title:
The dramatic size evolution of elliptical galaxies and the quasar
  feedback

abstract:
  Observations have evidenced that passively evolving massive galaxies at high
redshift are much more compact than local galaxies with the same stellar mass.
We argue that the observed strong evolution in size is directly related to the
quasar feedback, which removes huge amounts of cold gas from the central
regions in a Salpeter time, inducing an expansion of the stellar distribution.
The new equilibrium configuration, with a size increased by a factor >~ 3, is
attained after ~ 40 dynamical times, corresponding to ~ 2 Gyr. This means that
massive galaxies observed at z >~ 1 will settle on the Fundamental Plane by z ~
0.8-1. In less massive galaxies (M_star <~ 2 10^10 M_sun), the nuclear feedback
is subdominant, and the mass loss is mainly due to stellar winds. In this case,
the mass loss timescale is longer than the dynamical time and results in
adiabatic expansion that may increase the effective radius by a factor of up to
~ 2 in 10 Gyr, although a growth by a factor of ~ 1.6 occurs within the first
0.5 Gyr. Since observations are focused on relatively old galaxies, with ages
>~ 1 Gyr, the evolution for smaller galaxies is more difficult to perceive.
Significant evolution of velocity dispersion is predicted for both small and
large galaxies.


title: Multi-path entanglement of two photons

abstract:
  We present a novel optical device based on an integrated system of
micro-lenses and single mode optical fibers. It allows to collect and direct
into many modes two photons generated by spontaneous parametric down
conversion. By this device multiqubit entangled states and/or multilevel
qu-$d$it states of two photons, encoded in the longitudinal momentum degree of
freedom, are created. The multi-path photon entanglement realized by this
device is expected to find important applications in modern quantum information
technology.


title: On-the-Fly Coding to Enable Full Reliability Without Retransmission

abstract:
  This paper proposes a new reliability algorithm specifically useful when
retransmission is either problematic or not possible. In case of multimedia or
multicast communications and in the context of the Delay Tolerant Networking
(DTN), the classical retransmission schemes can be counterproductive in terms
of data transfer performance or not possible when the acknowledgment path is
not always available. Indeed, over long delay links, packets retransmission has
a meaning of cost and must be minimized.In this paper, we detail a novel
reliability mechanism with an implicit acknowledgment strategy that could be
used either within these new DTN proposals, for multimedia traffic or in the
context of multicast transport protocols. This proposal is based on a new
on-the-fly erasure coding concept specifically designed to operate efficient
reliable transfer over bi-directional links. This proposal, named Tetrys,
allows to unify a full reliability with an error correction scheme. In this
paper, we model the performance of this proposal and demonstrate with a
prototype, that we can achieve a full reliability without acknowledgment path
confirmation. Indeed, the main findings are that Tetrys is not sensitive to the
loss of acknowledgments while ensuring a faster data availability to the
application compared to other traditional acknowledgment schemes. Finally, we
pave the first step of the integration of such algorithm inside a congestion
controlled protocol.


title: A Generic Top-Down Dynamic-Programming Approach to Prefix-Free Coding

abstract:
  Given a probability distribution over a set of n words to be transmitted, the
Huffman Coding problem is to find a minimal-cost prefix free code for
transmitting those words. The basic Huffman coding problem can be solved in O(n
log n) time but variations are more difficult. One of the standard techniques
for solving these variations utilizes a top-down dynamic programming approach.
In this paper we show that this approach is amenable to dynamic programming
speedup techniques, permitting a speedup of an order of magnitude for many
algorithms in the literature for such variations as mixed radix, reserved
length and one-ended coding. These speedups are immediate implications of a
general structural property that permits batching together the calculation of
many DP entries.


title: Conductance of disordered graphene superlattice

abstract:
  We study the conductance of disordered graphene superlattices with
short-range structural correlations. The system consists of electron- and
hole-doped graphenes of various thicknesses, which fluctuate randomly around
their mean value. The effect of the randomness on the probability of
transmission through the system of various sizes is studied. We show that in a
disordered superlattice the quasiparticle that approaches the barrier interface
almost perpendicularly transmits through the system. The conductivity of the
finite-size system is computed and shown that the conductance vanishes when the
sample size becomes very large, whereas for some specific structures the
conductance tends to a nonzero value in the thermodynamics limit.


title:
Three examples of the relation between rigid-analytic and algebraic
  deformation parameters

abstract:
  We consider three examples of families of curves over a non-archimedean
valued field which admit a non-trivial group action. These equivariant
deformation spaces can be described by algebraic parameters (in the equation of
the curve), or by rigid-analytic parameters (in the Schottky group of the
curve). We study the relation between these parameters as rigid-analytic
self-maps of the disk.


title: The Minkowski problem for the torsional rigidity

abstract:
  We prove the existence and uniqueness up to translations of the solution to a
Minkowski type problem for the torsional rigidity in the class of open bounded
convex subsets of the $n$-dimensional Euclidean space. For the existence part
we apply the variational method introduced by Jerison for analogous problems
concerning other variational functionals. Uniqueness follows from the
Brunn--Minkowski inequality for the torsional rigidity and corresponding
equality conditions.


title: Search for low Energy solar Axions with CAST

abstract:
  We have started the development of a detector system, sensitive to single
photons in the eV energy range, to be suitably coupled to one of the CAST
magnet ports. This system should open to CAST a window on possible detection of
low energy Axion Like Particles emitted by the sun. Preliminary tests have
involved a cooled photomultiplier tube coupled to the CAST magnet via a
Galileian telescope and a switched 40 m long optical fiber. This system has
reached the limit background level of the detector alone in ideal conditions,
and two solar tracking runs have been performed with it at CAST. Such a
measurement has never been done before with an axion helioscope. We will
present results from these runs and briefly discuss future detector
developments.


title:
Achieving compositionality of the stable model semantics for Smodels
  programs

abstract:
  In this paper, a Gaifman-Shapiro-style module architecture is tailored to the
case of Smodels programs under the stable model semantics. The composition of
Smodels program modules is suitably limited by module conditions which ensure
the compatibility of the module system with stable models. Hence the semantics
of an entire Smodels program depends directly on stable models assigned to its
modules. This result is formalized as a module theorem which truly strengthens
Lifschitz and Turner's splitting-set theorem for the class of Smodels programs.
To streamline generalizations in the future, the module theorem is first proved
for normal programs and then extended to cover Smodels programs using a
translation from the latter class of programs to the former class. Moreover,
the respective notion of module-level equivalence, namely modular equivalence,
is shown to be a proper congruence relation: it is preserved under
substitutions of modules that are modularly equivalent. Principles for program
decomposition are also addressed. The strongly connected components of the
respective dependency graph can be exploited in order to extract a module
structure when there is no explicit a priori knowledge about the modules of a
program. The paper includes a practical demonstration of tools that have been
developed for automated (de)composition of Smodels programs.
  To appear in Theory and Practice of Logic Programming.


title:
Liverpool Telescope Optical Photometry Following the 2006 Outburst of RS
  Ophiuchi

abstract:
  We present a preliminary report on the broadband optical photometry of the
2006 outburst of the recurrent nova RS Ophiuchi. These data were obtained using
the robotic 2m Liverpool Telescope and cover the outburst from day 27 through
day 548.


title:
Current-pulse-induced magnetic switching in standard and nonstandard
  spin-valves

abstract:
  Magnetization switching due to a current-pulse in symmetric and asymmetric
spin valves is studied theoretically within the macrospin model. The switching
process and the corresponding switching parameters are shown to depend
significantly on the pulse duration and also on the interplay of the torques
due to spin transfer and external magnetic field. This interplay leads to
peculiar features in the corresponding phase diagram. These features in
standard spin valves, where the spin transfer torque stabilizes one of the
magnetic configurations (either parallel or antiparallel) and destabilizes the
opposite one, differ from those in nonstandard (asymmetric) spin valves, where
both collinear configurations are stable for one current orientation and
unstable for the opposite one. Following this we propose a scheme of ultrafast
current-induced switching in nonstandard spin valves, based on a sequence of
two current pulses.


title: A new non-perturbative approach to Quantum Brownian Motion

abstract:
  Starting from the Caldeira-Leggett (CL) model, we derive the equation
describing the Quantum Brownian motion, which has been originally proposed by
Dekker purely from phenomenological basis containing extra anomalous diffusion
terms. Explicit analytical expressions for the temperature dependence of the
diffusion constants are derived. At high temperatures, additional momentum
diffusion terms are suppressed and classical Langivin equation can be recovered
and at the same time positivity of the density matrix(DM) is satisfied. At low
temperatures, the diffusion constants have a finite positive value, however,
below a certain critical temperature, the Master Equation(ME) does not satisfy
the positivity condition as proposed by Dekker.


title: Bow wave from ultra-intense electromagnetic pulses in plasmas

abstract:
  We show a new effect of the bow wave excitation by an intense short laser
pulse propagating in underdense plasma. Due to spreading of the laser pulse
energy in transverse direction, the bow wave causes a large-scale transverse
modulation of the electron density. This can significantly increase the
electric potential of the wake wave since the wake wave is generated in the
region much wider than the laser pulse waist.

categories: physics.plasm-ph physics.comp-ph physics.flu-dyn physics.space-ph


title:
English translation of chapter 9 of the book "Adams spectral sequence
  and stable homotopy groups of spheres" by Jijkun Lin (In Chinese)(Sciences
  Press, Beijing 2007)

abstract:
  This paper is an English translation of chapter nine of the book "Adams
spectral sequence and stable homotopy groups of spheres" by Jinkun Lin (in
Chinese)(Sciences Press, Beijing 2007). In this paper, a sequence of new
indecomposable families in the stable homotopy groups of spheres such as
h_0h_n,h_nb_n,h_0h_nh_m,h_0(h_mb_{n-1}-b_{m-1}h_n) families was detected. The
proof of all the detections was stated in this paper in based on several
published papers by the author.


title:
Testing evolutionary tracks of Pre-Main Sequence stars: the case of
  HD113449

abstract:
  Evolutionary tracks are of key importance for the understanding of star
formation. Unfortunately, tracks published by various groups differ so that it
is fundamental to have observational tests. In order to do this, we intend to
measure the masses of the two components of the Pre-Main Sequence binary
HD113449 by combining radial velocity measurements taken with HARPS, with
infrared interferometric data using AMBER on the VLTI. The spectroscopic orbit
that has already been determined, combined with the first AMBER measurement,
allows us to obtain a very first estimation of the inclination of the binary
system and from this the masses of the two stars. More AMBER measurements of HD
113449 are needed to improve the precision on the masses: in the ESO period P82
two new measurements are scheduled.


