title:
Investigation of the Coincidence Resolving Time performance of a PET
  scanner based on liquid xenon: A Monte Carlo study

abstract:
  The measurement of the time of flight of the two 511 keV gammas recorded in
coincidence in a PET scanner provides an effective way of reducing the random
background and therefore increases the scanner sensitivity, provided that the
coincidence resolving time (CRT) of the gammas is sufficiently good. The best
commercial PET-TOF system today (based in LYSO crystals and digital SiPMs), is
the VEREOS of Philips, boasting a CRT of 316 ps (FWHM). In this paper we
present a Monte Carlo investigation of the CRT performance of a PET scanner
exploiting the scintillating properties of liquid xenon. We find that an
excellent CRT of 70 ps (depending on the PDE of the sensor) can be obtained if
the scanner is instrumented with silicon photomultipliers (SiPMs) sensitive to
the ultraviolet light emitted by xenon. Alternatively, a CRT of 160 ps can be
obtained instrumenting the scanner with (much cheaper) blue-sensitive SiPMs
coated with a suitable wavelength shifter. These results show the excellent
time of flight capabilities of a PET device based in liquid xenon.


title:
Extremely Nonperturbative Nonlinearities in GaAs Driven by Atomically
  Strong Terahertz Fields in Gold Metamaterials

abstract:
  Terahertz near fields of gold metamaterials resonant at a frequency of
$0.88\,\rm THz$ allow us to enter an extreme limit of non-perturbative
ultrafast THz electronics: Fields reaching a ponderomotive energy in the keV
range are exploited to drive nondestructive, quasi-static interband tunneling
and impact ionization in undoped bulk GaAs, injecting electron-hole plasmas
with densities in excess of $10^{19}\,\rm cm^{-3}$. This process causes bright
luminescence at energies up to $0.5\,\rm eV$ above the band gap and induces a
complete switch-off of the metamaterial resonance accompanied by self-amplitude
modulation of transmitted few-cycle THz transients. Our results pave the way
towards highly nonlinear THz optics and optoelectronic nanocircuitry with
sub-picosecond switching times.


title:
Prediction of the higher-order terms based on Borel resummation with
  conformal mapping

abstract:
  In this paper we discuss the method of the resummation of the asymptotic
series suggested by Kazakov et al. (1978) and predictions of the higher order
terms based on this approach. Application of this method to $\varphi^4$ model
is discussed.


title:
A numerical study of two-phase flow models with dynamic capillary
  pressure and hysteresis

abstract:
  Saturation overshoot and pressure overshoot are studied by incorporating
dynamic capillary pressure, capillary pressure hysteresis and hysteretic
dynamic coefficient with a traditional fractional flow equation in one
dimension. Using the method of lines, the discretizations are constructed by
applying Castillo-Grone's mimetic operators in the space direction and explicit
trapezoidal integrator in the time direction. Convergence tests and
conservation property of the schemes are presented. Computed profiles capture
both the saturation overshoot and pressure overshoot phenomena. Comparisons
between numerical results and experiments illustrate the effectiveness and
different features of the models.


title: Measuring Unrecorded Measurement

abstract:
  Projective (Von Neumann) Measurement of an operator (i.e. a dynamical
variable) selected from a prescribed set of operators is termed unrecorded
measurement (URM) when both the selected operator and the measurement outcome
are unknown, i.e. "lost". Within classical physics a URM is completely
inconsequential: the state is unaffected by measurement. Within quantum physics
a measurement leaves a mark. The present study provides protocols that allow
retrieval of some of the data lost in a URM.


title: Lossy Kernelization

abstract:
  In this paper we propose a new framework for analyzing the performance of
preprocessing algorithms. Our framework builds on the notion of kernelization
from parameterized complexity. However, as opposed to the original notion of
kernelization, our definitions combine well with approximation algorithms and
heuristics. The key new definition is that of a polynomial size
$\alpha$-approximate kernel. Loosely speaking, a polynomial size
$\alpha$-approximate kernel is a polynomial time pre-processing algorithm that
takes as input an instance $(I,k)$ to a parameterized problem, and outputs
another instance $(I',k')$ to the same problem, such that $|I'|+k' \leq
k^{O(1)}$. Additionally, for every $c \geq 1$, a $c$-approximate solution $s'$
to the pre-processed instance $(I',k')$ can be turned in polynomial time into a
$(c \cdot \alpha)$-approximate solution $s$ to the original instance $(I,k)$.
  Our main technical contribution are $\alpha$-approximate kernels of
polynomial size for three problems, namely Connected Vertex Cover, Disjoint
Cycle Packing and Disjoint Factors. These problems are known not to admit any
polynomial size kernels unless $NP \subseteq coNP/poly$. Our approximate
kernels simultaneously beat both the lower bounds on the (normal) kernel size,
and the hardness of approximation lower bounds for all three problems. On the
negative side we prove that Longest Path parameterized by the length of the
path and Set Cover parameterized by the universe size do not admit even an
$\alpha$-approximate kernel of polynomial size, for any $\alpha \geq 1$, unless
$NP \subseteq coNP/poly$. In order to prove this lower bound we need to combine
in a non-trivial way the techniques used for showing kernelization lower bounds
with the methods for showing hardness of approximation


title: Deep Residual Networks with Exponential Linear Unit

abstract:
  Very deep convolutional neural networks introduced new problems like
vanishing gradient and degradation. The recent successful contributions towards
solving these problems are Residual and Highway Networks. These networks
introduce skip connections that allow the information (from the input or those
learned in earlier layers) to flow more into the deeper layers. These very deep
models have lead to a considerable decrease in test errors, on benchmarks like
ImageNet and COCO. In this paper, we propose the use of exponential linear unit
instead of the combination of ReLU and Batch Normalization in Residual
Networks. We show that this not only speeds up learning in Residual Networks
but also improves the accuracy as the depth increases. It improves the test
error on almost all data sets, like CIFAR-10 and CIFAR-100


title:
Effects of flake size on mode-locking behavior for flake-graphene
  saturable absorber mirrors

abstract:
  After advent of graphene as a saturable absorber many experiments have been
conducted to produce short pulse duration pulses. Here, we have measured the
properties of flake-graphene saturable absorber mirrors of various flake sizes
dependent on fabrication technique. These mirrors enabled us to obtain a large
mode-locking bandwidth of 16nm in an erbium-doped fiber laser. Mirrors with
large flake size and multi-layered thickness induce strong pulse shaping and
reflect mode-locked train of pulses with very large bandwidths.


title:
Operational Semantics of Resolution and Productivity in Horn Clause
  Logic

abstract:
  This paper presents a study of operational and type-theoretic properties of
different resolution strategies in Horn clause logic. We distinguish four
different kinds of resolution: resolution by unification (SLD-resolution),
resolution by term-matching, the recently introduced structural resolution, and
partial (or lazy) resolution. We express them all uniformly as abstract
reduction systems, which allows us to undertake a thorough comparative analysis
of their properties. To match this small-step semantics, we propose to take
Howard's System H as a type-theoretic semantic counterpart. Using System H, we
interpret Horn formulas as types, and a derivation for a given formula as the
proof term inhabiting the type given by the formula. We prove soundness of
these abstract reduction systems relative to System H, and we show completeness
of SLD-resolution and structural resolution relative to System H. We identify
conditions under which structural resolution is operationally equivalent to
SLD-resolution. We show correspondence between term-matching resolution for
Horn clause programs without existential variables and term rewriting.


title:
Single-Layered Hittorf's Phosphorus: A Wide-Bandgap High Mobility 2D
  Material

abstract:
  We propose here a two-dimensional material based on a single layer of violet
or Hittorf's phosphorus. Using first-principles density functional theory, we
find it to be energetically very stable, comparable to other previously
proposed single-layered phosphorus structures. It requires only a small
energetic cost of approximately $0.04~\text{eV/atom}$ to be created from its
bulk structure, Hittorf's phosphorus, or a binding energy of
$0.3-0.4~\text{J/m}^2$ per layer, suggesting the possibility of exfoliation in
experiments. We find single-layered Hittorf's phosphorus to be a wide band gap
semiconductor with a direct band gap of approximately $2.5$~eV and our
calculations show it is expected to have a high and highly anisotropic hole
mobility with an upper bound lying between $3000-7000$~cm$^2$V$^{-1}$s$^{-1}$.
These combined properties make single-layered Hittorf's phosphorus a very good
candidate for future applications in a wide variety of technologies, in
particular for high frequency electronics, and optoelectronic devices operating
in the low wavelength blue color range.


title:
Population synthesis of planet formation using a torque formula with
  dynamic effects

abstract:
  Population synthesis studies into planet formation have suggested that
distributions consistent with observations can only be reproduced if the actual
Type I migration timescale is at least an order of magnitude longer than that
deduced from linear theories. Although past studies considered the effect of
the Type I migration of protoplanetary embryos, in most cases they used a
conventional formula based on static torques in isothermal disks, and employed
a reduction factor to account for uncertainty in the mechanism details.
However, in addition to static torques, a migrating planet experiences dynamic
torques that are proportional to the migration rate. These dynamic torques can
impact on planet migration and predicted planetary populations. In this study,
we derived a new torque formula for Type I migration by taking into account
dynamic corrections. This formula was used to perform population synthesis
simulations with and without the effect of dynamic torques. In many cases,
inward migration was slowed significantly by the dynamic effects. For the
static torque case, gas giant formation was effectively suppressed by Type I
migration; however, when dynamic effects were considered, a substantial
fraction of cores survived and grew into gas giants.


title:
Rigidity of spacelike hypersurfaces in spatially weighted generalized
  Robertson-Walker spacetimes

abstract:
  Our purpose in this paper is to apply some maximum principles in order to
study the rigidity of complete spacelike hypersurfaces immersed in a spatially
weighted generalized Robertson-Walker (GRW) spacetime, which is supposed to
obey the so called strong null convergence condition. Under natural constraints
on the weight function and on the f-mean curvature, we establish sufficient
conditions to guarantee that such a hypersurface must be a slice of the ambient
space. In this setting, we also obtain new Calabi-Bernstein type results
concerning entire graphs in a spatially weighted GRW spacetime.


