title:
Probing neutrino and Higgs sectors in $SU(2)_1 \times SU(2)_2 \times
  U(1)_Y$ model with lepton-flavor non-universality

abstract:
  The neutrino and Higgs sectors in the $\mbox{SU(2)}_1 \times \mbox{SU(2)}_2
\times \mbox{U(1)}_Y $ model with lepton-flavor non-universality are discussed.
We show that active neutrinos can get Majorana masses from radiative
corrections, after adding only new singly charged Higgs bosons. The mechanism
for generation of neutrino masses is the same as in the Zee models. This also
gives a hint to solving the dark matter problem based on similar ways discussed
recently in many radiative neutrino mass models with dark matter. Except the
active neutrinos, the appearance of singly charged Higgs bosons and dark matter
does not affect significantly the physical spectrum of all particles in the
original model. We indicate this point by investigating the Higgs sector in
both cases before and after singly charged scalars are added into it. Many
interesting properties of physical Higgs bosons, which were not shown
previously, are explored. In particular, the mass matrices of charged and
CP-odd Higgs fields are proportional to the coefficient of triple Higgs
coupling $\mu$. The mass eigenstates and eigenvalues in the CP-even Higgs
sector are also presented. All couplings of the SM-like Higgs boson to normal
fermions and gauge bosons are different from the SM predictions by a factor
$c_h$, which must satisfy the recent global fit of experimental data, namely
$0.995<|c_h|<1$. We have analyzed a more general diagonalization of gauge boson
mass matrices, then we show that the ratio of the tangents of the $W-W'$ and
$Z-Z'$ mixing angles is exactly the cosine of the Weinberg angle, implying that
number of parameters is reduced by 1. Signals of new physics from decays of new
heavy fermions and Higgs bosons at LHC and constraints of their masses are also
discussed.


title: New Statistical PDFs: Predictions and Tests up to LHC Energies

abstract:
  The quantum statistical parton distributions approach proposed more than one
decade ago is revisited by considering a larger set of recent and accurate Deep
Inelastic Scattering experimental results. It enables us to improve the
description of the data by means of a new determination of the parton
distributions. This global next-to-leading order QCD analysis leads to a good
description of several structure functions, involving unpolarized parton
distributions and helicity distributions, in a broad range of $x$ and $Q^2$ and
in terms of a rather small number of free parameters. There are several
challenging issues, in particular the behavior of $\bar d(x) / \bar u(x)$ at
large $x$, a possible large positive gluon helicity distribution, etc.. The
predictions of this theoretical approach will be tested for single-jet
production and charge asymmetry in $W^{\pm}$ production in $\bar p p$ and $p p$
collisions up to LHC energies, using recent data and also for forthcoming
experimental results.


title: On chiral magnetic effect in Weyl superfluid 3He-A

abstract:
  In the theory of the chiral anomaly in relativistic quantum field theories
(RQFT) some results depend on regularization scheme at ultraviolet. In the
chiral superfluid 3He-A, which contains two Weyl points and also experiences
the effects of chiral anomaly, the "trans-Planckian" physics is known and the
results can be obtained without regularization. We discuss this on example of
the chiral magnetic effect (CME), which has been observed in 3He-A in 90's.
There are two forms of the contribution of the CME to the Chern-Simons term in
free energy, perturbative and non-perturbative. The perturbative term comes
from the fermions living in the vicinity of the Weyl point, where the fermions
are "relativistic" and obey the Weyl equation. The non-perturbative term
originates from the deep vacuum, being determined by the separation of the two
Weyl points. Both terms are obtained using the Adler-Bell-Jackiw equation for
chiral anomaly, and both agree with the results of the microscopic calculations
in the "trans-Planckian" region. Existence of the two nonequivalent forms of
the Chern-Simons term demonstrates that the results obtained within the RQFT
depend on the specific properties of the underlying quantum vacuum and may
reflect different physical phenomena in the same vacuum.


title: Charm Physics with Domain Wall Fermions and Physical Pion Masses

abstract:
  We present RBC/UKQCD's charm project using $N_f=2+1$ flavour ensembles with
inverse lattice spacings in the range $1.73-2.77\,\mathrm{GeV}$ and two
physical pion mass ensembles. Domain wall fermions are used for the light as
well as the charm quarks. We discuss our strategy for the extraction of the
decay constants $f_D$ and $f_{D_s}$ and their extrapolation to the continuum
limit, physical pion masses and the physical heavy quark mass. Our preliminary
results are $f_D=208.7(2.8)\,\mathrm{MeV}$ and
$f_{D_s}=246.4(1.9)\,\mathrm{MeV}$ where the quoted error is statistical only.
We outline our current approach to extend the reach in the heavy quark mass and
present preliminary results.


title:
Towards extracting the timelike pion form factor on CLS 2-flavour
  ensembles

abstract:
  Results are presented from an ongoing study of the $\rho$ resonance. We use
the distillation approach in order to create correlator matrices involving
$\rho$ and $\pi\pi$ interpolators. The study is done in a centre-of-mass frame
and several moving frames. We are able to extract energy levels by solving the
GEVP of those correlator matrices. The initial exploratory study is being done
on a CLS 2-flavour lattice with a pion mass of $451$ $\mathrm{MeV}$ using
$\mathcal{O}(a)$ improved Wilson fermions. One aim of this work is to extract
the timelike pion form factor after applying the L\"uscher formalism. We also
plan to integrate this study with the existing Mainz programme for the
calculation of the hadronic vacuum polarization contribution to the muon $g-2$
and will extend our study to lower pion masses and larger lattices in the
future, including ensembles with $2+1$ flavours.


title:
Attenuation of TeV $\gamma$-rays by the starlight photon field of the
  host galaxy

abstract:
  The absorption of TeV $\gamma$-ray photons produced in relativistic jets by
surrounding soft photon fields is a long-standing problem of jet physics. In
some cases the most likely emission site close to the central black hole is
ruled out because of the high opacity caused by strong optical and infrared
photon sources, such as the broad line region. Mostly neglected for jet
modeling is the absorption of $\gamma$-rays in the starlight photon field of
the host galaxy. Analyzing the absorption for arbitrary locations and
observation angles of the $\gamma$-ray emission site within the host galaxy we
find that the distance to the galaxy center, the observation angle, and the
distribution of starlight in the galaxy are crucial for the amount of
absorption. We derive the absorption value for a sample of $20$ TeV detected
blazars with a redshift $z_r<0.2$. The absorption value of the $\gamma$-ray
emission located in the galaxy center may be as high as $20\%$ with an average
value of $6\%$. This is important in order to determine the intrinsic blazar
parameters. We see no significant trends in our sample between the degree of
absorption and host properties, such as starlight emissivity, galactic size,
half-light radius, and redshift. While the uncertainty of the spectral
properties of the extragalactic background light exceeds the effect of
absorption by stellar light from the host galaxy in distant objects, the latter
is a dominant effect in nearby sources. It may also be revealed in a
differential comparison of sources with similar redshifts.


title:
A Common Optical Potential for $^{4}$He+$^{12}$C at Intermediate
  Energies

abstract:
  A common optical potential for $^4$He+$^{12}$C at intermediate bombarding
energies, which is essential in analyzing exotic nuclei with $^4$He clusters,
was obtained based on the S\~{a}o Paulo potential (SPP). Among systematic
optical potentials for $^4$He+$^{12}$C, this potential has the merit of using a
fixed imaginary part of Woods-Saxon form. By optical-model calculations, this
potential reproduced the experimental elastic scattering angular distributions
of $^4$He+$^{12}$C well within the energy range of 26\,$A$--60\,$A$ MeV. It was
also applied successfully in calculations of the breakup reactions of
$^6$Li+$^{12}$C and $^6$He+$^{12}$C with a three-body continuum discretized
coupled-channels method.


title: Extension operators for smooth functions on compact subsets of the reals

abstract:
  We introduce sufficient as well as necessary conditions for a compact set $K$
such that there is a continuous linear extension operator from the space of
restrictions $C^\infty(K)=\lbrace F|_K: F\in C^\infty(\mathbb R)\rbrace$ to
$C^\infty(\mathbb R)$. This allows us to deal with examples of the form
$K=\lbrace a_n:n\in\mathbb N\rbrace \cup \lbrace 0\rbrace$ for $a_n\to 0$
previously considered by Fefferman and Ricci as well as Vogt.


title: A study of the low-luminosity Type II-Plateau supernova 2008bk

abstract:
  Supernova (SN) 2008bk is a well observed low-luminosity Type II event
visually associated with a low-mass red-supergiant progenitor. To model SN
2008bk, we evolve a 12Msun star from the main sequence until core collapse,
when it has a total mass of 9.88Msun, a He-core mass of 3.22Msun, and a radius
of 502Rsun. We then artificially trigger an explosion that produces 8.29Msun of
ejecta with a total energy of 2.5x10^50erg and ~0.009Msun of 56Ni. We model the
subsequent evolution of the ejecta with non-Local-Thermodynamic-Equilibrium
time-dependent radiative transfer. Although somewhat too luminous and
energetic, this model reproduces satisfactorily the multi-band light curves and
multi-epoch spectra of SN 2008bk, confirming the suitability of a low-mass
massive star progenitor. As in other low-luminosity SNe II, the structured
Halpha profile at the end of the plateau phase is probably caused by BaII
6496.9A rather than asphericity. We discuss the sensitivity of our results to
changes in progenitor radius and mass, as well as chemical mixing. A 15%
increase in progenitor radius causes a 15% increase in luminosity and a 0.2mag
V-band brightening of the plateau but leaves its length unaffected. An increase
in ejecta mass by 10% lengthens the plateau by ~10d. Chemical mixing introduces
slight changes to the bolometric light curve, limited to the end of the
plateau, but has a large impact on colours and spectra at nebular times.


title: Canonical rings of Gorenstein stable Godeaux surfaces

abstract:
  Extending the description of canonical rings from \cite{reid78} we show that
every Gorenstein stable Godeaux surface with torsion of order at least $3$ is
smoothable.


title: Laser-Matter Interaction: Classical Regime versus Quantum Regime

abstract:
  Doppler backscattering of optical laser photons on a "flying mirror" of
relativistic electrons promises to yield coherent photons with MeV-range
energies. We compare the nuclear interaction of such a laser pulse with the
standard atom-laser interaction. The mean-field description of atoms must be
replaced by a rate equation and the classical field strength, far too faint in
nuclei, by the dipole transition rate. Significant nuclear excitation occurs
for photon numbers much smaller than typical for atoms. That drastically
reduces the requirements on the experimental realization of a "flying mirror".


