title:
On the relation between mass of pion, fundamental physical constants and
  cosmological parameters

abstract:
  In this article we reconsider the old mysterious relation, advocated by Dirac
and Weinberg, between the mass of the pion, the fundamental physical constants,
and the Hubble parameter. By introducing the cosmological density parameters,
we show how the corresponding equation may be written in a form that is
invariant with respect to the expansion of the Universe and without invoking a
varying gravitational "constant", as was originaly proposed by Dirac. It is
suggest that, through this relation, Nature gives a hint that virtual pions
dominante the "content" of the quantum vacuum.


title: The magnetoresistance tensor of La(0.8)Sr(0.2)MnO(3)

abstract:
  We measure the temperature dependence of the anisotropic magnetoresistance
(AMR) and the planar Hall effect (PHE) in c-axis oriented epitaxial thin films
of La(0.8)Sr(0.2)MnO(3), for different current directions relative to the
crystal axes, and show that both AMR and PHE depend strongly on current
orientation. We determine a magnetoresistance tensor, extracted to 4th order,
which reflects the crystal symmetry and provides a comprehensive description of
the data. We extend the applicability of the extracted tensor by determining
the bi-axial magnetocrystalline anisotropy in our samples.


title:
Cooperation of Sperm in Two Dimensions: Synchronization, Attraction and
  Aggregation through Hydrodynamic Interactions

abstract:
  Sperm swimming at low Reynolds number have strong hydrodynamic interactions
when their concentration is high in vivo or near substrates in vitro. The
beating tails not only propel the sperm through a fluid, but also create flow
fields through which sperm interact with each other. We study the hydrodynamic
interaction and cooperation of sperm embedded in a two-dimensional fluid by
using a particle-based mesoscopic simulation method, multi-particle collision
dynamics (MPC). We analyze the sperm behavior by investigating the relationship
between the beating-phase difference and the relative sperm position, as well
as the energy consumption. Two effects of hydrodynamic interaction are found,
synchronization and attraction. With these hydrodynamic effects, a multi-sperm
system shows swarm behavior with a power-law dependence of the average cluster
size on the width of the distribution of beating frequencies.


title: Dynamical properties of quasiparticles in a gapped graphene sheet

abstract:
  We present numerical calculations of the impact of charge carriers-carriers
interactions on the dynamical properties of quasiparticles such as renormalized
velocity and quasiparticle inelastic scattering lifetime in a gapped graphene
sheet. Our formalism is based on the many-body $G_0W$-approximation for the
self-energy. We present results for the many-body renormalized velocity
suppression and the renormalization constant over a broad range of energy gap
values. We find that the renormalized velocity is almost independence of the
carrier densities at large density regime. We also show that the quasiparticle
inelastic scattering lifetime decreases by increasing the gap value. Finally,
we present results for the mean free path of charge carriers suppression over
the energy gap values.


title: Spin Probe ESR Signature of Freezing in Water: Is it Global or Local?

abstract:
  First systematic spin probe ESR study of water freezing has been conducted
using TEMPOL and TEMPO as the probes. The spin probe signature of the water
freezing has been described in terms of the collapse of narrow triplet spectrum
into a single broad line. This spin probe signature of freezing has been
observed at an anomalously low temperature when a milimoler solution of TEMPOL
is slowly cooled from room temperature. A systematic observation has revealed a
spin probe concentration dependence of these freezing and respective melting
points. These results can be explained in terms of localization of spin probe
and liquid water, most probably in the interstices of ice grains, in an ice
matrix. The lowering of spin probe freezing point, along with the secondary
evidences, like spin probe concentration dependence of peak-to-peak width in
frozen limit signal, indicates a possible size dependence of these
localizations/entrapments with spin probe concentration. A weak concentration
dependence of spin probe assisted freezing and melting points, which has been
observed for TEMPO in comparison to TEMPOL, indicates different natures of
interactions with water of these two probes. This view is also supported by the
relaxation behavior of the two probes.


title: Fluctuations and oscillations in a simple epidemic model

abstract:
  We show that the simplest stochastic epidemiological models with spatial
correlations exhibit two types of oscillatory behaviour in the endemic phase.
In a large parameter range, the oscillations are due to resonant amplification
of stochastic fluctuations, a general mechanism first reported for
predator-prey dynamics. In a narrow range of parameters that includes many
infectious diseases which confer long lasting immunity the oscillations persist
for infinite populations. This effect is apparent in simulations of the
stochastic process in systems of variable size, and can be understood from the
phase diagram of the deterministic pair approximation equations. The two
mechanisms combined play a central role in explaining the ubiquity of
oscillatory behaviour in real data and in simulation results of epidemic and
other related models.


title: Solutions Classification to the Extended Reduced Ostrovsky Equation

abstract:
  An alternative to the Parkes' approach [SIGMA 4 (2008) 053, arXiv:0806.3155]
is suggested for the solutions categorization to the extended reduced Ostrovsky
equation (the exROE in Parkes' terminology). The approach is based on the
application of the qualitative theory of differential equations which includes
a mechanical analogy with the point particle motion in a potential field, the
phase plane method, analysis of homoclinic trajectories and the like. Such an
approach is seemed more vivid and free of some restrictions contained in the
above mentioned Parkes' paper.


title: Static potentials for quarkonia at finite temperatures

abstract:
  We review non-perturbative static potentials commonly used in potential
models for quarkonia at finite T. Potentials derived from Polyakov loop
correlators are shown to be inappropriate for this purpose. The q\bar{q} free
energy is physical but has the wrong spatial decay and perturbative limit. The
so-called singlet free energy is gauge dependent and unphysical. An appropriate
static real time potential can be defined through a generalisation of pNRQCD to
finite T. In perturbation theory, its real part reproduces the Debye-screened
potential, its imaginary part accounts for Landau damping. Possibilities for
its non-perturbative evaluation are discussed.


title: All-angle zero reflection at metamaterial surfaces

abstract:
  The authors study theoretically reflection on the surface of a metamaterial
with a hyperbolic dispersion. It is found that reflection is strongly dependent
on how the surface is terminated with respect to the asymptote of the
hyperbolic dispersion. For a surface terminated normally to the asymptote, zero
reflection occurs for all incident angles. It is exemplified by a metamaterial
made of a periodic metal-dielectric layered structure with its surface properly
cut through numerical simulations.


title: A Cr-K emission line survey in young supernova remnants with Chandra

abstract:
  We performed a Cr-K emission line survey in young supernova remnants (SNRs)
with the Chandra archival data. Our sample includes W49B, Cas A, Tycho and
Kepler. We confirmed the existence of the Cr line in W49B and discovered this
emission line in the other three SNRs. The line center energies, equivalent
widths (EWs) and fluxes of the Cr lines are given. The Cr in Cas A is in a high
ionization state while that in Tycho and Kepler is in a much lower one. We find
a good positive correlation between Cr and Fe line center energies, suggesting
a common origin of Cr and Fe in the nucleosynthesis, which is consistent with
the theoretical predictions. We propose that the EW ratio between Cr and Fe can
be used as a supplementary constraint on the progenitors' properties and the
explosion mechanism.


title:
Cluster Monte Carlo and numerical mean field analysis for the water
  liquid--liquid phase transition

abstract:
  By the Wolff's cluster Monte Carlo simulations and numerical minimization
within a mean field approach, we study the low temperature phase diagram of
water, adopting a cell model that reproduces the known properties of water in
its fluid phases. Both methods allows us to study the water thermodynamic
behavior at temperatures where other numerical approaches --both Monte Carlo
and molecular dynamics-- are seriously hampered by the large increase of the
correlation times. The cluster algorithm also allows us to emphasize that the
liquid--liquid phase transition corresponds to the percolation transition of
tetrahedrally ordered water molecules.


title:
The adjoint potential in the pseudoparticle approach: string breaking
  and Casimir scaling

abstract:
  We perform a detailed study of the adjoint static potential in the
pseudoparticle approach, which is a model for SU(2) Yang-Mills theory. We find
agreement with the Casimir scaling hypothesis and there is clear evidence for
string breaking. At the same time the potential in the fundamental
representation is linear for large separations. Our results are in qualitative
agreement with results from lattice computations.


title:
Principal bifurcations and symmetries in the emergence of
  reaction-diffusion-advection patterns on finite domains

abstract:
  Pattern formation mechanisms of a reaction-diffusion-advection system, with
one diffusivity, differential advection, and (Robin) boundary conditions of
Danckwerts type, are being studied. Pattern selection requires mapping the
domains of coexistence and stability of propagating or stationary nonuniform
solutions, which for the general case of far from instability onsets, is
conducted using spatial dynamics and numerical continuations. The selection is
determined by the boundary conditions which either preserve or destroy the
translational symmetry of the model. Accordingly, we explain the criterion and
the properties of stationary periodic states if the system is bounded and show
that propagation of nonlinear waves (including solitary) against the advective
flow corresponds to coexisting family that emerges nonlinearly from a distinct
oscillatory Hopf instability. Consequently, the resulting pattern selection is
qualitatively different from the symmetric finite wavenumber Turing or Hopf
instabilities.


title: Low regularity for a quadratic Schr\"odinger equation on the circle

abstract:
  In this paper we consider a Schrodinger equation on the circle with a
quadratic nonlinearity. Thanks to an explicit computation of the first Picard
iterate, we give a precision on the dynamic of the solution, whose existence
was proved by C. E. Kenig, G. Ponce and L. Vega. We also show that the equation
is well-posed in a space based on Lp norms in frequencies.


title:
Branes and Quantization for an A-Model Complexification of Einstein
  Gravity in Almost Kahler Variables

abstract:
  The general relativity theory is redefined equivalently in almost Kahler
variables: symplectic form and canonical symplectic connection (distorted from
the Levi-Civita connection by a tensor constructed only from metric
coefficients and their derivatives). The fundamental geometric and physical
objects are uniquely determined in metric compatible form by a (pseudo)
Riemannian metric on a manifold enabled with a necessary type nonholonomic 2+2
distribution. Such nonholonomic symplectic variables allow us to formulate the
problem of quantizing Einstein gravity in terms of the A-model complexification
of almost complex structures on spacetime manifold, generalizing the
Gukov-Witten method, see arXiv:0809.0305. Quantizing the complexified model, we
derive a Hilbert space as a space of strings with two A-branes which for the
Einstein gravity theory are nonholonomic because of induced nonlinear
connection structures. Finally, we speculate on relation of such a method of
quantization to curve flows and solitonic hierarchies defined by Einstein
metrics on (pseudo) Riemannian spacetimes.


