title: Canonical Heights on Genus Two Jacobians

abstract:
  Let $K$ be a number field and let $C/K$ be a curve of genus 2 with Jacobian
variety $J$. In this paper, we study the canonical height $\hat{h} \colon J(K)
\to \mathbb R$. More specifically, we consider the following two problems,
which are important in applications:
  (1) for a given $P \in J(K)$, compute $\hat{h}(P)$ efficiently;
  (2) for a given bound $B > 0$, find all $P \in J(K)$ with $\hat{h}(P) \le B$.
  We develop an algorithm running in polynomial time (and fast in practice) to
deal with the first problem. Regarding the second problem, we show how one can
tweak the naive height $h$ that is usually used to obtain significantly
improved bounds for the difference $h - \hat{h}$, which allows a much faster
enumeration of the desired set of points.
  Our approach is to use the standard decomposition of $h(P) - \hat{h}(P)$ as a
sum of local `height correction functions'. We study these functions carefully,
which leads to efficient ways of computing them and to essentially optimal
bounds. To get our polynomial-time algorithm, we have to avoid the
factorization step needed to find the finite set of places where the correction
might be nonzero. The main innovation at this point is to replace factorization
into primes by factorization into coprimes.
  Most of our results are valid for more general fields with a set of absolute
values satisfying the product formula.
  An analogous approach to (1) above for elliptic curves was used in our recent
paper arXiv:1509.08748.


title: Explosion of white dwarfs harboring hybrid CONe cores

abstract:
  Recently, it has been found that off-centre carbon burning in a subset of
intermediate-mass stars does not propagate all the way to the center, resulting
in a class of hybrid CONe cores. Here, we consider the possibility that stars
hosting these hybrid CONe cores might belong to a close binary system and,
eventually, become white dwarfs accreting from a non-degenerate companion at
rates leading to a supernova explosion. We have computed the hydrodynamical
phase of the explosion of Chandrasekhar-mass white dwarfs harboring hybrid
cores, assuming that the explosion starts at the center, either as a detonation
(as may be expected in some degenerate merging scenarios) or as a deflagration
(that afterwards transitions into a delayed detonation). We assume these hybrid
cores are made of a central CO volume, of mass M(CO), surrounded by an ONe
shell. We show that, in case of a pure detonation, a medium-sized CO-rich
region, M(CO)<0.4 Msun, results in the ejection of a small fraction of the
mantle while leaving a massive bound remnant. Part of this remnant is made of
the products of the detonation, Fe-group nuclei, but they are buried in its
inner regions, unless convection is activated during the ensuing cooling and
shrinking phase of the remnant. In contrast, and somehow paradoxically, delayed
detonations do not leave remnants but for the minimum M(CO) we have explored,
M(CO)=0.2 Msun, and even in this case the remnant is as small as 0.13 Msun. The
ejecta produced by these delayed detonations are characterized by slightly
smaller masses of 56Ni and substantially smaller kinetic energies than obtained
for a delayed detonation of a 'normal' CO white dwarf. The optical emission
expected from these explosions would hardly match the observational properties
of typical Type Ia supernovae, although they make interesting candidates for
the subluminous class of SN2002cx-like or SNIax.


title: Structure of the number projected BCS wave function

abstract:
  We study the structure of the number projected BCS (PBCS) wave function in
the particle-hole basis, displaying its similarities with coupled clusters
theory (CCT). The analysis of PBCS together with several modifications
suggested by the CCT wave function is carried out for the exactly solvable
Richardson model involving a pure pairing hamiltonian acting in a space of
equally-spaced doubly-degenerate levels. We point out the limitations of PBCS
to describe the non-superconducting regime and suggest possible avenues for
improvement.


title: Symmetrization in Geometry

abstract:
  The concept of an $i$-symmetrization is introduced, which provides a
convenient framework for most of the familiar symmetrization processes on
convex sets. Various properties of $i$-symmetrizations are introduced and the
relations between them investigated. New expressions are provided for the
Steiner and Minkowski symmetrals of a compact convex set which exhibit a dual
relationship between them. Characterizations of Steiner, Minkowski and central
symmetrization, in terms of natural properties that they enjoy, are given and
examples are provided to show that none of the assumptions made can be dropped
or significantly weakened. Other familiar symmetrizations, such as Schwarz
symmetrization, are discussed and several new ones introduced.


title: A Novel Interleaving Scheme for Polar Codes

abstract:
  It's known that the bit errors of polar codes with successive cancellation
(SC) decoding are coupled. We call the coupled information bits the correlated
bits. In this paper, concatenation schemes are studied for polar codes (as
inner codes) and LDPC codes (as outer codes). In a conventional concatenation
scheme, to achieve a better BER performance, one can divide all $N_l$ bits in a
LDPC block into $N_l$ polar blocks to completely de-correlate the possible
coupled errors. In this paper, we propose a novel interleaving scheme between a
LDPC code and a polar code which breaks the correlation of the errors among the
correlated bits. This interleaving scheme still keeps the simple SC decoding of
polar codes while achieves a comparable BER performance at a much smaller delay
compared with a $N_l$-block delay scheme.


title: A spatial model for selection and cooperation

abstract:
  We study the evolution of cooperation in an interacting particle system with
two types. The model we investigate is an extension of a two-type biased voter
model. One type (called defector) has a (positive) bias $\alpha$ with respect
to the other type (called cooperator). However, a cooperator helps a neighbor
(either defector or cooperator) to reproduce at rate $\gamma$. We prove that
the one-dimensional nearest-neighbor interacting dynamical system exhibits a
phase transition at $\alpha=\gamma$. For $\alpha>\gamma$ cooperators always die
out, but if $\gamma>\alpha$, cooperation is the winning strategy.


title:
Are you Charlie or Ahmed? Cultural pluralism in Charlie Hebdo response
  on Twitter

abstract:
  We study the response to the Charlie Hebdo shootings of January 7, 2015 on
Twitter across the globe. We ask whether the stances on the issue of freedom of
speech can be modeled using established sociological theories, including
Huntington's culturalist Clash of Civilizations, and those taking into
consideration social context, including Density and Interdependence theories.
We find support for Huntington's culturalist explanation, in that the
established traditions and norms of one's "civilization" predetermine some of
one's opinion. However, at an individual level, we also find social context to
play a significant role, with non-Arabs living in Arab countries using
#JeSuisAhmed ("I am Ahmed") five times more often when they are embedded in a
mixed Arab/non-Arab (mention) network. Among Arabs living in the West, we find
a great variety of responses, not altogether associated with the size of their
expatriate community, suggesting other variables to be at play.


title:
Embedding central extensions of simple linear groups into wreath
  products

abstract:
  We find a criterion for the embedding of a nonsplit central extension of
$PSL_n(q)$ with kernel of prime order into the permutation wreath product that
corresponds to the action on the projective space.


title:
Superimposed Pilots are Superior for Mitigating Pilot Contamination in
  Massive MIMO

abstract:
  In this paper, superimposed pilots are introduced as an alternative to
time-multiplexed pilot and data symbols for mitigating pilot contamination in
massive multiple-input multiple-output (MIMO) systems. We propose a
non-iterative scheme for uplink channel estimation based on superimposed pilots
and derive an expression for the uplink signal-to-interference-plus-noise ratio
(SINR) at the output of a matched filter employing this channel estimate. Based
on this expression, we observe that power control is essential when
superimposed pilots are employed. Moreover, the quality of the channel estimate
can be improved by reducing the interference that results from transmitting
data alongside the pilots, and an intuitive iterative data-aided scheme that
reduces this component of interference is also proposed. Approximate
expressions for the uplink SINR are provided for the iterative data-aided
method as well. In addition, we show that a hybrid system with users utilizing
both time-multiplexed and superimposed pilots is superior to an optimally
designed system that employs only time-multiplexed pilots, even when the
non-iterative channel estimate is used to build the detector and precoder. We
also describe a simple approach to implement this hybrid system by minimizing
the overall inter and intra-cell interference. Numerical simulations
demonstrating the performance of the proposed channel estimation schemes and
the superiority of the hybrid system are also provided.


title:
Automatic Verification of Iterated Separating Conjunctions using
  Symbolic Execution

abstract:
  In permission logics such as separation logic, the iterated separating
conjunction is a quantifier denoting access permission to an unbounded set of
heap locations. In contrast to recursive predicates, iterated separating
conjunctions do not prescribe a structure on the locations they range over, and
so do not restrict how to traverse and modify these locations. This flexibility
is important for the verification of random-access data structures such as
arrays and data structures that can be traversed in multiple ways such as
graphs. Despite its usefulness, no automatic program verifier natively supports
iterated separating conjunctions; they are especially difficult to incorporate
into symbolic execution engines, the prevalent technique for building verifiers
for these logics.
  In this paper, we present the first symbolic execution technique to support
general iterated separating conjunctions. We propose a novel representation of
symbolic heaps and flexible support for logical specifications that quantify
over heap locations. Our technique exhibits predictable and fast performance
despite employing quantifiers at the SMT level, by carefully controlling
quantifier instantiations. It is compatible with other features of permission
logics such as fractional permissions, recursive predicates, and abstraction
functions. Our technique is implemented as an extension of the Viper
verification infrastructure.


title:
Limits of sequences of continuous functions depending on finitely many
  coordinates

abstract:
  We answer two questions from {\it V.Bykov, On Baire class one functions on a
product space, Topol. Appl. {199} (2016) 55--62,} and prove that every Baire
one function on a subspace of a countable perfectly normal product is the
pointwise limit of a sequence of continuous functions, each depending on
finitely many coordinates. It is proved also that a lower semicontinuous
function on a subspace of a countable perfectly normal product is the pointwise
limit of an increasing sequence of continuous functions, each depending on
finitely many coordinates, if and only if the function has a minorant which
depends on finitely many coordinates.


title: Perturbative Expansion for the Maximum of Fractional Brownian Motion

abstract:
  Brownian motion is the only random process which is Gaussian, stationary and
Markovian. Dropping the Markovian property, i.e. allowing for memory, one
obtains a class of processes called fractional Brownian motion, indexed by the
Hurst exponent $H$. For $H=1/2$, Brownian motion is recovered. We develop a
perturbative approach to treat the non-locality in time in an expansion in
$\varepsilon = H-1/2$. This allows us to derive analytic results beyond scaling
exponents for various observables related to extreme value statistics: The
maximum $m$ of the process and the time $t_{\text{max}}$ at which this maximum
is reached, as well as their joint distribution. We test our analytical
predictions with extensive numerical simulations for different values of $H$.
They show excellent agreement, even for $H$ far from $1/2$.


