title: Hopf Bifurcations in a Watt Governor With a Spring

abstract:
  This paper pursues the study carried out by the authors in "Stability and
Hopf bifurcation in a hexagonal governor system", focusing on the codimension
one Hopf bifurcations in the hexagonal Watt governor differential system. Here
are studied the codimension two, three and four Hopf bifurcations and the
pertinent Lyapunov stability coefficients and bifurcation diagrams, ilustrating
the number, types and positions of bifurcating small amplitude periodic orbits,
are determined. As a consequence it is found an open region in the parameter
space where two attracting periodic orbits coexist with an attracting
equilibrium point.


title: Poisson geometry and first integrals of geostrophic equations

abstract:
  We describe first integrals of geostrophic equations, which are similar to
the enstrophy invariants of the Euler equation for an ideal incompressible
fluid. We explain the geometry behind this similarity, give several equivalent
definitions of the Poisson structure on the space of smooth densities on a
symplectic manifold, and show how it can be obtained via the Hamiltonian
reduction from a symplectic structure on the diffeomorphism group.


title:
Imbalanced d-wave superfluids in the BCS-BEC crossover regime at finite
  temperatures

abstract:
  Singlet pairing in a Fermi superfluid is frustrated when the amounts of
fermions of each pairing partner are unequal. The resulting `imbalanced
superfluid' has been realized experimentally for ultracold atomic gases with
s-wave interactions. Inspired by high-temperature superconductivity, we
investigate the case of d-wave interactions, and find marked differences from
the s-wave superfluid. Whereas s-wave imbalanced Fermi gases tend to phase
separate in real space, in a balanced condensate and an imbalanced normal halo,
we show that the d-wave gas can phase separate in reciprocal space so that
imbalance and superfluidity can coexist spatially. We show that the mechanism
explaining this property is the creation of polarized excitations in the nodes
of the gap. The Sarma mechanism, present only at nonzero temperatures for the
s-wave case, is still applicable in the temperature zero limit for the d-wave
case. As a result, the d-wave BCS superfluid is more robust with respect to
imbalance, and a region of the phase diagram can be identified where the s-wave
BCS superfluidity is suppressed whereas the d-wave superfluidity is not. When
these results are extended into the BEC limit of strongly bound molecules, the
symmetry of the order parameter matters less. The effects of fluctuations
beyond mean field is taken into account in the calculation of the structure
factor and the critical temperature. The poles of the structure factor
(corresponding to bound molecular states) are less damped in the d-wave case as
compared to s-wave. On the BCS side of the unitarity limit, the critical
temperature follows the temperature corresponding to the pair binding energy
and as such will also be more robust against imbalance. Possible routes for the
experimental observation of the d-wave superfluidity have been discussed.


title: Hong-Ou-Mandel dip using photon pairs from a PPLN waveguide

abstract:
  We experimentally observed a Hong-Ou-Mandle dip with photon pairs generated
in a periodically poled reverse-proton-exchange lithium niobate waveguide with
an integrated mode demultiplexer at a wavelength of 1.5 um. The visibility of
the dip in the experiment was 80% without subtraction of any noise terms at a
peak pump power of 4.4 mW. The new technology developed in the experiment can
find various applications in the research field of linear optics quantum
computation in fiber or quantum optical coherence tomography with near infrared
photon pairs.


title: Mechanical feedback in the high-frequency limit

abstract:
  We investigate strong mechanical feedback for the single-electron tunneling
device coupled to an underdamped harmonic oscillator in the high-frequency
case, when the mechanical energy of the oscillator exceeds the tunnel rate, and
for weak coupling. In the strong feedback regime, the mechanical oscillations
oscillated by the telegraph signal from the SET in their turn modify the
electric current. In contrast to the earlier results for the low frequencies,
the current noise in not enhanced above the Poisson value.


title: Classical and Quantum Spins in Curved Spacetimes

abstract:
  A comparative analysis of the Mathisson-Papapetrou and Pomeransky-Khriplovich
equations is presented. Motion of spinning particles and their spins in
gravitational fields and noninertial frames is considered. The angular velocity
of spin precession defined by the Pomeransky-Khriplovich equations depends on
the choice of the tetrad. The connection of such a dependence with the Thomas
precession is established. General properties of spin interactions with
gravitational fields are discussed. It is shown that dynamics of classical and
quantum spins in curved spacetimes is identical. A manifestation of the
equivalence principle in an evolution of the helicity is analyzed.


title: On duality of the noncommutative Maxwell-Chern-Simons theory

abstract:
  We study the possibility of establishing the dual equivalence between the
noncommutative Maxwell-Chern-Simons theory and the noncommutative self-dual
theory. It turns to be that whereas in the commutative case the
Maxwell-Chern-Simons theory can be mapped into the sum of the self-dual theory
and the Chern-Simons theory, in the noncommutative case such a mapping is
possible only for the theory with the modified Maxwell term.


title:
Testing high-energy factorization beyond the next-to-leading-logarithmic
  accuracy

abstract:
  By taking the high-energy limit of the two-loop and the three-loop four-point
amplitudes in the maximally supersymmetric N=4 Yang-Mill theory (MSYM), we test
the validity of the loop expansion of the high-energy amplitude, beyond the
next-to-leading-logarithmic (NLL) accuracy. We compute the three-loop Regge
trajectory, and the two-loop and three-loop coefficient functions. These
quantities are relevant for the BFKL evolution beyond NLL, as well as building
MSYM two-loop and three-loop amplitudes with many legs in the high-energy
limit, which in turn may be used as a powerful check of the evaluation of the
corresponding exact amplitudes.


title: Holmberg Ix: The Nearest Young Galaxy

abstract:
  Deep images taken with the Wide Field Channel of the Advanced Camera for
Surveys on board the Hubble Space Telescope provide the basis for study the
resolved stellar population of the M81 companion dwarf irregular galaxy
Holmberg IX. Based on color-magnitude diagrams the stellar population toward
Holmberg IX contains numerous stars with ages of <~200 Myr as well as older red
giant stars. By charting the spatial distribution of the red giant stars and
considering their inferred metallicities, we concluded that most of these older
stars are associated with M81 or its tidal debris. At least 20% of the stellar
mass in Holmberg IX was produced in the last ~200 Myr, giving it the youngest
stellar populations if any nearby galaxy. The location of Holmberg IX, its high
gas content, and its youthful stellar population suggests that it is a tidal
dwarf galaxy, perhaps formed during the last close passage of M82 around M81.


title: On composite systems of dilute and dense couplings

abstract:
  Composite systems, where couplings are of two types, a combination of strong
dilute and weak dense couplings of Ising spins, are examined through the
replica method. The dilute and dense parts are considered to have independent
canonical disordered or uniform bond distributions; mixing the models by
variation of a parameter $\gamma$ alongside inverse temperature $\beta$ we
analyse the respective thermodynamic solutions. We describe the variation in
high temperature transitions as mixing occurs; in the vicinity of these
transitions we exactly analyse the competing effects of the dense and sparse
models. By using the replica symmetric ansatz and population dynamics we
described the low temperature behaviour of mixed systems.


title: Relations between the modified Chaplygin gas and a scalar field

abstract:
  In this work the modified Chaplygin gas is related to a cosmological scalar
field. Analytical results, more general than the solutions previously shown in
the literature, are presented for the case when the curvature is absent, and
one entirely new particular result is shown for a case where there is
curvature. Also, it is emphasized here that one interesting feature of the
scalar field associated to the modified Chaplygin gas is the possible presence
of two minima in its potential. Finally, it is argued that the scalar field
representation of the Chaplygin gas can be another useful tool in the study of
the evolution of perturbations and, as an example of this, a new analytical
result for the density contrast is presented.


title:
Stationary condition in a perturbative approach for mass varying
  neutrinos

abstract:
  A perturbative approach for arbitrary choices of the equation of state of the
universe is introduced in order to treat scenarios for mass varying neutrinos
(MaVaN's) coupled to the dark sector. The generalized criterion for the
applicability of such an approach is expressed through a constraint on the
coefficient of the linear perturbation on the dark sector scalar field. This
coefficient depends on the ratio between the variation of the neutrino energy
and the scalar field potential. Upon certain conditions, the usual {\em
stationary condition} found in the context of MaVaN models together with the
perturbative contribution can be employed to predict the dynamical evolution of
the neutrino mass. Our results clearly indicate that the positiveness of the
squared speed of sound of the coupled fluid and the model stability are not
conditioned by the {\em stationary condition}.


title: A Study On Distributed Model Predictive Consensus

abstract:
  We investigate convergence properties of a proposed distributed model
predictive control (DMPC) scheme, where agents negotiate to compute an optimal
consensus point using an incremental subgradient method based on primal
decomposition as described in Johansson et al. [2006, 2007]. The objective of
the distributed control strategy is to agree upon and achieve an optimal common
output value for a group of agents in the presence of constraints on the agent
dynamics using local predictive controllers. Stability analysis using a
receding horizon implementation of the distributed optimal consensus scheme is
performed. Conditions are given under which convergence can be obtained even if
the negotiations do not reach full consensus.


title:
On the cohomology of certain non-compact Shimura varieties (with an
  appendix by Robert Kottwitz)

abstract:
  The goal of this paper is to calculate the trace of the composition of a
Hecke correspondence and a (high enough) power of the Frobenius at a good place
on the intersection cohomology of the Satake-Baily-Borel compactification of
certain Shimura varieties, to stabilize the result for Shimura varieties
associated to unitary groups over $\mathbb{Q}$ and to give applications of this
calculations using base change from these unitary groups to $GL_n$.
  -----
  Le but de ce texte est de calculer la trace d'une correspondance de Hecke
composee avec une puissance (assez grande) du Frobenius en une bonne place sur
la cohomologie d'intersection de la compactification de Satake-Baily-Borel de
certaines varietes de Shimura, de stabiliser le resultat obtenu pour les
varietes de Shimura associees aux groupes unitaires sur $\mathbb{Q}$, et de
donner des applications de ces calculs en utilisant le changement de base de
ces groupes unitaires a $GL_n$.