title: Development of Glass Resistive Plate Chambers for INO

abstract:
  The India-based Neutrino Observatory (INO) collaboration is planning to build
a massive 50kton magnetised Iron Calorimeter (ICAL) detector, to study
atmospheric neutrinos and to make precision measurements of the parameters
related to neutrino oscillations. Glass Resistive Plate Chambers (RPCs) of
about 2m X 2m in size are going to be used as active elements for the ICAL
detector. We have fabricated a large number of glass RPC prototypes of 1m X 1m
in size and have studied their performance and long term stability. In the
process, we have developed and produced a number of materials and components
required for fabrication of RPCs. We have also designed and optimised a number
of fabrication and quality control procedures for assembling the gas gaps. In
this paper we will review our activities towards development of glass RPCs for
the INO ICAL detector and will present results of the characterisation studies
of the RPCs.


title: Metric aspects of noncommutative homogeneous spaces

abstract:
  For a closed cocompact subgroup $\Gamma$ of a locally compact group $G$,
given a compact abelian subgroup $K$ of $G$ and a homomorphism $\rho:\hat{K}\to
G$ satisfying certain conditions, Landstad and Raeburn constructed equivariant
noncommutative deformations $C^*(\hat{G}/\Gamma, \rho)$ of the homogeneous
space $G/\Gamma$, generalizing Rieffel's construction of quantum Heisenberg
manifolds. We show that when $G$ is a Lie group and $G/\Gamma$ is connected,
given any norm on the Lie algebra of $G$, the seminorm on $C^*(\hat{G}/\Gamma,
\rho)$ induced by the derivation map of the canonical $G$-action defines a
compact quantum metric. Furthermore, it is shown that this compact quantum
metric space depends on $\rho$ continuously, with respect to quantum
Gromov-Hausdorff distances.


title: Smooth approximation of Lipschitz projections

abstract:
  We show that any Lipschitz projection-valued function p on a connected closed
Riemannian manifold can be approximated uniformly by smooth projection-valued
functions q with Lipschitz constant close to that of p. This answers a question
of Rieffel.


title: (Non)triviality of Pure Spinors and Exact Pure Spinor - RNS Map

abstract:
  All the BRST-invariant operators in pure spinor formalism in $d=10$ can be
represented as BRST commutators, such as
$V=\lbrace{Q_{brst}},{{\theta_{+}}\over{\lambda_{+}}}V\rbrace$ where
$\lambda_{+}$ is the U(5) component of the pure spinor transforming as
$1_{5\over2}$. Therefore, in order to secure non-triviality of BRST cohomology
in pure spinor string theory, one has to introduce "small Hilbert space" and
"small operator algebra" for pure spinors, analogous to those existing in RNS
formalism. As any invariant vertex operator in RNS string theory can also
represented as a commutator $V=\lbrace{Q_{brst}},LV\rbrace$ where
$L=-4c\partial\xi{\xi}e^{-2\phi}$, we show that mapping
${{\theta_{+}}\over{\lambda_{+}}}$ to L leads to identification of the pure
spinor variable $\lambda^{\alpha}$ in terms of RNS variables without any
additional non-minimal fields. We construct the RNS operator satisfying all the
properties of $\lambda^\alpha$ and show that the pure spinor BRST operator
$\oint{\lambda^\alpha{d_\alpha}}$ is mapped (up to similarity transformation)
to the BRST operator of RNS theory under such a construction. We also observe
that BRST cohomology of pure spinor superstring theory contains vertex
operators non-trivially coupled to the pure spinor ghost variable. The physical
interpretation of these operators remains unclear.


title:
Group and phase velocities in the free-surface visco-potential flow: new
  kind of boundary layer induced instability

abstract:
  Water wave propagation can be attenuated by various physical mechanisms. One
of the main sources of wave energy dissipation lies in boundary layers. The
present work is entirely devoted to thorough analysis of the dispersion
relation of the novel visco-potential formulation. Namely, in this study we
relax all assumptions of the weak dependence of the wave frequency on time. As
a result, we have to deal with complex integro-differential equations that
describe transient behaviour of the phase and group velocities. Using numerical
computations, we show several snapshots of these important quantities at
different times as functions of the wave number. Good qualitative agreement
with previous study [Dutykh2009] is obtained. Thus, we validate in some sense
approximations made anteriorly. There is an unexpected conclusion of this
study. According to our computations, the bottom boundary layer creates
disintegrating modes in the group velocity. In the same time, the imaginary
part of the phase velocity remains negative for all times. This result can be
interpreted as a new kind of instability which is induced by the bottom
boundary layer effect.

categories: physics.class-ph math.AP math.NA physics.ao-ph physics.comp-ph physics.flu-dyn physics.geo-ph


title: Left-Garside categories, self-distributivity, and braids

abstract:
  In connection with the emerging theory of Garside categories, we develop the
notions of a left-Garside category and of a locally left-Garside monoid. In
this framework, the connection between the self-distributivity law LD and
braids amounts to the result that a certain category associated with LD is a
left-Garside category, which projects onto the standard Garside category of
braids. This approach leads to a realistic program for establishing the
Embedding Conjecture of [Dehornoy, Braids and Self-distributivity, Birkhauser
(2000), Chap. IX].


title:
N=4 Gauged Supergravity from Duality-Twist Compactifications of String
  Theory

abstract:
  We investigate the lifting of half-maximal four-dimensional gauged
supergravities to compactifications of string theory. It is shown that a class
of such supergravities can arise from compactifications of IIA string theory on
manifolds of SU(2)-structure which may be thought of as K3 fibrations over T^2.
Examples of these SU(2)-structure backgrounds, as smooth K3 bundles and as
compactifications with H-flux, are given and we also find evidence for a class
of non-geometric, Mirror-fold backgrounds. By applying the duality between IIA
string theory on K3 and Heterotic string theory on T^4 fibrewise, we argue that
these SU(2)-structure backgrounds are dual to Heterotic compactifications on a
class T^4 fibrations over T^2. Examples of these fibrations as twisted tori,
H-flux and T-fold compactifications are given. We also construct a new set of
backgrounds, particular to Heterotic string theory, which includes a previously
unknown class of Heterotic T-folds. A sigma model description of these
backgrounds, from the Heterotic perspective, is presented in which we
generalize the Bosonic doubled formalism to Heterotic string theory.


title: On nearly radial marginals of high-dimensional probability measures

abstract:
  We prove that any absolutely continuous probability measure on a
high-dimensional linear space has low-dimensional marginals that are
approximately spherically-symmetric.


title: Counting Descents in Standard Young Tableaux

abstract:
  This paper deals with the distribution of descent number in standard Young
tableaux of certain shapes. A simple explicit formula is presented for the
number of tableaux of any shape with two rows, with any specified number of
descents. For shapes of three rows with one cell in the third row recursive
formulas are given, and are solved in certain cases.


title: The topology of chaotic iterations

abstract:
  Chaotic iterations have been introduced on the one hand by Chazan, Mi- ranker
[6] and Miellou [10] in a numerical analysis context, and on the other hand by
Robert [12] and Pellegrin [11] in the discrete dynamical systems frame- work.
In both cases, the objective was to derive conditions of convergence of such
iterations to a fixed state. In this paper, a new point of view is presented,
the goal here is to derive conditions under which chaotic iterations admit a
chaotic behaviour in a rigorous mathematical sense. Contrary to what has been
studied in the literature, convergence is not desired.
  More precisely, we establish in this paper a link between the concept of
chaotic iterations on a finite set and the notion of topological chaos [9],
[7], [8]. We are motivated by concrete applications of our approach, such as
the use of chaotic boolean iterations in the computer security field. Indeed,
the concept of chaos is used in many areas of data security without real
rigorous theoretical foundations, and without using the fundamental properties
that allow chaos. The wish of this paper is to bring a bit more mathematical
rigour in this field. This paper is an extension of[3], and a work in progress.


title:
Complex zero-free regions at large |q| for multivariate Tutte
  polynomials (alias Potts-model partition functions) with general complex edge
  weights

abstract:
  We find zero-free regions in the complex plane at large |q| for the
multivariate Tutte polynomial (also known in statistical mechanics as the
Potts-model partition function) Z_G(q,w) of a graph G with general complex edge
weights w = {w_e}. This generalizes a result of Sokal (cond-mat/9904146) that
applies only within the complex antiferromagnetic regime |1+w_e| \le 1. Our
proof uses the polymer-gas representation of the multivariate Tutte polynomial
together with the Penrose identity.


title:
Suzaku Observations across the Cygnus Loop from the Northeastern to the
  Southwestern Rim

abstract:
  We have observed the Cygnus Loop from the northeast (NE) rim to the southwest
(SW) rim using Suzaku in 10 pointings that is just north of previous XMM-Newton
observations. The observation data obtained were divided into 45 rectangular
regions where the width were configured so that each region holds 8000$-$12000
photons. The spectrum acquired from each region was fitted either with
one-kTe-component non-equilibrium ionization (NEI) model or with
two-kTe-component NEI model. The two-kTe-component model yields significantly
better fit in almost all the non-rim regions. Judging from abundances and flux,
the high-kTe-component (0.4$-$0.8keV) must be the ejecta origin, while the
low-\kTe-component ($\sim$0.3keV) comes from the swept-up matter. We found that
swept-up matter shell is very thin in just southwest of center of the Loop.
Together with previous observations, we estimate the diameter of this thin
shell region to be $1^{\circ}$.
  We also found that the ejecta distributions were asymmteric to the geometric
center: the ejecta of O, Ne and Mg were distributed more in the NE, while the
ejecta of Si and Fe were distributed more in the SW of the Cygnus Loop. We
calculated the masses for various metals and estimated the origin of the Cygnus
Loop as the 12-15M$_\odot$ core-collapse explosion.


title: Iteratively algebraic orders

abstract: A short proof of a theorem of M.H. Albert, and its application to lattices.


title: Control of graphene's properties by reversible hydrogenation

abstract:
  Graphene - a monolayer of carbon atoms densely packed into a hexagonal
lattice - has one of the strongest possible atomic bonds and can be viewed as a
robust atomic-scale scaffold, to which other chemical species can be attached
without destroying it. This notion of graphene as a giant flat molecule that
can be altered chemically is supported by the observation of so-called graphene
oxide, that is graphene densely covered with hydroxyl and other groups.
Unfortunately, graphene oxide is strongly disordered, poorly conductive and
difficult to reduce to the original state. Nevertheless, one can imagine atoms
or molecules being attached to the atomic scaffold in a strictly periodic
manner, which should result in a different electronic structure and,
essentially, a different crystalline material. A hypothetical example for this
is graphane, a wide-gap semiconductor, in which hydrogen is bonded to each
carbon site of graphene. Here we show that by exposing graphene to atomic
hydrogen, it is possible to transform this highly-conductive semimetal into an
insulator. Transmission electron microscopy reveals that the material retains
the hexagonal lattice but its period becomes markedly shorter than that of
graphene, providing direct evidence for a new graphene-based derivative. The
reaction with hydrogen is found to be reversible so that the original metallic
state and lattice spacing are restored by annealing and even the quantum Hall
effect recovers. Our work proves the concept of chemical modification of
graphene, which promises a whole range of new two-dimensional crystals with
designed electronic and other properties.


