title:
SSSC-AM: A Unified Framework for Video Co-Segmentation by Structured
  Sparse Subspace Clustering with Appearance and Motion Features

abstract:
  Video co-segmentation refers to the task of jointly segmenting common objects
appearing in a given group of videos. In practice, high-dimensional data such
as videos can be conceptually thought as being drawn from a union of subspaces
corresponding to categories rather than from a smooth manifold. Therefore,
segmenting data into respective subspaces --- subspace clustering --- finds
widespread applications in computer vision, including co-segmentation.
State-of-the-art methods via subspace clustering seek to solve the problem in
two steps:
  First, an affinity matrix is built from data, with appearance features or
motion patterns. Second, the data are segmented by applying spectral clustering
to the affinity matrix. However, this process is insufficient to obtain an
optimal solution since it does not take into account the {\em interdependence}
of the affinity matrix with the segmentation. In this work, we present a novel
unified video co-segmentation framework inspired by the recent Structured
Sparse Subspace Clustering ($\mathrm{S^{3}C}$) based on the {\em
self-expressiveness} model. Our method yields more consistent segmentation
results. In order to improve the detectability of motion features with missing
trajectories due to occlusion or tracked points moving out of frames, we add an
extra-dimensional signature to the motion trajectories. Moreover, we
reformulate the $\mathrm{S^{3}C}$ algorithm by adding the affine subspace
constraint in order to make it more suitable to segment rigid motions lying in
affine subspaces of dimension at most $3$. Our experiments on MOViCS dataset
show that our framework achieves the highest overall performance among baseline
algorithms and demonstrate its robustness to heavy noise.


title: Identifiability of restricted latent class models with binary responses

abstract:
  Statistical latent class models are widely used in social and psychological
researches, yet it is often difficult to establish the identifiability of the
model parameters. In this paper we consider the identifiability issue of a
family of restricted latent class models, where the restriction structures are
needed to reflect pre-specified assumptions on the related assessment. We
establish the identifiability results in the strict sense and specify which
types of restriction structure would give the identifiability of the model
parameters. The results not only guarantee the validity of many of the
popularly used models, but also provide a guideline for the related
experimental design, where in the current applications the design is usually
experience based and identifiability is not guaranteed. Theoretically, we
develop a new technique to establish the identifiability result, which may be
extended to other restricted latent class models.


title:
Stochastic self-consistent Green's function second-order perturbation
  theory (sGF2)

abstract:
  The second-order Green's function method (GF2) was shown recently to be an
accurate self-consistent approach for electronic structure of correlated
systems since the self-energy accounts for both the weak and some of the strong
correlation. The numerical scaling of GF2 is quite steep however, $O({N^5})$
(where the pre-factor is often hundreds), effectively preventing its
application to large systems. Here, we develop a stochastic approach to GF2
(sGF2) where the self-energy is evaluated by a random-vector decomposition of
Green's functions so that the dominant part of the calculation scales quasi
linearly with system size. A study of hydrogen chains shows that the resulting
approach is numerically efficient and accurate, as the stochastic errors are
very small, 0.05% of the correlation energy for large systems with only a
moderate computational effort. The method also yields automatically efficient
MP2 energies and is automatically temperature dependent.

categories: physics.chem-ph cond-mat.mes-hall cond-mat.mtrl-sci physics.comp-ph


title: Turbo-Equalization Using Partial Gaussian Approximation

abstract:
  This paper deals with turbo-equalization for coded data transmission over
intersymbol interference (ISI) channels. We propose a message-passing algorithm
that uses the expectation-propagation rule to convert messages passed from the
demodulator-decoder to the equalizer and computes messages returned by the
equalizer by using a partial Gaussian approximation (PGA). Results from Monte
Carlo simulations show that this approach leads to a significant performance
improvement compared to state-of-the-art turbo-equalizers and allows for
trading performance with complexity. We exploit the specific structure of the
ISI channel model to significantly reduce the complexity of the PGA compared to
that considered in the initial paper proposing the method.


title: Pulse-compression ghost imaging lidar via coherent detection

abstract:
  Ghost imaging (GI) lidar, as a novel remote sensing technique,has been
receiving increasing interest in recent years. By combining pulse-compression
technique and coherent detection with GI, we propose a new lidar system called
pulse-compression GI lidar. Our analytical results, which are backed up by
numerical simulations, demonstrate that pulse-compression GI lidar can obtain
the target's spatial intensity distribution, range and moving velocity.
Compared with conventional pulsed GI lidar system, pulse-compression GI lidar,
without decreasing the range resolution, is easy to obtain high single pulse
energy with the use of a long pulse, and the mechanism of coherent detection
can eliminate the influence of the stray light, which can dramatically improve
the detection sensitivity and detection range.


title: Macroscopic detection of deformed QM by the harmonic oscillator

abstract:
  Based on the nonperturbative analysis, we show that the classical motion of
harmonic oscillator derived from the deformed QM is manifestly in contradiction
with observations. For this reason, we take an alternate way for estimating the
effect and discuss its possible observational manifestations in macrophysics.


title: On analogues of Arakawa-Kaneko zeta functions of Mordell-Tornheim type

abstract:
  In this paper, we construct certain analogues of the Arakawa-Kaneko zeta
functions. We prove functional relations between these functions and the
Mordell-Tornheim multiple zeta functions. Furthermore we give some formulas
among Mordell-Tornheim multiple zeta values as their applications.


title: Saliency Detection for Improving Object Proposals

abstract:
  Object proposals greatly benefit object detection task in recent
state-of-the-art works. However, the existing object proposals usually have low
localization accuracy at high intersection over union threshold. To address it,
we apply saliency detection to each bounding box to improve their quality in
this paper. We first present a geodesic saliency detection method in contour,
which is designed to find closed contours. Then, we apply it to each candidate
box with multi-sizes, and refined boxes can be easily produced in the obtained
saliency maps which are further used to calculate saliency scores for proposal
ranking. Experiments on PASCAL VOC 2007 test dataset demonstrate the proposed
refinement approach can greatly improve existing models.


title:
All-electrical generation and control of odd-frequency s-wave Cooper
  pairs in double quantum dots

abstract:
  We propose an all-electrical experimental setup to detect and manipulate the
amplitude of odd-frequency pairing in a double quantum dot. Odd-frequency pair
amplitude is induced from the breakdown of orbital symmetry when Cooper pairs
are injected in the double dot with electrons in different dots. When the dot
levels are aligned with the Fermi energy, i.e., on resonance, nonlocal Andreev
processes are directly connected to the presence of odd-frequency pairing.
Therefore, their amplitude can be manipulated by tuning the level positions.
Detection of nonlocal Andreev processes by conductance measurements contributes
a direct proof of the existence of odd-frequency pair amplitude and is
available using current experimental techniques.


title:
The Liouville theorem and the $L^2$ decay of the FENE dumbbell model of
  polymeric flows

abstract:
  In this paper we mainly investigate the finite extensible nonlinear elastic
(FENE) dumbbell model with dimension $d\geq2$ in the whole space. We first
proved that there is only the trivial solution for the steady-state FENE model
under some integrable condition. Our obtained results generalize and cover the
classical results to the stationary Navier-Stokes equations. Then, we study
about the $L^2$ decay of the co-rotation FENE model. Concretely, the $L^2$
decay rate of the velocity is $(1+t)^{-\frac{d}{4}}$ when $d\geq3$, and
$\ln^{-k}{(e+t)}, k\in \mathds{N}^{+}$ when $d=2$. This result improves
considerably the recent result of \cite{Schonbek2} by Schonbek. Moreover, the
decay of general FENE model has been considered.


title:
Lifshitz scaling effects on holographic paramagnetism/ferromagneism
  phase transition

abstract:
  In the probe limit, we investigate holographic paramagnetism-ferromagnetism
phase transition in the four-dimensional (4D) and five-dimensional(5D) Lifshitz
black holes by means of numerical and semi-analytical methods, which is
realized by introducing a massive 2-form field coupled to the Maxwell field. We
find that the Lifshitz dynamical exponent $z$ contributes evidently to magnetic
moment and hysteresis loop of single magnetic domain quantitatively not
qualitatively. Concretely, in the case without external magnetic field, the
spontaneous magnetization and ferromagnetic phase transition happen when the
temperature gets low enough, and the critical exponent for the magnetic moment
is always $1/2$, which is in agreement with the result from mean field theory.
And the increasing $z$ enhances the phase transition and increases the DC
resistivity which behaves as the colossal magnetic resistance effect in some
materials. Furthermore, in the presence of the external magnetic field, the
magnetic susceptibility satisfies the Cure-Weiss law with a general $z$. But
the increase of $z$ will result in shortening the period of the external
magnetic field.


title:
Regression-based Hypergraph Learning for Image Clustering and
  Classification

abstract:
  Inspired by the recently remarkable successes of Sparse Representation (SR),
Collaborative Representation (CR) and sparse graph, we present a novel
hypergraph model named Regression-based Hypergraph (RH) which utilizes the
regression models to construct the high quality hypergraphs. Moreover, we plug
RH into two conventional hypergraph learning frameworks, namely hypergraph
spectral clustering and hypergraph transduction, to present Regression-based
Hypergraph Spectral Clustering (RHSC) and Regression-based Hypergraph
Transduction (RHT) models for addressing the image clustering and
classification issues. Sparse Representation and Collaborative Representation
are employed to instantiate two RH instances and their RHSC and RHT algorithms.
The experimental results on six popular image databases demonstrate that the
proposed RH learning algorithms achieve promising image clustering and
classification performances, and also validate that RH can inherit the
desirable properties from both hypergraph models and regression models.


title: The Cauchy interlace theorem for symmetrizable matrices

abstract:
  Symmetrizable matrices are those which are symmetric when multiplied by a
diagonal matrix with positive entries. The Cauchy interlace theorem states that
the eigenvalues of a real symmetric matrix interlace with those of any
principal submatrix (obtained by deleting a row-column pair of the original
matrix). In this paper we extend the Cauchy interlace theorem for symmetric
matrices to this large class, called symmetrizable matrices. This extension is
interesting by the fact that in the symmetric case, the Cauchy interlace
theorem together with the Courant-Fischer minimax theorem and Sylvester's law
of inertia, each one can be proven from the others and thus they are
essentially equivalent. The first two theorems have important applications in
the singular value and eigenvalue decompositions, the third is useful in the
development and analysis of algorithms for the symmetric eigenvalue problem.
Consequently various and several applications whom are contingent on the
symmetric condition may occur for this large class of not necessary symmetric
matrices and open the door for many applications in future studies. We note
that our techniques are based on the celebrated Dodgson's identity.


