September 2009 arXiv papers — page 49

A. Jesche, C. Krellner, M. de Souza, M. Lang

Single crystals of CeFeAsO, large enough to study the anisotropy of the magnetic properties, were grown by an optimized Sn-flux technique. The high quality of our single crystals is apparent from the highest residual resistivity ratio, RRR = 12, reported among undoped RFeAsO compounds (R=rare earth) as well as sharp anomalies in resistivity, specific heat, C

Kimmo Kainulainen, Valerio Marra

We study the weak gravitational lensing effects caused by a stochastic distribution of dark matter halos. We develop a simple approach to calculate the magnification probability distribution function which allows us to easily compute the magnitude bias and dispersion for an arbitrary data sample and a given universe model. As an application we consider the e

Carlos Nunez, Maurizio Piai, Antonio Rago

We consider the VEV of Wilson loop operators by studying the behavior of string probes in solutions of Type IIB string theory generated by Nc D5 branes wrapped on an internal manifold. In particular, we focus on solutions to the background equations that are dual to field theories with a walking gauge coupling as well as for flavored systems. We present in d

G. Bihain, R. Rebolo, M. R. Zapatero Osorio, V. J. S. Béjar

Free-floating substellar candidates with estimated theoretical masses of as low as ~5 Jupiter masses have been found in the ~3 Myr old sigma Orionis open cluster. As the overlap with the planetary mass domain increases, the question of how these objects form becomes important. The determination of their number density and whether a mass cut-off limit exists

C. Gougoussis, J. -P. Rueff, M. Calandra, M. d'Astuto

Using high resolution x-ray absorption spectroscopy and state-of-the-art electronic structure calculations we demonstrate that the pre-edge region at the Cu K-edge of high T$_c$ cuprates is composed of several excitationsinvisible in standard X-ray absorption spectra. We consider in detail the case of Ca$_{2-x}$CuO$_2$Cl$_2$ and show that the many pre-edge e

Zacky Choo, Wajid Mannan, Rubén J. Sánchez-García, Victor P. Snaith

This paper has been merged with arXiv:0908.3765

Brendan Lucier, Allan Borodin

We consider auctions in which greedy algorithms, paired with first-price or critical-price payment rules, are used to resolve multi-parameter combinatorial allocation problems. We study the price of anarchy for social welfare in such auctions. We show for a variety of equilibrium concepts, including Bayes-Nash equilibrium and correlated equilibrium, the resu

Nitin Nitsure

For any flat family of pure-dimensional coherent sheaves on a family of projective schemes, the Harder-Narasimhan type (in the sense of Gieseker semistability) of its restriction to each fiber is known to vary semicontinuously on the parameter scheme of the family. This defines a stratification of the parameter scheme by locally closed subsets, known as the

Armindo Costa, Michael Farber

In this paper we study topological invariants of a class of random groups. Namely, we study right angled Artin groups associated to random graphs and investigate their Betti numbers, cohomological dimension and topological complexity. The latter is a numerical homotopy invariant reflecting complexity of motion planning algorithms in robotics. We show that th

B. Mosser, T. Appourchaux

The observations carried out by the space missions CoRoT and Kepler provide a large set of asteroseismic data. Their analysis requires an efficient procedure first to determine if the star is reliably showing solar-like oscillations, second to measure the so-called large separation, third to estimate the asteroseismic information that can be retrieved from t

Ludvig Lizana, Tobias Ambjornsson, Alessandro Taloni, Eli Barkai

In this study we derive a single-particle equation of motion, from first-principles, starting out with a microscopic description of a tracer particle in a one-dimensional many-particle system with a general two-body interaction potential. Using a new harmonization technique, we show that the resulting dynamical equation belongs to the class of fractional Lan

Antoine Delon, Irène Wang, Emeline Lambert, Silva Lerbs-Mache

Determining the number of fluorescent entities that are coupled to a given molecule (DNA, protein, etc.) is a key point of numerous biological studies, especially those based on a single molecule approach. Reliable methods are important, in this context, not only to characterize the labeling process, but also to quantify interactions, for instance within mol

M. Majumder, K. Ghoshray, A. Ghoshray, B. Bandyopadhyay

dc magnetization and 31^P spin lattice relaxation rate in the polycrystalline sample of LaCoPO suggest a spin fluctuation dominated ferromagnetically ordered state. Moreover, NMR data clearly indicate a crossover from 2D to 3D spin fluctuations across T_C. In contrast to isotropic hyperfine field, H_hf at the 31^P site in LaFePO, H_hf is anisotropic in LaCoP