title: Le theoreme de periodicite en K-theorie hermitienne

abstract:
  Bott periodicity plays an important role in topological K-theory. The purpose
of this paper is to extend the periodicity theorem in a discrete context, where
all classical groups are involved and not just the general linear group. The
present paper generalizes previous results of the author [K1] and [K2], where 2
was assumed to be invertible in the rings involved. For the proof, two
important ideas have to be mentioned : the first one is due to Ranicki [R] who
introduced a kind of "enlarged" orthogonal group ; the second one is a genuine
cup-product between quadratic forms due to Clauwens [C]. As an example of
results obtained, we prove that the higher Witt groups of a finite field of
characteristic 2 are all isomorphic to Z/2. They generalize in some sense the
Dickson and Arf invariants.


title: On von Neumann and Bell theorems applied to quantumness tests

abstract:
  The issues, raised in arXiv:0809.011, concerning the relevance of the von
Neumann theorem for the single-system's quantumness test proposed in
arXiv:0704.1962 and performed for the case of single photon polarization in
arXiv:0804.1646, and the usefulness of Bell's inequality for testing the idea
of macroscopic quantum systems are discussed in some details. Finally, the
proper quantum mechanical description of the experiment with polarized photon
beams is presented.


title:
The hyperfine energy levels of alkali metal dimers: ground-state
  homonuclear molecules in magnetic fields

abstract:
  We investigate the hyperfine energy levels and Zeeman splittings for
homonuclear alkali-metal dimers in low-lying rotational and vibrational states,
which are important for experiments designed to produce quantum gases of deeply
bound molecules. We carry out density-functional theory (DFT) calculations of
the nuclear hyperfine coupling constants. For nonrotating states, the
zero-field splittings are determined almost entirely by the scalar nuclear
spin-spin coupling constant. By contrast with the heteronuclear case, the total
nuclear spin remains a good quantum number in a magnetic field. We also
investigate levels with rotational quantum number N = 1, which have long-range
anisotropic quadrupole-quadrupole interactions and may be collisionally stable.
For these states the splitting is dominated by nuclear quadrupole coupling for
most of the alkali-metal dimers and the Zeeman splittings are considerably more
complicated.


title: Ultra High Energy Cosmic Rays from earth-based observatories

abstract:
  In this paper, prepared for the Physics in Collisions 2008 Conference, the
most recent results on UHECRs from earth-based observatories are exposed and
reviewed.


title: A topological chaos framework for hash functions

abstract:
  This paper presents a new procedure of generating hash functions which can be
evaluated using some mathematical tools. This procedure is based on discrete
chaotic iterations.
  First, it is mathematically proven, that these discrete chaotic iterations
can be considered as a \linebreak particular case of topological chaos. Then,
the process of generating hash function based on the \linebreak topological
chaos is detailed. Finally it is shown how some tools coming from the domain of
\linebreak topological chaos can be used to measure quantitatively and
qualitatively some desirable properties for hash functions. An illustration
example is detailed in order to show how one can create hash functions using
our theoretical study.
  Key-words : Discrete chaotic iterations. Topological chaos. Hash function


title:
Discovery of a very high energy gamma-ray signal from the 3C 66A/B
  region

abstract:
  The MAGIC telescope observed the region around the distant blazar 3C 66A for
54.2 h in 2007 August-December. The observations resulted in the discovery of a
gamma-ray source at energies above 150 GeV centered at celestial coordinates
RA=2h23m12s and DEC=43deg0.7' (MAGIC J0223+430), coinciding with the nearby
radio galaxy 3C 66B. A possible association of the excess with the blazar 3C
66A is discussed. The energy spectrum of MAGIC J0223+430 follows a power law
with a normalization of (1.7+-0.3_(stat)+-0.6_(syst)) 10^(-11)
TeV^(-1)cm^(-2)s^(-1) at 300 GeV and a photon index
Gamma=-3.10+-0.31_(stat)+-0.2_(syst). No significant variability of the signal
was found during the observation period.


title: A watermarking algorithm satisfying topological chaos properties

abstract:
  A new watermarking algorithm is given, it is based on the so-called chaotic
iterations and on the choice of some coefficients which are deduced from the
description of the carrier medium. After defining these coefficients, chaotic
discrete iterations are used to encrypt the watermark and to embed it in the
carrier medium. This procedure generates a topological chaos and ensures that
the required properties of a watermarking algorithm are satisfied.
  Key-words: Watermarking, Encryption, Chaotic iterations, Topological chaos,
Information hiding


title: Kinematics of AGN Jets

abstract:
  The fine-scale structure and the kinematics of relativistic active galactic
nuclei (AGN) jets have been studied by very-long-baseline interferometry at
very high resolutions since 1998 at 2 cm wavelength for a sample of over a
hundred radio sources (VLBA 2cm Survey and MOJAVE programs). Since 2007, this
is being complemented by the TANAMI project, based on southern observations
with the Australian LBA at 3.6 cm and 1.1 cm wavelengths. From our observation
campaign, we find that most of the radio jets show linear morphologies at
parsec-scales, but some of show curvature and non-radial motions. Features are
observed to move at highly relativistic speeds, with Lorentz factors extending
above values of 30. We also provide a brief description of the relationship of
our radio findings with the AGN observations by the new Fermi Gamma-ray Space
Telescope.


title: Dynamic equilibrium Mechanism for Surface Nanobubble Stabilization

abstract:
  Recent experiments have convincingly demonstrated the existence of surface
nanobubbles on submerged hydrophobic surfaces. However, classical theory
dictates that small gaseous bubbles quickly dissolve because their large
Laplace pressure causes a diffusive outflux of gas. Here we suggest that the
bubbles are stabilized by a continuous influx of gas near the contact line, due
to the gas attraction towards hydrophobic walls (Dammer & Lohse, PRL96, 206101
(2006); Zhang {\it et al.}, PRL98, 136101 (2007); Mezger {\it et al.}, J.\
Chem. Phys. 128, 244705 (2008)). This influx balances the outflux and allows
for a meta-stable equilibrium, which however vanishes in thermodynamic
equilibrium. Our theory predicts the equilibrium radius of the surface
nanobubbles, as well as the threshold for surface nanobubble formation as a
function of hydrophobicity and gas concentration.


title: Elliptic equations in divergence form with partially BMO coefficients

abstract:
  The solvability in Sobolev spaces is proved for divergence form second order
elliptic equations in the whole space, a half space, and a bounded Lipschitz
domain. For equations in the whole space or a half space, the leading
coefficients $a^{ij}$ are assumed to be measurable in one direction and have
small BMO semi-norms in the other directions. For equations in a bounded
domain, additionally we assume that $a^{ij}$ have small BMO semi-norms in a
neighborhood of the boundary of the domain. We give a unified approach of both
the Dirichlet boundary problem and the conormal derivative problem. We also
investigate elliptic equations in Sobolev spaces with mixed norms under the
same assumptions on the coefficients.


title: Powering the Jets in NGC1052

abstract:
  We have studied the inner regions of the LINER galaxy NGC1052 since the mid
1990s at high resolution with 15 GHz very-long-baseline interferometry
observations. A compact, two-sided jet structure is revealed, with multiple
sub-parsec scale features moving outward from the central region with typical
speeds of 0.26 c. Complementary to this, since early 2005 we are performing a
multi-mission campaign of observations of this source, including X-ray
spectroscopy, X-ray, and radio flux density monitoring, and VLBA observations
at 22 GHz and 43 GHz. X-ray variability is present at time scales of weeks,
comparable with the structural changes observed by VLBI. Here we present first
results of the high-resolution imaging observations and discuss these findings
in the context of the multi-band campaign.


title: CLAS12 and its initial Science Program at the Jefferson Lab Upgrade

abstract:
  An overview of the CLAS12 detector is presented and the initial physics
program after the energy-doubling of the Jefferson Lab electron accelerator.
Construction of the 12 GeV upgrade project has started October 2008. A broad
program has been developed to map the nucleon's 3-dimensional spin and flavor
content through the measurement of deeply exclusive and semi-inclusive
processes. Other programs include forward distribution function to large $x_{B}
\le 0.85$ and of the quark and gluon polarized distribution functions, as well
as nucleon ground state and transition form factors at high $Q^2$. The 12 GeV
electron beam and the large acceptance of CLAS12 are also well suited to
explore hadronization properties using the nucleus as a laboratory


title:
Bulk induced boundary perturbations for N=1 superconformal field
  theories

abstract:
  The N=1 superconformal circle theory consisting of a free boson and a free
fermion is considered. At any radius the theory has standard Dirichlet and
Neumann branes, but for rational radii there are additional superconformal
boundary conditions that are labelled by elements in a quotient of SU(2). We
analyse how these branes behave under the radius-changing bulk perturbation. As
in the bosonic case, the bulk perturbation induces in general a boundary RG
flow whose end-point is a superposition of Dirichlet or Neumann branes.


title:
Temperature dependence of the superheating field for superconductors in
  the high-k London limit

abstract:
  We study the metastability of the superheated Meissner state in type II
superconductors with k >> 1 beyond Ginzburg-Landau theory, which is applicable
only in the vicinity of the critical temperature. Within Eilenberger's
semiclassical approximation, we use the local electrodynamic response of the
superconductor to derive a generalized thermodynamic potential valid at any
temperature. The stability analysis of this functional yields the temperature
dependence of the superheating field. Finally, we comment on the implications
of our results for superconducting cavities in particle accelerators.


title: Computation of the response functions of spiral waves in active media

abstract:
  Rotating spiral waves are a form of self-organization observed in spatially
extended systems of physical, chemical, and biological nature. A small
perturbation causes gradual change in spatial location of spiral's rotation
center and frequency, i.e. drift. The response functions (RFs) of a spiral wave
are the eigenfunctions of the adjoint linearized operator corresponding to the
critical eigenvalues $\lambda = 0, \pm i\omega$. The RFs describe the spiral's
sensitivity to small perturbations in the way that a spiral is insensitive to
small perturbations where its RFs are close to zero. The velocity of a spiral's
drift is proportional to the convolution of RFs with the perturbation. Here we
develop a regular and generic method of computing the RFs of stationary
rotating spirals in reaction-diffusion equations. We demonstrate the method on
the FitzHugh-Nagumo system and also show convergence of the method with respect
to the computational parameters, i.e. discretization steps and size of the
medium. The obtained RFs are localized at the spiral's core.


