June 2009 arXiv papers — page 34

Jiri Horak, Michal Bursa

We study oscillations of accretion torus with azimuthal magnetic field. For several lowest-order modes we calculate eigenfrequencies and eigenfunctions and calculate corresponding intensity and polarization light curves using advanced ray-tracing methods.

Maria Victoria Rodriguez-Ledesma, Reinhard Mundt, Jochen Eislöffel

Rotational studies at a variety of ages and masses are important for constraining the angular momentum evolution of young stellar objects (YSO). Of particular interest are the very low mass (VLM) stars and brown dwarfs (BDs), because of the significant lack of known rotational periods in that mass range. We provide for the first time information on rotationa

J. Zhang, T. S. Majmudar, A. Tordesillas, R. P. Behringer

This work focuses on the evolution of structure and stress for an experimental system of 2D photoelastic particles that is subjected to multiple cycles of pure shear. Throughout this process, we determine the contact network and the contact forces using particle tracking and photoelastic techniques. These data yield the fabric and stress tensors and the dist

Cristian Danescu-Niculescu-Mizil, Lillian Lee, Richard Ducott

An important part of textual inference is making deductions involving monotonicity, that is, determining whether a given assertion entails restrictions or relaxations of that assertion. For instance, the statement 'We know the epidemic spread quickly' does not entail 'We know the epidemic spread quickly via fleas', but 'We doubt the epide

Anna M. Quider, Max Pettini, Alice E. Shapley, Charles C. Steidel

Taking advantage of strong gravitational lensing, we have recorded the rest-frame UV spectrum of the z = 2.38115 galaxy `The Cosmic Horseshoe' (J1148+1930) at higher resolution and S/N than is currently feasible for unlensed galaxies at z = 2 -3. From the analysis of stellar spectral features, we conclude that a continuous mode of star formation with a S

Aidan C Crook, Alessandra Silvestri, Phillip Zukin

The peculiar velocity of the Local Group, reconstructed from inhomogeneities in the local density field, differs in direction and magnitude from the velocity inferred from the Cosmic Microwave Background dipole. We investigate whether generalized theories of gravity, which predict a modified growth of perturbations, are able to alleviate this discrepancy. We

Vladimir S. Matveev

We generalize for pseudo-Riemannian metrics a classical result of Gallot and Tanno and use it to reprove a recent result of Alekseevsky, Cortes, Galaev and Leistner that decomposable cones over complete closed pseudo-Riemannian manifolds do not exist.

T. M. Adamo, E. T. Newman

In classical electromagnetic theory, one formally defines the complex dipole moment (the electric plus 'i' magnetic dipole) and then computes (and defines) the complex center of charge by transforming to a complex frame where the complex dipole moment vanishes. Analogously in asymptotically flat space-times it has been shown that one can determine th

Jeremy Wade

We study the convergence of a discretized Fourier orthogonal expansion in orthogonal polynomials on $B^2 \times [-1,1]$, where $B^2$ is the closed unit disk in $\RR^2$. The discretized expansion uses a finite set of Radon projections and provides an algorithm for reconstructing three dimensional images in computed tomography. The Lebesgue constant is shown t

Benjamin P. Brown, Matthew K. Browning, Mark S. Miesch, Allan Sacha Brun

When our Sun was young it rotated much more rapidly than now. Observations of young, rapidly rotating stars indicate that many possess substantial magnetic activity and strong axisymmetric magnetic fields. We conduct simulations of dynamo action in rapidly rotating suns with the 3-D MHD anelastic spherical harmonic (ASH) code to explore the complex coupling

Gregory Gabadadze

Arguments are summarized, that neutral matter made of helium, carbon, etc., should form a quantum liquid at the above-atomic but below-nuclear densities for which the charged spin-0 nuclei can condense. The resulting substance has distinctive features, such as a mass gap in the bosonic sector and a gap-less spectrum of quasifermions, which determine its ther

Jesper Rasmussen, Trevor J. Ponman

We investigate the history of galactic feedback and chemical enrichment within a sample of 15 X-ray bright groups of galaxies, on the basis of the inferred Fe and Si distributions in the hot gas and the associated metal masses produced by core-collapse and type Ia supernovae (SN). Most of these cool-core groups show a central Fe and Si excess, which can be e

