title:
Integration of knowledge to support automatic object reconstruction from
  images and 3D data

abstract:
  Object reconstruction is an important task in many fields of application as
it allows to generate digital representations of our physical world used as
base for analysis, planning, construction, visualization or other aims. A
reconstruction itself normally is based on reliable data (images, 3D point
clouds for example) expressing the object in his complete extent. This data
then has to be compiled and analyzed in order to extract all necessary
geometrical elements, which represent the object and form a digital copy of it.
Traditional strategies are largely based on manual interaction and
interpretation, because with increasing complexity of objects human
understanding is inevitable to achieve acceptable and reliable results. But
human interaction is time consuming and expensive, why many researches has
already been invested to use algorithmic support, what allows to speed up the
process and to reduce manual work load. Presently most of such supporting
algorithms are data-driven and concentate on specific features of the objects,
being accessible to numerical models. By means of these models, which normally
will represent geometrical (flatness, roughness, for example) or physical
features (color, texture), the data is classified and analyzed. This is
successful for objects with low complexity, but gets to its limits with
increasing complexness of objects. Then purely numerical strategies are not
able to sufficiently model the reality. Therefore, the intention of our
approach is to take human cognitive strategy as an example, and to simulate
extraction processes based on available human defined knowledge for the objects
of interest. Such processes will introduce a semantic structure for the objects
and guide the algorithms used to detect and recognize objects, which will yield
a higher effectiveness. Hence, our research proposes an approach using
knowledge to guide the algorithms in 3D point cloud and image processing.


title: Multiquark states in the covariant quark confinement model

abstract:
  This talk reviews the last applications of the covariant quark model for
studying the properties of the multiquark states: B_s-meson (quark-antiquark
state), light baryons (three-quark states) and tetraquark (four-quark state).
The form factors of the B(B_s)-> P(V)-transitions are evaluated in the full
kinematical region of momentum transfer squared. The widths of some
B_s-nonleptonic decays are calculated. The static properties of the proton and
neutron, and the \Lambda-hyperon (magnetic moments and charge radii) and the
behavior of the nucleon form factors at low momentum transfers are described.
The consequences of treating the X(3872) meson as a tetraquark bound state are
explored. The decay widths of the observed channels X->J/\psi+2\pi (3\pi) and
X-> \bar D^0 + D^0+\pi^0 via the intermediate off--shell states X->
J/\psi+\rho(\omega) and X-> \bar D + D^* are calculated. Its one-photon decay
X-> \gamma+ J/\psi is also analyzed.


title: Horizontal Visibility graphs generated by type-I intermittency

abstract:
  The type-I intermittency route to (or out of) chaos is investigated within
the Horizontal Visibility graph theory. For that purpose, we address the
trajectories generated by unimodal maps close to an inverse tangent bifurcation
and construct, according to the Horizontal Visibility algorithm, their
associated graphs. We show how the alternation of laminar episodes and chaotic
bursts has a fingerprint in the resulting graph structure. Accordingly, we
derive a phenomenological theory that predicts quantitative values of several
network parameters. In particular, we predict that the characteristic power law
scaling of the mean length of laminar trend sizes is fully inherited in the
variance of the graph degree distribution, in good agreement with the numerics.
We also report numerical evidence on how the characteristic power-law scaling
of the Lyapunov exponent as a function of the distance to the tangent
bifurcation is inherited in the graph by an analogous scaling of the block
entropy over the degree distribution. Furthermore, we are able to recast the
full set of HV graphs generated by intermittent dynamics into a renormalization
group framework, where the fixed points of its graph-theoretical RG flow
account for the different types of dynamics. We also establish that the
nontrivial fixed point of this flow coincides with the tangency condition and
that the corresponding invariant graph exhibit extremal entropic properties.

categories: nlin.CD cond-mat.stat-mech math-ph math.MP physics.data-an


title: Hyperplane arrangements and Milnor fibrations

abstract:
  There are several topological spaces associated to a complex hyperplane
arrangement: the complement and its boundary manifold, as well as the Milnor
fiber and its own boundary. All these spaces are related in various ways,
primarily by a set of interlocking fibrations. We use cohomology with
coefficients in rank 1 local systems on the complement of the arrangement to
gain information on the homology of the other three spaces, and on the
monodromy operators of the various fibrations.


title: Debye relaxation and 250 K anomaly in glass forming monohydroxy alcohols

abstract:
  A previous dielectric, near-infrared (NIR), and nuclear magnetic resonance
study on the hydrogen-bonded liquid 2-ethyl-1-hexanol [C. Gainaru et al., Phys.
Rev. Lett. 107, 118304 (2011)] revealed anomalous behavior in various static
quantities near 250 K. To check whether corresponding observations can be made
for other monohydroxy alcohols as well, these experimental methods were applied
to such substances with 5, 6, 7, 8, and 10 carbon atoms in their molecular
backbone. All studied liquids exhibit a change of behavior near 250 K which is
tentatively ascribed to effects of hydrogen bond cooperativity. By analyzing
the NIR band intensities, a linear cluster size is derived that agrees with
estimates from dielectric spectroscopy. All studied alcohols, except
4-methyl-3-heptanol, display a dominant Debye-like peak. Furthermore, neat
2-ethyl-1-butanol exhibits a well resolved structural relaxation in its
dielectric loss spectrum which so far has only been observed for diluted
monohydroxy alcohols.


title:
New quantitative estimates on the incidence geometry and growth of
  finite sets

abstract:
  This thesis establishes new quantitative records in several problems of
incidence geometry and growth. After the necessary background in Chapters 1, 2
and 3, the following results are proven.
  Chapter 4 gives new results in the incidence geometry of a plane determined
by a finite field of prime order. These comprise a new upper bound on the total
number of incidences determined by finitely many points and lines, and a new
estimate for the number of distinct lines determined by a finite set of
non-collinear points.
  Chapter 5 gives new results on expander functions. First, a new bound is
established for the two-variable expander a+ab over a finite field of prime
order. Second, new expanders in three and four variables are demonstrated over
the real and complex numbers with stronger growth properties than any functions
previously considered.
  Finally, Chapter 6 gives the first bespoke sum-product estimate over function
fields, a setting that has so far been largely unexplored for these kinds of
problems. This last chapter is joint work with Thomas Bloom.


title:
Operational derivation of Maxwell-Boltzmann distribution with Maxwell's
  demon model

abstract:
  The resolution of the Maxwell's demon paradox linked thermodynamics with
information theory through information erasure principle. By considering a
demon endowed with a Turing-machine consisting of a memory tape and a
processor, we attempt to explore the link towards the foundations of
statistical mechanics and to derive results therein in an "operational" manner.
Here, we present a derivation of the Boltzmann distribution in equilibrium as
an example, without hypothesizing the principle of maximum entropy. Further,
since the model can be applied to non-equilibrium processes, in principle, we
demonstrate the dissipation-fluctuation relation to show the possibility in
this direction.