title:
Relation between trees of fragmenting granules and supergranulation
  evolution

abstract:
  Context: The determination of the underlying mechanisms of the magnetic
elements diffusion over the solar surface is still a challenge. Understanding
the formation and evolution of the solar network (NE) is a challenge, because
it provides a magnetic flux over the solar surface comparable to the flux of
active regions at solar maximum. Aims: We investigate the structure and
evolution of interior cells of solar supergranulation. From Hinode
observations, we explore the motions on solar surface at high spatial and
temporal resolution. We derive the main organization of the flows inside
supergranules and their effect on the magnetic elements. Method: To probe the
superganule interior cell, we used the Trees of Fragmenting Granules (TFG)
evolution and their relations to horizontal Results: Evolution of TFG and their
mutual interactions result in cumulative effects able to build horizontal
coherent flows with longer lifetime than granulation (1 to 2 hours) over a
scale up to 12\arcsec. These flows clearly act on the diffusion of the
intranetwork (IN) magnetic elements and also on the location and shape of the
network. Conclusions: From our analysis during 24 hours, TFG appear as one of
the major elements of the supergranules which diffuse and advect the magnetic
field on the Sun's surface. The strongest supergranules contribute the most to
magnetic flux diffusion in the solar photosphere.


title:
Geometric implications of the M(r,s)-properties and the uniform
  Kadec-Klee property in JB*-triples

abstract:
  We explore new implications of the $M(r,s)$ and $M^*(r,s)$ properties for
Banach spaces. We show that a Banach space $X$ satisfying property $M(1,s)$ for
some $0<s\leq 1$, admitting a point $x_{0}$ in its unit sphere at which the
relative weak and norm topologies agree, satisfies the generalized Gossez-Lami
Dozo property. We establish sufficient conditions, in terms of the $(r,
s)$-Lipschitz weak$^*$ Kadec-Klee property on a Banach space $X$, to guarantee
that its dual space satisfies the UKK$^*$ property. We determine appropriate
conditions to assure that a Banach space $X$ satisfies the $(r, s)$-Lipschitz
weak$^*$ Kadec-Klee property. These results are applied to prove that every
spin factor satisfies the UKK property, and consequently, the KKP and the UKK
properties are equivalent for real and complex JB$^*$-triples.


title:
An Identity Involving Integration with Respect to Variable Order of
  Fractional Derivative

abstract:
  In 1993, Samko and Ross introduced the study of fractional integration and
differentiation when the order is not a constant but a function. This
suggestion gave rise to a number of further ideas and results. In particular,
this implies a possibility of integration with respect to derivative's order.
Here an identity is presented, in which an expression involving
Riemann--Liouville fractional derivative is integrated with respect to the
derivative's order.


title: Towards a symplectic version of the Chevalley restriction theorem

abstract:
  If $(G,V)$ is a polar representation with Cartan subspace $\mathfrak c$ and
Weyl group $W$, it is shown that there is a natural morphism of Poisson schemes
$\mathfrak c \oplus {\mathfrak c}^*/W \to V\oplus V^*/\!\!/\!\!/ G$. This
morphism is conjectured to be an isomorphism of the underlying reduced
varieties if $(G,V)$ is visible. The conjecture is proved for visible stable
locally free polar representations and certain further examples.


title: North Galactic plane structure with IPHAS Be stars

abstract:
  Our goal is to investigate the spiral structure of the Northern Galactic
plane using as tracers the classical Be stars detected by INT Photometric
H$\alpha$ Survey (IPHAS). IPHAS scans the $29^o<l<+215^o, -5^o<b<+5^o$ region
in the $r$, $i$ and H$\alpha$ bands. Spectroscopic follow up has been done for
the bright H$\alpha$ emitters. We have developed an automatic procedure for
spectral analysis, based on the BCD spectrophotometric system. In this paper we
present a cataloque of 1135 Classical Be stars, for which we have determined
spectral types, astrophysical parameters and distances. From these results we
make a first attempt to map the structure of the Galactic disk in the
anticenter direction.


title:
The Critical Numbers of Rankin-Selberg Convolutions of Cohomological
  Representations

abstract:
  We study the critical numbers of the Rankin-Selberg convolution of arbitrary
pairs of cohomological cuspidal automorphic representations and we parametrize
these critical numbers by certain 1-dimensional subrepresentations attached to
the corresponding pair of finite-dimensional representations of the related
general linear groups.


title: ExB mean flows in finite ion temperature plasmas

abstract:
  The impact of ion pressure dynamics on E x B mean flows is investigated.
Using a simplified, two-dimensional, drift ordered fluid model in the
thin-layer approximation, three stresses in addition to the Reynolds stress are
shown to modify the E x B mean flow. These additional terms in the stress
tensor all require ion pressure fluctuations. Quasi-linear analysis show that
these additional stresses are as important as the Reynolds stress, and hence
must be taken into account in analysis of transport barriers in which sheared E
x B mean flows are key ingredients.


title: Filling in the details: Perceiving from low fidelity images

abstract:
  Humans perceive their surroundings in great detail even though most of our
visual field is reduced to low-fidelity color-deprived (e.g. dichromatic) input
by the retina. In contrast, most deep learning architectures are
computationally wasteful in that they consider every part of the input when
performing an image processing task. Yet, the human visual system is able to
perform visual reasoning despite having only a small fovea of high visual
acuity. With this in mind, we wish to understand the extent to which
connectionist architectures are able to learn from and reason with low acuity,
distorted inputs. Specifically, we train autoencoders to generate full-detail
images from low-detail "foveations" of those images and then measure their
ability to reconstruct the full-detail images from the foveated versions. By
varying the type of foveation, we can study how well the architectures can cope
with various types of distortion. We find that the autoencoder compensates for
lower detail by learning increasingly global feature functions. In many cases,
the learnt features are suitable for reconstructing the original full-detail
image. For example, we find that the networks accurately perceive color in the
periphery, even when 75\% of the input is achromatic.


title:
$\phi$-parabolicity and the uniqueness of spacelike hypersurfaces
  immersed in a spatially weighted GRW spacetime

abstract:
  In this paper, we extend a technique due to Romero, Rubio and Salamanca
establishing sufficient conditions to guarantee the parabolicity of complete
spacelike hypersurfaces immersed in a weighted generalized Robertson-Walker
spacetime whose fiber has phi-parabolic universal Riemannian covering. As some
applications of this criteria, we obtain uniqueness results concerning
spacelikes hypersurfaces immersed in spatially weighted generalized
Robertson-Walker spacetimes. Furthermore, Calabi-Bernstein type results are
also given.


title:
A Chandra Study of the Image Power Spectra of 41 Cool Core and Non-Cool
  Core Galaxy Clusters

abstract:
  In this work we propose a new diagnostic to segregate cool core (CC) clusters
from non-cool core (NCC) clusters by studying the two-dimensional power spectra
of the X-ray images observed with the Chandra X-ray observatory. Our sample
contains 41 members ($z=0.01\sim 0.54$), which are selected from the Chandra
archive when a high photon count, an adequate angular resolution, a relatively
complete detector coverage, and coincident CC-NCC classifications derived with
three traditional diagnostics are simultaneously guaranteed. We find that in
the log-log space the derived image power spectra can be well represented by a
constant model component at large wavenumbers, while at small wavenumbers a
power excess beyond the constant component appears in all clusters, with a
clear tendency that the excess is stronger in CC clusters. By introducing a new
CC diagnostic parameter, i.e., the power excess index (PEI), we classify the
clusters in our sample and compare the results with those obtained with three
traditional CC diagnostics. We find that the results agree with each other very
well. By calculating the PEI values of the simulated clusters, we find that the
new diagnostic works well at redshifts up to 0.5 for intermediately sized and
massive clusters with a typical Chandra or XMM pointing observation. The new CC
diagnostic has several advantages over its counterparts, e.g., it is free of
the effects of the commonly seen centroid shift of the X-ray halo caused by
merger event, and the corresponding calculation is straightforward, almost
irrelevant to the complicated spectral analysis.


title:
A measurement method of a detector response function for monochromatic
  electrons based on the Compton scattering

abstract:
  In this paper we present a method of scintillation detector energy
calibration using the gamma-rays. The technique is based on the Compton
scattering of gamma-rays in a scintillation detector and subsequent
photoelectric absorption of the scattered photon in the Ge-detector. The
novelty of this method is that the source of gamma rays, the germanium and
scintillation detectors are immediately arranged adjacent to each other. The
method presents an effective solution for the detectors consisting of a low
atomic number materials, when the ratio between Compton effect and
photoelectric absorption is large and the mean path of gamma-rays is comparable
to the size of the detector. The technique can be used for the precision
measurements of the scintillator light yield dependence on the electron energy.


title: Extinction properties of multi-type continuous-state branching processes

abstract:
  Recently in Barczy, Li and Pap (2015), the notion of a multi-type
continuous-state branching process (with immigration) having d-types was
introduced as a solution to an d-dimensional vector- valued SDE. Preceding
that, work on affine processes, originally motivated by math- ematical finance,
in Duffie, Filipovic and Schachermayer (2003) also showed the existence of such
processes. See also more recent contributions in this direction due to
Gabrielli and Teichmann (2014) and Caballero, Perez Garmendia and Uribe Bravo
(2015). Older work on multi-type continuous-state branching processes is more
sparse but includes Watanabe (1969) and Ma (2013), where only two types are
considered. In this paper we take a completely different approach and consider
multi-type continuous-state branching process, now allowing for up to a
countable infinity of types, defined instead as a super Markov chain with both
local and non-local branching mechanisms. In the spirit of Englander and
Kyprianou (2004) we explore their extinction properties and pose a number of
open problems.


title: Study of Glass and Bakelite properties as electrodes in RPCs

abstract:
  India-based Neutrino Observatory (INO) collaboration is planning to build a
magnetized Iron-CALorimeter detector (ICAL) for the study of atmospheric
neutrinos. ICAL detector will be a stack of 151 layers of magnetized iron
plates interleaved with Resistive Plate Chambers (RPCs) as active detector
elements with a total mass of 50 kton. Resistive Plate Chambers are gaseous
detectors made up of two parallel electrodes of high bulk resistivity like
float glass and bakelite. These detectors are extensively used in several high
energy physics experiments since 1980s because of high count rate, excellent
time as well as spatial resolutions, simple to fabricate and operate. Due to
detector aging issue, it is necessary to characterize electrode material so as
to select appropriate electrode material before fabricating the detector. In
the present studies, we measured bulk resistivity and surface current of glass
as well as bakelite. Bulk resistivity of bakelite is ~ 100 times less than that
of glass and surface current of bakelite is higher than that of glass. Also
glass does not need any kind of surface treatment to achieve better surface
uniformity. Therefore, glass electrodes are preferred over bakelite electrodes
in most of the cases. Locally manufactured Asahi glass of ~2 mm thickness and
bakelite sheets were tested during the studies as reported in this paper before
the various stages of detector fabrication.


