title: Visualizing automorphisms of graph algebras

abstract:
  Graph C*-algebras have been celebrated as C*-algebras that can be seen,
because many important properties may be determined by looking at the
underlying graph. This paper introduces the permutation graph for a permutative
endomorphism of a graph C*-algebra as a labeled directed multigraph that gives
a visual representation of the endomorphism and facilitates computations.
Combinatorial criteria have previously been developed for deciding when such an
endomorphism is an automorphism, but here the question is reformulated in terms
of the permutation graph and new proofs are given. Furthermore, it is shown how
to use per- mutation graphs to efficiently generate exhaustive collections of
permutative automorphisms. Permutation graphs provide a natural link to the
textile systems representing induced endo- morphisms on the edge shift of the
given graph, and this allows the powerful tools of the theory of textile
systems developed by Nasu to be applied to the study of permutative
endomorphisms.


title: Strict Deformation Quantisation of the G-connections via Lie Groupoid

abstract:
  Motivated by the compactification process of the space of connections in loop
quantum gravity literature. A description of the space of G-connections using
the tangent groupoid is given. As the tangent groupoid parameter is away from
zero, the G-connections are (strictly) deformation quantised to noncommuting
elements using C*-algebraic formalism. The approach provides a mean to
obtaining a semi-classical limit in loop quantum gravity.


title: Modeling Emotion Influence from Images in Social Networks

abstract:
  Images become an important and prevalent way to express users' activities,
opinions and emotions. In a social network, individual emotions may be
influenced by others, in particular by close friends. We focus on understanding
how users embed emotions into the images they uploaded to the social websites
and how social influence plays a role in changing users' emotions. We first
verify the existence of emotion influence in the image networks, and then
propose a probabilistic factor graph based emotion influence model to answer
the questions of "who influences whom". Employing a real network from Flickr as
experimental data, we study the effectiveness of factors in the proposed model
with in-depth data analysis. Our experiments also show that our model, by
incorporating the emotion influence, can significantly improve the accuracy
(+5%) for predicting emotions from images. Finally, a case study is used as the
anecdotal evidence to further demonstrate the effectiveness of the proposed
model.


abstract:
  This work extends Perron's method for the porous medium equation in the slow
diffusion case. The main result shows that nonnegative continuous boundary
functions are resolutive in a general cylindrical domain.


title:
Critical doping for the onset of a two-band superconducting ground state
  in SrTiO$_{3-\delta}$

abstract:
  In doped SrTiO$_{3}$ superconductivity persists down to an exceptionally low
concentration of mobile electrons. This restricts the relevant energy window
and possible pairing scenarios. We present a study of quantum oscillations and
superconducting transition temperature, $T_{c}$ as the carrier density is tuned
from $10^{17}$ to $10^{20}$ $cm^{-3}$ and identify two critical doping levels
corresponding to the filling thresholds of the upper bands. At the first
critical doping, which separates the single-band and the two-band
superconducting regimes in oxygen-deficient samples, the steady increase of
T$_{c}$ with carrier concentration suddenly stops. Near this doping level, the
energy dispersion in the lowest band displays a downward deviation from
parabolic behavior. The results impose new constraints for microscopic pairing
scenarios.


title:
Analysis of the stability of stationary boundary friction modes in the
  framework of a synergetic model

abstract:
  A synergetic model describing the state of an ultrathin lubricant layer
squeezed between two atomically smooth solid surfaces operating in the boundary
friction mode has been developed further. To explain the presence of different
operation modes of the system for various sets of its main parameters, the
mathematical analysis of the synergetic model is carried out. The type of
functioning a tribological system is described in accordance with the stability
character of singular points, and the diagrams distinguishing various operation
modes are obtained. Phase portraits corresponding to different stability types
are plotted for all diagram areas. A stick-slip mode of motion that is often
observed experimentally is described.

categories: cond-mat.mes-hall cond-mat.stat-mech nlin.CD physics.flu-dyn


title: Experimental Study on Bouncing Barriers in Protoplanetary Disks

abstract:
  For dust aggregates in protoplanetary discs a transition between sticking and
bouncing in individual collisions at mm to cm size has been observed in the
past. This lead to the notion of a bouncing barrier for which growth gets
stalled. Here, we present long term laboratory experiments on the outcome of
repeated aggregate collisions at the bouncing barrier. About 100 SiO$_2$ dust
aggregates of 1 mm in size were observed interacting with each other.
Collisions occured within a velocity range from below mm/s up to cm/s.
Aggregates continuously interacted with each other over a period of 900 s.
During this time more than $10^5$ collisions occured. Nearly 2000 collisions
were analyzed in detail. No temporal stable net growth of larger aggregates was
observed even though sticking collision occur. Larger ensembles of aggregates
sticking together are formed but were disassembled again during the further
collisional evolution. The concept of a bouncing barrier supports the formation
of planetesimals by seeded collisional growth as well as by gravitational
instability favouring a significant total mass being limited to certain size
ranges. Within our parameter set the experiments confirm that bouncing barriers
are one possible and likely evolutionary limit of a self consistent particle
growth.


title:
The photometric system of the One-meter Telescope at Weihai Observatory
  of Shandong University

abstract:
  The one-meter telescope at Weihai Observatory of Shandong University is an
f/8 Cassegrain telescope. Three sets of filters, including Johnson--Cousins
UBVRI, Sloan Digital Sky Survey u$'$g$'$r$'$i$'$z$'$ and Str\"{o}mgren uvby,
are installed in a dual layer filterwheel. The photometric system and the CCD
camera are introduced in this paper, followed by detailed analysis of their
performances, and determination of the relevant parameters, including gain,
readout noise, dark current and linearity of the CCD camera. In addition, the
characteristics of the site astro-climate condition, including typical seeing,
clear nights statistics, and average sky brightness were studied systematically
based on data gathered from Sep. 2007 to Aug. 2013, and were reported in this
work. Photometric calibrations were done using 8 nights Landolt standard star
observations, which yielded transformation coefficients, photometry precision
and system throughput. The limiting magnitudes were simulated using the derived
calibration parameters and classic observation conditions at WHO.


title:
The Secret Life of a Process Description: A Look into the Evolution of a
  Large Process Model

abstract:
  Software process models must change continuously in order to remain
consistent over time with the reality they represent, as well as relevant to
the task they are intended for. Performing these changes in a sound and disci-
plined fashion requires software process model evolution to be understood and
controlled. The current situation can be characterized by a lack of
understanding of software process model evolution and, in consequence, by a
lack of systematic support for evolving software process models in
organizations. This paper presents an analysis of the evolution of a large
software process standard, namely, the process standard for the German Federal
Government (V-Modell(R) XT). The analysis was performed with the Evolyzer tool
suite, and is based on the complete history of over 600 versions that have been
created during the development and maintenance of the standard. The analysis
reveals similarities and differences between process evolution and empirical
findings in the area of software system evolution. These findings provide hints
on how to better manage process model evolution in the future.


title: Hybridization of Graphene and a Ag Monolayer Supported on Re(0001)

abstract:
  We have investigated the electronic structure of graphene supported on
Re(0001) before and after the intercalation of one monolayer of Ag by means of
angle-resolved photoemission spectroscopy measurements and density functional
theory calculations. The intercalation of Ag reduces the graphene-Re
interaction and modifies the electronic band structure of graphene. Although
the linear dispersion of the {\pi} state of graphene in proximity of the Fermi
level highlights a rather weak graphene-noble metal layer interaction, we still
observe a significant hybridization between the Ag bands and the {\pi} state in
lower energy regions. These results demonstrate that covering a surface with a
noble metal layer does decouple the electronic states, but still leads to a
noticeable change in the electronic structure of graphene.


title:
Absolutely continuous energy bands and extended electronic states in an
  aperiodic comb-shaped nanostructure

abstract:
  The nature of electronic eigenstates and quantum transport in a comb-shaped
Fibonacci nanostructure model is investigated within a tight-binding framework.
Periodic linear chains are side-attached to a Fibonacci chain, giving it the
shape of an aperiodic comb. The effect of the side-attachments on the usual
Cantor set energy spectrum of a Fibonacci chain is analyzed using the Greens
function technique. A special correlation between the coupling of the
side-attached chain with the Fibonacci chain and the inter-atomic coupling of
the Fibonacci chain results in a dramatic triggering of the fragmented Cantor
set energy spectrum into multiple sets of continuous sub-bands of extended
eigenstates. The result is valid even for a disordered comb and turns out to be
a rare exception of the conventional Anderson localization problem. The
electronic transport thus can be made selectively ballistic within desired
energy regimes. The number and the width of such continuous sub-bands can be
easily controlled by tuning the number of atomic sites in the side-coupled
periodic linear chains. This gives us a scope of proposing such aperiodic
nanostructures as potential candidates for prospective energy selective
nanoscale filtering devices.


title:
A Carbon Corrosion Model to Evaluate the Effect of Steady State and
  Transient Operation of a Polymer Electrolyte Membrane Fuel Cell

abstract:
  A carbon corrosion model is developed based on the formation of surface
oxides on carbon and platinum of the polymer electrolyte membrane fuel cell
electrode. The model predicts the rate of carbon corrosion under potential hold
and potential cycling conditions. The model includes the interaction of carbon
surface oxides with transient species like OH radicals to explain observed
carbon corrosion trends under normal PEM fuel cell operating conditions. The
model prediction agrees qualitatively with the experimental data supporting the
hypothesis that the interplay of surface oxide formation on carbon and platinum
is the primary driver of carbon corrosion.


title: Modeling of durability of polyelectrolyte membrane of O2/H2 fuel cell

abstract:
  In this paper, we discuss critical aspects of the mechanisms and features of
polymer proton exchange membrane (PEM) degradation in low-temperature H2/O2
fuel cell. In this paper, we focused on chemical mechanism of OH radical
generation and their distribution in operational fuel cell. According to the
current concept, free radicals are generated from hydrogen and oxygen crossover
gases at the surface of Pt particles that precipitated in the membrane. We
explicitly calculate Pt precipitation rate and electrochemical potential
distribution in the membrane that controls it. Based on radical generation rate
and Pt distribution we calculate degradation rate of the membrane taking
advantage of simple kinetics equations.