title: Modeling IR SED of AGN with Spitzer and Herschel data

abstract:
  One of the remaining open issues in the context of the analysis of Active
Galactic Nuclei (AGN) is the evidence that nuclear gravitational accretion is
often accompanied by a concurrent starburst (SB) activity. What is, in this
picture, the role played by the obscuring dust around the nucleus and what do
the state of the art AGN torus models have to say? Can the IR data provided by
Spitzer and Herschel help us in extensively investigate both phenomena and, if
so, how and with what limitations? In this paper we present our contribution to
the efforts of answering these questions. We show some of the main results
coming from a comparative study of various AGN SED modeling approaches,
focusing mostly on the much-debated issue about the morphology of the dust
distribution in the toroidal structure surrounding the AGN. We found that the
properties of dust in AGN as measured by matching observations (be it broad
band IR photometry or IR spectra) with models, strongly depend on the choiceof
the dust distribution. Then, we present the spectral energy distribution (SED)
fitting procedure we developed, making make the best use of Spitzer and
Herschel SPIRE mid- and far-IR observations, to dig into the role played by the
possible presence of an AGN on the host galaxy's properties.


title:
A double-peaked outburst of A 0535+26 observed with INTEGRAL, RXTE, and
  Suzaku

abstract:
  The Be/X-ray binary A 0535+26 showed a normal (type I) outburst in August
2009. It is the fourth in a series of normal outbursts associated with the
periastron, but is unusual by presenting a double-peaked light curve. The two
peaks reached a flux of ~450 mCrab in the 15-50 keV range. We present results
of the timing and spectral analysis of INTEGRAL, RXTE, and Suzaku observations
of the outburst. The energy dependent pulse profiles and their evolution during
the outburst are studied. No significant differences with respect to other
normal outbursts are observed. The centroid energy of the fundamental cyclotron
line shows no significant variation during the outburst. A spectral hardening
with increasing luminosity is observed. We conclude that the source is
accreting in the sub-critical regime. We discuss possible explanations for the
double-peaked outburst.


title:
High Jaynes-Cummings pseudospins eigenstates in the homogeneous
  Tavis-Cummings model

abstract:
  We show that a set of N identical qubits coupled to a single cavity resonator
can be decomposed into a set of independent subsystems, which can be thought of
as higher pseudospin generalisations of the Jaynes-Cummings model. We derive
and analyse the solutions to the equations of motion and demonstrate unusual
beating behaviour resulting from a new form of square-root-n-type non-linearity
appearing within a pseudospin ladder. Furthermore, we propose a relative phase
shift transformation which allows one to switch/initiate the multi-qubit state
in a desired pseudospin configuration, and show how such transformations can be
used to undo spontaneous single qubit decay. We discuss the conditions which
justify the validity of the rotating wave approximation in an N-qubit system.


title:
A DSL for Mapping Abstract Syntax Models to Concrete Syntax Models in
  ModelCC

abstract:
  ModelCC is a model-based parser generator that decouples language design from
language processing. ModelCC provides two different mechanisms to specify the
mapping from an abstract syntax model to a concrete syntax model: metadata
annotations defined on top of the abstract syntax model specification and a
domain-specific language for defining ASM-CSM mappings. Using a domain-specific
language to specify the mapping from abstract to concrete syntax models allows
the definition of multiple concrete syntax models for the same abstract syntax
model. In this paper, we describe the ModelCC domain-specific language for
abstract syntax model to concrete syntax model mappings and we showcase its
capabilities by providing a meta-definition of that domain-specific language.


title:
Anomalies in low-energy Gamma-Ray Burst spectra with the Fermi Gamma-Ray
  Burst Monitor

abstract:
  A Band function has become the standard spectral function used to describe
the prompt emission spectra of gamma-ray bursts (GRBs). However, deviations
from this function have previously been observed in GRBs detected by BATSE and
in individual GRBs from the \textit{Fermi} era. We present a systematic and
rigorous search for spectral deviations from a Band function at low energies in
a sample of the first two years of high fluence, long bursts detected by the
\textit{Fermi} Gamma-Ray Burst Monitor (GBM). The sample contains 45 bursts
with a fluence greater than 2$\times10^{-5}$ erg / cm$^{2}$ (10 - 1000 keV). An
extrapolated fit method is used to search for low-energy spectral anomalies,
whereby a Band function is fit above a variable low-energy threshold and then
the best fit function is extrapolated to lower energy data. Deviations are
quantified by examining residuals derived from the extrapolated function and
the data and their significance is determined via comprehensive simulations
which account for the instrument response. This method was employed for both
time-integrated burst spectra and time-resolved bins defined by a signal to
noise ratio of 25 $\sigma$ and 50 $\sigma$. Significant deviations are evident
in 3 bursts (GRB\,081215A, GRB\,090424 and GRB\,090902B) in the time-integrated
sample ($\sim$ 7%) and 5 bursts (GRB\,090323, GRB\,090424, GRB\,090820,
GRB\,090902B and GRB\,090926A) in the time-resolved sample ($\sim$ 11%).} The
advantage of the systematic, blind search analysis is that it can demonstrate
the requirement for an additional spectral component without any prior
knowledge of the nature of that extra component. Deviations are found in a
large fraction of high fluence GRBs; fainter GRBs may not have sufficient
statistics for deviations to be found using this method.


title:
Oligothiophene nano-rings as electron resonators for whispering gallery
  modes

abstract:
  Structural and electronic properties of oligothiophene nano-wires and rings
synthesized on a Au(111) surface are investigated by scanning tunneling
microscopy. The spectroscopic data of the linear and cyclic oligomers show
remarkable differences which, to a first approximation, can be accounted by
considering electronic states confinement to one-dimensional (1D) boxes having
respectively fixed and periodic boundary conditions. A more detailed analysis
shows that polythiophene must be treated as a ribbon (i.e. having an effective
width) rather than a purely 1D structure. A fascinating consequence is that the
molecular nano-rings act as whispering gallery mode resonators for electrons,
opening the way for new applications in quantum-electronics.


title: Model Reduction of Turbulent Fluid Flows Using the Supply Rate

abstract:
  A method for finding reduced-order approximations of turbulent flow models is
presented. The method preserves bounds on the production of turbulent energy in
the sense of the $\curly{L}_2$ norm of perturbations from a notional laminar
profile. This is achieved by decomposing the Navier-Stokes system into a
feedback arrangement between the linearised system and the remaining, normally
neglected, nonlinear part. The linear system is reduced using a method similar
to balanced truncation, but preserving bounds on the supply rate. The method
involves balancing two algebraic Riccati equations. The bounds are then used to
derive bounds on the turbulent energy production. An example of the application
of the procedure to flow through a long straight pipe is presented. Comparison
shows that the new method approximates the supply rate at least as well as, or
better than, canonical balanced truncation.


