title: Spiral density wave triggering of star formation in SA and SAB galaxies

abstract:
  Azimuthal color (age) gradients across spiral arms are one of the main
predictions of density wave theory; gradients are the result of star formation
triggering by the spiral waves. In a sample of 13 spiral galaxies of types A
and AB, we find that 10 of them present regions that match the theoretical
predictions. By comparing the observed gradients with stellar population
synthesis models, the pattern speed and the location of major resonances have
been determined. The resonance positions inferred from this analysis indicate
that 9 of the objects have spiral arms that extend to the outer Lindblad
resonance (OLR); for one of the galaxies, the spiral arms reach the corotation
radius. The effects of dust, and of stellar densities, velocities, and
metallicities on the color gradients are also discussed.


title: A New Method for Knowledge Representation in Expert System's (XMLKR)

abstract:
  Knowledge representation it is an essential section of a Expert Systems,
Because in this section we have a framework to establish an expert system then
we can modeling and use by this to design an expert system. Many method it is
exist for knowledge representation but each method have problems, in this paper
we introduce a new method of object oriented by XML language as XMLKR to
knowledge representation, and we want to discuss advantage and disadvantage of
this method.


title: A novel method for the absolute fluorescence yield measurement by AIRFLY

abstract:
  One of the goals of the AIRFLY (AIR FLuorescence Yield) experiment is to
measure the absolute fluorescence yield induced by electrons in air to better
than 10% precision. We introduce a new technique for measurement of the
absolute fluorescence yield of the 337 nm line that has the advantage of
reducing the systematic uncertainty due to the detector calibration. The
principle is to compare the measured fluorescence yield to a well known process
- the Cerenkov emission. Preliminary measurements taken in the BFT (Beam Test
Facility) in Frascati, Italy with 350 MeV electrons are presented. Beam tests
in the Argonne Wakefield Accelerator at the Argonne National Laboratory, USA
with 14 MeV electrons have also shown that this technique can be applied at
lower energies.


title: Exact Stochastic Mean-Field dynamics

abstract:
  The exact evolution of a system coupled to a complex environment can be
described by a stochastic mean-field evolution of the reduced system density.
The formalism developed in Ref. [D.Lacroix, Phys. Rev. E77, 041126 (2008)] is
illustrated in the Caldeira-Leggett model where a harmonic oscillator is
coupled to a bath of harmonic oscillators. Similar exact reformulation could be
used to extend mean-field transport theories in Many-body systems and
incorporate two-body correlations beyond the mean-field one. The connection
between open quantum system and closed many-body problem is discussed.


title: Time management in a Poisson fishing model

abstract:
  The aim of the paper is to extend the model of "fishing problem". The simple
formulation is following. The angler goes to fishing. He buys fishing ticket
for a fixed time. There are two places for fishing at the lake. The fishes are
caught according to renewal processes which are different at both places. The
fishes' weights and the inter-arrival times are given by the sequences of
i.i.d. random variables with known distribution functions. These distributions
are different for the first and second fishing place. The angler's satisfaction
measure is given by difference between the utility function dependent on size
of the caught fishes and the cost function connected with time. On each place
the angler has another utility functions and another cost functions. In this
way, the angler's relative opinion about these two places is modeled. For
example, on the one place better sort of fish can be caught with bigger
probability or one of the places is more comfortable. Obviously our angler
wants to have as much satisfaction as possible and additionally he have to
leave the lake before the fixed moment. Therefore his goal is to find two
optimal stopping times in order to maximize his satisfaction. The first time
corresponds to the moment, when he eventually should change the place and the
second time, when he should stop fishing. These stopping times have to be less
than the fixed time of fishing. The value of the problem and the optimal
stopping times are derived.


title: Cosmological Perturbations at Second Order and Recombination Perturbed

abstract:
  We derive the full set of second-order equations governing the evolution of
cosmological perturbations, including the effects of the first-order electron
number density perturbations, \delta_e. We provide a detailed analysis of the
perturbations to the recombination history of the universe and show that a
perturbed version of the Peebles effective 3-level atom is sufficient for
obtaining the evolution of \delta_e for comoving wavenumbers smaller than
1Mpc^{-1}. We calculate rigorously the perturbations to the Ly\alpha escape
probability and show that to a good approximation it is governed by the local
baryon velocity divergence. For modes shorter than the photon diffusion scale,
we find that \delta_e is enhanced during recombination by a factor of roughly 5
relative to other first-order quantities sourcing the CMB anisotropies at
second order. Using these results, in a companion paper we calculate the CMB
bispectrum generated during recombination.


title:
Ground state energy of dilute neutron matter at next-to-leading order in
  lattice chiral effective field theory

abstract:
  We present lattice calculations for the ground state energy of dilute neutron
matter at next-to-leading order in chiral effective field theory. This study
follows a series of recent papers on low-energy nuclear physics using chiral
effective field theory on the lattice. In this work we introduce an improved
spin- and isospin-projected leading-order action which allows for a
perturbative treatment of corrections at next-to-leading order and smaller
estimated errors. Using auxiliary fields and Euclidean-time projection Monte
Carlo, we compute the ground state of 8, 12, and 16 neutrons in a periodic
cube, covering a density range from 2% to 10% of normal nuclear density.


title: Updating schemes in zero-temperature single-spin flip dynamics

abstract:
  In this paper we examine the role of the so called $c$-parallel updating
schemes in relaxation from disordered states to the final ferromagnetic steady
state. We investigate two zero-temperature single-spin flip dynamics on a one
dimensional lattice of length $L$: inflow (i.e. generalized zero-temperature
Glauber dynamics) and outflow opinion dynamics. The varying $c$ allows us to
change the updating scheme from random sequential updating ($c=1/L$) to
deterministic synchronous updating (for $c=1$). We show how the mean relaxation
times depend on $c$ and scale with the system size $L$. Moreover, we
empirically find an analytical formula for the ratio between mean relaxation
times for inflow and outflow dynamics. Results obtained in this paper suggest
that in some sense the original zero-temperature Glauber dynamics is a critical
one among a broader class of inflow dynamics.


title: Walking Dynamics from String Duals

abstract:
  Within the context of a String Theory dual to N=1 gauge theories with gauge
group SU(Nc) and large Nc, we identify a class of solutions of the background
equations for which a suitably defined dual of the gauge coupling exhibits the
features of a walking theory. We find evidence for three distinct, dynamically
generated scales, characterizing walking, symmetry breaking and confinement,
and we put them in correspondence with field theory by an analysis of the
operators driving the flow.


title:
Nickel-Rich Outflows from Accretion Disks Formed by the
  Accretion-Induced Collapse of White Dwarfs

abstract:
  A white dwarf (WD) approaching the Chandrasekhar mass may in several cases
undergo accretion-induced collapse (AIC) to a neutron star (NS) before a
thermonuclear explosion ensues. It has generally been assumed that AIC does not
produce a detectable supernova (SN). If, however, the progenitor WD is rapidly
rotating (as may be expected due to its prior accretion), a centrifugally
supported disk forms around the NS upon collapse. We calculate the subsequent
evolution of this accretion disk using time-dependent height-integrated
simulations with initial conditions taken from the AIC calculations of Dessart
et al. (2006). Initially, the disk is cooled by neutrinos and its composition
is driven neutron-rich (electron fraction Ye ~ 0.1) by electron captures.
However, as the disk viscously spreads, it is irradiated by neutrinos from the
central proto-NS, which dramatically alters its neutron-to-proton ratio. We
find that electron neutrino captures increase Ye to ~ 0.5 by the time that weak
interactions in the disk freeze out. Because the disk becomes radiatively
inefficient and begins forming alpha-particles soon after freeze out, powerful
winds blow away most of the disk's remaining mass. These Ye ~ 0.5 outflows
synthesize up to a few times 1e-2 Msun in 56Ni. As a result, AIC may be
accompanied by a radioactively powered SN-like transient that peaks on a
timescale of ~ 1 day. Since few intermediate mass elements are likely
synthesized, these Ni-rich explosions should be spectroscopically distinct from
other SNe. PanSTARRs and the Palomar Transient Factory should detect a few AIC
transients per year if their true rate is ~1/100 of the Type Ia rate, and LSST
should detect hundreds per year. High cadence observations (< 1 day) are
optimal for the detection and follow-up of AIC (abridged).


title:
The SU(N) Heisenberg model on the square lattice: a continuous-N quantum
  Monte Carlo study

abstract:
  A quantum phase transition is typically induced by tuning an external
parameter that appears as a coupling constant in the Hamiltonian. Another route
is to vary the global symmetry of the system, generalizing, e.g., SU(2) to
SU(N). In that case, however, the discrete nature of the control parameter
prevents one from identifying and characterizing the transition. We show how
this limitation can be overcome for the SU(N) Heisenberg model with the help of
a singlet projector algorithm that can treat N continuously. On the square
lattice, we find a direct, continuous phase transition between Neel-ordered and
crystalline bond-ordered phases at Nc=4.57(5) with critical exponents z=1 and
beta/nu=0.81(3).


title: Non-Gaussianities from Perturbing Recombination

abstract:
  We approximately compute the bispectrum induced on the CMB temperature by
fluctuations in the standard recombination epoch. Of all the second order
sources that can induce non-Gaussianity during recombination, we concentrate on
those proportional to the perturbation in the free electron density, which is
about a factor of 5 larger than the other first order perturbations. This term
induces some non-Gaussianity by delaying the time of recombination and by
changing the photon diffusion scale. We find that the signal is not scale
invariant, peaked on squeezed triangles with the smaller multipole around the
scale of the first acoustic peak, and that its size corresponds to an effective
f_NL ~ -3.5, which could be marginally detected by Planck if both temperature
and polarization are measured.


title:
Evolution of Dark Matter Phase-Space Density Distributions in Equal-Mass
  Halo Mergers

abstract:
  We use dissipationless N-body simulations to investigate the evolution of the
true coarse-grained phase-space density distribution f(x,v) in equal-mass
mergers between dark matter (DM) halos. The halo models are constructed with
various asymptotic power-law indices ranging from steep cusps to core-like
profiles and we employ the phase-space density estimator ``Enbid'' developed by
Sharma & Steinmetz to compute f(x,v). The adopted force resolution allows
robust phase-space density profile estimates in the inner ~1% of the virial
radii of the simulated systems. We confirm that mergers result in a decrease of
the coarse-grained phase-space density in accordance with expectations from
Mixing Theorems for collisionless systems. We demonstrate that binary mergers
between identical DM halos produce remnants that retain excellent memories of
the inner slopes and overall shapes of the phase-space density distribution of
their progenitors. The robustness of the phase-space density profiles holds for
a range of orbital energies, and a variety of encounter configurations
including sequences of several consecutive merger events, designed to mimic
hierarchical merging, and collisions occurring at different cosmological
epochs. If the progenitor halos are constructed with appreciably different
asymptotic power-law indices, we find that the inner slope and overall shape of
the phase-space density distribution of the remnant are substantially closer to
that of the initial system with the steepest central density cusp. These
results explicitly demonstrate that mixing is incomplete in equal-mass mergers
between DM halos, as it does not erase memory of the progenitor properties. Our
results also confirm the recent analytical predictions of Dehnen (2005)
regarding the preservation of merging self-gravitating central density cusps.