title: A Classical Analysis of Capacitively Coupled Superconducting Qubits

abstract:
  An electrical circuit consisting of two capacitively coupled inductive loops,
each interrupted by a Josephson junction, is analyzed through the classical
RSCJ model. The same circuit has recently been studied experimentally and the
results were used to demonstrate quantum mechanical entanglement in the system
by observing the correlated states of the two inductive loops after initial
microwave perturbations. Our classical analysis shows that the observed
phenomenon exists entirely within the classical RSCJ model, and we provide a
detailed intuitive description of the transient dynamics responsible for the
observations.


title: The TRB for HADES and FAIR experiments at GSI

abstract:
  The TRB hardware module is a multi-purpose Trigger and Readout Board with
on-board DAQ functionality developed for the upgrade of the HADES experiment.
It contains a single computer chip (Etrax) running Linux as a well as a 100
Mbit/s Ethernet interface. It has been orginally designed to work as a
128-channel Time to Digital Converter based on the HPTDC chip from CERN. The
new version contains a 2 Gbit/s optical link and an interface connector (15
Gbit/s) in order to realize an add-on card concept which makes the hardware
very flexible. Moreover, an FPGA chip (Xilinx, Virtex 4 LX 40) and a TigerSharc
DSP provide new computing resources which can be used to run on-line analysis
algorithms. The TRB is proposed as a prototype for new modules for the planned
detector systems PANDA and CBM at the future FAIR facility at GSI-Darmstadt.


title: Studying the emergence of invasiveness in tumours using game theory

abstract:
  Tumour cells have to acquire a number of capabilities if a neoplasm is to
become a cancer. One of these key capabilities is increased motility which is
needed for invasion of other tissues and metastasis. This paper presents a
qualitative mathematical model based on game theory and computer simulations
using cellular automata. With this model we study the circumstances under which
mutations that confer increased motility to cells can spread through a tumour
made of rapidly proliferating cells. The analysis suggests therapies that could
help prevent the progression towards malignancy and invasiveness of benign
tumours.


title: The Transit Light Curve Project. X. A Christmas Transit of HD 17156b

abstract:
  Photometry is presented of the Dec. 25, 2007 transit of HD 17156b, which has
the longest orbital period and highest orbital eccentricity of all the known
transiting exoplanets. New measurements of the stellar radial velocity are also
presented. All the data are combined and integrated with stellar-evolutionary
modeling to derive refined system parameters. The planet's mass and radius are
found to be 3.212_{-0.082}^{+0.069} Jupiter masses and 1.023_{-0.055}^{+0.070}
Jupiter radii. The corresponding stellar properties are 1.263_{-0.047}^{+0.035}
solar masses and 1.446_{-0.067}^{+0.099} solar radii. The planet is smaller by
1 sigma than a theoretical solar-composition gas giant with the same mass and
equilibrium temperature, a possible indication of heavy-element enrichment. The
midtransit time is measured to within 1 min, and shows no deviation from a
linear ephemeris (and therefore no evidence for orbital perturbations from
other planets). We provide ephemerides for future transits and superior
conjunctions. There is an 18% chance that the orbital plane is oriented close
enough to edge-on for secondary eclipses to occur at superior conjunction.
Observations of secondary eclipses would reveal the thermal emission spectrum
of a planet that experiences unusually large tidal heating and insolation
variations.


title:
Averages of central L-values of Hilbert modular forms with an
  application to subconvexity

abstract:
  We use the relative trace formula to obtain exact formulas for central values
of certain twisted quadratic base change L-functions averaged over Hilbert
modular forms of a fixed weight and level. We apply these formulas to the
subconvexity problem for these L-functions. We also establish an
equidistribution result for the Hecke eigenvalues weighted by these L-values.


title: Robust Estimation of Mean Values

abstract:
  In this paper, we develop a computational approach for estimating the mean
value of a quantity in the presence of uncertainty. We demonstrate that, under
some mild assumptions, the upper and lower bounds of the mean value are
efficiently computable via a sample reuse technique, of which the computational
complexity is shown to posses a Poisson distribution.


title: Geometric entropy of geodesic currents on free groups

abstract:
  A \emph{geodesic current} on a free group $F$ is an $F$-invariant measure on
the set $\partial^2 F$ of pairs of distinct points of $\partial F$. The space
of geodesic currents on $F$ is a natural companion of Culler-Vogtmann's Outer
space $cv(F)$ and studying them together yields new information about both
spaces as well as about the group $Out(F)$. The main aim of this paper is to
introduce and study the notion of {\it geometric entropy} $h_T(\mu)$ of a
geodesic current $\mu$ with respect to a point $T$ of $cv(F)$, which can be
viewed as a length function on $F$. The geometric entropy is defined as the
slowest rate of exponential decay of $\mu$-measures of bi-infinite cylinders in
$F$, as the $T$-length of the word defining such a cylinder goes to infinity.
We obtain an explicit formula for $h_{T'}(\mu_T)$, where $T,T'$ are arbitrary
points in $cv(F)$ and where $\mu_T$ denotes a Patterson-Sullivan current
corresponding to $T$. It involves the volume entropy $h(T)$ and the extremal
distortion of distances in $T$ with respect to distances in $T'$. It follows
that, given $T$ in the projectivized outer space $CV(F)$, $h_{T'}(\mu_T)$ as
function of $T'\in CV(F)$ achieves a strict global maximum at $T'=T$. We also
show that for any $T\in cv(F)$ and any geodesic current $\mu$ on $F$,
$h_T(\mu)\le h(T)$, where the equality is realized when $\mu=\mu_T$. For points
$T\in cv(F)$ with simplicial metric (where all edges have length one), we
relate the geometric entropy of a current and the measure-theoretic entropy.


title: Introduction to Quantum Noise, Measurement and Amplification

abstract:
  The topic of quantum noise has become extremely timely due to the rise of
quantum information physics and the resulting interchange of ideas between the
condensed matter and AMO/quantum optics communities. This review gives a
pedagogical introduction to the physics of quantum noise and its connections to
quantum measurement and quantum amplification. After introducing quantum noise
spectra and methods for their detection, we describe the basics of weak
continuous measurements. Particular attention is given to treating the standard
quantum limit on linear amplifiers and position detectors using a general
linear-response framework. We show how this approach relates to the standard
Haus-Caves quantum limit for a bosonic amplifier known in quantum optics, and
illustrate its application for the case of electrical circuits, including
mesoscopic detectors and resonant cavity detectors.


title: Cosmic Constraint on Ricci Dark Energy Model

abstract:
  In this paper, a holographic dark energy model, dubbed Ricci dark energy, is
confronted with cosmological observational data from type Ia supernovae (SN
Ia), baryon acoustic oscillations (BAO) and cosmic microwave background (CMB).
By using maximum likelihood method, it is found out that Ricci dark energy
model is a viable candidate of dark energy model with the best fit parameters:
$\Omega_{m0}=0.34\pm 0.04$, $\alpha=0.38\pm 0.03$ with $1\sigma$ error. Here,
$\alpha$ is a dimensionless parameter related with Ricci dark energy $\rho_{R}$
and Ricci scalar $R$, i.e., $\rho_{R}\propto \alpha R$.


title:
Investigation of resonant and transient phenomena in Josephson junction
  flux qubits

abstract:
  We present an analytical and computational study of resonances and transient
responses in a classical Josephson junction system. A theoretical basis for
resonances in a superconducting loop with three junctions is presented,
outlining both the direct relationship between the dynamics of single- and
multi-junction systems, and the direct relationships between observations of
the classical counterparts to Rabi oscillations, Ramsey fringes, and spin echo
oscillations in this class of systems. We show simulations data along with
analytical analyses of the classical model, and the results are related to
previously reported experiments conducted on three junction loops. We further
investigate the effect of off-resonant microwave perturbations to, e.g., the
Rabi-type response of the Josephson system, and we relate this response back to
the nonlinear and multi-valued resonance behavior previously reported for a
single Josephson junction. The close relationships between single and
multi-junction behavior demonstrates the underlying dynamical mechanism for a
whole class of classical counterparts to expected quantum mechanical
observations in a variety of systems; namely the resonant and transient
behavior of a particle in an anharmonic potential well with subsequent escape.


title:
Evolutionary game theory elucidates the role of glycolysis in glioma
  progression and invasion

abstract:
  Tumour progression has been described as a sequence of traits or phenotypes
that cells have to acquire if the neoplasm is to become an invasive and
malignant cancer. Although the genetic mutations that lead to these phenotypes
are random, the process by which some of these mutations become successful and
spread is influenced by the tumour microenvironment and the presence of other
phenotypes. It is thus likely that some phenotypes that are essential in tumour
progression will emerge in the tumour population only with the prior presence
of other different phenotypes. In this paper we use evolutionary game theory to
analyse the interactions between three different tumour cell phenotypes defined
by autonomous growth, anaerobic glycolysis, and cancer cell invasion. The model
allows to understand certain specific aspects of glioma progression such as the
emergence of diffuse tumour cell invasion in low-grade tumours. We find that
the invasive phenotype is more likely to evolve after the appearance of the
glycolytic phenotype which would explain the ubiquitous presence of invasive
growth in malignant tumours. The result suggests that therapies which increase
the fitness cost of switching to anaerobic glycolysis might decrease the
probability of the emergence of more invasive phenotypes


title:
Analytic subordination results in free probability from
  non-coassociative derivation-comultiplications

abstract:
  We extend Voiculescu's approach to analytic subordination through the
coalgebra of the free difference quotient to non-coassociative
derivation-comultiplications appearing in free probability theory. We obtain
new proofs of Voiculescu's analytic subordination results for freely Markovian
triples, and for multiplication of unitaries which are free with amalgamation.


title: Quasi-unit cell description of two-dimensional octagonal quasilattice

abstract:
  We present a cluster covering scheme to construct the two-dimensional
octagonal quasilattice. A quasi-unit cell is successfully found which is a
two-color cluster similar to the Gummelt's two-color decagon in five-fold
quasilattice. The quasi-unit cells overlap each other following certain
covering rules and thus lead to a perfect octagonal quasilattice.


title: High-velocity collision of two black holes

abstract:
  We study nonaxisymmetric collision of two black holes (BHs) with a high
velocity $v=|dx^i/dx^0|=0.6$--$0.9c$ at infinity, where $x^{\mu}$ denotes
four-dimensional coordinates. We prepare two boosted BHs for the initial
condition which is different from that computed by a simple moving-puncture
approach. By extrapolation of the numerical results, we find that the impact
parameter has to be smaller that $\approx 2.5GM_0/c^2$ for formation of a BH in
the collision for $v \to c$, where $M_0 c^2$ is the initial total ADM mass
energy of the system. For the critical value of the impact parameter, 20--30%
of mass energy and 60--70% of angular momentum are dissipated by gravitational
radiation for $v=0.6$--$0.9c$.