title:
Physics-Based Damage-Aware Manipulation Strategy Planning Using Scene
  Dynamics Anticipation

abstract:
  We present a damage-aware planning approach which determines the best
sequence to manipulate a number of objects in a scene. This works on
task-planning level, abstracts from motion planning and anticipates the
dynamics of the scene using a physics simulation. Instead of avoiding
interaction with the environment, we take unintended motion of other objects
into account and plan manipulation sequences which minimize the potential
damage. Our method can also be used as a validation measure to judge planned
motions for their feasibility in terms of damage avoidance. We evaluate our
approach on one industrial scenario (autonomous container unloading) and one
retail scenario (shelf replenishment).


title: Growth of eccentric modes in disc-planet interactions

abstract:
  We formulate a set of linear equations that describe the behaviour of small
eccentricities in a protoplanetary system consisting of a gaseous disc and a
planet. Eccentricity propagates through the disc by means of pressure and
self-gravity, and is exchanged with the planet via secular interactions.
Excitation and damping of eccentricity can occur through Lindblad and
corotation resonances, as well as viscosity. We compute normal modes of the
coupled disc-planet system in the case of short-period giant planets orbiting
inside an inner cavity, possibly carved by the stellar magnetosphere.
Three-dimensional effects allow for a mode to be trapped in the inner parts of
the disc. This mode can easily grow within the disc's lifetime. An eccentric
mode dominated by the planet can also grow, although less rapidly. We compute
the structure and growth rates of these modes and their dependence on the
assumed properties of the disc.


title: de Sitter vacua from an anomalous gauge symmetry

abstract:
  We find a new class of metastable de Sitter solutions in compactifications of
six-dimensional supergravity motivated by type IIB or heterotic string vacua.
Two Fayet-Iliopoulos terms of a local U(1) symmetry are generated by magnetic
flux and by the Green-Schwarz term canceling the gauge anomalies, respectively.
The interplay between the induced D-term, the moduli dependence of the
effective gauge coupling, and a nonperturbative superpotential stabilizes the
moduli and determines the size of the extra dimensions.


title:
Magnetic variability in the young solar analog KIC 10644253:
  Observations from the Kepler satellite and the HERMES spectrograph

abstract:
  The continuous photometric observations collected by the Kepler satellite
over 4 years provide a whelm of data with an unequalled quantity and quality
for the study of stellar evolution of more than 200000 stars. Moreover, the
length of the dataset provide a unique source of information to detect magnetic
activity and associated temporal variability in the acoustic oscillations. In
this regards, the Kepler mission was awaited with great expectation. The search
for the signature of magnetic activity variability in solar-like pulsations
still remained unfruitful more than 2 years after the end of the nominal
mission. Here, however, we report the discovery of temporal variability in the
low-degree acoustic frequencies of the young (1 Gyr-old) solar analog KIC
10644253 with a modulation of about 1.5 years with significant temporal
variations along the duration of the Kepler observations. The variations are in
agreement with the derived photometric activity. The frequency shifts extracted
for KIC 10644253 are shown to result from the same physical mechanisms involved
in the inner sub-surface layers as in the Sun. In parallel, a detailed
spectroscopic analysis of KIC 10644253 is performed based on complementary
ground-based, high-resolution observations collected by the HERMES instrument
mounted on the MERCATOR telescope. Its lithium abundance and chromospheric
activity S-index confirm that KIC 10644253 is a young and more active star than
the Sun.


title:
Model-Based Testing, Using Belief-Desire-Intentions Agents, of Control
  Code for Robots in Collaborative Human-Robot Interactions

abstract:
  The software of robotic assistants needs to be verified, to ensure its safety
and functional correctness. Testing in simulation allows a high degree of
realism in the verification. However, generating tests that cover both
interesting foreseen and unforeseen scenarios in human-robot interaction (HRI)
tasks, while executing most of the code, remains a challenge. We propose the
use of belief-desire-intention (BDI) agents in the test environment, to
increase the level of realism and human-like stimulation of simulated robots.
Artificial intelligence, such as agent theory, can be exploited for more
intelligent test generation. An automated testbench was implemented for a
simulation in Robot Operating System (ROS) and Gazebo, of a cooperative table
assembly task between a humanoid robot and a person. Requirements were verified
for this task, and some unexpected design issues were discovered, leading to
possible code improvements. Our results highlight the practicality of BDI
agents to automatically generate valid and human-like tests to get high code
coverage, compared to hand-written directed tests, pseudorandom generation, and
other variants of model-based test generation. Also, BDI agents allow the
coverage of combined behaviours of the HRI system with more ease than writing
temporal logic properties for model checking.


title: First-principles study of pyroelectricity in GaN and ZnO

abstract:
  First-principles calculations are made for the primary pyroelectric
coefficients of wurtzite GaN and ZnO. The pyroelectricity is attributed to the
quasiharmonic thermal shifts of internal strains (internal displacements of
cations and anions carrying their Born effective charges). The primary
(zero-external-strain) pyroelectricity dominates at low temperatures, while the
secondary pyroelectricity (the correction from external thermal strains)
becomes comparable with the primary pyroelectricity at high temperatures.
Contributions from the acoustic and the optical phonon modes to the primary
pyroelectric coefficient are only moderately well described by the
corresponding Debye function and Einstein function respectively.


title:
Nesting Depth of Operators in Graph Database Queries: Expressiveness Vs.
  Evaluation Complexity

abstract:
  Designing query languages for graph structured data is an active field of
research, where expressiveness and efficient algorithms for query evaluation
are conflicting goals. To better handle dynamically changing data, recent work
has been done on designing query languages that can compare values stored in
the graph database, without hard coding the values in the query. The main idea
is to allow variables in the query and bind the variables to values when
evaluating the query. For query languages that bind variables only once, query
evaluation is usually NP-complete. There are query languages that allow binding
inside the scope of Kleene star operators, which can themselves be in the scope
of bindings and so on. Uncontrolled nesting of binding and iteration within one
another results in query evaluation being PSPACE-complete.
  We define a way to syntactically control the nesting depth of iterated
bindings, and study how this affects expressiveness and efficiency of query
evaluation. The result is an infinite, syntactically defined hierarchy of
expressions. We prove that the corresponding language hierarchy is strict.
Given an expression in the hierarchy, we prove that it is undecidable to check
if there is a language equivalent expression at lower levels. We prove that
evaluating a query based on an expression at level i can be done in $\Sigma_i$
in the polynomial time hierarchy. Satisfiability of quantified Boolean formulas
can be reduced to query evaluation; we study the relationship between
alternations in Boolean quantifiers and the depth of nesting of iterated
bindings.


title:
The OCCASO survey: Presentation and radial velocities of twelve Milky
  Way Open Clusters

abstract:
  Open clusters (OCs) are crucial for studying the formation and evolution of
the Galactic disc. However, the lack of a large number of OCs analyzed
homogeneously hampers the investigations about chemical patterns and the
existence of Galactocentric radial and vertical gradients, or an
age-metallicity relation. To overcome this, we have designed the Open Cluster
Chemical Abundances from Spanish Observatories survey (OCCASO). We aim to
provide homogeneous radial velocities, physical parameters and individual
chemical abundances of six or more Red Clump stars for a sample of 25 old and
intermediate-age OCs visible from the Northern hemisphere. To do so, we use
high resolution spectroscopic facilities (R> 62,000) available at Spanish
observatories. We present the motivation, design and current status of the
survey, together with the first data release of radial velocities for 77 stars
in 12 OCs, which represents about 50% of the survey. We include clusters never
studied with high-resolution spectroscopy before (NGC~1907, NGC~6991,
NGC~7762), and clusters in common with other large spectroscopic surveys like
the Gaia-ESO Survey (NGC~6705) and APOGEE (NGC~2682 and NGC~6819). We perform
internal comparisons between instruments to evaluate and correct internal
systematics of the results, and compare our radial velocities with previous
determinations in the literature, when available. Finally, radial velocities
for each cluster are used to perform a preliminar kinematic study in relation
with the Galactic disc.


title:
The strict complementary slackness condition in linear fractional
  programming

abstract:
  The strict complementary slackness condition (SCSC) is an important concept
in the duality theory of linear programming (LP). The current study aims at
extending this concept to the framework of linear fractional programming (LFP).
First, we define this concept in this framework and demonstrate the existence
of a strict complementary solution - a pair of primal and dual optimal
solutions satisfying the SCSC. Second, we show that the problem of finding such
a solution reduces to that of identifying a relative interior point of a
polyhedron. More recently, Mehdiloozad et al. (2016) have addressed the latter
problem by proposing an LP problem. Using their proposed LP problem, we finally
develop two procedures for finding a strict complementary solution.


title: Elliptic boundary value problems with Gaussian white noise loads

abstract:
  Linear second order elliptic boundary value problems (BVP) on bounded
Lipschitz domains are studied in the case of Gaussian white noise loads.
Especially, Neumann and Robin BVPs are considered.
  The main obstacle for applying the usual variational approach is that the
Gaussian white noise has irregular realizations. In particular, the
corresponding Neumann boundary values are not well-defined in the ordinary
sense.
  In this work, the BVP is reformulated by replacing the continuity of the
boundary trace mapping with measurability. Instead of using variational methods
alone, the reformulation of the BVP derives also from Cameron-Martin space
techniques. The reformulation essentially returns the study of irregular white
noise loads to study of $L^2$-loads.
  Admissibility of the reformulation is demonstrated by showing that usual
finite element approximations of the BVP with discretized white noise loads
converge to the solution of the reformulated problem. For Neumann and Robin
BVPs, the finite dimensional approximations have been utilized before. However,
here also the infinite-dimensional limit is considered.


title: A Quasi-sure Non-degeneracy Property for the Brownian Rough Path

abstract:
  In the present paper, we are going to show that outside a slim set in the
sense of Malliavin (or quasi-surely), the signature path (which consists of
iterated path integrals in every degree) of Brownian motion is
non-self-intersecting. This property relates closely to a non-degeneracy
property for the Brownian rough path arising naturally from the uniqueness of
signature problem in rough path theory. As an important consequence we conclude
that quasi-surely, the Brownian rough path does not have any tree-like pieces
and every sample path of Brownian motion is uniquely determined by its
signature up to reparametrization.