title:
Alignments of dark matter halos with large-scale tidal fields: mass and
  redshift dependence

abstract:
  Large scale tidal field estimated directly from the distribution of dark
matter halos is used to investigate how halo shapes and spin vectors are
aligned with the cosmic web. The major, intermediate and minor axes of halos
are aligned with the corresponding tidal axes, and halo spin axes tend to be
parallel with the intermediate axes and perpendicular to the major axes of
tidal field. The strengths of these alignments generally increase with halo
mass and redshift, but the dependencies are only through the peak height,
{\nu}. The scaling relations of the alignment strengths with the value of {\nu}
indicate that the alignment strengths remain roughly constant when the
structures within which the halos reside are still in quasi-linear regime, but
decreases as nonlinear evolution becomes more important. We also calculate the
alignments in projection so that our results can be compared directly with
observations. Finally, we investigate the alignments of tidal tensors on large
scales, and use the results to understand alignments of halo pairs separated at
various distances. Our results suggest coherent structure of the tidal field is
the underlying reason for the alignments of halos and galaxies seen in
numerical simulations and in observations.


title:
Top-$K$ Ranking from Pairwise Comparisons: When Spectral Ranking is
  Optimal

abstract:
  We explore the top-$K$ rank aggregation problem. Suppose a collection of
items is compared in pairs repeatedly, and we aim to recover a consistent
ordering that focuses on the top-$K$ ranked items based on partially revealed
preference information. We investigate the Bradley-Terry-Luce model in which
one ranks items according to their perceived utilities modeled as noisy
observations of their underlying true utilities. Our main contributions are
two-fold. First, in a general comparison model where item pairs to compare are
given a priori, we attain an upper and lower bound on the sample size for
reliable recovery of the top-$K$ ranked items. Second, more importantly,
extending the result to a random comparison model where item pairs to compare
are chosen independently with some probability, we show that in slightly
restricted regimes, the gap between the derived bounds reduces to a constant
factor, hence reveals that a spectral method can achieve the minimax optimality
on the (order-wise) sample size required for top-$K$ ranking. That is to say,
we demonstrate a spectral method alone to be sufficient to achieve the
optimality and advantageous in terms of computational complexity, as it does
not require an additional stage of maximum likelihood estimation that a
state-of-the-art scheme employs to achieve the optimality. We corroborate our
main results by numerical experiments.


title:
Impacts of Network Topology on the Performance of a Distributed
  Algorithm Solving Linear Equations

abstract:
  Recently a distributed algorithm has been proposed for multi-agent networks
to solve a system of linear algebraic equations, by assuming each agent only
knows part of the system and is able to communicate with nearest neighbors to
update their local solutions. This paper investigates how the network topology
impacts exponential convergence of the proposed algorithm. It is found that
networks with higher mean degree, smaller diameter, and homogeneous degree
distribution tend to achieve faster convergence. Both analytical and numerical
results are provided.


title:
Melting the Superconducting State in the Electron Doped Cuprate
  Pr$_{1.85}% $Ce$_{0.15}$CuO$_{4-\delta}$ with Intense near-infrared and
  Terahertz Pulses

abstract:
  We studied the superconducting (SC) state depletion process in an electron
doped cuprate Pr$_{1.85}$Ce$_{0.15}$CuO$_{4-\delta}$ by pumping with
near-infrared (NIR) and narrow-band THz pulses. When pumping with THz pulses
tuned just above the SC gap, we find the absorbed energy density required to
deplete superconductivity, $A_{dep}$, matches the thermodynamic condensation
energy. Contrary, by NIR pumping $A_{dep}$ is an order of magnitude higher,
despite the fact that the SC gap is much smaller than the energy of relevant
bosonic excitations. The result implies that only a small subset of bosons
contribute to pairing.


title:
Recommendations on presenting LHC searches for missing transverse energy
  signals using simplified $s$-channel models of dark matter

abstract:
  This document summarises the proposal of the LHC Dark Matter Working Group on
how to present LHC results on $s$-channel simplified dark matter models and to
compare them to direct (indirect) detection experiments.


title:
Ab-initio electron scattering cross-sections and transport in liquid
  xenon

abstract:
  Ab-initio electron - liquid phase xenon fully differential cross-sections for
electrons scattering in liquid xenon are developed from a solution of the
Dirac-Fock scattering equations, using a recently developed framework [1] which
considers multipole polarizabilities, a non-local treatment of exchange, and
screening and coherent scattering effects. A multi-term solution of Boltzmann's
equation accounting for the full anisotropic nature of the differential
cross-section is used to calculate transport properties of excess electrons in
liquid xenon. The results were found to agree to within 25% of the measured
mobilities and characteristic energies over the reduced field range of 10^{-4}
to 1 Td. The accuracies are comparable to those achieved in the gas phase. A
simple model, informed by highly accurate gas-phase cross-sections, is
presented to transform highly accurate gas-phase cross-sections to improve the
liquid cross-sections, which was found to enhance the accuracy of the transport
coefficient calculations.


title: The chaotic effects in a nonlinear QCD evolution equation

abstract:
  The corrections of gluon fusion to the DGLAP and BFKL equations are discussed
in a united partonic framework. The resulting nonlinear evolution equations are
the well-known GLR-MQ-ZRS equation and a new evolution equation. Using the
available saturation models as input, we find that the new evolution equation
has the chaos solution with positive Lyaponov exponents in the perturbative
range. We predict a new kind of shadowing caused by chaos, which blocks the QCD
evolution in a critical small $x$ range. The blocking effect in the evolution
equation may explain the Abelian gluon assumption and even influence our
expectations to the projected Large Hadron Electron Collider (LHeC), Very Large
Hadron Collider (VLHC) and the upgrade (CppC) in a circular $e^+e^-$ collider
(SppC).


title:
Hawking fluxes and Anomalies in Rotating Regular Black Holes with a
  Time-Delay

abstract:
  Based on the anomaly cancellation method we are going to compute the Hawking
fluxes (the Hawking thermal flux and the total flux of energy-momentum tensor)
from a four-dimensional rotating regular black hole with a time-delay. To this
purpose, in the three metrics proposed in arXiv:1510.08828, we try to perform
the dimensional reduction in which the anomaly cancellation method is feasible
at the near-horizon region in a general scalar field theory. As a result we can
demonstrate that the dimensional reduction is possible in two of those metrics.
Hence we perform the anomaly cancellation method and compute the Hawking fluxes
in those two metrics. Our Hawking fluxes involve the three effects: 1) the
quantum gravity effect regularizing the core of the black holes, 2) rotation of
the black hole, 3) the time-delay. Further in this paper toward the metric in
which the dimensional could not be performed, we argue that it would be some
problematic metric, and mention its cause. The Hawking fluxes we compute in
this study could be considered to correspond to more realistic Hawking fluxes.
Further what Hawking fluxes can be obtained from the anomaly cancellation
method would be interesting in terms of the relation between a consistency of
quantum field theories and black hole thermodynamics.


title:
Data assimilation for massive autonomous systems based on second-order
  adjoint method

abstract:
  Data assimilation (DA) is a fundamental computational technique that
integrates numerical simulation models and observation data on the basis of
Bayesian statistics. Originally developed for meteorology, especially weather
forecasting, DA is now an accepted technique in various scientific fields. One
key issue that remains controversial is the implementation of DA in massive
simulation models under limited computation time and resources. In this paper,
we propose an adjoint-based DA method for massive autonomous models that
produces optimum estimates and their uncertainties within practical computation
time and resource constraints. The uncertainties are given as several diagonal
components of an inverse Hessian matrix, which is the covariance matrix of a
normal distribution that approximates the target posterior probability density
function in the neighborhood of the optimum. Conventional algorithms for
deriving the inverse Hessian matrix require $O(CN^2+N^3)$ computations and
$O(N^2)$ memory, where $N$ is the number of degrees of freedom of a given
autonomous system and $C$ is the number of computations needed to simulate time
series of suitable length. The proposed method using a second-order adjoint
method allows us to directly evaluate the diagonal components of the inverse
Hessian matrix without computing all of its components. This drastically
reduces the number of computations to $O(C)$ and the amount of memory to $O(N)$
for each diagonal component. The proposed method is validated through numerical
tests using a massive two-dimensional Kobayashi's phase-field model. We confirm
that the proposed method correctly reproduces the parameter and initial state
assumed in advance, and successfully evaluates the uncertainty of the
parameter. Such information regarding uncertainty is valuable, as it can be
used to optimize the design of experiments.


title: Inverse Design of Inorganic Electrides

abstract:
  Electrides are ionic solids that consist of cationic frameworks and anionic
electrons trapped in the voids of lattices. Organic electrides exist in a large
abundance, but the thermal instability at room temperature and sensitivity to
moisture are bottlenecks that limit their practical uses. Known inorganic
electrides are rare but appear to have high thermal and chemical stability and
exhibit promising applications as electron-emitting materials, superior
catalysts and strong reducing agents. Here, we report a developed
inverse-design method that can be used to search for a large variety of
inorganic electrides. Our method utilizes the intrinsic property of
interstitial electron localization of electrides as the global variable
function being incorporated into the swarm-intelligence based structure
searches. Through screening 99 binary ionic compounds, we have designed 89 new
inorganic electrides that are classified into three-, two-, and
zero-dimensional species according to the way that the interstitial electrons
are localized and the conductive properties of the systems. Our work reveals
the rich abundance of inorganic electrides by extending them into more general
forms and provides new structure types for electrides that are not thought of
as before.


title:
A Bishop type inequality on metric measure spaces with Ricci curvature
  bounded below

abstract:
  We define a Bishop-type inequality on metric measure spaces with Riemannian
curvature-dimension condition. The main result in this short article is that
any RCD spaces with the Bishop-type inequalities possess only one regular set
in not only the measure theoretical sense but also the set theoretical one. As
a corollary, the Hausdorff dimension of such $RCD^*(K,N)$ spaces are exactly
$N$. We also prove that every tangent cone at any point on such RCD spaces is a
metric cone.


title:
A BP-MF-EP Based Iterative Receiver for Joint Phase Noise Estimation,
  Equalization and Decoding

abstract:
  In this work, with combined belief propagation (BP), mean field (MF) and
expectation propagation (EP), an iterative receiver is designed for joint phase
noise (PN) estimation, equalization and decoding in a coded communication
system. The presence of the PN results in a nonlinear observation model.
Conventionally, the nonlinear model is directly linearized by using the
first-order Taylor approximation, e.g., in the state-of-the-art soft-input
extended Kalman smoothing approach (soft-in EKS). In this work, MF is used to
handle the factor due to the nonlinear model, and a second-order Taylor
approximation is used to achieve Gaussian approximation to the MF messages,
which is crucial to the low-complexity implementation of the receiver with BP
and EP. It turns out that our approximation is more effective than the direct
linearization in the soft-in EKS with similar complexity, leading to
significant performance improvement as demonstrated by simulation results.