title: The model of stress distribution in polymer electrolyte membrane

abstract:
  An analytical model of mechanical stress in a polymer electrolyte membrane
(PEM) of a hydrogen/air fuel cell with porous Water Transfer Plates (WTP) is
developed in this work. The model considers a mechanical stress in the membrane
is a result of the cell load cycling under constant oxygen utilization. The
load cycling causes the cycling of the inlet gas flow rate, which results in
the membrane hydration/dehydration close to the gas inlet.
Hydration/dehydration of the membrane leads to membrane swelling/shrinking,
which causes mechanical stress in the constrained membrane. Mechanical stress
results in through-plane crack formation. Thereby, the mechanical stress in the
membrane causes mechanical failure of the membrane, limiting fuel cell
lifetime. The model predicts the stress in the membrane as a function of the
cell geometry, membrane material properties and operation conditions. The model
was applied for stress calculation in GORE-SELECT.


title:
A characterization of the Gaussian Lipschitz space and sharp estimates
  for the Ornstein-Uhlenbeck Poisson kernel

abstract:
  The Gaussian Lipschitz space was defined by Gatto and Urbina, by means of the
Ornstein-Uhlenbeck Poisson kernel. We give a characterization of this space in
terms of a combination of ordinary Lipschitz continuity conditions. The main
tools used in the proof are sharp estimates of the Ornstein-Uhlenbeck Poisson
kernel and some of its derivatives.


title:
Incidence, recovery and prevalence of infectious diseases:
  non-parametric disease model and application to influenza in Germany

abstract:
  In this work we describe a non-parametric disease model that links the
temporal change of the prevalence of an infectious disease to the incidence and
the recovery rates. The model is only based on the common epidemiological
measures incidence and recovery rate. As an application, the model is used to
calculate the prevalence of influenza in Germany for a hypothetical birth
cohort during 2001 and 2013.


title: Attosecond Photoscopy of Plasmonic Excitations

abstract:
  We propose an experimental arrangement to image, with attosecond resolution,
transient surface plasmonic excitations. The required modifications to
state-of-the-art setups used for attosecond streaking experiments from solid
surfaces only involve available technology. Buildup and life times of surface
plasmon polaritons can be extracted and local modulations of the exciting
optical pulse can be diagnosed {\it in situ}.


title:
Efficient shortcuts to adiabatic passage for the fast populations
  transfer in multiparticle systems

abstract:
  Achieving fast populations transfer (FPT) in multiparticle systems based on
the cavity quantum electronic dynamics (CQED) is an outstanding challenge. In
this paper, motivated by the quantum Zeno dynamics (QZD), a shortcut for
performing the FPT of ground states in multiparticle systems with the invariant
based inverse engineering is proposed. Numerical simulation demonstrates that a
perfect populations transfer of ground states in multiparticle systems can be
rapidly achieved in one step, and the FPT is robust to both the cavity decay
and atomic spontaneous emission. Additionally, this scheme is not only
implemented without requiring extra complex conditions, but also insensitive to
variations of the parameters.


title:
From static to rotating to conformal static solutions: Rotating
  imperfect fluid wormholes with(out) electric or magnetic field

abstract:
  We derive a shortcut stationary metric formula for generating imperfect fluid
rotating solutions, in Boyer-Lindquist coordinates, from spherically symmetric
static ones. We explore the properties of the curvature scalar and
stress-energy tensor for all types of rotating regular solutions we can
generate without restricting ourselves to specific examples of regular
solutions (regular black holes or wormholes). We show through examples how it
is generally possible to generate an imperfect fluid regular rotating solution
via radial coordinate transformations. We derive rotating wormholes that are
modeled as imperfect fluids and discuss their physical properties that are
independent on the way the stress-energy tensor is interpreted. A solution
modeling an imperfect fluid rotating loop black hole is briefly discussed. We
then specialize to the recently discussed stable exotic dust Ellis wormhole
emerged in a source-free radial electric or magnetic field, generate its,
conjecturally stable, rotating counterpart which turns out to be an exotic
imperfect fluid wormhole and determine the stress-energy tensor of both the
imperfect fluid and the electric or magnetic field.


title:
Lattice QCD study of partial restoration of chiral symmetry in the
  flux-tube

abstract:
  Using the overlap-Dirac eigenmodes, we study the spatial distribution of the
chiral condensate around static color sources in lattice QCD. Between the color
sources, there appears a color-flux tube, which leads a linear confining
potential. By measuring a local value of the chiral condensate, we show that
the magnitude of the condensate is reduced inside the flux-tube for both
quark-antiquark and three-quark systems. These results suggest that chiral
symmetry is partially restored in the flux-tube. The reduction of the
condensate is estimated to be about 20 $\sim$ 30% at the center of the flux.


title:
Variable-step finite difference schemes for the solution of
  Sturm-Liouville problems

abstract:
  We discuss the solution of regular and singular Sturm-Liouville problems by
means of High Order Finite Difference Schemes. We describe a code to define a
discrete problem and its numerical solution by means of linear algebra
techniques. Different test problems are proposed to emphasize the behaviour of
the proposed algorithm.


title: Molecular dynamics simulation of chains mobility in polyethylene crystal

abstract:
  The mobility of polymer chains in perfect polyethylene (PE) crystal was
calculated as a function of temperature and chain length through Molecular
dynamics (MD) in united atom approximation. The results demonstrate that the
chain mobility drastically increases in the vicinity of the phase transition
from the orthorhombic to quasi-hexagonal phase. In the quasi-hexagonal phase,
the chain mobility is almost independent on temperature and inversely
proportional to the chain length.


title: Values of twisted Artin $L$-functions

abstract:
  This note gives a simple proof that certain values of Artin's $L$-function,
for a representation $\rho$ with character $\chi_\rho$, are stable under
twisting by an even Dirichlet character $\chi$, up to an element generated over
$\mathbb Q$ by the values of $\chi$ and $\chi_\rho$, and a product with a power
of the Gauss sum $\tau(\chi)$ equal to the dimension of $\rho$. This extends a
result due to J. Coates and S. Lichtenbaum.


title:
Cartan equivalences for 5-dimensional CR-manifolds in C^4 belonging to
  General Class III_1

abstract:
  We reduce to various absolute parallelisms, namely to certain {e}-structures
on manifolds of dimensions 7, 6, 5, the biholomorphic equivalence problem or
the intrinsic CR equivalence problem for generic submanifolds M^5 in C^4 of CR
dimension 1 and of codimension 3 that are maximally minimal and are
geometry-preserving deformations of one natural cubic model of Beloshapka,
somewhere else called the General Class III-1 of 5-dimensional CR manifolds.
Some inspiration links exist with the treatment of the General Class II
previously done in 2007 by Beloshapka, Ezhov, Schmalz, and also with the
classification of nilpotent Lie algebras due to Goze, Khakimdjanov, Remm.


title: What can transmission do for a fully renewable Europe?

abstract:
  Our research is centred around the question how to best integrate the
variable renewable energy sources (VRES), wind power and solar photovoltaics,
into the European electricity grid. The future electricity supply will be based
to a large extend on these fluctuating resources. We have conducted a study,
extrapolating national historical and targeted wind and solar power
penetrations in Europe up to 100% VRES (R.A. Rodriguez et al, Renewable Energy
63, p. 467, Mar 2014 and S. Becker et al, Energy 64, p. 404, Jan 2014). A high
share of VRES means large fluctuations in the generation, causing
overproduction and deficits. One way to reduce such mismatches is power
transmission spatially smoothing out the fluctuations. This has the potential
to reduce the remaining shortages by sharing the surplus production of others.
We find that shortages can at maximum be reduced by 40% in the hypothetical
case of unlimited transmission capacities across all of Europe. A more
realistic extension of the transmission grid, roughly quadrupling today's
installation, turns out to be sufficient to harvest 90% of this potential
benefit. Finally, the import and export of single countries is investigated. We
conclude that a country's load size as well as its position in the network are
the determining factors for its import/export opportunities.


title:
On the role of the H2 ortho:para ratio in gravitational collapse during
  star formation

abstract:
  Hydrogen molecules (H2) come in two forms in the interstellar medium, ortho-
and para-hydrogen, corresponding to the two different spin configurations of
the two hydrogen atoms. The relative abundances of the two flavours in the
interstellar medium are still very uncertain, and this abundance ratio has a
significant impact on the thermal properties of the gas. In the context of star
formation, theoretical studies have recently adopted two different strategies
when considering the ortho:para ratio (OPR) of H2 molecules; the first
considers the OPR to be frozen at 3:1 while the second assumes that the species
are in thermal equilibrium. As the OPR potentially affects the protostellar
cores which form as a result of the gravitational collapse of a dense molecular
cloud, the aim of this paper is to quantify precisely what role the choice of
OPR plays in the properties and evolution of the cores. We used two different
ideal gas equations of state for a hydrogen and helium mix in a radiation
hydrodynamics code to simulate the collapse of a dense cloud and the formation
of the first and second Larson cores; the first equation of state uses a fixed
OPR of 3:1 while the second assumes thermal equilibrium. Simulations using an
equilibrium ratio collapse faster at early times and show noticeable
oscillations around hydrostatic equilibrium, to the point where the core
expands for a short time right after its formation before resuming its
contraction. In the case of a fixed 3:1 OPR, the core's evolution is a lot
smoother. The OPR was however found to have little impact on the size, mass and
radius of the two Larson cores. We conclude that if one is solely interested in
the final properties of the cores when they are formed, it does not matter
which OPR is used. On the other hand, if one's focus lies primarily in the
evolution of the first core, the choice of OPR becomes important.


title: From toroidal to rod-like condensates of semiflexible polymers

abstract:
  The competition between toroidal and rod-like conformations as possible
ground states for DNA condensation is studied as a function of the stiffness,
the length of the DNA and the form of the long-range interactions between
neighboring molecules, using analytical theory supported by Monte Carlo
simulations. Both conformations considered are characterized by a local nematic
order with hexagonal packing symmetry of neighboring DNA molecules, but differ
in global configuration of the chain and the distribution of its curvature as
it wraps around to form a condensate. The long-range interactions driving the
DNA condensation are assumed to be of the form pertaining to the attractive
depletion potential as well as the attractive counterion induced soft
potential. In the stiffness-length plane we find a transition between rod-like
to toroid condensate for increasing stiffness at a fixed chain length $L$.
Strikingly, the transition line is found to have a $L^{1/3}$ dependence
irrespective of the details of the long-range interactions between neighboring
molecules. When realistic DNA parameters are used, our description reproduces
rather well some of the experimental features observed in DNA condensates.


title: Weak solutions to the stationary incompressible Euler equations

abstract:
  We consider weak stationary solutions to the incompressible Euler equations
and show that the analogue of the h-principle obtained in [5, 7] for
time-dependent weak solutions continues to hold. The key difference arises in
dimension d = 2, where it turns out that the relaxation is strictly smaller
than what one obtains in the time-dependent case.


