title: Cubic polynomials with a parabolic point

abstract:
  We consider the family of cubic polynomials with a simple parabolic fixed
point. We prove that the boundary of the immediate basin of attraction of the
parabolic point is a Jordan curve and give a description of the dynamics.


title: Killing spinor initial data sets

abstract:
  A 3+1 decomposition of the twistor and valence-2 Killing spinor equation is
made using the space spinor formalism. Conditions on initial data sets for the
Einstein vacuum equations are given so that their developments contain
solutions to the twistor and/or Killing equations. These lead to the notions of
twistor and Killing spinor initial data. These notions are used to obtain a
characterisation of initial data sets whose development are of Petrov type N or
D.


title: Fundamental groups of moduli stacks of smooth Weierstrass fibrations

abstract:
  We give finite presentations for the fundamental group of moduli stacks of
smooth Weierstrass curves over complex projective space P^n which extend the
classical result for elliptic curves to positive dimensional base. We thus get
natural generalisations of SL_2(Z) and pave the way to understanding the
fundamental group of moduli stacks of elliptic surfaces in general.
  Our approach exploits the natural involution on Weierstrass curves and the
identification of its fixed loci with smooth hypersurfaces in an appropriate
linear system on a projective line bundle over P^n. The fundamental group of
the corresponding discriminant complement can be presented in terms of finitely
many generators and relations using methods in the Zariski tradition, which
were sucessfully elaborated in mathAG/0602371.


title:
Accurate calculation of the complex eigenvalues of the Schr\"{o}dinger
  equation with an exponential potential

abstract:
  We show that the Riccati--Pad\'{e} method is suitable for the calculation of
the complex eigenvalues of the Schr\"{o}dinger equation with a repulsive
exponential potential. The accuracy of the results is remarkable for realistic
potential parameters.


title: Perturbation Theory for Population Dynamics

abstract:
  We prove that a recently proposed homotopy perturbation method for the
treatment of population dynamics is just the Taylor expansion of the population
variables about initial time. Our results show that this perturbation method
fails to provide the global features of the ecosystem dynamics.


title:
Synthesis and Bulk Properties of Oxychloride Superconductor
  Ca2-xNaxCuO2Cl2

abstract:
  Polycrystalline samples and submillimeter size single crystals of Na-doped
Ca2CuO2Cl2 have been synthesized under high pressure. A series of experiments
showed that the Na content depends not only on the pressure during the
synthesis but also on the synthesis temperature and time. From a comparison of
the Na-CCOC data with those of structurally related La214 cuprate
superconductors we concluded that chlorine at the apical site is less effective
that oxygen in supplying charge carriers to the CuO2 plans. As a result, the
coupling between the CuO2 planes is weakened, the transition temperature Tc is
reduced and the anisotropic nature is enhanced.


title: Scaling Limits for Internal Aggregation Models with Multiple Sources

abstract:
  We study the scaling limits of three different aggregation models on Z^d:
internal DLA, in which particles perform random walks until reaching an
unoccupied site; the rotor-router model, in which particles perform
deterministic analogues of random walks; and the divisible sandpile, in which
each site distributes its excess mass equally among its neighbors. As the
lattice spacing tends to zero, all three models are found to have the same
scaling limit, which we describe as the solution to a certain PDE free boundary
problem in R^d. In particular, internal DLA has a deterministic scaling limit.
We find that the scaling limits are quadrature domains, which have arisen
independently in many fields such as potential theory and fluid dynamics. Our
results apply both to the case of multiple point sources and to the
Diaconis-Fulton smash sum of domains.

categories: math.PR cond-mat.stat-mech math.AP math.CO


title: Expectation values and vacuum currents of quantum fields

abstract:
  Theory of expectation values is presented as an alternative to S-matrix
theory for quantum fields. This change of emphasis is conditioned by a
transition from the accelerator physics to astrophysics and cosmology. The
issues discussed are the time-loop formalism, the Schwinger - Keldysh diagrams,
the effective action, the vacuum currents, and the effect of particle creation.


title: Extending the Overlap Graph for Gene Assembly in Ciliates

abstract:
  Gene assembly is an intricate biological process that has been studied
formally and modeled through string and graph rewriting systems. Recently, a
restriction of the general (intramolecular) model, called simple gene assembly,
has been introduced. This restriction has subsequently been defined as a string
rewriting system. We show that by extending the notion of overlap graph it is
possible to define a graph rewriting system for two of the three types of rules
that make up simple gene assembly. It turns out that this graph rewriting
system is less involved than its corresponding string rewriting system.
Finally, we give characterizations of the `power' of both types of graph
rewriting rules. Because of the equivalence of these string and graph rewriting
systems, the given characterizations can be carried over to the string
rewriting system.


title:
Superconducting gap of overdoped Tl2Ba2CuO6+d observed by Raman
  scattering

abstract:
  We report Raman scattering spectra for single crystals of overdoped
Tl2Ba2CuO6+d (Tl-2201) at low temperatures. It was observed that the
pair-breaking peaks in A1g and B1g spectra radically shift to lower energy with
carrier doping. We interpret it as s-wave component mixing into d-wave,
although the crystal structure is tetragonal. Since similar phenomena were
observed also in YBa2Cu3Oy and Bi2Sr2CaCu2Oz, we conclude that s-wave mixing is
a common property for overdoped high-Tc superconductors.


title:
The Loebl-Komlos-Sos conjecture for trees of diameter 5 and for certain
  caterpillars

abstract:
  Loebl, Komlos, and Sos conjectured that if at least half the vertices of a
graph G have degree at least some k, then every tree with at most k edges is a
subgraph of G. We prove the conjecture for all trees of diameter at most 5 and
for a class of caterpillars. Our result implies a bound on the Ramsey number
r(T,F) of trees T, F from the above classes.


title: Effective Motion of a Virus Trafficking Inside a Biological Cell

abstract:
  Virus trafficking is fundamental for infection success and plasmid cytosolic
trafficking is a key step of gene delivery. Based on the main physical
properties of the cellular transport machinery such as microtubules, motor
proteins, our goal here is to derive a mathematical model to study cytoplasmic
trafficking. Because experimental results reveal that both active and passive
movement are necessary for a virus to reach the cell nucleus, by taking into
account the complex interactions of the virus with the microtubules, we derive
here an estimate of the mean time a virus reaches the nucleus. In particular,
we present a mathematical procedure in which the complex viral movement,
oscillating between pure diffusion and a deterministic movement along
microtubules, can be approximated by a steady state stochastic equation with a
constant effective drift. An explicit expression for the drift amplitude is
given as a function of the real drift, the density of microtubules and other
physical parameters. The present approach can be used to model viral
trafficking inside the cytoplasm, which is a fundamental step of viral
infection, leading to viral replication and in some cases to cell damage.


title: Matsuki's double coset decomposition via gradient maps

abstract:
  Let $G$ be a real-reductive Lie group and let $G_1$ and $G_2$ be two
subgroups given by involutions. We show how the technique of gradient maps can
be used in order to obtain a new proof of Matsuki's parametrization of the
closed double cosets $G_1\backslash G/G_2$ by Cartan subsets. We also describe
the elements sitting in non-closed double cosets.


title: Integrability and Diffeomorphisms on Target Space

abstract:
  We briefly review the concepts of generalized zero curvature conditions and
integrability in higher dimensions, where integrability in this context is
related to the existence of infinitely many conservation laws. Under certain
assumptions, it turns out that these conservation laws are, in fact, generated
by a class of geometric target space transformations, namely the
volume-preserving diffeomorphisms. We classify the possible conservation laws
of field theories for the case of a three-dimensional target space. Further, we
discuss some explicit examples.


title: On the symmetry of minimizers

abstract:
  For a large class of variational problems we prove that minimizers are
symmetric whenever they are $C^1$.


title: Asiago eclipsing binaries program. II. V505 Per

abstract:
  The orbit and fundamental physical parameters of the double-lined eclipsing
binary V505 Per are derived by means of Echelle high resolution, high S/N
spectroscopy and B, V photometry. Effective temperatures, gravities, rotational
velocities and metallicities are obtained from atmospheric chi^2 analysis. An
E(B-V)<=0.01 mag reddening is derived from interstellar NaI and KI lines. The
distance to the system computed from orbital parameters (60.6 +/- 1 pc) is
identical to the newly re-reduced Hipparcos parallax (61.5 +/- 1.9 pc). The
masses of the two components (M(1) = 1.2693 +/- 0.0011 and M(2) = 1.2514 +/-
0.0012 Msun) place them in the transition region between convective and
radiative stellar cores of the HR diagram, with the more massive of the two
showing already the effect of evolution within the Main Sequence band (T(1) =
6512 +/- 21 K, T(2) = 6462 +/- 12 K, R(1) = 1.287 +/- 0.014, R(2) = 1.266 +/-
0.013 Rsun). This makes this system of particular relevance to theoretical
stellar models, as a test on the overshooting. We compare the firm
observational results for V505 Per component stars with the predictions of
various libraries of theoretical stellar models (BaSTI, Padova, Granada,
Yonsei-Yale, Victoria-Regina) as well as BaSTI models computed specifically for
the masses and chemical abundances of V505 Per. We found that the overshooting
at the masses of V505 Per component stars is already pretty low, but not null,
and described by efficiencies lambda(OV)=0.093 and 0.087 for the 1.27 and 1.25
Msun components, respectively. According to the computed BaSTI models, the age
of the system is about 0.9 Gyr and the element diffusion during this time has
reduced the surface metallicity from the initial [M/H]=-0.03 to the current
[M/H]=-0.13, in excellent agreement with observed [M/H]=-0.12 +/- 0.03.


title:
The role of the disk magnetization on the hysteresis behavior of X-ray
  binaries

abstract:
  We present a framework for understanding the dynamical and spectral
properties of X-ray Binaries, where the presence of an organized large scale
magnetic field plays a major role. Such a field is threading the whole
accretion disk with an amplitude measured by the disk magnetization $\mu(r,t)
=B_z^2/(\mu_o P_{tot})$, where $P_{tot}$ is the total, gas and radiation,
pressure.
  Below a transition radius $r_J$, a jet emitting disk (the JED) is settled and
drives self-collimated non relativistic jets. Beyond $r_J$, no jet is produced
despite the presence of the magnetic field and a standard accretion disc (the
SAD) is established. The radial distribution of the disk magnetization $\mu$
adjusts itself to any change of the disk accretion rate $\dot m$, thereby
modifying the transition radius $r_J$.
  We propose that a SAD-to-JED transition occurs locally, at a given radius, in
a SAD when $\mu=\mu_{max} \simeq 1$ while the reverse transition occurs in a
JED only when $\mu=\mu_{min}\simeq 0.1$. This bimodal behavior of the accretion
disk provides a promising way to explain the hysteresis cycles followed by
X-ray binaries during outbursts.