title: Alkaline-Earth-Metal Atoms as Few-Qubit Quantum Registers

abstract:
  We propose and analyze a novel approach to quantum information processing, in
which multiple qubits can be encoded and manipulated using electronic and
nuclear degrees of freedom associated with individual alkaline-earth atoms
trapped in an optical lattice. Specifically, we describe how the qubits within
each register can be individually manipulated and measured with sub-wavelength
optical resolution. We also show how such few-qubit registers can be coupled to
each other in optical superlattices via conditional tunneling to form a
scalable quantum network. Finally, potential applications to quantum
computation and precision measurements are discussed.


title: Minimal gauged U(1)_{B-L} model with spontaneous R-parity violation

abstract:
  We study the minimal gauged U(1)_{B-L} supersymmetric model and show that it
provides an attractive theory for spontaneous R-parity violation. Both
U(1)_{B-L} and R-parity are broken by the vacuum expectation value of the
right-handed sneutrino (proportional to the soft SUSY masses), thereby linking
the B-L and soft SUSY scales. In this context we find a consistent mechanism
for generating neutrino masses and a realistic mass spectrum, all without
extending the Higgs sector of the minimal supersymmetry standard model. We
discuss the most relevant collider signals and the connection between the Z'
gauge boson and R-parity violation.


title:
Methods and results of an automatic analysis of a complete sample of
  Swift-XRT observations of GRBs

abstract:
  We present a homogeneous X-ray analysis of all 318 Gamma Ray Bursts detected
by the X-ray Telescope on the Swift satellite up to 2008 July 23; this
represents the largest sample of X-ray GRB data published to date. In Sections
2--3 we detail the methods which the Swift-XRT team has developed to produce
the enhanced positions, light curves, hardness ratios and spectra presented in
this paper. Software using these methods continues to create such products for
all new GRBs observed by the Swift-XRT. We also detail web-based tools allowing
users to create these products for any object observed by the XRT, not just
GRBs. In Sections 4--6 we present the results of our analysis of GRBs,
including probability distribution functions of the temporal and spectral
properties of the sample. We demonstrate evidence for a consistent underlying
behaviour which can produce a range of light curve morphologies, and attempt to
interpret this behaviour in the framework of external forward shock emission.
We find several difficulties, in particular that reconciliation of our data
with the forward shock model requires energy injection to continue for days to
weeks.


title: Discreteness of area in noncommutative space

abstract:
  We introduce an area operator for the Moyal noncommutative plane. We find
that the spectrum is discrete, but, contrary to the expectation formulated by
other authors, not characterized by a "minimum-area principle". We show that an
intuitive analysis of the uncertainty relations obtained from Moyal-plane
noncommutativity is fully consistent with our results for the spectrum, and we
argue that our area operator should be generalizable to several other
noncommutative spaces. We also observe that the properties of distances and
areas in the Moyal plane expose some weaknesses in the line of reasoning
adopted in some of the heuristic analyses of the measurability of geometric
spacetime observables in the quantum-gravity realm.


title: Lack of PAH emission toward low-mass embedded young stellar objects

abstract:
  PAHs have been detected toward molecular clouds and some young stars with
disks, but have not yet been associated with embedded young stars. We present a
sensitive mid-IR spectroscopic survey of PAH features toward a sample of
low-mass embedded YSOs. The aim is to put constraints on the PAH abundance in
the embedded phase of star formation using radiative transfer modeling.
  VLT-ISAAC L-band spectra for 39 sources and Spitzer IRS spectra for 53
sources are presented. Line intensities are compared to recent surveys of
Herbig Ae/Be and T Tauri stars. The radiative transfer codes RADMC and RADICAL
are used to model the PAH emission from embedded YSOs consisting of a PMS star
with a circumstellar disk embedded in an envelope. The dependence of the PAH
feature on PAH abundance, stellar radiation field, inclination and the
extinction by the surrounding envelope is studied.
  The 3.3 micron PAH feature is undetected for the majority of the sample
(97%), with typical upper limits of 5E-16 W/m^2. Compact 11.2 micron PAH
emission is seen directly towards 1 out of the 53 Spitzer Short-High spectra,
for a source that is borderline embedded. For all 12 sources with both VLT and
Spitzer spectra, no PAH features are detected in either. In total, PAH features
are detected toward at most 1 out of 63 (candidate) embedded protostars (<~
2%), even lower than observed for class II T Tauri stars with disks (11-14%).
Assuming typical class I stellar and envelope parameters, the absence of PAHs
emission is most likely explained by the absence of emitting carriers through a
PAH abundance at least an order of magnitude lower than in molecular clouds but
similar to that found in disks. Thus, most PAHs likely enter the protoplanetary
disks frozen out in icy layers on dust grains and/or in coagulated form.


title: Grid Diagrams, Braids, and Contact Geometry

abstract:
  We use grid diagrams to present a unified picture of braids, Legendrian
knots, and transverse knots.


title: Ultraspherical type generating functions for orthogonal polynomials

abstract:
  We characterize, up to a conjecture, probability distributions of all order
finite moments having ultraspherical type generating functions for orthogonal
polynomials.


title: Spectrum conditions for symmetric extendible states

abstract:
  We analyze bipartite quantum states that admit a symmetric extension. Any
such state can be decomposed into a convex combination of states that allow a
_pure_ symmetric extension. A necessary condition for a state to admit a pure
symmetric extension is that the spectra of the local and global density
matrices are equal. This condition is also sufficient for two qubits, but not
for any larger systems. Using this condition we present a conjectured necessary
and sufficient condition for a two qubit state to admit symmetric extension,
which we prove in some special cases. The results from symmetric extension
carry over to degradable and anti-degradable channels and we use this to prove
that all degradable channels with qubit output have a qubit environment.


title: Exploring General Gauge Mediation

abstract:
  We explore various aspects of General Gauge Mediation(GGM). We present a
reformulation of the correlation functions used in GGM, and further elucidate
their IR and UV properties. Additionally we clarify the issue of UV sensitivity
in the calculation of the soft masses in the MSSM, highlighting the role of the
supertrace over the messenger spectrum. Finally, we present weakly coupled
messenger models which fully cover the parameter space of GGM. These examples
demonstrate that the full parameter space of GGM is physical and realizable.
Thus it should be considered a valid basis for future phenomenological
explorations of gauge mediation.


title:
Enabling Next Generation Dark Energy and Epoch of Reionization Radio
  Observatories with the MOFF Correlator

abstract:
  Proposed 21 cm cosmology observatories for studying the epoch of reionization
(z ~6-15) and dark energy (z ~0-6) envision compact arrays with tens of
thousands of antenna elements. Fully correlating this many elements is
computationally expensive using traditional XF or FX correlators, and has led
some groups to reconsider direct imaging/FFT correlators. In this paper we
develop a variation of the direct imaging correlator we call the MOFF
correlator. The MOFF correlator shares the computational advantages of a direct
imaging correlator, while avoiding a number of its shortcomings. In particular
the MOFF correlator makes no constraints on the antenna arrangement or type,
provides a fully calibrated output image including widefield polarimetry and
non-coplanar baseline effects, and can be orders-of-magnitude more efficient
than XF or FX correlators for compact radio cosmology arrays.


title: On the period map for prime Fano threefolds of degree 10

abstract:
  We prove that the deformations of a smooth complex Fano threefold X with
Picard number 1, index 1, and degree 10, are unobstructed. The differential of
the period map has two-dimensional kernel. We construct two two-dimensional
components of the fiber of the period map through X: one is isomorphic to the
variety of conics in X, modulo an involution, another is birationally
isomorphic to a moduli space of semistable rank-2 torsion-free sheaves on X,
modulo an involution. The threefolds corresponding to points of these
components are obtained from X via conic and line (birational) transformations.


title:
Regularized Multivariate Regression for Identifying Master Predictors
  with Application to Integrative Genomics Study of Breast Cancer

abstract:
  In this paper, we propose a new method remMap -- REgularized Multivariate
regression for identifying MAster Predictors -- for fitting multivariate
response regression models under the high-dimension-low-sample-size setting.
remMap is motivated by investigating the regulatory relationships among
different biological molecules based on multiple types of high dimensional
genomic data. Particularly, we are interested in studying the influence of DNA
copy number alterations on RNA transcript levels. For this purpose, we model
the dependence of the RNA expression levels on DNA copy numbers through
multivariate linear regressions and utilize proper regularizations to deal with
the high dimensionality as well as to incorporate desired network structures.
Criteria for selecting the tuning parameters are also discussed. The
performance of the proposed method is illustrated through extensive simulation
studies. Finally, remMap is applied to a breast cancer study, in which genome
wide RNA transcript levels and DNA copy numbers were measured for 172 tumor
samples. We identify a tran-hub region in cytoband 17q12-q21, whose
amplification influences the RNA expression levels of more than 30 unlinked
genes. These findings may lead to a better understanding of breast cancer
pathology.


title:
Asymptotics for random Young diagrams when the word length and alphabet
  size simultaneously grow to infinity

abstract:
  Given a random word of size $n$ whose letters are drawn independently from an
ordered alphabet of size $m$, the fluctuations of the shape of the random RSK
Young tableaux are investigated, when $n$ and $m$ converge together to
infinity. If $m$ does not grow too fast and if the draws are uniform, then the
limiting shape is the same as the limiting spectrum of the GUE. In the
non-uniform case, a control of both highest probabilities will ensure the
convergence of the first row of the tableau toward the Tracy--Widom
distribution.


title: The magnetic field structure in NGC 253 in presence of a galactic wind

abstract:
  We present radio continuum polarimetry observations of the nearby edge-on
galaxy NGC 253 which possesses a very bright radio halo. Using the vertical
synchrotron emission profiles and the lifetimes of cosmic-ray electrons, we
determined the cosmic-ray bulk speed as (300+/-30) km/s, indicating the
presence of a galactic wind in this galaxy. The large-scale magnetic field was
decomposed into a toroidal axisymmetric component in the disk and a poloidal
component in the halo. The poloidal component shows a prominent X-shaped
magnetic field structure centered on the nucleus, similar to the magnetic field
observed in other edge-on galaxies. Faraday rotation measures indicate that the
poloidal field has an odd parity (antisymmetric). NGC 253 offers the
possibility to compare the magnetic field structure with models of galactic
dynamos and/or galactic wind flows.