title:
Isometric embedding of $\ell_1$ into Lipschitz-free spaces and
  $\ell_\infty$ into their duals

abstract:
  We show that the dual of every infinite-dimensional Lipschitz-free Banach
space contains an isometric copy of $\ell_\infty$ and that it is often the case
that a Lipschitz-free Banach space contains a $1$-complemented subspace
isometric to $\ell_1$. Even though we do not know whether the latter is true
for every infinite-dimensional Lipschitz-free Banach space, we show that the
space is never rotund.
  Further, in the last section we survey the relations between "isometric
embedding of~$\ell_\infty$ into the dual" and "containing as good copy
of~$\ell_1$ as possible" in a general Banach space.


title:
Tidal wave in $^{102}$Pd: An extended five-dimensional collective
  Hamiltonian description

abstract:
  The five-dimensional collective Hamiltonian based on the covariant density
functional theory is applied to investigate the observed tidal wave mode in the
yrast band of $^{102}$Pd. The energy spectra, the relations between the spin
and the rotational frequency, and the ratios of $B(E2)/\mathcal{J}(I)$ in the
yrast band are well reproduced by introducing the empirical $ab$ formula for
the moments of inertia. This $ab$ formula is related to the fourth order effect
of collective momentum in the collective Hamiltonian. It is also shown that the
shape evolution in the tidal wave is determined microscopically by the
competition between the rotational kinetic energy and the collective potential
in the framework of the collective Hamiltonian.


title: Scaling Theory of the Mechanical Properties of Amorphous Nano-Films

abstract:
  Numerical Simulations are employed to create amorphous nano-films of a chosen
thickness on a crystalline substrate which induces strain on the film. The
films are grown by a vapor deposition technique which was recently developed to
create very stable glassy films. Using the exact relations between the Hessian
matrix and the shear and bulk moduli we explore the mechanical properties of
the nano-films as a function of the density of the substrate and the film
thickness. The existence of the substrate dominates the mechanical properties
of the combined substrate-film system. Scaling concepts are then employed to
achieve data collapse in a wide range of densities and film thicknesses.


title:
On The splitting of the Einstein field equations with respect to a
  general $(1 + 3)$ threading of spacetime

abstract:
  Based on a general $(1+3)$ threading of the spacetime $(M,g)$, we obtain a
new and simple splitting of a both the Einstein field equations (EFE) and the
conservation laws in $(M,g)$. As an application we obtain the splitting of
(EFE) in an almost FLRW universe with energy-momentum tensor of a perfect
fluid. In particular, we state the perturbation Friedman equations in an almost
FLRW universe.


title: Fast and oblivious algorithms for dissipative and 2D wave equations

abstract:
  The use of time-domain boundary integral equations has proved very effective
and efficient for three dimensional acoustic and electromagnetic wave
equations. In even dimensions and when some dissipation is present, time-domain
boundary equations contain an infinite memory tail. Due to this, computation
for longer times becomes exceedingly expensive. In this paper we show how
oblivious quadrature, initially designed for parabolic problems, can be used to
significantly reduce both the cost and the memory requirements of computing
this tail. We analyse Runge-Kutta based quadrature and conclude the paper with
numerical experiments.


title:
Quantum oscillator and Kepler-Coulomb problems in curved spaces:
  deformed shape invariance, point canonical transformations, and rational
  extensions

abstract:
  The quantum oscillator and Kepler-Coulomb problems in $d$-dimensional spaces
with constant curvature are analyzed from several viewpoints. In a deformed
supersymmetric framework, the corresponding nonlinear potentials are shown to
exhibit a deformed shape invariance property. By using the point canonical
transformation method, the two deformed Schr\"odinger equations are mapped onto
conventional ones corresponding to some shape-invariant potentials, whose
rational extensions are well known. The inverse point canonical transformations
then provide some rational extensions of the oscillator and Kepler-Coulomb
potentials in curved space. The oscillator on the sphere and the Kepler-Coulomb
potential in a hyperbolic space are studied in detail and their extensions are
proved to be consistent with already known ones in Euclidean space. The
partnership between nonextended and extended potentials is interpreted in a
deformed supersymmetric framework. Those extended potentials that are
isospectral to some nonextended ones are shown to display deformed shape
invariance, which in the Kepler-Coulomb case is enlarged by also translating
the degree of the polynomial arising in the rational part denominator.


title: Autonomous Scanning for Endomicroscopic Mosaicing and 3D Fusion

abstract:
  Robotic-assisted Minimally Invasive Surgery (RMIS) can benefit from the
automation of common, repetitive or well-defined but ergonomically difficult
tasks. One such task is the scanning of a pick-up endomicroscopy probe over a
complex, undulating tissue surface in order to enhance the effective
field-of-view through video mosaicing. In this paper, the da Vinci surgical
robot, through the dVRK framework, is used for autonomous scanning and 2D
mosaicing over a user-defined region of interest. To achieve the level of
precision required for high quality large-area mosaic generation, which relies
on sufficient overlap between consecutive image frames, visual servoing is
performed using a tracking marker attached to the probe. The resulting
sub-millimetre accuracy of the probe motion allows for the generation of large
endomicroscopy mo- saics with minimal intervention from the surgeon. It also
allows the probe to be maintained in an orientation perpendicular to the local
tissue surface, providing optimal imaging results. Images are streamed from the
endomicroscope and overlaid live onto the surgeons view, while 2D mosaics are
generated in real-time, and fused into a 3D stereo reconstruction of the
surgical scene, thus providing intuitive visualisation and fusion of the
multi-scale images. The system therefore offers significant potential to
enhance surgical procedures, by providing the operator with cellular-scale
information over a larger area than could typically be achieved by manual
scanning.


title:
An Improved Discrete Bat Algorithm for Symmetric and Asymmetric
  Traveling Salesman Problems

abstract:
  Bat algorithm is a population metaheuristic proposed in 2010 which is based
on the echolocation or bio-sonar characteristics of microbats. Since its first
implementation, the bat algorithm has been used in a wide range of fields. In
this paper, we present a discrete version of the bat algorithm to solve the
well-known symmetric and asymmetric traveling salesman problems. In addition,
we propose an improvement in the basic structure of the classic bat algorithm.
To prove that our proposal is a promising approximation method, we have
compared its performance in 37 instances with the results obtained by five
different techniques: evolutionary simulated annealing, genetic algorithm, an
island based distributed genetic algorithm, a discrete firefly algorithm and an
imperialist competitive algorithm. In order to obtain fair and rigorous
comparisons, we have conducted three different statistical tests along the
paper: the Student's $t$-test, the Holm's test, and the Friedman test. We have
also compared the convergence behaviour shown by our proposal with the ones
shown by the evolutionary simulated annealing, and the discrete firefly
algorithm. The experimentation carried out in this study has shown that the
presented improved bat algorithm outperforms significantly all the other
alternatives in most of the cases.


title: Logic for Unambiguous Context-Free Languages

abstract:
  We give in this paper a logical characterization for unambiguous Context Free
Languages, in the vein of descriptive complexity. A fragment of the logic
characterizing context free languages given by Lautemann, Schwentick and
Th\'erien [18] based on implicit definability is used for this aim. We obtain a
new connection between two undecidable problems, a logical one and a language
theoretical one.


title: Multivariate P-Eulerian polynomials

abstract:
  The P-Eulerian polynomial counts the linear extensions of a labeled partially
ordered set, P, by their number of descents. It is known that the P-Eulerian
polynomials are real-rooted for various classes of posets P. The purpose of
this paper is to extend these results to polynomials in several variables. To
this end we study multivariate extensions of P-Eulerian polynomials and prove
that for certain posets these polynomials are stable, i.e., non-vanishing
whenever all variables are in the upper half-plane of the complex plane. A
natural setting for our proofs is the Malvenuto-Reutenauer algebra of
permutations (or the algebra of free quasi-symmetric functions). In the process
we identify an algebra on Dyck paths, which to our knowledge has not been
studied before.


title: On a determinantal inequality arising from diffusion tensor imaging

abstract:
  In comparing geodesics induced by different metrics, Audenaert formulated the
following determinantal inequality
  $$\det(A^2+|BA|)\le \det(A^2+AB),$$ where $A, B$ are $n\times n$ positive
semidefinite matrices. We complement his result by proving
  $$\det(A^2+|AB|)\ge \det(A^2+AB).$$ Our proofs feature the fruitful interplay
between determinantal inequalities and majorization relations. Some related
questions are mentioned.


title:
On Reducing the Number of Visual Words in the Bag-of-Features
  Representation

abstract:
  A new class of applications based on visual search engines are emerging,
especially on smart-phones that have evolved into powerful tools for processing
images and videos. The state-of-the-art algorithms for large visual content
recognition and content based similarity search today use the "Bag of Features"
(BoF) or "Bag of Words" (BoW) approach. The idea, borrowed from text retrieval,
enables the use of inverted files. A very well known issue with this approach
is that the query images, as well as the stored data, are described with
thousands of words. This poses obvious efficiency problems when using inverted
files to perform efficient image matching. In this paper, we propose and
compare various techniques to reduce the number of words describing an image to
improve efficiency and we study the effects of this reduction on effectiveness
in landmark recognition and retrieval scenarios. We show that very relevant
improvement in performance are achievable still preserving the advantages of
the BoF base approach.


title:
A second order local minimality criterion for the triple junction
  singularity of the Mumford-Shah functional

abstract:
  This paper is the first part of an ongoing project aimed at providing a local
minimality criterion, based on a second variation approach, for the triple
point configurations of the Mumford-Shah functional.


