title:
Identifying 'Hidden' Communities of Practice within Electronic Networks:
  Some Preliminary Premises

abstract:
  This paper examines the possibility of discovering 'hidden' (potential)
Communities of Practice (CoPs) inside electronic networks, and then using this
knowledge to nurture them into a fully developed Virtual Community of Practice
(VCoP). Starting from the standpoint of the need to manage knowledge, it
discusses several questions related to this subject: the characteristics of
'hidden' communities; the relation between CoPs, Virtual Communities (VCs),
Distributed Communities of Practice (DCoPs) and Virtual Communities of Practice
(VCoPs); the methods used to search for 'hidden' CoPs; and the possible ways of
changing 'hidden' CoPs into fully developed VCoPs. The paper also presents some
preliminary findings from a semi-structured interview conducted in The Higher
Education Academy Psychology Network (UK). These findings are contrasted
against the theory discussed and some additional proposals are suggested at the
end.


title:
Philosophical Smoke Signals: Theory and Practice in Information Systems
  Design

abstract:
  Although the gulf between the theory and practice in Information Systems is
much lamented, few researchers have offered a way forward except through a
number of (failed) attempts to develop a single systematic theory for
Information Systems. In this paper, we encourage researchers to re-examine the
practical consequences of their theoretical arguments. By examining these
arguments we may be able to form a number of more rigorous theories of
Information Systems, allowing us to draw theory and practice together without
undertaking yet another attempt at the holy grail of a single unified
systematic theory of Information Systems.


title:
Radio source calibration for the VSA and other CMB instruments at around
  30 GHz

abstract:
  Accurate calibration of data is essential for the current generation of CMB
experiments. Using data from the Very Small Array (VSA), we describe procedures
which will lead to an accuracy of 1 percent or better for experiments such as
the VSA and CBI. Particular attention is paid to the stability of the receiver
systems, the quality of the site and frequent observations of reference
sources. At 30 GHz the careful correction for atmospheric emission and
absorption is shown to be essential for achieving 1 percent precision. The
sources for which a 1 percent relative flux density calibration was achieved
included Cas A, Cyg A, Tau A and NGC7027 and the planets Venus, Jupiter and
Saturn. A flux density, or brightness temperature in the case of the planets,
was derived at 33 GHz relative to Jupiter which was adopted as the fundamental
calibrator. A spectral index at ~30 GHz is given for each. Cas A,Tau A, NGC7027
and Venus were examined for variability. Cas A was found to be decreasing at
$0.394 \pm 0.019$ percent per year over the period March 2001 to August 2004.
In the same period Tau A was decreasing at $0.22\pm 0.07$ percent per year. A
survey of the published data showed that the planetary nebula NGC7027 decreased
at $0.16\pm 0.04$ percent per year over the period 1967 to 2003. Venus showed
an insignificant ($1.5 \pm 1.3$ percent) variation with Venusian illumination.
The integrated polarization of Tau A at 33 GHz was found to be $7.8\pm 0.6$
percent at pa $ = 148^\circ \pm 3^\circ$.}


title: Gauge/gravity duality with a chiral N=(0,8) string defect

abstract:
  We study the defect AdS/CFT correspondence for a system of N_c D3-branes
intersecting certain configurations of D7-branes and O7-planes in
1+1-dimensions. The intersection is chiral, preserving N=(0,8) supersymmetry.
The geometry produced by the 7-branes does not decouple in the low energy limit
on the D3-branes; consequently the field theory must be considered in the
curved background of the 7-branes, and the supergravity background is the fully
backreacted solution accounting for both sets of branes. Although we can not
work in the probe-brane limit, we still find a consistent defect mode-operator
map. In our previous study of the field theory we found chiral D3-brane
zero-modes that localized to the intersection. Here we obtain a dual
supergravity description of the localized R-symmetry anomaly that these
zero-modes produce.


title: Modulated X-ray Emissivity near the Stress Edge in Sgr A*

abstract:
  Sgr A* is thought to be the radiative manifestation of a ~3.6E6 Msun
supermassive black hole at the Galactic center. Its mm/sub-mm spectrum and its
flare emission at IR and X-ray wavelengths may be produced within the inner ten
Schwarzschild radii of a hot, magnetized Keplerian flow. The lightcurve
produced in this region may exhibit quasi-periodic variability. We present
ray-tracing simulations to determine the general-relativistically modulated
X-ray luminosity expected from plasma coupled magnetically to the rest of the
disk as it spirals inwards below the innermost stable circular orbit towards
the "stress edge" in the case of a Schwarzschild metric. The resulting
lightcurve exhibits a modulation similar to that observed during a recent X-ray
flare from Sgr A*.


title:
Three-fluid plasmas in star formation II. Momentum transfer rate
  coefficients

abstract:
  The charged component of the insterstellar medium consists of atomic and
molecular ions, electrons, and charged dust grains, coupled to the local
Galactic magnetic field. Collisions between neutral particles (mostly atomic or
molecular hydrogen) and charged species, and between the charged species
themselves, affect the magnetohydrodynamical behaviour of the medium and the
dissipation of electric currents. The friction force due to elastic collisions
between particles of different species in the multi-component interstellar
plasma is a nonlinear function of the temperature of each species and the Mach
number of the relative drift velocity. The aim of this paper is to provide an
accurate and, as far as possible, complete set of momentum transfer rate
coefficients for magnetohydrodynamical studies of the interstellar medium.
Momentum transfer rates are derived from available experimental data and
theoretical calculations of cross sections within the classic approach
developed by Boltzmann and Langevin for a wide range of values of the
temperature and the drift velocity. Accurate numerical values for momentum
transfer rates are obtained and fitted to simple analytical formulae expressing
the dependence of the results on the gas temperature and the relative drift
velocity. The often used polarization approximation is in satisfactory
agreement with our results only for collisions between H2and molecular ions
(HCO+, H3+). For other kinds of collisions, the polarization approximation
fails by large factors, and must be replaced by more accurate expressions.


title: Geometric massive higher spins and current exchanges

abstract:
  Generalised Fierz-Pauli mass terms allow to describe massive higher-spin
fields on flat background by means of simple quadratic deformations of the
corresponding geometric, massless Lagrangians. In this framework there is no
need for auxiliary fields. We briefly review the construction in the bosonic
case and study the interaction of these massive fields with external sources,
computing the corresponding propagators. In the same fashion as for the massive
graviton, but differently from theories where auxiliary fields are present, the
structure of the current exchange is completely determined by the form of the
mass term itself.


title: On the Brane Cosmology of KK Gravitinos

abstract:
  In this report I consider the cosmology of KK gravitinos in models with extra
dimensions, in particular in connection with the known non--standard high
energy regime of expansion which is associated with them. The main result is
that the production of such KK modes, once one considers BBN constraints on the
allowed entropy released in their decays, is not compatible with non--standard
expansion after inflation: there is no five--dimensional Planck mass for which
the produced KK gravitinos are safe with respect to BBN. This conclusion holds
for both flat and warped models in which only gravity propagates in the full
spacetime. This report is based on the work arXiv:0705.4227 [hep-ph].


title:
Movable algebraic singularities of second-order ordinary differential
  equations

abstract:
  Any nonlinear equation of the form y''=\sum_{n=0}^N a_n(z)y^n has a
(generally branched) solution with leading order behaviour proportional to
(z-z_0)^{-2/(N-1)} about a point z_0, where the coefficients a_n are analytic
at z_0 and a_N(z_0)\ne 0. We consider the subclass of equations for which each
possible leading order term of this form corresponds to a one-parameter family
of solutions represented near z_0 by a Laurent series in fractional powers of
z-z_0. For this class of equations we show that the only movable singularities
that can be reached by analytic continuation along finite-length curves are of
the algebraic type just described. This work generalizes previous results of S.
Shimomura. The only other possible kind of movable singularity that might occur
is an accumulation point of algebraic singularities that can be reached by
analytic continuation along infinitely long paths ending at a finite point in
the complex plane. This behaviour cannot occur for constant coefficient
equations in the class considered. However, an example of R. A. Smith shows
that such singularities do occur in solutions of a simple autonomous
second-order differential equation outside the class we consider here.


title:
The sign of Galois representations attached to automorphic forms for
  unitary groups

abstract:
  We determine the sign of the polarization of any polarized irreducible factor
of a Galois representation attached to a polarized cohomological cuspidal
automorphic form of Gl_n of a CM field: it is always +1, as was conjectured by
Gross.


title: Observation of surface solitons in chirped waveguide arrays

abstract:
  We report the observation of surface solitons in chirped semi-infinite
waveguide arrays whose waveguides exhibit exponentially decreasing refractive
indices. We show that the power threshold for surface wave formation decreases
with an increase of the array chirp and that for sufficiently large chirp
values linear surface modes are supported.


title: On the Mass to Charge Ratio of Neutron Cores and Heavy Nuclei

abstract:
  We determine theoretically the relation between the total number of protons
$N_{p}$ and the mass number $A$ (the charge to mass ratio) of nuclei and
neutron cores with the model recently proposed by Ruffini et al. (2007) and we
compare it with other $N_p$ versus $A$ relations: the empirical one, related to
the Periodic Table, and the semi-empirical relation, obtained by minimizing the
Weizs\"{a}cker mass formula. We find that there is a very good agreement
between all the relations for values of $A$ typical of nuclei, with differences
of the order of per cent. Our relation and the semi-empirical one are in
agreement up to $A\sim 10^4$; for higher values, we find that the two relations
differ. We interprete the different behaviour of our theoretical relation as a
result of the penetration of electrons (initially confined in an external
shell) inside the core, that becomes more and more important by increasing $A$;
these effects are not taken into account in the semi-empirical mass-formula.


title: Origin of the geometric tachyon

abstract:
  The motion of a Dp-brane in the background of a stack of coincident
NS5-branes is analysed as the motion of a relativistic point particle in the
transverse space of the five-branes. In this system, the particle experiences a
proper acceleration orthogonal to its proper velocity due to the background
dilaton field which changes the dynamics from that of a simple geodesic motion.
In particular, we show that in the vicinity of the five-branes, it is this
acceleration which is responsible for modifying the motion of the radial mode
to that of an inverted simple harmonic oscillator leading to the tachyonic
instability.