title:
Multi-resolution anisotropy studies of ultrahigh-energy cosmic rays
  detected at the Pierre Auger Observatory

abstract:
  We report a multi-resolution search for anisotropies in the arrival
directions of cosmic rays detected at the Pierre Auger Observatory with local
zenith angles up to $80^\circ$ and energies in excess of 4 EeV ($4 \times
10^{18}$ eV). This search is conducted by measuring the angular power spectrum
and performing a needlet wavelet analysis in two independent energy ranges.
Both analyses are complementary since the angular power spectrum achieves a
better performance in identifying large-scale patterns while the needlet
wavelet analysis, considering the parameters used in this work, presents a
higher efficiency in detecting smaller-scale anisotropies, potentially
providing directional information on any observed anisotropies. No deviation
from isotropy is observed on any angular scale in the energy range between 4
and 8 EeV. Above 8 EeV, an indication for a dipole moment is captured; while no
other deviation from isotropy is observed for moments beyond the dipole one.
The corresponding $p$-values obtained after accounting for searches blindly
performed at several angular scales, are $1.3 \times 10^{-5}$ in the case of
the angular power spectrum, and $2.5 \times 10^{-3}$ in the case of the needlet
analysis. While these results are consistent with previous reports making use
of the same data set, they provide extensions of the previous works through the
thorough scans of the angular scales.


title: Integrable model of nonlinear dislocations

abstract:
  Using the continuous limit approximation in the dynamical system we study a
nonlinear partial differential equation which corresponds to the generalization
of both the Fermi-Pasta-Ulam and the Frenkel-Kontorova models. This generalized
model can be considered as a model for the description nonlinear dislocation
waves in the crystal lattice. We obtain the nonlinear partial differential
equation for the description of dislocations. Taking into account the wave
moving in one direction we obtain another nonlinear evolution equation. Using
the Painlev\'e test we analyze the integrability of this equation. We find that
there exist an integrable case of the partial differential equation for
nonlinear dislocations. The Lax pair for the solution of the Cauchy problem is
found. The solution of the Cauchy problem for nonlinear evolution equation is
discussed. One and the two-soliton solutions for the nonlinear evolution
equation are presented. The influence of parameters on the propagation of one
and the two-soliton solutions is analyzed and demonstrated.


title: Efficient numerical integration of neutrino oscillations in matter

abstract:
  A special purpose solver, based on the Magnus expansion, well suited for the
integration of the linear three neutrino oscillations equations in matter is
proposed. The computations are speeded up to two orders of magnitude with
respect to a general numerical integrator, a fact that could smooth the way for
massive numerical integration concomitant with experimental data analyses.
Detailed illustrations about numerical procedure and computer time costs are
provided.


title: Uniquely restricted matchings and edge colorings

abstract:
  A matching in a graph is uniquely restricted if no other matching covers
exactly the same set of vertices. This notion was defined by Golumbic, Hirst,
and Lewenstein and studied in a number of articles. Our contribution is
twofold. We provide approximation algorithms for computing a uniquely
restricted matching of maximum size in some bipartite graphs. In particular, we
achieve a ratio of $9/5$ for subcubic bipartite graphs, improving over a
$2$-approximation algorithm proposed by Mishra. Furthermore, we study the
uniquely restricted chromatic index of a graph, defined as the minimum number
of uniquely restricted matchings into which its edge set can be partitioned. We
provide tight upper bounds in terms of the maximum degree and characterize all
extremal graphs. Our constructive proofs yield efficient algorithms to
determine the corresponding edge colorings.


title: Service-Oriented Sharding with Aspen

abstract:
  The rise of blockchain-based cryptocurrencies has led to an explosion of
services using distributed ledgers as their underlying infrastructure. However,
due to inherently single-service oriented blockchain protocols, such services
can bloat the existing ledgers, fail to provide sufficient security, or
completely forego the property of trustless auditability. Security concerns,
trust restrictions, and scalability limits regarding the resource requirements
of users hamper the sustainable development of loosely-coupled services on
blockchains.
  This paper introduces Aspen, a sharded blockchain protocol designed to
securely scale with increasing number of services. Aspen shares the same trust
model as Bitcoin in a peer-to-peer network that is prone to extreme churn
containing Byzantine participants. It enables introduction of new services
without compromising the security, leveraging the trust assumptions, or
flooding users with irrelevant messages.


title:
Search for magnetic monopoles with the MoEDAL forward trapping detector
  in 13 TeV proton-proton collisions at the LHC

abstract:
  MoEDAL is designed to identify new physics in the form of long-lived
highly-ionising particles produced in high-energy LHC collisions. Its arrays of
plastic nuclear-track detectors and aluminium trapping volumes provide two
independent passive detection techniques. We present here the results of a
first search for magnetic monopole production in 13 TeV proton-proton
collisions using the trapping technique, extending a previous publication with
8 TeV data during LHC run-1. A total of 222 kg of MoEDAL trapping detector
samples was exposed in the forward region and analysed by searching for induced
persistent currents after passage through a superconducting magnetometer.
Magnetic charges exceeding half the Dirac charge are excluded in all samples
and limits are placed for the first time on the production of magnetic
monopoles in 13 TeV $pp$ collisions. The search probes mass ranges previously
inaccessible to collider experiments for up to five times the Dirac charge.


title:
Predicting Clinical Outcomes in Glioblastoma: An Application of
  Topological and Functional Data Analysis

abstract:
  Glioblastoma multiforme (GBM) is an aggressive form of human brain cancer
that is under active study in the field of cancer biology. Its rapid
progression and the relative time cost of obtaining molecular data make other
readily-available forms of data, such as images, an important resource for
actionable measures in patients. Our goal is to utilize information given by
medical images taken from GBM patients in statistical settings. To do this, we
design a novel statistic---the smooth Euler characteristic transform
(SECT)---that quantifies magnetic resonance images (MRIs) of tumors. Due to its
well-defined inner product structure, the SECT can be used in a wider range of
functional and nonparametric modeling approaches than other previously proposed
topological summary statistics. When applied to a cohort of GBM patients, we
find that the SECT is a better predictor of clinical outcomes than both
existing tumor shape quantifications and common molecular assays. Specifically,
we demonstrate that SECT features alone explain more of the variance in GBM
patient survival than gene expression, volumetric features, and morphometric
features. The main takeaways from our findings are thus twofold. First, they
suggest that images contain valuable information that can play an important
role in clinical prognosis and other medical decisions. Second, they show that
the SECT is a viable tool for the broader study of medical imaging informatics.


title: Coquasi-bialgebras with preantipode and rigid monoidal categories

abstract:
  By a theorem of Majid, every monoidal category with a neutral quasi-monoidal
functor to finitely-generated and projective $\Bbbk$-modules gives rise to a
coquasi-bialgebra. We prove that if the category is also rigid, then the
associated coquasi-bialgebra admits a preantipode, providing in this way an
analogue for coquasi-bialgebras of Ulbrich's reconstruction theorem for Hopf
algebras. When $\Bbbk$ is field, this allows us to characterize coquasi-Hopf
algebras as well in terms of rigidity of finite-dimensional corepresentations.


title:
From bad metal to Kondo insulator: temperature evolution of the optical
  properties of SmB$_{6}$

abstract:
  The recent rekindling of interest in the mixed valent Kondo insulator
SmB$_{6}$ as candidate for a first correlated topological insulator has
resulted in a wealth of new experimental observations. In particular,
angle-resolved photoemission experiments have provided completely new insights
into the formation of the low temperature Kondo insulating state starting from
the high temperature correlated metal. Here, we report detailed temperature and
energy dependent measurements of the optical constants of SmB$_6$ in order to
provide a detailed study from the point of view of a bulk sensitive
spectroscopic probe. We detect a previously unobserved infrared active optical
phonon mode, involving the movement of the Sm ions against the boron cages. The
changes taking place in the free carrier response with temperature and their
connection to changes in optical transitions between different bands are
discussed. We find that the free charge density starts to decrease rapidly
below approximately 200 K. Below 60 K a small amount of spectral weight begins
to accumulate in low lying interband transitions, indicating the formation of
the Kondo insulating state; however, the total integrated spectral weight in
our experimental window ($\sim 4.35$ eV) decreases. This indicates the
involvement of a large Coulomb interaction ($>$ 5 eV) in the formation of the
Kondo insulator.


title:
Discovery of a novel 112-type iron-pnictide and La-doping induced
  superconductivity in Eu1-xLaxFeAs2 (x = 0 ~ 0.15)

abstract:
  We report the discovery and characterization of a novel 112-type iron
pnictide EuFeAs2, with La-doping induced superconductivity in a series of
Eu1-xLaxFeAs2. The polycrystalline samples were synthesized through solid state
reaction method only within a very narrow temperature window around 1073 K.
Small single crystals were also grown from a flux method with the size about
100 um. The crystal structure was identified by single crystal X-ray
diffraction analysis as a monoclinic structure with space group of P21/m. From
resistivity and magnetic susceptibility measurements, we found that the parent
compound EuFeAs2 shows a Fe2+ related antiferromagnetic/structural phase
transition near 110 K and a Eu2+ related antiferromagnetic phase transition
near 40 K. La doping suppressed the both phase transitions and induced
superconducting transition with a Tc ~ 11 K for Eu0.85La0.15FeAs2.


title: Communications and Signals Design for Wireless Power Transmission

abstract:
  Radiative wireless power transfer (WPT) is a promising technology to provide
cost-effective and real-time power supplies to wireless devices. Although
radiative WPT shares many similar characteristics with the extensively studied
wireless information transfer or communication, they also differ significantly
in terms of design objectives, transmitter/receiver architectures and hardware
constraints, etc. In this article, we first give an overview on the various WPT
technologies, the historical development of the radiative WPT technology and
the main challenges in designing contemporary radiative WPT systems. Then, we
focus on discussing the new communication and signal processing techniques that
can be applied to tackle these challenges. Topics discussed include energy
harvester modeling, energy beamforming for WPT, channel acquisition, power
region characterization in multi-user WPT, waveform design with linear and
non-linear energy receiver model, safety and health issues of WPT, massive MIMO
(multiple-input multiple-output) and millimeter wave (mmWave) enabled WPT,
wireless charging control, and wireless power and communication systems
co-design. We also point out directions that are promising for future research.