Norman Cruz, Samuel Lepe, Francisco Pena, Joel Saavedra

An effective fluid description, for a brane world model in five dimensions, is discussed for both signs of the brane tension. We found several cosmological scenarios where the effective equation differs widely from the bare equation of state. For universes with negative brane tension, with a bare fluid satisfying the strong energy condition, the effective fl

B. Riaz

We present a compositional analysis of the 10 micron silicate spectra for brown dwarf disks in the Taurus and Upper Scorpius (UppSco) star-forming regions, using archival Spitzer/IRS observations. A variety in the silicate features is observed, ranging from a narrow profile with a peak at 9.8 micron, to nearly flat, low-contrast features. For most objects, w

H. Esbensen, C. L. Jiang

Fusion data for $^{48}$Ca+$^{96}$Zr are analyzed by coupled-channels calculations. Puzzling features of a previous analysis are eliminated by applying a potential that has a shallow pocket in the entrance channel. Thus the observed $S$ factor for fusion, which develops a maximum at low energy, can be reproduced fairly well. The high-energy data can also be a

David Garofalo

We study the spin dependence of accretion onto rotating Kerr black holes using analytic techniques. In its linear regime, angular momentum transport in MHD turbulent accretion flow involves the generation of radial magnetic field connecting plasma in a differentially rotating flow. We take a first principles approach, highlighting the constraint that limits

E. Abrahamsson, S. S. Plotkin

Biomolecule Visualization with Ellipsoidal Coarse-graining (BioVEC) is a tool for visualizing molecular dynamics simulation data while allowing coarse-grained residues to be rendered as ellipsoids. BioVEC reads in configuration files, which may be output from molecular dynamics simulations that include orientation output in either quaternion or ANISOU format

Chandra Chekuri, Sungjin Im, Benjamin Moseley

We consider online algorithms for broadcast scheduling. In the pull-based broadcast model there are $n$ unit-sized pages of information at a server and requests arrive online for pages. When the server transmits a page $p$, all outstanding requests for that page are satisfied. The longest-wait-first} (LWF) algorithm is a natural algorithm that has been shown

V. K. Ignatovich, L. T. N. Phan

We consider in a simple and general way elastic waves in isotropic and anisotropic media, their polarization, speeds, reflection from interfaces with mode conversion, and surface waves. Reflection of quasi transverse waves in anisotropic media from a free surface is shown to be characterized by three critical angles.

I. Balantsev, Yu. Popov, A. Studenikin

After a brief discussion on neutrino electromagnetic properties, we consider the problem of neutrino energy spectra in different media. It is shown that in two particular cases (i.e., neutrino propagation in a) transversally moving with increasing speed medium and b) rotating medium) neutrino energies are quantized. These phenomena can be important for astro

A. H. Córsico, L. G. Althaus, M. M. Miller Bertolami, J. M. González Pérez

We present a pulsational stability analysis of hot post-AGB H-deficient pre-white dwarf stars with active He-burning shells. The stellar models employed are state-of-the-art equilibrium structures representative of PG1159 stars derived from the complete evolution of the progenitor stars. On the basis of fully nonadiabatic pulsation computations, we confirmed

Sydney A. Barnes

The construction of all age indicators consists of certain basic steps which lead to the identification of the properties desirable for stellar age indicators. Prior age indicators for main sequence field stars possess only some of these properties. The measured rotation periods of cool stars are particularly useful in this respect because they have well-def

Guglielmo Fucci

In the first part of this Dissertation, we study non-perturbative aspects of quantum electrodynamics on Riemannian manifolds by using heat kernel asymptotic expansion techniques. Here, we established the existence of a new non-perturbative heat kernel asymptotic expansion for a Laplace type operator on homogeneous Abelian bundles with parallel curvature, and

Oscar J. C. Dias, Harvey S. Reall, Jorge E. Santos

Motivated by the Kerr-CFT conjecture, we investigate perturbations of the near-horizon extreme Kerr spacetime. The Teukolsky equation for a massless field of arbitrary spin is solved. Solutions fall into two classes: normal modes and traveling waves. Imposing suitable (outgoing) boundary conditions, we find that there are no unstable modes. The explicit form

Marcel Ausloos, Janusz Miskiewicz

The Theil index is much used in economy and finance; it looks like the Shannon entropy, but pertains to event values rather than to their probabilities. Any time series can be remapped through the Theil index. Correlation coefficients can be evaluated between the new time series, thereby allowing to study their mutual statistical distance, - to be contrasted

