title:
Geometric field theory and weak Euler-Lagrange equation for classical
  relativistic particle-field systems

abstract:
  A manifestly covariant, or geometric, field theory for relativistic classical
particle-field system is developed. The connection between space-time symmetry
and energy-momentum conservation laws for the system is established
geometrically without splitting the space and time coordinates, i.e.,
space-time is treated as one identity without choosing a coordinate system. To
achieve this goal, we need to overcome two difficulties. The first difficulty
arises from the fact that particles and field reside on different manifold. As
a result, the geometric Lagrangian density of the system is a function of the
4-potential of electromagnetic fields and also a functional of particles'
world-lines. The other difficulty associated with the geometric setting is due
to the mass-shell condition. The standard Euler-Lagrange (EL) equation for a
particle is generalized into the geometric EL equation when the mass-shell
condition is imposed. For the particle-field system, the geometric EL equation
is further generalized into a weak geometric EL equation for particles. With
the EL equation for field and the geometric weak EL equation for particles,
symmetries and conservation laws can be established geometrically. A geometric
expression for the energy-momentum tensor for particles is derived for the
first time, which recovers the non-geometric form in the existing literature
for a chosen coordinate system.


title: Interference between the modes of an all-dielectric meta-atom

abstract:
  The modes of silicon meta-atoms are investigated, motivated by their use as
building blocks of Huygens' metasurfaces. A model based on these modes is
presented, giving a clear physical explanation of all features in the
extinction spectrum. Counter-intuitively, this can show negative contributions
to extinction, which are shown to arise from the interference between
non-orthogonal modes. The direct and interference contributions to extinction
are determined, showing that conservation of energy is preserved. The Huygens'
condition of matched electric and magnetic dipole moments leads to strong
forward scattering and suppressed back scattering. It is shown that higher
order modes with appropriate symmetry generalise this condition, leading to
multiple bands of directional scattering. The presented results are obtained
using a robust approach to find the modes of nano-photonic scatterers, commonly
referred to as quasi-normal modes. By utilising an integral formulation of
Maxwell's equations, this work avoids the problem of normalising diverging
far-fields, which other approaches require. The model and presented results are
implemented in open-source code.


title: Dynamics of the tri-nuclear system at spontaneous fission of $^{252}$Cf

abstract:
  To describe of dynamics of ternary fission of $^{252}$Cf an equation of
motion of the tri-nuclear system is calculated. The fission of the
$^{70}$Ni+$^{50}$Ca+$^{132}$Sn channel was chosen as one of the more probable
channels of true ternary fission of $^{252}$Cf. The collinearity of ternary
fission has been checked by analyzing results of the equation of motion. The
results show that if initially all nuclei are placed collinearly (potential
energy of this position is the smallest) and the component of the middle
fragment's initial velocity which is perpendicular to this line, is zero then
ternary fission is collinear, otherwise the non collinear ternary fission takes
place.


title:
D2D-U: Device-to-Device Communications in Unlicensed Bands for 5G and
  Beyond

abstract:
  Device-to-Device (D2D) communication, which enables direct communication
between nearby mobile devices, is an attractive add-on component to improve
spectrum efficiency and user experience by reusing licensed cellular spectrum
in 5G system. In this paper, we propose to enable D2D communication in
unlicensed spectrum (D2D-U) as an underlay of the uplink LTE network for
further booming the network capacity. A sensing-based protocol is designed to
support the unlicensed channel access for both LTE and D2D users. We further
investigate the subchannel allocation problem to maximize the sum rate of LTE
and D2D users while taking into account their interference to the existing
Wi-Fi systems. Specifically, we formulate the subchannel allocation as a
many-to-many matching problem with externalities, and develop an iterative
user-subchannel swap algorithm. Analytical and simulation results show that the
proposed D2D-U scheme can significantly improve the system sum-rate.


title: Improved bounds for sparse recovery from subsampled random convolutions

abstract:
  We study the recovery of sparse vectors from subsampled random convolutions
via $\ell_1$-minimization. We consider the setup in which both the subsampling
locations as well as the generating vector are chosen at random. For a
subgaussian generator with independent entries, we improve previously known
estimates: if the sparsity $s$ is small enough, i.e., $s \lesssim
\sqrt{n/\log(n)}$, we show that $m \gtrsim s \log(en/s)$ measurements are
sufficient to recover $s$-sparse vectors in dimension $n$ with high
probability, matching the well-known condition for recovery from standard
Gaussian measurements. If $s$ is larger, then essentially $m \geq s \log^2(s)
\log(\log(s)) \log(n)$ measurements are sufficient, again improving over
previous estimates. Our results are shown via the so-called robust null space
property which is weaker than the standard restricted isometry property. Our
method of proof involves a novel combination of small ball estimates with
chaining techniques {which should be of independent interest.


title:
Real meromorphic differentials: a language for the meron configurations
  in planar nanomagnets

abstract:
  In this paper we use the language of real meromorphic differentials from the
theory of Klein surfaces to describe the metastable states of multiply
connected planar ferromagnetic nanoelements which minimize the exchange energy
and have no side magnetic charges. Those solutions still have enough internal
degrees of freedom which may serve as the Ritz parameters for minimization of
further relevant energy terms or as the dynamical variables for the adiabatic
approach. The nontrivial topology of the magnet itself brings us to several
effects first described for the annulus and observed in the experiment. We
explain the topological constraints on the numbers of vortexes and antivortexes
in the magnet, as well as the algebraic constraints on their positions which
stem from the Abel's theorem. The use of multivalued Prym differentials bring
us to new meron configurations which were not considered in the seminal work of
D.J.Gross.

categories: cond-mat.mes-hall math-ph math.CV math.MP


title:
Some extensions of linear approximation and prediction problems for
  stationary processes

abstract:
  Let $(B(t))_{t\in \Theta}$ with $\Theta={\mathbb Z}$ or $\Theta={\mathbb R}$
be a wide sense stationary process with discrete or continuous time. The
classical linear prediction problem consists of finding an element in
$\overline{span}\{B(s),s\le t\}$ providing the best possible mean square
approximation to the variable $B(\tau)$ with $\tau>t$.
  In this article we investigate this and some other similar problems where, in
addition to prediction quality, optimization takes into account other features
of the objects we search for. One of the most motivating examples of this kind
is an approximation of a stationary process $B$ by a stationary differentiable
process $X$ taking into account the kinetic energy that $X$ spends in its
approximation efforts.


title: A Three-loop Neutrino Mass Model with a Colored Triplet Scalar

abstract:
  We study a variation of the Krauss-Nasri-Trodden (KNT) model with a colored
triplet scalar field and a colored singlet scalar field, in which we discuss
the anomaly coming from $b\to s\mu\bar\mu$, fitting to the muon anomalous
magnetic moment and the relic density of the Majorana-type dark matter
candidate, as well as satisfying various constraints such as lepton-flavor
violations and flavor-changing neutral currents. Also, we discuss the direct
constraints from the collider searches and the possibilities of detecting the
new fields at the LHC.


title:
H\"older regularity for the gradient of the inhomogeneous parabolic
  normalized $p$-Laplacian

abstract:
  In this paper we study an evolution equation involving the normalized
$p$-Laplacian and a bounded continuous source term. The normalized
$p$-Laplacian is in non divergence form and arises for example from stochastic
tug-of-war games with noise. We prove local $C^{\alpha, \frac{\alpha}{2}}$
regularity for the spatial gradient of the viscosity solutions. The proof is
based on an improvement of flatness and proceeds by iteration.


title:
Coupled and decoupled impedance models compared in power electronics
  systems

abstract:
  This paper provides a comparative analysis of impedance models for power
electronic converters and systems for the purpose of stability investigations.
Such models can be divided into either decoupled models or matrix models. A
decoupled impedance model is highly appealing since the
Single-Input-Single-Output (SISO) structure makes the analysis and result
interpretation very simple. On the other hand, matrix impedance models are more
accurate, and in some cases necessary. Previous works have applied various
approximations to obtain decoupled models, and both the dq- and sequence
domains have been used. This paper introduces the terms decoupled and
semi-decoupled impedance models in order to have a clear classification of the
available approximations.
  The accuracy of 4 decoupled impedance models are discussed based on the
concept of Mirror Frequency Coupling (MFC). By definition the decoupled models
based on sequence domain impedances will be exact for systems without MFC. In
the general case, they are expected to be more accurate than the decoupled
dq-impedance models. The paper defines a norm $\epsilon$ to measure the degree
of coupling in the impedance matrices. This norm equals the error in the
eigenvalue loci between the matrix and semi-decoupled models. This can also be
viewed as the error in the semi-decoupled Nyquist plot.
  An example case study consisting of a grid-connected VSC with current
controller and PLL is used to compare the different methods. It is found that
decoupled and semi-decoupled models in the dq-domain are only applicable in
grids with very low X/R-ratio. Furthermore, it is concluded that the decoupled
model in the sequence domain gives close to equal results as the semi-decoupled
model.


title:
Cached Long Short-Term Memory Neural Networks for Document-Level
  Sentiment Classification

abstract:
  Recently, neural networks have achieved great success on sentiment
classification due to their ability to alleviate feature engineering. However,
one of the remaining challenges is to model long texts in document-level
sentiment classification under a recurrent architecture because of the
deficiency of the memory unit. To address this problem, we present a Cached
Long Short-Term Memory neural networks (CLSTM) to capture the overall semantic
information in long texts. CLSTM introduces a cache mechanism, which divides
memory into several groups with different forgetting rates and thus enables the
network to keep sentiment information better within a recurrent unit. The
proposed CLSTM outperforms the state-of-the-art models on three publicly
available document-level sentiment analysis datasets.


title:
Transition to kinetic turbulence at proton scales driven by
  large-amplitude Kinetic Alfv\`en fluctuations

abstract:
  Space plasmas are dominated by the presence of large-amplitude waves,
large-scale inhomogeneities, kinetic effects and turbulence. Beside the
homogeneous turbulence, generation of small scale fluctuations can take place
also in other realistic configurations, namely, when perturbations superpose to
an inhomogeneous background magnetic field. When an Alfv\'en wave propagates in
a medium where the Alfv\'en speed varies in a direction transverse to the mean
field, it undergoes phase-mixing, which progressively bends wavefronts,
generating small scales in the transverse direction. As soon as transverse
scales get of the order of the proton inertial length $d_p$, kinetic Alfv\'en
waves (KAWs) are naturally generated. KAWs belong to the branch of Alfv\'en
waves and propagate nearly perpendicular to the ambient magnetic field, at
scales close to $d_p$. Many numerical, observational and theoretical works have
suggested that these fluctuations may play a determinant role in the
development of the solar-wind turbulent cascade. In the present paper, the
generation of large amplitude KAW fluctuations in inhomogeneous background and
their effect on the protons have been investigated by means of hybrid
Vlasov-Maxwell direct numerical simulations. Imposing a pressure balanced
magnetic shear, the kinetic dynamics of protons has been investigated by
varying both the magnetic configuration and the amplitude of the initial
perturbations. Of interest here is the transition from quasi-linear to
turbulent regimes, focusing, in particular, on the development of important
non-Maxwellian features in the proton distribution function driven by KAW
fluctuations.