title: Monge-Amp\`ere equations in big cohomology classes

abstract:
  We define non-pluripolar products of closed positive currents on a compact
Kaehler manifold. We show that a positive non-pluripolar measure can be written
in a unique way as the top degree self-intersection (in the non-pluripolar
sense) of a closed positive current in given big cohomology class. The solution
is shown to have minimal singularities in the sense of Demailly if the measure
is regular enough. These results are combined with a fixed point argument to
construct singular Kaehler-Einstein volume forms with minimal singularities on
varieties of general type.


title: Space-Efficient Simulation of Quantum Computers

abstract:
  Traditional algorithms for simulating quantum computers on classical ones
require an exponentially large amount of memory, and so typically cannot
simulate general quantum circuits with more than about 30 or so qubits on a
typical PC-scale platform with only a few gigabytes of main memory. However,
more memory-efficient simulations are possible, requiring only polynomial or
even linear space in the size of the quantum circuit being simulated. In this
paper, we describe one such technique, which was recently implemented at FSU in
the form of a C++ program called SEQCSim, which we releasing publicly. We also
discuss the potential benefits of this simulation in quantum computing research
and education, and outline some possible directions for further progress.


title:
Microwave frequency modulation in continuous-wave far-infrared ESR
  utilizing a quasioptical reflection bridge

abstract:
  We report the development of the frequency-modulation (FM) method for
measuring electron spin resonance (ESR) absorption in the 210-420 GHz frequency
range. We demonstrate that using a high-frequency ESR spectrometer without
resonating microwave components enables us to overcome technical difficulties
associated with the FM method due to nonlinear microwave-elements, without
sacrificing spectrometer performance. FM was achieved by modulating the
reference oscillator of a 13 GHz Phase Locked Dielectric Resonator Oscillator,
and amplifying and frequency-multiplying the resulting millimeter-wave
radiation up to 210, 315 and 420 GHz. ESR spectra were obtained in reflection
mode by a lock-in detection at the fundamental modulation frequency, and also
at the second and third harmonic. Sensitivity of the setup was verified by
conduction electron spin resonance measurement in KC$_{60}$.


title: Artificial intelligence for Bidding Hex

abstract:
  We present a Monte Carlo algorithm for efficiently finding near optimal moves
and bids in the game of Bidding Hex. The algorithm is based on the recent
solution of Random-Turn Hex by Peres, Schramm, Sheffield, and Wilson together
with Richman's work connecting random-turn games to bidding games.


title: Intersections on tropical moduli spaces

abstract:
  This article explores to which extent the algebro-geometric theory of
rational descendant Gromov-Witten invariants can be carried over to the
tropical world. Despite the fact that the tropical moduli-spaces we work with
are non-compact, the answer is surprisingly positive. We discuss the string,
divisor and dilaton equations, we prove a splitting lemma describing the
intersection with a "boundary" divisor and we prove general tropical versions
of the WDVV resp. topological recursion equations (under some assumptions). As
a direct application, we prove that the toric varieties $\mathbb{P}^1$,
$\mathbb{P}^2$, $\mathbb{P}^1 \times \mathbb{P}^1$ and with Psi-conditions only
in combination with point conditions, the tropical and classical descendant
Gromov-Witten invariants coincide (which extends the result for $\mathbb{P}^2$
in Markwig-Rau-2008). Our approach uses tropical intersection theory and can
unify and simplify some parts of the existing tropical enumerative geometry
(for rational curves).


title: Predictability in Spatially Extended Systems with Model Uncertainty

abstract:
  Macroscopic models for spatially extended systems under random influences are
often described by stochastic partial differential equations (SPDEs).
  Some techniques for understanding solutions of such equations, such as
estimating correlations, Liapunov exponents and impact of noises, are
discussed. They are relevant for understanding predictability in spatially
extended systems with model uncertainty, for example, in physics, geophysics
and biological sciences. The presentation is for a wide audience.


title:
Symplectic forms and cohomology decomposition of almost complex
  4-manifolds

abstract:
  For any compact almost complex manifold $(M,J)$, the last two authors defined
two subgroups $H_J^+(M)$, $H_J^-(M)$ of the degree 2 real de Rham cohomology
group $H^2(M, \mathbb{R})$ in arXiv:0708.2520. These are the sets of cohomology
classes which can be represented by $J$-invariant, respectively,
$J$-anti-invariant real $2-$forms. In this note, it is shown that in dimension
4 these subgroups induce a cohomology decomposition of $H^2(M, \mathbb{R})$.
This is a specifically 4-dimensional result, as it follows from a recent work
of Fino and Tomassini. Some estimates for the dimensions of these groups are
also established when the almost complex structure is tamed by a symplectic
form and an equivalent formulation for a question of Donaldson is given.


title: Valley Degeneracies in (111) Silicon Quantum Wells

abstract:
  (111) Silicon quantum wells have been studied extensively, yet no convincing
explanation exists for the experimentally observed breaking of 6 fold valley
degeneracy into 2 and 4 fold degeneracies. Here, systematic sp3d5s*
tight-binding and effective mass calculations are presented to show that a
typical miscut modulates the energy levels which leads to breaking of 6 fold
valley degeneracy into 2 lower and 4 raised valleys. An effective mass based
valley-projection model is used to determine the directions of valley-minima in
tight-binding calculations of large supercells. Tight-binding calculations are
in better agreement with experiments compared to effective mass calculations.


title:
Submillimeter Continuum Properties of Cold Dust in the Inner Disk and
  Outflows of M82

abstract:
  Deep submillimeter (submm) continuum imaging observations of the starburst
galaxy M82 are presented at 350, 450, 750 and 850 micron wavelengths, that were
undertaken with the Submillimetre Common-User Bolometer Array (SCUBA) on the
James Clerk Maxwell Telescope in Hawaii. The presented maps include a
co-addition of submm data mined from the SCUBA Data Archive. The co-added data
produce the deepest submm continuum maps yet of M82, in which low-level 850
micron continuum has been detected out to 1.5kpc, at least 10% farther in
radius than any previously published submm detections of this galaxy. The
overall submm morphology and spatial spectral energy distribution of M82 have a
general north-south asymmetry consistent with H-alpha and X-ray winds,
supporting the association of the extended continuum with outflows of dust
grains from the disk into the halo. The new data raise interesting points about
the origin and structure of the submm emission in the inner disk of M82. In
particular, SCUBA short wavelength evidence of submm continuum peaks that are
asymmetrically distributed along the galactic disk suggests the inner-disk
emission is re-radiation from dust concentrations along a bar (or perhaps a
spiral) rather than edges of a dust torus, as is commonly assumed. Higher
resolution submm interferometery data from the Smithsonian Submillimeter Array
and later Atacama Large Millimeter Array should spatially resolve and further
constrain the reported dust emission structures in M82.


title:
The London penetration depth in single crystals of
  Ba(Fe_{1-x}Co_x)_2As_2 at various doping levels

abstract:
  The London penetration depth $\lambda(T)$ has been measured in single
crystals of Ba(Fe$_{1-x}$Co$_{x}$)$_{2}$As$_{2}$ using the tunnel diode
resonator technique. The measured doping levels of $x=$~0.038, 0.047, 0.058,
0.074 and 0.10 range from underdoped to overdoped concentrations. The
measurements have shown that the density of carriers participating in
superconductivity decreases sharply in the underdoped regime, but the
penetration depth as a function of temperature exhibits a robust power law,
$\Delta\lambda(T)\sim T^{n}$, for all measured dopings, with $n$ between 2 and
2.5. We discuss the implications of these results and possible interpretations
of such robust behavior.


title: Loop groups and holomorphic bundles

abstract:
  This paper considers the links between the geometry of the various flag
manifolds of loop groups and bundles over families of rational curves. Aa an
application, a stability result for the moduli on a rational ruled surface of
G-bundles with additional flag structure along a line is proven for any
reductive group; this gives the corresponding stability statement for any
compact group K for the moduli of K-instantons over the four-sphere, and for
the moduli of K-calorons over the three-sphere times the circle. The paper also
considers the Hecke transforms on bundles induced by outer automorphisms of the
loop groups.


title:
Adiabatic dynamics of a quantum critical system coupled to an
  environment: Scaling and kinetic equation approaches

abstract:
  We study the dynamics of open quantum many-body systems driven across a
critical point by quenching an Hamiltonian parameter at a certain velocity.
General scaling laws are derived for the density of excitations and energy
produced during the quench as a function of quench velocity and bath
temperature. The scaling laws and their regimes of validity are verified for
the XY spin chain locally coupled to bosonic baths. A detailed derivation and
analysis of the kinetic equation of the problem is presented.


title:
Direct numerical integration of one-loop Feynman diagrams for N-photon
  amplitudes

abstract:
  One approach to the calculation of cross sections for infrared-safe
observables in high energy collisions at next-to-leading order is to perform
all of the integrations, including the virtual loop integration, by Monte Carlo
numerical integration. In a previous paper, two of us have shown how one can
perform such a virtual loop integration numerically after first introducing a
Feynman parameter representation. In this paper, we perform the integration
directly, without introducing Feynman parameters, after suitably deforming the
integration contour. Our example is the N-photon scattering amplitude with a
massless electron loop. We report results for N = 6 and N = 8.


title: On multivariate Newton-like inequalities

abstract:
  We study multivariate entire functions and polynomials with non-negative
coefficients. A class of {\bf Strongly Log-Concave} entire functions,
generalizing {\it Minkowski} volume polynomials, is introduced: an entire
function $f$ in $m$ variables is called {\bf Strongly Log-Concave} if the
function $(\partial x_1)^{c_1}...(\partial x_m)^{c_m} f$ is either zero or
$\log((\partial x_1)^{c_1}...(\partial x_m)^{c_m} f)$ is concave on
$R_{+}^{m}$. We start with yet another point of view (via {\it propagation}) on
the standard univarite (or homogeneous bivariate) {\bf Newton Inequlities}. We
prove analogues of (univariate) {\bf Newton Inequlities} in the (multivariate)
{\bf Strongly Log-Concave} case. One of the corollaries of our new Newton(like)
inequalities is the fact that the support $supp(f)$ of a {\bf Strongly
Log-Concave} entire function $f$ is discretely convex ($D$-convex in our
notation). The proofs are based on a natural convex relaxation of the
derivatives $Der_{f}(r_1,...,r_m)$ of $f$ at zero and on the lower bounds on
$Der_{f}(r_1,...,r_m)$, which generalize the {\bf Van Der
Waerden-Falikman-Egorychev} inequality for the permanent of doubly-stochastic
matrices. A few open questions are posed in the final section.


