title:
Stability, convergence and Hopf bifurcation analyses of the classical
  car-following model

abstract:
  Reaction delays play an important role in determining the qualitative
dynamical properties of a platoon of vehicles traversing a straight road. In
this paper, we investigate the impact of delayed feedback on the dynamics of
the Classical Car-Following Model (CCFM). Specifically, we analyze the CCFM in
no delay, small delay and arbitrary delay regimes. First, we derive a
sufficient condition for local stability of the CCFM in no-delay and
small-delay regimes using. Next, we derive the necessary and sufficient
condition for local stability of the CCFM for an arbitrary delay. We then
demonstrate that the transition of traffic flow from the locally stable to the
unstable regime occurs via a Hopf bifurcation, thus resulting in limit cycles
in system dynamics. Physically, these limit cycles manifest as back-propagating
congestion waves on highways. In the context of human-driven vehicles, our work
provides phenomenological insight into the impact of reaction delays on the
emergence and evolution of traffic congestion. In the context of self-driven
vehicles, our work has the potential to provide design guidelines for control
algorithms running in self-driven cars to avoid undesirable phenomena.
Specifically, designing control algorithms that avoid jerky vehicular movements
is essential. Hence, we derive the necessary and sufficient condition for
non-oscillatory convergence of the CCFM. Next, we characterize the rate of
convergence of the CCFM, and bring forth the interplay between local stability,
non-oscillatory convergence and the rate of convergence of the CCFM. Further,
to better understand the oscillations in the system dynamics, we characterize
the type of the Hopf bifurcation and the asymptotic orbital stability of the
limit cycles using Poincare normal forms and the center manifold theory. The
analysis is complemented with stability charts, bifurcation diagrams and MATLAB
simulations.


title: A Generalization of Gale's lemma

abstract:
  In this work, we present a generalization of Gale's lemma. Using this
generalization, we introduce two combinatorial sharp lower bounds for ${\rm
conid}({\rm B}_0(G))+1$ and ${\rm conid}({\rm B}(G))+2$, two famous topological
lower bounds for the chromatic number of a graph $G$.


title: Radio detection of Cosmic-Ray Air Showers and High-Energy Neutrinos

abstract:
  This review provides an introduction to the radio emission by particle
cascades, an overview on the various experiments, and explains methods for the
radio measurement of air-shower properties. Furthermore, potential applications
of the radio technique in high-energy astroparticle physics are discussed. Due
to the successful operation of digital radio experiments and due to the
improved quantitative understanding of the emission, radio detection is back on
the list of promising techniques for extensive air showers. With a threshold of
about 100 PeV radio detectors are particularly useful to study the
highest-energy galactic cosmic rays and ultra-high-energy extragalactic
particles of all types. Various antenna arrays like LOPES, CODALEMA, AERA,
LOFAR, and Tunka-Rex have shown that radio measurements can compete in
precision with other techniques, in particular for the arrival direction, the
energy, and the position of the shower maximum. The scientific potential of the
radio technique seems to be maximum in combination with particle detectors,
which increases the total accuracy for air-shower measurements. This is crucial
for a better separation of different primary particles, like gamma-ray photons,
neutrinos, or different types of nuclei. In addition to air-showers the radio
technique can be used for particle cascades in dense media. Several pioneering
experiments like ARA, ARIANNA, and ANITA are currently searching for cascades
induced by ultra-high-energy neutrinos in ice. Moreover, several future
projects aim at both, high-energy cosmic-rays and neutrinos. SKA will search
for neutrino and cosmic-ray initiated cascades in the lunar regolith and
provide unprecedented detail for air-shower measurements. Finally, radio
detectors with huge exposure like GRAND, SWORD, or EVA are being considered to
study the highest energy cosmic rays and neutrinos.


title: The structure and the number of $P_7$-free bipartite graphs

abstract:
  We show that the number of labelled $P_7$-free bipartite graphs with $n$
vertices grows as $n^{\Theta(n)}$. This resolves an open problem posed by Allen
[P. Allen, Forbidden induced bipartite graphs. J. Graph Theory 60 (2009), no.
3, 219--241.], and completes the description of speeds of monogenic classes of
bipartite graphs. Our solution is based on a new decomposition scheme of
bipartite graphs, which is of independent interest.


title: Scintillation Characterizations of Tl2LiLuCl6: Ce3+ Single Crystal

abstract:
  0.5%, 1%, 3% and 5% Ce-concentration single crystals of Tl2LiLuCl6 were grown
from the melt using two zone vertical Bridgman technique. X-ray induced
emission spectra showed Ce3+ emission between 370 nm and 540 nm wavelength
range. Energy resolution, light yield and decay time of the grown samples were
measured under {\gamma}-ray excitation at room temperature. Energy resolution
of 5.6% (FWHM) with 27,000+-2700 light yield is found for 1%Ce doped sample.
For the same dopant concentration, three decay time components are also
observed. Variation of scintillation properties is observed as a function of
dopant concentration in this material.This material will provide excellent
detection efficiency for X- and {\gamma}-rays due to its high effective
Z-number and density. It is expected that this scintillor will be a potential
detector for the medical imaging techniques.


title:
Modelling the impact of intrinsic size and luminosity correlations on
  magnification estimation

abstract:
  Spatial correlations of the observed sizes and luminosities of galaxies can
be used to estimate the magnification that arises through weak gravitational
lensing. However, the intrinsic prop- erties of galaxies can be similarly
correlated through local physical effects, and these present a possible
contamination to the weak lensing estimation. In an earlier paper (Ciarlariello
et al. 2015) we modelled the intrinsic size correlations using the halo model,
assuming the galaxy sizes reflect the mass in the associated halo. Here we
extend this work to consider galaxy magnitudes and show that these may be even
more affected by intrinsic correlations than galaxy sizes, making this a bigger
systematic for measurements of the weak lensing signal. We also quantify how
these intrinsic correlations are affected by sample selection criteria based on
sizes and magnitudes.


title: Comment to "Thomson rings in a disk"

abstract:
  We have found that the minimum energy configuration of $N=395$ charges
confined in a disk and interacting via the Coulomb potential, reported by
Cerkaski et al. in Ref.~\cite{Cerkaski15} is not a global minimum of the total
electrostatic energy. We have identified a large number of configurations with
lower energy, where defects are present close to the center of the disk; thus,
the formation of a hexagonal core and valence circular rings for the centered
configurations, predicted by the model of Ref.~\cite{Cerkaski15}, is not
supported by numerical evidence and the configurations obtained with this model
cannot be used as a guide for the numerical calculations, as claimed by the
authors.


title: Massive photons from Super and Lorentz symmetry breaking

abstract:
  In the context of Standard Model Extensions (SMEs), we analyse four general
classes of Super Symmetry (SuSy) and Lorentz Symmetry (LoSy) breaking, leading
to {observable} imprints at our energy scales. The photon dispersion relations
show a non-Maxwellian behaviour for the CPT (Charge-Parity-Time reversal
symmetry) odd and even sectors. The group velocities exhibit also a directional
dependence with respect to the breaking background vector (odd CPT) or tensor
(even CPT). In the former sector, the group velocity may decay following an
inverse squared frequency behaviour. Thus, we extract a massive and gauge
invariant Carroll-Field-Jackiw photon term in the Lagrangian and show that the
mass is proportional to the breaking vector. The latter is estimated by ground
measurements and leads to a photon mass upper limit of $10^{-19}$ eV or $2
\times 10^{-55}$ kg and thereby to a potentially measurable delay at low radio
frequencies.


title: LARES Satellite Thermal Forces and a Test of General Relativity

abstract:
  We summarize a laser-ranged satellite test of frame-dragging, a prediction of
General Relativity, and then concentrate on the estimate of thermal thrust, an
important perturbation affecting the accuracy of the test. The frame dragging
study analysed 3.5 years of data from the LARES satellite and a longer period
of time for the two LAGEOS satellites. Using the gravity field GGM05S obtained
via the Grace mission, which measures the Earth's gravitational field, the
prediction of General Relativity is confirmed with a 1-$\sigma$ formal error of
0.002, and a systematic error of 0.05. The result for the value of the frame
dragging around the Earth is $\mu$ = 0.994, compared to $\mu$ = 1 predicted by
General Relativity. The thermal force model assumes heat flow from the sun
(visual) and from Earth (IR) to the satellite core and to the fused silica
reflectors on the satellite, and reradiation into space. For a roughly current
epoch (days 1460 - 1580 after launch) we calculate an average along-track drag
of -0.50 $pm/s^{2}$.


title:
Cluster abundance in chameleon $f(R)$ gravity I: toward an accurate halo
  mass function prediction

abstract:
  We refine the mass and environment dependent spherical collapse model of
chameleon $f(R)$ gravity by calibrating a phenomenological correction inspired
by the parameterized post-Friedmann framework against high-resolution $N$-body
simulations. We employ our method to predict the corresponding modified halo
mass function, and provide fitting formulas to calculate the fractional
enhancement of the $f(R)$ halo abundance with respect to that of General
Relativity (GR) within a precision of $\lesssim 5\%$ from the results obtained
in the simulations. Similar accuracy can be achieved for the full $f(R)$ mass
function on the condition that the modeling of the reference GR abundance of
halos is accurate at the percent level. We use our fits to forecast constraints
on the additional scalar degree of freedom of the theory, finding that upper
bounds competitive with current Solar System tests are within reach of cluster
number count analyses from ongoing and upcoming surveys at much larger scales.
Importantly, the flexibility of our method allows also for this to be applied
to other scalar-tensor theories characterized by a mass and environment
dependent spherical collapse.


title:
Josephson effect in spin-singlet superconductor/ferromagnetic
  insulator/spin-triplet superconductor junctions with helical $p$-wave states

abstract:
  We study the Josephson effect in spin-singlet superconductor/helical $p$-wave
superconductor junctions with a ferromagnetic barrier using the quasiclassical
Green function method. It is found that both $\sin{\phi}$-type and
$\cos{\phi}$-type current-phase relations always exist, irrespective of the gap
symmetries in superconductors. The indispensable condition for the
$\sin{\phi}$-type and $\cos{\phi}$-type current is that the magnetization must
have a component parallel to the crystallographic $a$ or $b$ axis, which is
distinct from the case of $p$-wave superconductor described by a
$\vect{d}$-vector with a uniform direction. The relation between the condition
and the symmetries of the gap functions is analysed. We investigate in detail
the symmetries and the sign reversal of the Josephson current when the
magnetization is rotated.


title: The modified Langevin description for probes in a nonlinear medium

abstract:
  When the motion of a probe strongly disturbs the thermal equilibrium of the
solvent or bath, the nonlinear response of the latter must enter the probe's
effective evolution equation. We derive that induced stochastic dynamics using
second order response around the bath thermal equilibrium. We discuss the
nature of the new term in the evolution equation which is not longer purely
dissipative, and the appearance of a novel time-scale for the probe related to
changes in the dynamical activity of the bath. A major application for the
obtained nonlinear generalized Langevin equation is in the study of colloid
motion in a visco-elastic medium.