title:
Unsupervised Watertight Mesh Generation for Physics Simulation
  Applications Using Growing Neural Gas on Noisy Free-Form Object Models

abstract:
  We present a framework to generate watertight mesh representations in an
unsupervised manner from noisy point clouds of complex, heterogeneous objects
with free-form surfaces. The resulting meshes are ready to use in applications
like kinematics and dynamics simulation where watertightness and fast
processing are the main quality criteria. This works with no necessity of user
interaction, mainly by utilizing a modified Growing Neural Gas technique for
surface reconstruction combined with several post-processing steps. In contrast
to existing methods, the proposed framework is able to cope with input point
clouds generated by consumer-grade RGBD sensors and works even if the input
data features large holes, e.g. a missing bottom which was not covered by the
sensor. Additionally, we explain a method to unsupervisedly optimize the
parameters of our framework in order to improve generalization quality and, at
the same time, keep the resulting meshes as coherent as possible to the
original object regarding visual and geometric properties.


title:
Constraining the density dependence of the symmetry energy using the
  multiplicity and average $p_T$ ratios of charged pions

abstract:
  The charged pion multiplicity ratio in intermediate energy heavy-ion
collisions, a probe of the density dependence of symmetry energy above the
saturation point, has been proven in a previous study to be extremely sensitive
to the strength of the isovector $\Delta$(1232) potential in nuclear matter. As
there is no knowledge, either from theory or experiment, about the magnitude of
this quantity, the extraction of constraints on the slope of the symmetry
energy at saturation by using exclusively the mentioned observable is hindered
at present. It is shown that, by including the ratio of average $p_T$ of
charged pions $\langle p_T^{(\pi^+)}\rangle/\langle p_T^{(\pi^-)}\rangle$ in
the list of fitted observables, the noted problem can be circumvented. A
realistic description of this observable requires accounting for the
interaction of pions with the dense nuclear matter environment by the
incorporation of the so called $S$-wave and $P$-wave pion optical potentials.
This is performed within the framework of a quantum molecular dynamics
transport model that enforces the conservation of the total energy of the
system. It is shown that constraints on the slope of the symmetry energy at
saturation density and the strength of the $\Delta$(1232) potential can be
simultaneously extracted. A symmetry energy with a value of the slope parameter
$L>$ 50 MeV is favored, at 1$\sigma$ confidence level, from a comparison with
published FOPI experimental data. A precise constraint will require
experimental data more accurate than presently available, particularly for the
charged pion multiplicity ratio, and better knowledge of the density and
momentum dependence of the pion potential for the whole range of these two
variables probed in intermediate energy heavy-ion collisions.


title:
Ab Initio Cycloidal and Chiral Magnetoelectric Responses in
  Cr$_{2}$O$_{3}$

abstract:
  We present a thorough density functional theory study of the magneto-electric
(ME) effect in Cr$_{2}$O$_{3}$. The spin-lattice ME tensor $\alpha$ was
determined in the low-field and spin flop (SF) phases, using the method of
dynamical magnetic charges, and found to be the sum of three distinct
components. Two of them, a large relativistic "cycloidal" term and a small
longitudinal term, are independent on the spin orientation. The third, only
active in the SF phases is also of relativistic origin and arises from
magnetic-field-induced chirality, leading to a non-toroidal ME response.


title:
Counting indices of critical points of rank two of polynomial selfmaps
  of R^4

abstract:
  There is shown how to compute the sum of indices of critical points of rank
two for polynomial selmaps of R^4


title: How sticky is the chaos/order boundary?

abstract:
  In dynamical systems with divided phase space, the vicinity of the boundary
between regular and chaotic regions is often "sticky," that is, trapping orbits
from the chaotic region for long times. Here, we investigate the stickiness in
the simplest mushroom billiard, which has a smooth such boundary, but
surprisingly subtle behaviour. As a measure of stickiness, we investigate P(t),
the probability of remaining in the mushroom cap for at least time t given
uniform initial conditions in the chaotic part of the cap. The stickiness is
sensitively dependent on the radius of the stem r via the Diophantine
properties of rho = (2/\pi) arccos r. Almost all rho give rise to families of
marginally unstable periodic orbits (MUPOs) where P(t) ~ C/t, dominating the
stickiness of the boundary. Here we consider the case where rho is MUPO-free
and has continued fraction expansion with bounded partial quotients. We show
that t^2 P(t) is bounded, varying infinitely often between values whose ratio
is at least 32/27. When rho has an eventually periodic continued fraction
expansion, that is, a quadratic irrational, t^2 P(t) converges to a
log-periodic function. In general, we expect less regular behaviour, with upper
and lower exponents lying between 1 and 2. The results may shed light on the
parameter dependence of boundary stickiness in annular billiards and generic
area preserving maps.


title:
POD-Galerkin reduced-order modeling with adaptive finite element
  snapshots

abstract:
  We consider model order reduction by proper orthogonal decomposition (POD)
for parametrized partial differential equations, where the underlying snapshots
are computed with adaptive finite elements. We address computational and
theoretical issues arising from the fact that the snapshots are members of
different finite element spaces. We propose a method to create a POD-Galerkin
model without interpolating the snapshots onto their common finite element
mesh. The error of the reduced-order solution is not necessarily Galerkin
orthogonal to the reduced space created from space-adapted snapshot. We analyze
how this influences the error assessment for POD-Galerkin models of linear
elliptic boundary value problems. As a numerical example we consider a
two-dimensional convection-diffusion equation with a parametrized convective
direction. To illustrate the applicability of our techniques to non-linear
time-dependent problems, we present a test case of a two-dimensional viscous
Burgers equation with parametrized initial data.


title: Typical fast thermalization processes in closed many-body systems

abstract:
  Lack of knowledge about the detailed many-particle motion on the microscopic
scale is a key issue in any theoretical description of a macroscopic
experiment. For systems at or close to thermal equilibrium, statistical
mechanics provides a very successful general framework to cope with this
problem. Far from equilibrium, only very few quantitative and comparably
universal results are known. Here, a new quantum mechanical prediction of this
type is derived and verified against various experimental and numerical data
from the literature. It quantitatively describes the entire temporal relaxation
towards thermal equilibrium for a large class (in a mathematically precisely
defined sense) of closed many-body systems, whose initial state may be
arbitrarily far from equilibrium.


title:
From neurons to epidemics: How trophic coherence affects spreading
  processes

abstract:
  Trophic coherence, a measure of the extent to which the nodes of a directed
network are organised in levels, has recently been shown to be closely related
to many structural and dynamical aspects of complex systems, including graph
eigenspectra, the prevalence or absence of feed-back cycles, and linear
stability. Furthermore, non-trivial trophic structures have been observed in
networks of neurons, species, genes, metabolites, cellular signalling,
concatenated words, P2P users, and world trade. Here we consider two simple yet
apparently quite different dynamical models -- one a
Susceptible-Infected-Susceptible (SIS) epidemic model adapted to include
complex contagion, the other an Amari-Hopfield neural network -- and show that
in both cases the related spreading processes are modulated in similar ways by
the trophic coherence of the underlying networks. To do this, we propose a
network assembly model which can generate structures with tunable trophic
coherence, limiting in either perfectly stratified networks or random graphs.
We find that trophic coherence can exert a qualitative change in spreading
behaviour, determining whether a pulse of activity will percolate through the
entire network or remain confined to a subset of nodes, and whether such
activity will quickly die out or endure indefinitely. These results could be
important for our understanding of phenomena such as epidemics, rumours, shocks
to ecosystems, neuronal avalanches, and many other spreading processes.


title:
Distributed Spectral Efficiency Maximization in Full-Duplex Cellular
  Networks

abstract:
  Three-node full-duplex is a promising new transmission mode between a
full-duplex capable wireless node and two other wireless nodes that use
half-duplex transmission and reception respectively. Although three-node
full-duplex transmissions can increase the spectral efficiency without
requiring full-duplex capability of user devices, inter-node interference - in
addition to the inherent self-interference - can severely degrade the
performance. Therefore, as methods that provide effective self-interference
mitigation evolve, the management of inter-node interference is becoming
increasingly important. This paper considers a cellular system in which a
full-duplex capable base station serves a set of half-duplex capable users. As
the spectral efficiencies achieved by the uplink and downlink transmissions are
inherently intertwined, the objective is to device channel assignment and power
control algorithms that maximize the weighted sum of the uplink-downlink
transmissions. To this end a distributed auction based channel assignment
algorithm is proposed, in which the scheduled uplink users and the base station
jointly determine the set of downlink users for full-duplex transmission.
Realistic system simulations indicate that the spectral efficiency can be up to
89% better than using the traditional half-duplex mode. Furthermore, when the
self-interference cancelling level is high, the impact of the user-to-user
interference is severe unless properly managed.


title:
Weighted distribution of points on cyclic covers of the projective line
  over finite fields

abstract:
  Given a finite field $\mathbb{F}_{q}$, we study the distribution of the
number of $\mathbb{F}_{q}$-points on (possibly singular) affine curves given by
the polynomial equations of the form $C_{f} : y^{m} = f(x)$, where $f$ is
randomly chosen from a fixed collection $\mathcal{F}(\mathbb{F}_{q})$ of
polynomials in $\mathbb{F}_{q}[x]$ with fixed $m \geq 2$. Under some
conditions, these equations are affine models of cyclic $m$-covers of the
projective line. Previously, different authors obtained asymptotic results
about distributions of points on curves associated to certain collections of
polynomials $f$ defined by large degree of $f$ or large genus of the smooth,
projective, and geometrically irreducible curves $\tilde{C}_{f}$ obtained from
the affine equations $C_{f}$, when the degree or genus goes to infinity. We
summarize their strategies as a lemma, which gives a sufficient condition on
the number of polynomials in a fixed collection $\mathcal{F}(\mathbb{F}_{q})$
with prescribed values, that automatically gives the distribution of points on
the affine curves associated to the collection. We give infinitely many new
examples of collections $\mathcal{F}(\mathbb{F}_{q})$ which satisfy the
sufficient condition and hence produce infinitely many new distributions when a
certain invariant goes to infinity. The main object of this paper is to
demonstrate how changing the invariant that one takes to infinity changes the
resulting distribution of points on curves.


title: Eventually stable rational functions

abstract:
  For a field K, rational function phi in K(z) of degree at least two, and
alpha in P^1(K), we study the polynomials in K[z] whose roots are given by the
solutions to phi^n(z) = alpha, where phi^n denotes the nth iterate of phi. When
the number of irreducible factors of these polynomials stabilizes as n grows,
the pair (phi, alpha) is called eventually stable over K. We conjecture that
(phi, alpha) is eventually stable over K when K is any global field and alpha
any point not periodic under phi (an additional non-isotriviality hypothesis is
necessary in the function field case). We prove the conjecture when K has a
discrete valuation for which (1) phi has good reduction and (2) phi acts
bijectively on all finite residue extensions. As a corollary, we prove for
these maps a conjecture of Sookdeo on the finiteness of S-integral points in
backwards orbits. We also give several characterizations of eventual stability
in terms of natural finiteness conditions, and survey previous work on the
phenomenon.