title:
HNCO abundances in galaxies: Tracing the evolutionary state of
  starbursts

abstract:
  The chemistry in the central regions of galaxies is expected to be strongly
influenced by their nuclear activity. To find the best tracers of nuclear
activity is of key importance to understand the processes taking place in the
most obscured regions of galactic nuclei. In this work we present multi-line
observations of CS, C34S, HNCO and C18O in a sample of 11 bright galaxies
prototypical for different types of activity. The 32S/34S isotopic ratio is
~10, supporting the idea of an isotopical 34S enrichment due to massive star
formation in the nuclear regions of galaxies. Although C32S and C34S do not
seem to be significantly affected by the activity type, the HNCO abundance
appears highly contrasted among starburst. We observed HNCO abundance
variations of nearly two orders of magnitude. The HNCO molecule is shown to be
a good tracer of the amount of molecular material fueling the starburst and
therefore can be used as a diagnostics of the evolutionary state of a nuclear
starburst.


title:
Dicke-Type Energy Level Crossings in Cavity-Induced Atom Cooling:
  Another Superradiant Cooling

abstract:
  This paper is devoted to energy-spectral analysis for the system of a
two-level atom coupled with photons in a cavity. It is shown that the
Dicke-type energy level crossings take place when the atom-cavity interaction
of the system undergoes changes between the weak coupling regime and the strong
one. Using the phenomenon of the crossings we develop the idea of
cavity-induced atom cooling proposed by the group of Ritsch, and we lay
mathematical foundations of a possible mechanism for another superradiant
cooling in addition to that proposed by Domokos and Ritsch. The process of our
superradiant cooling can function well by cavity decay and by control of the
position of the atom, at least in (mathematical) theory, even if there is
neither atomic absorption nor atomic emission of photons.


title:
Fortran 90 implementation of the Hartree-Fock approach within the CNDO/2
  and INDO models

abstract:
  Despite the tremendous advances made by the ab initio theory of electronic
structure of atoms and molecules, its applications are still not possible for
very large systems. Therefore, semi-empirical model Hamiltonians based on the
zero-differential overlap (ZDO) approach such as the Pariser-Parr-Pople, CNDO,
INDO, etc. provide attractive, and computationally tractable, alternatives to
the ab initio treatment of large systems. In this paper we describe a Fortran
90 computer program developed by us, that uses CNDO/2 and INDO methods to solve
Hartree-Fock(HF) equation for molecular systems. The INDO method can be used
for the molecules containing the first-row atoms, while the CNDO/2 method is
applicable to those containing both the first-, and the second-row, atoms. We
have paid particular attention to computational efficiency while developing the
code, and, therefore, it allows us to perform calculations on large molecules
such as C_60 on small computers within a matter of seconds. Besides being able
to compute the molecular orbitals and total energies, our code is also able to
compute properties such as the electric dipole moment, Mulliken population
analysis, and linear optical absorption spectrum of the system. We also
demonstrate how the program can be used to compute the total energy per unit
cell of a polymer. The applications presented in this paper include small
organic and inorganic molecules, fullerene C_60, and model polymeric systems,
viz., chains containing alternating boron and nitrogen atoms (BN chain), and
carbon atoms (C chain).


title:
A New Family of Covariate-Adjusted Response Adaptive Designs and their
  Asymptotic Properties

abstract:
  It is often important to incorporating covariate information in the design of
clinical trials. In literature, there are many designs of using stratification
and covariate-adaptive randomization to balance on certain known covariate.
Recently Zhang, Hu, Cheung and Chan (2007) have proposed a family of
covariate-adjusted response-adaptive (CARA) designs and studied their
asymptotic properties. However, these CARA designs often have high
variabilities. In this paper, we propose a new family of covariate-adjusted
response-adaptive (CARA) designs. We show that the new designs have smaller
variabilities and therefore more efficient.


title: The Penrose Transform in the Split Signature

abstract:
  A version of the Penrose transform is introduced in the split signature. It
relates the cohomological data with supports on the open subsets of the complex
3-projective space and kernel of differential operators on the (real)
Grassmannian of 2-planes in the Euclidean 4-space. As an example we derive a
cohomological interpretation of the so-called X-ray transform. Furthermore, a
cohomological realization of the so-called "minimal" representation of SL(4,R)
is given. We also present the split Penrose transform in split instanton
backgrounds.


title:
Description of Four-Body Breakup Reaction with the Method of
  Continuum-Discretized Coupled-Channels

abstract:
  We present a method for smoothing discrete breakup $S$-matrix elements
calculated by the method of continuum-discretized coupled-channels (CDCC). This
smoothing method makes it possible to apply CDCC to four-body breakup
reactions. The reliability of the smoothing method is confirmed for two cases,
$^{58}$Ni($d$, $p n$) at 80 MeV and the $E1$ transition of $^6$He. We apply
CDCC with the smoothing method to $^6$He breakup reaction at 22.5 MeV.
Multi-step breakup processes are found to be important.


title:
On continuous variable quantum algorithms for oracle identification
  problems

abstract:
  We establish a framework for oracle identification problems in the continuous
variable setting, where the stated problem necessarily is the same as in the
discrete variable case, and continuous variables are manifested through a
continuous representation in an infinite-dimensional Hilbert space. We apply
this formalism to the Deutsch-Jozsa problem and show that, due to an
uncertainty relation between the continuous representation and its
Fourier-transform dual representation, the corresponding Deutsch-Jozsa
algorithm is probabilistic hence forbids an exponential speed-up, contrary to a
previous claim in the literature.


title:
Tripartite entanglement versus tripartite nonlocality in 3-qubit
  GHZ-class states

abstract:
  We analyze the relationship between tripartite entanglement and genuine
tripartite nonlocality for 3-qubit pure states in the GHZ class. We consider a
family of states known as the generalized GHZ states and derive an analytical
expression relating the 3-tangle, which quantifies tripartite entanglement, to
the Svetlichny inequality, which is a Bell-type inequality that is violated
only when all three qubits are nonlocally correlated. We show that states with
3-tangle less than 1/2 do not violate the Svetlichny inequality. On the other
hand, a set of states known as the maximal slice states do violate the
Svetlichny inequality, and exactly analogous to the two-qubit case, the amount
of violation is directly related to the degree of tripartite entanglement. We
discuss further interesting properties of the generalized GHZ and maximal slice
states.


title: Cavity-induced giant Kerr nonlinearities in a driven V-type atom

abstract:
  We discuss a simple and experimentally realizable model for creation of
enhanced Kerr nonlinearities accompanied by vanishing absorption. The model
involves a V-type atom subjected to a strong drive laser, a weak probe laser
and coupled to a single-mode cavity field. Working in the bad-cavity limit, we
find that the simultaneous coupling of the cavity field to both atomic
transitions creates a coherence between the transitions and thus can lead to
quantum interference effects. We investigate the influences of the cavity field
frequency, the cavity field-atom coupling constants and the atomic decay
constants on the linear and the third-order (Kerr) nonlinear susceptibilities.
We predict giant Kerr nonlinearities with vanishing absorption and attribute
this effect to the combination of the Purcell effect and the cavity-induced
quantum interference.


title:
The Gaussian approximation for multi-color generalized Friedman's urn
  model

abstract:
  The Friedman's urn model is a popular urn model which is widely used in many
disciplines. In particular, it is extensively used in treatment allocation
schemes in clinical trials. In this paper, we prove that both the urn
composition process and the allocation proportion process can be approximated
by a multi-dimensional Gaussian process almost surely for a multi-color
generalized Friedman's urn model with non-homogeneous generating matrices. The
Gaussian process is a solution of a stochastic differential equation. This
Gaussian approximation together with the properties of the Gaussian process is
important for the understanding of the behavior of the urn process and is also
useful for statistical inferences. As an application, we obtain the asymptotic
properties including the asymptotic normality and the law of the iterated
logarithm for a multi-color generalized Friedman's urn model as well as the
randomized-play-the-winner rule as a special case.


title: Immigrated urn models - asymptotic properties and applications

abstract:
  Urn models have been widely studied and applied in both scientific and social
science disciplines. In clinical studies, the adoption of urn models in
treatment allocation schemes has been proved to be beneficial to both
researchers, by providing more efficient clinical trials, and patients, by
increasing the likelihood of receiving the better treatment. In this paper, we
propose a new and general class of immigrated urn (IMU) models that
incorporates the immigration mechanism into the urn process. Theoretical
properties are developed and the advantages of the IMU models are discussed. In
general, the IMU models have smaller variabilities than the classical urn
models, yielding more powerful statistical inferences in applications.
  Illustrative examples are presented to demonstrate the wide applicability of
the IMU models. The proposed IMU framework, including many popular classical
urn models, not only offers a unify perspective for us to comprehend the urn
process, but also enables us to generate several novel urn models with
desirable properties.


title: Multi-color Randomly Reinforced Urn for Adaptive Designs

abstract: This paper is withdrawn


title:
Finite planar emulators for K_{4,5} - 4K_2 and K_{1,2,2,2} and Fellows'
  Conjecture

abstract:
  In 1988 Fellows conjectured that if a finite, connected graph admits a finite
planar emulator, then it admits a finite planar cover. We construct a finite
planar emulator for K_{4,5} - 4K_2. Archdeacon showed that K_{4,5} - 4K_2 does
not admit a finite planar cover; thus K_{4,5} - 4K_2 provides a counterexample
to Fellows' Conjecture.
  It is known that Negami's Planar Cover Conjecture is true if and only if
K_{1,2,2,2} admits no finite planar cover. We construct a finite planar
emulator for K_{1,2,2,2}. The existence of a finite planar cover for
K_{1,2,2,2} is still open.


title:
Is a rubidium cell with long decay time always useful for generating a
  non-classical photon pair?

abstract:
  We experimentally find an interesting and unexpected thing: a rubidium cell
with long decay time can not be used to generate a non-classical correlated
photon pair via the D2 transition of $^{87}$Rb using four-wave mixing
configuration [Opt. Express {\bf 16}, 21708 (2008)]. In this work, we give a
detail theoretical analysis on the EIT of hot $^{87}$Rb with different ground
decay time, which shows a probable reason why a rubidium cell with long decay
time is not a useful candidate for preparation of a non-classical photon pair
via the D2 transition. The simulations agree well with the experimental
results. We believe our find is very instructive to such kind of research.