title:
Phase Noise Influence in Optical OFDM Systems employing RF Pilot Tone
  for Phase Noise Cancellation

abstract:
  For coherent and direct-detection Orthogonal Frequency Division Multiplexed
(OFDM) systems employing radio frequency (RF) pilot tone phase noise
cancellation the influence of laser phase noise is evaluated. Novel analytical
results for the common phase error and for the (modulation dependent) inter
carrier interference are evaluated based upon Gaussian statistics for the laser
phase noise. In the evaluation it is accounted for that the laser phase noise
is filtered in the correlation signal detection. Numerical results are
presented for OFDM systems with 4 and 16 PSK modulation, 200 OFDM bins and baud
rate of 1 GS/s. It is found that about 225 km transmission is feasible for the
coherent 4PSK-OFDM system over normal (G.652) fiber.


title:
A spectral theory for simply periodic solutions of the sinh-Gordon
  equation

abstract:
  In this work a spectral theory for 2-dimensional, simply periodic,
complex-valued solutions u of the sinh-Gordon equation is developed. Spectral
data for such solutions are defined (following Hitchin and Bobenko) and the
space of spectral data is described by an asymptotic characterization. Using
methods of asymptotic estimates, the inverse problem for the spectral data is
solved along a line, i.e. the solution u is reconstructed on a line from the
spectral data. Finally a Jacobi variety and Abel map for the spectral curve is
constructed; they are used to describe the change of the spectral data under
translation of the solution u.


title: Spin-polarizing interferometric beam splitter for free electrons

abstract:
  A spin-polarizing electron beam splitter is described which relies on an
arrangement of linearly polarized laser waves of nonrelativistic intensity. An
incident electron beam is first coherently scattered off a bichromatic laser
field, splitting the beam into two portions, with electron spin and momentum
being entangled. Afterwards, the partial beams are coherently superposed in an
interferometric setup formed by standing laser waves. As a result, the outgoing
electron beam is separated into its spin components along the laser magnetic
field, which is shown by both analytical and numerical solutions of Pauli's
equation. The proposed laser field configuration thus exerts the same effect on
free electrons like an ordinary Stern-Gerlach magnet does on atoms.


title: Limit theorems for pure death processes coming down from infinity

abstract:
  We consider a pure death process $(Z(t), t\ge0)$ with death rates $\lambda_n$
satisfying the condition $\sum_{n=2}^\infty \lambda_n^{-1}<\infty$ of coming
from infinity, $Z(0)=\infty$, down to an absorbing state $n=1$. We establish
limit theorems for $Z(t)$ as $t\to0$, which strengthen the results that can be
extracted from [1]. We also prove a large deviation theorem assuming that
$\lambda_n$ regularly vary as $n\to\infty$ with an index $ \beta>1$. It
generalises a similar statement with $\beta=2$ obtained in [4] for
$\lambda_n={n\choose 2}$.


title: Loewy lengths of blocks with abelian defect groups

abstract:
  We consider $p$-blocks with abelian defect groups and in the first part prove
a relationship between its Loewy length and that for blocks of normal subgroups
of index $p$. Using this, we show that if $B$ is a $2$-block of a finite group
with abelian defect group $D \cong C_{2^{a_1}} \times \cdots \times C_{2^{a_r}}
\times (C_2)^s$, where $a_i > 1$ for all $i$ and $r \geq 0$, then $d < LL(B)
\leq 2^{a_1}+\cdots+2^{a_r}+2s-r+1$, where $|D|=2^d$. When $s=1$ the upper
bound can be improved to $2^{a_1}+\cdots+2^{a_r}+2-r$. Together these give
sharp upper bounds for every isomorphism type of $D$. A consequence is that
when $D$ is an abelian $2$-group the Loewy length is bounded above by $|D|$
except when $D$ is a Klein-four group and $B$ is Morita equivalent to the
principal block of $A_5$. We conjecture similar bounds for arbitrary primes and
give evidence that it holds for principal $3$-blocks.


title: Decay Mode Solutions to Cylindrical KP Equation

abstract:
  A nonlinear transformation for the cylindrical KP(CKP) equation has been
derived by using the simplified homogeneous balance method (SHB). The 1-decay
mode and 2-decay mode solutions of the CKP equation have been obtained in terms
of the nonlinear transformation derived here. The results obtained in the paper
are different from those obtained in the previous literaturs.


title: Concordance cosmology without dark energy

abstract:
  According to the separate universe conjecture, spherically symmetric
sub-regions in an isotropic universe behave like mini-universes with their own
cosmological parameters. This is an excellent approximation in both Newtonian
and general relativistic theories. We estimate local expansion rates for a
large number of such regions, and use a scale parameter calculated from the
volume-averaged increments of local scale parameters at each time step in an
otherwise standard cosmological $N$-body simulation. The particle mass,
corresponding to a coarse graining scale, is an adjustable parameter. This mean
field approximation neglects tidal forces and boundary effects, but it is the
first step towards a non-perturbative statistical estimation of the effect of
non-linear evolution of structure on the expansion rate. Using our algorithm, a
simulation with an initial $\Omega_m=1$ Einstein--de~Sitter setting closely
tracks the expansion and structure growth history of the $\Lambda$CDM
cosmology. Due to small but characteristic differences, our model can be
distinguished from the $\Lambda$CDM model by future precision observations.
Moreover, our model can resolve the emerging tension between local Hubble
constant measurements and the Planck best-fitting cosmology. Further
improvements to the simulation are necessary to investigate light propagation
and confirm full consistency with cosmic microwave background observations.


title: Synchronization Patterns: From Network Motifs to Hierarchical Networks

abstract:
  We investigate complex synchronization patterns such as cluster
synchronization and partial amplitude death in networks of coupled
Stuart-Landau oscillators with fractal connectivities. The study of fractal or
self-similar topology is motivated by the network of neurons in the brain. This
fractal property is well represented in hierarchical networks, for which we
present three different models. In addition, we introduce an analytical
eigensolution method and provide a comprehensive picture of the interplay of
network topology and the corresponding network dynamics, thus allowing us to
predict the dynamics of arbitrarily large hierarchical networks simply by
analyzing small network motifs. We also show that oscillation death can be
induced in these networks, even if the coupling is symmetric, contrary to
previous understanding of oscillation death. Our results show that there is a
direct correlation between topology and dynamics: Hierarchical networks exhibit
the corresponding hierarchical dynamics. This helps bridging the gap between
mesoscale motifs and macroscopic networks.


title: Particle Filtering with Invertible Particle Flow

abstract:
  A key challenge when designing particle filters in high-dimensional state
spaces is the construction of a proposal distribution that is close to the
posterior distribution. Recent advances in particle flow filters provide a
promising avenue to avoid weight degeneracy; particles drawn from the prior
distribution are migrated in the state-space to the posterior distribution by
solving partial differential equations. Numerous particle flow filters have
been proposed based on different assumptions concerning the flow dynamics.
Approximations are needed in the implementation of all of these filters; as a
result the articles do not exactly match a sample drawn from the desired
posterior distribution. Past efforts to correct the discrepancies involve
expensive calculations of importance weights. In this paper, we present new
filters which incorporate deterministic particle flows into an encompassing
particle filter framework. The valuable theoretical guarantees concerning
particle filter performance still apply, but we can exploit the attractive
performance of the particle flow methods. The filters we describe involve a
computationally efficient weight update step, arising because the embedded
particle flows we design possess an invertible mapping property. We evaluate
the proposed particle flow particle filters' performance through numerical
simulations of a challenging multi-target multi-sensor tracking scenario and
complex high-dimensional filtering examples.


title:
Recovery of a SINIS turnstile accuracy in a strongly non-equilibrium
  regime

abstract:
  We perform a theoretical study of non-equilibrium effects in charge transport
through a hybrid single-electron transistor based on a small normal metal (N)
island with the gate-controlled number of electrons, tunnel-coupled to
voltage-biased superconducting (S) electrodes (SINIS). Focusing on the
turnstile mode of the transistor operation with the gate voltage driven
periodically, and electrons on the island being out of equilibrium, we find
that the current quantization accuracy is a non-monotonic function of the
relaxation rate $\Gamma_{\mathcal{F}}$ of the distribution function
$\mathcal{F}(\epsilon)$ on the island due to tunneling, as compared to the
drive frequency $f$, electron-electron $1/\tau_{ee}$ and electron-phonon
$1/\tau_{eph}$ relaxation rates. Surprisingly, in the strongly non-equilibrium
regime, $f\gg \Gamma_{\mathcal{F}}\gg\tau_{ee}^{-1},\tau_{eph}^{-1}$, the
turnstile current plateau is recovered, similarly to the ideal equilibrium
regime, $\tau_{eph}^{-1}\gg \Gamma_{\mathcal{F}}$. The plateau is destroyed in
the quasiequilibrium regime when the electron-electron relaxation is faster
than tunneling.


title:
Dispersive readout of valley splittings in cavity-coupled silicon
  quantum dots

abstract:
  The bandstructure of bulk silicon has a six-fold valley degeneracy. Strain in
the Si/SiGe quantum well system partially lifts the valley degeneracy, but the
materials factors that set the splitting of the two lowest lying valleys are
still under intense investigation. We propose a method for accurately
determining the valley splitting in Si/SiGe double quantum dots embedded into a
superconducting microwave resonator. We show that low lying valley states in
the double quantum dot energy level spectrum lead to readily observable
features in the cavity transmission. These features generate a "fingerprint" of
the microscopic energy level structure of a semiconductor double quantum dot,
providing useful information on valley splittings and intervalley coupling
rates.


title: Refined long time asymptotics for Fisher-KPP fronts

abstract:
  We study the one-dimensional Fisher-KPP equation, with an initial condition
$u_0(x)$ that coincides with the step function except on a compact set. A
well-known result of M. Bramson states that, as $t\to+\infty$, the solution
converges to a traveling wave located at the position $X(t)=2t-(3/2)\log
t+x_0+o(1)$, with the shift $x_0$ that depends on $u_0$. U. Ebert and W. Van
Saarloos have formally derived a correction to the Bramson shift, arguing that
$X(t)=2t-(3/2)\log t+x_0-3\sqrt{\pi}/\sqrt{t}+O(1/t)$. Here, we prove that this
result does hold, with an error term of the size $O(1/t^{1-\gamma})$, for any
$\gamma>0$. The interesting aspect of this asymptotics is that the coefficient
in front of the $1/\sqrt{t}$-term does not depend on $u_0$.


