title:
Deriving Stellar Effective Temperatures of Metal-Poor Stars with the
  Excitation Potential Method

abstract:
  It is well established that stellar effective temperatures determined from
photometry and spectroscopy yield systematically different results. We describe
a new, simple method to correct spectroscopically derived temperatures
("excitation temperatures") of metal-poor stars based on a literature sample
with -3.3<[Fe/H]<-2.5. Excitation temperatures were determined from FeI line
abundances in high-resolution optical spectra in the wavelength range of ~3700
to ~7000A, although shorter wavelength ranges, up to 4750 to 6800A, can also be
employed, and compared with photometric literature temperatures. Our adjustment
scheme increases the temperatures up to several hundred degrees for cool red
giants, while leaving the near-main-sequence stars mostly unchanged. Hence, it
brings the excitation temperatures in good agreement with photometrically
derived values. The modified temperature also influences other stellar
parameters, as the FeI-FeII ionization balance is simultaneously used to
determine the surface gravity, while also forcing no abundance trend on the
absorption line strengths to obtain the microturbulent velocity. As a result of
increasing the temperature, the often too low gravities and too high
microturbulent velocities in red giants become higher and lower, respectively.
Our adjustment scheme thus continues to build on the advantage of deriving
temperatures from spectroscopy alone, independent of reddening, while at the
same time producing stellar chemical abundances that are more straightforwardly
comparable to studies based on photometrically derived temperatures. Hence, our
method may prove beneficial for comparing different studies in the literature
as well as the many high-resolution stellar spectroscopic surveys that are or
will be carried out in the next few years.


title:
Candidate super star cluster progenitor gas clouds possibly triggered by
  close passage to Sgr A*

abstract:
  Super star clusters are the end product of star formation under the most
extreme conditions. As such, studying how their final stellar populations are
assembled from their natal progenitor gas clouds can provide strong constraints
on star formation theories. An obvious place to look for the initial conditions
of such extreme stellar clusters are gas clouds of comparable mass and density,
with no star formation activity. We present a method to identify such
progenitor gas clouds and demonstrate the technique for the gas in the inner
few hundred pc of our Galaxy. The method highlights three clouds in the region
with similar global physical properties to the previously identified extreme
cloud, G0.253+0.016, as potential young massive cluster (YMC) precursors. The
fact that four potential YMC progenitor clouds have been identified in the
inner 100 pc of the Galaxy, but no clouds with similar properties have been
found in the whole first quadrant despite extensive observational efforts, has
implications for cluster formation/destruction rates across the Galaxy. We put
forward a scenario to explain how such dense gas clouds can arise in the
Galactic centre environment, in which YMC formation is triggered by gas streams
passing close to the minimum of the global Galactic gravitational potential at
the location of the central supermassive black hole, Sgr A*. If this triggering
mechanism can be verified, we can use the known time interval since closest
approach to Sgr A* to study the physics of stellar mass assembly in an extreme
environment as a function of absolute time.


title:
The Identification of 93 Day Periodic Photometric Variability for YSO
  YLW 16A

abstract:
  Periodic variability in young stellar objects (YSOs) offers indirect evidence
for an active dynamical mechanism. Starspots, accretion, stellar companions,
and disk veiling can contribute to the photometric variability of YSOs. As part
of an ongoing study of the Rho Oph star forming region, we report the discovery
of 92.6 day periodic variations for the Class I YSO YLW 16A, observed over a
period of three years. A SED model was fit to available photometric data for
the object. We propose a triple-system with an inner binary with a period of 93
days eclipsed by a warped circum-binary disk. The nature of the secondary is
unconstrained and could be stellar or sub-stellar. We report the discovery of a
tertiary companion at a projected separation of ~40 AU that could account for
the circum-binary disk warp. This light curve and model is similar to the model
we proposed for WL 4 in previous work. Understanding these systems may lead to
insights about the nature of stellar evolution and planetary formation, and
provide valuable benchmarks for future theoretical modeling and near- and
mid-infrared synoptic surveys of YSOs.


title:
Subaru Weak-Lensing Survey of Dark Matter Subhalos in the Coma Cluster :
  Subhalo Mass Function and Statistical Properties

abstract:
  We present a 4 deg^2 weak gravitational lensing survey of subhalos in the
very nearby Coma cluster using the Subaru/Suprime-Cam. The large apparent size
of cluster subhalos allows us to measure the mass of 32 subhalos detected in a
model-independent manner, down to the order of 10^-3 of the virial mass of the
cluster. Weak-lensing mass measurements of these shear-selected subhalos enable
us to investigate subhalo properties and the correlation between subhalo masses
and galaxy luminosities for the first time. The mean distortion profiles
stacked over subhalos show a sharply truncated feature which is well-fitted by
a Navarro-Frenk-White (NFW) mass model with the truncation radius, as expected
due to tidal destruction by the main cluster. We also found that subhalo
masses, truncation radii, and mass-to-light ratios decrease toward the cluster
center. The subhalo mass function, dn/dln M_sub, in the range of 2 orders of
magnitude in mass, is well described by a single power law or a Schechter
function. Best-fit power indices of 1.09_-0.32^+0.42 for the former model and
0.99_-0.23^+0.34 for the latter, are in remarkable agreement with slopes of
~0.9-1.0 predicted by the cold dark matter paradigm. The tangential distortion
signals in the radial range of 0.02-2Mpc/h from the cluster center show a
complex structure which is well described by a composition of three mass
components of subhalos, the NFW mass distribution as a smooth component of the
main cluster, and a lensing model from a large scale structure behind the
cluster. Although the lensing signals are 1 order of magnitude lower than those
for clusters at z~0.2, the total signal-to-noise ratio, S/N=13.3, is comparable
to, or higher, because the enormous number of background source galaxies
compensates for the low lensing efficiency of the low lensing efficiency of the
nearby cluster.


title: Locations of Peculiar Supernovae as a Diagnostic of Their Origins

abstract:
  We put constraints on the properties of the progenitors of peculiar
calcium-rich transients using the distribution of locations within their host
galaxies. We confirm that this class of transients do not follow the galaxy
stellar mass profile and are more likely to be found in remote locations of
their apparent hosts. We test the hypothesis that these transients are from low
metallicity progenitors by comparing their spatial distributions with the
predictions of self-consistent cosmological simulations that include star
formation and chemical enrichment. We find that while metal-poor stars and our
transient sample show a consistent preference for large offsets, metallicity
alone cannot explain the extreme cases. Invoking a lower age limit on the
progenitor helps to improve the match, indicating these events may result from
a very old metal-poor population. We also investigate the radial distribution
of globular cluster systems, and show that they too are consistent with the
class of calcium-rich transients. Because photometric upper limits exist for
globular clusters for some members of the class, a production mechanism related
to the dense environment of globular clusters is not favoured for the
calcium-rich events. However the methods developed in this paper may be used in
the future to constrain the effects of low metallicity on radially distant
core-collapse events or help establish a correlation with globular clusters for
other classes of peculiar explosions.


title:
RESLVE: Leveraging User Interest to Improve Entity Disambiguation on
  Short Text

abstract:
  We address the Named Entity Disambiguation (NED) problem for short,
user-generated texts on the social Web. In such settings, the lack of
linguistic features and sparse lexical context result in a high degree of
ambiguity and sharp performance drops of nearly 50% in the accuracy of
conventional NED systems. We handle these challenges by developing a model of
user-interest with respect to a personal knowledge context; and Wikipedia, a
particularly well-established and reliable knowledge base, is used to
instantiate the procedure. We conduct systematic evaluations using individuals'
posts from Twitter, YouTube, and Flickr and demonstrate that our novel
technique is able to achieve substantial performance gains beyond
state-of-the-art NED methods.


title:
On equilibration and coarsening in the quantum O(N) model at infinite
  $N$

abstract:
  The quantum O(N) model in the infinite $N$ limit is a paradigm for
symmetry-breaking. Qualitatively, its phase diagram is an excellent guide to
the equilibrium physics for more realistic values of $N$ in varying spatial
dimensions ($d>1$). Here we investigate the physics of this model out of
equilibrium, specifically its response to global quenches starting in the
disordered phase. If the model were to exhibit equilibration, the late time
state could be inferred from the finite temperature phase diagram. In the
infinite $N$ limit, we show that not only does the model not lead to
equilibration on account of an infinite number of conserved quantities, it also
does \emph{not} relax to a generalized Gibbs ensemble consistent with these
conserved quantities. Nevertheless, we \emph{still} find that the late time
states following quenches bear strong signatures of the equilibrium phase
diagram. Notably, we find that the model exhibits coarsening to a
non-equilibrium critical state only in dimensions $d>2$, that is, if the
equilibrium phase diagram contains an ordered phase at non-zero temperatures.


title:
Strong Asymmetric Surface Plasmon Polariton Emission by a Dipole Emitter
  near a Metal Surface

abstract:
  We show that the surface plasmon polariton (SPP) radiation patterns of
point-dipole emitters in the vicinity of a metal-dielectric interface are
generally asymmetric with respect to the location of the emitter. In particular
rotating dipoles, which emit elliptically polarized light, produce highly
asymmetric SPP radiation fields that include unidirectional emission.
Asymmetric SPP radiation patterns also result when a dipole oscillates tilted
with respect to the plane of the interface and optical losses or gains are
present in the materials. These effects can be used to directionally control
SPP emission and absorption, as well as to study emission and scattering
processes close to metal-dielectric interfaces. Possible implementations of
asymmetrically emitting SPP sources are discussed.


title:
DESPOTIC -- A New Software Library to Derive the Energetics and SPectra
  of Optically Thick Interstellar Clouds

abstract:
  I describe DESPOTIC, a code to Derive the Energetics and SPectra of Optically
Thick Interstellar Clouds. DESPOTIC represents such clouds using a one-zone
model, and can calculate line luminosities, line cooling rates, and in
restricted cases line profiles using an escape probability formalism. It also
includes approximate treatments of the dominant heating, cooling, and chemical
processes for the cold interstellar medium, including cosmic ray and X-ray
heating, grain photoelectric heating, heating of the dust by infrared and
ultraviolet radiation, thermal cooling of the dust, collisional energy exchange
between dust and gas, and a simple network for carbon chemistry. Based on these
heating, cooling, and chemical rates, DESPOTIC can calculate clouds'
equilibrium gas and dust temperatures, equilibrium carbon chemical state, and
time-dependent thermal and chemical evolution. The software is intended to
allow rapid and interactive calculation of clouds' characteristic temperatures,
identification of their dominant heating and cooling mechanisms, and prediction
of their observable spectra across a wide range of interstellar environments.
DESPOTIC is implemented as a Python package, and is released under the GNU
General Public License.