title: The Youthful Appearance of the 2003 EL61 Collisional Family

abstract:
  We present new solar phase curve observations of the 2003 EL61 collisional
family showing that all the members have light-scattering properties similar to
the bright icy satellites and dwarf planets. Compared to other Kuiper Belt
objects, the five family members we observe (2003 EL61, 2002 TX300, 2003 OP32,
2005 RR43, and 1995 SM55) have conspicuously neutral color (V-I = 0.6-0.8 mag)
and flat phase curves at small phase angles (phase coefficients of 0.0 - 0.1
mag deg-1). Comparing the phase curves we observe for other icy Kuiper Belt
objects to the phase curves of icy satellites, we find that the flat phase
curves of the 2003 EL61 family are an indication they have high albedo surfaces
coated with fresh ice in the last ~100 Myr. We examine possible resurfacing
processes and find none that are plausible. To avoid the influence of cosmic
radiation that darkens and reddens most icy surfaces on times scales > ~100
Myr, the family members must be unusually depleted in carbon, or else the
collision that created the family occurred so recently that the parent body and
fragments have not had time to darken. We also find a rotation period of 4.845
(+/- 0.003) h with amplitude 0.26 (+/- 0.04) mags for 2003 OP32.


title:
Fermion mass hierarchy and non-hierarchical mass ratios in SU(5) x
  U(1)_F

abstract:
  We consider a SU(5) x U(1)_F GUT-flavor model in which the number of effects
that determine the charged fermions Yukawa matrices is much larger than the
number of observables, resulting in a hierarchical fermion spectrum with no
particular regularities. The GUT-flavor symmetry is broken by flavons in the
adjoint of SU(5), realizing a variant of the Froggatt-Nielsen mechanism that
gives rise to a large number of effective operators. By assuming a common mass
for the heavy fields and universality of the fundamental Yukawa couplings, we
reduce the number of free parameters to one. The observed fermion mass spectrum
is reproduced thanks to selection rules that discriminate among various
contributions. Bottom-tau Yukawa unification is preserved at leading order, but
there is no unification for the first two families. Interestingly, U(1)_F
charges alone do not determine the hierarchy, and can only give upper bounds on
the parametric suppression of the Yukawa operators.


title:
Aluminum-, Calcium- And Titanium-Rich Oxide Stardust In Ordinary
  Chondrite Meteorites

abstract:
  We report isotopic data for a total of 96 presolar oxide grains found in
residues of several unequilibrated ordinary chondrite meteorites. Identified
grain types include Al2O3, MgAl2O4, hibonite (CaAl12O19) and Ti oxide. This
work greatly increases the presolar hibonite database, and is the first report
of presolar Ti oxide. O-isotopic compositions of the grains span previously
observed ranges and indicate an origin in red giant and asymptotic giant branch
(AGB) stars of low mass (<2.5 MSun) for most grains. Cool bottom processing in
the parent AGB stars is required to explain isotopic compositions of many
grains. Potassium-41 enrichments in hibonite grains are attributable to in situ
decay of now-extinct 41Ca. Inferred initial 41Ca/40Ca ratios are in good
agreement with model predictions for low-mass AGB star envelopes, provided that
ionization suppresses 41Ca decay. Stable Mg and Ca isotopic ratios of most of
the hibonite grains reflect primarily the initial compositions of the parent
stars and are generally consistent with expectations for Galactic chemical
evolution, but require some local interstellar chemical inhomogeneity. Very
high 17O/16O or 25Mg/24Mg ratios suggest an origin for some grains in binary
star systems where mass transfer from an evolved companion has altered the
parent star compositions. A supernova origin for the hitherto enigmatic
18O-rich Group 4 grains is strongly supported by multi-element isotopic data
for two grains. The Group 4 data are consistent with an origin in a single
supernova in which variable amounts of material from the deep 16O-rich interior
mixed with a unique end-member mixture of the outer layers. The Ti oxide grains
primarily formed in low-mass AGB stars. They are smaller and rarer than
presolar Al2O3, reflecting the lower abundance of Ti than Al in AGB envelopes.


title:
A predictive A4 model, Charged Lepton Hierarchy and Tri-bimaximal Sum
  Rule

abstract:
  We propose a novel A4 model in which the Tri-Bimaximal (TB) neutrino mixing
and the charged lepton mass hierarchy are reproduced simultaneously. At leading
order, the residual symmetry of the neutrino sector is Z2 x Z2 which guarantees
the TB mixing without adjusting ad hoc free parameters. In the charged lepton
sector, one of the previous Z2 is maximally broken and the resulting mass
matrix is nearly diagonal and hierarchical. A natural mechanism for the
required vacuum alignment is given with the help of the supersymmetry and an
abelian symmetry factor. In our model, subleading effects which could lead to
appreciable deviations from TB mixing are very restrictive giving rise to
possible next-to-leading predictions. From an explicit example, we show that
our ``constrained'' A4 model is a natural framework, based on symmetry
principle, to incorporate the TB sum rule:
sin^2(\theta_{12})=1/3+2\sqrt{2}(cos(\delta) sin(\theta_{13})/3).


title: Spinning rough disk moving in a rarefied medium

abstract:
  A spinning rough disk moves through a rarefied medium on the plane. The
roughness is formed by small cavities on the disk boundary. The medium is so
rare that mutual interaction of particles can be neglected. All collisions of
particles with the disk are perfectly elastic; there may happen multiple
collisions in the cavities. We calculate the force of resistance acting on the
body and examine how it depends on the kind of roughness (shape of the
cavities). We show that the nonzero transversal component of the force
generally appears, resulting in deflection of the disk trajectory. In several
simple cases the trajectory is determined. We compare our results with the ones
known in the literature. It is known that there is a transversal force acting
on a spinning body (most often a sphere or a cylinder) moving in a rarefied
gas, due to nonelastic interaction of gas particles with the body. We propose
another mechanism of creating the transversal force, resulting from multiple
reflections of particles from the body.


title: Analytic Functions of a General Matrix Variable

abstract:
  Recent innovations on the differential calculus for functions of
non-commuting variables, begun for a quaternionic variable, are now extended to
the case of a general matrix over the complex numbers. The expansion of
F(X+Delta) is given to first order in Delta for general matrix variables X and
Delta that do not commute with each other.


title: Interface magnetism in Fe2O3/FeTiO3-heterostructures

abstract:
  To resolve the microscopic origin of magnetism in the Fe2O3/FeTiO3-system, we
have performed density functional theory calculations taking into account
on-site Coulomb repulsion. By varying systematically the concentration,
distribution and charge state of Ti in a hematite host, we compile a phase
diagram of the stability with respect to the end members and find a clear
preference to form layered arrangements as opposed to solid solutions. The
charge mismatch at the interface is accommodated through Ti4+ and a
disproportionation in the Fe contact layer into Fe2+, Fe3+, leading to
uncompensated moments in the contact layer and giving first theoretical
evidence for the lamellar magnetism hypothesis. This interface magnetism is
associated with impurity levels in the band gap showing halfmetallic behavior
and making Fe2O3/FeTiO3 heterostructures prospective materials for spintronics
applications.


title: Superconductivity in Multilayer Perovskite: Weak Coupling Analysis

abstract:
  We investigate the superconductivity of a three-dimensional d-p model with a
multilayer perovskite structure on the basis of the second-order perturabation
theory within the weak coupling framework. Our model has been designed with
multilayer high-$T_c$ superconducting cuprates in mind. In our model, multiple
Fermi surfaces appear, and the component of a superconducting gap function
develops on each band. We have found that the multilayer structure can
stabilize the superconductivity in a wide doping range.


title: Spitzer-IRAC Search for Companions to Nearby, Young M Dwarfs

abstract:
  We present the results of a survey of nearby, young M stars for wide low-mass
companions with IRAC on the Spitzer Space Telescope. We observed 40 young M
dwarfs within 20 pc of the Sun, selected through X-ray emission criteria. A
total of 10 candidate companions were found with IRAC colors consistent with T
dwarfs. Extensive ground-based NIR follow-up observations rejected all these
candidates. Two additional candidates were discovered via common proper motion
measurements, one of which was rejected as a background object and the other is
a bona fide companion to GJ 2060, a member of the AB Doradus moving group.


title:
Characterization of Compact Subsets of $\mathcal{A}^p$ with Respect to
  Weak Topology

abstract:
  In this brief article we characterize the relatively compact subsets of
$\mathcal{A}^p$ for the topology $\sigma(\mathcal{A}^p,\mathcal{R}^q)$ (see
below), by the weak compact subsets of $L^p$ . The spaces $\mathcal{R}^q$
endowed with the weak topology induced by $\mathcal{A}^p$, was recently
employed to create the convex risk theory of random processes. The weak compact
sets of $\mathcal{A}^p$ are important to characterize the so-called Lebesgue
property of convex risk measures, to give a complete description of the Makcey
topology on $\mathcal{R}^q$ and for their use in the optimization theory.


title:
Analytical solution for optimal squeezing of wave packet of a trapped
  quantum particle

abstract:
  Optimal control problem with a goal to squeeze wave packet of a trapped
quantum particle is considered and solved analytically using adiabatic
approximation. The analytical solution that drives the particle into a highly
localized final state is presented for a case of an infinite well trapping
potential. The presented solution may be applied to increase the resolution of
atom lithography.


title: Sub-Rayleigh Quantum Imaging

abstract:
  No imaging apparatus can produce perfect images: spatial resolution is
limited by the Rayleigh diffraction bound that is a consequence of the imager's
finite spatial extent. We show some N-photon strategies that permit resolution
of details that are smaller than this bound, attaining either a 1/sqrt(N)
enhancement (standard quantum limit) or a 1/N enhancement (Heisenberg limit)
over standard techniques. In the incoherent imaging regime, the methods
presented are loss resistant, because they can be implemented with
classical-state light sources. Our results may be of importance in many
applications: microscopy, telescopy, lithography, metrology, etc.


title:
Calculations of Trapping and Desorption in Heavy Atom Collisions with
  Surfaces

abstract:
  Calculations are carried out for the scattering of heavy rare gas atoms with
surfaces using a recently developed classical theory that can track particles
trapped in the physisorption potential well and follow them until ultimate
desorption. Comparisons are made with recent experimental data for xenon
scattering from molten gallium and indium, systems for which the rare gas is
heavier than the surface atoms. The good agreement with the data obtained for
both time-of-flight energy-resolved spectra and for total scattered angular
distributions yields an estimate of the physisorption well depths for the two
systems.