Dan Ciubotaru, Peter E. Trapa

We define exact functors from categories of Harish-Chandra modules for certain real classical groups to finite-dimensional modules over an associated graded affine Hecke algebra with parameters. We then study some of the basic properties of these functors. In particular, we show that they map irreducible spherical representations to irreducible spherical rep

Jing Zhu, Zhen Huang, Sabre Kais

Finding the optimal solution to a complex optimization problem is of great importance in practically all fields of science, technology, technical design and econometrics. We demonstrate that a modified Grover's quantum algorithm can be applied to real problems of finding a global minimum using modest numbers of quantum bits. Calculations of the global mi

Cristian Ortiz

We study multiplicative Dirac structures on Lie groups. We show that the characteristic foliation of a multiplicative Dirac structure is given by the cosets of a normal Lie subgroup and, whenever this subgroup is closed, the leaf space inherits the structure of a Poisson-Lie group. We also describe multiplicative Dirac structures on Lie groups infinitesimall

Ido Tal, Ron M. Roth

A method for bounding the rate of bit-stuffing encoders for 2-D constraints is presented. Instead of considering the original encoder, we consider a related one which is quasi-stationary. We use the quasi-stationary property in order to formulate linear requirements that must hold on the probabilities of the constrained arrays that are generated by the encod

Aniruddha Konar, Debdeep Jena

The dielectric environment of thin semiconductor nanowires can affect the charge transport properties inside the wire. In this work, it is shown that Coulomb impurity scattering inside thin nanowires can be damped strongly by coating the wire with a high-k dielectric. This will lead to an increase in the mobility of free charges inside the wire.

Andreas Maletti, Catalin Ionut Tirnauca

We study the class of quasi-alphabetic relations, i.e., tree transformations defined by tree bimorphisms with two quasi-alphabetic tree homomorphisms and a regular tree language. We present a canonical representation of these relations; as an immediate consequence, we get the closure under union. Also, we show that they are not closed under intersection and

Robert S. Whitney

We briefly review three ways that environmental noise can slow-down (or speed-up) quantum transitions; (i) Lamb shifts, (ii) over-damping and (iii) orthogonality catastrophe. We compare them with the quantum Zeno effect induced by observing the system. These effects are relevant to poor qubits (those strongly coupled to noise). We discuss Berry phases genera

R. Cowsik, B. Burch

The observations of the total electronic component and the positron fraction in cosmic rays by the FERMI, HESS, ATIC, and PAMELA instruments are studied with analytical propagation models, both for a set of discrete sources and for a spatially smooth source distribution. The positron fraction over the entire energy range of ~1-100 GeV is shown to fit with th

Ines Safi

We develop a general out-of-equilibrium framework for a typical three-terminal setup of common use: an injector, which can be interacting, coupled by both extended tunneling and Coulomb interactions to an inhomogeneous wire with any range of interactions and scattering processes. Some of the crucial results we obtain are of relevance to other muti-terminal g

Uwe Franz, Adam Skalski

We show that idempotent states on finite quantum groups correspond to pre-subgroups in the sense of Baaj, Blanchard, and Skandalis. It follows that the lattices formed by the idempotent states on a finite quantum group and by its coidalgebras are isomorphic. We show furthermore that these lattices are also isomorphic for compact quantum groups, if one restri

Rosa M. B. Chaves, Martha P. Dussan, Martin Magid

We introduce a new approach to the study of timelike minimal surfaces in the Lorentz-Minkowski space through a split-complex representation formula for this kind of surface. As applications, we solve the Björling problem for timelike surfaces and obtain interesting examples and related results. Using the Björling representation, we also obtain characterizati

Richard A. Wade, M. A. Stark, Richard F. Green, Patrick R. Durrell

The hot subdwarf (sd) stars in the Palomar Green (PG) catalog of ultraviolet excess (UVX) objects play a key role in investigations of the frequency and types of binary companions and the distribution of orbital periods. These are important for establishing whether and by which channels the sd stars arise from interactions in close binary systems. It has bee

The Pierre Auger Collaboration, J. Abraham, P. Abreu, M. Aglietta

Reports on the atmospheric monitoring, calibration, and other operating systems of the Pierre Auger Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.