title: Stochastic patterns in a 1D Rock-Paper-Scissor model with mutation

abstract:
  In the framework of a 1D cyclic competition model, the Rock-Paper-Scissor
model, where bacteria are allowed to mutate and move in space, we study the
formation of stochastic patterns, where all the bacteria species do coexist. We
modelled the problem using an individual-based setting and using the system
size van Kampen expansion to deal with the Master Equation, we have been able
to characterise the spatio-temporal patterns using the power spectrum of the
fluctuations. We proved that such patterns are robust against the intrinsic
noise and they can be found for parameters values beyond the ones fixed by the
deterministic approach. We complement such analytical results with numerical
simulations based on the Gillespie's algorithm.


title:
Theoretical description and measurement of the pion-photon transition
  form factor

abstract:
  Detailed predictions for the scaled pion-photon transition form factor are
given, derived with the method of light-cone sum rules and using pion
distribution amplitudes with two and three Gegenbauer coefficients obtained
from QCD sum rules with nonlocal condensates. These predictions agree well with
all experimental data that are compatible with QCD scaling (and collinear
factorization), but disagree with the high-$Q^2$ data of the BaBar
Collaboration that grow with the momentum. A good agreement of our predictions
with results obtained from AdS/QCD models and Dyson-Schwinger computations is
found.


title:
Theoretical and Experimental Studies on a Cylinder Containing Granules
  Rolling Down an Inclined Plane

abstract:
  The dynamics of a hollow cylinder containing granules and rolling down an
inclined plane was investigated. A theoretical approach for investigating the
behaviour of such a cylinder was proposed. The critical angle of the plane that
allows the system to roll downward is presented. A simple experiment using six
types of granules consistently confirmed the theoretical predictions. We showed
that the critical angle is independent of the size distribution of the
granules. We observed that the sliding angle of granules inside the cylinder is
constant and, surprisingly, similar to the avalanche angle of the granules. Our
theoretical prediction can be used to determine the critical angle without
considering the shape, surface roughness and size distribution of the granules.
Additionally, we derived the oscillation frequency of the system when it is
slightly deviated from equilibrium, showing the frequency initially increases
and then decreases with increasing granular volume. The oscillation is absent
when the cylinder is empty or fully filled with granules. Furthermore, the
dissipation of energy as a function of the fractional volume and fractional
mass of the cylinder system were determined. This work might help students
understand rolling motions other than the standard rolling motion commonly
taught in the classroom.


title:
High Luminance Organic Light-Emitting Diodes with Efficient Multi-Walled
  Carbon Nanotube Hole Injectors

abstract:
  We report high luminance organic light-emitting diodes by use of acid
functionalized multi-walled carbon nanotube (o-MWCNTs) as efficient hole
injector electrodes with a simple and solution processable device structure. At
only 10 V, the luminance can reach nearly 50,000 cd/m2 with an external quantum
efficiency over 2% and a current efficiency greater than 21 cd/A. The
investigation of hole-only devices shows that the mechanism for hole injection
is changed from injection limited to bulk limited because of the higher
effective work function of the anode modified by the o-MWCNTs. We expect the
enhancement of the local electric field brought about by both the dielectric
inhomogeneities within the o-MWCNT containing anode and the high aspect ratio
carbon nanotubes, improves hole injection from the anode to organic active
layer at much lower applied voltage.


title: Angular correlations measured in pp collisions by ALICE at the LHC

abstract:
  We report on studies of untriggered two-particle angular correlations of
identified particles (pions, kaons and protons) measured in proton-proton
collisions at center-of-mass energy sqrt{s}=7 TeV recorded by ALICE at the LHC.
These type of studies are sensitive to a wide range of correlations which arise
from different physics mechanisms, each of them having a unique structure in
DeltaEta-DeltaPhi space. The correlations of particles with different quark
content and flavor are sensitive to various conservation laws. The study of
these correlations is the main goal of this analysis. The results confirm that
these laws strongly influence the shape of the correlation functions for
different particle types and must be taken into account while analysing the
data. Moreover, we verify their implementation using two Monte Carlo event
generators and we found that the analyzed models do not reproduce the measured
correlations for protons.


title:
The Research Object Suite of Ontologies: Sharing and Exchanging Research
  Data and Methods on the Open Web

abstract:
  Research in life sciences is increasingly being conducted in a digital and
online environment. In particular, life scientists have been pioneers in
embracing new computational tools to conduct their investigations. To support
the sharing of digital objects produced during such research investigations, we
have witnessed in the last few years the emergence of specialized repositories,
e.g., DataVerse and FigShare. Such repositories provide users with the means to
share and publish datasets that were used or generated in research
investigations. While these repositories have proven their usefulness,
interpreting and reusing evidence for most research results is a challenging
task. Additional contextual descriptions are needed to understand how those
results were generated and/or the circumstances under which they were
concluded. Because of this, scientists are calling for models that go beyond
the publication of datasets to systematically capture the life cycle of
scientific investigations and provide a single entry point to access the
information about the hypothesis investigated, the datasets used, the
experiments carried out, the results of the experiments, the people involved in
the research, etc. In this paper we present the Research Object (RO) suite of
ontologies, which provide a structured container to encapsulate research data
and methods along with essential metadata descriptions. Research Objects are
portable units that enable the sharing, preservation, interpretation and reuse
of research investigation results. The ontologies we present have been designed
in the light of requirements that we gathered from life scientists. They have
been built upon existing popular vocabularies to facilitate interoperability.
Furthermore, we have developed tools to support the creation and sharing of
Research Objects, thereby promoting and facilitating their adoption.


title:
Axisymmetric equilibrium models for magnetized neutron stars in General
  Relativity under the Conformally Flat Condition

abstract:
  Extremely magnetized neutron stars with magnetic fields as strong as $\sim
10^{15-16}$ G, or magnetars, have received considerable attention in the last
decade due to their identification as a plausible source for Soft Gamma
Repeaters and Anomalous X-ray Pulsars. Moreover, this class of compact objects
has been proposed as a possible engine capable of powering both Long and Short
Gamma-Ray Bursts, if the rotation period in their formation stage is short
enough (~1 ms). Such strong fields are expected to induce substantial
deformations of the star and thus to produce the emission of gravitational
waves. Here we investigate, by means of numerical modeling, axisymmetric static
equilibria of polytropic and strongly magnetized stars in full general
relativity, within the ideal magneto-hydrodynamic regime. The eXtended
Conformally Flat Condition (XCFC) for the metric is assumed, allowing us to
employ the techniques introduced for the X-ECHO code [Bucciantini & Del Zanna,
2011, Astron. Astrophys. 528, A101], proven to be accurate, efficient, and
stable. The updated XNS code for magnetized neutron star equilibria is made
publicly available for the community (see
www.arcetri.astro.it/science/ahead/XNS). Several sequences of models are here
retrieved, from the purely toroidal (resolving a controversy in the literature)
or poloidal cases, to the so-called twisted torus mixed configurations,
expected to be dynamically stable, which are solved for the first time in the
non-perturbative regime.


title: The behavior of Stanley depth under polarization

abstract:
  Let $K$ be a field, $R=K[X_1, ..., X_n]$ be the polynomial ring and $J
\subsetneq I$ two monomial ideals in $R$. In this paper we show that
$\mathrm{sdepth}\ {I/J} - \mathrm{depth}\ {I/J} = \mathrm{sdepth}\
{I^p/J^p}-\mathrm{depth}\ {I^p/J^p}$, where $\mathrm{sdepth}\ I/J$ denotes the
Stanley depth and $I^p$ denotes the polarization. This solves a conjecture by
Herzog and reduces the famous Stanley conjecture (for modules of the form
$I/J$) to the squarefree case. As a consequence, the Stanley conjecture for
algebras of the form $R/I$ and the well-known combinatorial conjecture that
every Cohen-Macaulay simplicial complex is partitionable are equivalent.


title: On the absolute value of the air-fluorescence yield

abstract:
  The absolute value of the air-fluorescence yield is a key parameter for the
energy reconstruction of extensive air showers registered by fluorescence
telescopes. In previous publications, we reported a detailed Monte Carlo
simulation of the air-fluorescence generation that allowed the theoretical
evaluation of this parameter. This simulation has been upgraded in the present
work. As a result, we determined an updated absolute value of the fluorescence
yield of 7.9+-2.0 ph/MeV for the band at 337 nm in dry air at 800 hPa and 293
K, in agreement with experimental values. We have also performed a critical
analysis of available absolute measurements of the fluorescence yield with the
assistance of our simulation. Corrections have been applied to some
measurements to account for a bias in the evaluation of the energy deposition.
Possible effects of other experimental aspects have also been discussed. From
this analysis, we determined an average fluorescence yield of 7.04+-0.24 ph/MeV
at the above conditions.


title:
Preasymptotic error analysis of higher order FEM and CIP-FEM for
  Helmholtz equation with high wave number

abstract:
  A preasymptotic error analysis of the finite element method (FEM) and some
continuous interior penalty finite element method (CIP-FEM) for Helmholtz
equation in two and three dimensions is proposed. $H^1$- and $L^2$- error
estimates with explicit dependence on the wave number $k$ are derived. In
particular, it is shown that if $k^{2p+1}h^{2p}$ is sufficiently small, then
the pollution errors of both methods in $H^1$-norm are bounded by
$O(k^{2p+1}h^{2p})$, which coincides with the phase error of the FEM obtained
by existent dispersion analyses on Cartesian grids, where $h$ is the mesh size,
$p$ is the order of the approximation space and is fixed. The CIP-FEM extends
the classical one by adding more penalty terms on jumps of higher (up to $p$-th
order) normal derivatives in order to reduce efficiently the pollution errors
of higher order methods. Numerical tests are provided to verify the theoretical
findings and to illustrate great capability of the CIP-FEM in reducing the
pollution effect.


title:
Super-Resolution Compressed Sensing: An Iterative Reweighted Algorithm
  for Joint Parameter Learning and Sparse Signal Recovery

abstract:
  In many practical applications such as direction-of-arrival (DOA) estimation
and line spectral estimation, the sparsifying dictionary is usually
characterized by a set of unknown parameters in a continuous domain. To apply
the conventional compressed sensing to such applications, the continuous
parameter space has to be discretized to a finite set of grid points.
Discretization, however, incurs errors and leads to deteriorated recovery
performance. To address this issue, we propose an iterative reweighted method
which jointly estimates the unknown parameters and the sparse signals.
Specifically, the proposed algorithm is developed by iteratively decreasing a
surrogate function majorizing a given objective function, which results in a
gradual and interweaved iterative process to refine the unknown parameters and
the sparse signal. Numerical results show that the algorithm provides superior
performance in resolving closely-spaced frequency components.