title: Forcing the Strong Lefschetz and the Maximal Rank Properties

abstract:
  Three basic properties that standard graded artinian $k$-algebras may or may
not enjoy are the Weak and Strong Lefschetz Properties and the Maximal Rank
Property (respectively WLP, SLP, and MRP).
  In this paper we will assume that the base field $k$ has characteristic zero.
It is known that SLP implies MRP, which in turn implies WLP, but that both
implications are strict. However, it surprisingly turned out that the set of
Hilbert functions admitting any algebras with WLP coincides with the
corresponding set for SLP (and therefore with that for MRP). J. Migliore and
the first author, using Green's theorem and a result of Wiebe, characterized
the Hilbert functions forcing all algebras to enjoy WLP. The purpose of this
note is to prove the corresponding characterizations for both SLP and MRP.
Unsurprisingly (or surprisingly??), the two characterizations coincide, but
they define a class of Hilbert functions strictly smaller than that determined
for WLP.
  Our methods include the Herzog-Popescu theorem on quotients of $k$-algebras
modulo a general form, a result of Wiebe, and gins and stable ideals. At the
end, we will also discuss the importance of assuming that the characteristic be
zero, and we will exhibit a class of codimension 2 monomial complete
intersections for which SLP (but not MRP) fails in positive characteristic.


title: Cosmological Constraints from Hubble Parameter on f(R) Cosmologies

abstract:
  Modified $f(R)$ gravity in the Palatini approach has been presently applied
to Cosmology as a realistic alternative to dark energy. In this concern, a
number of authors have searched for observational constraints on several $f(R)$
gravity functional forms using mainly data of type Ia supenovae (SNe Ia),
Cosmic Microwave Background ({\rm CMB}) radiation and Large Scale Structure
({\rm LSS}). In this paper, by considering a homogeneous and isotropic flat
universe, we use determinations of the Hubble function $H(z)$, which are based
on differential age method, to place bounds on the free parameters of the $f(R)
= R - \beta/R^{n}$ functional form. We also combine the $H(z)$ data with
constraints from Baryon Acoustic Oscillations ({\rm BAO}) and {\rm CMB}
measurements, obtaining ranges of values for $n$ and $\beta$ in agreement with
other independent analyses. We find that, for some intervals of $n$ and
$\beta$, models based on $f(R) = R - \beta/R^{n}$ gravity in the Palatini
approach, unlike the metric formalism, can produce the sequence of
radiation-dominated, matter-dominated, and accelerating periods without need of
dark energy.


title:
Two Dimensional Incompressible Ideal Flow Around a Thin Obstacle Tending
  to a Curve

abstract:
  In this work we study the asymptotic behavior of solutions of the
incompressible two-dimensional Euler equations in the exterior of a single
smooth obstacle when the obstacle becomes very thin tending to a curve. We
extend results by Iftimie, Lopes Filho and Nussenzveig Lopes, obtained in the
context of an obstacle tending to a point, see [Comm. PDE, {\bf 28} (2003),
349-379].


title: High Temperature Superconductivity and Effective Gravity

abstract:
  We argue that an approach involving effective gravity could play a crucial
role in elucidating the properties of the high temperature superconducting
materials. In particular we propose that the high critical temperature might be
naturally explained in a framework constructed as a direct condensed matter
analog of the Randall-Sundrum approach to a geometrization of the hierarchy
problem in high-energy physics.


title: Soliton response to transient trap variations

abstract:
  The response of bright and dark solitons to rapid variations in an expulsive
longitudinal trap is investigated. We concentrate on the effect of transient
changes in the trap frequency in the form of temporal delta kicks and the
hyperbolic cotangent functions. Exact expressions are obtained for the soliton
profiles. This is accomplished using the fact that a suitable linear
Schrodinger stationary state solution in time can be effectively combined with
the solutions of non-linear Schrodinger equation, for obtaining solutions of
the Gross-Pitaevskii equation with time dependent scattering length in a
harmonic trap. Interestingly, there is rapid pulse amplification in certain
scenarios.


title: Dynamics in a coupled-cavity array

abstract:
  The dynamics of a system composed of two coupled optical cavities, each
containing a single two-level atom, is studied over a wide range of detuning
and coupling values. A description of the field in terms of delocalized modes
reveals that the detuning between the atoms and these modes is controlled by
the coupling between the cavities; this detuning in turn governs the nature of
the dynamics. If the atoms are highly detuned from both delocalized field
modes, the dynamics becomes dispersive and an excitation may be transferred
from the first atom to the second without populating the field. In the case of
resonance between the atoms and one of the delocalized modes, state transfer
between the atoms requires intermediate excitation of the field. Thus the
interaction between the two atoms can be controlled by adjusting the coupling
between the cavities.


title:
Physical parameters for Orion KL from modelling its ISO high resolution
  far-IR CO line spectrum

abstract:
  As part of the first high resolution far-IR spectral survey of the Orion KL
region (Lerate et al. 2006), we observed 20 CO emission lines with Jup=16 to
Jup=39 (upper levels from approx 752 K to 4294 K above the ground state).
Observations were taken using the Long Wavelength Spectrometer (LWS) on board
the Infrared Space Observatory (ISO), in its high resolution Fabry-Perot (FP)
mode (approx 33 km s$^{-1}$). We present here an analysis of the final
calibrated CO data, performed with a more sophisticated modelling technique
than hitherto, including a detailed analysis of the chemistry, and discuss
similarities and differences with previous results. The inclusion of chemical
modelling implies that atomic and molecular abundances are time-predicted by
the chemistry. This provides one of the main differences with previous studies
in which chemical abundances needed to be assumed as initial condition. The
chemistry of the region is studied by simulating the conditions of the
different known components of the KL region: chemical models for a hot core, a
plateau and a ridge are coupled with an accelerated Lambda-iteration
(ALI)radiative transfer model to predict line fluxes and profiles. We conclude
that the CO transitions with 18<Jup<25 mainly arise from a hot core of diameter
0.02 pc and a density of 10$^{7}$ cm$^{-3}$ rather from the plateau as previous
studies had indicated.


title:
Dynamical effects of self-generated magnetic fields in cosmic ray
  modified shocks

abstract:
  Recent observations of greatly amplified magnetic fields ($\delta B/B\sim
100$) around supernova shocks are consistent with the predictions of the
non-linear theory of particle acceleration (NLT), if the field is generated
upstream of the shock by cosmic ray induced streaming instability. The high
acceleration efficiencies and large shock modifications predicted by NLT need
however to be mitigated to confront observations, and this is usually assumed
to be accomplished by some form of turbulent heating. We show here that
magnetic fields with the strength inferred from observations have an important
dynamical role on the shock, and imply a shock modification substantially
reduced with respect to the naive unmagnetized case. The effect appears as soon
as the pressure in the turbulent magnetic field becomes comparable with the
pressure of the thermal gas. The relative importance of this unavoidable effect
and of the poorly known turbulent heating is assessed. More specifically we
conclude that even in the cases in which turbulent heating may be of some
importance, the dynamical reaction of the field cannot be neglected, as instead
is usually done in most current calculations.


title:
Uniform observability of hidden Markov models and filter stability for
  unstable signals

abstract:
  A hidden Markov model is called observable if distinct initial laws give rise
to distinct laws of the observation process. Observability implies stability of
the nonlinear filter when the signal process is tight, but this need not be the
case when the signal process is unstable. This paper introduces a stronger
notion of uniform observability which guarantees stability of the nonlinear
filter in the absence of stability assumptions on the signal. By developing
certain uniform approximation properties of convolution operators, we
subsequently demonstrate that the uniform observability condition is satisfied
for various classes of filtering models with white-noise type observations.
This includes the case of observable linear Gaussian filtering models, so that
standard results on stability of the Kalman--Bucy filter are obtained as a
special case.


title: Improved Spin-Dependent WIMP Limits from a Bubble Chamber

abstract:
  Bubble Chambers provided the dominant particle detection technology in
accelerator experiments for several decades, eventually falling into disuse
with the advent of other techniques. We report here on the first period of
operation of an ultra-clean, room-temperature bubble chamber containing 1.5 kg
of superheated CF$_{3}$I, a target maximally sensitive to spin-dependent and
-independent Weakly Interacting Massive Particle (WIMP) couplings. An exposure
in excess of 250 kg-days is obtained, with a live-time fraction reaching 80%.
This illustrates the ability to employ bubble chambers in a new realm, the
search for dark matter particles. Improved limits on the spin-dependent
WIMP-proton scattering cross section are extracted from this first period. An
extreme intrinsic insensitivity to the backgrounds commonly limiting these
experiments (a rejection factor for photon-induced electrons of $\sim10^{-10}$)
has been measured in operating conditions leading to the detection of
low-energy nuclear recoils such as those expected from WIMPs.


title: Hitting Time Statistics and Extreme Value Theory

abstract:
  We consider discrete time dynamical systems and show the link between Hitting
Time Statistics (the distribution of the first time points land in
asymptotically small sets) and Extreme Value Theory (distribution properties of
the partial maximum of stochastic processes). This relation allows to study
Hitting Time Statistics with tools from Extreme Value Theory, and vice versa.
We apply these results to non-uniformly hyperbolic systems and prove that a
multimodal map with an absolutely continuous invariant measure must satisfy the
classical extreme value laws (with no extra condition on the speed of mixing,
for example). We also give applications of our theory to higher dimensional
examples, for which we also obtain classical extreme value laws and exponential
hitting time statistics (for balls). We extend these ideas to the subsequent
returns to asymptotically small sets, linking the Poisson statistics of both
processes.


title: Bose-Einstein condensates in disordered potentials

abstract:
  The interplay between disorder and interactions is a "leit-motiv" of
condensed matter physics, since it constitutes the driving mechanism of the
metal-insulator transition. Bose-Einstein condensates in optical potentials are
proving to be powerful tools to quantum simulate disordered systems. We will
review the main experimental and theoretical results achieved in the last few
years in this rapidly developing field.


title:
Dynamic Evolution of a Quasi-Spherical General Polytropic Magnetofluid
  with Self-Gravity

abstract:
  In various astrophysical contexts, we analyze self-similar behaviours of
magnetohydrodynamic (MHD) evolution of a quasi-spherical polytropic magnetized
gas under self-gravity with the specific entropy conserved along streamlines.
In particular, this MHD model analysis frees the scaling parameter $n$ in the
conventional polytropic self-similar transformation from the constraint of
$n+\gamma=2$ with $\gamma$ being the polytropic index and therefore
substantially generalizes earlier analysis results on polytropic gas dynamics
that has a constant specific entropy everywhere in space at all time. On the
basis of the self-similar nonlinear MHD ordinary differential equations, we
examine behaviours of the magnetosonic critical curves, the MHD shock
conditions, and various asymptotic solutions. We then construct global
semi-complete self-similar MHD solutions using a combination of analytical and
numerical means and indicate plausible astrophysical applications of these
magnetized flow solutions with or without MHD shocks.


