April 2009 arXiv papers — page 43

Vladimir Shchigolev

Let G be a universal Chevalley group over an algebraically closed field and U^- be the subalgebra of Dist(G) generated by all divided powers X_{α,m} with α<0. We conjecture an algorithm to determine if Fe^+_ω\ne0, where F\in\U^-, ωis a dominant weight and e^+_ωis a highest weight vector of the Weyl module Δ(ω). This algorithm does not use bases of Δ(ω) and i

S. Thirukkanesh, S. D. Maharaj

A new class of exact solutions of the Einstein-Maxwell system is found in closed form. This is achieved by choosing a generalised form for one of the gravitational potentials and a particular form for the electric field intensity. For specific values of the parameters it is possible to write the new series solutions in terms of elementary functions. We regai

Marco Congedo, Dinh-Tuan Pham

The approximate joint diagonalization (AJD) is an important analytic tool at the base of numerous independent component analysis (ICA) and other blind source separation (BSS) methods, thus finding more and more applications in medical imaging analysis. In this work we present a new AJD algorithm named SDIAG (Spheric Diagonalization). It imposes no constraint

Vivien Robinet, Gilles Bisson, Mirta B. Gordon, Benoît Lemaire

This paper applies machine learning techniques to student modeling. It presents a method for discovering high-level student behaviors from a very large set of low-level traces corresponding to problem-solving actions in a learning environment. Basic actions are encoded into sets of domain-dependent attribute-value patterns called cases. Then a domain-indepen

A. Beesham, S. V. Chervon, S. D. Maharaj

We suggest the use of a nonlinear sigma model as the source which supports an emergent universe. The two-component nonlinear sigma model is considered as the simplest model containing inflaton and auxiliary chiral fields.

Ioannis Koukoutsidis, Petros Papaioannou, Michael E. Theologou

The use of advanced sequential paging algorithms has been suggested as a means to reduce the signaling cost in future mobile cellular networks. In a proposed algorithm (Koukoutsidis and Theologou, 2003), the system can use the additional information of the last interaction cell combined with a mobility model to predict the short-term location probabilities a

Ming Xiong, Huinan Zheng, Yuming Wang, Shui Wang

Numerical studies have been performed to interpret the observed &#34;shock overtaking magnetic cloud (MC)&#34; event by a 2.5 dimensional magnetohydrodynamic (MHD) model in heliospheric meridional plane. Results of an individual MC simulation show that the MC travels with a constant bulk flow speed. The MC is injected with very strong inherent magnetic field

A. D. Christianson, M. D. Lumsden, S. E. Nagler, G. J. MacDougall

We report neutron scattering measurements on single crystals of BaFe$_{1.92}$Co$_{0.08}$As$_2$. The magnetic Bragg peak intensity is reduced by 6 % upon cooling through T$_C$. The spin dynamics exhibit a gap of 8 meV with anisotropic three-dimensional (3d) interactions. Below T$_C$ additional intensity appears at an energy of $\sim$4.5(0.5) meV similar to pr

Ming Xiong, Huinan Zheng, Yuming Wang, Shui Wang

Numerical studies of the interplanetary &#34;shock overtaking magnetic cloud (MC)&#34; event are continued by a 2.5 dimensional magnetohydrodynamic (MHD) model in heliospheric meridional plane. Interplanetary direct collision (DC)/oblique collision (OC) between an MC and a shock results from their same/different initial propagation orientations. For radially

Hans-Ulrich Stark, Claudio J. Tessone, Frank Schweitzer

We investigate an extension of the voter model in which voters are equipped with an individual inertia to change their opinion. This inertia depends on the persistence time of a voter&#39;s current opinion (ageing). We focus on the case of only two different inertia values: zero if a voter just changed towards a new opinion and $ν$ otherwise. We are interest

Patrick Groeber, Frank Schweitzer, Kerstin Press

A local culture denotes a commonly shared behaviour within a cluster of firms. Similar to social norms or conventions, it is an emergent feature resulting from the firms&#39; interaction in an economic network. To model these dynamics, we consider a distributed agent population, representing e.g. firms or individuals. Further, we build on a continuous opinio

P. M. Mednis

The problem concerning the form of the electrostatic field potential of the infinite charged metallic plane contacting with the metallic sphere is solved. The distributions of the surface charge densities both on the plane and the sphere and also the force acting on the sphere that causing to tear away from the plane are found. The expressions found for the