title:
Active Learning of Inverse Models with Intrinsically Motivated Goal
  Exploration in Robots

abstract:
  We introduce the Self-Adaptive Goal Generation - Robust Intelligent Adaptive
Curiosity (SAGG-RIAC) architecture as an intrinsi- cally motivated goal
exploration mechanism which allows active learning of inverse models in
high-dimensional redundant robots. This allows a robot to efficiently and
actively learn distributions of parameterized motor skills/policies that solve
a corresponding distribution of parameterized tasks/goals. The architecture
makes the robot sample actively novel parameterized tasks in the task space,
based on a measure of competence progress, each of which triggers low-level
goal-directed learning of the motor policy pa- rameters that allow to solve it.
For both learning and generalization, the system leverages regression
techniques which allow to infer the motor policy parameters corresponding to a
given novel parameterized task, and based on the previously learnt
correspondences between policy and task parameters. We present experiments with
high-dimensional continuous sensorimotor spaces in three different robotic
setups: 1) learning the inverse kinematics in a highly-redundant robotic arm,
2) learning omnidirectional locomotion with motor primitives in a quadruped
robot, 3) an arm learning to control a fishing rod with a flexible wire. We
show that 1) exploration in the task space can be a lot faster than exploration
in the actuator space for learning inverse models in redundant robots; 2)
selecting goals maximizing competence progress creates developmental
trajectories driving the robot to progressively focus on tasks of increasing
complexity and is statistically significantly more efficient than selecting
tasks randomly, as well as more efficient than different standard active motor
babbling methods; 3) this architecture allows the robot to actively discover
which parts of its task space it can learn to reach and which part it cannot.


title:
A nonlinear least squares method for the inverse droplet coagulation
  problem

abstract:
  If the rates, $K(x,y)$, at which particles of size $x$ coalesce with
particles of size $y$ is known, then the mean-field evolution of the
particle-size distribution of an ensemble of irreversibly coalescing particles
is described by the Smoluchowski equation. We study the corresponding inverse
problem which aims to determine the coalescence rates, $K(x,y)$ from
measurements of the particle size distribution. We assume that $K(x,y)$ is a
homogeneous function of its arguments, a case which occurs commonly in
practice. The problem of determining, $K(x,y)$, a function to two variables,
then reduces to a simpler problem of determining a function of a single
variable plus two exponents, $\mu$ and $\nu$, which characterise the scaling
properties of $K(x,y)$. The price of this simplification is that the resulting
least squares problem is nonlinear in the exponents $\mu$ and $\nu$. We
demonstrate the effectiveness of the method on a selection of coalescence
problems arising in polymer physics, cloud science and astrophysics. The
applications include examples in which the particle size distribution is
stationary owing to the presence of sources and sinks of particles and examples
in which the particle size distribution is undergoing self-similar relaxation
in time.


title: Simultaneous deformations of algebras and morphisms via derived brackets

abstract:
  We present a method to construct explicitly L-infinity algebras governing
simultaneous deformations of various kinds of algebraic structures and of their
morphisms. It is an alternative to the heavy use of the operad machinery of the
existing approaches. Our method relies on Voronov's derived bracket
construction.


title: Global structure of the pulsar force-free magnetosphere revisited

abstract:
  A new model of the pulsar force-free magnetosphere is suggested, which
includes the presence of the polar, outer and slot gaps. It is based on a new
exact solution of the pulsar equation in the form of an offset monopole and the
resultant split-offset monopole scheme.


title:
Efficient grid-based Bayesian estimation of nonlinear low-dimensional
  systems with sparse non-Gaussian PDFs

abstract:
  Bayesian estimation strategies represent the most fundamental formulation of
the state estimation problem available, and apply readily to nonlinear systems
with non-Gaussian uncertainties. The present paper introduces a novel method
for implementing grid-based Bayesian estimation which largely sidesteps the
severe computational expense that has prevented the widespread use of such
methods. The method represents the evolution of the probability density
function (PDF) in phase space, $p_{\x}(\x',t)$, discretized on a fixed
Cartesian grid over {\it all} of phase space, and consists of two main steps:
(i) Between measurement times, $p_{\x}(\x',t)$ is evolved via numerical
discretization of the Kolmogorov forward equation, using a Godunov method with
second-order corner transport upwind correction and a total variation
diminishing flux limiter; (ii) at measurement times, $p_{\x}(\x',t)$ is updated
via Bayes' theorem. Computational economy is achieved by exploiting the
localised nature of $p_{\x}(\x',t)$. An ordered list of cells with
non-negligible probability, as well as their immediate neighbours, is created
and updated, and the PDF evolution is tracked {\it only} on these active cells.
%The grid-based discretization of $p_{\x}(\x',t)$ in this approach avoids the
requirement for resampling associated with particle-based representations of
the PDF.


title:
On the use of fractional calculus for the probabilistic characterization
  of random variables

abstract:
  In this paper, the classical problem of the probabilistic characterization of
a random variable is re-examined. A random variable is usually described by the
probability density function (PDF) or by its Fourier transform, namely the
characteristic function (CF). The CF can be further expressed by a Taylor
series involving the moments of the random variable. However, in some
circumstances, the moments do not exist and the Taylor expansion of the CF is
useless. This happens for example in the case of $\alpha$--stable random
variables. Here, the problem of representing the CF or the PDF of random
variables (r.vs) is examined by introducing fractional calculus. Two very
remarkable results are obtained. Firstly, it is shown that the fractional
derivatives of the CF in zero coincide with fractional moments. This is true
also in case of CF not derivable in zero (like the CF of $\alpha$--stable
r.vs). Moreover, it is shown that the CF may be represented by a generalized
Taylor expansion involving fractional moments. The generalized Taylor series
proposed is also able to represent the PDF in a perfect dual representation to
that in terms of CF. The PDF representation in terms of fractional moments is
especially accurate in the tails and this is very important in engineering
problems, like estimating structural safety.

categories: math-ph math.MP math.ST physics.data-an stat.TH


title:
Uniqueness and nondegeneracy of positive solutions of $\Ds u+u=u^p$ in
  $\R^N$ when $s$ is close to 1

abstract:
  We consider the equation $\Ds u+u=u^p$, with $s\in(0,1)$ in the subcritical
range of $p$. We prove that if $s$ is sufficiently close to 1 the equation
possesses a unique minimizer, which is nondegenerate.


title: A simple time-consistent model for the forward density process

abstract:
  In this paper a simple model for the evolution of the forward density of the
future value of an asset is proposed. The model allows for a straightforward
initial calibration to option prices and has dynamics that are consistent with
empirical findings from option price data. The model is constructed with the
aim of being both simple and realistic, and avoid the need for frequent
re-calibration. The model prices of $n$ options and a forward contract are
expressed as time-varying functions of an $(n+1)$-dimensional Brownian motion
and it is investigated how the Brownian trajectory can be determined from the
trajectories of the price processes. An approach based on particle filtering is
presented for determining the location of the driving Brownian motion from
option prices observed in discrete time. A simulation study and an empirical
study of call options on the S&P 500 index illustrates that the model provides
a good fit to option price data.