title:
Analytic calculations of the spectra of ultra-high energy cosmic ray
  nuclei. I. The case of CMB radiation

abstract:
  We present a systematic study of different methods for the analytic
calculation of ultra-high energy nuclei diffuse spectra. Nuclei propagating in
the intergalactic space are photo-disintegrated and decrease their Lorentz
factor due to the interaction with cosmic microwave background and
extragalactic background light. We calculate the evolution trajectories in the
backward time, that describe how atomic mass number $A$ and Lorentz factor
$\Gamma$ change with redshift $z$. Three methods of spectra calculations are
investigated and compared: {\it (i)} trajectory method, {\it(ii)} kinetic
equation combined with trajectory calculations and {\it (iii)} coupled kinetic
equations. We believe that these three methods exhaust at least the principal
possibilities for any analytic solution of the problem. In the most
straightforward method {\it(i)} only trajectory calculations are used to
connect the observed nuclei flux with the production rate of primary
(accelerated) nuclei $A_0$. In the second method {\it (ii)} the flux (space
density) of primary nuclei, and secondary nuclei and protons are calculated
with the help of kinetic equation and trajectories are used only to determine
the generation rates of these nuclei. The third method {\it (iii)} consists in
solving the complete set of coupled kinetic equations, written starting with
primary nuclei $A_0$, then for $A_0-1$ etc down to the $A$ of interest. The
solution of the preceding equation gives the generation rate for the one which
follows. An important element of the calculations for all methods is the
systematic use of Lorentz factor instead of energy. We consider here the
interaction of nuclei only with the cosmic microwave background, this case is
particularly suitable for understanding the physical results.


title: Geometrical formulation of classical electromagnetism

abstract:
  A general affine connection has enough degrees of freedom to describe the
classical gravitational and electromagnetic fields in the metric-affine
formulation of gravity. The gravitational field is represented in the
Lagrangian by the symmetric part of the Ricci tensor, while the classical
electromagnetic field is represented geometrically by the tensor of homothetic
curvature. We introduce matter as the four-velocity field subject to the
kinematical constraint in which the Lagrange multiplier represents the energy
density. A coupling between the four-velocity and the trace of the nonmetricity
tensor represents the electric charge density. We show that the simplest
metric-affine Lagrangian that depends on the Ricci tensor and the tensor of
homothetic curvature generates the Einstein-Maxwell field equations, while the
Bianchi identity gives the Lorentz equation of motion. If the four-velocity
couples to the torsion vector, the Einstein equations are modified by a term
that is significant at the Planck scale and may prevent the formation of
spacetime singularities.


title:
First-order spatial coherence of excitons in planar nanostructures: a
  k-filtering effect

abstract:
  We propose and analyze a k-filtering effect which gives rise to the drastic
difference between the actual spatial coherence length of quasi-two-dimensional
(quasi-2D) excitons or microcavity (MC) polaritons in planar nanostructures and
that inferred from far-field optical measurements. The effect originates from
the conservation of in-plane wavevector k in the optical decay of the particles
in outgoing bulk photons. The k-filtering effect explains the large coherence
lengths recently observed for indirect excitons in coupled quantum wells (QWs),
but is less pronounced for MC polaritons at low temperatures, T<10K.


title:
Heat conduction and Fourier's law in a class of many particle dispersing
  billiards

abstract:
  We consider the motion of many confined billiard balls in interaction and
discuss their transport and chaotic properties. In spite of the absence of mass
transport, due to confinement, energy transport can take place through binary
collisions between neighbouring particles. We explore the conditions under
which relaxation to local equilibrium occurs on time scales much shorter than
that of binary collisions, which characterize the transport of energy, and
subsequent relaxation to local thermal equilibrium. Starting from the
pseudo-Liouville equation for the time evolution of phase-space distributions,
we derive a master equation which governs the energy exchange between the
system constituents. We thus obtain analytical results relating the transport
coefficient of thermal conductivity to the frequency of collision events and
compute these quantities. We also provide estimates of the Lyapunov exponents
and Kolmogorov-Sinai entropy under the assumption of scale separation. The
validity of our results is confirmed by extensive numerical studies.


title:
Effects of elastic heterogeneity and anisotropy on the morphology of
  self-assembled epitaxial quantum dots

abstract:
  Epitaxial self-assembled quantum dots (SAQDs) are of both technological and
fundamental interest, but their reliable manufacture still presents a technical
challenge. To better understand the formation, morphology and ordering of
epitaxial self-assembled quantum dots (SAQDs), it is essential to have an
accurate model that can aid further experiments and predict the trends in SAQD
formation. SAQDs form because of the destabilizing effect of elastic mismatch
strain, but most analytic models and some numerical models of SAQD formation
either assume an elastically homogeneous anisotropic film-substrate system or
assume an elastically heterogeneous isotropic system. In this work, we perform
the full film-substrate elastic calculation. Then we incorporate the elasticity
calculation into a stochastic linear growth model. We find that using
homogeneous elasticity can cause errors in the elastic energy density as large
as 26%, and for typical modeling parameters lead to errors of about 11% in the
estimated value of average dot spacing. We also quantify the effect of elastic
heterogeneity on the order estimates of SAQDs and confirm previous finding on
the possibility of order enhancement by growing a film near the critical film
height.


title:
Experimental evidence for a surface distribution of two-level systems in
  superconducting lithographed microwave resonators

abstract:
  We present measurements of the temperature-dependent frequency shift of five
niobium superconducting coplanar waveguide microresonators with center strip
widths ranging from 3 $\mu$m to 50 $\mu$m, taken at temperatures in the range
100-800 mK, far below the 9.2 K transition temperature of niobium. These data
agree well with the two-level system (TLS) theory. Fits to this theory provide
information on the number of TLS that interact with each resonator geometry.
The geometrical scaling indicates a surface distribution of TLS, and the data
are consistent with a TLS surface layer thickness of order a few nm, as might
be expected for a native oxide layer.


title: Topometric spaces and perturbations of metric structures

abstract:
  We develop the general theory of \emph{topometric spaces}, i.e., topological
spaces equipped with a well-behaved lower semi-continuous metric function.
Spaces of global and local types in continuous logic are the motivating
examples for the study of such spaces. In particular, we develop a theory of
Cantor-Bendixson analysis of topometric spaces, which can serve as a basis for
the study of local stability (extending the \textit{ad hoc} development from
\cite{BenYaacov-Usvyatsov:CFO}), as well as of global $\aleph_0$-stability. We
conclude with a study of perturbation systems (see
\cite{BenYaacov:Perturbations}) in the formalism of topometric spaces. In
particular, we show how the abstract development applies to
$\aleph_0$-stability up to perturbation.


title:
Renewal-type Limit Theorem for Continued Fractions with Even Partial
  Quotients

abstract:
  We prove the existence of the limiting distribution for the sequence of
denominators generated by continued fraction expansions with even partial
quotients, which were introduced by F. Schweiger and studied also by C.
Kraaikamp and A. Lopes. Our main result is proven following the strategy used
by Ya. Sinai and C. Ulcigrai in their proof of a similar renewal-type theorem
for Euclidean continued fraction expansions and the Gauss map. The main steps
in our proof are the construction of a natural extension of a Gauss-like map
and the proof of mixing of a related special flow.


title:
Modified Holder Exponents Approach to Prediction of the USA Stock Market
  Critical Points and Crashes

abstract:
  The paper is devoted to elaboration of a novel specific indicator based on
the modified Holder exponents. This indicator has been used for forecasting
critical points of financial time series and crashes of the USA stock market.
The proposed approach is based on the hypothesis, which claims that before
market critical points occur the dynamics of financial time series radically
changes, namely time series become smoother. The approach has been tested on
the stylized data and real USA stock market data. It has been shown that it is
possible to forecast such critical points of financial time series as large
upward and downward movements and trend changes. On this basis a new trading
strategy has been elaborated and tested.


title:
Time-Resolved Photometry of the Optical Counterpart of Swift
  J2319.4+2619

abstract:
  Time-resolved CCD photometry is presented of the V~17 optical counterpart of
the newly-discovered, hard-X-ray-emitting polar Swift J2619.4+2619. A total of
~20 hr of data obtained over five nights in various bandpasses (B, V, R, and I)
reveals a strong quasi-sinusoidal modulation in the light curve at a
best-fitting period of 0.1254 d (3.01 hr), which we associate with the orbital
period of the system (one-day aliases of this period at 0.1114 d and 0.1435 d
are considered, but appear to be ruled out by our analysis). The amplitude of
the modulation increases with wavelength from ~0.8 mag in B to ~1.1 mag in R
and I. The increase in amplitude with wavelength is typical of polar systems
where the modulated radiation comes from cyclotron emission. The combination of
the relatively long orbital period and the emission of hard X-rays suggest that
Swift J2619.4+2619 may be a good candidate for an asynchronous polar system.


title:
The XMM Cluster Survey: Forecasting cosmological and cluster
  scaling-relation parameter constraints

abstract:
  We forecast the constraints on the values of sigma_8, Omega_m, and cluster
scaling relation parameters which we expect to obtain from the XMM Cluster
Survey (XCS). We assume a flat Lambda-CDM Universe and perform a Monte Carlo
Markov Chain analysis of the evolution of the number density of galaxy clusters
that takes into account a detailed simulated selection function. Comparing our
current observed number of clusters shows good agreement with predictions. We
determine the expected degradation of the constraints as a result of
self-calibrating the luminosity-temperature relation (with scatter), including
temperature measurement errors, and relying on photometric methods for the
estimation of galaxy cluster redshifts. We examine the effects of systematic
errors in scaling relation and measurement error assumptions. Using only (T,z)
self-calibration, we expect to measure Omega_m to +-0.03 (and Omega_Lambda to
the same accuracy assuming flatness), and sigma_8 to +-0.05, also constraining
the normalization and slope of the luminosity-temperature relation to +-6 and
+-13 per cent (at 1sigma) respectively in the process. Self-calibration fails
to jointly constrain the scatter and redshift evolution of the
luminosity-temperature relation significantly. Additional archival and/or
follow-up data will improve on this. We do not expect measurement errors or
imperfect knowledge of their distribution to degrade constraints significantly.
Scaling-relation systematics can easily lead to cosmological constraints 2sigma
or more away from the fiducial model. Our treatment is the first exact
treatment to this level of detail, and introduces a new `smoothed ML' estimate
of expected constraints.


title:
The "Carina Flare" Supershell: Probing the Atomic and Molecular ISM in a
  Galactic Chimney

abstract:
  The "Carina Flare" supershell, GSH 287+04-17, is a molecular supershell
originally discovered in 12CO(J=1-0) with the NANTEN 4m telescope. We present
the first study of the shell's atomic ISM, using HI 21 cm line data from the
Parkes 64m telescope Southern Galactic Plane Survey. The data reveal a gently
expanding, ~ 230 x 360 pc HI supershell that shows strong evidence of Galactic
Plane blowout, with a break in its main body at z ~ 280 pc and a capped
high-latitude extension reaching z ~ 450 pc. The molecular clouds form
co-moving parts of the atomic shell, and the morphology of the two phases
reflects the supershell's influence on the structure of the ISM. We also report
the first discovery of an ionised component of the supershell, in the form of
delicate, streamer-like filaments aligned with the proposed direction of
blowout. The distance estimate to the shell is re-examined, and we find strong
evidence to support the original suggestion that it is located in the Carina
Arm at a distance of 2.6 +- 0.4 kpc. Associated HI and H2 masses are estimated
as M(HI) ~ 7 +- 3 x 10^5 Msol and M(H2) ~ 2.0 +- 0.6 x 10^5 Msol, and the
kinetic energy of the expanding shell as E ~ 1 x 10^51 erg. We examine the
results of analytical and numerical models to estimate a required formation
energy of several 10^51 to ~ 10^52 erg, and an age of ~ 10^7 yr. This age is
compatible with molecular cloud formation time-scales, and we briefly consider
the viability of a supershell-triggered origin for the molecular component.


