title: Spectral properties of unimodular lattice triangulations

abstract:
  Random unimodular lattice triangulations have been recently used as an
embedded random graph model, which exhibit a crossover behaviour between an
ordered, large-world and a disordered, small-world behaviour. Using the ergodic
Pachner flips that transform such triangulations into another and an energy
functional that corresponds to the degree distribution variance, Markov chain
Monte-Carlo simulations can be applied to study these graphs. Here, we consider
the spectra of the adja cency and the Laplacian matrix as well as the algebraic
connectivity and the spectral radius. Power law dependencies on the system size
can clearly be identified and compared to analytical solutions for periodic
ground states. For random triangulations we find a qualitative agreement of the
spectral properties with well-known random graph models. In the microcanonical
ensemble analytical approximations agree with numerical simulations. In the
canonical ensemble a crossover behaviour can be found for the algebraic
connectivity and the spectral radius, thus combining large-world and
small-world behavior in one model. The considered spectral properties can be
applied to transport problems on triangulation graphs and the crossover
behaviour allows a tuning of important transport quantities.


title: Can we close the Bohr-Einstein quantum debate?

abstract:
  Recent experiments allowed concluding that Bell-type inequalities are indeed
violated thus it is important to understand what it means and how can we
explain the existence of strong correlations between outcomes of distant
measurements. Do we have to announce that: Einstein was wrong, Nature is
nonlocal and nonlocal correlations are produced due to the quantum magic and
emerge, somehow, from outside space time? Fortunately such conclusions are
unfounded because if supplementary parameters describing measuring instruments
are correctly incorporated in a theoretical model then Bell-type inequalities
may not be proven .We construct a simple probabilistic model explaining these
correlations in a locally causal way. In our model measurement outcomes are
neither predetermined nor produced in irreducibly random way. We explain in
detail why, contrary to the general belief; an introduction of setting
dependent parameters does not restrict experimenters' freedom of choice. Since
the violation of Bell-type inequalities does not allow concluding that Nature
is nonlocal and that quantum theory is complete thus the Bohr-Einstein quantum
debate may not be closed. The continuation of this debate is not only important
for a better understanding of Nature but also for various practical
applications of quantum phenomena.


title: Band-Passes and Long Virtual Knot Concordance

abstract:
  Every classical knot is band-pass equivalent to the unknot or the trefoil.
The band-pass class of a knot is a concordance invariant. Every ribbon knot,
for example, is band-pass equivalent to the unknot. Here we introduce the long
virtual knot concordance group $\mathscr{VC}$. It is shown that for every
concordance class $[K] \in \mathscr{VC}$, there is a $J \in [K]$ that is not
band-pass equivalent to $K$ and an $L \in [K]$ that is not band-pass equivalent
to either the long unknot or any long trefoil. This is accomplished by proving
that $v_{2,1}+v_{2,2} \pmod 2$ is a band-pass invariant but not a concordance
invariant of long virtual knots, where $v_{2,1}$ and $v_{2,2}$ generate the
degree two Polyak group for long virtual knots.


title:
Ergodic measures on compact metric spaces for isometric actions by
  inductively compact groups

abstract:
  We obtain a partial converse of Vershik's description of ergodic probability
measures on a compact metric space with respect to an isometric action by an
inductively compact group. This allows us to identify, in this setting, the set
of ergodic probability measures with the set of weak limit points of orbital
measures.


title: The Sobolev moment problem and Jordan dilations

abstract:
  Moment problems and orthogonal polynomials, both meant in a single real
variable, belong to the oldest problems in Classical Analysis. They have been
developing for over a century in two parallel, mostly independent streams.
During the last 20 years a rapid advancement of polynomials orthogonal in
Sobolev space has been noticed; their moment counterpart seems to be not paid
enough attention as it deserves. In this paper we intend to resume the theme
and open the door for further, deeper study of the problem.


title: On the origins of polarization holes in Bok globules

abstract:
  Context. Polarimetric observations of Bok globules frequently show a decrease
in the degree of polarization towards their central dense regions (polarization
holes). This behaviour is usually explained with increased disalignment owing
to high density and temperature, or insufficient angular resolution of a
possibly complex magnetic field structure.
  Aims. We investigate whether a significant decrease in polarized emission of
dense regions in Bok globules is possible under certain physical conditions.
For instance, we evaluate the impact of optical depth effects and various
properties of the dust phase.
  Methods. We use radiative transfer modelling to calculate the temperature
structure of an analytical Bok globule model and simulate the polarized thermal
emission of elongated dust grains. For the alignment of the dust grains, we
consider a magnetic field and include radiative torque and internal alignment.
  Results. Besides the usual explanations, selected conditions of the
temperature and density distribution, the dust phase and the magnetic field are
also able to significantly decrease the polarized emission of dense regions in
Bok globules. Taking submm/mm grains and typical column densities of existing
Bok globules into consideration, the optical depth is high enough to decrease
the degree of polarization by up to {\Delta}P~10%. If limited to the densest
regions, dust grain growth to submm/mm size and accumulated graphite grains
decrease the degree of polarization by up to {\Delta}P~10% and {\Delta}P~5%,
respectively. However, the effect of the graphite grains occurs only if they do
not align with the magnetic field.


title:
A canonical rate-independent model of geometrically linear isotropic
  gradient plasticity with isotropic hardening and plastic spin accounting for
  the Burgers vector

abstract:
  In this paper we propose a canonical variational framework for
rate-independent phenomenological geometrically linear gradient plasticity with
plastic spin. The model combines the additive decomposition of the total
distortion into non-symmetric elastic and plastic distortions, with a defect
energy contribution taking account of the Burgers vector through a dependence
only on the dislocation density tensor Curl(p) giving rise to a non-symmetric
nonlocal backstress, and isotropic hardening response only depending on the
accumulated equivalent plastic strain. The model is fully isotropic and
satisfies linearized gauge-invariance conditions, i.e., only true
state-variables appear. The model satisfies also the principle of maximum
dissipation which allows to show existence for the weak formulation. For this
result, a recently introduced Korn's inequality for incompatible tensor fields
is necessary. Uniqueness is shown in the class of strong solutions. For
vanishing energetic length scale, the model reduces to classical
elasto-plasticity with symmetric plastic strain sym(p) and standard isotropic
hardening.


title: Stochastic systems with memory and jumps

abstract:
  Stochastic systems with memory naturally appear in life science, economy, and
finance. We take the modelling point of view of stochastic functional delay
equations and we study these structures when the driving noises admit jumps.
Our results concern existence and uniqueness of strong solutions, estimates for
the moments and the fundamental tools of calculus, such as the It\^o formula.
We study the robustness of the solution to the change of noises. Specifically,
we consider the noises with infinite activity jumps versus an adequately
corrected Gaussian noise. The study is presented in two different frameworks:
we work with random variables in infinite dimensions, where the values are
considered either in an appropriate $L^p$-type space or in the space of
c\`adl\`ag paths. The choice of the value space is crucial from the modelling
point of view as the different settings allow for the treatment of different
models of memory or delay. Our techniques involve tools of infinite dimensional
calculus and the stochastic calculus via regularization.


title: Component Based Modeling of Ultrasound Signals

abstract:
  This work proposes a component based model for the raw ultrasound signals
acquired by the transducer elements. Based on this approach, before undergoing
the standard digital processing chain, every sampled raw signal is first
decomposed into a smooth background signal and a strong reflectors component.
The decomposition allows for a suited processing scheme to be adjusted for each
component individually. We demonstrate the potential benefit of this approach
in image enhancement by suppressing side lobe artifacts, and in improvement of
digital data compression. Applying our proposed processing schemes to real
cardiac ultrasound data, we show that by separating the two components and
compressing them individually, over twenty-fold reduction of the data size is
achieved while retaining the image contents.


title: WKB approach to pair creation in spacetime-dependent fields

abstract:
  Besides tunneling in static potential landscapes, for example, the
Wentzel-Kramers-Brillouin (WKB) approach is a powerful nonperturbative
approximation tool to study particle creation due to time-dependent background
fields, such as cosmological particle production or the Sauter-Schwinger
effect, i.e., electron-positron pair creation in a strong electric field.
However, our understanding of particle creation processes in background fields
depending on both space and time is rather incomplete. In order to venture into
this direction, we propose a generalization of the WKB method to truly
spacetime-dependent fields and apply it to the case of a spacetime-dependent
mass.


title: Gland Segmentation in Colon Histology Images: The GlaS Challenge Contest

abstract:
  Colorectal adenocarcinoma originating in intestinal glandular structures is
the most common form of colon cancer. In clinical practice, the morphology of
intestinal glands, including architectural appearance and glandular formation,
is used by pathologists to inform prognosis and plan the treatment of
individual patients. However, achieving good inter-observer as well as
intra-observer reproducibility of cancer grading is still a major challenge in
modern pathology. An automated approach which quantifies the morphology of
glands is a solution to the problem. This paper provides an overview to the
Gland Segmentation in Colon Histology Images Challenge Contest (GlaS) held at
MICCAI'2015. Details of the challenge, including organization, dataset and
evaluation criteria, are presented, along with the method descriptions and
evaluation results from the top performing methods.


title: Secondary fast reconnecting instability in the sawtooth crash

abstract:
  In this work we consider magnetic reconnection in thin current sheets with
both resistive and electron inertia effects. When the current sheet is produced
by a primary instability of the internal kink type, the analysis of secondary
instabilities indicates that reconnection proceeds on a time scale much shorter
than the primary instability characteristic time. In the case of a sawtooth
crash, non-collisional physics becomes important above a value of the Lundquist
number which scales like S ~ (R/d_e)^{12/5}, in terms of the tokamak major
radius R and of the electron skin depth d_e. This value is commonly achieved in
present day devices. As collisionality is further reduced, the characteristic
rate increases, approaching Alfv\'enic values when the primary instability
approaches the collisionless regime.


title: Exciton Radiative Lifetime in Transition Metal Dichalcogenide Monolayers

abstract:
  We have investigated the exciton dynamics in transition metal dichalcogenide
mono-layers using time-resolved photoluminescence experiments performed with
optimized time-resolution. For MoSe2 monolayers, we measure
$\tau_{rad}=1.8\pm0.2$ ps that we interpret as the intrinsic radiative
recombination time. Similar values are found for WSe2 mono-layers. Our detailed
analysis suggests the following scenario: at low temperature (T $\leq$ 50 K),
the exciton oscillator strength is so large that the entire light can be
emitted before the time required for the establishment of a thermalized exciton
distribution. For higher lattice temperatures, the photoluminescence dynamics
is characterized by two regimes with very different characteristic times. First
the PL intensity drops drastically with a decay time in the range of the
picosecond driven by the escape of excitons from the radiative window due to
exciton- phonon interactions. Following this first non-thermal regime, a
thermalized exciton population is established gradually yielding longer
photoluminescence decay times in the nanosecond range. Both the exciton
effective radiative recombination and non-radiative recombination channels
including exciton-exciton annihilation control the latter. Finally the
temperature dependence of the measured exciton and trion dynamics indicates
that the two populations are not in thermodynamical equilibrium.