title: Quark ACM with topologically generated gluon mass

abstract:
  We investigate the effect of a small, gauge-invariant mass of the gluon on
the anomalous chromomagnetic moment of quarks (ACM) by perturbative
calculations at one loop level. The mass of the gluon is taken to have been
generated via a topological mass generation mechanism, in which the gluon
acquires a mass through its interaction with an antisymmetric tensor field
$B_{\mu \nu}$. For a small gluon mass $(<10$ MeV), we calculate the ACM at
momentum transfer $q^2=-M_Z^2$. We compare those with the ACM calculated for
the gluon mass arising from a Proca mass term. We find that the ACM of up,
down, strange and charm quarks vary significantly with the gluon mass, while
the ACM of top and bottom quarks show negligible gluon mass dependence. The
mechanism of gluon mass generation is most important for the strange quarks
ACM, but not so much for the other quarks. We also show the results at
$q^2=-m_t^2$. We find that the dependence on gluon mass at $q^2=-m_t^2$ is much
less than at $q^2=-M_Z^2$ for all quarks.


title: Fermionic Schwinger effect and induced current in de Sitter space

abstract:
  We explore Schwinger effect of spin 1/2 charged particles with static
electric field in 1+3 dimensional de Sitter spacetime. We analytically
calculate the vacuum expectation value of the spinor current which is induced
by the produced particles in the electric field. The renormalization is
performed with the adiabatic subtraction scheme. We find that the current
becomes negative, namely it flows in the direction opposite to the electric
field, if the electric field is weaker than a certain threshold value depending
on the fermion mass, which is also known to happen in the case of scalar
charged particles in 1+3 de Sitter spacetime. Contrary to the scalar case,
however, the IR hyperconductivity is absent in the spinor case.


title:
The Normal Law Under Linear Restrictions: Simulation and Estimation via
  Minimax Tilting

abstract:
  Simulation from the truncated multivariate normal distribution in high
dimensions is a recurrent problem in statistical computing, and is typically
only feasible using approximate MCMC sampling. In this article we propose a
minimax tilting method for exact iid simulation from the truncated multivariate
normal distribution. The new methodology provides both a method for simulation
and an efficient estimator to hitherto intractable Gaussian integrals. We prove
that the estimator possesses a rare vanishing relative error asymptotic
property. Numerical experiments suggest that the proposed scheme is accurate in
a wide range of setups for which competing estimation schemes fail. We give an
application to exact iid simulation from the Bayesian posterior of the probit
regression model.


title: Computations in quantum mechanics made easy

abstract:
  Convenient and simple numerical techniques for performing quantum
computations based on matrix representations of Hilbert space operators are
presented and illustrated by various examples. The applications include the
calculations of spectral and dynamical properties for one-dimensional and
two-dimensional single-particle systems as well as bosonic many-particle and
open quantum systems. Due to their technical simplicity these methods are well
suited as a tool for teaching quantum mechanics to undergraduates and
graduates. Explicit implementations of the presented numerical methods in
Matlab are given.


title: Hadronic molecular states from the $K\bar{K}^*$ interaction

abstract:
  In this work, the $K\bar{K}^*$ interaction is studied in a quasipotential
Bethe-Salpeter equation approach combined with the one-boson-exchange model.
With the help of the hidden-gauge Lagrangian, the exchanges of pseudoscalar
mesons ($\pi$ and $\eta$) and vector mesons ($\rho$, $\omega$ and $\phi$) are
considered to describe the $K\bar{K}^*$ interaction. Besides the direct
vector-meson exchange which can be related to the Weinberg-Tomozawa term,
pseudoscalar-meson exchanges also play important roles in the mechanism of the
$K\bar{K}^*$ interaction. The poles of scattering amplitude are searched to
find the molecular states produced from the $K\bar{K}^*$ interaction. In the
case of quantum number $I^G(J^{PC})=0^+(1^{++})$, a pole is found with a
reasonable cutoff, which can be related to the $f_1(1285)$ in experiment.
Another bound state with $0^-(1^{+-})$ is also produced from the $K\bar{K}^*$
interaction, which can be related to the $h_1(1380)$. In the isovector sector,
the interaction is much weaker and a bound state with $1^+(1^{+})$ relevant to
the $b_1(1235)$ is produced but at a larger cutoff. Our results suggest that in
the hadronic molecular state picture the $f_1(1285)$ and $b_1(1235)$ are the
strange partners of the $X(3872)$ and $Z_c(3900)$, respectively.


title:
Method for fast computation of angular light scattering spectra from 2D
  periodic arrays

abstract:
  An efficient numerical method for computing angle-resolved light scattering
off periodic arrays is presented. The method combines finite-element
discretization with a Schur complement solver. A significant speed-up of the
computations in comparison to standard finite-element method computations is
observed.


title:
Effective cosmological constant induced by stochastic fluctuations of
  Newton's constant

abstract:
  We consider implications of the microscopic dynamics of spacetime for the
evolution of cosmological models. We argue that quantum geometry effects may
lead to stochastic fluctuations of the gravitational constant, which is thus
considered as a macroscopic effective dynamical quantity. Consistency with
Riemannian geometry entails the presence of a time-dependent dark energy term
in the modified field equations, which can be expressed in terms of the
dynamical gravitational constant. We suggest that the late-time accelerated
expansion of the Universe may be ascribed to quantum fluctuations in the
geometry of spacetime rather than the vacuum energy from the matter sector.


title:
Primary black hole spin in OJ287 as determined by the General Relativity
  centenary flare

abstract:
  OJ287 is a quasi-periodic quasar with roughly 12 year optical cycles. It
displays prominent outbursts which are predictable in a binary black hole
model. The model predicted a major optical outburst in December 2015. We found
that the outburst did occur within the expected time range, peaking on 2015
December 5 at magnitude 12.9 in the optical R-band. Based on Swift/XRT
satellite measurements and optical polarization data, we find that it included
a major thermal component. Its timing provides an accurate estimate for the
spin of the primary black hole, chi = 0.313 +- 0.01. The present outburst also
confirms the established general relativistic properties of the system such as
the loss of orbital energy to gravitational radiation at the 2 % accuracy level
and it opens up the possibility of testing the black hole no-hair theorem with
a 10 % accuracy during the present decade.


title:
Optimal Estimation via Nonanticipative Rate Distortion Function and
  Applications to Time-Varying Gauss-Markov Processes

abstract:
  In this paper, we develop {finite-time horizon} causal filters using the
nonanticipative rate distortion theory. We apply the {developed} theory to
{design optimal filters for} time-varying multidimensional Gauss-Markov
processes, subject to a mean square error fidelity constraint. We show that
such filters are equivalent to the design of an optimal \texttt{\{encoder,
channel, decoder\}}, which ensures that the error satisfies {a} fidelity
constraint. Moreover, we derive a universal lower bound on the mean square
error of any estimator of time-varying multidimensional Gauss-Markov processes
in terms of conditional mutual information. Unlike classical Kalman filters,
the filter developed is characterized by a reverse-waterfilling algorithm,
which ensures {that} the fidelity constraint is satisfied. The theoretical
results are demonstrated via illustrative examples.


title: Analysis of Blink Rate Variability during reading and memory testing

abstract:
  In this paper we investigated how statistical properties of the blink rate
variability changes during two mental tasks: reading a passage and memory
testing. To construct time series of inter-blink intervals (blink rate
variability) we detected exact blink time in EEG recordings using our blink
detection algorithm. We found that among 13 subjects, all subjects blinked less
during reading session. Moreover, standard deviation of the blink rate
variability is higher during reading. Thus, we conclude that the variability of
inter-blink intervals decreases during tasks that require concentration and
intense mental activity.


title: On Nyquist-Shannon Theorem with one-sided half of sampling sequence

abstract:
  The classical sampling Nyquist-Shannon-Kotelnikov theorem states that a
band-limited continuous time function can be uniquely recovered without error
from a infinite two-sided sampling series taken with a sufficient frequency.
This short note shows that the function can be recovered from any one-sided
semi-infinite half of any oversampling series, with the same boundary for
admissible frequencies as in the classical theorem.


title: Chiral Unitary Quantum Phase Transition in 2H-Fe$_x$TaSe$_2$

abstract:
  We have observed a metal-insulator transition of a quasi-two dimensional
electronic system in transition metal dichalcogenide $2H$-TaSe$_2$ caused by
doping iron. The sheet resistance of $2H$-Fe$_x$TaSe$_2$ ($0 \leq x \leq
0.120$) single crystals rises about $10^6$ times with the increasing of $x$ at
the lowest temperature. We investigated the temperature dependence of the
resistance and found a metal-insulator transition with a critical sheet
resistance $11.7 \pm 5.4$ k$\rm{\Omega}$. The critical exponent of the
localization length $\nu$ is estimated $0.31 \pm 0.18$. The values of the
critical sheet resistance and $\nu$ are accordant to those of the
\textit{chiral unitary class} (less than $h/1.49e^2=17.3$ k$\rm{\Omega}$ and
$0.35 \pm 0.03$, respectively). We suggest that $2H$-Fe$_x$TaSe$_2$ is
classified as the chiral unitary class, not as standard unitary class.


title:
Missing continuous outcomes under covariate dependent missingness in
  cluster randomised trials

abstract:
  Attrition is a common occurrence in cluster randomised trials (CRTs) which
leads to missing outcome data. Two approaches for analysing such trials are
cluster-level analysis and individual-level analysis. This paper compares the
performance of unadjusted cluster-level analysis, baseline covariate adjusted
cluster-level analysis and linear mixed model (LMM) analysis, under baseline
covariate dependent missingness (CDM) in continuous outcomes, in terms of bias,
average estimated standard error and coverage probability. The methods of
complete case analysis (CCA) and multiple imputation (MI) are used to handle
the missing outcome data. Four possible scenarios are considered depending on
whether the missingness mechanisms and covariate effects on outcome are the
same or different in the two intervention groups. We show that both unadjusted
cluster-level analysis and baseline covariate adjusted cluster-level analysis
give unbiased estimates of the intervention effect only if both intervention
groups have the same missingness mechanisms and the same covariate effects,
which is arguably unlikely to hold in practice. LMM and MI give unbiased
estimates under all four considered scenarios, provided that an interaction of
intervention indicator and covariate is included in the model when the
covariate effects are different in the two intervention groups. MI gives
slightly overestimation of average standard error, which leads to a decrease in
power.