title:
Algorithmic and Statistical Challenges in Modern Large-Scale Data
  Analysis are the Focus of MMDS 2008

abstract:
  The 2008 Workshop on Algorithms for Modern Massive Data Sets (MMDS 2008),
sponsored by the NSF, DARPA, LinkedIn, and Yahoo!, was held at Stanford
University, June 25--28. The goals of MMDS 2008 were (1) to explore novel
techniques for modeling and analyzing massive, high-dimensional, and
nonlinearly-structured scientific and internet data sets; and (2) to bring
together computer scientists, statisticians, mathematicians, and data analysis
practitioners to promote cross-fertilization of ideas.


title:
The discovery channel at the Neutrino Factory: $\nu_\mu\to\nu_\tau$
  pointing to sterile neutrinos

abstract:
  We study the potential of a Neutrino Factory in constraining the parameter
space of a scheme with one sterile neutrino separated from three active ones by
an O(1) eV^2, mass-squared difference. We present approximated analytic
expressions for the oscillation probabilities, showing that the greatest
sensitivity to sterile neutrinos at a Neutrino Factory can be achieved using
the \nu_\mu ->\nu_\mu and the \nu_\mu ->\nu_\tau oscillations. We have studied
two setups: a Neutrino Factory with 50 GeV (20 GeV) stored muons, with two
detectors of the Hybrid-MIND type (a magnetized ECC next to a magnetized iron
calorimeter), located at L=3000, 7500 km (L=4000, 7500 km) from the source.
Four channels have been used: \nu_e -> \nu_\mu,\nu_\tau; \nu_\mu ->
\nu_\mu,\nu_\tau. The relevant backgrounds, efficiencies and systematic errors
have been taken into account, and we have discussed dependence of the
sensitivities on the systematic errors. We have found that the 50 GeV (20 GeV)
setup can constrain \sin^2 2 \theta^{(4fam)}_{13} <= 7x10^{-5} (2x10^{-4});
\theta_{34} <= 12 deg (14 deg); and \theta_{24}<= 7.5 deg (8 deg). Our results
hold for any value of \Delta m^2_{Sbl} >~ 0.1 eV^2. Eventually we have shown
that, if a positive signal is found, the proposed setup is able to measure
simultaneously \theta_{34} and \delta_3 with a precision of few degrees and few
tens of degrees, respectively, solving the so-called "intrinsic" and "sign
degeneracies". Combination of \nu_\mu disappearance and of the \nu_\mu
->\nu_\tau channel, that will be called "the discovery channel", at the two
baselines is able to measure at 99% CL a new CP-violating phase \delta_3 for
\sin^2 2 \theta_{34} >= 0.06.


title:
Fermi surface nesting induced strong pairing in iron-based
  superconductors

abstract:
  The discovery of high-temperature superconductivity in iron pnictides raised
the possibility of an unconventional superconducting mechanism in multiband
materials. The observation of Fermi-surface(FS)-dependent nodeless
superconducting gaps suggested that inter-FS interactions may play a crucial
role in superconducting pairing. In the optimally hole-doped
Ba$_{0.6}$K$_{0.4}$Fe$_2$As$_2$, the pairing strength is enhanced
simultaneously (2$\Delta$/Tc$\sim$7) on the nearly nested FS pockets, i.e. the
inner holelike ($\alpha$) FS and the two hybridized electronlike FSs, while the
pairing remains weak (2$\Delta$/Tc$\sim$3.6) in the poorly-nested outer
hole-like ($\beta$) FS. Here we report that in the electron-doped
BaFe$_{1.85}$Co$_{0.15}$As$_2$ the FS nesting condition switches from the
$\alpha$ to the $\beta$ FS due to the opposite size changes for hole- and
electron-like FSs upon electron doping. The strong pairing strength
(2$\Delta$/Tc$\sim$6) is also found to switch to the nested $\beta$ FS,
indicating an intimate connection between FS nesting and superconducting
pairing, and strongly supporting the inter-FS pairing mechanism in the
iron-based superconductors.


title:
Bilateral counterparty risk valuation with stochastic dynamical models
  and application to Credit Default Swaps

abstract:
  We introduce the general arbitrage-free valuation framework for counterparty
risk adjustments in presence of bilateral default risk, including default of
the investor. We illustrate the symmetry in the valuation and show that the
adjustment involves a long position in a put option plus a short position in a
call option, both with zero strike and written on the residual net value of the
contract at the relevant default times. We allow for correlation between the
default times of the investor, counterparty and underlying portfolio risk
factors. We use arbitrage-free stochastic dynamical models. We then specialize
our analysis to Credit Default Swaps (CDS) as underlying portfolio,
generalizing the work of Brigo and Chourdakis (2008) [5] who deal with
unilateral and asymmetric counterparty risk. We introduce stochastic intensity
models and a trivariate copula function on the default times exponential
variables to model default dependence. Similarly to [5], we find that both
default correlation and credit spread volatilities have a relevant and
structured impact on the adjustment. Differently from [5], the two parties will
now agree on the credit valuation adjustment. We study a case involving British
Airways, Lehman Brothers and Royal Dutch Shell, illustrating the bilateral
adjustments in concrete crisis situations.


title: Soft disks in a narrow channel

abstract:
  The pressure components of "soft" disks in a two dimensional narrow channel
are analyzed in the dilute gas regime using the Mayer cluster expansion and
molecular dynamics. Channels with either periodic or reflecting boundaries are
considered. It is found that when the two-body potential, u(r), is singular at
some distance r_0, the dependence of the pressure components on the channel
width exhibits a singularity at one or more channel widths which are simply
related to r_0. In channels with periodic boundary conditions and for
potentials which are discontinuous at r_0, the transverse and longitudinal
pressure components exhibit a 1/2 and 3/2 singularity, respectively. Continuous
potentials with a power law singularity result in weaker singularities of the
pressure components. In channels with reflecting boundary conditions the
singularities are found to be weaker than those corresponding to periodic
boundaries.


title: Minimal Euclidean representations of graphs

abstract:
  A simple graph G is said to be representable in a real vector space of
dimension m if there is an embedding of the vertex set in the vector space such
that the Euclidean distance between any two distinct vertices is one of only
two distinct values a or b, with distance a if the vertices are adjacent and
distance b otherwise. The Euclidean representation number of G is the smallest
dimension in which G is representable. In this note, we bound the Euclidean
representation number of a graph using multiplicities of the eigenvalues of the
adjacency matrix. We also give an exact formula for the Euclidean
representation number using the main angles of the graph.


title: Universality in oscillation modes of superfluid neutron stars?

abstract:
  It has been well established that the $f$-mode of relativistic ordinary-fluid
neutron stars displays a universal scaling behavior. Here we study whether the
"ordinary" $f_{\rm o}$- and "superfluid" $f_{\rm s}$-modes of superfluid
neutron stars also show similar universal behavior. We first consider a simple
case where the neutron superfluid and normal fluid are decoupled, and with each
fluid modeled by a polytropic equation of state. We find that the $f_{\rm
o}$-mode obeys the same scaling laws as established for the $f$-mode of
orindary-fluid stars. However, the oscillation frequency of the $f_{\rm
s}$-mode obeys a different scaling law, which can be derived analytically from
a homogenous two-fluid stellar model in Newtonian gravity. Next the coupling
effect between the two fluids is studied via a parameterized model of
entrainment. We find that the coupling in general breaks the universal behavior
seen in the case of decoupled fluids. Based on a relativistic variational
principle, an approximated expression is derived for the first-order shift of
the $f_{\rm s}$-mode squared frequency due to the entrainment.


title:
Minimum Expected Distortion in Gaussian Source Coding with Fading Side
  Information

abstract:
  An encoder, subject to a rate constraint, wishes to describe a Gaussian
source under squared error distortion. The decoder, besides receiving the
encoder's description, also observes side information consisting of
uncompressed source symbol subject to slow fading and noise. The decoder knows
the fading realization but the encoder knows only its distribution. The
rate-distortion function that simultaneously satisfies the distortion
constraints for all fading states was derived by Heegard and Berger. A layered
encoding strategy is considered in which each codeword layer targets a given
fading state. When the side-information channel has two discrete fading states,
the expected distortion is minimized by optimally allocating the encoding rate
between the two codeword layers. For multiple fading states, the minimum
expected distortion is formulated as the solution of a convex optimization
problem with linearly many variables and constraints. Through a limiting
process on the primal and dual solutions, it is shown that single-layer rate
allocation is optimal when the fading probability density function is
continuous and quasiconcave (e.g., Rayleigh, Rician, Nakagami, and log-normal).
In particular, under Rayleigh fading, the optimal single codeword layer targets
the least favorable state as if the side information was absent.


title:
Curvature estimates for submanifolds with prescribed Gauss image and
  mean curvature

abstract:
  We study that the $n-$graphs defining by smooth map $f:\Om\subset \ir{n}\to
\ir{m}, m\ge 2,$ in $\ir{m+n}$ of the prescribed mean curvature and the Gauss
image. We derive the interior curvature estimates
$$\sup_{D_R(x)}|B|^2\le\f{C}{R^2}$$ under the dimension limitations and the
Gauss image restrictions. If there is no dimension limitation we obtain
$$\sup_{D_R(x)}|B|^2\le C
R^{-a}\sup_{D_{2R}(x)}(2-\De_f)^{-(\f{3}{2}+\f{1}{s})}, \qquad s=\min(m, n)$$
with $a<1$ under the condition
$$\De_f=[\text{det}(\de_{ij}+\sum_\a\pd{f^\a}{x^i}\pd{f^\a}{x^j})]^{\f{1}{2}}<2.$$
If the image under the Gauss map is contained in a geodesic ball of the radius
$\f{\sqrt{2}}{4}\pi$ in $\grs{n}{m}$ we also derive corresponding estimates.