title:
Strong decays of $D_{3}^{\ast}(2760)$, $D_{s3}^{\ast}(2860)$,
  $B_{3}^{\ast}$, and $B_{s3}^{\ast}$

abstract:
  In this paper, we study the OZI-allowed two-body strong decays of $3^-$
heavy-light mesons. Experimentally the charmed $D_{3}^{\ast}(2760)$ and the
charm-strange $D_{s3}^{\ast}(2860)$ states with these quantum numbers have been
discovered. For the bottomed $B(5970)$ state, which was found by the CDF
Collaboration recently, its quantum number has not been decided yet and we
assume its a $3^-$ meson in this paper. The theoretical prediction for the
strong decays of bottom-strange state $B_{s3}^\ast$ is also given. The
relativistic wave functions of $3^-$ heavy mesons are constructed and their
numerical values are obtained by solving the corresponding Bethe-Salpeter
equation with instantaneous approximation. The transition matrix is calculated
by using the PCAC and low energy theorem, following which, the decay widths are
obtained. For $D_{3}^\ast(2760)$ and $D_{s3}^\ast(2860)$, the total strong
decay widths are 72.6 MeV and 47.6 MeV, respectively. For $B_3^\ast$ with
$M=5978$ MeV and $B_{s3}^\ast$ with $M=6178$ MeV, their strong decay widths are
22.9 MeV and 40.8 MeV, respectively.


title: Generation of Highly Inclined Trans-Neptunian Objects by Planet Nine

abstract:
  The trans-Neptunian region of the solar system exhibits an intricate
dynamical structure, much of which can be explained by an instability-driven
orbital history of the giant planets. However, the origins of a highly
inclined, and in certain cases retrograde, population of trans-Neptunian
objects remain elusive within the framework of this evolutionary picture. In
this work, we show that the existence of a distant, Neptune-like planet that
resides on an eccentric and mildly inclined orbit fully accounts for the
anomalous component the trans-Neptunian orbital distribution. Adopting the same
parameters for Planet Nine as those previously invoked to explain the
clustering of distant Kuiper belt orbits in physical space, we carry out a
series of numerical experiments which elucidate the physical process though
which highly inclined Kuiper belt objects with semi-major axes smaller than 100
AU are generated. The identified dynamical pathway demonstrates that enigmatic
members of the Kuiper belt such as Drac and Niku are derived from the extended
scattered disk of the solar system.


title: An Iwahori-Matsumoto presentation of affine Yokonuma-Hecke algebras

abstract:
  We first present an Iwahori-Matsumoto presentation of affine Yokonuma-Hecke
algebras $\widehat{Y}_{r,n}(q)$ to give a new proof of the fact, which was
previously proved by Chlouveraki and S\'echerre, that $\widehat{Y}_{r,n}(q)$ is
a particular case of the pro-$p$-Iwahori-Hecke algebras defined by Vign\'eras,
meanwhile, we give one application. Using the new presentation, we then give a
third presentation of $\widehat{Y}_{r,n}(q),$ from which we immediately get an
unexpected result, that is, the extended affine Hecke algebra of type $A$ is a
subalgebra of the affine Yokonuma-Hecke algebra.


title:
Analysis of Discontinuous Galerkin Methods using Mesh-Dependent Norms
  and Applications to Problems with Rough Data

abstract:
  We prove the inf-sup stability of a discontinuous Galerkin scheme for second
order elliptic operators in (unbalanced) mesh-dependent norms for quasi-uniform
meshes for all spatial dimensions. This results in a priori error bounds in
these norms. As an application we examine a problem with rough source term
where the solution can not be characterised as a weak solution and show
quasi-optimal error control.


title: Conic bundles with nontrivial unramified Brauer group over threefolds

abstract:
  We derive a formula for the unramified Brauer group of a general class of
rationally connected fourfolds birational to conic bundles over smooth
threefolds. We produce new examples of conic bundles over P^3 where this
formula applies and which have nontrivial unramified Brauer group. The
construction uses the theory of contact surfaces and, at least implicitly,
matrix factorizations and symmetric arithmetic Cohen--Macaulay sheaves, as well
as the geometry of special arrangements of rational curves in P^2. We also
prove the existence of universally CH_0-trivial resolutions for the general
class of conic bundle fourfolds we consider. Using the degeneration method, we
thus produce new families of rationally connected fourfolds whose very general
member is not stably rational.


title:
Pressure effects on the unconventional superconductivity of the
  noncentrosymmetric LaNiC2

abstract:
  The unconventional superconductivity in the noncentrosymmetric LaNiC$_2$, and
its evolution with pressure, is analyzed basing on the {\it ab initio}
computations and the full Eliashberg formalism. First principles calculations
of the electronic structure, phonons and the electron-phonon coupling are
reported in the pressure range 0-15 GPa. The thermodynamic properties of the
superconducting state were determined numerically solving the Eliashberg
equations. We found that already at $p=0$ GPa, the superconducting parameters
deviate from the BCS-type, and a large value of the Coulomb pseudopotential
$\mu^{\star}=0.22$ is required to get the critical temperature $T_c = 2.8$~K
consistent with experiment. If such $\mu^{\star}$ is used, the Eliashberg
formalism reproduces also the experimentally observed values of the
superconducting order parameter, the electronic specific heat jump at the
critical temperature, and the change of the London penetration depth with
temperature. This shows, that deviation of the above-mentioned parameters from
the BCS predictions do not prejudge on the triplet or multiple gap nature of
the superconductivity in this compound. Under the external pressure,
calculations predict continuous increase of the electron-phonon coupling
constant in the whole pressure range 0-15~GPa, consistent with the
experimentally observed increase in $T_c$ for the pressure range 0-4~GPa, but
inconsistent with the drop of $T_c$ above 4~GPa and the disappearance of the
superconductivity above 7~GPa, reported experimentally. The disappearance of
superconductivity may be accounted for by increasing the $\mu^{\star}$ to 0.36
at 7~GPa, which supports the hypothesis of the formation of a new high-pressure
electronic phase, which competes with the superconductivity.


title: Spatio-Temporal Attention Models for Grounded Video Captioning

abstract:
  Automatic video captioning is challenging due to the complex interactions in
dynamic real scenes. A comprehensive system would ultimately localize and track
the objects, actions and interactions present in a video and generate a
description that relies on temporal localization in order to ground the visual
concepts. However, most existing automatic video captioning systems map from
raw video data to high level textual description, bypassing localization and
recognition, thus discarding potentially valuable information for content
localization and generalization. In this work we present an automatic video
captioning model that combines spatio-temporal attention and image
classification by means of deep neural network structures based on long
short-term memory. The resulting system is demonstrated to produce
state-of-the-art results in the standard YouTube captioning benchmark while
also offering the advantage of localizing the visual concepts (subjects, verbs,
objects), with no grounding supervision, over space and time.


title: Homology pro stability for Tor-unital pro rings

abstract:
  Let $\{A_m\}$ be a pro system of associative commutative, not necessarily
unital, rings. Assume that the pro systems $\{\mathrm{Tor}^{\mathbb{Z}\ltimes
A_m}_i(\mathbb{Z},\mathbb{Z})\}_m$ vanish for all $i>0$. Then we prove that the
sequence \[
  \{H_l(\mathrm{GL}_n(A_m))\}_m \to \{H_l(\mathrm{GL}_{n+1}(A_m))\}_m \to
\{H_l(\mathrm{GL}_{n+2}(A_m)\}_m \to \cdots \] stabilizes up to pro
isomorphisms for $n$ large enough than $l$ and the stable range of $A_m$'s.


title:
An infinite presentation for the mapping class group of a non-orientable
  surface with boundary

abstract:
  We give an infinite presentation for the mapping class group of a
non-orientable surface with boundary components. The presentation is a
generalization of the presentation given by the second author [15].


title: Spectroscopic diagnostics for circumstellar disks of B[e] supergiants

abstract:
  B[e] supergiants (B[e]SGs) are emission-line objects, presumably in a
short-lived phase in the post-main sequence evolution of massive stars. Their
intense infrared excess emission indicates large amounts of warm circumstellar
dust, and the stars were longtime assumed to possess an aspherical wind
consisting of a classical line-driven wind in polar direction and a dense, slow
equatorial wind dubbed outflowing disk. The general properties obtained for
these disks are in line with this scenario, although current theories have
considerable difficulties reproducing the observed quantities. Therefore, more
sophisticated observational constraints are needed. These follow from combined
optical and infrared spectroscopic studies, which delivered the surprising
result that the circumstellar material of B[e]SGs is concentrated in multiple
rings revolving the stars on stable Keplerian orbits. Such a scenario requires
new ideas for the formation mechanism, in which pulsations might play an
important role.


title:
High resolution study of the yellow excitons in Cu$_2$O subject to an
  electric field

abstract:
  We have used high resolution transmission spectroscopy to study the exciton
level spectrum in Cu$_2$O subject to a longitudinal external electric field,
i.e., in the geometry where the transmitted light is propagating along the
field direction. Different experimental configurations given by the field
orientation relative to the crystal and the light polarization have been
explored. We focus on the range of small principal quantum numbers $n \leq 7$.
The number of exciton states belonging to a particular principal quantum number
increases with $n$, leading to an enhanced complexity of the spectra. Still, in
particular for $n = 3 \ldots 5$ a spectral separation of the different lines is
feasible and identification as well as assignment of the dominant state
character are possible. We find a strong dependence of the spectra on the
chosen light propagation direction and polarization configuration, reflecting
the inadequacy of the hydrogen model for describing the excitons. With
increasing the field excitonic states with different parity become mixed,
leading to optical activation of states that are dark in zero field. As
compared with atoms, due to the reduced Rydberg energy states with different
$n$ can be brought into resonance in the accessible electric field strength
range. When this occurs, we observe mostly crossing of levels within the
experimental accuracy showing that the electron and hole motion remains
regular. The observed features are well described by detailed calculations
accounting for the spin-orbit coupling, the cubic anisotropy effects, and the
symmetry-imposed optical selection rules.