title:
A New Spectroscopic and Photometric Analysis of the Transiting Planet
  Systems TrES-3 and TrES-4

abstract:
  We report new spectroscopic and photometric observations of the parent stars
of the recently discovered transiting planets TrES-3 and TrES-4. A detailed
abundance analysis based on high-resolution spectra yields [Fe/H] $= -0.19\pm
0.08$, $T_\mathrm{eff} = 5650\pm 75$ K, and $\log g = 4.4\pm 0.1$ for TrES-3,
and [Fe/H] $= +0.14\pm 0.09$, $T_\mathrm{eff} = 6200\pm 75$ K, and $\log g =
4.0\pm0.1$ for TrES-4. The accuracy of the effective temperatures is supported
by a number of independent consistency checks. The spectroscopic orbital
solution for TrES-3 is improved with our new radial-velocity measurements of
that system, as are the light-curve parameters for both systems based on newly
acquired photometry for TrES-3 and a reanalysis of existing photometry for
TrES-4. We have redetermined the stellar parameters taking advantage of the
strong constraint provided by the light curves in the form of the normalized
separation $a/R_\star$ (related to the stellar density) in conjunction with our
new temperatures and metallicities. The masses and radii we derive are
$M_\star=0.928_{-0.048}^{+0.028} M_{\sun}$,$R_\star = 0.829_{-0.022}^{+0.015}
R_{\sun}$, and $M_\star = 1.404_{-0.134}^{+0.066} M_{\sun}$,
$R_\star=1.846_{-0.087}^{+0.096} R_{\sun}$ for TrES-3 and TrES-4, respectively.
With these revised stellar parameters we obtain improved values for the
planetary masses and radii. We find $M_p = 1.910_{-0.080}^{+0.075}
M_\mathrm{Jup}$, $R_p=1.336_{-0.036}^{+0.031} R_\mathrm{Jup}$ for TrES-3, and
$M_p=0.925 \pm 0.082 M_\mathrm{Jup}$, $R_p=1.783_{-0.086}^{+0.093}
R_\mathrm{Jup}$ for TrES-4. We confirm TrES-4 as the planet with the largest
radius among the currently known transiting hot Jupiters.


title: Extragalactic Classical Nova Surveys

abstract:
  We are currently involved in a multifaceted campaign to study extragalactic
classical novae in the Local Group and beyond. Here we report on-going results
from the exploitation of the POINT-AGAPE M31 dataset; initial results from our
Local Group imaging, and spectroscopic CNe follow-up campaign and introduce the
Liverpool Extragalactic Nova Survey.


title:
Noether symmetric $f(R)$ quantum cosmology and its classical
  correlations

abstract:
  We quantize a flat FRW cosmology in the context of the $f(R)$ gravity by
Noether symmetry approach. We explicitly calculate the form of $f(R)$ for which
such symmetries exist. It is shown that the existence of a Noether symmetry
yields a general solution of the Wheeler-DeWitt equation where can be expressed
as a superposition of states of the form $e^{iS}$. In terms of Hartle
criterion, this type of wave function exhibits classical correlations, i.e. the
emergent of classical universe is expected due to the oscillating behavior of
the solutions of Wheeler-DeWitt equation. According to this interpretation we
also provide the Noether symmetric classical solutions of our $f(R)$
cosmological model.


title:
Hubble Space Telescope Imaging of the Expanding Nebular Remnant of the
  2006 Outburst of RS Ophiuchi

abstract:
  We report {\it Hubble Space Telescope} imaging obtained 155 days and 449 days
after the 2006 outburst of RS Ophiuchi. Both epochs show evidence of extended
emission, consistent with that seen in earlier radio observations, and a
maximum expansion rate of $3200\pm300$ km s$^{-1}$ (in the plane of the sky).
The extended structure is consistent with the remnant having a bipolar
morphology with an inclination similar to that determined for the binary.


title: Swift Observations of Shock Evolution in RS Ophiuchi

abstract:
  Our \textit{Swift} observations of RS Oph form an unprecedented X-ray dataset
to undertake investigations of both the central source and the interaction of
the outburst ejecta with the circumstellar environment. Over the first month,
the XRT data are dominated by emission from rapidly evolving shocks. We discuss
the differences in derived parameters from those found for \textit{RXTE} at
early times and the evolution of the X-ray emission to much later times. It is
apparent that at late times several emission components are present. We find no
strong evidence of the proposed shock break-out in our data.


title: Which BPS Baryons Minimize Volume?

abstract:
  A BPS 3-cycle in a Sasaki-Einstein 5-manifold in general does not minimize
volume in its homology class, as we illustrate with several examples of
non-minimal volume BPS cycles on the 5-manifolds Y(p,q). Instead they minimize
the energy of a wrapping D-brane, extremizing a generalized calibration. We
present this generalized calibration and demonstrate that it reproduces both
the Born-Infeld and the Wess-Zumino parts of the D3-brane energy.


title: Ultra-fast spin dynamics: the effect of colored noise

abstract:
  Recent experimental results have pushed the limits of magnetization dynamics
to pico- and femtosecond timescales. This ultra-fast spin dynamics occurs in
extreme conditions of strong and rapidly varying fields and high temperatures.
This situation requires new description of magnetization dynamics, even on a
phenomenological level of the atomistic Landau-Lifshitz-Gilbert equation,
taking into account that the correlation time for electron system could be of
the order of the inverse characteristic spin frequency. For this case we
introduce the thermodynamically correct phenomenological approach for spin
dynamics based on the Landau-Lifshitz-Miyasaki-Seki equation. The influence of
the noise correlation time on longitudinal and transverse magnetization
relaxation is investigated. We also demonstrate the effect of the noise
correlation time on demagnetisation rate of different materials during
laser-induced dynamics.


title: Photons from anisotropic Quark-Gluon-Plasma

abstract:
  We calculate medium photons due to Compton and annihilation processes in an
anisotropic media. The effects of time-dependent momentum-space anisotropy of
{\em Quark-Gluon-Plasma} (QGP) on the medium photon production are discussed.
Such an anisotropy can results from the initial rapid longitudinal expansion of
the matter, created in relativistic heavy ion collisions. A phenomenological
model for the time-dependence of the parton hard momentum scale,
$p_{hard}(\tau)$, and anisotropy parameter, $\xi(\tau)$, has been used to
describe the plasma space-time evolution. We find significant dependency of
photon yield on the isotropization time ($\tau_{iso}$). It is shown that the
introduction of early time momentum-space anisotropy can enhance the photon
production by a factor of $10 (1.5)$ (in the central rapidity region) for {\em
free streaming} ({\em collisionally-broadened}) {\em interpolating} model if we
assume fixed initial condition. On the other hand, enforcing the fixed final
multiplicity significantly reduces the enhancement of medium photon production.


title: The sub-Jupiter mass transiting exoplanet WASP-11b

abstract:
  We report the discovery of a sub-Jupiter mass exoplanet transiting a
magnitude V=11.7 host star 1SWASP J030928.54+304024.7. A simultaneous fit to
the transit photometry and radial-velocity measurements yield a planet mass
M_p=0.53+-0.07M_J, radius R_p=0.91^{+0.06}_{-0.03}R_J and an orbital period of
3.722465^{+0.000006}_{-0.000008} days. The host star is of spectral type K3V,
with a spectral analysis yielding an effective temperature of 4800+-100K and
log g=4.45+-0.2. It is amongst the smallest, least massive and lowest
luminosity stars known to harbour a transiting exoplanet. WASP-11b is the third
least strongly irradiated transiting exoplanet discovered to date, experiencing
an incident flux F_p=1.9x10^8 erg s^{-1} cm^{-2} and having an equilibrium
temperature T_eq=960+-70K.


title: Higher Dimensional Operators in the MSSM

abstract:
  The origin and the implications of higher dimensional effective operators in
4-dimensional theories are discussed in non-supersymmetric and supersymmetric
cases. Particular attention is paid to the role of general,
derivative-dependent field redefinitions which one can employ to obtain a
simpler form of the effective Lagrangian. An application is provided for the
Minimal Supersymmetric Standard Model extended with dimension-five R-parity
conserving operators, to identify the minimal irreducible set of such operators
after supersymmetry breaking. Among the physical consequences of this set of
operators are the presence of corrections to the MSSM Higgs sector and the
generation of "wrong"-Higgs Yukawa couplings and fermion-fermion-scalar-scalar
interactions. These couplings have implications for supersymmetry searches at
the LHC.


title:
Population growth and persistence in a heterogeneous environment: the
  role of diffusion and advection

abstract:
  The spatio-temporal dynamics of a population present one of the most
fascinating aspects and challenges for ecological modelling. In this article we
review some simple mathematical models, based on one dimensional
reaction-diffusion-advection equations, for the growth of a population on a
heterogeneous habitat. Considering a number of models of increasing complexity
we investigate the often contrary roles of advection and diffusion for the
persistence of the population. When it is possible we demonstrate basic
mathematical techniques and give the critical conditions providing the survival
of a population, in simple systems and in more complex resource-consumer models
which describe the dynamics of phytoplankton in a water column.


title:
Range separation combined with the Overhauser model: Application to the
  H$_2$ molecule along the dissociation curve

abstract:
  The combination of density-functional theory with other approaches to the
many-electron problem through the separation of the electron-electron
interaction into a short-range and a long-range contribution (range separation)
is a successful strategy, which is raising more and more interest in recent
years. We focus here on a range-separated method in which only the short-range
correlation energy needs to be approximated, and we model it within the
"extended Overhauser approach". We consider the paradigmatic case of the H$_2$
molecule along the dissociation curve, finding encouraging results. By means of
very accurate variational wavefunctions, we also study how the effective
electron-electron interaction appearing in the Overhauser model should be in
order to yield the exact correlation energy for standard Kohn-Sham density
functional theory.


title: Random block matrices and matrix orthogonal polynomials

abstract:
  In this paper we consider random block matrices, which generalize the general
beta ensembles, which were recently investigated by Dumitriu and Edelmann
(2002, 2005). We demonstrate that the eigenvalues of these random matrices can
be uniformly approximated by roots of matrix orthogonal polynomials which were
investigated independently from the random matrix literature. As a consequence
we derive the asymptotic spectral distribution of these matrices. The limit
distribution has a density, which can be represented as the trace of an
integral of densities of matrix measures corresponding to the Chebyshev matrix
polynomials of the first kind. Our results establish a new relation between the
theory of random block matrices and the field of matrix orthogonal polynomials,
which have not been explored so far in the literature.