title:
Self-taught learning of a deep invariant representation for visual
  tracking via temporal slowness principle

abstract:
  Visual representation is crucial for a visual tracking method's performances.
Conventionally, visual representations adopted in visual tracking rely on
hand-crafted computer vision descriptors. These descriptors were developed
generically without considering tracking-specific information. In this paper,
we propose to learn complex-valued invariant representations from tracked
sequential image patches, via strong temporal slowness constraint and stacked
convolutional autoencoders. The deep slow local representations are learned
offline on unlabeled data and transferred to the observational model of our
proposed tracker. The proposed observational model retains old training samples
to alleviate drift, and collect negative samples which are coherent with
target's motion pattern for better discriminative tracking. With the learned
representation and online training samples, a logistic regression classifier is
adopted to distinguish target from background, and retrained online to adapt to
appearance changes. Subsequently, the observational model is integrated into a
particle filter framework to peform visual tracking. Experimental results on
various challenging benchmark sequences demonstrate that the proposed tracker
performs favourably against several state-of-the-art trackers.


title:
A coalescent dual process for a Wright-Fisher diffusion with
  recombination and its application to haplotype partitioning

abstract:
  Duality plays an important role in population genetics. It can relate results
from forwards-in-time models of allele frequency evolution with those of
backwards-in-time genealogical models; a well known example is the duality
between the Wright-Fisher diffusion for genetic drift and its genealogical
counterpart, the coalescent. There have been a number of articles extending
this relationship to include other evolutionary processes such as mutation and
selection, but little has been explored for models also incorporating crossover
recombination. Here, we derive from first principles a new genealogical process
which is dual to a Wright-Fisher diffusion model of drift, mutation, and
recombination. Our approach is based on expressing a putative duality
relationship between two models via their infinitesimal generators, and then
seeking an appropriate test function to ensure the validity of the duality
equation. This approach is quite general, and we use it to find dualities for
several important variants, including both a discrete L-locus model of a gene
and a continuous model in which mutation and recombination events are scattered
along the gene according to continuous distributions. As an application of our
results, we derive a series expansion for the transition function of the
diffusion. Finally, we study in further detail the case in which mutation is
absent. Then the dual process describes the dispersal of ancestral genetic
material across the ancestors of a sample. The stationary distribution of this
process is of particular interest; we show how duality relates this
distribution to haplotype fixation probabilities. We develop an efficient
method for computing such probabilities in multilocus models.


title:
A Discrete Firefly Algorithm to Solve a Rich Vehicle Routing Problem
  Modelling a Newspaper Distribution System with Recycling Policy

abstract:
  A real-world newspaper distribution problem with recycling policy is tackled
in this work. In order to meet all the complex restrictions contained in such a
problem, it has been modeled as a rich vehicle routing problem, which can be
more specifically considered as an asymmetric and clustered vehicle routing
problem with simultaneous pickup and deliveries, variable costs and forbidden
paths (AC-VRP-SPDVCFP). This is the first study of such a problem in the
literature. For this reason, a benchmark composed by 15 instances has been also
proposed. In the design of this benchmark, real geographical positions have
been used, located in the province of Bizkaia, Spain. For the proper treatment
of this AC-VRP-SPDVCFP, a discrete firefly algorithm (DFA) has been developed.
This application is the first application of the firefly algorithm to any rich
vehicle routing problem. To prove that the proposed DFA is a promising
technique, its performance has been compared with two other well-known
techniques: an evolutionary algorithm and an evolutionary simulated annealing.
Our results have shown that the DFA has outperformed these two classic
meta-heuristics.


title: Transport in Sawtooth photonic lattices

abstract:
  We investigate, theoretically and experimentally, a photonic realization of a
Sawtooth lattice. This special lattice exhibits two spectral bands, with one of
them experiencing a complete collapse to a highly degenerate flat band for a
special set of inter-site coupling constants. We report the ob- servation of
different transport regimes, including strong transport inhibition due to the
appearance of the non-diffractive flat band. Moreover, we excite localized
Shockley surfaces states, residing in the gap between the two linear bands.


title: Efficient Counting of Degree Sequences

abstract:
  Novel dynamic programming algorithms to count the set $D(n)$ of zero-free
degree sequences of length $n$, the set $D_c(n)$ of degree sequences of
connected graphs on $n$ vertices and the set $D_b(n)$ of degree sequences of
biconnected graphs on $n$ vertices exactly are presented. They are all based on
a recurrence of Barnes and Savage and shown to run in polynomial time and are
asymptotically much faster than the previous best known algorithms for these
problems. These appear to be the first polynomial time algorithms to compute
$|D(n)|$, $|D_c(n)|$ and $|D_b(n)|$ to the author's knowledge and have enabled
us to tabulate them up to $n=118$, the majority of which were unknown. The
available numerical results of $|D(n)|$ tend to give more supporting evidence
of a conjecture of Gordon F. Royle about the limit of $|D(n)|/|D(n-1)|$. The
OEIS entries that can be computed by algorithms in this paper are A004251,
A007721, A007722 and A095268.


title: Voynich Manuscript or Book of Dunstan coding and decoding methods

abstract:
  The Voynich manuscript is the book initially dated as fifteenth century book.
It written using specific and smart coding methods. This article describes the
methods how it was analyzed and how coding keys were found. The last manuscript
page decoding. Correlation of the last VMS page content with John Dee notes
dedicated to 12th of December 1587. The proof that the Voynich manuscript and
the "Book of Dunstan" - the same manuscripts. This article contains Engish
version(pages 1-86) and equal Russian (pages 87 - 192) version. The new chapter
(#13) is dedicated to Christian symbolics in VMS as well as for the solution of
the riddle of 3 queens in astrological part and the riddle of diagram with 2
cancers (red and white) as additional proof of John Dee authorship of
manuscript.


title: Short time dynamics of water coalescence on a flat water pool

abstract:
  Coalescence is an important hydrodynamic event that frequently takes place in
nature as well as in industry. Here we provide an experimental study on short
time dynamics of water coalescence, particularly when a water droplet comes in
contact with a flat water surface, by utilizing high-resolution
high-penetration ultrafast X-ray microscopy. Our results demonstrate a
possibility that an extreme curvature difference between a drop and a flat
surface can significantly modify the hydrodynamics of water coalescence, which
is unexpected in the existing theory. We suggest a plausible explanation for
why coalescence can be modified by an extreme curvature difference.


title:
NGC6362: the least massive globular cluster with chemically distinct
  multiple populations

abstract:
  We present the first measure of Fe and Na abundances in NGC 6362, a low-mass
globular cluster where first and second generation stars are fully spatially
mixed. A total of 160 member stars (along the red giant branch and the red
horizontal branch) have been observed with the multi-object spectrograph FLAMES
at the Very Large Telescope. We find that the cluster has an iron abundance of
[Fe/H]=--1.09$\pm$0.01 dex, without evidence of intrinsic dispersion. On the
other hand, the [Na/Fe] distribution turns out to be intrinsically broad and
bimodal. The Na-poor and Na-rich stars populate, respectively, the bluest and
the reddest red giant branches detected in the color-magnitude diagrams
including the U filter. The red giant branch is composed of a mixture of first
and second generation stars in a similar proportion, while almost all the red
horizontal branch stars belong to the first cluster generation. Until now, NGC
6362 is the least massive globular cluster where both the photometric and
spectroscopic signatures of multiple populations have been detected.


title:
About the possible signature of pion bose condensation contribution in
  the high energy cosmic ray nuclear interactions

abstract:
  The events of anomalous energy deposit and high number of hadrons in hadron
calorimeter, often not accompanied at all, or accompanied by very small EAS of
cosmic rays, are observed by means of the complex installation aimed at
research of cosmic rays. The data quoted and their analysis point to the real
contribution and the essential role of pion Bose condensation in high energy
nuclear interactions. The possibility of the existence of such process in the
nuclear matter (in the neutron stars and in some kinds of the nuclei) was
proposed by A.B.Migdal in 1971.


title: Learning to Generate Genotypes with Neural Networks

abstract:
  Neural networks and evolutionary computation have a rich intertwined history.
They most commonly appear together when an evolutionary algorithm optimises the
parameters and topology of a neural network for reinforcement learning
problems, or when a neural network is applied as a surrogate fitness function
to aid the evolutionary optimisation of expensive fitness functions. In this
paper we take a different approach, asking the question of whether a neural
network can be used to provide a mutation distribution for an evolutionary
algorithm, and what advantages this approach may offer? Two modern neural
network models are investigated, a Denoising Autoencoder modified to produce
stochastic outputs and the Neural Autoregressive Distribution Estimator.
Results show that the neural network approach to learning genotypes is able to
solve many difficult discrete problems, such as MaxSat and HIFF, and regularly
outperforms other evolutionary techniques.


title:
Robust Control Framework for Time-Varying Power-Sharing among
  Distributed Energy Resources

abstract:
  One of the most important challenges facing an electric grid is to
incorporate renewables and distributed energy resources (DERs) to the grid.
Because of the associated uncertainties in power generations and peak power
demands, opportunities for improving the functioning and reliability of the
grid lie in the design of an efficient, yet pragmatic distributed control
framework with guaranteed robustness margins. This paper addresses the problem
of output voltage regulation for multiple DC-DC converters connected to a grid,
and prescribes a robust scheme for sharing power among different sources. More
precisely, we develop a control architecture where, unlike most standard
control frameworks, the desired power ratios appear as reference signals to
individual converter systems, and not as internal parameters of the system of
parallel converters. This makes the proposed approach suited for scenarios when
the desired power ratios vary rapidly with time. Additionally, the proposed
control framework is suitable to both centralized and decentralized
implementations, i.e., the same control architecture can be employed for
voltage regulation irrespective of the availability of common load-current (or
power) measurement, without the need to modify controller parameters. The
control design is obtained using robust optimal-control framework. Case studies
presented show the enhanced performance of prescribed optimal controllers for
voltage regulation and power sharing.


title:
Dynamics on networks: competition of temporal and topological
  correlations

abstract:
  Links in many real-world networks activate and deactivate in correspondence
to the sporadic interactions between the elements of the system. The activation
patterns may be irregular or bursty and play an important role on the dynamics
of processes taking place in the network. Information or disease spreading in
networks are paradigmatic examples of this situation. Besides burstiness,
several correlations may appear in the process of link activation: memory
effects imply temporal correlations, but also the existence of communities in
the network may mediate the activation patterns of internal an external links.
Here we study the competition of topological and temporal correlations in link
activation and how they affect the dynamics of systems running on the network.
Interestingly, both types of correlations by separate have opposite effects:
one (topological) delays the dynamics of processes on the network, while the
other (temporal) accelerates it. When they occur together, our results show
that the direction and intensity of the final outcome depends on the
competition in a non trivial way.