title: How hot are expanding universes ?

abstract:
  A way to address the conundrum of Quantum Gravity is to illustrate the
potentially fundamental interplay between quantum field theory, curved
space-times physics and thermodynamics. So far, when studying moving quantum
systems in the vacuum, the only known perfectly thermal temperatures are those
obtained for constant (or null) accelerations $A$ in constant (or null) Hubble
parameters $H$ space-times. In this Letter, restricting ourselves to
conformally coupled scalar fields, we present the most comprehensive expression
for the temperature undergone by a moving observer in the vacuum, valid for any
time-dependent linear accelerations and Hubble parameters: $T=\sqrt{A^2 + H^2 +
2 \dot H\dot t}/{2\pi}$ where $\dot t=\d t/\d\t$ is the motion's Lorentz
factor. The inequivalence between a constant $T$ and actual thermality is
explained. As a byproduct, all the Friedman universes for which observers at
rest feel the vacuum as a thermal bath are listed.


title: Water at an electrochemical interface - a simulation study

abstract:
  The results of molecular dynamics simulations of the properties of water in
an aqueous ionic solution close to an interface with a model metallic electrode
are described. In the simulations the electrode behaves as an ideally
polarizable hydrophilic metal, supporting image charge interactions with
charged species, and it is maintained at a constant electrical potential with
respect to the solution so that the model is a textbook representation of an
electrochemical interface through which no current is passing. We show how
water is strongly attracted to and ordered at the electrode surface. This
ordering is different to the structure that might be imagined from continuum
models of electrode interfaces. Further, this ordering significantly affects
the probability of ions reaching the surface. We describe the concomitant
motion and configurations of the water and ions as functions of the electrode
potential, and we analyze the length scales over which ionic atmospheres
fluctuate. The statistics of these fluctuations depend upon surface structure
and ionic strength. The fluctuations are large, sufficiently so that the mean
ionic atmosphere is a poor descriptor of the aqueous environment near a metal
surface. The importance of this finding for a description of electrochemical
reactions is examined by calculating, directly from the simulation, Marcus free
energy profiles for transfer of charge between the electrode and a redox
species in the solution and comparing the results with the predictions of
continuum theories. Significant departures from the electrochemical textbook
descriptions of the phenomenon are found and their physical origins are
characterized from the atomistic perspective of the simulations.


title:
On the galaxy stellar mass function, the mass-metallicity relation, and
  the implied baryonic mass function

abstract:
  A comparison between published field galaxy stellar mass functions (GSMFs)
shows that the cosmic stellar mass density is in the range 4--8 per cent of the
baryon density (assuming Omega_b = 0.045). There remain significant sources of
uncertainty for the dust correction and underlying stellar mass-to-light ratio
even assuming a reasonable universal stellar initial mass function. We
determine the z < 0.05 GSMF using the New York University - Value-Added Galaxy
Catalog sample of 49968 galaxies derived from the Sloan Digital Sky Survey and
various estimates of stellar mass. The GSMF shows clear evidence for a low-mass
upturn and is fitted with a double Schechter function that has alpha_2 =~ -1.6.
At masses below ~ 10^8.5 Msun, the GSMF may be significantly incomplete because
of missing low surface-brightness galaxies. One interpretation of the stellar
mass-metallicity relation is that it is primarily caused by a lower fraction of
available baryons converted to stars in low-mass galaxies. Using this
principal, we determine a simple relationship between baryonic mass and stellar
mass and present an `implied baryonic mass function'. This function has a
faint-end slope, alpha_2 =~ -1.9. Thus, we find evidence that the slope of the
low-mass end of the galaxy mass function could plausibly be as steep as the
halo mass function. We illustrate the relationship between halo baryonic mass
function --> galaxy baryonic mass function --> GSMF. This demonstrates the
requirement for peak galaxy formation efficiency at baryonic masses ~ 10^11
Msun corresponding to a minimum in feedback effects. The baryonic-infall
efficiency may have levelled off at lower masses.


title: Strong coupling for planar ${\cal N}=4$ SYM theory: an all-order result

abstract:
  We propose a scheme for determining a generalised scaling function, namely
the Sudakov factor in a peculiar double scaling limit for high spin and large
twist operators belonging to the $sl(2)$ sector of planar ${\cal N}=4$ SYM. In
particular, we perform explicitly the all-order computation at strong 't Hooft
coupling regarding the first (contribution to the) generalised scaling
function. Moreover, we compare our asymptotic results with the numerical
solutions finding a very good agreement and evaluate numerically the
non-asymptotic contributions. Eventually, we illustrate the agreement and
prediction on the string side.


title: Optimal non-linear passage through a quantum critical point

abstract:
  We analyze the problem of optimal adiabatic passage through a quantum
critical point. We show that to minimize the number of defects the tuning
parameter should be changed as a power-law in time. The optimal power is
proportional to the logarithm of the total passage time multiplied by universal
critical exponents characterizing the phase transition. We support our results
by the general scaling analysis and by explicit calculations for the transverse
field Ising model.


title: X-ray flares and their relation to the inner engine activity of GRBs

abstract:
  Flares overlaid on the smooth power-law decay of Swift X-ray afterglows are
rather common, appearing in roughly half the observed light curves. They are a
manifestation of the late time activity of the inner engine, since their
temporal evolution is too fast to be linked to activity taking place in the
external shock blastwave. In this paper we show that the energy emitted in the
form of flares decreases with time as a power-law. We discuss several
possibilities in which the flares can be powered and the source of the observed
variability. We show that late time accretion from a disk can provide the
necessary energy input in both classes of short duration and long duration
gamma-ray bursts.


title: Detecting the Milky Way's Dark Disk

abstract:
  In LambdaCDM, massive satellites are dragged into the disk-plane by dynamical
friction where they dissolve into a stellar thick disk and a more massive dark
matter disk. The distinctive kinematics of the dark disk matches the stars that
also entered in the satellites. The lower velocities of the dark disk with
respect to the Earth enhances detection rates at low recoil energy. For WIMP
masses > 50 GeV/c^2, the detection rate increases by up to a factor of 3 in the
5 - 20 keV recoil energy range. Comparing this with rates at higher energy will
improve constraints on the WIMP mass, particularly for masses > 100 GeV/c^2.
The annual modulation signal of the dark disk is significantly boosted and its
modulation phase is shifted by ~3 weeks relative to the dark halo. The
variation of the observed phase with recoil energy can also be used to
determine the WIMP mass once the dark disk properties are fixed by future
astronomical surveys. The constraints on the WIMP interaction cross section
from current experiments improve by factors of 1.4 to 3.5 when a typical
contribution from the dark disk is included.


title: A Groebner basis for the secant ideal of the second hypersimplex

abstract:
  We determine a Groebner basis for the secant ideal of the toric ideal
associated to the second hypersimplex, with respect to any circular term order.
The Groebner basis of the secant ideal requires polynomials of odd degree up to
n. This shows that the circular term order is 2-delightful, resolving a
conjecture of Drton, Sturmfels, and the author. The proof uses Groebner
degenerations for secant ideals, combinatorial characterizations of the secant
ideals of monomial ideals, and the relations between secant ideals and
prolongations.


title: Diversity under variability and extreme variability of environments

abstract:
  We conducted an investigation of the effect that extreme variability of the
individual's environment has in the individual's adaptability and, in general,
in the co-evolution of a population. First we assume that the individuals are a
kind of perceptrons with a given memory size that adapt to their environment;
second we consider co-evolution not only of the individual actions but also of
the memory size, depending on the individual's fitness; and third we assume
strong variability of the environment. We show that changes in the intensity of
the environmental fluctuations introduce a phase transition in the frequency of
cooperators and the diversity of the population. We also find out that extreme
variability of the environment induces changes in the critical exponents and
that this variability can promote more diversity in the population.


title: Solving the LHC Inverse Problem with Dark Matter Observations

abstract:
  We investigate the utility of cosmological and astrophysical observations for
distinguishing between supersymmetric theories. In particular we consider 276
pairs of models that give rise to nearly identical patterns of observables at
hadron colliders. Despite inherent uncertainties in such things as the local
halo density model, or background rates from astrophysical sources, we find
observations associated with stable relic neutralinos can be a surprisingly
effective discriminant between candidate theories. We focus attention on
neutralino scattering experiments (direct detection of relic neutralinos) and
observations of gamma-rays from relic neutralino annihilation (indirect
detection experiments). With extremely conservative physics assumptions and
background estimates we find 101 of the 276 degenerate pairs can be
distinguished. Using slightly more optimistic assumptions about background
rates increases this number to 186 of the 276 pairs. In the direct detection
arena the ability to distinguish between models will be dependent on further
progress in addressing uncertainty in nuclear matrix elements. For observations
in the indirect detection arena we discuss the sensitivity of these results to
additional assumptions made about the cosmological density of neutralinos and
the galactic halo profile. We also comment on the complementarity of this study
to recent work investigating these same pairs at a 500 GeV linear collider.


title: Jacobi's Principle and the Disappearance of Time

abstract:
  Jacobi's action principle is known to lead to a problem of time. For example,
the timelessness of the Wheeler-DeWitt equation can be seen as resulting from
using Jacobi's principle to define the dynamics of 3-geometries through
superspace. In addition, using Jacobi's principle for non-relativistic
particles is equivalent classically to Newton's theory but leads to a
time-independent Schrodinger equation upon Dirac quantization. In this paper,
we study the mechanism for the disappearance of time as a result of using
Jacobi's principle in these simple particle models. We find that the path
integral quantization very clearly elucidates the physical mechanism for the
timeless of the quantum theory as well as the emergence of duration at the
classical level. Physically, this is the result of a superposition of clocks
which occurs in the quantum theory due to a sum over all histories.
Mathematically, the timelessness is related to how the gauge fixing functions
impose the boundary conditions in the path integral.