V. Gorini, A. Yu. Kamenshchik, U. Moschella, O. F. Piattella

We investigate the Tolman-Oppenheimer-Volkoff equations for the generalized Chaplygin gas with the aim of extending the findings of V. Gorini, U. Moschella, A. Y. Kamenshchik, V. Pasquier, and A. A. Starobinsky [Phys. Rev. D {\bf 78}, 064064 (2008)]. We study both the standard case, where we reproduce some previous results, and the phantom case. In the phant

S. S. Komissarov, M. V. Barkov

The very first stars in the Universe can be very massive, up to $10^3M_\odot$. If born in large numbers, such massive stars can have strong impact on the subsequent star formation, producing strong ionising radiation and contaminating the primordial gas with heavy elements. They would leave behind massive black holes that could act as seeds for growing super

Aleks Kleyn

In this paper I explore the set of quaternion algebras over field. Quaternion algebra E(C,-1,-1) is isomorphic to tensor product of complex field C and quaternion algebra H=E(R,-1,-1). Considered two sets of quaternion functions, which satisfy to equation similar to Cauchy-Riemann equation for a complex function.

An Huang

We explore some axioms of divergent series and their relations with conformal field theory. As a consequence we obtain another way of calculating $L(0,χ)$ and $L(-1,χ)$ for $χ$ being a Dirichlet character. We hope this discussion is also of interest to physicists doing renormalization theory for a reason indicated in the Introduction section. We introduce a

R. Hoehmann, U. Kuhl, H. -J. Stoeckmann, L. Kaplan

Microwave transport experiments have been performed in a quasi-two-dimensional resonator with randomly distributed scatterers, each mimicking an $r^{-2}$ repulsive potential. Analysis of both stationary wave fields and transient transport shows large deviations from Rayleigh's law for the wave height distribution, which can only partially be described by

Ulrich Bunke

The present paper is a contribution to categorial index theory. Its main result is the calculation of the Pfaffian line bundle of a certain family of real Dirac operators as an object in the category of line bundles. Furthermore, it is shown how string structures give rise to trivialisations of that Pfaffian.

S. Boudreault, C. A. L. Bailer-Jones

We present the stellar and substellar mass function of the open cluster IC2391, plus its radial dependence, and use this to put constraints on the formation mechanism of brown dwarfs. Our multiband optical and infrared photometric survey with spectroscopic follow-up covers 11 square degrees, making it the largest survey of this cluster to date. We observe a

David L. Wiltshire

We examine the properties of a recently proposed observationally viable alternative to homogeneous cosmology with smooth dark energy, the timescape cosmology. In the timescape model cosmic acceleration is realized as an apparent effect related to the calibration of clocks and rods of observers in bound systems relative to volume-average observers in an inhom

Shengjun Wu, Klaus Mølmer

We derive schemes to measure the so-called weak values of quantum system observables by coupling of the system to a qubit meter system. We highlight, in particular, the meaning of the imaginary part of the weak values, and show how it can be measured directly on equal footing with the real part of the weak value. We present compact expressions for the weak v

N. Sahakyan, H. Azizbekyan, H. Ishkhanyan, R. Sokhoyan

In the framework of a basic semiclassical time-dependent nonlinear two-state problem, we study the weak coupling limit of the nonlinear Landau-Zener transition at coherent photo- and magneto-association of an atomic Bose-Einstein condensate. Using an exact third-order nonlinear differential equation for the molecular state probability, we develop a variation

Francesco Ciccarello, Mauro Paternostro, G. Massimo Palma, M. Zarcone

We present a protocol that sets maximum stationary entanglement between remote spins through scattering of mobile mediators without initialization, post-selection or feedback of the mediators' state. No time-resolved tuning is needed and, counterintuitively, the protocol generates two-qubit singlet states even when classical mediators are used. The mecha

Nobuhiro Uekusa

We study quantum loop corrections to two-point functions and extraction of physical quantities in a five-dimensional $\phi^4$ theory on an orbifold. At two-loop level, we find that divergence for quartic derivative terms of $(p^2)^2$ appear as Lagrangian terms in the bulk. The counterterms are needed and these terms make propagators have two poles. With this

Vladimir G. Plekhanov

This paper is brief review of three aspects of the isotope - based quantum information: computation, teleportation and cryptography. Our results demonstrate not only that entanglement exists in elementary excitation of isotope - mixed solids but also it can be used for quantum information processing.