title:
DONUTS: A science frame autoguiding algorithm with sub-pixel precision,
  capable of guiding on defocused stars

abstract:
  We present the DONUTS autoguiding algorithm, designed to fix stellar
positions at the sub-pixel level for high-cadence time-series photometry, which
is also capable of autoguiding on defocused stars. DONUTS was designed to
calculate guide corrections from a series of science images and re-centre
telescope pointing between each exposure. The algorithm has the unique ability
of calculating guide corrections from under-sampled to heavily defocused point
spread functions. We present the case for why such an algorithm is important
for high precision photometry and give our results from off and on-sky testing.
We discuss the limitations of DONUTS and the facilities where it soon will be
deployed.


title: The Warm DM halo mass function below the cut-off scale

abstract:
  Warm Dark Matter (WDM) cosmologies are a viable alternative to the Cold Dark
Matter (CDM) scenario. Unfortunately, an accurate scrutiny of the WDM
predictions with N-body simulations has proven difficult due to numerical
artefacts. Here, we report on cosmological simulations that, for the first
time, are devoid of those problems, and thus, are able to accurately resolve
the WDM halo mass function well below the cut-off. We discover a complex
picture, with perturbations at different evolutionary stages populating
different ranges in the halo mass function. On the smallest mass scales we can
resolve, identified objects are typically centres of filaments that are
starting to collapse. On intermediate mass scales, objects typically correspond
to fluctuations that have collapsed and are in the process of relaxation,
whereas the high mass end is dominated by objects similar to haloes identified
in CDM simulations. We then explicitly show how the formation of low-mass
haloes is suppressed, which translates into a strong cut-off in the halo mass
function. This disfavours some analytic formulations that predict a halo mass
function that would extend well below the free streaming mass. We argue for a
more detailed exploration of the formation of the smallest structures expected
to form in a given cosmology, which, we foresee, will advance our overall
understanding of structure formation.


title:
Specific heat of the skyrmion lattice phase and field-induced
  tricritical point in MnSi

abstract:
  We report high-precision measurements of the temperature and magnetic field
dependence of the specific heat, C(T,H), across the magnetic phase diagram of
MnSi. Clear anomalies establish the skyrmion lattice unambiguously as a
thermodynamic phase. The evolution of the specific heat anomalies, the field
dependence of the entropy released at the phase transitions, and the
temperature versus field dependence of crossover lines provide striking
evidence of a tricritical point at an internal magnetic field of 340mT and
temperature of 28.5K. The existence of this tricritical point represents strong
support of a helimagnetic Brazovskii transition, i.e., a fluctuation-induced
first order transition at H = 0.


title: Astrophysical Coronae: Lessons from Modeling of the Intracluster Medium

abstract:
  Coronae exist in most astrophysical objects: stars, accretion disks, and
individual galaxies and clusters of galaxies. Coronae in these varied systems
have some common properties: 1) hydrostatic equilibrium in background gravity
is a good assumption; 2) they are optically thin, i.e., photons escape as soon
as they are born; 3) they have cooling times shorter than their ages, and thus
require heating for sustenance. Generally the coronal heating mechanisms are
quite complex but the structure of the corona is tightly constrained by the
interplay of cooling, {\em global} heating, and background gravity. We briefly
summarize the results from our studies of the intracluster medium (the cluster
corona) and draw inferences which should apply to most astrophysical coronae.


title: Comparison of GiBUU calculations with MiniBooNE pion production data

abstract:
  Background. Neutrino-induced pion production can give important informationon
the axial coupling to nucleon resonances. Furthermore, pion production
represents a major background to quasielastic-like events. Single pion
production data from the MiniBooNE in charged current neutrino scattering in
mineral oil appeared higher than expected within conventional theoretical
approaches.
  Purpose. We aim to investigate which model parameters affect the calculated
cross section and how they do this.
  Method. The Giessen Boltzmann--Uehling--Uhlenbeck (GiBUU) model is used for
an investigation of neutrino-nucleus reactions.
  Results. Presented are integrated and differential cross sections for 1\pi^+
and 1\pi^0 production before and after final state interactions in comparison
with the MiniBooNE data.
  Conclusions. For the MiniBooNE flux all processes (QE, 1\pi-background,
\Delta, higher resonance production, DIS) contribute to the observed final
state with one pion of a given charge. The uncertainty in elementary pion
production cross sections leads to a corresponding uncertainty in the nuclear
cross sections. Final state interactions change the shape of the muon-related
observables only slightly, but they significantly change the shape of pion
distributions.


title:
Preliminary estimation of the footprint and survivability of the
  Chelyabinsk Meteor fragments

abstract:
  There are several differences between the planetary entry of space vehicles
and that of asteroids. In this work we do investigate the applicability of
classical methods and approaches developed for debris analysis to asteroid
entry. In particular, the in-house DEBRIS tool, which has been designed and
developed to address the debris problem for uncontrolled re-entry objects, is
used here to predict the survivability and the ground footprint of asteroid
fragments. The results obtained for the Chelyabinsk event are presented as test
case. A comparison with the current available information is provided, proving
the validity of the proposed approach.


title:
Approximate NNLO Predictions for the Stop-Pair Production Cross Section
  at the LHC

abstract:
  If the minimal supersymmetric standard model at scales of around 1 TeV is
realized in nature, the total top-squark pair production cross section should
be measurable at the CERN Large Hadron Collider. In this work we present
precise predictions for this observable, which are based upon approximate NNLO
formulas obtained using soft-collinear effective theory methods.


title: On the satisfiability problem for a 3-level quantified syllogistic

abstract:
  We show that a collection of three-sorted set-theoretic formulae, denoted
TLQSR and which admits a restricted form of quantification over individual and
set variables, has a solvable satisfiability problem by proving that it enjoys
a small model property, i.e., any satisfiable TLQSR-formula psi has a finite
model whose size depends solely on the size of psi itself. We also introduce
the sublanguages (TLQSR)^h of TLQSR, whose formulae are characterized by having
quantifier prefixes of length bounded by h \geq 2 and some other syntactic
constraints, and we prove that each of them has the satisfiability problem
NP-complete. Then, we show that the modal logic S5 can be formalized in
(TLQSR)^3.


title: Multielectron High Harmonic Generation: simple man on a complex plane

abstract:
  From the famous classical "simple man" model to the recent multichannel model
for polyatomic molecules, this tutorial will guide you through the several
landmarks in our understanding of high harmonic generation and high harmonic
spectroscopy. Our goal was to provide recipes and insights for modelling the
harmonic response in various regimes, from the single active electron regime
typical for noble gas atoms to the laser-driven attosecond hole dynamics in
polyatomics. We have tried to pay particular attention to both simple recipes
and their limitations, including the connection of real-valued classical and
complex-valued quantum times and velocities. In addition to physical pictures,
general approaches and their practical realizations, we have also tried to
discuss some of the sticky technical issues, such as the possibility to
factorize high harmonic response into the three steps of ionization,
propagation and recombination and practical ways to treat strong field
ionization, search for the saddle points of multi-dimensional integrals, deal
with poles arising in the quantum-mechanical integrands, remove divergences
appearing in approximate saddle point expressions, etc.

categories: physics.atom-ph physics.chem-ph physics.optics quant-ph


title:
Stabilised finite element methods for non-symmetric, non-coercive and
  ill-posed problems. Part I: elliptic equations

abstract:
  In this paper we propose a new method to stabilise non-symmetric indefinite
problems. The idea is to solve a forward and an adjoint problem simultaneously
using a suitable stabilised finite element method. Both stabilisation of the
element residual and jumps of certain derivatives of the discrete solution over
element faces may be used. Under the assumption of well posedness of the
partial differential equation and its associated adjoint problem we prove
optimal error estimates in $H^1$ and $L^2$ norms in an abstract framework. Some
examples of problems that are neither symmetric nor coercive, but that enter
the abstract framework are given. First we treat indefinite
convection-diffusion equations, with non-solenoidal transport velocity and
either pure Dirichlet conditions or pure Neumann conditions and then a Cauchy
problem for the Helmholtz operator. Some numerical illustrations are given.


title: Monge-Ampere equation on exterior domains

abstract:
  We consider the Monge-Amp\`ere equation $\det(D^2u)=f$ where $f$ is a
positive function in $\mathbb R^n$ and $f=1+O(|x|^{-\beta})$ for some $\beta>2$
at infinity. If the equation is globally defined on $\mathbb R^n$ we classify
the asymptotic behavior of solutions at infinity. If the equation is defined
outside a convex bounded set we solve the corresponding exterior Dirichlet
problem. Finally we prove for $n\ge 3$ the existence of global solutions with
prescribed asymptotic behavior at infinity. The assumption $\beta>2$ is sharp
for all the results in this article.


title: Approximation algorithms for Euler genus and related problems

abstract:
  The Euler genus of a graph is a fundamental and well-studied parameter in
graph theory and topology. Computing it has been shown to be NP-hard by
[Thomassen '89 & '93], and it is known to be fixed-parameter tractable.
However, the approximability of the Euler genus is wide open. While the
existence of an O(1)-approximation is not ruled out, only an
O(sqrt(n))-approximation [Chen, Kanchi, Kanevsky '97] is known even in bounded
degree graphs. In this paper we give a polynomial-time algorithm which on input
a bounded-degree graph of Euler genus g, computes a drawing into a surface of
Euler genus poly(g, log(n)). Combined with the upper bound from [Chen, Kanchi,
Kanevsky '97], our result also implies a O(n^(1/2 - alpha))-approximation, for
some constant alpha>0.
  Using our algorithm for approximating the Euler genus as a subroutine, we
obtain, in a unified fashion, algorithms with approximation ratios of the form
poly(OPT, log(n)) for several related problems on bounded degree graphs. These
include the problems of orientable genus, crossing number, and planar edge and
vertex deletion problems. Our algorithm and proof of correctness for the
crossing number problem is simpler compared to the long and difficult proof in
the recent breakthrough by [Chuzhoy 2011], while essentially obtaining a
qualitatively similar result. For planar edge and vertex deletion problems our
results are the first to obtain a bound of form poly(OPT, log(n)).
  We also highlight some further applications of our results in the design of
algorithms for graphs with small genus. Many such algorithms require that a
drawing of the graph is given as part of the input. Our results imply that in
several interesting cases, we can implement such algorithms even when the
drawing is unknown.