title: Operations on Legendrian submanifolds

abstract:
  We focus on Legendrian submanifolds of the space of one-jets of functions,
$J^1(\mathbb{R}^n,\mathbb{R})$. We are interested in processes - operations -
that build new Legendrian submanifolds from old ones. We introduce in
particular two operations, namely the sum and the convolution, which in some
sense lift to $J^1(\mathbb{R}^n,\mathbb{R})$ the operations sum and
infimal-convolution on functions that belong to convex analysis. We show that
these operations fit well with the classical theory of generating functions.
Finally, we refine this theory so that the min-max selector of generating
functions plays its natural role.


title: Options Discovery with Budgeted Reinforcement Learning

abstract:
  We consider the problem of learning hierarchical policies for Reinforcement
Learning able to discover options, an option corresponding to a sub-policy over
a set of primitive actions. Different models have been proposed during the last
decade that usually rely on a predefined set of options. We specifically
address the problem of automatically discovering options in decision processes.
We describe a new learning model called Budgeted Option Neural Network (BONN)
able to discover options based on a budgeted learning objective. The BONN model
is evaluated on different classical RL problems, demonstrating both
quantitative and qualitative interesting results.


title: Cocenter of $p$-adic groups, II: induction map

abstract:
  In this paper, we study some relation between the cocenter $\bar H(G)$ of the
Hecke algebra $H(G)$ of a connected reductive group $G$ over an nonarchimedean
local field and the cocenter $\bar H(M)$ of its Levi subgroups $M$.
  Given any Newton component of $\bar H(G)$, we construct the induction map
$\bar i$ from the corresponding Newton component of $\bar H(M)$ to it. We show
that this map is surjective. This leads to the Bernstein-Lusztig type
presentation of the cocenter $\bar H(G)$, which generalizes the work \cite{HN2}
on the affine Hecke algebras. We also show that the map $\bar i$ we constructed
is adjoint to the Jacquet functor and in characteristic $0$, the map $\bar i$
is an isomorphism.


title:
Diffusion and Perfusion Magnetic Resonance Imaging:Fundamentals and
  Advances

abstract:
  Over the past few decades, magnetic resonance imaging has been utilized as a
powerful imaging modality to evaluate the structure and function of various
organs in the human body,such as the brain. Additionally, diffusion and
perfusion MR imaging have been increasingly used in neurovascular clinical
applications. In diffusion-weighted magnetic resonance imaging, the mobility of
water molecules is explored in order to obtain information about the
microscopic behavior of the tissues. In contrast, perfusion weighted imaging
uses tracers to exploit hemodynamic status, which enables researchers and
clinicians to consider this imaging modality as an early biomarker of certain
brain diseases. In this review, the fundamentals of physics for diffusion and
perfusion MR imaging both of which are highly sensitive to microenvironmental
alterations at the cellular level as well as their application in the treatment
of aging, Alzheimer's disease, brain tumors and cerebral ischemic injury were
discussed.


title:
The existence of designs via iterative absorption: hypergraph
  $F$-designs for arbitrary $F$

abstract:
  We solve the existence problem for $F$-designs for arbitrary $r$-uniform
hypergraphs~$F$. This implies that given any $r$-uniform hypergraph~$F$, the
trivially necessary divisibility conditions are sufficient to guarantee a
decomposition of any sufficiently large complete $r$-uniform hypergraph into
edge-disjoint copies of~$F$, which answers a question asked e.g.~by Keevash.
The graph case $r=2$ was proved by Wilson in 1975 and forms one of the
cornerstones of design theory. The case when~$F$ is complete corresponds to the
existence of block designs, a problem going back to the 19th century, which was
recently settled by Keevash. In particular, our argument provides a new proof
of the existence of block designs, based on iterative absorption (which employs
purely probabilistic and combinatorial methods).
  Our main result concerns decompositions of hypergraphs whose clique
distribution fulfills certain regularity constraints. Our argument allows us to
employ a `regularity boosting' process which frequently enables us to satisfy
these constraints even if the clique distribution of the original hypergraph
does not satisfy them. This enables us to go significantly beyond the setting
of quasirandom hypergraphs considered by Keevash. In particular, we obtain a
resilience version and a decomposition result for hypergraphs of large minimum
degree.


title: The Mann-Whitney U-statistic for $\alpha$-dependent sequences

abstract:
  We give the asymptotic behavior of the Mann-Whitney U-statistic for two
independent stationary sequences. The result applies to a large class of
short-range dependent sequences, including many non-mixing processes in the
sense of Rosenblatt. We also give some partial results in the long-range
dependent case, and we investigate other related questions. Based on the
theoretical results, we propose some simple corrections of the usual tests for
stochastic domination; next we simulate different (non-mixing) stationary
processes to see that the corrected tests perform well.


title:
An approximation result for a class of stochastic heat equations with
  colored noise

abstract:
  We show that a large class of stochastic heat equations can be approximated
by systems of interacting stochastic differential equations. As a consequence,
we prove various comparison principles extending earlier results. Among other
things, our results enable us to obtain sharp estimates on the moments of the
solution. A main technical ingredient of our method is a local limit theorem
which is of independent interest.


title:
Linear quadratic stochastic control problems with stochastic terminal
  constraint

abstract:
  We study a linear quadratic optimal control problem with stochastic
coefficients and a terminal state constraint, which may be in force merely on a
set with positive, but not necessarily full probability. Under such a partial
terminal constraint, the usual approach via a coupled system of a backward
stochastic Riccati equation and a linear backward equation breaks down. As a
remedy, we introduce a family of auxiliary problems parametrized by the
supersolutions to this Riccati equation alone. The target functional of these
problems dominates the original constrained one and allows for an explicit
description of both the optimal control policy and the auxiliary problem's
value in terms of a suitably constructed optimal signal process. This suggests
that, for the minimal supersolution of the Riccati equation, the minimizers of
the auxiliary problem coincide with those of the original problem, a conjecture
that we see confirmed in all examples understood so far.


title:
Rhythms of the collective brain: Metastable synchronization and
  cross-scale interactions in connected multitudes

abstract:
  Crowd behaviour challenges our fundamental understanding of social phenomena.
Involving complex interactions between multiple temporal and spatial scales of
activity, its governing mechanisms defy conventional analysis. Using 1.5
million Twitter messages from the 15M movement in Spain as an example of
multitudinous self-organization, we describe the coordination dynamics of the
system measuring phase-locking statistics at different frequencies using
wavelet transforms, identifying 8 frequency bands of entrained oscillations
between 15 geographical nodes. Then we apply maximum entropy inference methods
to describe Ising models capturing transient synchrony in our data at each
frequency band. The models show that 1) all frequency bands of the system
operate near critical points of their parameter space and 2) while fast
frequencies present only a few metastable states displaying all-or-none
synchronization, slow frequencies present a diversity of metastable states of
partial synchronization. Furthermore, describing the state at each frequency
band using the energy of the corresponding Ising model, we compute transfer
entropy to characterize cross-scale interactions between frequency bands,
showing 1) a cascade of upward information flows in which each frequency band
influences its contiguous slower bands and 2) downward information flows where
slow frequencies modulate distant fast frequencies.


title:
Stochastic modelling and diffusion modes for proper orthogonal
  decomposition models and small-scale flow analysis

abstract:
  We present here a new stochastic modelling in the constitution of fluid flow
reduced-order models. This framework introduces a spatially inhomogeneous
random field to represent the unresolved small-scale velocity component. Such a
decomposition of the velocity in terms of a smooth large-scale velocity
component and a rough, highly oscillating, component gives rise, without any
supplementary assumption, to a large-scale flow dynamics that includes a
modified advection term together with an inhomogeneous diffusion term. Both of
those terms, related respectively to turbophoresis and mixing effects, depend
on the variance of the unre-solved small-scale velocity component. They bring
to the reduced system an explicit subgrid term enabling to take into account
the action of the truncated modes. Besides, a decomposition of the variance
tensor in terms of diffusion modes provides a meaningful statistical
representation of the stationary or nonstationary structuration of the
small-scale velocity and of its action on the resolved modes. This supplies a
useful tool for turbulent fluid flows data analysis. We apply this methodology
to circular cylinder wake flow at Reynolds numbers Re = 300 and Re = 3900,
respectively. The finite dimensional models of the wake flows reveal the energy
and the anisotropy distributions of the small-scale diffusion modes. These
distributions identify critical regions where corrective advection effects as
well as structured energy dissipation effects take place. In providing
rigorously derived subgrid terms, the proposed approach yields accurate and
robust temporal reconstruction of the low-dimensional models.


title: Phragm\'en's sequential method with a variance criterion

abstract:
  A variant of Phragm\'en's method for proportional representation via approval
voting is briefly explored. Instead of D'Hondt's rule, this variant generalizes
Sainte-Lagu\"e's rule.


title:
Differential response of the retinal neural code with respect to the
  sparseness of natural images

abstract:
  Natural images follow statistics inherited by the structure of our physical
(visual) environment. In particular, a prominent facet of this structure is
that images can be described by a relatively sparse number of features. To
investigate the role of this sparseness in the efficiency of the neural code,
we designed a new class of random textured stimuli with a controlled sparseness
value inspired by measurements of natural images. Then, we tested the impact of
this sparseness parameter on the firing pattern observed in a population of
retinal ganglion cells recorded ex vivo in the retina of a rodent, the Octodon
degus. These recordings showed in particular that the reliability of spike
timings varies with respect to the sparseness with globally a similar trend
than the distribution of sparseness statistics observed in natural images.
These results suggest that the code represented in the spike pattern of
ganglion cells may adapt to this aspect of the statistics of natural images.


title:
Symmetry breaking, slow relaxation dynamics, and topological defects at
  the field-induced helix reorientation in MnSi

abstract:
  We report a study of the reorientation of the helimagnetic order in the
archetypal cubic chiral magnet MnSi as a function of magnetic field direction.
The reorientation process as inferred from small-angle neutron scattering, the
magnetization, and the ac susceptibility is in excellent agreement with an
effective mean-field theory taking into account the precise symmetries of the
crystallographic space group. Depending on the field and temperature history
and the direction of the field with respect to the crystalline axes, the helix
reorientation may exhibit a crossover, a first-order, or a second-order
transition. The magnetization and ac susceptibility provide evidence that the
reorientation of helimagnetic domains is associated with large relaxation times
exceeding seconds. At the second-order transitions residual Ising symmetries
are spontaneously broken at continuous elastic instabilities of the
helimagnetic order. In addition, on the time scales explored in our experiments
these transitions are hysteretic as a function of field suggesting, within the
same theoretical framework, the formation of an abundance of plastic
deformations of the helical spin order. These deformations comprise
topologically non-trivial disclinations, promising novel routes to spintronics
applications alongside skyrmions discovered recently in the same class of
materials.