title:
The Effective Model of the Molecule Graphene System and One Application
  Beyond Graphene

abstract:
  Recently, a new kind of two dimensional (2D) artificial electron lattice,
i.e. molecule graphene, has drawn a lots of interest, where the metal surface
electrons are transformed into a honeycomb lattice via absorbing a molecule
lattice on metal surface. In this work, we would like to point out that the
technique used to build molecule graphene actually gives a promising way to
explore the interesting physics of other novel 2D lattice beyond graphene. The
key issue is that this system is an antidot system, where the absorbed molecule
normally gives a repulsive potential. So, we need to establish a map between
the molecule arrangement and the desired surface electron lattice. To give a
concrete example, we first analyse the effective models of molecule graphene,
and estimate the model parameters for the Cu/CO system through numerical
fitting the exerimental data. Then, we design a molecule lattice, and show
that, with this kind of lattice, the surface electrons can be transformed into
a Kagome like lattice. Using the estimated parameters of Cu/CO system, we
calculate the corresponding energy bands and LDOS, which can be readily tested
in experiment. We hope that our work can stimulate further theoretical and
experimental interest in this novel artificial 2D electron lattice.


title:
Stability Analysis and Design of Momentum-based Controllers for Humanoid
  Robots

abstract:
  Envisioned applications for humanoid robots call for the design of balancing
and walking controllers. While promising results have been recently achieved,
robust and reliable controllers are still a challenge for the control community
dealing with humanoid robotics. Momentum-based strategies have proven their
effectiveness for controlling humanoids balancing, but the stability analysis
of these controllers is still missing. The contribution of this paper is
twofold. First, we numerically show that the application of state-of-the-art
momentum-based control strategies may lead to unstable zero dynamics. Secondly,
we propose simple modifications to the control architecture that avoid
instabilities at the zero-dynamics level. Asymptotic stability of the closed
loop system is shown by means of a Lyapunov analysis on the linearized system's
joint space. The theoretical results are validated with both simulations and
experiments on the iCub humanoid robot.


title:
Performance Analysis of Source Image Estimators in Blind Source
  Separation

abstract:
  Blind methods often separate or identify signals or signal subspaces up to an
unknown scaling factor. Sometimes it is necessary to cope with the scaling
ambiguity, which can be done through reconstructing signals as they are
received by sensors, because scales of the sensor responses (images) have known
physical interpretations. In this paper, we analyze two approaches that are
widely used for computing the sensor responses, especially, in Frequency-Domain
Independent Component Analysis. One approach is the least-squares projection,
while the other one assumes a regular mixing matrix and computes its inverse.
Both estimators are invariant to the unknown scaling. Although frequently used,
their differences were not studied yet. A goal of this work is to fill this
gap. The estimators are compared through a theoretical study, perturbation
analysis and simulations. We point to the fact that the estimators are
equivalent when the separated signal subspaces are orthogonal, and vice versa.
Two applications are shown, one of which demonstrates a case where the
estimators yield substantially different results.


title:
Loose Hamiltonian cycles forced by large $(k-2)$-degree - approximate
  version

abstract:
  We prove that for all $k\geq 4$ and $1\leq\ell<k/2$, every $k$-uniform
hypergraph $\mathcal{H}$ on $n$ vertices with
$\delta_{k-2}(\mathcal{H})\geq\left(\frac{4(k-\ell)-1}{4(k-\ell)^2}+o(1)\right)\binom{n}{2}$
contains a Hamiltonian $\ell$-cycle if $k-\ell$ divides $n$. This degree
condition is asymptotically best possible. The case $k=3$ was addressed earlier
by Bu{\ss} et al.


title: Ripening Kinetics of Bubbles: A Molecular Dynamics Study

abstract:
  The ripening kinetics of bubbles is studied by performing molecular dynamics
simulations. From the time evolution of a system, the growth rates of
individual bubbles are determined. At low temperatures, the system exhibits a
$t^{1/2}$ law and the growth rate is well described by classical
Lifshitz-Slyozov-Wagner (LSW) theory for the reaction-limited case. This is
direct evidence that the bubble coarsening at low temperatures is
reaction-limited. At high temperatures, although the system exhibits a
$t^{1/3}$ law, which suggests that it is diffusion-limited, the accuracy of the
growth rate is insufficient to determine whether the form is consistent with
the prediction of LSW theory for the diffusion-limited case. The gas volume
fraction dependence of the coarsening behavior is also studied. Although the
behavior of the system at low temperatures has little sensitivity to the gas
volume fraction up to 10%, that at high temperatures deviates from the
prediction of LSW theory for the diffusion-limited case as the gas volume
fraction increases. These results show that the mean-field-like treatment is
valid for a reaction-limited system even with a finite volume fraction, while
it becomes inappropriate for a diffusion-limited system since classical LSW
theory for the diffusion-limited case is valid at the dilute limit.


title: Transverse electric surface mode in atomically thin Boron-Nitride

abstract:
  The spatial confinement and the propagation length of surface waves in a
single-layer two-dimensional atomic crystal are analysed in term of its surface
susceptibility and its surface conductivity. Based on the values of these
macroscopic parameters, extracted from experimental observations, it is
confirmed that graphene supports a transverse magnetic non-radiating surface
mode in the ultraviolet spectral region while a single-layer hexagonal
Boron-Nitride is predicted to support a transverse electric non-radiating
surface mode in the visible spectrum. This last mode, at a vacuum wavelength of
633 nm, has a spatial confinement of 15 microns and an intensity-propagation
distance greater than 2 cm.


title: Study of GRB light curve decay indices in the afterglow phase

abstract:
  In this work we study the distribution of temporal power-law decay indices,
$\alpha$, in the Gamma Ray Burst (GRB) afterglow phase, fitted for $176$ GRBs
(139 long GRBs, 12 short GRBs {\it with extended emission} and 25 X-Ray Flashes
(XRFs)) with known redshifts. These indices are compared with the temporal
decay index, $\alpha_W$, derived with the light curve fitting using the
\cite{willingale07} model. This model fitting yields similar distributions of
$\alpha_W$ to the fitted $\alpha$, but for individual bursts a difference can
be significant. Analysis of ($\alpha$, $L_a$) distribution, where $L_a$ is the
characteristic luminosity at the end of the plateau, reveals only a weak
correlation of these quantities. However, we discovered a significant regular
trend when studying GRB $\alpha$ values along the \cite{dainotti2008}
correlation between $L_a$ and the end time of the plateau emission in the rest
frame, $T_a^*$, hereafter LT correlation. We note a systematic variation of the
$\alpha$ parameter distribution with luminosity for any selected $T_a^*$. We
analyze this systematics with respect to the fitted LT correlation line,
expecting that the presented trend may allow to constrain the GRB physical
models. We also attempted to use the derived correlation of $\alpha(T_a)$
versus $L_a(T_a)$ to diminish the luminosity scatter related to the variations
of $\alpha$ along the LT distribution, a step forward in the effort of
standardizing GRBs. A proposed toy model accounting for this systematics
applied to the analyzed GRB distribution results in a slight increase of the LT
correlation coefficient.


title: ARX modeling of unstable linear systems

abstract:
  High-order ARX models can be used to approximate a quite general class of
linear systems in a parametric model structure, and well-established methods
can then be used to retrieve the true plant and noise models from the ARX
polynomials. However, this commonly used approach is only valid when the plant
is stable or if the unstable poles are shared with the true noise model. In
this contribution, we generalize this approach to allow the unstable poles not
to be shared, by introducing modifications to correctly retrieve the noise
model and noise variance.


title: $C^{1,\alpha}$ estimates for the fully nonlinear Signorini problem

abstract:
  We study the regularity of solutions to the fully nonlinear thin obstacle
problem. We establish local $C^{1,\alpha}$ estimates on each side of the smooth
obstacle, for some small $\alpha > 0$.
  Our results extend those of Milakis-Silvestre in two ways: first, we do not
assume solutions nor operators to be symmetric, and second, our estimates are
local, in the sense that do not rely on the boundary data.
  As a consequence, we prove $C^{1,\alpha}$ regularity even when the problem is
posed in general Lipschitz domains.


title: Visual Concept Recognition and Localization via Iterative Introspection

abstract:
  Convolutional neural networks have been shown to develop internal
representations, which correspond closely to semantically meaningful objects
and parts, although trained solely on class labels. Class Activation Mapping
(CAM) is a recent method that makes it possible to easily highlight the image
regions contributing to a network's classification decision. We build upon
these two developments to enable a network to re-examine informative image
regions, which we term introspection. We propose a weakly-supervised iterative
scheme, which shifts its center of attention to increasingly discriminative
regions as it progresses, by alternating stages of classification and
introspection. We evaluate our method and show its effectiveness over a range
of several datasets, where we obtain competitive or state-of-the-art results:
on Stanford-40 Actions, we set a new state-of the art of 81.74%. On
FGVC-Aircraft and the Stanford Dogs dataset, we show consistent improvements
over baselines, some of which include significantly more supervision.


title: Algebraic independence of $G$-functions and congruences "\`a la Lucas"

abstract:
  We develop a new method for proving algebraic independence of $G$-functions.
Our approach rests on the following observation: $G$-functions do not always
come with a single linear differential equation, but also sometimes with an
infinite family of linear difference equations associated with the Frobenius
that are obtained by reduction modulo prime ideals. When these linear
difference equations have order one, the coefficients of the $G$-function
satisfy congruences reminiscent of a classical theorem of Lucas on binomial
coefficients. We use this to derive a Kolchin-like algebraic independence
criterion. We show the relevance of this criterion by proving, using p-adic
tools, that many classical families of $G$-functions turn out to satisfy
congruences "\`a la Lucas".


title:
Nanofocusing, shadowing, and electron mean free path in the
  photoemission from aerosol droplets

abstract:
  Angle-resolved photoelectron spectroscopy of aerosol droplets is a promising
method for the determination of electron mean free paths in liquids. It is
particularly attractive for volatile liquids, such as water. Here we report the
first angle-resolved photoelectron images of droplets with defined sizes, viz.
of water, glycerol, and dioctyl phthalate droplets. Example simulations of
water droplet photoelectron images and data for electron mean free paths for
liquid water at low kinetic energy (< 3eV) are provided. We present an approach
that allows one to gradually vary the conditions from shadowing to nanofocusing
to optimize the information content contained in the photoelectron images.