title:
Closing Supersymmetric Resonance Regions With Direct Detection
  Experiments

abstract:
  In order for neutralino dark matter to avoid being overproduced in the early
universe, these particles must annihilate (or coannihilate) rather efficiently.
Neutralinos with sufficiently large couplings to annihilate at such high a rate
(such as those resulting from gaugino-higgsino mixing, as in "well-tempered" or
"focus point" scenarios), however, have become increasingly disfavored by the
null results of XENON100 and other direct detection experiments. One of the few
remaining ways that neutralinos could potentially evade such constraints is if
they annihilate through a resonance, as can occur if 2$m_{\chi^0}$ falls within
about $\sim$10% of either $m_{A/H}$, $m_h$, or $m_Z$. If no signal is observed
from upcoming direct detection experiments, the degree to which such a
resonance must be tuned will increase significantly. In this paper, we quantify
the degree to which such a resonance must be tuned in order to evade current
and projected constraints from direct detection experiments. Assuming a future
rate of progress among direct detection experiments that is similar to that
obtained over the past decade, we project that within 7 years the light Higgs
and $Z$ pole regions will be entirely closed, while the remaining parameter
space near the $A/H$ resonance will require that $2m_{\chi^0}$ be matched to
the central value (near $m_A$) to within less than 4%. At this rate of
progress, it will be a little over a decade before multi-ton direct detection
experiments will be able to close the remaining, highly-tuned, regions of the
$A/H$ resonance parameter space.


title: Mod\`ele flou d'expression des pr\'ef\'erences bas\'e sur les CP-Nets

abstract:
  This article addresses the problem of expressing preferences in flexible
queries while basing on a combination of the fuzzy logic theory and Conditional
Preference Networks or CP-Nets.


title:
Comment on "Physics considerations for laser-plasma linear colliders"
  and on "Beamstrahlung considerations in laser-plasma-accelerator-based linear
  colliders"

abstract:
  C. B. Schroeder, E. Esarey, C. Benedetti, and W. P. Leemans {Phys. Rev. ST
Accel. Beams 13, 101301 (2010) and 15, 051301 (2012)} have proposed a set of
parameters for a TeV-scale collider based on plasma wake field accelerator
principles. In particular, it is suggested that the luminosities greater than
10^34 cm-2s-1 are attainable for an electron-positron collider. In this comment
we dispute this set of parameters on the basis of first principles. The
interactions of accelerating beam with plasma impose fundamental limitations on
beam properties and, thus, on attainable luminosity values.


title: Symplectic fillings of Seifert fibered spaces

abstract:
  We give finiteness results and some classifications up to diffeomorphism of
minimal strong symplectic fillings of Seifert fibered spaces over S^2
satisfying certain conditions, with a fixed natural contact structure. In some
cases we can prove that all symplectic fillings are obtained by rational
blow-downs of a plumbing of spheres. In other cases, we produce new manifolds
with convex symplectic boundary, thus yielding new cut-and-paste operations on
symplectic manifolds containing certain configurations of symplectic spheres.


title:
Giant monopole energies from a constrained relativistic mean-field
  approach

abstract:
  Background: Average energies of nuclear collective modes may be efficiently
and accurately computed using a non-relativistic constrained approach without
reliance on a random phase approximation (RPA). Purpose: To extend the
constrained approach to the relativistic domain and to establish its impact on
the calibration of energy density functionals. Methods: Relativistic RPA
calculations are compared against the predictions of the corresponding
constrained approach using two accurately calibrated energy density
functionals. Results: We find excellent agreement-at the 2% level or
better-between the predictions of the relativistic RPA and the corresponding
constrained approach for magic (or semi-magic) nuclei ranging from 16O to
208Pb. Conclusions: An efficient and accurate method is proposed for
incorporating nuclear collective excitations into the calibration of future
energy density functionals.


title:
Homogenization for Rigid Suspensions with Random Velocity-Dependent
  Interfacial Forces

abstract:
  We study suspensions of solid particles in a viscous incompressible fluid in
the presence of highly oscillatory velocity-dependent surface forces. The flow
at a small Reynolds number is modeled by the Stokes equations coupled with the
motion of rigid particles arranged in a periodic array. The objective is to
perform homogenization for the given suspension and obtain an equivalent
description of a homogeneous (effective) medium, the macroscopic effect of the
interfacial forces and the effective viscosity are determined using the
analysis on a periodicity cell. In particular, the solutions $\bm{u}^\e_\omega$
to a family of problems corresponding to the size of microstructure $\e$ and
describing suspensions of rigid particles with random surface forces imposed on
the interface, converge $H^1$-- weakly as $\e \to 0$ a.s. to a solution of the
so-called homogenized problem with constant coefficients. It is also shown that
there is a corrector to a homogenized solution that yields a strong $H^1$--
convergence. The main technical construct is built upon the $\Gamma$--
convergence theory.


title:
The Higgs Particle: what is it, and why did it lead to a Nobel Prize in
  Physics?

abstract:
  Back in 1964, the theoretical physicists Francois Englert and Robert Brout,
as well as Peter Higgs, suggested an explanation for the fact that most
elementary particles - such as the electron - have a mass. This scenario
predicted a new particle, which has been observed experimentally only just now
at CERN (the European Organization for Nuclear Research). This discovery led to
the Physics Nobel Prize 2013. Here we sketch in simple terms the concept of the
Higgs mechanism, and its importance in particle physics.


title:
Ratios of $W$ and $Z$ cross sections at large boson $p_T$ as a
  constraint on PDFs and background to new physics

abstract:
  We motivate a measurement of various ratios of $W$ and $Z$ cross sections at
the Large Hadron Collider (LHC) at large values of the boson transverse
momentum ($p_T\gtrsim M_{W,Z}$). We study the dependence of predictions for
these cross-section ratios on the multiplicity of associated jets, the boson
$p_T$ and the LHC centre-of-mass energy. We present the flavour decomposition
of the initial-state partons and an evaluation of the theoretical
uncertainties. We show that the $W^+/W^-$ ratio is sensitive to the up-quark to
down-quark ratio of parton distribution functions (PDFs), while other
theoretical uncertainties are negligible, meaning that a precise measurement of
the $W^+/W^-$ ratio at large boson $p_T$ values could constrain the PDFs at
larger momentum fractions $x$ than the usual inclusive $W$ charge asymmetry.
The $W^\pm/Z$ ratio is insensitive to PDFs and most other theoretical
uncertainties, other than possibly electroweak corrections, and a precise
measurement will therefore be useful in validating theoretical predictions
needed in data-driven methods, such as using $W(\to\ell\nu)$+jets events to
estimate the $Z(\to\nu\bar{\nu})$+jets background in searches for new physics
at the LHC. The differential $W$ and $Z$ cross sections themselves, ${\rm
d}\sigma/{\rm d}p_T$, have the potential to constrain the gluon distribution,
provided that theoretical uncertainties from higher-order QCD and electroweak
corrections are brought under control, such as by inclusion of anticipated
next-to-next-to-leading order QCD corrections.


title: Non-additive dynamical Casimir atomic phases

abstract:
  We discuss a fundamental property of open quantum systems: the quantum phases
associated with their dynamical evolution are non-additive. We develop our
argument by considering a multiple-path atom interferometer in the vicinity of
a perfectly conducting plate. The coupling with the environment induces
dynamical corrections to the atomic phases. In the specific example of a
Casimir interaction, these corrections reflect the interplay between field
retardation effects and the external atomic motion. Non-local open-system
Casimir phase corrections are shown to be non-additive, which follows directly
from the unseparability of the influence functional describing the coupling of
the atomic waves to their environment. This is an unprecedented feature in atom
optics, which may be used in order to isolate non-local dynamical Casimir
phases from the standard quasi-static Casimir contributions.


title:
Liquid crystal-enabled electrophoresis of spheres in a nematic medium
  with negative dielectric anisotropy

abstract:
  We describe electrophoresis of spherical dielectric particles in a uniformly
aligned nematic medium with a negative dielectric anisotropy. A spherical
particle that orients the liquid crystal (LC) perpendicularly to its surface
moves under the application of the uniform direct current (DC) or alternating
current (AC) electric field. The electric field causes no distortions of the LC
director far away from the sphere. Electrophoresis in the nematic LC shows two
types of nonlinearity in the velocity vs. field dependence. The velocity
component parallel to the applied electric field grows linearly with the field,
but when the field is high enough, it also shows a cubic dependence. The most
interesting is the second type of nonlinear electrophoresis that causes the
sphere to move perpendicularly to the applied field. This perpendicular
component of velocity is proportional to the square of the field. The effect
exists only in a LC and disappears when the material is melted into an
isotropic fluid. The quadratic effect is caused by the dipolar symmetry of
director distortions around the sphere and is classified as an LC-enabled
electrophoresis (LCEEP). The nonlinear electrophoretic mobility of particles in
LCEEP offers a rich variety of control parameters to design 3D trajectories of
particles for microfluidic and optofluidic applications.


title:
The discovery of gamma-ray emission from Nova Sco 2012: An analysis
  using reprocessed Pass7 data

abstract:
  In March 2010 the Large Area Telescope (LAT) on-board the Fermi Gamma-ray
Space Telescope discovered for the first time >100 MeV gamma-ray emission from
a nova within our galaxy, V407 Cyg. The high-energy spectrum and light curve
was explained as a consequence of shock acceleration in the nova shell as it
interacts with the local ambient medium. It was suspected that the necessary
conditions for high-energy emission from novae would be rare. In June 2012 the
LAT detected a new flaring source, Fermi J1750-3243, that is spatially
coincident and contemporaneous with a new nova, Nova Sco 2012. We report on the
exciting discovery of this new 'gamma-ray' nova and present a detailed analysis
of its high-energy properties.


title:
Effects of alloying and strain on the magnetic properties of
  Fe$_{16}$N$_2$

abstract:
  The electronic structure and magnetic properties of pure and doped
{Fe$_{16}$N$_2$} systems have been studied in the local-density (LDA) and
quasiparticle self-consistent {\emph{GW}} approximations. The {\emph{GW}}
magnetic moment of pure {Fe$_{16}$N$_2$} is somewhat larger compared to LDA but
not anomalously large. The effects of doping on magnetic moment and exchange
coupling were analyzed using the coherent potential approximation. The
theoretical Curie temperature in pure {Fe$_{16}$N$_2$} is significantly higher
than the measured value, which is attributed to the quality of available
samples and the interpretation of experimental results. We found that different
Fe sites contribute very differently to the magnetocrystalline anisotropy
energy (MAE), which offers a way to increase MAE by small additions of Co or
Ti. MAE also increases under tetragonal strain.


title: Packing tree factors in random and pseudo-random graphs

abstract:
  For a fixed graph H with t vertices, an H-factor of a graph G with n
vertices, where t divides n, is a collection of vertex disjoint (not
necessarily induced) copies of H in G covering all vertices of G. We prove that
for a fixed tree T on t vertices and \epsilon > 0, the random graph G_{n,p},
with n a multiple of t, with high probability contains a family of
edge-disjoint T-factors covering all but an \epsilon-fraction of its edges, as
long as \epsilon^4 n p >> (log n)^2. Assuming stronger divisibility conditions,
the edge probability can be taken down to p > (C log n)/n. A similar packing
result is proved also for pseudo-random graphs, defined in terms of their
degrees and co-degrees.