title:
Robust Bayesian compressed sensing over finite fields: asymptotic
  performance analysis

abstract:
  This paper addresses the topic of robust Bayesian compressed sensing over
finite fields. For stationary and ergodic sources, it provides asymptotic (with
the size of the vector to estimate) necessary and sufficient conditions on the
number of required measurements to achieve vanishing reconstruction error, in
presence of sensing and communication noise. In all considered cases, the
necessary and sufficient conditions asymptotically coincide. Conditions on the
sparsity of the sensing matrix are established in presence of communication
noise. Several previously published results are generalized and extended.


title: Local Segmental Dynamics and Stresses in Polystyrene - C$_{60}$ Mixtures

abstract:
  The polymer dynamics of homogeneous C$_{60}$-polystyrene mixtures in the
molten state are studied via molecular simulations using two interconnected
levels of representation for polystyrene nanocomposites: (a) A coarse-grained
representation, in which each polystyrene repeat unit is mapped into a single
"superatom" and each fullerene is viewed as a spherical shell. Equilibration of
coarse-grained polymer-nanoparticle systems at all length scales is achieved
via connectivity-altering Monte Carlo simulations. (b) An atomistic
representation, where both nanoparticles and polymer chains are represented in
terms of united-atom forcefields. Initial configurations for atomistic
Molecular Dynamics (MD) simulations are obtained by reverse mapping
well-equilibrated coarse-grained configurations. By analyzing MD trajectories
under constant energy, the segmental dynamics of polystyrene (for neat and
filled systems) is characterized in terms of bond orientation time
autocorrelation functions. Nanocomposite systems are found to exhibit slightly
slower segmental dynamics than the unfilled ones, in good agreement with
available experimental data. Moreover, by employing Voronoi tessellation of the
simulation box, the mean-squared displacement of backbone carbon atoms is
quantified in the vicinity of each fullerene molecule. Fullerenes are found to
suppress the average motion of polymeric chains, in agreement with neutron
scattering data, while slightly increasing the dynamic and stress heterogeneity
of the melt. Atomic-level and local (per Voronoi cell) stress distributions are
reported for the pure and the filled systems.


title:
Adiabatic Approximation, Semiclassical Scattering, and Unidirectional
  Invisibility

abstract:
  The transfer matrix of a possibly complex and energy-dependent scattering
potential can be identified with the $S$-matrix of a two-level time-dependent
non-Hermitian Hamiltonian H(t). We show that the application of the adiabatic
approximation to H(t) corresponds to the semiclassical description of the
original scattering problem. In particular, the geometric part of the phase of
the evolving eigenvectors of H(t) gives the pre-exponential factor of the WKB
wave functions. We use these observations to give an explicit semiclassical
expression for the transfer matrix. This allows for a detailed study of the
semiclassical unidirectional reflectionlessness and invisibility. We examine
concrete realizations of the latter in the realm of optics.


title:
Sharp low frequency resolvent estimates on asymptotically conical
  manifolds

abstract:
  On a class of asymptotically conical manifolds, we prove two types of low
frequency estimates for the resolvent of the Laplace-Beltrami operator. The
first result is a uniform $ L^2 \rightarrow L^2 $ bound for $ \langle r
\rangle^{-1} (- \Delta_G - z)^{-1} \langle r \rangle^{-1} $ when $ \mbox{Re}(z)
$ is small, with the optimal weight $ \langle r \rangle^{-1} $. The second one
is about powers of the resolvent. For any integer $N$, we prove uniform $ L^2
\rightarrow L^2 $ bounds for $ \langle \epsilon r \rangle^{-N} (-\epsilon^{-2}
\Delta_G - Z)^{-N} \langle \epsilon r \rangle^{-N} $ when $ \mbox{Re}(Z) $
belongs to a compact subset of $ (0,+\infty) $ and $ 0 < \epsilon \ll 1 $.
These results are obtained by proving similar estimates on a pure cone with a
long range perturbation of the metric at infinity.


title: An efficient method for solving a correlated multi-item inventory system

abstract:
  We propose an efficient method of finding an optimal solution for a
multi-item continuous review inventory model in which a bivariate Gaussian
probability distribution represents a correlation between the demands of
different items. By utilizing appropriate normalizations of the demands, we
show that the normalized demands are uncorrelated. Furthermore, the set of
equations coupled with different items can be decoupled in such a way that the
order quantity and reorder point for each item can be evaluated independently
from those of the other. As a result, in contrast to conventional methods, the
solution procedure for the proposed method can be much simpler and more
accurate without any approximation. To demonstrate the advantage of the
proposed method, we present a solution scheme for a multi-item continuous
review inventory model in which the demand of optional components depend on
that of a "vanilla box", representing the customer's stochastic demand, under
stochastic payment and budget constraints. We also perform a sensitivity
analysis to investigate the dependence of order quantities and reorder points
on the correlation coefficient.


title: Quantum Imaging with Undetected Photons

abstract:
  Indistinguishable quantum states interfere, but the mere possibility of
obtaining information that could distinguish between overlapping states
inhibits quantum interference. Quantum interference imaging can outperform
classical imaging or even have entirely new features. Here, we introduce and
experimentally demonstrate a quantum imaging concept that relies on the
indistinguishability of the possible sources of a photon that remains
undetected. Our experiment uses pair creation in two separate down-conversion
crystals. While the photons passing through the object are never detected, we
obtain images exclusively with the sister photons that do not interact with the
object. Therefore the object to be imaged can be either opaque or invisible to
the detected photons. Moreover, our technique allows the probe wavelength to be
chosen in a range for which suitable sources and/or detectors are unavailable.
Our experiment is a prototype in quantum information where knowledge can be
extracted by and about a photon that is never detected.


title:
Position-dependent effect of non-magnetic impurities on superconducting
  properties of nanowires

abstract:
  Anderson's theorem states that non-magnetic impurities do not change the bulk
properties of conventional superconductors. However, as the dimensionality is
reduced, the effect of impurities becomes more significant. Here we investigate
superconducting nanowires with diameter less than the superconducting coherence
length by using a microscopic description based on the Bogoliubov-de Gennes
method. We find that: 1) impurities strongly affect the superconducting
properties, 2) the effect is impurity position-dependent, and 3) it exhibits
opposite behavior for resonant and off-resonant wire widths. We show that this
is due to the interplay between the shape resonances of the order parameter and
the sub-band energy spectrum induced by the lateral quantum confinement. These
effects can be used to manipulate the Josephson current, filter electrons by
subband and investigate the symmetries of the superconducting subbands.


title:
Classical Casimir-Polder force between polarizable microparticles and
  thin films including graphene

abstract:
  We derive analytic expressions for the classical Casimir-Polder free energy
and force for a polarizable (magnetizable) atom (microparticle) interacting
with thin films, made of different materials, or graphene. It is shown that for
an isolated dielectric film the free energy and force decrease quicker with
separation, as compared to the case of atom interacting with a thick plate
(semispace). For metallic films some peculiar features depending on the model
of a metal used are analyzed. For an atom interacting with graphene we
demonstrate that at room temperature the classical regime is achieved at about
$1.5\,\mu$m separation. In this regime the contributions to the free energy and
force due to atomic magnetic polarizability are suppressed, as compared to main
terms caused by the atomic electric polarizability. According to our results,
at separations above $5\,\mu$m the Casimir-Polder interaction of atoms with
graphene is of the same strength as with an ideal-metal plane. The classical
interaction of atoms with thin films deposited on substrates is also
considered.


title:
Do altmetrics correlate with citations? Extensive comparison of
  altmetric indicators with citations from a multidisciplinary perspective

abstract:
  An extensive analysis of the presence of different altmetric indicators
provided by Altmetric.com across scientific fields is presented, particularly
focusing on their relationship with citations. Our results confirm that the
presence and density of social media altmetric counts are still very low and
not very frequent among scientific publications, with 15%-24% of the
publications presenting some altmetric activity and concentrating in the most
recent publications, although their presence is increasing over time.
Publications from the social sciences, humanities and the medical and life
sciences show the highest presence of altmetrics, indicating their potential
value and interest for these fields. The analysis of the relationships between
altmetrics and citations confirms previous claims of positive correlations but
relatively weak, thus supporting the idea that altmetrics do not reflect the
same concept of impact as citations. Also, altmetric counts do not always
present a better filtering of highly cited publications than journal citation
scores. Altmetrics scores (particularly mentions in blogs) are able to identify
highly cited publications with higher levels of precision than journal citation
scores (JCS), but they have a lower level of recall. The value of altmetrics as
a complementary tool of citation analysis is highlighted, although more
research is suggested to disentangle the potential meaning and value of
altmetric indicators for research evaluation.


title:
Brunn-Minkowski inequality for the 1-Riesz capacity and level set
  convexity for the 1/2-Laplacian

abstract:
  We prove that that the 1-Riesz capacity satisfi es a Brunn-Minkowski
inequality, and that the capacitary function of the 1/2-Laplacian is level set
convex.


title: Globular clusters: a chemical roadmap between anomalies and homogeneity

abstract:
  For several decades, globular clusters have been considered the best example
of simple stellar populations, hosting coeval and chemical homogeneous stars.
The last decade of spectroscopic and photometric studies has revealed a more
complex view of their chemical composition, with a high level of homogeneity in
their iron content but star-to-star variations in some light elements. This
contribution summarizes the main evidence about the chemical anomalies in the
stellar content of the globular clusters, discussing also some peculiar objects
with intrinsic dispersions in their iron content.


title:
Dynamical phase transitions in Hegselmann-Krause model of opinion
  dynamics and consensus

abstract:
  The dynamics of the model of agents with limited confidence introduced by
Hegselmann and Krause exhibits multiple well-separated regimes characterised by
the number of distinct clusters in the stationary state. We present indications
that there are genuine dynamical phase transitions between these regimes. The
main indicator is the divergence of the average evolution time required to
reach the stationary state. The slowdown close to the transition is connected
with the emergence of the groups of mediator agents which are very small but
have decisive role in the process of social convergence. More detailed study
shows that the histogram of the evolution times is composed of several peaks.
These peaks are unambiguously interpreted as corresponding to mediator groups
consisting of one, two, three etc. agents. Detailed study reveals that each
transition possesses also an internal fine structure.