categories: cond-mat.mtrl-sci cond-mat.mes-hall cond-mat.other quant-ph


title: Fermionic ghost imaging

abstract:
  Ghost imaging with thermal fermions is calculated based on two-particle
interference in Feynman's path integral theory. It is found that ghost imaging
with thermal fermions can be simulated by ghost imaging with thermal bosons and
classical particles. Photons in pseudothermal light are employed to
experimentally study fermionic ghost imaging. Ghost imaging with thermal bosons
and fermions is discussed based on the point-to-point (spot) correlation
between the object and image planes. The employed method offers an efficient
guidance for future ghost imaging with real thermal fermions, which may also be
generalized to study other second-order interference phenomena with fermions.


title:
Half-Chain Entanglement Entropy in the One-Dimensional Spinless Fermion
  Model

abstract:
  We calculate the half-chain entanglement entropy of the ground state in the
one-dimensional spinless fermion model. Considering a tiny corner of the
Hilbert space represented by matrix product states, we efficiently find the
ground state by the infinite time-evolving block decimation. The Schmidt
coefficients are used to determine the half-chain entanglement entropy. Using
the bond dimension scaling of the half-chain entanglement entropy, we find the
critical region, which is consistent with the previous results.


title: On the physical interpretation of non-metricity in Brans-Dicke gravity

abstract:
  Brans-Dicke theory is described by an action that allows the so called frame
transformation, which replaces the non-minimal coupling between the scalar
field and the curvature by a coupling between the scalar field and matter
fields. In this paper, we describe how the viewpoint that they are physically
equivalent has a geometrical counterpart in the framework of Weyl integrable
geometry. This way, Dicke's interpretation in terms of running units is a
physical manifestation of the non-metricity tensor.


title:
A Class of Semiparametric Tests of Treatment Effect Robust to Confounder
  Classical Measurement Error

abstract:
  When assessing the presence of an exposure causal effect on a given outcome,
it is well known that classical measurement error of the exposure can reduce
the power of a test of the null hypothesis in question, although its type I
error rate will generally remain at the nominal level. In contrast, classical
measurement error of a confounder can inflate the type I error rate of a test
of treatment effect. In this paper, we develop a large class of semiparametric
test statistics of an exposure causal effect, which are completely robust to
classical measurement error of a subset of confounders. A unique and appealing
feature of our proposed methods is that they require no external information
such as validation data or replicates of error-prone confounders. We present a
doubly-robust form of this test that requires only one of two models to be
correctly specified for the resulting test statistic to have correct type I
error rate. We demonstrate validity and power within our class of test
statistics through simulation studies. We apply the methods to a
multi-U.S.-city, time-series data set to test for an effect of temperature on
mortality while adjusting for atmospheric particulate matter with diameter of
2.5 micrometres or less (PM2.5), which is known to be measured with error.


title:
Cluster subalgebras and cotorsion pairs in Frobenius extriangulated
  categories

abstract:
  Nakaoka and Palu introduced the notion of extriangulated categories by
extracting the similarities between exact categories and triangulated
categories. In this paper, we study cotorsion pairs in a Frobenius
extriangulated category $\C$. Especially, for a $2$-Calabi-Yau extriangulated
category $\C$ with a cluster structure, we describe the cluster substructure in
the cotorsion pairs. For rooted cluster algebras arising from $\C$ with cluster
tilting objects, we give a one-to-one correspondence between cotorsion pairs in
$\C$ and certain pairs of their rooted cluster subalgebras which we call
complete pairs. Finally, we explain this correspondence by an example relating
to a Grassmannian cluster algebra.


title:
Spatial inhomogeneity and temporal dynamics of a 2D electron gas in
  interaction with a 2D adatom gas

abstract:
  Fundamental interest for 2D electron gas (2DEG) systems has been recently
renewed with the advent of 2D materials and their potential high-impact
applications in optoelectronics. Here, we investigate a 2DEG created by the
electron transfer from a Ag adatom gas deposited on a
Si(111)$\sqrt{3}\times\sqrt{3}$-Ag surface to an electronic surface state.
Using low-energy electron microscopy (LEEM), we measure the Ag adatom gas
concentration and the 2DEG-induced charge transfer. We demonstrate a linear
dependence of the surface work function change on the Ag adatom gas
concentration. A breakdown of the linear relationship is induced by the
occurrence of the Ag adatom gas superstructure identified as
Si(111)$\sqrt{21}\times\sqrt{21}$-Ag only observed below room temperature. We
evidence below room temperature a confinement of the 2DEG on atomic terraces
characterised by spatial inhomogeneities of the 2DEG-induced charge transfer
along with temporal fluctuations. These variations mirror the Ag adatom gas
concentration changes induced by the growth of 3D Ag islands and the occurrence
of an Ehrlich-Schwoebel diffusion barrier of 155$\pm$10meV.


title:
An investigation of a magnetic cataclysmic variable with a period of
  14.1 ks

abstract:
  Magnetic cataclysmic variables (CVs) contain a white dwarf with magnetic
field strong enough to control the accretion flow from a late type secondary.
In this paper, we discover a magnetic CV (CXOGSG J215544.4+380116) from the
$Chandra$ archive data. The X-ray light curves show a significant period of
14.1 ks, and the X-ray spectra can be described by a multi-temperature hot
thermal plasma, suggesting the source as a magnetic CV. The broad dip in the
X-ray light curve is due to the eclipse of the primary magnetic pole, and the
additional dip in the bright phase of the soft and medium bands may be caused
by the accretion stream crossing our line of sight to the primary pole.
Follow-up optical spectra show features of an M2--M4 dwarf dominating the red
band and a WD which is responsible for the weak upturn in the blue band. The
mass ($\sim$ 0.4 $M_{\odot}$) and radius ($\sim$ 0.4 $R_{\odot}$) for the M
dwarf are obtained using CV evolution models and empirical relations between
the orbital period and the mass/radius. The estimated low X-ray luminosity and
accretion rate may suggest the source as a low-accretion-rate polar. In
addition, Very Large Array observations reveal a possible radio counterpart to
the X-ray source, but with a low significance. Further radio observations with
high quality are needed to confirm the radio counterpart and explore the
properties of this binary system.


title:
Wind ramp event prediction with parallelized Gradient Boosted Regression
  Trees

abstract:
  Accurate prediction of wind ramp events is critical for ensuring the
reliability and stability of the power systems with high penetration of wind
energy. This paper proposes a classification based approach for estimating the
future class of wind ramp event based on certain thresholds. A parallelized
gradient boosted regression tree based technique has been proposed to
accurately classify the normal as well as rare extreme wind power ramp events.
The model has been validated using wind power data obtained from the National
Renewable Energy Laboratory database. Performance comparison with several
benchmark techniques indicates the superiority of the proposed technique in
terms of superior classification accuracy.


title:
Nitrile versus isonitrile adsorption at interstellar grains surfaces: I
  - Hydroxylated surfaces

abstract:
  Almost 20% of the ~ 200 different species detected in the interstellar and
circumstellar media present a carbon atom linked to nitrogen by a triple bond.
Among these 37 molecules, 30 are nitrile R-CN compounds, the remaining seven
belonging to the isonitrile R-NC family. How these species behave in presence
of the grain surfaces is still an open question. In this contribution we
investigate whether the difference between nitrile and isonitrile functional
groups may induce differences in the adsorption energies of the related isomers
at the surfaces of interstellar grains of different nature and morphologies.
The question was addressed by means of a concerted experimental and theoretical
study of the adsorption energies of CH3CN and CH3NC on the surface water ice
and silica. The experimental determination of the molecule - surface
interaction energies was carried out using temperature programmed desorption
(TPD) under an ultra-high vacuum (UHV) between 70 and 160 K. Theoretically, the
question was addressed using first principle periodic density functional theory
(DFT) to represent the organized solid support. The most stable isomer (CH3CN)
interacts more efficiently with the solid support than the higher energy isomer
(CH3NC) for water ice and silica. Comparing with the HCN and HNC pair of
isomers, the simulations show an opposite behaviour, in which isonitrile HNC
are more strongly adsorbed than nitrile HCN provided that hydrogen bonds are
compatible with the nature of the model surface. The present study confirms
that the strength of the molecule surface interaction between isomers is not
related to their intrinsic stability but instead to their respective ability to
generate different types of hydrogen bonds.


title: Interactive Attention for Neural Machine Translation

abstract:
  Conventional attention-based Neural Machine Translation (NMT) conducts
dynamic alignment in generating the target sentence. By repeatedly reading the
representation of source sentence, which keeps fixed after generated by the
encoder (Bahdanau et al., 2015), the attention mechanism has greatly enhanced
state-of-the-art NMT. In this paper, we propose a new attention mechanism,
called INTERACTIVE ATTENTION, which models the interaction between the decoder
and the representation of source sentence during translation by both reading
and writing operations. INTERACTIVE ATTENTION can keep track of the interaction
history and therefore improve the translation performance. Experiments on NIST
Chinese-English translation task show that INTERACTIVE ATTENTION can achieve
significant improvements over both the previous attention-based NMT baseline
and some state-of-the-art variants of attention-based NMT (i.e., coverage
models (Tu et al., 2016)). And neural machine translator with our INTERACTIVE
ATTENTION can outperform the open source attention-based NMT system Groundhog
by 4.22 BLEU points and the open source phrase-based system Moses by 3.94 BLEU
points averagely on multiple test sets.


title: Two-loop corrections to the triple Higgs boson production cross section

abstract:
  In this paper we compute the QCD corrections for the triple Higgs boson
production cross section via gluon fusion, within the heavy-top approximation.
We present, for the first time, analytical results for the next-to-leading
order corrections, and also compute the soft and virtual contributions of the
next-to-next-to-leading order cross section. We provide predictions for the
total cross section and the triple Higgs invariant mass distribution. We find
that the QCD corrections are large at both perturbative orders, and that the
scale uncertainty is substantially reduced when the second order perturbative
corrections are included.


title:
General expressions for extra-dimensional tree amplitudes and all-plus
  1-loop integrands in Q-cut representaion

abstract:
  In this paper, we give the general expressions for a special series of tree
amplitudes of the Yang-Mills theory. This series of amplitudes have two
adjacent massless spin-1 particles with extra-dimensional momenta and any
number of positive helicity gluons. With special helicity choices, we use the
spinor helicity formalism to express these n-point amplitudes in compact forms,
and find a clever way to use the BCFW recursion relations to prove the results.
Then these amplitudes are used to form the complete 1-loop all-plus integrand
with any number of gluons, expressed in the Q-cut representation.