title: Theory of charmless hadronic B-decays

abstract:
  I summarize results and performance of the dynamical theory of charmless
hadronic B decays, based on QCD factorization in the heavy quark limit. On the
theoretical side, a number of NNLO (alpha_s^2) amplitudes are now available,
all showing a well-behaved perturbative expansion. The large observed branching
fraction in B0 -> pi0 pi0 remains a challenge, implying either a large inverse
moment of the B-meson wave function or a sizable power correction (or
unexpected new physics). B-factory/Belle2 analyses of B -> gamma l nu may shed
light on this. On the other hand, the new Belle and LHCb measurements of
A_CP(pi^+ pi^-) bring the experimental result closer to QCDF predictions,
similar to what is found in B -> pi K decays, while S_pipi gives a competitive
gamma-determination. I remind the reader that for vector-vector final states, a
theoretical treatment of the full set of helicity amplitudes has existed and
met with some success since the B-factory era, and applies equally to LHCb
measurements of e.g. B_s -> phi phi.


title: Future Prospects at Electron-Positron Machines

abstract:
  This review will present the future prospects for physics at
electron-positron colliders running near the Upsilon(4S) as well as at the
charm and tau thresholds. It includes a review of the Belle II and SuperB
projects. Also reviewed are the plans for BES III, which operates near the
charm threshold at the IHEP BEPC machine in Bejing and the status of the Super
Charm/Tau Factory proposed for the Budker Institute for Nuclear Physics (BINP)
in Novosibirsk.


title: A note on two-sided ideals in locally C*-algebras

abstract:
  In the present note we show that if A is a locally C*-algebra, and I and J
are closed two-sided ideals in A, then the positive part of (I+J) is equal to
the sum of positive parts of I and J.


title: Gravitational waves from the sound of a first order phase transition

abstract:
  We report on the first 3-dimensional numerical simulations of first-order
phase transitions in the early universe to include the cosmic fluid as well as
the scalar field order parameter. We calculate the gravitational wave (GW)
spectrum resulting from the nucleation, expansion and collision of bubbles of
the low-temperature phase, for phase transition strengths and bubble wall
velocities covering many cases of interest. We find that the compression waves
in the fluid continue to be a source of GWs long after the bubbles have merged,
a new effect not taken properly into account in previous modelling of the GW
source. For a wide range of models the main source of the GWs produced by a
phase transition is therefore the sound the bubbles make.


title:
Antihydrogen $(\bar{\rm{H}})$ and muonic antihydrogen
  $(\bar{\rm{H}}_{\mu})$ formation in low energy three-charge-particle
  collisions

abstract:
  A few-body formalism is applied for computation of two different
three-charge-particle systems. The first system is a collision of a slow
antiproton, $\bar{\rm{p}}$, with a positronium atom: Ps$=(e^+e^-)$ $-$ a bound
state of an electron and a positron. The second problem is a collision of
$\bar{\rm{p}}$ with a muonic muonium atom, i.e. true muonium $-$ a bound state
of two muons one positive and one negative: Ps$_{\mu}=(\mu^+\mu^-)$. The total
cross section of the following two reactions: $\bar{\rm p}+(e^+e^-) \rightarrow
\bar{\rm{H}} + e^-$ and $\bar{\rm p}+(\mu^+\mu^-) \rightarrow
\bar{\rm{H}}_{\mu} + \mu^-$, where $\bar{\rm{H}}=(\bar{\rm p}e^+)$ is
antihydrogen and $\bar{\rm{H}}_{\mu}=(\bar{\rm p}\mu^+)$ is a muonic
antihydrogen atom, i.e. a bound state of $\bar{\rm{p}}$ and $\mu^+$, are
computed in the framework of a set of coupled two-component Faddeev-Hahn-type
(FH-type) equations. Unlike the original Faddeev approach the FH-type equations
are formulated in terms of only two but relevant components: $\Psi_1$ and
$\Psi_2$, of the system's three-body wave function $\Psi$, where
$\Psi=\Psi_1+\Psi_2$. In order to solve the FH-type equations $\Psi_1$ is
expanded in terms of the input channel target eigenfunctions, i.e. in this work
in terms of, for example, the $(\mu^+\mu^-)$ atom eigenfunctions. At the same
time $\Psi_2$ is expanded in terms of the output channel two-body wave
functions, that is in terms of $\bar{\rm{H}}_{\mu}$ atom eigenfunctions.


title: Riemann Hypothesis as an Uncertainty Relation

abstract:
  Physics is a fertile environment for trying to solve some number theory
problems. In particular, several tentative of linking the zeros of the
Riemann-zeta function with physical phenomena were reported. In this work, the
Riemann operator is introduced and used to transform the Riemann's hypothesis
in a Heisenberg-type uncertainty relation, offering a new way for studying the
zeros of Riemann's function


abstract:
  We show that $\mathbb{S}ol^3\times\mathbb{E}^1$-manifolds are Seifert fibred,
with general fibre the torus, and base one of the seven flat 2-orbifolds $T,
Kb, \mathbb{A}, \mathbb{M}b, S(2,2,2,2), P(2,2)$ or $\mathbb{D}(2,2)$, and
outline a classification of such 4-manifolds.


title:
Magnetodynamo Lifetimes for Rocky, Earth-Mass Exoplanets with
  Contrasting Mantle Convection Regimes

abstract:
  We used a thermal model of an iron core to calculate magnetodynamo evolution
in Earth-mass rocky planets to determine the sensitivity of dynamo lifetime and
intensity to planets with different mantle tectonic regimes, surface
temperatures, and core properties. The heat flow at the core-mantle boundary
(CMB) is derived from numerical models of mantle convection with a
viscous/pseudo-plastic rheology that captures the phenomenology of plate-like
tectonics. Our thermal evolution models predict a long-lived (~8 Gyr) field for
Earth and similar dynamo evolution for Earth-mass exoplanets with plate
tectonics. Both elevated surface temperature and pressure-dependent mantle
viscosity reduce the CMB heat flow but produce only slightly longer-lived
dynamos (~8-9.5 Gyr). Single-plate ("stagnant lid") planets with relatively low
CMB heat flow produce long-lived (~10.5 Gyr) dynamos. These weaker dynamos can
cease for several billions of years and subsequently reactivate due to the
additional entropy production associated with inner core growth, a possible
explanation for the absence of a magnetic field on present-day Venus. We also
show that dynamo operation is sensitive to the initial temperature, size, and
solidus of a planet's core. These dependencies would severely challenge any
attempt to distinguish exoplanets with plate tectonics and stagnant lids based
on the presence or absence of a magnetic field.


title:
Contrasting Elastic Properties of Heavily B- and N-doped Graphene, with
  Random Distributions Including Aggregates

abstract:
  We focused on elastic properties of B- and N-doped graphene in wide range of
concentrations up to 20%. The Young's, bulk and shear moduli and Poisson's
ratio have been calculated by means of the density functional theory for a
representative set of supercells with disordered impurity patterns including
aggregates. In contrast to earlier work, it is demonstrated that doping with
nitrogen even strengthens the graphene layers, whereas incorporation of boron
induces large structural and morphological changes seen in simulated STM
images. Young's and shear moduli increase or decrease with the doping strength
for nitrogen or boron, respectively, while bulk modulus and Poisson's ratio
exhibit opposite trends. Elastic properties of samples for both types of
impurities are strongly related to the electronic structures, especially for
heavy doping (>12%). Local arrangements of dopants and an agregation or
separation of impurities play crucial role in the determination of stiffness in
the investigated systems. Interestingly, these findings are opossed for B- and
N-contained samples.


title: Instability of Walker Propagating Domain Wall in Magnetic Nanowires

abstract:
  Stability of the well-known Walker propagating domain wall (DW) solution of
the Landau-Lifshitz-Gilbert equation is analytically investigated.
Surprisingly, the Walker's rigid body propagating DW mode is not stable against
the spin wave/wavepacket emission. In the low field region only stern spin
waves are emitted while both stern and bow waves are generated under high
fields. In a high enough field, but below the Walker breakdown field, the
Walker solution could be convective/absolute unstable if the transverse
magnetic anisotropy is larger than a critical value, corresponding to a
significant modification of the DW profile and DW propagating speed.


title:
The origin of the helicity hemispheric sign rule reversals in the
  mean-field solar-type dynamo

abstract:
  Observations of proxies of the magnetic helicity in the Sun over the past two
solar cycles revealed reversals of the helicity hemispheric sign rule (negative
in the North and positive in the South hemispheres). We apply the mean-field
solar dynamo model to study the reversals of the magnetic helicity sign for the
dynamo operating in the bulk of the solar convection zone. The evolution of the
magnetic helicity is governed by the conservation law. We found that the
reversal of the sign of the small-scale magnetic helicity follows the dynamo
wave propagating inside the convection zone. Therefore, the spatial patterns of
the magnetic helicity reversals reflect the processes which contribute to
generation and evolution of the large-scale magnetic fields. At the surface the
patterns of the helicity sign reversals are determined by the magnetic helicity
boundary conditions at the top of the convection zone. We demonstrate the
impact of fluctuations in the dynamo parameters and variability in dynamo cycle
amplitude on the reversals of the magnetic helicity sign rule. The obtained
results suggest that the magnetic helicity of the large-scale axisymmetric
field can be treated as an additional observational tracer for the solar
dynamo.


title:
A Schwarz lemma for harmonic mappings between the unit balls in real
  Euclidean spaces

abstract:
  In this paper we prove a Schwarz lemma for harmonic mappings between the unit
balls in real Euclidean spaces. Roughly speaking, our result says that under a
harmonic mapping between the unit balls in real Euclidean spaces, the image of
a smaller ball centered at origin can be controlled. This extends the related
result proved by Chen in complex plane.


title:
Viewing the Chemical Evolution of the Quark-Gluon Plasma with Charge
  Balance Functions

abstract:
  Correlations from charge conservation are affected by when charge/anticharge
pairs are created during the course of a relativistic heavy ion collision. For
charges created early, balancing charges are typically separated by the order
of one unit of spatial rapidity by the end of the collision, whereas those
charges produced later in the collision are far more correlated. By analyzing
correlations from STAR for different species, I show that one can distinguish
the two separate waves of charge creation expected in a high-energy collision,
one at early times when the QGP is formed and a second at hadronization.
Further, I extract the density of up, down and strange quarks at in the QGP and
find agreement at the 20% level with expectations for a chemically thermalized
plasma.


title:
Storage of electromagnetic waves in a metamaterial that mimics
  electromagnetically induced transparency

abstract:
  We propose a method for dynamically controlling the properties of a
metamaterial that mimics electromagnetically induced transparency (EIT) by
introducing varactor diodes to manipulate the structural symmetry of the
metamaterial. Dynamic modulation of the EIT property enables the storage and
retrieval of electromagnetic waves. We confirmed that the electromagnetic waves
were stored and released, while maintaining the phase distribution in the
propagating direction.