title:
A Change-Point Model for Detecting Heterogeneity in Ordered Survival
  Responses

abstract:
  In this article we suggest a new statistical approach considering survival
heterogeneity as a breakpoint model in an ordered sequence of time to event
variables. The survival responses need to be ordered according to a numerical
covariate. Our esti- mation method will aim at detecting heterogeneity that
could arise through the or- dering covariate. We formally introduce our model
as a constrained Hidden Markov Model (HMM) where the hidden states are the
unknown segmentation (breakpoint locations) and the observed states are the
survival responses. We derive an efficient Expectation-Maximization (EM)
framework for maximizing the likelihood of this model for a wide range of
baseline hazard forms (parametrics or nonparametric). The posterior
distribution of the breakpoints is also derived and the selection of the number
of segments using penalized likelihood criterion is discussed. The performance
of our survival breakpoint model is finally illustrated on a diabetes dataset
where the observed survival times are ordered according to the calendar time of
disease onset.


title: Online Isotonic Regression

abstract:
  We consider the online version of the isotonic regression problem. Given a
set of linearly ordered points (e.g., on the real line), the learner must
predict labels sequentially at adversarially chosen positions and is evaluated
by her total squared loss compared against the best isotonic (non-decreasing)
function in hindsight. We survey several standard online learning algorithms
and show that none of them achieve the optimal regret exponent; in fact, most
of them (including Online Gradient Descent, Follow the Leader and Exponential
Weights) incur linear regret. We then prove that the Exponential Weights
algorithm played over a covering net of isotonic functions has a regret bounded
by $O\big(T^{1/3} \log^{2/3}(T)\big)$ and present a matching $\Omega(T^{1/3})$
lower bound on regret. We provide a computationally efficient version of this
algorithm. We also analyze the noise-free case, in which the revealed labels
are isotonic, and show that the bound can be improved to $O(\log T)$ or even to
$O(1)$ (when the labels are revealed in isotonic order). Finally, we extend the
analysis beyond squared loss and give bounds for entropic loss and absolute
loss.


title:
Singular equivalence of finite dimensional algebras with radical square
  zero

abstract:
  We prove that the Crisp and Gow's quiver operation on a finite quiver Q
produces a new quiver Q' with fewer vertices, such that the finite dimensional
algebras kQ/J^2 and kQ'/J^2 are singularly equivalent. This operation is a
general quiver operation which includes as specific examples some operations
which arise naturally in symbolic dynamics (e.g., (elementary) strong shift
equivalent, (in-out) splitting, source elimination, etc.).


title: About the mass corrections in an abelian Higgs model

abstract:
  We study the corrections to the scalar boson mass in an abelian Higgs model
by considering the global properties of the partition function. We find that
although the two point function for the Higgs boson receives quantum
corrections, the mass of the scalar remains unaltered and thus the physical
mass is equal to the bare one.


title: Semi-algebraic geometry with rational continuous functions

abstract:
  Let X be an affine real algebraic set . We investigate on the theory of
algebraically constructible functions on X and the description of the
semi-algebraic subsets of X when we replace the polynomial functions on X by
some rational continuous functions on X.


title:
Marginal standardization of upper semicontinuous processes. with
  application to max-stable processes

abstract:
  Extreme-value theory for random vectors and stochastic processes with
continuous trajectories is usually formulated for random objects all of whose
univariate marginal distributions are identical. In the spirit of Sklar's
theorem from copula theory, such marginal standardization is carried out by the
pointwise probability integral transform. Certain situations, however, call for
stochastic models whose trajectories are not continuous but merely upper
semicontinuous (usc). Unfortunately, the pointwise application of the
probability integral transform to a usc process does in general not preserve
the upper semicontinuity of the trajectories. In the present work, we give
sufficient conditions for marginal standardization of usc processes to be
possible, and we state a partial extension of Sklar's theorem for usc
processes. We specialize the results to max-stable processes whose marginal
distributions and normalizing sequences are allowed to vary with the
coordinate.


title: Channels of oxygen diffusion in single crystal rubrene revealed

abstract:
  Electronic devices made from organic materials have the potential to support
a more ecologically friendly and affordable future. However, the ability to
fabricate devices with well-defined and reproducible electrical and optical
properties is hindered by the sensitivity to the presence of chemical
impurities. Oxygen in particular is an impurity that can trap electrons and
modify conductive properties of some organic materials. Until now the
3-dimensional profiling of oxygen species in organic semiconductors has been
elusive and the effect of oxygen remains disputed. In this study we map out
high-spatial resolution 3-dimensional distributions of oxygen inclusions near
the surface of single crystal rubrene, using Time of Flight Secondary Ion Mass
Spectroscopy (TOF-SIMS). Channels of diffused oxygen, 'oxygen pillars', are
found extending from uniform oxygen inclusion layers at the surface. These
pillars extend to depths in excess of 1.8 {\mu}m and act as an entry point for
oxygen to diffuse along the ab-plane of the crystal with at least some of the
diffused oxygen molecularly binding to rubrene. Our investigation of surfaces
at different stages of evolution reveals the extent of oxygen inclusion, which
affects rubrene's optical and transport properties, and is consequently of
importance for the reliability and longevity of devices.


title:
Unbiased local solutions of partial differential equations via the
  Feynman-Kac Identities

abstract:
  The Feynman-Kac formulae (FKF) express local solutions of partial
differential equations (PDEs) as expectations with respect to some
complementary stochastic differential equation (SDE). Repeatedly sampling paths
from the complementary SDE enables the construction of Monte Carlo estimates of
local solutions, which are more naturally suited to statistical inference than
the numerical approximations obtained via finite difference and finite element
methods. Until recently, simulating from the complementary SDE would have
required the use of a discrete-time approximation, leading to biased estimates.
In this paper we utilize recent developments in two areas to demonstrate that
it is now possible to obtain unbiased solutions for a wide range of PDE models
via the FKF. The first is the development of algorithms that simulate diffusion
paths exactly (without discretization error), and so make it possible to obtain
Monte Carlo estimates of the FKF directly. The second is the development of
debiasing methods for SDEs, enabling the construction of unbiased estimates
from a sequence of biased estimates.


title:
Rotational symmetry breaking in the topological superconductor
  Sr$_x$Bi$_2$Se$_3$ probed by upper-critical field experiments

abstract:
  Recently it was demonstrated that Sr intercalation provides a new route to
induce superconductivity in the topological insulator Bi$_2$Se$_3$. Topological
superconductors are predicted to be unconventional, with mixed even and odd
parity Cooper pairs states. An adequate probe to test for unconventional
superconductivity is the upper critical field, $B_{c2}$. For a standard BCS
layered superconductor $B_{c2}$ shows an anisotropy when the magnetic field is
applied parallel and perpendicular to the layers, but is isotropic when the
field is rotated in the plane of the layers. Here we report measurements of the
upper critical field of superconducting Sr$_x$Bi$_2$Se$_3$ crystals ($T_c =
3.0$~K). Surprisingly, field-angle dependent magnetotransport measurements
reveal a large anisotropy of $B_{c2}$ when the magnet field is rotated in the
basal plane. The large two-fold anisotropy, while six-fold is anticipated,
cannot be explained with the Ginzburg-Landau anisotropic effective mass model
or flux flow induced by the Lorentz force. The rotational symmetry breaking of
$B_{c2}$ indicates unconventional superconductivity with an odd-parity
polarized triplet Cooper pair state ($\Delta_4$-pairing) recently proposed for
rhombohedral topological superconductors, or might have a structural nature,
such as self-organized stripe ordering of Sr atoms.


title: Constant Slope Maps on the Extended Real Line

abstract:
  For a transitive countably piecewise monotone Markov interval map we consider
the question whether there exists a conjugate map of constant slope. The answer
varies depending on whether the map is continuous or only piecewise continuous,
whether it is mixing or not, what slope we consider, and whether the conjugate
map is defined on a bounded interval, half-line or the whole real line (with
the infinities included).


title: Causal Consistency: Beyond Memory

abstract:
  In distributed systems where strong consistency is costly when not
impossible, causal consistency provides a valuable abstraction to represent
program executions as partial orders. In addition to the sequential program
order of each computing entity, causal order also contains the semantic links
between the events that affect the shared objects -- messages emission and
reception in a communication channel , reads and writes on a shared register.
Usual approaches based on semantic links are very difficult to adapt to other
data types such as queues or counters because they require a specific analysis
of causal dependencies for each data type. This paper presents a new approach
to define causal consistency for any abstract data type based on sequential
specifications. It explores, formalizes and studies the differences between
three variations of causal consistency and highlights them in the light of
PRAM, eventual consistency and sequential consistency: weak causal consistency,
that captures the notion of causality preservation when focusing on convergence
; causal convergence that mixes weak causal consistency and convergence; and
causal consistency, that coincides with causal memory when applied to shared
memory.


title:
Phase transitions and ordering structures of a model of chiral
  helimagnet in three dimensions

abstract:
  Phase transitions in a classical Heisenberg spin model of a chiral helimagnet
with the Dzyaloshinskii--Moriya (DM) interaction in three dimensions are
numerically studied. By using the event-chain Monte Carlo algorithm recently
developed for particle and continuous spin systems, we perform equilibrium
Monte Carlo simulations for large systems up to about $10^6$ spins. Without
magnetic fields, the system undergoes a continuous phase transition with
critical exponents of the three-dimensional \textit{XY} model, and a uniaxial
periodic helical structure emerges in the low temperature region. In the
presence of a magnetic field perpendicular to the axis of the helical
structure, it is found that there exists a critical point on the temperature
and magnetic-field phase diagram and that above the critical point the system
exhibits a phase transition with strong divergence of the specific heat and the
uniform magnetic susceptibility.


title: Sufficient conditions for the existence of limiting Carleman weights

abstract:
  In https://arxiv.org/abs/1411.4887, we found some necessary conditions for a
Riemannian manifold to admit a local limiting Carleman weight (LCW), based upon
the Cotton-York tensor in dimension $3$ and the Weyl tensor in dimension $4$.
In this paper, we find further necessary conditions for the existence of local
LCWs that are often sufficient. For a manifold of dimension $3$ or $4$, we
classify the possible Cotton-York, or Weyl tensors, and provide a mechanism to
find out whether the manifold admits local LCW for each type of tensor. In
particular, we show that a product of two surfaces admits a LCW if and only if
at least one of the two surfaces is of revolution. This provides an example of
a manifold satisfying the eigenflag condition of \cite{AFGR} but not admitting
$LCW$.