title: Formation of Galactic Center Magnetic Loops

abstract:
  A survey for the molecular clouds in the Galaxy with NANTEN mm telescope has
discovered molecular loops in the Galactic center region. The loops show
monotonic gradients of the line of sight velocity along the loops and the large
velocity dispersions towards their foot points. It is suggested that these
loops are explained in terms of the buoyant rise of magnetic loops due to the
Parker instability. We have carried out global three-dimensional
magneto-hydrodynamic simulations of the gas disk in the Galactic center. The
gravitational potential is approximated by the axisymmetric potential proposed
by Miyamoto & Nagai (1975). At the initial state, we assume a warm (~ 10^4 K)
gas torus threaded by azimuthal magnetic fields. Self-gravity and radiative
cooling of the gas are ignored. We found that buoyantly rising magnetic loops
are formed above the differentially rotating, magnetically turbulent disk. By
analyzing the results of global MHD simulations, we have identified individual
loops, about 180 in the upper half of the disk, and studied their statistical
properties such as their length, width, height, and velocity distributions
along the loops. Typical length and height of a loop are 1kpc and 200pc,
respectively. The line of sight velocity changes linearly along a loop and
shows large dispersions around the foot-points. Numerical results indicate that
loops emerge preferentially from the region where magnetic pressure is large.
We argue that these properties are consistent with those of the molecular loops
discovered by NANTEN.


title:
Resonance--Continuum Interference in Light Higgs Boson Production at a
  Photon Collider

abstract:
  We study the effect of interference between the Standard Model Higgs boson
resonance and the continuum background in the process gamma gamma -> H -> b
b-bar at a photon collider. Taking into account virtual gluon exchange between
the final-state quarks, we calculate the leading corrections to the height of
the resonance for the case of a light (m_H < 160 GeV) Higgs boson. We find that
the interference is destructive and around 0.1--0.2% of the peak height,
depending on the mass of the Higgs and the scattering angle. This suppression
is smaller by an order of magnitude than the anticipated experimental accuracy
at a photon collider. However, the fractional suppression can be significantly
larger if the Higgs coupling to b quarks is increased by physics beyond the
Standard Model.


title:
Spin-bias driven magnetization reversal and nondestructive detection in
  a single molecular magnet

abstract:
  The magnetization reversal in a single molecular magnet (SMM) weakly coupled
to an electrode with spin-dependent splitting of chemical potentials (spin
bias) is theoretically investigated by means of the rate equation. A
microscopic mechanism for the reversal is demonstrated by the avalanche
dynamics at the reversal point. The magnetization as a function of the spin
bias shows hysteresis loops tunable by the gate voltage and varying with
temperature. The nondestructive measurement to the orientation of giant spin in
SMM is presented by measuring the fully polarized electric current in the
response to a small spin bias. For Mn$_{12}$ac molecule, its small transverse
anisotropy only slightly violates the results above. The situation when there
is an angle between the easy axis of the SMM and the spin quantization
direction of the electrode is also studied.


title: A Lieb-Thirring inequality for singular values

abstract:
  Let $A$ and $B$ be positive semidefinite matrices. We investigate the
conditions under which the Lieb-Thirring inequality can be extended to singular
values. That is, for which values of $p$ does the majorisation $\sigma(B^p A^p)
\prec_w \sigma((BA)^p)$ hold, and for which values its reversed inequality
$\sigma(B^p A^p) \succ_w \sigma((BA)^p)$.


title: Business processes integration and performance indicators in a PLM

abstract:
  In an economic environment more and more competitive, the effective
management of information and knowledge is a strategic issue for industrial
enterprises. In the global marketplace, companies must use reactive strategies
and reduce their products development cycle. In this context, the PLM (Product
Lifecycle Management) is considered as a key component of the information
system. The aim of this paper is to present an approach to integrate Business
Processes in a PLM system. This approach is implemented in automotive sector
with second-tier subcontractor


title:
Context-aware adaptation for group communication support applications
  with dynamic architecture

abstract:
  In this paper, we propose a refinement-based adaptation approach for the
architecture of distributed group communication support applications. Unlike
most of previous works, our approach reaches implementable, context-aware and
dynamically adaptable architectures. To model the context, we manage
simultaneously four parameters that influence Qos provided by the application.
These parameters are: the available bandwidth, the exchanged data communication
priority, the energy level and the available memory for processing. These
parameters make it possible to refine the choice between the various
architectural configurations when passing from a given abstraction level to the
lower level which implements it. Our approach allows the importance degree
associated with each parameter to be adapted dynamically. To implement
adaptation, we switch between the various configurations of the same level, and
we modify the state of the entities of a given configuration when necessary. We
adopt the direct and mediated Producer- Consumer architectural styles and
graphs for architecture modelling. In order to validate our approach we
elaborate a simulation model.


title:
Universal and reconfigurable logic gates in a noise-triggered artificial
  neuron node

abstract:
  Submicron-sized mesas of resonant tunneling diodes (RTDs) with split drain
contacts have been realized and the current-voltage characteristics have been
studied in the bistable regime at room temperature. Dynamically-biased, the
RTDs show noise-triggered firing of spike-like signals and can act as
reconfigurable universal logic gates for small voltage changes of a few mV at
the input branches. These observations are interpreted in terms of a stochastic
nonlinear processes in the split RTD, which are found to be robust against
noise. The split RTDs show also gain for the fired-signal bursts, can be easily
integrated to arrays of multiple inputs and have thus the potential to mimic
neuron nodes in nanoelectronic circuits.


title: Universal 1+2-body bound states in planar atomic wave guides

abstract:
  Shallow heteronuclear trimers are predicted for mixtures of two atomic
species strongly trapped in a quasi two-dimensional atomic wave guide. The
binding energies are functions of the 2D-scattering length and of the mass
ratio and can be thus tuned by various ways. These universal trimers are
composed of two identical non interacting particles and of a third particle of
the other species. Depending on the statistics of the two identical particles,
the trimers have an odd (fermions) or even (bosons) internal angular momentum.
These results permit to draw conclusions on the stability issue for the
quasi-2D gaseous phase of heteronuclear dimers.


title:
Architecture Logicielles pour des Applications h\'et\'erog\`enes,
  distribu\'ees et reconfigurables

abstract:
  The recent apparition of mobile wireless sensor aware to their physical
environment and able to process information must allow proposing applications
able to take into account their physical context and to react according to the
changes of the environment. It suppose to design applications integrating both
software and hardware components able to communicate. Applications must use
context information from components to measure the quality of the proposed
services in order to adapt them in real time. This work is interested in the
integration of sensors in distributed applications. It present a service
oriented software architecture allowing to manage and to reconfigure
applications in heterogeneous environment where entities of different nature
collaborate: software components and wireless sensors.


title:
Stability for Rayleigh-Benard convective solutions of the Boltzmann
  equation

abstract:
  We consider the Boltzmann equation for a gas in a horizontal slab, subject to
a gravitational force. The boundary conditions are of diffusive type,
specifying the wall temperatures, so that the top temperature is lower than the
bottom one (Benard setup). We consider a 2-dimensional convective stationary
solution, which is close for small Knudsen number to the convective stationary
solution of the Oberbeck-Boussinesq equations, near above the bifurcation
point, and prove its stability under 2-d small perturbations, for Rayleigh
number above and close to the bifurcation point and for small Knudsen number.


title: Loewner chains on the universal covering space of a Riemann surface

abstract:
  Let R be a hyperbolic Riemann surface with boundary $\partial R$ and suppose
that $\gamma:[0,T]\to R\cup\partial R$ is a simple curve growing from the
boundary of R. By lifting $R_{t}=R\setminus \gamma(0,t]$ to the universal
covering space of R (which we assume is the upper half-plane
$\mathbb{H}=\{z\in\mathbb{C}:Im[z]>0\}$) via the covering map
$\pi:\mathbb{H}\to R$, we can define a family of simply-connected domains
$D_{t}=\pi^{-1}(R_{t})$. For each $t\in[0,T]$, suppose that f_{t} is a
conformal map of \mathbb{H} onto D_{t} such that f(z,t)=f_{t}(z) is
differentiable almost everywhere in (0,T) with respect to t. In this paper, we
will derive a differential equation that describes how f(z,t) evolves in time
t. This should be viewed as an extension of the Loewner differential equation
to curves on Riemann surfaces with boundary.
  The motivation of this paper is the desire to extend Schramm's stochastic
Loewner evolution (SLE) to multiply-connected domains and Riemann surfaces.


title: The temperature influence on quantum tunneling in the spin-boson model

abstract:
  The existing studies of the temperature effect of the spin-boson model show
that the tunneling splitting will increase with temperature, no matter how weak
the couplings are between the bath and the spin. However, the small polaron
theory said that in the weak coupling and low temperature regime, the tunneling
is, in fact, dominated by the diagonal transitions whereas this diagonal
contribution to the tunneling should be faded away with increasing temperature.
Taking advantage of the analysis originated from the Feynman-Vernon's influence
functional theory, the influence on the tunneling by the phonon bath can be
expressed as a product of the effects of every single phonon mode, which can be
studied by numerical exact diagonalization. We find that, in the weak coupling
and low temperature regime, all the spin-single-mode systems exhibit the same
decreasing dependence of tunneling on increasing temperature. In turn, with the
conclusion of influence functional theory, the tunneling of the spin-boson
model should decrease and it is independent of the bath structure. In the
strong coupling regime, however, the temperature effect reverses from
suppressing to enhancing the tunneling with the increase of temperature.
Discrepancies between the old theories and the small polaron theory are also
explained.


title: The nature of red dwarf galaxies

abstract:
  Using dark matter halos traced by galaxy groups selected from the Sloan
Digital Sky Survey Data Release 4, we find that about 1/4 of the faint galaxies
($\rmag >-17.05$, hereafter dwarfs) that are the central galaxies in their own
halo are not blue and star forming, as expected in standard models of galaxy
formation, but are red. In contrast, this fraction is about 1/2 for dwarf
satellite galaxies. Many red dwarf galaxies are physically associated with more
massive halos. In total, about $\sim 45$% of red dwarf galaxies reside in
massive halos as satellites, while another $\sim 25$% have a spatial
distribution that is much more concentrated towards their nearest massive
haloes than other dwarf galaxies. We use mock catalogs to show that the reddest
population of non-satellite dwarf galaxies are distributed within about 3 times
the virial radii of their nearest massive halos. We suggest that this
population of dwarf galaxies are hosted by low-mass halos that have passed
through their massive neighbors, and that the same environmental effects that
cause satellite galaxies to become red are also responsible for the red colors
of this population of galaxies. We do not find any significant radial
dependence of the population of dwarf galaxies with the highest concentrations,
suggesting that the mechanisms operating on these galaxies affect color more
than structure. However, over 30% of dwarf galaxies are red and isolated and
their origin remains unknown.


title: Markov triplets on CCR-algebras

abstract:
  The paper contains a detailed computation about the algebra of canonical
commutation relation, the representation of the Weyl unitaries, the quasi-free
states and their von Neumann entropy. The Markov triplet is defined by constant
entropy increase. The Markov property of a quasi-free state is described by the
representing block matrix. The proof is based on results on the statistical
sufficiency in the quantum case. The relation to classical Gaussian Markov
triplets is also described.