title: Nonlocal quark model description of a composite Higgs particle

abstract:
  We propose a description of the Higgs boson as top-antitop quark bound state
within a nonlocal relativistic quark model of Nambu - Jona-Lasinio type. In
contrast to model with local four-fermion interaction, the mass of the scalar
bound state can be lighter than the sum of its constituents. This is achieved
by adjusting the interaction range and the value of the coupling constant to
experimental data, for both the top quark mass and the scalar Higgs boson mass,
which can simultaneously be described.


title:
A Pointing Solution for the Medium Size Telescopes for the Cherenkov
  Telescope Array

abstract:
  An important aspect of the calibration of the Cherenkov Telescope Array is
the pointing, which enables an exact alignment of each telescope and therefore
allows to transform a position in the sky to a point in the plane of the
Cherenkov camera and vice versa. The favoured approach for the pointing
calibration of the medium size telescopes (MST) is the installation of an
optical CCD-camera in the dish of the telescope that captures the position of
the Cherenkov camera and of the stars in the night sky simultaneously during
data taking. The adaption of this approach is presented in this proceeding.


title: Weekly maintenance scheduling using exact and genetic methods

abstract:
  The weekly maintenance schedule specifies when maintenance activities should
be performed on the equipment, taking into account the availability of workers
and maintenance bays, and other operational constraints. The current approach
to generating this schedule is labour intensive and requires coordination
between the maintenance schedulers and operations staff to minimise its impact
on the operation of the mine. This paper presents methods for automatically
generating this schedule from the list of maintenance tasks to be performed,
the availability roster of the maintenance staff, and time windows in which
each piece of equipment is available for maintenance. Both Mixed-Integer Linear
Programming (MILP) and genetic algorithms are evaluated, with the genetic
algorithm shown to significantly outperform the MILP. Two fitness functions for
the genetic algorithm are also examined, with a linear fitness function
outperforming an inverse fitness function by up to 5% for the same calculation
time. The genetic algorithm approach is computationally fast, allowing the
schedule to be rapidly recalculated in response to unexpected delays and
breakdowns.


title:
Analysis of the grad-div stabilization for the time-dependent
  Navier-Stokes equations with inf-sup stable finite elements

abstract:
  This paper studies inf-sup stable finite element discretizations of the
evolutionary Navier--Stokes equations with a grad-div type stabilization. The
analysis covers both the case in which the solution is assumed to be smooth and
consequently has to satisfy nonlocal compatibility conditions as well as the
practically relevant situation in which the nonlocal compatibility conditions
are not satisfied. The constants in the error bounds obtained do not depend on
negative powers of the viscosity. Taking into account the loss of regularity
suffered by the solution of the Navier--Stokes equations at the initial time in
the absence of nonlocal compatibility conditions of the data, error bounds of
order $\mathcal O(h^2)$ in space are proved. The analysis is optimal for
quadratic/linear inf-sup stable pairs of finite elements. We also consider the
analysis of the fully discrete case with the backward Euler method as time
integrator.


title:
An explicit formula for optimal portfolios in complete Wiener driven
  markets: a functional It\^o calculus approach

abstract:
  We consider a standard optimal investment problem in a complete financial
market driven by a Wiener process and derive an explicit formula for the
optimal portfolio process in terms of the vertical derivative from functional
It^o calculus. An advantage with this approach compared to the Malliavin
calculus approach is that it relies only on an integrability condition.


title: Hirzebruch-type inequalities and plane curve configurations

abstract:
  In this paper we come back to a problem proposed by F. Hirzebruch in the
1980's, namely whether there exists a configuration of smooth conics in the
complex projective plane such that the associated desingularization of the
Kummer extension is a ball quotient. We extend our considerations to the
so-called $d$-configurations of curves on the projective plane and we show that
in most cases for a given configuration the associated desingularization of the
Kummer extension is not a ball quotient. Moreover, we provide improved versions
of Hirzebruch-type inequality for $d$-configurations. Finally, we show that the
so-called characteristic numbers (or $\gamma$ numbers) for $d$-configurations
are bounded from above by $8/3$. At the end of the paper we give some examples
of surfaces constructed via Kummer extensions branched along conic
configurations.


title: DDVV-type inequality for Hermitian matrices

abstract:
  In this paper we extend DDVV-type inequalities involving the Frobenius norm
of commutators from real symmetric and skew-symmetric matrices to Hermitian and
skew-Hermitian matrices.


title: Stochastic Linear Quadratic Optimal Control Problems in Infinite Horizon

abstract:
  This paper is concerned with stochastic linear quadratic (LQ, for short)
optimal control problems in an infinite horizon with constant coefficients. It
is proved that the non-emptiness of the admissible control set for all initial
state is equivalent to the $L^2$-stabilizability of the control system, which
in turn is equivalent to the existence of a positive solution to an algebraic
Riccati equation (ARE, for short). Different from the finite horizon case, it
is shown that both the open-loop and closed-loop solvabilities of the LQ
problem are equivalent to the existence of a static stabilizing solution to the
associated generalized ARE. Moreover, any open-loop optimal control admits a
closed-loop representation. Finally, the one-dimensional case is worked out
completely to illustrate the developed theory.


title: Sparse Accelerated Exponential Weights

abstract:
  We consider the stochastic optimization problem where a convex function is
minimized observing recursively the gradients. We introduce SAEW, a new
procedure that accelerates exponential weights procedures with the slow rate
$1/\sqrt{T}$ to procedures achieving the fast rate $1/T$. Under the strong
convexity of the risk, we achieve the optimal rate of convergence for
approximating sparse parameters in $\mathbb{R}^d$. The acceleration is achieved
by using successive averaging steps in an online fashion. The procedure also
produces sparse estimators thanks to additional hard threshold steps.


title:
A GPU-accelerated nodal discontinuous Galerkin method with high-order
  absorbing boundary conditions and corner/edge compatibility

abstract:
  Discontinuous Galerkin finite element schemes exhibit attractive features for
accurate large-scale wave-propagation simulations on modern parallel
architectures. For many applications, these schemes must be coupled with
non-reflective boundary treatments to limit the size of the computational
domain without losing accuracy or computational efficiency, which remains a
challenging task. In this paper, we present a combination of a nodal
discontinuous Galerkin method with high-order absorbing boundary conditions
(HABCs) for cuboidal computational domains. Compatibility conditions are
derived for HABCs intersecting at the edges and the corners of a cuboidal
domain. We propose a GPU implementation of the computational procedure, which
results in a multidimensional solver with equations to be solved on 0D, 1D, 2D
and 3D spatial regions. Numerical results demonstrate both the accuracy and the
computational efficiency of our approach.


title:
Dimensional Crossover in a Charge Density Wave Material Probed by
  Angle-Resolved Photoemission Spectroscopy

abstract:
  High-resolution angle-resolved photoemission spectroscopy (ARPES) data reveal
evidence of a crossover from one-dimensional (1D) to three-dimensional (3D)
behavior in the prototypical charge density wave (CDW) material NbSe3. In the
low-temperature 3D regime, gaps in the electronic structure are observed due to
two incommensurate CDWs, in agreement with x-ray diffraction and
electronic-structure calculations. At higher temperatures we observe a spectral
weight depletion that approaches the power-law behavior expected in 1D. From
the warping of the quasi-1D Fermi surface at low temperatures, we extract the
energy scale of the dimensional crossover. This is corroborated by a detailed
analysis of the density of states, which reveals a change in dimensional
behavior dependent on binding energy. Our results offer an important insight
into the dimensionality of excitations in quasi-1D materials.


title: PHENIX results on L\'evy analysis of Bose-Einstein correlation functions

abstract:
  The nature of the quark-hadron phase transition can be investigated through
analyzing the space-time structure of the hadron emission source. For this, the
Bose-Einstein or HBT correlations of identified charged particles are among the
best observables. In this paper we present the latest results from the RHIC
PHENIX experiment on such measurements.


title: Boundedness of Lebesgue constants and interpolating Faber bases

abstract:
  We investigate some conditions under which the Lebesgue constants or Lebesgue
functions are bounded for the classical Lagrange polynomial interpolation on a
compact subset of $\mathbb R$. In particular, relationships of such boundedness
with uniform and pointwise convergence of Lagrange polynomials and with the
existence of interpolating Faber bases are discussed.


title: Stability with respect to actions of real reductive Lie groups

abstract:
  We give a systematic treatment of the stability theory for action of a real
reductive Lie group G on a topological space. More precisely, we introduce an
abstract setting for actions of non-compact real reductive Lie groups on
topological spaces that admit functions similar to the Kempf-Ness function. The
point of this construction is that one can characterize stability,
semi-stability and polystability of a point by numerical criteria, that is in
terms of a function called maximal weight. We apply this setting to the actions
of a real non-compact reductive Lie group G on a real compact submanifold M of
a Kaehler manifold Z and to the action of G on measures of M.


title: What Can We Learn From Analogue Experiments?

abstract:
  In 1981 Unruh proposed that fluid mechanical experiments could be used to
probe key aspects of the quantum phenomenology of black holes. In particular,
he claimed that an analogue to Hawking radiation could be created within a
fluid mechanical `dumb hole', with the event horizon replaced by a sonic
horizon. Since then an entire sub-field of `analogue gravity' has been created.
In 2016 Steinhauer reported the experimental observation of quantum Hawking
radiation and its entanglement in a Bose-Einstein condensate analogue black
hole. What can we learn from such analogue experiments? In particular, in what
sense can they provide evidence of novel phenomena such as black hole Hawking
radiation?


title:
An algorithmic comparison of the Hyper-Reduction and the Discrete
  Empirical Interpolation Method for a nonlinear thermal problem

abstract:
  A novel algorithmic discussion of the methodological and numerical
differences of competing parametric model reduction techniques for nonlinear
problems are presented. First, the Galerkin reduced basis (RB) formulation is
presented which fails at providing significant gains with respect to the
computational efficiency for nonlinear problems. Renown methods for the
reduction of the computing time of nonlinear reduced order models are the
Hyper-Reduction and the (Discrete) Empirical Interpolation Method (EIM, DEIM).
An algorithmic description and a methodological comparison of both methods are
provided. The accuracy of the predictions of the hyper-reduced model and the
(D)EIM in comparison to the Galerkin RB is investigated. All three approaches
are applied to a simple uncertainty quantification of a planar nonlinear
thermal conduction problem. The results are compared to computationally intense
finite element simulations.