F. De Vieilleville, Jacques-Olivier Lachaud

This paper presents new results about digital straight segments, their recognition and related properties. They come from the study of the arithmetically based recognition algorithm proposed by I. Debled-Rennesson and J.-P. Reveillès in 1995 [Debled95]. We indeed exhibit the relations describing the possible changes in the parameters of the digital straight

Matteo Martinelli, Alessandro Melchiorri, Luca Amendola

In this paper we place new constraints on a f(R) modified gravity model recently proposed by Hu and Sawicki. After checking that the Hu and Sawicki model produces a viable cosmology, i.e. a matter dominated epoch followed by a late-time acceleration, we constrain some of its parameters by using recent observations from the UNION compilation of luminosity dis

R. Ramelli, M. Bianda, J. O. Stenflo, P. Jetzer

The Zurich IMaging POLarimeter (ZIMPOL) developed at ETH Zurich and installed permanently at the Gregory Coude Telescope at Istituto Ricerche Solari Locarno (IRSOL) allows a polarimetric precision down to 10^-5 to be reached. This makes it possible to perform several accurate spectro-polarimetric measurements of scattering polarization and to investigate sol

Maths Karlsson, Dennis Engberg, Mårten E. Björketun, Aleksandar Matic

We demonstrate the applicability of studying the proton dynamics in proton-conducting perovskites using neutron spin-echo spectroscopy, a powerful method hitherto neglected for studies of the proton dynamics in ceramic proton conductors. By combining our neutron spin-echo results of hydrated BaZr0.90Y0.10O2.95 with results obtained from kinetic modeling base

Wolfgang Reichel, Tobias Weth

We consider the $2m$-th order elliptic boundary value problem $Lu=f(x,u)$ on a bounded smooth domain $Ω\subset\R^N$ with Dirichlet boundary conditions on $\partialΩ$. The operator $L$ is a uniformly elliptic linear operator of order $2m$ whose principle part is of the form $\big(-\sum_{i,j=1}^N a_{ij}(x) \frac{\partial^2}{\partial x_i\partial x_j}\big)^m$. W

Tetsuya Onogi

I review the recent progress in lattice QCD, which will be useful in heavy quark physics in the near future. Reviewing the theoretical developments in lattice QCD first, I focus our recent unquenched QCD with dynamical overlap fermion as implemented by JLQCD collaboration. I also introduce some of our recent studies on the B^*Bπcoupling and on the determinat

R. Ramelli, M. Bianda, J. Trujillo Bueno, L. Merenda

A large set of high precision full-Stokes spectropolarimetric observations of prominences in He-D3, Halpha and Hbeta lines has been recorded with the ZIMPOL polarimeter at the Gregory-Coude Telescope in Locarno. The observational technique allows us to obtain measurements free from seeing induced spurious effects. The instrumental polarization is well under

Dawn B. Woodard, Scott C. Schmidler, Mark Huber

We give conditions under which a Markov chain constructed via parallel or simulated tempering is guaranteed to be rapidly mixing, which are applicable to a wide range of multimodal distributions arising in Bayesian statistical inference and statistical mechanics. We provide lower bounds on the spectral gaps of parallel and simulated tempering. These bounds i

R. Ramelli, M. Bianda, L. Merenda, J. Trujillo Bueno

A large set of high precision full-Stokes spectropolarimetric observations of the He-D3 line in spicules has been recorded with the ZIMPOL polarimeter at the Gregory-Coude Telescope in Locarno. The observational technique allow us to obtain measurements free from seeing induced spurious effects. The instrumental polarization is well under control and taken i

G Beutier, E Ovchinnikova, S P Collins, V E Dmitrienko

'Forbidden' Bragg reflections of iron orthoborate Fe3BO6 were studied theoretically and experimentally in the vicinity of the iron K edge. Their energy spectra are explained as resulting from the interference of x-rays scattered from two inequivalent crystallographic sites occupied by iron ions. This particular structure property gives rise to comple

Clement Touya, David S. Dean, Clement Sire

We study the Langevin dynamics of a dipole diffusing in a random electrical field E derived from a quenched Gaussian potential. We show that in a suitable adiabatic limit (where the dynamics of the dipole moment is much faster than the dynamics of its position), one can reduce the coupled stochastic equations to an effective Langevin equation for a particle

M. Bhuyan, S. K. Patra, P. Arumugam, Raj K. Gupta

We study the clustering structure and the internal or sub-structure of clusters in $^{112-122}$Ba nuclei within the framework of relativistic mean field theory in an axially deformed cylindrical co-ordinate. We calculate the total density distribution, and the individual neutrons and protons density distributions. From the analysis of the clustering confugur

Yannis G. Yatracos

In a sample variance decomposition, with components functions of the sample's spacings, the largest component $\tilde{I}_n$ is used in cluster detection. It is shown for normal samples that the asymptotic distribution of $\tilde{I}_n$ is the Gumbel distribution.