title:
RZBENCH: Performance evaluation of current HPC architectures using
  low-level and application benchmarks

abstract:
  RZBENCH is a benchmark suite that was specifically developed to reflect the
requirements of scientific supercomputer users at the University of
Erlangen-Nuremberg (FAU). It comprises a number of application and low-level
codes under a common build infrastructure that fosters maintainability and
expandability. This paper reviews the structure of the suite and briefly
introduces the most relevant benchmarks. In addition, some widely known
standard benchmark codes are reviewed in order to emphasize the need for a
critical review of often-cited performance results. Benchmark data is presented
for the HLRB-II at LRZ Munich and a local InfiniBand Woodcrest cluster as well
as two uncommon system architectures: A bandwidth-optimized InfiniBand cluster
based on single socket nodes ("Port Townsend") and an early version of Sun's
highly threaded T2 architecture ("Niagara 2").


title: C-Supplemented Subalgebras of Lie Algebras

abstract:
  A subalgebra $B$ of a Lie algebra $L$ is {\em c-supplemented} in $L$ if there
is a subalgebra $C$ of $L$ with $L = B + C$ and $B \cap C \leq B_L$, where
$B_L$ is the core of $B$ in $L$. This is analogous to the corresponding concept
of a c-supplemented subgroup in a finite group. We say that $L$ is {\em
c-supplemented} if every subalgebra of $L$ is c-supplemented in $L$. We give
here a complete characterisation of c-supplemented Lie algebras over a general
field.


title: Quasi-Particle Dynamics in Superconducting Aluminum

abstract:
  The response of superconducting aluminum to electromagnetic radiation is
investigated in a broad frequency (45 MHz to 40 GHz) and temperature range
($T>T_c/2$), by measuring the complex conductivity. While the imaginary part
probes the superfluid density (Cooper-pairs), the real part monitors the
opening of the superconducting energy gap and -- most important here -- the
zero-frequency quasi-particle response. Varying the mean free path gives some
insight into the dynamics, scattering and coherence effects of the
quasi-particles in the superconducting state.


title: On some explicit semi-stable degenerations of toric varieties

abstract:
  We study semi-stable degenerations of toric varieties determined by certain
partitions of their moment polytopes. Analyzing their defining equations we
prove a property of uniqueness.


title:
The evolution of the Non-Fermi Liquid behavior of BaVS$_3$ under high
  pressure

abstract:
  Temperature, pressure, and magnetic field dependencies of the resistivity of
BaVS$_3$ were measured above the critical pressure of $p_{cr}$=2 GPa, which is
associated with the zero temperature insulator-to-metal (MI) transition. The
resistivity exhibits the $T^n$ temperature dependence below $T_g\approx$15 K,
with $n$ of 1.5 at $p_{cr}$, which increases continuously with pressure towards
2. This is interpreted as a crossover from non-Fermi (NFL) to Fermi-liquid (FL)
behavior. Although the spin configuration of the $e_g$ electrons influences the
charge propagation, the NFL behavior is attributed to the pseudogap that
appears in the single particle spectrum of the $d_z^2$ electrons related to
large quasi-one dimensional (Q-1d) 2$k_F$-CDW fluctuations. The non-monotonic
magnetic field dependence of $\Delta$$\rho$/$\rho$ reveals a characteristic
field $B_0\approx$12 T attributed to the full suppression of the pseudogap.


title: Ripples in epitaxial graphene

abstract:
  Graphene outstanding properties directly come from its pecular electronic
structure and thus from the honeycomb lattice symmetry. The way interaction
with the substrate impact this lattice is of primary importance. This is
peculiarly true for epitaxial graphene because of the SiC substrate. The
advantage of this system that produces macroscopic samples in registry with a
substrate could turn to a major drawback if the graphene lattice reveals to be
strongly distorted. Extensive ab initio calculations supported by Scanning
Tunneling Microscopy experiments, demonstrate here that the substrate indeed
induces a strong nanostructuration of the interface carbon layer. It propagates
to the above C layer where it generates incommensurate ripples in the honeycomb
lattice.


title:
Hysteretic behavior at the collapse of the metal-insulator transition in
  BaVS$_3$

abstract:
  Electrical resistivity as a function of temperature, pressure, and magnetic
field was measured in high and low purity single crystals of BaVS$_3$ close to
the critical pressure value $p_{cr}$$\approx$2 GPa, associated with the zero
temperature insulator-to-metal (MI) transition. In the 1.8-2.0 GPa range, where
the MI transition is below $\approx$20 K, one can observe a sudden collapse of
the MI phase boundary upon increasing pressure and at fixed pressure a magnetic
field induced insulator to metal transition. In high quality samples these
features are accompanied by hysteresis in all measured physical quantities as a
function of temperature and magnetic field. We ascribe these observations to
the crossing of the MI and the magnetic phase boundaries upon increasing
pressure.


title:
On an age and spatially structured population model for Proteus
  Mirabilis swarm-colony development

abstract:
  Proteus mirabilis are bacteria that make strikingly regular spatial-temporal
patterns on agar surfaces. In this paper we investigate a mathematical model
that has been shown to display these structures when solved numerically. The
model consists of an ordinary differential equation coupled with a partial
differential equation involving a first-order hyperbolic aging term together
with nonlinear degenerate diffusion. The system is shown to admit global weak
solutions.


title:
Using Energy Conditions to Distinguish Brane Models and Study Brane
  Matter

abstract:
  Current universe (assumed here to be normal matter on the brane) is
pressureless from observations. In this case the energy condition is
$\rho_0\geq0$ and $p_0=0$. By using this condition, brane models can be
distinguished. Then, assuming arbitrary component of matter in DGP model, we
use four known energy conditions to study the matter on the brane. If there is
nonnormal matter or energy (for example dark energy with $w<-1/3$) on the
brane, the universe is accelerated.


title:
Eikonal zeros in the momentum transfer space from proton-proton
  scattering: An empirical analysis

abstract:
  By means of improved empirical fits to the differential cross section data on
$pp$ elastic scattering at $19.4 \le\sqrt{s}\le 62.5$ GeV and making use of a
semi-analytical method, we determine the eikonal in the momentum transfer space
(the inverse scattering problem). This method allows the propagation of the
uncertainties from the fit parameters up to the extracted eikonal, providing
statistical evidence that the imaginary part of the eikonal (real part of the
opacity function) presents a zero (change of signal) in the momentum space, at
$q^2 \approx 7 \pm 1$ GeV$^2$. We discuss the implication of this change of
signal in the phenomenological context, showing that eikonal models with one
zero provide good descriptions of the differential cross sections in the full
momentum transfer range, but that is not the case for models without zero.
Empirical connections between the extracted eikonal and results from a recent
global analysis on the proton electric form factor are also discussed, in
special the Wu-Yang conjecture. In addition, we present a critical review on
the $pp$ differential cross section data presently available at high energies.


title: Introduction to the Photon Collider

abstract:
  The purpose of this Introduction, presented at PHOTON2007, is to provide an
overview of the basic principles, possible parameters, some technical aspects
and the physics program of the photon collider and discuss its status within
the ILC project.


title:
Semistable reduction for overconvergent F-isocrystals, IV: Local
  semistable reduction at nonmonomial valuations

abstract:
  We complete our proof that given an overconvergent F-isocrystal on a variety
over a field of positive characteristic, one can pull back along a suitable
generically finite cover to obtain an isocrystal which extends, with
logarithmic singularities and nilpotent residues, to some complete variety. We
also establish an analogue for F-isocrystals overconvergent inside a partial
compactification. By previous results, this reduces to solving a local problem
in a neighborhood of a valuation of height 1 and residual transcendence degree
0. We do this by studying the variation of some numerical invariants attached
to p-adic differential modules, analogous to the irregularity of a complex
meromorphic connection. This allows for an induction on the transcendence
defect of the valuation, i.e., the discrepancy between the dimension of the
variety and the rational rank of the valuation.


title: The Noncommutative Geometry of the Quantum Projective Plane

abstract:
  We study the spectral geometry of the quantum projective plane CP^2_q, a
deformation of the complex projective plane CP^2, the simplest example of a
spin^c manifold which is not spin. In particular, we construct a Dirac operator
D which gives a 0^+ summable spectral triple, equivariant under U_q(su(3)). The
square of D is a central element for which left and right actions on spinors
coincide, a fact that is exploited to compute explicitly its spectrum.


title: Graph kernels between point clouds

abstract:
  Point clouds are sets of points in two or three dimensions. Most kernel
methods for learning on sets of points have not yet dealt with the specific
geometrical invariances and practical constraints associated with point clouds
in computer vision and graphics. In this paper, we present extensions of graph
kernels for point clouds, which allow to use kernel methods for such ob jects
as shapes, line drawings, or any three-dimensional point clouds. In order to
design rich and numerically efficient kernels with as few free parameters as
possible, we use kernels between covariance matrices and their factorizations
on graphical models. We derive polynomial time dynamic programming recursions
and present applications to recognition of handwritten digits and Chinese
characters from few training examples.


title: Heavy Cosmic Ray Nuclei from Extragalactic Sources above 'The Ankle'

abstract:
  A very recent observation by the Auger Observatory group claims strong
evidence for cosmic rays above 56 EeV being protons from Active Galactic
Nuclei. If, as would be expected, the particles above the ankle at about 2 EeV
are almost all of extragalactic origin then it follows that the characteristics
of the nuclear interactions of such particles would need to be very different
from conventional expectation -- a result that follows from the measured
positions of 'shower maximum' in the Auger' work. Our own analysis gives a
different result, viz that the detected particles are still 'massive'
specifically with a mean value of <ln A> = 2.2 +- 0.8. The need for a dramatic
change in the nuclear physics disappears.


title: Taking dibaryon fields seriously

abstract:
  We propose a low energy effective field theory of QCD at the scale of pion
mass for the $N_B=2$ sector, $N_B$ being the baryon number, which contains two
dibaryon fields in addition to the nucleons and pions. It has a well defined
counting, is renormalizable and the nucleon-nucleon scattering amplitudes are
manifestly unitary at leading order. We work out a lower energy effective
theory for nucleons with energy much lower than the pion mass and three
momentum comparable to it, which also has a well defined counting and is
renormalizable. The dibaryon fields must also be kept as explicit degrees of
freedom in this theory. We calculate the scattering amplitudes at
next-to-leading order for the $^1S_0$ and $^3S_1$ channels in this framework
and obtain an excellent description of the phase shifts for center of mass
energies in the $0-50 MeV$ range.