title:
From Approximate Factorization to Root Isolation with Application to
  Cylindrical Algebraic Decomposition

abstract:
  We present an algorithm for isolating the roots of an arbitrary complex
polynomial $p$ that also works for polynomials with multiple roots provided
that the number $k$ of distinct roots is given as part of the input. It outputs
$k$ pairwise disjoint disks each containing one of the distinct roots of $p$,
and its multiplicity. The algorithm uses approximate factorization as a
subroutine.
  In addition, we apply the new root isolation algorithm to a recent algorithm
for computing the topology of a real planar algebraic curve specified as the
zero set of a bivariate integer polynomial and for isolating the real solutions
of a bivariate polynomial system. For input polynomials of degree $n$ and
bitsize $\tau$, we improve the currently best running time from
$\tO(n^{9}\tau+n^{8}\tau^{2})$ (deterministic) to $\tO(n^{6}+n^{5}\tau)$
(randomized) for topology computation and from $\tO(n^{8}+n^{7}\tau)$
(deterministic) to $\tO(n^{6}+n^{5}\tau)$ (randomized) for solving bivariate
systems.


title: Mirror symmetry for orbifold Hurwitz numbers

abstract:
  We study mirror symmetry for orbifold Hurwitz numbers. We show that the
Laplace transform of orbifold Hurwitz numbers satisfy a differential recursion,
which is then proved to be equivalent to the integral recursion of Eynard and
Orantin with spectral curve given by the r-Lambert curve. We argue that the
r-Lambert curve also arises in the infinite framing limit of orbifold
Gromov-Witten theory of [C3/(Z/rZ)]. Finally, we prove that the mirror model to
orbifold Hurwitz numbers admits a quantum curve.


title: Density Matrix Topological Insulators

abstract:
  Thermal noise can destroy topological insulators (TI). However we demonstrate
how TIs can be made stable in dissipative systems. To that aim, we introduce
the notion of band Liouvillian as the dissipative counterpart of band
Hamiltonian, and show a method to evaluate the topological order of its steady
state. This is based on a generalization of the Chern number valid for general
mixed states (referred to as density matrix Chern value), which witnesses
topological order in a system coupled to external noise. Additionally, we study
its relation with the electrical conductivity at finite temperature, which is
not a topological property. Nonetheless, the density matrix Chern value
represents the part of the conductivity which is topological due to the
presence of quantum mixed edge states at finite temperature. To make our
formalism concrete, we apply these concepts to the two-dimensional Haldane
model in the presence of thermal dissipation, but our results hold for
arbitrary dimensions and density matrices.


title: Functional data analysis in an operator-based mixed-model framework

abstract:
  Functional data analysis in a mixed-effects model framework is done using
operator calculus. In this approach the functional parameters are treated as
serially correlated effects giving an alternative to the penalized likelihood
approach, where the functional parameters are treated as fixed effects.
Operator approximations for the necessary matrix computations are proposed, and
semi-explicit and numerically stable formulae of linear computational
complexity are derived for likelihood analysis. The operator approach renders
the usage of a functional basis unnecessary and clarifies the role of the
boundary conditions.


title: Vector Addition System Reversible Reachability Problem

abstract:
  The reachability problem for vector addition systems is a central problem of
net theory. This problem is known to be decidable but the complexity is still
unknown. Whereas the problem is EXPSPACE-hard, no elementary upper bounds
complexity are known. In this paper we consider the reversible reachability
problem. This problem consists to decide if two configurations are reachable
one from each other, or equivalently if they are in the same strongly connected
component of the reachability graph. We show that this problem is
EXPSPACE-complete. As an application of the introduced materials we
characterize the reversibility domains of a vector addition system.


title: On functional calculus properties of Ritt operators

abstract:
  We compare various functional calculus properties of Ritt operators. We show
the existence of a Ritt operator T : X --> X on some Banach space X with the
following property: T has a bounded $\H^\infty$ functional calculus with
respect to the unit disc $\D$ (that is, T is polynomially bounded) but T does
not have any bounded $\H^\infty$ functional calculus with respect to a Stolz
domain of $\D$ with vertex at 1. Also we show that for an R-Ritt operator, the
unconditional Ritt condition of Kalton-Portal is equivalent to the existence of
a bounded $\H^\infty$ functional calculus with respect to such a Stolz domain.


title:
The entrepreneurial role of the University: a link analysis of York
  Science Park

abstract:
  This study introduces a structured analysis of science parks as arenas
designed to stimulate institutional collaboration and the commercialization of
academic knowledge and technology, and the promotion of social welfare. A
framework for key actors and their potential behaviour in this context is
introduced based on the Triple Helix (TH) model and related literature. A link
analysis was conducted to build an inter-linking network that may map the
infrastructure support network through the online interactions of the
organisations involved in York Science Park. A comparison between the framework
and the diagram shows that the framework can be used to identify most of the
actors and assess their interconnections. The web patterns found correspond to
previous evaluations based on traditional indicators and suggest that the
network, which is developed to foster and support innovation, arises from the
functional cooperation between the University of York and regional authorities,
which both serve as the major driving forces in the trilateral linkages and the
development of an innovation infrastructure.


title: Proof of Sun's conjecture on the divisibility of certain binomial sums

abstract:
  In this paper, we prove the following result conjectured by Z.-W. Sun: $$
(2n-1){3n\choose n}| \sum_{k=0}^{n}{6k\choose 3k}{3k\choose k}{6(n-k)\choose
3(n-k)}{3(n-k)\choose n-k}. $$ by showing that the left-hand side divides each
summand on the right-hand side.


title: The monodromy conjecture for plane meromorphic germs

abstract:
  A notion of Milnor fibration for meromorphic functions and the corresponding
concepts of monodromy and monodromy zeta function have been introduced in
[GZLM1]. In this article we define the topological zeta function for
meromorphic germs and we study its poles in the plane case. We show that the
poles do not behave as in the holomorphic case but still do satisfy a
generalization of the monodromy conjecture.


title:
Some Comments on Ghosts and Unitarity: The Pais-Uhlenbeck Oscillator
  Revisited

abstract:
  We give a simple discussion of ghosts, unitarity violation, negative norm
states and quantum vs classical behavior in the simplest model with four
derivative action - the Pais-Uhlenbeck oscillator. We also point out that the
normalizable "vacuum state" (in the sense defined below) of this model can be
understood as spontaneous breaking of the emergent conformal symmetry. We
provide an example of an interacting system that couples the "particle" and
"ghost" degrees of freedom and nevertheless remains unitary on both classical
and quantum level.


title: CP Violation in Hadronic B Decays at CDF

abstract:
  I report recent measurements in b-hadron decays reconstructed in the full
data set of \sqrt{s} = 1.96 TeV proton-antiproton collisions collected by the
CDF experiment at the Tevatron. These include the final CDF results on:
measurements of CP asymmetries in two-body charmless decays of the Bd, Bs, and
\Lambda^0_b hadrons; bounds on the Bs mixing phase and on the decay width
difference of Bs mass eigenstates; and updated measurements of branching ratios
of Bs->Jpsi Phi and Bs->Ds(*)Ds(*) decays. All measurements are among the most
precise from a single experiment and in agreement with the standard model
predictions.