title: Radiative Upsilon decays and a light pseudoscalar Higgs in the NMSSM

abstract:
  We study possible effects of a light CP-odd Higgs boson on radiative Upsilon
decays in the Next-to-Minimal Supersymmetric Standard Model. Recent constraints
from CLEO on radiative Upsilon(1S) decays are translated into constraints on
the parameter space of CP-odd Higgs boson masses and couplings, and compared to
constraints from B physics and the muon anomalous magnetic moment. Possible
Higgs - eta_b(nS) mixing effects are discussed, notably in the light of the
recent measurement of the eta_b(1S) mass by Babar: The somewhat large
Upsilon(1S) - eta_b(1S) hyperfine splitting could easily be explained by the
presence of a CP-odd Higgs boson with a mass in the range 9.4 - 10.5 GeV. Then,
tests of lepton universality in inclusive radiative Upsilon decays can provide
a visible signal in forthcoming experimental data.


title:
Efficient Parallel Algorithm for Statistical Ion Track Simulations in
  Crystalline Materials

abstract:
  We present an efficient parallel algorithm for statistical Molecular Dynamics
simulations of ion tracks in solids. The method is based on the Rare Event
Enhanced Domain following Molecular Dynamics (REED-MD) algorithm, which has
been successfully applied to studies of, e.g., ion implantation into
crystalline semiconductor wafers. We discuss the strategies for parallelizing
the method, and we settle on a host-client type polling scheme in which a
multiple of asynchronous processors are continuously fed to the host, which, in
turn, distributes the resulting feed-back information to the clients. This
real-time feed-back consists of, e.g., cumulative damage information or
statistics updates necessary for the cloning in the rare event algorithm. We
finally demonstrate the algorithm for radiation effects in a nuclear oxide
fuel, and we show the balanced parallel approach with high parallel efficiency
in multiple processor configurations.


title: A Game Theoretical Perspective on the Somatic Evolution of Cancer

abstract:
  Environmental and genetic mutations can transform the cells in a co-operating
healthy tissue into an ecosystem of individualistic tumour cells that compete
for space and resources. Various selection forces are responsible for driving
the evolution of cells in a tumour towards more malignant and aggressive
phenotypes that tend to have a fitness advantage over the older populations.
Although the evolutionary nature of cancer has been recognised for more than
three decades (ever since the seminal work of Nowell) it has been only recently
that tools traditionally used by ecological and evolutionary researchers have
been adopted to study the evolution of cancer phenotypes in populations of
individuals capable of co-operation and competition. In this chapter we will
describe game theory as an important tool to study the emergence of cell
phenotypes in a tumour and will critically review some of its applications in
cancer research. These applications demonstrate that game theory can be used to
understand the dynamics of somatic cancer evolution and suggest new therapies
in which this knowledge could be applied to gain some control over the
evolution of the tumour.


title: Head-Tail Galaxies: Beacons of High-Density Regions in Clusters

abstract:
  Using radio data at 1.4 GHz from the ATCA we identify five head-tail (HT)
galaxies in the central region of the Horologium-Reticulum Supercluster (HRS).
Physical parameters of the HT galaxies were determined along with substructure
in the HRS to probe the relationship between environment and radio properties.
Using a density enhancement technique applied to 582 spectroscopic measurements
in the 2 degree x 2 degree region about A3125/A3128, we find all five HT
galaxies reside in regions of extremely high density (>100 galaxies/Mpc^3). In
fact, the environments surrounding HT galaxies are statistically denser than
those environments surrounding non-HT galaxies and among the densest
environments in a cluster. Additionally, the HT galaxies are found in regions
of enhanced X-ray emission and we show that the enhanced density continues out
to substructure groups of 10 members. We propose that it is the high densities
that allow ram pressure to bend the HT galaxies as opposed to previously
proposed mechanisms relying on exceptionally high peculiar velocities.


title: Ray Class Groups of Quadratic and Cyclotomic Fields

abstract:
  This paper studies Galois extensions over real quadratic number fields or
cyclotomic number fields ramified only at one prime. In both cases, the ray
class groups are computed, and they give restrictions on the finite groups that
can occur as such Galois groups. Also the explicit structure of ray class
groups of regular cyclotomic number field is given.


title: On the Capacity and Generalized Degrees of Freedom of the X Channel

abstract:
  We explore the capacity and generalized degrees of freedom of the two-user
Gaussian X channel, i.e. a generalization of the 2 user interference channel
where there is an independent message from each transmitter to each receiver.
There are three main results in this paper. First, we characterize the sum
capacity of the deterministic X channel model under a symmetric setting.
Second, we characterize the generalized degrees of freedom of the Gaussian X
channel under a similar symmetric model. Third, we extend the noisy
interference capacity characterization previously obtained for the interference
channel to the X channel. Specifically, we show that the X channel associated
with noisy (very weak) interference channel has the same sum capacity as the
noisy interference channel.


title:
Equation of state at finite density in two-flavor QCD with improved
  Wilson quarks

abstract:
  We study the equation of state in two-flavor QCD at finite temperature and
density. Simulations are made with the RG-improved gluon action and the
clover-improved Wilson quark action. Along the lines of constant physics for
$m_{\rm PS}/m_{\rm V} = 0.65$ and 0.80, we compute the derivatives of the quark
determinant with respect to the quark chemical potential $\mu_q$ up to the
fourth order at $\mu_q=0$. We adopt several improvement techniques in the
evaluation. We study thermodynamic quantities and quark number susceptibilities
at finite $\mu_q$ using these derivatives. We find enhancement of the quark
number susceptibility at finite $\mu_q$, in accordance with previous
observations using staggered-type quarks. This suggests the existence of a
nearby critical point.


title: Achievement of Alternative Configurations of Vehicles on Multiple Lanes

abstract:
  Heavy traffic congestion daily occurs at merging sections on highway. For
releasing this congestion, possibility of alternative configuration of vehicles
on multiple-lane road is discussed in this paper. This is the configuration
where no vehicles move aside on the other lane. It has a merit in making smooth
merging at an intersection or a junction due to so-called the "zipper effect".
We show, by developing a cellular automaton model for multiple lanes, that this
configuration is achieved by simple local interactions between vehicles
neighboring each other. The degree of the alternative configuration in terms of
the spatial increase of parallel driving length is studied by using both
numerical simulations and mean field theory. We successfully construct a
theoretical method for calculating this degree of the alternative configuration
by using cluster approximation. It is shown that the theoretical results
coincide with those of the simulations very well.


title: Macroscopic signature of protected spins in a dense frustrated magnet

abstract:
  The inability of systems of interacting objects to satisfy all constraints
simultaneously leads to frustration. A particularly important consequence of
frustration is the ability to access certain protected parts of a system
without disturbing the others. For magnets such "protectorates" have been
inferred from theory and from neutron scattering, but their practical
consequences have been unclear. We show that a magnetic analogue of optical
hole-burning can address these protected spin clusters in a well-known,
geometrically frustrated Heisenberg system, gadolinium gallium garnet. Our
measurements additionally provide a resolution of a famous discrepancy between
the bulk magnetometry and neutron diffraction results for this magnetic
compound.


title: Creation and Reproduction of Model Cells with Semipermeable Membrane

abstract:
  A high activity of reactions can be confined in a model cell with a
semipermeable membrane in the Schl\"ogl model. It is interpreted as a model of
primitive metabolism in a cell. We study two generalized models to understand
the creation of primitive cell systems conceptually from the view point of the
nonlinear-nonequilibrium physics. In the first model, a single-cell system with
a highly active state confined by a semipermeable membrane is spontaneously
created from an inactive homogeneous state by a stochastic jump process. In the
second model, many cell structures are reproduced from a single cell, and a
multicellular system is created.


title:
Neutrino-less Double Beta Decay of 48Ca studied by CaF2(Eu)
  Scintillators

abstract:
  We searched for the neutrino-less double beta decay(0nbb) of 48Ca by using
CaF2(Eu) scintillators. Analysis of their pulse shapes was effective to reduce
backgrounds. No events are observed in the Q-value region for the data of 3394
kg days. It gives a lower limit (90% confidence level) of T > 2.7 x 10^22 year
for the half life of 0nbb of 48Ca. Combined with our previous data for 1553 kg
days, we obtained more stringent limit of T > 5.8 x 10^22 year.


title: Plasmonic Enhancement of Emission from Si-nanocrystals

abstract:
  Plasmonic gratings of different periodicities are fabricated on top of
Silicon nanocrystals embedded in Silicon Dioxide. Purcell enhancements of up to
2 were observed, which matches the value from simulations. Plasmonic
enhancements are observed for the first three orders of the plasmonic modes,
with the peak enhancement wavelength varying with the periodicity. Biharmonic
gratings are also fabricated to extract the enhanced emission from the first
order plasmonic mode, resulting in enhancements with quality factors of up to
16.


title:
q-Wakimoto Modules and Integral Formulae of the Quantum
  Knizhnik-Zamolodchikov Equations

abstract:
  Matrix elements of intertwining operators between $q$-Wakimoto modules
associated to the tensor product of representations of $U_q(\widehat{sl_2})$
with arbitrary spins are studied. It is shown that they coincide with the
Tarasov-Varchenko's formulae of the solutions of the qKZ equations. The result
generalizes that of the previous paper [Kuroki K., Nakayashiki A., SIGMA 4
(2008), 049, 13 pages, arXiv:0802.1776].


title: Image and Reciprocal Image of a Measure. Compatibility Theorem

abstract:
  It is proposed that to the usual probability theory, three definitions and a
new theorem are added, the resulting theory allows one to displace the central
role usually given to the notion of conditional probability. When a mapping
$\phi$ is defined between two measurable spaces, to each measure $\mu$
introduced on the first space, there corresponds an image $\phi[\mu]$ on the
second space, and, reciprocally, to each measure $\nu$ defined on the second
space the corresponds a reciprocal image $\phi^{-1}[\nu]$ on the first space.
As the intersection $\cap$ of two measures is easy to introduce, a relation
like $ \phi[ \mu \cap \phi^{-1} [\nu] ] = \phi[\mu] \cap \nu $ makes sense. It
is, indeed, a theorem of the theory. This theorem gives mathematical
consistency to inferences drawn from physical measurements.


title:
Finite Energy Monopoles in Non-Abelian Gauge Theories on Odd-dimensional
  Spaces

abstract:
  In higher dimensional gauge theory, we need energies with higher power terms
of field strength in order to realize point-wise monopoles. We consider new
models with higher power terms of field strength and extraordinary kinetic term
of scalar field. Monopole charges are computed as integrals over spheres and
they are related to mapping class degree. Hedge-Hog solutions are investigated
in these models. Every differential equation for these solutions is Abel's
differential equation. A condition for existence of finite energy solution is
shown. Spaces of 1-jets of these equations are defined as sets of zeros of
polynomials. Those spaces can be interpreted as singular quartic surfaces in
three-dimensional complex projective space.