title: Chiral tensor fields and spontaneous breaking of Lorentz symmetry

abstract:
  Antisymmetric tensor fields interacting with quarks and leptons have been
proposed as a possible solution to the gauge hierarchy problem. We compute the
one-loop beta function for a quartic self-interaction of the chiral
antisymmetric tensor fields. Fluctuations of the top quark drive the
corresponding running coupling to a negative value as the renormalization scale
is lowered. This may indicate a non-vanishing expectation value of the tensor
field, and thus a spontaneous breaking of Lorentz invariance. Settling this
issue will need the inclusion of tensor loops.


title:
Projective manifolds containing a large linear subspace with nef normal
  bundle

abstract:
  We classify smooth complex projective varieties $X \subset \proj^N$ of
dimension $2s+1$ containing a linear subspace $\Lambda$ of dimension $s$ whose
normal bundle $N_{\Lambda/X}$ is numerically effective.


title:
The Critical Exponent of the Fractional Langevin Equation is
  $\alpha_c\approx 0.402$

abstract:
  We investigate the dynamical phase diagram of the fractional Langevin
equation and show that critical exponents mark dynamical transitions in the
behavior of the system. For a free and harmonically bound particle the critical
exponent $\alpha_c= 0.402\pm 0.002$ marks a transition to a non-monotonic
under-damped phase. The critical exponent $\alpha_{R}=0.441...$ marks a
transition to a resonance phase, when an external oscillating field drives the
system. Physically, we explain these behaviors using a cage effect, where the
medium induces an elastic type of friction. Phase diagrams describing the
under-damped, the over-damped and critical frequencies of the fractional
oscillator, recently used to model single protein experiments, show behaviors
vastly different from normal.


title:
3-D non-linear evolution of a magnetic flux tube in a spherical shell:
  the isentropic case

abstract:
  We present recent 3-D MHD numerical simulations of the non-linear dynamical
evolution of magnetic flux tubes in an adiabatically stratified convection zone
in spherical geometry, using the anelastic spherical harmonic (ASH) code. We
seek to understand the mechanism of emergence of strong toroidal fields from
the base of the solar convection zone to the solar surface as active regions.
We confirm the results obtained in cartesian geometry that flux tubes that are
not twisted split into two counter vortices before reaching the top of the
convection zone. Moreover, we find that twisted tubes undergo the poleward-slip
instability due to an unbalanced magnetic curvature force which gives the tube
a poleward motion both in the non-rotating and in the rotating case. This
poleward drift is found to be more pronounced on tubes originally located at
high latitudes. Finally, rotation is found to decrease the rise velocity of the
flux tubes through the convection zone, especially when the tube is introduced
at low latitudes.


title: CSW rules for a massive scalar

abstract:
  We derive the analog of the Cachazo-Svrcek-Witten (CSW) diagrammatic Feynman
rules for four dimensional Yang-Mills gauge theory coupled to a massive colored
scalar. The mass term is shown to give rise to a new tower of vertices in
addition to the CSW vertices for massless scalars in non-supersymmetric
theories. The rules are derived directly from an action, once through a
canonical transformation within light-cone Yang-Mills and once by the
construction of a twistor action. The rules are tested against known results in
several examples and are used to simplify the proof of on-shell recursion
relations for amplitudes with massive scalars.


title: Tauberian theorems and large deviations

abstract:
  The link between Tauberian theorems and large deviations is surveyed, with
particular reference to regular variation.


title:
The Parabolic Two-Phase Membrane Problem: Regularity in Higher
  Dimensions

abstract:
  For the parabolic obstacle-problem-like equation $$\Delta u - \partial_t u =
\lambda_+ \chi_{\{u>0\}} - \lambda_- \chi_{\{u<0\}} ,$$ where $\lambda_+$ and
$\lambda_-$ are positive Lipschitz functions, we prove in arbitrary finite
dimension that the free boundary $\partial\{u>0\} \cup\partial\{u<0\}$ is in a
neighborhood of each ``branch point'' the union of two Lipschitz graphs that
are continuously differentiable with respect to the space variables. The result
extends the elliptic paper \cite{imrn} to the parabolic case. The result is
optimal in the sense that the graphs are in general not better than Lipschitz,
as shown by a counter-example.


title: Universality in Two-Dimensional Enhancement Percolation

abstract:
  We consider a type of dependent percolation introduced by Aizenman and
Grimmett, who showed that certain "enhancements" of independent (Bernoulli)
percolation, called essential, make the percolation critical probability
strictly smaller. In this paper we first prove that, for two-dimensional
enhancements with a natural monotonicity property, being essential is also a
necessary condition to shift the critical point. We then show that (some)
critical exponents and the scaling limit of crossing probabilities of a
two-dimensional percolation process are unchanged if the process is subjected
to a monotonic enhancement that is not essential. This proves a form of
universality for all dependent percolation models obtained via a monotonic
enhancement (of Bernoulli percolation) that does not shift the critical point.
For the case of site percolation on the triangular lattice, we also prove a
stronger form of universality by showing that the full scaling limit is not
affected by any monotonic enhancement that does not shift the critical point.


title:
An explanatory model to validate the way water activity rules periodic
  terrace generation in Proteus mirabilis swarm

abstract:
  In this paper we explain the biophysical principles which, according to us,
govern the Proteus mirabilis swarm phenomenon. Then, we translate this
explanation into a mathematical model, essentially based on partial
differential equations. This model is then implemented using numerical methods
of the finite volume type in order to make simulations. The simulations show
most of the characteristics which are observed in situ and in particular the
terrace generation.


title: A note on the supremum of a stable process

abstract:
  If $X$ is a spectrally positive stable process of index $\alpha\in(1,2)$
whose L\'{e}vy measure has density $cx^{-\alpha-1}$ on $(0,\infty),$ and
$S_1=\sup_{0<t\leq1}X_t,$ it is known that $P(S_1>x)\backsim
c\alpha^{-1}x^{-\alpha}$ as $x\to\infty.$ It is also known that $S_1$has a
continuous density, $s$ say. The point of this note is to show that
$s(x)\backsim cx^{-(\alpha+1)}$ as $x\to\infty.$


title: Predicting the Last Zero of Brownian Motion with Drift

abstract:
  Given a standard Brownian motion $B^{\mu}=(B_t^{\mu})_{0\le t\le T}$ with
drift $\mu \in IR$ and letting $g$ denote the last zero of $B^{\mu}$ before
$T$, we consider the optimal prediction problem
  V_*=\inf_{0\le \tau \le T}\mathsf {E}\:|\:g-\tau |
  where the infimum is taken over all stopping times $\tau$ of $B^{\mu}$.
Reducing the optimal prediction problem to a parabolic free-boundary problem
and making use of local time-space calculus techniques, we show that the
following stopping time is optimal:
  \tau_*=\inf {t\in [0,T] | B_t^{\mu} \le b_-(t) or B_t^{\mu} \ge b_+(t)}
  where the function $t\mapsto b_-(t)$ is continuous and increasing on $[0,T]$
with $b_-(T)=0$, the function $t\mapsto b_+(t)$ is continuous and decreasing on
$[0,T]$ with $b_+(T)=0$, and the pair $b_-$ and $b_+$ can be characterised as
the unique solution to a coupled system of nonlinear Volterra integral
equations. This also yields an explicit formula for $V_*$ in terms of $b_-$ and
$b_+$. If $\mu=0$ then $b_-=-b_+$ and there is a closed form expression for
$b_{\pm}$ as shown in [10] using the method of time change from [4]. The latter
method cannot be extended to the case when $\mu \ne 0$ and the present paper
settles the remaining cases using a different approach.


title: Stochastic Homogenization of Reflected Diffusion Processes

abstract:
  We investigate a functional limit theorem (homogenization) for Reflected
Stochastic Differential Equations on a half-plane with stationary coefficients
when it is necessary to analyze both the effective Brownian motion and the
effective local time. We prove that the limiting process is a reflected
non-standard Brownian motion. Beyond the result, this problem is known as a
prototype of non-translation invariant problem making the usual method of the
"environment as seen from the particle" inefficient.


title: Repeated Quantum Interactions and Unitary Random Walks

abstract:
  Among the discrete evolution equations describing a quantum system $\rH_S$
undergoing repeated quantum interactions with a chain of exterior systems, we
study and characterize those which are directed by classical random variables
in $\RR^N$. The characterization we obtain is entirely algebraical in terms of
the unitary operator driving the elementary interaction. We show that the
solutions of these equations are then random walks on the group $U(\rH_0)$ of
unitary operators on $\rH_0$.


title: Statistical properties of Pauli matrices going through noisy channels

abstract:
  We study the statistical properties of the triplet
$(\sigma_x,\sigma_y,\sigma_z)$ of Pauli matrices going through a sequence of
noisy channels, modeled by the repetition of a general, trace-preserving,
completely positive map. We show a non-commutative central limit theorem for
the distribution of this triplet, which shows up a 3-dimensional Brownian
motion in the limit with a non-trivial covariance matrix. We also prove a large
deviation principle associated to this convergence, with an explicit rate
function depending on the stationary state of the noisy channel.


title: Measurement of Quantum Fluctuations in Geometry

abstract:
  A particular form for the quantum indeterminacy of relative spacetime
position of events is derived from the limits of measurement possible with
Planck wavelength radiation. The indeterminacy predicts fluctuations from a
classically defined geometry in the form of ``holographic noise'' whose spatial
character, absolute normalization, and spectrum are predicted with no
parameters. The noise has a distinctive transverse spatial shear signature, and
a flat power spectral density given by the Planck time. An interferometer
signal displays noise due to the uncertainty of relative positions of
reflection events. The noise corresponds to an accumulation of phase offset
with time that mimics a random walk of those optical elements that change the
orientation of a wavefront. It only appears in measurements that compare
transverse positions, and does not appear at all in purely radial position
measurements. A lower bound on holographic noise follows from a covariant upper
bound on gravitational entropy. The predicted holographic noise spectrum is
estimated to be comparable to measured noise in the currently operating
interferometer GEO600. Because of its transverse character, holographic noise
is reduced relative to gravitational wave effects in other interferometer
designs, such as LIGO, where beam power is much less in the beamsplitter than
in the arms.


title: Cumulative record times in a Poisson process

abstract:
  We obtain a strong law of large numbers and a functional central limit
theorem, as $t\to\infty$, for the number of records up to time $t$ and the
Lebesgue measure (length) of the subset of the time interval $[0,t]$ during
which the Poisson process is in a record lifetime.


title: Large deviations for directed percolation on a thin rectangle

abstract:
  Following the recent investigations of Baik and Suidan in \cite{baik2005gcl}
and Bodineau and Martin in \cite{bodineau2005upl}, we prove large deviation
properties for a last-passage percolation model in $\mathbb{Z}^{2}_{+}$ whose
paths are close to the axis. The results are mainly obtained when the random
weights are Gaussian or have a finite moment-generating function and rely, as
in \cite{baik2005gcl} and \cite{bodineau2005upl}, on an embedding in Brownian
paths and the KMT approximation. The study of the subexponential case completes
the exposition.