title:
Difference analogue of Cartan's Second Main Theorem for slowly moving
  periodic targets

abstract:
  We extend the difference analogue of Cartan's second main theorem for the
case of slowly moving periodic hyperplanes, and introduce two different natural
ways to find a difference analogue of the truncated second main theorem. As
applications, we obtain a new Picard type theorem and difference analogues of
the deficiency relation for holomorphic curves.


title: The Rotating Rayleigh-Taylor Instability

abstract:
  The effect of rotation upon the classical two-layer Rayleigh-Taylor
instability is considered theoretically and compared with previous experimental
results. In particular we consider a two-layer system with an axis of rotation
that is perpendicular to the interface between the layers. In general we find
that a wave mode's growth rate may be reduced by rotation. We further show that
in some cases, unstable axisymmetric wave modes may be stabilized by rotating
the system above a critical rotation rate associated with the mode's
wavelength, the Atwood number and the flow's aspect ratio. We compare our
theory with experiments conducted in a magnetic field using 'heavy' diamagnetic
and 'light' paramagnetic fluids and present comparisons between the theoretical
predictions and experimental observations.


title:
Annual Cosmic Ray Spectra from 250 MeV up to 1.6 GeV from 1995 - 2014
  Measured With the Electron Proton Helium Instrument onboard SOHO

abstract:
  The solar modulation of galactic cosmic rays (GCR) can be studied in detail
by examining long-term variations of the GCR energy spectrum (e.g. on the
scales of a solar cycle). With almost 20 years of data, the Electron Proton
Helium INstrument (EPHIN) onboard the SOlar and Heliospheric Observatory (SOHO)
is well suited for this kind of investigation. Although the design of the
instrument is optimized to measure proton and helium isotope spectra up to 50
MeV nucleon$^{-1}$ , the capability exists to determine proton energy spectra
from 250 MeV up to above 1.6 GeV. Therefore we developed a sophisticated
inversion method to calculate such proton spectra. The method relies on a
GEANT4 Monte Carlo simulation of the instrument and a simplified spacecraft
model that calculates the energy-response function of EPHIN for electrons,
protons and heavier ions. For validation purposes, proton spectra based on this
method are compared to various balloon missions and space instrumentation. As a
result we present annual galactic cosmic ray spectra from 1995 to 2014.


title: Karhunen-Loeve expansions of Levy processes

abstract:
  Karhunen-Loeve expansions (KLE) of stochastic processes are important tools
in mathematics, the sciences, economics, and engineering. However, the KLE is
primarily useful for those processes for which we can identify the necessary
components, i.e., a set of basis functions, and the distribution of an
associated set of stochastic coefficients. Our ability to derive these
components explicitly is limited to a handful processes. In this paper we
derive all the necessary elements to implement the KLE for a square-integrable
Levy process. We show that the eigenfunctions are sine functions, identical to
those found in the expansion of a Wiener process. Further, we show that
stochastic coefficients have a jointly infinitely divisible distribution, and
we derive the generating triple of the first d coefficients. We also show,
that, in contrast to the case of the Wiener process, the coefficients are not
independent unless the process has no jumps. Despite this, we develop a series
representation of the coefficients which allows for simulation of any process
with a strictly positive Levy density. We implement our theoretical results by
simulating the KLE of a variance gamma process.


title: T-dual RR couplings on D-branes from S-matrix elements

abstract:
  Using the linear T-dual ward identity associated with the NSNS gauge
transformations, some RR couplings on D$_p$-branes have been found at order
$O(\alpha'^2)$. We examine the $C^{(p-1)}$ couplings with the S-matrix elements
of one RR, one graviton and one antisymmetric B-field vertex operators. We find
the consistency of T-dual S-matrix elements and explicit results of scattering
string amplitude and show that the string amplitude reproduces these couplings
as well as some other couplings. This illustration is found for $C^{(p-3)}$
couplings in the literature which is extended to the $C^{(p-1)}$ couplings in
this paper.


title:
Fitting peculiar spectral profiles in He I 10830 \r{A} absorption
  features

abstract:
  The new generation of solar instruments provides better spectral, spatial,
and temporal resolution for a better understanding of the physical processes
that take place on the Sun. Multiple-component profiles are more commonly
observed with these instruments. Particularly, the He I 10830 \r{A} triplet
presents such peculiar spectral profiles, which give information on the
velocity and magnetic fine structure of the upper chromosphere. The purpose of
this investigation is to describe a technique to efficiently fit the two
blended components of the He I 10830 \r{A} triplet, which are commonly observed
when two atmospheric components are located within the same resolution element.
The observations used in this study were taken on 2015 April 17 with the very
fast spectroscopic mode of the GREGOR Infrared Spectrograph (GRIS) attached to
the 1.5-meter GREGOR solar telescope, located at the Observatorio del Teide,
Tenerife, Spain. We apply a double-Lorentzian fitting technique using
Levenberg-Marquardt least-squares minimization. This technique is very simple
and much faster than inversion codes. Line-of-sight Doppler velocities can be
inferred for a whole map of pixels within just a few minutes. Our results show
sub- and supersonic downflow velocities of up to 32 km/s for the fast component
in the vicinity of footpoints of filamentary structures. The slow component
presents velocities close to rest.


title: Markovian semigroup from non-Markovian evolutions

abstract:
  It is shown that a convex combination of two non-Markovian evolutions may
lead to Markovian semigroup. This shows that convex combination of quantum
evolutions displaying nontrivial memory effects may result in a perfectly
memoryless evolution.


title: The Bi-periodic Fibonacci Octonions

abstract:
  In this paper, by using bi-periodic Fibonacci numbers, we introduce the
bi-periodic Fibonacci octonions. After that, we derive the generating function
of these octonions as well as investigated some properties over them. Also, as
another main result of this paper, we give the summations for bi-periodic
Fibonacci octonions.


title: Maxwell's demon and information channel width of a black hole

abstract:
  Using a new generalized second law of thermodynamics, the information and
entropy of a black hole and its accretion disk are analyzed respectively. We
find the bound of the information channel width of a black hole, which is
determined by the variation rate of the horizon temperature and the mass of the
black hole's shell(the accretion disk close to the horizon).


title:
Tunable inverse topological heterostructure utilizing
  $(Bi_{1-x}In_{x})_{2}Se_{3}$

abstract:
  In typical topological insulator (TI) systems the TI is bordered by a non-TI
insulator, and the surrounding conventional insulators, including vacuum, are
not generally treated as part of the TI system. Here, we implement the first
material system where the roles are reversed, and the TSS form around the
non-TI (instead of the TI) layers. This is realized by growing a layer of the
tunable non-TI $(Bi_{1-x}In_{x})_{2}Se_{3}$ in between two layers of the TI
$Bi_2Se_3$ using the atomically-precise molecular beam epitaxy technique. On
this tunable inverse topological platform, we systematically vary the thickness
and the composition of the $(Bi_{1-x}In_{x})_{2}Se_{3}$ layer and show that
this tunes the coupling between the TI layers from strongly-coupled metallic to
weakly-coupled, and finally to a fully-decoupled insulating regime. This system
can be used to probe the fundamental nature of coupling in TI materials and
provides a tunable insulating layer for TI devices.


title: A random model for the Paley graph

abstract:
  For a prime $p$ we define the Paley graph to be the graph with the set of
vertices $\mathbb{Z}/p\mathbb{Z}$, and with edges connecting vertices whose sum
is a quadratic residue. Paley graphs are notoriously difficult to study,
particularly finding bounds for their clique numbers. For this reason, it is
desirable to have a random model. A well known result of Graham and Ringrose
shows that the clique number of the Paley graph is $\Omega(\log p\log\log\log
p)$ (even $\Omega(\log p\log\log p)$, under the generalized Riemann hypothesis)
for infinitely many primes $p$ -- a behaviour not detected by the random Cayley
graph which is hence deficient as a random model for for the Paley graph. In
this paper we give a new probabilistic model which incorporates some
multiplicative structure and as a result captures the Graham-Ringrose
phenomenon. We prove that if we sample such a random graph independently for
every prime, then almost surely (i) for infinitely many primes $p$ the clique
number is $\Omega(\log p\log\log p)$, whilst (ii) for almost all primes the
clique number is $(2+o(1))\log p$.


title:
Tagged spectator deep-inelastic scattering off the deuteron as a tool to
  study neutron structure

abstract:
  We give an overview of a model to describe deep-inelastic scattering (DIS)
off the deuteron with a spectator proton, based on the virtual nucleon
approximation (VNA). The model accounts for the final-state interactions (FSI)
of the DIS debris with the spectator proton. Values of the rescattering cross
section are obtained by fits to high-momentum spectator data. By using the
so-called "pole extrapolation method", free neutron structure functions can be
obtained by extrapolating low-momentum spectator proton data to the on-shell
neutron pole. We apply this method to the BONuS data set and find a surprising
Bjorken $x$ dependence, indicating a possible rise of the neutron to proton
structure function ratio at high $x$.


title:
Beating the Shot-Noise Limit with Sources of Partially-Distinguishable
  Photons

abstract:
  Quantum metrology promises high-precision measurements beyond the capability
of any classical techniques, and has the potential to be integral to
investigative techniques. However, all sensors must tolerate imperfections if
they are to be practical. Here we show that photons with perfectly overlapped
modes, which are therefore fully indistinguishable, are not required for
quantum-enhanced measurement, and that partially-distinguishable photons do not
have to be engineered to mitigate the adverse effects of distinguishability. We
quantify the effect of distinguishability on quantum metrology experiments, and
report results of an experiment to verify that two- and four-photon states
containing partially-distinguishable photons can achieve quantum-enhanced
sensitivity with low-visibility quantum interference. This demonstrates that
sources producing photons with mixed spectral states can be readily utilized
for quantum metrology.


title: Symmetry-constrained electron vortex propagation

abstract:
  Electron vortex beams hold great promise for development in transmission
electron microscopy, but have yet to be widely adopted. This is partly due to
the complex set of interactions that occur between a beam carrying orbital
angular momentum (OAM) and a sample. Herein, the system is simplified to focus
on the interaction between geometrical symmetries, OAM and topology. We present
multiple simulations, alongside experimental data to study the behaviour of a
variety of electron vortex beams after interacting with apertures of different
symmetries, and investigate the effect on their OAM and vortex structure, both
in the far-field and under free-space propagation.