title:
On statistical properties for equilibrium states of partially hyperbolic
  horseshoes

abstract:
  We derive some statistical properties for equilibrium states of partially
hyperbolic horseshoes. We define a projection map associated to the horseshoe
and prove a spectral gap for its transfer operator acting on the space of
H\"older continuous observables. From this we deduce an exponential decay of
correlations and a central limit theorem. We finally extend these results to
the horseshoe.


title: Note on VCG vs. Price Raising for Matching Markets

abstract:
  In \cite{EK10} the use of VCG in matching markets is motivated by saying that
in order to compute market clearing prices in a matching market, the auctioneer
needs to know the true valuations of the bidders. Hence VCG and corresponding
personalized prices are proposed as an incentive compatible mechanism. The same
line of argument pops up in several lecture sheets and other documents related
to courses based on Easley and Kleinberg's book, seeming to suggest that
computing market clearing prices and corresponding assignments were \emph{not}
incentive compatible. Main purpose of our note is to observe that, in contrast,
assignments based on buyer optimal market clearing prices are indeed incentive
compatible.


title: Optimal Sensor Scheduling for Multiple Linear Dynamical Systems

abstract:
  We consider the design of an optimal collision-free sensor schedule for a
number of sensors which monitor different linear dynamical systems
correspondingly. At each time, only one of all the sensors can send its local
estimate to the remote estimator. A preliminary work for the two-sensor
scheduling case has been studied in the literature. The generalization into
multiple-sensor scheduling case is shown to be nontrivial. We first find a
necessary condition of the optimal solution provided that the spectral radii of
any two system matrices are not equal, which can significantly reduce the
feasible optimal solution space without loss of performance. By modelling a
finite-state Markov decision process (MDP) problem, we can numerically search
an asymptotic periodic schedule which is proven to be optimal. From a practical
viewpoint, the computational complexity is formidable for some special system
models, e.g., the spectral radii of some certain system matrices are far from
others'. Some simple but effective suboptimal schedules for any systems are
proposed. We also find a lower bound of the optimal cost, which enables us to
quantify the performance gap between any suboptimal schedule and the optimal
one.


title:
Statistics of Infima and Stopping Times of Entropy Production and
  Applications to Active Molecular Processes

abstract:
  We study the statistics of infima, stopping times and passage probabilities
of entropy production in nonequilibrium steady states, and show that they are
universal. We consider two examples of stopping times: first-passage times of
entropy production and waiting times of stochastic processes, which are the
times when a system reaches for the first time a given state. Our main results
are: (i) the distribution of the global infimum of entropy production is
exponential with mean equal to minus Boltzmann's constant; (ii) we find the
exact expressions for the passage probabilities of entropy production to reach
a given value; (iii) we derive a fluctuation theorem for stopping-time
distributions of entropy production. These results have interesting
implications for stochastic processes that can be discussed in simple colloidal
systems and in active molecular processes. In particular, we show that the
timing and statistics of discrete chemical transitions of molecular processes,
such as, the steps of molecular motors, are governed by the statistics of
entropy production. We also show that the extreme-value statistics of active
molecular processes are governed by entropy production, for example, the
infimum of entropy production of a motor can be related to the maximal
excursion of a motor against the direction of an external force. Using this
relation, we make predictions for the distribution of the maximum backtrack
depth of RNA polymerases, which follows from our universal results for
entropy-production infima.


title:
First principles calculation and experimental investigation of lattice
  dynamics in the rare earth pyrochlores R2Ti2O7 (R=Tb, Dy, Ho)

abstract:
  We present a model of the lattice dynamics of the rare earth titanate
pyrochlores R2Ti2O7 (R=Tb, Dy, Ho), which are important materials in the study
of frustrated magnetism. The phonon modes are obtained by density functional
calculations, and these predictions are verified by comparison with scattering
experiments. Single crystal inelastic neutron scattering is used to measure
acoustic phonons along high symmetry directions for R=Tb, Ho; single crystal
inelastic x-ray scattering is used to measure numerous optical modes throughout
the Brillouin zone for R=Ho; and powder inelastic neutron scattering is used to
estimate the phonon density of states for R=Tb, Dy, Ho. Good agreement between
the calculations and all measurements is obtained, allowing confident
assignment of the energies and symmetries of the phonons in these materials
under ambient conditions. The knowledge of the phonon spectrum is important for
understanding spin-lattice interactions, and can be expected to be transferred
readily to other members of the series to guide the search for unconventional
magnetic excitations.


title: Kinetic effects in diffusion on a disordered square lattice

abstract:
  In this work, the effect of fluctuations in a disordered square lattice on
diffusion of a test particle is studied using kinetic Monte Carlo simulations.
Diffusion is relevant to a wide variety of problems, both within physics and
outside of physics. Kinetic effects in diffusion are often hidden in a
thermodynamical description of the problem. In this work, no assumptions based
on energy are made, and diffusion occurs purely based on the attempt rate of
the test particle and the occupation and fluctuation rate of the lattice.
Although the average transition rate of the particle is the same for a static
or fluctuating lattice with specific occupation, the diffusion constant is
kinetically affected in a fluctuating, disordered lattice. If the lattice
fluctuates faster than the attempt rate of the particle, diffusion is
controlled by the attempt rate of the particle. However, if the lattice
fluctuates slower than the attempt rate of the particle, diffusion is affected
by the fluctuations. The slower the lattice fluctuates, the lower the diffusion
constant. Furthermore, it is found that for fast fluctuating lattices,
diffusion is due to Brownian motion. If the lattice fluctuates slower than the
particle, diffusion becomes anomalous depending on the occupation of the
lattice.

categories: cond-mat.stat-mech cond-mat.mtrl-sci cond-mat.other physics.comp-ph


title: Commensurated subgroups in tree almost automorphism groups

abstract:
  We prove that the tree almost automorphism groups admit exactly three
commensurability classes of closed commensurated subgroups. Our proof utilizes
an independently interesting characterization of subgroups of the tree almost
automorphism groups which contain only periodic elements in terms of the
dynamics of the action on the boundary of the tree. Our results further cover
several interesting finitely generated subgroups of the tree almost
automorphism groups, including the Thompson groups $F$, $T$, and $V$. We show
in particular that Thompson's group $T$ has no commensurated subgroups other
than the finite subgroups and the entire group. As a consequence, we derive
several rigidity results for the possible embeddings of these groups into
locally compact groups.


title: Conical geodesic bicombings on subsets of normed vector spaces

abstract:
  In this paper we establish existence and uniqueness results for conical
geodesic bicombings on subsets of normed vector spaces. Concerning existence,
we give a first example of a convex geodesic bicombing that is not consistent.
Furthermore, we show that under a mild geometric assumption on the norm a
conical geodesic bicombing on an open subset of a normed vector space locally
consists of linear geodesics. As an application, we obtain by the use of a
Cartan-Hadamard type result that if a closed convex subset of a Banach space
has non-empty interior, then it admits a unique consistent conical geodesic
bicombing, namely the one given by the linear segments.


title:
Query-Based Entailment and Inseparability for ALC Ontologies (Full
  Version)

abstract:
  We investigate the problem whether two ALC knowledge bases are
indistinguishable by queries over a given vocabulary. We give model-theoretic
criteria in terms of (partial) homomorphisms and products and prove that this
problem is undecidable for conjunctive queries (CQs) but 2EXPTIME-complete for
UCQs (unions of CQs). The same results hold if CQs are replaced by rooted CQs.
We also consider the problem whether two ALC TBoxes give the same answers to
any query in a given vocabulary over all ABoxes, and show that for CQs this
problem is undecidable, too, but becomes decidable and 2EXPTIME-complete in
Horn-ALC, and even EXPTIME-complete in Horn-ALC when restricted to (unions of)
rooted CQs.


title: Remarks on curvature in the transportation metric

abstract:
  According to a classical result of E.~Calabi any hyperbolic affine
hypersphere endowed with its natural Hessian metric has a non-positive Ricci
tensor. The affine hyperspheres can be described as the level sets of solutions
to the "hyperbolic" toric K\"ahler-Einstein equation $e^{\Phi} = \det D^2 \Phi$
on proper convex cones. We prove a generalization of this theorem by showing
that for every
  $\Phi$ solving this equation on a proper convex domain $\Omega$ the
corresponding metric measure space $(D^2 \Phi, e^{\Phi}dx)$ has a non-positive
Bakry-{\'E}mery tensor. Modifying the Calabi computations we obtain this result
by applying the tensorial maximum principle to the weighted Laplacian of the
Bakry-{\'E}mery tensor. Our computations are carried out in a generalized
framework adapted to the optimal transportation problem for arbitrary target
and source measures. For the optimal transportation of the log-concave
probability measures we prove a third-order uniform dimension-free apriori
estimate in the spirit of the second-order Caffarelli contraction theorem,
which has numerous applications in probability theory.


title: Analysis of Interference Correlation in Non-Poisson Networks

abstract:
  The correlation of interference has been well quantified in Poisson networks
where the interferers are independent of each other. However, there exists
dependence among the base stations (BSs) in wireless networks. In view of this,
we quantify the interference correlation in non-Poisson networks where the
interferers are distributed as a Matern cluster process (MCP) and a
second-order cluster process (SOCP). Interestingly, it is found that the
correlation coefficient of interference for the Matern cluster networks,
$\zeta_{MCP}$, is equal to that for second-order cluster networks,
$\zeta_{SOCP}$. Furthermore, they are greater than their counterpart for the
Poisson networks. This shows that clustering in interferers enhances the
interference correlation. In addition, we show that the correlation
coefficients $\zeta_{MCP}$ and $\zeta_{SOCP}$ increase as the average number of
points in each cluster, $c$, grows, but decrease with the increase in the
cluster radius, $R$. More importantly, we point that the effects of clustering
on interference correlation can be neglected as
$\frac{c}{\pi^{2}R^{2}}\rightarrow0$. Finally, the analytical results are
validated by simulations.