title:
Large-N Limit of Crossing Probabilities, Discontinuity, and Asymptotic
  Behavior of Threshold Values in Mandelbrot's Fractal Percolation Process

abstract:
  We study Mandelbrot's percolation process in dimension $d \geq 2$. The
process generates random fractal sets by an iterative procedure which starts by
dividing the unit cube $[0,1]^d$ in $N^d$ subcubes, and independently retaining
or discarding each subcube with probability $p$ or $1-p$ respectively. This
step is then repeated within the retained subcubes at all scales. As $p$ is
varied, there is a percolation phase transition in terms of paths for all $d
\geq 2$, and in terms of $(d-1)$-dimensional "sheets" for all $d \geq 3$.
  For any $d \geq 2$, we consider the random fractal set produced at the
path-percolation critical value $p_c(N,d)$, and show that the probability that
it contains a path connecting two opposite faces of the cube $[0,1]^d$ tends to
one as $N \to \infty$. As an immediate consequence, we obtain that the above
probability has a discontinuity, as a function of $p$, at $p_c(N,d)$ for all
$N$ sufficiently large. This had previously been proved only for $d=2$ (for any
$N \geq 2$). For $d \geq 3$, we prove analogous results for sheet-percolation.
  In dimension two, Chayes and Chayes proved that $p_c(N,2)$ converges, as $N
\to \infty$, to the critical density $p_c$ of site percolation on the square
lattice. Assuming the existence of the correlation length exponent $\nu$ for
site percolation on the square lattice, we establish the speed of convergence
up to a logarithmic factor. In particular, our results imply that
$p_c(N,2)-p_c=(\frac{1}{N})^{1/\nu+o(1)}$ as $N \to \infty$, showing an
interesting relation with near-critical percolation.


title: Tuplix Calculus

abstract:
  We introduce a calculus for tuplices, which are expressions that generalize
matrices and vectors. Tuplices have an underlying data type for quantities that
are taken from a zero-totalized field. We start with the core tuplix calculus
CTC for entries and tests, which are combined using conjunctive composition. We
define a standard model and prove that CTC is relatively complete with respect
to it. The core calculus is extended with operators for choice, information
hiding, scalar multiplication, clearing and encapsulation. We provide two
examples of applications; one on incremental financial budgeting, and one on
modular financial budget design.


title: An analysis of two modifications of the Petersburg game

abstract:
  Two modifications of the Petersburg game are considered: 1. Truncation, so
that the player has a finite capital at his disposal. 2. A cost of borrowing
capital, so that the player has to pay interest on the capital needed. In both
cases limit theorems for the total net gain are derived, so that it is easy to
judge if the game is favourable or not.


title:
Symmetry approaches for reductions of PDEs, differential constraints and
  Lagrange-Charpit method

abstract:
  Many methods for reducing and simplifying differential equations are known.
They provide various generalizations of the original symmetry approach of
Sophus Lie. Plenty of relations between them have been noticed and in this note
a unifying approach will be discussed. It is rather close to the classical
differential constraint method, but we provide certain rigorous results basing
on recent advances in compatibility theory of non-linear overdetermined systems
and homological methods for PDEs.


title: A polymer in a multi-interface medium

abstract:
  We consider a model for a polymer chain interacting with a sequence of
equispaced flat interfaces through a pinning potential. The intensity $\delta
\in \mathbb {R}$ of the pinning interaction is constant, while the interface
spacing $T=T_N$ is allowed to vary with the size $N$ of the polymer. Our main
result is the explicit determination of the scaling behavior of the model in
the large $N$ limit, as a function of $(T_N)_N$ and for fixed $\delta >0$. In
particular, we show that a transition occurs at $T_N=O(\log N)$. Our approach
is based on renewal theory.


title:
On the Simbol-X capability of detecting red/blue-shifted emission and
  absorption Fe K lines

abstract:
  The detection of red/blue-shifted iron lines in the spectra of astronomical
X-ray sources is of great importance, as it allows to trace the environment
around compact objects, like black holes in AGNs. We report on extensive
simulations to test the Simbol-X capability of detecting such spectral
features, focusing on the low energy detector (0.5-30 keV).


title: On Financial Markets Based on Telegraph Processes

abstract:
  The paper develops a new class of financial market models. These models are
based on generalized telegraph processes: Markov random flows with alternating
velocities and jumps occurring when the velocities are switching. While such
markets may admit an arbitrage opportunity, the model under consideration is
arbitrage-free and complete if directions of jumps in stock prices are in a
certain correspondence with their velocity and interest rate behaviour. An
analog of the Black-Scholes fundamental differential equation is derived, but,
in contrast with the Black-Scholes model, this equation is hyperbolic. Explicit
formulas for prices of European options are obtained using perfect and quantile
hedging.


title: On Evolutionary Spatial Heterogeneous Games

abstract:
  How coperation between self-interested individuals evolve is a crucial
problem, both in biology and in social sciences, that is far from being well
understood. Evolutionary game theory is a useful approach to this issue. The
simplest model to take into account the spatial dimension in evolutionary games
is in terms of cellular automata with just a one-parameter payoff matrix. Here,
the effects of spatial heterogeneities of the environment and/or asymmetries in
the interactions among the individuals are analysed through different
extensions of this model. Instead of using the same universal payoff matrix,
bimatrix games in which each cell at site (i,j) has its own different
`temptation to defect' parameter T(i,j) are considered. Firstly, the case in
which these individual payoffs are constant in time is studied. Secondly, an
evolving evolutionary spatial game such that T=T(i,j;t), i.e. besides depending
on the position evolves (by natural selection), is used to explore the
combination of spatial heterogeneity and natural selection of payoff matrices.


title:
Extending ring derivations to right and symmetric rings and modules of
  quotients

abstract:
  We define and study the symmetric version of differential torsion theories.
We prove that the symmetric versions of some of the existing results on
derivations on right modules of quotients hold for derivations on symmetric
modules of quotients. In particular, we prove that the symmetric Lambek, Goldie
and perfect torsion theories are differential.
  We also study conditions under which a derivation on a right or symmetric
module of quotients extends to a right or symmetric module of quotients with
respect to a larger torsion theory. Using these results, we study extensions of
ring derivations to maximal, total and perfect right and symmetric rings of
quotients.


title: The breakdown of the mean-field description of the Nagaoka phase

abstract:
  We discuss the relevance of the improved mean-field slave-fermion theory to
describe the Nagaoka ($U=\infty$) limit of the Hubbard model. In this theory
the crucial on-site constraint of no double electron occupancy is taken into
account rigorously prior to the mean-field approximation. At one-loop
approximation the effective mean-field action shows a long-range ferromagnetic
order over the whole doping range. This indicates that the slave-fermion
mean-field theory does not constitute an appropriate framework to describe the
physics of the Nagaoka phase. We discuss the drawbacks of this mean-field
theory and present some results on the derivation of a low-energy effective
spin action to describe the Nagaoka phase beyond the mean-field approximation.


title: Statistical analysis of redundant systems with "warm" stand-by units

abstract:
  Mathematical formulation of fluent switching from "warm" to "hot" conditions
of standby units is given using the well known Sedyakin's and accelerated
failure time (AFT) models. Non-parametric estimators of cumulative distribution
function and mean failure time of a redundant system with several stand-by
units are proposed. Goodness-of-fit tests for two given models are given.


title: AccelKey Selection Method for Mobile Devices

abstract:
  Portable Electronic Devices usually utilize a small screen with limited
viewing area and a keyboard with a limited number of keys. This makes it
difficult to perform quick searches in data arrays containing more than dozen
items such an address book or song list. In this article we present a new data
selection method which allows the user to quickly select an entry from a list
using 4-way navigation device such as joystick, trackball or 4-way key pad.
This method allows for quick navigation using just one hand, without looking at
the screen.


title:
A new imprint of fast rotators: low 12C/13C ratios in extremely
  metal-poor halo stars

abstract:
  (abridged) Fast stellar rotation is currently the most promising mechanism
for producing primary nitrogen in metal-poor massive stars. Chemical evolution
models computed with the inclusion of the yields of fast rotating models at a
metallicity $Z=10^{-8}$ can account for the high N/O abundances observed in
normal metal-poor halo stars. If, as believed, intermediate mass stars did not
have enough time to contribute to the interstellar medium enrichment at such
low metallicities, the above result constitutes a strong case for the existence
of fast rotators in the primordial Universe. An important result of stellar
models of fast rotators is that large quantities of primary 13C are produced.
Hence, our goal is to investigate the consequence of fast rotation on the
evolution of the 12C/13C ratio in the interstellar medium at low metallicity.
We predict that, if fast rotating massive stars were common phenomena in the
early Universe, the primordial interstellar medium of galaxies with a star
formation history similar to the one inferred for our galactic halo should have
12C/13C ratios between 30-300. Without fast rotators, the predicted 12C/13C
ratios would be $\sim$ 4500 at [Fe/H]=-3.5, increasing to $\sim$ 31000 at
around [Fe/H]=-5.0. Current data on very metal-poor giant normal stars in the
galactic halo agree better with chemical evolution models including fast
rotators. To test our predictions, challenging measurements of the 12C/13C in
more extremely metal-poor giants and turnoff stars are required.


title: How to acknowledge hypercomputation?

abstract:
  We discuss the question of how to operationally validate whether or not a
"hypercomputer" performs better than the known discrete computational models.


title:
Bose-Einstein Condensation from a Rotating Thermal Cloud: Vortex
  Nucleation and Lattice Formation

abstract:
  We develop a stochastic Gross-Pitaveskii theory suitable for the study of
Bose-Einstein condensation in a {\em rotating} dilute Bose gas. The theory is
used to model the dynamical and equilibrium properties of a rapidly rotating
Bose gas quenched through the critical point for condensation, as in the
experiment of Haljan et al. [Phys. Rev. Lett., 87, 21043 (2001)]. In contrast
to stirring a vortex-free condensate, where topological constraints require
that vortices enter from the edge of the condensate, we find that phase defects
in the initial non-condensed cloud are trapped en masse in the emerging
condensate. Bose-stimulated condensate growth proceeds into a disordered vortex
configuration. At sufficiently low temperature the vortices then order into a
regular Abrikosov lattice in thermal equilibrium with the rotating cloud. We
calculate the effect of thermal fluctuations on vortex ordering in the final
gas at different temperatures, and find that the BEC transition is accompanied
by lattice melting associated with diminishing long range correlations between
vortices across the system.