S. T. Petcov, H. Sugiyama, Y. Takanishi

The connection between the neutrinoless double beta ((ββ)_{0 ν}-) decay effective Majorana mass, |M_{ee}|, and the branching ratios of the decays H^{\pm\pm}\to l^\pm {l&#39;}^\pm, l,{l&#39;}= e,μ, of the doubly charged Higgs boson H^{\pm\pm} is analysed within the Higgs Triplet Model of neutrino mass generation. We work in the version of the model with expli

Fabio Biancalana, Leonidas Mouchliadis, Celestino Creatore, Simon Osborne

Periodic structures resonantly coupled to excitonic media allow the existence of extra intragap modes (&#39;Braggoritons&#39;), due to the coupling between Bragg photon modes and 3D bulk excitons. This induces unique and unexplored dispersive features, which can be tailored by properly designing the photonic bandgap around the exciton resonance. We report th

Iasson Karafyllis, Zhong-Ping Jiang

A new Small-Gain Theorem is presented for general nonlinear control systems. The novelty of this research work is that vector Lyapunov functions and functionals are utilized to derive various input-to-output stability and input-to-state stability results. It is shown that the proposed approach recovers several recent results as special instances and is exten

O. P. Solovtsova, Yu. D. Chernichenko

The new relativistic Coulomb-like threshold resummation $S$-factor in quantum chromodynamics is obtained. The consideration is given within the framework of quasipotential approach in quantum field theory which is formulated in relativistic configuration representation for two particles of unequal masses.

Alexander Klitz

We show that the correlation functions and the free energy of the formal Hermitean 1-matrix model can be described by the recently proposed Lagrangean formalism to all orders. In addition, the loop equation of this formalism is stated and solved up to the fifth order in 1 / N^2 explicitly.

Harish Seshadri

Let $(M^n,g)$, $n \ge 4$, be a compact simply-connected Riemannian manifold with nonnegative isotropic curvature. Given $0<l\le L$, we prove that there exists $\eps = \eps (l,L,n)$ satisfying the following: If the scalar curvature $s$ of $g$ satisfies $$ l \le s \le L $$ and the Einstein tensor satisfies $$ | Ric - \frac {s}{n}g | \le \eps$$ then $M$ is diff

XIONG Ming, PENG Zhong, HU Youqiu, ZHENG Huinan

Three-dimensional global magnetohydrodynamic simulations of the solar wind - magnetosphere - ionosphere system are carried out to explore the dependence of the magnetospheric reconnection voltage, the ionospheric transpolar potential, and the field aligned currents (FACs) on the solar wind driver and ionosphere load for the cases with pure southward interpla

Ming Xiong, Huinan Zheng, S. T. Wu, Yuming Wang

Numerical studies of the interplanetary &#34;multiple magnetic clouds (Multi-MC)&#34; are performed by a 2.5-dimensional ideal magnetohydrodynamic (MHD) model in the heliospheric meridional plane. Both slow MC1 and fast MC2 are initially emerged along the heliospheric equator, one after another with different time interval. The coupling of two MCs could be c

Jaime A. Anguita, Michael Chertkov, Mark A. Neifeld, Bane Vasic

We address the problem of the joint sequence detection in partial-response (PR) channels and decoding of low-density parity-check (LDPC) codes. We model the PR channel and the LDPC code as a combined inference problem. We present for the first time the derivation of the belief propagation (BP) equations that allow the simultaneous detection and decoding of a

Jiandong Wang, Jianke Yang, Tristram J. Alexander, Yuri S. Kivshar

We study self-trapped localized nonlinear states in the form of truncated Bloch waves in one-dimensional optical lattices, which appear in the gaps of the linear bandgap spectrum. We demonstrate the existence of families of such localized states which differ by the number of intensity peaks. These families do not bifurcate from the band edge, and their power

Shannon Starr

The Mallows model on $S_n$ is a probability distribution on permutations, $q^{d(π,e)}/P_n(q)$, where $d(π,e)$ is the distance between $π$ and the identity element, relative to the Coxeter generators. Equivalently, it is the number of inversions: pairs $(i,j)$ where $1\leq i<j\leq n$, but $π_i>π_j$. Analyzing the normalization $P_n(q)$, Diaconis and Ram calcu

Frédérick Tremblay, Alexander V. Turbiner, Pavel Winternitz

An infinite family of exactly-solvable and integrable potentials on a plane is introduced. It is shown that all already known rational potentials with the above properties allowing separation of variables in polar coordinates are particular cases of this family. The underlying algebraic structure of the new potentials is revealed as well as its hidden algebr

Eric A. Carlen, Elliott H. Lieb

A theorem of Mirsky provides necessary and sufficient conditions for the existence of an N-square complex matrix with prescribed diagonal entries and prescribed eigenvalues. We give a simple inductive proof of this theorem.