title: Three Views of a Secret in Relativistic Thermodynamics

abstract:
  It has been shown three different views in relativistic thermodynamics can be
derived from the basic formulation proposed by van Kampen and Israel. The way
to decompose energy-momentum into the reversible and irreversible parts is not
uniquely determined, and different choices result in different views. The
effect of difference in the definition of a finite volume is also considered.


title: Motivations for Imaging Spectroscopy at Dome C

abstract:
  Antarctica offers unique conditions for ground-based observations, such as
low sky background in the infrared, improved seeing, and low turbulence and
scintillation noise. These properties are particularly beneficial to imaging,
precision photometry, and infrared observations. It may be less clear if
Antarctica offers equally compelling advantages for spectroscopy, in particular
in the optical domain. However, scientific programmes that make use of imaging
(or 3D) spectroscopy for selected follow-up studies of IR surveys, long-term
monitoring of extended targets and resolved stellar population studies in
crowded fields, also benefit from the site conditions at Dome C.


title:
Optimal spin-quantization axes for quarkonium with large transverse
  momentum

abstract:
  The gluon collision process that creates a heavy-quark-antiquark pair with
small relative momentum and large transverse momentum predicts at leading-order
in the QCD coupling constant that the transverse polarization of the pair
should increase with its transverse momentum. Measurements at the Fermilab
Tevatron of the polarization of charmonium and bottomonium states with respect
to a particular spin-quantization axis are inconsistent with this prediction.
However the predicted rate of approach to complete transverse polarization
depends on the choice of spin-quantization axis. We introduce axes that
maximize and minimize the transverse polarization from the leading-order gluon
collision process. They are determined by the direction of the jet that
provides most of the balancing transverse momentum.


title:
The metal insulator transition in cluster dynamical mean field theory:
  intersite correlation, cluster size, interaction strength, and the location
  of the transition line

abstract:
  To gain insight into the physics of the metal insulator transition and the
effectiveness of cluster dynamical mean field theory (DMFT) we have used one,
two and four site dynamical mean field theory to solve a polaron model of
electrons coupled to a classical phonon field. The cluster size dependence of
the metal to polaronic insulator phase boundary is determined along with
electron spectral functions and cluster correlation functions. Pronounced
cluster size effects start to occur in the intermediate coupling region in
which the cluster calculation leads to a gap and the single-site approximation
does not. Differences (in particular a sharper band edge) persist in the strong
coupling regime. A partial density of states is defined encoding a generalized
nesting property of the band structure; variations in this density of states
account for differences between the dynamical cluster approximation and the
cellular-DMFT implementations of cluster DMFT, and for differences in behavior
between the single band models appropriate for cuprates and the multiband
models appropriate for manganites. A pole or strong resonance in the self
energy is associated with insulating states; the momentum dependence of the
pole is found to distinguish between Slater-like and Mott-like mechanisms for
metal insulator transition. Implications for the theoretical treatment of doped
manganites are discussed.


title: C/O white dwarfs of very low mass: 0.33-0.5 Mo

abstract:
  The standard lower limit for the mass of white dwarfs (WDs) with a C/O core
is roughly 0.5 Mo. In the present work we investigated the possibility to form
C/O WDs with mass as low as 0.33 Mo. Both the pre-WD and the cooling evolution
of such nonstandard models will be described.


title:
Optimal three-ball inequalities and quantitative uniqueness for the
  Stokes system

abstract:
  In this paper we study the local behavior of a solution to the Stokes system
with singular coefficients. One of the main results is the bound on the
vanishing order of a nontrivial solution to the Stokes system, which is a
quantitative version of the strong unique continuation property. Our proof
relies on some delicate Carleman-type estimates. We first use these estimates
to derive crucial \emph{optimal} three-ball inequalities. Taking advantage of
the optimality, we then derive an upper bound on the vanishing order of any
nontrivial solution to the Stokes system from those three-ball inequalities.


title:
Dimensional crossover in Sr$_2$RuO$_4$ within slave-boson mean-field
  theory

abstract:
  Motivated by the anomalous temperature dependence of the c-axis resistivity
of Sr$_2$RuO$_4$, the dimensional crossover from a network of perpendicular
one-dimensional chains to a two-dimensional system due to a weak hybridization
between the perpendicular chains is studied. The corresponding two-orbital
Hubbard model is treated within a slave-boson mean-field theory (SBMFT) to take
correlation effects into account such as the spin-charge separation on the
one-dimensional chains. Using an RPA-like formulation for the Green's function
of collective spinon-holon excitations the emergence of quasiparticles at
low-temperatures is examined. The results are used to discuss the evolution of
the spectral density and the c-axis transport within a tunneling approach. For
the latter a regime change between low- and high-temperature regime is found in
qualitative accordance with experimental data.


title:
Bandwidth tuning triggers interplay of charge order and
  superconductivity in two-dimensional organic materials

abstract:
  We observe charge-order fluctuations in the quasi-two-dimensional organic
superconductor $\beta^{\prime\prime}$-(BEDT-TTF)2 SF5 CH2 CF2 SO3 both by means
of vibrational spectroscopy, locally probing the fluctuating charge order, and
investigating the in-plane dynamical response by infrared reflectance
spectroscopy. The decrease of effective electronic interaction in an
isostructural metal suppresses both charge-order fluctuations and
superconductivity, pointing on their interplay. We compare the results of our
experiments with calculations on the extended Hubbard model.


title:
A census of molecular hydrogen outflows and their sources along the
  Orion A molecular ridge: characteristics and overall distribution

abstract:
  We present wide-field near-IR images of Orion A. K and H2 1-0S(1) images of a
contiguous 8 sqr degree region are compared to photometry from Spitzer and
dust-continuum maps obtained with MAMBO and SCUBA. We also measure proper
motions for H2 features in 33 outflows. We increase the number of known H2
outflows in Orion A to 116. A total of 111 H2 flows were observed with Spitzer;
outflow sources are identified for at least 72 of them. The MAMBO 1200 micron
maps cover 97 H2 flows; 57 of them are associated with Spitzer sources and dust
cores or extended emission. The H2 jets are widely distributed and randomly
orientated; the jets do not appear to be orthogonal to large-scale filaments or
even to the small-scale cores. Moreover, H2 jet lengths and opening angles are
not obviously correlated with indicators of outflow source age - source
spectral index or (sub)millimetre core flux. We demonstrate that H2 jet sources
are predominantly protostellar with flat or positive spectral indices, rather
than disk-excess (or T Tauri) stars. Most protostars in molecular cores drive
H2 outflows. However, not all molecular cores are associated with protostars or
H2 jets. On statistical grounds, the H2 jet phase may be marginally shorter
than the protostellar phase, though must be considerably shorter than the
prestellar phase. In terms of their spectral index, H2 jet sources are
indistinguishable from protostars. The few true protostars without H2 jets are
almost certainly more evolved than their H2-jet-driving counterparts. We also
find that protostars that power molecular outflows are no more (nor no less)
clustered than protostars that do not. The H2 emission regions in outflows from
young stars clearly weaken and fade very quickly, before the source evolves
from protostar to pre-main-sequence star.


title: Common fixed point theorems for occasionally weakly compatible maps

abstract:
  In this paper, we establish a common fixed point theorem for two pairs of
occasionally weakly compatible single and set-valued maps satisfying a strict
contractive condition in a metric space. Our result extends many results
existing in the literature as those of Aliouche and Popa [15-20]. Also we
establish another common fixed point theorem for four owc single and set-valued
maps of Gregu% \v{s} type which generalizes the results of Djoudi and Nisse,
Pathak, Cho, Kang and Madharia and we end our work by giving a third theorem
which extends the results given by Elamrani & Mehdaoui and Mbarki.


title:
Semi-leptonic Octet Baryon Weak Axial-Vector Form Factors in the Chiral
  Constitutent Quark Model

abstract:
  The weak vector and axial-vector form factors have been investigated for the
semi-leptonic octet baryon decays in the chiral constituent quark model with
configuration mixing (\chiCQM_{config}). The effects of SU(3) symmetry breaking
and configuration mixing have also been investigated and the results are not
only in good agreement with existing experimental data but also show
improvement over other phenomenological models.


title: Two destructive effects of decoherence on Bell inequality violation

abstract:
  We consider a system of two spin-1/2 particles, initially in an entangled
Bell state. If one of the particles is interacting with an environment (e.g. a
collection of N independent spins), the two-particle system undergoes
decoherence. Using a simple model of decoherence, we show that this process has
two consequences. First, the maximal amount by which the CHSH inequality is
violated decays to zero. Second, the set of directions of measurement for which
the inequality is violated is reduced in the course of decoherence. The volume
of that set is bounded above by C|r|^2, where r is the decoherence factor. We
obtain similar results for the case when each of the two particles is in
interaction with a separate environment.


title:
Time-evolution of Peak Energy and Luminosity Relation within Pulses for
  GRB 061007: Probing Fireball Dynamics

abstract:
  We perform a time-resolved spectral analysis of bright, long Gamma-ray burst
GRB 061007 using Suzaku/WAM and Swift/BAT. Thanks to the large effective area
of the WAM, we can investigate the time evolution of the spectral peak energy,
Et_peak and the luminosity Lt_iso with 1-sec time resolution, and we find that
luminosity Lt_iso with 1-sec time resolution, and we find that the
time-resolved pulses also satisfy the Epeak-Liso relation, which was found for
the time-averaged spectra of other bursts, suggesting the same physical
conditions in each pulse. Furthermore, the initial rising phase of each pulse
could be an outlier of this relation with higher Et_peak value by about factor
2. This difference could suggest that the fireball radius expands by a factor
of 2-4 and/or bulk Lorentz factor of the fireball is decelerated by a factor of
4 during the initial phase, providing a new probe of the fireball dynamics in
real time.


title:
Unified Statistical Description of Quasithermodynamic Systems in and out
  of Equilibrium

abstract:
  We propose the method of statistical description of broad class of dynamic
systems (DS) whose equations of motion are determined by two state depending
functions: 1) "energy" - the quantity which conserves in time and 2) "entropy"
- the quantity which does not decrease in time. It is demonstrated that the
behavior of such systems in the equilibrium state reduces to the thermodynamic
lows in particular the Le Chatelier principle is satisfed and so on. Taking
into account the interaction system of interest with ergometer - the device
which continuously measures its energy one can possible to find the system
distribution function in arbitrary non-equilibrium stationary state (NESS).
Some general relations for mean values of certain quantities in NESS which can
be compared with experimental data are obtained.