title:
Chiral corrections to the vector and axial couplings of quarks and
  baryons

abstract:
  We calculate chiral corrections to the semileptonic vector and axial quark
coupling constants using a manifestly Lorentz covariant chiral quark approach
up to order O(p4) in the two- and tree-flavor picture. These couplings are then
used in the evaluation of the corresponding couplings which govern the
semileptonic transitions between octet baryon states. In the calculation of
baryon matrix elements we use a general ansatz for the spatial form of the
quark wave function, without referring to a specific realization of
hadronization and confinement of quarks in baryons. Matching the physical
amplitudes calculated within our approach to the model-independent predictions
of baryon chiral perturbation theory (ChPT) allows one to deduce the connection
between our parameters and those of baryon ChPT.


title:
Consequences of Zeeman Degeneracy for van der Waals Blockade between
  Rydberg Atoms

abstract:
  We analyze the effects of Zeeman degeneracies on the long-range interactions
between like Rydberg atoms, with particular emphasis on applications to quantum
information processing using van der Waals blockade. We present a general
analysis of how degeneracies affect the primary error sources in blockade
experiments, emphasizing that blockade errors are sensitive primarily to the
weakest possible atom-atom interactions between the degenerate states, not the
mean interaction strength. We present explicit calculations of the van der
Waals potentials in the limit where the fine-structure interaction is large
compared to the atom-atom interactions. The results are presented for all
potential angular momentum channels invoving s, p, and d states. For most
channels there are one or more combinations of Zeeman levels that have
extremely small dipole-dipole interactions and are therefore poor candidates
for effective blockade experiments. Channels with promising properties are
identified and discussed. We also present numerical calculations of Rb and Cs
dipole matrix elements and relevant energy levels using quantum defect theory,
allowing for convenient quantitative estimates of the van der Waals
interactions to be made for principal quantum numbers up to 100. Finally, we
combine the blockade and van der Waals results to quantitatively analyze the
angular distribution of the blockade shift and its consequence for angular
momentum channels and geometries of particular interest for blockade
experiments with Rb.


title: Ground-state fidelity of Luttinger liquids: A wave functional approach

abstract:
  We use a wave functional approach to calculate the fidelity of ground states
in the Luttinger liquid universality class of one-dimensional gapless quantum
many-body systems. The ground-state wave functionals are discussed using both
the Schrodinger (functional differential equation) formulation and a path
integral formulation. The fidelity between Luttinger liquids with Luttinger
parameters K and K' is found to decay exponentially with system size, and to
obey the symmetry F(K,K')=F(1/K,1/K') as a consequence of a duality in the
bosonization description of Luttinger liquids.


title: Domains of attraction of the random vector $(X,X^2)$ and applications

abstract:
  Many statistics are based on functions of sample moments. Important examples
are the sample variance $s_{n-1}^2$, the sample coefficient of variation SV(n),
the sample dispersion SD(n) and the non-central $t$-statistic $t(n)$. The
definition of these quantities makes clear that the vector defined by
  (\sum_{i=1}^nX_i,\sum_{i=1}^nX_i^2)
  plays an important role. In studying the asymptotic behaviour of this vector
we start by formulating best possible conditions under which the vector
$(X,X^2)$ belongs to a bivariate domain of attraction of a stable law. This
approach is new, uniform and simple. Our main results include a full discussion
of the asymptotic behaviour of SV(n), SD(n) and $t^2(n)$. For simplicity, in
restrict ourselves to positive random variables $X$.


title:
Combining Lens Distortion and Depletion to Map the Mass Distribution of
  A1689

abstract:
  [Abridged] We derive a projected 2D mass map of the well studied galaxy
cluster A1689 based on an entropy-regularized maximum-likelihood combination of
the lens magnification and distortion of red background galaxies registered in
deep Subaru images. The known strong lensing information is also readily
incorporated in this approach, represented as a central pixel with a mean
surface density close to the critical value. We also utilize the distortion
measurements to locally downweight the intrinsic clustering noise, which
otherwise perturbs the depletion signal. The projected mass profile
continuously steepens with radius and is well fitted by the NFW model, but with
a surprising large concentration c_vir=13.4^{+5.3}_{-3.3}, lying far from the
predicted value of c_vir ~ 5, corresponding to the measured virial mass,
M_vir=(2.1\pm 0.2)\times 10^15M_{\odot}, posing a challenge to the standard
assumptions defining the LCDM model. We examine the consistency of our results
with estimates derived with the standard weak lensing estimators and by
comparison with the inner mass profile obtained from strong lensing. All the
reconstructions tested here imply a virial mass in the range,
M_vir=(1.5-2.1)\times 10^15M_{\odot}, and the combined ACS and Subaru-2D mass
reconstruction yields a tight constraint on the concentration parameter,
c_vir=12.7 \pm 1(stat.) \pm 2.8(systematic) (c_200 ~ 10), improving upon the
statistical accuracy of our earlier 1D analysis. Importantly, our best fitting
profile properly reproduces the observed Einstein radius of 45 arcsec (z_s=1),
in contrast to other weak lensing work, reporting lower concentration profiles,
which underestimate the observed Einstein radius.


title:
Multivariate Regular Variation on Cones: Application to Extreme Values,
  Hidden Regular Variation and Conditioned Limit Laws

abstract:
  We attempt to bring some modest unity to three subareas of heavy tail
analysis and extreme value theory: limit laws for componentwise maxima of iid
random variables;hidden regular variation and asymptotic
independence;conditioned limit laws when one component of a random vector is
extreme. The common theme is multivariate regular variation on a cone and the
three cases cited come from specifying the cones $[0,\infty]^d\setminus
\{\boldsymbol 0\};(0,\infty]^d;$ and $[0,\infty]\times (0,\infty]$.


title: Introductory lectures on jet quenching in heavy ion collisions

abstract:
  Jet quenching has become an essential signal for the characterization of the
medium formed in experiments of heavy-ion collisions. After a brief
introduction to the field, we present the full derivation of the medium-induced
gluon radiation spectrum, starting from the diagrammatical origin of the Wilson
lines and the medium averages and including all intermediate steps. The
application of this spectrum to actual phenomenological calculations is then
presented, making comparisons with experimental data and indicating some
improvements of the formalism to the future LHC program. The last part of the
lectures reviews calculations based on the AdS/CFT correspondence on the medium
parameters controlling the jet quenching phenomenon.


title: Partial monoids and Dold-Thom functors

abstract:
  Dold-Thom functors are generalizations of infinite symmetric products, where
integer multiplicities of points are replaced by composable elements of a
partial abelian monoid. It is well-known that for any connective homology
theory, the machinery of $\Gamma$-spaces produces the corresponding linear
Dold-Thom functor. In this note we construct such functors directly from
spectra by exhibiting a partial monoid corresponding to a spectrum.


title:
Heavy absorption and soft X-ray emission lines in the XMM-Newton
  spectrum of the Type 2 radio-loud quasar 3C 234

abstract:
  We report results on a 40 ks XMM-Newton observation of the Type 2 quasar 3C
234. Optical spectropolarimetric data have demonstrated the presence of a
hidden broad-line region in this powerful (M_V <~ -24.2 after reddening and
starlight correction) narrow-line FRII radio galaxy. Our analysis is aimed at
investigating the X-ray spectral properties of this peculiar source which have
remained poorly known so far. We analyze the 0.5--10 keV spectroscopic data
collected by the EPIC cameras in 2006. The X-ray spectrum of this radio-loud
quasar is typical of a local Compton-thin Seyfert 2 galaxy. It exhibits strong
absorption (Nh~3.5 x 10^{23} cm^{-2}) and a narrow, neutral Fe Kalpha emission
line with an equivalent width of ~140+/-40 eV. Our observation also reveals
that the soft portion of the spectrum is characterized by strong emission lines
with a very low level of scattered primary continuum. A possible explanation of
these features in terms of thermal emission from a two-temperature
collisionally ionized plasma emission seems to be unlikely due to the high
luminosity estimated for this component (L(0.5-2) ~ 6 x 10^{42} erg/s). It is
likely that most of the soft X-ray emission originates from a photoionized
plasma as commonly observed in obscured, radio-quiet Seyfert-like AGNs. This
X-ray observation has definitively confirmed the presence of a hidden quasar in
3C 234. The line-rich spectrum and the steepness of the hard X-ray continuum
(Gamma ~ 1.7) found in this source weaken the hypothesis that the bulk ofthe
X-ray emission in radio-loud AGNs with high excitation optical lines arises
from jet non-thermal emission.


title: Vortex Dynamics at the transition to the normal state in YBCO films

abstract:
  We propose a description of the vortex dynamics in YBCO films from the
critical to the normal states. This description supposes that the vortex motion
is thermally activated along the twin boundaries of the films. The
discontinuity observed in the current-voltage curves at the transition to the
normal state is explained by the sudden increase in the dissipated power rate
due to vortex depinning. However, near the critical temperature, this
phenomenon does not occur because the vortex activation energy is near zero. We
also show how the current at the transition to the normal state can be computed
from the current-voltage curves measured at low currents. The predictions of
this description are compared to the data published by Gonzalez et al.
[Phys.Rev.B68,054514 (2003)].


title: Lambda and Antilambda polarization in Au-Au collisions at RHIC

abstract:
  Recent experiments at RHIC have shown that in 200 GeV Au-Au collisions, the
Lambda and Antilambda hyperons are produced with very small polarizations [1],
almost consistent with zero. These results can be understood in terms of a
model that we recently proposed [2]. In this work, we show how this model may
be applied in such collisions, and also will discuss the relation of our
results with other models, in order to explain the experimental data.


title: First principles study of Si(335)-Au surface

abstract:
  The structural and electronic properties of gold decorated Si(335) surface
are studied by means of density-functional calculations. The resulting
structural model indicates that the Au atoms substitute some of the Si atoms in
the middle of the terrace in the surface layer. Calculated electronic band
structure near the Fermi energy features two metallic bands, one coming from
the step edge Si atoms and the other one having its origin in hybridization
between the Au and neighboring Si atoms in the middle of the terrace. The
obtained electronic bands remain in good agreement with photoemission data.


title: The elementary obstruction and the Weil restriction

abstract:
  In this text we investigate the good behaviour of the elementary obstruction,
introduced by Colliot-Thelene and Sansuc. This is an obstruction to the
existence of a rational points on certain algebraic varieties. Assuming some
conditions on the Picard group, we prove that the elementary obstruction
behaves well under the Weil restriction of a variety.


