment of the muon.

Adwait Ratnaparkhi

We present a hybrid statistical and grammar-based system for surface natural language generation (NLG) that uses grammar rules, conditions on using those grammar rules, and corpus statistics to determine the word order. We also describe how this surface NLG module is implemented in a prototype conversational system, and how it attempts to model informational

Floris Geerts

We show that there is a query expressible in first-order logic over the reals that returns, on any given semi-algebraic set A, for every point a radius around which A is conical. We obtain this result by combining famous results from calculus and real algebraic geometry, notably Sard&#39;s theorem and Thom&#39;s first isotopy lemma, with recent algorithmic r

J. R. Petta, D. C. Ralph

The effects of spin-orbit scattering on discrete electronic energy levels are studied in copper, silver, and gold nanoparticles. Level-to-level fluctuations of the effective $g$-factor for Zeeman splitting are characterized, and the statistics are found to be well-described by random matrix theory predictions. The strength of spin-orbit scattering increases

J. Kainz, S. A. Mikhailov, A. Wensauer, U. Roessler

We present a new method for calculating ground state properties of quantum dots in high magnetic fields. It takes into account the equilibrium positions of electrons in a Wigner cluster to minimize the interaction energy in the high field limit. Assuming perfect spin alignment the many-body trial function is a single Slater determinant of overlapping oscilla

C. P. Warren, L. M. Sander, I. M. Sokolov

We consider a spatial model related to bond percolation for the spread of a disease that includes variation in the susceptibility to infection. We work on a lattice with random bond strengths and show that with strong disorder, i.e. a wide range of variation of susceptibility, patchiness in the spread of the epidemic is very likely, and the criterion for epi

Alexei V. Tkachenko

We study theoretically a binary system in which an attraction of unlike particles is combined with a type-independent soft core repulsion. The possible experimental implementation of the system is a mixture of DNA-covered colloids, in which both the repulsion and the attraction may be induced by DNA solution. The system is shown to exhibit surprisingly diver

J. L. Gavilano, D. Rau, Sh. Mushkolaj, H. R. Ott

We report the observation of an anomalous {27}Al-NMR response of a single grain Al_{72.4}Pd_{20.5}Mn_{7.1} icosahedral quasicrystal at low temperatures. In an external magnetic field of 6 T and upon decreasing temperature, we observe a sharp 100 % increase of the resonance linewidth at 2.5 K. No further changes of the linewidth are observed down to 0.05 K. T

M. A. Baranov, I. S. Burmistrov, A. M. M. Pruisken

We consider the finkelstein action describing a system of spin polarized or spinless electrons near two dimensions, in the presence of disorder as well as the Coulomb interactions.We extend the renormalization group analysis of our previous work and evaluate the metal-insulator transition of the electron gas to second order in an (d-2) expansion. We obtain t

Keshav N. Shrivastava

We find that a bilayer of semiconductors emits a new Goldstone quasiparticle when Landau levels in the layers are half filled. The emission of the new quasiparticle is associated with the divergence in the energy of the system characteristic of a phase transition. There is a Bose condensation of the pairs of quasiparticles in which one electron has spin up a

M. K. Hassan, J. Kurths

We consider the fragmentation process with mass loss and discuss self-similar properties of the arising structure both in time and space, focusing on dimensional analysis. This exhibits a spectrum of mass exponents $θ$, whose exact numerical values are given for which $x^{-θ}$ or $t^{θz}$ has the dimension of particle size distribution function $ψ(x,t)$, whe

Adriaan M. J. Schakel

It is argued that the presence of a nonanalytic term in the effective potential of the Ginzburg-Landau model is immaterial as far as the order of the superconductor-normal phase transition is concerned. To achieve agreement with the renormalization group, the effective potential has to be extended to include derivative terms, which provide the theory with a

Mark I. Shliomis

Comment on the paper &#34;Novel Convective Instabilities in a Magnetic Fluid&#34; by W. Luo, T. Du, and J. Huang, Phys. Rev. Lett., v.82, p.4134 (1999).