title:
A study of the quantum classical crossover in the spin dynamics of the
  2D S=5/2 antiferromagnet Rb2MnF4: neutron scattering, computer simulations,
  and analytic theories

abstract:
  We report comprehensive inelastic neutron scattering measurements of the
magnetic excitations in the 2D spin-5/2 Heisenberg antiferromagnet Rb2MnF4 as a
function of temperature from deep in the Neel ordered phase up to paramagnetic,
0.13 < kBT/4JS < 1.4. Well defined spin-waves are found for wave-vectors larger
than the inverse correlation length $\eta^{-1}$ for temperatures up to near the
Curie-Weiss temperature, $\Theta_{CW}$. For wave-vectors smaller than
$\eta^{-1}$, relaxational dynamics occurs. The observed renormalization of
spin-wave energies, and evolution of excitation line-shapes, with increasing
temperature are quantitatively compared with finite-temperature spin-wave
theory, and computer simulations for classical spins. Random phase
approximation calculations provide a good description of the low-temperature
renormalisation of spin-waves. In contrast, lifetime broadening calculated
using the first Born approximation shows, at best, modest agreement around the
zone boundary at low temperatures. Classical dynamics simulations using an
appropriate quantum-classical correspondence were found to provide a good
description of the intermediate- and high-temperature regimes over all
wave-vector and energy scales, and the crossover from quantum to classical
dynamics observed around $\Theta_{CW}/S$, where the spin S=5/2. A
characterisation of the data over the whole wave-vector/energy/temperature
parameter space is given. In this, $T^2$ behaviour is found to dominate the
wave-vector and temperature dependence of the line widths over a large
parameter range, and no evidence of hydrodynamic behaviour or dynamical scaling
behaviour found within the accuracy of the data sets.


title: Supersymmetric Boundary Conditions in N=4 Super Yang-Mills Theory

abstract:
  We study boundary conditions in N=4 super Yang-Mills theory that preserve
one-half the supersymmetry. The obvious Dirichlet boundary conditions can be
modified to allow some of the scalar fields to have a ``pole'' at the boundary.
The obvious Neumann boundary conditions can be modified by coupling to
additional fields supported at the boundary. The obvious boundary conditions
associated with orientifolds can also be generalized. In preparation for a
separate study of how electric-magnetic duality acts on these boundary
conditions, we explore moduli spaces of solutions of Nahm's equations that
appear in the presence of a boundary. Though our main interest is in boundary
conditions that are Lorentz-invariant (to the extent possible in the presence
of a boundary), we also explore non-Lorentz-invariant but half-BPS deformations
of Neumann boundary conditions. We make preliminary comments on the action of
electric-magnetic duality, deferring a more serious study to a later paper.


title:
Stabilisation of long-period periodic orbits using time-delayed feedback
  control

abstract:
  The Pyragas method of feedback control has attracted much interest as a
method of stabilising unstable periodic orbits in a number of situations. We
show that a time-delayed feedback control similar to the Pyragas method can be
used to stabilise periodic orbits with arbitrarily large period, specifically
those resulting from a resonant bifurcation of a heteroclinic cycle. Our
analysis reduces the infinite-dimensional delay-equation governing the system
with feedback to a three-dimensional map, by making certain assumptions about
the form of the solutions. The stability of a fixed point in this map
corresponds to the stability of the periodic orbit in the flow, and can be
computed analytically. We compare the analytic results to a numerical example
and find very good agreement.


title: The CMB cold spot: texture, cluster or void?

abstract:
  The non-Gaussian cold spot found in the WMAP data has created controversy
about its origin. Here we calculate the Bayesian posterior probability ratios
for three different models that could explain the cold spot. A recent work
claimed that the Spot could be caused by a cosmic texture, while other papers
suggest that it could be due to the gravitational effect produced by an
anomalously large void. Also the Sunyaev-Zeldovich effect caused by a cluster
is taken into account as a possible origin. We perform a template fitting on a
20 degrees radius patch centered at Galactic coordinates (b = -57circ, l = 209)
and calculate the posterior probability ratios for the void and
Sunyaev-Zeldovich models, comparing the results to those obtained with
textures. Taking realistic priors for the parameters, the texture
interpretation is favored, while the void and Sunyaev-Zeldovich hypotheses are
discarded. The temperature decrement produced by voids or clusters is
negligible considering realistic values for the parameters.


title: The physics of eight flavours

abstract:
  We study Quantum Chromodynamics with eight flavours by use of lattice
simulations and present evidence that the theory still breaks chiral symmetry
in the zero temperature, continuum limit. This confirms that the lower end of
the conformal window of QCD lies above Nf = 8.


title:
A Note about proving non-$\Gamma$ under a finite non-microstates free
  Fisher information Assumption

abstract:
  We prove that if $X_{1},...,X_{n} (n >1)$ are selfadjoints in a
$W^{*}$-probability space with finite non-microstates free Fisher information,
then the von Neumann algebra $W^{*}(X_{1},...,X_{n})$ they generate doesn't
have property $\Gamma$ (especially is not amenable). This is an analog of a
well-known result of Voiculescu for microstates free entropy. We also prove
factoriality under finite non-microstates entropy.


title:
Janus Configurations, Chern-Simons Couplings, And The Theta-Angle in N=4
  Super Yang-Mills Theory

abstract:
  We generalize the half-BPS Janus configuration of four-dimensional N=4 super
Yang-Mills theory to allow the theta-angle, as well as the gauge coupling, to
vary with position. We show that the existence of this generalization is
closely related to the existence of novel three-dimensional Chern-Simons
theories with N=4 supersymmetry. Another closely related problem, which we also
elucidate, is the D3-NS5 system in the presence of a four-dimensional
theta-angle.


title:
On Finitely Generated Models of Theories with at Most Countably Many
  Nonisomorphic Finitely Generated Models

abstract:
  We study finitely generated models of countable theories, having at most
countably many nonisomorphic finitely generated models. We intro- duce a notion
of rank of finitely generated models and we prove, when T has at most countably
many nonisomorphic finitely generated models, that every finitely generated
model has an ordinal rank. This rank is used to give a prop- erty of finitely
generated models analogue to the Hopf property of groups and also to give a
necessary and sufficient condition for a finitely generated model to be prime
of its complete theory. We investigate some properties of limit groups of
equationally noetherian groups, in respect to their ranks.


title:
Thickness dependence of the exchange bias in epitaxial manganite
  bilayers

abstract:
  Exchange bias has been studied in a series of La2/3Ca1/3MnO3 / La1/3Ca2/3MnO3
bilayers grown on (001) SrTiO3 substrates by ozone-assisted molecular beam
epitaxy. The high crystalline quality of the samples and interfaces has been
verified using high-resolution X-ray diffractometry and Z-contrast scanning
transmission electron microscopy with electron energy loss spectroscopy. The
dependence of exchange bias on the thickness of the antiferromagnetic layer has
been investigated. A critical value for the onset of the hysteresis loop shift
has been determined. An antiferromagnetic anisotropy constant has been obtained
by fitting the results to the generalized Meiklejohn-Bean model.


title: Minimal volume $k$-point lattice $d$-simplices

abstract:
  We extend the results of Bey, Hen, and Wills
(http://arxiv.org/abs/math/0606089). In this paper, we show that, up to
equivalence under unimodular transformations, there is exactly one class of
$d$-simplices having $k \ge 1$ interior lattice points and minimal volume
$\frac{1}{d!}(dk+1)$.


title: Locally Metric Spacetimes

abstract:
  Spacetimes have conventionally been described by a global Lorentzian metric
on a differentiable four-manifold. Herein we explore the possibility of
spacetimes defined by a connection, which is locally but not globally
Levi-Civita. The general method of obtaining such connections is presented for
the non-degenerate case followed by an example that modifies the
Robertson-Walker spacetimes for flat spacelike hypersurfaces.


title:
The continuous behavior of the numeraire portfolio under small changes
  in information structure, probabilistic views and investment constraints

abstract:
  The numeraire portfolio in a financial market is the unique positive wealth
process that makes all other nonnegative wealth processes, when deflated by it,
supermartingales. The numeraire portfolio depends on market characteristics,
which include: (a) the information flow available to acting agents, given by a
filtration; (b) the statistical evolution of the asset prices and, more
generally, the states of nature, given by a probability measure; and (c)
possible restrictions that acting agents might be facing on available
investment strategies, modeled by a constraints set. In a financial market with
continuous-path asset prices, we establish the stable behavior of the numeraire
portfolio when each of the aforementioned market parameters is changed in an
infinitesimal way.


title:
NEMO-\onde: a submarine station for real-time monitoring of acoustic
  background installed at 2000 m depth in the Mediterranean Sea

abstract:
  The NEMO (NEutrino Mediterranean Observatory) Collaboration installed, 25 km
E offshore the port of Catania (Sicily) at 2000 m depth, an underwater
laboratory to perform long-term tests of prototypes and new technologies for an
underwater high energy neutrino km$^3$-scale detector in the Mediterranean Sea.
In this framework the collaboration deployed and successfully operated for
about two years, starting form January 2005, an experimental apparatus for
on-line monitoring of deep-sea noise. The station was equipped with 4
hydrophones and it is operational in the range 30 Hz - 43 kHz. This interval of
frequencies matches the range suitable for the proposed acoustic detection
technique of high energy neutrinos. Hydrophone signals were digitized
underwater at 96 kHz sampling frequency and 24 bits resolution. A custom
software was developed to record data on high resolution 4-channels digital
audio file. This paper deals with the data analysis procedure and first results
on the determination of sea noise sound pressure density curves. The stored
data library, consisting of more than 2000 hours of recordings, is a unique
tool to model underwater acoustic noise at large depth, to characterise its
variations as a function of environmental parameters, biological sources and
human activities (ship traffic, ...), and to determine the presence of
cetaceans in the area.


title: Nonlocal effects on penetration depth of FFLO d-wave superconductors

abstract:
  The penetration depth of FFLO d-wave superconductors is calculated, in
presence of additional magnetic field for both parallel and perpendicular to
the internal FFLO magnetic field, when the nonlocal effects are dominated. The
generalized Gorkov equations have been used to obtain the linearized response
kernel. It is shown that extra term added to total kernel with no spatially gap
is proportional to the momentum of FFLO Cooper pairs, Q. For the case parallel
to the internal FFLO magnetic field, below a crossover temperature T*, it is
shown that Lambda(T)-Lambda(0) is proportional to T^3 for both specular
reflecting and diffusive boundary. It is noted that both terms in penetration
depth with and without Q dependence have the same temperature dependence but
magnetic field dependence are different(the terms without and with Q dependence
are proportional to 1/h' and 1/(h'^2) respectively). Also nonlocal effect on
penetration depth of FFLO state in reign T>>T* obtains temperature dependence
T^4. Furthermore, when external magnetic test-field is perpendicular to
internal FFLO magnetic field, it is shown that nonlocal effects on penetration
depth give the same Q and temperature dependence as the parallel case but with
different internal and additional magnetic field dependences.