title:
On the optimal allocation of assets in investment portfolio with
  application of modern portfolio and nonlinear dynamic chaos theories in
  investment, commercial and central banks

abstract:
  The investment economy is a main characteristic of prosperous society. The
investment portfolio management is a main financial problem, which has to be
solved by the investment, commercial and central banks with the application of
modern portfolio theory in the investment economy. We use the learning
analytics together with the integrative creative imperative intelligent
conceptual co-lateral adaptive thinking with the purpose to advance our
scientific knowledge on the diversified investment portfolio management in the
nonlinear dynamic financial system. We apply the econophysics principles and
the econometrics methods with the aim to find the solution to the problem of
the optimal allocation of assets in the investment portfolio, using the
advanced risk management techniques with the efficient frontier modeling in
agreement with the modern portfolio theory and using the stability management
techniques with the dynamic regimes modeling on the bifurcation diagram in
agreement with the dynamic chaos theory. We show that the bifurcation diagram,
created with the use of the logistic function in Matlab, can provide some
valuable information on the stability of combining risky investments in the
investment portfolio, solving the problem of optimization of assets allocation
in the investment portfolio. We propose the Ledenyov investment portfolio
theorem, based on the Lyapunov stability criteria, with the aim to create the
optimized investment portfolio with the uncorrelated diversified assets, which
can deliver the increased expected returns to the institutional and private
investors in the nonlinear dynamic financial system in the frames of investment
economy.


title:
Josephson-like behavior in YBa$_2$Cu$_3$O$_{7-\delta}$ nano-bridges
  carrying the depairing current

abstract:
  We have investigated the zero-field critical supercurrent of
YBa$_2$Cu$_3$O$_{7-\delta}$ bridges patterned from 50 nm thick films as a
function of bridge width, ranging from 2 $\mu$m to 50 nm. The critical current
density monotonically increases for decreasing bridge width even for widths
smaller than the Pearl length. This behavior is accounted for by considering
current crowding effects at the junction between the bridge and the wider
electrodes. Comparison to numerical calculations of the current distributions
in our bridge geometries of various widths yields a (local) critical current
density at 4.2 K of $1.3\times 10^8$ A/cm$^2$, the Ginzburg Landau depairing
current density. The observation of up to 160 Shapiro-like steps in the current
voltage characteristics under microwave irradiation substantiates the pristine
character of our nano bridges with cross sections as small as $50\times 50$
nm$^2$.


title:
Visualizing multiphase flow and trapped fluid configurations in a model
  three-dimensional porous medium

abstract:
  We report an approach to fully visualize the flow of two immiscible fluids
through a model three-dimensional (3D) porous medium at pore-scale resolution.
Using confocal microscopy, we directly image the drainage of the medium by the
non-wetting oil and subsequent imbibition by the wetting fluid. During
imbibition, the wetting fluid pinches off threads of oil in the narrow crevices
of the medium, forming disconnected oil ganglia. Some of these ganglia remain
trapped within the medium. By resolving the full 3D structure of the trapped
ganglia, we show that the typical ganglion size, and the total amount of
residual oil, decreases as the capillary number Ca increases; this behavior
reflects the competition between the viscous pressure in the wetting fluid and
the capillary pressure required to force oil through the pores of the medium.
This work thus shows how pore-scale fluid dynamics influence the trapped fluid
configurations in multiphase flow through 3D porous media.

categories: physics.flu-dyn cond-mat.dis-nn cond-mat.mtrl-sci cond-mat.soft cond-mat.stat-mech


title: Delimiting Maximal Kissing Configurations in Four Dimensions

abstract:
  How many unit $n-$dimensional spheres can simultaneously touch or kiss a
central $n-$dimensional unit sphere? Beyond mathematics this question has
implications for fields such as cryptography and the structure of biologic and
chemical macromolecules. The kissing number is only known for dimensions 1-4, 8
and 24 (2, 6, 12, 24, 240, 19650, respectively) and only particularly obvious
for dimensions one and two. Indeed, in four dimensions it is not even known if
Platonic polytope unique to that dimension known as the 24-cell is the unique
kissing configuration. We have not been able to prove that the 24-cell is
unique, but, using a physical approach utilizing the hopf map from four to
three dimensions, we for the first time delimit the possible other
configurations which could be kissing in four dimensions.


title:
Role of critical spin fluctuations in ultrafast demagnetization of
  transition-metal rare-earth alloys

abstract:
  Ultrafast magnetization dynamics induced by femtosecond laser pulses have
been measured in ferrimagnetic Co0.8Gd0.2, Co.74Tb.26 and Co.86Tb.14 alloys.
Using element sensitivity of X-ray magnetic circular dichroism at the Co L3, Tb
M5 and Gd M5 edges we evidence that the demagnetization dynamics is element
dependent. We show that a thermalization time as fast as 280 fs is observed for
the rare-earth in the alloy, when the laser excited state temperature is below
the compensation temperature. It is limited to 500 fs when the laser excited
state temperature is below the Curie temperature (Tc). We propose critical spin
fluctuations in the vicinity of TC as the mechanism which reduces the
demagnetization rates of the 4f electrons in transition-metal rare-earth alloys
whereas at any different temperature the limited demagnetization rates could be
avoided.


title:
On the spectrum and eigenfunctions of the operator $(Vf)(x) =
  \int_0^{x^\alpha} f(t) dt$

abstract:
  We find spectrum and eigenfunctions of the operator $(Vf)(x) =
\int_0^{x^\alpha} f(t) dt$ in $L_2[0,1]$


title:
Explicit matrix inverses for lower triangular matrices with entries
  involving Jacobi polynomials

abstract:
  For a two-parameter family of lower triangular matrices with entries
involving Jacobi polynomials an explicit inverse is given, with entries
involving a sum of two Jacobi polynomials. The formula simplifies in the
Gegenbauer case and then one choice of the parameter solves an open problem in
a recent paper by Koelink, van Pruijssen & Roman. The two-parameter family is
closely related to two two-parameter groups of lower triangular matrices, of
which we also give the explicit generators. Another family of pairs of mutually
inverse lower triangular matrices with entries involving Jacobi polynomials,
unrelated to the family just mentioned, was given by J. Koekoek & R. Koekoek
(1999). We show that this last family is a limit case of a pair of connection
relations between Askey-Wilson polynomials having one of their four parameter
in common.


title: Notes on q-analogues of a binomial congruence of Glaisher

abstract:
  Andrews once gave $q$-analogues of a binomial congruence of Glaisher, and he
suggested perfect $q$-analogues. In this note we give ones meeting the demand
of Andrews.