title: Methods used by WHO to estimate the Global burden of TB disease

abstract:
  This paper describes methodological details used by WHO in 2015 to estimate
TB incidence, prevalence and mortality. Incidence and mortality are
disaggregated by HIV status, age and sex. Methods to derive MDR-TB burden
indicators are detailed. Four main methods were used to derive incidence: (i)
case notification data combined with expert opinion about case detection gaps
(120 countries representing 51% of global incidence); (ii) results from
national TB prevalence surveys (19 countries, 46% of global incidence); (iii)
notifications in high-income countries adjusted by a standard factor to account
for under-reporting and underdiagnosis (73 countries, 3% of global incidence)
and (iv) capture-recapture modelling (5 countries, 0.5% of global incidence).
Prevalence was obtained from results of national prevalence surveys in 21
countries, representing 69% of global prevalence). In other countries,
prevalence was estimated from incidence and disease duration. Mortality was
obtained from national vital registration systems of mortality surveys in 129
countries (43% of global HIV-negative TB mortality). In other countries,
mortality was derived indirectly from incidence and case fatality ratio.


title:
Fast iterative method with a second order implicit difference scheme for
  time-space fractional convection-diffusion equations

abstract:
  In this paper we want to propose practical numerical methods to solve a class
of initial-boundary problem of time-space fractional convection-diffusion
equations (TSFCDEs). To start with, an implicit difference method based on
two-sided weighted shifted Gr\"{u}nwald formulae is proposed with a discussion
of the stability and convergence. We construct an implicit difference scheme
(IDS) and show that it converges with second order accuracy in both time and
space. Then, we develop fast solution methods for handling the resulting system
of linear equation with the Toeplitz matrix. The fast Krylov subspace solvers
with suitable circulant preconditioners are designed to deal with the resulting
Toeplitz linear systems. Each time level of these methods reduces the memory
requirement of the proposed implicit difference scheme from $\mathcal{O}(N^2)$
to $\mathcal{O}(N)$ and the computational complexity from $O(N^3)$ to $O(N\log
N)$ in each iterative step, where $N$ is the number of grid nodes. Extensive
numerical example runs show the utility of these methods over the traditional
direct solvers of the implicit difference methods, in terms of computational
cost and memory requirements.


title: Smoothing and non-smoothing via a flow tangent to the Ricci flow

abstract:
  We study a transformation of metric measure spaces introduced by Gigli and
Mantegazza consisting in replacing the original distance with the length
distance induced by the transport distance between heat kernel measures. We
study the smoothing effect of this procedure in two important examples.
Firstly, we show that in the case of some Euclidean cones, a singularity
persists at the apex. Secondly, we generalize the construction to a
sub-Riemannian manifold, namely the Heisenberg group, and show that it
regularizes the space instantaneously to a smooth Riemannian manifold.


title:
Error analysis of linear optics measurements via turn-by-turn beam
  position data in circular accelerators

abstract:
  Many advanced techniques have been developed, tested and implemented in the
last decades in almost all circular accelerators across the world to measure
the linear optics. However, the greater availability and accuracy of beam
diagnostics and the ever better correction of linear magnetic lattice
imperfections (beta beating at 1% level and coupling at 0.1%) are reaching what
seems to be the intrinsic accuracy and precision of different measurement
techniques. This paper aims to highlight and quantify, when possible, the
limitations of one standard method, the harmonic analysis of turn-by-turn beam
position data. To this end, new analytic formulas for the evaluation of lattice
parameters modified by focusing errors are derived. The unexpected conclusion
of this study is that for the ESRF storage ring (and possibly for any third
generation light source operating at ultra-low coupling and with similar
diagnostics), measurement and correction of linear optics via orbit beam
position data are to be preferred to the analysis of turn-by-turn data.


title: Cacti with Extremal PI Index

abstract:
  The vertex PI index $PI(G) = \sum_{xy \in E(G)} [n_{xy}(x) + n_{xy}(y)]$ is a
distance-based molecular structure descriptor, where $n_{xy}(x)$ denotes the
number of vertices which are closer to the vertex $x$ than to the vertex $y$
and which has been the considerable research in computational chemistry dating
back to Harold Wiener in 1947. A connected graph is a cactus if any two of its
cycles have at most one common vertex. In this paper, we completely determine
the extremal graphs with the largest and smallest vertex PI indices among all
the cacti. As a consequence, we obtain the sharp bounds with corresponding
extremal cacti and extend a known result.


title: Visualizing "Fermi arcs" in the Weyl semimetal TaAs

abstract:
  One of the hallmarks of Weyl semi-metals is the existence of unusual
topological surface states known as 'Fermi arcs' [1-3]. The formation of these
states is guaranteed by the existence of bulk Weyl points with opposite
chirality. Tantalum Arsenide (TaAs) [4-9], a member of the newly discovered
family of Weyl semi-metals [4,5], harbors a host of non-topological ('trivial')
surface states overlapping in energy with the predicted 12 'Fermi arcs'. This
overlap poses a major challenge in identifying the signatures of the arcs [10].
Here we harness the inherently distinct spatial structure of trivial and Fermi
arc states to visualize the Fermi arcs for the first time using scanning
tunneling microscopy. We do so in four distinct ways, each of which highlights
a different aspect of their unusual nature. We reveal their relatively
isotropic scattering signature, their energy dispersion and its relation to the
bulk Weyl points, their deep bulk penetration relative to that of
non-topological surface states and their weak coupling to the atomic structure.
The latter is obtained by accounting for the spatial structure of the Bloch
wavefunction and its effect on the scattering properties of the electrons off
lattice defects in general. It thus provides a novel analysis tool for the
spectroscopic characterization of electronic wavefunctions using scanning
tunneling microscopy.


title:
Dual Smoothing and Level Set Techniques for Variational Matrix
  Decomposition

abstract:
  We focus on the robust principal component analysis (RPCA) problem, and
review a range of old and new convex formulations for the problem and its
variants. We then review dual smoothing and level set techniques in convex
optimization, present several novel theoretical results, and apply the
techniques on the RPCA problem. In the final sections, we show a range of
numerical experiments for simulated and real-world problems.


title: Kernel-based Tests for Joint Independence

abstract:
  We investigate the problem of testing whether $d$ random variables, which may
or may not be continuous, are jointly (or mutually) independent. Our method
builds on ideas of the two variable Hilbert-Schmidt independence criterion
(HSIC) but allows for an arbitrary number of variables. We embed the
$d$-dimensional joint distribution and the product of the marginals into a
reproducing kernel Hilbert space and define the $d$-variable Hilbert-Schmidt
independence criterion (dHSIC) as the squared distance between the embeddings.
In the population case, the value of dHSIC is zero if and only if the $d$
variables are jointly independent, as long as the kernel is characteristic.
Based on an empirical estimate of dHSIC, we define three different
non-parametric hypothesis tests: a permutation test, a bootstrap test and a
test based on a Gamma approximation. We prove that the permutation test
achieves the significance level and that the bootstrap test achieves pointwise
asymptotic significance level as well as pointwise asymptotic consistency
(i.e., it is able to detect any type of fixed dependence in the large sample
limit). The Gamma approximation does not come with these guarantees; however,
it is computationally very fast and for small $d$, it performs well in
practice. Finally, we apply the test to a problem in causal discovery.


title: Redividing the Cake

abstract:
  The paper considers fair allocation of resources that are already allocated
in an unfair way. This setting requires a careful balance between the fairness
considerations and the rights of the present owners.
  The paper presents re-division algorithms that attain various trade-off
points between fairness and ownership rights, in various settings differing in
the geometric constraints on the allotments: (a) no geometric constraints; (b)
connectivity -- the cake is a one-dimensional interval and each piece must be a
contiguous interval; (c) rectangularity -- the cake is a two-dimensional
rectangle or rectilinear polygon and the pieces should be rectangles; (d)
convexity -- the cake is a two-dimensional convex polygon and the pieces should
be convex.
  These re-division algorithms have implications on another problem: the
price-of-fairness -- the loss of social welfare caused by fairness
requirements. Each algorithm implies an upper bound on the price-of-fairness
with the respective geometric constraints.


title: A $\gamma\gamma$ Collider for the 750 GeV Resonant State

abstract:
  Recent data collected by ATLAS and CMS at 13 TeV collision energy of the LHC
indicate the existence of a new resonant state $\phi$ with a mass of 750 GeV
decaying into two photons $\gamma\gamma$. The properties of $\phi$ should be
studied further at the LHC and also future colliders. Since only $\phi \to
\gamma\gamma$ decay channel has been measured, one of the best ways to extract
more information about $\phi$ is to use a $\gamma\gamma$ collider to produce
$\phi$ at the resonant energy. In this work we show how a $\gamma\gamma$
collider helps to verify the existence of $\phi$ and to provide some of the
most important information about the properties of $\phi$, such as branching
fractions of $\phi\to V_1V_2$. Here $V_i$ can be $\gamma$, $Z$, or $W^\pm$. We
also show that by studying angular distributions of the final $\gamma$'s in
$\gamma\gamma \to \phi \to \gamma\gamma$, one can obtain crucial information
about whether this state is a spin-0 or a spin-2 state.


title:
Effects of an impermeable wall in dissipative dynamics of saturated
  porous media

abstract:
  A phase transition model for porous media in consolidation is studied. The
model is able to describe the phenomenon of fluid-segregation during the
consolidation process, i.e., the coexistence of two phases differing from fluid
content inside the porous medium under static load. Considering pure Darcy
dissipation, the dynamics is described by a Cahn-Hilliard-like system of
partial differential equations (PDE). The goal, here, is to study the dynamics
of the formation of stationary fluid-rich bubbles. The evolution of the strain
and fluid density profiles of the porous medium is analyzed in two physical
situation: fluid free to flow through the boundaries of the medium and fluid
flow prevented at one of the two boundaries. Morover, an analytic result on the
position of the interface between the two phases is provided.