Jonathan M. Bloom

To a link L in the 3-sphere, we associate a spectral sequence whose E^2 page is the reduced Khovanov homology of L and which converges to a version of the monopole Floer homology of the branched double cover. The pages E^k for k > 1 depend only on the mutation equivalence class of L. We define a mod 2 grading on the spectral sequence which interpolates betwe

Sabin Cautis

We construct natural equivalences between derived categories of coherent sheaves on the local models for stratified Mukai or Atiyah flops (of type A).

Binay Bhattacharya, Arijit Bishnu, Otfried Cheong, Sandip Das

We discuss a method of finding skyline or non-dominated sites in a set $P$ of $n$ point sites with respect to a set $S$ of $m$ points. A site $p \in P$ is non-dominated if and only if for each $q \in P \setminus \{p\}$, there exists at least one point $s \in S$ that is closer to $p$ than to $q$. We reduce this problem of determining non-dominated sites to th

J. Z. Bernad, M. Jaaskelainen, U. Zuelicke

We use linear-response theory to evaluate the frequency-dependent conductivity of a system subject to a continuous quantum measurement of the current. Application of this formalism to graphene yields a consistent framework for discussing nonuniversal values of its minimal conductivity.

Pierre Albin, Clara L. Aldana, Frédéric Rochon

On compact surfaces with or without boundary, Osgood, Phillips and Sarnak proved that the maximum of the determinant of the Laplacian within a conformal class of metrics with fixed area occurs at a metric of constant curvature and, for negative Euler characteristic, exhibited a flow from a given metric to a constant curvature metric along which the determina

D. J. Saunders, S. J. Jones, H. M. Wiseman, G. J. Pryde

Entanglement is the defining feature of quantum mechanics, and understanding the phenomenon is essential at the foundational level and for future progress in quantum technology. The concept of steering was introduced in 1935 by Schrödinger as a generalization of the Einstein-Podolsky-Rosen (EPR) paradox. Surprisingly, it has only recently been formalized as

Joel Veness, Kee Siong Ng, Marcus Hutter, William Uther

This paper introduces a principled approach for the design of a scalable general reinforcement learning agent. Our approach is based on a direct approximation of AIXI, a Bayesian optimality notion for general reinforcement learning agents. Previously, it has been unclear whether the theory of AIXI could motivate the design of practical algorithms. We answer

Sergey Shadrin, Dimitri Zvonkine

We discuss an analog of the Givental group action for the space of solutions of the commutativity equation. There are equivalent formulations in terms of cohomology classes on the Losev-Manin compactifications of genus 0 moduli spaces; in terms of linear algebra in the space of Laurent series; in terms of differential operators acting on Gromov-Witten potent

A. W. Mason, Andreas Schweizer

We extend some algebraic properties of the classical modular group SL_2(Z) to equivalent groups in the theory of Drinfeld modules, in particular properties which are important in the theory of modular curves. We study cusp amplitudes and the level of a (congruence) subgroup of SL_2(D) for any Dedekind domain D, as ideals of D. In particular, we extend a rema

Shangbin Cui, Carlos E. Kenig

In this paper we study weak continuity of the dynamical systems for the KdV equation in H^{-3/4}(R) and the modified KdV equation in H^{1/4}(R). This topic should have significant applications in the study of other properties of these equations such as finite time blow-up and asymptotic stability and instability of solitary waves. The spaces considered here

Shangbin Cui, Carlos E. Kenig

In this paper we show that the floow map of the Benjamin-Ono equation on the line is weakly continuous in L2(R), using "local smoothing" estimates. L2(R) is believed to be a borderline space for the local well-posedness theory of this equation. In the periodic case, Molinet [27] has recently proved that the flow map of the Benjamin-Ono equation is no

Neil Barnaby, Zhiqi Huang

In a variety of inflation models the motion of the inflaton may trigger the production of some non-inflaton particles during inflation, for example via parametric resonance or a phase transition. Particle production during inflation leads to observables in the cosmological fluctuations, such as features in the primordial power spectrum and also nongaussianit

Lan Luan, Ophir M. Auslaender, Thomas M. Lippman, Clifford W. Hicks

We use magnetic force microscopy (MFM) and scanning SQUID susceptometry to measure the local superfluid density $ρ_{s}$ in Ba(Fe$_{0.95}$Co$_{0.05}$)$_2$As$_2$ single crystals from 0.4 K to the critical temperature $T_c=18.5$ K. We observe that the penetration depth $λ$ varies about ten times more slowly with temperature than previously published, with a dep