C. G. M. Hermse

Many ordered adlayer structures have been reported for CO on the (100) surfaces of Pt, Rh, Pd, Ni and Cu. Also, some ordered structures are known for NO on the same surfaces. The current review includes all those articles that give a graphical representation of the position of the adsorbates inside the unit cell. The emphasis is on the case of CO on Pt(100)

Natasha Rozhkovskaya

Analogues of classical combinatorial identities for elementary and homogeneous symmetric functions with coefficients in Yanigian are discussed. As a corollary, similar relations are deduced for shifted Schur functions.

M. Bianda, R. Ramelli, D. Gisler

The history of the IRSOL observatory is closely related to Second Solar Spectrum observations. Already in 1963 Brueckner observed scattering polarization in the CaI 4227A line. In 1996 the Hanle effect in the quiet chromosphere was measured for the first time in Locarno using the same spectral line. Since 1998 the ZIMPOL system, a polarimeter allowing unprec

V. Dmitrasinovic, T. Sato, M. Suvakov

We calculate the energies of three-quark states with definite permutation symmetry (i.e. of SU(6) multiplets) in the N=0,1,2 shells, confined by the Y-string three-quark potential. The exact Y-string potential consists of one, so-called three-string term, and three angle-dependent two-string terms. Due to this technical complication we treat the problem at t

C. Girerd, D. Autiero, B. Carlus, S. Gardien

Large LAr TPCs are among the most powerful detectors to address open problems in particle and astro-particle physics, such as CP violation in leptonic sector, neutrino properties and their astrophysical implications, proton decay search etc. The scale of such detector implies severe constraints on their readout and DAQ system. In this article we describe a d

Yacine Aït-Sahalia, Julio Cacho-Diaz, T. R. Hurd

We analyze the consumption-portfolio selection problem of an investor facing both Brownian and jump risks. We bring new tools, in the form of orthogonal decompositions, to bear on the problem in order to determine the optimal portfolio in closed form. We show that the optimal policy is for the investor to focus on controlling his exposure to the jump risk, w

Laura Thevenard, Dorothee Petit, Huang T. Zeng, Russell P. Cowburn

Six-fold configurational anisotropy was studied in Permalloy triangles, in which the shape symmetry order yields two energetically non-degenerate micromagnetic configurations of the spins, the so-called "Y" and "buckle" states. A twelve pointed switching astroid was measured using magneto-optical experiments and successfully reproduced numeri

Min Chen, Tong-Pu Yu, Alexander Pukhov, Zheng-Ming Sheng

When a circularly polarized laser pulse interacts with a foil target, there are three stages: pre-hole-boring, hole-boring and the light sail acceleration. We study the electron and ion dynamics in the first stage and find the minimum foil thickness requirement for a given laser intensity. Based on this analysis, we propose to use a shaped foil for ion accel

R. Ramelli, M. Bianda, J. Trujillo Bueno, L. Belluzzi

We show a selection of high-sensitivity spectropolarimetric observations obtained over the last few years in the Ba II D2-line with the Zurich Imaging Polarimeter (ZIMPOL) attached to the Gregory Coude Telescope of IRSOL. The measurements were collected close to the solar limb, in several regions with varying degree of magnetic activity. The Stokes profiles

Robert A. Jarrow, Philip Protter, Hasanjan Sayit

We show that with suitable restrictions on allowable trading strategies, one has no arbitrage in settings where the traditional theory would admit arbitrage possibilities. In particular, price processes that are not semimartingales are possible in our setting, for example, fractional Brownian motion.

Alexej Weber, Holger Gies

We provide further evidence for the nontrivial interplay between geometry and temperature in the Casimir effect. We investigate the temperature dependence of the Casimir force between an inclined semi-infinite plate above an infinite plate in D dimensions using the worldline formalism. Whereas the high-temperature behavior is always found to be linear in T i

Saumyadip Samui, Raghunathan Srianand, Kandaswamy Subramanian

We present a semi-analytical model of star formation which explains simultaneously the observed UV luminosity function of high redshift Lyman break galaxies (LBGs) and luminosity functions of Lyman-alpha emitters. We consider both models that use the Press-Schechter (PS) and Sheth-Tormen (ST) halo mass functions to calculate the abundances of dark matter hal