title:
Boundary-Finite Element discretization of time dependent acoustic
  scattering by elastic obstacles with piezoelectric behavior

abstract:
  A coupled BEM/FEM formulation for the transient interaction between an
acoustic field and a piezoelectric scatterer is proposed. The scattered part of
the acoustic wave is represented in terms of retarded layer potentials while
the elastic displacement and electric potential are treated variationally. This
results in an integro-differential system. Well posedness of a general Galerkin
semi-discretization in space of the problem is shown in the Laplace domain and
translated into explicit stability bounds in the time domain. Trapezoidal-Rule
and BDF2 Convolution Quadrature are used in combination with matching time
stepping for time discretization. Second order convergence is proven for the
BDF2-based method. Numerical experiments are provided for BDF2 and Trapezoidal
Rule based time evolution.


title:
Width of the exotic $X_b(5568)$ state through its strong decay to
  $B_s^{0} \pi^{+}$

abstract:
  The width of the newly observed exotic state $X_b(5568)$ is calculated via
its dominant strong decay to $% B_s^{0} \pi^{+}$ using the QCD sum rule method
on the light-cone in conjunction with the soft-meson approximation. To this
end, the vertex $X_{b}B_{s}\pi$ is studied and the strong coupling
$g_{X_{b}B_{s}\pi}$ is computed employing for $X_b(5568)$ state the
interpolating diquark-antidiquark current of the
$[su][\overline{b}\overline{d}]$ type. The obtained prediction for the decay
width of $X_b(5568)$ is confronted and a nice agreement found with the
experimental data of the D0 Collaboration.


title: T Pyxidis: Death by a Thousand Novae

abstract:
  We report a 20-year campaign to track the 1.8 hour photometric wave in the
recurrent nova T Pyxidis, using the global telescope network of the Center for
Backyard Astrophysics. During 1996-2011, that wave was highly stable in
amplitude and waveform, resembling the orbital wave commonly seen in supersoft
binaries. The period, however, was found to increase on a timescale
P/P-dot=3x10^5 years. This suggests a mass transfer rate in quiescence of
~10^-7 M_sol/yr, in substantial agreement with the accretion rate based on the
star's luminosity. This is ~2000x greater than is typical for cataclysmic
variables of that orbital period. During the post-eruption quiescence
(2012-2016), the star continued on its merry but mysterious way - similar
luminosity, similar P/P-dot (2.4x10^5 years).
  The orbital signal became vanishingly weak (<0.003 mag) near maximum light of
the 2011 eruption. By day 170 of the eruption, near V=11, the orbital signal
reappeared with an amplitude of 0.005 mag. It then gradually strengthened to
its normal 0.08 mag amplitude, as the star declined to its "quiescent"
magnitude of 15.7. During the ~1 year of invisibility and low amplitude, the
orbital signal had increased in period by 0.0054(7)%. This is probably a
measure of the mass ejected in the nova outburst. For a plausible choice of
binary parameters, that mass is at least 3x10^-5 M_sol, and probably more. This
represents >300 years of accretion at the pre-outburst rate, but the time
between outbursts was only 45 years. Thus the erupting white dwarf seems to
have ejected at least 6x more mass than it accreted. If this eruption is
typical, the white dwarf must be eroding, rather than growing, in mass. Unless
the present series of eruptions is a short-lived episode, the binary dynamics
appear to be a mutual suicide pact between the eroding white dwarf and the
low-mass secondary, excited ... . (etc., abstract continues)


title:
NC plane waves, Casimir effect and flux tube potential with L\"uscher
  terms

abstract:
  We analyze plane waves in a model of quantum mechanics in a three dimensional
noncommutative (NC) space $R^3_{\lambda}$. Signature features of NC models are
impossibility of probing distances smaller than a certain length scale
{\lambda} and a presence of natural energetic cut-off at energy scale of order
$1/{\lambda}^2$ (in convenient units). We analyze consequences of such
restrictions on a 1 dimensional Casimir effect. The result shows resemblance to
flux tube potential for quark-antiquark pairs and to effective bosonic string
theories with L\"uscher terms. Such behavior might effect the radius of
possible compact (fuzzy) dimensions.


title: RWebData: A High-Level Interface to the Programmable Web

abstract:
  The rise of the programmable web offers new opportunities for the empirically
driven social sciences. The access, compilation and preparation of data from
the programmable web for statistical analysis can, however, involve substantial
up-front costs for the practical researcher. The R-package RWebData provides a
high-level framework that allows data to be easily collected from the
programmable web in a format that can directly be used for statistical analysis
in R (R Core Team 2013) without bothering about the data's initial format and
nesting structure. It was developed specifically for users who have no
experience with web technologies and merely use R as a statistical software.
The core idea and methodological contribution of the package are the
disentangling of parsing web data and mapping them with a generic algorithm
(independent of the initial data structure) to a flat table-like
representation. This paper provides an overview of the high-level functions for
R-users, explains the basic architecture of the package, and illustrates the
implemented data mapping algorithm.


title: Coordinates for the Universal Moduli Space of Holomorphic Vector Bundles

abstract:
  In this paper we provide two ways of constructing complex coordinates on the
moduli space of pairs of a Riemann surface and a stable holomorphic vector
bundle centred around any such pair. We compute the transformation between the
coordinates to second order at the center of the coordinates. We conclude that
they agree to second order, but not to third order at the center.


title:
Hybrid Feedback Path Following for Robotic Walkers via Bang-Bang Control
  Actions

abstract:
  We show a control algorithm to guide a robotic walking assistant along a
planned path. The control strategy exploits the electromechanical brakes
mounted on the back wheels of the walker. In order to reduce the hardware
requirements we adopt a Bang Bang approach relying of four actions (with
saturated value for the braking torques).When the platform is far away from the
path, we execute an approach phase in which the walker converges toward the
platform with a specified angle. When it comes in proximity of the platform,
the control strategy switches to a path tracking mode, which uses the four
control actions to converge toward the path with an angle which is a function
of the state. This way it is possible to control the vehicle in feedback,
secure a gentle convergence of the user to the planned path and her steady
progress towards the destination.


title:
Jeans instability criterion from the viewpoint of non-gaussian
  statistics

abstract:
  In this Letter we have derived the Jeans length in the context of the
Kaniadakis statistics. We have compared this result with the Jeans length
obtained in the non-extensive Tsallis statistics and discussed the main
differences between these two models. We have also obtained the kappa-sound
velocity. Finally, we have applied the results obtained here to analyze an
astrophysical system.


title: Bayesian Quantile Regression for Ordinal Longitudinal Data

abstract:
  Since the pioneering work by Koenker and Bassett (1978), quantile regression
models and its applications have become increasingly popular and important for
research in many areas. In this paper, a random effects ordinal quantile
regression model is proposed for analysis of longitudinal data with ordinal
outcome of interest. An efficient Gibbs sampling algorithm was derived for
fitting the model to the data based on a location scale mixture representation
of the skewed double exponential distribution. The proposed approach is
illustrated using simulated data and a real data example. This is the first
work to discuss quantile regression for analysis of longitudinal data with
ordinal outcome.


title: Production and Interactions of Hyperons and Hypernuclei

abstract:
  The production of strangeness on the nucleon and hyperon and hypernuclear
production in heavy ion collisions at relativistic energies and in antiproton
annihilation on nuclei is discussed. The reaction process is described by
transport theory with focus on $S=-2$ channels and a comparison of different
model interactions. The interactions of hyperons in nuclear matter is
investigated in a novel SU(3) approach. An outlook to the $S=-3$ sector and
$\Omega^-$ physics is given.


title: Surprises in numerical expressions of physical constants

abstract:
  In science, as in life, `surprises' can be adequately appreciated only in the
presence of a null model, what we expect a priori. In physics, theories
sometimes express the values of dimensionless physical constants as
combinations of mathematical constants like pi or e. The inverse problem also
arises, whereby the measured value of a physical constant admits a
`surprisingly' simple approximation in terms of well-known mathematical
constants. Can we estimate the probability for this to be a mere coincidence,
rather than an inkling of some theory? We answer the question in the most naive
form.


title:
Efficient 3-D Placement of an Aerial Base Station in Next Generation
  Cellular Networks

abstract:
  Agility and resilience requirements of future cellular networks may not be
fully satisfied by terrestrial base stations in cases of unexpected or
temporary events. A promising solution is assisting the cellular network via
low-altitude unmanned aerial vehicles equipped with base stations, i.e.,
drone-cells. Although drone-cells provide a quick deployment opportunity as
aerial base stations, efficient placement becomes one of the key issues. In
addition to mobility of the drone-cells in the vertical dimension as well as
the horizontal dimension, the differences between the air-to-ground and
terrestrial channels cause the placement of the drone-cells to diverge from
placement of terrestrial base stations. In this paper, we first highlight the
properties of the dronecell placement problem, and formulate it as a 3-D
placement problem with the objective of maximizing the revenue of the network.
After some mathematical manipulations, we formulate an equivalent
quadratically-constrained mixed integer non-linear optimization problem and
propose a computationally efficient numerical solution for this problem. We
verify our analytical derivations with numerical simulations and enrich them
with discussions which could serve as guidelines for researchers, mobile
network operators, and policy makers.


title:
Real-space cluster dynamical mean-field approach to the Falicov-Kimball
  model: An alloy-analogy approach

abstract:
  It is long known that the best single-site coherent potential approximation
(CPA) falls short of describing Anderson localization (AL). Here, we study a
binary alloy disorder (or equivalently, a spinless Falicov-Kimball (FK)) model
and construct a dominantly analytic cluster extension that treats intra-cluster
($1/d$, $d$=spatial dimension) correlations exactly. We find that, in general,
the irreducible two-particle vertex exhibits clear non-analyticities before the
band-splitting transition of the Hubbard type occurs, signaling onset of an
unusual type of localization at strong coupling. Using time-dependent response
to a sudden local quench as a diagnostic, we find that the long-time wave
function overlap changes from a power-law to an anomalous form at strong
coupling, lending additional support to this idea. Our results also imply such
novel "strong" localization in the equivalent FK model, the simplest
interacting fermion system.


title: MIMO-NOMA Design for Small Packet Transmission in the Internet of Things

abstract:
  A feature of the Internet of Things (IoT) is that some users in the system
need to be served quickly for small packet transmission. To address this
requirement, a new multiple-input multiple-output non-orthogonal multiple
access (MIMO-NOMA) scheme is designed in this paper, where one user is served
with its quality of service (QoS) requirement strictly met, and the other user
is served opportunistically by using the NOMA concept. The novelty of this new
scheme is that it confronts the challenge that most existing MIMO-NOMA schemes
rely on the assumption that users' channel conditions are different, a strong
assumption which may not be valid in practice. The developed precoding and
detection strategies can effectively create a significant difference between
the users' effective channel gains, and therefore the potential of NOMA can be
realized even if the users' original channel conditions are similar. Analytical
and numerical results are provided to demonstrate the performance of the
proposed MIMO-NOMA scheme.