title: Preparing a highly degenerate Fermi gas in an optical lattice

abstract:
  We propose a method to prepare a sample of fermionic atoms in a
three-dimensional (3D) optical lattice at unprecedentedly low temperatures and
uniform filling factors. The process involves adiabatic loading of atoms into
multiple energy bands of an optical lattice followed by a filtering stage
whereby atoms from all but the ground band are removed. Of critical importance
is the use of a non-harmonic trapping potential, taken here to be the radial
profile of a high-order Laguerre-Gaussian laser beam, to provide external
confinement for the atoms. For realistic experimental parameters, this
procedure should produce samples with temperatures $\sim10^{-3}$ of the Fermi
temperature. This would allow the investigation of the low-temperature phase
diagram of the Fermi-Hubbard model as well as the initialization of a
high-fidelity quantum register.


title: Dead Zone Accretion Flows in Protostellar Disks

abstract:
  Planets form inside protostellar disks in a dead zone where the electrical
resistivity of the gas is too high for magnetic forces to drive turbulence. We
show that much of the dead zone nevertheless is active and flows toward the
star while smooth, large-scale magnetic fields transfer the orbital angular
momentum radially outward. Stellar X-ray and radionuclide ionization sustain a
weak coupling of the dead zone gas to the magnetic fields, despite the rapid
recombination of free charges on dust grains. Net radial magnetic fields are
generated in the magneto-rotational turbulence in the electrically conducting
top and bottom surface layers of the disk, and reach the midplane by Ohmic
diffusion. A toroidal component to the fields is produced near the midplane by
the orbital shear. The process is similar to the magnetization of the Solar
tachocline. The result is a laminar, magnetically-driven accretion flow in the
region where the planets form.


title: Testing the DGP model with gravitational lensing statistics

abstract:
  The self-accelerating braneworld model (DGP) seems to provide a simple
alternative to the the standard $\Lambda$CDM cosmology to explain the current
cosmic acceleration, which is strongly indicated by measurements of Type Ia
supernovae, as well as other concordant observations. In this work, we
investigate observational constraints on this scenario from gravitational
lensing statistics using the Cosmic Lens All-Sky Survey (CLASS) lensing sample.
We show that a large parameter space of the DGP model is in good agreement with
this radio source gravitational lensing sample. In the flat case,
$\Omega_\mathrm{K}=0$, the likelihood is maximized, ${\cal L}={\cal
L_\mathrm{max}}$, for $\1 = 0.30_{-0.11}^{+0.19}$. If we relax the prior on
$\Omega_\mathrm{K}$, the likelihood peaks at $\{\1,\2 \} \simeq \{0.29,
0.12\}$, just slightly in the region of open models. However the confidence
contours are pretty elongated so that we can not discard either close or flat
or open models


title:
The optimal approach of detecting stochastic gravitational wave from
  string cosmology using multiple detectors

abstract:
  String cosmology models predict a relic background of gravitational wave
produced during the dilaton-driven inflation. It's spectrum is most likely to
be detected by ground gravitational wave laser interferometers (IFOs), like
LIGO, Virgo, GEO, as the energy density grows rapidly with frequency. We show
the certain ranges of the parameters that underlying string cosmology model
using two approaches, associated with 5% false alarm and 95% detection rate.
The result presents that the approach of combining multiple pairs of IFOs is
better than the approach of directly combining the outputs of multiple IFOs for
LIGOH, LIGOL, Virgo and GEO.


title:
Low energy density correlation function of the degenerate unitary Fermi
  gas from epsilon expansion

abstract:
  Using $\epsilon$ expansion proposed in \cite{Nishida:2006br} we calculate
density correlation function of the degenerate Fermi gas at infinite scattering
length to next-to-leading order in $\epsilon$ for excitation energies below
quasi particle threshold. An expression for the low energy dynamic structure
function is derived.


title:
Quantum control of the hyperfine-coupled electron and nuclear spins in
  alkali atoms

abstract:
  We study quantum control of the full hyperfine manifold in the
ground-electronic state of alkali atoms based on applied radio frequency and
microwave fields. Such interactions should allow essentially decoherence-free
dynamics and the application of techniques for robust control developed for NMR
spectroscopy. We establish the conditions under which the system is
controllable in the sense that one can generate an arbitrary unitary on the
system. We apply this to the case of $^{133}$Cs with its $d=16$ dimensional
Hilbert space of magnetic sublevels in the $6S_{1/2}$ state, and design control
waveforms that generate an arbitrary target state from an initial fiducial
state. We develop a generalized Wigner function representation for this space
consisting of the direct sum of two irreducible representation of SU(2),
allowing us to visualize these states. The performance of different control
scenarios is evaluated based on the ability to generate high-fidelity operation
in an allotted time with the available resources. We find good operating points
commensurate with modest laboratory requirements.


title: The nature of Ho magnetism in multiferroic HoMnO3

abstract:
  Using x-ray resonant magnetic scattering and x-ray magnetic circular
dichroism, techniques that are element specific, we have elucidated the role of
Ho3+ in multiferroic HoMnO3. In zero field, Ho3+ orders antiferromagnetically
with moments aligned along the hexagonal c direction below 40 K, and undergoes
a transition to another magnetic structure below 4.5 K. In applied electric
fields of up to 1x10^7 V/m, the magnetic structure of Ho3+ remains unchanged.


title: Pairing correlations and effective mass

abstract:
  We study the effect of effective mass on pairing correlations in the ground
states of superfluid nuclei $^{124}$Sn and $^{136}$Sn. Various parameter sets
of Skyrme interactions and relativistic Lagrangians are adopted to study
pairing correlations across a wide range of effective mass. It is shown that
surface-type pairing interaction gives an almost constant pairing gap as a
function of the effective mass, while volume-type pairing interaction shows
rather strong dependence of the pairing gap upon the effective mass. The local
pair potentials of various effective interactions are also examined in relation
to the effective mass.


title:
On the giant magnon and spike solutions for strings on AdS$_3\times$
  S$^3$

abstract:
  We study solutions for the rotating strings on the sphere with a background
NS-NS field and on the Anti-de-Sitter spacetime. We show the existence of
magnon and single spike solutions on R$\times$S$^2$ in the presence of constant
magnetic field as two limiting cases. We also study the solution for strings on
AdS$_3\times$ S$^3$ with Melvin deformation. The dispersion relations among
various conserved charges are shown to receive finite corrections due to the
deformation parameter. We further study the rotating string on AdS$_3 \times$
S$^3$ geometry with two conserved angular momenta on S$^3$ and one spin along
the AdS$_3$. We show that there exists two kinds of solutions: a circular
string solution and a helical string. We find out the dispersion relation among
various charges and give physical interpretation of these solutions.


title: The Exceptionally Large Debris Disk around \gamma Ophiuchi

abstract:
  Spitzer images resolve the debris disk around \gamma Ophiuchi at both 24 and
70 um. The resolved images suggest a disk radius of ~520 AU at 70 um and >=260
AU at 24 um. The images, along with a consistent fit to the spectral energy
distribution of the disk from 20 to 350 um, show that the primary disk
structure is inclined by ~50 degree from the plane of the sky at a position
angle of 55+/-2 degree. Among a group of twelve debris disks that have similar
host star spectral types, ages and infrared fractional luminosities, the
observed sizes in the infrared and color temperatures indicate that evolution
of the debris disks is influenced by multiple parameters in addition to the
proto-planetary disk initial mass.


title: Holographic Dark Energy in Brans-Dicke Theory

abstract:
  In this paper, the holographic dark energy model is considered in Brans-Dicke
theory where the holographic dark energy density $\rho_{\Lambda} =3c^2
M^{2}_{pl} L^{-2}$ is replaced with $\rho_{h}=3c^2 \Phi(t)L^{-2}$. Here
$\Phi(t)=\frac{1}{8\pi G}$ is a time variable Newton constant. With this
replacement, it is found that no accelerated expansion universe will be
achieved when the Hubble horizon is taken as the role of IR cut-off. When the
event horizon is adopted as the IR cut-off, an accelerated expansion universe
is obtained. In this case, the equation of state of holographic dark energy
$w_h$ takes a modified form
$w_h=-{1/3}(1+\alpha+\frac{2}{c}\sqrt{\Omega_{h}})$. In the limit $\alpha\to
0$, the 'standard' holographic dark energy is recovered. In the holographic
dark energy dominated epoch, power-law and de Sitter time-space solutions are
obtained.


title: A Holographic QCD and Excited Baryons from String Theory

abstract:
  We study baryons of arbitrary isospin in a stringy holographic QCD model. In
this D4-D8 holographic setting, the flavor symmetry is promoted to a gauge
symmetry in the bulk, and produces, as KK modes of the gauge field, pions and
spin one mesons of low energy QCD. Baryons of arbitrary isospins are
represented as instanton solitons with isospin and spin quantum numbers locked,
in a manner similar to the Skyrmion model. The soliton picture leads to a
natural effective field theory of arbitrary baryons interacting with mesons.
Couplings of baryons to axial mesons, including pions, are dominated in the
large $N_c$ limit by a direct coupling to the flavor field strength in five
dimensions. We delineate the relevant couplings and determine their strengths.
This work generalizes part of hep-th/0701276 and arXiv:0705.2632 [hep-th] to
all excited baryons. Due to technical difficulties in introducing relativistic
higher spin fields, we perform all computations in the nonrelativistic regime,
which suffices for the leading $N_c$ predictions.


title:
Proper projective collineation in non-static spherically symmetric
  space-times

abstract:
  We investigate the proper projective collineation in non-static spherically
symmetric space-times using direct integration and algebraic techniques.
Studying projective collineation in the above space-times, it is shown that the
space-times which admit proper projective collineations turn out to be very
special classes of static spherically symmetric space-times.


title:
Compact groups in theory and practice - I. The spatial properties of
  compact groups

abstract:
  We use a mock galaxy catalogue based upon the Millennium Run simulation to
investigate the intrinsic spatial properties of compact groups of galaxies. We
find that approximately 30% of galaxy associations identified in our mock
catalogue are physically dense systems of four or more galaxies with no
interlopers, approximately half are close associations of 2, 3 or 4 galaxies
with one or more interlopers, and the remainder are not physically dense.
Genuine compact groups are preferentially brighter and more isolated than those
with interlopers; by increasing the required minimum surface brightness of a
group from the canonical value of 26mags/arcsec^2 to 22mags/arcsec^2, we can
increase the proportion of genuinely compact systems identified with no
interlopers from 29% to 75%. Of the genuine compact groups identified, more
than half consist of a single dark matter halo with all the member galaxies
deeply embedded within it. In some cases, there are other galaxies which share
the same halo (typically with mass ~ 10^13 h^{-1} M_\odot) but which are not
identified as being members of the compact group. This implies that compact
groups are associated with group environments, some or all members of which are
in the compact group. For those compact groups where all galaxies are in the
same halo, the three-dimensional velocity dispersion of the compact group
correlates broadly with the virial velocity of the dark matter halo. However,
the scale-size of the group - and hence the fraction of the halo mass which the
group samples - is completely uncorrelated with the properties of the dark
matter halo. This means that masses derived under the simple assumption of
virial equilibrium using the observed velocity dispersions and sizes of compact
groups give incorrect estimates of the true mass of the underlying dark matter.