title: Common Information and Secret Key Capacity

abstract:
  We study the generation of a secret key of maximum rate by a pair of
terminals observing correlated sources and with the means to communicate over a
noiseless public com- munication channel. Our main result establishes a
structural equivalence between the generation of a maximum rate secret key and
the generation of a common randomness that renders the observations of the two
terminals conditionally independent. The minimum rate of such common
randomness, termed interactive common information, is related to Wyner's notion
of common information, and serves to characterize the minimum rate of
interactive public communication required to generate an optimum rate secret
key. This characterization yields a single-letter expression for the
aforementioned communication rate when the number of rounds of interaction are
bounded. An application of our results shows that interaction does not reduce
this rate for binary symmetric sources. Further, we provide an example for
which interaction does reduce the minimum rate of communication. Also, certain
invariance properties of common information quantities are established that may
be of independent interest.


title:
Stochastic Gravitational Wave Background generated by Cosmic String
  Networks: Velocity-Dependent One-Scale model versus Scale-Invariant Evolution

abstract:
  We compute the power spectrum of the stochastic gravitational wave background
generated by cosmic string networks described by the Velocity-Dependent
One-Scale (VOS) model, for a wide range of macroscopic and microscopic
parameters. The VOS model --- which has been shown to provide an accurate
macroscopic description of the evolution of cosmic string networks --- is used
to demonstrate that cosmic string networks are unable to rapidly attain
scale-invariant evolution after the transition between the radiation and matter
eras. However, in computations of the stochastic gravitational wave background,
it is often assumed that the networks experience scale-invariant evolution
throughout cosmological history. We demonstrate that this assumption leads to
an underestimation of the amplitude and broadness of the peak of the spectrum,
that may consequently lead to inaccurate observational constraints on the
cosmic string tension.


title:
Active control of magnetoresistance of organic spin valves using
  ferroelectricity

abstract:
  Organic spintronic devices have been appealing because of the long spin life
time of the charge carriers in the organic materials and their low cost,
flexibility and chemical diversity. In previous studies, the control of
resistance of organic spin valves is generally achieved by the alignment of the
magnetization directions of the two ferromagnetic electrodes, generating
magnetoresistance.1 Here we employ a new knob to tune the resistance of organic
spin valves by adding a thin ferroelectric interfacial layer between the
ferromagnetic electrode and the organic spacer. We show that the resistance can
be controlled by not only the spin alignment of the two ferromagnetic
electrodes, but also by the electric polarization of the interfacial
ferroelectric layer: the MR of the spin valve depends strongly on the history
of the bias voltage which is correlated with the polarization of the
ferroelectric layer; the MR even changes sign when the electric polarization of
the ferroelectric layer is reversed. This new tunability can be understood in
terms of the change of relative energy level alignment between ferromagnetic
electrode and the organic spacer caused by the electric dipole moment of the
ferroelectric layer. These findings enable active control of resistance using
both electric and magnetic fields, opening up possibility for multi-state
organic spin valves and shed light on the mechanism of the spin transport in
organic spin valves.


title: Equivalent conditions of Devaney chaos on the hyperspace

abstract:
  Let $T$ be a continuous self-map of a compact metric space $X$. The
transformation $T$ induces natural a continuous self-map $T_K$ on the
hyperspace $K(X)$ of all non-empty closed subsets of $X$. In this paper, we
show that the system $(K(X),T_K)$ on the hyperspace is Devaney chaotic if and
only if $(K(X),T_K)$ is an HY-system if and only if $(X,T)$ is an HY-system,
where a system $(Y,S)$ is called an HY-system if it is totally transitive and
has dense small periodic sets.


title: Maximum size binary matroids with no AG(3,2)-minor are graphic

abstract:
  We prove that the maximum size of a simple binary matroid of rank $r \geq 5$
with no AG(3,2)-minor is $\binom{r+1}{2}$ and characterise those matroids
achieving this bound. When $r \geq 6$, the graphic matroid $M(K_{r+1})$ is the
unique matroid meeting the bound, but there are a handful of smaller examples.
In addition, we determine the size function for non-regular simple binary
matroids with no AG(3,2)-minor and characterise the matroids of maximum size
for each rank.


title:
On nonlinear Schr\"odinger equations with random potentials: existence
  and probabilistic properties

abstract:
  In this paper we are concerned with nonlinear Schr\"odinger equations with
random potentials. Our class includes continuum and discrete potentials.
Conditions on the potential $V_{\omega}$ are found for existence of solutions
almost sure $\omega $. We study probabilistic properties like central limit
theorem and law of larger numbers for the obtained solutions by independent
ensembles. We also give estimates on the expected value for the
$L^{\infty}$-norm of the solution showing how it depends on the size of the
potential.


title: Frames in Krein spaces arising from a non-regular W-metric

abstract:
  A definition of frames in Krein spaces is stated and a complete
characterization is given by comparing them to frames in the associated Hilbert
space. The basic tools of frame theory are described in the formalism of Krein
spaces. It is shown how to transfer a frame for Hilbert spaces to Krein spaces
given by a W-metric, where the Gram operator W is not necessarily regular and
possibly unbounded.


title: Multihomogeneous Normed Algebras and Polynomial Identities

abstract:
  In this paper we consider PI-algebras $A$ over $\R$ or $\C$. It is well known
that in general such algebras are not normed algebras. In fact, there is a
nilpontent commutative algebra which is not a normed algebra, see [1]. Here we
address the question of whether it is possible to find a normed PI-algebra $B$
with the same polynomial identities as $A$, and moreover, whether there is some
Banach PI-algebra with this property. Our main theorem provides an affirmative
answer for this question and moreover we also show the existence of a Banach
Algebra with the same polynomial identities as $A$. As a byproduct we prove
that if $A$ is a normed PI-algebra and its completion is nil, then $A$ is
nilpotent. By introducing the concept of multihomogeneous norm we obtain as an
application of our main results that if $\FX$ is multihomogeneus normed algebra
and $A$ is a PI-algebra such that the completion of the quotient space
$\FX/Id(A)$ is nil, then $A$ is nilpotent. Both applications are extensions of
the study initiated in [4].


title: The Normed Ordered Cone of Operator Connections

abstract:
  A connection in Kubo-Ando sense is a binary operation for positive operators
on a Hilbert space satisfying the monotonicity, the transformer inequality and
the continuity from above. A mean is a connection $\sigma$ such that $A \sigma
A =A$ for all positive operators $A$. In this paper, we consider the interplay
between the cone of connections, the cone of operator monotone functions on
$\R^+$ and the cone of finite Borel measures on $[0,\infty]$. %We define a norm
for a connection in such a way that the set of operator connections becomes %a
normed ordered cone. %On the other hand, the cone of operator monotone
functions on $\R^+$ %and the cone of finite Borel measures on $[0,\infty]$ are
equipped with suitable norms. The set of operator connections is shown to be
isometrically order-isomorphic, as normed ordered cones, to the set of operator
monotone functions on $\R^+$. This set is isometrically isomorphic, as normed
cones, to the set of finite Borel measures on $[0,\infty]$. It follows that the
convergences of the sequence of connections, the sequence of their representing
functions and the sequence of their representing measures are equivalent. In
addition, we obtain characterizations for a connection to be a mean. In fact, a
connection is a mean if and only if it has norm 1.


title:
Dense optical and near-infrared monitoring of CTA 102 during high state
  in 2012 with OISTER: Detection of intra-night "orphan polarized flux flare"

abstract:
  CTA 102, classified as a flat spectrum radio quasar at z=1.037, produced
exceptionally bright optical flare in 2012 September. Following Fermi-LAT
detection of enhanced gamma-ray activity, we densely monitored this source in
the optical and near-infrared bands for the subsequent ten nights using twelve
telescopes in Japan and South-Africa. On MJD 56197 (2012 September 27, 4-5 days
after the peak of bright gamma-ray flare), polarized flux showed a transient
increase, while total flux and polarization angle remained almost constant
during the "orphan polarized-flux flare". We also detected an intra-night and
prominent flare on MJD 56202. The total and polarized fluxes showed quite
similar temporal variations, but PA again remained constant during the flare.
Interestingly, the polarization angles during the two flares were significantly
different from the jet direction. Emergence of a new emission component with
high polarization degree (PD) up to 40% would be responsible for the observed
two flares, and such a high PD indicates a presence of highly ordered magnetic
field at the emission site. We discuss that the well-ordered magnetic field and
even the observed directions of polarization angle which is grossly
perpendicular to the jet are reasonably accounted for by transverse shock(s)
propagating down the jet.


title:
Secure End-to-End Communication with Optimal Throughput in Unreliable
  Networks

abstract:
  We demonstrate the feasibility of end-to-end communication in highly
unreliable networks. Modeling a network as a graph with vertices representing
nodes and edges representing the links between them, we consider two forms of
unreliability: unpredictable edge-failures, and deliberate deviation from
protocol specifications by corrupt nodes.
  We present a robust routing protocol for end-to-end communication that is
simultaneously resilient to both forms of unreliability. In particular, we
prove rigorously that our protocol is SECURE against the actions of the corrupt
nodes, achieves correctness (Receiver gets ALL of the messages from Sender, in
order and without modification), and enjoys provably optimal throughput
performance, as measured using competitive analysis.
  Furthermore, our protocol does not incur any asymptotic memory overhead as
compared to other protocols that are unable to handle malicious interference of
corrupt nodes. In particular, our protocol requires O(n^2) memory per
processor, where n is the size of the network. This represents an O(n^2)
improvement over all existing protocols that have been designed for this
network model.


title:
Magnetic field induced dielectric relaxation in the strain glass state
  of Pr0.6Ca0.4MnO3

abstract:
  We present the dielectric and magnetodielectric properties of Pr0.6Ca0.4MnO3
polycrystalline sample. Dielectric permittivity ({\epsilon'}) (and
d{\epsilon'}/dT) portrays the charge order and other magnetic transitions
observed in the magnetization measurement. Dielectric study has revealed a
relaxation corresponding to ordering of polarons ~ 60 K that follows Arrhenius
behaviour both in the presence and absence of magnetic field and another
relaxation was noticed ~ 30 K only under a critical magnetic field (3.2 T) that
shows critical slow down of electronic charges obeying power law. Further, the
magnetic field induced relaxation shifts to low temperatures with the increase
of magnetic field. The observed field induced dielectric relaxation below the
reentered charge ordered state is linked with the rapid motions of boundaries
of the coexisting phases towards the martensite phase transformation.