title: Tattooing and the Tattoo Number of Graphs

abstract:
  Consider a network $D$ of pipes which have to be cleaned using some cleaning
agents, called brushes, assigned to some vertices. The minimum number of
brushes required for cleaning the network $D$ is called its brush number. The
tattooing of a simple connected directed graph $D$ is a particular type of the
cleaning in which an arc are coloured by the colour of the colour-brush
transiting it and the tattoo number of $D$ is a corresponding derivative of
brush numbers in it. Tattooing along an out-arc of a vertex $v$ may proceed if
a minimum set of colour-brushes is allocated (primary colours) or combined with
those which have arrived (including colour blends) together with mutation of
permissible new colour blends, has cardinality greater than or equal to
$d^+_G(v)$.


title:
Spectral duality in elliptic systems, six-dimensional gauge theories and
  topological strings

abstract:
  We consider Dotsenko-Fateev matrix models associated with compactified
Calabi-Yau threefolds. They can be constructed with the help of explicit
expressions for refined topological vertex, i.e. are directly related to the
corresponding topological string amplitudes. We describe a correspondence
between these amplitudes, elliptic and affine type Selberg integrals and gauge
theories in five and six dimensions with various matter content. We show that
the theories of this type are connected by spectral dualities, which can be
also seen at the level of elliptic Seiberg-Witten integrable systems. The most
interesting are the spectral duality between the XYZ spin chain and the
Ruijsenaars system, which is further lifted to self-duality of the double
elliptic system.


title: A High Braking Index for a Pulsar

abstract:
  We present a phase-coherent timing solution for PSR J1640-4631, a young 206
ms pulsar using X-ray timing observations taken with NuSTAR. Over this timing
campaign, we have measured the braking index of PSR J1640-4631 to be n =
3.15+/-0.03. Using a series of simulations, we argue that this unusually high
braking index is not due to timing noise, but is intrinsic to the pulsar's
spin-down. We cannot, however, rule out contamination due to an unseen glitch
recovery, although the recovery timescale would have to be longer than most yet
observed. If this braking index is eventually proven to be stable, it
demonstrates that pulsar braking indices greater than 3 are allowed in nature,
hence other physical mechanisms such as mass or magnetic quadrupoles are
important in pulsar spin-down. We also present a 3-sigma upper limit on the
pulsed flux at 1.4 GHz of 0.018 mJy.


title:
Revealing the ultrafast light-to-matter energy conversion before heat
  diffusion in a layered Dirac semimetal

abstract:
  There is still no general consensus on how one can describe the
out-of-equilibrium phenomena in matter induced by an ultrashort light pulse. We
investigate the pulse-induced dynamics in a layered Dirac semimetal SrMnBi2 by
pump-and-probe photoemission spectroscopy. At ~<1 ps, the electronic recovery
slowed upon increasing the pump power. Such a bottleneck-type slowing is
expected in a two-temperature model (TTM) scheme, although opposite trends have
been observed to date in graphite and in cuprates. Subsequently, an
unconventional power-law cooling took place at ~100 ps, indicating that spatial
heat diffusion is still ill defined at ~100 ps. We identify that the successive
dynamics before the emergence of heat diffusion is a canonical realization of a
TTM scheme. Criteria for the applicability of the scheme is also provided.


title: A Graph-Based Semantics Workbench for Concurrent Asynchronous Programs

abstract:
  A number of novel programming languages and libraries have been proposed that
offer simpler-to-use models of concurrency than threads. It is challenging,
however, to devise execution models that successfully realise their
abstractions without forfeiting performance or introducing unintended
behaviours. This is exemplified by SCOOP---a concurrent object-oriented
message-passing language---which has seen multiple semantics proposed and
implemented over its evolution. We propose a "semantics workbench" with fully
and semi-automatic tools for SCOOP, that can be used to analyse and compare
programs with respect to different execution models. We demonstrate its use in
checking the consistency of semantics by applying it to a set of representative
programs, and highlighting a deadlock-related discrepancy between the principal
execution models of the language. Our workbench is based on a modular and
parameterisable graph transformation semantics implemented in the GROOVE tool.
We discuss how graph transformations are leveraged to atomically model
intricate language abstractions, and how the visual yet algebraic nature of the
model can be used to ascertain soundness.


title: Cherenkov Radiation with Massive, CPT-violating Photons

abstract:
  The source of CPT-violation in the photon sector of the Standard Model
Extension arises from a Chern-Simons-like contribution that involves a coupling
to a fixed background vector field $k_{AF}^\mu$. These Lorentz- and
CPT-violating photons have well-known theoretical issues that arise from
missing states at low momenta when $k_{AF}^\mu$ is timelike. In order to make
the theory consistent, a tiny mass for the photon can be introduced, well below
current experimental bounds. The implementation of canonical quantization can
then be implemented as in the CPT-preserving case by using the St\"uckelberg
mechanism. We explicitly construct a covariant basis of properly-normalized
polarization vectors at fixed three-momentum satisfying the momentum space
field equations, in terms of which the vector field can be expanded. As an
application of the theory, we calculate the Cherenkov radiation rate for the
case of purely timelike $k_{AF}^\mu$, and find a radiation rate at high
energies that has a contribution that does not depend on the mass used to
regulate the photons.


title: Modeling non-thermal emission from stellar bow shocks

abstract:
  Runaway O- and early B-type stars passing throughout the interstellar medium
at supersonic velocities and characterized by strong stellar winds may produce
bow shocks that can serve as particle acceleration sites. Previous theoretical
models predict the production of high energy photons by non-thermal radiative
processes, but their efficiency is still debated. We aim to test and explain
the possibility of emission from the bow shocks formed by runaway stars
traveling through the interstellar medium by using previous theoretical models.
We apply our model to AE Aurigae, the first reported star with an X-ray
detected bow shock, to BD+43 3654, in which the observations failed in
detecting high energy emission, and to the transition phase of a supergiant
star in the late stages of its life.From our analysis, we confirm that the
X-ray emission from the bow shock produced by AE Aurigae can be explained by
inverse Compton processes involving the infrared photons of the heated dust. We
also predict low high energy flux emission from the bow shock produced by BD+43
3654, and the possibility of high energy emission from the bow shock formed by
a supergiant star during the transition phase from blue to red supergiant.Bow
shock formed by different type of runaway stars are revealed as a new possible
source of high energy photons in our neighbourhood.


title:
Gribov process advected by the synthetic compressible velocity ensemble:
  Renormalization Group Approach

abstract:
  The direct bond percolation process (Gribov process) is studied in the
presence of irrotational velocity fluctuations with long-range correlations.
The perturbative renormalization group is employed in order to analyze the
effects of finite correlation time on the long-time behavior of the phase
transition between an active and an ab- sorbing state. The calculation is
performed to the one-loop order. Stable fixed points of the renormalization
group and their regions of stability are obtained within the three-parameter
$(\epsilon,y,\eta)$- expansion. Different regimes corresponding to the rapid-
change limit and frozen velocity field are discussed.


title:
Why does Monte Carlo fail to work properly in high-dimensional
  optimization problems?

abstract: The paper proposes an answer to the question formulated in the title.


title: Chromatic number of ordered graphs with forbidden ordered subgraphs

abstract:
  It is well-known that the graphs not containing a given graph H as a subgraph
have bounded chromatic number if and only if H is acyclic. Here we consider
ordered graphs, i.e., graphs with a linear ordering on their vertex set, and
the function f(H) = sup{chi(G) | G in Forb(H)} where Forb(H) denotes the set of
all ordered graphs that do not contain a copy of H. If H contains a cycle, then
as in the case of unordered graphs, f(H) is infinity. However, in contrast to
the unordered graphs, we describe an infinite family of ordered forests H with
infinite f(H). An ordered graph is crossing if there are two edges uv and u'v'
with u < u' < v < v'. For connected crossing ordered graphs H we reduce the
problem of determining whether f(H) is finite to a family of so-called
monotonically alternating trees. For non-crossing H we prove that f(H) is
finite if and only if H is acyclic and does not contain a copy of any of the
five special ordered forests on four or five vertices, which we call bonnets.
For such forests H, we show that f(H) <= 2^|V(H)| and that f(H) <= 2|V(H)|-3 if
H is connected.


title:
Effect of electron-hole separation on optical properties of individual
  Cd(Se,Te) Quantum Dots

abstract:
  Cd(Se,Te) Quantum Dots (QD) in ZnSe barrier typically exhibit a very high
spectral density, which precludes investigation of single dot
photoluminescence. We design, grow and study individual Cd(Se,Te)/ZnSe QDs of
low spectral density of emission lines achieved by implementation of a
Mn-assisted epitaxial growth. We find an unusually large variation of
exciton-biexciton energy difference (3 meV $\leq$ $\Delta \mathrm{E_{X-XX}}$
$\leq$ 26 meV) and of exciton radiative recombination rate in the statistics of
QDs. We observe a strong correlation between the exciton-biexciton energy
difference, exciton recombination rate, splitting between dark and bright
exciton, and additionally the exciton fine structure splitting $\delta_1$ and
Land\'e factor. Above results indicate that values of the $\delta_1$ and of the
Land\'e factor in the studied QDs are dictated primarily by the electron and
hole respective spatial shift and wavefunctions overlap, which vary from dot to
dot due to a different degree of localization of electrons and holes in,
respectively, CdSe and CdTe rich QD regions.


title: Photon merging and splitting in electromagnetic field inhomogeneities

abstract:
  We investigate photon merging and splitting processes in inhomogeneous,
slowly varying electromagnetic fields. Our study is based on the three-photon
polarization tensor following from the Heisenberg-Euler effective action. We
put special emphasis on deviations from the well-known constant field results,
also revisiting the selection rules for these processes. In the context of
high-intensity laser facilities, we analytically determine compact expressions
for the number of merged/split photons as obtained in the focal spots of
intense laser beams. For the parameter range of a typical petawatt class laser
system as pump and a terawatt class laser as probe, we provide estimates for
the numbers of signal photons attainable in an actual experiment. The
combination of frequency upshifting, polarization dependence and scattering off
the inhomogeneities renders photon merging an ideal signature for the
experimental exploration of nonlinear quantum vacuum properties.