title: A symmetrization result for a class of anisotropic elliptic problems

abstract:
  We prove estimates for weak solutions to a class of Dirichlet problems
associated to anisotropic elliptic equations with a zero order term.


title:
Finite-Time and -Size Scalings in the Evaluation of Large Deviation
  Functions: Numerical Approach in Continuous Time

abstract:
  Rare trajectories of stochastic systems are important to understand --
because of their potential impact. However, their properties are by definition
difficult to sample directly. Population dynamics provides a numerical tool
allowing their study, by means of simulating a large number of copies of the
system, which are subjected to selection rules that favor the rare trajectories
of interest. Such algorithms are plagued by finite simulation time- and finite
population size- effects that can render their use delicate. In this paper, we
present a numerical approach which uses the finite-time and finite-size
scalings of estimators of the large deviation functions associated to the
distribution of rare trajectories. The method we propose allows one to extract
the infinite-time and infinite-size limit of these estimators which -- as shown
on the contact process -- provides a significant improvement of the large
deviation functions estimators compared to the the standard one.


title:
Submodular Secretary Problems: Cardinality, Matching, and Linear
  Constraints

abstract:
  We study various generalizations of the secretary problem with submodular
objective functions. Generally, a set of requests is revealed step-by-step to
an algorithm in random order. For each request, one option has to be selected
so as to maximize a monotone submodular function while ensuring feasibility.
For our results, we assume that we are given an offline algorithm computing an
$\alpha$-approximation for the respective problem. This way, we separate
computational limitations from the ones due to the online nature. When only
focusing on the online aspect, we can assume $\alpha = 1$.
  In the submodular secretary problem, feasibility constraints are cardinality
constraints. That is, out of a randomly ordered stream of entities, one has to
select a subset size $k$. For this problem, we present a
$0.31\alpha$-competitive algorithm for all $k$, which asymptotically reaches
competitive ratio $\frac{\alpha}{e}$ for large $k$. In submodular secretary
matching, one side of a bipartite graph is revealed online. Upon arrival, each
node has to be matched permanently to an offline node or discarded irrevocably.
We give an $\frac{\alpha}{4}$-competitive algorithm. In both cases, we improve
over previously best known competitive ratios, using a generalization of the
algorithm for the classic secretary problem.
  Furthermore, we give an $O(\alpha d^{-\frac{2}{B-1}})$-competitive algorithm
for submodular function maximization subject to linear packing constraints.
Here, $d$ is the column sparsity, that is the maximal number of none-zero
entries in a column of the constraint matrix, and $B$ is the minimal capacity
of the constraints. Notably, this bound is independent of the total number of
constraints. We improve the algorithm to be $O(\alpha
d^{-\frac{1}{B-1}})$-competitive if both $d$ and $B$ are known to the algorithm
beforehand.


title: Trimming and gluing Gray codes

abstract:
  We consider the algorithmic problem of generating each subset of
$[n]:=\{1,2,\ldots,n\}$ whose size is in some interval $[k,l]$, $0\leq k\leq
l\leq n$, exactly once (cyclically) by repeatedly adding or removing a single
element, or by exchanging a single element. For $k=0$ and $l=n$ this is the
classical problem of generating all $2^n$ subsets of $[n]$ by element
additions/removals, and for $k=l$ this is the classical problem of generating
all $\binom{n}{k}$ subsets of $[n]$ by element exchanges. We prove the
existence of such cyclic minimum-change enumerations for a large range of
values $n$, $k$, and $l$, improving upon and generalizing several previous
results. For all these existential results we provide optimal algorithms to
compute the corresponding Gray codes in constant $\mathcal{O}(1)$ time per
generated set and $\mathcal{O}(n)$ space. Rephrased in terms of graph theory,
our results establish the existence of (almost) Hamilton cycles in the subgraph
of the $n$-dimensional cube $Q_n$ induced by all levels $[k,l]$. We reduce all
remaining open cases to a generalized version of the middle levels conjecture,
which asserts that the subgraph of $Q_{2k+1}$ induced by all levels
$[k-c,k+1+c]$, $c\in\{0,1,\ldots,k\}$, has a Hamilton cycle. We also prove an
approximate version of this generalized conjecture, showing that this graph has
a cycle that visits a $(1-o(1))$-fraction of all vertices.


title:
Extracting Food Substitutes From Food Diary via Distributional
  Similarity

abstract:
  In this paper, we explore the problem of identifying substitute relationship
between food pairs from real-world food consumption data as the first step
towards the healthier food recommendation. Our method is inspired by the
distributional hypothesis in linguistics. Specifically, we assume that foods
that are consumed in similar contexts are more likely to be similar dietarily.
For example, a turkey sandwich can be considered a suitable substitute for a
chicken sandwich if both tend to be consumed with french fries and salad. To
evaluate our method, we constructed a real-world food consumption dataset from
MyFitnessPal's public food diary entries and obtained ground-truth human
judgements of food substitutes from a crowdsourcing service. The experiment
results suggest the effectiveness of the method in identifying suitable
substitutes.


title:
A multi-parameter Lie transform method applied to the transform of the
  Lagrangian differential one-form

abstract:
  In this paper, to fit the multi-scale perturbations, the single-parameter Lie
transform perturbation theory given in [Ann Phys, 151 1 (1983)] is generalized
to a multi-parameter case, which provides a formal solution of the new
Lagrangian differential 1-form transformed from the old one. In the new method,
the generators and their orders are appropriately chosen under the purpose of
reducing the fast variables from the new Lagrangian differential 1-form order
by order. As for the application, this multi-parameter Lie transform method is
applied to deriving the gyrokinetic model with the presentation of
low-frequency electrostatic perturbations. Compared with the conventional
model, the Finite Larmor Radius terms in the Lagrangian 1-form of the new model
are perfectly cancelled, without using any gauge function.


title:
Adapting polytopes dimension for managing degrees of freedom in
  tolerancing analysis

abstract:
  In tolerancing analysis, geometrical or contact specifications can be
represented by polytopes. Due to the degrees of invariance of surfaces and that
of freedom of joints, these operand polytopes are originally unbounded in most
of the cases (i.e. polyhedra). Homri et al. proposed the introduction of
virtual boundaries (called cap half-spaces) over the unbounded displacements of
each polyhedron to turn them into 6-polytopes. This decision was motivated by
the complexity that operating on polyhedra in R6 supposes. However, that
strategy has to face the multiplication of the number of cap half-spaces during
the computation of Minkowski sums. In general, the time for computing cap
facets is greater than for computing facets representing real limits of bounded
displacements. In order to deal with that, this paper proposes the use of the
theory of screws to determine the set of displacements that defines the
positioning of one surface in relation to another. This set of displacements
defines the subspace of R6 in which the polytopes of the respective surfaces
have to be projected and operated to avoid calculating facets and vertices
along the directions of unbounded displacements. With this new strategy it is
possible to decrease the complexity of the Minkowski sums by reducing the
dimension of the operands and consequently reducing the computation time. An
example illustrates the method and shows the time reduction during the
computations.


title:
Polynomial Networks and Factorization Machines: New Insights and
  Efficient Training Algorithms

abstract:
  Polynomial networks and factorization machines are two recently-proposed
models that can efficiently use feature interactions in classification and
regression tasks. In this paper, we revisit both models from a unified
perspective. Based on this new view, we study the properties of both models and
propose new efficient training algorithms. Key to our approach is to cast
parameter learning as a low-rank symmetric tensor estimation problem, which we
solve by multi-convex optimization. We demonstrate our approach on regression
and recommender system tasks.


title: Can a CNN Recognize Catalan Diet?

abstract:
  Nowadays, we can find several diseases related to the unhealthy diet habits
of the population, such as diabetes, obesity, anemia, bulimia and anorexia. In
many cases, these diseases are related to the food consumption of people.
Mediterranean diet is scientifically known as a healthy diet that helps to
prevent many metabolic diseases. In particular, our work focuses on the
recognition of Mediterranean food and dishes. The development of this
methodology would allow to analise the daily habits of users with wearable
cameras, within the topic of lifelogging. By using automatic mechanisms we
could build an objective tool for the analysis of the patient's behaviour,
allowing specialists to discover unhealthy food patterns and understand the
user's lifestyle.
  With the aim to automatically recognize a complete diet, we introduce a
challenging multi-labeled dataset related to Mediterranean diet called FoodCAT.
The first type of label provided consists of 115 food classes with an average
of 400 images per dish, and the second one consists of 12 food categories with
an average of 3800 pictures per class. This dataset will serve as a basis for
the development of automatic diet recognition. In this context, deep learning
and more specifically, Convolutional Neural Networks (CNNs), currently are
state-of-the-art methods for automatic food recognition. In our work, we
compare several architectures for image classification, with the purpose of
diet recognition. Applying the best model for recognising food categories, we
achieve a top-1 accuracy of 72.29\%, and top-5 of 97.07\%. In a complete diet
recognition of dishes from Mediterranean diet, enlarged with the Food-101
dataset for international dishes recognition, we achieve a top-1 accuracy of
68.07\%, and top-5 of 89.53\%, for a total of 115+101 food classes.


title:
Exploring the "Middle Earth" of Network Spectra via a Gaussian Matrix
  Function

abstract:
  We study a Gaussian matrix function of the adjacency matrix of artificial and
real-world networks. In particular, we study the Gaussian Estrada index---an
index characterizing the importance of eigenvalues close to zero. This index
accounts for the information contained in the eigenvalues close to zero in the
spectra of networks. Here we obtain bounds for this index in simple graphs,
proving that it reaches its maximum for star graphs followed by complete
bipartite graphs. We also obtain formulas for the Estrada Gaussian index of
Erd\H{o}s-R\'enyi random graphs as well as for the Barab\'asi-Albert graphs. We
also show that in real-world networks this index is related to the existence of
important structural patterns, such as complete bipartite subgraphs
(bicliques). Such bicliques appear naturally in many real-world networks as a
consequence of the evolutionary processes giving rise to them. In general, the
Gaussian matrix function of the adjacency matrix of networks characterizes
important structural information not described in previously used matrix
functions of graphs.


title:
Fluence dependent femtosecond quasi-particle and Eu^{2+} -spin
  relaxation dynamics in EuFe_{2}(As,P)_{2}

abstract:
  We investigated temperature and fluence dependent dynamics of the time
resolved optical reflectivity in undoped spin-density-wave (SDW) and doped
superconducting (SC) EuFe$_{2}$(As,P)$_{2}$ with emphasis on the ordered
Eu$^{2+}$-spin temperature region. The data indicate that the SDW order
coexists at low temperature with the SC and Eu$^{2+}$-ferromagnetic order.
Increasing the excitation fluence leads to a thermal suppression of the
Eu$^{2+}$-spin order due to the crystal-lattice heating while the SDW order is
suppressed nonthermally at a higher fluence.