title:
Edgeworth expansion for the integrated Levy driven Ornstein-Uhlenbeck
  process

abstract:
  We verify the Edgeworth expansion of any order for the integrated ergodic
Levy driven Ornstein-Uhlenbeck process, applying a Malliavin calculus with
truncation over the Wiener-Poisson space. Due to the special structure of the
model, the coefficients of the expansion can be given in a closed form.


title:
The optical photometric and spectroscopic investigation of Type IIP
  supernova 2012A

abstract:
  Supernova 2012A was discovered on 7.39UT, January, 2012 in the nearby galaxy
NGC 3239 at an unfiltered magnitude of 14.6 and classified spectroscopically as
a Type IIP event. Here, we present the optical photometric and spectroscopic
follow-up of the event during 14d to 130d post explosion.


title: On oriented graphs with minimal skew energy

abstract:
  Let $S(G^\sigma)$ be the skew-adjacency matrix of an oriented graph
$G^\sigma$. The skew energy of $G^\sigma$ is defined as the sum of all singular
values of its skew-adjacency matrix $S(G^\sigma)$. In this paper, we first
deduce an integral formula for the skew energy of an oriented graph. Then we
determine all oriented graphs with minimal skew energy among all connected
oriented graphs on $n$ vertices with $m \ (n\le m < 2(n-2))$ arcs, which is an
analogy to the conjecture for the energy of undirected graphs proposed by
Caporossi {\it et al.} [G. Caporossi, D. Cvetkovi$\acute{c}$, I. Gutman, P.
Hansen, Variable neighborhood search for extremal graphs. 2. Finding graphs
with external energy, J. Chem. Inf. Comput. Sci. 39 (1999) 984-996.]


title:
Back-action-free quantum optomechanics with negative-mass Bose-Einstein
  condensates

abstract:
  We propose that the dispersion management of coherent atomic matter waves can
be exploited to overcome quantum back-action in condensate-based optomechanical
sensors. The effective mass of an atomic Bose-Einstein condensate modulated by
an optical lattice can become negative, resulting in a negative-frequency
optomechanical oscillator, a negative environment temperature, and
optomechanical properties opposite to those of a positive-mass system. This
enables a quantum-mechanics-free subsystem insulated from quantum back-action.


title:
Estimation of relative efficiency of adaptive cluster vs traditional
  sampling designs applied to arrival of sharks

abstract:
  Adaptive Cluster Sampling (ACS) is introduced as a technique to use when
"natural" groupings are evident in a spatially distributed population,
especially sparsely distributed populations. An ACS sampling design will allow
efficient allocation of survey manpower with more effective decision rules for
where/when to allocate those resources. In particular, given a clustered
distribution, ACS would result in a lower variance of the mean estimator than
Simple Random Sampling (SRS). This paper derives a linear inequality based on a
ratio of variances and the SRS sample size to determine the conditions under
which ACS would be a more appropriate sampling strategy. This inequality could
be used to make preliminary decisions on the potential benefits of pursuing an
ACS design over an SRS design. The relationship between relative efficiency of
ACS over SRS is discussed for (1) variable conditions for neighborhood
expansion (Conditions to Adpat) (2) the degree of clustering and (3) the
percent of hits in a particular neighborhood. Simulation results demonstrate
how 'rare' clusters should be for ACS to be a better design than SRS. The
relationships that emerge from the simulation provide insights that were not
apparent in the analysis. The results are important in the estimation of
thresher shark landings along the California coast.


title: Multi-band optical light-curve behavior of core-collapse supernovae

abstract:
  We present survey results obtained from the UBVRI optical photometric
follow-up of 19 bright core-collapse SNe during 2002-2012 using 1-m class
optical telescopes operated by the Aryabhatta Research Institute of
Observational Science (acronym ARIES), Nainital India. This homogeneous set of
data have been used to study behavior of optical light/color curve, and to gain
insight into object-to-object peculiarity. We derive integrated luminosities
for types IIP, Ibc and luminous SNe. Two peculiar type IIP events having
photometric properties similar to normal IIP and spectroscopic properties
similar to sub-luminous IIP have been identified.


title:
Scattering theory of the hyperbolic BC(n) Sutherland and the rational
  BC(n) Ruijsenaars--Schneider--van Diejen models

abstract:
  In this paper, we investigate the scattering properties of the hyperbolic
BC(n) Sutherland and the rational BC(n) Ruijsenaars-Schneider-van Diejen
many-particle systems with three independent coupling constants. Utilizing the
recently established action-angle duality between these classical integrable
models, we construct their wave and scattering maps. In particular, we prove
that for both particle systems the scattering map has a factorized form.


title:
Real-world two-photon interference and proof-of-principle quantum key
  distribution immune to detector attacks

abstract:
  Several vulnerabilities of single photon detectors have recently been
exploited to compromise the security of quantum key distribution (QKD) systems.
In this letter we report the first proof-of-principle implementation of a new
quantum key distribution protocol that is immune to any such attack. More
precisely, we demonstrated this new approach to QKD in the laboratory over more
than 80 km of spooled fiber, as well as across different locations within the
city of Calgary. The robustness of our fibre-based implementation, together
with the enhanced level of security offered by the protocol, confirms QKD as a
realistic technology for safeguarding secrets in transmission. Furthermore, our
demonstration establishes the feasibility of controlled two-photon interference
in a real-world environment, and thereby removes a remaining obstacle to
realizing future applications of quantum communication, such as quantum
repeaters and, more generally, quantum networks.


title:
Photodissociation of carbon dioxide in singlet valence electronic
  states. I. Six multiply intersecting ab initio potential energy surfaces

abstract:
  The global potential energy surfaces of the first six singlet electronic
states of CO$_2$, 1---3$^1/!A'$ and 1---3$^1/!A"$ are constructed using high
level ab initio calculations. In linear molecule, they correspond to
$\tilde{X}^1\Sigma_g^+$, $1^1\Delta_u$, $1^1\Sigma_u^-$, and $1^1\Pi_g$. The
calculations accurately reproduce the known benchmarks for all states and
establish missing benchmarks for future calculations. The calculated states
strongly interact at avoided crossings and true intersections, both conical and
glancing. Near degeneracies can be found for each pair of six states and many
intersections involve more than two states. In particular, a fivefold
intersection dominates the Franck-Condon zone for the ultraviolet excitation
from the ground electronic state. The seam of this intersection traces out a
closed loop. All states are diabatized, and a diabatic $5\times 5$ potential
matrix is constructed, which can be used in quantum mechanical calculations of
the absorption spectrum of the five excited singlet valence states.


title:
Magnetocaloric effect and its implementation in critical behavior study
  of Mn4FeGe3-xSix intermetallic compounds

abstract:
  Magnetocaloric effect in Mn4FeGe3-xSix compounds has been studied by dc
magnetization measurements. For the parent compound Mn4FeGe3, the paramagnetic
to ferromagnetic transition temperature TC is above room temperature (320 K),
which initially remains constant for small Si substitution at the Ge site and
then decreases marginally with an increase in Si concentration. A large change
in magnetic entropy at the TC, under a magnetic field variation of 50 kOe, with
typical values of 5.9, 6.5, 5.9 and 4.4 J kg-1 K-1 for x = 0, 0.2, 0.6, and 1
samples, respectively, along with a broad operating temperature range and a
negligible hysteresis make Mn4FeGe3-xSix series a promising candidate for
magnetic refrigerant material around room temperature. Mn4FeGe3-xSix series is
found to undergo a second-order magnetic phase transition. The field dependence
of the magnetic entropy change has been brought out and implemented it to
deduce the critical exponents. The critical behavior study shows that the
magnetic interactions for x = 0 and 0.2 samples have two different behaviors
below and above TC. Below TC, it follows the mean field theory with long-range
magnetic interaction and above TC it follows the Heisenberg three-dimensional
model with short-range or local magnetic interaction. The magnetic exchange
interactions for the x = 0.6 and 1 samples follow the mean-field theory.


title:
Parameter estimation based on discrete observations of fractional
  Ornstein-Uhlenbeck process of the second kind

abstract:
  Fractional Ornstein-Uhlenbeck process of the second kind $(\text{fOU}_{2})$
is solution of the Langevin equation $\mathrm{d}X_t = -\theta
X_t\,\mathrm{d}t+\mathrm{d}Y_t^{(1)}, \ \theta >0$ with Gaussian driving noise
$ Y_t^{(1)} := \int^t_0 e^{-s} \,\mathrm{d}B_{a_s}$, where $ a_t= H
e^{\frac{t}{H}}$ and $B$ is a fractional Brownian motion with Hurst parameter
$H \in (0,1)$. In this article, we consider the case $H>\frac{1}{2}$. Then
using the ergodicity of $\text{fOU}_{2}$ process, we construct consistent
estimators of drift parameter $\theta$ based on discrete observations in two
possible cases: $(i)$ the Hurst parameter $H$ is known and $(ii)$ the Hurst
parameter $H$ is unknown. Moreover, using Malliavin calculus technique, we
prove central limit theorems for our estimators which is valid for the whole
range $H \in (\frac{1}{2},1)$.


title: Evolutionary Design of Digital Circuits Using Genetic Programming

abstract:
  For simple digital circuits, conventional method of designing circuits can
easily be applied. But for complex digital circuits, the conventional method of
designing circuits is not fruitfully applicable because it is time-consuming.
On the contrary, Genetic Programming is used mostly for automatic program
generation. The modern approach for designing Arithmetic circuits, commonly
digital circuits, is based on Graphs. This graph-based evolutionary design of
arithmetic circuits is a method of optimized designing of arithmetic circuits.
In this paper, a new technique for evolutionary design of digital circuits is
proposed using Genetic Programming (GP) with Subtree Mutation in place of
Graph-based design. The results obtained using this technique demonstrates the
potential capability of genetic programming in digital circuit design with
limited computer algorithms. The proposed technique, helps to simplify and
speed up the process of designing digital circuits, discovers a variation in
the field of digital circuit design where optimized digital circuits can be
successfully and effectively designed.


title:
WARN: an R package for quantitative reconstruction of weaning ages in
  archaeological populations using bone collagen nitrogen isotope ratios

abstract:
  Nitrogen isotope analysis of bone collagen has been used to reconstruct the
breastfeeding practices of archaeological human populations. However, weaning
ages have been estimated subjectively because of a lack of both information on
subadult bone collagen turnover rates and appropriate analytical models. Here,
we present a model for analyzing cross-sectional delta-15N data of subadult
bone collagen, which incorporates newly estimated bone collagen turnover rates
and a framework of approximate Bayesian computation. Temporal changes in human
subadult bone collagen turnover rates were estimated anew from data on
tissue-level bone metabolism reported in previous studies. A model for
reconstructing precise weaning ages was then developed and incorporating the
estimated turnover rates. The model is presented as a new open source R
package, WARN (Weaning Age Reconstruction with Nitrogen isotope analysis),
which computes the age at the start and end of weaning, 15N-enrichment through
maternal to infant tissue, and delta-15N value of collagen synthesized entirely
from weaning foods with their posterior probabilities. A precise reconstruction
of past breastfeeding and weaning practices over a wide range of time periods
and geographic regions could make it possible to understand this unique feature
of human life history and cultural diversity in infant feeding practices.


