December 2007 arXiv papers — page 42

H. Aratyn, J. F. Gomes, L. H. Ymai, A. H. Zimerman

Employing the Hirota's method, a class of soliton solutions for the N=2 super mKdV equations is proposed in terms of a single Grassmann parameter. Such solutions are shown to satisfy two copies of N=1 supersymmetric mKdV equations connected by nontrivial algebraic identities. Using the super Miura transformation, we obtain solutions of the N=2 super KdV

Delia Coculescu, Ashkan Nikeghbali

In this article, we define the notion of a filtration and then give the basic theorems on initial and progressive enlargements of filtrations.

Alexander K. Motovilov

We shortly recall the derivation of the Faddeev-Yakubovsky differential equations and point out their main advantages. Then we give a review of the numerical approaches used to solve the bound-state and scattering problems for the three- and four-body systems based on these equations. A particular attention is payed to the latest developments.

M. J. Perry, H. Lu, C. N. Pope

In an earlier paper we studied the infinite-dimensional symmetries of symmetric-space sigma models (SSMs) in a flat two-dimensional spacetime. Here, we extend our investigation to the case of two-dimensional SSMs coupled to gravity. These theories arise from the toroidal reduction of higher-dimensional gravity and supergravities to two dimensions. We constru

A. James, M. J. Plank

Heavy-tailed or power-law distributions are becoming increasingly common in biological literature. A wide range of biological data has been fitted to distributions with heavy tails. Many of these studies use simple fitting methods to find the parameters in the distribution, which can give highly misleading results. The potential pitfalls that can occur when

Owen W. Westbrook, Nancy Remage Evans, Scott J. Wolk, Vinay L. Kashyap

The high-resolution X-ray spectroscopy made possible by the 1999 deployment of the Chandra X-ray Observatory has revolutionized our understanding of stellar X-ray emission. Many puzzles remain, though, particularly regarding the mechanisms of X-ray emission from OB stars. Although numerous individual stars have been observed in high-resolution, realizing the

Mats Ehrnstrom, Gabriele Villari

Steady linear gravity waves of small amplitude travelling on a current of constant vorticity are found. For negative vorticity we show the appearance of internal waves and vortices, wherein the particle trajectories are not any more closed ellipses. For positive vorticity the situation resembles that of Stokes waves, but for large vorticity the trajectories

S. Schlamminger, K. -Y. Choi, T. A. Wagner, J. H. Gundlach

We used a continuously rotating torsion balance instrument to measure the acceleration difference of beryllium and titanium test bodies towards sources at a variety of distances. Our result Delta a=(0.6+/-3.1)x10^-15 m/s^2 improves limits on equivalence-principle violations with ranges from 1 m to infinity by an order of magnitude. The Eoetvoes parameter is

H. Meyer, J. P. Wittmer, T. Kreer, P. Beckrich

Following the Flory ideality hypothesis intrachain and interchain excluded volume interactions are supposed to compensate each other in dense polymer systems. Multi-chain effects should thus be neglected and polymer conformations may be understood from simple phantom chain models. Here we provide evidence against this phantom chain, mean-field picture. We an

A. Calamida, C. E. Corsi, G. Bono, P. B. Stetson

We present deep and precise photometry (F435, F625W, F658N) of Omega Cen collected with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST). We have identified ~ 6,500 white dwarf (WD) candidates, and the ratio of WD and Main Sequence (MS) star counts is found to be at least a factor of two larger than the ratio of CO-core WD cool

A. Calamida, C. E. Corsi, G. Bono, P. B. Stetson

We present deep and accurate photometry (F435W, F625W, F658N) of the Galactic Globular Cluster Omega Cen collected with the Advanced Camera for Surveys (ACS) on board the Hubble Space Telescope (HST). We identified ~ 6,500 white dwarf (WD)candidates and compared their radial distribution with that of Main Sequence (MS) stars. We found a mild evidence that yo

D0 Collaboration, V. Abazov

We present a study of four muon, four electron, and two muon two electron events using 1 fb^(-1) of data collected with the D0 detector at the Fermilab Tevatron p-barp Collider at sqrt(s) = 1.96 TeV. Requiring the lepton pair masses to be greater than 30 GeV, we observe one event, consistent with the expected background of 0.13 +- 0.03 events and with the pr