Gargi Shaw, G. J. Ferland, W. J. Henney, P. C. Stancil

The Orion Bar is one of the nearest and best-studied photodissociation or photon-dominated regions (PDRs). Observations reveal the presence of H2 lines from vibrationally or rotationally excited upper levels that suggest warm gas temperatures (400 to 700 K). However, standard models of PDRs are unable to reproduce such warm rotational temperatures. In this p

The HADES Collaboration, P. Tlusty, G. Agakishiev, A. Balanda

Results of a study of charged pion production in 12C+12C collisions at incident beam energies of 1A GeV and 2A GeV, and 40Ar+natKCl at 1.76AGeV, using the spectrometer HADES at GSI, are presented. We have performed a measurement of the transverse momentum distributions of pi+- mesons covering a fairly large rapidity interval, in case of the C+C collision sys

C. E. Fischer, A. G. de Wijn, R. Centeno, B. W. Lites

Aims. Convective collapse, a theoretically predicted process that intensifies existing weak magnetic fields in the solar atmosphere, was first directly observed in a single event by Nagata et al. (2008) using the high resolution Solar Optical Telescope (SOT) of the Hinode satellite. Using the same space telescope, we performed a statistical analysis of conve

Mauro Cherubini, Rodrigo de Oliveira, Nuria Oliver

We conducted a qualitative user study with 77 consumers to investigate what social aspects are relevant when supporting customers during their shopping activities and particularly in situations when they are undecided. Twenty-five respondents (32%) reported seeking extra information on web pages and forums, in addition to asking their peers for advice (relat

Chris Fields

Decompositions of the world into systems have typically been regarded as arbitrary extra-theoretical assumptions in discussions of quantum measurement. One can instead regard decompositions as part of the theory, and ask what conditions they must satisfy for self-consistency. It is shown that self-consistent decompositions that specify a measurement context

Rami Atar, Gennady Shaikhet

This paper introduces and analyzes the notion of throughput suboptimality for many-server queueing systems in heavy traffic. The queueing model under consideration has multiple customer classes, indexed by a finite set $\mathcal{I}$, and heterogenous, exponential servers. Servers are dynamically chosen to serve customers, and buffers are available for custom

V. V. Efimov, M. V. Shokurov, D. A. Yarovaya, D. Hein

Results of regional climate modeling PRECIS with high spatial resolution (25 km) were used to investigate mesoscale features of atmospheric circulation in the Black Sea Region for 30-yr period. Method based on Ocubo-Weiss criterion was used to detect and track subsynoptic eddies. Several types of cyclonic eddy were discovered and studied: winter Caucasian co

M. N. Stoilov

Anomalous quantisation of instantons allows non-trivial (anti) self-dual configurations to exist for pure U(2) gauge theory in four-dimensional Euclidean space-time and to be used as ground state of the model. Six left fermions together with six right fermions and one complex scalar doublet describe the largest possible vacuum. This structure is just enough

J. Fernandez Nunez, W. Garcia Fuertes, A. M. Perelomov

We provide a list of explicit eigenfunctions of the trigonometric Calogero-Sutherland Hamiltonian associated to the root system of the exceptional Lie algebra E8. The quantum numbers of these solutions correspond to the first and second order weights of the Lie algebra.

Pablo Ramacher

This is the second of a series of papers dealing with the asymptotic behavior of certain integrals occuring in the description of the spectrum of an invariant elliptic operator on a compact Riemannian manifold carrying the action of a compact, connected Lie group of isometries, and in the study of its equivariant cohomology via the moment map.

Satoshi Masaki

We consider the semiclassical Schrödinger-Poisson system with a special initial data of WKB type such that the solution of the limiting hydrodynamical equation becomes time-global in dimensions at least three. We give an example of such initial data in the focusing case via the analysis of the compressible Euler-Poisson equations. This example is a large dat

El Maati Ouhabaz, Chiara Spina

In this paper we study the maximal regularity property for non-autonomous evolution equations $\partial_t u(t)+A(t)u(t)=f(t), u(0)=0.$ If the equation is considered on a Hilbert space $H$ and the operators $A(t)$ are defined by sesquilinear forms $ a(t,.,.)$ we prove the maximal regularity under a Holder continuity assumption of $t \to a(t,.,.)$. In the non-