title:
On the spectrum of the operator which is a composition of integration
  and substitution

abstract:
  We study the spectrum of the Volterra composition operator in the space
$L_2[0,1]$


title:
Consistent cosmology with Higgs thermal inflation in a minimal extension
  of the MSSM

abstract:
  We consider a class of models in which minimal gauged F-term hybrid inflation
is coupled renormalisably to the minimal supersymmetric standard model (MSSM),
with no extra ingredients; we call this class the "minimal hybrid inflationary
supersymmetric standard model" (MHISSM). The singlet inflaton supplies the
Higgs mu-term, and allows an exit from inflation to a vacuum characterised by
large Higgs vevs. The true ground state is reached after an period of thermal
inflation along the Higgs flat direction. The scalar spectral index is reduced
from the standard F-term value, to approximately 0.976 in the case where the
inflaton potential is dominated by the 1-loop corrections. The reheat
temperature following thermal inflation is about 10^9 GeV, solving the
gravitino overclosure problem. A Higgs condensate reduces the cosmic string
mass per unit length, rendering it compatible with the Cosmic Microwave
Background constraints without tuning the inflaton coupling. With the minimal
U(1)' gauge symmetry in the inflaton sector, where one of the waterfall fields
generates a right-handed neutrino mass, we investigate the Higgs thermal
inflation scenario in three popular supersymmetry-breaking schemes: AMSB, GMSB
and the CMSSM, focusing on the constraints on the gravitino mass.


title: Can $f(T)$ gravity theories mimic $\Lambda$CDM cosmic history

abstract:
  Recently the teleparallel Lagrangian density described by the torsion scalar
T has been extended to a function of T. The $f(T)$ modified teleparallel
gravity has been proposed as the natural gravitational alternative for dark
energy to explain the late time acceleration of the universe. In order to
reconstruct the function $f(T)$ by demanding a background $\Lambda$CDM
cosmology we assume that, (i) the background cosmic history provided by the
flat $\Lambda$CDM (the radiation ere with $\omega_{eff}=1/3$, matter and de
Sitter eras with $\omega_{eff}=0$ and $\omega_{eff}=-1$, respectively) (ii) the
radiation dominate in the radiation era with $\Omega_{0r}=1$ and the matter
dominate during the matter phases when $\Omega_{0m}=1$. We find the
cosmological dynamical system which can obey the $\Lambda$CDM cosmic history.
In each era, we find a critical lines that, the radiation dominated and the
matter dominated are one points of them in the radiation and matter phases,
respectively. Also, we drive the cosmologically viability condition for these
models. We investigate the stability condition with respect to the homogeneous
scalar perturbations in each era and we obtain the stability conditions for the
fixed points in each eras. Finally, we reconstruct the function $f(T)$ which
mimics cosmic expansion history.


title: Annihilation of singlet fermionic dark matter into two photons

abstract:
  We consider an extension of the standard model in which a singlet fermionic
particle, to serve as cold dark matter, and a singlet Higgs are added. We
perform a reanalysis on the free parameters. In particular, demanding a correct
relic abundance of dark matter, we derive and plot the coupling of the singlet
fermion with the singlet Higgs, $g_s$, versus the dark matter mass. We
analytically compute the pair annihilation cross section of singlet fermionic
dark matter into two photons. The thermally averaged of this cross section is
calculated for wide range of energies and plotted versus dark matter mass using
$g_s$ consistent with the relic abundance condition. We also compare our
results with the Fermi-Lat observations.


title: An Introduction to the Quantum Backflow Effect

abstract:
  We present an introduction to the backflow effect in quantum mechanics -- the
phenomenon in which a state consisting entirely of positive momenta may have
negative current and the probability flows in the opposite direction to the
momentum. We show that the effect is present even for simple states consisting
of superpositions of gaussian wave packets, although the size of the effect is
small. Inspired by the numerical results of Penz et al, we present a wave
function whose current at any time may be computed analytically and which has
periods of significant backflow, with a backwards flux equal to about 70
percent of the maximum possible backflow, a dimensionless number $c_{bm}
\approx 0.04 $, discovered by Bracken and Melloy. This number has the unusual
property of being independent of $\hbar$ (and also of all other parameters of
the model), despite corresponding to a quantum-mechanical effect, and we shed
some light on this surprising property by considering the classical limit of
backflow. We conclude by discussing a specific measurement model in which
backflow may be identified in certain measurable probabilities.


title: Analysis of Free Boundaries for Convertible Bonds, with a call feature

abstract:
  Convertible bonds give rise to the so-called free boundary; i.e., an unknown
boundary between continuation and conversion regions of the bond. The
characteristic feature of such a bond, with an extra call feature, is that the
free boundary may reach all the way to the fixed boundary. Our intention in
this paper is to study the behavior of the free boundary in the vicinity of a
touching point with the fixed boundary. Along the lines of our analysis we will
also produce some results on regularity of solutions (value of the bond) up to
the fixed boundary. Our methods are robust and of general nature, and can be
applied to fully nonlinear equations. In particular, we shall obtain uniform
results for the regularity of both solutions and their free boundaries.


title:
A recursive approach to determine correlation functions in multi-baryon
  systems

abstract:
  We propose a recursive algorithm for the calculation of multi-baryon
correlation functions that combines the advantages of a recursive approach with
those of the recently proposed unified contraction algorithm. The independent
components of the correlators are built recursively by adding the baryons one
after the other in a given order. The list of nonzero independent components is
also constructed in a recursive manner, significantly reducing the resources
required for this step. We computed the number of operations required to
calculate the correlators up to Be^8, and observed a significant speedup
compared to other techniques. For the calculation of He^4 and Be^8 correlation
functions in the fully relativistic case O(10^8) operations are required,
whereas for non-relativistic operators this number can be reduced to e.g.
O(10^4) in the case of He^4.


title:
IGR J19308+0530: Roche lobe overflow on to a compact object from a donor
  1.8 times as massive

abstract:
  We present phase-resolved spectroscopy and photometry of the optical
counterpart to the X-ray binary IGR J19308+0530. Ellipsoidal modulations in the
light curve show that the F-type companion star in the system is Roche lobe
filling. The optical spectra are dominated by absorption features from the
donor star, with ~10-20 per cent disc contribution to the optical continuum. We
measure an orbital period of 14.662+-0.001 h, a radial velocity semiamplitude
for the companion star of K2 = 91.4+-1.4 kms-1 and a rotational broadening of
vsini = 108.9+-0.6 kms-1. From K2 and vsini, given that the donor star is
filling its Roche lobe, we derive a mass ratio of q = M2/M1=1.78+-0.04, which
is typically considered to be too large for stable Roche lobe overflow. Our
observations support an inclination of ~50 degrees. The accretor in IGR
J19308+0530 is most likely a white dwarf, although a neutron star cannot
entirely be excluded.