D0 Collaboration, V. M. Abazov

We present new results of the search for WH to lepton neutrino b b production in ppbar collisions at a center of mass energy of sqrt{s}=1.96 TeV, based on a dataset with integrated luminosity of 0.44 fb-1. We combine these new results with previously published searches by the D0 collaboration, for WH and ZH production analyzed in the MET b b final state, for

P. M. Ostrovsky, I. V. Gornyi, A. D. Mirlin

Recent successes in manufacturing of atomically thin graphite samples (graphene) have stimulated intense experimental and theoretical activity. The key feature of graphene is the massless Dirac type of low-energy electron excitations. This gives rise to a number of unusual physical properties of this system distinguishing it from conventional two-dimensional

R. Suarez, J. L. Orrell, C. E. Aalseth, T. W. Hossbach

Pulse-shape analysis of the ionization signals from germanium gamma-ray spectrometers is a method for obtaining information that can characterize an event beyond just the total energy deposited in the crystal. However, as typically employed, this method is data-intensive requiring the digitization, transfer, and recording of electronic signals from the spect

Marie Albenque, Jean-François Marckert

Stack-triangulations appear as natural objects when one wants to define some increasing families of triangulations by successive additions of faces. We investigate the asymptotic behavior of rooted stack-triangulations with $2n$ faces under two different distributions. We show that the uniform distribution on this set of maps converges, for a topology of loc

J. Bobin, Y. Moudden, J. -L. Starck, J. Fadili

In the last decade, the study of cosmic microwave background (CMB) data has become one of the most powerful tools to study and understand the Universe. More precisely, measuring the CMB power spectrum leads to the estimation of most cosmological parameters. Nevertheless, accessing such precious physical information requires extracting several different astro

Martin Zumsande, Mikko J. Alava, Alexander K. Hartmann

We present results on the first excited states for the random-field Ising model. These are based on an exact algorithm, with which we study the excitation energies and the excitation sizes for two- and three-dimensional random-field Ising systems with a Gaussian distribution of the random fields. Our algorithm is based on an approach of Frontera and Vives wh

Dmitri Nikshych

Given an action of a finite group G on a fusion category C we give a criterion for the category of G-equivariant objects in C to be group-theoretical, i.e., to be categorically Morita equivalent to a category of group-graded vector spaces. We use this criterion to answer affirmatively the question about existence of non group-theoretical semisimple Hopf alge

Juan Carlos Martinez, Lajos Soukup

We give full characterization of the sequences of regular cardinals that may arise as cardinal sequences of locally compact scattered spaces under GCH. The proofs are based on constructions of universal locally compact scattered spaces.

J. -P. Francoise, C. Piquet, A. Vidal

This article provides an example of fast-slow system such that most orbits remain as close as possible to the unstable manifold of the fast dynamics for an arbitrarily long time.

J. Gracia-Carpio, S. Garcia-Burillo, P. Planesas, A. Fuente

We present new observations made with the IRAM 30m telescope of the J=1-0 and 3-2 lines of HCN and HCO^+ used to probe the dense molecular gas content in a sample of 17 local luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs). These observations have allowed us to derive an updated version of the power law describing the correlation between the

Rachel E. Scherr

Systematic observations of student gestures can not only fill in gaps in students' verbal expressions, but can also offer valuable information about student ideas, including their source, their novelty to the speaker, and their construction in real time. This paper provides a review of the research in gesture analysis that is most relevant to physics edu

H. Beuther, A. Walsh

Characterizing rotation, infall and accretion disks around high-mass protostars is an important topic in massive star formation research. With the Australia Telescope Compact Array and the Very Large Array we studied a massive disk candidate at high angular resolution in ammonia (NH3(4,4) & (5,5)) tracing the warm disk but not the envelope. The observations

A. Sollima, C. Cacciari, A. A. Arkharov, V. M. Larionov

We present infrared JHK time series photometry of the variable star RR Lyr, that allow us to construct the first complete and accurate infrared light curves for this star. The derived mean magnitudes are <J>=6.74 +/- 0.02, <H>=6.60 +/- 0.03 and <K>=6.50 +/- 0.02. The <K> magnitude is used to estimate the reddening, the mass, the mean luminosity and temperatu

Alexander Burinskii

The combined Dirac-Kerr model of electron is suggested, in which electron has extended space-time structure of Kerr geometry, and the Dirac equation plays the role of a master equation controlling polarization of the Kerr congruence. The source contains a spinning disk bounded by a closed singular string of Compton size. It is conjectured that this Compton s