title:
Mellin Analysis and its distance concept. Applications to sampling
  theory

abstract:
  In this paper a notion of functional "distance" in the Mellin transform
setting is introduced and a general representation formula is obtained for it.
Also, a determination of the distance is given in terms of Lipschitz classes
and Mellin-Sobolev spaces. Finally applications to approximate versions of
certain basic relations valid for Mellin band-limited functions are studied in
details.


title: Graph Based Sinogram Denoising for Tomographic Reconstructions

abstract:
  Limited data and low dose constraints are common problems in a variety of
tomographic reconstruction paradigms which lead to noisy and incomplete data.
Over the past few years sinogram denoising has become an essential
pre-processing step for low dose Computed Tomographic (CT) reconstructions. We
propose a novel sinogram denoising algorithm inspired by the modern field of
signal processing on graphs. Graph based methods often perform better than
standard filtering operations since they can exploit the signal structure. This
makes the sinogram an ideal candidate for graph based denoising since it
generally has a piecewise smooth structure. We test our method with a variety
of phantoms and different reconstruction methods. Our numerical study shows
that the proposed algorithm improves the performance of analytical filtered
back-projection (FBP) and iterative methods ART (Kaczmarz) and SIRT
(Cimmino).We observed that graph denoised sinogram always minimizes the error
measure and improves the accuracy of the solution as compared to regular
reconstructions.


title: On the spatial coordinate measurement of two identical particles

abstract:
  Theoretically, the coordinate measurement of two identical particles at a
point by two narrowly separated narrow detectors, is interpreted in the limit
of shrinking width and separation, as the detection of two particles by a
single narrow detector. { Ordinarily, the ratio between probabilities of point
measurements is independent of the width of the narrow detectors.} We show here
that not only this is not the case, but that in some scenarios the results
depend on the way the dimensions shrink to zero. The ratio between the width
and the separation determines the detection result. { In particular, it is
shown that the bunching parameter of bosons is not a well-defined physical
property. Moreover, it may suggests that } there is a difficulty in quantum
measurement theory in the interpretation of coordinate measurement of two
particles.


title: TeV scale mirage mediation in NMSSM and precision Higgs measurement

abstract:
  We propose that the TeV scale mirage mediation in the Next-to-Minimal
Supersymmetric Standard Model (NMSSM) is a novel solution for the little
hierarchy problem in supersymmetry. The 125 GeV Higgs boson can be accommodated
with the new quartic coupling or the mixing with the singlet. The fine-tuning
measures are estimated numerically and found as low as 10\% or below for $1.5$
TeV gluino and $1$ TeV stop. The higgsino can be as heavy as 500 GeV without
deteriorating the fine-tuning. An undesirable singlet-doublet mixing in the
Higgs sector is suppressed due to approximate scale symmetries. We investigate
the couplings of the Higgs bosons and discuss the prospects for studying them
at LHC and ILC.


title: Thermal decoherence of a nonequilibrium polariton fluid

abstract:
  Exciton-polaritons constitute a unique realization of a quantum fluid
interacting with its environment. Using Selenide based microcavities, we
exploit this feature to warm up a polariton condensate in a controlled way and
monitor its spatial coherence. We determine directly the amount of heat picked
up by the condensate by measuring the phonon-polariton scattering rate and
comparing it with the loss rate. We find that upon increasing the heating rate,
the spatial coherence length decreases markedly, while localized phase
structures vanish, in good agreement with a stochastic mean field theory. From
the thermodynamical point-of-view, this regime is unique as it involves a
nonequilibrium quantum fluid with no well-defined temperature, but which is
nevertheless able to pick up heat with dramatic effects on the order parameter.


title:
Phase speed and frequency-dependent damping of longitudinal intensity
  oscillations in coronal loop structures observed with AIA/SDO

abstract:
  Longitudinal intensity oscillations along coronal loops that are interpreted
as signatures of magneto-acoustic waves are observed frequently in different
coronal structures. The aim of this paper is to estimate the physical
parameters of the slow waves and the quantitative dependence of these
parameters on their frequencies in the solar corona loops that are situated
above active regions with the Atmospheric Imaging Assembly (AIA) onboard Solar
Dynamic Observatory (SDO). The observed data on 2012-Feb-12, consisting of 300
images with an interval of 24 seconds in the 171 $\rm{\AA}$ and 193 $\rm{\AA}$
passbands is analyzed for evidence of propagating features as slow waves along
the loop structures. Signatures of longitudinal intensity oscillations that are
damped rapidly as they travel along the loop structures were found, with
periods in the range of a few minutes to few tens of minutes. Also, the
projected (apparent) phase speeds, projected damping lengths, damping times and
damping qualities of filtered intensities centred on the dominant frequencies
are measured in the range of $\rm{C_s}\simeq 38-79~ \rm {km~s^{-1}}$,
$\rm{L_d}\simeq 23-68 ~\rm{Mm }$, $\rm{\tau_d}\simeq 7- 21 ~\rm {min}$ and
$\rm{\tau_d/P}\simeq 0.34- 0.77$, respectively. The theoretical and
observational results of this study indicate that the damping times and damping
lengths increase with increasing the oscillation periods, and are highly
sensitive function of oscillation period, but the projected speeds and the
damping qualities are not very sensitive to the oscillation periods.
Furthermore, the magnitude values of physical parameters are in good agreement
with the prediction of the theoretical dispersion relations of high-frequency
MHD waves ($>1.1~ \rm{mHz}$) in a coronal plasma with electron number density
in the range of $\rm{n_e}\simeq 10^{7} - 10^{12} ~\rm{cm^{-3}}$.


title:
XY ring exchange model with frustrated Ising coupling on the triangular
  lattice

abstract:
  We investigate the nature of a $Z_2$-invariant XY ring-exchange interaction
with a frustrated Ising coupling on the triangular lattice. In the limit of
pure XY ring-exchange interaction, we show that the classical ground state is
degenerate resulting from the $Z_2$-invariance of the Hamiltonian. Quantum
fluctuations lift these classical degenerate ground states and produce an
unusual state whose excitation spectrum exhibits a gapped maximum quadratic
dispersion near ${\bf k}=0$ and vanishes at the midpoints of each side of the
Brillouin zone. This result is in contrast to a gapless quadratic dispersion
near ${\bf k}=0$ in the U(1)-invariant counterpart. We also study the effects
of frustration when competing with a classically frustrated Ising interaction.
We provide a glimpse into the possible quantum phases that could emerge. A
comprehensive understanding of this Hamiltonian, however, cannot be elucidated
analytically and requires an explicit numerical simulation.


title:
The Stokes phenomenon for certain partial differential equations with
  meromorphic initial data

abstract:
  We study the Stokes phenomenon for the solutions of the 1-dimensional complex
heat equation and its generalizations with meromorphic initial data. We use the
theory of Borel summability for the description of the Stokes lines, the
anti-Stokes lines, jumps across the Stokes lines, and the maximal family of the
solutions.


title: The Runaway Rectangle Escape Problem

abstract:
  Motivated by the applications of routing in PCB buses, the Rectangle Escape
Problem was recently introduced and studied. In this problem, we are given a
set of rectangles $\mathcal{S}$ in a rectangular region $R$, and we would like
to extend these rectangles to one of the four sides of $R$. Define the density
of a point $p$ in $R$ as the number of extended rectangles that contain $p$.
The question is then to find an extension with the smallest maximum density.
  We consider the problem of maximizing the number of rectangles that can be
extended when the maximum density allowed is at most $d$. It is known that this
problem is polynomially solvable for $d = 1$, and NP-hard for any $d \geq 2$.
We consider approximation and exact algorithms for fixed values of $d$. We also
show that a very special case of this problem, when all the rectangles are unit
squares from a grid, continues to be NP-hard for $d = 2$.


title:
The number of distinct and repeated squares and cubes in the Fibonacci
  sequence

abstract:
  The Fibonacci sequence $\mathbb{F}$ is the fixed point beginning with $a$ of
morphism $\sigma(a,b)=(ab,a)$. In this paper, we get the explicit expressions
of all squares and cubes, then we determine the number of distinct squares and
cubes in $\mathbb{F}[1,n]$ for all $n$, where $\mathbb{F}[1,n]$ is the prefix
of $\mathbb{F}$ of length $n$. By establishing and discussing the recursive
structure of squares and cubes, we give algorithms for counting the number of
repeated squares and cubes in $\mathbb{F}[1,n]$ for all $n$, and get explicit
expressions for some special $n$ such as $n=f_m$ (the Fibonacci number) etc.,
which including some known results such as in A.S.Fraenkel and J.Simpson,
J.Shallit et al.


title:
Amenability and paradoxical decompositions for pseudogroups and for
  discrete metric spaces

abstract:
  This is an expostion of various aspects of amenability and paradoxical
decompositions for groups, group actions and metric spaces. First, we review
the formalism of pseudogroups, which is well adapted to stating the alternative
of Tarski, according to which a pseudogroup without invariant mean gives rise
to paradoxical decompositions, and to defining a F{\o}lner condition. Using a
Hall-Rado Theorem on matchings in graphs, we show then for pseudogroups that
existence of an invariant mean is equivalent to the F{\o}lner condition; in the
case of the pseudogroup of bounded perturbations of the identity on a locally
finite metric space, these conditions are moreover equivalent to the negation
of the Gromov's so-called doubling condition, to isoperimetric conditions, to
Kesten's spectral condition for related simple random walks, and to various
other conditions. We define also the minimal Tarski number of paradoxical
decompositions associated to a non-amenable group action (an integer $\ge 4$),
and we indicate numerical estimates (Sections II.4 and IV.2). The final chapter
explores for metric spaces the notion of supramenability, due for groups to
Rosenblatt.


title:
Supersymmetric extended string field theory in NS^n sector and
  NS^{n-1}-R sector

abstract:
  We construct a class of quadratic gauge invariant actions for extended string
fields defined on the tensor product of open superstring state space for
multiple open string Neveu-Schwarz (NS) sectors with or without one Ramond (R)
sector. The basic idea is the same as for the bosonic extended string field
theory developed by the authors [arXiv:1309.3850]. The theory for NS^n sector
and NS^{n-1}-R sector contains general n-th rank tensor fields and (n-1)-th
rank spinor-tensor fields in the massless spectrum respectively. In principle,
consistent gauge invariant actions for any generic type of 10-dimensional
massive or massless tensor or spinor-tensor fields can be extracted from the
theory. We discuss some simple examples of bosonic and fermionic massless
actions.


title: Time evolution of nanoscale systems by finite difference method

abstract:
  Using finite difference method, time evolution of a typical metal molecule
metal system is studied by introducing a new method to solve general related
Volterra integro differential equation (IDE). Discretization in time domain is
applied for one dimentional chain tight binding model in several cases by
defining a matrix integro-differential equation (MIDE). Results are compatible
with their analytical counterparts and show more accuracy than other numerical
methods like Runge Kutta (RK). Charge transport properties in a trans
polyacetylene chain are found by studying the time evolution of charge density
in it and current voltage diagram is calculated.