title: Deformation of C*-algebras by cocycles on locally compact quantum groups

abstract:
  Given a C*-algebra A with a left action of a locally compact quantum group G
on it and a unitary 2-cocycle Omega on \hat G, we define a deformation A_Omega
of A. The construction behaves well under certain additional technical
assumptions on Omega, the most important of which is regularity, meaning that
C_0(G)_Omega\rtimes G is isomorphic to the algebra of compact operators on some
Hilbert space. In particular, then A_\Omega is stably isomorphic to the
iterated twisted crossed product \hat G^{op}\ltimes_\Omega G\ltimes A. Also, in
good situations, the C*-algebra A_\Omega carries a left action of the deformed
quantum group G_\Omega and we have an isomorphism G_\Omega\ltimes A_\Omega\cong
G\ltimes A. When G is a genuine locally compact group, we show that the action
of G on C_0(G)_Omega=C*_r(\hat G;Omega) is always integrable. Stronger
assumptions of properness and saturation of the action imply regularity. As an
example, we make a preliminary analysis of the cocycles on the duals of some
solvable Lie groups recently constructed by Bieliavsky et al., and discuss the
relation of our construction to that of Bieliavsky and Gayral.


title: Stellar Populations in the Outer Halo of the Massive Elliptical M49

abstract:
  We use deep surface photometry of the giant elliptical M49 (NGC 4472),
obtained as part of our survey for diffuse light in the Virgo Cluster, to study
the stellar populations in its outer halo. Our data trace M49's stellar halo
out to ~ 100 kpc (7 Re), where we find that the shallow color gradient seen in
the inner regions becomes dramatically steeper. The outer regions of the galaxy
are quite blue (B-V ~ 0.7); if this is purely a metallicity effect, it argues
for extremely metal poor stellar populations with [Fe/H] < -1. We also find
that the extended accretion shells around M49 are distinctly redder than the
galaxy's surrounding halo, suggesting that we are likely witnessing the buildup
of both the stellar mass and metallicity in M49's outer halo due to late time
accretion. While such growth of galaxy halos is predicted by models of
hierarchical accretion, this growth is thought to be driven by more massive
accretion events which have correspondingly higher mean metallicity than
inferred for M49's halo. Thus the extremely metal-poor nature of M49's extended
halo provides some tension against current models for elliptical galaxy
formation.


title:
Analytical approach for type-II semiconductor spherical core-shell
  quantum dots heterostructures with wide band gaps

abstract:
  A one-band model within the effective mass approximation is adopted to
characterize the energy structure and oscillator strength of type-II
semiconductor spherical core-shell quantum dots. The heteroepitaxial strain of
the core-shell heterostructure is modeled by the elastic continuum approach.
The model is applied to ZnTe/ZnSe core-shell, a wide band gap type-II
heterostructure. The simulated absorption spectra are in fair agreement with
available experimental results.


title: Alpha-admissibility for Ritt operators

abstract:
  Let T : X --> X$ be a power bounded operator on Banach space. An operator C :
X --> Y$ is called admissible for T if it satisfies an estimate
$\sum_k\norm{CT^k(x)}^2\,\leq M^2\norm{x}^2$. Following Harper and Wynn, we
study the validity of a certain Weiss conjecture in this discrete setting. We
show that when X is reflexive and T is a Ritt operator satisfying a appropriate
square function estimate, C is admissible for T if and only if it satisfies a
uniform estimate $(1-| \omega|^2)^{1/2}\norm{C(I-\omega T)^{-1}}\,\leq K$ for
$\omega\in \Cdb$, $|\omega|<1$. We extend this result to the more general
setting of alpha-admissibility. Then we investigate a natural variant of
admissibility involving R-boundedness and provide examples to which our general
results apply.


title: Sampling from a polytope and hard-disk Monte Carlo

abstract:
  The hard-disk problem, the statics and the dynamics of equal two-dimensional
hard spheres in a periodic box, has had a profound influence on statistical and
computational physics. Markov-chain Monte Carlo and molecular dynamics were
first discussed for this model. Here we reformulate hard-disk Monte Carlo
algorithms in terms of another classic problem, namely the sampling from a
polytope. Local Markov-chain Monte Carlo, as proposed by Metropolis et al. in
1953, appears as a sequence of random walks in high-dimensional polytopes,
while the moves of the more powerful event-chain algorithm correspond to
molecular dynamics evolution. We determine the convergence properties of Monte
Carlo methods in a special invariant polytope associated with hard-disk
configurations, and the implications for convergence of hard-disk sampling.
Finally, we discuss parallelization strategies for event-chain Monte Carlo and
present results for a multicore implementation.


title: A brief review of antimatter production

abstract:
  In this article, we present a brief review of the discoveries of kinds of
antimatter particles, including positron, antiproton, antideuteron and
antihelium-3. Special emphasis is put on the discovery of the antihypertriton
and antihelium-4 nucleus which were reported by the RHIC-STAR experiment very
recently. In addition, brief discussions about the effort to search for
antinuclei in cosmic rays and study of the longtime confinement of the simplest
antimatter atom, antihydrogen are also given. Moreover, the production
mechanism of anti-light nuclei is introduced.


title:
Dualizing complexes of seminormal affine semigroup rings and toric face
  rings

abstract:
  We characterize the seminormality of an affine semigroup ring in terms of the
dualizing complex, and the normality of a Cohen-Macaulay semigroup ring by the
"shape" of the canonical module. We also characterize the seminormality of a
toric face ring in terms of the dualizing complex. A toric face ring is a
simultaneous generalization of Stanley-Reisner rings and affine semigroups.


title:
Monte Carlo configuration interaction applied to multipole moments,
  ionisation energies and electron affinities

abstract:
  The method of Monte Carlo configuration interaction (MCCI) [1,2] is applied
to the calculation of multipole moments. We look at the ground and excited
state dipole moments in carbon monoxide. We then consider the dipole of NO, the
quadrupole of the nitrogen molecule and of BH. An octupole of methane is also
calculated. We consider experimental geometries and also stretched bonds. We
show that these non-variational quantities may be found to relatively good
accuracy when compared with FCI results, yet using only a small fraction of the
full configuration interaction space. MCCI results in the aug-cc-pVDZ basis are
seen to generally have reasonably good agreement with experiment. We also
investigate the performance of MCCI when applied to ionisation energies and
electron affinities of atoms in an aug-cc-pVQZ basis. We compare the MCCI
results with full configuration-interaction quantum Monte Carlo [3,4] and
`exact' non-relativistic results [3,4]. We show that MCCI could be a useful
alternative for the calculation of atomic ionisation energies however electron
affinities appear much more challenging for MCCI. Due to the small magnitude of
the electron affinities their percentage errors can be high, but with regards
to absolute errors MCCI performs similarly for ionisation energies and electron
affinities.


title: Beyond Confinement

abstract: A digest of my closing remarks at ConfX.