N. Schildermans, A. B. Kolton, R. Salenbien, V. I. Marconi

The interaction of externally applied currents with persistent currents induced by magnetic field in a mesoscopic triangle is investigated. As a consequence of the superposition of these currents, clear voltage rectification effects are observed. We demonstrate that the amplitude of the rectified signal strongly depends on the configurations of the current l

Mark M. Meerschaert, Erkan Nane, Yimin Xiao

Let $W^H=\{W^H(t), t \in \rr\}$ be a fractional Brownian motion of Hurst index $H \in (0, 1)$ with values in $\rr$, and let $L = \{L_t, t \ge 0\}$ be the local time process at zero of a strictly stable Lévy process $X=\{X_t, t \ge 0\}$ of index $1<α\leq 2$ independent of $W^H$. The $\a$-stable local time fractional Brownian motion $Z^H=\{Z^H(t), t \ge 0\}$ i

D. Drechsel, B. Pasquini, L. Tiator

The relativistic amplitudes of pion photo- and electroproduction are calculated by dispersion relations at constant t. Several sum rules and low-energy theorems for the threshold amplitudes are investigated within this technique. The continuation of the amplitudes to sub-threshold kinematics is shown to provide a unique framework to derive the low-energy con

Anthony Aguirre

Cosmological inflation, if it occurred, radically alters the picture of the `big bang&#39;, which would merely point to reheating at the end of inflation. Moreover, this reheating may be only local, so that inflation continues elsewhere and forever, continually spawning big-bang-like regions. This chapter reviews this idea of `eternal inflation&#39;, then fo

David Vercauteren, Henri Verschelde

In this paper we apply the formalism of local composite operators as developed by Verschelde et al. in combination with a constant chromomagnetic field as considered in the seventies by Savvidy and others. We find that a nonzero <A_μ^2> minimizes the vacuum energy, as in the case with no chromomagnetic field, and that the chromomagnetic field itself is near-

Jason Behrstock, Tadeusz Januszkiewicz, Walter Neumann

Suppose a group $G$ is quasi-isometric to a free product of a finite set $S$ of finitely generated abelian groups; let $S&#39;$ denote the set of ranks of the free abelian parts of the groups in $S$. Then $G$ is commensurable with the free product of $\Z$ with a $\Z^n$ for each $n$ occurring in $S&#39;$.

F. Hautmann, H. Jung

We summarize recent results on i) the use of u-pdf&#39;s in the Monte-Carlo simulation of hadronic final states at high-energy colliders, and ii) attempts to characterize u-pdf&#39;s with precision in terms of nonlocal operator matrix elements.

Maria Giovanna Dainotti, Maria Grazia Bernardini, Carlo Luciano Bianco, Letizia Caito

(shortened) We study the Gamma-Ray Burst (GRB) 060218: a particularly close source at z=0.033 with an extremely long duration, namely T_{90} ~ 2000 s, related to SN 2006aj. [...] I present the fitting time consuming procedure. In order to show its sensitivity I also present two examples of fits with the same value of B and different value of E_{e^\pm}^{tot}.

Ion I. Cotaescu, Crucean Cosmin

The lowest order contribution of the amplitude of Dirac-Coulomb scattering in de Sitter spacetime is calculated assuming that the initial and final states of the Dirac field are described by exact solutions of the free Dirac equation on de Sitter spacetime with a given energy and helicity. We find that the total energy is conserved in the scattering process.

Ernst Bauer, Rachid Belkhou, Salia Cherifi, Andrea Locatelli

The ferromagnetic to nonferromagnetic (&#945;-&#946;) phase transition in epitaxial MnAs layers on GaAs(100) is studied by x-ray magnetic circular dichroism and x-ray magnetic linear dichroism photoemission electron microscopy in order to elucidate the nature of the controversial nonferromagnetic state of &#946;-MnAs. In the coexistence region of the two pha

Boris Tomasik, Ivan Melo, Giorgio Torrieri, Igor Mishustin

We argue that fragmentation at hadronisation is likely scenario in ultrarelativistic nuclear collisions. In case of crossover phase transition it is driven by a singularity of the bulk viscosity. We claim that such a scenario can explain the ``HBT puzzle&#39;&#39; and can be identified by non-statistical differences between event-wise rapidity distributions

C. Güttler, T. Poppe, J. T. Wasson, J. Blum

In order to investigate the hypothesis that dust aggregates were transformed to meteoritic chondrules by nebular lightning, we exposed silicatic and metallic dust samples to electric discharges with energies of 120 to 500 J in air at pressures between 10 and 10^5 Pa. The target charges consisted of powders of micrometer-sized particles and had dimensions of