title:
Heavy-flavour tagging and the supersymmetry reach of the CERN Large
  Hadron Collider

abstract:
  The branching fraction for the decays of gluinos to third generation quarks
is expected to be enhanced in classes of supersymmetric models where either
third generation squarks are lighter than other squarks, or in mixed-higgsino
dark matter models constructed to be in concordance with the measured density
of cold dark matter. In such scenarios, gluino production events at the CERN
Large Hadron Collider should be rich in top and bottom quark jets. Requiring
b-jets in addition to missing transverse energy should, therefore, enhance the
supersymmetry signal relative to Standard Model backgrounds from V + jet, VV
and QCD backgrounds (V=W, Z). We quantify the increase in the supersymmetry
reach of the LHC from b-tagging in a variety of well-motivated models of
supersymmetry. We also explore ``top-tagging'' at the LHC. We find that while
the efficiency for this turns out to be too low to give an increase in reach
beyond that obtained via b-tagging, top-tagging can indeed provide a
confirmatory signal if gluinos are not too heavy. Finally, we explore the
prospects for detecting the direct production of third generation squarks in
models with an inverted squark mass hierarchy. This is signalled by b-jets +
missing transverse energy events harder than in the Standard Model, but softer
than those from the production of gluinos and heavier squarks. We find that
while these events can be readily separated from SM background (for third
generation squark masses ~300-500 GeV), the contamination from the much heavier
gluinos and squarks remains formidable if these are also accessible.


title: Dark matter dynamics in Galactic center

abstract:
  The evolution of dark matter in central areas of galaxies is considered (the
Milky Way is taken as an example). It is driven by scattering off of dark
matter particles by bulge stars, their absorption by the supermassive black
hole and self-annihilation. This process is described by diffusion equation in
the phase space of energy and angular momentum. The equation was integrated for
several different models of initial dark matter distribution and using various
assumptions about the dynamical factors. It turns out that because the Milky
Way center is rather dynamically old (~5 relaxation times t_r), the difference
in initial conditions almost vanishes. The density attains a nearly universal
profile, and the gamma-ray flux from dark matter annihilation lies in rather
narrow range, which enables more robust determination of the dark matter
parameters. By present time the mass of dark matter inside the black hole
sphere of influence (r<2 pc) has been reduced approximately twice, mostly
because of heating by stars. It is shown that the dynamics of dark matter for
t>t_r is determined mainly by stars outside the sphere of influence.


title:
Brightening of an Accretion Disk Due to Viscous Dissipation of
  Gravitational Waves During the Coalescence of Supermassive Black Holes

abstract:
  Mergers of supermassive black hole binaries release peak power of up to
~10^57 erg/s in gravitational waves (GWs). As the GWs propagate through ambient
gas, they induce shear and a small fraction of their power is dissipated
through viscosity. The dissipated heat appears as electromagnetic (EM)
radiation, providing a prompt EM counterpart to the GW signal. For thin
accretion disks, the GW heating rate exceeds the accretion power at distances
farther than 10^3 Schwarzschild radii, independently of the accretion rate and
viscosity coefficient.


title:
Ground-based CCD astrometry with wide field imagers. II. A star
  catalogue for M67: WFI@2.2m MPG/ESO astrometry, FLAMES@VLT radial velocities

abstract:
  The solar-age open cluster M67 (C0847+120, NGC2682) is a touchstone in
studies of the old Galactic disk. Despite its outstanding role, the census of
cluster membership for M67 at fainter magnitudes and their properties are not
well-established. Using the proprietary and archival ESO data, we have obtained
astrometric, photometric, and radial velocities of stars in a 34'x 33' field
centered on the old open cluster M67. The two-epoch archival observations
separated by 4 years and acquired with the Wide Field Imager at the 2.2m
MPG/ESO telescope have been reduced with our new astrometric techniques, as
described in the first paper of this series. The same observations served to
derive calibrated BVI photometry in M67. Radial velocities were measured using
the archival and new spectroscopic data obtained at VLT. We have determined
relative proper motions and membership probabilities for ~2,400 stars. The
precision of proper motions for optimally exposed stars is ~2 mas/yr, gradually
degrading down to ~5 mas/yr at V= 20. Our relatively precise proper motions at
V>16 are first obtained in this magnitude range for M67. Radial velocities are
measured for 211 stars in the same field. We also present a detailed comparison
with recent theoretical isochrones from several independent groups. For M67
area we provide positions, calibrated BVI photometry, relative proper motions,
membership probabilities, and radial velocities. We demonstrate that the
ground-based CCD mosaic observations just a few years apart are producing
proper motions, allowing a reliable membership determination. We produced a
catalogue that is made electronically available to the astronomical community.


title: The binary fraction in the globular cluster NGC 6397

abstract:
  Using Hubble Space Telescope (HST) observations of the globular cluster
NGC6397, we constrain the cluster's binary fraction. The observations consist
of two fields: the primary science field, a single ACS pointing centered
approximately 5' from the cluster center; and the parallel field, a single
WFPC2 field centered on the cluster center. Using the exquisite photometric
precision of these observations, we determine the binary fraction in these
regions of the cluster by examining stars lying off the main sequence. The
binary fraction is constrained to be 0.012 +/- 0.004 in the ACS field, and to
be 0.051 +/- 0.010 in the WFPC field. N-body simulations by Hurley et al.
(2007) suggest that the binary fraction remains nearly constant beyond the
half-mass radius for the lifetime of the cluster. In the context of these
simulations, our results suggest that NGC 6397 had a primordial binary fraction
of only ~1%.


title: Update on Modular Non-Rigid Calabi-Yau Threefolds

abstract:
  We review some recent results on the modularity of non-rigid Calabi-Yau
threefolds.


title: A new nestedness estimator in community networks

abstract:
  A recent problem in community ecology lies in defining structures behind
matrices of species interactions. The interest in this area is to quantify the
nestedness degree of the matrix after its maximal packing. In this work we
evaluate nestedness using the sum of all distances of the occupied sites to the
vertex of the matrix. We calculate the distance for two artificial matrices
with the same size and occupancy: a random matrix and a perfect nested one.
Using these two benchmarks we develop a nestedness estimator. The estimator is
applied to a set of 23 real networks of insect-plant interactions.


title: Derived Functors Related to Wall Crossing

abstract:
  The setting is the representation theory of a simply connected, semisimple
algebraic group over a field of positive characteristic. There is a natural
transformation from the wall-crossing functor to the identity functor. The
kernel of this transformation is a left exact functor. This functor and its
first derived functor are evaluated on the global sections of a line bundle on
the flag variety. It is conjectured that the derived functors of order greater
than one annihilate the global sections. Also, the principal indecomposable
modules for the Frobenius subgroups are shown to be acyclic.


title: A thermodynamic unification of jamming

abstract:
  Fragile materials ranging from sand to fire-retardant to toothpaste are able
to exhibit both solid and fluid-like properties across the jamming transition.
Unlike ordinary fusion, systems of grains, foams and colloids jam and cease to
flow under conditions that still remain unknown. Here we quantify jamming via a
thermodynamic approach by accounting for the structural ageing and the
shear-induced compressibility of dry sand. Specifically, the jamming threshold
is defined using a non-thermal temperature that measures the 'fluffiness' of a
granular mixture. The thermodynamic model, casted in terms of pressure,
temperature and free-volume, also successfully predicts the entropic data of
five molecular glasses. Notably, the predicted configurational entropy avoids
the Kauzmann paradox entirely. Without any free parameters, the proposed
equation-of-state also governs the mechanism of shear-banding and the
associated features of shear-softening and thickness-invariance.


title:
Orbital periods of cataclysmic variables identified by the SDSS. III.
  Time-series photometry obtained during the 2004/5 International Time Project
  on La Palma

abstract:
  We present time resolved CCD photometry of 15 cataclysmic variables (CVs)
identified by the Sloan Digital Sky Survey (SDSS). The data were obtained as
part of the 2004/05 International Time Programme on La Palma. We discuss the
morphology of the light curves and the CV subtypes and give accurate orbital
periods for 11 systems. Nine systems are found below the 2-3h orbital period
gap, of which five have periods within a few minutes of the ~80min minimum
orbital period. One system each is found within and above the gap. This
confirms the previously noted trend for a large fraction of short-period
systems among the SDSS CVs. Objects of particular interest are SDSSJ0901+4809
and SDSSJ1250+6655 which are deeply eclipsing. SDSSJ0854+3905 is a polar with
an extremely modulated light curve, which is likely due to a mixture of
cyclotron beaming and eclipses of the accretion region by the white dwarf. One
out of five systems with white-dwarf dominated optical spectra exhibits
non-radial pulsations.


title:
Qtier-Rapor: Managing Spreadsheet Systems & Improving Corporate
  Performance, Compliance and Governance

abstract:
  Much of what EuSpRIG discusses is concerned with the integrity of individual
spreadsheets. In businesses, interlocking spreadsheets are regularly used to
fill functional gaps in core administrative systems. The growth and deployment
of such integrated spreadsheet SYSTEMS raises the scale of issues to a whole
new level. The correct management of spreadsheet systems is necessary to ensure
that the business achieves its goals of improved performance and good corporate
governance, within the constraints of legislative compliance - poor management
will deliver the opposite. This paper is an anatomy of the real-life issues of
the commercial use of spreadsheets in business, and demonstrates how
Qtier-Rapor has been used to instil best practice in the use of integrated
commercial spreadsheet systems.


title:
Coordination of Mathematics and Physical Resources by Physics Graduate
  Students

abstract:
  We investigate the dynamics of how graduate students coordinate their
mathematics and physics knowledge within the context of solving a homework
problem for a plasma physics survey course. Students were asked to obtain the
complex dielectric function for a plasma with a specified distribution function
and find the roots of that expression. While all the 16 participating students
obtained the dielectric function correctly in one of two equivalent
expressions, roughly half of them (7 of 16) failed to compute the roots
correctly. All seven took the same initial step that led them to the incorrect
answer. We note a perfect correlation between the specific expression of
dielectric function obtained and the student's success in solving for the
roots. We analyze student responses in terms of a resources framework and
suggest routes for future research.