title: Hyperuniformity and its Generalizations

abstract:
  Disordered many-particle hyperuniform systems are exotic amorphous states
characterized by anomalous suppression of large-scale density fluctuations.
Here we substantially broaden the hyperuniformity concept along four different
directions. This includes generalizations to treat fluctuations in the
interfacial area in heterogeneous media and surface-area driven evolving
microstructures, random scalar fields, divergence-free random vector fields, as
well as statistically anisotropic many-particle systems and two-phase media.
Interfacial-area fluctuations play a major role in characterizing the
microstructure of two-phase systems , physical properties that intimately
depend on the geometry of the interface, and evolving two-phase microstructures
that depend on interfacial energies (e.g., spinodal decomposition). In the
instances of divergence-free random vector fields and statistically anisotropic
structures, we show that the standard definition of hyperuniformity must be
generalized such that it accounts for the dependence of the relevant spectral
functions on the direction in which the origin in Fourier space
(nonanalyticities at the origin). Using this analysis, we place some well-known
energy spectra from the theory of isotropic turbulence in the context of this
generalization of hyperuniformity. We show that there exist many-particle
ground-state configurations in which directional hyperuniformity imparts exotic
anisotropic physical properties (e.g., elastic, optical and acoustic
characteristics) to these states of matter. Such tunablity could have
technological relevance for manipulating light and sound waves in ways
heretofore not thought possible. We show that disordered many-particle systems
that respond to external fields (e.g., magnetic and electric fields) are a
natural class of materials to look for directional hyperuniformity.


title:
Contribution of jumping numbers by exceptional divisors, with an
  appendix by Karen E. Smith and Kevin Tucker

abstract:
  We investigate some necessary and sufficient conditions for an exceptional
divisor to contribute jumping numbers of an effective divisor on a variety of
arbitrary dimension, inspired by the results for curves on surfaces by Smith
and Thompson and Tucker. In particular, we construct an example of an
exceptional divisor that is not contracted in the log canonical model, and does
not contribute any jumping numbers.


title: Arithmetic invariant theory and 2-descent for plane quartic curves

abstract:
  Given a smooth plane quartic curve C over a field k of characteristic 0, with
Jacobian variety J, and a marked rational point P of C(k), we construct a
reductive group G and a G-variety X, together with an injection J(k)/2J(k) ->
G(k)\X(k). We do this using the Mumford theta group of J, and a construction of
Lurie which passes from Heisenberg groups to Lie algebras.


title:
NNLO QCD corrections to Higgs boson production at large transverse
  momentum

abstract:
  We derive the second-order QCD corrections to the production of a Higgs boson
recoiling against a parton with finite transverse momentum, working in the
effective field theory in which the top quark contributions are integrated out.
To account for quark mass effects, we supplement the effective field theory
result by the full quark mass dependence at leading order. Our calculation is
fully differential in the final state kinematics and includes the decay of the
Higgs boson to a photon pair. It allows one to make next-to-next-to- leading
order (NNLO)-accurate theory predictions for Higgs-plus-jet final states and
for the transverse momentum distribution of the Higgs boson, accounting for the
experimental definition of the fiducial cross sections. The NNLO QCD
corrections are found to be moderate and positive, they lead to a substantial
reduction of the theory uncertainty on the predictions. We compare our results
to 8 TeV LHC data from ATLAS and CMS. While the shape of the data is
well-described for both experiments, we agree on the normalization only for
CMS. By normalizing data and theory to the inclusive fiducial cross section for
Higgs production, good agreement is found for both experiments, however at the
expense of an increased theory uncertainty. We make predictions for Higgs
production observables at the 13 TeV LHC, which are in good agreement with
recent ATLAS data. At this energy, the leading order mass corrections to the
effective field theory prediction become significant at large transverse
momenta, and we discuss the resulting uncertainties on the predictions.


title:
An Opportunistic Search for ExtraTerrestrial Intelligence (SETI) with
  the Murchison Widefield Array

abstract:
  A spectral line image cube generated from 115 minutes of MWA data that covers
a field of view of 400 sq. deg. around the Galactic Centre is used to perform
the first Search for ExtraTerrestrial Intelligence (SETI) with the Murchison
Widefield Array. Our work constitutes the first modern SETI experiment at low
radio frequencies, here between 103 and 133 MHz, paving the way for large-scale
searches with the MWA and, in the future, the low frequency Square Kilometre
Array. Limits of a few hundred mJy/beam for narrow band emission (10 kHz) are
derived from our data, across our 400 sq. deg. field of view. Within this
field, 45 exoplanets in 38 planetary systems are known. We extract spectra at
the locations of these systems from our image cube, to place limits on the
presence of narrow line emission from these systems. We then derive minimum
isotropic transmitter powers for these exoplanets; a small handful of the
closest objects (10s of pc) yield our best limits of order $10^{14}$ W
(Equivalent Isotropic Radiated Power: EIRP). These limits lie above the highest
power directional transmitters near these frequencies currently operational on
Earth. A SETI experiment with the MWA covering the full accessible sky and its
full frequency range would require approximately one month of observing time.
The MWA frequency range, its Southern Hemisphere location on an extraordinarily
radio quiet site, its very large field of view, and its high sensitivity make
it a unique facility for SETI.


title:
Automated tracking of colloidal clusters with sub-pixel accuracy and
  precision

abstract:
  Quantitative tracking of features from video images is a basic technique
employed in many areas of science. Here, we present a method for the tracking
of features that partially overlap, in order to be able to track so-called
colloidal molecules. Our approach implements two improvements into existing
particle tracking algorithms. Firstly, we use the history of previously
identified feature locations to successfully find their positions in
consecutive frames. Secondly, we present a framework for non-linear
least-squares fitting to summed radial model functions and analyze the accuracy
(bias) and precision (random error) of the method on artificial data. We find
that our tracking algorithm correctly identifies overlapping features with an
accuracy below 0.2% of the feature radius and a precision of 0.1 to 0.01 pixels
for a typical image of a colloidal cluster. Finally, we use our method to
extract the three-dimensional diffusion tensor from the Brownian motion of
colloidal dimers.


title:
Dispersion by pulsars, magnetars, fast radio bursts and massive
  electromagnetism at very low radio frequencies

abstract:
  Our understanding of the universe relies mostly on electromagnetism. As
photons are the messengers, fundamental physics is concerned in testing their
properties. Photon mass upper limits have been earlier set through pulsar
observations, but new investigations are offered by the excess of dispersion
measure (DM) sometimes observed with pulsar and magnetar data at low
frequencies, or with the fast radio bursts (FRBs), of yet unknown origin.
Arguments for the excess of DM do not reach a consensus, but are not mutually
exclusive. Thus, we remind that for massive electromagnetism, dispersion goes
as the inverse of the frequency squared. Thereby, new avenues are offered also
by the recently operating ground observatories in 10-80 MHz domain and by the
proposed Orbiting Low Frequency Antennas for Radio astronomy (OLFAR). The
latter acts as a large aperture dish by employing a swarm of nano-satellites
observing the sky for the first time in the 0.1 - 15 MHz spectrum. The swarm
must be deployed sufficiently away from the ionosphere to avoid distortions
especially during the solar maxima, terrestrial interference and offer stable
conditions for calibration during observations.


title: Predicting Anchor Links between Heterogeneous Social Networks

abstract:
  People usually get involved in multiple social networks to enjoy new services
or to fulfill their needs. Many new social networks try to attract users of
other existing networks to increase the number of their users. Once a user
(called source user) of a social network (called source network) joins a new
social network (called target network), a new inter-network link (called anchor
link) is formed between the source and target networks. In this paper, we
concentrated on predicting the formation of such anchor links between
heterogeneous social networks. Unlike conventional link prediction problems in
which the formation of a link between two existing users within a single
network is predicted, in anchor link prediction, the target user is missing and
will be added to the target network once the anchor link is created. To solve
this problem, we use meta-paths as a powerful tool for utilizing heterogeneous
information in both the source and target networks. To this end, we propose an
effective general meta-path-based approach called Connector and Recursive
Meta-Paths (CRMP). By using those two different categories of meta-paths, we
model different aspects of social factors that may affect a source user to join
the target network, resulting in the formation of a new anchor link. Extensive
experiments on real-world heterogeneous social networks demonstrate the
effectiveness of the proposed method against the recent methods.


title: SPICE: Semantic Propositional Image Caption Evaluation

abstract:
  There is considerable interest in the task of automatically generating image
captions. However, evaluation is challenging. Existing automatic evaluation
metrics are primarily sensitive to n-gram overlap, which is neither necessary
nor sufficient for the task of simulating human judgment. We hypothesize that
semantic propositional content is an important component of human caption
evaluation, and propose a new automated caption evaluation metric defined over
scene graphs coined SPICE. Extensive evaluations across a range of models and
datasets indicate that SPICE captures human judgments over model-generated
captions better than other automatic metrics (e.g., system-level correlation of
0.88 with human judgments on the MS COCO dataset, versus 0.43 for CIDEr and
0.53 for METEOR). Furthermore, SPICE can answer questions such as `which
caption-generator best understands colors?' and `can caption-generators count?'


title: eXTP -- enhanced X-ray Timing and Polarimetry Mission

abstract:
  eXTP is a science mission designed to study the state of matter under extreme
conditions of density, gravity and magnetism. Primary targets include isolated
and binary neutron stars, strong magnetic field systems like magnetars, and
stellar-mass and supermassive black holes. The mission carries a unique and
unprecedented suite of state-of-the-art scientific instruments enabling for the
first time ever the simultaneous spectral-timing-polarimetry studies of cosmic
sources in the energy range from 0.5-30 keV (and beyond). Key elements of the
payload are: the Spectroscopic Focusing Array (SFA) - a set of 11 X-ray optics
for a total effective area of about 0.9 m^2 and 0.6 m^2 at 2 keV and 6 keV
respectively, equipped with Silicon Drift Detectors offering <180 eV spectral
resolution; the Large Area Detector (LAD) - a deployable set of 640 Silicon
Drift Detectors, for a total effective area of about 3.4 m^2, between 6 and 10
keV, and spectral resolution <250 eV; the Polarimetry Focusing Array (PFA) - a
set of 2 X-ray telescope, for a total effective area of 250 cm^2 at 2 keV,
equipped with imaging gas pixel photoelectric polarimeters; the Wide Field
Monitor (WFM) - a set of 3 coded mask wide field units, equipped with
position-sensitive Silicon Drift Detectors, each covering a 90 degrees x 90
degrees FoV. The eXTP international consortium includes mostly major
institutions of the Chinese Academy of Sciences and Universities in China, as
well as major institutions in several European countries and the United States.
The predecessor of eXTP, the XTP mission concept, has been selected and funded
as one of the so-called background missions in the Strategic Priority Space
Science Program of the Chinese Academy of Sciences since 2011. The strong
European participation has significantly enhanced the scientific capabilities
of eXTP. The planned launch date of the mission is earlier than 2025.