title:
Photodissociation of carbon dioxide in singlet valence electronic
  states. II. Five state absorption spectrum and vibronic assignment

abstract:
  The absorption spectrum of CO$_2$ in the wavelength range 120\,nm --- 160\,nm
is analyzed by means of quantum mechanical calculations performed using
vibronically coupled PESs of five singlet valence electronic states and the
coordinate dependent transition dipole moment vectors. The thermally averaged
spectrum, calculated for T=190\,K via Boltzmann averaging of optical
transitions from many initial rotational states, accurtely reproduces the
experimental spectral envelope, consisting of a low and a high energy band, the
positions of the absorption maxima, their FWHMs, peak intensities, and
frequencies of diffuse structures in each band. Contributions of the vibronic
interactions due to Renner-Teller coupling, conical intersections, and the
Herzberg-Teller effect are isolated and the calculated bands are assigned in
terms of adiabatic electronic states. Finally, diffuse structures in the
calculated bands are vibronically assigned using wave functions of the
underlying resonance states. It is demonstrated that the main progressions in
the high energy band correspond to consecutive excitations of the
pseudorotational motion along the closed loop of the CI seam, and progressions
differ in the number of nodes along the radial mode perpendicular to the closed
seam. Irregularity of the diffuse peaks in the low energy band is interpreted
as a manifestation of the carbene-type \'cyclic' OCO minimum.


title:
Interfacial Properties of Bilayer and Trilayer Graphene on Metal
  Substrates

abstract:
  One popular approach to prepare graphene is to grow them on transition metal
substrates via chemical vapor deposition. By using the density functional
theory with dispersion correction, we systematically investigate for the first
time the interfacial properties of bilayer (BLG) and trilayer graphene (TLG) on
metal substrates. Three categories of interfacial structures are revealed. The
adsorption of B(T)LG on Al, Ag, Cu, Au, and Pt substrates is a weak
physisorption, but a band gap can be opened. The adsorption of B(T)LG on Ti,
Ni, and Co substrates is a strong chemisorption, and a stacking-insensitive
band gap is opened for the two uncontacted layers of TLG. The adsorption of
B(T)LG on Pd substrate is a weaker chemisorption, with a band gap opened for
the uncontacted layers. This fundamental study also helps for B(T)LG device
study due to inevitable graphene/metal contact.


title:
Tunneling electron induced rotation of a copper phthalocyanine molecule
  on Cu(111)

abstract:
  The rates of a hindered molecular rotation induced by tunneling electrons are
evaluated using scattering theory within the sudden approximation. Our approach
explains the excitation of copper phthalocyanine molecules (CuPc) on Cu(111) as
revealed in a recent measurement of telegraph noise in a scanning tunneling
microscopy (STM) experiment [Schaffert \textit{et al.}, Nat. Mat. {\bf 12}, 223
(2013)]. A complete explanation of the experimental data is performed by
computing the geometry of the adsorbed system, its electronic structure and the
energy transfer between tunneling electrons and the molecule's rotational
degree of freedom. The results unambiguously show that tunneling electrons
induce a frustrated rotation of the molecule. In addition, the theory
determines the spatial distribution of the frustrated rotation excitation,
confirming the striking dominance of two out of four molecular lobes in the
observed excitation process. This lobe selectivity is attributed to the
different hybridizations with the underlying substrate.


title: Dualities for absolute zeta functions and multiple gamma functions

abstract:
  We study absolute zeta functions from the view point of a canonical
normalization. We introduce the absolute Hurwitz zeta function for the
normalization. In particular, we show that the theory of multiple gamma and
sine functions gives good normalizations in cases related to the Kurokawa
tensor product. In these cases, the functional equation of the absolute zeta
function turns out to be equivalent to the simplicity of the associated
non-classical multiple sine function of negative degree.


title: Smooth Transonic Flows in De Laval Nozzles

abstract:
  This paper concerns smooth transonic flows of Meyer type in finite de Laval
nozzles, which are governed by an equation of mixed type with degeneracy and
singularity at the sonic state. First we study the properties of sonic curves.
For any $C^2$ transonic flow of Meyer type, the set of exceptional points is
shown to be a closed line segment (may be empty or only one point).
Furthermore, it is proved that a flow with nonexceptional points is unstable
for a $C^1$ small perturbation in the shape of the nozzle. Then we seek smooth
transonic flows of Meyer type which satisfy physical boundary conditions and
whose sonic points are exceptional. For such a flow, its sonic curve must be
located at the throat of the nozzle and it is strongly singular in the sense
that the sonic curve is a characteristic degenerate boundary in the
subsonic-sonic region, while in the sonic-supersonic region all characteristics
from sonic points coincide, which are the sonic curve and never approach the
supersonic region. It is proved that there exists uniquely such a smooth
transonic flow near the throat of the nozzle, whose acceleration is Lipschitz
continuous, if the wall of the nozzle is sufficiently flat.


title: New optical telescope projects at Devasthal Observatory

abstract:
  Devasthal, located in the Kumaun region of Himalayas is emerging as one of
the best optical astronomy site in the continent. The minimum recorded ground
level atmospheric seeing at the site is 0.6 arcsec with median value at 1.1
arcsec. Currently, a 1.3-m fast (f/4) wide field-of-view (66 arcmin) optical
telescope is operating at the site. In near future, a 4-m liquid mirror
telescope in collaboration with Belgium and Canada, and a 3.6-m optical
telescope in collaboration with Belgium are expected to be installed in 2013.
The telescopes will be operated by Aryabhatta Research Institute of
Observational Sciences. The first instruments on the 3.6-m telescope will be
in-house designed and assembled faint object spectrograph and camera. The
second generation instruments will be including a large field-of-view optical
imager, high resolution optical spectrograph, integral field unit and an
optical near-infrared spectrograph. The 1.3-m telescope is primarily used for
wide field photometry imaging while the liquid mirror telescope will see a time
bound operation to image half a degree wide strip in the galactic plane. There
will be an aluminizing plant at the site to coat mirrors of sizes up to 3.7 m.
The Devasthal Observatory and its geographical importance in between major
astronomical observatories makes it important for time critical observations
requiring continuous monitoring of variable and transient objects from ground
based observatories. The site characteristics, its expansions plans and first
results from the existing telescope are presented.


title: Design and Development of a Heart Rate Measuring Device using Fingertip

abstract:
  In this paper, we presented the design and development of a new integrated
device for measuring heart rate using fingertip to improve estimating the heart
rate. As heart related diseases are increasing day by day, the need for an
accurate and affordable heart rate measuring device or heart monitor is
essential to ensure quality of health. However, most heart rate measuring tools
and environments are expensive and do not follow ergonomics. Our proposed Heart
Rate Measuring (HRM) device is economical and user friendly and uses optical
technology to detect the flow of blood through index finger. Three phases are
used to detect pulses on the fingertip that include pulse detection, signal
extraction, and pulse amplification. Qualitative and quantitative performance
evaluation of the device on real signals shows accuracy in heart rate
estimation, even under intense of physical activity. We compared the
performance of HRM device with Electrocardiogram reports and manual pulse
measurement of heartbeat of 90 human subjects of different ages. The results
showed that the error rate of the device is negligible.


title:
Corpus-based Web Document Summarization using Statistical and Linguistic
  Approach

abstract:
  Single document summarization generates summary by extracting the
representative sentences from the document. In this paper, we presented a novel
technique for summarization of domain-specific text from a single web document
that uses statistical and linguistic analysis on the text in a reference corpus
and the web document. The proposed summarizer uses the combinational function
of Sentence Weight (SW) and Subject Weight (SuW) to determine the rank of a
sentence, where SW is the function of number of terms (t_n) and number of words
(w_n) in a sentence, and term frequency (t_f) in the corpus and SuW is the
function of t_n and w_n in a subject, and t_f in the corpus. 30 percent of the
ranked sentences are considered to be the summary of the web document. We
generated three web document summaries using our technique and compared each of
them with the summaries developed manually from 16 different human subjects.
Results showed that 68 percent of the summaries produced by our approach
satisfy the manual summaries.


title: Sheaves of G-structures and generic G-models

abstract:
  In this article we give an equivariant version for the construction of
generic models on presheaves of structures. We deal with first order structures
endowed with a suitable action of some fixed group, say $G$; we call them
$G$-structures. We show that every exact presheaf of $G$-structures
$\mathcal{M}$ has a generic (equivariant) $G$-model $\mathcal{M}^{^{gen}}$.


title: Search for dark matter in compact hydrogen clouds

abstract:
  The recently published GALFA-HI Compact Cloud Catalogue lists 20 neutral
hydrogen clouds that might pinpoint previously undiscovered high-latitude dwarf
galaxies. Detection of an associated gamma-ray dark matter signal could provide
a route to distinguish unambiguously between truly dark matter dominated
systems that have accumulated neutral hydrogen but have not successfully
ignited star formation and pure gaseous structures devoid of dark matter. We
use 4.3 years of Fermi observations to derive gamma-ray flux upper limits in
the 1-300 GeV energy range for the sample. Limits on gamma rays from pair
annihilation of dark matter are also presented depending on the yet unknown
astrophysical factors.


title: Change-Point Detection under Dependence Based on Two-Sample U-Statistics

abstract:
  We study the detection of change-points in time series. The classical CUSUM
statistic for detection of jumps in the mean is known to be sensitive to
outliers. We thus propose a robust test based on the Wilcoxon two-sample test
statistic. The asymptotic distribution of this test can be derived from a
functional central limit theorem for two-sample U-statistics. We extend a
theorem of Csorgo and Horvath to the case of dependent data.


title:
Sound Absorption and Dispersion in Dilute Polyatomic Gases: A
  Generalized Kinetic Approach

abstract:
  A generalized kinetic model equation which takes into account the frequency
depence of the thermal conductivity is used to analyze the problem of sound
propagation in dilute polyatomic gases. By comparing the theoretical results
with some available experimental data we infer that our model equation provides
a precise transition between low and high-frequency limits.


title: Electrostatic interactions in concentrated protein solutions

abstract:
  We present an approximate method for calculating the electrostatic free
energy of concentrated protein solutions. Our method uses a cell model and
accounts for both the coulomb energy and the entropic cost of Donnan salt
partitioning. The former term is calculated by linearizing the
Poisson-Boltzmann equation around a nonzero average potential, while the second
term is calculated using a jellium approximation that is empirically modified
to reproduce the dilute solution limit. When combined with a short-ranged
binding interaction, calculated using the mean spherical approximation, our
model reproduces osmotic pressure measurements of bovine serum albumin
solutions. We also use our free energy to calculate the salt-dependent shift in
the critical temperature of lysozyme solutions and show why the predicted salt
partitioning between the dilute and dense phases has proven experimentally
elusive.