title:
Block Entanglement Entropy of Ground States with Long-Range Magnetic
  Order

abstract:
  In this paper we calculate the block entanglement entropies of spin models
whose ground states have perfect antiferromagnetic or ferromagnetic long-range
order. In the latter case the definition of entanglement entropy is extended to
properly take into account the ground state degeneracy. We find in both cases
the entropy grows logarithmically with the block size. Implication of our
results on states with general long-range order will be discussed.


title: Automated Termination Proofs for Logic Programs by Term Rewriting

abstract:
  There are two kinds of approaches for termination analysis of logic programs:
"transformational" and "direct" ones. Direct approaches prove termination
directly on the basis of the logic program. Transformational approaches
transform a logic program into a term rewrite system (TRS) and then analyze
termination of the resulting TRS instead. Thus, transformational approaches
make all methods previously developed for TRSs available for logic programs as
well. However, the applicability of most existing transformations is quite
restricted, as they can only be used for certain subclasses of logic programs.
(Most of them are restricted to well-moded programs.) In this paper we improve
these transformations such that they become applicable for any definite logic
program. To simulate the behavior of logic programs by TRSs, we slightly modify
the notion of rewriting by permitting infinite terms. We show that our
transformation results in TRSs which are indeed suitable for automated
termination analysis. In contrast to most other methods for termination of
logic programs, our technique is also sound for logic programming without occur
check, which is typically used in practice. We implemented our approach in the
termination prover AProVE and successfully evaluated it on a large collection
of examples.


title: EuSpRIG 2006 Commercial Spreadsheet Review

abstract:
  This management summary provides an outline of a commercial spreadsheet
review process. The aim of this process is to ensure remedial or enhancement
work can safely be undertaken on a spreadsheet with a commercially acceptable
level of risk of introducing new errors.


title: Essential dimension of abelian varieties over number fields

abstract:
  We affirmatively answer a conjecture in the preprint ``Essential dimension
and algebraic stacks,'' proving that the essential dimension of an abelian
variety over a number field is infinite.


title: Homotopical Intersection Theory, II: equivariance

abstract:
  This is the second in a series of papers. Here we develop here an
intersection theory for manifolds equipped with an action of a finite group. As
in our previous paper, our approach will be homotopy theoretic, enabling us to
circumvent the specter of equivariant transversality.
  This theory has applications to embedding problems, equivariant fixed point
theory and the problem of enumerating the periodic points of a self map of a
compact smooth manifold.


title:
Another approach to decide on real root existence for univariate
  Polynomials, and a multivariate extension for 3-SAT

abstract:
  We present six Theorems on the univariate real Polynomial, using which we
develop a new algorithm for deciding the existence of atleast one real root for
univariate integer Polynomials. Our algorithm outputs that no positive real
root exists, if and only if, the given Polynomial is a factor of a real
Polynomial with positive coefficients. Next, we define a transformation that
transforms any instance of 3-SAT into a multivariate real Polynomial with
positive coefficients, if and only if, the instance is not satisfiable.


title: Searching for Directly Decaying Gluinos at the Tevatron

abstract:
  This letter describes how to perform searches over the complete
kinematically-allowed parameter space for new pair-produced color octet
particles that each subsequently decay into two jets plus missing energy at the
Tevatron. This letter shows that current searches can miss otherwise
discoverable spectra of particles due to CMSSM-motivated cuts. Optimizing the
HT and MET cuts expands the sensitivity of these searches.


title: On the detection of the finite frequency current fluctuations

abstract:
  We consider a measurement of finite-frequency current fluctuations, using a
resonance circuit as a model for the detector. We arrive at an expression for
the measurable response in terms of the current-current correlators which
differs from the standard (symmetrized) formula. The possibility of detection
of vacuum fluctuations is discussed.


title: The Robotic Super-LOTIS Telescope: Results & Future Plans

abstract:
  We provide an overview of the robotic Super-LOTIS (Livermore Optical
Transient Imaging System) telescope and present results from gamma-ray burst
(GRB) afterglow observations using Super-LOTIS and other Steward Observatory
telescopes. The 0.6-m Super-LOTIS telescope is a fully robotic system dedicated
to the measurement of prompt and early time optical emission from GRBs. The
system began routine operations from its Steward Observatory site atop Kitt
Peak in April 2000 and currently operates every clear night. The telescope is
instrumented with an optical CCD camera and a four position filter wheel. It is
capable of observing Swift Burst Alert Telescope (BAT) error boxes as early or
earlier than the Swift UV/Optical Telescope (UVOT). Super-LOTIS complements the
UVOT observations by providing early R- and I-band imaging. We also use the
suite of Steward Observatory telescopes including the 1.6-m Kuiper, the 2.3-m
Bok, the 6.5-m MMT, and the 8.4-m Large Binocular Telescope to perform
follow-up optical and near infrared observations of GRB afterglows. These
follow-up observations have traditionally required human intervention but we
are currently working to automate the 1.6-m Kuiper telescope to minimize its
response time.


title: Global Conservation Laws and Femtoscopy of Small Systems

abstract:
  It is important to understand, in detail, two-pion correlations measured in
p+p and d+A collisions. In particular, one wishes to understand the femtoscopic
correlations, in order to compare to similar measurements in heavy ion
collisions. However, in the low-multiplicity final states of these systems,
global conservation laws generate significant N-body correlations which project
onto the two-pion space in non-trivial ways and complicate the femtoscopic
analysis. We discuss a formalism to calculate and account for these
correlations in collisions dominated by a single particle species (e.g. pions).
We also discuss effects on two-particle correlations between non-identical
particles, the understanding of which may be important in the study of
femtoscopic space-time asymmetries.


title: What to expect from $U(n)$ Seiberg-Witten monopoles for $n > 1$

abstract:
  We study generalisations to the structure groups U(n) of the familiar
(abelian) Seiberg-Witten monopole equations on a four-manifold $X$ and their
moduli spaces. For $n=1$ one obtains the classical monopole equations. For $n >
1$ our results indicate that there should not be any non-trivial
gauge-theoretical invariants which are obtained by the scheme `evaluation of
cohomology classes on the fundamental cycle of the moduli space'. For, if
$b_2^+$ is positive the moduli space should be `cobordant' to the empty space
because we can deform the equations so as the moduli space of the deformed
equations is generically empty. Furthermore, on K\"ahler surfaces with $b_2^+ >
1$, the moduli spaces become empty as soon as we perturb with a non-vanishing
holomorphic 2-form.


title: On the detection of zero-point current and voltage fluctuations

abstract:
  It this paper we consider various methods for measuring current fluctuations.
It is shown, that the {\it temporal} zero-point fluctuations of current are
measurable in a natural set-ups.


title: $PU(N)$ monopoles, higher rank instantons, and the monopole invariants

abstract:
  A famous conjecture in gauge theory mathematics, attributed to Witten,
suggests that the polynomial invariants of Donaldson are expressible in terms
of the Seiberg-Witten invariants if the underlying four-manifold is of simple
type. Mathematicians have sought a proof of the conjecture by means of a
`cobordism program' involving $PU(2)$ monopoles. A higher rank version of the
Donaldson invariants was recently introduced by Kronheimer. Before being
defined, the physicists Mari\~no and Moore had already suggested that there
should be a generalisation of Witten's conjecture to this type of invariants.
We adopt a generalisation of the cobordism program to the higher rank situation
by studying $PU(N)$ monopoles. We analyse the differences to the $PU(2)$
situation, yielding evidence that a generalisation of Witten's conjecture
should hold.


title: Tidal Heating of Extra-Solar Planets

abstract:
  Extra-solar planets close to their host stars have likely undergone
significant tidal evolution since the time of their formation. Tides probably
dominated their orbital evolution once the dust and gas had cleared away, and
as the orbits evolved there was substantial tidal heating within the planets.
The tidal heating history of each planet may have contributed significantly to
the thermal budget that governed the planet's physical properties, including
its radius, which in many cases may be measured by observing transit events.
Typically, tidal heating increases as a planet moves inward toward its star and
then decreases as its orbit circularizes. Here we compute the plausible heating
histories for several planets with measured radii, using the same tidal
parameters for the star and planet that had been shown to reconcile the
eccentricity distribution of close-in planets with other extra-solar planets.
Several planets are discussed, including for example HD 209458 b, which may
have undergone substantial tidal heating during the past billion years, perhaps
enough to explain its large measured radius. Our models also show that GJ 876 d
may have experienced tremendous heating and is probably not a solid, rocky
planet. Theoretical models should include the role of tidal heating, which is
large, but time-varying.


title: Search for Cosmic Strings in the GOODS Survey

abstract:
  We search Hubble Space Telescope Treasury Program images collected as part of
the Great Observatories Origins Deep Survey for pairs of galaxies consistent
with the gravitational lensing signature of a cosmic string. Our technique
includes estimates of the efficiency for finding the lensed galaxy pair. In the
north (south) survey field we find no evidence out to a redshift of greater
than 0.5 (0.3) for cosmic strings to a mass per unit length limit of
$G\mu<3.0x10^{-7}$ at 95% confidence limits (C.L.). In the combined 314.9
arcmin$^2$ of the north and south survey fields this corresponds to a global
limit on $\Omega_{strings}<0.02$. Our limit on $G\mu$ is more than an order of
magnitude lower than searches for individual strings in cosmic microwave
background (CMB) data. Our limit is higher than other CMB and gravitational
wave searches, however, we note that it is less model dependent than these
other searches.


title:
Indirect exchange coupling between localized magnetic moments in carbon
  nanotubes: a dynamic approach

abstract:
  Magnetic moments dilutely dispersed in a metallic host tend to be coupled
through the conduction electrons of the metal. This indirect exchange coupling,
known to occur for a variety of magnetic materials embedded in several
different metallic structures, is of rather long range, especially for
low-dimensional structures like carbon nanotubes. Motivated by recent claims
that the indirect coupling between magnetic moments in precessional motion has
a much longer range than its static counterpart, here we consider how magnetic
atoms adsorbed to the walls of a metallic nanotube respond to a time-dependent
perturbation that induces their magnetic moments to precess. By calculating the
frequency-dependent spin susceptibility we are able to identify resonant peaks
whose respective widths provide information about the dynamic aspect of the
indirect exchange coupling. We show that by departing from a purely static
representation to another in which the moments are allowed to precess, we
change from what is already considered a long range interaction to another
whose range is far superior. In other words, localized magnetic moments
embedded in a metallic structure can feel each other's presence more easily
when they are set in precessional motion. We argue that such an effect can have
useful applications leading to large-scale spintronics devices.