title: Ferromagnetic detection of moduli dark matter

abstract:
  We propose a scheme to detect light scalar moduli dark matter, based on
measuring the change of magnetization induced in a macroscopic hard
ferromagnet. Our method can probe moduli dark matter at the natural coupling to
the electron mass over several orders of magnitude in the moduli mass. The most
attracting feature of the proposed approach, compared to mechanical ones, is
that it relies on a nonresonant detection, allowing to probe a much wider
region of the parameter space. This is a crucial point, as long as the theory
is not able to predict the moduli mass.


title:
Doubled Lattice Chern-Simons-Yang-Mills Theories with Discrete Gauge
  Group

abstract:
  We construct doubled lattice Chern-Simons-Yang-Mills theories with discrete
gauge group $G$ in the Hamiltonian formulation. Here, these theories are
considered on a square spatial lattice and the fundamental degrees of freedom
are defined on pairs of links from the direct lattice and its dual,
respectively. This provides a natural lattice construction for
topologically-massive gauge theories, which are invariant under parity and
time-reversal symmetry. After defining the building blocks of the doubled
theories, paying special attention to the realization of gauge transformations
on quantum states, we examine the dynamics in the group space of a single
cross, which is spanned by a single link and its dual. The dynamics is governed
by the single-cross electric Hamiltonian and admits a simple quantum mechanical
analogy to the problem of a charged particle moving on a discrete space
affected by an abstract electromagnetic potential. Such a particle might
accumulate a phase shift equivalent to an Aharonov-Bohm phase, which is
manifested in the doubled theory in terms of a nontrivial ground-state
degeneracy on a single cross. We discuss several examples of these doubled
theories with different gauge groups including the cyclic group
$\mathbb{Z}(k)\subset U(1)$, the symmetric group $S_3\subset O(2)$, the binary
dihedral (or quaternion) group $\bar{D}_2\subset SU(2)$, and the finite group
$\Delta(27)\subset SU(3)$. In each case the spectrum of the single-cross
electric Hamiltonian is determined exactly. We examine the nature of the
low-lying excited states in the full Hilbert space, and emphasize the role of
the center symmetry for the confinement of charges. Whether the investigated
doubled models admit a non-Abelian topological state which allows for
fault-tolerant quantum computation will be addressed in a future publication.


title:
The Constrained Maximum Likelihood Estimation For Parameters Arising
  From Partially Identified Models

abstract:
  We extend the constrained maximum likelihood estimation theory for parameters
of a completely identified model, proposed by Aitchison and Silvey (1958), to
parameters arising from a partially identified model. With a partially
identified model, some parameters of the model may only be identified through
constraints imposed by additional assumptions. We show that, under certain
conditions, the constrained maximum likelihood estimator exists and locally
maximize the likelihood function subject to constraints. We then study the
asymptotic distribution of the estimator and propose a numerical algorithm for
estimating parameters. We also discuss a special situation where exploiting
additional assumptions does not improve estimation efficiency.


title:
Clustering nonstationary circadian rhythms using locally stationary
  wavelet representations

abstract:
  How does soil pollution affect a plant's circadian clock? Are there any
differences between how the clock reacts when exposed to different
concentrations of elements of the periodic table? If so, can we characterise
these differences?
  We approach these questions by analysing and modelling circadian plant data,
where the levels of expression of a luciferase reporter gene were measured at
regular intervals over a number of days after exposure to different
concentrations of lithium.
  A key aspect of circadian data analysis is to determine whether a time series
(derived from experimental data) is `rhythmic' and, if so, to determine the
underlying period. However, our dataset displays nonstationary traits such as
changes in amplitude, gradual changes in period and phase-shifts.
  In this paper, we develop clustering methods using a wavelet transform.
Wavelets are chosen as they are ideally suited to identifying discriminant
local time and scale features. Furthermore, we propose treating the observed
time series as realisations of locally stationary wavelet processes. This
allows us to define and estimate the evolutionary wavelet spectrum. We can then
compare, in a quantitative way, using a functional principal components
analysis, the time-frequency patterns of the time series. Our approach uses a
clustering algorithm to group the data according to their time-frequency
patterns. We demonstrate the advantages of our methodology over alternative
approaches and show that it successfully clusters our data.


title: e-MERLIN 21cm constraints on the mass-loss rates of OB stars in Cyg OB2

abstract:
  We present e-MERLIN 21 cm (L-band) observations of single luminous OB stars
in the Cygnus OB2 association, from the COBRaS Legacy programme. The radio
observations potentially offer the most straightforward, least model-dependent,
determinations of mass-loss rates, and can be used to help resolve current
discrepancies in mass-loss rates via clumped and structured hot star winds. We
report here that the 21 cm flux densities of O3 to O6 supergiant and giant
stars are less than ~ 70 microJy. These fluxes may be translated to `smooth'
wind mass-loss upper limits of ~ 4.4 - 4.8 x 10^(-6) M_sol/yr for O3
supergiants and < 2.9 x 10^(-6) M_sol/yr for B0 to B1 supergiants. The first
ever resolved 21 cm detections of the hypergiant (and LBV candidate) Cyg OB2
#12 are discussed; for multiple observations separated by 14 days, we detect a
~ 69% increase in its flux density. Our constraints on the upper limits for the
mass-loss rates of evolved OB stars in Cyg OB2 support the model that the inner
wind region close to the stellar surface (where Halpha forms) is more clumped
than the very extended geometric region sampled by our radio observations.


title: Structure and magnetism of the $(2 \times 2)$-FeO(111) surface

abstract:
  Based on ab initio calculations we determine the features and relative
stability of different models proposed to describe the $(2 \times 2)$-FeO(111)
reconstruction. Our results suggest that both wurtzite and spinel-like
environments are possible, and their coexistence explains phenomena of biphase
ordering. The surface phase diagram reflects a competition of charge and
magnetic compensation effects, and reveals the important influence of the
substrate on the final surface structure. Though antiferromagnetic couplings
are dominant, frustration and the delicate balance of surface and bulk exchange
interactions lead to a net surface magnetization that accounts for the large
measured values.


title:
Absorption cross-sections of small quasi-spherical black holes: the
  massless scalar case

abstract:
  We consider effects of non-uniformity of quasi-spherical small black hole
horizons on scattering massless spineless particles in the long-wave
approximation. Focusing on 4D flat and AdS neutral black hole backgrounds with
conformally spherical geometry of the horizon, we observe the notable
differences in compare to the scattering process on the spherically-symmetric
black holes. In particular, the absorption cross-section becomes dependent on
both, polar and azimuthal, spherical angles, projections of the angular
momentum do not keep anymore and the angular momentum operator by itself,
though remains quantised, is not quantised in integers. However, within the
long-wave approximation, the main conclusion of previously obtained results on
scattering on the spherically-symmetric black holes remains the same: the total
absorption cross-section is proportional to the area of the black hole. The
proportionality coefficient does not depend on the scalar wave frequency in the
flat space black hole background, and is dependent on the admissible from the
unitarity requirement frequencies in the background of AdS black hole. As a
by-product of our studies we establish a quasi-spherical non-static Vaidya-type
black hole solutions and outline the relation between real solutions to the
elliptic Liouville equation on 2D plane and on two-dimensional sphere.


title: Twisted bilayer blue phosphorene: A direct band gap semiconductor

abstract:
  We report that two rotated layers of blue phosphorene behave as a direct band
gap semiconductor. The optical spectrum shows absorption peaks in the visible
region of the spectrum and in addition the energy of these peaks can be tuned
with the rotational angle. These findings makes twisted bilayer blue
phosphorene a strong candidate as a solar cell or photodetection device. Our
results are based on ab initio calculations of several rotated blue phosphorene
layers.


title: A note on the order of iterated line digraphs

abstract:
  Given a digraph $G$, we propose a new method to find the recurrence equation
for the number of vertices $n_k$ of the $k$-iterated line digraph $L^k(G)$, for
$k\geq0$, where $L^0(G)=G$. We obtain this result by using the minimal
polynomial of a quotient digraph $\pi(G)$ of $G$. We show some examples of this
method applied to the so-called cyclic Kautz, the unicyclic, and the acyclic
digraphs. In the first case, our method gives the enumeration of the ternary
length-2 squarefree words of any length.


title:
The Sunyaev-Zel'dovich Effect at Five Arc-seconds: RXJ1347.5-1145 Imaged
  by ALMA

abstract:
  We present the first image of the thermal Sunyaev-Zel'dovich effect (SZE)
obtained by the Atacama Large Millimeter/submillimeter Array (ALMA). Combining
7-m and 12-m arrays in Band 3, we create an SZE map toward a galaxy cluster
RXJ1347.5-1145 with 5 arc-second resolution (corresponding to the physical size
of 20 kpc/h), the highest angular and physical spatial resolutions achieved to
date for imaging the SZE, while retaining extended signals out to 40
arc-seconds. The 1-sigma statistical sensitivity of the image is 0.017 mJy/beam
or 0.12 mK_CMB at the 5 arc-second full width at half maximum. The SZE image
shows a good agreement with an electron pressure map reconstructed
independently from the X-ray data and offers a new probe of the small-scale
structure of the intracluster medium. Our results demonstrate that ALMA is a
powerful instrument for imaging the SZE in compact galaxy clusters with
unprecedented angular resolution and sensitivity. As the first report on the
detection of the SZE by ALMA, we present detailed analysis procedures including
corrections for the missing flux, to provide guiding methods for analyzing and
interpreting future SZE images by ALMA.


title:
Measurement of the ZZ production cross section and Z to l+l-l'+l'-
  branching fraction in pp collisions at sqrt(s) = 13 TeV

abstract:
  Four-lepton production in proton-proton collisions, pp to
(Z/gamma*)(Z/gamma*) to l+l-l'+l'-, where l, l' = e or mu, is studied at a
center-of-mass energy of 13 TeV with the CMS detector at the LHC. The data
sample corresponds to an integrated luminosity of 2.6 inverse femtobarns. The
ZZ production cross section, sigma(pp to ZZ) = 14.6 +1.9/-1.8 (stat) +0.5/-0.3
(syst) +/- 0.2 (theo) +/- 0.4 (lumi) pb, is measured for events with two
opposite-sign, same-flavor lepton pairs produced in the mass region 60 <
m[l+l-], m[l'+l'-] < 120 GeV. The Z boson branching fraction to four leptons is
measured to be B(Z to l+l-l'+l'-) = 4.9 +0.8/-0.7 (stat) +0.3/-0.2 (syst)
+0.2/-0.1 (theo) +/- 0.1 (lumi) x E-6 for the four-lepton invariant mass in the
range 80 < m[l+l-l'+l'-] < 100 GeV and dilepton mass m[l+l-] > 4 GeV for all
opposite-sign, same-flavor lepton pairs. The results are in agreement with
standard model predictions.