title: New MAX Phase Compound Mo2TiAlC2: First-principles Study

abstract:
  A theoretical study of Mo2TiAlC2 compound belonging to the MAX phases has
been performed by using the firstprinciples pseudopotential plane-wave method
within the generalized gradient approximation. We have calculated the
structural, elastic, electronic and optical properties of Mo2TiAlC2. To confirm
mechanical stability, the elastic constants Cij are calculated. Other elastic
parameters such as bulk modulus, shear modulus, compressibility, Young modulus,
anisotropic factor, Pugh ratio, Poisson ratio are also calculated. The energy
band structure and density of states are calculated and analyzed. The results
show that the electrical conductivity is metallic with a high density of states
at the Fermi level in which Mo 4d states dominate. Furthermore, the optical
properties such as dielectric function, refractive index, photoconductivity,
absorption coefficients, loss function and reflectivity are also calculated.
Its reflectance spectrum shows that it has the potential to be used as a
promising shielding material to avoid solar heating.


title:
Quarter-BPS solutions in three-dimensional N=16 supergravity and the
  Liouville equation

abstract:
  We show how by assuming at least 8 real timelike supersymmetries in the
maximally supersymmetric three-dimensional ungauged supergravity and a further
simplifying Ansatz, we are naturally led to a pair of Liouville field
equations. We also show that there are no solutions that preserve only 6 real
timelike supersymmetries. The solution relies on the classification of complex
spinors of Spin(8) to which the problem quickly reduces.


title:
Analytical studies of Spectrum Broadcast Structures in Quantum Brownian
  Motion

abstract:
  Spectrum Broadcast Structures are a new and fresh concept in the
quantum-to-classical transition, introduced recently in the context of
decoherence and the appearance of objective features in quantum mechanics.
These are specific quantum state structures, responsible for an apparent
objectivity of a decohered state of a system. Recently they have been shown to
appear in the well known Quantum Brownian Motion model, however the final
analysis relied on numerics. Here, after a presentation of the main concepts,
we perform analytical studies of the model, showing the timescales and the
efficiency of the spectrum broadcast structure formation. We consider a massive
central system and a somewhat simplified environment being random with a
uniform distribution of the frequencies.


title:
Equatorial superrotation in Held & Suarez-like flows with weak
  equator-to-pole surface temperature gradient

abstract:
  Equatorial superrotation under zonally-symmetric thermal forcing is
investigated in a setup close to that of the classic Held & Suarez (1994)
setup. In contrast to the behaviour in the classic setup, a transition to
equatorial superrotation occurs when the equator-to-pole surface equilibrium
entropy gradient is weakened. Two factors contribute to this transition: 1) the
reduction of breaking Rossby waves from the mid-latitude that decelerate the
equatorial flow and 2) the presence of barotropic instability in the equatorial
region, providing stirring to accelerate the equatorial flow. In the latter,
Kelvin waves excited by instability near the equator generate and maintain the
superrotation. However, the superrotation is unphysically enhanced if
simulations are under-resolved and/or over-dissipated.


title:
On the initial value problem for the Navier-Stokes equations with the
  initial datum in the Sobolev spaces

abstract:
  In this paper, we study local well-posedness for the Navier-Stokes equations
with arbitrary initial data in homogeneous Sobolev spaces
$\dot{H}^s_p(\mathbb{R}^d)$ for $d \geq 2, p > \frac{d}{2},\ {\rm and}\
\frac{d}{p} - 1 \leq s < \frac{d}{2p}$. The obtained result improves the known
ones for $p > d$ and $s = 0$ (see M. Cannone (1995), M. Cannone and Y. Meyer
(1995)). In the case of critical indexes $s=\frac{d}{p}-1$, we prove global
well-posedness for Navier-Stokes equations when the norm of the initial value
is small enough. This result is a generalization of the ones in Cannone (1999)
and P. G. Lemarie-Rieusset (2002) in which $(p = d, s = 0)$ and $(p > d, s =
\frac{d}{p} - 1)$, respectively.


title:
What can the 2008/10 broadband flare of PKS 1502+106 tell us? Nuclear
  opacity, magnetic fields, and the location of gamma rays

abstract:
  Context. The origin of blazar variability, seen from radio up to gamma rays,
is still a heavily debated matter and broadband flares offer a unique testbed
towards a better understanding of these extreme objects. Such an energetic
outburst was detected by Fermi/LAT in 2008 from the blazar PKS 1502+106. The
outburst was observed from gamma rays down to radio frequencies.
  Aims. Through the delay between flare maxima at different radio frequencies,
we study the frequency-dependent position of the unit-opacity surface and infer
its absolute position with respect to the jet base. This nuclear opacity
profile enables the magnetic field tomography of the jet. We also localize the
gamma-ray emission region and explore the mechanism producing the flare.
  Methods. The radio flare of PKS 1502+106 is studied through single-dish flux
density measurements at 12 frequencies in the range 2.64 to 226.5 GHz. To
quantify it, we employ both a Gaussian process regression and a discrete
cross-correlation function analysis.
  Results. We find that the light curve parameters (flare amplitude and
cross-band delays) show a power-law dependence on frequency. Delays decrease
with frequency, and the flare amplitudes increase up to about 43 GHz and then
decay. This behavior is consistent with a shock propagating downstream the jet.
The self-absorbed radio cores are located between about 10 and 4 pc from the
jet base and their magnetic field strengths range between 14 and 176 mG, at the
frequencies 2.64 to 86.24 GHz. Finally, the gamma-ray active region is located
at (1.9 +/- 1.1) pc away from the jet base.


title:
First 3 mm-VLBI imaging of the two-sided jet in Cygnus A. Zooming into
  the launching region

abstract:
  We present for the first time Very-Long-Baseline Interferometry images of the
radio galaxy Cygnus A at the frequency of $86$ $\rm GHz$. Thanks to the high
spatial resolution of only ${\sim}200$ Schwarzschild radii ($R_{\bf S}$), such
observations provide an extremely detailed view of the nuclear regions in this
archetypal object and allow us to derive important constraints for theoretical
models describing the launching of relativistic jets. A pixel-based analysis of
the jet outflow, which still appears two-sided on the scales probed, was
performed. By fitting Gaussian functions to the transverse intensity profiles,
we could determine the jet width in the nuclear region. The base of the jets
appears wide. The minimum measured transverse width of ${\sim} (227\pm98)$
$R_{\bf S}$ is significantly larger than the radius of the Innermost Stable
Circular Orbit, suggesting that the outer accretion disk is contributing to the
jet launching. The existence of a faster and Doppler de-boosted inner section,
powered either from the rotation of the inner regions of the accretion disk or
by the spinning black hole, is suggested by the kinematic properties and by the
observed limb brightening of the flow.


title:
Multiple seed structure and disconnected networks in respondent-driven
  sampling

abstract:
  Respondent-driven sampling (RDS) is a link-tracing sampling method that is
especially suitable for sampling hidden populations. RDS combines an efficient
snowball-type sampling scheme with inferential procedures that yield unbiased
population estimates under some assumptions about the sampling procedure and
population structure. Several seed individuals are typically used to initiate
RDS recruitment. However, standard RDS estimation theory assume that all
sampled individuals originate from only one seed. We present an estimator,
based on a random walk with teleportation, which accounts for the multiple seed
structure of RDS. The new estimator can also be used on populations with
disconnected social networks. We numerically evaluate our estimator by
simulations on artificial and real networks. Our estimator outperforms previous
estimators, especially when the proportion of seeds in the sample is large. We
recommend our new estimator to be used in RDS studies, in particular when the
number of seeds is large or the social network of the population is
disconnected.


title:
Investigation of event-based memory surfaces for high-speed tracking,
  unsupervised feature extraction and object recognition

abstract:
  In this paper we compare event-based decaying and time based-decaying memory
surfaces for high-speed eventbased tracking, feature extraction, and object
classification using an event-based camera. The high-speed recognition task
involves detecting and classifying model airplanes that are dropped free-hand
close to the camera lens so as to generate a challenging dataset exhibiting
significant variance in target velocity. This variance motivated the
investigation of event-based decaying memory surfaces in comparison to
time-based decaying memory surfaces to capture the temporal aspect of the
event-based data. These surfaces are then used to perform unsupervised feature
extraction, tracking and recognition. In order to generate the memory surfaces,
event binning, linearly decaying kernels, and exponentially decaying kernels
were investigated with exponentially decaying kernels found to perform best.
Event-based decaying memory surfaces were found to outperform time-based
decaying memory surfaces in recognition especially when invariance to target
velocity was made a requirement. A range of network and receptive field sizes
were investigated. The system achieves 98.75% recognition accuracy within 156
milliseconds of an airplane entering the field of view, using only twenty-five
event-based feature extracting neurons in series with a linear classifier. By
comparing the linear classifier results to an ELM classifier, we find that a
small number of event-based feature extractors can effectively project the
complex spatio-temporal event patterns of the dataset to an almost linearly
separable representation in feature space.


title:
CPMD/GULP QM/MM Interface for Modeling Periodic Solids: Implementation
  and its Application in the Study of Y-Zeolite Supported Rh$_n$ Clusters

abstract:
  We report here the development of hybrid quantum mechanics/molecular
mechanics (QM/MM) interface between the plane-wave density functional theory
based CPMD code and the empirical force-field based GULP code for modeling
periodic solids and surfaces. The hybrid QM/MM interface is based on the
electrostatic coupling between QM and MM regions. The interface is designed for
carrying out full relaxation of all the QM and MM atoms during geometry
optimizations and molecular dynamics simulations, including the boundary atoms.
Both Born-Oppenheimer and Car-Parrinello molecular dynamics schemes are enabled
for the QM part during the QM/MM calculations. This interface has the advantage
of parallelization of both the programs such that the QM and MM force
evaluations can be carried out in parallel in order to model large systems. The
interface program is first validated for total energy conservation and parallel
scaling performance is benchmarked. Oxygen vacancy in {\alpha}-cristobalite is
then studied in detail and the results are compared with a fully QM calculation
and experimental data. Subsequently, we use our implementation to investigate
the structure of rhodium cluster (Rh$_n$ ; $n$=2 to 6) formed from
Rh(C$_2$H$_4$)$_2$ complex adsorbed within a cavity of Y-zeolite in a reducible
atmosphere of H$_2$ gas.