title: Generators for Rational Loop Groups and Geometric Applications

abstract:
  Uhlenbeck proved that a set of simple elements generates the group of
rational loops in GL(n,C) that satisfy the U(n)-reality condition. For an
arbitrary complex reductive group, a choice of representation defines a notion
of rationality and enables us to write down a natural set of simple elements.
Using these simple elements we prove generator theorems for the fundamental
representations of the remaining neo-classical groups and most of their
symmetric spaces. In order to apply our theorems to submanifold geometry we
also obtain explicit dressing and permutability formulae. We introduce a new
submanifold geometry associated to G_2/SO(4) to which our theory applies.


title:
First study of the radiation-amplitude zero in Wgamma production and
  limits on anomalous WWgamma couplings at sqrt(s)=1.96 TeV

abstract:
  We present results from a study of p-pbar -> W(gamma) + X events utilizing
data corresponding to 0.7 fb^{-1} of integrated luminosity at sqrt(s) = 1.96
TeV collected by the D0 detector at the Fermilab Tevatron Collider. We set
limits on anomalous WWgamma couplings at the 95% C.L. The one dimensional 95%
C.L. limits are 0.49 < kappa_{gamma} < 1.51 and -0.12 < lambda_{gamma} < 0.13.
We make the first study of the charge-signed rapidity difference between the
lepton and the photon and find it to be indicative of the standard model
radiation-amplitude zero in the Wgamma system.


title: A remark on minimal Fano threefolds

abstract:
  We prove in the case of minimal Fano threefolds a conjecture stated by
Dubrovin at the ICM 1998 in Berlin. The conjecture predicts that the
symmetrized/alternated Euler characteristic pairing on $K_0$ of a Fano variety
with an exceptional collection expressed in the basis of the classes of the
exceptional objects coincides with the intersection pairing of the vanishing
cycles in Dubrovin's second connection. We show that the conjecture holds for
$V_{22}$, a minimal Fano threefold of anticanonical degree~22, and for $V_5$,
the minimal Fano threefold of anticanonical degree~40, by applying the
modularity result for rank 1 Fano threefolds. The truth of the conjecture for
$\P ^3$ and the three--dimensional quadric is known; we consider these cases
for the sake of completeness.


title: Composition Attacks and Auxiliary Information in Data Privacy

abstract:
  Privacy is an increasingly important aspect of data publishing. Reasoning
about privacy, however, is fraught with pitfalls. One of the most significant
is the auxiliary information (also called external knowledge, background
knowledge, or side information) that an adversary gleans from other channels
such as the web, public records, or domain knowledge. This paper explores how
one can reason about privacy in the face of rich, realistic sources of
auxiliary information. Specifically, we investigate the effectiveness of
current anonymization schemes in preserving privacy when multiple organizations
independently release anonymized data about overlapping populations. 1. We
investigate composition attacks, in which an adversary uses independent
anonymized releases to breach privacy. We explain why recently proposed models
of limited auxiliary information fail to capture composition attacks. Our
experiments demonstrate that even a simple instance of a composition attack can
breach privacy in practice, for a large class of currently proposed techniques.
The class includes k-anonymity and several recent variants. 2. On a more
positive note, certain randomization-based notions of privacy (such as
differential privacy) provably resist composition attacks and, in fact, the use
of arbitrary side information. This resistance enables stand-alone design of
anonymization schemes, without the need for explicitly keeping track of other
releases. We provide a precise formulation of this property, and prove that an
important class of relaxations of differential privacy also satisfy the
property. This significantly enlarges the class of protocols known to enable
modular design.


title:
Ultra-Low-Energy Germanium Detector for Neutrino-Nucleus Coherent
  Scattering and Dark Matter Searches

abstract:
  The status and plans of a research program on the development of
ultra-low-energy germanium detectors with sub-keV sensitivities are reported.
We survey the scientific goals which include the observation of
neutrino-nucleus coherent scattering, the studies of neutrino magnetic moments,
as well as the searches of WIMP dark matter. In particular, a threshold of
100-200 eV and a sub-keV background comparable to underground experiments were
achieved with prototype detectors. New limits were set for WIMPs with mass
between 3-6 GeV. The prospects of the realization of full-scale experiments are
discussed.


title:
From a set of parts to an indivisible whole. Part I: Operations in a
  closed mode

abstract:
  This paper provides a description of a new method for information processing
based on holistic approach wherein analysis is a direct product of synthesis.
The core of the method is iterative averaging of all the elements of a system
according to all the parameters describing the elements. Contrary to common
logic, the iterative averaging of a system's elements does not result in
homogenization of the system; instead, it causes an obligatory subdivision of
the system into two alternative subgroups, leaving no outliers. Within each of
the formed subgroups, similarity coefficients between the elements reach the
value of 1, whereas similarity coefficients between the elements of different
subgroups equal a certain constant value greater than 0 but lower than 1. When
subjected to iterative averaging, any system consisting of three or more
elements of which at least two elements are not completely identical undergo
such a process of bifurcation that occurs non-linearly. Successive iterative
averaging of each of the forming subgroups eventually provides a hierarchical
system that reflects relationships between the elements of an input system
under analysis. We propose a definition of a natural hierarchy that can exist
only in conditions of closeness of a system and can be discovered upon
providing such an effect onto a system which allows its elements interact with
each other based on the principle of self-organization. Self-organization can
be achieved through an overall and total cross-averaging of a system's
elements. We demonstrate the application potentials of the proposed technology
on a number of examples, including a system of scattered points, randomized
datasets, as well as meteorological and demographical datasets.


title: Cauchy_Riemann Equations for Cayley Numbers` Functions

abstract:
  Since the discovery of octonions in 1843 we seem to be still lacking a
satisfactory if any theory of octave valued functions satisfactory according to
standard requirements or expectation from the side of a theory like a one might
look for. Here is a proposal coming back to my twentieth century presentation
of a perhaps nonstandard idea hoping to be coping with nonassociativity by an
invention.


title: Muon Capture on 3He and the Weak Structure of the Nucleon

abstract:
  The weak form factors of the nucleon, including the induced pseudoscalar form
factor and second class terms, are constrained using a microscopic calculation
of the weak capture process $^3He(\mu^{-},\nu_\mu)^3{H}$. The calculation is
parameter free, and yields a rate of 1499(16) Hz, in agreement with the
remarkable experimental measurement 1496(4) Hz. The nuclear wave functions are
obtained using the EIHH method with the Argonne V18 nucleon--nucleon potential
and the Urbana-IX three nucleon force. The weak currents in the nuclei are
described using HB$\chi$PT formalism. The induced pseudoscalar form factor is
found to agree with HB$\chi$PT prediction. The result is compatible with
vanishing second class currents, with the tightest constraint to date on the
conservation of vector current (CVC) hypothesis.


title: A Survey on Deep Packet Inspection for Intrusion Detection Systems

abstract:
  Deep packet inspection is widely recognized as a powerful way which is used
for intrusion detection systems for inspecting, deterring and deflecting
malicious attacks over the network. Fundamentally, almost intrusion detection
systems have the ability to search through packets and identify contents that
match with known attacks. In this paper, we survey the deep packet inspection
implementations techniques, research challenges and algorithms. Finally, we
provide a comparison between the different applied systems.


title: External Fields and Chiral Symmetry Breaking in the Sakai-Sugimoto Model

abstract:
  Using the Sakai-Sugimoto model we study the effect of an external magnetic
field on the dynamics of fundamental flavours in both the confined and
deconfined phases of a large N_c gauge theory. We find that an external
magnetic field promotes chiral symmetry breaking, consistent with the "magnetic
catalysis" observed in the field theory literature, and seen in other studies
using holographic duals. The external field increases the separation between
the deconfinement temperature and the chiral symmetry restoring temperature. In
the deconfined phase we investigate the temperature-magnetic field phase
diagram and observe, for example, there exists a maximum critical temperature
(at which symmetry is restored) for very large magnetic field. We find that
this and certain other phenomena persist for the Sakai-Sugimoto type models
with probe branes of diverse dimensions. We comment briefly on the dynamics in
the presence of an external electric field.


title: Well-posedness of the IBVP for 2-D Euler Equations with Damping

abstract:
  In this paper we focus on the initial-boundary value problem of the 2-D
isentropic Euler equations with damping. We prove the global-in-time existence
of classical solution to the initial-boundary value problem by the method of
energy estimates.


title:
Minimal distance transformations between links and polymers: Principles
  and examples

abstract:
  The calculation of Euclidean distance between points is generalized to
one-dimensional objects such as strings or polymers. Necessary and sufficient
conditions for the minimal transformation between two polymer configurations
are derived. Transformations consist of piecewise rotations and translations
subject to Weierstrass-Erdmann corner conditions. Numerous examples are given
for the special cases of one and two links. The transition to a large number of
links is investigated, where the distance converges to the polymer length times
the mean root square distance (MRSD) between polymer configurations, assuming
curvature and non-crossing constraints can be neglected. Applications of this
metric to protein folding are investigated. Potential applications are also
discussed for structural alignment problems such as pharmacophore
identification, and inverse kinematic problems in motor learning and control.


title: Banach Spaces with respect to Operator-Valued Norms

abstract:
  We introduce the notions of L(H)-valued norms and Banach spaces with respect
to L(H)-valued norms. In particular, we introduce Hilbert spaces with respect
to L(H)-valued inner products. In addition, we provide several fundamental
examples of Hilbert spaces with respect to L(H)-valued inner products.


title:
Combinatorial discovery of a lead-free morphotropic phase boundary in a
  thin-film piezoelectric perovskite

abstract:
  We report on the discovery of a lead-free morphotropic phase boundary in Sm
doped BiFeO3 with a simple perovskite structure using the combinatorial thin
film strategy. The boundary is a rhombohedral to pseudo-orthorhombic structural
transition which exhibits a ferroelectric (FE) to antiferroelectric (AFE)
transition at approximately Bi0.86Sm0.14FeO3 with dielectric constant and
out-of-plane piezoelectric coefficient comparable to those of epitaxial (001)
oriented Pb(Zr,Ti)O3 (PZT) thin films at the MPB. The discovered composition
may be a strong candidate of a Pb-free piezoelectric replacement of PZT.


title: Some graphs related to Thompson's group F

abstract:
  The Schreier graphs of Thompson's group F with respect to the stabilizer of
1/2 and generators x_0 and x_1, and of its unitary representation in L_2([0,1])
induced by the standard action on the interval [0,1] are explicitly described.
The coamenability of the stabilizers of any finite set of dyadic rational
numbers is established. The induced subgraph of the right Cayley graph of the
positive monoid of F containing all the vertices of the form x_nv, where n>=0
and v is any word over the alphabet {x_0, x_1}, is constructed. It is proved
that the latter graph is non-amenable.