Alexei M. Veneziani, Tiago Pereira, Domingos H. U. Marchetti

We investigate the eigenvalues statistics of ensembles of normal random matrices when their order N tends to infinite. In the model the eigenvalues have uniform density within a region determined by a simple analytic polynomial curve. We study the conformal deformations of normal random ensembles to Hermitian random ensembles and give sufficient conditions f

R. Meijerink, K. M. Pontoppidan, G. A. Blake, D. R. Poelman

The study of warm molecular gas in the inner regions of protoplanetary disks is of key importance for the study of planet formation and especially for the transport of H2O and organic molecules to the surfaces of rocky planets/satellites. Recent Spitzer observations have shown that the mid-infrared spectra of protoplanetary disks are covered in emission line

P. W. A. Roming, T. A. Pritchard, P. J. Brown, S. T. Holland

We present the UV, optical, X-ray, and radio properties of the Type IIb SN 2008ax discovered in NGC 4490. The observations in the UV are one of the earliest of a Type IIb supernova (SN). On approximately day four after the explosion, a dramatic upturn in the u and uvw1 (lambda_c = 2600 Angstroms) light curves occurred after an initial rapid decline which is

Vasily E. Tarasov

We prove a generalization of the quantum Markovian equation for observables. In this generalized equation, we use superoperators that are fractional powers of completely dissipative superoperators. We prove that the suggested superoperators are infinitesimal generators of completely positive semigroups and describe the properties of this semigroup. We solve

L. Del Rio, E. Altshuler, S. Niratisairak, O. Haugen

Using fluorescent microthermal imaging we have investigated the origin of "two-step" behavior in I-V curves for a current-carrying YBa_2Cu_3O_x superconducting bridge. High resolution temperature maps reveal that as the applied current increases the first step in the voltage corresponds to local dissipation (hot spot), whereas the second step is asso

Weiwei Zhu, Victoria M. Kaspi, Majorie E. Gonzalez, Andrew G. Lyne

Using observations made with the XMM-Newton Observatory, we report the first X-ray detection of the high magnetic field radio pulsar PSR B1916+14. We show that the X-ray spectrum of the pulsar can be well fitted with an absorbed blackbody with temperature in the range of 0.08-0.23 keV, or a neutron star hydrogen atmosphere model with best-fit effective tempe

E. Furlan, D. M. Watson, M. K. McClure, P. Manoj

We analyze samples of Spitzer Infrared Spectrograph (IRS) spectra of T Tauri stars in the Ophiuchus, Taurus, and Chamaeleon I star-forming regions, whose median ages lie in the <1 to 2 Myr range. The median mid-infrared spectra of objects in these three regions are similar in shape, suggesting, on average, similar disk structures. When normalized to the same

W. N. Brandt, G. Chartas, S. C. Gallagher, R. R. Gibson

We briefly describe some recent observational results, mainly at X-ray wavelengths, on the winds of luminous active galactic nuclei (AGNs). These winds likely play a significant role in galaxy feedback. Topics covered include (1) Relations between X-ray and UV absorption in Broad Absorption Line (BAL) and mini-BAL quasars; (2) X-ray absorption in radio-loud

Jason T. Wright

As of August 2008, over 30 multiple exoplanet systems are known, and 28% of stars with planets show significant evidence of a second companion. I briefly review these 30 systems individually, broadly grouping them into five categories: 1) systems with 3 or more giant (Msini > 0.2 M_Jup) planets, 2) systems with two giant planets in mean motion resonance (MMR

Katie S. Quertermous

For 0 < s < 1, let phi_s(z)=sz+(1-s). We investigate the unital C*-algebra generated by the semigroup {C_{phi_s} : 0 < s < 1} of composition operators acting on the Hardy space of the unit disk. We determine the joint approximate point spectrum of a related collection of operators and show that the quotient of the C*-algebra by its commutator ideal is isomor

Michael Wilkinson, Bernhard Mehlig, Kristian Gustavsson

We obtain an implicit equation for the correlation dimension of dynamical systems in terms of an integral over a propagator. We illustrate the utility of this approach by evaluating the correlation dimension for inertial particles suspended in a random flow. In the limit where the correlation time of the flow field approaches zero, taking the short-time limi