title: Thawing quintessence with a nearly flat potential

abstract:
  The thawing quintessence model with a nearly flat potential provides a
natural mechanism to produce an equation of state parameter, w, close to -1
today. We examine the behavior of such models for the case in which the
potential satisfies the slow roll conditions: [(1/V)(dV/dphi)]^2 << 1 and
(1/V)(d^2 V/dphi^2) << 1, and we derive the analog of the slow-roll
approximation for the case in which both matter and a scalar field contribute
to the density. We show that in this limit, all such models converge to a
unique relation between 1+w, Omega_phi, and the initial value of
(1/V)(dV/dphi). We derive this relation, and use it to determine the
corresponding expression for w(a), which depends only on the present-day values
for w and Omega_phi. For a variety of potentials, our limiting expression for
w(a) is typically accurate to within delta w < 0.005 for w<-0.9. For redshift z
< 1, w(a) is well-fit by the Chevallier-Polarski-Linder parametrization, in
which w(a) is a linear function of a.


title: Optimality of estimators for misspecified semi-Markov models

abstract:
  Suppose we observe a geometrically ergodic semi-Markov process and have a
parametric model for the transition distribution of the embedded Markov chain,
for the conditional distribution of the inter-arrival times, or for both. The
first two models for the process are semiparametric, and the parameters can be
estimated by conditional maximum likelihood estimators. The third model for the
process is parametric, and the parameter can be estimated by an unconditional
maximum likelihood estimator. We determine heuristically the asymptotic
distributions of these estimators and show that they are asymptotically
efficient. If the parametric models are not correct, the (conditional) maximum
likelihood estimators estimate the parameter that maximizes the
Kullback--Leibler information. We show that they remain asymptotically
efficient in a nonparametric sense.


title:
Impulsive phase flare energy transport by large-scale Alfven waves and
  the electron acceleration problem

abstract:
  The impulsive phase of a solar flare marks the epoch of rapid conversion of
energy stored in the pre-flare coronal magnetic field. Hard X-ray observations
imply that a substantial fraction of flare energy released during the impulsive
phase is converted to the kinetic energy of mildly relativistic electrons
(10-100 keV). The liberation of the magnetic free energy can occur as the
coronal magnetic field reconfigures and relaxes following reconnection. We
investigate a scenario in which products of the reconfiguration - large-scale
Alfven wave pulses - transport the energy and magnetic-field changes rapidly
through the corona to the lower atmosphere. This offers two possibilities for
electron acceleration. Firstly, in a coronal plasma with beta < m_e/m_p, the
waves propagate as inertial Alfven waves. In the presence of strong spatial
gradients, these generate field-aligned electric fields that can accelerate
electrons to energies on the order of 10 keV and above, including by repeated
interactions between electrons and wavefronts. Secondly, when they reflect and
mode-convert in the chromosphere, a cascade to high wavenumbers may develop.
This will also accelerate electrons by turbulence, in a medium with a locally
high electron number density. This concept, which bridges MHD-based and
particle-based views of a flare, provides an interpretation of the
recently-observed rapid variations of the line-of-sight component of the
photospheric magnetic field across the flare impulsive phase, and offers
solutions to some perplexing flare problems, such as the flare "number problem"
of finding and resupplying sufficient electrons to explain the impulsive-phase
hard X-ray emission.


title:
Determining element abundances of [WC]-type Central Stars for probing
  stellar evolution and nucleosynthesis

abstract:
  [WC]-type CSPNs are hydrogen-deficient Central Stars of Planetary Nebulae
showing strong stellar winds and a carbon-rich chemistry. We have analyzed new
high-resolution spectra of [WC]-type CSPNs with the Potsdam Wolf-Rayet (PoWR)
non-LTE expanding atmosphere models, using upgraded model atoms and atomic
data. Previous analyses are repeated on the basis of the current models which
account for iron-line blanketing. We especially focus on determining the
chemical composition, including some trace elements like nitrogen which are of
key importance for understanding the evolutionary origin of the
hydrogen-deficient Central Stars.


title:
Statistical characteristics of the observed metal systems and problems
  of reionization

abstract:
  We analyze basic properties of about 200 metal systems observed in high
resolution spectra of 9 quasars by Boksenberg, Sargent & Rauch (2003). The
measured Doppler parameters for the hydrogen and carbon lines are found to be
different by a factor $\sim\sqrt{m_C/ m_H}$ what indicates the domination of
the thermal broadening and high degree of relaxation for majority of the
observed metal systems. The analysis of the mean separation of the metal
systems confirms that they can be located in regions with the typical proper
size $R_{cl}\sim 0.1 - 0.25h^{-1}$ Mpc what corresponds to the typical sizes of
protogalaxies with the baryonic masses $M_b\approx 10^9-10^{10}M_\odot$. The
metal abundances observed at redshifts $z=3 - 6$ within both IGM and galaxies
are found to be quite similar to each other what indicates the strong
interaction of young galaxies with the IGM and the important role of dwarf
satellites of host galaxies in such interaction. On the other hand, this metal
abundance can be considered as the integral measure of nuclear reactions within
any stars what in turn restricts the contribution of the stars to the creation
of ionizing UV background. Available now estimates of these abundances
demonstrate that attempts to explain the reionization of the Universe as a
byproduct of the process of synthesis of metals only are problematic and a
significant contribution of unobserved and/or non thermal UV sources seems to
be required.


title:
Laser-induced solid-solid phase transition in As under pressure: A
  theoretical prediction

abstract:
  In Arsenic a pressure-induced solid-solid phase transition from the A7 into
the simple cubic structure has been experimentally demonstrated [Beister et
al., Phys. Rev. B 41, 5535 (1990)]. In this paper we present calculations,
which predict that this phase transition can also be induced by an ultrashort
laser pulse in As under pressure. In addition, calculations for the
pressure-induced phase transition are presented. Using density functional
theory in the generalized gradient approximation, we found that the
pressure-induced phase transition takes place at 26.3 GPa and is accompanied by
a volume change "Delta V" = 0.5 bohr^3/atom. The laser-induced phase transition
is predicted for an applied pressure of 23.8 GPa and an absorbed laser energy
of 2.8 mRy/atom.


title: Formulae for study of LID induced diffusion in CP star model atmospheres

abstract:
  Formulae suitable for computing light-induced drift (LID) acceleration and
corresponding diffusional segregation of isotopes in CP star model atmospheres
are given.


title: A general test of the Copernican Principle

abstract:
  The recent discovery of apparent cosmic acceleration has highlighted the
depth of our ignorance of the fundamental properties of nature. It is commonly
assumed that the explanation for acceleration must come from a new form of
energy dominating the cosmos - dark energy - or a modification of Einstein's
theory of Relativity. It is often overlooked, however, that a currently viable
alternative explanation of the data is radial inhomogeneity which alters the
Hubble diagram without any acceleration. This explanation is often ignored for
two reasons: radial inhomogeneity significantly complicates analysis and
predictions, and so the full details have not been investigated; and it is a
philosophically highly controversial idea, revoking as it does the long-held
Copernican Principle. To date, there has not been a general way of determining
the validity if the Copernican Principle -- that we live at a typical position
in the universe -- significantly weakening the foundations of cosmology as a
scientific endeavour. Here we present an observational test for the Copernican
assumption which can be automatically implemented while we search for dark
energy in the coming decade. Our test is entirely independent of any model for
dark energy or theory of gravity and thereby represents a model-independent
test of the Copernican Principle.


title:
A new regularization possibility for the Boltzmann equation with soft
  potentials

abstract:
  We consider a simplified Boltzmann equation: spatially homogeneous,
two-dimensional, radially symmetric, with Grad's angular cutoff, and linearized
around its initial condition. We prove that for a sufficiently singular
velocity cross section, the solution may become instantaneously a function,
even if the initial condition is a singular measure. To our knowledge, this is
the first regularization result in the case with cutoff: all the previous
results were relying on the non-integrability of the angular cross section.
Furthermore, our result is quite surprising: the regularization occurs for
initial conditions that are not too singular, but also not too regular. The
objective of the present work is to explain that the singularity of the
velocity cross section, which is often considered as a (technical) obstacle to
regularization, seems on the contrary to help the regularization.


title: Priscilla Greenwood: Queen of Probability

abstract:
  This article contains the introduction to the special volume of Stochastics
dedicated to Priscilla Greenwood, her CV and her list of publications.


title:
F-term uplifting and moduli stabilization consistent with Kahler
  invariance

abstract:
  An important ingredient in the construction of phenomenologically viable
superstring models is the uplifting of Anti-de Sitter supersymmetric critical
points in the moduli sector to metastable Minkowski or de Sitter vacua with
broken supersymmetry. In all cases described so far, uplifting results in a
displacement of the potential minimum away from the critical point and, if the
uplifting is large, can lead to the disappearance of the minimum altogether. We
propose a variant of F-term uplifting which exactly preserves supersymmetric
critical points and shift symmetries at tree level. In spite of a direct
coupling, the moduli do not contribute to supersymmetry breaking. We analyse
the stability of the critical points in a toy one-modulus sector before and
after uplifting, and find a simple stability condition depending solely on the
amount of uplifting and not on the details of the uplifting sector. There is a
region of parameter space, corresponding to the uplifting of local AdS {\em
maxima} --or, more importantly, local minima of the Kahler function-- where the
critical points are stable for any amount of uplifting. On the other hand,
uplifting to (non- supersymmetric) Minkowski space is special in that all SUSY
critical points, that is, for all possible compactifications, become stable or
neutrally stable.


title: On weak Lie 2-algebras

abstract:
  A Lie 2-algebra is a linear category equipped with a functorial bilinear
operation satisfying skew-symmetry and Jacobi identity up to natural
transformations which themselves obey coherence laws of their own. Functors and
natural transformations between Lie 2-algebras can also be defined, yielding a
2-category. Passing to the normalized chain complex gives an equivalence of
2-categories between Lie 2-algebras and 2-term "homotopy everything" Lie
algebras; for strictly skew-symmetric Lie 2-algebras, these reduce to
$L_\infty$-algebras, by a result of Baez and Crans. Lie 2-algebras appear
naturally as infinitesimal symmetries of solutions of the Maurer--Cartan
equation in some differential graded Lie algebras and $L_\infty$-algebras. In
particular, (quasi-) Poisson manifolds, (quasi-) Lie bialgebroids and Courant
algebroids provide large classes of examples.


title:
Segregation of isotopes of heavy metals due to light-induced drift:
  results and problems

abstract:
  Atutov and Shalagin (1988) proposed light-induced drift (LID) as a physically
well understandable mechanism to explain the formation of isotopic anomalies
observed in CP stars. We generalized the theory of LID and applied it to
diffusion of heavy elements and their isotopes in quiescent atmospheres of CP
stars. Diffusional segregation of isotopes of chemical elements is described by
the equations of continuity and diffusion velocity. Computations of the
evolutionary sequences for abundances of mercury isotopes in several model
atmospheres have been made using the Fortran 90 program SMART, composed by the
authors. Results confirm predominant role of LID in separation of isotopes.