title:
Measurement of the Forward-Backward Charge Asymmetry in Top-Quark Pair
  Production in Proton-Antiproton Collisions at D0

abstract:
  A measurement of the forward-backward charge asymmetry in top-antitop
(t\bar{t}) pair production in proton-antiproton (p\bar{p}) collisions is
presented. The asymmetry is measured for different jet multiplicities in the
lepton+jets final state on 0.9 fb^{-1} of data collected by the D0 experiment
at the Fermilab Tevatron Collider. The result is sensitive to new physics,
which is demonstrated by setting an upper limit on t\bar{t} production via
heavy neutral gauge bosons (Z^{\prime}).


title: Statistical Learning Theory: Models, Concepts, and Results

abstract:
  Statistical learning theory provides the theoretical basis for many of
today's machine learning algorithms. In this article we attempt to give a
gentle, non-technical overview over the key ideas and insights of statistical
learning theory. We target at a broad audience, not necessarily machine
learning researchers. This paper can serve as a starting point for people who
want to get an overview on the field before diving into technical details.


title: Alternating current driven instability in magnetic junctions

abstract:
  An effect is considered of alternating (high-frequency) current on the
spin-valve type magnetic junction configuration. The stability with respect to
small fluctuations is investigated in the macrospin approximation. When the
current frequency is close to the eigenfrequency (precession frequency) of the
free layer, parametric resonance occurs. Both collinear configurations,
antiparallel and parallel ones, can become unstable under resonance conditions.
The antiparallel configuration can become unstable under non-resonant
conditions, also. The threshold current density amplitude is of the order of
the dc current density switching the magnetic junction.


title: High-Mass Resonances Decaying to Leptons and Photons at the Tevatron

abstract:
  The high-mass spectrum of lepton and photon pairs is sensitive to a broad
range of new physics. Examples are extra dimensions and new gauge bosons such
as the W' and Z'. Additionally, electron compositeness would result in excited
electrons that decay into an electron and a photon. We report the latest
results of searches for high-mass dilepton, diphoton, and electron-photon
resonances by the CDF and D0 experiments at the Tevatron.


title:
A theoretical framework for the detection of point-sources in Cosmic
  Microwave Background maps

abstract:
  The detection of point-sources in microwave maps is a critical step in the
analysis of the Cosmic Microwave Background (CMB) data. If not properly
removed, these sources have adverse effects on the estimation of the
power-spectrum and/or the test of Gaussianity of the CMB component. The
techniques to extract point sources from an observed image used up to now do
not show a general consensus about their real performance and properties. Their
characteristics have been studied essentially through numerical simulations
based on semi-empirical models of the CMB and the Galactic foreground. Such
models often have different levels of sophistication and/or are based on
different physical assumptions (e.g. the number of Galactic components and
level of the noise). Moreover, the application of a given technique to a set of
data (either simulated or experimental) requires the tuning of one or more
parameters that unavoidably is a subjective operation. Hence, a reliable
comparison is difficult. What is missing is a statistical analysis of the
properties of the proposed methodologies. This is the aim of the present paper.
The statistical properties of the detection techniques in the context of two
different criteria, i.e. the Neyman-Pearson criterion and the maximization of
the signal-to-noise ratio, are analyzed through an analytical approach. Various
examples, techniques and the conditions under which they work satisfactorily
are shown together with their limits and implementation details. Exploiting
some a priori information, it is possible to develop simple algorithms with
performances similar to those of more sophisticated but complex techniques. In
this respect, a detection algorithm, useful in future ground-based experiments
as, for example the Atacama Large Millimeter/submillimeter Array, is presented.


title:
A Charlier-Parseval approach to Poisson approximation and its
  applications

abstract:
  A new approach to Poisson approximation is proposed. The basic idea is very
simple and based on properties of the Charlier polynomials and the Parseval
identity. Such an approach quickly leads to new effective bounds for several
Poisson approximation problems. A selected survey on diverse Poisson
approximation results is also given.


title: Almost $\cal D$-split sequences and derived equivalences

abstract:
  In this paper, we introduce almost $\cal D$-split sequences and establish an
elementary but somewhat surprising connection between derived equivalences and
Auslander-Reiten sequences via BB-tilting modules. In particular, we obtain
derived equivalences from Auslander-Reiten sequences (or $n$-almost split
sequences), and Auslander-Reiten triangles.


title: Regular strongly typical blocks of $\mathcal{O}^{\mathfrak{q}}$

abstract:
  We use the technique of Harish-Chandra bimodules to prove that regular
strongly typical blocks of the category $\mathcal{O}$ for the queer Lie
superalgebra $\mathfrak{q}_n$ are equivalent to the corresponding blocks of the
category $\mathcal{O}$ for the Lie algebra $\mathfrak{gl}_n$.


title:
The m-reduction in Conformal Field Theory as the Morita equivalence on
  two-tori

abstract:
  We study the Morita equivalence for field theories on noncommutative
two-tori. For rational values of the noncommutativity parameter $\theta $ (in
appropriate units) we show the equivalence between an abelian noncommutative
field theory and a nonabelian theory of twisted fields on ordinary space. We
concentrate on a particular conformal field theory (CFT), the one obtained by
means of the m-reduction procedure (V. Marotta, J. Phys. A 26 (1993) 3481; Mod.
Phys. Lett. A 13 (1998) 853; Nucl. Phys. B 527 (1998) 717), and show that the
Morita equivalence also holds at this level. An application to the physics of a
quantum Hall fluid at Jain fillings \nu =m/2pm+1 is explicitly considered in
order to further elucidate such a correspondence.


title: The BAST algorithm for transit detection

abstract:
  The pioneer space mission for photometric exoplanet searches, CoRoT, steadily
monitors about 12000 stars in each of its fields of view. Transit detection
algorithms are applied to derive promising planetary candidates, which are then
followed-up with ground-based observations. We present BAST (Berlin Automatic
Search for Transits), a new algorithm for periodic transit detection, and test
it on simulated CoRoT data. BAST searches for box-shaped signals in normalized,
filtered, variability-fitted, and unfolded light curves. A low-pass filter is
applied to remove high-frequency signals, and linear fits to subsections of
data are subtracted to remove the star's variability. A search for periodicity
is then performed in transit events identified above a given detection
threshold. Some criteria are defined to better separate planet candidates from
binary stars.
  From the analysis of simulated CoRoT light curves, we show that the BAST
detection performance is similar to that of the Box-fitting Least-Square (BLS)
method if the signal-to-noise ratio is high. However, the BAST box search for
transits computes 10 times faster than the BLS method. By adding periodic
transits to simulated CoRoT data, we show that the minimum periodic depth
detectable with BAST is a linearly increasing function of the noise level. For
low-noise light curves, the detection limit corresponds to a transit depth
d~0.01%, i.e. a planet of 1 Earth radius around a solar-type star.


title: Derived equivalences and stable equivalences of Morita type, I

abstract:
  For self-injective algebras, Rickard proved that each derived equivalence
induces a stable equivalence of Morita type. For general algebras, it is
unknown when a derived equivalence implies a stable equivalence of Morita type.
In this paper, we first show that each derived equivalence $F$ between the
derived categories of Artin algebras $A$ and $B$ arises naturally a functor
$\bar{F}$ between their stable module categories, which can be used to compare
certain homological dimensions of $A$ with that of $B$; and then we give a
sufficient condition for the functor $\bar{F}$ to be an equivalence. Moreover,
if we work with finite-dimensional algebras over a field, then the sufficient
condition guarantees the existence of a stable equivalence of Morita type. In
this way, we extend the classic result of Rickard. Furthermore, we provide
several inductive methods for constructing those derived equivalences that
induce stable equivalences of Morita type. It turns out that we may produce a
lot of (usually not self-injective) finite-dimensional algebras which are both
derived-equivalent and stably equivalent of Morita type, thus they share many
common invariants.


title: Physics of the ALICE experiment at the LHC

abstract:
  Some physical aspects of the ALICE experiment at the LHC are considered with
emphasis on possible probes of quark-gluon plasma, created in ultrarelativistic
heavy ion collisions.


title: Gapless Dirac Spectrum at High Temperature

abstract:
  Using the overlap Dirac operator I show that, contrary to some expectations,
even well above the critical temperature there is not necessarily a gap in the
Dirac spectrum in pure SU(2) gauge theory. This happens when the Polyakov loop
and the fermion boundary condition combine to give close to periodic boundary
condition for the fermions in the time direction. In this Polyakov loop sector
there is a non-vanishing density of Dirac eigenvalues around zero which implies
that chiral symmetry is spontaneously broken. I demonstrate this both directly
and also by finding good agreement with the random matrix theory prediction for
the distribution of the lowest Dirac eigenvalue. I show that the chiral
condensate increases with the temperature therefore it is very unlikely to be
explained by topological fluctuations that become rapidly smaller above T_c.
Finally I show that it is only a small fraction of the lowest Dirac eigenvalues
that decide which Polyakov loop sector is favored by the fermion determinant if
dynamical fermions are turned on. This provides a qualitative understanding of
how the loss of confinement above T_c implies the restoration of chiral
symmetry.


title: Limits of bifractional Brownian noises

abstract:
  Let $B^{H,K}=(B^{H,K}_{t}, t\geq 0)$ be a bifractional Brownian motion with
two parameters $H\in (0,1)$ and $K\in(0,1]$. The main result of this paper is
that the increment process generated by the bifractional Brownian motion
$(B^{H,K}_{h+t} -B^{H,K}_{h}, t\geq 0)$ converges when $h\to \infty$ to
$(2^{(1-K)/{2}}B^{HK}_{t}, t\geq 0)$, where $(B^{HK}_{t}, t\geq 0)$ is the
fractional Brownian motion with Hurst index $HK$. We also study the behavior of
the noise associated to the bifractional Brownian motion and limit theorems to
$B^{H,K}$.


title:
Energy resolution and discretization artefacts in the numerical
  renormalization group

abstract:
  We study the limits of the energy resolution that can be achieved in the
calculations of spectral functions of quantum impurity models using the
numerical renormalization group (NRG) technique with interleaving
(z-averaging). We show that overbroadening errors can be largely eliminated,
that higher-moment spectral sum rules are satisfied to a good accuracy, and
that positions, heights and widths of spectral features are well reproduced;
the NRG approximates very well the spectral-weight distribution. We find,
however, that the discretization of the conduction-band continuum nevertheless
introduces artefacts. We present a new discretization scheme which removes the
band-edge discretization artefacts of the conventional approach and
significantly improves the convergence to the continuum (Lambda -> 1) limit.
Sample calculations of spectral functions with high energy resolution are
presented. We follow in detail the emergence of the Kondo resonance in the
Anderson impurity model as the electron-electron repulsion is increased, and
the emergence of the phononic side peaks and the transition from the spin Kondo
effect to the charge Kondo effect in the Anderson-Holstein impurity model as
the electron-phonon coupling is increased. We also compute the spectral
function of the Hubbard model within the dynamical mean-field theory (DMFT),
confirming the presence of fine structure in the Hubbard bands.