title:
Universal Equation of States are Derived from the Isothermal
  Relationships of Elastic Solids

abstract:
  Universal P-V-T equations of states are derived from the original isothermal
expressions of Birch-Murnaghan and the Vinet EoSs by using absolute reference
frame and incorporating the temperature dependence of the parameters. The
equations are tested against the experiments of perovskite [MgSiO3] and
periclase [MgO]. The determined parameters of the EoSs are valid throughout the
entire pressure and temperature ranges, which cover 0-142 GPa and 293-3000 K
and 0-109 GPa and 293-2199 K for periclase and perovskite respectively. The
root-mean-square (RMS) misfits of the universal Birch-Murnaghan EoS are 0.73
and 0.33 GPa and the misfit of the Vinet EoS are 0.74 and 0.32 GPa for
perovskite and periclase respectively.


title: Pairs of Noncrossing Free Dyck Paths and Noncrossing Partitions

abstract:
  Using the bijection between partitions and vacillating tableaux, we establish
a correspondence between pairs of noncrossing free Dyck paths of length $2n$
and noncrossing partitions of $[2n+1]$ with $n+1$ blocks. In terms of the
number of up steps at odd positions, we find a characterization of Dyck paths
constructed from pairs of noncrossing free Dyck paths by using the Labelle
merging algorithm.


title: A new class of plane symmetric solution

abstract:
  A new class of static plane symmetric solution of Einstein field equation
generated by a perfect fluid source is put forward. A special family of this
new solution is investigated in detail. The constraints on the parameters by
different energy conditions are studied. The classical stability of this
solution is discussed. The junction conditions matching to Minkowski metric and
Taub metric are analyzed respectively.


title: Is there hydrodynamic flow at RHIC ?

abstract:
  It is argued that the observation of anisotropic azimuthal distribution of
final state particles alone is insufficient to show whether the formed matter
at RHIC behaves like hydrodynamic flow. Examining the intrinsic interaction (or
correlation) of the formed matter should provide more definite judgement. To
the end, a spatial-dependent azimuthal multiplicity-correlation pattern is
suggested. It shows clearly in the pattern that there are two kinds of
interactions at the early stage of Au + Au collisions at $\sqnn=200$ GeV
generated by RQMD with hadron re-scattering and AMPT with string melting. This
is out of the expectation from the elliptic flow driven by anisotropic
expansion.


title:
The Conjecture of Nowicki on Weitzenboeck derivations of polynomial
  algebras

abstract:
  The Weitzenboeck theorem states that the algebra of constants of a linear
locally nilpotent derivation of the polynomial algebra K[Z]=K[z_1,...,z_m] in m
variables over a field K of characteristic 0 is finitely generated. If m=2n and
the Jordan normal form of the derivation consists of Jordan cells of size 2
only, we may assume that K[Z]=K[X,Y] and the derivation sends y_i to x_i and
x_i to 0, i=1,...,n. Nowicki conjectured that the algebra of constants of this
derivation is generated by x_1,...,x_n and x_iy_j-x_jy_i, i<j. Recently this
conjecture was confirmed in the Ph.D. thesis of Khoury, and also by Derksen. In
this paper we give an elementary proof of the conjecture of Nowicki. Then we
find a very simple system of defining relations of the algebra of constants
which corresponds to the reduced Groebner basis of the related ideal with
respect to a suitable admissible order, and present an explicit basis of the
algebra of constants as a vector space.


title: The Aleph-zero or zero dichotomy

abstract:
  This paper proves the existence of a dichotomy which being formally derived
from the topological successiveness of w-order leads to the same absurdity of
Zeno's Dichotomy II. It also derives a contradictory result from the first
Zeno's Dichotomy.


title: Recursion and w-order

abstract: This paper has been withdrawn by the author due to an error.


title: Wigner Oscillators, Twisted Hopf Algebras and Second Quantization

abstract:
  By correctly identifying the role of central extension in the centrally
extended Heisenberg algebra h, we show that it is indeed possible to construct
a Hopf algebraic structure on the corresponding enveloping algebra U(h) and
eventually deform it through Drinfeld twist. This Hopf algebraic structure and
its deformed version U^F(h) are shown to be induced from a more fundamental
Hopf algebra obtained from the Schroedinger field/oscillator algebra and its
deformed version, provided that the fields/oscillators are regarded as
odd-elements of the super-algebra osp(1|2n). We also discuss the possible
implications in the context of quantum statistics.


title: Margin-adaptive model selection in statistical learning

abstract:
  A classical condition for fast learning rates is the margin condition, first
introduced by Mammen and Tsybakov. We tackle in this paper the problem of
adaptivity to this condition in the context of model selection, in a general
learning framework. Actually, we consider a weaker version of this condition
that allows one to take into account that learning within a small model can be
much easier than within a large one. Requiring this "strong margin adaptivity"
makes the model selection problem more challenging. We first prove, in a
general framework, that some penalization procedures (including local
Rademacher complexities) exhibit this adaptivity when the models are nested.
Contrary to previous results, this holds with penalties that only depend on the
data. Our second main result is that strong margin adaptivity is not always
possible when the models are not nested: for every model selection procedure
(even a randomized one), there is a problem for which it does not demonstrate
strong margin adaptivity.


title: Superswapping

abstract:
  Supertask theory is used here to prove a contradictory result which involves
the consistency of w-order and the Axiom of Infinity.


title: A disturbing supertask

abstract:
  This paper examines the consistency of w-order by means of a supertask that
functions as a supertrap for the assumed existence of w-ordered collections,
which are simultaneously complete (as is required by the Actual infinity) and
uncompletable (because no last element completes them).


title:
Secret Key Agreement by Soft-decision of Signals in Gaussian Maurer's
  Model

abstract:
  We consider the problem of secret key agreement in Gaussian Maurer's Model.
In Gaussian Maurer's model, legitimate receivers, Alice and Bob, and a
wire-tapper, Eve, receive signals randomly generated by a satellite through
three independent memoryless Gaussian channels respectively. Then Alice and Bob
generate a common secret key from their received signals. In this model, we
propose a protocol for generating a common secret key by using the result of
soft-decision of Alice and Bob's received signals. Then, we calculate a lower
bound on the secret key rate in our proposed protocol. As a result of
comparison with the protocol that only uses hard-decision, we found that the
higher rate is obtained by using our protocol.


title: I=2 Two-Pion Wave Function and Scattering Phase Shift

abstract:
  We calculate a two-pion wave function for the I=2 $S$-wave two-pion system
with a finite scattering momentum and estimate the interaction range between
two pions, which allows us to examine the validity of a necessary condition for
the finite size formula presented by Rummukainen and Gottlieb. We work in the
quenched approximation employing the plaquette gauge action for gluons and the
improved Wilson action for quarks at $1/a=1.63 {\rm GeV}$ on $32^3\times 120$
lattice. The quark masses are chosen to give $m_\pi = 0.420$, 0.488 and $0.587
{\rm GeV}$. We find that the energy dependence of the interaction range is
small and the necessary condition is satisfied for our range of the quark mass
and the scattering momentum, $k \le 0.16 {\rm GeV}$. We also find that the
scattering phase shift can be obtained with a smaller statistical error from
the two-pion wave function than from the two-pion time correlator.


title:
Electronic control of extraordinary terahertz transmission through
  subwavelength metal hole arrays

abstract:
  We describe the electronic control of extraordinary terahertz transmission
through subwavelength metal hole arrays fabricated on doped semiconductor
substrates. The hybrid metal-semiconductor forms a Schottky diode structure,
where the active depletion region modifies the substrate conductivity in
real-time by applying an external voltage bias. This enables effective control
of the resonance enhanced terahertz transmission. Our proof of principle device
achieves an intensity modulation depth of 52% by changing the voltage bias
between 0 and 16 volts. Further optimization may result in improvement of
device performance and practical applications. This approach can be also
translated to the other optical frequency ranges.


title:
Proposal for direct measurement of concurrence via visibility in a
  cavity QED system

abstract:
  An experimental scheme is proposed that allows direct measurement of the
concurrence of a two-qubit cavity system. It is based on the cavity-QED
technology using atoms as flying qubits and relies on the identity of the
two-particle visibility of the atomic probability with the concurrence of the
cavity system. The scheme works for any arbitrary pure initial state of the
two-qubit cavity system.


title:
Polarisation selective magnetic vortex dynamics and core reversal in
  rotating magnetic fields

abstract:
  A magnetic vortex occurs as an equilibrium configuration in thin
ferromagnetic platelets of micron and sub-micron size and is characterised by
an in-plane curling magnetisation. At the centre, a magnetic singularity is
avoided by an out-of-plane magnetisation core. This core has a gyrotropic
excitation mode, which corresponds to a circular motion of the vortex around
its equilibrium position, where the rotation sense is determined by the
direction of the vortex core magnetisation, its polarisation. Unlike linear
fields or spin polarised currents, which excite both polarisation states, an
in-plane rotating field can selectively excite one of the polarisation states.
Here we report the observation of vortex dynamics in response to rotating
magnetic fields, imaged with time-resolved scanning X-ray microscopy. We
demonstrate that the rotating field only excites the gyrotropic mode if the
rotation sense of the field coincides with the vortex gyration sense and that
such a field can selectively reverse the vortex polarisation.


title: Superconducting properties and Hall Effect of epitaxial NbN thin films

abstract:
  We have measured the magnetotransport properties and Hall effect of a series
of epitaxial NbN films grown on (100) oriented single crystalline MgO substrate
under different conditions using reactive magnetron sputtering. Hall effect
measurements reveal that the carrier density in NbN thin films is sensitive to
the growth condition. The carrier density increases by a factor of 3 between
the film with highest normal state resistivity (rho_n~3.83micro-Ohm-m) and
lowest transition temperature (Tc~9.99K) and the film with lowest normal state
resistivity (rho_n~0.94micro-Ohm-m) and highest transition temperature
(Tc~16.11K) while the mobility of carriers does not change significantly except
for the most resistive films. Our results show that the Tc of NbN is governed
primarily by the carrier density rather than disorder scattering. By varying
the carrier concentration during growth we can vary the effective disorder
(kF_l) from the moderately clean limit to the dirty limit which makes this
system ideal to study the interplay of carrier density and disorder on the
superconducting properties of an s-wave superconductor.