title:
Measurement of two-photon exchange effect by comparing elastic $e^\pm p$
  cross sections

abstract:
  [Background] The electromagnetic form factors of the proton measured by
unpolarized and polarized electron scattering experiments show a significant
disagreement that grows with the squared four momentum transfer ($Q^{2}$).
Calculations have shown that the two measurements can be largely reconciled by
accounting for the contributions of two-photon exchange (TPE). TPE effects are
not typically included in the standard set of radiative corrections since
theoretical calculations of the TPE effects are highly model dependent, and,
until recently, no direct evidence of significant TPE effects has been
observed.
  [Purpose] We measured the ratio of positron-proton to electron-proton
elastic-scattering cross sections in order to determine the TPE contribution to
elastic electron-proton scattering and thereby resolve the proton electric form
factor discrepancy.
  [Methods] We produced a mixed simultaneous electron-positron beam in
Jefferson Lab's Hall B by passing the 5.6 GeV primary electron beam through a
radiator to produce a bremsstrahlung photon beam and then passing the photon
beam through a convertor to produce electron/positron pairs. The mixed
electron-positron (lepton) beam with useful energies from approximately 0.85 to
3.5 GeV then struck a 30-cm long liquid hydrogen (LH$_2$) target located within
the CEBAF Large Acceptance Spectrometer (CLAS). By detecting both the scattered
leptons and the recoiling protons we identified and reconstructed elastic
scattering events and determined the incident lepton energy. A detailed
description of the experiment is presented.


title: Convergence of Limited Communications Gradient Methods

abstract:
  Distributed optimization increasingly plays a central role in economical and
sustainable operation of cyber-physical systems. Nevertheless, the complete
potential of the technology has not yet been fully exploited in practice due to
communication limitations posed by the real-world infrastructures. This work
investigates fundamental properties of distributed optimization based on
gradient methods, where gradient information is communicated using limited
number of bits. In particular, a general class of quantized gradient methods
are studied where the gradient direction is approximated by a finite
quantization set. Sufficient and necessary conditions are provided on such a
quantization set to guarantee that the methods minimize any convex objective
function with Lipschitz continuous gradient and a nonempty and bounded set of
optimizers. A lower bound on the cardinality of the quantization set is
provided, along with specific examples of minimal quantizations. Convergence
rate results are established that connect the fineness of the quantization and
the number of iterations needed to reach a predefined solution accuracy.
Generalizations of the results to a relevant class of constrained problems
using projections are considered. Finally, the results are illustrated by
simulations of practical systems.


title: Finite element approximation for the fractional eigenvalue problem

abstract:
  The purpose of this work is to study a finite element method for finding
solutions to the eigenvalue problem for the fractional Laplacian. We prove that
the discrete eigenvalue problem converges to the continuous one and we show the
order of such convergence. Finally, we perform some numerical experiments and
compare our results with previous work by other authors.


title:
Localized energy associated with Bianchi-Type VI universe in $f(R)$
  theory of gravity

abstract:
  In the present work, focusing on one of the most popular problems in modern
gravitation theories, we consider generalized Lanndau-Liftshitz energy-momentum
relation to calculate energy distribution of the Bianchi-Type VI spacetime in
$f(R)$ gravity. Additionally, the results are specified by using some
well-known $f(R)$-gravity models.


title: Nakamaye's theorem on complex manifolds

abstract:
  We discuss Nakamaye's Theorem and its recent extension to compact complex
manifolds, together with some applications.


title: An example of the Rvachev function method

abstract:
  We present a Rvachev function method with the Chebysev collocation for the
stability analysis of fluid flow. The strategy is to construct an approximate
solution that satisfies all boundary conditions exactly. As an example, we
consider the stability problem of the two-dimensional flow of an incompressible
viscous liquid near a circular cylinder. The results coincide well with the
reference data. The method is simpler than the widely used spectral/hp element
method, in particular because it does not require mesh generation, and the
collocation algorithm does not handle the boundary conditions or any geometric
information.


title: Generating a perfect quantum optical vortex

abstract:
  In this article we introduce a novel quantum state, the perfect quantum
optical vortex state which exhibits a highly localised distribution along a
ring in the quadrature space. We examine its nonclassical properties using the
Wigner function and the negativity volume. Such a quantum state can be a useful
resource for quantum information processing and communication.


title:
Exploiting nodes symmetries to control synchronization and consensus
  patterns in multiagent systems

abstract:
  We present new conditions to obtain synchronization and consensus patterns in
complex network systems. The key idea is to exploit symmetries of the nodes'
vector fields to induce a desired synchronization/consensus pattern, where
nodes are clustered in different groups each converging towards a different
synchronized evolution. We show that the new conditions we present offer a
systematic methodology to design a distributed network controller able to drive
a network of interest towards a desired synchronization/consensus pattern.


title:
Systematic investigation of projectile fragmentation using beams of
  unstable B and C isotopes

abstract:
  Background: Models describing nuclear fragmentation and fragmentation-fission
deliver important input for planning nuclear physics experiments and future
radioactive ion beam facilities. These models are usually benchmarked against
data from stable beam experiments. In the future, two-step fragmentation
reactions with exotic nuclei as stepping stones are a promising tool to reach
the most neutron-rich nuclei, creating a need for models to describe also these
reactions.
  Purpose: We want to extend the presently available data on fragmentation
reactions towards the light exotic region on the nuclear chart. Furthermore, we
want to improve the understanding of projectile fragmentation especially for
unstable isotopes.
  Method: We have measured projectile fragments from 10,12-18C and 10-15B
isotopes colliding with a carbon target. These measurements were all performed
within one experiment, which gives rise to a very consistent dataset. We
compare our data to model calculations.
  Results: One-proton removal cross sections with different final neutron
numbers (1pxn) for relativistic 10,12-18C and 10-15B isotopes impinging on a
carbon target. Comparing model calculations to the data, we find that EPAX is
not able to describe the data satisfactorily. Using ABRABLA07 on the other
hand, we find that the average excitation energy per abraded nucleon needs to
be decreased from 27 MeV to 8.1 MeV. With that decrease ABRABLA07 describes the
data surprisingly well.
  Conclusions: Extending the available data towards light unstable nuclei with
a consistent set of new data have allowed for a systematic investigation of the
role of the excitation energy induced in projectile fragmentation. Most
striking is the apparent mass dependence of the average excitation energy per
abraded nucleon. Nevertheless, this parameter, which has been related to
final-state interactions, requires further study.


title:
The $\alpha$-Modulation Transform: Admissibility, Coorbit Theory and
  Frames of Compactly Supported Functions

abstract:
  The $\alpha$-modulation transform is a time-frequency transform generated by
square-integrable representations of the affine Weyl-Heisenberg group modulo
suitable subgroups. In this paper we prove new conditions that guarantee the
admissibility of a given window function. We also show that the generalized
coorbit theory can be applied to this setting, assuming specific regularity of
the windows. This then yields canonical constructions of Banach frames and
atomic decompositions in $\alpha$-modulation spaces. In particular, we prove
the existence of compactly supported (in time domain) vectors that are
admissible and satisfy all conditions within the coorbit machinery, which
considerably go beyond known results.


title: The Diameters of Network-flow Polytopes satisfy the Hirsch Conjecture

abstract:
  We solve a problem in the combinatorics of polyhedra motivated by the network
simplex method. We show that the Hirsch conjecture holds for the diameter of
the graphs of all network-flow polytopes, in particular the diameter of a
network-flow polytope for a network with $n$ nodes and $m$ arcs is never more
than $m+n-1$. A key step to prove this is to show the same result for classical
transportation polytopes.


title: A Characterization of Gorenstein Planar graphs

abstract:
  We prove that a planar graph is Gorenstein if and only if its independence
complex is Eulerian.


title: Graded and Geometric Parabolic Induction for Category $\mathcal{O}$

abstract:
  We prove that the parabolic induction functor on BGG-category $\mathcal{O}$
associated to a complex reductive Lie algebra is gradable, that is, lifts to
graded category $\mathcal{O}$ as constructed by Beilinson-Ginzburg-Soergel.
Graded category $\mathcal{O}$ is equivalent to a category of stratified mixed
Tate motives on a corresponding flag variety as recently defined by
Soergel-Wendt. The graded version of parabolic induction is induced by a
geometric parabolic induction functor we construct on the level of stratified
mixed Tate motives. We also describe the effect of parabolic induction on the
level of Soergel modules.


title:
Turbulence-generated proton-scale structures in the terrestrial
  magnetosheath

abstract:
  Recent results of numerical magnetohydrodynamic simulations suggest that in
collisionless space plasmas turbulence can spontaneously generate thin current
sheets. These coherent structures can partially explain intermittency and the
non-homogenous distribution of localized plasma heating in turbulence. In this
Letter Cluster multi-point observations are used to investigate the
distribution of magnetic field discontinuities and the associated small-scale
current sheets in the terrestrial magnetosheath downstream of a quasi-parallel
bow shock. It is shown experimentally, for the first time, that the strongest
turbulence generated current sheets occupy the long tails of probability
distribution functions (PDFs) associated with extremal values of magnetic field
partial derivatives. During the analyzed one hour long time interval, about a
hundred strong discontinuities, possibly proton-scale current sheets were
observed.


title:
Characterization of threshold functions: state of the art, some new
  contributions and open problems

abstract:
  This paper has a twofold scope. The first one is to clarify and put in
evidence the isomorphic character of two theories developed in quite different
fields: on one side, threshold logic, on the other side, simple games. One of
the main purposes in both theories is to determine when a simple game is
representable as a weighted game, which allows a very compact and easily
comprehensible representation. Deep results were found in threshold logic in
the sixties and seventies for this problem. However, game theory has taken the
lead and some new results have been obtained for the problem in the last two
decades. The second and main goal of this paper is to provide some new results
on this problem and propose several open questions and conjectures for future
research. The results we obtain depend on two significant parameters of the
game: the number of types of equivalent players and the number of types of
shift-minimal winning coalitions.


title: Equidivisible pseudovarieties of semigroups

abstract:
  We give a complete characterization of pseudovarieties of semigroups whose
finitely generated relatively free profinite semigroups are equidivisible.
Besides the pseudovarieties of completely simple semigroups, they are precisely
the pseudovarieties that are closed under Mal'cev product on the left by the
pseudovariety of locally trivial semigroups. A further characterization which
turns out to be instrumental is as the non-completely simple pseudovarieties
that are closed under two-sided Karnofsky-Rhodes expansion.