title: Nano patterns self-aligned to Ga dimer rows on GaAs surfaces

abstract:
  Ion beam irradiation of semiconductors is a method to produce regular
periodic nanoscale patterns self-organized on wafer scale. At low temperatures,
the surface of semiconductors is typically amorphized by the ion beam. Above a
material dependent dynamic recrystallization temperature however, the surface
remains crystalline and ion beam irradiation produces regular arrays of faceted
ripples on III-V semiconductors. This provides a powerful single-step technique
for the production of nanostructures on a large area. On $(001)$ surfaces these
ripples are parallel to the $[1\bar{1}0]$ direction without any external
anisotropy. The origin of this self-alignment was not fully understood until
now. A simple experiment exposing the front side and back side of a GaAs$(001)$
wafer to the ion beam clarifies its origin and proves that the ripples align to
the Ga dimer rows. As the direction of Ga dimer rows rotates by 90{\deg} on the
back side, the orientation of the ripples also rotates by 90{\deg} to $[110]$.
We discuss the experimental results in view of a model where the pattern
formation is driven by creation of vacancies and ad-atoms by the ion beam and
their diffusion, which is linked to the direction of dimers on the surface.


title:
Dynamic stiffness of the contact between a carbon nanotube and a flat
  substrate in a peeling geometry

abstract:
  We study the physics of adhesion and the contact mechanics at the nanoscale
with a peeling experiment of a carbon nanotube on a flat substrate. Using an
interferometric atomic force microscope and an extended force modulation
protocol, we investigate the frequency response of the stiffness of the
nano-contact from DC to 20 kHz. We show that this dynamic stiffness is only
weakly frequency dependent, increasing by a factor 2 when the frequency grows
by 3 orders of magnitude. Such behavior may be the signature of amorphous
relaxations during the mechanical solicitation at the nano-scale.


title:
A New Algebraic Structure That Extends Fields And Allows For A True
  Division By Zero

abstract:
  To allow for Division By Zero, we develop a new algebraic structure
containing addition and multiplication called an S-Extension of a Field. This
unique structure extends a Field so that the equation $0\cdot s=x$ has exactly
one solution for every non-zero Field element $x$. Furthermore, a different
solution is obtained for each choice of $x$, making this solution unique to
that particular equation. However, the equation $0\cdot s=0$ has two or more
solutions, with no preference towards any one particular solution. This allows
us to use the usual definition of division as the solution to the equation
$0\cdot s=x$ to evaluate $x$ divided by $0$. And if $x\not=0$, every ${x\over
0}$ is a unique element that is also unique to that particular $x$ while
${0\over 0}$ remains indeterminate. This creates a Division By Zero which
significantly differs from other attempts at Division By Zero.


title:
The enabling electronic motif for topological insulation in ABO3
  perovskites and its structural stability

abstract:
  Stable oxide topological insulators (TIs) that could bring together the
traditional oxide functionalities with the dissipationless surface states of
TIs have been sought for years but none was found. Yet, heavier chalcogenides
(selenides, tellurides) were readily found to be TIs. We clarify here the basic
contradiction between TI-ness and stability which is maximal for oxides, and
trace the basic design principles necessary to identify the window of
opportunity of stable TIs. We first identify the electronic motif that can
achieve topological band inversion ("topological gene") in ABO3 as being a
lone-pair electron-rich B atom (e.g. Te, I, Bi) at the octahedral site. We then
illustrate that poorly screened oxide systems with large inversion energies can
undergo energy-lowering atomic distortions that remove the band inversion. We
identify the coexistence windows of TI functionality and structure stability
for different pressures and find that the common cubic ABO3 structures have
inversion energies lying outside this coexistence window at zero pressure but
could be moved into the coexistence window at moderate pressures. Our study
demonstrates the interplay between topological band inversion and structural
stability and traces the basic principles needed to design stable oxide
topological insulators at ambient pressures.


title: Minimal and Reduced Reversible Automata

abstract:
  A condition characterizing the class of regular languages which have several
nonisomorphic minimal reversible automata is presented. The condition concerns
the structure of the minimum automaton accepting the language under
consideration. It is also observed that there exist reduced reversible automata
which are not minimal, in the sense that all the automata obtained by merging
some of their equivalent states are irreversible. Furthermore, a sufficient
condition for the existence of infinitely many reduced reversible automata
accepting a same language is given. It is also proved that, when the language
is accepted by a unique minimal reversible automaton (that does not necessarily
coincide with the minimum deterministic automaton), then no other reduced
reversible automata accepting it can exist.


title:
Coherent perfect absorption mediated enhancement and optical bistability
  in phase conjugation

abstract:
  We study phase conjugation in a nonlinear composite slab when the counter
propagating pump waves are completely absorbed by means of coherent perfect
absorption. Under the undepleted pump approximation the coupling constant and
the phase conjugated reflectivity are shown to undergo a substantial increase
and multivalued response. The effect can be used for efficient switching of the
phase conjugated reflectivity in photonic circuits.


title: Almost tiling of the Boolean lattice with copies of a poset

abstract:
  Let $P$ be a partially ordered set. If the Boolean lattice
$(2^{[n]},\subset)$ can be partitioned into copies of $P$ for some positive
integer $n$, then $P$ must satisfy the following two trivial conditions:
  (1) the size of $P$ is a power of $2$,
  (2) $P$ has a unique maximal and minimal element.
  Resolving a conjecture of Lonc, it was shown by Gruslys, Leader and Tomon
that these conditions are sufficient as well. In this paper, we show that if
$P$ only satisfies condition (2), we can still almost partition $2^{[n]}$ into
copies of $P$. We prove that if $P$ has a unique maximal and minimal element,
then there exists a constant $c=c(P)$ such that all but at most $c$ elements of
$2^{[n]}$ can be covered by disjoint copies of $P$.


title: Joint Hacking and Latent Hazard Rate Estimation

abstract:
  In this paper we describe an algorithm for predicting the websites at risk in
a long range hacking activity, while jointly inferring the provenance and
evolution of vulnerabilities on websites over continuous time. Specifically, we
use hazard regression with a time-varying additive hazard function
parameterized in a generalized linear form. The activation coefficients on each
feature are continuous-time functions constrained with total variation penalty
inspired by hacking campaigns. We show that the optimal solution is a 0th order
spline with a finite number of adaptively chosen knots, and can be solved
efficiently. Experiments on real data show that our method significantly
outperforms classic methods while providing meaningful interpretability.


title: On the quantized dynamics of factorial languages

abstract:
  We study local piecewise conjugacy of the quantized dynamics arising from
factorial languages. We show that it induces a bijection between allowable
words of same length and thus it preserves entropy. In the case of sofic
factorial languages we prove that local piecewise conjugacy translates to
unlabeled graph isomorphism of the follower set graphs. Moreover it induces an
unlabeled graph isomorphism between the Fischer covers of irreducible
subshifts. We verify that local piecewise conjugacy does not preserve finite
type nor irreducibility; but it preserves soficity. Moreover it implies
identification (up to a permutation) for factorial languages of type $1$ if,
and only if, the follower set function is one-to-one on the symbol set.


title: The Distribution of Optimal Strategies in Symmetric Zero-sum Games

abstract:
  Given a skew-symmetric matrix, the corresponding two-player symmetric
zero-sum game is defined as follows: one player, the row player, chooses a row
and the other player, the column player, chooses a column. The payoff of the
row player is given by the corresponding matrix entry, the column player
receives the negative of the row player. A randomized strategy is optimal if it
guarantees an expected payoff of at least 0 for a player independently of the
strategy of the other player. We determine the probability that an optimal
strategy randomizes over a given set of actions when the game is drawn from a
distribution that satisfies certain regularity conditions. The regularity
conditions are quite general and apply to a wide range of natural
distributions.


title: A remark on the paper "Redundancy of multiset topological spaces"

abstract:
  In this note the authors have raised the question regarding the validity of
the main result in [1] by setting an example.


title:
Explicit and Exact Traveling Wave Solutions of Cahn Allen equation using
  MSE Method

abstract:
  By using Modified simple equation method, we study the Cahn Allen equation
which arises in many scientific applications such as mathematical biology,
quantum mechanics and plasma physics. As a result, the existence of solitary
wave solutions of the Cahn Allen equation is obtained. Exact explicit solutions
interms of hyperbolic solutions of the associated Cahn Allen equation are
characterized with some free parameters. Finally, the variety of structure and
graphical representation make the dynamics of the equations visible and
provides the mathematical foundation in mathematical biology, quantum mechanics
and plasma physics.


title: The Hughes model for pedestrian dynamics and congestion modelling

abstract:
  In this paper we present a numerical study of some variations of the Hughes
model for pedestrian flow under different types of congestion effects. The
general model consists of a coupled non-linear PDE system involving an eikonal
equation and a first order conservation law, and it intends to approximate the
flow of a large pedestrian group aiming to reach a target as fast as possible,
while taking into account the congestion of the crowd.
  We propose an efficient semi-Lagrangian scheme (SL) to approximate the
solution of the PDE system and we investigate the macroscopic effects of
different penalization functions modelling the congestion phenomena.


title: A Log PSS morphism with applications to Lagrangian embeddings

abstract:
  Let $M$ be a smooth projective variety and $\mathbf{D}$ an ample normal
crossings divisor. From topological data associated to the pair $(M,
\mathbf{D})$, we construct, under assumptions on Gromov-Witten invariants, a
series of distinguished classes in symplectic cohomology of the complement $X =
M \backslash \mathbf{D}$. Under further "topological" assumptions on the pair,
these classes can be organized into a Log(arithmic) PSS morphism, from a vector
space which we term the logarithmic cohomology of $(M, \mathbf{D})$ to
symplectic cohomology. Turning to applications, we show that these methods and
some knowledge of Gromov-Witten invariants can be used to produce dilations and
quasi-dilations (in the sense of Seidel-Solomon [SS]) in examples such as conic
bundles. In turn, the existence of such elements imposes strong restrictions on
exact Lagrangian embeddings, especially in dimension 3. For instance, we prove
that any exact Lagrangian in a complex 3-dimensional conic bundle over
$(\mathbb{C}^*)^2$ must be diffeomorphic to $T^3$ or a connect sum $\#^n S^1
\times S^2$.


title: Hyperbolic valued random variables and conditional expectation

abstract:
  In this paper, we introduce the concept of hyperbolic valued random
variables, their expectation and moments. We develop the hyperbolic analogue of
Binomial and Poisson distributions. We study some of the properties of
expectation on the basis of decomposition of a hyperbolic number into
idempotent components. Finally we define conditional expectation of hyperbolic
valued random variable and study some of its basic properties. Our random
variable can take values which are zero divisors and this is the important part
of this study.