title: Intra-Landau level Cyclotron Resonance in Bilayer Graphene

abstract:
  Interaction driven integer quantum Hall effects are anticipated in graphene
bilayers because of the near-degeneracy of the eight Landau levels which appear
near the neutral system Fermi level. We predict that an intra-Landau-level
cyclotron resonance signal will appear at some odd-integer filling factors,
accompanied by collective modes which are nearly gapless and have approximate
$k^{3/2}$ dispersion. We speculate on the possibility of unususal localization
physics associated with these modes.


title: Direct limits of infinite-dimensional Lie groups

abstract:
  Many infinite-dimensional Lie groups of interest can be expressed as a union
of an ascending sequence of (finite- or infinite-dimensional) Lie groups. In
this survey article, we compile general results concerning such ascending
unions, describe the main classes of examples, and explain what the general
theory tells us about these.
  In particular, we discuss:
  (1) Direct limit properties of ascending unions of Lie groups in the relevant
categories;
  (2) Regularity in Milnor's sense;
  (3) Homotopy groups of direct limit groups and of Lie groups containing a
dense union of Lie groups;
  (4) Subgroups of direct limit groups;
  (5) Constructions of Lie group structures on ascending unions of Lie groups.


title:
One-Time Pad, Arithmetic Coding and Logic Gates: An unifying theme using
  Dynamical Systems

abstract:
  In this letter, we prove that the perfectly secure One-Time Pad (OTP)
encryption can be seen as finding the initial condition on the binary map under
a random switch based on the perfectly random pad. This turns out to be a
special case of Grangetto's randomized arithmetic coding performed on the
Binary Map. Furthermore, we derive the set of possible perfect secrecy systems
using such an approach. Since OTP encryption is an XOR operation, we thus have
a dynamical systems implementation of the XOR gate. We show similar
implementations for other gates such as NOR, NAND, OR, XNOR, AND and NOT. The
dynamical systems framework unifies the three areas to which Shannon made
foundational contributions: lossless compression (Source Coding), perfect
encryption (Cryptography), and design of logic gates (Computation)


title: Ludwig Valentin Lorenz is the discoverer of the "Lorenz gauge"!

abstract:
  The letter reminds the historical fact that the known "Lorenz gauge" (or
"Lorenz condition/relation") is first mentioned in a written form and named
after Ludwig Valentin Lorenz and not by/after Hendrik Antoon Lorentz.

categories: physics.hist-ph hep-th math-ph math.MP physics.class-ph physics.gen-ph


title:
A Bit-Compatible Shared Memory Parallelization for ILU(k)
  Preconditioning and a Bit-Compatible Generalization to Distributed Memory

abstract:
  ILU(k) is a commonly used preconditioner for iterative linear solvers for
sparse, non-symmetric systems. It is often preferred for the sake of its
stability. We present TPILU(k), the first efficiently parallelized ILU(k)
preconditioner that maintains this important stability property. Even better,
TPILU(k) preconditioning produces an answer that is bit-compatible with the
sequential ILU(k) preconditioning. In terms of performance, the TPILU(k)
preconditioning is shown to run faster whenever more cores are made available
to it --- while continuing to be as stable as sequential ILU(k). This is in
contrast to some competing methods that may become unstable if the degree of
thread parallelism is raised too far. Where Block Jacobi ILU(k) fails in an
application, it can be replaced by TPILU(k) in order to maintain good
performance, while also achieving full stability. As a further optimization,
TPILU(k) offers an optional level-based incomplete inverse method as a fast
approximation for the original ILU(k) preconditioned matrix. Although this
enhancement is not bit-compatible with classical ILU(k), it is bit-compatible
with the output from the single-threaded version of the same algorithm. In
experiments on a 16-core computer, the enhanced TPILU(k)-based iterative linear
solver performed up to 9 times faster. As we approach an era of many-core
computing, the ability to efficiently take advantage of many cores will become
ever more important. TPILU(k) also demonstrates good performance on cluster or
Grid. For example, the new algorithm achieves 50 times speedup with 80 nodes
for general sparse matrices of dimension 160,000 that are diagonally dominant.


title: On Fuglede's conjecture for three intervals

abstract:
  In this paper we prove the "Tiling implies Spectral" part of Fuglede's paper
for the case of three intervals. Then we prove the "Spectral implies Tiling"
part of the conjecture for the case of three equal intervals as also when the
intervals have lengths 1/2, 1/4, 1/4. For the general case we change our
approach to get information on the structure of the spectrum for the n-interval
case. Finally, we use symbolic computations on Mathematica, and prove this part
of the conjecture with an additional assumption on the spectrum.


title: Hilbertian Repulsive Effect and Dark Energy

abstract:
  A repulsive gravitational effect of general relativity (without cosmological
term), which was pointed out by Hilbert many years ago, could play a decisive
role in the explanation of the observational data concerning the accelerated
expansion of the universe.


title:
Ordering of the pyrochlore Ising model with the long-range RKKY
  interaction

abstract:
  The ordering of the Ising model on a pyrochlore lattice interacting via the
long-range RKKY interaction, which models a metallic pyrochlore magnet such as
Pr_2Ir_2O_7, is studied by Monte Carlo simulations. Depending on the parameter
k_F representing the Fermi wavevector, the model exhibits rich ordering
behaviors.


title:
Spin-orbit interaction effect in the electronic structure of \BiTe \
  observed by angle-resolved photoemission spectroscopy

abstract:
  The electronic structure of $p$-type doped \BiTe is studied by angle resolved
photoemission spectroscopy (ARPES) to experimentally confirm the mechanism
responsible for the high thermoelectric figure of merit. Our ARPES study shows
that the band edges are located off the $\Gamma$-Z line in the Brillouin zone,
which provides direct observation that the spin-orbit interaction is a key
factor to understand the electronic structure and the corresponding
thermoelectric properties of \BiTe. Successive time dependent ARPES measurement
also reveals that the electron-like bands crossing E$_F$ near the
$\underline{\Gamma}$ point are formed in an hour after cleaving the crystals.
We interpret these as surface states induced by surface band bending, possibly
due to quintuple inter-layer distance change of \BiTe.


title: Mobile Agents for Content-Based WWW Distributed Image Retrieval

abstract:
  At present, the de-facto standard for providing contents in the Internet is
the World Wide Web. A technology, which is now emerging on the Web, is
Content-Based Image Retrieval (CBIR). CBIR applies methods and algorithms from
computer science to analyse and index images based on their visual content.
Mobile agents push the flexibility of distributed systems to their limits since
not only computations are dynamically distributed but also the code that
performs them. The current commercial applet-based methodologies for accessing
image database systems offer limited flexibility, scalability and robustness.
In this paper the author proposes a new framework for content-based WWW
distributed image retrieval based on Java-based mobile agents. The
implementation of the framework shows that its performance is comparable to,
and in some cases outperforms, the current approach.


title:
Adaptive methods for sequential importance sampling with application to
  state space models

abstract:
  In this paper we discuss new adaptive proposal strategies for sequential
Monte Carlo algorithms--also known as particle filters--relying on criteria
evaluating the quality of the proposed particles. The choice of the proposal
distribution is a major concern and can dramatically influence the quality of
the estimates. Thus, we show how the long-used coefficient of variation of the
weights can be used for estimating the chi-square distance between the target
and instrumental distributions of the auxiliary particle filter. As a
by-product of this analysis we obtain an auxiliary adjustment multiplier weight
type for which this chi-square distance is minimal. Moreover, we establish an
empirical estimate of linear complexity of the Kullback-Leibler divergence
between the involved distributions. Guided by these results, we discuss
adaptive designing of the particle filter proposal distribution and illustrate
the methods on a numerical example.


title: A compact topology for sand automata

abstract:
  In this paper, we exhibit a strong relation between the sand automata
configuration space and the cellular automata configuration space. This
relation induces a compact topology for sand automata, and a new context in
which sand automata are homeomorphic to cellular automata acting on a specific
subshift. We show that the existing topological results for sand automata,
including the Hedlund-like representation theorem, still hold. In this context,
we give a characterization of the cellular automata which are sand automata,
and study some dynamical behaviors such as equicontinuity. Furthermore, we deal
with the nilpotency. We show that the classical definition is not meaningful
for sand automata. Then, we introduce a suitable new notion of nilpotency for
sand automata. Finally, we prove that this simple dynamical behavior is
undecidable.


title:
A 5-Dimensional Spherical Symmetric Solution in Einstein-Yang-Mills
  Theory With Gauss-Bonnet Term

abstract:
  We present a numerical solution on a 5-dimensional spherically symmetric
space time, in Einstein-Yang-Mills-Gauss-Bonnet theory using a two point
boundary value routine. It turns out that the Gauss-Bonnet contribution has a
profound influence on the behaviour of the particle-like solution: it increases
the number of nodes of the YM field. When a negative cosmological constant in
incorporated in the model, it turns out that there is no horizon and no
singular behaviour of the model. For positive cosmological constant the model
has singular behaviour.


title: Cross-correlations in Warsaw Stock Exchange

abstract:
  We study the inter-stock correlations for the largest companies listed on
Warsaw Stock Exchange and included in the WIG20 index. Our results from the
correlation matrix analysis indicate that the Polish stock market can be well
described by a one factor model. We also show that the stock-stock correlations
tend to increase with the time scale of returns and they approach a saturation
level for the time scales of at least 200 min, i.e. an order of magnitude
longer than in the case of some developed markets. We also show that the
strength of correlations among the stocks crucially depends on their
capitalization. These results combined with our earlier findings together
suggest that now the Polish stock market situates itself somewhere between an
emerging market phase and a mature market phase.


title:
An explicit classification for the cyclic rational torsion subgroups of
  odd order of elliptic curves over $ \Q $

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


title: Probing Mott lobes via the AC Josephson effect

abstract:
  The alternating-current (AC) Josephson effect is studied in a system
consisting of two weakly coupled Bose Hubbard models. In the framework of the
mean field theory, Gross-Pitaevskii equations show that the amplitude of the
Josephson current is proportional to the product of superfluid order
parameters. In addition, the chemical potential--current relation for a small
size system is obtained via the exact numerical computation. This allows us to
propose a feasible experimental scheme to measure the Mott lobes of the quantum
phase transition.


title: Q-valued functions revisited

abstract:
  In this note we revisit Almgren's theory of Q-valued functions, that are
functions taking values in the space of unordered Q-tuples of points in R^n. In
particular: 1) we give shorter versions of Almgren's proofs of the existence of
Dir-minimizing Q-valued functions, of their Hoelder regularity and of the
dimension estimate of their singular set; 2) we propose an alternative
intrinsic approach to these results, not relying on Almgren's biLipschitz
embedding; 3) we improve upon the estimate of the singular set of planar
Dir-minimizing functions by showing that it consists of isolated points.