title: Completely decomposable Jacobian varieties in new genera

abstract:
  We present a new technique to study Jacobian variety decompositions using
subgroups of the automorphism group of the curve and the corresponding
intermediate covers. In particular, this new method allows us to produce many
new examples of genera for which there is a curve with completely decomposable
Jacobian. These examples greatly extend the list given by Ekedahl and Serre of
genera containing such curves, and provide more evidence for a positive answer
to two questions they asked. Additionally, we produce new examples of families
of curves, all of which have completely decomposable Jacobian varieties. These
families relate to questions about special subvarieties in the moduli space of
principally polarized abelian varieties.


title:
Impact of initial models and variable accretion rates on the
  pre-main-sequence evolution of massive and intermediate-mass stars and the
  early evolution of HII regions

abstract:
  Massive star formation requires the accretion of gas at high rate while the
star is already bright. Its actual luminosity depends sensitively on the
stellar structure. We compute pre-main-sequence tracks for massive and
intermediate-mass stars with variable accretion rates and study the evolution
of stellar radius, effective temperature and ionizing luminosity, starting at
$2\,M_\odot$ with convective or radiative structures. The radiative case shows
a much stronger swelling of the protostar for high accretion rates than the
convective case. For radiative structures, the star is very sensitive to the
accretion rate and reacts quickly to accretion bursts, leading to considerable
changes in photospheric properties on timescales as short as 100 - 1000 yr. The
evolution for convective structures is much less influenced by the
instantaneous accretion rate, and produces a monotonically increasing ionizing
flux that can be many orders of magnitude smaller than in the radiative case.
For massive stars, it results in a delay of the HII region expansion by up to
10,000 yr. In the radiative case, the HII region can potentially be engulfed by
the star during the swelling, which never happens in the convective case. We
conclude that the early stellar structure has a large impact on the radiative
feedback during the pre-main-sequence evolution of massive protostars and
introduces an important uncertainty that should be taken into account. Because
of their lower effective temperatures, our convective models may hint at a
solution to an observed discrepancy between the luminosity distribution
functions of massive young stellar objects and compact HII regions.


title: Band Gap Engineering of Two-Dimensional Nitrogene

abstract:
  In our previous study, we have predicted the novel two-dimensional honeycomb
monolayers of pnictogen. In particular, the structure and properties of the
honeycomb monolayer of nitrogen, which we call nitrogene, are very unusual. In
this paper, we make an in-depth investigation of its electronic structure. We
find that the band structure of nitrogene can be engineered in several ways:
controlling the stacking of monolayers, application of biaxial tensile strain,
and application of perpendicular electric field. The band gap of nitrogene is
found to decrease with the increasing number of layers. The perpendicular
electric field can also reduce the band gap when it is larger than 0.18V/
{\AA}, and the gap closes at 0.35V/ {\AA}. A nearly linear dependence of the
gap on the electric field is found during the process. Application of biaxial
strain can decrease the band gap as well, and eventually closes the gap. After
the gap-closing, we find six inequivalent Dirac points in the Brillouin zone
under the strain between 17% and 28%, and the nitrogene monolayer becomes a
Dirac semimetal. These findings suggest that the electronic structure of
nitrogene can be modified by several techniques, which makes it a promising
candidate for electronic devices.


title: Finite F-type and F-abundant modules

abstract:
  In this note we introduce and study basic properties of two types of modules
over a commutative noetherian ring $R$ of positive prime characteristic. The
first is the category of modules of finite $F$-type. These objects include
reflexive ideals representing torsion elements in the divisor class group of
$R$. The second class is what we call $F$-abundant modules. These include, for
example, the ring $R$ itself and the canonical module when $R$ has positive
splitting dimension. We prove various facts about these two categories and how
they are related, for example that $\mathrm{Hom}_R(M,N)$ is maximal
Cohen-Macaulay when $M$ is of finite $F$-type and $N$ is $F$-abundant, plus
some extra (but necessary) conditions. Our methods allow us to extend previous
results by Patakfalvi-Schwede, Yao and Watanabe. They also afford a deeper
understanding of these objects, including complete classifications in many
cases of interest, such as complete intersections and invariant subrings.


title: How much radioactive nickel does ASASSN-15lh require?

abstract:
  The discovery of the most luminous supernova ASASSN-15lh triggered a
shock-wave in the supernova community. The three possible mechanisms proposed
for the majority of other superluminous supernovae do not produce a realistic
physical model for this particular supernova. In the present study we show the
limiting luminosity available from a nickel-powered pair-instability supernova.
We computed a few exotic nickel-powered explosions with a total mass of nickel
up to 1500 solar masses. We used the hydrostatic configurations prepared with
the GENEVA and MESA codes, and the STELLA radiative-transfer code for following
the explosion of these models. We show that 1500 solar masses of radioactive
nickel is needed to power a luminosity of 2x10^45 erg/s. The resulting light
curve is very broad and incompatible with the shorter ASASSN-15lh time-scale.
This rules out a nickel-powered origin of ASASSN-15lh. In addition, we derive a
simple peak luminosity - nickel mass relation from our data, which may serve to
estimate of nickel mass from observed peak luminosities.


title:
Projection based model order reduction methods for the estimation of
  vector-valued variables of interest

abstract:
  We propose and compare goal-oriented projection based model order reduction
methods for the estimation of vector-valued functionals of the solution of
parameter-dependent equations. The first projection method is a generalization
of the classical primal-dual method to the case of vector-valued variables of
interest. We highlight the role played by three reduced spaces: the
approximation space and the test space associated to the primal variable, and
the approximation space associated to the dual variable. Then we propose a
Petrov-Galerkin projection method based on a saddle point problem involving an
approximation space for the primal variable and an approximation space for an
auxiliary variable. A goal-oriented choice of the latter space, defined as the
sum of two spaces, allows us to improve the approximation of the variable of
interest compared to a primal-dual method using the same reduced spaces. Then,
for both approaches, we derive computable error estimates for the
approximations of the variable of interest and we propose greedy algorithms for
the goal-oriented construction of reduced spaces. The performance of the
algorithms are illustrated on numerical examples and compared to standard (non
goal-oriented) algorithms.


title: Status and perspectives of neutrino magnetic moments

abstract:
  Basic theoretical and experimental aspects of neutrino magnetic moments are
reviewed, including the present best upper bounds from reactor experiments and
astrophysics. An interesting effect of neutrino spin precession and
oscillations induced by the background matter transversal current or
polarization is also discussed.


title:
The $\omega$-SQUIPT: phase-engineering of Josephson topological
  materials

abstract:
  Multi-terminal superconducting Josephson junctions based on the proximity
effect offer the bright opportunity to tailor non trivial quantum states in
nanoscale weak-links. These structures can realize exotic topologies in
multidimensions as, for example, artificial topological superconductors able to
support Majorana bound states, and pave the way to emerging quantum
technologies and future quantum information schemes. Here, we report the first
realization of a three-terminal Josephson interferometer based on a proximized
nanosized weak-link. Our tunneling spectroscopy measurements reveal transitions
between gapped (i.e., insulating) and gapless (i.e., conducting) states, those
being controlled by the phase configuration of the three superconducting leads
connected to the junction. We demonstrate the $topological$ nature of these
transitions: a gapless state necessarily occurs between two gapped states of
different topological index, very much like the interface between two
insulators of different topology is necessarily conducting. The topological
numbers characterizing such gapped states are given by superconducting phase
windings over the two loops forming the Josephson interferometer. Since these
gapped states cannot be transformed to one another continuously withouth
passing through a gapless condition, these are topologically $protected$. Our
observation of the gapless state is pivotal for enabling phase engineering of
more sophisticated artificial topological materials realizing Weyl points or
the anomalous Josephson effect.


title:
Shear-banding and Taylor-Couette instability in thixotropic yield stress
  fluids

abstract:
  In the present work, we study the flow of thixotropic yield stress fluids
between two concentric cylinders. In order to take into account the thixotropy,
the constitutive relation uses a structural parameter which is driven by a
kinetic equation. Here, the Houska's model is considered. Depending on the
breakdown rate of the structural parameter, localization or shear-banding are
observed. We show that for fragile structures, a shear-banding flow may be
observed although for stronger structures, only localisation of the flow is
observed such as in Bingham fluids. Physical explanations of the shear-banding
discussed by several authors in the literature highlight that the shear-banding
may be associated with a discontinuity into the structure of the material and a
non-monotonic evolution of the stress according to the constitutive relation
with the strain rate. Solving numerically the flow, we show that such a
rheological model based on the existence of a structural parameter is able to
predict shear-banding. Moreover, the consequences of the thixotropy on the
linear stability of the azimuthal flow is studied in a large range of
parameters. Although the thixotropy allows shear banding for the base flow, it
does not modify fundamentaly the stability of the Couette flow compared to a
simple yield stress fluid. The apparent shear-thinning behaviour depends on the
thixotropic parameters of the fluid and the results about the onset of the
Taylor vortices in shear-thinning fluids are retrieved. Nevertheless, the
shear-banding modifies the stratification of the viscosity in the flowing zone
such that the critical conditions are mainly driven by the width of the flowing
region.


title:
The Decomposition Formula and Stationary Measures for Stochastic
  Lotka-Volterra Systems with Applications to Turbulent Convection

abstract:
  Motivated by the work of Busse et al. [6] on turbulent convection in a
rotating layer, we exploit the long-run behavior for stochastic Lotka-Volterra
(LV) systems both in pull-back trajectory and in stationary measure. It is
proved stochastic decomposition formula describing the relation between
solutions of stochastic and deterministic LV systems and stochastic Logistic
equation. By virtue of this formula, it is verified that every pull-back omega
limit set is an omega limit set for deterministic LV systems multiplied by the
random equilibrium of the stochastic Logistic equation. This formula is used to
derive the existence of a stationary measure, its support and ergodicity. We
prove the tightness for the set of stationary measures and the invariance for
their weak limits as the noise intensity vanishes, whose supports are contained
in the Birkhoff center.
  The developed theory is successfully utilized to completely classify three
dimensional competitive stochastic LV systems into $37$ classes. Time average
probability measures weakly converge to an ergodic stationary measure on the
attracting domain of an omega limit set in all classes except class 27 c).
Among them there are two classes possessing a continuum of random closed orbits
and ergodic stationary measures supported in cone surfaces, which weakly
converge to the Haar measures of periodic orbits as the noise intensity
vanishes. In the exceptional class, almost every pull-back trajectory
cyclically oscillates around the boundary of the stochastic carrying simplex
characterized by three unstable stationary solutions. The limit for the time
average probability measures is neither unique nor ergodic. These are subject
to turbulent characteristics.