title: Predicting Privacy Attitudes Using Phone Metadata

abstract:
  With the increasing usage of smartphones, there is a corresponding increase
in the phone metadata generated by individuals using these devices. Managing
the privacy of personal information on these devices can be a complex task.
Recent research has suggested the use of social and behavioral data for
automatically recommending privacy settings. This paper is the first effort to
connect users' phone use metadata with their privacy attitudes. Based on a
10-week long field study involving phone metadata collection via an app, and a
survey on privacy attitudes, we report that an analysis of cell phone metadata
may reveal vital clues to a person's privacy attitudes. Specifically, a
predictive model based on phone usage metadata significantly outperforms a
comparable personality features-based model in predicting individual privacy
attitudes. The results motivate a newer direction of automatically inferring a
user's privacy attitudes by looking at their phone usage characteristics.


title:
Asymmetry-induced resistive switching in Ag-Ag$_{2}$S-Ag memristors
  enabling a simplified atomic-scale memory design

abstract:
  Prevailing models of resistive switching arising from electrochemical
formation of conducting filaments across solid state ionic conductors commonly
attribute the observed polarity of the voltage-biased switching to the sequence
of the active and inert electrodes confining the resistive switching memory
cell. Here we demonstrate equivalent, stable switching behavior in metallic
Ag-Ag$_{2}$S-Ag nanojunctions at room temperature. Our experimental results and
numerical simulations reveal that the polarity of the switchings is solely
determined by the geometrical asymmetry of the electrode surfaces. By the
lithographical design of a proof of principle device we demonstrate the merits
of simplified fabrication of atomic-scale, robust planar Ag$_{2}$S memory
cells.


title:
A Deterministic Annealing Approach to the Multiple Traveling Salesmen
  and Related Problems

abstract:
  This paper presents a novel and efficient heuristic framework for
approximating the solutions to the multiple traveling salesmen problem (m-TSP)
and other variants on the TSP. The approach adopted in this paper is an
extension of the Maximum-Entropy-Principle (MEP) and the Deterministic
Annealing (DA) algorithm. The framework is presented as a general tool that can
be suitably adapted to a number of variants on the basic TSP. Additionally,
unlike most other heuristics for the TSP, the framework presented in this paper
is independent of the edges defined between any two pairs of nodes. This makes
the algorithm particularly suited for variants such as the close-enough
traveling salesman problem (CETSP) which are challenging due to added
computational complexity. The examples presented in this paper illustrate the
effectiveness of this new framework for use in TSP and many variants thereof.


title: Asymptotic structure of electrodynamics revisited

abstract:
  We point out that recently published analyses of null and timelike infinity
and long-range structures in electrodynamics to large extent rediscover results
present in literature. At the same time, some of the conclusions these recent
works put forward may prove controversial. In view of these facts we find it
desirable to revisit the analysis taken up more than two decades ago, starting
from earlier works on null infinity by other authors.


title:
In situ characterization of few-cycle laser pulses in transient
  absorption spectroscopy

abstract:
  Attosecond transient absorption spectroscopy has thus far been lacking the
capability to simultaneously characterize the intense laser pulses at work
within a time-resolved quantum-dynamics experiment. However, precise knowledge
of these pulses is key to extracting quantitative information in strong-field
highly nonlinear light-matter interactions. Here, we introduce and
experimentally demonstrate an ultrafast metrology tool based on the
time-delay-dependent phase shift imprinted on a strong-field driven resonance.
Since we analyze the signature of the laser pulse interacting with the
absorbing spectroscopy target, the laser pulse duration and intensity are
determined in situ. As we also show, this approach allows for the
quantification of time-dependent bound-state dynamics in one and the same
experiment. In the future, such experimental data will facilitate more precise
tests of strong-field dynamics theories.


title:
A stochastic coordinate descent primal-dual algorithm with dynamic
  stepsize for large-scale composite optimization

abstract:
  In this paper we consider the problem of finding the minimizations of the sum
of two convex functions and the composition of another convex function with a
continuous linear operator. With the idea of coordinate descent, we design a
stochastic coordinate descent primal-dual splitting algorithm with dynamic
stepsize. Based on randomized Modified Krasnosel'skii-Mann iterations and the
firmly nonexpansive properties of the proximity operator, we achieve the
convergence of the proposed algorithms. Moreover, we give two applications of
our method.


title: Distribution-Free Predictive Inference For Regression

abstract:
  We develop a general framework for distribution-free predictive inference in
regression, using conformal inference. The proposed methodology allows for the
construction of a prediction band for the response variable using any estimator
of the regression function. The resulting prediction band preserves the
consistency properties of the original estimator under standard assumptions,
while guaranteeing finite-sample marginal coverage even when these assumptions
do not hold. We analyze and compare, both empirically and theoretically, the
two major variants of our conformal framework: full conformal inference and
split conformal inference, along with a related jackknife method. These methods
offer different tradeoffs between statistical accuracy (length of resulting
prediction intervals) and computational efficiency. As extensions, we develop a
method for constructing valid in-sample prediction intervals called {\it
rank-one-out} conformal inference, which has essentially the same computational
efficiency as split conformal inference. We also describe an extension of our
procedures for producing prediction bands with locally varying length, in order
to adapt to heteroskedascity in the data. Finally, we propose a model-free
notion of variable importance, called {\it leave-one-covariate-out} or LOCO
inference. Accompanying this paper is an R package {\tt conformalInference}
that implements all of the proposals we have introduced. In the spirit of
reproducibility, all of our empirical results can also be easily (re)generated
using this package.


title:
Dynamical Degree and Arithmetic Degree of Endomorphisms on Product
  Varieties

abstract:
  For a dominant rational self-map on a smooth projective variety defined over
a number field, Shu Kawaguchi and Joseph H. Silverman conjectured that the
dynamical degree is equal to the arithmetic degree at a rational point whose
forward orbit is well-defined and Zariski dense. We give some examples of
self-maps on product varieties and rational points on them for which the
Kawaguchi-Silverman conjecture holds.


title:
Highly compact neutron stars in scalar-tensor theories of gravity:
  Spontaneous scalarization versus gravitational collapse

abstract:
  Scalar-tensor theories of gravity are extensions of General Relativity (GR)
including an extra, nonminimally coupled scalar degree of freedom. A wide class
of these theories, albeit indistinguishable from GR in the weak field regime,
predicts a radically different phenomenology for neutron stars, due to a
nonperturbative, strong-field effect referred to as spontaneous scalarization.
This effect is known to occur in theories where the effective linear coupling
$\beta_0$ between the scalar and matter fields is sufficiently negative, i.e.
$\beta_0 \lesssim -4.35$, and has been strongly constrained by pulsar timing
observations.
  In the test-field approximation, spontaneous scalarization manifests itself
as a tachyonic-like instability. Recently, it was argued that, in theories
where $\beta_0>0$, a similar instability would be triggered by sufficiently
compact neutron stars obeying realistic equations of state. In this work we
investigate the endstate of this instability for some representative coupling
functions with $\beta_0>0$. This is done both through an energy balance
analysis of the existing equilibrium configurations, and by numerically
determining the nonlinear Cauchy development of unstable initial data. We find
that, contrary to the $\beta_0<0$ case, the final state of the instability is
highly sensitive to the details of the coupling function, varying from
gravitational collapse to spontaneous scalarization. In particular, we show,
for the first time, that spontaneous scalarization can happen in theories with
$\beta_0>0$, which could give rise to novel astrophysical tests of the theory
of gravity.


title:
Completely Controlling the Dimensions of Formal Fiber Rings at Prime
  Ideals of Small Height

abstract:
  Let $T$ be a complete equicharacteristic local (Noetherian) UFD of dimension
$3$ or greater. Assuming that $|T| = |T/m|$, where $m$ is the maximal ideal of
$T$, we construct a local UFD $A$ whose completion is $T$ and whose formal
fibers at height one prime ideals have prescribed dimension between zero and
the dimension of the generic formal fiber. If, in addition, $T$ is regular and
has characteristic zero, we can construct $A$ to be excellent.


title: Traveling Pulses for a Two-Species Chemotaxis Model

abstract:
  Mathematical models have been widely used to describe the collective movement
of bacteria by chemotaxis. In particular, bacterial concentration waves
traveling in a narrow channel have been experimentally observed and can be
precisely described thanks to a mathematical model at the macroscopic scale.
Such model was derived in [1] using a kinetic model based on an accurate
description of the mesoscopic run-and-tumble process. We extend this approach
to study the behavior of the interaction between two populations of E. Coli.
Separately, each population travels with its own speed in the channel. When put
together, a synchronization of the speed of the traveling pulses can be
observed. We show that this synchronization depends on the fraction of the fast
population. Our approach is based on mathematical analysis of a macroscopic
model of partial differential equations. Numerical simulations in comparison
with experimental observations show qualitative agreement.


title: Exploring the many-body localization transition in two dimensions

abstract:
  One fundamental assumption in statistical physics is that generic closed
quantum many-body systems thermalize under their own dynamics. Recently, the
emergence of many-body localized systems has questioned this concept,
challenging our understanding of the connection between statistical physics and
quantum mechanics. Here we report on the observation of a many-body
localization transition between thermal and localized phases for bosons in a
two-dimensional disordered optical lattice. With our single site resolved
measurements we track the relaxation dynamics of an initially prepared
out-of-equilibrium density pattern and find strong evidence for a diverging
length scale when approaching the localization transition. Our experiments mark
the first demonstration and in-depth characterization of many-body localization
in a regime not accessible with state-of-the-art simulations on classical
computers.

categories: cond-mat.quant-gas cond-mat.dis-nn cond-mat.stat-mech cond-mat.str-el


title: Topological quantum fluctuations and travelling wave amplifiers

abstract:
  It is now well-established that photonic systems can exhibit topological
energy bands; similar to their electronic counterparts, this leads to the
formation of chiral edge modes which can be used to transmit light in a manner
that is protected against back-scattering. While it is understood how classical
signals can propagate under these conditions, it is an outstanding important
question how the quantum vacuum fluctuations of the electromagnetic field get
modified in the presence of a topological band structure. We address this
challenge by exploring a setting where a non-zero topological invariant
guarantees the presence of a parametrically-unstable chiral edge mode in a
system with boundaries, even though there are no bulk-mode instabilities. We
show that one can exploit this to realize a topologically protected,
quantum-limited travelling-wave parametric amplifier. The device is naturally
protected both against internal losses and back-scattering; the latter feature
is in stark contrast to standard travelling wave amplifiers. This adds a new
example to the list of potential quantum devices that profit from topological
transport.