title:
Item response models for the longitudinal analysis of health-related
  quality of life in cancer clinical trials

abstract:
  Statistical research regarding health-related quality of life (HRQoL) is a
major challenge to better evaluate the impact of the treatments on their
everyday life and to improve patients' care. Among the models that are used for
the longitudinal analysis of HRQoL, we focused on the mixed models from the
item response theory to analyze directly the raw data from questionnaires.
Using a recent classification of generalized linear models for categorical
data, we discussed about a conceptual selection of these models for the
longitudinal analysis of HRQoL in cancer clinical trials. Through
methodological and practical arguments, the adjacent and cumulative models seem
particularly suitable for this {context}. Specially in cancer clinical trials
and for the comparison between two groups, the cumulative models has the
advantage of providing intuitive illustrations of results. To complete the
comparison studies already performed in literature, a simulation study based on
random part of the mixed models is then carried out to compare the linear mixed
model classically used to the discussed item response models. As expected, the
sensitivity of item response models to detect random effect with lower variance
is better than the linear mixed model sensitivity. Finally, a longitudinal
analysis of HRQoL data from cancer clinical trial is carried out using an item
response cumulative model.


title: Projective Space: Points and Planes

abstract:
  We take points and planes as fundamental, lines as derived, in an axiomatic
formulation of three-dimensional projective space, the self-dual nature of
which formulation renders automatic the principle of duality.


title:
Symbolic Iterative Solution of Boundary Value Problems for Partial
  Differential Equations

abstract:
  In this article we introduce a simple straightforward and powerful method
involving symbolic manipulation, Picard iteration, and auxiliary variables for
approximating solutions of partial differential boundary value problems. The
method is easy to implement, computationally efficient, and it is highly
accurate. The output of the method is a function that approximates the exact
solution.


title:
Effect of Weak Disorder on the BCS-BEC crossover in a two-dimensional
  Fermi Gas

abstract:
  In this article we study the two-dimensional (2D) ultracold Fermi gas with
weak impurity in the framework of mean-field theory where the impurity is
introduced through Gaussian fluctuations. We have investigated the role of the
impurity by studying the experimentally accessible quantities such as
condensate fraction and equation of state of the ultracold systems. Our
analysis reveals that, at the crossover the disorder enhances superfluidity,
which we attribute to the unique nature of the unitary region and to the
dimensional effect.


title:
Novel 122-type Ir-based superconductors BaIr2Mi2 (Mi = P and As): A
  density functional study

abstract:
  We explore the structural, electronic, bonding, mechanical, thermodynamic and
superconducting properties of two newly discovered isostructural bulk
superconductors barium iridium phosphide BaIr2P2 (Tc ~ 2.1 K) and barium
iridium arsenide BaIr2As2 (Tc ~ 2.45 K). The optimized structural parameters of
both the compounds show good agreement with the experimentally evaluated
values. The replacement of P by As mostly affects the c value, whereas a
remains approximately the same. Metallic conductivity is observed for both the
superconductors. The analysis of DOS, Mulliken atomic populations and total
charge density revel a complex bonding in BaIr2P2 and BaIr2As2 with ionic,
covalent and metallic characteristics. Mechanical and dynamical stability of
both the phases is confirmed by analyzing the elastic constant data.


title:
Engines with ideal efficiency and nonzero power for sublinear transport
  laws

abstract:
  It is known that an engine with ideal efficiency ($\eta =1$ for a chemical
engine and $e = e_{\rm Carnot}$ for a thermal one) has zero power because a
reversible cycle takes an infinite time. However, at least from a theoretical
point of view, it is possible to conceive (irreversible) engines with nonzero
power that can reach ideal efficiency. Here this is achieved by replacing the
usual linear transport law by a sublinear one and taking the step-function
limit for the particle current (chemical engine) or heat current (thermal
engine) versus the applied force. It is shown that in taking this limit exact
thermodynamic inequalities relating the currents to the entropy production are
not violated.


title: On the network analysis of the state space of discrete dynamical systems

abstract:
  This paper discusses the letter entitled "Network analysis of the state space
of discrete dynamical systems" by A. Shreim et al. [Physical Review Letters,
98, 198701 (2007)]. We found that some theoretical analyses are wrong and the
proposed indicators based on two parameters of the state-mapping network cannot
discriminate the dynamical complexity of the discrete dynamical systems
composed of a 1-D Cellular Automata.


title:
What Do We Elect Committees For? A Voting Committee Model for
  Multi-Winner Rules

abstract:
  We present a new model that describes the process of electing a group of
representatives (e.g., a parliament) for a group of voters. In this model,
called the voting committee model, the elected group of representatives runs a
number of ballots to make final decisions regarding various issues. The
satisfaction of voters comes from the final decisions made by the elected
committee. Our results suggest that depending on a decision system used by the
committee to make these final decisions, different multi-winner election rules
are most suitable for electing the committee. Furthermore, we show that if we
allow not only a committee, but also an election rule used to make final
decisions, to depend on the voters' preferences, we can obtain an even better
representation of the voters.


title:
Two-photon interference from remote deterministic quantum dot
  microlenses

abstract:
  We report on two-photon interference (TPI) experiments using remote
deterministic single-photon sources. Employing 3D in-situ electron-beam
lithography, we fabricate quantum-light sources at specific target wavelengths
by integrating pre-selected semiconductor quantum dots within monolithic
microlenses. The individual single-photon sources show TPI visibilities of 49%
and 22%, respectively, under pulsed p-shell excitation at 80 MHz. For the
mutual TPI of the remote sources, we observe an uncorrected visibility of 29%,
in quantitative agreement with the pure dephasing of the individual sources.
Due to its efficient photon extraction within a broad spectral range (> 20 nm),
our microlens-based approach is predestinated for future entanglement swapping
experiments utilizing entangled photon pairs emitted by distant
biexciton-exciton radiative cascades.


title: Topological Materials Discovery using Electron Filling Constraints

abstract:
  Nodal semimetals, materials systems with nodal-point or -line Fermi surfaces,
are much sought after for their novel transport and topological properties.
Identification of experimental materials candidates, however, has mainly relied
on exhaustive database searches. Here we show how recent studies on the
interplay between electron filling and nonsymmorphic space-group symmetries can
guide the search for nodal semimetals which are `filling-enforced'. We recast
the previously-derived constraints on the allowed electron fillings for band
insulators in the 230 space groups into a new form, which enables effective
screening of materials candidates based solely on their (1) space group, (2)
electron count in the formula unit, and (3) multiplicity of the formula unit.
This criterion greatly reduces the computation load for discovering topological
materials in a database of previously-synthesized compounds. Of the more than
30,000 entires listed in a few selected nonsymmorphic space groups, our filling
criterion alone eliminates 96% of the entries before they are passed on for
further analysis. From this guided search, we discover a handful of candidates,
including the monoclinic crystals Ca$_2$Pt$_2$Ga, AgF$_2$, and Ca$_2$InOsO$_6$,
and the orthorhombic crystal CsHg$_2$. Based on ab initio calculations, we show
that these materials have filling-enforced Dirac nodes near the Fermi energy.
In addition, we also identify CaPtGa as a promising filling-enforced Dirac-ring
semimetal candidate.


title:
An extensions of Kannappan's and Van Vleck's functional equations on
  semigroups

abstract:
  This paper treats two functional equations, the Kannppan-Van Vleck functional
equation $$\mu(y)f(x\tau(y)z_0)\pm f(xyz_0) =2f(x)f(y), \;x,y\in S$$ and the
following variant of it
  $$\mu(y)f(\tau(y)xz_0)\pm f(xyz_0) = 2f(x)f(y), \;x,y\in S,$$ in the setting
of semigroups $S$ that need not be abelian or unital, $\tau$ is an involutive
morphism of $S$, $\mu$ : $S\longrightarrow \mathbb{C}$ is a multiplicative
function such that $\mu(x\tau(x))=1$ for all $x\in S$ and $z_0$ is a fixed
element in the center of $S$. We find the complex-valued solutions of these
equations in terms of multiplicative functions and solutions of d'Alembert's
functional equation.


title: Thermal tomography with unknown boundary

abstract:
  Thermal tomography is an imaging technique for deducing information about the
internal structure of a physical body from temperature measurements on its
boundary. This work considers time-dependent thermal tomography modeled by a
parabolic initial/boundary value problem without accurate information on the
exterior shape of the examined object. The adaptive sparse pseudospectral
approximation method is used to form a polynomial surrogate for the dependence
of the temperature measurements on the thermal conductivity, the heat capacity,
the boundary heat transfer coefficient and the body shape. These quantities can
then be efficiently reconstructed via nonlinear, regularized least squares
minimization employing the surrogate and its derivatives. The functionality of
the resulting reconstruction algorithm is demonstrated by numerical experiments
based on simulated data in two spatial dimensions.


title: Probabilistic structure discovery in time series data

abstract:
  Existing methods for structure discovery in time series data construct
interpretable, compositional kernels for Gaussian process regression models.
While the learned Gaussian process model provides posterior mean and variance
estimates, typically the structure is learned via a greedy optimization
procedure. This restricts the space of possible solutions and leads to
over-confident uncertainty estimates. We introduce a fully Bayesian approach,
inferring a full posterior over structures, which more reliably captures the
uncertainty of the model.


title: Population Protocols with Faulty Interactions: the Impact of a Leader

abstract:
  We consider the problem of simulating traditional population protocols under
weaker models of communication, which include one-way interactions (as opposed
to two-way interactions) and omission faults (i.e., failure by an agent to read
its partner's state during an interaction), which in turn may be detectable or
undetectable. We focus on the impact of a leader, and we give a complete
characterization of the models in which the presence of a unique leader in the
system allows the construction of simulators: when simulations are possible, we
give explicit protocols; when they are not, we give proofs of impossibility.
Specifically, if each agent has only a finite amount of memory, the simulation
is possible only if there are no omission faults. If agents have an unbounded
amount of memory, the simulation is possible as long as omissions are
detectable. If an upper bound on the number of omissions involving the leader
is known, the simulation is always possible, except in the one-way model in
which one side is unable to detect the interaction.


title: A note on the automorphism group of a compact complex manifold

abstract:
  In this note, we give explicit examples of compact complex 3-folds which
admit automorphisms that are isotopic to the identity through C
$\infty$-diffeomorphisms but not through biholomorphisms. These automorphisms
play an important role in the construction of the Te-ichm{\"u}ller stack of
higher dimensional manifolds.