title: On nilpotent Chernikov 2-groups with elementary tops

abstract:
  We give an explicit description of nilpotent Chernikov 2-groups with
elementary tops and the basis of rank 2.


title:
Understanding Active Galactic Nuclei using near-infrared high angular
  resolution polarimetry II: Preliminary results

abstract:
  In this second research note of a series of two, we present the first
near-infrared results we obtained when modeling Active Galactic Nuclei (AGN).
Our first proceedings showed the comparison between the MontAGN and STOKES
Monte Carlo codes. Now we use our radiative transfer codes to simulate the
polarization maps of a prototypical, NGC 1068-like, type-2 radio-quiet AGN. We
produced high angular resolution infrared (1 micron) polarization images to be
compared with recent observations in this wavelength range. Our preliminary
results already show a good agreement between the models and observations but
cannot account for the peculiar linear polarization angle of the torus such as
observed. Gratadour et al. 2015 found a polarization position angle being
perpendicular to the bipolar outflows axis. Further work is needed to improve
the models by adding physical phenomena such as dichroism and clumpiness.


title:
Spectral imbalance in the inertial range dynamics of decaying rotating
  turbulence

abstract:
  Direct numerical simulations of homogeneous decaying turbulence with mild
background rotation show the existence of a systematic and significant
imbalance between the non-linear energy cascade to small scales and its
dissipation. By starting the decay from a statistically stationary and fully
developed rotating turbulence state, where the dissipation and the energy flux
are approximately equal, the data shows a growing imbalance between the two
until a maximum is reached when the dissipation is about twice the energy flux.
This dichotomy of behaviours during decay is reminiscent of the non-equilibrium
and the equilibrium regions previously reported for non-rotating turbulence
[P.C. Valente, J.C. Vassilicos, Phys. Rev. Lett. {\bf 108} 214503 (2012)].
Note, however, that for decaying rotating turbulence the classical scaling of
the dissipation rate $\epsilon \propto u'^3/L$ (where $u'$ and $L$ are the root
mean square fluctuating velocity and the integral length scale, respectively)
does not appear to hold during decay, which may be attributed to the effect of
the background rotation on the energy cascade. On the other hand, the maximum
energy flux holds the scaling $\Pi_{max} \propto u'^3/L$ in the initial stage
of the decay until the maximum imbalance is reached.


title: On Cohen-Macaulay modules over the plane curve singularity of type T_44

abstract:
  For a wide class of Cohen--Macaulay modules over the local ring of the plane
curve singularity of type T_44 we explicitly describe the corresponding matrix
factorizations. The calculations are based on the technique of matrix problems,
in particular, representations of bunches of chains.


title: Topological Phase Transition in Metallic Single-Wall Carbon Nanotube

abstract:
  The topological phase transition is theoretically studied in a metallic
single-wall carbon nanotube (SWNT) by applying a magnetic field $B$ parallel to
the tube. The $\mathbb{Z}$ topological invariant, winding number, is changed
discontinuously when a small band gap is closed at a critical value of $B$,
which can be observed as a change in the number of edge states owing to the
bulk-edge correspondence. This is confirmed by numerical calculations for
finite SWNTs of $\sim$ 1 $\mu$m length, using a one-dimensional lattice model
to effectively describe the mixing between $\sigma$ and $\pi$ orbitals and
spin-orbit interaction, which are relevant to the formation of the band gap in
metallic SWNTs.


title: Non-parametric estimation of conditional densities: A new method

abstract:
  Let $\textbf{X} = (X_1,\ldots, X_p)$ be a stochastic vector having joint
density function $f_{\textbf{X}}(x)$ with partitions $\textbf{X}_1 =
(X_1,\ldots, X_k)$ and $\textbf{X}_2 = (X_{k+1},\ldots, X_p)$. A new method for
estimating the conditional density function of $\textbf{X}_1$ given
$\textbf{X}_2$ is presented. It is based on locally Gaussian approximations,
but simplified in order to tackle the curse of dimensionality in multivariate
applications, where both response and explanatory variables can be vectors. We
compare our method to some available competitors, and the error of
approximation is shown to be small in a series of examples using real and
simulated data, and the estimator is shown to be particularly robust against
noise caused by independent variables. We also present examples of practical
applications of our conditional density estimator in the analysis of time
series. Typical values for $k$ in our examples are 1 and 2, and we include
simulation experiments with values of $p$ up to 6. Large sample theory is
established under a strong mixing condition.


title:
Encoding the Local Connectivity Patterns of fMRI for Cognitive State
  Classification

abstract:
  In this work, we propose a novel framework to encode the local connectivity
patterns of brain, using Fisher Vectors (FV), Vector of Locally Aggregated
Descriptors (VLAD) and Bag-of-Words (BoW) methods. We first obtain local
descriptors, called Mesh Arc Descriptors (MADs) from fMRI data, by forming
local meshes around anatomical regions, and estimating their relationship
within a neighborhood. Then, we extract a dictionary of relationships, called
\textit{brain connectivity dictionary} by fitting a generative Gaussian mixture
model (GMM) to a set of MADs, and selecting the codewords at the mean of each
component of the mixture. Codewords represent the connectivity patterns among
anatomical regions. We also encode MADs by VLAD and BoW methods using the
k-Means clustering.
  We classify the cognitive states of Human Connectome Project (HCP) task fMRI
dataset, where we train support vector machines (SVM) by the encoded MADs.
Results demonstrate that, FV encoding of MADs can be successfully employed for
classification of cognitive tasks, and outperform the VLAD and BoW
representations. Moreover, we identify the significant Gaussians in mixture
models by computing energy of their corresponding FV parts, and analyze their
effect on classification accuracy. Finally, we suggest a new method to
visualize the codewords of brain connectivity dictionary.


title:
Pseudogap and (an)isotropic scattering in the fluctuating charge-density
  wave phase of cuprates

abstract:
  We present a general scenario for high-temperature superconducting cuprates,
based on the presence of dynamical charge density waves (CDWs) and to the
occurrence of a CDW quantum critical point, which occurs, e.g., at doping
p~0.16 in YBCO. In this framework, even the pseudogap temperature T* is
interpreted in terms of a reduction of the density of states due to incipient
CDW and, at lower temperature to the possible formation of incoherent
superconducting pairs. The dynamically fluctuating character of CDW accounts
for the different temperatures at which the pseudogap (T*), the CDW onset
revealed by X-ray scattering (T_{ons}(p)), and the static three-dimensional CDW
ordering appear. We also investigate the anisotropic character of the
CDW-mediated scattering. We find that this is strongly anisotropic only close
to the CDW quantum critical point (QCP) at low temperature and very low energy.
It rapidly becomes nearly isotropic and marginal-Fermi-liquid-like away from
the CDW QCP and at finite (even rather small) energies. This may reconcile the
interpretation of Hall measurements in terms of anisotropic CDW scattering with
recent photoemission experiments.


title:
Schr\"odinger field theory in curved spacetime: In-In formalism and
  three-point function for inflationary background

abstract:
  We review the Schr\"odinger picture of field theory in curved spacetime and
using this formalism, the power spectrum of massive non-interacting, minimally
coupled scalars in a fixed de Sitter background is obtained. To calculate the
N-point function in Schr\"odinger field theory, the "in-in" formalism is
extended in the Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe. We
compute the three-point function for primordial scalar field fluctuation in the
single field inflation by this in-in formalism. The results are the same as the
three-point function in the Heisenberg picture.


title: The odd-even invariant and Hamiltonian circuits in tope graphs

abstract:
  In this paper we consider the question of the existence of Hamiltonian
circuits in the tope graphs of central arrangements of hyperplanes. Some of the
results describe connections between the existence of Hamiltonian circuits in
the arrangement and the odd-even invariant of the arrangement. In conjunction
with this, we present some results concerning bounds on the odd-even invariant.
The results given here can be formulated more generally for oriented matroids
and are still valid in that setting.


title: SM*A*S*H

abstract:
  We present a minimal model for particle physics and cosmology. The Standard
Model (SM) particle content is extended by three right-handed SM-singlet
neutrinos N_i and a vector-like quark Q, all of them being charged under a
global lepton number and Peccei-Quinn (PQ) U(1) symmetry which is spontaneously
broken by the vacuum expectation value v_sigma around 10^{11} GeV of a
SM-singlet complex scalar field sigma. Five fundamental problems -- neutrino
oscillations, baryogenesis, dark matter, inflation, strong CP problem -- are
solved at one stroke in this model, dubbed "SM*A*S*H" (Standard
Model*Axion*Seesaw*Higgs portal inflation). It can be probed decisively by
upcoming cosmic microwave background and axion dark matter experiments.


title:
Momentum and doping dependence of spin excitations in electron-doped
  cuprate superconductors

abstract:
  Superconductivity in copper oxides emerges on doping holes or electrons into
their Mott insulating parent compounds. The spin excitations are thought to be
the mediating glue for the pairing in superconductivity. Here the momentum and
doping dependence of the dynamical spin response in the electron-doped cuprate
superconductors is studied based on the kinetic-energy-driven superconducting
mechanism. It is shown that the dispersion of the low-energy spin excitations
changes strongly upon electron doping, however, the hour-glass-shaped
dispersion of the low-energy spin excitations appeared in the hole-doped side
is absent in the electron-doped case due to the electron-hole asymmetry. In
particular, the commensurate resonance appears in the superconducting-state
with the resonance energy that correlates with the dome-shaped doping
dependence of the superconducting gap. Moreover, the spectral weight and
dispersion of the high-energy spin excitations in the superconducting-state are
comparable with those in the corresponding normal-state, indicating that the
high-energy spin excitations do not play an important part in the pair
formation.


title: An ideal-based cozero-divisor graph of a commutative ring

abstract:
  Let $R$ be a commutative ring and let $I$ be an ideal of $R$. In this paper,
we introduce the cozero-divisor graph $\acute{\Gamma}_I(R)$ of $R$ and obtain
some related results.


title:
Use of Anodic TiO2 Nanotube Layers as Mesoporous Scaffolds for
  Fabricating CH3NH3PbI3 Perovskite-based Solid State Solar Cells

abstract:
  We optimize the deposition of CH3NH3PbI3 perovskite into mesoporous
electrodes consisting of anodic TiO2 nanotube layers. By a simple spin coating
approach, complete filling of the tube scaffolds is obtained, that leads to
interdigitated perovskite structures in conformal contact with the TiO2 tube
counterparts. Such assemblies can be used as solid state solar cells in
hole-transporting material-free configuration, i.e., the tube scaffold serves
as electron collector and blocking layer, while the perovskite acts as visible
light absorber and hole transporting material. We show that the complete
filling of the tube scaffold with the perovskite is essential to improve the
solar cell efficiency.