Xin-Qi Li, YiJing Yan

Within the Büttiker dephasing model, the backscattering in the dephasing process is eliminated by setting a proper boundary condition. Explicit expression is carried out for the effective total tunneling probability in the presence of multiple pure dephasing scatterers with partial coherence. The derived formula is illustrated analytically by various limitin

J. Heinrichs

We present an analytical study of the Lyapunov exponent for electronic states in a disordered tight-binding ring, with N sites of spacing c, in the presence of a non-hermitian field component h, for weak disorder. This system has been proposed by Hatano and Nelson (HN) as a model for the depinning of flux lines bound to columnar defects in a superconducting

J. Heinrichs

We reconsider the study of persistent currents in a disordered one-dimensional ring threaded by a magnetic flux, using he one-band tight-binding model for a ring of N-sites with random site energies. The secular equation for the eigenenergies expressed in terms of transfer matrices in the site representation is solved exactly to second order in a perturbatio

Shang-Fen Ren, G. Qin

By means of a microscopic valence force field model, a series of novel microscopic interface phonon modes are identified in shell quantum dots(SQDs) composed of a GaAs quantum dot of nanoscale embedded in an AlAs shell of a few atomic layers in thickness. In SQDs with such thin shells, the basic principle of the continuum dielectric model and the macroscopic

F. Much, M. Ahr, M. Biehl, W. Kinzel

We determine the critical layer thickness for the appearance of misfit dislocations as a function of the misfit between the lattice constants of the substrate and the adsorbate from Kinetic Monte Carlo (KMC) simulations of heteroepitaxial growth. To this end, an algorithm is introduced which allows the off-lattice simulation of various phenomena observed in

P. Svoboda, Y. Krupko, L. Smrcka, M. Cukr

We have investigated the magnetoresistance of strongly asymmetric double-well structures formed by a thin AlGaAs barrier grown far from the interface in the GaAs buffer of standard heterostructures. In magnetic fields oriented parallel to the electron layers, the magnetoresistance exhibits an oscillation associated with the depopulation of the higher occupie

J. Heinrichs

The invariant imbedding evolution equations for the amplitude reflection and transmission coefficients of a disordered 1D chain are shown to follow from the continuum limit, for weak disorder, of recursion relations between reflection (transmission) coefficients of Anderson chains of N and N-1 atoms embedded in infinite non-disordered chains. We show that va

Yu. Piskunov, A. Gerashenko, A. Pogudin, A. Ananyev

The 17O and 207Pb NMR spectra were measured in ceramic samples in the metallic phase of BaPb_{1-x}Bi_{x}O_3 oxides (0<x< 0.33). The inhomogeneous magnetic broadening which appears due to a distribution of the Knight shifts was analyzed in detail. It is shown that Bi atoms, which are randomly incorporated in BaPbO_3 parent compound give rise to an increased c

J. Kolorenc, L. Smrcka, P. Streda

In double quantum wells electrons experience a Lorentz force oriented perpendicular to the structure plane when an electric current is driven perpendicular to the direction of an in-plane magnetic field. Consequently, the excess charge is accumulated in one of the wells. The polarization of a bilayer electron system and the corresponding Hall voltage are sho

Anirban Chakraborti

We have studied numerically the frequency distribution $ρ(n)$ of the n-th neighbour along the optimal tour in the Euclidean travelling salesman problem for N cities, in dimensions d=2 and d=3. We find there is no significant dependence of $ρ(n)$ on either the number of cities N or the dimension d.

J. J. Hope

This paper examines the parameter regimes in which coupled atomic and molecular Bose-Einstein condensates do not obey the Gross-Pitaevskii equation. Stochastic field equations for coupled atomic and molecular condensates are derived using the functional positive-P representation. These equations describe the full quantum state of the coupled condensates and

Yasushi Honda, Tsuyoshi Horiguchi

We investigate an $S=1/2$ two-leg spin ladder with a cyclic four-spin exchange interaction whose interaction constant is denoted by $J_4$, by using the density matrix renormalization group method. The interchain and the intrachain interaction constant are denoted by $J_{rung}$ and $J_{\rm leg}$, respectively and assumed to be antiferromagnetic. It turns out