title: Global effects on neoclassical transport in the pedestal with impurities

abstract:
  We present a numerical study of collisional transport in a tokamak pedestal
in the presence of non-trace impurities, using the radially global $\delta f$
neoclassical solver PERFECT [M. Landreman et al. 2014 Plasma Phys. Control.
Fusion 56 045005]. It is known that in a tokamak core with non-trace impurities
present the radial impurity flux opposes the bulk ion flux to provide an
ambipolar particle transport, with the electron transport being negligibly
small. However, in a sharp density pedestal with sub-sonic ion flows the
electron transport can be comparable to the ion and impurity flows.
Furthermore, the neoclassical particle transport is not intrinsically
ambipolar, and the non-ambipolarity of the fluxes extends outside the pedestal
region by the radial coupling of the perturbations. The neoclassical momentum
transport, which is finite in the presence of ion orbit-width scale profile
variations, is significantly enhanced when impurities are present in non-trace
quantities, even if the total parallel mass flow is dominated by the bulk ions.


title: On a class of formal power series and their summability

abstract:
  A family of formal power series, such that its coefficients satisfy a
recursion formula, is characterized in terms of the summability, in the sense
of J. P. Ramis, of its elements along certain well chosen directions. We
describe a set of ordinary differential equations which have, as a formal
solution, one of such formal power series, and also describe the actual
solutions which own such formal power series as Gevrey asymptotic expansion.
  The main results are extended into the framework of $q-$Gevrey series and
$q-$difference equations, and also to the case of moment-differential
equations, whose formal solutions have their coefficients' growth governed by a
so-called strongly regular sequence, appearing as a generalization of the
Gevrey-like sequences.


title: Toroidal Dimer Model and Temperley's Bijection

abstract:
  Temperley's bijection relates the toroidal dimer model to cycle rooted
spanning forests ($CRSF$) on the torus. The height function of the dimer model
and the homology class of $CRSF$ are naturally related. When the size of the
torus tends to infinity, we show that the measure on $CRSF$ arising from the
dimer model converges to a measure on (disconnected) spanning forests or
spanning trees. There is a phase transition, which is determined by the average
height change.


title: An exotic group as limit of finite special linear groups

abstract:
  We consider the Polish group obtained as the rank-completion of an inductive
limit of finite special linear groups. This Polish group is topologically
simple modulo its center, it is extremely amenable and has no non-trivial
strongly continuous unitary representation on a Hilbert space.


title:
Probing Neutrino Mass Hierarchy by Comparing the Charged-Current and
  Neutral-Current Interaction Rates of Supernova Neutrinos

abstract:
  The neutrino mass hierarchy is one of the neutrino fundamental properties yet
to be determined. We introduce a method to determine neutrino mass hierarchy by
comparing the interaction rate of neutral current (NC) interactions,
$\nu(\hat{\nu}) + p\rightarrow\nu(\hat{\nu}) + p$, and inverse beta decays
(IBD), $\bar{\nu}_e + p\rightarrow n + e^+$, of supernova neutrinos in
scintillation detectors. Neutrino flavor conversions inside the supernova are
sensitive to neutrino mass hierarchy. Due to Mikheyev-Smirnov-Wolfenstein
effects, the full swapping of $\bar{\nu}_e$ flux with the $\bar{\nu}_x$
($x=\mu,~\tau$) one occurs in the inverted hierarchy, while such a swapping
does not occur in the normal hierarchy. As a result, more high energy IBD
events occur in the detector for the inverted hierarchy than the high energy
IBD events in the normal hierarchy. By comparing IBD interaction rate with the
mass hierarchy independent NC interaction rate, one can determine the neutrino
mass hierarchy.


title:
The electronic structure of palladium in the presence of many-body
  effects

abstract:
  Including on-site electronic interactions described by the multi-orbital
Hubbard model we study the correlation effects in the electronic structure of
bulk palladium. We use a combined density functional and dynamical mean field
theory, LDA+DMFT, based on the fluctuation exchange approximation. The
agreement between the experimentally determined and the theoretical lattice
constant and bulk modulus is improved when correlation effects are included. It
is found that correlations modify the Fermi surface around the neck at the
$L$-point while the Fermi surface tube structures show little correlation
effects. At the same time we discuss the possibility of satellite formation in
the high energy binding region. Spectral functions obtained within the LDA+DMFT
and $GW$ methods are compared to discuss non-local correlation effects. For
relatively weak interaction strength of the local Coulomb and exchange
parameters spectra from LDA+DMFT shows no major difference in comparison to
$GW$.


title: Ferromagnetic resonance in submicron permalloy stripes

abstract:
  We present the results of systematic experimental investigations and
micromagnetic simulations for the ferromagnetic resonance in rectangular
permalloy microstripes. It is shown that the resonant magnetization
oscillations have a complex spatial structure including a quasi-homogeneous
precession, lateral spin-wave resonances and localized edge modes, which
strongly depend on sample orientation in an external magnetic field.


title:
Automated image segmentation and division plane detection in single live
  Staphylococcus aureus cells

abstract:
  Staphylococcus aureus is a coccal bacterium, which divides by binary fission.
After division the cells remain attached giving rise to small clusters, with a
characteristic 'bunch of grapes' morphology. S. aureus is an important human
pathogen and this, combined with the increasing prevalence of
antibiotic-resistant strains, such as Methicillin Resistant S. aureus (MRSA),
make it an excellent subject for studies of new methods of antimicrobial
action. Many antibiotics, such as penicillin, prevent S. aureus cell division
and so an understanding of this fundamental process may pave the way to the
identification of novel drugs. We present here a novel image analysis framework
for automated detection and segmentation of cells in S. aureus clusters, and
identification of their cell division planes. We demonstrate the technique on
GFP labelled EzrA, a protein that localises to a mid-cell plane during division
and is involved in regulation of cell size and division. The algorithms may
have wider applicability in detecting morphologically complex structures of
fluorescently-labelled proteins within cells in other cell clusters.


title:
Finding Relationships between Socio-Technical Aspects and Personality
  Traits by Mining Developer E-mails

abstract:
  Personality traits influence most, if not all, of the human activities, from
those as natural as the way people walk, talk, dress and write to those most
complex as the way they interact with others. Most importantly, personality
influences the way people make decisions including, in the case of developers,
the criteria they consider when selecting a software project they want to
participate. Most of the works that study the influence of social, technical
and human factors in software development projects have been focused on the
impact of communications in software quality. For instance, on identifying
predictors to detect files that may contain bugs before releasing an enhanced
version of a software product. Only a few of these works focus on the analysis
of personality traits of developers with commit permissions (committers) in
Free/Libre and Open-Source Software projects and their relationship with the
software artifacts they interact with. This paper presents an approach, based
on the automatic recognition of personality traits from e-mails sent by
committers in FLOSS projects, to uncover relationships between the social and
technical aspects that occur during the software development process. Our
experimental results suggest the existence of some relationships among
personality traits projected by the committers through their e-mails and the
social (communication) and technical activities they undertake. This work is a
preliminary study aimed at supporting the setting up of efficient work teams in
software development projects based on an appropriate mix of stakeholders
taking into account their personality traits.


title: Spectral Theorem for quaternionic normal operators: Multiplication form

abstract:
  Let $\mathcal{H}$ be a right quaternionic Hilbert space and let $T$ be a
quaternionic normal operator with the domain $\mathcal{D}(T) \subset
\mathcal{H}$. Then for a fixed unit imaginary quaternion $m$, there exists a
Hilbert basis $\mathcal{N}_{m}$ of $\mathcal{H}$, a measure space $(\Omega,
\mu)$, a unitary operator $U \colon \mathcal{H} \to L^{2}(\Omega; \mathbb{H};
\mu)$ and a $\mu$ - measurable function $\phi \colon \Omega \to \mathbb{C}_m$
(here $\mathbb{C}_{m} = \{\alpha + m \beta; \;\alpha, \beta \in \mathbb{R}\}$)
such that \[ Tx = U^{*}M_{\phi}Ux, \; \mbox{for all}\; x\in \mathcal{D}(T), \]
where $M_{\phi}$ is the multiplication operator on $L^{2}(\Omega; \mathbb{H};
\mu)$ induced by $\phi$ with $ U(\mathcal{D}(T)) \subseteq
\mathcal{D}(M_{\phi})$. In the process, we prove that every complex Hilbert
space is a slice Hilbert space.
  We establish these results by reducing it to the complex case then lift it to
the quaternionic case.


title:
Label-free optical quantification of structural alterations in
  Alzheimer's disease

abstract:
  We present a quantitative label-free imaging of mouse whole brain tissue
slices with sub-micrometre resolution, employing holographic microscopy and an
automated scanning platform. From the measured light field images, scattering
coefficients and anisotropies are quantitatively retrieved, which enables
access to structural information about brain tissues. As a proof of principle,
we demonstrate that these scattering parameters enable us to quantitatively
address structural alteration in the brain tissues of mice with Alzheimer's
disease.


title:
Observational constraints and diagnostics for time-dependent dark energy
  models

abstract:
  In this paper, we constrain four time-dependent dark energy (TDDE) models by
using the Type Ia supernovae (SNe Ia), baryonic acoustic oscillations (BAO),
observational Hubble parameter (OHD) data-sets as well as the single data point
from the newest event GW150914. Subsequently, adopting the best fitting values
of the model parameters, we apply the original statefinder, statefinder
hierarchy, the growth rate of matter perturbations and $Om(z)$ diagnostics to
distinguish the TDDE scenarios and the $\Lambda$CDM scenario from each other.
We discover that all the TDDE models and $\Lambda$CDM model can be
distinguished better at the present epoch by using the statefinder hierarchy
than using the original statefinder, the growth rate of matter perturbations
and $Om(z)$ diagnostics, especially, in the planes of
$\{S_3^{(1)},S_4^{(1)}\}$, $\{S_3^{(2)},S_4^{(2)}\}$, $\{S_5^{(1)},S_5^{(2)}\}$
and $\{S_4^{(2)},S_5^{(2)}\}$.