title: Dynamics of a bubble formed in double stranded DNA

abstract:
  We study the fluctuational dynamics of a tagged base-pair in double stranded
DNA. We calculate the drift force which acts on the tagged base-pair using a
potential model that describes interactions at base pairs level and use it to
construct a Fokker-Planck equation.The calculated displacement autocorrelation
function is found to be in very good agreement with the experimental result of
Altan-Bonnet {\it et. al.} Phys. Rev. Lett. {\bf 90}, 138101 (2003) over the
entire time range of measurement. We calculate the most probable displacements
which predominately contribute to the autocorrelation function and the
half-time history of these displacements.


title: Boundary S-matrix in a (2,0) theory of AdS_{3} Supergravity

abstract:
  We will discuss two inequivalent generalizations of the standard (2,0)
supergravity action gr-qc/9501018 to include gravitational Chern-Simons term.
One is in the first order formalism where we treat \omega_{M}^{ab} as
independent and the other is in the second order formalism where
\omega_{M}^{ab} is determined in terms of other fields via a standard
constraint equation. The two theories have different equations of motion and
the solutions to the equations of motion of the first order theory spans only a
subset of those of the second order theory. We will be interested in computing
the boundary S-matrix, describing correlation functions in a dual conformal
field theory, in this sector and hence we use the equations of motion coming
out of the first order theory. We restrict ourselves to the gauge+fermionic
sector of the theory to compute the boundary S-matrix. We will also look at the
effect of higher derivative terms on the boundary S-matrix obtained using the
standard supergravity action.


title:
Covariant and self consistent vertex corrections for pions and isobars
  in nuclear matter

abstract:
  We evaluate the pion and isobar propagators in cold nuclear matter self
consistently applying a covariant form of the isobar-hole model. Migdal's
vertex correction effects are considered systematically in the absence of
phenomenological soft form factors. Saturated nuclear matter is modeled by
scalar and vector mean fields for the nucleon. It is shown that the short-range
dressing of the pi N Delta vertex has a significant effect on the pion and
isobar properties. Using realistic parameters sets we predict a downward shift
of about 50 MeV for the Delta resonance at nuclear saturation density. The
pionic soft modes are much less pronounced than in previous studies.


title: The Antares emission nebula and mass loss of alpha Sco A

abstract:
  The Antares nebula is a peculiar emission nebula seen in numerous Fe II lines
and in radio free-free emission, probably associated with the H II region
caused by alpha Sco B in the wind of alpha Sco A. High-resolution spectra with
spatial resolution were used to study the emission line spectrum, the physical
nature of the nebula and to determine the mass-loss rate of the M supergiant
alpha Sco A.


title: Generation of Vorticity and Velocity Dispersion by Orbit Crossing

abstract:
  We study the generation of vorticity and velocity dispersion by orbit
crossing using cosmological numerical simulations, and calculate the
backreaction of these effects on the evolution of large-scale density and
velocity divergence power spectra. We use Delaunay tessellations to define the
velocity field, showing that the power spectra of velocity divergence and
vorticity measured in this way are unbiased and have better noise properties
than for standard interpolation methods that deal with mass weighted
velocities. We show that high resolution simulations are required to recover
the correct large-scale vorticity power spectrum, while poor resolution can
spuriously amplify its amplitude by more than one order of magnitude. We
measure the scalar and vector modes of the stress tensor induced by orbit
crossing using an adaptive technique, showing that its vector modes lead, when
input into the vorticity evolution equation, to the same vorticity power
spectrum obtained from the Delaunay method. We incorporate orbit crossing
corrections to the evolution of large scale density and velocity fields in
perturbation theory by using the measured stress tensor modes. We find that at
large scales (k~0.1 h/Mpc) vector modes have very little effect in the density
power spectrum, while scalar modes (velocity dispersion) can induce percent
level corrections at z=0, particularly in the velocity divergence power
spectrum. In addition, we show that the velocity power spectrum is smaller than
predicted by linear theory until well into the nonlinear regime, with little
contribution from virial velocities.


title:
Perturbative and non-perturbative studies with the delta function
  potential

abstract:
  We show that the delta function potential can be exploited along with
perturbation theory to yield the result of certain infinite series. The idea is
that any exactly soluble potential if coupled with a delta function potential
remains exactly soluble. We use the strength of the delta function as an
expansion parameter and express the second-order energy shift as an infinite
sum in perturbation theory. The analytical solution is used to determine the
second-order energy shift and hence the sum of an infinite series. By an
appropriate choice of the unperturbed system, we can show the importance of the
continuum in the energy shift of bound states.


title: Photoabsorption off nuclei with self consistent vertex corrections

abstract:
  We study photoproduction off nuclei based on a self consistent and covariant
many body approach for the pion and isobar propagation in infinite nuclear
matter. For the first time the t-channel exchange of an in-medium pion is
evaluated in the presence of vertex correction effects consistently. In
particular the interference pattern with the s-channel in-medium nucleon and
isobar exchange contribution is considered. Electromagnetic gauge invariance is
kept as a consequence of various Ward identities obeyed by the computation.
Adjusting the set of Migdal parameters to the data set we predict an attractive
mass shift for the isobar of about 50 MeV at nuclear saturation density.


title: Variational Constrained Mechanics on Lie Affgebroids

abstract:
  In this paper we discuss variational constrained mechanics (vakonomic
mechanics) on Lie affgebroids. We obtain the dynamical equations and the
aff-Poisson bracket associated with a vakonomic system on a Lie affgebroid
${\mathcal A}$. We devote special attention to the particular case when the
nonholonomic constraints are given by an affine subbundle of ${\mathcal A}$ and
we discuss the variational character of the theory. Finally, we apply the
results obtained to several examples.


title:
Search of Weighted Subgraphs on Complex Networks with Maximum Likelihood
  Methods

abstract:
  Real-data networks often appear to have strong modularity, or
network-of-networks structure, in which subgraphs of various size and
consistency occur. Finding the respective subgraph structure is of great
importance, in particular for understanding the dynamics on these networks.
Here we study modular networks using generalized method of maximum likelihood.
We first demonstrate how the method works on computer-generated networks with
the subgraphs of controlled connection strengths and clustering. We then
implement the algorithm which is based on weights of links and show its
efficiency in finding weighted subgraphs on fully connected graph and on
real-data network of yeast.


title:
The effects of twisted magnetic field on coronal loops oscillations and
  dissipation

abstract:
  The standing MHD modes in a zero-$\beta$ cylindrical magnetic flux tube
modelled as a straight core surrounded by a magnetically twisted annulus, both
embedded in a straight ambient external field is considered. The dispersion
relation for the fast MHD waves is derived and solved numerically to obtain the
frequencies of both the kink ($m=1$), and fluting ($m=2,3$) waves. Damping
rates due to both viscous and resistive dissipations in presence of the twisted
magnetic field is derived and solved numerically for both the kink and fluting
waves.


title: Optimal length estimates for stable CMC surfaces in 3-space forms

abstract:
  In this paper, we study stable constant mean curvature $H$ surfaces in
$\R^3$. We prove that, in such a surface, the distance from a point to the
boundary is less that $\pi/(2H)$. This upper-bound is optimal and is extended
to stable constant mean curvature surfaces in space forms.


title: Quantum-mechanical description of in-medium fragmentation

abstract:
  We present a quantum-mechanical description of quark-hadron fragmentation in
a nuclear environment. It employs the path-integral formulation of quantum
mechanics, which takes care of all phases and interferences, and which contains
all relevant time scales, like production, coherence, formation, etc. The cross
section includes the probability of pre-hadron (colorless dipole) production
both inside and outside the medium. Moreover, it also includes inside-outside
production, which is a typical quantum-mechanical interference effect (like
twin-slit electron propagation). We observe a substantial suppression caused by
the medium, even if the pre-hadron is produced outside the medium and no energy
loss is involved. This important source of suppression is missed in the usual
energy-loss scenario interpreting the effect of jet quenching observed in heavy
ion collisions. This may be one of the reasons of a too large gluon density,
reported by such analyzes.


title: Realistic shell model; 132Sn region; 208Pb region

abstract:
  We report on a study of exotic nuclei around doubly magic 132Sn in terms of
the shell model employing a realistic effective interaction derived from the
CD-Bonn nucleon-nucleon potential. The short-range repulsion of the latter is
renormalized by constructing a smooth low-momentum potential, V-low-k, that is
used directly as input for the calculation of the effective interaction. In
this paper, we focus attention on proton-neutron multiplets in the odd-odd
nuclei 134Sb, 136Sb. We show that the behavior of these multiplets is quite
similar to that of the analogous multiplets in the counterpart nuclei in the
208Pb region, 210Bi and 212Bi.


title: Correlation, hierarchies, and networks in financial markets

abstract:
  We discuss some methods to quantitatively investigate the properties of
correlation matrices. Correlation matrices play an important role in portfolio
optimization and in several other quantitative descriptions of asset price
dynamics in financial markets. Specifically, we discuss how to define and
obtain hierarchical trees, correlation based trees and networks from a
correlation matrix. The hierarchical clustering and other procedures performed
on the correlation matrix to detect statistically reliable aspects of the
correlation matrix are seen as filtering procedures of the correlation matrix.
We also discuss a method to associate a hierarchically nested factor model to a
hierarchical tree obtained from a correlation matrix. The information retained
in filtering procedures and its stability with respect to statistical
fluctuations is quantified by using the Kullback-Leibler distance.

categories: q-fin.ST physics.data-an physics.soc-ph q-fin.PM


title: Low-resolution measurements induced classicality

abstract:
  The classical limit of quantum mechanics is discussed for closed quantum
systems in terms of observational aspects. Initially, the failure of the limit
h->0 is explicitly demonstrated in a model of two quantum mechanically
interacting oscillators by showing that neither quantum expectations reduce to
Newtonian trajectories nor entanglement vanishes. This result suggests that the
quantum-to-classical transition occurs only at an approximative level, which is
regulated by the low accuracy of the measurements. In order to verify the
consistence of these ideas we take into account the experimental resolution of
physical measurements by introducing a discretized formulation for the quantum
structure of wave functions. As a result, in the low-resolution limit the
quasi-determinism is recovered and hence the quantum-to-classical transition is
shown to occur adequately. Other puzzling problems, such as the classical limit
of quantum superpositions and nonlocal correlations, are naturally address as
well.