title:
Stability Satisfied Numerical Approximates to the Non-analytical
  Solutions of the Cubic Schr\"odinger Equation

abstract:
  The time dependent complex Schr\"odinger equation with cubic nonlinearity is
solved by constructing differential quadrature algorithm based on sinc
functions. Reduction to a coupled system of real equations enables to approach
the space derivative terms by the proposed method. The resulted ordinary
differential equation system is integrated with respect to the time variable by
using a bunch explicit methods of lower and higher orders. Some initial
boundary value problems containing some analytical and non-analytical initial
data are solved for experimental illustrations. The computational errors
between the analytical and numerical solutions are measured by the discrete
maximum error norm in case the analytical solution exists. The two conserved
quantities are calculated by using the numerical results in all cases. The
matrix stability analysis is implemented to control the time step size.


title:
Computer modeling of exponential and logarithmic functions of
  generalized quaternions in symbolic computation system

abstract:
  The paper deals with the process of mathematical modeling representations of
exponential and logarithmic functions hypercomplex number system of generalized
quaternions via determining a linear differential equation with hypercomplex
coefficients. Simulation is performed using symbolic computation system Maple.
Some properties of these concepts and their relation to the exponential
representations of specific non-commutative hypercomplex number systems of
dimension four.


title:
High-Frequency Modeling and Simulation of a Single-Phase Three-Winding
  Transformer Including Taps in Regulating Winding

abstract:
  Transformer terminal equivalents obtained via admittance measurements are
suitable for simulating high-frequency transient interaction between the
transformer and the network. This paper augments the terminal equivalent
approach with a measurement-based voltage transfer function model which permits
calculation of voltages at internal points in the regulating winding. The
approach is demonstrated for a single-phase three-winding transformer in tap
position Nom+ with inclusion of three internal points in the regulating winding
that represent the mid-point and the two extreme ends. The terminal equivalent
modeling makes use of additional common-mode measurements to avoid error
magnifications to result from the ungrounded tertiary winding. The final model
is used in a time domain simulation where ground-fault initiation results in a
resonant voltage build-up in the winding. It is shown that that the peak value
of the resonant overvoltage can be higher than during the lightning impulse
test, with unfavorable network conditions. Additional measurements show that
the selected tap position affects the terminal behavior of the transformer,
changing the frequency and peak value of the lower resonance point in the
voltage transfer between windings.


title:
Hedgehog Skyrmion Bubbles in Ultrathin Films with Interfacial
  Dzyaloshinskii-Moriya Interactions

abstract:
  Collective spin ensembles known as skyrmion bubbles can exist in ultrathin
magnetic film heterostructures and promise miniscule diameters and low-power
all-electrical manipulation. The nucleation, identification and manipulation of
skyrmions is of great interest, in part, because of their non-trivial topology.
Here we ascertain the topology of 100 nm isolated hedgehog skyrmion bubbles and
probe their response to external fields at room temperature in [ Pt \ Co (0.8
nm) \ Ir ] films. We find that structural disorder can stabilize skyrmion
bubble states which exhibit creep-like domain wall motion. This makes the
extraction of DMI from observations difficult and could explain the larger than
predicted bubble sizes observed in interfacial DMI films. Intriguingly, we
report on a critical size for hedgehog skyrmions, above which the bubbles lose
circular symmetry and take up an irregular shape. Combining Lorentz TEM and
fully three dimensional multi-layered simulations, we demonstrate the unique
behavior of these topologically non-trivial spin textures.


title: Some contributions to Regular Polygons

abstract:
  The aim of this work is to use Napoleon's Theorem in different regular
polygons, and decide whether we can prove Napoleon's Theorem is only limited
with triangles or it could be done in other regular polygons that can create
regular polygons.


title: Strongly correlated Bose gases

abstract:
  The strongly interacting Bose gas is one of the most fundamental paradigms of
quantum many-body physics and the subject of many experimental and theoretical
investigations. We review recent progress on strongly correlated Bose gases,
starting with a description of beyond mean-field corrections. We show that the
Efimov effect leads to non universal phenomena and to a metastability of the
low temperature Bose gas through three-body recombination to deeply bound
molecular states. We outline differences and similarities with ultracold Fermi
gases, discuss recent experiments on the unitary Bose gas, and finally present
a few perspectives for future research.


title:
An elementary proof of the positivity of the intertwining operator in
  one-dimensional trigonometric Dunkl theory

abstract:
  This note is devoted to the intertwining operator in the one--dimensional
trigonometric Dunkl setting. We obtain a simple integral expression of this
operator and deduce its positivity.


title:
A fully objective Bayesian approach for the Behrens-Fisher problem using
  historical studies

abstract:
  For in vivo research experiments with small sample sizes and available
historical data, we propose a sequential Bayesian method for the Behrens-Fisher
problem. We consider it as a model choice question with two models in
competition: one for which the two expectations are equal and one for which
they are different. The choice between the two models is performed through a
Bayesian analysis, based on a robust choice of combined objective and
subjective priors, set on the parameters space and on the models space. Three
steps are necessary to evaluate the posterior probability of each model using
two historical datasets similar to the one of interest. Starting from the
Jeffreys prior, a posterior using a first historical dataset is deduced and
allows to calibrate the Normal-Gamma informative priors for the second
historical dataset analysis, in addition to a uniform prior on the model space.
From this second step, a new posterior on the parameter space and the models
space can be used as the objective informative prior for the last Bayesian
analysis. Bayesian and frequentist methods have been compared on simulated and
real data. In accordance with FDA recommendations, control of type I and type
II error rates has been evaluated. The proposed method controls them even if
the historical experiments are not completely similar to the one of interest.


title: Langevin Incremental Mixture Importance Sampling

abstract:
  This work proposes a novel method through which local information about the
target density can be used to construct an efficient importance sampler. The
backbone of the proposed method is the Incremental Mixture Importance Sampling
(IMIS) algorithm of Raftery and Bao (2010), which builds a mixture importance
distribution incrementally, by positioning new mixture components where the
importance density lacks mass, relative to the target. The key innovation
proposed here is that the mixture components used by IMIS are local
approximations to the target density. In particular, their mean vectors and
covariance matrices are constructed by numerically solving certain differential
equations, whose solution depends on the gradient field of the target
log-density. The new sampler has a number of advantages: a) it provides an
extremely parsimonious parametrization of the mixture importance density, whose
configuration effectively depends only on the shape of the target and on a
single free parameter representing pseudo-time; b) it scales well with the
dimensionality of the target; c) it can deal with targets that are not log-
concave. The performance of the proposed approach is demonstrated on a
synthetic non-Gaussian multimodal density, defined on up to eighty dimensions,
and on a Bayesian logistic regression model, using the Sonar data-set. The
Julia code implementing the importance sampler proposed here can be found at
https:/github.com/mfasiolo/LIMIS.


title: Throughput analysis in networks of WLANs

abstract:
  This paper proposes a simple but accurate approximation to analytically model
both the inter-WLANs (Wireless Local Area Networks) interactions and the
negative effect of collisions in networks of IEEE 802.11 WLANs. Inter-WLANs
interactions are characterized using a continuous time Markov chain (CTMC)
model where states represent the set of active WLANs at a given time. Then, the
effect of collisions is considered by analyzing the local dynamics between
contending WLANs at every state using the well-known IEEE 802.11 Bianchi model.
Results confirm the accuracy of the presented approach.


title:
Validity of Chemical Equilibrium Approach in the Study of Kinetic
  Freeze-out in p-Pb Collisions at LHC

abstract:
  Transverse momentum spectra of identified pions, Kaons , protons and Lambdas
produced at mid-rapidity (0 < ycm < 0.5) in p-Pb collisions at root(sNN) = 5.02
TeV is studied for different collision centralities by using a Unified
Statistical Thermal Freeze-out Model (USTFM). A fairly good agreement is seen
between the calculated results and the experimental data points taken from the
ALICE experiment. Kinetic freeze-out conditions are extracted from the fits of
the transverse momentum spectra of these hadrons for each centrality class. A
comparison of the obtained freeze-out parameters with those of heavy-ion
collisions (Pb + Pb) is made and discussed.


title: A counterexample to Feit's Problem VIII on decomposition numbers

abstract:
  We find a counterexample to Feit's Problem VIII on the bound of decomposition
numbers. This also answers a question raised by T. Holm and W. Willems.


title: SANet: Structure-Aware Network for Visual Tracking

abstract:
  Convolutional neural network (CNN) has drawn increasing interest in visual
tracking owing to its powerfulness in feature extraction. Most existing
CNN-based trackers treat tracking as a classification problem. However, these
trackers are sensitive to similar distractors because their CNN models mainly
focus on inter-class classification. To address this problem, we use
self-structure information of object to distinguish it from distractors.
Specifically, we utilize recurrent neural network (RNN) to model object
structure, and incorporate it into CNN to improve its robustness to similar
distractors. Considering that convolutional layers in different levels
characterize the object from different perspectives, we use multiple RNNs to
model object structure in different levels respectively. Extensive experiments
on three benchmarks, OTB100, TC-128 and VOT2015, show that the proposed
algorithm outperforms other methods. Code is released at
http://www.dabi.temple.edu/~hbling/code/SANet/SANet.html.


title: Central limit theorems for biased randomly trapped random walks on Z

abstract:
  We prove CLTs for biased randomly trapped random walks in one dimension. In
particular, we will establish an annealed invariance principal by considering a
sequence of regeneration times under the assumption that the trapping times
have finite second moment. In a quenched environment, an environment dependent
centring is determined which is necessary to achieve a central limit theorem.
As our main motivation, we apply these results to biased walks on subcritical
Galton-Watson trees conditioned to survive and prove a tight bound on the bias
required to obtain such limiting behaviour.


title:
The subset-matched Jaccard index for evaluation of Segmentation for
  Plant Images

abstract:
  We describe a new measure for the evaluation of region level segmentation of
objects, as applied to evaluating the accuracy of leaf-level segmentation of
plant images. The proposed approach enforces the rule that a region (e.g. a
leaf) in either the image being evaluated or the ground truth image evaluated
against can be mapped to no more than one region in the other image. We call
this measure the subset-matched Jaccard index.