Rinaldo M. Colombo, Graziano Guerra

This paper proves the local well posedness of differential equations in metric spaces under assumptions that allow to comprise several different applications. We consider below a system of balance laws with a dissipative non local source, the Hille-Yosida Theorem, a generalization of a recent result on nonlinear operator splitting, an extension of Trotter fo

C. Testelin, F. Bernardot, G. Karczewski, M. Chamarro

We have studied the coherent spin dynamics in an oblique magnetic field of electrons localized on donors and placed in the middle of a single CdTe quantum well, by using a time-resolved optical technique: the photo-induced Faraday rotation. We showed that this dynamics is affected by a weak Overhauser field created via the hyperfine interaction of optically

Markus Bader

We use geometric invariant theory and the language of quivers to study compactifications of moduli spaces of linear dynamical systems. A general approach to this problem is presented and applied to two well known cases: We show how both Lomadze&#39;s and Helmke&#39;s compactification arises naturally as a geometric invariant theory quotient. Both moduli spac

Christina Goldschmidt, James B. Martin, Dario Spanò

Problem 1.5.7 from Pitman&#39;s Saint-Flour lecture notes: Does there exist for each n a fragmentation process (Π_{n,k}, 1 \leq k \leq n) taking values in the space of partitions of {1,2,...,n} such that Π_{n,k} is distributed like the partition generated by cycles of a uniform random permutation of {1,2,...,n} conditioned to have k cycles? We show that the

Z. Mikulasek, T. Graf, J. Krticka, J. Zverko

We analyzed uvby and Hp light curves of 19 well observed magnetic CP stars selected from the &#34;On-line database of photometric observations of mCP stars&#34; of which light curves in all the five colours were similar. We assumed that among these photometrically simply behaving (PSB) stars could be found such ones which have a single photometric spot. The

Prosenjit Bose, Paz Carmi, Mathieu Couture, Anil Maheshwari

We address the following problem: Given a complete $k$-partite geometric graph $K$ whose vertex set is a set of $n$ points in $\mathbb{R}^d$, compute a spanner of $K$ that has a ``small&#39;&#39; stretch factor and ``few&#39;&#39; edges. We present two algorithms for this problem. The first algorithm computes a $(5+ε)$-spanner of $K$ with O(n) edges in $O(n

Harold F. Levison, Alessandro Morbidelli, Christa Van Laerhoven, Rodney Gomes

We explore the origin and orbital evolution of the Kuiper belt in the framework of a recent model of the dynamical evolution of the giant planets, sometimes known as the Nice model. This model is characterized by a short, but violent, instability phase, during which the planets were on large eccentricity orbits. One characteristic of this model is that the p

Ágnes M. Backhausz, Vilmos Komornik, Tivadar Szilágyi

We present a simplified integral of functions of several variables. Although less general than the Riemann integral, most functions of practical interest are still integrable. On the other hand, the basic integral theorems can be obtained more quickly. We also give a characterization of the integrable functions and their primitives.

Maria Grazia Bernardini, Carlo Luciano Bianco, Letizia Caito, Maria Giovanna Dainotti

On the basis of the recent understanding of GRB050315 and GRB060218, we return to GRB970228, the first Gamma-Ray Burst (GRB) with detected afterglow. We proposed it as the prototype for a new class of GRBs with &#34;an occasional softer extended emission lasting tenths of seconds after an initial spikelike emission&#34;. Detailed theoretical computation of t

O. Boulle, V. Cros, J. Grollier, L. G. Pereira

The spin transfer torque (STT) can lead to steady precession of magnetization without any external applied field in magnetic spin valve where the magnetic layer have very different spin diffusion length. This effect is associated with an unusual angular dependence of the STT, called &#34;wavy&#34; (WAD-STT), predicted in the frame of diffusive models of spin

Akihiko Nakajima, Kunihiko Kaneko

In multicellular organisms, several cell states coexist. For determining each cell type, cell-cell interactions are often essential, in addition to intracellular gene expression dynamics. Based on dynamical systems theory, we propose a mechanism for cell differentiation with regulation of populations of each cell type by taking simple cell models with gene e

Joydeep Bagchi, Gopal-Krishna, Marita Krause, Santosh Joshi

We report the discovery of a very unusual, highly asymmetric radio galaxy whose radio jet, the largest yet detected, emits strongly polarized synchrotron radiation and can be traced all the way from the galactic nucleus to the hot spot located ~440 kpc away. This jet emanates from an extremely massive black hole (>10^9 solar mass) and forms a strikingly comp