title:
Isoperimetric inequalities for finite perimeter sets under lower Ricci
  curvature bounds

abstract:
  We prove that the results regarding the Isoperimetric inequality and Cheeger
constant formulated in terms of the Minkowski content, obtained by the authors
in previous papers in the framework of essentially non-branching metric measure
spaces verifying the local curvature dimension condition, also hold in the
stronger formulation in terms of the perimeter.


title: Validation of community robustness

abstract:
  The large amount of work on community detection and its applications leaves
unaddressed one important question: the statistical validation of the results.
In this paper we present a methodology able to clearly detect if the community
structure found by some algorithms is statistically significant or is a result
of chance, merely due to edge positions in the network. Given a community
detection method and a network of interest, our proposal examines the stability
of the partition recovered against random perturbations of the original graph
structure. To address this issue, we specify a perturbation strategy and a null
model to build a set of procedures based on a special measure of clustering
distance, namely Variation of Information, using tools set up for functional
data analysis. The procedures determine whether the obtained clustering departs
significantly from the null model. This strongly supports the robustness
against perturbation of the algorithm used to identify the community structure.
We show the results obtained with the proposed technique on simulated and real
datasets.


title:
Mean Field Dynamics of Graphs II: Assessing the Risk for the Development
  of Phase Transitions in Empirical Data

abstract:
  Psychological disorders like major depressive disorder can be seen as complex
dynamical systems. By looking at symptom activation patterns, we can
investigate the dynamic behaviour of individuals to see whether or not they are
at risk for sudden changes (phase transitions). Here, we show how a mean field
approximation is used to reduce a dynamic multidimensional system to
one-dimensional system to analyse the dynamics. Using maximum likelihood
estimation, we can estimate the parameter of interest which, in combination
with a bifurcation diagram, reflects the risk that someone has for experiencing
a transition. After validating the proposed method with simulated data, we
apply this method to three empirical examples, where we validate our method
using data that contains a transition, and where we show its use in a clinical
and general sample. Results show an increased risk for a transition when the
transition actually occurred, and that members of both the clinical and general
sample were not susceptible to transitions from a healthy to a depressed mood,
or vice versa. We conclude that the mean field approximation is valid to assess
the risk for a transition, and could in the future aid clinical therapists in
the treatment of depressed patient.


title: Deep Learning Prototype Domains for Person Re-Identification

abstract:
  Person re-identification (re-id) is the task of matching multiple occurrences
of the same person from different cameras, poses, lighting conditions, and a
multitude of other factors which alter the visual appearance. Typically, this
is achieved by learning either optimal features or matching metrics which are
adapted to specific pairs of camera views dictated by the pairwise labelled
training datasets. In this work, we formulate a deep learning based novel
approach to automatic prototype-domain discovery for domain perceptive
(adaptive) person re-id (rather than camera pair specific learning) for any
camera views scalable to new unseen scenes without training data. We learn a
separate re-id model for each of the discovered prototype-domains and during
model deployment, use the person probe image to select automatically the model
of the closest prototype domain. Our approach requires neither supervised nor
unsupervised domain adaptation learning, i.e. no data available from the target
domains. We evaluate extensively our model under realistic re-id conditions
using automatically detected bounding boxes with low-resolution and partial
occlusion. We show that our approach outperforms most of the state-of-the-art
supervised and unsupervised methods on the latest CUHK-SYSU and PRW benchmarks.


title:
Origin and Ion Charge State Evolution of Solar Wind Transients during 4
  -- 7 August 2011

abstract:
  We present study of the complex event consisting of several solar wind
transients detected by Advanced Composition Explorer (ACE) on 4 -- 7 August
2011, that caused a geomagnetic storm with Dst$=-$110 nT. The supposed coronal
sources -- three flares and coronal mass ejections (CMEs) occurred on 2 -- 4
August 2011 in the active region (AR) 11261. To investigate the solar origin
and formation of these transients we studied kinematic and thermodynamic
properties of the expanding coronal structures using the Solar Dynamics
Observatory/Atmospheric Imaging Assembly (SDO/AIA) EUV images and the
differential emission measure (DEM) diagnostics. The Helioseismic and Magnetic
Imager (HMI) magnetic field maps were used as the input data for the 3D
magnetohydrodynamic (MHD) model to describe the flux rope ejection. We
characterize the early phase of the flux rope ejection in the corona, where the
usual three-component CME structure formed. The flux rope ejected with a speed
of about 200~km~s$^{-1}$ to the height of 0.25~R$_{\odot}$. The kinematics of
the modeled CME front agrees well with the Solar Terrestrial Relations
Observatory (STEREO) EUV measurements. Using the results of the plasma
diagnostics and MHD modeling, we calculated the ion charge ratios of carbon and
oxygen as well as the mean charge state of iron ions of the 2 August 2011 CME,
taking into account the processes of heating, cooling, expansion, ionization,
and recombination of the moving plasma in the corona up to the frozen-in
region. We estimated a probable heating rate of the CME plasma in the low
corona by matching the calculated ion composition parameters of the CME with
those measured in situ for the solar wind transients. We also consider the
similarities and discrepancies between the results of the MHD simulation and
the observations.


title:
Statistics of Turbulence Parameters at Maunakea using multiple
  wave-front sensor data of RAVEN

abstract:
  Prior statistical knowledge of the atmospheric turbulence is essential for
designing, optimizing and evaluating tomographic adaptive optics systems. We
present the statistics of the vertical profiles of $C_N^2$ and the outer scale
at Maunakea estimated using a Slope Detection And Ranging (SLODAR) method from
on-sky telemetry taken by RAVEN, which is a MOAO demonstrator in the Subaru
telescope. In our SLODAR method, the profiles are estimated by a fit of the
theoretical auto- and cross-correlation of measurements from multiple
Shack-Haltmann wavefront sensors to the observed correlations via the
non-linear Levenberg-Marquardt Algorithm (LMA), and the analytic derivatives of
the spatial phase structure function with respect to its parameters for the LMA
are also developed. The estimated profile has the median total seeing of
0.460$^{\prime\prime}$ and large $C_N^2$ fraction of the ground layer of 54.3%.
The $C_N^2$ profile has a good agreement with the result from literatures,
except for the ground layer. The median value of the outer scale is 25.5m and
the outer scale is larger at higher altitudes, and these trends of the outer
scale are consistent with findings in literatures.


title: Probing the surface magnetic field structure in RX J1856.5-3754

abstract:
  The evolution of magnetic field in isolated neutron stars is one of the most
important ingredients in the attempt to build a unified description of these
objects. A prediction of field evolution models is the existence of an
equilibrium configuration, in which the Hall cascade vanishes. Recent
calculations have explored the field structure in this stage, called the Hall
attractor. We use X-ray data of near-by, cooling neutron stars to probe this
prediction, as these sources are surmised to be close to or at Hall attractor
phase. We show that the source RX J1856.5-3754 might be closer to the attractor
than other sources of its class. Our modelling indicates that the properties of
surface thermal emission, assuming that the star is in the Hall attractor, are
in contradiction with the spectral data of RX J1856.5-3754.


title: Asynchronous Discrete Event Schemes for PDEs

abstract:
  A new class of asynchronous discrete-event simulation schemes for
advection-diffusion-reaction equations are introduced, which is based on the
principle of allowing quanta of mass to pass through faces of a Cartesian
finite volume grid. The timescales of these events are linked to the flux on
the the face, and the schemes are self-adaptive, local in time and space.
Experiments are performed on realistic physical systems related to porous media
flow applications, including a large 3D advection diffusion equation and
advection diffusion reaction systems. The results are compared to highly
accurate results where the temporal evolution is computed with exponential
integrator schemes using the same finite volume discretisation. This allows a
reliable estimation of the solution error. Our results indicate a first order
convergence of the error as a control parameter is decreased.


title: Theoretical study of anisotropic layered antiferromagnets

abstract:
  We develop the field theory of antiferromagnets to layered structures on BCT
crystal lattices with nearest-neibour and next-nearest-neighbour ferro- and/or
antiferromagnetic interactions. For this aim the field theoretical counterpart
of a lattice Heisenberg model is derived by standard theoretical methods:
Hubbard-Stratonovich transformation and a generalized mean-field approach. We
shown that the inter-layer interactions are a pure thermal fluctuation effect
whereas the ground state is characterized by a perfect in-layer
antiferromagnetic order and a lack of inter-layer coupling. This is a
demonstration of 2D-3D dimensional crossover which is supposed to occur in real
antiferromagnets, for example, in the spin-dimer antiferromagnet BaCuSi2O6.


title: Pach's selection theorem does not admit a topological extension

abstract:
  Let $U_1,\dots, U_{d+1}$ be $n$-element sets in $R^d$ and let $\langle
u_1,\ldots,u_{d+1}\rangle$ denote the convex hull of points $u_i$ in $U_i$ (for
all $i$) which is a (possibly degenerate) simplex. Pach's selection theorem
says that there are sets $Z_1 \subset U_1,\dots, Z_{d+1} \subset U_{d+1}$ and a
point $u$ in $R^d$ such that each $|Z_i| > c_1(d)n$ and $u$ belongs to $\langle
z_1,...,z_{d+1} \rangle$ for every choice of $z_1$ in $Z_1,\dots,z_{d+1}$ in
$Z_{d+1}$. Here we show that this theorem does not admit a topological
extension with linear size sets $Z_i$. However, there is a topological
extension where each $|Z_i|$ is of order $(\log n)^(1/d)$.


title:
Measurement of fluence, LET, and dose in a carbon ion spread-out
  Bragg-peak using fluorescent nuclear track detectors and an automated reader

abstract:
  For the assessment of radiation effects of clinical ion-beams, dosimetry has
to be complemented by information on particle-energy distribution or related
quantities. Fluorescence nuclear track detectors made from C,Mg-doped alumina
single crystals allow for the quantification of ion track density and energy
loss on a single-track basis. In this study, their feasibility and accuracy to
quantify fluence, linear-energy-transfer (LET) distributions, and eventually
dose for a spread-out carbon ion Bragg peak was investigated. We found that the
primary ions track densities agreed well with the reference data, but the
determination of the individual detector sensitivity represented a major source
of uncertainty in LET (and dose) assessment. While low-LET fragments in the
beam are not contributing to this dose significantly, their number of was
largely underestimated by approximately a factor three. The effect was most
pronounced for protons where the measured fluence deviates at least an order of
magnitude. We conclude that this is mainly caused by the wide angular
distribution of protons in a carbon beam. The use of a dedicated FNTD reader
device and semi-automated workflow improved outcome due to the considerably
larger amount of data available as compared to a state-of-the-art multi-purpose
confocal laser scanning microscope.