title:
Radiative decays of vector mesons in the gauge model of quark-meson
  interactions

abstract:
  We consider meson radiative decays within the framework of $U_0(1)\times
U(1)\times SU(2)$ gauge symmetry. This approach is based on the linear
sigma-model extended by the gauge and quark-meson interactions. Physical
content and parameters of the model are discussed. Theoretical predictions for
some radiative decays of vector mesons are in a good agreement with the
experimental data.


title:
B_s^0-\bar{B}_s^0 mixing and B -> \pi K decays in stringy leptophobic
  Z^\prime

abstract:
  We consider a leptophobic Z^\prime scenario in a flipped SU(5) grand unified
theory obtained from heterotic string theory. We show that the allowed Z^\prime
mass, flavor conserving and flavor changing couplings of the Z^\prime to the
down-type quarks are strongly constrained by the mass difference in
B_s-\bar{B}_s system and the four branching ratios of B -> \pi K decays. It is
shown that even under these constraints large deviations in direct and/or
indirect CP asymmetries of B \to \pi K decays from the SM expectations are
allowed. Especially it is possible to accommodate the apparent puzzling data in
B -> \pi K CP asymmetries.


title: Unresolved emission and ionized gas in the bulge of M31

abstract:
  We study the origin of unresolved X-ray emission from the bulge of M31 based
on archival Chandra and XMM-Newton observations. We demonstrate that three
different components are present: (i) Broad-band emission from a large number
of faint sources -- mainly accreting white dwarfs and active binaries,
associated with the old stellar population, similar to the Galactic Ridge X-ray
emission of the Milky Way. The X-ray to K-band luminosity ratios are compatible
with those for the Milky Way and for M32, in the 2 - 10 keV band it is (3.6 +/-
0.2) x 10^27 erg/s/L_sun. (ii) Soft emission from ionized gas with temperature
of about ~ 300 eV and mass of ~ 2 x 10^6 M_sun. The gas distribution is
significantly extended along the minor axis of the galaxy suggesting that it
may be outflowing in the direction perpendicular to the galactic disk. The mass
and energy supply from evolved stars and type Ia supernovae is sufficient to
sustain the outflow. We also detect a shadow cast on the gas emission by spiral
arms and the 10-kpc star-forming ring, confirming significant extent of the gas
in the ``vertical'' direction. (iii) Hard extended emission from spiral arms,
most likely associated with young stellar objects and young stars located in
the star-forming regions. The L_X/SFR ratio equals ~ 9 x 10^38
(erg/s)/(M_sun/yr) which is about ~ 1/3 of the HMXBs contribution, determined
earlier from Chandra observations of other nearby galaxies.


title: Homological properties of Orlik-Solomon algebras

abstract:
  The Orlik-Solomon algebra of a matroid can be considered as a quotient ring
over the exterior algebra E. At first we study homological properties of
E-modules as e.g. complexity, depth and regularity. In particular, we consider
modules with linear injective resolutions. We apply our results to
Orlik-Solomon algebras of matroids and give formulas for the complexity, depth
and regularity of such rings in terms of invariants of the matroid. Moreover,
we characterize those matroids whose Orlik-Solomon ideal has a linear
projective resolution and compute in these cases the Betti numbers of the
ideal.


title: Electrified Fluctuations in D1$\bot$D3 and D1$\bot$D5 Systems

abstract:
  We present the physical phenomenon of the subject discussed in the paper
\cite{fluc}. In that paper we dealt with the fluctuations of funnel solutions
of intersecting D1 and D3 branes and the electric field $E$ was considered as
very high value causing the results to be non-physical. In the present work,
the variation interval of $E$ is to be $[0,\frac{1}{\lambda}[$. Then, we extend
the study to discuss the overall transverse fluctuations of electrified funnel
solutions of D1$\bot$D5 system in the flat background. The boundary conditions
are found to be Neumann boundary conditions.


title: Search For Iron, Nickel, and Fluorine in PG1159 Stars

abstract:
  A possible origin of the iron-deficiency in PG1159 stars could be neutron
captures on Fe nuclei. A nickel overabundance would corroborate this idea.
Consequently we are looking for nickel lines in PG1159 stars. Prime targets are
relatively cool objects, because Ni VI is the dominant ionisation stage and the
spectral lines of this ion are accessible with UV observations. We do not find
such lines in the coolest PG1159 star observed by FUSE (PG1707+427, Teff =
85,000 K) and conclude that the nickel abundance is not enhanced. Hence, the
Fe-deficiency in PG1159 stars remains unexplained. In addition, we present
results of a wind analysis of the hybrid-PG1159 star NGC 7094 and the
[WC]-PG1159 transition-type object Abell 78 in order to derive F abundances
from the F VI 1139.5 Angstrom line. In both cases, we find F overabundances, in
agreement with results of photospheric analyses of many PG1159 stars.
Surprisingly, we find indications for a very low O abundance in NGC 7094.


abstract:
  Uniaxially anisotropic antiferromagnets in a field along the easy axis are
studied with the help of ground state considerations and Monte Carlo
simulations. For classical models, the XXZ model as well as variants, we
analyze the role of non-collinear spin configurations of biconical or
bidirectional type interpolating between the well-known antiferromagnetic and
spin-flop structures. Possible experimental applications to layered cuprate
antiferromagnets are discussed. Finally, results of quantum Monte Carlo
simulations for the S=1/2 XXZ model on a square lattice are presented, and
compared with previous findings.


title: On perfect colorings of the halved 24-cube

abstract:
  A vertex 2-coloring of a graph is said to be perfect with parameters
$(a_{ij})_{i,j=1}^k$ if for every $i,j\in\{1,...,k\}$ every vertex of color $i$
is adjacent with exactly $a_{ij}$ vertices of color $j$. We consider the
perfect 2-colorings of the distance-2 graph of the 24-cube $\{0,1\}^{24}$ with
parameters $((20+c,256-c)(c,276-c))$ (i.e., with eigenvalue 20). We prove that
such colorings exist for all $c$ from 1 to 128 except 1, 2, 4, 5, 7, 10, 13 and
do not exist for $c=1, 2, 4, 5, 7$. Keywords: perfect coloring, equitable
partition, hypercube, halved n-cube


title: Finitary incidence algebras

abstract:
  We consider the functions in two variables on an arbitrary poset, for which
the convolution operation is defined. We obtain the generalization of incidence
algebra and describe its properties: invertibility, the Jackobson radical,
idempotents, regular elements. As a consequence a positive solution of the
isomorphism problem for such algebras is obtained.


title:
Spatial coherence resonance on diffusive and small-world networks of
  Hodgkin-Huxley neurons

abstract:
  Spatial coherence resonance in a spatially extended system that is locally
modeled by Hodgkin-Huxley (HH) neurons is studied in this paper. We focus on
the ability of additive temporally and spatially uncorrelated Gaussian noise to
extract a particular spatial frequency of excitatory waves in the medium,
whereby examining also the impact of diffusive and small-world network topology
determining the interactions amongst coupled HH neurons. We show that there
exists an intermediate noise intensity that is able to extract a characteristic
spatial frequency of the system in a resonant manner provided the latter is
diffusively coupled, thus indicating the existence of spatial coherence
resonance. However, as the diffusive topology of the medium is relaxed via the
introduction of shortcut links introducing small-world properties amongst
coupled HH neurons, the ability of additive Gaussian noise to evoke ordered
excitatory waves deteriorates rather spectacularly, leading to the decoherence
of the spatial dynamics and with it related absence of spatial coherence
resonance. In particular, already a minute fraction of shortcut links suffices
to substantially disrupt coherent pattern formation in the examined system.


title: On quasi-Frobenius semigroup algebras

abstract:
  We define quasi-Frobenius semigroups and find necessary and sufficient
conditions under which a semigroup algebra of a 0-cancellative semigroup is
quasi-Frobenius.


title: Parabolic polygons

abstract:
  Main Theorem. Two parabols have four common points. There exists a circle
tangent to the sides of the obtained parabolic quadrilateral if and only if the
diagonals of this quadrilateral are orthogonal.
  The proof of the Main Theorem is elementary and purely synthetic. It is based
on the following lemma. Assume that a parabola is tangent to a circle at points
A and B. A point P of the plane lyes on the parabola if and only if the
distance from the point P to the line AB equals to the length of the tangent
from P to the circle.
  We present some beautiful elementary corollaries of the Main Theorem.


title: A note on noncommutative unique ergodicity and weighted means

abstract:
  In this paper we study unique ergodicity of $C^*$-dynamical system $(\ga,T)$,
consisting of a unital $C^*$-algebra $\ga$ and a Markov operator
$T:\ga\mapsto\ga$, relative to its fixed point subspace, in terms of Riesz
summation which is weaker than Cesaro one. Namely, it is proven that $(\ga,T)$
is uniquely ergodic relative to its fixed point subspace if and only if its
Riesz means {equation*} \frac{1}{p_1+...+p_n}\sum_{k=1}^{n}p_kT^kx {equation*}
converge to $E_T(x)$ in $\ga$ for any $x\in\ga$, as $n\to\infty$, here $E_T$ is
an projection of $\ga$ to the fixed point subspace of $T$. It is also
constructed a uniquely ergodic entangled Markov operator relative to its fixed
point subspace, which is not ergodic.


title:
A codimension two CR singular submanifold that is formally equivalent to
  a symmetric quadric

abstract:
  Let $M\subset \mathbb{C}^{n+1}$ ($n\geq 2$) be a real analytic submanifold
defined by an equation of the form: $w=|z|^2+O(|z|^3)$, where we use $(z,w)\in
\mathbb{C}^{n}\times \mathbb{C}$ for the coordinates of $\mathbb{C}^{n+1}$. We
first derive a pseudo-normal form for $M$ near 0. We then use it to prove that
$(M,0)$ is holomorphically equivalent to the quadric $(M_\infty: w=|z|^2,0)$ if
and only if it can be formally transformed to $(M_\infty,0)$. We also use it to
give a necessary and sufficient condition when $(M,0)$ can be formally
flattened. The result is due to Moser for the case of $n=1$.


title: Tensor gauge boson production in high energy collisions

abstract:
  We calculated the leading-order cross section for the helicity two tensor
gauge bosons production in fermion pair annihilation process. We compare this
cross section with a similar annihilation processes in QED with two photons in
the final state and with two gluons in QCD.