title: Nature of the vorticity in the G\"{o}del spacetime

abstract:
  The physical meaning of the vorticity of the matter content in G\"{o}del
spacetime is analyzed in some detail. As we shall see, unlike the situation in
general stationnary axially symmetric spacetimes (Lewis--Papapetrou), the
vorticity in G\"{o}del spacetime is not associated to a circular flow of
superenergy on the plane orthogonal to the vorticity vector. This fact might be
at the origin of the strange behaviour of gyroscopes in such spacetime. The
analysis emerging from the tilted version of G\"{o}del spacetime supports
further this point of view. In order to tell apart the two situations (with and
without circular flow of superenergy) we introduce two different definitions of
vorticity, related to the presence (absence) of such a flow.


title: Finite Difference Calculus for Alternating Permutations

abstract:
  The finite difference equation system introduced by Christiane Poupard in the
study of tangent trees is reinterpreted in the alternating permutation
environment. It makes it possible to make a joint study of both tangent and
secant trees and calculate the generating polynomial for alternating
permutations by a new statistic, referred to as being the greater neighbor of
the maximum.


title: Tree Calculus for Bivariable Difference Equations

abstract:
  Following Poupard's study of strictly ordered binary trees with respect to
two parameters, namely, "end of minimal chain" and "parent of maximum leaf" a
true Tree Calculus is being developed to solve a partial difference equation
system and then make a joint study of those two statistics. Their joint
distribution is shown to be symmetric and to be expressed in the form of an
explicit three-variable generating function.


title: Secant Tree Calculus

abstract:
  A true Tree Calculus is being developed to make a joint study of the two
statistics "eoc" (end of minimal chain) and "pom" (parent of maximum leaf) on
the set of secant trees. Their joint distribution restricted to the set
{eoc-pom<= 1} is shown to satisfy two partial difference equation systems, to
be symmetric and to be expressed in the form of an explicit three-variable
generating function.


title: Multivariable Tangent and Secant q-derivative Polynomials

abstract:
  The derivative polynomials introduced by Knuth and Buckholtz in their
calculations of the tangent and secant numbers are extended to a multivariable
$q$--environment. The $n$-th $q$-derivatives of the classical $q$-tangent and
$q$-secant are each given two polynomial expressions.
  The first polynomial expression is indexed by triples of integers, the second
by compositions of integers.
  The functional relation between those two classes is fully given by means of
combinatorial techniques. Moreover, those polynomials are proved to be
generating functions for so-called $t$-permutations by multivariable
statistics. By giving special values to those polynomials we recover classical
$q$-polynomials such as the Carlitz $q$-Eulerian polynomials and the
$(t,q)$-tangent and -secant analogs recently introduced. They also provide
$q$-analogs for the Springer numbers. Finally, the $t$-compositions used in
this paper furnish a combinatorial interpretation to one of the Fibonacci
triangles.


title:
Multicolor electrophotometry of the peculiar object V1357 Cyg=Cyg X-1 in
  the period 1986 -- 1992

abstract:
  \rm Observations of close binary system (CBS) V1357 Cyg=Cyg X-1 in the $WBVR$
bands are reported. Photometry was carried out at the telescopes located in
Kazakhstan, Uzbekistan and Crimea equipped with single-channel
$WBVR$-photometer with photon counting. 1358 individual observations in $WBVR$
bands on 202 nights were obtained.
  The analysis of the photometric data allows to conclude that different
photometric effects are superimposed on the orbital light curve of the system.
Among them are brightness declines, outbursts with different duration and
amplitude, chaotic variability, which sometimes exceeded the ellipsoidal
variability. Strong brightness decreases with magnitude $0^m.035 - 0^m.045$ are
observed, they are equal to the contribution of accretion disc to the total
luminosity of the system.
  10 years of photometric monitoring allowed to detect continous brightening of
the system, followed by luminosity decline (slow outburst). After the maximum
in 1994-96 the decline was equal to 7% in the $W$ band, 4% in the $V$ band, and
2% in the $V$ and $R$ bands.
  This paper continues the series of works on close systems with X-ray sources.
  \textbf{Key words}: Close binary systems - luminosity - ellipsoidal
variability - accretion disc


title: Log-Quadratic Bounds for the Gaussian Q-function

abstract:
  We present bounds of quadratic form for the logarithm of the Gaussian
Q-function. We also show an analytical method for deriving log-quadratic
approximations of the Q-function and give an approximation with absolute error
less than $10^{-3}$.


title: Binary Pulsars in Magnetic Field versus Spin Period Diagram

abstract:
  We analyzed 186 binary pulsars (BPSRs) in the magnetic field versus spin
period (B-P) diagram, where their relations to the millisecond pulsars (MSPs)
can be clearly shown. Generally, both BPSRs and MSPs are believed to be
recycled and spun-up in binary accreting phases, and evolved below the spin-up
line setting by the Eddington accretion rate ($\dot{M}{\bf \simeq}10^{18}
g/s$). It is noticed that most BPSRs are distributed around the spin-up line
with mass accretion rate $\dot{M}=10^{16} g/s$ and almost all MSP samples lie
above the spin-up line with $\dot{M}\sim10^{15} g/s$. Thus, we calculate that a
minimum accretion rate ($\dot{M}\sim 10^{15} g/s$) is required for the MSP
formation, and physical reasons for this are proposed. In the B-P diagram, the
positions of BPSRs and their relations to the binary parameters, such as the
companion mass, orbital period and eccentricity, are illustrated and discussed.
In addition, for the seven BPSRs located above the limit spin-up line, possible
causes are suggested.


title: Kernel Reconstruction ICA for Sparse Representation

abstract:
  Independent Component Analysis (ICA) is an effective unsupervised tool to
learn statistically independent representation. However, ICA is not only
sensitive to whitening but also difficult to learn an over-complete basis.
Consequently, ICA with soft Reconstruction cost(RICA) was presented to learn
sparse representations with over-complete basis even on unwhitened data.
Whereas RICA is infeasible to represent the data with nonlinear structure due
to its intrinsic linearity. In addition, RICA is essentially an unsupervised
method and can not utilize the class information. In this paper, we propose a
kernel ICA model with reconstruction constraint (kRICA) to capture the
nonlinear features. To bring in the class information, we further extend the
unsupervised kRICA to a supervised one by introducing a discrimination
constraint, namely d-kRICA. This constraint leads to learn a structured basis
consisted of basis vectors from different basis subsets corresponding to
different class labels. Then each subset will sparsely represent well for its
own class but not for the others. Furthermore, data samples belonging to the
same class will have similar representations, and thereby the learned sparse
representations can take more discriminative power. Experimental results
validate the effectiveness of kRICA and d-kRICA for image classification.


title:
Measurement of collisions between rubidium atoms and optically dark
  rubidium ions

abstract:
  We measure the collision rate coefficient between laser cooled Rubidium (Rb)
atoms in a magneto-optical trap (MOT) and optically dark Rb+ ions in an
overlapping Paul trap. In such a mixture, the ions are created from the MOT
atoms and allowed to accumulate in the ion trap, which results in a significant
reduction in the number of steady state MOT atoms. A theoretical rate equation
model is developed to describe the evolution of the MOT atom number, due to
ionization and ion-atom collision, and derive an expression for the ion-atom
collision rate coefficient. The loss of MOT atoms is studied systematically, by
sequentially switching on the various mechanisms in the experiment. Combining
the measurements with the model allows the direct determination of the ion-atom
collision rate coefficient. Finally the scope of the experimental technique
developed here is discussed.


title:
Spectroscopic observations of the interacting massive binary
  AQ\,Cassiopea

abstract:
  New spectroscopic observations of the double-lined eclipsing binary AQ\,Cas
are presented. All available spectroscopic and photometric observations have
been analysed for the fundamental properties of the components. Analyses show
that the system consists of a massive primary with a mass of 17.63$\pm$0.91
M$_{\odot}$ and radius of 13.48$\pm$0.64R$_{\odot}$ and a secondary with
12.56$\pm$0.81 M$_{\odot}$ and radius of 23.55$\pm$0.73 R$_{\odot}$,
corresponding spectral types of B0.5($\pm$2) II-III + B3($\pm$1) II. The
secondary star fills its corresponding Roche lobe and mass transfer to the
primary star is going on. This stream considerably does affect the photometric
observations both starting from the second quarter up to the first contact of
primary eclipse and just at the second maximum. Thus, the light curve is
distorted and tightly depended on the wavelength of the observations. The
available multi passband light curves have been analysed by taking the stream
effects, as either hot or cool spots, into account. The comparison of the
models and observations in the $\log(L/L_{\odot})$ - $\log T_{eff}$ and $\log g
- \log T_{eff}$ diagrams clearly shows that the more massive star is consistent
with models and is predicted to be close to the phase of hydrogen shell
ignition. Average distance to the system is estimated as 4150$\pm$240 pc using
the BVJHK magnitudes and V-passband extinction.


title: Over saturation behavior of SiPMs at high photon exposure

abstract:
  Several types of Silicon Photomultipliers were exposed to short pulsed laser
light (~ 30 ps FWHM) with its intensity varying from single photon to well
above the number of microcells of the device. We observed a significant
deviation of the output of SiPMs from the expected behavior although such
response curve is considered to be rather trivial. We also noticed that the
output exceeds the maximum expected pulse height, which should be defined as
the total number of pixels times the single photon pulse height. At the highest
light intensity (~ 500 times the number of pixels) that we tested, the signal
output reached up to twice the maximum theoretical pulse height, and still did
not fully saturate.


title:
Spectroscopic characterization of graphene films grown on Pt (111)
  surface by chemical vapor deposition of ethylene

abstract:
  This work reports the peculiar properties of a graphene film prepared by the
chemical vapor deposition (CVD) of ethylene in high vacuum on a well oriented
and carefully cleaned Pt(111) crystal surface maintained at high temperature.
In-situ and ex-situ characterization techniques (low energy electron
diffraction, high resolution electron energy loss spectroscopy, scanning
electron microscopy and Raman micro-spectroscopy) used here indicate the
prevalence of single layer regions and the presence of two different
orientations of the graphene sheets with respect to the Pt(111) substrate. In
most of the deposited area evidence is found of a compressive stress for the
graphene lattice, as a net result of the growth process on a metal substrate.
This graphene film grown on Pt(111) exhibits a lower degree of order and of
homogeneity with respect to the exfoliated graphene on Si/SiO2, as it is found
generally for graphene on metals, but several characterization techniques
indicates a better quality than in previous deposition experiments on the same
metal substrate.