W. Guo, J. D. Wright, S. B. Cahn, J. A. Nikkel

Metastable helium molecules generated in a discharge near a sharp tungsten tip operated in either pulsed mode or continuous field-emission mode in superfluid liquid $^{4}$He are imaged using a laser-induced-fluorescence technique. By pulsing the tip, a small cloud of He$_{2}^{*}$ molecules is produced. At 2.0 K, the molecules in the liquid follow the motion

M. E. Araujo, W. R. Stoeger

A rigorous demonstration that given appropriate data on our past light cone leads to the determination of the metric functions and all their time derivatives on our past light cone is presented, thus showing how to evolve the solution we obtain from data on the light cone off it in a well-defined and straightforward way. It also automatically gives a procedu

Hans L. Bodlaender, Fedor V. Fomin, Daniel Lokshtanov, Eelko Penninkx

In a parameterized problem, every instance I comes with a positive integer k. The problem is said to admit a polynomial kernel if, in polynomial time, one can reduce the size of the instance I to a polynomial in k, while preserving the answer. In this work we give two meta-theorems on kernelzation. The first theorem says that all problems expressible in Coun

Cong-Feng Qiao, De-Long Ren, Peng Sun

In this work, we calculate the $h_c(^1P_1)$ production rate at the LHC to leading order of the strong coupling constant, for both color-singlet and -octet mechanisms. Numerical results show that a considerable number of $h_c$ events with moderate transverse momentum $p_T$ will be produced in the early run of the LHC, which will supply a good opportunity to f

Jason Fox Manning

Motivated by a question of Gordon and Wilton, we consider the question of which collections of words are &#34;virtually geometric&#34;. In particular, we prove that some words (e.g. bbaaccabc) are not virtually geometric.

Leonid M. Malyshkin

A theoretical model of quasi-stationary, two-dimensional magnetic reconnection is presented in the framework of incompressible two-fluid magnetohydrodynamics (MHD). The results are compared with recent numerical simulations and experiment.

Bian Qian, Melissa Loureiro, David Gagnon, Anubhav Tripathi

Droplet deposition onto a hydrophobic surface is studied experimentally and numerically. A wide range of droplet sizes can result from the same syringe, depending strongly on the needle retraction speed. Three regimes are identified according to the motion of the contact line. In Region I, at slow retraction speeds, the contact line expands and large droplet

Linh Anh Nguyen, Andrzej Szałas

We reformulate Pratt&#39;s tableau decision procedure of checking satisfiability of a set of formulas in PDL. Our formulation is simpler and more direct for implementation. Extending the method we give the first EXPTIME (optimal) tableau decision procedure not based on transformation for checking consistency of an ABox w.r.t. a TBox in PDL (here, PDL is trea

Ernie Croot, Derrick Hart

In the present paper we show that if A is a set of n real numbers, and the product set A.A has at most n^(1+c) elements, then the k-fold sumset kA has at least n^(log(k/2)/2 log 2 + 1/2 - f_k(c)) elements, where f_k(c) -> 0 as c -> 0. We believe that the methods in this paper might lead to a much stronger result; indeed, using a result of Trevor Wooley on Vi

A. Mangalam, Gopal-Krishna, Paul J. Wiita

The recently discovered apparent dramatic expansion in the effective radii of massive elliptical galaxies from $z \simeq 2$ to $z \simeq 0.1$ has been interpreted in terms of either galaxy mergers or the rapid loss of cold gas due to AGN feedback. In examining the latter case we have quantified the extent of the expansion, which is uncertain observationally,

A. di Prisco, L. Herrera, M. A. H. MacCallum, N. O. Santos

We consider diagonal cylindrically symmetric metrics, with an interior representing a general non-rotating fluid with anisotropic pressures. An exterior vacuum Einstein-Rosen spacetime is matched to this using Darmois matching conditions. We show that the matching conditions can be explicitly solved for the boundary values of metric components and their deri

Fumio Hiai, Milan Mosonyi, Masahito Hayashi

The asymptotic discrimination problem of two quantum states is studied in the setting where measurements are required to be invariant under some symmetry group of the system. We consider various asymptotic error exponents in connection with the problems of the Chernoff bound, the Hoeffding bound and Stein&#39;s lemma, and derive bounds on these quantities in