B. I. Ermolaev, S. I. Troyan

In the QCD context, the non-singlet structure functions of u and d -quarks are identical, save the initial quark densities. Electroweak radiative corrections, being flavor-dependent, bring further difference between the non-singlets. This difference is calculated in the double-logarithmic approximation and the impact of the electroweak corrections on the non

R. Schneider, R. Salvaterra, T. Roy Choudhury, A. Ferrara

We use a semi-analytical model to study the impact of reionization, and the associated radiative feedback, on galaxy formation. Two feedback models have been considered: (i) a standard prescription, according to which star formation is totally suppressed in galaxies with circular velocity below a critical threshold (model CF06) and (ii) a characterization ba

Francesco Coradeschi, Stefania De Curtis, Daniele Dominici, José R. Pelaez

We show how translational invariance can be broken by the vacuum that drives the spontaneous symmetry breaking of extra-dimensional extensions of the Standard Model, when delta-like interactions between brane and bulk scalar fields are present. We explicitly build some examples of vacuum configurations, which induce the spontaneous symmetry breaking, and hav

S. Verley, F. Combes, L. Verdes-Montenegro, G. Bergond

Star formation depends strongly on both the local environment of galaxies and the internal dynamics of the interstellar medium. To disentangle the two effects, we obtained, in the framework of the AMIGA project, Halpha and Gunn r photometric data for more than 200 spiral galaxies lying in very low-density regions of the local Universe. We characterise the Ha

Ph. Brax, Stephen C. Davis, M. Postma

A spectral index n_s < 0.95 appears to be a generic prediction of racetrack inflation models. Reducing a general racetrack model to a single-field inflation model with a simple potential, we obtain an analytic expression for the spectral index, which explains this result. By considering the limits of validity of the derivation, possible ways to achieve highe

S. Verley, L. K. Hunt, E. Corbelli, C. Giovanardi

Combining the relative vicinity of the Local Group spiral galaxy M33 with the Spitzer images, we investigate the properties of infrared (IR) emission sites and assess the reliability of the IR emission as a star formation tracer. We compared the photometric results for several samples of three known types of discrete sources (HII regions, supernovae remnants

Jean-Alexandre Long, Vincent Daanen, Alexandre Moreau-Gaudry, Jocelyne Troccaz

OBJECTIVE: This study evaluated the accuracy in localisation and distribution of real-time three-dimensional (4-D) ultrasound-guided biopsies on a prostate phantom. METHODS: A prostate phantom was created. A three-dimensional real-time ultrasound system with a 5.9MHz probe was used, making it possible to see several reconstructed orthogonal viewing planes in

M. Widom, M. Mihalkovic

The crystal structure of boron is unique among chemical elements, highly complex, and imperfectly known. Experimentalists report the beta-rhombohedral (black) form is stable over all temperatures from absolute zero to melting. However, early calculations found its energy to be greater than the energy of the alpha-rhombohedral (red) form, implying beta cannot

P. Faccioli, M. Cristoforetti, M. C. Tichy, M. Traini

We review our recent study of the role played by the chiral interactions induced by instantons, in the lowest-lying sector of the light hadron spectrum. We discuss how the ordering of the lowest meson and baryon excitations is explained by the structure of the instanton-induced quark-quark and gluon-gluon interaction. We focus on the pion, nucleon, vector- a

Jean-Philippe Chancelier

In this paper we study iterative algorithms for finding a common element of the set of fixed points of $κ$-strict pseudocontractions or finding a solution of a variational inequality problem for a monotone, Lipschitz continuous mapping. The last problem being related to finding fixed points of pseudocontractions. These algorithms were already studied in [G.L

Renaud Leplaideur, Benoit Saussol

For Axiom A diffeomorphisms and equilibrium states, we prove a Large deviations result for the sequence of successive return times into a fixed Borel set, under some assumption on the boundary. Our result relies on and extends the work by Chazottes and Leplaideur who considered cylinder sets of a Markov partition.

F. Hautmann, D. E. Soper

We discuss the operator relation that connects the renormalized quark distribution in the MSbar scheme with the Wilson-line correlator representing dipole scattering in the s-channel picture.