Rutger van Haasteren, Yuri Levin

Pulsar timing arrays (PTAs) are designed to detect gravitational waves with periods from several months to several years, e.g. those produced by by wide supermassive black-hole binaries in the centers of distant galaxies. Here we show that PTAs are also sensitive to mergers of supermassive black holes. While these mergers occur on a timescale too short to be

Semion K. Saikin, Roberto Olivares-Amaya, Dmitrij Rappoport, Michael Stopa

We study the effects of chemical bonding on Raman scattering from benzenethiol chemisorbed on silver clusters using time-dependent density functional theory (TDDFT). Raman scattering cross sections are computed using a formalism that employs analytical derivatives of frequency-dependent electronic polarizabilities, which treats both off-resonant and resonant

P. Sikivie

The hypothesis of an `invisible&#39; axion was made by Misha Shifman and others, approximately thirty years ago. It has turned out to be an unusually fruitful idea, crossing boundaries between particle physics, astrophysics and cosmology. An axion with mass of order $10^{-5}$ eV (with large uncertainties) is one of the leading candidates for the dark matter

Martin Asplund, Nicolas Grevesse, A. Jacques Sauval, Pat Scott

The solar chemical composition is an important ingredient in our understanding of the formation, structure and evolution of both the Sun and our solar system. Furthermore, it is an essential reference standard against which the elemental contents of other astronomical objects are compared. In this review we evaluate the current understanding of the solar pho

Jesper Sommer-Larsen, Sune Toft

In order to investigate the structure and dynamics of the recently discovered massive (M_* > 10^11 M_sun) compact z~2 galaxies, cosmological hydrodynamical/N-body simulations of a proto-cluster region have been undertaken. At z=2, the highest resolution simulation contains ~5800 resolved galaxies, of which 509, 27 and 5 have M_* > 10^10 M_sun, > 10^11 M_sun

Michel X. Goemans, Nicholas J. A. Harvey, Kamal Jain, Mohit Singh

We present an algorithm for the asymmetric traveling salesman problem on instances which satisfy the triangle inequality. Like several existing algorithms, it achieves approximation ratio O(log n). Unlike previous algorithms, it uses randomized rounding.

David Glickenstein, Tracy L. Payne

We give a global picture of the Ricci flow on the space of three-dimensional, unimodular, nonabelian metric Lie algebras considered up to isometry and scaling. The Ricci flow is viewed as a two-dimensional dynamical system for the evolution of structure constants of the metric Lie algebra with respect to an evolving orthonormal frame. This system is amenable

Anna Ciechan, Karol I. Wysokinski

The calculations of the local and global properties of two band superconductors have been presented with particular attention to the role of the inter-orbital scattering of pairs. The properties of such superconductors are very different from a single band or typical two band systems with dominant intra-band pairing interactions. The role of Van Hove singula

Timothy H. Boyer

It is pointed out that relativistic classical electron theory with classical electromagnetic zero-point radiation has a scaling symmetry which is suitable for understanding the equilibrium behavior of classical thermal radiation at a spectrum other than the Rayleigh-Jeans spectrum. In relativistic classical electron theory, the masses of the particles are th

Matias Nordin, Martin Nilsson-Jacobi, Magnus Nydén

This paper presents a mixed basis approach for Laplace eigenvalue problems, which treats the boundary as a perturbation of the free Laplace operator. The method separates the boundary from the volume via a generic function that can be pre-calculated and thereby effectively reduces the complexity of the problem to a calculation over the surface. Several eigen

Xin Gao, Daniel Q. Pu, Yuehua Wu, Hong Xu

In a Gaussian graphical model, the conditional independence between two variables are characterized by the corresponding zero entries in the inverse covariance matrix. Maximum likelihood method using the smoothly clipped absolute deviation (SCAD) penalty (Fan and Li, 2001) and the adaptive LASSO penalty (Zou, 2006) have been proposed in literature. In this a

R. W. Porcas

Aims: The effect of frequency-dependent AGN core positions (``core-shifts&#39;&#39;) on radio Very Long Baseline Interferometry (VLBI) global astrometry measurements is investigated. Methods: The basic equations relating to VLBI astrometry are reviewed, including the effects of source structure. A power-law representation of core-shifts, based on both observ