Bambi Hu, Baowen Li

This paper gives a review of our recent work on the quantum Frenkel-Kontorova model. Using the squeezed state theory and the quantum Monte Carlo method, we have studied the effects of quantum fluctuations on the Aubry transition and the behavior of the ground state wave function. We found that quantum fluctuations renormalize the sinusoidal standard map to a

Bambi Hu, Baowen Li, Hong Zhao

In this paper, it is shown that a configuration modulated system described by the Frenkel-Kontorova model can be locked at an incommensurate phase when the quantum zero point energy is taken into account. It is also found that the specific heat for an incommensurate phase shows different parameter-dependence in sliding phase and pinning phase. These findings

Baowen Li, Hong Zhao, Bambi Hu

We study heat conduction in one dimensional mass disordered harmonic and anharmonic lattices. It is found that the thermal conductivity $κ$ of the disordered anharmonic lattice is finite at low temperature, whereas it diverges as $κ\sim N^{0.43}$ at high temperature. Moreover, we demonstrate that a unique nonequilibrium stationary state in the disordered har

Tatiana G. Rappoport, M. A. Continentino

In this paper we investigate the magnetic properties of heavy fermions in the antiferromagnetic and dense Kondo phases in the framework of the Kondo necklace model. We use a mean field renormalization group approach to obtain a temperature versus Kondo coupling $(T-J)$ phase diagram for this model in qualitative agreement with Doniach&#39;s diagram, proposed

Shigeru Koikegami, Synge Todo, Hajime Takayama

We investigate S=1 antiferromagnetic quantum spin chain, whose exchange couplings are strongly disordered. By the real-space renomalization group method, introduced by Ma, Dasgupta, and Hu, the renormalization group flows are analyzed numerically in a plain of the anisotoropy of the exchange coupling vs. the staggered magnetic field. As the result, the Heise

Pratip Bhattacharyya, Bikas K. Chakrabarti, Anirban Chakraborti

We first review the derivation of the exact expression for the average distance $<r_n>$ of the n-th neighbour of a reference point among a set of N random points distributed uniformly in a unit volume of a D-dimensional geometric space. Next we propose a `mean-field\rq theory of $<r_n>$ and compare it with the exact result. The result of the `mean-field\rq t

E. Behar, A. Kinkhabwala, M. Sako, F. Paerels

Preliminary analysis of the X-ray spectrum of NGC 1068 obtained by the RGS spectrometer on board XMM-Newton is presented. A physically consistent model is developed in order to quantitatively describe the reprocessing of the central AGN continuum source into the discrete X-ray emission observed in Seyfert 2 galaxies. All the important atomic processes are ta

J. Noel-Storr, C. M. Carollo, S. A. Baum, R. P. van der Marel

We present initial results of our analysis of line emission produced in gas disks found at the centers of a sample of nearby, radio galaxies with radio jets. We obtained data using STIS (The Space Telescope Imaging Spectrograph) at three parallel slit positions on the nucleus of each galaxy. This allows us to map the H$α$ + [NII] flux, the gas radial velocit

S. Laine, R. P. van der Marel, T. Boeker, J. C. Mihos

We present first results from an HST WFPC2 imaging and STIS spectroscopy program to investigate the structural and star forming properties in the nuclear regions of the Toomre Sequence of merging galaxies. Here we discuss V-band, I-band and H-alpha images of the nuclei. We comment briefly on the connection between the nuclear morphology of the ionized gas an

B. C. Matthews, C. D. Wilson, J. D. Fiege

Polarized 850 micron thermal emission data of the region OMC-3 in the Orion A molecular cloud are presented. These data, taken in 1998 with the SCUBA polarimeter mounted on the James Clerk Maxwell Telescope, have been re-reduced using improved software. The polarization pattern is not suggestive of a uniform field structure local to OMC-3, nor does the orien