title: Fine compactified moduli of enriched structures on stable curves

abstract:
  Enriched structures on stable curves over fields were defined by Maino in the
late 1990s, and have played an important role in the study of limit linear
series and degenerating jacobians. In this paper we solve three main problems:
we give a definition of enriched structures on stable curves over arbitrary
base schemes, and show that the resulting fine moduli problem is representable;
we show that the resulting object has a universal property in terms of N\'eron
models; and we construct a compactification of our stack of enriched
structures.


title:
Numerical modeling of the acoustic wave propagation across an
  homogenized rigid microstructure in the time domain

abstract:
  Homogenization of a thin micro-structure yields effective jump conditions
that incorporate the geometrical features of the scatterers. These jump
conditions apply across a thin but nonzero thickness interface whose interior
is disregarded. This paper aims (i) to propose a numerical method able to
handle the jump conditions in order to simulate the homogenized problem in the
time domain, (ii) to inspect the validity of the homogenized problem when
compared to the real one. For this purpose, we adapt an immersed interface
method originally developed for standard jump conditions across a
zero-thickness interface. Doing so allows us to handle arbitrary-shaped
interfaces on a Cartesian grid with the same efficiency and accuracy of the
numerical scheme than those obtained in an homogeneous medium. Numerical
experiments are performed to test the properties of the numerical method and to
inspect the validity of the homogenization problem.


title: On the addition of squares of units modulo n

abstract:
  Let $\mathbb{Z}_n$ be the ring of residue classes modulo $n$, and let
$\mathbb{Z}_n^{\ast}$ be the group of its units. 90 years ago, Brauer obtained
a formula for the number of representations of $c\in \mathbb{Z}_n$ as the sum
of $k$ units. Recently, Yang and Tang in [Q. Yang, M. Tang, On the addition of
squares of units and nonunits modulo $n$, J. Number Theory., 155 (2015) 1--12]
gave a formula for the number of solutions of the equation $x_1^2+x_2^2=c$ with
$x_{1},x_{2}\in \mathbb{Z}_n^{\ast}$. In this paper, we generalize this result.
We find an explicit formula for the number of solutions of the equation
$x^2_{1}+\cdots+x^2_{k}=c$ with $x_{1},\ldots,x_{k}\in \mathbb{Z}_n^{\ast}$.


title:
A Suggested Answer To Wallstrom's Criticism: Zitterbewegung Stochastic
  Mechanics II

abstract:
  The "zitterbewegung stochastic mechanics" (ZSM) answer to Wallstrom's
criticism, introduced in the companion paper [1], is extended to many
particles. We first formulate the many-particle generalization of Nelson-Yasue
stochastic mechanics (NYSM), incorporating external and classical interaction
potentials. Then we formulate the many-particle generalization of the classical
zitterbewegung \emph{zbw} model introduced in Part I, for the cases of free
particles, particles interacting with external fields, and classically
interacting particles. On the basis of these developments, ZSM is constructed
for classically free particles, as well as for particles interacting both with
external fields and through inter-particle scalar potentials. Throughout, the
beables of ZSM (based on the many-particle formulation) are made explicit.
Subsequently, we assess the plausibility and generalizability of the\emph{zbw}
hypothesis. We close with an appraisal of other proposed answers, and compare
them to ZSM.


title:
Bounded solutions and asymptotic stability to nonlinear second-order
  neutral difference equations with quasi-differences

abstract:
  This work is devoted to the study of the nonlinear second-order neutral
difference equations with quasi-differences of the form $$ \Delta \left( r_{n}
\Delta \left( x_{n}+q_{n}x_{n-\tau}\right)\right)= a_{n}f(x_{n-\sigma})+b_n%, \
n\geq n_0 $$ with respect to $(q_n)$. For $q_n\to1$, $q_n\in(0,1)$ the standard
fixed point approach is not sufficed to get the existence of the bounded
solution, so we combine this method with an approximation technique to achieve
our goal. Moreover, for $p\ge 1$ and $\sup|q_n|<2^{1-p}$ using Krasnoselskii's
fixed point theorem we obtain sufficient conditions of the existence of the
solution which belongs to $l^p$ space.


title:
Approximate Inference for Time-varying Interactions and Macroscopic
  Dynamics of Neural Populations

abstract:
  The models in statistical physics such as an Ising model offer a convenient
way to characterize stationary activity of neural populations. Such stationary
activity of neurons may be expected for recordings from in vitro slices or
anesthetized animals. However, modeling activity of cortical circuitries of
awake animals has been more challenging because both spike-rates and
interactions can change according to sensory stimulation, behavior, or an
internal state of the brain. Previous approaches modeling the dynamics of
neural interactions suffer from computational cost; therefore, its application
was limited to only a dozen neurons. Here by introducing multiple analytic
approximation methods to a state-space model of neural population activity, we
make it possible to estimate dynamic pairwise interactions of up to 60 neurons.
More specifically, we applied the pseudolikelihood approximation to the
state-space model, and combined it with the Bethe or TAP mean-field
approximation to make the sequential Bayesian estimation of the model
parameters possible. The large-scale analysis allows us to investigate dynamics
of macroscopic properties of neural circuitries underlying stimulus processing
and behavior. We show that the model accurately estimates dynamics of network
properties such as sparseness, entropy, and heat capacity by simulated data,
and demonstrate utilities of these measures by analyzing activity of monkey V4
neurons as well as a simulated balanced network of spiking neurons.


title:
Low-Rank Covariance-Assisted Downlink Training and Channel Estimation
  for FDD Massive MIMO Systems

abstract:
  We consider the problem of downlink training and channel estimation in
frequency division duplex (FDD) massive MIMO systems, where the base station
(BS) equipped with a large number of antennas serves a number of single-antenna
users simultaneously. To obtain the channel state information (CSI) at the BS
in FDD systems, the downlink channel has to be estimated by users via downlink
training and then fed back to the BS. For FDD large-scale MIMO systems, the
overhead for downlink training and CSI uplink feedback could be prohibitively
high, which presents a significant challenge. In this paper, we study the
behavior of the minimum mean-squared error (MMSE) estimator when the channel
covariance matrix has a low-rank or an approximate low-rank structure. Our
theoretical analysis reveals that the amount of training overhead can be
substantially reduced by exploiting the low-rank property of the channel
covariance matrix. In particular, we show that the MMSE estimator is able to
achieve exact channel recovery in the asymptotic low-noise regime, provided
that the number of pilot symbols in time is no less than the rank of the
channel covariance matrix. We also present an optimal pilot design for the
single-user case, and an asymptotic optimal pilot design for the multi-user
scenario. Lastly, we develop a simple model-based scheme to estimate the
channel covariance matrix, based on which the MMSE estimator can be employed to
estimate the channel. The proposed scheme does not need any additional training
overhead. Simulation results are provided to verify our theoretical results and
illustrate the effectiveness of the proposed estimated covariance-assisted MMSE
estimator.


title:
A measurement of the calorimeter response to single hadrons and
  determination of the jet energy scale uncertainty using LHC Run-1
  $pp$-collision data with the ATLAS detector

abstract:
  A measurement of the calorimeter response to isolated charged hadrons in the
ATLAS detector at the LHC is presented. This measurement is performed with 3.2
nb$^{-1}$ of proton--proton collision data at $\sqrt{s}=7$ TeV from 2010 and
0.1 nb$^{-1}$ of data at $\sqrt{s}=8$ TeV from 2012. A number of aspects of the
calorimeter response to isolated hadrons are explored. After accounting for
energy deposited by neutral particles, there is a 5\% discrepancy in the
modelling, using Geant4 physics lists, of the calorimeter response to isolated
charged hadrons in the central calorimeter region. The description of the
response to anti-protons at low momenta is found to be improved with respect to
previous analyses. The electromagnetic and hadronic calorimeters are also
examined separately, and the detector simulation is found to describe the
response in the hadronic calorimeter well. The jet energy scale uncertainty and
correlations in scale between jets of different momenta are derived based on
these studies. The uncertainty is 2--5\% for jets with transverse momenta above
2 TeV, where this method provides the jet energy scale uncertainty for ATLAS.


title:
Modeling Improved Fuzzy and Sliding-Mode for Single-Phase Inverter as
  Controllers in an EPS

abstract:
  In the last decades, the applications of power inverter increased rapidly. As
a result, in spite of rectifier, an inverter with a high-power electronic
oscillator has capability to convert direct current (DC) into alternating
current (AC) in different forms. In this paper, a new fuzzy logic control (FLC)
is suggested to an improved modeling inverter of a single-phase voltage source
using LC filter and voltage sensor. Moreover, two sliding and fuzzy modes of
non-linear voltage inverter controller are simulated and compared. The results
proved the high efficiency and performance of the proposed method while reduce
total harmonic distortion (THD) under linear loading conditions as well. All
the data are applied on emergency power supply (EPS).


title:
The interstellar dust reservoir: SPICA's view on dust production and the
  interstellar medium in galaxies

abstract:
  Typical galaxies emit about one third of their energy in the infrared. The
origin of this emission reprocessed starlight absorbed by interstellar dust
grains and reradiated as thermal emission in the infrared. In particularly
dusty galaxies, such as starburst galaxies, the fraction of energy emitted in
the infrared can be as high as 90%. Dust emission is found to be an excellent
tracer of the beginning and end stages of a star's life, where dust is being
produced by post-main-sequence stars, subsequently added to the interstellar
dust reservoir, and eventually being consumed by star and planet formation.
This work reviews the current understanding of the size and properties of this
interstellar dust reservoir, by using the Large Magellanic Cloud as an example,
and what can be learned about the dust properties and star formation in
galaxies from this dust reservoir, using SPICA, building on previous work
performed with the Herschel and Spitzer Space Telescopes, as well as the
Infrared Space Observatory.


title: Limit theorems for the Zig-Zag process

abstract:
  Markov chain Monte Carlo methods provide an essential tool in statistics for
sampling from complex probability distributions. While the standard approach to
MCMC involves constructing discrete-time reversible Markov chains whose
transition kernel is obtained via the Metropolis- Hastings algorithm, there has
been recent interest in alternative schemes based on piecewise deterministic
Markov processes (PDMPs). One such approach is based on the Zig-Zag process,
introduced in Bierkens and Roberts (2016), which proved to provide a highly
scalable sampling scheme for sampling in the big data regime (Bierkens,
Fearnhead and Roberts (2016)). In this paper we study the performance of the
Zig-Zag sampler, focusing on the one-dimensional case. In particular, we
identify conditions under which a Central limit theorem (CLT) holds and
characterize the asymptotic variance. Moreover, we study the influence of the
switching rate on the diffusivity of the Zig-Zag process by identifying a
diffusion limit as the switching rate tends to infinity. Based on our results
we compare the performance of the Zig-Zag sampler to existing Monte Carlo
methods, both analytically and through simulations.