title: Q_EC values of the Superallowed beta Emitters 50Mn and 54Co

abstract:
  Using a new fast cleaning procedure to prepare isomerically pure ion samples,
we have measured the beta-decay Q_EC values of the superallowed beta-emitters
50Mn and 54Co to be 7634.48(7) keV and 8244.54(10) keV, respectively, results
which differ significantly from the previously accepted values. The corrected
Ft values derived from our results strongly support new
isospin-symmetry-breaking corrections that lead to a higher value of the
up-down quark mixing element, Vud, and improved confirmation of the unitarity
of the Cabibbo-Kobayashi-Maskawa matrix.


title: Pointwise characterizations in generalized function algebras

abstract:
  We define the algebra of Colombeau generalized functions on the space of
generalized points of {\mathbb R}^d which naturally contains the tempered
generalized functions. The subalgebra of \mathscr{S}-regular generalized
functions of this algebra is characterized by a pointwise property of the
generalized functions and their Fourier transforms. We also characterize the
equality in the sense of generalized tempered distributions for certain
elements of this algebra (namely those with so-called slow scale support) by
means of a pointwise property of their Fourier transforms. Further, we show
that (contrary to what has been claimed in the literature) for an open subset
\Omega of {\mathbb R}^d, the algebra of pointwise regular generalized functions
\dot{\mathcal G}^\infty(\Omega) equals {\mathcal G}^\infty(\Omega) and give
several characterizations of pointwise {\mathcal G}^\infty-regular generalized
functions.


title: The dark matter as a light gravitino (II)

abstract:
  We address the question of gravitino dark matter in the context of gauge
mediated supersymmetry breaking models.


title: Interpretation of quantum theory - An overview

abstract:
  Quantum Mechanics, almost 80 years after its arrival, is a well established
and experimentally not falsified theory. It has predicted and explained a whole
series of natural phenomena of a very delicate nature. But its interpretation
has not gained universal acceptance. Many scientists have considered the
conceptual framework of quantum theory to be unsatisfactory. The very
foundations of Quantum Mechanics is a matter that needs to be resolved in order
to achieve and gain a deep physical understanding of the underlying physical
procedures that constitute our world.


title: The search kinetics of a target inside the cell nucleus

abstract:
  The mean time required by a transcription factor (TF) or an enzyme to find a
target in the nucleus is of prime importance for the initialization of
transcription, gene activation or the start of DNA repair. We obtain new
estimates for the mean search time when the TF or enzyme, confined to the cell
nucleus, can switch from a one dimensional motion along the DNA and a free
Brownian regime inside the crowded nucleus. We give analytical expressions for
the mean time the particle stays bound to the DNA, $\tau_{DNA}$, and the mean
time it diffuses freely, $\tau_{free}$. Contrary to previous results but in
agreement with experimental data, we find a factor $\tau_{DNA} \approx 3.7
\tau_{free}$ for the Lac-I TF. The formula obtained for the time required to
bind to a target site is found to be coherent with observed data. We also
conclude that a higher DNA density leads to a more efficient search process.


title: Martingales and first passage times of AR(1) sequences

abstract:
  Using the martingale approach we find sufficient conditions for exponential
boundedness of first passage times over a level for ergodic first order
autoregressive sequences (AR(1)). Further, we prove a martingale identity to be
used in obtaining explicit bounds for the expectation of first passage times.


title: Time-dependent Dalitz plot analysis of B0 -> D-(+) K0 Pi+(-) decays

abstract:
  We present for the first time a measurement of the weak phase 2b+g obtained
from a time-dependent Dalitz plot analysis of B^0 -> D-(+) K0 Pi+(-) decays.
Using a sample of approximately 347*10^{6} BBbar pairs collected by the BABAR
detector at the PEP-II asymmetric-energy storage rings, we obtain
  2b+g = (83 +/- 53 +/- 20) degrees and (263 +/- 53 +/- 20) degrees assuming
the ratio r of the b -> u and b -> c decay amplitudes to be 0.3. The magnitudes
and phases for the resonances associated with the b -> c transitions are also
extracted from the fit.


title: Embedding compacta into products of curves

abstract:
  We present some results on n-dimensional compacta lying in n-dimensional
products of compacta, in particular, in products of n 1-dimensional compacta.
Most of our basic results are proven under the assumption that the compacta X
admit essential maps into the n-sphere. The results of the present paper may be
viewed as an extension of the theory developed so far by other authors.
  First, we prove that if X is an n-dimensional compactum with $H^n(X) \neq 0$
that embeds in either a product of n curves or the nth symmetric product of a
curve, then there exists an algebraically essential map of X into the n-torus.
Consequently, there exist elements $a_1,...,a_n$ in $H^1(X)$ whose cup product
is non-zero. Therefore, the rank of $H^1(X)$ is at least n, and the category of
X exceeds n. Next, we introduce some new classes of n-dimensional continua and
show that embeddability of locally connected quasi n-manifolds into products of
n curves also implies that the rank of $H^1(X)$ is at least n. It follows that
some 2-dimensional contractible polyhedra are not embeddable in products of two
curves. On the other hand, we show that any collapsible 2-dimensional
polyhedron can be embedded in a product of two trees. We answer a question
posed by Cauty proving that closed surfaces embeddable in products of two
curves can be also embedded in products of two graphs. We prove that no closed
surface, different from the 2-torus, lying in a product of two curves is a
retract of that product.


title: CLES, Code Liegeois d'Evolution Stellaire

abstract:
  Cles is an evolution code recently developed to produce stellar models
meeting the specific requirements of studies in asteroseismology. It offers the
users a lot of choices in the input physics they want in their models and its
versatility allows them to tailor the code to their needs and implement easily
new features. We describe the features implemented in the current version of
the code and the techniques used to solve the equations of stellar structure
and evolution. A brief account is given of the use of the program and of a
solar calibration realized with it.


title: Quantum phases of Fermi-Fermi mixtures in optical lattices

abstract:
  The ground state phase diagram of Fermi-Fermi mixtures in optical lattices is
analyzed as a function of interaction strength, population imbalance, filling
fraction and tunneling parameters. It is shown that population imbalanced
Fermi-Fermi mixtures reduce to strongly interacting Bose-Fermi mixtures in the
molecular limit, in sharp contrast to homogeneous or harmonically trapped
systems where the resulting Bose-Fermi mixture is weakly interacting.
Furthermore, insulating phases are found in optical lattices of Fermi-Fermi
mixtures in addition to the standard phase-separated or coexisting
superfluid/excess fermion phases found in homogeneous systems. The insulating
states can be a molecular Bose-Mott insulator (BMI), a Fermi-Pauli insulator
(FPI), a phase-separated BMI/FPI mixture or a Bose-Fermi checkerboard (BFC).


title: Monotone versions of $\delta$-normality

abstract:
  We continue the study of properties related to monotone countable
paracompactness, investigating various monotone versions of $\delta$-normality.
We factorize monotone normality and stratifiability in terms of these weaker
properties.


title: The Liege Oscillation Code

abstract:
  The Liege Oscillation code can be used as a stand-alone program or as a
library of subroutines that the user calls from a Fortran main program of his
own to compute radial and non-radial adiabatic oscillations of stellar models.
We describe the variables and the equations used by the program and the methods
used to solve them. A brief account is given of the use and the output of the
program.


title: Extragalactic Objects and Next Generation Interferometers

abstract:
  The most obvious extragalactic targets for optical/infrared interferometers
are Active Galactic Nuclei. In this document, I try to overview other topics
that could be of interest to studies of galaxies and whether they could be
adequate for a next generation interferometer. The very high spatial resolution
would be profitable for extragalactic supernovae, globular clusters, star
forming regions, gravitational lenses and some stellar studies in very close
galaxies. However, sensitivity is the main concern since the interesting
magnitude limit would have to be of the order of 25 or more for these studies
not to remain marginal.


title: On cyclic fixed points of spectra

abstract:
  For a finite p-group G and a bounded below G-spectrum X of finite type mod p,
the G-equivariant Segal conjecture for X asserts that the canonical map X^G -->
X^{hG} is a p-adic equivalence. Let C_{p^n} be the cyclic group of order p^n.
We show that if the C_p Segal conjecture holds for a C_{p^n} spectrum X, as
well as for each of its C_{p^e} geometric fixed points for 0 < e < n, then then
C_{p^n} Segal conjecture holds for X. Similar results hold for weaker forms of
the Segal conjecture, asking only that the canonical map induces an equivalence
in sufficiently high degrees, on homotopy groups with suitable finite
coefficients.


title: A note on restricted X-ray transforms

abstract:
  We show how the techniques introduces by Christ can be employed to derive
endpoint $L^p-L^q$ bounds for the X-ray transform associated to the line
complex generated by the curve $t\to(t,t^2,...,t^{d-1}).$ Almost-sharp Lorentz
space estimates are produced as well.


title: The Kadets 1/4 theorem for polynomials

abstract:
  We determine the maximal angular perturbation of the (n+1)th roots of unity
permissible in the Marcinkiewicz-Zygmund theorem on L^p means of polynomials of
degree at most n. For p=2, the result is an analogue of the Kadets 1/4 theorem
on perturbation of Riesz bases of holomorphic exponentials.


title:
Gravity modes and mixed modes as probes of stellar cores in
  main-sequence stars: from solar-like to beta Cep stars

abstract:
  We investigate how the frequencies of gravity modes depend on the detailed
properties of the chemical composition gradient that develops near the core of
main-sequence stars and, therefore, on the transport processes that are able to
modify the \mu profile in the central regions. We show that in main-sequence
models, similarly to the case of white dwarfs, the periods of high-order
gravity modes are accurately described by a uniform period spacing superposed
to an oscillatory component. The periodicity and amplitude of such component
are related, respectively, to the location and sharpness of the \mu gradient.
We briefly discuss and interpret, by means of this simple approximation, the
effect of turbulent mixing near the core on the periods of both high-order and
low-order g modes, as well as of modes of mixed pressure-gravity character.


title: Revised element abundances for WC-type central stars

abstract:
  According to previous spectral analyses of Wolf-Rayet type central stars,
late [WC] subtypes show systematically higher carbon-to-helium abundance ratios
than early [WC] subtypes. If this were true, it would rule out that these stars
form an evolutionary sequence. However, due to the different parameter domains
and diagnostic lines, one might suspect systematic errors being the source of
this discrepancy. In an ongoing project we are therefore checking the [WC]
analyses by means of the last generation of non-LTE models for expanding
stellar atmospheres which account for line-blanketing and wind clumping. So
far, the abundance discrepancy is not resolved. Further element abundances (H,
N, Fe) are determined and compared with evolutionary predictions.