title:
Frequency Dependent Specific Heat from Thermal Effusion in Spherical
  Geometry

abstract:
  We present a novel method of measuring the frequency dependent specific heat
at the glass transition applied to 5-polyphenyl-4-ether. The method employs
thermal waves effusing radially out from the surface of a spherical thermistor
that acts as both a heat generator and thermometer. It is a merit of the method
compared to planar effusion methods that the influence of the mechanical
boundary conditions are analytically known. This implies that it is the
longitudinal rather than the isobaric specific heat that is measured. As
another merit the thermal conductivity and specific heat can be found
independently. The method has highest sensitivity at a frequency where the
thermal diffusion length is comparable to the radius of the heat generator.
This limits in practise the frequency range to 2-3 decades. An account of the
3omega-technique used including higher order terms in the temperature
dependency of the thermistor and in the power generated is furthermore given.


title: Explicit R-Symmetry Breaking and Metastable Vacua

abstract:
  We consider O'Raifeartaigh-like models with explicit R-symmetry breaking and
analyze the vacuum landscape. Taking such models as candidates for the hidden
sector, we analyze the gauge mediation of the supersymmetry breaking, focusing
on the effects produced by R-symmetry breaking. First, we construct families of
non-R-symmetric models containing only singlet chiral superfields, and
determine the conditions under which SUSY vacua, runaway directions and
(longlived) metastable vacua exist. We then extend the results to the case in
which some of the chiral fields are in a non-trivial representation of SU(5).
Gauging this symmetry, we compute soft masses for gauginos and sfermions, and
analyze several issues such as doublet/triplet splitting, unification of
coupling constants and CP violation phases.


title: Coordinated AMBER and MIDI observations of the Mira variable RR Aql

abstract:
  We have used near- and mid-infrared interferometry to investigate the
pulsating atmosphere and the circumstellar environment of the Mira variable RR
Aql. Observations were taken with the VLTI/AMBER (near infrared) and the
VLTI/MIDI (mid infrared) instruments. We have obtained a total of 15 MIDI
epochs between Apr 9, 2004 and Jul 28, 2007 covering 4 pulsation cycles and one
AMBER epoch on Sep 9, 2006 at phase 2.82. This work is also part of an ongoing
project of joint VLTI and VLBA observations to study the connection between
stellar pulsation and the mass loss process. Here we present a comparison of
the AMBER visibility data to a simple uniform disk model as well as to
predictions by recent self-excited dynamic model atmospheres. The best fitting
photospheric angular diameter of the model atmosphere at phase 2.82 is 9.9 +/-
2.4 mas.


title:
High-pressure x-ray diffraction study on the structure and phase
  transitions of the defect-stannite ZnGa2Se4 and defect-chalcopyrite CdGa2S4

abstract:
  X-ray diffraction measurements on the sphalerite-derivatives ZnGa2Se4 and
CdGa2S4 have been performed upon compression up to 23 GPa in a diamond-anvil
cell. ZnGa2Se4 exhibits a defect tetragonal stannite-type structure (I-42m) up
to 15.5 GPa and in the range from 15.5 GPa to 18.5 GPa the low-pressure phase
coexists with a high-pressure phase, which remains stable up to 23 GPa. In
CdGa2S4, we find the defect tetragonal chalcopyrite-type structure (I-4) is
stable up to 17 GPa. Beyond this pressure a pressure-induced phase transition
takes place. In both materials, the high-pressure phase has been characterized
as a defect-cubic NaCl-type structure (Fm-3m). The occurrence of the pressure
induced phase transitions is apparently related with an increase of the cation
disorder on the semiconductors investigated. In addition, the results allow the
evaluation of the axial compressibility and the determination of the equation
of state for each compound. The obtained results are compared with those
previously reported for isomorphic digallium sellenides. Finally, a systematic
study of the pressure-induced phase transition in twenty-three different
sphalerite-related ABX2 and AB2X4 compounds indicates that the transition
pressure increases as the ratio of the cationic radii and anionic radii of the
compounds increases.


title: Explicit constructions of infinite families of MSTD sets

abstract:
  We explicitly construct infinite families of MSTD (more sums than
differences) sets. There are enough of these sets to prove that there exists a
constant C such that at least C / r^4 of the 2^r subsets of {1,...,r} are MSTD
sets; thus our family is significantly denser than previous constructions
(whose densities are at most f(r)/2^{r/2} for some polynomial f(r)). We
conclude by generalizing our method to compare linear forms epsilon_1 A + ... +
epsilon_n A with epsilon_i in {-1,1}.


title:
A computational approach to the covert and overt deployment of spatial
  attention

abstract:
  Popular computational models of visual attention tend to neglect the
influence of saccadic eye movements whereas it has been shown that the primates
perform on average three of them per seconds and that the neural substrate for
the deployment of attention and the execution of an eye movement might
considerably overlap. Here we propose a computational model in which the
deployment of attention with or without a subsequent eye movement emerges from
local, distributed and numerical computations.


title: POCP: a package for polynomial optimal control problems

abstract:
  POCP is a new Matlab package running jointly with GloptiPoly 3 and,
optionally, YALMIP. It is aimed at nonlinear optimal control problems for which
all the problem data are polynomial, and provides an approximation of the
optimal value as well as some control policy. Thanks to a user-friendly
interface, POCP reformulates such control problems as generalized problems of
moments, in turn converted by GloptiPoly 3 into a hierarchy of semidefinite
programming problems whose associated sequence of optimal values converges to
the optimal value of the polynomial optimal control problem. In this paper we
describe the basic features of POCP and illustrate them with some numerical
examples.


title: CMB likelihood approximation by a Gaussianized Blackwell-Rao estimator

abstract:
  We introduce a new CMB temperature likelihood approximation called the
Gaussianized Blackwell-Rao (GBR) estimator. This estimator is derived by
transforming the observed marginal power spectrum distributions obtained by the
CMB Gibbs sampler into standard univariate Gaussians, and then approximate
their joint transformed distribution by a multivariate Gaussian. The method is
exact for full-sky coverage and uniform noise, and an excellent approximation
for sky cuts and scanning patterns relevant for modern satellite experiments
such as WMAP and Planck. A single evaluation of this estimator between l=2 and
200 takes ~0.2 CPU milliseconds, while for comparison, a single pixel space
likelihood evaluation between l=2 and 30 for a map with ~2500 pixels requires
~20 seconds. We apply this tool to the 5-year WMAP temperature data, and
re-estimate the angular temperature power spectrum, $C_{\ell}$, and likelihood,
L(C_l), for l<=200, and derive new cosmological parameters for the standard
six-parameter LambdaCDM model. Our spectrum is in excellent agreement with the
official WMAP spectrum, but we find slight differences in the derived
cosmological parameters. Most importantly, the spectral index of scalar
perturbations is n_s=0.973 +/- 0.014, 1.9 sigma away from unity and 0.6 sigma
higher than the official WMAP result, n_s = 0.965 +/- 0.014. This suggests that
an exact likelihood treatment is required to higher l's than previously
believed, reinforcing and extending our conclusions from the 3-year WMAP
analysis. In that case, we found that the sub-optimal likelihood approximation
adopted between l=12 and 30 by the WMAP team biased n_s low by 0.4 sigma, while
here we find that the same approximation between l=30 and 200 introduces a bias
of 0.6 sigma in n_s.


title:
Applications of Automata and Graphs: Labeling Operators in Hilbert Space
  II

abstract:
  We introduced a family of infinite graphs directly associated with a class of
von Neumann automaton model A_{G}. These are finite state models used in
symbolic dynamics: stimuli models and in control theory. In the context of
groupoid von Neumann algebras, and an associated fractal group, we prove a
classification theorem for representations of automata.


title: Laser Induced Selective Alignment of Water Spin Isomers

abstract:
  We consider laser alignment of ortho and para spin isomers of water molecules
by using strong and short off-resonance laser pulses. A single pulse is found
to create a distinct transient alignment and antialignment of the isomeric
species. We suggest selective alignment of one isomeric species (leaving the
other species randomly aligned) by a pair of two laser pulses.


title: Solving the 100 Swiss Francs Problem

abstract:
  Sturmfels offered 100 Swiss Francs in 2005 to a conjecture, which deals with
a special case of the maximum likelihood estimation for a latent class model.
This paper confirms the conjecture positively.


title: Time variation of fundamental couplings and dynamical dark energy

abstract:
  Scalar field dynamics may give rise to a nonzero cosmological variation of
fundamental constants. Within different scenarios based on the unification of
gauge couplings, the various claimed observations and bounds may be combined in
order to trace or restrict the time history of the couplings and masses. If the
scalar field is responsible for a dynamical dark energy or quintessence,
cosmological information becomes available for its time evolution. Combining
this information with the time variation of couplings, one can determine the
interaction strength between the scalar and atoms, which may be observed by
tests of the Weak Equivalence Principle. We compute bounds on the present rate
of coupling variation from experiments testing the differential accelerations
for bodies with equal mass and different composition and compare the
sensitivity of various methods. In particular, we discuss two specific models
of scalar evolution: crossover quintessence and growing neutrino models.


title:
Infinitesimal Morita homomorphisms and the tree-level of the LMO
  invariant

abstract:
  Let S be a compact connected oriented surface with one boundary component,
and let P be the fundamental group of S. The Johnson filtration is a decreasing
sequence of subgroups of the Torelli group of S, whose k-th term consists of
the self-homeomorphisms of S that act trivially at the level of the k-th
nilpotent quotient of P. Morita defined a homomorphism from the k-th term of
the Johnson filtration to the third homology group of the k-th nilpotent
quotient of P. In this paper, we replace groups by their Malcev Lie algebras
and we study the "infinitesimal" version of the k-th Morita homomorphism, which
is shown to correspond to the original version by a canonical isomorphism. We
provide a diagrammatic description of the k-th infinitesimal Morita
homomorphism and, given an expansion of the free group P that is "symplectic"
in some sense, we show how to compute it from Kawazumi's "total Johnson map".
Besides, we give a topological interpretation of the full tree-reduction of the
LMO homomorphism, which is a diagrammatic representation of the Torelli group
derived from the Le-Murakami-Ohtsuki invariant of 3-manifolds. More precisely,
a symplectic expansion of P is constructed from the LMO invariant, and it is
shown that the tree-level of the LMO homomorphism is equivalent to the total
Johnson map induced by this specific expansion. It follows that the k-th
infinitesimal Morita homomorphism coincides with the degree [k,2k[ part of the
tree-reduction of the LMO homomorphism. Our results also apply to the monoid of
homology cylinders over S.