title: Job Selection in a Network of Autonomous UAVs for Delivery of Goods

abstract:
  This article analyzes two classes of job selection policies that control how
a network of autonomous aerial vehicles delivers goods from depots to
customers. Customer requests (jobs) occur according to a spatio-temporal
stochastic process not known by the system. If job selection uses a policy in
which the first job (FJ) is served first, the system may collapse to
instability by removing just one vehicle. Policies that serve the nearest job
(NJ) first show such threshold behavior only in some settings and can be
implemented in a distributed manner. The timing of job selection has
significant impact on delivery time and stability for NJ while it has no impact
for FJ. Based on these findings we introduce a methodological approach for
decision-making support to set up and operate such a system, taking into
account the trade-off between monetary cost and service quality. In particular,
we compute a lower bound for the infrastructure expenditure required to achieve
a certain expected delivery time. The approach includes three time horizons:
long-term decisions on the number of depots to deploy in the service area,
mid-term decisions on the number of vehicles to use, and short-term decisions
on the policy to operate the vehicles.


title:
Restricted thermodynamic fluctuations and the Ruppeiner geometry of
  black holes

abstract:
  Thermodynamic fluctuation metrics in Ruppeiner's formalism are worked out for
Kerr-AdS black holes in the extended state space. The implications of
constraints upon the state space geometry and their correspondence with
thermodynamical ensembles are explicitly worked out in the most general
setting. The state space scalar curvature for a given ensemble is found to be
sensitive to the instabilities/phase transitions therein. In particular, it is
found that the appropriate Ruppeiner scalar curvature does encode critical
phenomena in the Kerr-AdS black holes. A detailed study is undertaken of the
curvature contour of the state space of the 4d Kerr-AdS black hole and suitable
inferences are drawn. In particular, thermodynamic geometry suggests an
instability in the Schwarzschild-AdS limit for all the ensembles except the
pressure ensemble which is equivalent to the unextended state space of the
Kerr-AdS black holes. The extrinsic geometry of the ensemble hypersurfaces is
introduced and its relevance to constrained thermodynamic fluctuations
discussed. A new interpretation for the thermodynamic curvature of black hole
systems is suggested.


title: Consistently Estimating Markov Chains with Noisy Aggregate Data

abstract:
  We address the problem of estimating the parameters of a time-homogeneous
Markov chain given only noisy, aggregate data. This arises when a population of
individuals behave independently according to a Markov chain, but individual
sample paths cannot be observed due to limitations of the observation process
or the need to protect privacy. Instead, only population-level counts of the
number of individuals in each state at each time step are available. When these
counts are exact, a conditional least squares (CLS) estimator is known to be
consistent and asymptotically normal. We initiate the study of method of
moments estimators for this problem to handle the more realistic case when
observations are additionally corrupted by noise. We show that CLS can be
interpreted as a simple "plug-in" method of moments estimator. However, when
observations are noisy, it is not consistent because it fails to account for
additional variance introduced by the noise. We develop a new, simpler method
of moments estimator that bypasses this problem and is consistent under noisy
observations.


title: Dark energy as the weight of violating energy conservation

abstract:
  In this letter, we consider the possibility of reconciling metric theories of
gravitation with violation of the conservation of energy-momentum. Under some
circumstances, this can be achieved in the context of unimodular gravity, and
it leads to the emergence of an effective cosmological constant in Einstein's
equation. We specifically investigate two potential sources of energy
non-conservation ---non-unitary modifications of quantum mechanics, and
phenomenological models motivated by quantum gravity theories with spacetime
discreteness at the Planck scale--- and show that such locally negligible
phenomena can nevertheless become relevant at the cosmological scale.

categories: gr-qc astro-ph.CO hep-ph hep-th quant-ph


title: Quantification of tidal parameters from Solar system data

abstract:
  Tidal dissipation is the main driver of orbital evolution of natural
satellites and a key point to understand the exoplanetary system
configurations. Despite its importance, its quantification from observations
still remains difficult for most objects of our own Solar system. In this work,
we overview the method that has been used to determine, directly from
observations, the tidal parameters, with emphasis on the Love number k2 and the
tidal quality factor Q. Up-to-date values of these tidal parameters are
summarized. Last, an assessment on the possible determination of the tidal
ratio k2/Q of Uranus and Neptune is done. This may be particularly relevant for
coming astrometric campaigns and future space missions focused on these
systems.


title: SLING: A Near-Optimal Index Structure for SimRank

abstract:
  SimRank is a similarity measure for graph nodes that has numerous
applications in practice. Scalable SimRank computation has been the subject of
extensive research for more than a decade, and yet, none of the existing
solutions can efficiently derive SimRank scores on large graphs with provable
accuracy guarantees. In particular, the state-of-the-art solution requires up
to a few seconds to compute a SimRank score in million-node graphs, and does
not offer any worst-case assurance in terms of the query error.
  This paper presents SLING, an efficient index structure for SimRank
computation. SLING guarantees that each SimRank score returned has at most
$\varepsilon$ additive error, and it answers any single-pair and single-source
SimRank queries in $O(1/\varepsilon)$ and $O(n/\varepsilon)$ time,
respectively. These time complexities are near-optimal, and are significantly
better than the asymptotic bounds of the most recent approach. Furthermore,
SLING requires only $O(n/\varepsilon)$ space (which is also near-optimal in an
asymptotic sense) and $O(m/\varepsilon + n\log \frac{n}{\delta}/\varepsilon^2)$
pre-computation time, where $\delta$ is the failure probability of the
preprocessing algorithm. We experimentally evaluate SLING with a variety of
real-world graphs with up to several millions of nodes. Our results demonstrate
that SLING is up to $10000$ times (resp. $110$ times) faster than competing
methods for single-pair (resp. single-source) SimRank queries, at the cost of
higher space overheads.


title: White-light continuum emission from a solar flare and plage

abstract:
  Observations of flare emissions in the optical continuum are very rare.
Therefore, the analysis of such observations is useful and may contribute to
our understanding of the flaring chromosphere and photosphere. We study the
white light continuum emission observed during the X6.9 flare which occurred on
August 09, 2011. This emission comes not only from the flare ribbons but also
from the nearby plage area. The main aim of this work is to disentangle the
flare and plage (facula) emission. We analyzed the spatial, spectral and
temporal evolution of the flare and plage properties by analyzing
multi-wavelength observations. We study the morphological correlation of the
whitelight continuum emission observed with different instruments. We found
that some active region areas which produce the continuum emission correspond
rather to plages than to the flare kernels. We showed that in some cases the
continuum emission from the WL flare kernels is very similar to the continuum
emission of faculae.


title:
Geometric properties of surfaces with the same mean curvature in R^3 and
  L^3

abstract:
  Spacelike surfaces in the Lorentz-Minkowski space L^3 can be endowed with two
different Riemannian metrics, the metric inherited from L^3 and the one induced
by the Euclidean metric of R^3. It is well known that the only surfaces with
zero mean curvature with respect to both metrics are open pieces of the
helicoid and of spacelike planes. We consider the general case of spacelike
surfaces with the same mean curvature with respect to both metrics. One of our
main results states that those surfaces have non-positive Gaussian curvature in
R^3. As an application of this result, jointly with a general argument on the
existence of elliptic points, we present several geometric consequences for the
surfaces we are considering. Finally, as any spacelike surface in L^3 is
locally a graph over a domain of the plane x_3=0, our surfaces are locally
determined by the solutions to the H_R=H_L surface equation. Some uniqueness
results for the Dirichlet problem associated to this equation are given.


title: On the cohomology classes of planar polygon spaces

abstract:
  We obtain an explicit formula for the Poincare duality isomorphism
H^{n-3}(Mbar(ell)) to Z/2 for the space of isometry classes of n-gons with
specified side lengths, if ell is monogenic in the sense of Hausmann-Rodriguez.
This has potential application to topological complexity.


title:
Sobolev and Lipschitz regularity for local minimizers of widely
  degenerate anisotropic functionals

abstract:
  We prove higher differentiability of bounded local minimizers to some widely
degenerate functionals, verifying superquadratic anisotropic growth conditions.
In the two dimensional case, we prove that local minimizers to a model
functional are locally Lipschitz continuous functions, without any restriction
on the anisotropy.


title: Valley Trion Dynamics in Monolayer MoSe$_2$

abstract:
  Charged excitons called trions play an important role in the fundamental
valley dynamics in the newly emerging 2D semiconductor materials. We used
ultrafast pump- probe spectroscopy to study the valley trion dynamics in a
MoSe$_2$ monolayer grown by using chemical vapor deposition. The dynamics
display an ultrafast trion formation followed by a non-exponential decay. The
measurements at different pump fluences show that the trion decay dynamics
become slower as the excitation density increases. The observed trion dynamics
and the associated density dependence are a result of the trapping by two
defect states as being the dominating decay mechanism. The simulation based on
a set of rate equations reproduces the experimental data for different pump
fluences. Our results reveal the important trion dynamics and identify the
trapping by defect states as the primary trion decay mechanism in monolayer
MoSe$_2$ under the excitation densities used in our experiment.


title:
1-bit Matrix Completion: PAC-Bayesian Analysis of a Variational
  Approximation

abstract:
  Due to challenging applications such as collaborative filtering, the matrix
completion problem has been widely studied in the past few years. Different
approaches rely on different structure assumptions on the matrix in hand. Here,
we focus on the completion of a (possibly) low-rank matrix with binary entries,
the so-called 1-bit matrix completion problem. Our approach relies on tools
from machine learning theory: empirical risk minimization and its convex
relaxations. We propose an algorithm to compute a variational approximation of
the pseudo-posterior. Thanks to the convex relaxation, the corresponding
minimization problem is bi-convex, and thus the method behaves well in
practice. We also study the performance of this variational approximation
through PAC-Bayesian learning bounds. On the contrary to previous works that
focused on upper bounds on the estimation error of M with various matrix norms,
we are able to derive from this analysis a PAC bound on the prediction error of
our algorithm.
  We focus essentially on convex relaxation through the hinge loss, for which
we present the complete analysis, a complete simulation study and a test on the
MovieLens data set. However, we also discuss a variational approximation to
deal with the logistic loss.