Jorge Quintanilla, Orion Ciftja

We present a theory of spontaneous Fermi surface deformations for half-filled Landau levels (filling factors of the form $ν=2n+1/2$). We assume the half-filled level to be in a compressible, Fermi liquid state with a circular Fermi surface. The Landau level projection is incorporated via a modified effective electron-electron interaction and the resulting ba

Amine Ahriche

In this work, we study the electroweak sphalerons in a 5D background, where the fifth dimension lies on an interval. We consider two specific cases: flat space-time and the anti-de Sitter space-time compactified on S^{1}/Z_{2}. In our work, we take the SU(2) gauge-Higgs model, where the gauge fields reside in the 5D bulk; but the Higgs doublet is confined in

M. Rémon

The relationship between the complexity classes P and NP is an unsolved question in the field of theoretical computer science. In this paper, we look at the link between the P - NP question and the &#34;Deterministic&#34; versus &#34;Non Deterministic&#34; nature of a problem, and more specifically at the temporal nature of the complexity within the NP class

Yu-Chang Chen, Yu-Shen Liu

The miniaturization of thermoelectric nanojunctions raises a fundamental question: do the thermoelectric quantities of the bridging materials in nanojunctions remain to display material properties or show junction properties? In order to answer this question, we investigate the Seebeck coefficient $S$ and the thermoelectric figure of merit $ZT$ especially in

M. A. Jivulescu, E. Ferraro, A. Napoli, A. Messina

The dynamical behavior of a star network of spins, wherein each of N decoupled spins interact with a central spin through non uniform Heisenberg XX interaction is exactly studied. The time-dependent Schrodinger equation of the spin system model is solved starting from an arbitrary initial state. The resulting solution is analyzed and briefly discussed.

Yi Zhang, Ying Ran, Ashvin Vishwanath

We study three dimensional systems where strong repulsion leads to an insulating state via spontaneously generated spin-orbit interactions. We discuss a microscopic model where the resulting state is topological. Such topological `Mott&#39; insulators differ from their band insulator counterparts in that they possess an additional order parameter, a rotation

Noam Soker, Saeqa Dil Vrtilek

We suggest that the radio emission from the dwarf nova SS Cyg during outburst comes from magnetic activity that formed a corona (similar to coronae found in magnetically active stars), rather than from jets. We base our claim on the recent results of Laor & Behar, who found that when the ratio between radio and X-ray flux of accretion disks in radio-quiet qu

Michaela Goetz, Ashwin Machanavajjhala, Guozhang Wang, Xiaokui Xiao

Search engine companies collect the &#34;database of intentions&#34;, the histories of their users&#39; search queries. These search logs are a gold mine for researchers. Search engine companies, however, are wary of publishing search logs in order not to disclose sensitive information. In this paper we analyze algorithms for publishing frequent keywords, qu

Thorkild Hansen, Gerald Kaiser

Huygens&#39; principle has a well-known problem with back-propagation due to the spherical nature of the secondary wavelets. We solve this by analytically continuing the surface of integration. If the surface is a sphere of radius $R$, this is done by complexifying $R$ to $R+ia$. The resulting complex sphere is shown to be a real bundle of disks with radius

L. Chkhaidze, P. Danielewicz, T. Djobava, L. Kharkhelauri

Features of anisotropic collective flow and spectral temperatures have been determined for lambda hyperons emitted from C + C collisions, at incident momentum of 4.2 AGeV/c, measured using the Propane Bubble Chamber of JINR at Dubna. Moreover, characteristics of protons and of negative pions, emitted from those collisions, have been determined and provided f

Steven V Sam, Kevin M. Woods

A rational polytope is the convex hull of a finite set of points in $\R^d$ with rational coordinates. Given a rational polytope $P \subseteq \R^d$, Ehrhart proved that, for $t\in\Z_{\ge 0}$, the function $#(tP \cap \Z^d)$ agrees with a quasi-polynomial $L_P(t)$, called the Ehrhart quasi-polynomial. The Ehrhart quasi-polynomial can be regarded as a discrete v

Guodong Liu, Haiyun Liu, Lin Zhao, Wentao Zhang

High resolution angle-resolved photoemission measurements have been carried out on BaFe2As2, a parent compound of the FeAs-based superconductors. In the magnetic ordering state, there is no gap opening observed on the Fermi surface. Instead, dramatic band structure reorganization occurs across the magnetic transition. The appearance of the singular Fermi spo