title: Charge Transport in Disordered Graphene-Based Low Dimensional Materials

abstract:
  Two-dimensional graphene, carbon nanotubes and graphene nanoribbons represent
a novel class of low dimensional materials that could serve as building blocks
for future carbon-based nanoelectronics. Although these systems share a similar
underlying electronic structure, whose exact details depend on confinement
effects, crucial differences emerge when disorder comes into play. In this
short review, we consider the transport properties of these materials, with
particular emphasis to the case of graphene nanoribbons. After summarizing the
electronic and transport properties of defect-free systems, we focus on the
effects of a model disorder potential (Anderson-type), and illustrate how
transport properties are sensitive to the underlying symmetry. We provide
analytical expressions for the elastic mean free path of carbon nanotubes and
graphene nanoribbons, and discuss the onset of weak and strong localization
regimes, which are genuinely dependent on the transport dimensionality. We also
consider the effects of edge disorder and roughness for graphene nanoribbons in
relation to their armchair or zigzag orientation.


title: Simple field theoretical approach of Coulomb systems. Entropic effects

abstract:
  We discuss a new simple field theory approach of Coulomb systems. Using a
description in terms of fields, we introduce in a new way the statistical
degrees of freedom in relation with the quantum mechanics. We show on a series
of examples that these fundamental entropic effects can help account for
physical phenomena in relation with Coulomb systems whether symmetric or also
asymmetric in valence. On the overall, this gives a new understanding of these
systems.


title: Surrogate Learning - An Approach for Semi-Supervised Classification

abstract:
  We consider the task of learning a classifier from the feature space
$\mathcal{X}$ to the set of classes $\mathcal{Y} = \{0, 1\}$, when the features
can be partitioned into class-conditionally independent feature sets
$\mathcal{X}_1$ and $\mathcal{X}_2$. We show the surprising fact that the
class-conditional independence can be used to represent the original learning
task in terms of 1) learning a classifier from $\mathcal{X}_2$ to
$\mathcal{X}_1$ and 2) learning the class-conditional distribution of the
feature set $\mathcal{X}_1$. This fact can be exploited for semi-supervised
learning because the former task can be accomplished purely from unlabeled
samples. We present experimental evaluation of the idea in two real world
applications.


title:
Bounds on Sobolev norms for the nonlinear Schr\"odinger equation on
  general tori

abstract:
  We prove Strichartz estimates on general flat d-torus for arbitrary d. Using
these estimates, we prove local wellposedness for the cubic nonlinear
Schr\"odinger equations in appropriate Sobolev spaces. In dimensions 2 and 3,
we prove polynomial bounds on the possible growth of Sobolev norms of smooth
solutions.


title: Spectral variability of ultraluminous X-ray sources

abstract:
  We study spectral variability of 11 ultraluminous X-ray sources (ULX) using
archived XMM-Newton and Chandra observations. We use three models to describe
the observed spectra; a power-law, a multi-colour disk (MCD) and a combination
of these two models. We find that out of the 11 ULXs in our sample, 7 ULXs show
a correlation between the luminosity and the photon index Gamma (hereafter
L-Gamma correlation). Furthermore, out of the 7 ULXs that have the L-Gamma
correlation, 4 ULXs also show spectral pivoting in the observed energy band. We
also find that two ULXs show an L-Gamma anti-correlation. The spectra of 4 ULXs
in the sample can be adequately fitted with a MCD model. We compare these
sources to known black hole binaries (BHB) and find that they follow similar
paths in their luminosity-temperature (hereafter L-T) diagrams. Finally we show
that the 'soft excess' reported for many of these ULXs at 0.2 keV seem to
follow a trend L \propto T^{-4} when modeled with a power-law plus a 'cool' MCD
model. This is contrary to the expected L \propto T^4 relation that is expected
from theory and what is seen for many accreting BHBs.


title: Mechanistic Behavior of Single-Pass Instruction Sequences

abstract:
  Earlier work on program and thread algebra detailed the functional,
observable behavior of programs under execution. In this article we add the
modeling of unobservable, mechanistic processing, in particular processing due
to jump instructions. We model mechanistic processing preceding some further
behavior as a delay of that behavior; we borrow a unary delay operator from
discrete time process algebra. We define a mechanistic improvement ordering on
threads and observe that some threads do not have an optimal implementation.


title:
Extrasolar planets and brown dwarfs around A-F type stars VI. High
  precision RV survey of early type dwarfs with HARPS

abstract:
  (Abridged) Aims: Systematic surveys to search for exoplanets have been mostly
dedicated to solar-type stars sofar. We developed in 2004 a method to extend
such searches to earlier A-F type dwarfs and started spectroscopic surveys to
search for planets and quantify the detection limit achievable when taking into
account the stars properties and their actual levels of intrinsic variations.
We give here the first results of our southern survey with HARPS.
  Results: 1) 64% of the 170 stars with enough data points are found to be
variable. 20 are found to be binaries or candidate binaries (with stars or
brown dwarfs). More than 80% or the latest type stars (once binaries are
removed) are intrinsically variable at a 2 m/s precision level. Stars with
earlier spectral type (B-V <= 0.2) are either variable or associated to levels
of uncertainties comparable to the RV rms observed on variable stars of same
B-V. 2) We have detected one long-period planetary system around an F6IV-V
star. 3) We have quantified the jitter due to stellar activity and we show that
taking into account this jitter in addition to the stellar parameters, it is
still possible to detect planets with HARPS with periods of 3 days (resp. 10
days and 100 days) on 91% (resp. 83%, 61%) of them. We show that even the
earliest spectral type stars are accessible to this type of search, provided
they have a low vsini and low levels of activity. 4) Taking into account the
present data, we compute the actually achieved detection limits for 107 targets
and discuss the limits as a function of B-V. Given the data at hand, our survey
is sensitive to short-period (few days) planets and to longer ones (100 days)
at a lower extent (latest type stars). We derive first constrains on the
presence of planets around A-F stars for these ranges of periods.


title:
Introducing a Hybrid Method of Radiative Transfer in Smoothed Particle
  Hydrodynamics

abstract:
  We present a new method of incorporating radiative transfer into Smoothed
Particle Hydrodynamics (SPH). There have been many recent attempts at radiative
transfer in SPH (Stamatellos et al 2005, 2005, Mayer et al 2007, Whitehouse and
Bate 2006), however these are becoming increasingly complex, with some methods
requiring the photosphere to be mapped (which is often of non-trivial geometric
shape), and extra conditions to be applied there (matching atmospheres as in
Cai et al (2008), or specifying cooling at the photosphere as in Mayer et al
(2007)). The method of identifying the photosphere is usually a significant
addition to the total simulation runtime, and often requires extra free
parameters, the changing of which will affect the final results. Our method is
not affected by such concerns, as the photosphere is constructed implicitly by
the algorithm without the need for extra free parameters. The algorithm used is
a synergy of two current formalisms for radiative effects: a) the polytropic
cooling formalism proposed by Stamatellos et al (2007), and b) flux-limited
diffusion, used by many authors to simulate radiation transport in the
optically thick regime (e.g. Mayer et al 2007). We present several tests of
this method: (1) The evolution of a 0.07 solar mass protoplanetary disc around
a 0.5 solarmass star (Pickett et al 2003, Mejia et al 2005, Boley et al 2006,
Cai et al 2008); (2) The collapse of a non-rotating 1 solar mass molecular
cloud (Masunaga & Inutsuka 2000, Stamatellos et al 2007); (3) The thermal
relaxation of temperature fluctuations in an static homogeneous sphere
(Masunaga et al 1998, Spiegel 1957, Stamatellos et al 2007)


title: Tools for event generator tuning and validation

abstract:
  I describe the current status of MCnet tools for validating the performance
of event generator simulations against data, and for tuning their
phenomenological free parameters. For validation, the Rivet toolkit is now a
mature and complete system, with a large library of prominent benchmark
analyses. For tuning, the Professor system has recently completed its first
tunes of Pythia 6, with substantial improvements on the existing default tune
and potential to greatly aid the setup of new generators for LHC studies.


title: DNA adsorption at liquid/solid interfaces

abstract:
  DNA adsorption on solid or liquid surfaces is a topic of broad fundamental
and applied interest. Here we study by x-ray reflectivity the adsorption of
monodisperse double-stranded DNA molecules a positively-charged surface,
obtained through chemical grafting of a homogeneous organicmonomolecular layer
of N-(2-aminoethyl) dodecanamide on an oxide-free monocrystalline Si(111)
wafer. The adsorbed dsDNA is found to embed into the soft monolayer which is
deformed in the process. The surface coverage is very high and this adsorbed
layer is expected to display 2D nematic ordering.


title: Sensitivity for Smoluchowski equation

abstract:
  This article investigates the question of sensitivity of the solutions of
Smoluchowski equation on R_+^* with respect to parameters \lambda in the
interaction kernel K^lambda. It is proved that the solution is a C^1 function
of (t,lambda) with values in a good space of measures under the hypotheses
K^{lambda}(x,y) \leq phi(x)phi(y), for some sub-linear function phi, a
(4+epsilon)-moment assumption on the initial condition, and that the derivative
is a solution, in a suitable sense, of a linearized equation.


title: QCD Radiation Effects on the H->WW->l nu l nu Signal at Hadron Colliders

abstract:
  The discovery of a Standard Model Higgs boson is possible when experimental
cuts are applied which increase the ratio of signal and background
cross-sections. We present a study of the pp->H->WW signal cross-section at
hadron colliders which requires a selection of Higgs bosons with small
transverse momentum. We compare predictions for the efficiency of the
experimental cuts from a NNLO QCD calculation and the event generator MC@NLO
and are able to predict a reliable number for the cross-section after the
aplpication of such experimental cuts.


title:
Emergent self-organized complex network topology out of stability
  constraints

abstract:
  Although most networks in nature exhibit complex topology the origins of such
complexity remains unclear. We introduce a model of a growing network of
interacting agents in which each new agent's membership to the network is
determined by the agent's effect on the network's global stability. It is shown
that out of this stability constraint, scale free networks emerges in a self
organized manner, offering an explanation for the ubiquity of complex
topological properties observed in biological networks.


title: Thermoelectric transport in billiard systems

abstract:
  We discuss the thermoelectric (TE) transport in billiard systems of
interacting particles, coupled to stochastic particle reservoirs. Recently in
[1], analytical exact expressions for the TE transport of noninteracting gases
of polyatomic molecules were obtained, and a novel microscopic mechanism for
the increase of thermoelectric efficiency described. After briefly reviewing
the derivation of [1], in this paper we focus on the effects that the
particle-particle interaction has on the TE efficiency. We show that
interaction reduces the maximal thermodynamic efficiency. However, the
mechanism for the efficiency's increase towards its Carnot upper limit,
described in [1], remains unaffected.