title: The dynamics of amplified spontaneous emission in CdSe/ZnSe quantum dots

abstract:
  We have used the variable stripe technique and pump-probe spectroscopy to
investigate both gain and the dynamics of amplified spontaneous emission from
CdSe quantum dot structures. We have found modal gain coefficients of 75 and 32
1/cm for asymmetric and symmetric waveguide structures, respectively. Amplified
spontaneous emission decay times of 150 and 300 ps and carrier capture times of
15 and 40 ps were measured for the structures with high and low material gains
respectively. The difference in the capture times are related to the fact that
for the symmetric waveguide, carriers diffuse into the active region from the
uppermost ZnMgSSe cladding layer, yielding a longer rise time for the
pump-probe signals for this sample.


title: Statistical Physics of Pure Barkhausen Noise

abstract:
  We discuss a model metallic glass in which Barkhausen Noise can be studied in
exquisite detail, free of thermal effects and of the rate of ramping of the
magnetic field. The mechanism of the jumps in magnetic moment that cause the
Barkhausen Noise can be fully understood as consecutive instabilities where an
eigenvalue of the Hessian matrix hits zero, leading to a magnetization jump
$\Delta m$ which is simultaneous with a stress and energy changes $\Delta
\sigma$ and $\Delta U$ respectively. Contrary to common belief we find no
"movements of magnetic domain boundaries" across pinning sites, no fractal
domains, no self-organized criticality and no exact scaling behaviour. We
present a careful numerical analysis of the statistical properties of the
phenomenon, and show that with every care taken this analysis is tricky, and
easily misleading. Without a guiding theory it is almost impossible to get the
right answer for the statistics of Barkhausen Noise. We therefore present an
analytic theory, showing that the probability distribution function (pdf) of
Barkhausen Noise is not a power law times an exponential cutoff.


title: Self-similarity and the Froissart bound

abstract:
  The Froissart bound implies that the total cross section (or, equivalently,
the structure function) cannot rise faster than the logarithmic growth of $
\ln^{2} \left(\frac{1}{x} \right)$. In this work, we show that such a slow
growth is not compatible with the notion of self-similarity. As a result, it
calls for the modification of the defining transverse-momentum-dependent parton
density function (TMD PDF) of a self-similarity based proton structure function
$F_{2} \left(x,Q^{2} \right)$ at small \textit{x}. Using plausible assumptions,
we obtain the Froissart saturation condition on this TMD PDF.


title: Structure of weighted Hardy spaces in the plane

abstract:
  We characterize certain weighted Hardy spaces on the unit disk and completely
describe their dual spaces.


title: A photon propagator on de Sitter in covariant gauges

abstract:
  We construct a de Sitter invariant photon propagator in general covariant
gauges. Our result is a natural generalization of the Allen-Jacobson photon
propagator in Feynman gauge. Our propagator reproduces the correct response to
a point static charge and the one-loop electromagnetic stress-energy tensor,
strongly suggesting that it is suitable for perturbative calculations on de
Sitter.


title: Algorithmic Introduction of Quantified Cuts

abstract:
  We describe a method for inverting Gentzen's cut-elimination in classical
first-order logic. Our algorithm is based on first computign a compressed
representation of the terms present in the cut-free proof and then cut-formulas
that realize such a compression. Finally, a proof using these cut-formulas is
constructed. This method allows an exponential compression of proof length. It
can be applied to the output of automated theorem provers, which typically
produce analytic proofs. An implementation is available on the web and
described in this paper.


title: Diversity of scales makes an advantage: The case of the Minority Game

abstract:
  We use the Minority Game as a testing frame for the problem of the emergence
of diversity in socio-economic systems. For the MG with heterogeneous impacts,
we show that the direct generalization of the usual agents' profit does not fit
some real-world situations. As a typical example we use the traffic formulation
of the MG. Taking into account vehicles of various lengths it can easily happen
that one of the roads is crowded by a few long trucks and the other contains
more drivers but still is less covered by vehicles. Most drivers are in the
shorter queue, so the majority win. To describe such situations, we generalized
the formula for agents' profit by explicitly introducing utility function
depending on an agent's impact. Then, the overall profit of the system may
become positive depending on the actual choice of the utility function. We
investigated several choices of the utility function and showed that this
variant of the MG may turn into a positive sum game.


title: Basepoint-free theorem of Reid--Fukuda type for quasi-log schemes

abstract:
  We introduce various new operations for quasi-log structures. Then we prove
the basepoint-free theorem of Reid--Fukuda type for quasi-log schemes as an
application.


title: Caps in $\mathbf{\mathbb{Z}_n^2}$

abstract:
  We consider point sets in $\mathbb{Z}_n^2$ where no three points are on a
line - also called caps or arcs. For the determination of caps with maximum
cardinality and complete caps with minimum cardinality we provide integer
linear programming formulations and identify some values for small $n$.


title: Nonlinearity enhancement in optomechnical system

abstract:
  The nonlinearity is an important feature in the field of optomechanics.
Employing atomic coherence, we put forward a scheme to enhance the nonlinearity
of the cavity optomechanical system. The effective Hamiltonian is derived,
which shows that the nonlinear strength can be enhanced by increasing the
number of atoms at certain range of parameters. We also numerically study the
nonlinearity enhancement beyond the effective Hamiltonian. Furthermore, we
investigate the potential usage of the nonlinearity in performing quantum
nondemolition (QND) measurement of the bosonic modes. Our results show that the
present system exhibits synchronization, and the nonlinear effects provide us
an effective method in performing QND.


title: On the Controllability and Observability of Networked Dynamic Systems

abstract:
  Some necessary and sufficient conditions are obtained for the controllability
and observability of a networked system with linear time invariant (LTI)
dynamics. The topology of this system is fixed but arbitrary, and every
subsystem is permitted to have different dynamic input-output relations. These
conditions essentially depend only on transmission zeros of every subsystem and
the connection matrix among subsystems, which makes them attractive in the
analysis and synthesis of a large scale networked system. As an application,
these conditions are utilized to characterize systems whose steady state
estimation accuracy with the distributed predictor developed in (Zhou, 2013) is
equal to that of the lumped Kalman filter. Some necessary and sufficient
conditions on system matrices are derived for this equivalence. It has been
made clear that to guarantee this equivalence, the steady state update gain
matrix of the Kalman filter must be block diagonal.


title: Mapping de Rham-Gabadadze-Tolley bigravity into braneworld setup

abstract:
  We discuss whether or not bigravity theory can be embedded into the
braneworld setup. As a candidate, we consider Dvali-Gabadadze-Porrati two-brane
model with the Goldberger-Wise radion stabilization. We will show that we can
construct a ghost free model whose low energy spectrum is composed of a
massless graviton and a massive graviton with a small mass. As is expected, the
behavior of this effective theory is shown to be identical to de
Rham-Gabadadze-Tolley bigravity. Unfortunately, this correspondence breaks down
at a relatively low energy due to the limitation of the adopted stabilization
mechanism.


title: On the Design of Fast Convergent LDPC Codes: An Optimization Approach

abstract:
  The complexity-performance trade-off is a fundamental aspect of the design of
low-density parity-check (LDPC) codes. In this paper, we consider LDPC codes
for the binary erasure channel (BEC), use code rate for performance metric, and
number of decoding iterations to achieve a certain residual erasure probability
for complexity metric. We first propose a quite accurate approximation of the
number of iterations for the BEC. Moreover, a simple but efficient utility
function corresponding to the number of iterations is developed. Using the
aforementioned approximation and the utility function, two optimization
problems w.r.t. complexity are formulated to find the code degree
distributions. We show that both optimization problems are convex. In
particular, the problem with the proposed approximation belongs to the class of
semi-infinite problems which are computationally challenging to be solved.
However, the problem with the proposed utility function falls into the class of
semi-definite programming (SDP) and thus, the global solution can be found
efficiently using available SDP solvers. Numerical results reveal the
superiority of the proposed code design compared to existing code designs from
literature.


title: The Feigin Tetrahedron

abstract:
  The first goal of this note is to extend the well-known Feigin homomorphisms
taking quantum groups to quantum polynomial algebras. More precisely, we define
generalized Feigin homomorphisms from a quantum shuffle algebra to quantum
polynomial algebras which extend the classical Feigin homomorphisms along the
embedding of the quantum group into said quantum shuffle algebra. In a recent
work of Berenstein and the author, analogous extensions of Feigin homomorphisms
from the dual Hall-Ringel algebra of a valued quiver to quantum polynomial
algebras were defined. To relate these constructions, we establish a
homomorphism, dubbed the quantum shuffle character, from the dual Hall-Ringel
algebra to the quantum shuffle algebra which relates the generalized Feigin
homomorphisms. These constructions can be compactly described by a commuting
tetrahedron of maps beginning with the quantum group and terminating in a
quantum polynomial algebra. The second goal in this project is to better
understand the dual canonical basis conjecture for skew-symmetrizable quantum
cluster algebras. In the symmetrizable types it is known that dual canonical
basis elements need not have positive multiplicative structure constants, while
this is still suspected to hold for skew-symmetrizable quantum cluster
algebras. We propose an alternate conjecture for the symmetrizable types: the
cluster monomials should correspond to irreducible characters of a KLR algebra.
Indeed, the main conjecture of this note would establish this "KLR conjecture"
for acyclic skew-symmetrizable quantum cluster algebras: that is, we conjecture
that the images of rigid representations under the quantum shuffle character
give irreducible characters for KLR algebras.


title: Information Flow Control in WebKit's JavaScript Bytecode

abstract:
  Websites today routinely combine JavaScript from multiple sources, both
trusted and untrusted. Hence, JavaScript security is of paramount importance. A
specific interesting problem is information flow control (IFC) for JavaScript.
In this paper, we develop, formalize and implement a dynamic IFC mechanism for
the JavaScript engine of a production Web browser (specifically, Safari's
WebKit engine). Our IFC mechanism works at the level of JavaScript bytecode and
hence leverages years of industrial effort on optimizing both the source to
bytecode compiler and the bytecode interpreter. We track both explicit and
implicit flows and observe only moderate overhead. Working with bytecode
results in new challenges including the extensive use of unstructured control
flow in bytecode (which complicates lowering of program context taints),
unstructured exceptions (which complicate the matter further) and the need to
make IFC analysis permissive. We explain how we address these challenges,
formally model the JavaScript bytecode semantics and our instrumentation, prove
the standard property of termination-insensitive non-interference, and present
experimental results on an optimized prototype.


title:
$2$-arcs of maximal size in the affine and the projective Hjelmslev
  plane over $\mathbb{Z}_{25}$

abstract:
  It is shown that the maximal size of a $2$-arc in the projective Hjelmslev
plane over $\mathbb{Z}_{25}$ is $21$, and the $(21,2)$-arc is unique up to
isomorphism. Furthermore, all maximal $(20,2)$-arcs in the affine Hjelmslev
plane over $\mathbb{Z}_{25}$ are classified up to isomorphism.