Harm Derksen, Jerzy Weyman, Andrei Zelevinsky

We continue the study of quivers with potentials and their representations initiated in the first paper of the series. Here we develop some applications of this theory to cluster algebras. As shown in the &#34;Cluster algebras IV&#34; paper, the cluster algebra structure is to a large extent controlled by a family of integer vectors called g-vectors, and a f

D0 Collaboration, V. Abazov

We provide the most precise measurement of the WW production cross section in p-pbar collisions to date at a center of mass energy of 1.96 TeV, and set limits on the associated trilinear gauge couplings. The WW->lvl&#39;v (l,l&#39;=e,mu) decay channels are analyzed in 1 fb^(-1) of data collected by the D0 detector at the Fermilab Tevatron Collider. The measu

Joseph M. Hahn, Joseph N. Spitale, Carolyn C. Porco

(Abridged) The following describes a model of a broad planetary ring whose sharp edge is confined by a satellite&#39;s m^th Lindblad resonance (LR). This model uses a streamline formalism to calculate the ring&#39;s internal forces, namely, ring gravity, pressure, viscosity, as well as a hypothetical drag force. The model calculates the streamlines&#39; forc

M. T. Homer Reid, Alejandro W. Rodriguez, Jacob White, Steven G. Johnson

We introduce an efficient technique for computing Casimir energies and forces between objects of arbitrarily complex 3D geometries. In contrast to other recently developed methods, our technique easily handles non-spheroidal, non-axisymmetric objects and objects with sharp corners. Using our new technique, we obtain the first predictions of Casimir interacti

A. Prsa, E. F. Guinan, E. J. Devinney, S. G. Engle

Observational astronomy has changed drastically in the last decade: manually driven target-by-target instruments have been replaced by fully automated robotic telescopes. Data acquisition methods have advanced to the point that terabytes of data are flowing in and being stored on a daily basis. At the same time, the vast majority of analysis tools in stellar

I. V. Lebedeva, A. A. Knizhnik, A. M. Popov, Yu. E. Lozovik

Tribological characteristics of nanotube-based nanoelectromechanical systems (NEMS) exemplified by a gigahertz oscillator are studied. Various factors that influence the tribological properties of the nanotube-based NEMS are quantitatively analyzed with the use of molecular dynamics calculations of the quality factor (Q-factor) of the gigahertz oscillator. W

Orlando Alvarez

These lectures describe how to study the geometry of some black holes without the use of coordinates.

Mark A. Peletier, Marco Veneroni

We study a new formulation for the eikonal equation |grad u| =1 on a bounded subset of R^2. Considering a field P of orthogonal projections onto 1-dimensional subspaces, with divergence bounded in L^2, we prove existence and uniqueness for solutions of the equation P div P=0. We give a geometric description, comparable with the classical case, and we prove t

Ivan O. Kitov

Economics does not need a scientific revolution. Economics needs accurate measurements according to high standards of natural sciences and meticulous work on revealing empirical relationships between measured variables.

David A. Turton, Klaas Wynne

Structural relaxation in the peptide model N-methylacetamide (NMA) is studied experimentally by ultrafast optical Kerr-effect spectroscopy over the normal-liquid temperature range and compared to the relaxation measured in water at room temperature. It is seen that in both hydrogen-bonding liquids, beta relaxation is present and in each case it is found that

J. Bluemer, R. Engel, J. R. Hoerandel

This review summarizes recent developments in the understanding of high-energy cosmic rays. It focuses on galactic and presumably extragalactic particles in the energy range from the knee (10^15 eV) up to the highest energies observed (>10^20 eV). Emphasis is put on observational results, their interpretation, and the global picture of cosmic rays that has e

Kenneth H. Karlsen, Trygve K. Karper

We propose and analyze a finite element method for a semi-stationary Stokes system modeling compressible fluid flow subject to a Navier-slip boundary condition. The velocity (momentum) equation is approximated by a mixed finite element method using the lowest order Nedelec spaces of the first kind. The continuity equation is approximated by a standard piecew

D. Segur, A. L. Shuvalov, Y. Pan, B. Audoin

Semi-analytical model for calculating acoustic response to a line-focused laser pulse in an optically absorptive isotropic cylinder is proposed and implemented. It is assumed that the laser input is absorbed over the volume and thus creates a radially distributed thermoelastic source. Closed-form solution is obtained in the Fourier domain. Two inverse Fourie