C. Rodríguez-López, A. E. Lynas-Gray, D. Kilkenny, J. MacDonald

A spectroscopic analysis of SDSS J160043.6+074802.9, a binary system containing a pulsating subdwarf-O (sdO) star with a late-type companion, yields Teff = 70 000 +/- 5000 K and log g = 5.25 +/- 0.30, together with a most likely type of K3V for the secondary star. We compare our results with atmospheric parameters derived by Fontaine et al. (2008) and in the

Leandro G. Gomes

We study the behaviour of differential forms in a manifold having at least one of their maximal isotropic local distributions endowed with the special algebraic property of being decomposable. We show that they can be represented as the sum of a form with constant coefficients and one that vanishes whenever contracted with vector fields in the former distrib

Xuejun Gu, Hubert Pan, Yun Liang, Richard Castillo

Online adaptive radiation therapy (ART) promises the ability to deliver an optimal treatment in response to daily patient anatomic variation. A major technical barrier for the clinical implementation of online ART is the requirement of rapid image segmentation. Deformable image registration (DIR) has been used as an automated segmentation method to transfer

Yuen Au Yeung, Gero Friesecke, Bernd Schmidt

We investigate ground state configurations of atomic systems in two dimensions interacting via short range pair potentials. As the number of particles tends to infinity, we show that low-energy configurations converge to a macroscopic cluster of finite surface area and constant density, the latter being given by the density of atoms per unit volume in the tr

Ryan N. Gutenkunst, Ryan D. Hernandez, Scott H. Williamson, Carlos D. Bustamante

Demographic models built from genetic data play important roles in illuminating prehistorical events and serving as null models in genome scans for selection. We introduce an inference method based on the joint frequency spectrum of genetic variants within and between populations. For candidate models we numerically compute the expected spectrum using a diff

Luca Bonanno

The Chiral Dilaton Model is a chiral lagrangian in which the breaking of scale invariance is regulated by the expectation value of a scalar field, called dilaton. Here we provide a Fortran code \cite{epaps,ind}, as a tool to make calculations within the Chiral Dilaton Model at finite density and temperature. The calculations are improved respect to previous

E. T. D. Matsushita, E. J. V. de Passos

The properties of the superfluid phase of ultra cold bosonic atoms loaded in a circular array are investigated in the framework of the Bose-Hubbard model and the Bogoliubov theory. We derive and solve the Gross-Pitaevskii equation of the model to find that the atoms condense in states of well-defined quasimomentum. A detailed analysis of the coupling structu

Sean Stotyn, Robert Mann

We employ a thermodynamic analysis to determine the phase structure of Eguchi-Hanson solitons, Schwarzschild-AdS/$\mathbb{Z}_k$ black holes and thermal AdS/$\mathbb{Z}_k$. The Euclidean actions are calculated by two equable means: the first uses the Eguchi-Hanson soliton as the thermal background while the second makes use of minimal boundary counterterms in

W. Sobków, S. Ciechanowicz, M. Misiaszek

Elastic scattering of transversely polarized electron antineutrino beam off unpolarized electrons can be used to detect the CP-violating effects by measuring the azimuthal asymmetry of recoil electrons caused by the interference terms between the standard vector $c_{V}^{L}$, axial $c_{A}^{L}$ couplings of left-chirality antineutrinos and exotic scalar $c_{S}

Michael Galperin, Abraham Nitzan, Mark A. Ratner

We discuss the usefulness of Born-Oppenheimer potential surfaces for nuclear dynamics for molecules strongly coupled to metal surfaces. A simple model demonstrating the construction of such surface for a molecular junction is discussed.

Fraser Watson, Lyndsay Fletcher, Silvia Dalla, Stephen Marshall

The distributions of sunspot longitude at first appearance and at disappearance display an east-west asymmetry that results from a reduction in visibility as one moves from disk centre to the limb. To first order, this is explicable in terms of simple geometrical foreshortening. However, the centre-to-limb visibility variation is much larger than that predic

Antonio F. Ranada, Alfredo Tiemblo

We analyze here the reasons why an explanation of the Pioneer anomaly proposed by the authors is fully compatible with the cartography of the solar system. First, this proposal posits that the phenomenon is an apparent acceleration, not a real one, caused by a progressive desynchronization of the astronomical and the atomic clock-times, after they had been s

G. Giovannini, A. Bonafede, L. Feretti, F. Govoni

The Intra-Cluster Medium is characterized by thermal emission, and by the presence of large scale magnetic fields. In some clusters of galaxies a diffuse non-thermal emission is also present, located at the cluster center and named radio halo. These sources indicate the existence of relativistic particles and magnetic fields in the cluster volume. In this pa

Y. Charles Li

This is a survey on the recent theory of chaos in partial differential equations.