title:
Rare events analysis of temperature chaos in the Sherrington-Kirkpatrick
  model

abstract:
  We investigate the question of temperature chaos in the
Sherrington-Kirkpatrick spin glass model, applying to existing Monte Carlo data
a recently proposed rare events based data analysis method. Thanks to this new
method, temperature chaos is now observable for this model, even with the
limited size systems that can be currently simulated.


title:
Modelling a response as a function of high frequency count data: the
  association between physical activity and fat mass

abstract:
  We present a new statistical modelling approach where the response is a
function of high frequency count data. Our application is about investigating
the relationship between the health outcome fat mass and physical activity (PA)
measured by accelerometer. The accelerometer quantifies the intensity of
physical activity as counts per epoch over a given period of time. We use data
from the Avon longitudinal study of parents and children (ALSPAC) where
accelerometer data is available as a time series of accelerometer counts per
minute over seven days for a subset of children. In order to compare
accelerometer profiles between individuals and to reduce the high dimension a
functional summary of the profiles is used. We use the histogram as a
functional summary due to its simplicity, suitability and ease of
interpretation. Our model is an extension of generalised regression of scalars
on functions or signal regression. It allows also multi-dimensional functional
predictors and additive non-linear predictors for metric covariates. The
additive multidimensional functional predictors allow investigating specific
questions about whether the effect of PA varies over its intensity, by gender,
by time of day or by day of the week. The key feature of the model is that it
utilises the full profile of measured PA without requiring cut-points defining
intensity levels for light, moderate and vigorous activity. We show that the
(not necessarily causal) effect of PA is not linear and not constant over the
activity intensity. Also, there is little evidence to suggest that the effect
of PA intensity varies by gender or whether it happens on weekdays or on
weekends.


title:
Modification of phase structure of black D6 branes in a canonical
  ensemble and its origin

abstract:
  It is well known that charged black $Dp$ branes of type II string theory
share a universal phase structure of van der Waals$-$Maxwell liquid-gas type
except $D5$ and $D6$ branes. Interestingly, the phase structure of $D5$ and
$D6$ branes can be changed to the universal form with the inclusion of
particular delocalized charged lower-dimensional branes. For $D5$ branes one
needs to introduce delocalized $D1$ branes, and for $D6$ branes, one needs to
introduce delocalized $D0$ branes to obtain the universal structure. In a
previous paper [J. High Energy Phys. {\bf 04} (2013) 100] Lu with Wei study the
phase structure of black $D6$ branes with the introduction of delocalized $D0$
branes in a special case when their charges are equal and the dilaton charge
vanishes. In this paper, we look at the phase structure of the black $D6/D0$
system with the generic values of the parameters, which makes the analysis more
involved but the structure more rich. We also provide reasons why the
respective modifications of the phase structures to the universal form for the
black $D5$ and $D6$ branes occur when specific delocalized lower-dimensional
branes are introduced.


title: Cosmology: the search for twenty-four (or more) functions

abstract:
  We enumerate the 4(1+F)+2S independent arbitrary functions of space require
to describe a general relativistic cosmology containing an arbitrary number of
non-interacting fluid (F) and scalar fields (S). Results are also given for
arbitrary space dimension and for higher-order gravity theories, where the
number increases to 16+4F+2S. Both counts are subject to assumptions about
whether the dark energy is a cosmological constant. A more detailed analysis is
provided when global homogeneity is assumed and the functions become constants.
This situation is also studied in the case where the flat and open universes
have compact spatial topologies. This changes the relative generalities
significantly and places new constraints on the types of expansion anisotropy
that are permitted. The most general compact homogeneous universes containing
Friedmann models are spatially flat and described by 8+4F+2S constants.
Comparisons are made with the simple 6-parameter lambda-CDM model and physical
interpretations provided for the parameters needed to describe the most general
cosmological models.


title: A Preliminary Report on Search for Good Examples of Hall's Conjecture

abstract:
  This paper is a preliminary report on our search for new good examples of
Hall's Conjecture. We present a new algorithm that will detect all good
examples within a given search space. We have implemented the algorithm, and
our executions have so far found five new good examples.


title:
Temperature dependent Raman study of phonons of different symmetries in
  single crystal Bi2Se3

abstract:
  High quality single crystals of Bi2Se3 were grown using a modified Bridgman
technique, the detailed study were carried out using Raman spectroscopy and
characterized by Laue diffraction and high resolution transmission electron
microscopy. Polarized Raman scattering measurements were also carried out, and
both the A1g and A2g phonon modes showed strong polarization effect, which is
consistent with the theoretical prediction. The temperature dependent study (in
the temperature range 83 K to 523 K of Raman active modes were reported and
observed to follow a systematic red shift. The frequency of these phonon modes
are found to vary linearly with temperature and can be explained by first order
temperature co-efficient. The temperature co-efficient for A11g, E2g and A21g
modes were estimated to be -1.44*10-2, -1.94*10-2 and -1.95*10-2cm-1/K
respectively.


title: Scalar triplet flavored leptogenesis: a systematic approach

abstract:
  Type-II seesaw is a simple scenario in which Majorana neutrino masses are
generated by the exchange of a heavy scalar electroweak triplet. When endowed
with additional heavy fields, such as right-handed neutrinos or extra triplets,
it also provides a compelling framework for baryogenesis via leptogenesis. We
derive in this context the full network of Boltzmann equations for studying
leptogenesis in the flavored regime. To this end we determine the relations
which hold among the chemical potentials of the various particle species in the
thermal bath. This takes into account the SM Yukawa interactions of both
leptons and quarks as well as sphaleron processes which, depending on the
temperature, may be classified as faster or slower than the Hubble rate. We
find that when leptogenesis is enabled by the presence of an extra triplet,
lepton flavor effects allow the production of the $B-L$ asymmetry through
lepton number conserving CP asymmetries. This scenario becomes dominant as soon
as the triplets couple more to leptons than to SM scalar doublets. In this
case, the way the $B-L$ asymmetry is created through flavor effects is novel:
instead of invoking the effect of $L$-violating inverse decays faster than the
Hubble rate, it involves the effect of $L$-violating inverse decays slower than
the Hubble rate. We also analyze the more general situation where lepton number
violating CP asymmetries are present and actively participate in the generation
of the $B-L$ asymmetry, pointing out that as long as $L$-violating triplet
decays are still in thermal equilibrium when the triplet gauge scattering
processes decouple, flavor effects can be striking, allowing to avoid all
washout suppression effects from seesaw interactions. In this case the amount
of $B-L$ asymmetry produced is limited only by a universal gauge suppression
effect, which nevertheless goes away for large triplet decay rates.


title:
Integral point sets in higher dimensional affine spaces over finite
  fields

abstract:
  We consider point sets in the $m$-dimensional affine space $\mathbb{F}_q^m$
where each squared Euclidean distance of two points is a square in
$\mathbb{F}_q$. It turns out that the situation in $\mathbb{F}_q^m$ is rather
similar to the one of integral distances in Euclidean spaces. Therefore we
expect the results over finite fields to be useful for the Euclidean case.
  We completely determine the automorphism group of these spaces which
preserves integral distances. For some small parameters $m$ and $q$ we
determine the maximum cardinality $\mathcal{I}(m,q)$ of integral point sets in
$\mathbb{F}_q^m$. We provide upper bounds and lower bounds on
$\mathcal{I}(m,q)$. If we map integral distances to edges in a graph, we can
define a graph $\mathfrak{G}_{m,q}$ with vertex set $\mathbb{F}_q^m$. It turns
out that $\mathfrak{G}_{m,q}$ is strongly regular for some cases.


title: Programming balanced optical beam splitters in white paint

abstract:
  Wavefront shaping allows for ultimate control of light propagation in
multiple-scattering media by adaptive manipulation of incident waves. We shine
two separate wavefront-shaped beams on a layer of dry white paint to create two
enhanced output speckle spots of equal intensity. We experimentally confirm by
interference measurements that the output speckle spots are almost correlated
like the two outputs of an ideal balanced beam splitter. The observed
deviations from the phase behavior of an ideal beam splitter are analyzed with
a transmission matrix model. Our experiments demonstrate that wavefront shaping
in multiple-scattering media can be used to approximate the functionality of
linear optical devices with multiple inputs and outputs.


title:
A comparison between parallelization approaches in molecular dynamics
  simulations on GPUs

abstract:
  We test the performances of two different approaches to the computation of
forces for molecular dynamics simulations on Graphics Processing Units. A
"vertex-based" approach, where a computing thread is started per particle, is
compared to a newly proposed "edge-based" approach, where a thread is started
per each potentially non-zero interaction. We find that the former is more
efficient for systems with many simple interactions per particle, while the
latter is more efficient if the system has more complicated interactions or
fewer of them. By comparing computation times on more and less recent GPU
technology, we predict that, if the current trend of increasing the number of
processing cores - as opposed to their computing power - remains, the
"edge-based" approach will gradually become the most efficient choice in an
increasing number of cases.


title: A Fractional Fokker-Planck Model for Anomalous Diffusion

abstract:
  In this paper we present a study of anomalous diffusion using a Fokker-Planck
description with fractional velocity derivatives. The distribution functions
are found using numerical means for varying degree of fractionality observing
the transition from a Gaussian distribution to a L\'evy distribution. The
statistical properties of the distribution functions are assessed by a
generalized expectation measure and entropy in terms of Tsallis statistical
mechanics. We find that the ratio of the generalized entropy and expectation is
increasing with decreasing fractionality towards the well known so-called
sub-diffusive domain, indicating a self-organising behavior.


title:
The $O(\alpha_s^2)$ Heavy Quark Corrections to Charged Current
  Deep-Inelastic Scattering at large Virtualities

abstract:
  We calculate the $O(\alpha_s^2)$ heavy flavor corrections to charged current
deep-inelastic scattering at large scales $Q^2 \gg m^2$. The contributing
Wilson coefficient are given as convolutions between massive operator matrix
elements and massless Wilson coefficients. Foregoing results in the literature
are extended and corrected. Numerical results are presented for the kinematic
region of the HERA data.


title:
Perturbative Description of the Fermionic Projector: Normalization,
  Causality and Furry's Theorem

abstract:
  The causal perturbation expansion of the fermionic projector is performed
with a contour integral method. Different normalization conditions are
analyzed. It is shown that the corresponding light-cone expansions are causal
in the sense that they only involve bounded line integrals. For the resulting
loop diagrams we prove a generalized Furry theorem.