Sergey Andreyev

The inner views of all our applications are predetermined by the designers; only some non-significant variations are allowed with the help of adaptive interface. In several programs you can find some moveable objects, but it is an extremely rare thing. However, the design of applications on the basis of moveable and resizable objects opens an absolutely new

David A. Turton, Johannes Hunger, Glenn Hefter, Richard Buchner

When salts are added to water, the viscosity generally increases suggesting the ions increase the strength of the water&#39;s hydrogen-bond network. However, infrared pump-probe measurements on electrolyte solutions have found that ions have no influence on the rotational dynamics of water molecules implying no enhance-ment or breakdown of the hydrogen-bond

Ping Wong Ng, Wilhelm Winter

We show that stabilizations of sufficiently noncommutative separable unital C*-algebras with finite nuclear dimension have the corona factorization property.

U. A. Rozikov

In this note we consider several kind of partition functions of one-dimensional models with nearest - neighbor interactions $I_n, n\in \mathbf{Z}$ and spin values $\pm 1$. We derive systems of recursive equations for each kind of such functions. These systems depend on parameters $I_n, n\in \mathbf{Z}$. Under some conditions on the parameters we describe sol

D. R. Heath-Brown

We construct real numbers $α$ for which the pair correlation function \[N^{-1}#\{m<n\le N:||αm^2-αn^2||\le XN^{-1}\}\] tends to $X$ as $N$ grows. Moreover we show for any &#34;Diophantine&#34; $α$ that the pair correlation function is $X+O(X^{7/8})+O((\log N)^{-1}$ for $1\le X\le\log N$.

Arkadiusz K. Kuczaj, Bernard J. Geurts, Darryl D. Holm

Rotation modulates turbulence causing columnar structuring of a turbulent flow in case of sufficiently strong rotation. This yields significant changes in the flow characteristics and dispersion properties, which makes rotational turbulence modulation particularly relevant in the context of atmospheric and oceanic flows. Here we investigate the canonical flo

Markus Hansen, Thomas Strobl

We show that in analogy to the introduction of Poisson structures twisted by a closed 3-form by Park and Klimcik-Strobl, the study of three dimensional sigma models with Wess-Zumino term leads in a likewise way to twisting of Courant algebroid structures by closed 4-forms H. The presentation is kept pedagogical and accessible to physicists as well as to math

Qian Shou, Yanbin Liang, Qun Jiang, Yajian Zheng

We investigate the propagation of the spatial soliton in cylindrical strongly nonlocal media by a novel method of image beam of light. The effect of the boundary on the soliton acting as the dynamic force for the soliton steering is equivalent to the force between the soliton beam and the image beam. The trajectory of the soliton is analytically studied whic

Katepalli R. Sreenivasan, Joerg Schumacher

The Lagrangian view of passive scalar turbulence has recently produced interesting results and interpretations. Innovations in theory, experiments, simulations and data analysis of Lagrangian turbulence are reviewed here in brief. Part of the review is closely related to the so-called Kraichnan model for the advection of the passive scalar in synthetic turbu

P. Amaro, J. P. Santos, F. Parente, A. Surzhykov

A theoretical study the all two-photon transitions from initial bound states with ni = 2, 3 in hydrogenic ions is presented. High-precision values of relativistic decay rates for ions with nuclear charge in the range 1 =< Z =< 92 are obtained through the use of finite basis sets for the Dirac equation constructed from B-splines. We also report the spectral (

Brahim El Asri

This paper studies the problem of the deterministic version of the Verification Theorem for the optimal m-states switching in infinite horizon under Markovian framework with arbitrary switching cost functions. The problem is formulated as an extended impulse control problem and solved by means of probabilistic tools such as the Snell envelop of processes and

Pierre Maréchal, Aude Rondepierre

We propose a general proximal algorithm for the inversion of ill-conditioned matrices. This algorithm is based on a variational characterization of pseudo-inverses. We show that a particular instance of it (with constant regularization parameter) belongs to the class of {\sl fixed point} methods. Convergence of the algorithm is also discussed.