title: Damping and magnetic anisotropy of ferromagnetic GaMnAs thin films

abstract:
  The magnetic properties of annealed, epitaxial Ga0.93Mn0.07As layers under
tensile and compressive stress have been investigated by X-band (9GHz) and
Q-band (35GHz) ferromagnetic resonance (FMR) spectroscopy. From the analysis of
the linewidths of the uniform mode spectra the FMR Gilbert damping factor
"alpha" has been determined. At T=4K we obtain a minimum damping factor of
"alpha" = 0.003 for the compressively stressed layer. Its value is not
isotropic. It has a minimum value for the easy axes orientations of the
magnetic field and increases with the measuring temperature. Its average value
is for both type of films of the order of 0.01 in spite of strong differences
in the inhomogeneous linewidth which vary between 20 Oe and 600 Oe for the
layers grown on GaAs and GaInAs substrates respectively.


title: Radio Remote Sensing of the Corona and the Solar Wind

abstract:
  Modern radio telescopes are extremely sensitive to plasma on the line of
sight from a radio source to the antenna. Plasmas in the corona and solar wind
produce measurable changes in the radio wave amplitude and phase, and the phase
difference between wave fields of opposite circular polarization. Such
measurements can be made of radio waves from spacecraft transmitters and
extragalactic radio sources, using radio telescopes and spacecraft tracking
antennas. Data have been taken at frequencies from about 80 MHz to 8000 MHz.
Lower frequencies probe plasma at greater heliocentric distances. Analysis of
these data yields information on the plasma density, density fluctuations, and
plasma flow speeds in the corona and solar wind, and on the magnetic field in
the solar corona. This paper will concentrate on the information that can be
obtained from measurements of Faraday rotation through the corona and inner
solar wind. The magnitude of Faraday rotation is proportional to the line of
sight integral of the plasma density and the line-of-sight component of the
magnetic field. Faraday rotation provides an almost unique means of estimating
the magnetic field in this part of space. This technique has contributed to
measurement of the large scale coronal magnetic field, the properties of
electromagnetic turbulence in the corona, possible detection of electrical
currents in the corona, and probing of the internal structure of coronal mass
ejections (CMEs). This paper concentrates on the search for small-scale coronal
turbulence and remote sensing of the structure of CMEs. Future investigations
with the Expanded Very Large Array (EVLA) or Murchison Widefield Array (MWA)
could provide unique observational input on the astrophysics of CMEs.


title: Non-linear isocurvature perturbations and non-Gaussianities

abstract:
  We study non-linear primordial adiabatic and isocurvature perturbations and
their non-Gaussianity. After giving a general formulation in the context of an
extended delta N-formalism, we analyse in detail two illustrative examples. The
first is a mixed curvaton-inflaton scenario in which fluctuations of both the
inflaton and a curvaton (a light isocurvature field during inflation)
contribute to the primordial density perturbation. The second example is that
of double inflation involving two decoupled massive scalar fields during
inflation. In the mixed curvaton-inflaton scenario we find that the bispectrum
of primordial isocurvature perturbations may be large and comparable to the
bispectrum of adiabatic curvature perturbations.


title:
Series expansions in Fr\'echet spaces and their duals; construction of
  Fr\'echet frames

abstract:
  Frames for Fr\'echet spaces $X_F$ with respect to Fr\'echet sequence spaces
$\Theta_F$ are studied and conditions, implying series expansions in $X_F$ and
$X_F^*$, are determined. If $\{g_i\}$ is a $\Theta_0$-frame for $X_0$, we
construct a sequence $\{X_s\}_{s\in {\mathbb N}_0}$, $X_s\subset X_{s-1}$,
$s\in {\mathbb N}$, for given $\Theta_F$, respectively a sequence
$\{\Theta_s\}_{s\in {\mathbb N}_0}$, $\Theta_s\subset \Theta_{s-1}$, $s\in
{\mathbb N}$, for given $X_F$, so that $\{g_i\}$ is a pre-$F$-frame (or
$F$-frame) for $X_F$ with respect to $\Theta_F$ under different assumptions
given on $X_0$, $\Theta_0$, $\Theta_F$ or $X_0$, $\Theta_0$, $X_F$.


title:
Magnetic fields, winds and X-rays of massive stars: A
  spectropolarimetric survey of the Orion cluster

abstract:
  In massive stars, magnetic fields are thought to confine the outflowing
radiatively-driven wind, resulting in X-ray emission that is harder, more
variable and more efficient than that produced by instability-generated shocks
in non-magnetic winds. Although magnetic confinement of stellar winds has been
shown to strongly modify the mass-loss and X-ray characteristics of massive OB
stars, we lack a detailed understanding of the complex processes responsible.
The aim of this study is to examine the relationship between magnetism, stellar
winds and X-ray emission of OB stars. In conjunction with a Chandra survey of
the Orion Nebula Cluster, we carried out spectropolarimatric ESPaDOnS
observations to determine the magnetic properties of massive OB stars of this
cluster. We found of two new massive magnetic stars in the Orion Nebula
Cluster: HD 36982 and HD 37061, for which the estimated dipole polar strengths
are 1150 (+320 -200) G and 620 (+220 -170) G, respectively. However, the
apparent lack of clear correlation between X-ray indicator and the presence of
a magnetic fields brings forth new challenges for understanding the processes
leading to X-ray emission in massive stars.


title:
Domain wall displacement in Py square ring for single nanometric
  magnetic bead detection

abstract:
  A new approach based on the domain wall displacement in confined
ferromagnetic nanostructures for attracting and sensing a single nanometric
magnetic particles is presented. We modeled and experimentally demonstrated the
viability of the approach using an anisotropic magnetoresistance device made by
a micron-size square ring of Permalloy designed for application in magnetic
storage. This detection concept can be suitable to biomolecular recognition,
and in particular to single molecule detection.


title:
Completeness of determinantal Hamiltonian flows on the matrix affine
  Poisson space

abstract:
  The matrix affine Poisson space (M_{m,n}, pi_{m,n}) is the space of complex
rectangular matrices equipped with a canonical quadratic Poisson structure
which in the square case m=n reduces to the standard Poisson structure on
GL_n(C). We prove that the Hamiltonian flows of all minors are complete. As a
corollary we obtain that all Kogan-Zelevinsky integrable systems on M_{n,n} are
complete and thus induce (analytic) Hamiltonian actions of C^{n(n-1)/2} on
(M_{n,n}, pi_{n,n}) (as well as on GL_n(C) and on SL_n(C)).
  We define Gelfand-Zeitlin integrable systems on (M_{n,n}, pi_{n,n}) from
chains of Poisson projections and prove that their flows are also complete.
This is an analog for the quadratic Poisson structure pi_{n,n} of the recent
result of Kostant and Wallach [KW] that the flows of the complexified classical
Gelfand-Zeitlin integrable systems are complete.


title:
Regularization of almost complex structures and and gluing holomorphic
  discs to tori

abstract:
  We prove a result on removing singularities of almost complex structures
pulled back by a non-diffeomorphic map. As an application we prove the
existence of global J-holomorphic discs with boundaries attached to real tori.


title:
Thermodynamic instability and first-order phase transition in an ideal
  Bose gas

abstract:
  We conduct a rigorous investigation into the thermodynamic instability of
ideal Bose gas confined in a cubic box, without assuming thermodynamic limit
nor continuous approximation. Based on the exact expression of canonical
partition function, we perform numerical computations up to the number of
particles one million. We report that if the number of particles is equal to or
greater than a certain critical value, which turns out to be 7616, the ideal
Bose gas subject to Dirichlet boundary condition reveals a thermodynamic
instability. Accordingly we demonstrate - for the first time - that, a system
consisting of finite number of particles can exhibit a discontinuous phase
transition featuring a genuine mathematical singularity, provided we keep not
volume but pressure constant. The specific number, 7616 can be regarded as a
characteristic number of 'cube' that is the geometric shape of the box.


title:
Point classification of 2nd order ODEs: Tresse classification revisited
  and beyond

abstract:
  In 1896 Tresse gave a complete description of relative differential
invariants for the pseudogroup action of point transformations on the 2nd order
ODEs. The purpose of this paper is to review, in light of modern geometric
approach to PDEs, this classification and also discuss the role of absolute
invariants and the equivalence problem.


title: Smooth supersaturated models

abstract:
  In areas such as kernel smoothing and non-parametric regression there is
emphasis on smooth interpolation and smooth statistical models. Splines are
known to have optimal smoothness properties in one and higher dimensions. It is
shown, with special attention to polynomial models, that smooth interpolators
can be constructed by first extending the monomial basis and then minimising a
measure of smoothness with respect to the free parameters in the extended
basis. Algebraic methods are a help in choosing the extended basis which can
also be found as a saturated basis for an extended experimental design with
dummy design points. One can get arbitrarily close to optimal smoothing for any
dimension and over any region, giving a simple alternative models of spline
type. The relationship to splines is shown in one and two dimensions. A case
study is given which includes benchmarking against kriging methods.


title:
Animating the development of Social Networks over time using a dynamic
  extension of multidimensional scaling

abstract:
  The animation of network visualizations poses technical and theoretical
challenges. Rather stable patterns are required before the mental map enables a
user to make inferences over time. In order to enhance stability, we developed
an extension of stress-minimization with developments over time. This dynamic
layouter is no longer based on linear interpolation between independent static
visualizations, but change over time is used as a parameter in the
optimization. Because of our focus on structural change versus stability the
attention is shifted from the relational graph to the latent eigenvectors of
matrices. The approach is illustrated with animations for the journal citation
environments of Social Networks, the (co-)author networks in the carrying
community of this journal, and the topical development using relations among
its title words. Our results are also compared with animations based on
PajekToSVGAnim and SoNIA.


title: Suzaku Observations of the Circinus galaxy

abstract:
  We report Suzaku observations of the active, Compton-thick Circinus galaxy.
Observations were obtained with both the X-ray Imaging spectrometer (XIS) and
the Hard X-ray Detector (HXD). Below 10 keV, the nuclear spectrum is dominated
by radiation reflected from cold dense gas of high column density, while above
13 keV the radiation is directly transmitted nuclear emission seen through a
column density of $~ 4 x 10^{24} cm^-2. In the 0.2--10 keV band, the XIS
spectrum is contaminated at 5% level by the brightest off-nuclear source in
Circinus (CG X-1), but drops to 1% in the 5-10 keV and is negligible at higher
energies. We find no significant evidence for variability in the hard (>12 keV)
emission. The Circinus is marginally detected with the HXD/GSO in the 50--100
keV band at 2.5\sigma level. We model the 3-70 keV band XIS+PIN spectra with a
four components: the Compton transmitted nuclear emission, the reflected
nuclear emission, a soft power law (representing a combination of scattered
nuclear emission, extended emission and contamination by sources in the galaxy
below a few keV). The hard nuclear power-law is found to have a photon index
Gamma_h ~= 1.6, very similar to the soft power-law. The high energy cut-off is
E_C ~= 49 keV. These results agree with those from BeppoSax. An extrapolation
of this model up to the GSO band shows good agreement with the GSO spectrum and
supports our detection of the Circinus up to ~= 100keV.