title:
Approach of the constitutive material behaviour of textile composites
  through simulation

abstract:
  A complete approach for the determination of the complex constitutive
behaviour of textile composites through finite element simulation is presented
in this paper. In this work, simulations of different loading cases are carried
out on small samples of textile composites, taking into account all individual
fibers of the fabric and interactions taking place between them. The most
delicate issue is related to the modelling of contact-friction interactions
between fibers,and the solution of the nonlinear problem that follows up by the
means of robust algorithms. The efficiency of these algorithms, and the
increase of capacities of high performance computing, allow to simulate samples
made of several hundreds of interlocked fibers.


title: How Weyl stumbled across electricity while pursuing mathematical justice

abstract:
  It is argued that Weyl's theory of gravitation and electricity came out of
`mathematical justice': out of the equal rights direction and length. Such
mathematical justice was manifestly at work in the context of discovery, and is
enough (together with a couple of simple and natural operations) to derive all
of source-free electromagnetism. Weyl's repeated references to coordinates and
gauge are taken to express equal treatment of direction and length.


title:
On the $S_n$-equivariant Euler characteristic of moduli spaces of
  hyperelliptic curves

abstract:
  The generating function for $S_n$-equivariant Euler characteristics of moduli
spaces of pointed hyperelliptic curves for any genus g>1 is calculated. This
answer generalizes the known ones for genera 2 and 3 and answers obtained by J.
Bergstrom for any genus and n<8 points.


title:
Potassium ground state scattering parameters and Born-Oppenheimer
  potentials from molecular spectroscopy

abstract:
  We present precision measurements with MHz uncertainty of the energy gap
between asymptotic and well bound levels in the electronic ground state X
$^1\Sigma_{\mathrm{g}}^+$ of the $^{39}$K$_2$ molecule. The molecules are
prepared in a highly collimated particle beam and are interrogated in a
$\Lambda$-type excitation scheme of optical transitions to long range levels
close to the asymptote of the ground state, using the electronically excited
state A $^1\Sigma^+_{\rm u}$ as intermediate one. The transition frequencies
are measured either by comparison with I$_2$ lines or by absolute measurements
using a fs-frequency comb. The determined level energies were used together
with Feshbach resonances from cold collisions of $^{39}$K and $^{40}$K reported
from other authors to fit new ground state potentials. Precise scattering
lengths are determined and tests of the validity of the Born-Oppenheimer
approximation for the description of cold collisions at this level of precision
are performed.


title: An Adaptive-Parity Error-Resilient LZ'77 Compression Algorithm

abstract:
  The paper proposes an improved error-resilient Lempel-Ziv'77 (LZ'77)
algorithm employing an adaptive amount of parity bits for error protection. It
is a modified version of error resilient algorithm LZRS'77, proposed recently,
which uses a constant amount of parity over all of the encoded blocks of data.
The constant amount of parity is bounded by the lowest-redundancy part of the
encoded string, whereas the adaptive parity more efficiently utilizes the
available redundancy of the encoded string, and can be on average much higher.
The proposed algorithm thus provides better error protection of encoded data.
  The performance of both algorithms was measured. The comparison showed a
noticeable improvement by use of adaptive parity. The proposed algorithm is
capable of correcting up to a few times as many errors as the original
algorithm, while the compression performance remains practically unchanged.


title:
A Monte Carlo simulation of the intergalactic absorption and the
  detectability of the Lyman continuum from distant galaxies

abstract:
  We have made a Monte Carlo simulation of the intergalactic absorption in
order to model the Lyman continuum absorption, which is required to estimate
the escape fraction of the Lyman continuum from distant galaxies. To input into
the simulation, we derive an empirical distribution function of the
intergalactic absorbers which reproduces recent observational statistics of the
Lyman $\alpha$ forest, Lyman limit systems (LLSs), and damped Lyman $\alpha$
systems (DLAs) simultaneously. In particular, we assume a common functional
form of the number evolution along the redshift for all types of absorbers. The
Lyman series transmissions in our simulation reproduce the observed redshift
evolution of the transmissions excellently, and the Lyman continuum
transmission also agrees with an observed estimation which is still quite rare
in the literature. The probability distribution of the Lyman $\alpha$ opacity
in our simulation is log-normal with a tail towards a large opacity. This tail
is produced by DLAs. The probability distribution of the Lyman continuum
opacity in our simulation also show a broad tail towards a large opacity. This
tail is produced by LLSs. Because of the rarity of LLSs, we have a chance to
have a clean line of sight in the Lyman continuum even for $z\sim4$ with a
probability of about 20%. Our simulation expects a good correlation between the
Lyman continuum opacity and the Lyman $\alpha$ opacity, which may be useful to
estimate the former from the latter for an individual line of sight.


title:
A finite element approach of the behaviour of woven materials at
  microscopic scale

abstract:
  A finite element simulation of the mechanical behaviour of woven textile
materials at the scale of individual fibers is proposed in this paper. The aim
of the simulation is to understand and identify phenomena involved at different
scales in such materials. The approach considers small patches of woven textile
materials as collections of fibers. Fibers are modelled by 3D beam elements,
and contact-friction interactions are considered between them. An original
method for the detection of contacts, and the use of efficient algorithms to
solve the nonlinearities of the problem, allow to handle patches made of few
hundreds of fibers. The computation of the unknown initial configuration of the
woven structure is carried out by simulating the weaving process. Various
loading cases can then be applied to the studied patches to identify their
mechanical characteristics. To approach the mesoscopic behaviour of yarns, 3D
strains are calculated at the scale of yarns, as post-processing. These strains
display strong inhomogeinities, which raises the question of using continuous
models at the scale of yarns.


title:
Towards quantum optics and entanglement with electron spin ensembles in
  semiconductors

abstract:
  We discuss a technique and a material system that enable the controlled
realization of quantum entanglement between spin-wave modes of electron
ensembles in two spatially separated pieces of semiconductor material. The
approach uses electron ensembles in GaAs quantum wells that are located inside
optical waveguides. Bringing the electron ensembles in a quantum Hall state
gives selection rules for optical transitions across the gap that can
selectively address the two electron spin states. Long-lived superpositions of
these electron spin states can then be controlled with a pair of optical fields
that form a resonant Raman system. Entangled states of spin-wave modes are
prepared by applying quantum-optical measurement techniques to optical signal
pulses that result from Raman transitions in the electron ensembles.


title: A peculiarity of metal-poor stars with planets ?

abstract:
  Stars with planets at intermediate metallicities ([-0.7,-0.2] dex) exhibit
properties that differ from the general field stars. Thirteen stars with
planets reported in this metallicity range belong to the thick disc, while only
one planet have been detected among stars of the thin disc. Although this
statistics is weak, it contradicts the known correlation between the presence
of planet and metallicity. We relate this finding to the specific property of
the thin disc in this metallicity range, where stars are shown to rotate around
the Galaxy faster than the Sun. Their orbital parameters are conveniently
explained if they are contaminants coming from the outer Galactic disc, as a
result of radial mixing. This must be considered together with the fact that
metal-rich stars ([Fe/H]>+0.1 dex) found in the solar neighbourhood, which are
the hosts of most of the detected planets, are suspected of being wanderers
from the inner Galactic disc. It is then questionned why stars that originate
in the inner and outer thin disc show respectively the highest and lowest rate
of detected planets. It is suggested that the presence of giant planets might
be primarily a function of a parameter linked to galactocentric radius, but not
metallicity. Combined with the existing radial metallicity gradient, then
radial mixing explains the correlation at high metallicity observed locally,
but also the peculiarity found at low metallicity, which cannot be accounted
for by a simple correlation between metallicity and planet probability.


title:
Broadband squeezed light from phase-locked single-mode sub-Poissonian
  lasers

abstract:
  We consider sub-Poissonian single-mode laser with external synchronization
and analyze its applicability to the problems of quantum information. Using
Heisenberg-Langevin theory we calculate the quadrature variances of the field
emitted by this laser. It is shown that such systems can demonstrate strong
quadrature squeezing. Taking into account that the emitted field is temporally
multi-mode the application of such sources to multichannel quantum
teleportation and dense coding protocols is discussed.


title:
A construction of spherical designs from finite graphs with the theory
  of crystal lattice

abstract:
  We want to introduce a construction of spherical designs from finite graphs
with the theory of crystal lattice. We start from a finite graph, and we
consider standard realization of the crystal lattices as the maximal Abelian
covering of the graph. Then, we take the set of vectors which form the crystal
lattice. If every vector has the same norm, then we can consider a finite set
on Euclidean sphere, and then we get a spherical design.
  In this paper, we observe the results by numerical calculations. We tried
constructing vectors from various finite graphs, strongly regular graphs,
distance regular graphs, and so on. We also introduce some facts and
conjectures.


title:
Upperbound on Squark Masses in Gauge-Mediation Model with Light
  Gravitino

abstract:
  We examine stabilities of our supersymmetry-breaking false vacuum in a
low-energy direct gauge mediation model of SUSY breaking. The stability
required in the high-temperature early universe leads to upperbounds on masses
of squarks and gluino as m_\tilde{q} \lesssim 1 TeV and m_\tilde{g} \lesssim 1
TeV for the light gravitino of mass m_{3/2} \lesssim 16 eV.


title:
Demystifying Double Robustness: A Comparison of Alternative Strategies
  for Estimating a Population Mean from Incomplete Data

abstract:
  When outcomes are missing for reasons beyond an investigator's control, there
are two different ways to adjust a parameter estimate for covariates that may
be related both to the outcome and to missingness. One approach is to model the
relationships between the covariates and the outcome and use those
relationships to predict the missing values. Another is to model the
probabilities of missingness given the covariates and incorporate them into a
weighted or stratified estimate. Doubly robust (DR) procedures apply both types
of model simultaneously and produce a consistent estimate of the parameter if
either of the two models has been correctly specified. In this article, we show
that DR estimates can be constructed in many ways. We compare the performance
of various DR and non-DR estimates of a population mean in a simulated example
where both models are incorrect but neither is grossly misspecified. Methods
that use inverse-probabilities as weights, whether they are DR or not, are
sensitive to misspecification of the propensity model when some estimated
propensities are small. Many DR methods perform better than simple
inverse-probability weighting. None of the DR methods we tried, however,
improved upon the performance of simple regression-based prediction of the
missing values. This study does not represent every missing-data problem that
will arise in practice. But it does demonstrate that, in at least some
settings, two wrong models are not better than one.