C. Cabanac, R. P. Fender, R. J. H. Dunn, E. G. Koerding

Black hole binary transients undergo dramatic evolution in their X-ray timing and spectral behaviour during outbursts. In recent years a paradigm has arisen in which &#34;soft&#34; X-ray states are associated with an inner disc radius at, or very close to, the innermost stable circular orbit (ISCO) around the black hole, while in &#34;hard&#34; X-ray states

A. Szameit, Y. V. Kartashov, F. Dreisow, M. Heinrich

We report the observation of almost perfect light tunneling inhibition at the edge and inside laser-written waveguide arrays due to band collapse. When the refractive index of the guiding channels is harmonically modulated along the propagation direction and out-of-phase in adjacent guides, light is trapped in the excited waveguide over a long distance due t

T. Rajasekharan, V. Seshubai

We present an Atom-Pair Bond (APB) theory for the energy of a metallic bond based on the ideas of covalent bonding proposed by Pauling. An expression is derived which accurately predicts the signs of the heats of formation of binary alloys. It also explains the characteristics of the Rajasekharan-Girgis lines and their ability to predict accurately concomita

Frank Gibson, Leigh Anderson, Gyorgy Babnigg, Mark Baker

the MIAPE Gel Electrophoresis (MIAPE-GE) guidelines specify the minimum information that should be provided when reporting the use of n-dimensional gel electrophoresis in a proteomics experiment. Developed through a joint effort between the gel-based analysis working group of the Human Proteome Organisation&#39;s Proteomics Standards Initiative (HUPO-PSI; ht

Philippe Eyssidieux, L. Katzarkov, Tony Pantev, Mohan Ramachandran

We prove that the universal covering space of a complex projective manifold is holomorphically convex provided its fundamental group is linear.

Zhaosong Lu, Renato D. C. Monteiro, Ming Yuan

In this paper, we study convex optimization methods for computing the trace norm regularized least squares estimate in multivariate linear regression. The so-called factor estimation and selection (FES) method, recently proposed by Yuan et al. [22], conducts parameter estimation and factor selection simultaneously and have been shown to enjoy nice properties

Masao Iwamatsu

The generic square-gradient density-functional model with triple-parabolic free energy is used to study the stability of a cavity introduced into the stretched liquid. The various properties of the critical cavity, which is the largest stable cavity within the liquid, are compared with those of the critical bubble of the homogeneous bubble nucleation. It is

Zhaosong Lu

In this paper, we consider estimating sparse inverse covariance of a Gaussian graphical model whose conditional independence is assumed to be partially known. Similarly as in [5], we formulate it as an $l_1$-norm penalized maximum likelihood estimation problem. Further, we propose an algorithm framework, and develop two first-order methods, that is, the adap

Zhaosong Lu

In this paper we first study a smooth optimization approach for solving a class of nonsmooth strictly concave maximization problems whose objective functions admit smooth convex minimization reformulations. In particular, we apply Nesterov&#39;s smooth optimization technique [Y.E. Nesterov, Dokl. Akad. Nauk SSSR, 269 (1983), pp. 543--547; Y. E. Nesterov, Mat

Thierry Rabilloud

Because of the outstanding ability of two-dimensional electrophoresis to separate complex mixtures of intact proteins, it would be advantageous to apply it to all types of proteins, including hydrophobic and membrane proteins. Unfortunately, poor solubility hampers the analysis of these molecules. As these problems arise mainly in the extraction and isoelect

Rui-Lin Chu, Jian Li, J. K. Jain, Shun-Qing Shen

The topological insulators have a gap in the bulk but extended states at the edge that can carry current. We study a geometry in which such edge states will manifest themselves through periodic oscillations in the magnetoconductance of a singly connected sample coupled to leads through narrow point contacts. The oscillations occur due to quantum interference

E. J. Chun, S. Scopel, I. Zaballa

We provide a detailed study of gravitational reheating in quintessential inflation generalizing previous analyses only available for the standard case when inflation is followed by an era dominated by the energy density of radiation. Quintessential inflation assumes a common origin for inflation and the dark energy of the Universe. In this scenario reheating

Jun Ma, Richard de Grijs, Zhou Fan, Soo-Chang Rey

Mayall II = G1 is one of the most luminous globular clusters (GCs) in M31. Here, we determine its age and mass by comparing multicolor photometry with theoretical stellar population synthesis models. Based on far- and near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHK_s 2MASS data, we construct the most extensive spectral energy distributi

Martial Mazars

A simple molecular model of chiral molecules is presented in this paper : the chiral dipolar hard sphere model. The discriminatory interaction between enantiomers is represented by electrostatic (or magnetic) dipoles-dipoles interactions : short ranged steric repulsion are represented by hard sphere potential and, in each molecule, two point dipoles are loca