D. J. Pisano, Henry A. Kobulnicky, Rafael Guzman, Jesus Gallego

We present Arecibo 21 cm spectroscopy, Keck HIRES Hb spectroscopy, and WIYN R-band images of 11 nearby blue compact galaxies selected to be similar to blue compact star-forming galaxies at intermediate redshifts (0.1<z<1). We detect HI in 10 of 11 sample galaxies, yielding HI masses of 0.3-4x10^9 M_odot, HI linewidths, W_20, of 133-249 km/s, dynamical masses

The NINA Collaboration, A. Bakaldin, A. Galper, S. Koldashov

This article reports nine Solar Energetic Particle events detected by the instrument NINA between October 1998 and April 1999. NINA is a silicon-based particle detector mounted on-board the Russian satellite Resurs-01-N4, which has flown at an altitude of about 800 km in polar inclination since July 1998. For every solar event the power-law He4 spectrum acro

Pauline Barmby

Globular cluster ages are more than just lower limits to the age of the universe; the distribution of ages constraints the timescales for galaxy formation and chemical evolution. Globular cluster populations with different metallicities have now been detected in many galaxies, and understanding how these populations formed requires knowing their relative age

Henk Hoekstra, Howard Yee, Mike Gladders

The Red-Sequence Cluster Survey (RCS) is a 100 square degree galaxy cluster survey designed to provide a large sample of optically selected clusters of galaxies with redshifts 0.1<z<1.4. The survey data are also useful for a variety of lensing studies. Several strong lensing clusters have been discovered so far, and follow up observations are underway. In th

Yu. P. Pskovskii, O. F. Dorofeyev

For two nearby pulsars, formed close to the galactic plane, their host open stellar clusters have been found.

Almudena Alonso-Herrero, Johan H. Knapen

We analyze the statistical properties of the circumnuclear HII regions of a sample of 52 nearby galaxies ($v < 1000km/s) from archival HST/NICMOS H-band and Pa alpha (1.87micron) observations at unprecedented spatial resolutions of between 1 and 30pc. We find HII regions in the central regions of most galaxies, and more than a hundred in 8 galaxies. In contr

M. Contini, L. Formiggini

The spectra of both the inner and outer nebulae in He2-104 are modelled by composite models which accounts consistently for photoionisation and shocks. The temperature of the hot star results Ts = 130 000 K. We suggest that the characteristic &#34;crab legs&#34; in He2-104 are produced by R-T instability at the shock front. The calculated X-ray flux is below

J. A. Eisner, S. R. Kulkarni

With the advent of optical interferometers that will be coming online in the next decade, radial velocity searches for extra-solar planets will be complemented by high angular resolution astrometric measurements. In this paper, we explore the sensitivity of the astrometric technique, and develop an analytical understanding of the sensitivity in the regime wh

D. Whysong, R. Antonucci

Historically the narrow line radio galaxies were thought to be intrinsically nonthermal, and without significant accretion. When the Unified Model came along the compelling observational motivation for this lost some force: some are found to be hidden broad line objects, and in principle that could be the case with all of them. The clear sign of a hidden qua

James S. Bullock

I present an analysis of the density shapes of dark matter halos in LCDM and LWDM cosmologies. The main results are derived from a statistical sample of galaxy-mass halos drawn from a high resolution LCDM N-body simulation. Halo shapes show significant trends with mass and redshift: low-mass halos are rounder than high mass halos, and, for a fixed mass, halo

N. A. Levenson, James R. Graham

With Hubble Space Telescope Wide-Field Planetary Camera 2 observations of the Cygnus Loop supernova remnant, we examine the interaction of an interstellar cloud with the blast wave on physical scales of 10^15 cm. The shock front is distorted, revealing both edge-on and face-on views of filaments and diffuse emission, similar to those observed on larger scale

S. Phillipps, M. J. Drinkwater, M. D. Gregg, J. B. Jones

By utilising the large multi-plexing advantage of the 2dF spectrograph on the Anglo-Australian Telescope, we have been able to obtain a complete spectroscopic sample of all objects in a predefined magnitude range, 16.5<Bj<19.7, regardless of morphology, in an area towards the centre of the Fornax Cluster of galaxies. Among the unresolved or marginally resolv

M. J. Drinkwater, M. D. Gregg, B. A. Holman, M. J. I. Brown

We present the results of a spectroscopic survey of 675 bright (16.5<Bj<18) galaxies in a 6 degree field centred on the Fornax cluster with the FLAIR-II spectrograph on the UK Schmidt Telescope. We measured redshifts for 516 galaxies of which 108 were members of the Fornax Cluster. Nine of these are new cluster members previously misidentified as background

Jozef Klacka

Relativistically covariant equation of motion for real dust particle under the action of electromagnetic radiation is derived. The particle is neutral in charge. Equation of motion is expressed in terms of particle&#39;s optical properties, standardly used in optics for stationary particles.