title:
Linguistic neighbourhoods: explaining cultural borders on Wikipedia
  through multilingual co-editing activity

abstract:
  In this paper, we study the network of global interconnections between
language communities, based on shared co-editing interests of Wikipedia
editors, and show that although English is discussed as a potential lingua
franca of the digital space, its domination disappears in the network of
co-editing similarities, and instead local connections come to the forefront.
Out of the hypotheses we explored, bilingualism, linguistic similarity of
languages, and shared religion provide the best explanations for the similarity
of interests between cultural communities. Population attraction and
geographical proximity are also significant, but much weaker factors bringing
communities together. In addition, we present an approach that allows for
extracting significant cultural borders from editing activity of Wikipedia
users, and comparing a set of hypotheses about the social mechanisms generating
these borders. Our study sheds light on how culture is reflected in the
collective process of archiving knowledge on Wikipedia, and demonstrates that
cross-lingual interconnections on Wikipedia are not dominated by one powerful
language. Our findings also raise some important policy questions for the
Wikimedia Foundation.


title:
Generalized shear-ratio tests: A new relation between cosmological
  distances, and a diagnostic for a redshift-dependent multiplicative bias in
  shear measurements

abstract:
  We derive a new relation between cosological distances, valid in any
(statistically) isotropic space-time and independent of cosmological parameters
or even the validity of the field equation of General Relativity. In
particular, this relation yields an equation between those distance ratios
which are the geometrical factors determining the strength of the gravitational
lensing effect of mass concentrations. Considering a combination of weak
lensing shear ratios, based on lenses at two different redshifts, and sources
at three different redshifts, we derive a relation between shear-ratio tests
which must be identically satisfied. A redshift-dependent multiplicative bias
in shear estimates will violate this relation, and thus can be probed by this
generalized shear-ratio test. Combining the lensing effect for lenses at three
different redshifts and three different source redshifts, a relation between
shear ratios is derived which must be valid independent of a multiplicative
bias. We propose these generalized shear-ratio tests as a diagnostic for the
presence of systematics in upcoming weak lensing surveys.


title: Screening corrections to the Coulomb crystal elastic moduli

abstract:
  Corrections to elastic moduli, including the effective shear modulus, of a
solid neutron star crust due to electron screening are calculated. At any given
mass density, the crust is modelled as a body-centred cubic Coulomb crystal of
fully ionized atomic nuclei of a single type with a polarizable
charge-compensating electron background. Motion of the nuclei is neglected. The
electron polarization is described by a simple Thomas-Fermi model of
exponential electron screening. The results of numerical calculations are
fitted by convenient analytic formulae. They should be used for precise neutron
star oscillation modelling, a rapidly developing branch of stellar seismology.


title:
A practical multi-party computation algorithm for a secure distributed
  online voting system

abstract:
  We present an online voting architecture based on partitioning the election
in small clusters of voters and using a new Multi-party Computation algorithm
for obtaining voting results from the clusters. This new algorithm has some
practical advantages over other previously known algorithms and isn't bound to
any specific cryptographic concept; so it can be adapted to future
cryptographic exigencies. Compared with other online voting technologies, we
see that this new architecture is less vulnerable to hacker attacks and attacks
from dishonest authorities, given that no sensitive information is stored in
any public server and there is no need for any trustee to safeguard the
legality of the election process. Even in case of an attack succeeding, the
risks associated with the overall election are far lower than with any other
voting system. This architecture can also be combined with any other voting
system, inheriting advantages from both systems.


title:
kdecopula: An R Package for the Kernel Estimation of Bivariate Copula
  Densities

abstract:
  We describe the R package kdecopula (current version 0.9.0), which provides
fast implementations of various kernel estimators for the copula density. Due
to a variety of available plotting options it is particularly useful for the
exploratory analysis of dependence structures. It can be further used for
accurate nonparametric estimation of copula densities and resampling. The
implementation features spline interpolation of the estimates to allow for fast
evaluation of density estimates and integrals thereof. We utilize this for a
fast renormalization scheme that ensures that estimates are bona fide copula
densities and additionally improves the estimators' accuracy. The performance
of the methods is illustrated by simulations.


title: An efficient magic state approach to small angle rotations

abstract:
  Standard error correction techniques only provide a quantum memory and need
extra gadgets to perform computation. Central to quantum algorithms are small
angle rotations, which can be fault-tolerantly implemented given a supply of an
unconventional species of magic state. We present a low-cost distillation
routine for preparing these small angle magic states. Our protocol builds on
the work of Duclos-Cianci and Poulin [Phys. Rev. A, 91, 042315 (2015)] by
compressing their circuit. Additionally, we present a method of diluting magic
states that reduces costs associated with very small angle rotations. We
quantify performance by the expected number of noisy magic states consumed per
rotation, and compare with other protocols. For modest size angles, our
protocols offer a factor 24 improvement over the best known gate synthesis
protocols and a factor 2 over the Duclos-Cianci and Poulin protocol. For very
small angle rotations, the dilution protocol dramatically reduces costs, giving
several orders magnitude improvement over competitors. There also exists an
intermediary regime of small, but not very small, angles where our approach
gives a marginal improvement over gate synthesis. We discuss how different
performance metrics may alter these conclusions.


title: Multivariable ({\phi},{\Gamma})-modules and products of Galois groups

abstract:
  We show that the category of continuous representations of the $d$th direct
power of the absolute Galois group of $\mathbb{Q}_p$ on finite dimensional
$\mathbb{F}_p$-vector spaces (resp. finitely generated $\mathbb{Z}_p$-modules,
resp. finite dimensional $\mathbb{Q}_p$-vector spaces) is equivalent to the
category of \'etale $(\varphi,\Gamma)$-modules over a $d$-variable
Laurent-series ring over $\mathbb{F}_p$ (resp. over $\mathbb{Z}_p$, resp. over
$\mathbb{Q}_p$).


title: Laser Ion Acceleration from Mass-Limited Targets with Preplasma

abstract:
  The interaction of high intensity laser radiation with mass-limited target
exhibits significant enhancement of the ion acceleration when the target is
surrounded by an underdense plasma corona, as seen in numerical simulations.
The self-generated quasistatic magnetic field squeezes the corona causing the
intensification of a subsequent Coulomb explosion of the target. The electric
field intensification at the target edges and plasma resonance effects result
in the generation of characteristic density holes and further contributes to
the ion acceleration.The interaction of high intensity laser radiation with
mass-limited target exhibits significant enhancement of the ion acceleration
when the target is surrounded by an underdense plasma corona, as seen in
numerical simulations. The self-generated quasistatic magnetic field squeezes
the corona causing the intensification of a subsequent Coulomb explosion of the
target. The electric field intensification at the target edges and plasma
resonance effects result in the generation of characteristic density holes and
further contributes to the ion acceleration.


title: Global weak solutions to a strongly degenerate haptotaxis model

abstract:
  We consider a one-dimensional version of a model obtained in [C. Engwer, A.
Hunt, and C. Surulescu: Effective equations for anisotropic glioma spread with
proliferation: a multiscale approach and comparisons with previous settings,
IMA J. Math. Med. Biol. (2015), doi: 10.1093/imammb/dqv030] and describing the
anisotropic spread of tumor cells in a tissue network. The model consists of a
reaction-diffusion-taxis equation for the density of tumor cells coupled with
an ODE for the density of tissue fibers and allows for strong degeneracy both
in the diffusion and the haptotaxis terms. In this setting we prove the global
existence of weak solutions to an associated no-flux initial-boundary value
problem.


title: Convergecast and Broadcast by Power-Aware Mobile Agents

abstract:
  A set of identical, mobile agents is deployed in a weighted network. Each
agent has a battery -- a power source allowing it to move along network edges.
An agent uses its battery proportionally to the distance traveled. We consider
two tasks : convergecast, in which at the beginning, each agent has some
initial piece of information, and information of all agents has to be collected
by some agent; and broadcast in which information of one specified agent has to
be made available to all other agents. In both tasks, the agents exchange the
currently possessed information when they meet. The objective of this paper is
to investigate what is the minimal value of power, initially available to all
agents, so that convergecast or broadcast can be achieved. We study this
question in the centralized and the distributed settings. In the centralized
setting, there is a central monitor that schedules the moves of all agents. In
the distributed setting every agent has to perform an algorithm being unaware
of the network. In the centralized setting, we give a linear-time algorithm to
compute the optimal battery power and the strategy using it, both for
convergecast and for broadcast, when agents are on the line. We also show that
finding the optimal battery power for convergecast or for broadcast is NP-hard
for the class of trees. On the other hand, we give a polynomial algorithm that
finds a 2-approximation for convergecast and a 4-approximation for broadcast,
for arbitrary graphs. In the distributed setting, we give a 2-competitive
algorithm for convergecast in trees and a 4-competitive algorithm for broadcast
in trees. The competitive ratio of 2 is proved to be the best for the problem
of convergecast, even if we only consider line networks. Indeed, we show that
there is no (2 -- $\epsilon$)-competitive algorithm for convergecast or for
broadcast in the class of lines, for any $\epsilon$ \textgreater{} 0.


title:
The nuclear and integrated far-infrared emission of nearby Seyfert
  galaxies

abstract:
  We present far-infrared (FIR) $70-500\,\mu$m imaging observations obtained
with Herschel/PACS and SPIRE of 33 nearby (median distance of 30 Mpc) Seyfert
galaxies from the Revised Shapley-Ames (RSA) catalogue. We obtain the FIR
nuclear ($r=1\,$kpc and $r=2\,$kpc) and integrated spectral energy
distributions (SEDs). We estimate the unresolved nuclear emission at 70 $\mu$m
and we fit the nuclear and integrated FIR SEDs with a grey body model. We find
that the integrated FIR emission of the RSA Seyferts in our sample is dominated
by emission from the host galaxy, with dust properties similar to those of
normal galaxies (non AGN). We use four criteria to select galaxies whose
nuclear $70\,\mu$m emission has a significant AGN contribution: (1) elevated
70/160 $\mu$m flux ratios, (2)spatially resolved, high dust temperature
gradient, (3) $70\,\mu$m excess emission with respect to the fit of the FIR
SEDs with a grey body, and (4) excess of nuclear SFR obtained from $70\,\mu$m
over SFR from mid-infrared indicators. 16 galaxies (48 per cent of the initial
sample) satisfy at least one of these conditions, whereas 10 satisfy half or
more. After careful examination of these, we select six bona fide candidates
(18 per cent of the initial sample) and estimate that $\sim 40-70$ per cent of
their nuclear ($r=1-2\,$kpc) $70\,\mu$m emission is contributed by dust heated
by the AGN.