title: Prolongation of Tanaka structures: an alternative approach

abstract:
  The classical theory of prolongation of G-structures was generalized by N.
Tanaka to a wide class of geometric structures (Tanaka structures), which are
defined on a non-holonomic distribution. Examples of Tanaka structures include
subriemannian, subconformal, CR-structures, structures associated to second
order differential equations and structures defined by gradings of Lie algebras
(in the setting of parabolic geometry). Tanaka's prolongation procedure
associates to a Tanaka structure of finite order a manifold with an absolute
parallelism. It is a very fruitful method for the description of local
invariants, investigation of the automorphism group and the equivalence
problem. In this paper we develop an alternative constructive approach for
Tanaka's prolongation procedure, based on the theory of quasi-gradations in
filtered vector spaces, G-structures and their torsion functions.


title:
Stellar laboratories. VII. New Kr IV - VII oscillator strengths and an
  improved spectral analysis of the hot, hydrogen-deficient DO-type white dwarf
  RE0503-289

abstract:
  For the spectral analysis of high-resolution and high-signal-to-noise (S/N)
spectra of hot stars, state-of-the-art non-local thermodynamic equilibrium
(NLTE) model atmospheres are mandatory. These are strongly dependent on the
reliability of the atomic data that is used for their calculation.
  New of Kr IV - VII oscillator strengths for a large number of lines allow to
construct more detailed model atoms for our NLTE model-atmosphere calculations.
This enables us to search for additional Kr lines in observed spectra and to
improve Kr abundance determinations.
  We calculated Kr IV - VII oscillator strengths to consider radiative and
collisional bound-bound transitions in detail in our NLTE stellar-atmosphere
models for the analysis of Kr lines exhibited in high-resolution and high-S/N
ultraviolet (UV) observations of the hot white dwarf RE 0503-289.
  We reanalyzed the effective temperature and surface gravity and determined
Teff = 70 000 +/- 2000 K and log (g / cm/s**2) = 7.5 +/- 0.1. We newly
identified ten Kr V lines and one Kr VI line in the spectrum of RE 0503-289. We
measured a Kr abundance of -3.3 +/- 0.3 (logarithmic mass fraction). We
discovered that the interstellar absorption toward RE 0503-289 has a
multi-velocity structure within a radial-velocity interval of -40 km/s < vrad <
+18 km/s.
  Reliable measurements and calculations of atomic data are a prerequisite for
state-of-the-art NLTE stellar-atmosphere modeling. Observed Kr V - VII line
profiles in the UV spectrum of the white dwarf RE 0503-289 were simultaneously
well reproduced with our newly calculated oscillator strengths.


title:
On the monodromies and the limit mixed Hodge structures of families of
  algebraic varieties

abstract:
  We study the monodromies and the limit mixed Hodge structures of families of
complete intersection varieties over a punctured disk in the complex plane. For
this purpose, we express their motivic nearby fibers in terms of the geometric
data of some Newton polyhedra. In particular, the limit mixed Hodge numbers and
some part of the Jordan normal forms of the monodromies of such a family will
be described very explicitly.


title: Turbophoresis in forced inhomogeneous turbulence

abstract:
  We show, by direct numerical simulations, that heavy inertial particles
(characterized by Stokes number $\St$) in inhomogeneously forced statistically
stationary isothermal turbulent flows cluster at the minima of mean-square
turbulent velocity. Two turbulent transport processes, turbophoresis and
turbulent diffusion together determine the spatial distribution of the
particles. If the turbulent diffusivity is assumed to scale with turbulent root
mean square velocity, as is the case for homogeneous turbulence, the
turbophoretic coefficient can be calculated. Indeed, for the above assumption,
the non-dimensional product of the turbophoretic coefficient and the rms
velocity is shown to increase with $St$ for small $St$, reach a maxima for
$St\approx 10$ and decrease as $\sim St^{-0.33}$ for large $St$.


title: Classical origin of conductance oscillations in an integrable cavity

abstract:
  Scanning gate microscopy measurements in a circular ballistic cavity with a
tip placed near its center yield a non-monotonic dependence of the conductance
on the tip voltage. Detailed numerical quantum calculations reproduce these
conductance oscillations, and a classical scheme leads to its physical
understanding. The large-amplitude conductance oscillations are shown to be of
classical origin, and well described by the effect of a particular class of
short trajectories.


title: Extrinsic Proton NMR Studies of Mg(OH)$_2$ and Ca(OH)$_2$

abstract:
  We studied narrow $^1$H NMR spectra of Mg(OH)$_2$ and Ca(OH)$_2$ powders at
100$-$355 K and 42$-$59 MHz using pulsed NMR techniques. The Fourier
transformed NMR spectra of the proton free-induction signals show the
superposition of broad and narrow components, which can be assigned to immobile
protons and extrinsic mobile protons, respectively. We found that a narrow
spectrum develops on heating above about $T_c$ = 260 K and widens above a
Larmor frequency of about $f_c$ = 50 MHz for Mg(OH)$_2$. The
temperature-induced NMR spectrum and the characteristic frequency $f_c$ of 50
MHz are the noteworthy features of the nuclear spin fluctuation spectra of the
extrinsic protons.


title: The Monge-Amp\`ere equation for non-integrable almost complex structures

abstract:
  We show existence and uniqueness of solutions to the Monge-Ampere equation on
compact almost complex manifolds with non-integrable almost complex structure.


title:
A Security Analysis and Revised Security Extension for the Precision
  Time Protocol

abstract:
  The Precision Time Protocol (PTP) aims to provide highly accurate and
synchronised clocks. Its defining standard, IEEE 1588, has a security section
("Annex K") which relies on symmetric-key secrecy. In this paper we present a
detailed threat analysis of the PTP standard, in which we highlight the
security properties that should be addressed by any security extension. During
this analysis we identify a sequence of new attacks and non-cryptographic
network-based defenses that mitigate them. We then suggest to replace Annex K's
symmetric cryptography by an efficient elliptic-curve Public-Key signatures. We
implemented all our attacks to demonstrate their effectiveness, and also
implemented and evaluated both the network and cryptographic defenses. Our
results show that the proposed schemes are extremely practical, and much more
secure than previous suggestions.


title:
Could the observation of $X(5568)$ be resulted by the near threshold
  rescattering effects?

abstract:
  We investigate the invariant mass distributions of $B_s\pi$ via different
rescattering processes. Because the triangle singularity (TS) could be present
for a very broad incident energy region, it can be expected that the TS peaks
may simulate the resonance-like bump $X(5568)$ observed by the D0
collaboration. The highly process-dependent characteristic of TS mechanism
offers a criterion to distinguish it from other dynamic mechanisms.


title: Probabilistic Relational Model Benchmark Generation

abstract:
  The validation of any database mining methodology goes through an evaluation
process where benchmarks availability is essential. In this paper, we aim to
randomly generate relational database benchmarks that allow to check
probabilistic dependencies among the attributes. We are particularly interested
in Probabilistic Relational Models (PRMs), which extend Bayesian Networks (BNs)
to a relational data mining context and enable effective and robust reasoning
over relational data. Even though a panoply of works have focused, separately ,
on the generation of random Bayesian networks and relational databases, no work
has been identified for PRMs on that track. This paper provides an algorithmic
approach for generating random PRMs from scratch to fill this gap. The proposed
method allows to generate PRMs as well as synthetic relational data from a
randomly generated relational schema and a random set of probabilistic
dependencies. This can be of interest not only for machine learning researchers
to evaluate their proposals in a common framework, but also for databases
designers to evaluate the effectiveness of the components of a database
management system.


title:
Following fluctuating signs: anomalous active superdiffusion of swimmers
  in anisotropic media

abstract:
  Active (i.e., self-propelled or swimming) particles moving through an
isotropic fluid exhibit conventional diffusive behavior. We report anomalous
diffusion of an active particle moving in an anisotropic, nematic background.
Whilst the translational motion parallel to the nematic director shows
ballistic behavior, the long-time transverse motion is super-diffusive, with an
anomalous scaling $\propto t \ln t$ of the mean squared displacement with time
$t$. This behavior is predicted by an analytical theory that we present here,
and is corroborated by numerical simulation of active particle diffusion in a
simple lattice model for a nematic liquid crystal. It is universal for any
collection of self-propelled elements (e.g., bacteria or active rods) moving in
a nematic background, provided only that the swimmers are sufficiently dilute
that their interactions with each other can be neglected, and that they do not
perform "hairpin" turns.


title: Explicit isogenies in quadratic time in any characteristic

abstract:
  Consider two elliptic curves $E,E'$ defined over the finite field
$\mathbb{F}_q$, and suppose that there exists an isogeny $\psi$ between $E$ and
$E'$. We propose an algorithm that determines $\psi$ from the knowledge of $E$,
$E'$ and of its degree $r$, by using the structure of the $\ell$-torsion of the
curves (where $\ell$ is a prime different from the characteristic $p$ of the
base field). Our approach is inspired by a previous algorithm due to
Couveignes, that involved computations using the $p$-torsion on the curves. The
most refined version of that algorithm, due to De Feo, has a complexity of
$\tilde{O}(r^2) p^{O(1)}$ base field operations. On the other hand, the cost of
our algorithm is $\tilde{O}(r^2 + \sqrt{r} \log(q))$; this makes it an
interesting alternative for the medium- and large-characteristic cases.


title: Exact Event Horizon of a Black Hole Merger

abstract:
  We argue that the event horizon of a binary black hole merger, in the
extreme-mass-ratio limit where one of the black holes is much smaller than the
other, can be described in an exact analytic way. This is done by tracing in
the Schwarzschild geometry a congruence of null geodesics that approaches a
null plane at infinity. Its form can be given explicitly in terms of elliptic
functions, and we use it to analyze and illustrate the time-evolution of the
horizon along the merger. We identify features such as the line of caustics at
which light rays enter the horizon, and the critical point at which the
horizons touch. We also compute several quantities that characterize these
aspects of the merger.


title: LevelMerge: Collaborative Game Level Editing by Merging Labeled Graphs

abstract:
  Game level editing is the process of constructing a full game level starting
from 3D asset libraries, e.g. 3d models, textures, shaders, scripts. In level
editing, designers define the look and behavior of the whole level by placing
objects, assigning materials and lighting parameters, setting animations and
physics properties and customizing the objects AI and behavior by editing
scripts. The heterogeneity of the task usually translates to a workflow where a
team of people, experts on separate aspects, cooperate to edit the game level,
often working on the same objects (e.g.: a programmer working on the AI of a
character, while an artist works on its 3D model or its materials). Today this
collaboration is established by using version control systems designed for text
documents, such as Git, to manage different versions and share them amongst
users. The merge algorithms used in these systems though does not perform well
in our case since it does not respect the relations between game objects
necessary to maintain the semantic of the game level behavior and look. This is
a known problem and commercial systems for game level merging exists, e.g.
PlasticSCM, but these are only slightly more robust than text-based ones. This
causes designers to often merge scenes manually, essentially reapplying others
edits in the game level editor.