Rick Durrett

In this paper I will review twenty years of work on the question: When is there coexistence in stochastic spatial models? The answer, announced in Durrett and Levin [Theor. Pop. Biol. 46 (1994) 363--394], and that we explain in this paper is that this can be determined by examining the mean-field ODE. There are a number of rigorous results in support of this

G. W. Fuchs, H. M. Cuppen, S. Ioppolo, C. Romanzin

Hydrogenation reactions of CO in inter- and circumstellar ices are regarded as an important starting point in the formation of more complex species. Previous laboratory measurements by two groups on the hydrogenation of CO ices resulted in controversial results on the formation rate of methanol. Our aim is to resolve this controversy by an independent invest

Satoshi Masaki

We give a necessary and sufficient condition for the global existence of the classical solution to the Cauchy problem of the compressible Euler-Poisson equations with radial symmetry. We introduce a new quantity which describes the balance between the initial velocity of the flow and the strength of the force governed by Poisson equation.

P. Castorina, J. Cleymans, D. E. Miller, H. Satz

We calculate the speed of sound $c_s$ in an ideal gas of resonances whose mass spectrum is assumed to have the Hagedorn form $ρ(m) \sim m^{-a}\exp{bm}$, which leads to singular behavior at the critical temperature $T_c = 1/b$. With $a = 4$ the pressure and the energy density remain finite at $T_c$, while the specific heat diverges there. As a function of the

A. Bussmann-Holder, A. Simon, H. Keller, A. R. Bishop

By interpreting various experimental data for the new high temperature FeAs type superconductors in terms of lattice mediated multi gap superconductivity, it is shown that these systems strongly resemble MgB2, however, with the distinction that local polaronic lattice effects exist. This fact establishes a connection to cuprate high temperature superconducto

Cyril Georgy, Georges Meynet, Rolf Walder, Doris Folini

We discuss the properties of the progenitors of core collapse SNe, as they can be deduced from rotating stellar models of single stars. The type of the SN progenitor was determined from the surface abundances at the pre-SN stage. The type of the SN event was obtained from the masses of hydrogen and helium ejected at the time of the core-collapse SN event. We

A. Bussmann-Holder, A. Simon, H. Keller, A. R. Bishop

The temperature dependencies of the coupled superconducting gaps, observed in Fe-As based superconducting compounds is calculated and a universal temperature scaling observed which is only present if the coupled order parameters both have s-wave symmetry. Predictions for possible isotope effects on the transition temperature are made if phonons are involved

Cristina Bena

We study the Fourier transform of the local density of states (LDOS) in graphene in the presence of a single impurity at high magnetic field. We find that the most pronounced features occur for energies of the STM tip matching the Landau level energies. The Fourier transform of the LDOS shows regions of high intensity centered around the center and the corne

Thierry Rabilloud

Despite decades of extensive research, the large-scale analysis of membrane proteins remains a difficult task. This is due to the fact that membrane proteins require a carefully balanced hydrophilic and lipophilic environment, which optimum varies with different proteins, while most protein chemistry methods work mainly, if not only, in water-based media. Ta

Aldéric Joulin

The purpose of this paper is to extend the investigation of Poisson-type deviation inequalities started by Joulin (Bernoulli 13 (2007) 782--798) to the empirical mean of positively curved Markov jump processes. In particular, our main result generalizes the tail estimates given by Lezaud (Ann. Appl. Probab. 8 (1998) 849--867, ESAIM Probab. Statist. 5 (2001)

Eef van Beveren, George Rupp

Data on B+ --> J/psi phi K+ and the Y(4140) enhancement recently reported by the CDF collaboration [arxiv:0903.2229] are analysed. The threshold behaviour, as well as traces of the X(4260) enhancement, the known c-cbar resonances psi(2D), psi(4S), and a tentative psi(3D) state, as observed in the mass distribution, suggest that the J/psi+phi system has quant

Vo V. Anh, Nikolai N. Leonenko, Narn-Rueih Shieh

We investigate the scaling properties of products of the exponential of birth--death processes with certain given marginal discrete distributions and covariance structures. The conditions on the mean, variance and covariance functions of the resulting cumulative processes are interpreted in terms of the moment generating functions. We provide four illustrati

F. D. Czeschka, S. Gepraegs, M. Opel, S. T. B. Goennenwein

The integration of ferromagnetic and ferroelectric materials into hybrid heterostructures yields multifunctional systems with improved or novel functionality. We here report on the structural, electronic and magnetic properties of the ferromagnetic double perovskite Sr2CrReO6, grown as epitaxial thin film onto ferroelectric BaTiO3. As a function of temperatu