title:
Searching for metal-deficient emission-line galaxy candidates: the final
  sample of the SDSS DR12 galaxies

abstract:
  We present a spectroscopic study of metal-deficient dwarf galaxy candidates,
selected from the SDSS DR12. The oxygen abundances were derived using the
direct method in galaxies with the electron temperature-sensitive emission line
[OIII]4363A measured with an accuracy better than 30%. The oxygen abundances
for the remaining galaxies with larger uncertainties of the [OIII]4363A line
fluxes were calculated using a strong-line semi-empirical method by Izotov and
Thuan. The resulting sample consists of 287 low-metallicity candidates with
oxygen abundances below 12+logO/H=7.65 including 23 extremely metal-deficient
(XMD) candidates with 12+log O/H<7.35. Ten out of sixteen XMDs known so far (or
~60%) have been discovered by our team using the direct method. Three XMDs were
found in the present study. We study relations between global parameters of
low-metallicity galaxies, including absolute optical magnitudes, Hbeta
luminosities (or equivalently star formation rates), stellar masses,
mid-infrared colours, and oxygen abundances. Low-metallicity and XMD galaxies
strongly deviate to lower metallicities in L-Z, L(Hbeta)-Z and Mstar-Z diagrams
than in relations obtained for large samples of low-redshift, star-forming
galaxies with non-restricted metallicities. These less chemically evolved
galaxies with stellar masses ~10^6-10^8Msun, Hbeta luminosities ~10^38-10^41
erg/s, SFR~0.01-1.0Msun/yr, and sSFR~50 Gyr^-1 have physical conditions which
may be characteristic of high-redshift low-mass star-forming galaxies which are
still awaiting discovery.


title: Learning From Graph Neighborhoods Using LSTMs

abstract:
  Many prediction problems can be phrased as inferences over local
neighborhoods of graphs. The graph represents the interaction between entities,
and the neighborhood of each entity contains information that allows the
inferences or predictions. We present an approach for applying machine learning
directly to such graph neighborhoods, yielding predicitons for graph nodes on
the basis of the structure of their local neighborhood and the features of the
nodes in it. Our approach allows predictions to be learned directly from
examples, bypassing the step of creating and tuning an inference model or
summarizing the neighborhoods via a fixed set of hand-crafted features. The
approach is based on a multi-level architecture built from Long Short-Term
Memory neural nets (LSTMs); the LSTMs learn how to summarize the neighborhood
from data. We demonstrate the effectiveness of the proposed technique on a
synthetic example and on real-world data related to crowdsourced grading,
Bitcoin transactions, and Wikipedia edit reversions.


title:
Non-perturbative effects and indirect exchange interaction between
  quantum impurities on metallic (111) surfaces

abstract:
  The (111) surface of noble metals is usually treated as an isolated two
dimensional (2D) triangular lattice completely decoupled from the bulk.
However, unlike topological insulators, other bulk bands cross the Fermi level.
We here introduce an effective tight-binding model that accurately reproduces
results from first principles calculations, accounting for both surface and
bulk states. We numerically solve the many-body problem of two quantum
impurities sitting on the surface by means of the density matrix
renormalization group. By performing simulations in a star geometry, we are
able to study the non-perturbative problem in the thermodynamic limit with
machine precision accuracy. We find that there is a non-trivial competition
between Kondo and RKKY physics and as a consequence, ferromagnetism is never
developed, except at short distances. The bulk introduces a variation in the
period of the RKKY interactions, and therefore the problem departs considerably
from the simpler 2D case. In addition, screening, and the magnitude of the
effective indirect exchange is enhanced by the contributions from the bulk
states.


title: Limits on uranium and thorium bulk content in GERDA Phase I detectors

abstract:
  Internal contaminations of $^{238}$U, $^{235}$U and $^{232}$Th in the bulk of
high purity germanium detectors are potential backgrounds for experiments
searching for neutrinoless double beta decay of $^{76}$Ge. The data from GERDA
Phase~I have been analyzed for alpha events from the decay chain of these
contaminations by looking for full decay chains and for time correlations
between successive decays in the same detector. No candidate events for a full
chain have been found. Upper limits on the activities in the range of a few
nBq/kg for $^{226}$Ra, $^{227}$Ac and $^{228}$Th, the long-lived daughter
nuclides of $^{238}$U, $^{235}$U and $^{232}$Th, respectively, have been
derived. With these upper limits a background index in the energy region of
interest from $^{226}$Ra and $^{228}$Th contamination is estimated which
satisfies the prerequisites of a future ton scale germanium double beta decay
experiment.


title:
Isotropy prohibits the loss of strong ellipticity through homogenization
  in linear elasticity

abstract:
  Since the seminal contribution of Geymonat, M{\"u}ller, and Triantafyllidis,
it is known that strong ellipticity is not necessarily conserved by
homogenization in linear elasticity. This phenomenon is typically related to
microscopic buckling of the composite material. The present contribution is
concerned with the interplay between isotropy and strong ellipticity in the
framework of periodic homogenization in linear elasticity. Mixtures of two
isotropic phases may indeed lead to loss of strong ellipticity when arranged in
a laminate manner. We show that if a matrix/inclusion type mixture of isotropic
phases produces macroscopic isotropy, then strong ellipticity cannot be lost.
R{\'e}sum{\'e}. Nous savons depuis l'article fondateur de Geymonat, M{\"u}ller
et Triantafyl-lidis qu'en{\'e}lasticit{\'e}en{\'e}lasticit{\'e} lin{\'e}aire
l'homog{\'e}n{\'e}isation p{\'e}riodique ne conserve pas n{\'e}cessairement
l'ellipticit{\'e} forte. Ce ph{\'e}nom{\`e}ne est li{\'e} au flambage
microscopique des composites. Notre contribution consiste examiner le r{\^o}le
de l'isotropie dans ce type de pathologie. Le m{\'e}lange de deux phases
isotropes peut en effet conduir{\`e} a cette perte si l'arrangement est celui
d'un lamin{\'e}. Nous montrons qu'en revanche, si un arrangement de type
ma-trice/inclusion produit un tenseur homog{\'e}n{\'e}is{\'e} isotrope, alors
la forte ellipticit{\'e} est con-serv{\'e}e.


title: Cosmology with Galaxy Cluster Phase Spaces

abstract:
  We present a novel approach to constrain accelerating cosmologies with galaxy
cluster phase spaces. With the Fisher matrix formalism we forecast constraints
on the cosmological parameters that describe the cosmological expansion
history. We find that our probe has the potential of providing constraints
comparable to, or even stronger than, those from other cosmological probes.
More specifically, with 1000 (100) clusters uniformly distributed in the
redshift range $ 0 \leq z \leq 0.8$, after applying a conservative $80\%$ mass
scatter prior on each cluster and marginalizing over all other parameters, we
forecast $1\sigma$ constraints on the dark energy equation of state $w$ and
matter density parameter $\Omega_M$ of $\sigma_w = 0.138 (0.431)$ and
$\sigma_{\Omega_M} = 0.007 (0.025)$ in a flat universe. Assuming 40\% mass
scatter and adding a prior on the Hubble constant we can achieve a constraint
on the CPL parametrization of the dark energy equation of state parameters
$w_0$ and $w_a$ with 100 clusters in the same redshift range: $\sigma_{w_0} =
0.191 $ and $\sigma_{w_a} = 2.712$. Dropping the assumption of flatness and
assuming $w=-1$ we also attain competitive constraints on the matter and dark
energy density parameters: $\sigma_{\Omega_M} = 0.101$ and
$\sigma_{\Omega_{\Lambda}} = 0.197$ for 100 clusters uniformly distributed in
the range $ 0 \leq z \leq 0.8$ after applying a prior on the Hubble constant.
We also discuss various observational strategies for tightening constraints in
both the near and far future.


title: A Three Doublet Lepton-Specific Model

abstract:
  In the lepton-specific version of two Higgs doublet models, a discrete
symmetry is used to couple one Higgs, $\Phi_2$, to quarks and the other,
$\Phi_1$, to leptons. The symmetry eliminates tree level flavor changing
neutral currents (FCNC). Motivated by strong constraints on such currents in
the quark sector from meson-antimeson mixing, and by hints of $h \to \mu\tau$
in the lepton sector, we study a simple three Higgs doublet model in which one
doublet couples to quarks and the other two to leptons. Unlike most other
studies of three Higgs doublet models, we impose no flavor symmetry and just
use a $Z_2$ symmetry to constrain the Yukawa couplings. We present the model
and discuss the various mixing angles. Constraining the parameters to be
consistent with observations of the Higgs boson at the LHC, we study the
properties of the charged Higgs boson(s) in the model, focusing on the case in
which the charged Higgs is above the top threshold. It is found that one can
have the branching fraction of the charged Higgs into $\tau\nu_\tau$ comparable
to $t\bar{b}$ decay without needing very large values for the ratios of vevs.
One can also get a large branching fraction for the much more easily observable
$\mu\nu_\tau$ decay.


title:
Approximate solution for the oscillation death state in pulse coupled
  oscillators

abstract:
  We study numerically the oscillation death state in the phase oscillator
model proposed byWinfree. We found that the phases in this state follow very
simple rules, actually, besides intrinsic properties of the oscillators, such
as natural frequency and pulse shape, they depend only on the inverse of the
degree. Other topological properties such as transitivity or associativity
seems to play no role on this state. Furthermore, we found that
degree-frequency correlation helps to inhibit oscillation death. Simple
analytical approximations corroborate the numerical results.


title:
CMOS based image cytometry for detection of phytoplankton in ballast
  water

abstract:
  We introduce an image cytometer (I-CYT) for the analysis of phytoplankton in
fresh and marine water environments. A linear quantification of cell numbers
was observed covering several orders of magnitude using cultures of Tetraselmis
and Nannochloropsis measured by autofluorescence in a laboratory environment.
We assessed the functionality of the system outside the laboratory by
phytoplankton quantification of samples taken from a marine water environment
(Dutch Wadden Sea, The Netherlands) and a fresh water environment (Lake Ijssel,
The Netherlands). The I-CYT was also employed to study the effects of two
ballast water treatment systems (BWTS), based on chlorine electrolysis and UV
sterilization, with the analysis including the vitality of the phytoplankton.
For comparative study and benchmarking of the I-CYT, a standard flow cytometer
was used. Our results prove a limit of detection (LOD) of 10 cells/ml with an
accuracy between 0.7 and 0.5 log, and a correlation of 88.29% in quantification
and 96.21% in vitality, with respect to the flow cytometry results.


title:
$\beta$-particle energy-summing correction for $\beta$-delayed proton
  emission measurements

abstract:
  A common approach to studying $\beta$-delayed proton emission is to measure
the energy of the emitted proton and corresponding nuclear recoil in a
double-sided silicon-strip detector (DSSD) after implanting the $\beta$-delayed
proton emitting ($\beta$p) nucleus. However, in order to extract the
proton-decay energy, the measured energy must be corrected for the additional
energy implanted in the DSSD by the $\beta$-particle emitted from the $\beta$p
nucleus, an effect referred to here as $\beta$-summing. We present an approach
to determine an accurate correction for $\beta$-summing. Our method relies on
the determination of the mean implantation depth of the $\beta$p nucleus within
the DSSD by analyzing the shape of the total (proton + recoil + $\beta$) decay
energy distribution shape. We validate this approach with other mean
implantation depth measurement techniques that take advantage of energy
deposition within DSSDs upstream and downstream of the implantation DSSD.