Marc Autord

Gröbner bases, in their noncommutative version, and word reversing are methods for solving the word problem of a presented monoid, and both rely on iteratively completing the initial list of relations. Simple examples may suggest to conjecture that both completion procedures are closely related. Here we disprove this conjecture by exhibiting families of pres

Z. Mikulasek, J. Krticka, J. Zverko, G. W. Henry

We study the long-term light and spectral variations in the He-strong magnetic chemically peculiar star HD 37776 (V901 Ori) to search for changes of its 1.5387 d period in 1976-2007. We analyze all published photometric observations and spectrophotometry in the HeI 4026 A line. The data were supplmented with 506 new (U)VB observations obtained during the las

J. M. Wang, Y. -M. Chen, C. -S. Yan, C. Hu

Episodic activity of quasars is driving growth of supermassive black holes (SMBHs) via accretion of baryon gas. In this Letter, we develop a simple method to analyse the duty cycle of quasars up to redshift $z\sim 6$ universe from luminosity functions (LFs). We find that the duty cycle below redshift $z\sim 2$ follows the cosmic history of star formation rat

Catalin Badea, Bernhard Beckermann, Michel Crouzeix

We prove that if two closed disks X_1 and X_2 of the Riemann sphere are spectral sets for a bounded linear operator A on a Hilbert space, then the intersection X_1\cap X_2 is a complete (2+2/\sqrt{3})-spectral set for A. When the intersection of X_1 and X_2 is an annulus, this result gives a positive answer to a question of A.L. Shields (1974).

E. Celeghini, A. Ballesteros, M. A. del Olmo

The ``local&#39;&#39; structure of a quantum group G_q is currently considered to be an infinite-dimensional object: the corresponding quantum universal enveloping algebra U_q(g), which is a Hopf algebra deformation of the universal enveloping algebra of a n-dimensional Lie algebra g=Lie(G). However, we show how, by starting from the generators of the underl

S. Gabani, S. Matas, P. Priputen, K. Flachbart

Magnetic structure of single crystalline TmB4 has been studied by magnetization, magnetoresistivity and specific heat measurements. A complex phase diagram with different antiferromagnetic (AF) phases was observed below TN1 = 11.7 K. Besides the plateau at half-saturated magnetization (1/2 MS), also plateaus at 1/9, 1/8 and 1/7 of MS were observed as functio

F. A. Baroncini, E. Pace, G. Salme`

We present a preliminary calculation of the electromagnetic form factors of $^3$He and $^3$H, performed within the Light-Front Hamiltonian Dynamics. Relativistic effects show their relevance even at the static limit, increasing at higher values of momentum transfer, as expected.

Daniela Villegas, Markus Kissler-Patig, Andrés Jordán, Paul Goudfrooij

We present the results of a study of the globular cluster systems of 6 massive spiral galaxies, originally cataloged as low surface brightness galaxies but here shown to span a wide range of central surface brightness values, including two intermediate to low surface brightness galaxies. We used the Advanced Camera for Surveys on board HST to obtain photomet

Jiagang Yang

We show that for a $C^1$ residual subset of diffeomorphisms far away from homoclinic tangency, the stable manifolds of periodic points cover a dense subset of the ambient manifold. This gives a partial proof to a conjecture of C. Bonatti.

Jiagang Yang

We show that for a $C^1$ residual subset of diffeomorphisms far away from tangency, every non-trivial chain recurrent class that is accumulated by sources ia a homoclinic class contains periodic points with index 1 and it&#39;s the Hausdorff limit of a family of sources.

Bernat Corominas-Murtra, José F. F. Mendes, Ricard V. Solé

We analytically explore the scaling properties of a general class of nested subgraphs in complex networks, which includes the $K$-core and the $K$-scaffold, among others. We name such class of subgraphs $K$-nested subgraphs due to the fact that they generate families of subgraphs such that $...S_{K+1}({\cal G})\subseteq S_K({\cal G})\subseteq S_{K-1}({\cal G

M. F. Nieva, N. Przybilla

We present a state-of-the-art analysis technique able to simultaneously reproduce the entire H and He spectra of OB-type stars in the visual and the near-IR and to derive highly accurate metal abundances (so far C and N). The spectrum synthesis relies on a hybrid non-LTE approach involving our most recent model atoms. Accurate atmospheric parameters, with re

Eduardo Bravo, Domingo Garcia-Senz

Deflagration models poorly explain the observed diversity of SNIa. Current multidimensional simulations of SNIa predict a significant amount of, so far unobserved, carbon and oxygen moving at low velocities. It has been proposed that these drawbacks can be resolved if there is a sudden jump to a detonation (delayed detonation), but this kind of models has be