title: A non-uniform distribution of the nearest brown dwarfs

abstract:
  The census of solar neighbours is still complemented by new discoveries,
mainly of very low-mass, faint dwarfs, close to or within the substellar
domain. These discoveries contribute to a better understanding of the field
population; its origin in terms of Galactic dynamics and (sub)stellar formation
and evolution. Also, the nearest stars and brown dwarfs at any given age allow
the most precise direct characterization, including the search for planetary
companions. We aim to further assess the substellar census on the Galactic
plane. We projected the 136 stars and 26 brown dwarfs known at <6.5 pc on the
Galactic plane and evaluated their distributions. Stars present a uniform- and
brown dwarfs a non-uniform distribution, with 21 objects behind the Sun and
only five ahead relative to the direction of rotation of the Galaxy. This
substellar configuration has a probability of 0.098$^{+10.878}_{-0.098}$%
relative to uniformity. The helio- and geocentric nature of the distribution
suggests it might result in part from an observational bias, which if
compensated for by future discoveries, might increase the brown-dwarf-to-star
ratio, shifting it closer to values found in some star forming regions.


title:
Hot gas and magnetic arms of NGC 6946: indications for reconnection
  heating?

abstract:
  The grand-design face-on spiral galaxy NGC6946 is remarkable because of its
high star formation activity, the massive northern spiral arm, and the magnetic
arms, which are observed in polarized radio synchrotron emission and are
located between the optical arms and possibly are magnetic reconnection
regions. X-ray observations of NGC6946 performed with XMM-Newton were used to
study the emission from X-ray point sources and diffuse hot gas, including the
magnetic arms and the halo. Spectral fitting of the diffuse X-ray emission
allowed us to derive temperatures of the hot gas. With assumptions about the
emission volume, this allowed us to estimate gas densities, masses, and cooling
times. To explain the X-ray emission from the spiral arms of NGC6946
two-temperature plasma models are needed to account for the disk and halo
emission. The interarm regions show only one thermal component. We observe that
the temperature of the hot gas in and above the magnetic arm regions increases
slightly when compared to the average temperatures in the areas in and above
the spiral arms. For the southwestern part of the disk, which is depolarized in
the radio range by Faraday rotation, we find more efficient mixing of disk and
halo gas. We propose magnetic reconnection in the magnetic arm regions of
NGC6946 as the possible cause of the additional heating of the gas and ordering
of the magnetic fields. In the southwestern part of the galactic disk we
observed indications of a possible faster outflow of the hot gas. A very hot
gas within the MF16 nebula possibly suggests shock heating by a supernova
explosion.


title: Quantum Monte Carlo simulation with a black hole

abstract:
  We perform quantum Monte Carlo simulations in the background of a classical
black hole. The lattice discretized path integral is numerically calculated in
the Schwarzschild metric and in its approximated metric. We study spontaneous
symmetry breaking of a real scalar field theory. We observe inhomogeneous
symmetry breaking induced by inhomogeneous gravitational field.


title:
Learning Supervised PageRank with Gradient-Based and Gradient-Free
  Optimization Methods

abstract:
  In this paper, we consider a non-convex loss-minimization problem of learning
Supervised PageRank models, which can account for some properties not
considered by classical approaches such as the classical PageRank model. We
propose gradient-based and random gradient-free methods to solve this problem.
Our algorithms are based on the concept of an inexact oracle and unlike the
state state-of-the-art gradient-based method we manage to provide theoretically
the convergence rate guarantees for both of them. In particular, under the
assumption of local convexity of the loss function, our random gradient-free
algorithm guarantees decrease of the loss function value expectation. At the
same time, we theoretically justify that without convexity assumption for the
loss function our gradient-based algorithm allows to find a point where the
stationary condition is fulfilled with a given accuracy. For both proposed
optimization algorithms, we find the settings of hyperparameters which give the
lowest complexity (i.e., the number of arithmetic operations needed to achieve
the given accuracy of the solution of the loss-minimization problem). The
resulting estimates of the complexity are also provided. Finally, we apply
proposed optimization algorithms to the web page ranking problem and compare
proposed and state-of-the-art algorithms in terms of the considered loss
function.


title: Higgs mass and unified gauge coupling in the NMSSM with Vector Matter

abstract:
  We consider the NMSSM extended to include one vector-like family of quarks
and leptons. If (some of) these vector-like matter particles, as the Higgs
doublets, have Yukawa couplings to the singlet S that exceed unity at about the
same scale $\Lambda \lesssim 10^3$ TeV, this gives the order 40 % enhancement
of the tree level Higgs boson mass required in the MSSM to reach 125 GeV. It is
conceivable that the Yukawa couplings to the singlet S, although naively
blowing up close to $\Lambda$, will not spoil gauge coupling unification. In
such a case the unified coupling $\alpha_X$ could be interestingly led to a
value not far from unity, thus providing a possible explanation for the number
of generations. The characteristic signal is an enhanced resonant production of
neutral spin zero particles at LHC, that could even explain the putative
diphoton resonance hinted by the recent LHC data at 750 GeV.


title: Four Loop Scattering in the Nambu-Goto Theory

abstract:
  We initiate the study of multiloop scattering amplitudes in the Nambu-Goto
theory on the worldsheet of a non-critical string. We start with a brute force
calculation of two loop four particle scattering. Somewhat surprisingly, even
though non-trivial UV counterterms are present at this order, on-shell
amplitudes remain polynomial in the momenta of colliding particles. We show
that this can be understood as a consequence of existence of certain close by
(semi)integrable models. Furthermore, these arguments can be extended to obtain
the answer for three and four loop scattering, bypassing the brute force
calculation. The resulting amplitudes develop non-polynomial (logarithmic)
dependence on the momenta starting at three loops.


title: DAMEWARE - Data Mining & Exploration Web Application Resource

abstract:
  Astronomy is undergoing through a methodological revolution triggered by an
unprecedented wealth of complex and accurate data. DAMEWARE (DAta Mining &
Exploration Web Application and REsource) is a general purpose, Web-based,
Virtual Observatory compliant, distributed data mining framework specialized in
massive data sets exploration with machine learning methods. We present the
DAMEWARE (DAta Mining & Exploration Web Application REsource) which allows the
scientific community to perform data mining and exploratory experiments on
massive data sets, by using a simple web browser. DAMEWARE offers several tools
which can be seen as working environments where to choose data analysis
functionalities such as clustering, classification, regression, feature
extraction etc., together with models and algorithms.


title:
Insights from a minimal model of dislocation-assisted rafting in single
  crystal Nickel-based superalloys

abstract:
  Nickel-based superalloys play a major role in many technologically relevant
high temperature applications. Understanding and predicting the evolution of
the phase microstructure during high temperature creep together with the
evolution of the dislocation microstructure is a challenge that up to date has
not yet been fully accomplished. Our two-dimensional coupled
phase-field/continuum dislocation dynamics model explains microstructural
mechanisms which are important during the early stage of rafting in a single
crystal system. It shows how $\gamma/\gamma'$ phases and dislocations interact
giving rise to realistic creep behavior; no phenomenological fit parameters are
required.


title:
Integrals of products of Hurwitz zeta functions and the Casimir effect
  in $\phi^4$ field theories

abstract:
  We evaluate two integrals over $x\in [0,1]$ involving products of the
function $\zeta_1(a,x)\equiv \zeta(a,x)-x^{-a}$ for $\Re (a)>1$, where
$\zeta(a,x)$ is the Hurwitz zeta function. The evaluation of these integrals
for the particular case of integer $a\geq 2$ is also presented. As an
application we calculate the $O(g)$ weak-coupling expansion coefficient
$c_{1}(\varepsilon)$ of the Casimir energy for a film with Dirichlet-Dirichlet
boundary conditions, first stated by Symanzik [Schr\"odinger representation and
Casimir effect in renormalizable quantum field theory, Nucl. Phys. B 190 (1981)
1-44] in the framework of $g\phi^4_{4-\varepsilon}$ theory.


title:
On the formation of molecules and solid-state compounds from the AGB to
  the PN phases

abstract:
  During the asymptoyic giant branch (AGB) phase, different elements are
dredge-up to the stellar surface depending on progenitor mass and metallicity.
When the mass loss increases at the end of the AGB, a circumstellar dust shell
is formed, where different (C-rich or O-rich) molecules and solid-state
compounds are formed. These are further processed in the transition phase
between AGB stars and planetary nebulae (PNe) to create more complex organic
molecules and inorganic solid-state compounds (e.g., polycyclic aromatic
hydrocarbons, fullerenes, and graphene precursors in C-rich environments and
oxides and crystalline silicates in O-rich ones). We present an observational
review of the different molecules and solid-state materials that are formed
from the AGB to the PN phases. We focus on the formation routes of complex
fullerene (and fullerene-based) molecules as well as on the level of dust
processing depending on metallicity.

categories: astro-ph.SR astro-ph.GA physics.chem-ph physics.space-ph


title:
Analysis on a Nambu--Jona-Lasinio Model of Dynamical Supersymmetry
  Breaking

abstract:
  This is a report on our newly proposed model of dynamical supersymmetry
breaking with some details of the analysis involved. The model in the simplest
version has only a chiral superfield (multiplet), with a strong four-superfield
interaction in the K\"ahler potential that induces a real two-superfield
composite with vacuum condensate. The latter has supersymmetry breaking parts,
which we show to bear nontrivial solution following basically a standard
nonperturbative analysis for a Nambu--Jona-Lasinio type model on a superfield
setting. The real composite superfield has a spin one component but is
otherwise quite unconventional. We discuss also the parallel analysis for the
effective theory with the composite. Plausible vacuum solutions are illustrated
and analyzed. The supersymmetry breaking solutions have generated soft mass(es)
for the scalar avoiding the vanishing supertrace condition for the
squared-masses of the superfield components. We also present some analysis of
the resulted low energy effective theory with components of the composite
become dynamical. The determinant of the fermionic modes is shown to be zero
illustrating the presence of the expected Goldstino. The model gives the
possibility of constructing a supersymmetric standard model with all
(super)symmetry breaking masses generated dynamically and directly without the
necessity of complicated hidden or mediating sectors.