Eric Brown, Heinrich M. Jaeger

We report on rheometry measurements to characterize critical behavior in two model shear thickening suspensions: cornstarch in water and glass spheres in oil. The slope of the shear thickening part of the viscosity curve is found to increase dramatically with packing fraction and diverge at a critical packing fraction phi_c. The magnitude of the viscosity an

Mark Hancock, Beverly J. Smith, Curtis Struck, Mark L. Giroux

To search for Tidal Dwarf Galaxies (TDGs) and to study star formation in tidal features, we are conducting a large UV imaging survey of interacting galaxies selected from the Arp (1996) Atlas using the GALEX telescope. As part of that study, we present a GALEX UV and SDSS and SARA optical study of the gas-rich interacting galaxy pair Arp 305 (NGC 4016/7). Th

Osvaldo Osuna Castro, Elmar Wagner

We present other examples illustrating the operator-theoretic approach to invariant integrals on quantum homogeneous spaces developed by Kuersten and the second author. The quantum spaces are chosen such that their coordinate algebras do not admit bounded Hilbert space representations and their self-adjoint generators have continuous spectrum. Operator algeb

Tatiana A. Ivanova, Olaf Lechtenfeld, Alexander D. Popov, Thorsten Rahn

We consider the Yang-Mills flow equations on a reductive coset space G/H and the Yang-Mills equations on the manifold R x G/H. On nonsymmetric coset spaces G/H one can introduce geometric fluxes identified with the torsion of the spin connection. The condition of G-equivariance imposed on the gauge fields reduces the Yang-Mills equations to phi^4-kink equati

Alexander W. Blocker, Pavlos Protopapas, Charles R. Alcock

We present a new approach to the analysis of time symmetry in light curves, such as those in the x-ray at the center of the Scorpius X-1 occultation debate. Our method uses a new parameterization for such events (the bilogistic event profile) and provides a clear, physically relevant characterization of each event&#39;s key features. We also demonstrate a Ma

M. Bordag, V. Nikolaev

We consider the vacuum energy for a configuration of two cylinders and obtain its asymptotic expansion if the radius of one of these cylinders becomes large while the radius of the other one and their separation are kept fixed. We calculate explicitly the next-to-leading order correction to the vacuum energy for the radius of the other cylinder becoming larg

Luis F. Alday, Juan Maldacena

We consider minimal surfaces in three dimensional anti-de-Sitter space that end at the AdS boundary on a polygon given by a sequence of null segments. The problem can be reduced to a certain generalized Sinh-Gordon equation and to SU(2) Hitchin equations. We describe in detail the mathematical problem that needs to be solved. This problem is mathematically t

Jungyeon Cho, A. Lazarian

We present numerical simulations of electron magnetohydrodynamic (EMHD) and electron reduced MHD (ERMHD) turbulence. Comparing scaling relations, we find that both EMHD and ERMHD turbulence show similar spectra and anisotropy. We develop new techniques to study anisotropy of EMHD turbulence. Our detailed study of anisotropy of EMHD turbulence supports our ea

Enrique Hernandez-Lemus

In recent times whole-genome gene expression analysis has turned out to be a highly important tool to study the coordinated function of a very large number of genes within their corresponding cellular environment, especially in relation to phenotypic diversity and disease. A wide variety of methods of quantitative analysis have been developed to cope with hi

Soumik Pal

We derive the joint density of market weights, at fixed times and suitable stopping times, of the volatility-stabilized market models introduced by Fernholz and Karatzas in [Ann. Finan. 1 (2005) 149-177]. The argument rests on computing the exit density of a collection of independent Bessel-square processes of possibly different dimensions from the unit simp

T. R. Geballe, N. Kameswara Rao, Geoffrey C. Clayton

We present high resolution spectra of the five known hydrogen-deficient carbon (HdC) stars in the vicinity of the 10830 Angstrom line of neutral helium. In R Coronae Borealis (RCB) stars the He I line is known to be strong and broad, often with a P Cygni profile, and must be formed in the powerful winds of those stars. RCB stars have similar chemical abundan

Philip F. Hopkins, Martin Elvis

We propose a two-stage model for the effects of feedback from a bright quasar on the cold gas in a galaxy. It is difficult for feedback from near the accretion disk to directly impact dense molecular clouds at ~kpc. But if such feedback can drive a weak wind or outflow in the hot, diffuse ISM (a relatively &#39;easy&#39; task), then in the wake of such an ou