L. Cunqueiro, J. Dias de Deus, E. G. Ferreiro, C. Pajares

In the framework of percolation of strings, the transverse momentum distributions in AA and hh collisions at all centralities and energies follow a universal behavior. The width of these distributions is related to the width of the distribution of the size of the clusters formed from the overlapping of the produced strings. The difference between the distrib

Roumen Anguelov

The ring operations and the metric on $C(X)$ are extended to the set $\mathbb{H}_{nf}(X)$ of all nearly finite Hausdorff continuous interval valued functions and it is shown that $\mathbb{H}_{nf}(X)$ is both rationally and topologically complete. Hence, the rings of quotients of $C(X)$ as well as their metric completions are represented as rings of Hausdorff

Kayhan Ulker, Baris Yapiskan

All order Seiberg--Witten maps of gauge parameter, gauge field and matter fields are given as a closed recursive formula. These maps are obtained by analyzing the order by order solutions of the gauge consistency and equivalence conditions as well as by directly solving Seiberg-Witten differential equations. The explicit third order non-abelian and fourth or

Yasuhiro Tada, Norio Kawakami, Satoshi Fujimoto

We study the pairing symmetry of the noncentrosymmetric heavy fermion superconductors CeRhSi$_3$ and CeIrSi$_3$ under pressures, which are both antiferromagnets at ambient pressure. We solve the Eliashberg equation by means of the random phase approximation and find that the mixed state of extended s-wave and p-wave rather than the $d+f$ wave state could be

Naoko Kifune, Jisuke Kubo, Alexander Lenz

A supersymmetric extension of the standard model based on the discrete $Q_6$ family symmetry is considered, and we investigate flavor-changing neutral current (FCNC) processes, especially those mediated by heavy flavor-changing neutral Higgs bosons. Because of the family symmetry the number of the independent Yukawa couplings is smaller than that of the obse

T. Baehr-Jones, M. Hochberg, A. Scherer

Silicon is an extremely attractive material platform for integrated optics at telecommunications wavelengths, particularly for integration with CMOS circuits. Developing detectors and electrically pumped lasers at telecom wavelengths are the two main technological hurdles before silicon can become a comprehensive platform for integrated optics. We report on

M. Cortesi

Selective accumulation of B-10 compound in tumour tissue is a fundamental condition for the achievement of BNCT (Boron Neutron Capture Therapy), since the effectiveness of therapy irradiation derives just from neutron capture reaction of B-10. Hence, the determination of the B-10 concentration ratio, between tumour and healthy tissue, and a control of this r

E. Del Monte, M. Feroci, L. Pacciani, Y. Evangelista

GRB 070724B is the first Gamma Ray Burst localized by SuperAGILE, the hard X-ray monitor aboard the AGILE satellite. The coordinates of the event were published $\sim 19$ hours after the trigger. The Swift X-Ray Telescope pointed at the SuperAGILE location and detected the X-ray afterglow inside the SuperAGILE error circle. The AGILE gamma-ray Tracker and Mi

Ioannis Antonellis, Hector Garcia-Molina, Chi-Chao Chang

We focus on the problem of query rewriting for sponsored search. We base rewrites on a historical click graph that records the ads that have been clicked on in response to past user queries. Given a query q, we first consider Simrank as a way to identify queries similar to q, i.e., queries whose ads a user may be interested in. We argue that Simrank fails to

W. M. Sun

We exploit the quantum coherence between pair-produced D0 and D0bar in psi(3770) decays to study charm mixing and to make a first measurement of the relative strong phase \delta between D0 -> K+pi- and D0bar -> K+pi-. Using 281 pb^-1 of e+e- collision data collected with the CLEO-c detector at E_cm=3.77 GeV, as well as branching fraction input from other exp

J. P. Stott, A. C. Edge, G. P. Smith, A. M. Swinbank

We investigate the near infrared evolution of brightest cluster galaxies (BCGs) from a sample of rich galaxy clusters since z=1. By employing an X-ray selection of Lx>1e44 erg s-1 we limit environmental effects by selecting BCGs in comparably high density regions. We find a positive relationship between X-ray and near-infrared luminosity for BCGs in clusters

Carlo Luciano Bianco, Maria Grazia Bernardini, Letizia Caito, Maria Giovanna Dainotti

In the &#34;fireshell&#34; model we define a &#34;canonical GRB&#34; light curve with two sharply different components: the Proper-GRB (P-GRB), emitted when the optically thick fireshell of electron-positron plasma originating the phenomenon reaches transparency, and the afterglow, emitted due to the collision between the remaining optically thin fireshell a

Victor Ivrii

I derive sharp semiclassical asymptotics of \int |e_h(x,y,0)|^2ω(x,y)dxdy where e_h(x,y,τ) is the Schwartz kernel of the spectral projector of Magnetic Schroedinger operator and ω(x,y) is singular as x=y. I also consider asymptotics of more general expressions.