title: Topological Surgery, Dynamics and Applications To Natural Processes

abstract:
  In this paper we observe that 2-dimensional 0-surgery occurs in natural
processes, such as tornado formation and other phenomena reminiscent of hole
drilling. Inspired by such phenomena, we introduce new theoretical concepts
which enhance the formal definition of 2-dimensional 0-surgery with the
observed dynamics. To do this, we first present a schematic model which extends
the formal definition to a continuous process caused by local forces. Next, for
modeling phenomena which do not happen on surfaces but are three-dimensional,
we fill the interior space by defining the notion of solid 2-dimensional
0-surgery. Finally, we connect these new theoretical concepts with a dynamical
system and present it as a model for both 2-dimensional 0-surgery and natural
phenomena exhibiting it. We hope that through this study, topology and dynamics
of many natural phenomena will be better understood.


title: Loss of solution in the symmetry improved Phi-derivable expansion scheme

abstract:
  We consider the two-loop Phi-derivable approximation for the O(2)-symmetric
scalar model, augmented by the symmetry improvement introduced in [A. Pilaftsis
and D. Teresi, Nucl. Phys. B874, 594 (2013)], which enforces Goldstone's
theorem in the broken phase. Although the corresponding equations admit a
solution in the presence of a large enough infrared (IR) regulating scale, we
argue that, for smooth ultraviolet (UV) regulators, the solution is lost when
the IR scale becomes small enough. Infrared regular solutions exist for certain
non-analytic UV regulators, but we argue that these solutions are artifacts
which should disappear when the sensitivity to the UV regulator is removed by a
renormalization procedure. The loss of solution is observed both at zero and at
finite temperature, although it is simpler to identify in the latter case. We
also comment on possible ways to cure this problem.


title:
Wonderful compactifications of the moduli space of points in affine and
  projective space

abstract:
  We introduce and study smooth compactifications of the moduli space of n
labeled points with weights in projective space, which have normal crossings
boundary and are defined as GIT quotients of the weighted Fulton-MacPherson
compactification. We show that the GIT quotient of a wonderful compactification
is also a wonderful compactification under certain hypotheses. We also study a
weighted version of the configuration spaces parametrizing n points in affine
space up to translation and homothety. In dimension one, the above
compactifications are isomorphic to Hassett's moduli space of rational weighted
stable curves.


title:
WASP-South transiting exoplanets: WASP-130b, WASP-131b, WASP-132b,
  WASP-139b, WASP-140b, WASP-141b & WASP-142b

abstract:
  We describe seven exoplanets transiting stars of brightness V = 10.1 to 12.4.
WASP-130b is a "warm Jupiter" having an orbital period of 11.6 d around a
metal-rich G6 star. Its mass and radius (1.23 +/- 0.04 Mjup; 0.89 +/- 0.03
Rjup) support the trend that warm Jupiters have smaller radii than hot
Jupiters. WASP-131b is a bloated Saturn-mass planet (0.27 Mjup; 1.22 Rjup). Its
large scale height and bright (V = 10.1) host star make it a good target for
atmospheric characterisation. WASP-132b (0.41 Mjup; 0.87 Rjup) is among the
least irradiated and coolest of WASP planets, having a 7.1-d orbit around a K4
star. WASP-139b is a "super-Neptune" akin to HATS-7b and HATS-8b, being the
lowest-mass planet yet found by WASP (0.12 Mjup; 0.80 Rjup). The metal-rich K0
host star appears to be anomalously dense, akin to HAT-P-11. WASP-140b is a
2.4-Mjup planet in an eccentric (e = 0.047 +/- 0.004) 2.2-d orbit. The planet's
radius is large (1.4 Rjup), but uncertain owing to the grazing transit (b =
0.93). The 10.4-day rotation period of the K0 host star suggests a young age,
and the timescale for tidal circularisation is likely to be the lowest of all
known eccentric hot Jupiters. WASP-141b (2.7 Mjup, 1.2 Rjup, P = 3.3 d) and
WASP-142b (0.84 Mjup, 1.53 Rjup, P = 2.1 d) are typical hot Jupiters orbiting
metal-rich F stars. We show that the period distribution within the hot-Jupiter
bulge does not depend on the metallicity of the host star.


title:
Discovery of Broad Soft X-ray Absorption Lines from the Quasar Wind in
  PDS 456

abstract:
  High resolution soft X-ray spectroscopy of the prototype accretion disk wind
quasar, PDS 456, is presented. Here, the XMM-Newton RGS spectra are analyzed
from the large 2013-2014 XMM-Newton campaign, consisting of 5 observations of
approximately 100 ks in length. During the last observation (hereafter OBS. E),
the quasar is at a minimum flux level and broad absorption line profiles are
revealed in the soft X-ray band, with typical velocity widths of $\sigma_{\rm
v}\sim 10,000$ km s$^{-1}$. During a period of higher flux in the 3rd and 4th
observations (OBS. C and D, respectively), a very broad absorption trough is
also present above 1 keV. From fitting the absorption lines with models of
photoionized absorption spectra, the inferred outflow velocities lie in the
range $\sim 0.1-0.2c$. The absorption lines likely originate from He and H-like
neon and L-shell iron at these energies. Comparison with earlier archival data
of PDS 456 also reveals similar absorption structure near 1 keV in a 40 ks
observation in 2001, and generally the absorption lines appear most apparent
when the spectrum is more absorbed overall. The presence of the soft X-ray
broad absorption lines is also independently confirmed from an analysis of the
XMM-Newton EPIC spectra below 2 keV. We suggest that the soft X-ray absorption
profiles could be associated with a lower ionization and possibly clumpy phase
of the accretion disk wind, where the latter is known to be present in this
quasar from its well studied iron K absorption profile and where the wind
velocity reaches a typical value of 0.3$c$.


title: Topological Self-Stabilization with Name-Passing Process Calculi

abstract:
  Topological self-stabilization describes the ability of a distributed system
to let the nodes themselves establish a meaningful overlay network. Independent
from the initial network topology, the system converges to the desired topology
via forwarding, inserting, and deleting links to neighboring nodes.
Name-passing process calculi, like the pi-calculus, are a well-known and widely
used method to model concurrent and distributed algorithms. The pi-calculus is
designed to naturally express processes with a changing link infrastructure, as
the communication between processes may carry information that can be used for
a change in the linkage between the processes. We redesign a simple local
linearization algorithm with asynchronous message-passing that was originally
designed for a shared memory model. We use an extended localized pi-calculus, a
variant of the pi-calculus, to model the algorithm. Subsequently, we formally
prove the self-stabilizing properties closure, weak convergence for every
arbitrary initial configuration, and strong convergence for two special cases.
In our proofs we utilize rather an assertional reasoning than an action-based
style. Furthermore, we describe the challenges in proving (strong) convergence
in the general case. Additionally, we give strong arguments for strong
convergence, supported by further proven lemmata, and discuss different
approaches for a formal proof.


title:
Estimating parameters of nonlinear systems using the elitist particle
  filter based on evolutionary strategies

abstract:
  In this article, we present the elitist particle filter based on evolutionary
strategies (EPFES) as an efficient approach for nonlinear system
identification. The EPFES is derived from the frequently-employed state-space
model, where the relevant information of the nonlinear system is captured by an
unknown state vector. Similar to classical particle filtering, the EPFES
consists of a set of particles and respective weights which represent different
realizations of the latent state vector and their likelihood of being the
solution of the optimization problem. As main innovation, the EPFES includes an
evolutionary elitist-particle selection which combines long-term information
with instantaneous sampling from an approximated continuous posterior
distribution. In this article, we propose two advancements of the
previously-published elitist-particle selection process. Further, the EPFES is
shown to be a generalization of the widely-used Gaussian particle filter and
thus evaluated with respect to the latter for two completely different
scenarios: First, we consider the so-called univariate nonstationary growth
model with time-variant latent state variable, where the evolutionary selection
of elitist particles is evaluated for non-recursively calculated particle
weights. Second, the problem of nonlinear acoustic echo cancellation is
addressed in a simulated scenario with speech as input signal: By using
long-term fitness measures, we highlight the efficacy of the well-generalizing
EPFES in estimating the nonlinear system even for large search spaces. Finally,
we illustrate similarities between the EPFES and evolutionary algorithms to
outline future improvements by fusing the achievements of both fields of
research.


title: NEWS: Nuclear Emulsions for WIMP Search

abstract:
  Nowadays there is compelling evidence for the existence of dark matter in the
Universe. A general consensus has been expressed on the need for a directional
sensitive detector to confirm, with a complementary approach, the candidates
found in conventional searches and to finally extend their sensitivity beyond
the limit of neutrino-induced background. We propose here the use of a detector
based on nuclear emulsions to measure the direction of WIMP-induced nuclear
recoils. The production of nuclear emulsion films with nanometric grains is
established. Several measurement campaigns have demonstrated the capability of
detecting sub-micrometric tracks left by low energy ions in such emulsion
films. Innovative analysis technologies with fully automated optical
microscopes have made it possible to achieve the track reconstruction for path
lengths down to one hundred nanometers and there are good prospects to further
exceed this limit. The detector concept we propose foresees the use of a bulk
of nuclear emulsion films surrounded by a shield from environmental
radioactivity, to be placed on an equatorial telescope in order to cancel out
the effect of the Earth rotation, thus keeping the detector at a fixed
orientation toward the expected direction of galactic WIMPs. We report the
schedule and cost estimate for a one-kilogram mass pilot experiment, aiming at
delivering the first results on the time scale of six years.


title: Stable artificial solid electrolyte interfaces for lithium batteries

abstract:
  A rechargeable lithium metal battery (LMB), which uses metallic lithium at
the anode, is among the most promising technologies for next generation
electrochemical energy storage devices due to its high energy density,
particularly when Li is paired with energetic conversion cathodes such as
sulfur, oxygen/air, and carbon dioxide. Practical LMBs in any of these designs
remain elusive due to multiple stubborn problems, including parasitic reactions
of Li metal with liquid electrolytes, unstable/dendritic electrodeposition at
the anode during cell recharge, and chemical reaction of dissolved cathode
conversion products with the Li anode. The solid electrolyte interface (SEI)
formed between lithium metal and liquid electrolytes plays a critical role in
all of these processes. We report on the chemistry and interfacial properties
of artificial SEI films created by in-situ reaction of a strong Lewis Acid AlI3
additive, Li metal, and aprotic liquid electrolytes. We find that these SEI
films impart exceptional interfacial stability to a Li metal anode. We further
show that the improvements come from at least three processes: (i) in-situ
formation of Li-Al alloy, (ii) formation of a LiI salt layer on Li, and (iii)
creation of a stable polymer thin film on the lithium metal anode.