title:
Supersolid phases of dipolar fermions in a two-dimensional-lattice
  bilayer array

abstract:
  Supersolid phases as a result of a coexistence of superfluid and density
ordered checkerboard phases are predicted to appear in ultracold Fermi
molecules confined in a bilayer array of two-dimensional square optical
lattices. We demonstrate the existence of these phases within the inhomogeneous
mean-field approach. In particular, we show that tuning the interlayer
separation distance at a fixed value of the chemical potential produces
different fractions of superfluid, density ordered, and supersolid phases.


title: Spectroscopic signatures of molecular orbitals on a honeycomb lattice

abstract:
  A tendency to form benzene-like molecular orbitals has been recently shown to
be a common feature of the $4d$ and $5d$ transition metal oxides with a
honeycomb lattice. This tendency competes with other interactions such as the
spin-orbit coupling and Hubbard correlations, and can be partially or
completely suppressed. In the calculations, SrRu$_{2}$O$_{6}$ presents the
cleanest, so far, case of well-formed molecular orbitals, however, direct
experimental evidence for or against this proposition has been missing. In this
paper, we show that combined photoemission and optical studies can be used to
identify molecular orbitals in SrRu$_{2}$O$_{6}$. Symmetry-driven election
selection rules suppress optical transitions between certain molecular
orbitals, while photoemission and inverse photoemission measurements are
insensitive to them. Comparing the photoemission and optical conductivity
spectra one should be able to observe clear signatures of molecular orbitals.


title:
Effect of a magnetic field on massive star winds I: mass-loss and
  velocity for a dipole field

abstract:
  We generalize the Rigid-Field Hydrodynamic equations to accommodate arbitrary
magnetic field topologies, resulting in a new Arbitrary Rigid-Field
hydrodynamic (ARFHD) formalism. We undertake a critical point calculation of
the steady-state ARFHD equations with a CAK-type radiative acceleration and
determine the effects of a dipole magnetic field on the usual CAK mass-loss
rate and velocity structure. Enforcing the proper optically-thin limit for the
radiative line-acceleration is found to decrease both the mass-loss and wind
acceleration, while rotation boosts both properties. We define
optically-thin-correction and rotation parameters to quantify these effects on
the global mass-loss rate and develop scaling laws for the surface mass-flux as
a function of surface colatitude. These scaling laws are found to agree with
previous laws derived from magnetohydrodynamic simulations of magnetospheres.
The dipole magnetosphere velocity structure is found to differ from a global
beta-velocity law, which contradicts a central assumption of the
previously-developed XADM model of X-ray emission from magnetospheres.


title: Caveat on the Boltzmann distribution function use in biology

abstract:
  Sigmoid semilogarithmic functions with shape of Boltzmann equations, have
become extremely popular to describe diverse biological situations. Part of the
popularity is due to the easy avail- ability of software which fits Boltzmann
functions to data, without much knowledge of the fitting procedure or the
statistical properties of the parameters derived from the procedure. The
purpose of this paper is to explore the plasticity of the Boltzmann function to
fit data, some aspects of the optimization procedure to fit the function to
data and how to use this plastic function to differentiate the effect of
treatment on data and to attest the statistical significance of treatment
effect on the data.


title: Bounding the distance among longest paths in a connected graph

abstract:
  It is easy to see that in a connected graph any 2 longest paths have a vertex
in common. For k>=7, Skupien in [7] obtained a connected graph in which some k
longest paths have no common vertex, but every k-1 longest paths have a common
vertex. It is not known whether every 3 longest paths in a connected graph have
a common vertex and similarly for 4, 5, and 6 longest path. In [5] the authors
give an upper bound on distance among 3 longest paths in a connected graph. In
this paper we give a similar upper bound on distance between 4 longest paths
and also for k longest paths, in general.


title: Approximate solutions of scalar conservation laws

abstract:
  We study compactness properties of time-discrete and continuous time BGK-type
schemes for scalar conservation laws, in which microscopic interactions occur
only when the state of a system deviates significantly from an equilibrium
distribution. The threshold deviation, $\epsilon,$ is a parameter of the
problem. In the vanishing relaxation time limit we obtain solutions of a
conservation law in which flux is pointwisely close (of order $\epsilon$) to
the flux of the original equation and derive several other properties of such
solutions, including an example of approximate solution to a shock for Burger's
equation.


title:
Gibb's minimization principle for approximate solutions of scalar
  conservation laws

abstract:
  In this work we study variational properties of approximate solutions of
scalar conservation laws. Solutions of this type are described by a kinetic
equation which is similar to the kinetic representation of admissible weak
solutions due to Lions-Perthame-Tadmor, but also retain small scale
non-equilibrium behavior. We show that approximate solutions can be obtained
from a BGK-type equation with equilibrium densities satisfying Gibb's entropy
minimization principle.


title: A Unified Approach for Beam-to-Beam Contact

abstract:
  Existing beam contact formulations can be categorized in point contact models
that consider a discrete contact force at the closest point of the beams, and
line contact models that assume distributed contact forces. In this work, it
will be shown that line contact formulations provide accurate and robust
mechanical models in the range of small contact angles, whereas the
computational efficiency considerably decreases with increasing contact angles.
On the other hand, point contact formulations serve as sufficiently accurate
and very efficient models in the regime of large contact angles, while they are
not applicable for small contact angles as a consequence of non-unique closest
point projections. In order to combine the advantages of these basic
formulations, a novel all-angle beam contact (ABC) formulation is developed
that applies a point contact formulation for large contact angles and a
recently developed line contact formulation for small contact angles, the two
being smoothly connected by means of a variationally consistent model
transition. Based on a stringent analysis, two different transition laws are
investigated, optimal algorithmic parameters are suggested and conservation of
energy and momentum is shown. All configuration-dependent quantities are
consistently linearized, thus allowing for their application within implicit
time integration schemes. Furthermore, a step size control of the nonlinear
solution scheme that allows for large displacement increments per time step and
an efficient two-stage contact search based on dynamically adapted search
segments are proposed. A series of numerical test cases is analyzed in order to
verify the accuracy and consistency of the proposed contact model transition
regarding contact force distributions and conservation properties, but also for
quantifying the efficiency gains as compared to standard beam contact
formulations.


title: Sneutrino Inflation with $\alpha$-attractors

abstract:
  Sneutrino inflation employs the fermionic partners of the inflaton and
stabilizer field as right-handed neutrinos to realize the seesaw mechanism for
light neutrino masses. We show that one can improve the latest version of this
scenario and its consistency with the Planck data by embedding it in the theory
of cosmological $\alpha$-attractors.


title:
A support function of the weighted $L^2$ integrations on the superlevel
  sets of the weights

abstract:
  In this article, we establish a support function of the weighted $L^2$
integrations on the superlevel sets of the weights with optimal asymptoticity
near the positive infinity, which is an analogue of the truth of Demailly's
strong openness conjecture.


title: Earthquakes in cities revisited

abstract:
  During the last twenty years, a number of publications of
theoretical-numerical nature have appeared which come to the
apparently-reassuring conclusion that seismic motion on the ground in cities is
smaller than what this motion would be in the absence of the buildings (but for
the same underground and seismic load). Other than the fact that this finding
tells nothing about the motion within the buildings, it must be confronted with
the overwhelming empirical evidence (e.g, earthquakes in Sendai (2011),
Kathmandu (2015), Tainan City (2016), etc.) that shaking within buildings of a
city is often large enough to damage or even destroy these structures. I show,
on several examples, that theory can be reconciled with empirical evidence, and
suggest that the crucial subject of seismic response in cities is in need of
more thorough research.


title:
SO(8) Fermion Dynamical Symmetry and Strongly-Correlated Quantum Hall
  States in Monolayer Graphene

abstract:
  A formalism is presented for treating strongly-correlated graphene quantum
Hall states in terms of an SO(8) fermion dynamical symmetry that includes
pairing as well as particle--hole generators. The graphene SO(8) algebra is
isomorphic to an SO(8) algebra that has found broad application in nuclear
physics, albeit with physically very different generators, and exhibits a
strong formal similarity to SU(4) symmetries that have been proposed to
describe high-temperature superconductors. The well-known SU(4) symmetry of
quantum Hall ferromagnetism for single-layer graphene is recovered as one
subgroup of SO(8), but the dynamical symmetry structure associated with the
full set of SO(8) subgroup chains extends quantum Hall ferromagnetism and
allows analytical many-body solutions for a rich set of collective states
exhibiting spontaneously-broken symmetry that may be important for the
low-energy physics of graphene in strong magnetic fields. The SO(8) symmetry
permits a natural definition of generalized coherent states that correspond to
symmetry-constrained Hartree--Fock--Bogoliubov solutions, or equivalently a
microscopically-derived Ginzburg--Landau formalism, exhibiting the interplay
between competing spontaneously broken symmetries in determining the ground
state.


title:
Hopf invariants, topological complexity, and LS-category of the cofiber
  of the diagonal map for two-cell complexes

abstract:
  Let $X$ be a two-cell complex with attaching map $\alpha\colon S^q\to S^p$,
and let $C_X$ be the cofiber of the diagonal inclusion $X\to X\times X$. It is
shown that the topological complexity (${\rm TC}$) of $X$ agrees with the
Lusternik-Schnirelmann category (${\rm cat}$) of $C_X$ in the (almost stable)
range $q\leq2p-1$. In addition, the equality ${\rm TC}(X)={\rm cat}(C_X)$ is
proved in the (strict) metastable range $2p-1<q\leq3(p-1)$ under fairly mild
conditions by making use of the Hopf invariant techniques recently developed by
the authors in their study of the sectional category of arbitrary maps.


title: Vortex Laser at Exceptional Point

abstract:
  The optical vortices carrying orbital angular momentum (OAM) are commonly
generated by modulating the available conventional light beam. This article
shows that a micro-laser operates at the exceptional point (EP) of the
non-Hermitian quantum system can directly emit vortex laser with well-defined
OAM at will. Two gratings (the refractive index modulation and along azimuthal
direction and the grating protruding from the micro-ring cavity) modulate the
eigenmode of a micro-ring cavity to be a vortex laser mode. The phase-matching
condition ensures that we can tune the OAM of the vortex beam to be arbitrary
orders by changing the grating protruding from the micro-ring cavity while the
system is kept at EP. The results are obtained by analytical analysis and
confirmed by 3D full wave simulations.