title: Solutions of Navier Equations and Their Representation Structure

abstract:
  Navier equations are used to describe the deformation of a homogeneous,
isotropic and linear elastic medium in the absence of body forces.
Mathematically, the system is a natural vector (field) $O(n,\mbb{R})$-invariant
generalization of the classical Laplace equation, which physically describes
the vibration of a string. In this paper, we decompose the space of polynomial
solutions of Navier equations into a direct sum of irreducible
$O(n,\mbb{R})$-submodules and construct an explicit basis for each irreducible
summand. Moreover, we explicitly solve the initial value problems for Navier
equations and their wave-type extension--Lam\'e equations by Fourier expansion
and Xu's method of solving flag partial differential equations.

categories: math-ph astro-ph math.AP math.MP math.QA math.RT


title:
Relation between hyperbolic Nizhnik-Novikov-Veselov equation and
  stationary Davey-Stewartson II equation

abstract:
  A Lax system in three variables is presented, two equations of which form the
Lax pair of the stationary Davey-Stewartson II equation. With certain nonlinear
constraints, the full integrability condition of this Lax system contains the
hyperbolic Nizhnik-Novikov-Veselov equation and its standard Lax pair. The
Darboux transformation for the Davey-Stewartson II equation is used to solve
the hyperbolic Nizhnik-Novikov-Veselov equation. Using Darboux transformation,
global $n$-soliton solutions are obtained. It is proved that each $n$-soliton
solution approaches zero uniformly and exponentially at spatial infinity and is
asymptotic to $n^2$ lumps of peaks at temporal infinity.


title: Dirac electrons in graphene-based quantum wires and quantum dots

abstract:
  In this paper we analyse the electronic properties of Dirac electrons in
finite-size ribbons and in circular and hexagonal quantum dots made of
graphene.


title: The spatial clustering of X-ray selected AGN in the XMM-COSMOS field

abstract:
  We study the spatial clustering of 538 X-ray selected AGN in the 2 deg^2
XMM-COSMOS field that are spectroscopically identified to I_{AB}<23 and span
the redshift range z=0.2-3.0. The median redshift and luminosity of the sample
are z = 0.98 and L_{0.5-10}=6.3 x 10^{43} erg/s, respectively. A strong
clustering signal is detected at ~18sigma level, which is the most significant
measurement obtained to date for clustering of X-ray selected AGN. By fitting
the projected correlation function w(r_p) with a power law on scales of
r_p=0.3-40 Mpc/h, we derive a best fit comoving correlation length of r_0 = 8.6
+- 0.5 Mpc/h and slope of gamma=1.88 +- 0.07 (Poissonian errors; bootstrap
errors are about a factor of 2 larger). An excess signal is observed in the
range r_p~5-15 Mpc/h, which is due to a large scale structure at z ~ 0.36
containing about 40 AGN. When removing the z ~ 0.36 structure, or computing
w(r_p) in a narrower range around the peak of the redshift distribution (e.g.
z=0.4-1.6), the correlation length decreases to r_0 ~ 5-6 Mpc/h, which is
consistent with that observed for bright optical QSOs at the same redshift.
  We investigate the clustering properties of obscured and unobscured AGN
separately. Within the statistical uncertainties, we do not find evidence that
AGN with broad optical lines (BLAGN) cluster differently from AGN without broad
optical lines (non-BLAGN).
  The correlation length measured for XMM-COSMOS AGN at z~1 is similar to that
of massive galaxies (stellar mass M_*> 3 x 10^{10} M_sun) at the same redshift.
This suggests that AGN at z~1 are preferentially hosted by massive galaxies, as
observed both in the local and in the distant (z~2) Universe. (shortened)


title:
Enhancement of the Spin Accumulation at the Interface Between a
  Spin-Polarized Tunnel Junction and a Semiconductor

abstract:
  We report on spin injection experiments at a Co/Al$_2$O$_3$/GaAs interface
with electrical detection. The application of a transverse magnetic field
induces a large voltage drop $\Delta V$ at the interface as high as 1.2mV for a
current density of 0.34 nA.$\mu m^{-2}$. This represents a dramatic increase of
the spin accumulation signal, well above the theoretical predictions for spin
injection through a ferromagnet/semiconductor interface. Such an enhancement is
consistent with a sequential tunneling process via localized states located in
the vicinity of the Al$_2$O$_3$/GaAs interface. For spin-polarized carriers
these states act as an accumulation layer where the spin lifetime is large. A
model taking into account the spin lifetime and the escape tunneling time for
carriers travelling back into the ferromagnetic contact reproduces accurately
the experimental results.


title:
Temperature dependence of normal mode reconstructions of protein
  dynamics

abstract:
  Normal mode analysis is a widely used technique for reconstructing
conformational changes of proteins from the knowledge of native structures. In
this Letter, we investigate to what extent normal modes capture the salient
features of the dynamics over a range of temperatures from close to T = 0 to
above unfolding. We show that on the one hand, the use of normal modes at
physiological temperatures is justified provided proteins are cooperative. On
the other hand, it is imperative to consider several modes in order to
eliminate the unpredictable temperature dependence of single- mode
contributions to the protein fluctuations.


title: Pairing in fermionic systems: A quantum information perspective

abstract:
  The notion of "paired" fermions is central to important condensed matter
phenomena such as superconductivity and superfluidity. While the concept is
widely used and its physical meaning is clear there exists no systematic and
mathematical theory of pairing which would allow to unambiguously characterize
and systematically detect paired states. We propose a definition of pairing and
develop methods for its detection and quantification applicable to current
experimental setups. Pairing is shown to be a quantum correlation different
from entanglement, giving further understanding in the structure of highly
correlated quantum systems. In addition, we will show the resource character of
paired states for precision metrology, proving that the BCS states allow phase
measurements at the Heisenberg limit.


title:
Revisiting the optical depth of spiral galaxies using the Tully-Fisher B
  relation

abstract:
  Aims. We attempt to determine the optical depth of spiral galaxy disks by a
statistical study of new Tully-Fisher data from the ongoing KLUN+ survey, and
to clarify the difference between the true and apparent behavior of optical
depth. Methods. By utilizing so-called normalized distances, a subsample of the
data is identified to be as free from selection effects as possible. For these
galaxies, a set of apparent quantities are calculated for face-on positions
using the Tully-Fisher diameter and magnitude relations. These values are
compared with direct observations to determine the mean value of the parameter
C describing the optical depth. Results. The present study suggests that spiral
galaxy disks are relatively optically thin tauB = 0.1, at least in the
outermost regions, while they appear in general to be optically thick tauB > 1
when the apparent magnitude and average surface brightness are studied
statistically.


title: On connectedness and indecomposibility of local cohomology modules

abstract:
  Let $I$ denote an ideal of a local Gorenstein ring $(R, \mathfrak m)$. Then
we show that the local cohomology module $H^c_I(R), c = \height I,$ is
indecomposable if and only if $V(I_d)$ is connected in codimension one. Here
$I_d$ denotes the intersection of the highest dimensional primary components of
$I.$ This is a partial extension of a result shown by Hochster and Huneke in
the case $I$ the maximal ideal. Moreover there is an analysis of connectedness
properties in relation to various aspects of local cohomology. Among others we
show that the endomorphism ring of $H^c_I(R)$ is a local Noetherian ring if
$\dim R/I = 1.$


title: Quintom dark energy models with nearly flat potentials

abstract:
  We examine quintom dark energy models, produced by the combined consideration
of a canonical and a phantom field, with nearly flat potentials and dark energy
equation-of-state parameter $w_{DE}$ close to -1. We find that all such models
converge to a single expression for $w_{DE}(z)$, depending only on the initial
field values and their derivatives. We show that this quintom paradigm allows
for a description of the transition through -1 in the near cosmological past.
In addition, we provide the necessary conditions for the determination of the
direction of the -1-crossing.


title:
Identification of Potential Weak Target Radio Quasars for ASTRO-G
  In-Beam Phase-Referencing

abstract:
  We apply an efficient selection method to identify potential weak Very Long
Baseline Interferometry (VLBI) target quasars simply using optical (SDSS) and
low-resolution radio (FIRST) catalogue data. Our search is restricted to within
12" from known compact radio sources that are detectable as phase-reference
calibrators for ASTRO-G at 8.4 GHz frequency. These calibrators have estimated
correlated flux density >20 mJy on the longest ground-space VLBI baselines. The
search radius corresponds to the primary beam size of the ASTRO-G antenna. We
show that ~20 quasars with at least mJy-level expected flux density can be
pre-selected as potential in-beam phase-reference targets for ASTRO-G at 8.4
GHz frequency. Most of them have never been imaged with VLBI. The sample of
these dominantly weak sources offers a good opportunity to study their radio
structures with unprecedented angular resolution provided by Space VLBI. The
method of in-beam phase-referencing is independent from the ability of the
orbiting radio telescope to do rapid position-switching manoeuvres between the
calibrators and the nearby reference sources, and less sensitive to the
satellite orbit determination uncertainties.


title: When weak Hopf algebras are Frobenius

abstract:
  We investigate when a weak Hopf algebra H is Frobenius; we show this is not
always true, but it is true if the semisimple base algebra A has all its matrix
blocks of the same dimension. However, if A is a semisimple algebra not having
this property, there is a weak Hopf algebra H with base A which is not
Frobenius (and consequently, it is not Frobenius "over" A either). We give,
moreover, a categorical counterpart of the result that a Hopf algebra is a
Frobenius algebra for a noncoassociative generalization of weak Hopf algebra.


title:
Implementation of the Duality between Wilson loops and Scattering
  Amplitudes in QCD

abstract:
  We generalize modern ideas about the duality between Wilson loops and
scattering amplitudes in ${\cal N}$=4 SYM to large-N (or quenched) QCD. We show
that the area-law behavior of asymptotically large Wilson loops is dual to the
Regge-Veneziano behavior of scattering amplitudes at high energies and fixed
momentum transfer, when quark mass is small and/or the number of particles is
large. We elaborate on this duality for string theory in a flat space,
identifying the asymptotes of the disk amplitude and the Wilson loop of large-N
QCD.