title: The effect of turbulent mixing on the g-mode spectrum of MS stars

abstract:
  The understanding of transport processes inside the stars is one of the main
goals of asteroseismology. Chemical turbulent mixing can affect the internal
distribution of \mu near the energy generating core, having an effect on the
evolutionary tracks similar to that of overshooting. This mixing leads to a
smoother chemical composition profile near the edge of the convective core,
which is reflected in the behavior of the buoyancy frequency and, therefore, in
the frequencies of gravity modes. We describe the effects of convective
overshooting and turbulent mixing on the frequencies of gravity modes in B-type
main sequence stars. In particular, the cases of p-g mixed modes in beta Cep
stars and high-order modes in SPBs are considered.


title:
Discovery of a wide companion near the deuterium burning mass limit in
  the Upper Scorpius association

abstract:
  We present the discovery of a companion near the deuterium burning mass limit
located at a very wide distance, at an angular separation of 4.6+/-0.1 arcsec
(projected distance of ~ 670 AU) from UScoCTIO108, a brown dwarf of the very
young Upper Scorpius association. Optical and near-infrared photometry and
spectroscopy confirm the cool nature of both objects, with spectral types of M7
and M9.5, respectively, and that they are bona fide members of the association,
showing low gravity and features of youth. Their masses, estimated from the
comparison of their bolometric luminosities and theoretical models for the age
range of the association, are 60+/-20 and 14^{+2}_{-8} MJup, respectively. The
existence of this object around a brown dwarf at this wide orbit suggests that
the companion is unlikely to have formed in a disk based on current planet
formation models. Because this system is rather weakly bound, they did not
probably form through dynamical ejection of stellar embryos.


title: Magnetized CMB observables: a dedicated numerical approach

abstract:
  Large-scale magnetic fields affect the scalar modes of the geometry whose
ultimate effect is to determine the anisotropies of the Cosmic Microwave
Background (CMB in what follows). For the first time, a consistent numerical
approach to the magnetized CMB anisotropies is pursued with the aim of
assessing the angular power spectra of temperature and polarization when the
scalar modes of the geometry and a stochastic background of inhomogeneous
magnetic fields are simultaneously present in the plasma. The effects related
to the magnetized nature of the plasma are taken into account both at the level
of the dynamical equations and at the level of the initial conditions of the
Einstein-Boltzmann hierarchy. The temperature and polarization observables are
exploited to infer the peculiar signatures of a pre-equality magnetic field.
Using the extrapolated best fit to the three year WMAP data the increase and
distortions of the first seven peaks in the TT autocorrelations are monitored
for different values of the regularized magnetic field intensity and for the
physical range of spectral indices. Similar analyses are also conducted for the
first few anticorrelation (and corrrelation) peaks of the TE power spectra.
Possible interesting degeneracies and stimulating perspectives are pointed out
and explored.


title: On the cohomology rings of holomorphically fillable manifolds

abstract:
  An odd-dimensional differentiable manifold is called \emph{holomorphically
fillable} if it is diffeomorphic to the boundary of a compact strongly
pseudoconvex complex manifold, \emph{Stein fillable} if this last manifold may
be chosen to be Stein and \emph{Milnor fillable} if it is diffeomorphic to the
abstract boundary of an isolated singularity of normal complex analytic space.
We show that the homotopical dimension of a manifold-with-boundary of dimension
at least 4 restricts the cohomology ring (with any coefficients) of its
boundary. This gives restrictions on the cohomology rings of Stein fillable
manifolds, on the dimension of the exceptional locus of any resolution of a
given isolated singularity, and on the topology of smoothable singularities. We
give also new proofs of structure theorems of Durfee & Hain and Bungart about
the cohomology rings of Milnor fillable and respectively holomorphically
fillable manifolds. The various structure theorems presented in this paper
imply that in dimension at least 5, the classes of Stein fillable, Milnor
fillable and holomorphically fillable manifolds are pairwise different.


title: Smart expansion and fast calibration for jump diffusion

abstract:
  Using Malliavin calculus techniques, we derive an analytical formula for the
price of European options, for any model including local volatility and Poisson
jump process. We show that the accuracy of the formula depends on the
smoothness of the payoff function. Our approach relies on an asymptotic
expansion related to small diffusion and small jump frequency/size. Our formula
has excellent accuracy (the error on implied Black-Scholes volatilities for
call option is smaller than 2 bp for various strikes and maturities).
Additionally, model calibration becomes very rapid.


title: Lacunarity and cyclic vectors for the Backward Shift

abstract:
  This article gives a description of invariant subspaces for the backward
shift generated by vector valued lacunary series and by a class of lacunary
power series in $H^2(\mathbb{D}, X)$, (where $X$ is an Hilbert space). In
particular, we show that these series $f$ in $H^2(\mathbb{D}, X)$ are cyclic
vectors if and only if the queue of Taylor coefficients $\{\hat{f}(k)$, $k>N\}$
generates the whole space $X$. Analogues of this result are obtained for some
functions whose spectrum is a finite union of lacunary sequences and in the
polydisc. In the scalar case $H^2$, we give a criterion on the Fourier spectrum
of the function to have cyclicity for any power of the backward shift.


title: UV Radiation Fields Produced by Young Embedded Star Clusters

abstract:
  A large fraction of stars form within young embedded clusters, and these
environments produce a substantial ultraviolet (UV) background radiation field,
which can provide feedback on the star formation process. To assess the
possible effects of young stellar clusters on the formation of their
constituent stars and planets, this paper constructs the expected radiation
fields produced by these clusters. We include both the observed distribution of
cluster sizes $N$ in the solar neighborhood and an extended distribution that
includes clusters with larger $N$. The paper presents distributions of the FUV
and EUV luminosities for clusters with given stellar membership $N$,
distributions of FUV and EUV luminosity convolved over the expected
distribution of cluster sizes $N$, and the corresponding distributions of FUV
and EUV fluxes. These flux distributions are calculated both with and without
the effects of extinction. Finally, we consider the effects of variations in
the stellar initial mass function on these radiation fields. Taken together,
these results specify the distributions of radiation environments that forming
solar systems are expected to experience.


title: Teaching statistical physics by thinking about models and algorithms

abstract:
  We discuss several ways of illustrating fundamental concepts in statistical
and thermal physics by considering various models and algorithms. We emphasize
the importance of replacing students' incomplete mental images by models that
are physically accurate. In some cases it is sufficient to discuss the results
of an algorithm or the behavior of a model rather than having students write a
program.


title: Quantization of the Myers-Pospelov model: a progress report

abstract:
  The Myers-Pospelov (MP) model is an effective field theory, including
dimension five operators, which describes the phenomenology of active Lorentz
invariance violation produced by a preferred reference frame. We concentrate
here in the case of the modified electrodynamics. The point of view taken in
this work is that the Lorentz violating part of the action in the MP model,
which includes higher order time derivative (HOTD) operators, is to be
considered as a perturbation over the dynamics described by standard
Electrodynamics, particularly in the quantum case. In order to cope with the
challenges posed by HOTD theories it will be necessary to deal with a modified
perturbation scheme which is well described in the literature. We apply such
methods to this specific model providing a quantization of the free sector of
the theory. The calculation of interacting processes, together with radiative
corrections, is beyond the scope of the present article.


title:
Combinatorial rigidity for some infinitely renormalizable unicritical
  polynomials

abstract:
  We prove combinatorial rigidity of infinitely renormalizable unicritical
polynomials, P_c :z \mapsto z^d+c, with complex c, under the a priori bounds
and a certain "combinatorial condition". This implies the local connectivity of
the connectedness loci (the Mandelbrot set when d = 2) at the corresponding
parameters.


title: Gluon Scattering in Deformed N=4 SYM

abstract:
  We consider gluon and gluino scattering amplitudes in large N beta-deformed
N=4 SYM with real beta. A direct inspection of the planar diagrams shows that
the scattering amplitudes to all orders in perturbation theory are the same as
in the undeformed N=4 SYM theory. Using the dual sigma-model description, we
find the same equality at strong coupling to all orders in the sigma-model loop
expansion. Finally, we show that the same analysis holds for gluon scattering
amplitudes in a three-parameter deformation of planar N=4 SYM that breaks all
the supersymmetry.


title: Semiclassical statistical mechanics' tools for deformed algebras

abstract:
  In order to enlarge the present arsenal of semiclassical toools we explicitly
obtain here the Husimi distributions and Wehrl entropy within the context of
deformed algebras built up on the basis of a new family of q-deformed coherent
states, those of Quesne [J. Phys. A 35, 9213 (2002)]. We introduce also a
generalization of the Wehrl entropy constructed with escort distributions. The
two generalizations are investigated with emphasis on i) their behavior as a
function of temperature and ii) the results obtained when the
deformation-parameter tends to unity.


title: Measurement of the Decay B- --> D*0 e- nubar

abstract:
  Using 226 million BBbar events recorded on the Upsilon(4S) resonance with the
BABAR detector at the SLAC e+e- PEPII storage rings, we reconstruct B- -> D*0
e- nubar decays using the decay chain D*0 -> D0 pi0 and D0 -> K pi. From the
dependence of their differential rate on w, the dot product of the
four-velocities of B and D*0, and using the form factor description by Caprini
et al. with the parameters F(1) and rho_A1^2, we obtain the results rho_A1^2 =
1.16 +- 0.06 +- 0.08, F(1)|V_cb| = (35.9 +- 0.6 +- 1.4) 10^-3, and BF(B- -> D*0
e- nubar) = (5.56 +- 0.08 +- 0.41)%.


title: Modelling background intensity in Affymetrix Genechips

abstract:
  DNA microarrays are devices that are able, in principle, to detect and
quantify the presence of specific nucleic acid sequences in complex biological
mixtures. The measurement consists in detecting fluorescence signals from
several spots on the microarray surface onto which different probe sequences
are grafted. One of the problems of the data analysis is that the signal
contains a noisy background component due to non-specific binding. This paper
presents a physical model for background estimation in Affymetrix Genechips. It
combines two different approaches. The first is based on the sequence
composition, specifically its sequence dependent hybridization affinity. The
second is based on the strong correlation of intensities from locations which
are the physical neighbors of a specific spot on the chip. Both effects are
incorporated in a background functional which contains 24 free parameters,
fixed by minimization on a training data set. In all data analyzed the sequence
specific parameters, obtained by minimization, are found to strongly correlate
with empirically determined stacking free energies for RNA/DNA hybridization in
solution. Moreover, there is an overall agreement with experimental background
data and we show that the physics-based model proposed in this paper performs
on average better than purely statistical approaches for background
calculations. The model thus provides an interesting alternative method for
background subtraction schemes in Affymetrix Genechips.

categories: q-bio.BM physics.bio-ph physics.chem-ph physics.data-an q-bio.QM