title:
Identification of structural relaxation in the dielectric response of
  water

abstract:
  One century ago pioneering dielectric results obtained for water and
n-alcohols triggered the advent of molecular rotation diffusion theory
considered by Debye to describe the primary dielectric absorption in these
liquids. Comparing dielectric, viscoelastic, and light scattering results we
unambiguously demonstrate that the structural relaxation appears only as a
high-frequency shoulder in the dielectric spectra of water. In contrast, the
main dielectric peak is related to a supramolecular structure, analogous to the
Debye-like peak observed in mono-alcohols.


title: Single-pixel 3D imaging with time-based depth resolution

abstract:
  Time-of-flight three dimensional imaging is an important tool for many
applications, such as object recognition and remote sensing. Unlike
conventional imaging approach using pixelated detector array, single-pixel
imaging based on projected patterns, such as Hadamard patterns, utilises an
alternative strategy to acquire information with sampling basis. Here we show a
modified single-pixel camera using a pulsed illumination source and a
high-speed photodiode, capable of reconstructing 128x128 pixel resolution 3D
scenes to an accuracy of ~3 mm at a range of ~5 m. Furthermore, we demonstrate
continuous real-time 3D video with a frame-rate up to 12 Hz. The simplicity of
the system hardware could enable low-cost 3D imaging devices for precision
ranging at wavelengths beyond the visible spectrum.


title: Shape Driven Solid--Solid Transitions in Colloids

abstract:
  Despite the fundamental importance of solid--solid transitions for
metallurgy, ceramics, earth science, reconfigurable materials, and colloidal
matter, the details of how materials transform between two solid structures are
poorly understood. We introduce a class of {simple} model systems in which the
direct control of local order, via colloid shape change, induces solid--solid
phase transitions, and characterize how the transitions happen
thermodynamically. We find that within a single shape family there are
solid--solid transitions that can occur with or without a thermal activation
barrier. Our results provide new means for the study of solid--solid phase
transitions, and have implications for designing reconfigurable materials.


title:
Superradiant Emission of Ultra-Bright Photon Pairs in Doppler-Broadened
  Atomic Ensemble

abstract:
  With a recent rising interest of single photon superradiance due to its
potential usefulness for efficient collection of single photon from an atomic
ensemble, bright and narrow photon pair source is a key component in
realization of quantum communication and quantum computer based on coherent
interaction between light and atomic ensemble. We report the superradiant
emission of ultra-bright photon pairs with a coincidence counting rate per
input power of 64,600 cps/mW via spontaneous four-wave mixing in a thermal
vapour cell. The photon-pair generation rate is enhanced by the contribution of
two-photon coherence of almost atomic velocity groups in the Doppler-broadened
ladder-type atomic system. The quadratic proportionality of the probability of
detecting a heralded single photon as a function of the optical depth clarifies
that the ultra-brightness results from the superradiance. In addition, a single
photon superradiant beating at a high optical depth of the atomic ensemble is
observed for the first time.


title:
The advantages of using a Lucky Imaging camera for observations of
  microlensing events

abstract:
  In this work, we study the advantages of using a Lucky Imaging camera for the
observations of potential planetary microlensing events. Our aim is to reduce
the blending effect and enhance exoplanet signals in binary lensing systems
composed of an exoplanet and the corresponding parent star. We simulate
planetary microlensing light curves based on present microlensing surveys and
follow-up telescopes where one of them is equipped with a Lucky imaging camera.
This camera is used at the Danish $1.54$-m follow-up telescope. Using a
specific observational strategy, For an Earth-mass planet in the resonance
regime, where the detection probability in crowded-fields is smaller, lucky
imaging observations improve the detection efficiency which reaches 2 per cent.
Given the difficulty of detecting the signal of an Earth-mass planet in
crowded-field imaging even in the resonance regime with conventional cameras,
we show that Lucky Imaging can substantially improve the detection efficiency.


title:
Search for VHE gamma-ray emission from Geminga pulsar and nebula with
  the MAGIC telescopes

abstract:
  The Geminga pulsar, one of the brighest gamma-ray sources, is a promising
candidate for emission of very-high-energy (VHE > 100 GeV) pulsed gamma rays.
Also, detection of a large nebula have been claimed by water Cherenkov
instruments. We performed deep observations of Geminga with the MAGIC
telescopes, yielding 63 hours of good-quality data, and searched for emission
from the pulsar and pulsar wind nebula. We did not find any significant
detection, and derived 95% confidence level upper limits. The resulting upper
limits of 5.3 x 10^{-13} TeV cm^{-2} s^{-1} for the Geminga pulsar and 3.5 x
10^{-12} TeV cm^{-2} s^{-1} for the surrounding nebula at 50 GeV are the most
constraining ones obtained so far at VHE. To complement the VHE observations,
we also analyzed 5 years of Fermi-LAT data from Geminga, finding that the
sub-exponential cut-off is preferred over the exponential cut-off that has been
typically used in the literature. We also find that, above 10 GeV, the
gamma-ray spectra from Geminga can be described with a power law with index
softer than 5. The extrapolation of the power-law Fermi-LAT pulsed spectra to
VHE goes well below the MAGIC upper limits, indicating that the detection of
pulsed emission from Geminga with the current generation of Cherenkov
telescopes is very difficult.


title: Quantization for a probability distribution generated by an infinite IFS

abstract:
  Quantization for probability distributions concerns the best approximation of
a $d$-dimensional probability distribution $P$ by a discrete probability with a
given number $n$ of supporting points. In this paper, we have considered a
probability measure generated by an infinite iterated function system
associated with a probability vector on $\mathbb R$. For such a probability
measure $P$, an induction formula to determine the optimal sets of $n$-means
and the $n$th quantization error for every natural number $n$ is given. In
addition, using the induction formula we give some results and observations
about the optimal sets of $n$-means for all $n\geq 2$.


title: Ringed accretion disks: instabilities

abstract:
  We analyze the possibility that several instability points may be formed, due
to the Paczy\'nski mechanism of violation of mechanical equilibrium, in the
orbiting matter around a supermassive Kerr black hole. We consider recently
proposed model of ringed accretion disk, made up by several tori (rings) which
can be corotating or counterrotating relative to the Kerr attractor due to the
history of the accretion process. Each torus is governed by the general
relativistic hydrodynamic Boyer condition of equilibrium configurations of
rotating perfect fluids. We prove that the number of the instability points is
generally limited and depends on the dimensionless spin of the rotating
attractor.


title: Totally decomposable symplectic and unitary involutions

abstract:
  We study totally decomposable symplectic and unitary involutions on central
simple algebras of index 2 and on split central simple algebras respectively.
We show that for every field extension, these involutions are either
anisotropic or hyperbolic after extending scalars, and that the converse holds
if the algebras are of 2-power degree. These results are new in characteristic
2, otherwise were shown in [3] and [6] respectively.


title:
Frequency-Domain Chromatic Dispersion Equalization Using Overlap-Add
  Methods in Coherent Optical System

abstract:
  The frequency domain equalizers (FDEs) employing two types of overlap-add
zero-padding (OLA-ZP) methods are applied to compensate the chromatic
dispersion in a 112-Gbit/s non-return-to-zero polarization division multiplexed
quadrature phase shift keying (NRZ-PDM-QPSK) coherent optical transmission
system. Simulation results demonstrate that the OLA-ZP methods can achieve the
same acceptable performance as the overlap-save method. The required minimum
overlap (or zero-padding) in the FDE is derived, and the optimum fast Fourier
transform length to minimize the computational complexity is also analyzed.


title: Construction of a surface pencil with a common special surface curve

abstract:
  In this study, we introduce a new type of surface curves called D-type curve.
This curve is defined by the property that the unit Darboux vector W0 of a
space curve r(s) and unit surface normal n along the curve r(s) satisfy the
condition <n,W0>=constant. We point out that a D-type curve is a geodesic curve
or an asymptotic curve in some special cases. Then, by using the Frenet vectors
and parametric representation of a surface pencil as a linear combination of
the Frenet vectors, we investigate necessary and sufficient condition for a
curve to be a D-type curve on a surface pencil. Moreover, we introduce some
corollaries by considering D-type curve as a helix, a Salkowski curve or a
planar curve. Finally, we give some examples for obtained results and plot the
surfaces by using Mapple.


title:
Puzzling properties of the historical growth rate of income per capita
  explained

abstract:
  Galor discovered many mysteries of the growth process. He lists them in his
Unified Growth Theory and wonders how they can be explained. Close inspection
of his mysteries reveals that they are of his own creation. They do not exist.
He created them by his habitually distorted presentation of data. One of his
self-created mysteries is the mystery of the alleged sudden spurt in the growth
rate of income per capita. This sudden spurt never happened. In order to
understand the growth rate of income per capita, its mathematical properties
are now explored and explained. The explanation is illustrated using the
historical world economic growth. Galor also wonders about the sudden spurt in
the growth rate of population. We show that this sudden spurt was also created
by the distorted presentation of data. The mechanism of the historical economic
growth and of the growth of human population is yet to be explained but it
would be unproductive to try to explain the non-existing and self-created
mysteries of the growth process described in the scientifically unacceptable
Unified Growth Theory. However, the problem is much deeper than just the
examination of this theory. Demographic Growth Theory is based on the incorrect
but deeply entrenched postulates developed by accretion over many years and now
generally accepted in the economic and demographic research, postulates
revolving around the concept of Malthusian stagnation and around a transition
from stagnation to growth. The study presented here and earlier similar
publications show that these postulates need to be replaced by interpretations
based on the mathematical analysis of data and on the correct understanding of
hyperbolic distributions.


title: Rational curves in CICY's in products of two projective spaces

abstract:
  Let $X$ be the product of two projective spaces and consider the general CICY
threefold $Y$ in $X$ with configuration matrix $A$. We prove the finiteness
part of the analogue of the Clemens' conjecture for such a CICY in low
bidegrees. More precisely, we prove that the number of smooth rational curves
on $Y$ with low bidegree and with nondegenerate birational projection is at
most finite (even in cases in which positive dimensional families of degenerate
rational curves are known).


title:
Mandelbrot's 1/f fractional renewal models of 1963-67: The non-ergodic
  missing link between change points and long range dependence

abstract:
  The problem of 1/f noise has been with us for about a century. Because it is
so often framed in Fourier spectral language, the most famous solutions have
tended to be the stationary long range dependent (LRD) models such as
Mandelbrot's fractional Gaussian noise. In view of the increasing importance to
physics of non-ergodic fractional renewal models, I present preliminary results
of my research into the history of Mandelbrot's very little known work in that
area from 1963-67. I speculate about how the lack of awareness of this work in
the physics and statistics communities may have affected the development of
complexity science, and I discuss the differences between the Hurst effect, 1/f
noise and LRD, concepts which are often treated as equivalent.