title:
Wigner's representation of quantum mechanics in integral form and its
  applications

abstract:
  We consider quantum phase-space dynamics using Wigner's representation of
quantum mechanics. We stress the usefulness of the integral form for the
description of Wigner's phase-space current~$\bm J$ as an alternative to the
popular Moyal bracket. The integral form brings out the symmetries between
momentum and position representations of quantum mechanics, is numerically
stable, and allows us to perform some calculations using elementary integrals
instead of Groenewold star products. Our central result is an explicit,
elementary proof which shows that only systems up to quadratic in their
potential fulfill Liouville's theorem of volume preservation in quantum
mechanics. Contrary to a recent suggestion, our proof shows that the
non-Liouvillian character of quantum phase-space dynamics cannot be transformed
away.


title: Bidiagonalization with Parallel Tiled Algorithms

abstract:
  We consider algorithms for going from a "full" matrix to a condensed "band
bidiagonal" form using orthogonal transformations. We use the framework of
"algorithms by tiles". Within this framework, we study: (i) the tiled
bidiagonalization algorithm BiDiag, which is a tiled version of the standard
scalar bidiagonalization algorithm; and (ii) the R-bidiagonalization algorithm
R-BiDiag, which is a tiled version of the algorithm which consists in first
performing the QR factorization of the initial matrix, then performing the
band-bidiagonalization of the R-factor. For both bidiagonalization algorithms
BiDiag and R-BiDiag, we use four main types of reduction trees, namely FlatTS,
FlatTT, Greedy, and a newly introduced auto-adaptive tree, Auto. We provide a
study of critical path lengths for these tiled algorithms, which shows that (i)
R-BiDiag has a shorter critical path length than BiDiag for tall and skinny
matrices, and (ii) Greedy based schemes are much better than earlier proposed
variants with unbounded resources. We provide experiments on a single multicore
node, and on a few multicore nodes of a parallel distributed shared-memory
system, to show the superiority of the new algorithms on a variety of matrix
sizes, matrix shapes and core counts.


title:
A statistical model for brain networks inferred from large-scale
  electrophysiological signals

abstract:
  Network science has been extensively developed to characterize structural
properties of complex systems, including brain networks inferred from
neuroimaging data. As a result of the inference process, networks estimated
from experimentally obtained biological data, represent one instance of a
larger number of realizations with similar intrinsic topology. A modeling
approach is therefore needed to support statistical inference on the bottom-up
local connectivity mechanisms influencing the formation of the estimated brain
networks. We adopted a statistical model based on exponential random graphs
(ERGM) to reproduce brain networks, or connectomes, estimated by spectral
coherence between high-density electroencephalographic (EEG) signals. We
validated this approach in a dataset of 108 healthy subjects during eyes-open
(EO) and eyes-closed (EC) resting-state conditions. Results showed that the
tendency to form triangles and stars, reflecting clustering and node
centrality, better explained the global properties of the EEG connectomes as
compared to other combinations of graph metrics. Synthetic networks generated
by this model configuration replicated the characteristic differences found in
brain networks, with EO eliciting significantly higher segregation in the alpha
frequency band (8-13 Hz) as compared to EC. Furthermore, the fitted ERGM
parameter values provided complementary information showing that clustering
connections are significantly more represented from EC to EO in the alpha
range, but also in the beta band (14-29 Hz), which is known to play a crucial
role in cortical processing of visual input and externally oriented attention.
These findings support the current view of the brain functional segregation and
integration in terms of modules and hubs, and provide a statistical approach to
extract new information on the (re)organizational mechanisms in healthy and
diseased brains.


title:
Synthetic SXR diagnostic using GEM detectors on WEST: development in the
  prospect of tungsten monitoring

abstract:
  WEST (Tungsten Environment in Steady-State Tokamak) will be operating by the
end of 2016 as a test bed for the ITER divertor components in long pulse
operation. In this context, radiative cooling of highly ionized impurities like
tungsten (W) sputtered from Plasma Facing Components (PFC) into the plasma core
is a critical issue since even small impurity concentrations below 10-4 degrade
significantly plasma performances and can lead to radiative collapse. In the
plasma core, tungsten emission is dominant in the Soft X-ray (SXR) range 0.1
keV -- 15 keV with complex contributions from line transition, radiative
recombination and Bremsstrahlung emission.This paper presents the recent
development of a synthetic SXR diagnostic using GEM (Gas Electron Multiplier)
detectors. This diagnostic will be used on WEST for W transport studies and
will be equipped with two new GEM based poloidal cameras allowing 2D
tomographic reconstructions with spectral resolution in energy bands. Thus once
GEM response to plasma emissivity is characterized thanks to synthetic
diagnostic, it offers new possibilities to disentangle the different SXR
contributions in harsh fusion environments like e.g. WEST or ITER with respect
to conventional semiconductor diodes working in current mode. Emitted SXR
spectrum from the plasma is modelled thanks to ADAS database from given WEST
scenario. The synthetic diagnostic includes Lines of Sight (LoS) etendues of
the two cameras as well as probability of photoabsorption through filters,
photoionization in the detection gas mixture (Ar-CO2), and transport of
electron avalanches in the gas through GEM foils as computed with Magboltz.
Local SXR emissivity is then retrieved from tomographic inversion using a
Minimum Fisher Information (MFI) algorithm.


title:
Dislocation contrast in cathodoluminescence and electron-beam induced
  current maps on GaN(0001)

abstract:
  We theoretically analyze the contrast observed at the outcrop of a threading
dislocation at the GaN(0001) surface in cathodoluminescence and electron-beam
induced current maps. We consider exciton diffusion and recombination including
finite recombination velocities both at the planar surface and at the
dislocation. Formulating the reciprocity theorem for this general case enables
us to provide a rigorous analytical solution of this diffusion-recombination
problem. The results of the calculations are applied to an experimental example
to determine both the exciton diffusion length and the recombination strength
of threading dislocations in a free-standing GaN layer with a dislocation
density of $6\times10^{5}$~cm$^{-2}$.


title: Infinitesimal Automorphisms of VB-groupoids and algebroids

abstract:
  VB-groupoids and algebroids are vector bundle objects in the categories of
Lie groupoids and Lie algebroids respectively, and they are related via the Lie
functor. VB-groupoids and algebroids play a prominent role in Poisson and
related geometries. Additionally, they can be seen as models for vector bundles
over singular spaces. In this paper we study their infinitesimal automorphisms,
i.e. vector fields on them generating a flow by diffeomorphisms preserving both
the linear and the groupoid/algebroid structures. For a special class of
VB-groupoids/algebroids coming from representations of Lie
groupoids/algebroids, we prove that infinitesimal automorphisms are the same as
multiplicative sections of a certain derivation groupoid/algebroid.


title:
Decoupling light and matter: permanent dipole moment induced collapse of
  Rabi oscillations

abstract:
  Rabi oscillations is a key phenomenon among the variety of quantum optical
effects that manifests itself in the periodic oscillations of a two-level
system between the ground and excited states when interacting with
electromagnetic field. Commonly, the rate of these oscillations scales
proportionally with the magnitude of the electric field probed by the two-level
system. Here, we investigate the interaction of light with a two-level quantum
emitter possessing permanent dipole moments. The semi-classical approach to
this problem predicts slowing down and even full suppression of Rabi
oscillations due to asymmetry in diagonal components of the dipole moment
operator of the two-level system. We consider behavior of the system in the
fully quantized picture and establish the analytical condition of Rabi
oscillations collapse. These results for the first time emphasize the behavior
of two-level systems with permanent dipole moments in the few photon regime,
and suggest observation of novel quantum optical effects.


title: Controlling a nuclear spin in a nanodiamond

abstract:
  The sensing capability of a single optically bright electronic spin in
diamond can be enhanced by making use of proximal dark nuclei as ancillary
spins. Such systems, so far only realized in bulk diamond, provide orders of
magnitude higher sensitivity and spectral resolution in the case of magnetic
sensing, as well as improved readout fidelity and state storage time in quantum
information schemes. In nanodiamonds, which offer additional opportunities as
mobile nanoscale sensors, electronic-nuclear spin complexes have remained
inaccessible. We demonstrate coherent control of a 13C nuclear spin located
4{\AA} from a nitrogen-vacancy center in a nanodiamond and show quantum-state
transfer between the two components of this hybrid spin system. We extract a
nuclear-spin free precession time of T2* = 26 us, which exceeds the bare
electron free precession time in nanodiamond by two orders of magnitude.


title: Kernels of L-functions and shifted convolutions

abstract:
  We give a characterisation of the field into which quotients of values of
L-functions associated to a cusp form belong. The construction involves shifted
convolution series of divisor sums and to establish it we combine parts of F.
Brown's technique to study multiple modular values with the properties of a
double Eisentein series previously studied by the author and C. O'Sullivan.


title: The involution width of finite simple groups

abstract:
  For a finite group generated by involutions, the involution width is defined
to be the minimal $k\in\mathbb{N}$ such that any group element can be written
as a product of at most $k$ involutions. We show that the involution width of
every non-abelian finite simple group is at most $4$. This result is sharp, as
there are families with involution width precisely 4.


title: Gluon momentum fraction of the nucleon from lattice QCD

abstract:
  We perform a direct calculation of the gluon momentum fraction of the nucleon
using maximally twisted mass fermion ensembles with $N_f=2+1+1$ flavors at a
pion mass of about $370\,\mathrm{MeV}$ and a lattice spacing of $a\approx
0.082\,\mathrm{fm}$ and with $N_f=2$ flavors at the physical pion mass and a
lattice spacing of $a\approx 0.093\,\mathrm{fm}$. In the definition of the
gluon operator we employ stout smearing to obtain a statistically significant
result for the bare matrix elements. In addition, we perform a lattice
perturbative calculation including 2 levels of stout smearing to carry out the
mixing and the renormalization of the quark and gluon operators. We find, after
conversion to the $\overline{\mathrm{MS}}$ scheme at a scale of
$2\,\mathrm{GeV}$: $\langle x\rangle^R_g {=} 0.284(23)(23)$ for pion mass of
about $370\,\mathrm{MeV}$ and $\langle x\rangle^R_g {=} 0.283(23)(15)$ for the
physical pion mass.