title:
A Chandra X-ray study of the young star cluster NGC 6231: low-mass
  population and initial mass function

abstract:
  NGC6231 is a massive young star cluster, near the center of the Sco OB1
association. While its OB members are well studied, its low-mass population has
received little attention. We present high-spatial resolution Chandra ACIS-I
X-ray data, where we detect 1613 point X-ray sources. Our main aim is to
clarify global properties of NGC6231 down to low masses through a detailed
membership assessment, and to study the cluster stars' spatial distribution,
the origin of their X-ray emission, the cluster age and formation history, and
initial mass function. We use X-ray data, complemented by optical/IR data, to
establish cluster membership. The spatial distribution of different stellar
subgroups also provides highly significant constraints on cluster membership,
as does the distribution of X-ray hardness. We perform spectral modeling of
group-stacked X-ray source spectra. We find a large cluster population down to
~0.3 Msun (complete to ~1 Msun), with minimal non-member contamination, with a
definite age spread (1-8 Myrs) for the low-mass PMS stars. We argue that
low-mass cluster stars also constitute the majority of the few hundreds
unidentified X-ray sources. We find mass segregation for the most massive
stars. The fraction of circumstellar-disk bearing members is found to be ~5%.
Photoevaporation of disks under the action of massive stars is suggested by the
spatial distribution of the IR-excess stars. We also find strong Halpha
emission in 9% of cluster PMS stars. The dependence of X-ray properties on
mass, stellar structure, and age agrees with extrapolations based on other
young clusters. The cluster initial mass function, computed over ~2 dex in
mass, has a slope Gamma~-1.14. The total mass of cluster members above 1 Msun
is 2280 Msun, and the inferred total mass is 4380 Msun. We also study the
peculiar, hard X-ray spectrum of the Wolf-Rayet star WR79.


title:
Spin and charge susceptibilities of the two-orbital model within the
  cluster perturbation theory for Fe-based materials

abstract:
  Cluster perturbation theory is used to calculate band structure, spectral
functions, Fermi surface, and spin and charge susceptibilities for the
two-orbital model of iron pnictides with the on-site multiorbital Hubbard
interactions. Susceptibilities are calculated within the approximation
combining the cluster perturbation theory for the self-energy corrections and
the random-phase approximation (RPA) for the vertex renormalizations.
Calculations for the small values of Hubbard repulsion $U \leq 2$ confirm that
the rigid band approximation and RPA for the spin and charge susceptibilities
are suitable approaches for the case of weak interactions.


title: Cosmic Rays in a Galactic Breeze

abstract:
  Motivated by the discovery of the non-thermal Fermi bubble features both
below and above the Galactic plane, we investigate a scenario in which these
bubbles are formed through Galacto-centric outflow. Cosmic rays (CR) both
diffusing and advecting within a Galactic breeze outflow, interacting with the
ambient gas present, give rise to gamma-ray emission, providing an
approximately flat surface brightness profile of this emission, as observed.
Applying the same outflow profile further out within the disk, the resultant
effects on the observable CR spectral properties are determined. A hardening in
the spectra due to the competition of advective and diffusive propagation
within a particular energy range is noted, even in the limiting case of equal
CR diffusion coefficients in the disk and halo. It is postulated that this
hardening effect may relate to the observed hardening feature in the CR
spectrum at a rigidity of $\approx 200$ GV.


title: Exponentially fast convergence to (strict) equilibrium via hedging

abstract:
  Motivated by applications to data networks where fast convergence is
essential, we analyze the problem of learning in generic N-person games that
admit a Nash equilibrium in pure strategies. Specifically, we consider a
scenario where players interact repeatedly and try to learn from past
experience by small adjustments based on local - and possibly imperfect -
payoff information. For concreteness, we focus on the so-called "hedge" variant
of the exponential weights algorithm where players select an action with
probability proportional to the exponential of the action's cumulative payoff
over time. When players have perfect information on their mixed payoffs, the
algorithm converges locally to a strict equilibrium and the rate of convergence
is exponentially fast - of the order of
$\mathcal{O}(\exp(-a\sum_{j=1}^{t}\gamma_{j}))$ where $a>0$ is a constant and
$\gamma_{j}$ is the algorithm's step-size. In the presence of uncertainty,
convergence requires a more conservative step-size policy, but with high
probability, the algorithm remains locally convergent and achieves an
exponential convergence rate.


title:
The DLVHEX System for Knowledge Representation: Recent Advances (System
  Description)

abstract:
  The DLVHEX system implements the HEX-semantics, which integrates answer set
programming (ASP) with arbitrary external sources. Since its first release ten
years ago, significant advancements were achieved. Most importantly, the
exploitation of properties of external sources led to efficiency improvements
and flexibility enhancements of the language, and technical improvements on the
system side increased user's convenience. In this paper, we present the current
status of the system and point out the most important recent enhancements over
early versions. While existing literature focuses on theoretical aspects and
specific components, a bird's eye view of the overall system is missing. In
order to promote the system for real-world applications, we further present
applications which were already successfully realized on top of DLVHEX. This
paper is under consideration for acceptance in Theory and Practice of Logic
Programming.


title: Law of Iterated Logarithm for random graphs

abstract:
  A milestone in Probability Theory is the law of the iterated logarithm (LIL),
proved by Khinchin and independently by Kolmogorov in the 1920s, which asserts
that for iid random variables $\{t_i\}_{i=1}^{\infty}$ with mean $0$ and
variance $1$
  $$ \Pr \left[ \limsup_{n\rightarrow \infty} \frac{ \sum_{i=1}^n t_i
}{\sigma_n \sqrt {2 \log \log n }} =1 \right] =1 . $$
  In this paper we prove that LIL holds for various functionals of random
graphs and hypergraphs models. We first prove LIL for the number of copies of a
fixed subgraph $H$. Two harder results concern the number of global objects:
perfect matchings and Hamiltonian cycles. The main new ingredient in these
results is a large deviation bound, which may be of independent interest. For
random $k$-uniform hypergraphs, we obtain the Central Limit Theorem (CLT) and
LIL for the number of Hamilton cycles.


title:
Avalanches and force drops in displacement-driven compression of porous
  glasses

abstract:
  Similarities between force-driven compression experiments of porous materials
and earthquakes have been recently proposed. In this manuscript, we measure the
acoustic emission during displacement-driven compression of a porous glass. The
energy of acoustic-emission events shows that the failure process exhibits
avalanche scale-invariance and therefore follows the Gutenberg-Richter law. The
resulting exponents do not exhibit significant differences with respect the
force-driven case. Furthermore, the force exhibits an avalanche-type behaviour
for which the force drops are power-law distributed and correlated with the
acoustic emission events.


title: Drop splashing is independent of substrate wetting

abstract:
  A liquid drop impacting a dry solid surface with sufficient kinetic energy
will splash, breaking apart into numerous secondary droplets. This phenomenon
shows many similarities to forced wetting, including the entrainment of air at
the contact line. Because of these similarities and the fact that forced
wetting has been shown to depend on the wetting properties of the surface,
existing theories predict splashing to depend on wetting properties as well.
However, using high-speed interference imaging we observe that at high
capillary numbers wetting properties have no effect on splashing for various
liquid-surface combinations. Additionally, by fully resolving the Navier-Stokes
equations at length and time scales inaccessible to experiments, we find that
the shape and motion of the air-liquid interface at the contact line at the
edge of the droplet are independent of wettability. We use these findings to
evaluate existing theories and to compare splashing with forced wetting.


title:
Gamma-ray emission from PSR J0007+7303 using 7 years of Fermi Large Area
  Telescope observations

abstract:
  Based on more than seven years of Fermi Large Area Telescope (LAT) Pass 8
data, we report on a detailed analysis of the bright gamma-ray pulsar (PSR)
J0007+7303. We confirm that PSR J0007+7303 is significantly detected as a point
source also during the off-peak phases with a TS value of 262 ($\sim$ 16
$\sigma$). In the description of PSR J0007+7303 off-peak spectrum, a power law
with an exponential cutoff at 2.7$\pm$1.2$\pm$1.3 GeV (the first/second
uncertainties correspond to statistical/systematic errors) is preferred over a
single power law at a level of 3.5 $\sigma$. The possible existence of a cutoff
hints at a magnetospheric origin of the emission. In addition, no extended
gamma-ray emission is detected compatible with either the supernova remnant
(CTA 1) or the very high energy (> 100 GeV) pulsar wind nebula. A flux upper
limit of 6.5$\times$10$^{-12}$ erg cm$^{-2}$ s$^{-1}$ in the 10-300 GeV energy
range is reported, for an extended source assuming the morphology of the
VERITAS detection. During on-peak phases, a sub-exponential cutoff is
significantly preferred ($\sim$11 $\sigma$) for representing the spectral
energy distribution, both in the phase-averaged and in the phase-resolved
spectra. Three glitches are detected during the observation period and we found
no flux variability at the time of the glitches or in the long-term behavior.
We also report the discovery of a previously unknown gamma-ray source in the
vicinity of PSR J0007+7303, Fermi J0020+7328, which we associate with the z =
1.781 quasar S5 0016+73. A concurrent analysis of this source is needed to
correctly characterize the behavior of CTA 1 and it is also presented in the
paper.


title: Pseudocontact shifts from mobile spin labels

abstract:
  This paper presents a detailed analysis of the pseudocontact shift (PCS)
field induced by a mobile spin label that is viewed as a probability density
distribution with an associated effective magnetic susceptibility anisotropy.
It is demonstrated that non-spherically-symmetric density can lead to
significant deviations from the commonly used point dipole approximation for
PCS. Analytical and numerical solutions are presented for the general partial
differential equation that describes the non-point case. It is also
demonstrated that it is possible, with some reasonable approximations, to
reconstruct paramagnetic centre probability distributions from the experimental
PCS data.


title:
Exchange interaction-driven dynamic nuclear polarization in Mn-doped
  InGaAs/GaAs quantum dots

abstract:
  We investigated optical spin orientation and dynamic nuclear polarization
(DNP) in individual self-assembled InGaAs/GaAs quantum dots (QDs) doped by a
single Mn atom, a magnetic impurity providing a neutral acceptor A$^0$ with an
effective spin $J=1$. We find that the spin of an electron photo-created in
such a quantum dot can be efficiently oriented by a quasi-resonant
circularly-polarized excitation. For the electron spin levels which are made
quasi-degenerate by a magnetic field compensating the exchange interaction
$\Delta_e$ with A$^0$, there is however a full depolarization due the
anisotropic part of the exchange. Still, in most studied QDs, the spin
polarized photo-electrons give rise to a pronounced DNP which grows with a
longitudinal magnetic field until a critical field where it abruptly vanishes.
For some QDs, several replica of such DNP sequence are observed at different
magnetic fields. This striking behavior is qualitatively discussed as a
consequence of different exchange interactions experienced by the electron,
driving the DNP rate via the energy cost of electron-nucleus spin flip-flops.