title:
On the Linear Stability of Sheared and Magnetized Jets Without Current
  Sheets - Non-Relativistic Case

abstract:
  In a prior paper (Kim et al. 2015) we considered the linear stability of
magnetized jets that carry no net electric current and do not have current
sheets. In this paper, in addition to physically well-motivated magnetic field
structures, we also include the effects of jet shear. The jets we study have
finite thermal pressure in addition to having realistic magnetic field
structures and velocity shear. We find that shear has a strongly stabilizing
effect on various modes of jet instability. Increasing shear stabilizes the
fundamental pinch modes at long wavelengths and short wavelengths. Increasing
shear also stabilizes the first reflection pinch modes at short wavelengths.
Increasing shear has only a very modest stabilizing effect on the fundamental
kink modes at long wavelengths; however, increasing shear does have a strong
stabilizing effect on the fundamental kink modes at short wavelengths. The
first reflection kink modes are strongly stabilized by increasing shear at
shorter wavelengths. Overall, we find that the combined effect of magnetic
field and shear stabilizes jets more than shear alone. In addition to the
results from a formal linear stability analysis, we present a novel way of
visualizing and understanding jet stability. This gives us a deeper
understanding of the enhanced stability of sheared, magnetized jets. We also
emphasize the value of our numerical approach in understanding the linear
stability of jets with realistic structure.


title: Are we living in a quantum world? Bohr and quantum fundamentalism

abstract:
  The spectacular successes of quantum physics have made it a commonplace to
assert that we live in a quantum world. This idea seems to imply a kind of
"quantum fundamentalism" according to which everything in the universe (if not
the universe as a whole) is fundamentally of a quantum nature and ultimately
describable in quantum-mechanical terms. Bohr's conception of quantum mechanics
has traditionally been seen as opposed to such a view, not least because of his
insistence on the necessity of the concepts of classical physics in the account
of quantum phenomena. Recently, however, a consensus seems to be emerging among
careful commentators on Bohr to the effect that he, after all, did subscribe to
some version of quantum fundamentalism. Against this consensus, and by
re-examining the historical record, I will defend a variant of the traditional
reading of Bohr in which (1) the answer to what an object is (quantum or
classical) depends on the experimental context; and (2) in principle, any
physical system can be treated quantum-mechanically but not all systems can be
treated that way at the same time.


title: A note on stability of spacecrafts and underwater vehicles

abstract:
  A Hamilton-Poisson system is an approach for the motion of a spacecraft
around an asteroid or for the motion of an underwater vehicle. We construct a
coordinate chart on the symplectic leaf which contains a specific generic
equilibrium point and we establish stability conditions for this equilibrium
point.


title: Are ancient dwarf satellites the building blocks of the Galactic halo?

abstract:
  According to the current cosmological cold dark matter paradigm, the Galactic
halo could have been the result of the assemblage of smaller structures. Here
we explore the hypothesis that the classical and ultra-faint dwarf spheroidal
satellites of the Milky Way have been the building blocks of the Galactic halo
by comparing their [$\alpha$/Fe] and [Ba/Fe] versus [Fe/H] patterns with the
ones observed in Galactic halo stars. The $\alpha$ elements deviate
substantially from the observed abundances in the Galactic halo stars for
[Fe/H] values larger than -2 dex, while they overlap for lower metallicities.
On the other hand, for the [Ba/Fe] ratio the discrepancy is extended at all
[Fe/H] values, suggesting that the majority of stars in the halo are likely to
have been formed in situ. Therefore, we suggest that [Ba/Fe] ratios are a
better diagnostic than [$\alpha$/Fe] ratios. Moreover, for the first time we
consider the effects of an enriched infall of gas with the same chemical
abundances as the matter ejected and/or stripped from dwarf satellites of the
Milky Way on the chemical evolution of the Galactic halo. We find that the
resulting chemical abundances of the halo stars depend on the assumed infall
time scale, and the presence of a threshold in the gas for star formation. In
particular, in models with an infall timescale for the halo around 0.8 Gyr
coupled with a threshold in the surface gas density for the star formation (4
$\mathrm{M}_{\odot}\,\mathrm{pc}^{-2}$), and the enriched infall from dwarf
spheroidal satellites, the first halo stars formed show [Fe/H]$>$-2.4 dex. In
this case, to explain [$\alpha$/Fe] data for stars with [Fe/H]$<$-2.4 dex we
need stars formed in dSph systems.


title: Casimir-Polder interaction of neutrons with metal or dielectric surfaces

abstract:
  We predict a repulsive Casimir-Polder-type dispersion interaction between a
single neutron and a metal or dielectric surface. We consider a scenario where
a single neutron is subject to an external magnetic field. Due to its intrinsic
magnetic moment, the neutron then forms a magnetisable two-level system which
can exchange virtual photons with a nearby surface. The resulting dispersion
interaction between a purely magnetic object (neutron) and a purely electric
one (surface) is found to be repulsive, in contrast to the typical attractive
interaction between electric objects. Its magnitude is considerably smaller
than the standard atom--surface Casimir-Polder force due to the magnetic nature
of the interaction and the smallness of the electron-to-neutron mass ratio.
Nevertheless, we show that it can be comparable to the gravitational potential
of the same surface and should be taken into consideration in future neutron
interference experiments.


title: Constraints on Scalar Leptoquark from Kaon Sector

abstract:
  Recently, several anomalies in flavor physics have been observed, and it was
noticed that leptoquarks might account for the deviations from the Standard
Model. In this work, we examine the effects of new physics originating from a
scalar leptoquark model on the kaon sector. The leptoquark we consider is a
TeV-scale particle and within the reach of the LHC. We use the existing
experimental data on the several kaon processes including $K^{0}-\bar{K}^{0}$
mixing, rare decays $K^{+} \rightarrow \pi^{+} \nu \bar{\nu}$, $ K_L
\rightarrow \pi^0 \nu \bar{\nu}$, short-distance part of $K_L\rightarrow
\mu^{+}\mu^{-}$, and lepton-flavor-violating decay $K_L\rightarrow \mu^{\pm}
e^{\mp}$ to obtain useful constraints on the model.


title:
Using a conic bundle method to accelerate both phases of a quadratic
  convex reformulation

abstract:
  We present algorithm MIQCR-CB that is an advancement of method
MIQCR~(Billionnet, Elloumi and Lambert, 2012). MIQCR is a method for solving
mixed-integer quadratic programs and works in two phases: the first phase
determines an equivalent quadratic formulation with a convex objective function
by solving a semidefinite problem $(SDP)$, and, in the second phase, the
equivalent formulation is solved by a standard solver. As the reformulation
relies on the solution of a large-scale semidefinite program, it is not
tractable by existing semidefinite solvers, already for medium sized problems.
To surmount this difficulty, we present in MIQCR-CB a subgradient algorithm
within a Lagrangian duality framework for solving $(SDP)$ that substantially
speeds up the first phase. Moreover, this algorithm leads to a reformulated
problem of smaller size than the one obtained by the original MIQCR method
which results in a shorter time for solving the second phase.
  We present extensive computational results to show the efficiency of our
algorithm.


title: Where Are Most of the Globular Clusters in Today's Universe?

abstract:
  The total number of globular clusters (GCs) in a galaxy rises continuously
with the galaxy luminosity L, while the relative number of galaxies decreases
with L following the Schechter function. The product of these two very
nonlinear functions gives the relative number of GCs contained by all galaxies
at a given L. It is shown that GCs, in this universal sense, are most commonly
found in galaxies within a narrow range around $L_{\star}$. In addition, blue
(metal-poor) GCs outnumber the red (metal-richer) ones globally by 4 to 1 when
all galaxies are added, pointing to the conclusion that the earliest stages of
galaxy formation were especially favorable to forming massive, dense star
clusters.


title:
Optimizing chemoradiotherapy to target multi-site metastatic disease and
  tumor growth

abstract:
  The majority of cancer-related fatalities are due to metastatic disease. In
chemoradiotherapy, chemotherapeutic agents are administered along with
radiation to increase damage to the primary tumor and control systemic disease
such as metastasis. This work introduces a mathematical model to obtain optimal
drug and radiation protocols in a chemoradiotherapy scheduling problem with the
objective of minimizing metastatic cancer cell populations at multiple
potential sites while maintaining a minimum level of damage to the primary
tumor site. We derive closed-form expressions for an optimal chemotherapy
fractionation regimen. A dynamic programming framework is used to determine the
optimal radiotherapy fractionation regimen. Results show that chemotherapeutic
agents do not change the optimal radiation fractionation regimens, and
vice-versa. Interestingly, we observe that regardless of radio-sensitivity
parameters, hypo-fractionated schedules are optimal solutions for the
radiotherapy fractionation problem. Furthermore, it is optimal to immediately
start radiotherapy. However, for chemotherapy, we find that the structure of
the optimal schedule depends on model parameters such as chemotherapy-induced
cell-kill at primary and metastatic sites, as well as the ability of primary
tumor cells to initiate successful metastasis at different body sites. We
quantify the trade-off between the new and traditional objectives of minimizing
the metastatic population size and maximizing the tumor control probability,
respectively, for a cervical cancer case. The trade-off information indicates
the potential for significant reduction in the metastatic population with
minimal loss in primary tumor control.


title:
The evolution of Brown-York quasilocal energy due to evolution of
  Lovelock gravity in a system of M0-branes

abstract:
  Recently, it has been suggested in [JHEP 12(2015)003] that the Brown-York
mechanism can be used to measure the quasilocal energy in Lovelock gravity. We
have used this method in a system of M0-branes and show that the Brown-York
energy evolves in the process of birth and growth of Lovelock gravity. This can
help us to predict phenomenological events which are emerged as due to
dynamical structure of Lovelock gravity in our universe. In this model, first,
M0-branes join to each other and form an M3-brane and an anti-M3-branes
connected by an M2-brane. This system is named BIon. Universes and
anti-universes live on M3-branes and M2 plays the role of wormhole between
them. By passing time, M2 dissolves in M3's and nonlinear massive gravities,
like Lovelock massive gravity, emerges and grows. By closing M3-branes, BIon
evolves and wormhole between branes makes a transition to black hole. During
this stage, Brown-York energy increases and shrinks to large values at the
colliding points of branes. By approaching M3-branes towards each other, the
square energy of their system becomes negative and some tachyonic states are
produced. To remove these states, M3-branes compact, the sign of compacted
gravity changes, anti-gravity is created which leads to getting away of branes
from each other. Also, the Lovelock gravity disappears and it's energy forms a
new M2 between M3-branes. By getting away of branes from each other, Brown-York
energy decreases and shrinks to zero.