title: A close look at compact triple radio sources

abstract:
  We show an archival 1.4-GHz Very Large Array (VLA) image of the
core-dominated triple (CDT) radio source J1628+3906, along with a recent
high-resolution 5-GHz Very Long Baseline Interferometry (VLBI) image of its
core. This core is resolved into two nearly symmetric components at ~10
milli-arcsecond (mas) angular scale. The inner structure is markedly misaligned
with respect to the large-scale structure. This morphology can be interpreted
as a possible signature of once ceased and then restarted activity of the
galactic nucleus, coupled with a rapid repositioning of the central radio jet
axis. In a search for compact (<5"), optically identified, and highly
redshifted (z>3) quasars in the Faint Images of the Radio Sky at
Twenty-centimeters (FIRST) and the Sloan Digital Sky Survey (SDSS) catalogues,
we have also found two quasars associated with weaker two-sided radio lobes at
~10" scale. We present archival 1.4-GHz VLA images of these quasars (J1036+1326
and J1353+5725). The compact cores of both of these CDT sources are likely to
be detectable at mas scales. Future VLBI observations at the highest resolution
could reveal if their inner radio structure is similar to that of the Compact
Symmetric Objects (CSOs). The characteristic directions of their
arcsecond-scale and mas-scale structures are probably misaligned which could
also support the "restarting and rapid repositioning" scenario.


title:
Adaptive variance function estimation in heteroscedastic nonparametric
  regression

abstract:
  We consider a wavelet thresholding approach to adaptive variance function
estimation in heteroscedastic nonparametric regression. A data-driven estimator
is constructed by applying wavelet thresholding to the squared first-order
differences of the observations. We show that the variance function estimator
is nearly optimally adaptive to the smoothness of both the mean and variance
functions. The estimator is shown to achieve the optimal adaptive rate of
convergence under the pointwise squared error simultaneously over a range of
smoothness classes. The estimator is also adaptively within a logarithmic
factor of the minimax risk under the global mean integrated squared error over
a collection of spatially inhomogeneous function classes. Numerical
implementation and simulation results are also discussed.


title: The evolution of massive and very massive stars in clusters

abstract:
  The present paper reviews massive star (initial mass smaller than 120 M0) and
very massive star (initial mass larger than 120 M0) evolution. I will focus on
evolutionary facts and questions that may critically affect predictions of
population and spectral synthesis of starburst regions. We discuss the
ever-lasting factor 2 or more uncertainty in the stellar wind mass loss rates.
We may ask ourselves if stellar rotation is one of the keys to understand the
universe, why so many massive stars are binary components and why binaries are
ignored or are considered as the poor cousins by some people? And finally, do
ultra luminous X-ray sources harbor an intermediate mass black hole with a mass
of the order of 1000 M0?


title: Dynamics of vortices for the Complex Ginzburg-Landau equation

abstract:
  We study a complex Ginzburg-Landau equation in the plane, which has the form
of a Gross-Pitaevskii equation with some dissipation added. We focus on the
regime corresponding to well-prepared unitary vortices and derive their
asymptotic motion law.


title: Multi-orbital Anderson models and the Kondo effect

abstract:
  The low energy region of certain transition metal compounds reveals dramatic
correlation effects between electrons, which can be studied by photoelectron
spectroscopy. Theoretical investigations are often based on multi-orbital
impurity models, which reveal modified versions of the Kondo effect. We present
a systematic study of a multi-orbital Anderson-like model, based on a new
semi-analytical impurity solver which goes beyond simple modifications of the
well known NCA. We discuss one-particle excitation spectra and in particular
the role of level positions and Coulomb-matrix elements. It is shown that the
low-energy region as well as the overall features of spectra critically depend
on the model parameters and on the quality of the approximations used. Recent
photoelectron experiments and corresponding existing calculations are put into
perspective. An interesting crossover scenario between different regimes of
ground states with characteristically different local correlations is
uncovered.


title:
Preseismic electric field "strange attractor" like precursor analysis
  applied on large (Ms > 5.5R) EQs, which occurred in Greece during December
  1st, 2007 - April 30th, 2008

abstract:
  In order to investigate the capability of the preseismic electric field
"strange attractor like" precursor as a time predictor of a large EQ within a
short time window (short-term prediction), the specific methodology was applied
on the Earth's electric field recorded during a rather long seismically active
period (December 1st, 2007 - April 30th, 2008) of Greece. During this period of
time a number (8) of large (Ms > 5.5R) earthquakes took place. The particular
analysis is presented in detail for the following EQs: the Monemvasia EQ
(January 6th 2008, Ms = 6.6R), the Methoni EQs (February 14th 2008 Ms = 6.7R,
February 19th 2008 Ms = 5.6R, February 20th 2008 Ms = 6.5R, February 26th 2008
Ms = 5.7R), the Skyros EQ (March 19th 2008 Ms = 5.5R) and the Mid Southern
Creta EQ (March 28th 2008 Ms = 5.6R). The obtained results from the analysis of
the afore mentioned EQs, in conjunction to the ones obtained from an earlier
presentation of the particular methodology (Thanassoulas et al. 2008a),
suggest: an average time of initiation of the preseismic precursor of the order
of (9) days before the EQ occurrence, a precursor average duration of the order
of (7) days, while the elapsed time between the end of the precursor till the
EQ occurrence time is, at average, only (2) days. These results suggest an
objective and easy to apply method for the short-term EQ prediction, based on
the registration of the Earth's electric field on ground surface.


title:
Photon bunching in parametric down-conversion with continuous wave
  excitation

abstract:
  The first direct measurement of photon bunching (g2 correlation function) in
one output arm of a spontaneous-parametric-down-conversion source operated with
a continuous pump laser in the single-photon regime is demonstrated. The result
is in agreement with the statistics of a thermal field of the same coherence
length, and shows the feasibility of investigating photon statistics with
compact cw-pumped sources. Implications for entanglement-based quantum
cryptography are discussed.


title:
Hamiltonian theory for the axial perturbations of a dynamical spherical
  background

abstract:
  We develop the Hamiltonian theory of axial perturbations around a general
time-dependent spherical background spacetime. Using the fact that the
linearized constraints are gauge generators, we isolate the physical and
unconstrained axial gravitational wave in a Hamiltonian pair of variables.
Then, switching to a more geometrical description of the system, we construct
the only scalar combination of them. We obtain the well-known Gerlach and
Sengupta scalar for axial perturbations, with no known equivalent for polar
perturbations. The strategy suggested and tested here will be applied to the
polar case in a separate article.


title:
Finite difference method for transport properties of massless Dirac
  fermions

abstract:
  We adapt a finite difference method of solution of the two-dimensional
massless Dirac equation, developed in the context of lattice gauge theory, to
the calculation of electrical conduction in a graphene sheet or on the surface
of a topological insulator. The discretized Dirac equation retains a single
Dirac point (no "fermion doubling"), avoids intervalley scattering as well as
trigonal warping, and preserves the single-valley time reversal symmetry (=
symplectic symmetry) at all length scales and energies -- at the expense of a
nonlocal finite difference approximation of the differential operator. We
demonstrate the symplectic symmetry by calculating the scaling of the
conductivity with sample size, obtaining the logarithmic increase due to
antilocalization. We also calculate the sample-to-sample conductance
fluctuations as well as the shot noise power, and compare with analytical
predictions.


title:
On the $U_p$ operator acting on $p$-adic overconvergent modular forms
  when $X_0(p)$ has genus 1

abstract:
  In this article we will show how to compute $U_p$ acting on spaces of
overconvergent $p$-adic modular forms when $X_0(p)$ has genus 1. We first give
a construction of Banach bases for spaces of overconvergent $p$-adic modular
forms, and then give an algorithm to approximate both the characteristic power
series of the $U_p$ operator and eigenvectors of finite slope for $U_p$, and
present some explicit examples. We will also relate this to the conjectures of
Clay on the slopes of overconvergent modular forms.


title: The mutation class of $D_n$ quivers

abstract: We give an explicit description of the mutation class of quivers of type D.


title:
Anisotropic itinerant magnetism and spin fluctuations in BaFe2As2: A
  neutron scattering study

abstract:
  Neutron scattering measurements were performed to investigate magnetic
excitations in a single-crystal sample of the ternary iron arsenide BaFe2As2, a
parent compound of a recently discovered family of Fe-based superconductors. In
the ordered state, we observe low energy spin-wave excitations with a gap
energy of 9.8(4) meV. The in-plane spin-wave velocity v_ab and out-of-plane
spin-wave velocity v_c measured at 12 meV are 280(150) and 57(7) meV A,
respectively. At high energy, we observe anisotropic scattering centered at the
antiferromagnetic wave vectors. This scattering indicates two-dimensional spin
dynamics, which possibly exist inside the Stoner continuum. At T_N=136(1) K,
the gap closes, and quasi-elastic scattering is observed above T_N, indicative
of short-range spin fluctuations. In the paramagnetic state, the scattering
intensity along the L direction becomes "rodlike," characteristic of
uncorrelated out-of-plane spins, attesting to the two-dimensionality of the
system.


title:
Comment on "Dynamic Scaling of Non-Euclidean Interfaces"
  [arXiv:0804.1898]

abstract:
  This is the revised version of a Comment on a paper by C. Escudero (Phys.
Rev. Lett. 100, 116101, 2008; arXiv:0804.1898).


title:
On one-to-one correspondence of Gibbs distribution and reduced
  two-particle distribution function

abstract:
  In this article it is shown that in an equilibrium classical canonical
ensemble of molecules with two-body interaction and external field full Gibbs
distribution can be uniquely expressed in terms of a reduced two-particle
distribution function. This means that while a number of particles $N$ and a
volume $V$ are fixed the reduced two-particle distribution function contains as
much information about the equilibrium system as the whole canonical
distribution. The latter is represented as an absolutely convergent power
series relative to the reduced two-particle distribution function. As an
example a linear term of this expansion is calculated. It is also shown that
Gibbs distribution function can de expressed in terms of reduced distribution
function of the first order and pair correlation function.That is the later two
functions contain the whole information about system under consideration.


title: On the Low Surface Magnetic Field Structure of Quark Stars

abstract:
  Following some of the recent articles on hole super-conductivity and related
phenomena by Hirsch \cite{H1,H2,H3}, a simple model is proposed to explain the
observed low surface magnetic field of the expected quark stars. It is argued
that the diamagnetic moments of the electrons circulating in the electro-sphere
induce a magnetic field, which forces the existing quark star magnetic flux
density to become dilute. We have also analysed the instability of
normal-superconducting interface due to excess accumulation of magnetic flux
lines, assuming an extremely slow growth of superconducting phase through a
first order bubble nucleation type transition.


title:
Stability of non-sticking periodic oscillations obtained via the
  averaging method in discontinuous systems. I. Smooth outside of the
  discontinuity surfaces systems

abstract:
  In this paper the statement of the second Bogolyubov's theorem on periodic
solutions of smooth systems with small parameter is justified for
discountinuous systems. It is assumed that the generating solution intersects
the discontinuity hyperplanes transversally and that the system is smooth
outside of these hyperplanes. Such a situation is natural for mechanical
systems with dry friction and without constraints and sticking of oscillations.
To illustrate the result we prove stability of the velocity of
vibration-induced displacement.