title:
Temporal Coherence of Spatially Indirect Excitons across Bose-Einstein
  Condensation: the Role of Free Carriers

abstract:
  We study the time coherence of the photoluminescence radiated by spatially
indirect excitons confined in a 10 $\mu$m electrostatic trap. Above a critical
temperature of 1 Kelvin, we show that the photoluminescence has a homogeneous
spectral width of about 500 $\mu$eV which weakly varies with the exciton
density. By contrast, the spectral width reduces by two-fold below the critical
temperature and for experimental parameters at which excitons undergo a gray
Bose-Einstein condensation. In this regime, we find evidence showing that the
excitons temporal coherence is limited by their interaction with a
low-concentration of residual excess charges, leading to a minimum
photoluminescence spectral width of around 300 $\mu$eV.


title:
Kinetic description of collision avoidance in pedestrian crowds by
  sidestepping

abstract:
  In this paper we study a kinetic model for pedestrians, who are assumed to
adapt their motion towards a desired direction while avoiding collisions with
others by stepping aside. These minimal microscopic interaction rules lead to
complex emergent macroscopic phenomena, such as velocity alignment in
unidirectional flows and lane or stripe formation in bidirectional flows. We
start by discussing collision avoidance mechanisms at the microscopic scale,
then we study the corresponding Boltzmann-type kinetic description and its
hydrodynamic mean-field approximation in the grazing collision limit. In the
spatially homogeneous case we prove directional alignment under specific
conditions on the sidestepping rules for both the collisional and the
mean-field model. In the spatially inhomogeneous case we illustrate, by means
of various numerical experiments, the rich dynamics that the proposed model is
able to reproduce.


title:
Full Reconstruction of Non-Stationary Strand-Symmetric Models on Rooted
  Phylogenies

abstract:
  Understanding the evolutionary relationship among species is of fundamental
importance to the biological sciences. The location of the root in any
phylogenetic tree is critical as it gives an order to evolutionary events. None
of the popular models of nucleotide evolution used in likelihood or Bayesian
methods are able to infer the location of the root without exogenous
information. It is known that the most general Markov models of nucleotide
substitution can also not identify the location of the root or be fitted to
multiple sequence alignments with less than three sequences. We prove that the
location of the root and the full model can be identified and statistically
consistently estimated for a non-stationary, strand-symmetric substitution
model given a multiple sequence alignment with two or more sequences. We also
generalise earlier work to provide a practical means of overcoming the
computationally intractable problem of labelling hidden states in a
phylogenetic model.


title:
Local and global analysis of endocrine regulation as a non-cyclic
  feedback system

abstract:
  To understand the sophisticated control mechanisms of the human's endocrine
system is a challenging task that is a crucial step towards precise medical
treatment of many disfunctions and diseases. Although mathematical models
describing the endocrine system as a whole are still elusive, recently some
substantial progress has been made in analyzing theoretically its subsystems
(or axes) that regulate production of specific hormones. Many of the relevant
mathematical models are similar in structure to (or squarely based on) the
celebrated Goodwin's oscillator. Such models are convenient to explain stable
periodic oscillations at hormones' level by representing the corresponding
endocrine regulation circuits as cyclic feedback systems. However, many real
hormonal regulation mechanisms (in particular, testosterone regulation) are in
fact known to have non-cyclic structures and involve multiple feedbacks; a
Goodwin-type model thus represents only a part of such a complicated mechanism.
In this paper, we examine a new mathematical model of hormonal regulation,
obtained from the classical Goodwin's oscillator by introducing an additional
negative feedback. Local stability properties of the proposed model are
studied, and we show that the local instability of its unique equilibrium
implies oscillatory behavior of almost all solutions. Furthermore, under
additional restrictions we prove that almost all solutions converge to periodic
ones.


title:
Prediction of Nonlinear Evolution Character of Energetic-Particle-Driven
  Instabilities

abstract:
  A general criterion is proposed and found to successfully predict the
emergence of chirping oscillations of unstable Alfv\'enic eigenmodes in tokamak
plasma experiments. The model includes realistic eigenfunction structure,
detailed phase-space dependences of the instability drive, stochastic
scattering and the Coulomb drag. The stochastic scattering combines the effects
of collisional pitch angle scattering and micro-turbulence spatial diffusion.
The latter mechanism is essential to accurately identify the transition between
the fixed-frequency mode behavior and rapid chirping in tokamaks and to resolve
the disparity with respect to chirping observation in spherical and
conventional tokamaks.


title: Quantum correlations and synchronization measures

abstract:
  The phenomenon of spontaneous synchronization is universal and only recently
advances have been made in the quantum domain. Being synchronization a kind of
temporal correlation among systems, it is interesting to understand its
connection with other measures of quantum correlations. We review here what is
known in the field, putting emphasis on measures and indicators of
synchronization which have been proposed in the literature, and comparing their
validity for different dynamical systems, highlighting when they give similar
insights and when they seem to fail.


title:
Non-Destructive Testing for Black Heart Cavities in Potatoes with
  Microwave Radiation

abstract:
  A first investigation into the use of microwaves for the non-destructive
testing for the presence of black heart cavities is presented. Additionally a
potato's complex permittivity data between 0.5 GHz to 20 GHz measured using a
coaxial sensor and the recipe for a potato phantom are also presented.
Electromagnetic finite-difference time-domain simulations of potatoes show that
changes to how microwaves propagate through a potato caused by a cavity can
produce measurable changes in S21 at the potato's surface of up to 26 dB.
Lab-based readings of the change in S21 caused by a phantom cavity submerged in
a potato phantom liquid confirms the results of the simulation, albeit at a
much reduced magnitude in the order of 0.1 dB.


title:
A Framework for Application-aware Networking by Delegating Traffic
  Management of SDNs

abstract:
  Presence of a logically centralized controller in software-defined networks
enables smart and fine-grained management of network traffic. Generally,
traffic management includes measurement, analysis and control of traffic in
order to improve resource utilization. This is done by inspecting corresponding
performance requirements using metrics such as packet delay, jitter, loss rate
and bandwidth utilization from global network view. There has been many works
regarding traffic management of software-defined networks and how it could help
to efficiently allocate resources. However, the vast majority of these
solutions are bounded to indirect information retrieved within the border of
ingress and egress switches. This means that the three stage loop of
measurement, analysis and control is performed on switches in between this
border while the traffic flowing in network originates from applications on end
hosts. In this work, we present a framework for incorporating network
applications into the task of traffic management using the concept of
software-defined networking. We demonstrate how this could help applications to
receive desired level of quality of service by implementing a prototype of an
API for flow bandwidth reservation using OpenFlow and OVSDB protocols.


title:
Excitation Gap Scaling near Quantum Critical Three-Dimensional
  Antiferromagnets

abstract:
  By means of large-scale quantum Monte Carlo simulations, we examine the
quantum critical scaling of the magnetic excitation gap (the triplon gap) in a
three-dimensional dimerized quantum antiferromagnet, the bicubic lattice, and
identify characteristic multiplicative logarithmic scaling corrections atop the
leading mean-field behavior. These findings are in accord with
field-theoretical predictions that are based on an effective description of the
quantum critical system in terms of an asymptotically-free field theory, which
exhibits a logarithmic decay of the renormalized interaction strength upon
approaching the quantum critical point. Furthermore, using bond-based singlet
spectroscopy, we identify the amplitude (Higgs) mode resonance within the
antiferromagnetic region. We find a Higgs mass scaling in accord with
field-theoretical predictions that relate it by a factor of $\sqrt{2}$ to the
corresponding triplon gap in the quantum disordered regime. In contrast to the
situation in lower-dimensional systems, we observe in this three-dimensional
coupled-dimer system a distinct signal from the amplitude mode also in the
dynamical spin structure factor. The width of the Higgs mode resonance is
observed to scale linearly with the Higgs mass near criticality, indicative of
this critically well-defined excitation mode of the symmetry broken phase.


title:
Achieving while maintaining: A logic of knowing how with intermediate
  constraints

abstract:
  In this paper, we propose a ternary knowing how operator to express that the
agent knows how to achieve $\phi$ given $\psi$ while maintaining $\chi$
in-between. It generalizes the logic of goal-directed knowing how proposed by
Yanjing Wang 2015 'A logic of knowing how'. We give a sound and complete
axiomatization of this logic.


title:
Optimizing the subwavelength grating of L-band Annular Groove Phase
  Masks for high coronagraphic performance

abstract:
  Context. The Annular Groove Phase Mask (AGPM) is one possible implementation
of the vector vortex coronagraph, where the helical phase ramp is produced by a
concentric subwavelength grating. For several years, we have been manufacturing
AGPMs by etching gratings into synthetic diamond substrates using inductively
coupled plasma etching. Aims. We aim to design, fabricate, optimize, and
evaluate new L-band AGPMs that reach the highest possible coronagraphic
performance, for applications in current and forthcoming infrared high-contrast
imagers. Methods. Rigorous coupled wave analysis (RCWA) is used for designing
the subwavelength grating of the phase mask. Coronagraphic performance
evaluation is performed on a dedicated optical test bench. The experimental
results of the performance evaluation are then used to accurately determine the
actual profile of the fabricated gratings, based on RCWA modeling. Results. The
AGPM coronagraphic performance is very sensitive to small errors in etch depth
and grating profile. Most of the fabricated components therefore show moderate
performance in terms of starlight rejection (a few 100:1 in the best cases).
Here we present new processes for re-etching the fabricated components in order
to optimize the parameters of the grating and hence significantly increase
their coronagraphic performance. Starlight rejection up to 1000:1 is
demonstrated in a broadband L filter on the coronagraphic test bench, which
corresponds to a raw contrast of about 1e-5 at two resolution elements from the
star for a perfect input wave front on a circular, unobstructed aperture.
Conclusions. Thanks to their exquisite performance, our latest L-band AGPMs are
good candidates for installation in state-of-the-art and future high-contrast
thermal infrared imagers, such as METIS for the E-ELT.