Afsar Abbas

It has been proven recently that the Standard Model of particle physics has electric charge quantization built into it. It has also been shown by the author that there was no electric charge in the early universe. Further it is shown here that the restoration of the full Standard Model symmetry (as in the Early Universe) leads to the result that `time&#39;,

Henrique Bursztyn, Stefan Waldmann

In this paper we give a complete characterization of Morita equivalent star products on symplectic manifolds in terms of their characteristic classes: two star products $\star$ and $\star&#39;$ on $(M,ω)$ are Morita equivalent if and only if there exists a symplectomorphism $ψ:M\longrightarrow M$ such that the relative class $t(\star,ψ^*(\star&#39;))$ is $2

K. L. F. Bane, H. Hayano, K. Kubo, T. Naito

At the Accelerator Test Facility (ATF) at KEK intrabeam scattering (IBS) is a strong effect for an electron machine. It is an effect that couples all dimensions of the beam, and in April 2000, over a short period of time, all dimensions were measured as functions of current. In this report we derive a simple relation for the growth rates of emittances due to

Sultana N. Nahar

High resolution measurements of photoionization cross sections for atomic ions are now being made on synchrotron radiation sources. The recent measurements by Kjeldsen etal. (1999) showed good agreement between the observed resonance features and the the theoretical calculations in the close coupling approximation (Nahar 1995). However, there were several ob

John Lott

In the first part of this paper, given a smooth family of Dirac-type operators on an odd-dimensional closed manifold, we construct an abelian gerbe-with-connection whose curvature is the three-form component of the Atiyah-Singer families index theorem. In the second part of the paper, given a smooth family of Dirac-type operators whose index lies in the i-th

N. Pinto-Neto, R. Colistete

A massless scalar field without self interaction and string coupled to gravity is quantized in the framework of quantum cosmology using the Bohm-de Broglie interpretation. Gaussian superpositions of the quantum solutions of the corresponding Wheeler-DeWitt equation in minisuperspace are constructed. The bohmian trajectories obtained exhibit a graceful exit f

R. Gonzalez Felipe, F. R. Joaquim

In light of the recent solar and atmospheric neutrino data, we investigate the possibility of having an exactly degenerate spectrum for heavy right-handed Majorana neutrinos at the grand unification scale. The analysis is performed in the context of the minimal supersymmetric standard model with unbroken R-parity and extended with three heavy Majorana neutri

S. Nojiri, S. D. Odintsov

In frames of dS/CFT correspondence suggested by Strominger we calculate holographic conformal anomaly for dual euclidean CFT. The holographic renormalization group method is used for this purpose. It is explicitly demonstrated that two-dimensional and four-dimensional conformal anomalies (or corresponding central charges) have the same form as those obtained

A. L. Kataev, G. Parente, A. V. Sidorov

Using the results for the NNLO QCD corrections to anomalous dimensions of odd $xF_3$ Mellin moments and N$^3$LO corrections to their coefficient functions we improve our previous analysis of the CCFR'97 data for $xF_3$. The possibility of extracting from the fits of $1/Q^2$-corrections is analysed using three independent models,including infrared renormalon

Chung-Pei Ma, J. N. Fry

We derive fully nonlinear expressions for temperature fluctuations from the kinetic Sunyaev-Zeldovich (SZ) effect, the scattering of cosmic microwave background photons off hot electrons in bulk motion. Our result reproduces the Ostriker-Vishniac effect to second order in perturbation theory but contains nonlinear corrections to the electron velocities and d