H. Bercovici, W. S. Li, D. Timotin

We produce a family of reductions for Schubert intersection problems whose applicability is checked by calculating a linear combination of the dimensions involved. These reductions do not alter the Littlewood-Richardson coefficient, and they lead to an explicit solution of the intersection problem when this coefficient is 1.

P. Samuelsson, I. Neder, M. Buttiker

In this work we discuss a theory for entanglement generation, characterization and detection in fermionic two-particle interferometers at finite temperature. The motivation for our work is provided by the recent experiment by the Heiblum group, Neder et al, Nature 448, 333 (2007), realizing the two particle interferometer proposed by Samuelsson, Sukhorukov,

P. A. Woudt, B. Warner, D. O&#39;Donoghue, D. A. H. Buckley

We analyse four light curves obtained at high time resolution (~ 0.1 s) with the 11-m Southern African Large Telescope, at the ends of two normal outbursts and one superoutburst of the dwarf nova VW Hyi. All of these contain at least some Dwarf Nova Oscillations (DNOs), which, when at their highest amplitudes, are seen in unprecedented detail. In addition to

Eugen Staab, Martin Caminada

We study the notion of informedness in a client-consultant setting. Using a software simulator, we examine the extent to which it pays off for consultants to provide their clients with advice that is well-informed, or with advice that is merely meant to appear to be well-informed. The latter strategy is beneficial in that it costs less resources to keep up-t

Marcella Marconi

RR Lyrae stars play an important role as distance indicators and stellar population tracers. In this context the construction of accurate pulsation models is crucial to understand the observed properties and to constrain the intrinsic stellar parameters of these pulsators. The physical mechanism driving pulsation in RR Lyrae stars has been known since the mi

T. Yaqoob, K. D. Murphy, L. Miller, T. J. Turner

The absolute luminosity of the Fe Kalpha emission line from matter illuminated by X-rays in astrophysical sources is nontrivial to calculate except when the line-emitting medium is optically-thin to absorption and scattering. We characterize the Fe Kalpha line flux using a dimensionless efficiency, defined as the fraction of continuum photons above the Fe K

Adam Osȩkowski

Let $M,N$ be real-valued martingales such that $N$ is differentially subordinate to $M$. The paper contains the proofs of the following weak-type inequalities: (i) If $M\geq0$ and $0<p\leq1$, then \[\Vert N\Vert_{p,\infty}\leq2\Vert M\Vert_p\] and the constant is the best possible. (ii) If $M\geq0$ and $p\geq2$, then \[\Vert N\Vert_{p,\infty}\leq\frac{p}{2}(

Daniel J. Majaess, David G. Turner, David J. Lane

A campaign is described, open to participation by interested AAVSO members, of follow-up observations for newly-discovered Cepheid variables in undersampled and obscured regions of the Galaxy. A primary objective being to use these supergiants to clarify the Galaxy&#39;s spiral nature. Preliminary multiband photometric observations are presented for three Ce

Frédéric Lannuzel, Valérie Burklé-Vitzthum, Roda Bounaceur, Paul-Marie Marquaire

Among the numerous questions that arise concerning the exploitation of petroleum from unconventional reservoirs, lie the questions of the composition of hydrocarbons present in deep seated HP-HT reservoirs or produced during in-situ upgrading steps of heavy oils and oil shales. Our research shows that experimental hydrocarbon cracking results obtained in the

S. Capozziello, M. De Laurentis, L. Forte, F. Garufi

Gravitational waveforms and production could be considerably affected by gravitomagnetic corrections considered in relativistic theory of orbits. Beside the standard periastron effect of General Relativity, new nutation effects come out when c^{-3} corrections are taken into account. Such corrections emerge as soon as matter-current densities and vector grav

Yu-Juan Jien, Jin Ma

In this paper, we study the existence and uniqueness of a class of stochastic differential equations driven by fractional Brownian motions with arbitrary Hurst parameter $H\in (0,1)$. In particular, the stochastic integrals appearing in the equations are defined in the Skorokhod sense on fractional Wiener spaces, and the coefficients are allowed to be random

E. Minguzzi

Every time function on spacetime gives a (continuous) total preordering of the spacetime events which respects the notion of causal precedence. The problem of the existence of a (semi-)time function on spacetime and the problem of recovering the causal structure starting from the set of time functions are studied. It is pointed out that these problems have a