title: Stable propagation of a modulated particle beam in a crystal channel

abstract:
  The propagation of a modulated beam of charged particles in a planar crystal
channel is investigated. It is demonstrated that the beam preserves its
modulation at sufficiently large penetration depths to ensure the feasibility
of using a crystalline undulator as a coherent source of hard X rays. This
finding is a crucial milestone in developing a new type of lasers radiating in
the hard X ray and gamma ray range.


title:
Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg
  to a Quantum Compass and Kitaev Models

abstract:
  We study the magnetic interactions in Mott-Hubbard systems with partially
filled $t_{2g}$-levels and with strong spin-orbit coupling. The latter
entangles the spin and orbital spaces, and leads to a rich variety of the low
energy Hamiltonians that extrapolate from the Heisenberg to a quantum compass
model depending on the lattice geometry. This gives way to "engineer" in such
Mott insulators an exactly solvable spin model by Kitaev relevant for quantum
computation. We, finally, explain "weak" ferromagnetism, with an anomalously
large ferromagnetic moment, in Sr$_2$IrO$_4$.


title: Unique Signatures of Unparticle Resonances at the LHC

abstract:
  The coupling of unparticles to the Standard Model (SM) Higgs boson leads to a
breaking of conformal symmetry which produces an effective mass term in the
unparticle propagator. Simultaneously, the unparticle couplings to other SM
fields produces an effective unparticle decay width via one-loop self-energy
graphs. The resulting unparticle propagator then leads to a rather unique
appearance for the shape of unparticle resonances that are not of the usual
Breit-Wigner variety when they form in high energy collisions. In this paper we
explore whether or not such resonances, appearing in the Drell-Yan channel at
the LHC, can be differentiated from more conventional $Z'$-like structures
which are representative of the typical Breit-Wigner lineshape. We will
demonstrate that even with the high integrated luminosities available at the
LHC it may be difficult to differentiate these two types of resonance
structures for a substantial range of the unparticle model parameters.


title: Anisotropic glass-like properties in tetragonal disordered crystals

abstract:
  The low temperature acoustic and thermal properties of amorphous, glassy
materials are remarkably similar. All these properties are described
theoretically with reasonable quantitative accuracy by assuming that the
amorphous solid contains dynamical defects that can be described at low
temperatures as an ensemble of two-level systems (TLS), but the deep nature of
these TLSs is not clarified yet. Moreover, glassy properties were found also in
disordered crystals, quasicrystals, and even perfect crystals with a large
number of atoms in the unit cell. In crystals, the glassy properties are not
universal, like in amorphous materials, and also exhibit anisotropy. Recently
it was proposed a model for the interaction of two-level systems with arbitrary
strain fields (Phys. Rev. B 75, 64202, 2007), which was used to calculate the
thermal properties of nanoscopic membranes at low temperatures. The model is
also suitable for the description of anisotropic crystals. We describe here the
results of the calculation of anisotropic glass-like properties in crystals of
various lattice symmetries, emphasizing the tetragonal symmetry.


title: Massive B-type pulsators in low-metallicity environments

abstract:
  Massive B type pulsators such as beta Cep and slowly pulsating B (SPB) stars
pulsate due to layers of increased opacity caused by partial ionization. The
increased opacity blocks the energy flux to the surface of the stars which
causes the layers to rise and the opacity to drop. This cyclical behavior makes
the star act as a heat engine and the star will thus pulsate. For beta Cep and
SPB stars the increased opacity is believed to be caused by partial ionization
of iron and these stars should therefore contain non-insignificant quantities
of the metal. A good test of this theory is to search for beta Cep and SPB
stars in low-metallicity environments. If no stars are found the theory is
supported, but on the other hand if a substantial number of beta Cep and SPB
stars are found in these environments then the theory is not supported and a
solutions needed. With a growing number of identified beta Cep and SPB stars in
the low-metallicity Magellanic Clouds we seem to be left with the second case.
We will in this context discuss recent findings of beta Cep and SPB stars in
the Magellanic Clouds and some possible solutions to the discrepancy between
these observations and the theory. We also describe an ambitious project that
we have initiated on the Small Magellanic Cloud open cluster NGC 371 which will
help to evaluate these solutions.


title:
Quasi BPS Wilson loops, localization of loop equation by homology and
  exact beta function in the large N limit of SU(N) Yang-Mills theory

abstract:
  We localize the loop equation of large-N YM theory in the ASD variables on a
critical equation for an effective action by means of homological methods as
opposed to the cohomological localization of equivariantly closed forms in
local field theory. Our localization occurs for some special simple quasi BPS
Wilson loops, that have no perimeter divergence and no cusp anomaly for
backtracking cusps, in a partial Eguchi-Kawai reduction from four to two
dimensions of the non-commutative theory in the limit of infinite
non-commutativity and in a lattice regularization in which the ASD integration
variables live at the points of the lattice, thus implying an embedding of
parabolic Higgs bundles in the YM functional integral. We find that the beta
function of the effective action is saturated by the non-commutative ASD
vortices of the EK reduction. An exact canonical beta function of NSVZ type
that reproduces the universal first and second perturbative coefficients
follows by the localization on vortices. Finally we argue that a scheme can be
found in which the canonical coupling coincides with the physical charge
between static quark sources in the large-N limit and we compare our
theoretical calculation with some numerical lattice result.


title: Bulk viscosity and the conformal anomaly in the pion gas

abstract:
  We calculate the bulk viscosity of the massive pion gas within Unitarized
Chiral Perturbation Theory. We obtain a low temperature peak arising from
explicit conformal breaking due to the pion mass and another peak near the
critical temperature, dominated by the conformal anomaly through gluon
condensate terms. The correlation between bulk viscosity and conformal breaking
supports a recent QCD proposal. We discuss the role of resonances, heavier
states and large-$N_c$ counting.


title: The Atmospheres of Extrasolar Planets

abstract:
  The characteristics of irradiated solar system planetary atmospheres have
been studied for decades, consequently modern planetary science benefits from
an exhaustive body of ground- and space-based data. The study of extrasolar
planetary atmospheres, by contrast, is still in its infancy and currently rests
on a few score of datapoints, mostly of the transiting planets. This short
survey aims not to review this dynamic field but rather stresses the importance
of a few theoretical concepts and processes for our understanding of exoplanet
atmospheres. Topics covered include atmospheric structure and dynamics, cloud
processes and photochemistry of planetary atmospheres. Influences on the
albedos, spectra, and colors of extrasolar planets are reviewed and caution is
urged in the interpretation of exoplanet colors.


title:
A theory of intense-field dynamic alignment and high harmonic generation
  from coherently rotating molecules and interpretation of intense-field
  ultrafast pump-probe experiments

abstract:
  A theory of ultra-fast pump-probe experiments proposed by us earlier [F.H.M.
Faisal et al., Phys. Rev. Lett. 98, 143001 (2007) and F.H.M. Faisal and A.
Abdurrouf, Phys. Rev. Lett. 100, 123005 (2008)] is developed here fully and
applied to investigate the phenomena of dynamic alignment and high harmonic
generation (HHG) from coherently rotating linear molecules. The theory provides
essentially analytical results for the signals that allow us to investigate the
simultaneous dependence of the HHG signals on the two externally available
control parameters, namely, the relative angle between the polarizations, and
the delay-time between the two pulses. It is applied to investigate the
characteristics of high harmonic emission from nitrogen and oxygen molecules
that have been observed experimentally in a number of laboratories. The results
obtained both in the time-domain and in the frequency-domain are compared with
the observed characteristics as well as directly with the data and are found to
agree remarkably well. In addition we have predicted the existence of a "magic"
polarization angle at which all modulations of the harmonic emission from
nitrogen molecule changes to a steady emission at the harmonic frequency. Among
other things we have also shown a correlation between the existence of the
"magic" or critical polarization angles and the symmetry of the active
molecular orbitals, that is deemed to be useful in connection with the "inverse
problem" of molecular imaging from the HHG data.


title: Electromagnetic properties of graphene junctions

abstract:
  A resonant chiral tunneling (CT) across a graphene junction (GJ) induced by
an external electromagnetic field (EF) is studied. Modulation of the electron
and hole wavefunction phases $\varphi$ by the external EF during the CT
processes strongly impacts the CT directional diagram. Therefore the a.c.
transport characteristics of GJs depend on the EF polarization and frequency
considerably. The GJ shows great promises for various nanoelectronic
applications working in the THz diapason.


title:
Superparticle Mass Window from Leptogenesis and Decaying Gravitino Dark
  Matter

abstract:
  Gravitino dark matter, together with thermal leptogenesis, implies an upper
bound on the masses of superparticles. In the case of broken R-parity the
constraints from primordial nucleosynthesis are naturally satisfied and
decaying gravitinos lead to characteristic signatures in high energy cosmic
rays. We analyse the implications for supergravity models with universal
boundary conditions at the grand unification scale. Together with low-energy
observables one obtains a window of superparticle masses, which will soon be
probed at the LHC, and a range of allowed reheating temperatures.


title: Faceted Ranking of Egos in Collaborative Tagging Systems

abstract:
  Multimedia uploaded content is tagged and recommended by users of
collaborative systems, resulting in informal classifications also known as
folksonomies. Faceted web ranking has been proved a reasonable alternative to a
single ranking which does not take into account a personalized context. In this
paper we analyze the online computation of rankings of users associated to
facets made up of multiple tags. Possible applications are user reputation
evaluation (ego-ranking) and improvement of content quality in case of
retrieval. We propose a solution based on PageRank as centrality measure: (i) a
ranking for each tag is computed offline on the basis of the corresponding
tag-dependent subgraph; (ii) a faceted order is generated by merging rankings
corresponding to all the tags in the facet. The fundamental assumption,
validated by empirical observations, is that step (i) is scalable. We also
present algorithms for part (ii) having time complexity O(k), where k is the
number of tags in the facet, well suited to online computation.


title: Algebraic K-theory of toric hypersurfaces

abstract:
  We construct classes in the motivic cohomology of certain 1-parameter
families of Calabi-Yau hypersurfaces in toric Fano n-folds, with applications
to local mirror symmetry (growth of genus 0 instanton numbers) and
inhomogeneous Picard-Fuchs equations. In the case where the family is
classically modular the classes are related to Belinson's Eisenstein symbol;
the Abel-Jacobi map (or rational regulator) is computed in this paper for both
kinds of cycles. For the "modular toric" families where the cycles essentially
coincide, we obtain a motivic (and computationally effective) explanation of a
phenomenon observed by Villegas, Stienstra, and Bertin.