Nikodem Szpak, Piotr Bizoń, Tadeusz Chmaj, Andrzej Rostworowski

We derive the exact late-time asymptotics for small spherically symmetric solutions of nonlinear wave equations with a potential. The dominant tail is shown to result from the competition between linear and nonlinear effects.

Eero Saksman, Kristian Seip

We study the boundary behavior of functions in the Hardy spaces HD^p for ordinary Dirichlet series. Our main result, answering a question of H. Hedenmalm, shows that the classical F. Carlson theorem on integral means does not extend to the imaginary axis for functions in HD^\infty, i.e., for ordinary Dirichlet series in H^\infty of the right half-plane. We d

S. V. Goloskokov

We study light vector meson electroproduction at small $x$ within the generalized parton distributions (GPDs) model. The modified perturbative approach is used, where the quark transverse degrees of freedom in the vector meson wave function and hard subprocess are considered. Our results on the cross section and spin observables are in good agreement with ex

Mats Ehrnstrom

We investigate steady symmetric gravity water waves on finite depth. For non-positive vorticity it is shown that the particles display a mean forward drift, and for a class of waves we prove that the size of this drift is strictly increasing from bottom to surface. We also provide detailed information concerning the streamlines and the particle trajectories.

Heiko Scheit, Alexandra Gade, Thomas Glasmacher, Tohru Motobayashi

In a recent publication (Bertulani et al., PLB 650 (2007) 233 and arXiv:0704.0060v2) the validity of analysis methods used for intermediate-energy Coulomb excitation experiments was called into question. Applying a refined theory large corrections of results in the literature seemed needed. We show that this is not the case and that the large deviations obse

R. Nordon, E. Behar

The Solar First Ionization Potential (FIP) effect, where low-FIP elements are enriched in the corona relative to the photosphere, while high-FIP abundances remain unchanged, has been known for a long while. High resolution X-ray spectroscopy has revealed that active stellar coronae show an opposite effect, which was labeled the Inverse-FIP (IFIP) effect. The

S. Sciortino

Chandra and XMM-Newton have surveyed several nearby star forming regions and have greatly advanced our knowledge of X-ray emission from Young Stellar Objects (YSOs). After briefly reviewing it I discuss the advancements in this research field that could be possible with Simbol-X unique imaging capability in the hard X-ray bandpass.

Zs. Hurta, J. Jurcsik, B. Szeidl, A. Sodor

RV UMa is one of the RRab stars showing regular large amplitude light curve modulation. Extended photoelectric observations of RV UMa obtained at the Konkoly Observatory were published by Kanyo (1976). The analysis of the data was published by Kovacs (1995). After detecting an error in the reduction procedure of the published Konkoly data, corrected photomet

Ilki Kim, Guenter Mahler

In the classical limit no work is needed to couple a system to a bath with sufficiently weak coupling strength (or with arbitrarily finite coupling strength for a linear system) at the same temperature. In the quantum domain this may be expected to change due to system-bath entanglement. Here we show analytically that the work needed to couple a single linea

J. E. Palomar Tarancon

The author states an exact expression of the distribution of primes.

M. Guedel, K. R. Briggs, T. Montmerle, M. Audard

Most stars form as members of large associations within dense, very cold (10-100 K) molecular clouds. The nearby giant molecular cloud in Orion hosts several thousand stars of ages less than a few million years, many of which are located in or around the famous Orion Nebula, a prominent gas structure illuminated and ionized by a small group of massive stars

Ling Qi, Jean-Paul Chapel, Jean-Christophe Castaing, Jerome Fresnais

We report the co-assembly and adsorption properties of coacervate complexes made from polyelectrolyte-neutral block copolymers and oppositely charged nanocolloids. The nanocolloids put under scrutiny were ionic surfactant micelles and highly charged 7 nm cerium oxide (CeO2) nanoparticles. Static and dynamic light scattering was used to investigate the micros