Eva Maria Galan Moya, Armelle Le Guelte, Julie Gavard

Angiogenesis recapitulates the growth of blood vessels that progressively expand and remodel into a highly organized and stereotyped vascular network. During adulthood, endothelial cells that formed the vascular wall retain their plasticity and can be engaged in neo-vascularization in response to physiological stimuli, such as hypoxia, wound healing and tiss

Jorick S. Vink, B. Davies, T. J. Harries, R. D. Oudmaijer

(abridged) As the favoured progenitors of long-duration gamma-ray bursts, massive stars may represent our best signposts of individual objects in the early Universe, but special conditions seem required to make these bursters, which might originate from the progenitor&#39;s rapid rotation and associated asymmetry. To obtain empirical constraints on the inter

R. Meppelink, S. B. Koller, J. M. Vogels, H. T. C. Stoof

We study the second sound dipole mode in a partially Bose-Einstein condensed gas. This mode is excited by spatially separating and releasing the center-of-mass of the Bose-Einstein condensate (BEC) with respect to the thermal cloud, after which the equilibration is observed. The oscillation frequency and the damping rate of this mode is studied for different

Kerem Ege, Xavier Boutillon, Bertrand David

Usual modal analysis techniques are based on the Fourier transform. Due to the Delta T . Delta f limitation, they perform poorly when the modal overlap mu exceeds 30%. A technique based on a high-resolution analysis algorithm and an order-detection method is presented here, with the aim of filling the gap between the low- and the high-frequency domains (30%<

David Richeson, Jim Wiseman

We introduce index systems, a tool for studying isolated invariant sets of dynamical systems that are not necessarily hyperbolic. The mapping of the index systems mimics the expansion and contraction of hyperbolic maps on the tangent space, and they may be used like Markov partitions to generate symbolic dynamics. Every continuous dynamical system satisfying

Pengzi Miao, Luen-Fai Tam, Naqing Xie

Given a spacelike 2-surface $Σ$ in a spacetime $N$ and a constant future timelike unit vector $T_0 $ in $\R^{3,1}$, we derive upper and lower estimates of Wang-Yau quasilocal energy $E(Σ, X, T_0)$ for a given isometric embedding $X$ of $Σ$ into a flat 3-slice in $\R^{3,1}$. The quantity $ E(Σ, X, T_0) $ itself depends on the choice of $X$, however the infimu

R. Capuzzo-Dolcetta

In this paper I will outline some of the aspects and problems of modern celestial mechanics and stellar dynamics, in the context of the quickly growing computing facilities. I will point the attention on the great advantages in using, for astrophysical simulations, the modern, fast and cheap Graphic Processing Units (GPUs) acting as true supercomputers. Fina

Olivier Krebs, Emile Benjamin, Aristide Lemaître

We report on the micro-photoluminescence spectroscopy of InAs/GaAs quantum dots (QD) doped by a single Mn atom in a magnetic field either longitudinal or perpendicular to the optical axis. In both cases the spectral features of positive trion (X+) are found to split into strongly circularly polarized components, an effect very surprising in a perpendicular m

Philip T. Gressman

This paper reconsiders the uniform sublevel set estimates of Carbery, Christ, and Wright (1999) and Phong, Stein, and Sturm (2001) from a geometric perspective. This perspective leads one to consider a natural collection of homogeneous, nonlinear differential operators which generalize mixed derivatives in $\R^d$. As a consequence, it is shown that, in the c

Jerome Ferrari

The evaluation of fluid forces on the stem is important for wear prediction of valve and actuator guidance parts. While estimating the axial load is straight forward, estimating and/or measuring the side load is more difficult, especially for globe valves. Therefore, measurements are carried out on an ad hoc, scale 1, model of a 2&#34; globe valve. The body

Francisco M. Fernández, Julián Echave

We review some of the few available nonadiabatic calculations of dipole moments. We show that those carried out in a laboratory-fixed set of coordinate axes are bound to fail and discuss the more reasonable ones in a molecule-fixed reference frame. For completeness we also describe the standard Born--Oppenheimer calculations of dipole moments. We briefly add

C. J. Short, P. A. Thomas

We present hydrodynamical N-body simulations of clusters of galaxies with feedback taken from semi-analytic models of galaxy formation. The advantage of this technique is that the source of feedback in our simulations is a population of galaxies that closely resembles that found in the real universe. We demonstrate that, to achieve the high entropy levels fo