title: Strong RR Lyrae excess in the Hercules-Aquila Cloud

abstract:
  We map the large-scale sub-structure in the Galactic stellar halo using
accurate 3D positions of ~14,000 RR Lyrae reported by the Catalina Sky Survey.
In the heliocentric distance range of 10-25 kpc, in the region of the sky
approximately bounded by 30{\deg} < l < 55{\deg} and -45{\deg} < b < -25{\deg},
there appears to be a strong excess of RRab stars. This overdensity, peaking at
18 kpc, is most likely associated with the so-called Hercules-Aquila Cloud,
previously detected using Main Sequence tracers at similar distances in the
Sloan Digital Sky Survey data. Our analysis of the period-amplitude
distribution of RR Lyrae in this region indicates that the HAC is dominated by
the Oosterhoff I type population. By comparing the measured RR Lyrae number
density to models of a smooth stellar halo, we estimate the significance of the
observed excess and provide an updated estimate of the total luminosity of the
Cloud's progenitor.


title:
Scalar products in models with $GL(3)$ trigonometric $R$-matrix. General
  case

abstract:
  We study quantum integrable models with $GL(3)$ trigonometric $R$-matrix
solvable by the nested algebraic Bethe ansatz. We analyze scalar products of
generic Bethe vectors and obtain an explicit representation for them in terms
of a sum with respect to partitions of Bethe parameters. This representation
generalizes known formula for the scalar products in the models with
$GL(3)$-invariant $R$-matrix.


title: Why bouncing droplets are a pretty good model of quantum mechanics

abstract:
  In 2005, Couder, Protiere, Fort and Badouad showed that oil droplets bouncing
on a vibrating tray of oil can display nonlocal interactions reminiscent of the
particle-wave associations in quantum mechanics; in particular they can move,
attract, repel and orbit each other. Subsequent experimental work by Couder,
Fort, Protiere, Eddi, Sultan, Moukhtar, Rossi, Molacek, Bush and Sbitnev has
established that bouncing drops exhibit single-slit and double-slit
diffraction, tunnelling, quantised energy levels, Anderson localisation and the
creation/annihilation of droplet/bubble pairs.
  In this paper we explain why. We show first that the surface waves guiding
the droplets are Lorentz covariant with the characteristic speed c of the
surface waves; second, that pairs of bouncing droplets experience an
inverse-square force of attraction or repulsion according to their relative
phase, and an analogue of the magnetic force; third, that bouncing droplets are
governed by an analogue of Schroedinger's equation where Planck's constant is
replaced by an appropriate constant of the motion; and fourth, that orbiting
droplet pairs exhibit spin-half symmetry and align antisymmetrically as in the
Pauli exclusion principle. Our analysis explains the similarities between
bouncing-droplet experiments and the behaviour of quantum-mechanical particles.
It also enables us to highlight some differences, and to predict some
surprising phenomena that can be tested in feasible experiments.


title:
Ab Initio Simulation of Electrical Currents Induced by Ultrafast Laser
  Excitation of Dielectric Materials

abstract:
  We theoretically investigate the generation of ultrafast currents in
insulators induced by strong few-cycle laser pulses. Ab initio simulations
based on time-dependent density functional theory give insight into the
atomic-scale properties of the induced current signifying a femtosecond-scale
insulator-metal transition. We observe the transition from nonlinear
polarization currents during the laser pulse at low intensities to
tunnelinglike excitation into the conduction band at higher laser intensities.
At high intensities, the current persists after the conclusion of the laser
pulse considered to be the precursor of the dielectric breakdown on the
femtosecond scale. We show that the transferred charge sensitively depends on
the orientation of the polarization axis relative to the crystal axis
suggesting that the induced charge separation reflects the anisotropic
electronic structure. We find good agreement with very recent experimental data
on the intensity and carrierenvelope phase dependence [A. Schiffrin et al.,
Nature (London) 493, 70 (2013)].

categories: cond-mat.mtrl-sci cond-mat.mes-hall physics.comp-ph physics.optics


title: Coordinate Bethe Ans\"atze for non-diagonal boundaries

abstract:
  Talk given at "Quantum Integrable Systems and Geometry" (3-7 September 2012,
Olhao, Portugal) and based on joint works with S. Belliard, N. Crampe and D.
Simon, see arXiv:1009.4119, arXiv:1105.4119, arXiv:1106.3264 and
arXiv:1209.4269.
  This short note presents only the basic ideas of the technique, and does not
attend to give a general overview of the subject. Interested readers should
refer to the original papers and references therein.


title: Controlled lasing from active optomechanical resonators

abstract:
  Planar microcavities with distributed Bragg reflectors (DBRs) host, besides
confined optical modes, also mechanical resonances due to stop bands in the
phonon dispersion relation of the DBRs. These resonances have frequencies in
the sub-terahertz (10E10-10E11 Hz) range with quality factors exceeding 1000.
The interaction of photons and phonons in such optomechanical systems can be
drastically enhanced, opening a new route toward manipulation of light. Here we
implemented active semiconducting layers into the microcavity to obtain a
vertical-cavity surface-emitting laser (VCSEL). Thereby three resonant
excitations -photons, phonons, and electrons- can interact strongly with each
other providing control of the VCSEL laser emission: a picosecond strain pulse
injected into the VCSEL excites long-living mechanical resonances therein. As a
result, modulation of the lasing intensity at frequencies up to 40 GHz is
observed. From these findings prospective applications such as THz laser
control and stimulated phonon emission may emerge.


title: 3-regular matchstick graphs with given girth

abstract:
  We consider 3-regular planar matchstick graphs, i.e. those which have a
planar embedding such that all edge lengths are equal, with given girth g. For
girth 3 it is known that such graphs exist if and only if the number of
vertices n is an even integer larger or equal to 8. Here we prove that such
graphs exist for girth g=4 if and only if n is even and at least 20. We provide
an example for girth g=5 consisting of 180 vertices.


title:
On hyperlogarithms and Feynman integrals with divergences and many
  scales

abstract:
  It was observed that hyperlogarithms provide a tool to carry out Feynman
integrals. So far, this method has been applied successfully to finite
single-scale processes. However, it can be employed in more general situations.
We give examples of integrations of three- and four-point integrals in
Schwinger parameters with non-trivial kinematic dependence, involving setups
with off-shell external momenta and differently massive internal propagators.
The full set of Feynman graphs admissible to parametric integration is not yet
understood and we discuss some counterexamples to the crucial property of
linear reducibility. Furthermore we clarify how divergent integrals can be
approached in dimensional regularization with this algorithm.


title: Curvature suppresses the Rayleigh-Taylor instability

abstract:
  The dynamics of a thin liquid film on the underside of a curved cylindrical
substrate is studied. The evolution of the liquid layer is investigated as the
film thickness and the radius of curvature of the substrate are varied. A
dimensionless parameter (a modified Bond number) that incorporates both
geometric parameters, gravity, and surface tension is identified, and allows
the observations to be classified according to three different flow regimes:
stable films, films with transient growth of perturbations followed by decay,
and unstable films. Experiments and theory confirm that, below a critical value
of the Bond number, curvature of the substrate suppresses the Rayleigh-Taylor
instability.


title: Maxima Q-index of graphs with forbidden odd cycles

abstract:
  Let $q\left( G\right) $ be the $Q$-index (the largest eigenvalue of the
signless Laplacian) of $G$. Let $S_{n,k}$ be the graph obtained by joining each
vertex of a complete graph of order $k$ to each vertex of an independent set of
order $n-k.$ The main result of this paper is the following theorem:
  Let $k\geq3,$ $n\geq110k^{2},$ and $G$ be a graph of order $n$. If $G$ has no
$C_{2k+1},$ then $q\left( G\right) <q\left( S_{n,k}\right) ,$ unless
$G=S_{n,k}.$
  This result proves the odd case of the conjecture in [M.A.A. de Freitas, V.
Nikiforov, and L. Patuzzi, Maxima of the $Q$-index: forbidden $4$-cycle and
$5$-cycle, \emph{Electron. J. Linear Algebra }26 (2013), 905-916.]


title:
Correlation between Dark Matter and Dark Radiation in String
  Compactifications

abstract:
  Reheating in string compactifications is generically driven by the decay of
the lightest modulus which produces Standard Model particles, dark matter and
light hidden sector degrees of freedom that behave as dark radiation. This
common origin allows us to find an interesting correlation between dark matter
and dark radiation. By combining present upper bounds on the effective number
of neutrino species N_eff with lower bounds on the reheating temperature as a
function of the dark matter mass m_DM from Fermi data, we obtain strong
constraints on the (N_eff,m_DM)-plane. Most of the allowed region in this plane
corresponds to non-thermal scenarios with Higgsino-like dark matter. Thermal
dark matter can be allowed only if N_eff tends to its Standard Model value. We
show that the above situation is realised in models with perturbative moduli
stabilisation where the production of dark radiation is unavoidable since bulk
closed string axions remain light and do not get eaten up by anomalous U(1)s.


title: More eigenvalue problems of Nordhaus-Gaddum type

abstract:
  Let $G$ be a graph of order $n$ and let $\mu_{1}\left(G\right) \geq
\cdots\geq\mu_{n}\left(G\right) $ be the eigenvalues of its adjacency matrix.
This note studies eigenvalue problems of Nordhaus-Gaddum type. Let
$\overline{G}$ be the complement of a graph $G.$ It is shown that if $s\geq2$
and $n\geq15\left(s-1\right) ,$ then \[ \left\vert \mu_{s}\left(G\right)
\right\vert +|\mu_{s}(\overline{G})|\,\leq n/\sqrt{2\left(s-1\right)}-1. \]
  Also if $s\geq1$ and $n\geq4^{s},$ then \[ \left\vert
\mu_{n-s+1}\left(G\right) \right\vert +|\mu_{n-s+1}(\overline {G})|\,\leq
n/\sqrt{2s}+1. \] If $s=2^{k}+1$ for some integer $k$, these bounds are
asymptotically tight. These results settle infinitely many cases of a general
open problem.


title:
Modular data and regularity of Monge-Amp\`ere exhaustions and of
  Kobayashi distance

abstract:
  Regularity properties of intrinsic objects for a large class of Stein
Manifolds, namely of Monge-Amp\`ere exhaustions and Kobayashi distance, is
interpreted in terms of modular data. The results lead to a construction of an
infinite dimensional family of convex domains with squared Kobayashi distance
of prescribed regularity properties. A new sharp refinement of Stoll's
characterization of $\mathbb C^n$ is also given.