C. Durot, E. Lebarbier, A. -S. Tocquet

Assume one observes independent categorical variables or, equivalently, one observes the corresponding multinomial variables. Estimating the distribution of the observed sequence amounts to estimating the expectation of the multinomial sequence. A new estimator for this mean is proposed that is nonparametric, non-asymptotic and implementable even for large s

Dženan Zukić, Christof Rezk-Salama, Andreas Kolb

Many state-of-the art visualization techniques must be tailored to the specific type of dataset, its modality (CT, MRI, etc.), the recorded object or anatomical region (head, spine, abdomen, etc.) and other parameters related to the data acquisition process. While parts of the information (imaging modality and acquisition sequence) may be obtained from the m

Carl Lindberg

It is widely recognized that when classical optimal strategies are applied with parameters estimated from data, the resulting portfolio weights are remarkably volatile and unstable over time. The predominant explanation for this is the difficulty of estimating expected returns accurately. In this paper, we modify the $n$ stock Black--Scholes model by introdu

D. V. Tokarev, K. A. Borovkov

Let $X^1, ..., X^k$ and $Y^1, ..., Y^m$ be jointly independent copies of random variables $X$ and $Y$, respectively. For a fixed total number $n$ of random variables, we aim at maximising $M(k,m):= E \max \{X^1, ..., X^k, Y^1, >..., Y^{m} \}$ in $k = n-m\ge 0$, which corresponds to maximising the expected lifetime of an $n$-component parallel system whose co

W. van Driel

The radio spectrum is a finite and increasingly precious resource for astronomical research, as well as for other spectrum users. Keeping the frequency bands used for radio astronomy as free as possible of unwanted Radio Frequency Interference (RFI) is crucial. The aim of spectrum management, one of the tools used towards achieving this goal, includes settin

Ching-Kang Ing, Jin-Lung Lin, Shu-Hui Yu

This paper investigates multistep prediction errors for non-stationary autoregressive processes with both model order and true parameters unknown. We give asymptotic expressions for the multistep mean squared prediction errors and accumulated prediction errors of two important methods, plug-in and direct prediction. These expressions not only characterize ho

Jiao Wang, Jiangbin Gong

The Floquet spectrum of a class of driven SU(2) systems is shown to display a butterfly pattern with multi-fractal properties. The level crossing between Floquet states of the same parity or different parities is studied. The results are relevant to studies of fractal statistics, quantum chaos, coherent destruction of tunneling, and the validity of mean-fiel

J. G. Hartnett, D. Mouneyrac, J. -M. Le Floch, J. Krupka

Whispering Gallery modes in bulk cylindrical Gallium Arsenide and Gallium Phosphide samples have been examined both in darkness and under white light at cryogenics temperatures < 50 K. In both cases persistent photoconductivity was observed after initially exposing semiconductors to white light from a halogen lamp. Photoconductance decay time constants for G

Jiao Wang, Jiangbin Gong

A scheme for generating a fractal butterfly Floquet spectrum, first proposed by Wang and Gong [Phys. Rev. A {\bf 77}, 031405(R) (2008)], is extended to driven SU(2) systems such as a driven two-mode Bose-Einstein condensate. A new class of driven systems without a link with the Harper model context is shown to have an intriguing butterfly Floquet spectrum. T

Zhangjin Chen, T. Wittmann, C. D. Lin

An all non-optical method for accurately determining the pulse parameters of individual few-cycle laser shots is presented. By analyzing the &#34;left&#34; and &#34;right&#34; asymmetry of high-energy photoelectrons along the polarization axis using the recently developed quantitative rescattering theory, we show that the carrier-envelope phase, the pulse du

R. Alexander Bentley, Paul Ormerod

Two general patterns have been identified for the adoption and subsequent abandonment of ideas or products within a population. One is symmetric, so that concepts or products which are adopted rapidly then decline rapidly from their peak, and those which are slower to move to their peak decline more slowly. The other is asymmetric, where the decline from the

Chinmay S. Vaze, Mahesh K. Varanasi

A Dirty Paper Coding (DPC) based transmission scheme for the Gaussian multiple-input multiple-output (MIMO) cognitive radio channel (CRC) is studied when there is imperfect and perfect channel knowledge at the transmitters (CSIT) and the receivers, respectively. In particular, the problem of optimizing the sum-rate of the MIMO CRC over the transmit covarianc