title: A Poincar\'e section for the general heavy rigid body

abstract:
  A general recipe is developed for the study of rigid body dynamics in terms
of Poincar\'e surfaces of section. A section condition is chosen which captures
every trajectory on a given energy surface. The possible topological types of
the corresponding surfaces of section are determined, and their 1:1 projection
to a conveniently defined torus is proposed for graphical rendering.


title: Finite tight frames and some applications

abstract:
  A finite-dimensional Hilbert space is usually described in terms of an
orthonormal basis, but in certain approaches or applications a description in
terms of a finite overcomplete system of vectors, called a finite tight frame,
may offer some advantages. The use of a finite tight frame may lead to a
simpler description of the symmetry transformations, to a simpler and more
symmetric form of invariants or to the possibility to define new mathematical
objects with physical meaning, particularly in regard with the notion of a
quantization of a finite set. We present some results concerning the use of
integer coefficients and frame quantization, several examples and suggest some
possible applications.


title: Cluster Multi-spacecraft Determination of AKR Angular Beaming

abstract:
  Simultaneous observations of AKR emission using the four-spacecraft Cluster
array were used to make the first direct measurements of the angular beaming
patterns of individual bursts. By comparing the spacecraft locations and AKR
burst locations, the angular beaming pattern was found to be narrowly confined
to a plane containing the magnetic field vector at the source and tangent to a
circle of constant latitude. Most rays paths are confined within 15 deg of this
tangent plane, consistent with numerical simulations of AKR k-vector
orientation at maximum growth rate. The emission is also strongly directed
upward in the tangent plane, which we interpret as refraction of the rays as
they leave the auroral cavity. The narrow beaming pattern implies that an
observer located above the polar cap can detect AKR emission only from a small
fraction of the auroral oval at a given location. This has important
consequences for interpreting AKR visibility at a given location. It also helps
re-interpret previously published Cluster VLBI studies of AKR source locations,
which are now seen to be only a subset of all possible source locations. These
observations are inconsistent with either filled or hollow cone beaming models.


title:
The X-Ray Transient 080109 in NGC 2770: an X-Ray Flash Associated with a
  Normal Core-Collapse Supernova

abstract:
  Although it is generally thought that long-duration gamma-ray bursts (LGRBs)
are associated with core-collapse supernovae (SNe), so far only four pairs of
GRBs and SNe with firmly established connection have been found. All the four
GRB-SNe are among a special class of Type Ic--called the broad-lined SNe
indicative of a large explosion energy, suggesting that only a small fraction
of SNe Ibc have GRBs associated with them. This scheme has been refreshed by
the discovery of a bright X-ray transient in NGC 2770 on 9 January 2008, which
was followed by a rather normal Type Ib SN 2008D. In this paper, I argue that
the transient 080109 is an X-ray flash (XRF, the soft version of a GRB) because
of the following evidences: (1) The transient cannot be interpreted as a SN
shock breakout event; (2) The GRB X-ray flare interpretation is not supported
by the high-energy observation. Then I show that XRF 080109 satisfies the
well-known relation between the isotropic-equivalent energy and the peak
spectral energy for LGRBs, which highly strengthens the XRF interpretation.
Finally, I point out that, the peak spectral energy of XRF 080109 and the
maximum bolometric luminosity of SN 2008D agree with the
$E_{\gamma,\p}$--$L_{{\rm SN},\max}$ relationship of Li (2006), strengthening
the validity of the relationship. I speculate that events like XRF 080109 may
occur at a rate comparable to SNe Ibc, and a soft X-ray telescope devoted to
surveying for nearby X-ray flares will be very fruitful in discovering them.


title: Tracing a Disk Wind in NGC 3516

abstract:
  X-ray spectra of AGN often contain signatures indicative of absorption in
multiple layers of gas whose ionization-state and covering fraction may vary
with time. It has been unclear to date how much of the observed X-ray spectral
and timing behavior in AGN can be attributed to variations in absorption,
versus variations in the strengths of emission or reflection components.
Diagnostics of the inner regions of AGN cannot be reliably performed until the
origin of observed effects is understood. We investigate the role of the X-ray
absorbers in the Seyfert 1 galaxy NGC 3516. Time-averaged and flux-selected
spectroscopy is used to examine the behavior of NGC 3516 observed in Chandra
HETG and XMM data from Oct 2006. New H-like and He-like emission and absorption
features discovered in the Fe K regime reveal a previously unknown zone of
circumnuclear gas in NGC 3516 with log xi ~ 4.3 and column density 1E23 cm^-2.
A lower-ionization layer with log xi ~2 and of similar column density is
confirmed from previous observations, this layer has a covering fraction around
50%, and changes in covering provide a simple explanation of a deep dip in the
light curve that we interpret as an eclipse of the continuum due to passage of
a cloud across the sight line within half a day. These inner zones of absorbing
gas are detected to have outflow velocities in the range 1000-2000 km/s, this,
and constraints on radial location are consistent with an origin as part of a
disk wind in NGC 3516.


title: Linearized hydrodynamics from probe-sources in the gauge-string duality

abstract:
  We study the response of an infinite, asymptotically static N=4 plasma to a
generic localized source in the probe approximation. At large distances, the
energy momentum tensor of the plasma includes a term which satisfies the
constitutive relations of linearized hydrodynamics, but it can also include a
non-hydrodynamical term which contributes at the same order as viscous
corrections, or even at leading order in some cases. The conditions for the
appearance of a laminar wake far behind the source and its relevance for
phenomenological models used to explain di-hadron correlations are discussed.
We also consider the energy momentum tensor near the source, where the
hydrodynamical approximation can be expected to break down. Our analysis
encompasses a wide range of sources which are localized in the bulk of AdS,
including trailing strings, mesonic and baryonic configurations of strings, and
point particles.


title:
Measurements of D0-D0bar Mixing and Searches for CP Violation: HFAG
  Combination of all Data

abstract:
  We present world average values for D0-D0bar mixing parameters x and y, CP
violation parameters |q/p| and Arg(q/p), and strong phase differences \delta
and \delta_{K\pi\pi}. These values are calculated by the Heavy Flavor Averaging
Group (HFAG) by performing a global fit to relevant experimental measurements.
The results for x and y differ significantly from zero and are inconsistent
with no mixing at the level of 6.7 sigma. The results for |q/p| and Arg(q/p)
are consistent with no CP violation. The strong phase difference \delta is less
than 45 degrees at 95% C.L.


title:
Direct Methods and Symbolic Software for Conservation Laws of Nonlinear
  Equations

abstract:
  We present direct methods and symbolic software for the computation of
conservation laws of nonlinear partial differential equations (PDEs) and
differential-difference equations (DDEs).The methods are applied to nonlinear
PDEs in (1+1) dimensions with polynomial nonlinearities which include the
Korteweg-de Vries (KdV), Boussinesq, and Drinfel'd-Sokolov-Wilson equations. An
adaptation of the methods is applied to PDEs with transcendental
nonlinearities. Examples include the sine-Gordon, sinh-Gordon, and Liouville
equations.
  With respect to nonlinear DDEs, our methods are applied to Kac-van Moerbeke,
Toda, and Ablowitz-Ladik lattices. To overcome the shortcomings of the
undetermined coefficients method, we designed a new direct method which uses
leading order analysis. That method is applied to discretizations of the KdV
and modified KdV equations, and a combination thereof. Additional examples
include lattices due to Bogoyavlenskii, Belov-Chaltikian, and
Blaszak-Marciniak.
  The undetermined coefficient methods for PDEs and DDEs have been implemented
in Mathematica. The code "TransPDEDensityFlux.m" computes densities and fluxes
of systems of PDEs with or without transcendental nonlinearities. The code
"DDEDensityFlux.m" does the same for polynomial nonlinear DDEs. Starting from
the leading order terms, the new Maple library "discrete" computes densities
and fluxes of nonlinear DDEs.


title: PKS2250-41: a case study for triggering

abstract:
  We present the results of a multiwavelength study of the z = 0.31 radio
source PKS2250-41. Integral field unit and long-slit spectroscopy obtained
using VIMOS and FORS1 on the VLT, and archival HST optical imaging observations
are used to study the morphology, kinematics and ionisation state of the
extended emission line region (EELR) surrounding this source, and also a
companion galaxy at a similar redshift. Near-infrared imaging observations
obtained using the NTT are used to analyse the underlying galaxy morphologies.
The EELR displays a complex variety of different gas kinematics and ionization
states, consistent with a mixture of radio source shocks and AGN
photoionization. The radio galaxy is likely to lie within a group environment,
and is plausibly undergoing interactions with one or more other objects. The
disk-like galaxy to the northeast of the radio source lies at a similar
redshift to the radio galaxy itself, and has its major axis position angle
aligned with the filamentary continuum and line emission extending outwards
from the radio galaxy. This filamentary structure is most plausibly interpreted
as a tidal structure associated with an interaction involving the radio source
host galaxy and the aligned companion galaxy to the north-east; this encounter
may have potentially triggered the current epoch of radio source activity.
Overall, PKS2250-41 displays some of the best evidence that radio source
activity can be triggered in this manner. [abridged]


title:
Phase separation and the effect of quenched disorder in
  $Pr_{0.5}Sr_{0.5}MnO_3$

abstract:
  The nature of phase separation in $Pr_{0.5}Sr_{0.5}MnO_3$ has been probed by
linear as well as nonlinear magnetic susceptibilities and resistivity
measurements across the 2nd order paramagnetic to ferromagnetic transition
($T_C$) and 1st order ferromagnetic to antiferromagnetic transition ($T_N$). We
found that the ferromagnetic (metallic) clusters, which form with the onset of
long-range order in the system at $T_C$, continuously decrease their size with
the decrease in temperature and coexist with non-ferromagnetic (insulating)
clusters. These non-ferromagnetic clusters are identified to be
antiferromagnetic. Significantly, it is shown that they do not arise because of
the superheating effect of the lower temperature 1st order transition. Thus
reveals unique phase coexistence in a manganite around half-doping encompassing
two long-range order transitions. Both the ferromagnetic and antiferromagnetic
clusters form at $T_C$ and persist much below $T_N$. Substitution of quenched
disorder (Ga) at Mn-site promotes antiferromagnetism at the cost of
ferromagnetism without adding any magnetic interaction or introducing any
significant lattice distortion. Moreover, increase in disorder decreases the
ferromagnetic cluster size and with 7.5% Ga substitution clusters size reduces
to the single domain limit. Yet, all the samples show significant short-range
ferromagnetic interaction much above $T_C$. Resistivity measurements also
reveal the novel phase coexistence identified from the magnetic measurements.
It is significant that, increase in disorder up to 7.5% increases the
resistivity of the low temperature antiferromagnetic phase by about four
orders.