title: Combination of Single Top Quark Production Results from CDF

abstract:
  Recently, the CDF experiment at the Fermilab Tevatron has used complementary
methods to make multiple measurements of the singly produced top quark cross
section. All analyses use the same dataset with more than 2 fb^-1 of CDF data
and event selection based on W+2 or W+3 jet events with at least one b-tagged
jet. However, due to differences in analysis techniques these results are not
fully correlated and a combination provides improved experimental precision.
Two independent methods are used to combine the results. This combination
results in an improved measurement of the single top production cross section
and also the CKM matrix element V_tb.


title: Thermal Effects in the dynamics of disordered elastic systems

abstract:
  Many seemingly different macroscopic systems (magnets, ferroelectrics, CDW,
vortices,..) can be described as generic disordered elastic systems.
Understanding their static and dynamics thus poses challenging problems both
from the point of view of fundamental physics and of practical applications.
Despite important progress many questions remain open. In particular the
temperature has drastic effects on the way these systems respond to an external
force. We address here the important question of the thermal effect close to
depinning, and whether these effects can be understood in the analogy with
standard critical phenomena, analogy so useful to understand the zero
temperature case. We show that close to the depinning force temperature leads
to a rounding of the depinning transition and compute the corresponding
exponent. In addition, using a novel algorithm it is possible to study
precisely the behavior close to depinning, and to show that the commonly
accepted analogy of the depinning with a critical phenomenon does not fully
hold, since no divergent lengthscale exists in the steady state properties of
the line below the depinning threshold.


title: The Distances of SNRs Kes 69 and G21.5-0.9 from HI and 13CO Spectra

abstract:
  We obtain new HI and $^{13}$CO images around Supernova Remnants (SNR) Kes 69
and G21.5-0.9. By comparing HI spectra with $^{13}$CO emission spectra, we
significantly revise the kinematic distance for Kes 69 to $\sim$ 5.5 kpc, which
was 11.2 kpc, and refine the kinematic distance for G21.5-0.9 to ~4.8 kpc. For
Kes 69, the highest velocity of absorption is ~86 km/s and a prominent HI
emission feature at ~ 112 km/s has no respective absorption. These new results
suggest that Kes 69 is associated with a newly detected extended 1720 MHz OH
maser at velocity of ~85 km/s that originates from within the bright southern
radio shell of Kes 69. For G21.5-0.9, the highest velocity of absorption is ~67
km/s. The HI absorption spectra of the nearby bright source PMN J1832-1035 and
of Kes 69 show a common absorption feature at velocity of ~69 km/s, which is
not seen for G21.5-0.9. The resulting velocity of ~68 km/s gives the best
distance estimate of ~4.8 kpc for G21.5-0.9 and associated young pulsar
J1833-1034.


title: Elements and cyclic subgroups of finite order of the Cremona group

abstract:
  We give the classification of elements - respectively cyclic subgroups - of
finite order of the Cremona group, up to conjugation. Natural parametrisations
of conjugacy classes, related to fixed curves of positive genus, are provided.


title: Effect of impurities on pentacene island nucleation

abstract:
  Pentacenequinone (PnQ) impurities have been introduced into a pentacene
source material in a controlled manner to quantify the relative effects of the
impurity content on grain boundary structure and thin film nucleation. Atomic
force microscopy (AFM) has been employed to directly characterize films grown
using 0.0-7.5% PnQ by weight in the source material. Analysis of the
distribution of capture zones areas of submonolayer islands as a function of
impurity content shows that for large PnQ content the critical nucleus size for
forming a Pn island is smaller than for low PnQ content. This result indicates
a favorable energy for formation of Pn-PnQ complexes, which in turn suggests
that the primary effect of PnQ on Pn mobility may arise from homogeneous
distribution of PnQ defects.


title:
Abstract composition rule for relativistic kinetic energy in the
  thermodynamical limit

abstract:
  We demonstrate by simple mathematical considerations that a power-law tailed
distribution in the kinetic energy of relativistic particles can be a limiting
distribution seen in relativistic heavy ion experiments. We prove that the
infinite repetition of an arbitrary composition rule on an infinitesimal amount
leads to a rule with a formal logarithm. As a consequence the stationary
distribution of energy in the thermodynamical limit follows the composed
function of the Boltzmann-Gibbs exponential with this formal logarithm. In
particular, interactions described as solely functions of the relative
four-momentum squared lead to kinetic energy distributions of the
Tsallis-Pareto (cut power-law) form in the high energy limit.


title: Deconvolving oscillatory transients with a Kalman filter

abstract:
  This paper describes a method to filter oscillatory transients from
measurements of a time series which were at least an order of magnitude larger
than the signal to be measured. Based on a Kalman filter, it has an optimality
property and a natural scaling parameter that allows to tune it to high
resolution or low noise.


title: Approaching the event horizon: 1.3mm VLBI of SgrA*

abstract:
  Advances in VLBI instrumentation now allow wideband recording that
significantly increases the sensitivity of short wavelength VLBI observations.
Observations of the super-massive black hole candidate at the center of the
Milky Way, SgrA*, with short wavelength VLBI reduces the scattering effects of
the intervening interstellar medium, allowing observations with angular
resolution comparable to the apparent size of the event horizon of the putative
black hole. Observations in April 2007 at a wavelength of 1.3mm on a three
station VLBI array have now confirmed structure in SgrA* on scales of just a
few Schwarzschild radii. When modeled as a circular Gaussian, the fitted
diameter of SgrA* is 37 micro arcsec (+16,-10; 3-sigma), which is smaller than
the expected apparent size of the event horizon of the Galactic Center black
hole. These observations demonstrate that mm/sub-mm VLBI is poised to open a
new window onto the study of black hole physics via high angular resolution
observations of the Galactic Center.


title: Examples of non integer dimensional geometries

abstract:
  Two examples of spectral triples with non-integer dimension spectrum are
considered. These triples involve commutative C*-algebras. The first example
has complex dimension spectrum and trivial differential algebra. The other is a
parameter dependent deformation of the canonical spectral triple over S1. Its
dimension spectrum includes real non-integer values. It has a non-trivial
differential algebra and in contrast with the one dimensional case there are no
junk forms for a non-vanishing deformation parameter. The distance on this
space depends non-trivially on this parameter.


title: Multistage Estimation of Bounded-Variable Means

abstract:
  In this paper, we develop a multistage approach for estimating the mean of a
bounded variable. We first focus on the multistage estimation of a binomial
parameter and then generalize the estimation methods to the case of general
bounded random variables. A fundamental connection between a binomial parameter
and the mean of a bounded variable is established. Our multistage estimation
methods rigorously guarantee prescribed levels of precision and confidence.


title: {Spin polarization tuning in Mn$_{x}$Fe$_{1-x}$Ge$_{3}$

abstract:
  Experimentally, the intermetallic compound Mn$_{4}$FeGe$_{3}$ has been
recently shown to exhibit enhanced magnetic properties and spin polarization
compared to the Mn$_{5}$Ge$_{3}$ parent compound. The present {\em ab-initio}
study focusses on the effect of Fe substitution on the electronic and magnetic
properties of the compound. Our calculations reveal that the changes on the
Fermi surface of the doped compound are remarkable and provide explanations for
the enhanced spin-polarization observed. Finally, we show that it is indeed
possible to tune the degree of spin-polarization upon Fe doping, thus making
the Mn$_{1-x}$Fe$_{x}$Ge$_{3}$ intermetallic alloy very promising for future
spintronic applications.


title: New Calabi-Yau Manifolds with Small Hodge Numbers

abstract:
  It is known that many Calabi-Yau manifolds form a connected web. The question
of whether all Calabi-Yau manifolds form a single web depends on the degree of
singularity that is permitted for the varieties that connect the distinct
families of smooth manifolds. If only conifolds are allowed then, since
shrinking two-spheres and three-spheres to points cannot affect the fundamental
group, manifolds with different fundamental groups will form disconnected webs.
We examine these webs for the tip of the distribution of Calabi-Yau manifolds
where the Hodge numbers (h^{11}, h^{21}) are both small. In the tip of the
distribution the quotient manifolds play an important role. We generate via
conifold transitions from these quotients a number of new manifolds. These
include a manifold with \chi =-6 and manifolds with an attractive structure
that may prove of interest for string phenomenology. We also examine the
relation of some of these manifolds to the remarkable Gross-Popescu manifolds
that have Euler number zero.


title: Brownian couplings, convexity, and shy-ness

abstract:
  Benjamini, Burdzy and Chen (2007) introduced the notion of a shy coupling: a
coupling of a Markov process such that, for suitable starting points, there is
a positive chance of the two component processes of the coupling staying a
positive distance away from each other for all time. Among other results, they
showed no shy couplings could exist for reflected Brownian motions in C^2
bounded convex planar domains whose boundaries contain no line segments. Here
we use potential-theoretic methods to extend this Benjamini et al. result (a)
to all bounded convex domains (whether planar and smooth or not) whose
boundaries contain no line segments, (b) to all bounded convex planar domains
regardless of further conditions on the boundary.


title:
Improved structural ordering in sexithiophene thick films grown on
  single crystal oxide substrates

abstract:
  We report on sexithiophene films, about 150nm thick, grown by thermal
evaporation on single crystal oxides and, as comparison, on Si/SiO2. By heating
the entire deposition chamber at 100 C we obtain standing-up oriented molecules
all over the bulk thickness. Surface morphology shows step-like islands, each
step being only one monolayer height. The constant and uniform warming of the
molecules obtained by heating the entire deposition chamber allows a stable
diffusion-limited growth process. Therefore, the regular growth kinetic is
preserved when increasing the thickness of the film. Electrical measurements on
differently structured films evidence the impact of the inter island separation
region size on the main charge transport parameters.


title:
Cold nuclear matter effects on J/psi production: intrinsic and extrinsic
  transverse momentum effects

abstract:
  Cold nuclear matter effects on J/psi production in proton-nucleus and
nucleus-nucleus collisions are evaluated taking into account the specific J/psi
production kinematics at the partonic level, the shadowing of the initial
parton distributions and the absorption in the nuclear matter. We consider two
different parton processes for the c-cbar pair production: one with collinear
gluons and a recoiling gluon in the final state and the other with initial
gluons carrying intrinsic transverse momentum. Our results are compared to RHIC
observables. The smaller values of the nuclear modification factor R_AA in the
forward rapidity region (with respect to the mid rapidity region) are partially
explained, therefore potentially reducing the need for recombination effects.