title: Enumeration of plane partitions with a restricted number of parts

abstract:
  In the paper, the quantum-statistical approach is used to estimate the number
of restricted plane partitions of an integer $n$ with the number of parts not
exceeding some finite $N$. The analogy between this number-theoretical problem
and the enumeration of microstates of the ideal two-dimensional Bose-gas is
used. The conjectured expression for the number of restricted plane partitions
shows a good agreement between calculated and exact values for $n=10\div20$.


title: Proof of Bertrand's Postulate for $n\geq 6$

abstract:
  We add a few ideas to Erd\H{o}s's proof of Bertrand's Postulate to produce
one using a little calculus but requiring direct check only for $n\leq 5$ and
one without using calculus and requiring direct check only for $n\leq 12$. The
proofs can be presented to high school students.


title:
Delayed acceptance particle MCMC for exact inference in stochastic
  kinetic models

abstract:
  Recently-proposed particle MCMC methods provide a flexible way of performing
Bayesian inference for parameters governing stochastic kinetic models defined
as Markov (jump) processes (MJPs). Each iteration of the scheme requires an
estimate of the marginal likelihood calculated from the output of a sequential
Monte Carlo scheme (also known as a particle filter). Consequently, the method
can be extremely computationally intensive. We therefore aim to avoid most
instances of the expensive likelihood calculation through use of a fast
approximation. We consider two approximations: the chemical Langevin equation
diffusion approximation (CLE) and the linear noise approximation (LNA). Either
an estimate of the marginal likelihood under the CLE, or the tractable marginal
likelihood under the LNA can be used to calculate a first step acceptance
probability. Only if a proposal is accepted under the approximation do we then
run a sequential Monte Carlo scheme to compute an estimate of the marginal
likelihood under the true MJP and construct a second stage acceptance
probability that permits exact (simulation based) inference for the MJP. We
therefore avoid expensive calculations for proposals that are likely to be
rejected. We illustrate the method by considering inference for parameters
governing a Lotka-Volterra system, a model of gene expression and a simple
epidemic process.


title: Weighted Ostrowski Type inequality Involving Integral Means

abstract:
  The ostrowski inequality expresses bounds on the deviation of a function from
its integral mean. The aim of this paper is to establish a new inequality using
weight function which generalizes the inequalities of Dragomir, Wang and Cerone
.The current article obtains bounds for the deviation of a function from a
combination of integral means over the end intervals covering the entire
interval. A variety of earlier results are recaptured as particular instances
of the current development. Applications for cumulative distribution function
are also discussed.


title:
Bethe vectors of gl(3)-invariant integrable models, their scalar
  products and form factors

abstract:
  This short note corresponds to a talk given at "Lie Theory and Its
Applications in Physics", (Varna, Bulgaria, June 2013) and is based on joint
works with S. Belliard, S. Pakuliak and N. Slavnov, see arXiv:1206.4931,
arXiv:1207.0956, arXiv:1210.0768, arXiv:1211.3968 and arXiv:1312.1488.


title: Regular matchstick graphs

abstract:
  A graph G=(V,E) is called a unit-distance graph in the plane if there is an
injective embedding of V in the plane such that every pair of adjacent vertices
are at unit distance apart. If additionally the corresponding edges are
non-crossing and all vertices have the same degree r we talk of a regular
matchstick graph. Due to Euler's polyhedron formula we have $r\le 5$. The
smallest known 4-regular matchstick graph is the so called Harborth graph
consisting of 52 vertices. In this article we prove that no finite 5-regular
matchstick graph exists and provide a lower bound for the number of vertices of
4-regular matchstick graphs.


title:
Exact Divisibility of Exponential Sums Associated to Binomials over
  finite fields

abstract:
  In this paper we compute the exact divisibility of exponential sums
associated to binomials $F(X)=aX^{d_1} +b X^{d_2}$. In particular, for the case
where $\max\{d_1,d_2\}\leq\sqrt{p-1}$, the exact divisibility is computed. As a
byproduct of our results, we obtain families of binomials that do not permute
$\mathbb{F}_p$, and a lower bound for the sizes of value sets of binomials over
$\mathbb{F}_p$. Additionally, we obtain a new criterion to determine if a
polynomial defines or not a permutation of $\mathbb{F}_p$ that depends on the
divisibility of the exponential sum associated to the polynomial.


title: Weak MSO: Automata and Expressiveness Modulo Bisimilarity

abstract:
  We prove that the bisimulation-invariant fragment of weak monadic
second-order logic (WMSO) is equivalent to the fragment of the modal
$\mu$-calculus where the application of the least fixpoint operator $\mu
p.\varphi$ is restricted to formulas $\varphi$ that are continuous in $p$. Our
proof is automata-theoretic in nature; in particular, we introduce a class of
automata characterizing the expressive power of WMSO over tree models of
arbitrary branching degree. The transition map of these automata is defined in
terms of a logic $\mathrm{FOE}_1^\infty$ that is the extension of first-order
logic with a generalized quantifier $\exists^\infty$, where $\exists^\infty x.
\phi$ means that there are infinitely many objects satisfying $\phi$. An
important part of our work consists of a model-theoretic analysis of
$\mathrm{FOE}_1^\infty$.


title: Fast regocnition of planar non unit distance graphs

abstract:
  We study criteria attesting that a given graph can not be embedded in the
plane so that neighboring vertices are at unit distance apart and the straight
line edges do not cross.


title:
Importance of relativistic effects in electronic structure and
  thermopower calculations for Mg2Si, Mg2Ge and Mg2Sn

abstract:
  We present a theoretical study of the influence of the relativistic effects
on electronic band structure and thermopower of Mg2X(X= Si, Ge, Sn)
semiconductors. The full potential Korringa-Kohn-Rostoker (KKR) method is used,
and the detailed comparison between the fully relativistic and
semi-relativistic electronic structure features is done. We show that the
spin-orbit (S-O) interaction splits the valence band structure at Gamma point
in good agreement with the experimental data, and this effect strongly depends
on X atom. The S-O modifications of the topology of the Gamma-centered
hole-like Fermi surface pockets lead to a change in electron transport
properties, which are investigated using the Boltzmann approach. In addition,
the simple and efficient method is presented for the calculation of density of
states effective mass m*, and then used to examine the impact of relativistic
effects on m*. It is found that S-O coupling of the valence bands reduces
effective mass and therefore significantly lowers the thermopower, primarily in
Mg2Sn, but also in Mg2Ge. A detrimental influence of the S-O interaction on
thermoelectric performance of p-type Mg2X is analyzed in function of
temperature (10-900 K) and carrier concentration (10^18-10^22 cm-3).
Interestingly, similar calculations in n-type Mg2X, show negligible effect of
the S-O interaction on lowest conduction bands and consequently also on the
Seebeck coefficient.


title: A lower bound for 4-regular planar unit distance graphs

abstract:
  We perform an exhaustive search for the minimum 4-regular unit distance graph
resulting in a lower bound of 34 vertices.


title:
Transient times, resonances and drifts of attractors in dissipative
  rotational dynamics

abstract:
  In a dissipative system the time to reach an attractor is often influenced by
the peculiarities of the model and in particular by the strength of the
dissipation. In particular, as a dissipative model we consider the spin-orbit
problem providing the dynamics of a triaxial satellite orbiting around a
central planet and affected by tidal torques. The model is ruled by the
oblateness parameter of the satellite, the orbital eccentricity, the
dissipative parameter and the drift term. We devise a method which provides a
reliable indication on the transient time which is needed to reach an attractor
in the spin-orbit model; the method is based on an analytical result, precisely
a suitable normal form construction. This method provides also information
about the frequency of motion. A variant of such normal form used to
parametrize invariant attractors provides a specific formula for the drift
parameter, which in turn yields a constraint - which might be of interest in
astronomical problems - between the oblateness of the satellite and its orbital
eccentricity.


title: Emergent Majorana Mass and Axion Couplings in Superfluids

abstract:
  Axions (in the general sense) may acquire qualitatively new couplings inside
superfluids. Their conventional couplings to fermions, in empty space, involve
purely imaginary masses; the new couplings involve emergent Majorana masses.
The possibility of weak links for axions, recently put forward, is analyzed,
rejected, and replaced with a non-local analogue.


title:
Invariant Discretization of Partial Differential Equations Admitting
  Infinite-Dimensional Symmetry Groups

abstract:
  Given a differential equation with infinite-dimensional symmetry pseudo-group
it is shown, using an example, that it is generally not possible to construct
enough joint invariants to form an invariant numerical scheme of the equation.
To circumvent this problem, we propose to discretize the symmetry pseudo-group
action. Using the theory of moving frames, joint invariants of the discretized
action are algorithmically constructed. Computer simulations indicate that
numerical schemes constructed from these joint invariants can produce better
numerical results than standard schemes.


title:
Intelligent Techniques for Resolving Conflicts of Knowledge in
  Multi-Agent Decision Support Systems

abstract:
  This paper focuses on some of the key intelligent techniques for conflict
resolution in Multi-Agent Decision Support Systems.


title: The UV view of multi spin galaxies: insight from SPH simulations

abstract:
  The UV images of GALEX revealed that ~30% of Early Type Galaxies (ETG) show
UV emission indicating a rejuvenation episode. In ETGs with multiple spin
components this percentage increases at 50%. We present here the
characteristics of this sample and our smooth particle hydrodynamic (SPH)
simulations with chemo-photometric implementation that provide dynamical and
morphological information together with the spectral energy distribution (SED)
at each evolutionary stage. We show our match of the global properties of two
ETGs (e.g. NGC 3626 and NGC 5173). For these galaxies we can trace their
evolutionary path.


title: On the Hegselmann-Krause conjecture in opinion dynamics

abstract:
  We give an elementary proof of a conjecture by Hegselmann and Krause in
opinion dynamics, concerning a symmetric bounded confidence interval model: If
there is a truth and all individuals take each other seriously by a positive
amount bounded away from zero, then all truth seekers will converge to the
truth. Here truth seekers are the individuals which are attracted by the truth
by a positive amount. In the absence of truth seekers it was already shown by
Hegselmann and Krause that the opinions of the individuals converge.


title: On the threshold for the Maker-Breaker $H$-game

abstract:
  We study the Maker-Breaker $H$-game played on the edge set of the random
graph $G_{n,p}$. In this game two players, Maker and Breaker, alternately claim
unclaimed edges of $G_{n,p}$, until all the edges are claimed. Maker wins if he
claims all the edges of a copy of a fixed graph $H$; Breaker wins otherwise. In
this paper we show that, with the exception of trees and triangles, the
threshold for an $H$-game is given by the threshold of the corresponding Ramsey
property of $G_{n,p}$ with respect to the graph $H$.