title: The Milky Way's external disc constrained by 2MASS star counts

abstract:
  Context. Thanks to recent large scale surveys in the near infrared such as
2MASS, the galactic plane that most suffers from extinction is revealed and its
overall structure can be studied. Aims. This work aims at constraining the
structure of the Milky Way external disc as seen in 2MASS data, and in
particular the warp. Methods. We use the Two Micron All Sky Survey (hereafter
2MASS) along with the Stellar Population Synthesis Model of the Galaxy,
developed in Besancon, to constrain the external disc parameters such as its
scale length, its cutoff radius, and the slope of the warp. In order to
properly interpret the observations, the simulated stars are reddened using a
three dimensional extinction map. The shape of the stellar warp is then
compared with previous results and with similar structures in gas and dust.
Results. We find new constraints on the stellar disc, which is shown to be
asymmetrical, similar to observations of HI. The positive longitude side is
found to be easily modelled with a S shape warp but with a slope significantly
smaller than the slope seen in the HI warp. At negative longitudes, the disc
presents peculiarities which are not well reproduced by any simple model.
Finally, comparing with the warp seen in the dust, it seems to follow a slope
intermediate between the gas and the stars.


title: The Merger of the Schwarzschild metric and the Robertson-Walker metric

abstract:
  The Schwarzschild metric giving the space time due to a spherically symmetric
object is derived in the background of the Robertson Walker metric. In other
words the two metrics are merged. It is found that under certain conditions the
merger is at a distance less than the radius of the spherically symmetric
object, thus not separating the object from the rest of the universe.


title:
The ultracool eld dwarfs luminosity function from the Canada-France
  Brown Dwarf Survey

abstract:
  The Canada-France Brown Dwarf Survey is a wide eld survey for cool brown
dwarfs conducted with the MegaCam camera on the CFHT telescope. Our objectives
are to nd ultracool brown dwarfs and to constrain the eld brown dwarf mass
function from a large and homogeneous sample of L and T dwarfs. We identify
candidates in CFHT/Megacam i' and z' images and follow them up with pointed NIR
imaging on several telescopes. Our survey has to date found 50 T dwarfs
candidates and 170 L or late M dwarf candidates drawn from a larger sample of
1300 candidates with typical ultracool dwarfs i'-z' colours, found in 900
square degrees. We currently have completed the NIR follow-up on a large part
of the survey for all candidates from the latest T dwarfs known to the late L
color range. This allows us to build on a complete and well de ned sample of
ultracool dwarfs to investigate the luminosity function of eld L and T dwarfs.


title: Quickest Change Detection of a Markov Process Across a Sensor Array

abstract:
  Recent attention in quickest change detection in the multi-sensor setting has
been on the case where the densities of the observations change at the same
instant at all the sensors due to the disruption. In this work, a more general
scenario is considered where the change propagates across the sensors, and its
propagation can be modeled as a Markov process. A centralized, Bayesian version
of this problem, with a fusion center that has perfect information about the
observations and a priori knowledge of the statistics of the change process, is
considered. The problem of minimizing the average detection delay subject to
false alarm constraints is formulated as a partially observable Markov decision
process (POMDP). Insights into the structure of the optimal stopping rule are
presented. In the limiting case of rare disruptions, we show that the structure
of the optimal test reduces to thresholding the a posteriori probability of the
hypothesis that no change has happened. We establish the asymptotic optimality
(in the vanishing false alarm probability regime) of this threshold test under
a certain condition on the Kullback-Leibler (K-L) divergence between the post-
and the pre-change densities. In the special case of near-instantaneous change
propagation across the sensors, this condition reduces to the mild condition
that the K-L divergence be positive. Numerical studies show that this low
complexity threshold test results in a substantial improvement in performance
over naive tests such as a single-sensor test or a test that wrongly assumes
that the change propagates instantaneously.


title: The Galactic bulge as seen in optical surveys

abstract:
  The bulge is a region of the Galaxy of tremendous interest for understanding
galaxy formation. However measuring photometry and kinematics in it raises
several inherent issues, such as severe crowding and high extinction in the
visible. Using the Besancon Galaxy model and a 3D extinction map, we estimate
the stellar density as a function of longitude, latitude and apparent magnitude
and we deduce the possibility of reaching and measuring bulge stars with Gaia.
We also present an ongoing analysis of the bulge using the Canada-France-Hawaii
Telescope.


title: Signature change events: A challenge for quantum gravity?

abstract:
  Within the framework of either Euclidian (functional-integral) quantum
gravity or canonical general relativity the signature of the manifold is a
priori unconstrained. Furthermore, recent developments in the emergent
spacetime programme have led to a physically feasible implementation of
signature change events. This suggests that it is time to revisit the sometimes
controversial topic of signature change in general relativity. Specifically, we
shall focus on the behaviour of a quantum field subjected to a manifold
containing regions of different signature. We emphasise that, regardless of the
underlying classical theory, there are severe problems associated with any
quantum field theory residing on a signature-changing background. (Such as the
production of what is naively an infinite number of particles, with an infinite
energy density.) From the viewpoint of quantum gravity phenomenology, we
discuss possible consequences of an effective Lorentz symmetry breaking scale.
To more fully understand the physics of quantum fields exposed to finite
regions of Euclidean-signature (Riemannian) geometry, we show its similarities
with the quantum barrier penetration problem, and the super-Hubble horizon
modes encountered in cosmology. Finally we raise the question as to whether
signature change transitions could be fully understood and dynamically
generated within (modified) classical general relativity, or whether they
require the knowledge of a full theory of quantum gravity.


title: Maxwell-Kosteleck\'y Electromagnetism and Cosmic Magnetization

abstract:
  The Lorentz violating term in the photon sector of Standard Model Extension,
$\mathcal{L}_K = -{$\frac14$} (k_F)_{\alpha \beta \mu \nu} F^{\alpha \beta}
F^{\mu \nu}$ (here referred to as the Kosteleck\'{y} term), breaks conformal
invariance of electromagnetism and enables a superadiabatic amplification of
magnetic vacuum fluctuations during inflation. For a wide range of values of
parameters defining Lorentz symmetry violation and inflation, the present-day
magnetic field can have an intensity of order of nanogauss on megaparsec scales
and then could explain the large-scale magnetization of the universe.


title:
The Imprimitive Faithful Complex Characters of the Schur Covers of the
  Symmetric and Alternating Groups

abstract:
  Using combinatorics and character theory, we determine the imprimitive
faithful complex characters, i.e., the irreducible faithful complex characters
which are induced from proper subgroups, of the Schur covers of the symmetric
and alternating groups. Furthermore, for every imprimitive character we
establish all its minimal block stabilizers. As a corollary, we also determine
the monomial faithful characters of the Schur covers.


title:
Upper bounds on $f_D$ and $f_{D_s}$ from two-point correlation function
  in QCD

abstract:
  The correlation function of two pseudoscalar charmed quark currents with a
positive hadronic spectral density is employed to obtain upper bounds on the
decay constants of $D$ and $D_s$ mesons. Including all known terms of the
operator-product-expansion of this correlation function in QCD and taking into
account the estimated uncertainties, we obtain $f_{D}<230 $ MeV and
$f_{D_s}<270$ MeV. Comparison with the decay constants determined from $D\to l
\nu_l$ and $D_s\to l \nu_l$ measurements, reveals a tension between the bound
and current experimental value of $f_{D_s}$.


title:
An Explicit Scheme for Incorporating Ambipolar Diffusion in a
  Magnetohydrodynamics Code

abstract:
  We describe a method for incorporating ambipolar diffusion in the strong
coupling approximation into a multidimensional magnetohydrodynamics code based
on the total variation diminishing scheme. Contributions from ambipolar
diffusion terms are included by explicit finite difference operators in a fully
unsplit way, maintaining second order accuracy. The divergence-free condition
of magnetic fields is exactly ensured at all times by a flux-interpolated
constrained transport scheme. The super time stepping method is used to
accelerate the timestep in high resolution calculations and/or in strong
ambipolar diffusion. We perform two test problems, the steady-state oblique
C-type shocks and the decay of Alfv\'en waves, confirming the accuracy and
robustness of our numerical approach. Results from the simulations of the
compressible MHD turbulence with ambipolar diffusion show the flexibility of
our method as well as its ability to follow complex MHD flows in the presence
of ambipolar diffusion. These simulations show that the dissipation rate of MHD
turbulence is strongly affected by the strength of ambipolar diffusion.


title:
A multiwavelength investigation of the massive eclipsing binary Cyg OB2
  #5

abstract:
  The properties of the early-type binary Cyg OB2 #5 have been debated for many
years and spectroscopic and photometric investigations yielded conflicting
results. We have attempted to constrain the physical properties of the binary
by collecting new optical and X-ray observations. We find that the orbital
period of the system slowly changes though we are unable to discriminate
between several possible explanations of this trend. The best fit solution of
the continuum light curve reveals a contact configuration with the secondary
star being significantly brighter and hotter on its leading side facing the
primary. The mean temperature of the secondary star turns out to be only
slightly lower than that of the primary, whilst the bolometric luminosity ratio
is found to be 3.1. The solution of the light curve yields a distance of 925
+/- 25 pc much lower than the usually assumed distance of the Cyg OB2
association. Whilst we confirm the existence of episodes of higher X-ray
fluxes, the data reveal no phase-locked modulation with the 6.6 day period of
the eclipsing binary nor any clear relation between the X-ray flux and the 6.7
yr radio cycle. The bright region of the secondary star is probably heated by
energy transfer in a common envelope in this contact binary system as well as
by the collision with the primary's wind. The existence of a common photosphere
probably also explains the odd mass-luminosity relation of the stars in this
system. Most of the X-ray, non-thermal radio, and possibly gamma-ray emission
of Cyg OB2 #5 is likely to arise from the interaction of the combined wind of
the eclipsing binary with at least one additional star of this multiple system.


title: The reaction e+e- --> hh recomputed

abstract:
  We notice that the existing literature about the reaction e+e- --> hh suffers
from a mistake in the relative sign between the t-channel and u-channel graphs.
Correcting this lowers the crosssections by about an order of magnitude.


title: Gold in graphene: in-plane adsorption and diffusion

abstract:
  We study the bonding and diffusion of Au in graphene vacancies using
density-functional theory. Energetics show that Au adsorbs preferably to double
vacancies, steadily in-plane with graphene. All diffusion barriers for the
complex of Au in double vacancy are above 4 eV, whereas the barriers for larger
vacancies are below 2 eV. Our results support the main results of a recent
experiment [Gan et al., Small 4, 587 (2008)], but suggest that the observed
diffusion mechanism is not thermally activated, but radiation-enhanced.