title: Population dynamics in an intermittent refuge

abstract:
  Population dynamics is constrained by the environment, which needs to obey
certain conditions to support population growth. We consider a standard model
for the evolution of a single species population density, that includes
reproduction, competition for resources and spatial spreading, while subject to
an external harmful effect. The habitat is spatially heterogeneous, there
existing a refuge where the population can be protected. Temporal variability
is introduced by the intermittent character of the refuge. This scenario can
apply to a wide range of situations, from a lab setting where bacteria can be
protected by a blinking mask from ultraviolet radiation, to large scale
ecosystems, like a marine reserve where there can be seasonal fishing
prohibitions. Using analytical and numerical tools, we investigate the
asymptotic behavior of the total population as a function of the size and
characteristic time scales of the refuge. We obtain expressions for the minimal
size required for population survival, in the slow and fast time scale limits.


title:
Short-term evolution and coexistence of spots, plages and flare activity
  on LQ Hydrae

abstract:
  Four months of quasi-simultaneous spectroscopic and photometric observations
were used to study the variations of the photometric light curve, the evolution
of the chromospheric activity from the H$\alpha$ and H$\beta$ lines, and the
distribution of cool spots from Doppler maps.
  During our observations one side of the star was more active than the other.
The equivalent width of the H$\alpha$ line from the least active hemisphere
increased from ~0.7 {\AA} at the beginning of the observation to 1.0 {\AA} at
the end. The basal emission of the most active hemisphere remained roughly
constant at a H$\alpha$ EW of ~1.0 {\AA}. Intense flare activity was observed
during the first twenty days, where at least four different events were
detected. The line asymmetries of the H$\alpha$ line suggest that one of the
flares could have produced a mass ejection with a maximum projected speed of
$\mathrm{70\thinspace km\thinspace s^{-1}}$. The rotational modulation of the
V-band photometry showed clear anti-correlation with the chromospheric
activity. The difference in brightness between the opposite hemispheres
decreased from 0.16 to 0.09 mag in two months. Three spots gradually moving
apart from each other dominated the photospheric Doppler maps. The comparison
between the maps and the H$\alpha$ line as the star rotates reveals the spatial
coexistence of chromospheric H$\alpha$ emission and photospheric spots.
  Our results indicate that the active regions of LQ Hya can live for at least
four months. The detected changes in the photometric light curve and the
spectroscopic Doppler images seem to be more a consequence of the spatial
redistribution of the active regions rather than due to changes in their
strength. Only one of the active regions shows significant changes in its
chromospheric emission.


title: Gene Tree Construction and Correction using SuperTree and Reconciliation

abstract:
  The supertree problem asking for a tree displaying a set of consistent input
trees has been largely considered for the reconstruction of species trees.
Here, we rather explore this framework for the sake of reconstructing a gene
tree from a set of input gene trees on partial data. In this perspective, the
phylogenetic tree for the species containing the genes of interest can be used
to choose among the many possible compatible "supergenetrees", the most natural
criteria being to minimize a reconciliation cost. We develop a variety of
algorithmic solutions for the construction and correction of gene trees using
the supertree framework. A dynamic programming supertree algorithm for
constructing or correcting gene trees, exponential in the number of input
trees, is first developed for the less constrained version of the problem. It
is then adapted to gene trees with nodes labeled as duplication or speciation,
the additional constraint being to preserve the orthology and paralogy
relations between genes. Then, a quadratic time algorithm is developed for
efficiently correcting an initial gene tree while preserving a set of "trusted"
subtrees, as well as the relative phylogenetic distance between them, in both
cases of labeled or unlabeled input trees. By applying these algorithms to the
set of Ensembl gene trees, we show that this new correction framework is
particularly useful to correct weaklysupported duplication nodes. The C++
source code for the algorithms and simulations described in the paper are
available at https://github.com/UdeM-LBIT/SuGeT.


title: A Differential Complex for CAT(0) Cubical Spaces

abstract:
  In the 1980's Pierre Julg and Alain Valette, and also Tadeusz Pytlik and
Ryszard Szwarc, constructed and studied a certain Fredholm operator associated
to a simplicial tree. The operator can be defined in at least two ways: from a
combinatorial flow on the tree, similar to the flows in Forman's discrete Morse
theory, or from the theory of unitary operator-valued coccyges. There are
applications of the theory surrounding the operator to C*-algebra K-theory, to
the theory of completely bounded representations of groups that act on trees,
and to the Selberg principle in the representation theory of p-adic groups.
  The main aim of this paper is to extend the constructions of Julg and
Valette, and Pytlik and Szwarc, to CAT(0) cubical spaces. A secondary aim is to
illustrate the utility of the extended construction by developing an
application to operator K-theory and giving a new proof of K-amenability for
groups that act properly on bounded-geometry CAT(0)-cubical spaces.


title:
A realistic transport model with pressure dependent parameters for gas
  flow in tight porous media with application to determining shale rock
  properties

abstract:
  Shale gas recovery has seen a major boom in recent years due to the
increasing global energy demands; but the extraction technologies are very
expensive. It is therefore important to develop realistic transport modelling
and simulation methods, for porous rocks and porous media, that can compliment
the field work. Here, a new nonlinear transport model for single phase gas flow
in tight porous media is derived, incorporating many important physical
processes that occur in such porous systems: continuous flow, transition flow,
slip flow, Knudsen diffusion, adsorption and desorption in to and out of the
rock material, and a correction for high flow rates (turbulence). This produces
a nonlinear advection-diffusion type of partial differential equation (PDE)
with pressure dependent model parameters and associated compressibility
coefficients, and highly nonlinear apparent convective flux (velocity) and
apparent diffusivity. An important application is to the determination of shale
rock properties, such as porosity and permeability, by history matching of the
the simulation results to data from pressure-pulse decay tests in a shale rock
core sample [Pong K., Ho C., Liu J., Tai Y. Non-linear pressure distribution in
uniform microchannels. ASME Fluids Eng. Div. (FED) Vol. 197, 51--56, (1994)].
The estimates of the rock porosity and the permeability from our model
simulations are realistic of shale rocks, more realistic than obtained from
previous models, and illustrates the potential of the modelling strategy
presented here in producing accurate simulations of shale gas flow in tight
reservoirs.


title:
Stability Analysis and Best Approximation Error Estimates of
  Discontinuous Time-Stepping Schemes for the Allen-Cahn Equation

abstract:
  Fully-discrete approximations of the Allen-Cahn equation are considered. In
particular, we consider schemes of arbitrary order based on a discontinuous
Galerkin (in time) approach combined with standard conforming finite elements
(in space). We prove best approximation a-priori error estimates, with
constants depending polynomially ypon $(1/\epsilon)$ by circumventing
Gr\"onwall Lemma arguments. We also prove that these schemes are
unconditionally stable under minimal regularity assumptions on the given data.
The key feature of our approach is an appropriate duality argument, combined
with a boot-strap technique.


title: Formalising Real Numbers in Homotopy Type Theory

abstract:
  Cauchy reals can be defined as a quotient of Cauchy sequences of rationals.
The limit of a Cauchy sequence of Cauchy reals is defined through lifting it to
a sequence of Cauchy sequences of rationals. This lifting requires the axiom of
countable choice or excluded middle, neither of which is available in homotopy
type theory. To address this, the Univalent Foundations Program uses a higher
inductive-inductive type to define the Cauchy reals as the free Cauchy complete
metric space generated by the rationals. We generalize this construction to
define the free Cauchy complete metric space generated by an arbitrary metric
space. This forms a monad in the category of metric spaces with Lipschitz
functions. When applied to the rationals it defines the Cauchy reals. Finally,
we can use Altenkirch and Danielson (2016)'s partiality monad to define a
semi-decision procedure comparing a real number and a rational number.
  The entire construction has been formalized in the Coq proof assistant. It is
available at https://github.com/SkySkimmer/HoTTClasses/tree/CPP2017 .


title:
Prescribing the mixed scalar curvature of a foliated Riemann-Cartan
  manifold

abstract:
  The mixed scalar curvature is one of the simplest curvature invariants of a
foliated Riemannian manifold. We explore the problem of prescribing the mixed
scalar curvature of a foliated Riemann-Cartan manifold by conformal change of
the structure in tangent and normal to the leaves directions. Under certain
geometrical assumptions and in two special cases: along a compact leaf and for
a closed fibred manifold, we reduce the problem to solution of a leafwise
elliptic equation, which has three stable solutions -- only one of them
corresponds to the case of a foliated Riemannian manifold.


title:
Phase controlled metal-insulator transition in multi-leg quasiperiodic
  optical lattices

abstract:
  A tight-binding model of a multi-leg ladder network with a continuous
quasiperiodic modulation in both the site potential and the inter-arm hopping
integral is considered. The model mimics optical lattices where ultra-cold
fermionic or bosonic atoms are trapped in double well potentials. It is
observed that, the relative phase difference between the on-site potential and
the inter-arm hopping integral, which can be controlled by the tuning of the
interfering laser beams trapping the cold atoms, can result in a mixed spectrum
of one or more absolutely continuous subband(s) and point like spectral
measures. This opens up the possibility of a re-entrant metal-insulator
transition. The subtle role played by the relative phase difference mentioned
above is revealed, and we corroborate it numerically by working out the
multi-channel electronic transmission for finite two-, and three-leg ladder
networks. The extension of the calculation beyond the two-leg case is trivial,
and is discussed in the work.


title:
Employing Game theory and Multilevel Analysis to Predict the Factors
  that affect Collaborative Learning Outcomes: An Empirical Study

abstract:
  The purpose of this study is to propose a model that predicts the social and
psychological factors that affect the individuals collaborative learning
outcome in group projects. The model is established on the basis of two
theories, namely, the multilevel analysis and the cooperative game theory
(CGT). In CGT, a group of players form a coalition and a set of payoffs for
each member in the coalition. Shapely values is one of the most important
solution concepts in CGT. It represents a fair and efficient distribution of
payoffs among members of a coalition. The proposed approach was applied on a
sample that consisted of 78 freshman students, in their first semester, who
were studying philosophical thinking course and instructed by the same
professor. Tools for the data collection included self-assessments, peer
assessments, quizzes and observations. The research concluded that learning
outcome and contribution are best prophesied by the extent of engagement the
content is purveying. Whereas personality traits, as well as, learning styles
have the least impact on contribution. In addition, results show that Shapley
values can be used as good vaticinators for individuals learning outcomes.
These results indicate that CGT can be used as a good engine for analyzing
interactions that recur in collaborative learning.