title: Analyzing Non-proportional Hazards: Use of the MRH Package

abstract:
  In this manuscript we demonstrate the analysis of right-censored survival
outcomes using the MRH package in R. The MRH package implements the
multi-resolution hazard (MRH) model, which is a Polya-tree based, Bayesian
semi-parametric method for flexible estimation of the hazard rate and covariate
effects. The package allows for covariates to be included under the
proportional and non-proportional hazards assumption, and for robust estimation
of the hazard rate in periods of sparsely observed failures via a "pruning"
tool.


title:
Dirac field as a source of the inflation in 2+1 dimensional Teleparallel
  gravity

abstract:
  In this paper, we study early-time inflation and late-time acceleration of
the universe by non-minimally coupling the Dirac field with torsion in the
spatially flat Friedman-Robertson-Walker (FRW) cosmological model background.
The results obtained by the Noether symmetry approach with and without a gauge
term are compared. Additionally, we compare these results with that of the 3+1
dimensional teleparallel gravity under Noether symmetry approach. And we see
that the study explains early-time inflation and late-time acceleration of the
universe.


title: Niels Bohr on the wave function and the classical/quantum divide

abstract:
  It is well known that Niels Bohr insisted on the necessity of classical
concepts in the account of quantum phenomena. But there is little consensus
concerning his reasons, and what he exactly meant by this. In this paper, I
re-examine Bohr's interpretation of quantum mechanics, and argue that the
necessity of the classical can be seen as part of his response to the
measurement problem. More generally, I attempt to clarify Bohr's view on the
classical/quantum divide, arguing that the relation between the two theories is
that of mutual dependence. An important element in this clarification consists
in distinguishing Bohr's idea of the wave function as symbolic from both a
purely epistemic and an ontological interpretation. Together with new evidence
concerning Bohr's conception of the wave function collapse, this sets his
interpretation apart from both standard versions of the Copenhagen
interpretation, and from some of the reconstructions of his view found in the
literature. I conclude with a few remarks on how Bohr's ideas make much sense
also when modern developments in quantum gravity and early universe cosmology
are taken into account.


title:
The Ratio of Eigenvalues of the Dirichlet Eigenvalue Problem for
  Equations with One-Dimensional p-Laplacian

abstract:
  Chao-Zhong Chen et al. $[{Proc}.$ ${Amer. Math. Soc},2013],$ proved the upper
estimate
  $\frac{\lambda _{n}}{\lambda _{m}}\leq \frac{% n^{p}}{m^{p}}$ $ (n>m\geq 1) $
for Dirichlet Shr\"{o}dinger operators with nonnegative and single-well
potentials. In this paper we discuss the case of nonpositive potentials $q(x)$
continuous on the interval $[ 0,1] $. We prove that if $q(x)\leq 0$ and
single-barrier then $\frac{\lambda _{n}}{\lambda _{m}}\geq \frac{n^{p}%
}{m^{p}}$ for $\lambda _{n}>\lambda _{m}\geq -2q^{\ast },$ where
$q^{\ast}=\inf\{q(0), q(1)\}$. Furthermore, we show that there exists
$\ell_{0}\in ( 0,1] $ such that for all $\ell\in(0,\ell_{0}],$ the associated
eigenvalues $(\lambda _{n}(\ell)) _{n\geq 1}$ (of the problem defined on
$[0,\ell]$) satisfy $ \lambda _{1}( \ell)>0$ and $\frac{\lambda _{n}(
\ell)}{\lambda _{m}( \ell) }\geq \frac{n^{p}}{m^{p}}$ $n>m\geq 1$. The value
$\ell _{0}$ satisfies the following estimate $0<\ell_{0}\leq
\sqrt[p]{\frac{-p}{3q^{*}}}$.


title:
Control of the third dimension in copper-based square-lattice
  antiferromagnets

abstract:
  Using a mixed-ligand synthetic scheme, we create a family of
quasi-two-dimensional antiferromagnets, namely, [Cu(HF$_2$)(pyz)$_2$]ClO$_4$
[pyz = pyrazine], [Cu$L_2$(pyz)$_2$](ClO$_4$)$_2$ [$L$ = pyO = pyridine-N-oxide
and 4-phpyO = 4-phenylpyridine-N-oxide. These materials are shown to possess
equivalent two-dimensional [Cu(pyz)$_2$]$^{2+}$ nearly square layers, but
exhibit interlayer spacings that vary from 6.5713~\AA ~to 16.777~\AA, as
dictated by the axial ligands. We present the structural and magnetic
properties of this family as determined via x-ray diffraction, electron-spin
resonance, pulsed- and quasistatic-field magnetometry and muon-spin rotation,
and compare them to those of the prototypical two-dimensional magnetic polymer
Cu(pyz)$_2$(ClO$_4$)$_2$. We find that, within the limits of the experimental
error, the two-dimensional, {\it intralayer} exchange coupling in our family of
materials remains largely unaffected by the axial ligand substitution, while
the observed magnetic ordering temperature decreases slowly with increasing
layer separation. Despite the structural motifs common to this family and
Cu(pyz)$_2$(ClO$_4$)$_2$, the latter has significantly stronger two-dimensional
exchange interactions and hence a higher ordering temperature. We discuss these
results, as well as the mechanisms that might drive the long-range order in
these materials, in terms of departures from the ideal $S=1/2$ two-dimensional
square-lattice Heisenberg antiferromagnet. In particular, we find that both
spin exchange anisotropy in the intralayer interaction and interlayer couplings
(exchange, dipolar, or both) are needed to account for the observed ordering
temperatures, with the intralayer anisotropy becoming more important as the
layers are pulled further apart.


title:
Low-Temperature and High-Energy-Resolution Laser Photoemission
  Spectroscopy

abstract:
  We present a review on the developments in the photoemission spectrometer
with a vacuum ultraviolet laser at Institute for Solid State Physics at the
University of Tokyo. The advantages of high energy resolution, high cooling
ability, and bulk sensitivity enable applications with a wide range of
materials. We introduce some examples of fine electronic structures detected by
laser photoemission spectroscopy and discuss the prospects of research on
low-transition-temperature superconductors exhibiting unconventional
superconductivity.


title:
Competition and duality correspondence between chiral and
  superconducting channels in (2+1)-dimensional four-fermion models with
  fermion number and chiral chemical potentials

abstract:
  In this paper the duality correspondence between fermion-antifermion and
difermion interaction channels is established in two (2+1)-dimensional
Gross-Neveu type models with a fermion number chemical potential $\mu$ and a
chiral chemical potential $\mu_5$. The role and influence of this property on
the phase structure of the models are investigated. In particular, it is shown
that the chemical potential $\mu_5$ promotes the appearance of dynamical chiral
symmetry breaking, whereas the chemical potential $\mu$ contributes to the
emergence of superconductivity.


title:
Role of remote interfacial phonon (RIP) scattering in heat transport
  across graphene/SiO2 interfaces

abstract:
  Heat transfer across interfaces of graphene and polar dielectrics (e.g. SiO2)
could be mediated by direct phonon coupling, as well as electronic coupling
with remote interfacial phonons (RIPs). To understand the relative contribution
of each component, we develop a new pump-probe technique, called
voltage-modulated thermoreflectance (VMTR), to accurately measure the change of
interfacial thermal conductance under an electrostatic field. We employed VMTR
on top gates of graphene field-effect transistors and find that the thermal
conductance of SiO2/graphene/SiO2 interfaces increases by up to {\Delta}G=0.8
MW m-2 K-1 under electrostatic fields of <0.2 V nm-1 . We propose two possible
explanations for the observed {\Delta}G. First, since the applied electrostatic
field induces charge carriers in graphene, our VMTR measurements could
originate from heat transfer between the charge carriers in graphene and RIPs
in SiO2. Second, the increase in heat conduction could be caused by better
conformity of graphene interfaces un-der electrostatic pressure exerted by the
induced charge carriers. Regardless of the origins of the observed {\Delta}G,
our VMTR measurements establish an upper limit for heat transfer from unbiased
graphene to SiO2 substrates via RIP scattering; i.e., only <2 % of the
interfacial heat transport is facilitated by RIP scattering even at a carrier
concentration of 4x10^12 cm-2.


title: About Evaluation of Complex Dynamical Systems

abstract:
  The methods are proposed for evaluation of complex dynamical systems, choice
of their optimal operating modes, determination of optimal operating system
from given class of equivalent systems, system's timeline behaviour analysis on
the basis of versatile multicriteria and multilevel analysis of behaviour of
system's elements.


title: Perturbativity and mass scales of Left-Right Higgs bosons

abstract:
  The scalar sector of the minimal Left-Right model at TeV scale is revisited
in light of the large quartic coupling needed for a heavy flavor-changing
scalar. The stability and perturbativity of the effective potential is
discussed and merged with constraints from low-energy processes. Thus the
perturbative level of the Left-Right scale is sharpened. Lower limits on the
triplet scalars are also derived: the left-handed triplet is bounded by oblique
parameters, while the doubly-charged right-handed component is limited by the
$h \to \gamma \gamma, Z \gamma$ decays. Current constraints disfavor their
detection as long as $W_R$ is within the reach of the LHC.


title: Piecewise Testable Languages and Nondeterministic Automata

abstract:
  A regular language is $k$-piecewise testable if it is a finite boolean
combination of languages of the form $\Sigma^* a_1 \Sigma^* \cdots \Sigma^* a_n
\Sigma^*$, where $a_i\in\Sigma$ and $0\le n \le k$. Given a DFA $A$ and $k\ge
0$, it is an NL-complete problem to decide whether the language $L(A)$ is
piecewise testable and, for $k\ge 4$, it is coNP-complete to decide whether the
language $L(A)$ is $k$-piecewise testable. It is known that the depth of the
minimal DFA serves as an upper bound on $k$. Namely, if $L(A)$ is piecewise
testable, then it is $k$-piecewise testable for $k$ equal to the depth of $A$.
In this paper, we show that some form of nondeterminism does not violate this
upper bound result. Specifically, we define a class of NFAs, called ptNFAs,
that recognize piecewise testable languages and show that the depth of a ptNFA
provides an (up to exponentially better) upper bound on $k$ than the minimal
DFA. We provide an application of our result, discuss the relationship between
$k$-piecewise testability and the depth of NFAs, and study the complexity of
$k$-piecewise testability for ptNFAs.