title:
Electron momentum distributions and photoelectron spectra of atoms
  driven by intense spatially inhomogeneous field

abstract:
  We use three dimensional time-dependent Schr\"odinger equation (3D--TDSE) to
calculate angular electron momentum distributions and photoelectron spectra of
atoms driven by spatially inhomogeneous fields. An example for such
inhomogeneous fields is the locally enhanced field induced by resonant
plasmons, appearing at surfaces of metallic nanoparticles, nanotips and gold
bow-tie shape nanostructures. Our studies show that the inhomogeneity of the
laser electric field plays an important role in the above threshold ionization
process in the tunneling regime, causing significant modifications to the
electron momentum distributions and photoelectron spectra, while its effects in
the multiphoton regime appear to be negligible. Indeed, through tunneling ATI
process, one can obtain higher energy electrons as well as high degree of
asymmetry in the momentum space map. In this study we consider near infrared
laser fields with intensities in the mid-$10^{14}$ W/cm$^{2}$ range and we use
linear approximation to describe their spatial dependence. We show that in this
case it is possible to drive electrons with energies in the near-keV regime.
Furthermore, we study how the carrier envelope phase influences the emission of
ATI photoelectrons for few-cycle pulses. Our quantum mechanical calculations
are fully supported by their classical counterparts.


title: Roton confinement in trapped dipolar Bose-Einstein condensates

abstract:
  Roton excitations constitute a key feature of dipolar gases, connecting these
gases with superfluid helium. We show that the density dependence of the roton
minimum results in a spatial roton confinement, particularly relevant in
pancake dipolar condensates with large aspect ratios. We show that roton
confinement plays a crucial role in the dynamics after roton instability, and
that arresting the instability may create a trapped roton gas revealed by
confined density modulations. We discuss the local susceptibility against
density perturbations, which we illustrate for the case of vortices. Roton
confinement is expected to play a key role in experiments.


title: Long Gamma-Ray Burst Host Galaxies and their Environments

abstract:
  In this book-chapter we first briefly discuss some basic observational issues
related to what a GRB host galaxy is (whether they are operationally well
defined as a class) and sample completeness. We then describe some of the early
studies of GRB hosts starting with statistical studies of upper limits done
prior to the first detections, the first host detection after the BeppoSAX
breakthrough and leading up to the current Swift era. Finally, we discuss the
status of efforts to construct a more complete sample of GRBs based on Swift
and end with an outlook. We only consider the host galaxies of long-duration
GRBs.


title:
Analyzing the Performance of LRU Caches under Non-Stationary Traffic
  Patterns

abstract:
  This work presents, to the best of our knowledge of the literature, the first
analytic model to address the performance of an LRU (Least Recently Used)
implementing cache under non-stationary traffic conditions, i.e., when the
popularity of content evolves with time. We validate the accuracy of the model
using Monte Carlo simulations. We show that the model is capable of accurately
estimating the cache hit probability, when the popularity of content is
non-stationary.
  We find that there exists a dependency between the performance of an LRU
implementing cache and i) the lifetime of content in a system, ii) the volume
of requests associated with it, iii) the distribution of content request
volumes and iv) the shape of the popularity profile over time.


title: Computational Aspects of the Calculus of Structure

abstract:
  Logic is the science of correct inferences and a logical system is a tool to
prove assertions in a certain logic in a correct way. There are many logical
systems, and many ways of formalizing them, e.g., using natural deduction or
sequent calculus. Calculus of structures (CoS) is a new formalism proposed by
Alessio Guglielmi in 2004 that generalizes sequent calculus in the sense that
inference rules can be applied at any depth inside a formula, rather than only
to the main connective. With this feature, proofs in CoS are shorter than in
any other formalism supporting analytical proofs. Although it is great to have
the freedom and expressiveness of CoS, under the point of view of proof search
more freedom means a larger search space. And that should be restricted when
looking for complete automation of deductive systems. Some efforts were made to
reduce this non-determinism, but they are all basically operational approaches,
and no solid theoretical result regarding the computational behaviour of CoS
has been achieved so far. The main focus of this thesis is to discuss ways to
propose a proof search strategy for CoS suitable to implementation. This
strategy should be theoretical instead of purely operational. We introduce the
concept of incoherence number of substructures inside structures and we use
this concept to achieve our main result: there is an algorithm that, according
to our conjecture, corresponds to a proof search strategy to every provable
structure in the subsystem of FBV (the multiplicative linear logic MLL plus the
rule mix) containing only pairwise distinct atoms. Our algorithm is implemented
and we believe our strategy is a good starting point to exploit the
computational aspects of CoS in more general systems, like BV itself.


title:
On the minimum of asymptotic translation lengths of point-pushing
  pseudo-Anosov maps on one punctured Riemann surfaces

abstract:
  We show that the minimum of asymptotic translation lengths of all
point-pushing pseudo-Anosov maps on any one punctured Riemann surface is one.


title:
Elliptic Ding-Iohara Algebra and the Free Field Realization of the
  Elliptic Macdonald Operator

abstract:
  The Ding-Iohara algebra is a quantum algebra arising from the free field
realization of the Macdonald operator. Starting from the elliptic kernel
function introduced by Komori, Noumi and Shiraishi, we can define an elliptic
analog of the Ding-Iohara algebra. The free field realization of the elliptic
Macdonald operator is also constructed.


title:
Advanced Interacting Sequential Monte Carlo Sampling for Inverse
  Scattering

abstract:
  The following electromagnetism (EM) inverse problem is addressed. It consists
in estimating local radioelectric properties of materials recovering an object
from global EM scattering measurements, at various incidences and wave
frequencies. This large scale ill-posed inverse problem is explored by an
intensive exploitation of an efficient 2D Maxwell solver, distributed on high
performance computing machines. Applied to a large training data set, a
statistical analysis reduces the problem to a simpler probabilistic metamodel,
on which Bayesian inference can be performed. Considering the radioelectric
properties as a hidden dynamic stochastic process, that evolves in function of
the frequency, it is shown how advanced Markov Chain Monte Carlo methods,
called Sequential Monte Carlo (SMC) or interacting particles, can take benefit
of the structure and provide local EM property estimates.


title:
The equivalence of viscosity and distributional subsolutions for convex
  subequations - a strong Bellman principle

abstract:
  There are two useful ways to extend nonlinear partial differential
inequalities of second order: one uses viscosity theory and the other uses the
theory of distributions. This paper considers the convex situation where both
extensions can be applied. The main result is that under a natural
"second-order completeness" hypothesis, the two sets of extensions are
isomorphic, in a sense that is made precise.


title:
The Closed String Tachyon and its relationship with the evolution of the
  Universe

abstract:
  We present a cosmological landscape where the classical closed string tachyon
field plays an important role in the framework of a critical bosonic
compactification. Our cosmological solutions for a universe with constant
curvature describes an finite inflationary stage which expands till a maximum
value before undergoes a big crunch as the tachyon reaches the minimum of its
potential.


title: Solutions to Detect and Analyze Online Radicalization : A Survey

abstract:
  Online Radicalization (also called Cyber-Terrorism or Extremism or
Cyber-Racism or Cyber- Hate) is widespread and has become a major and growing
concern to the society, governments and law enforcement agencies around the
world. Research shows that various platforms on the Internet (low barrier to
publish content, allows anonymity, provides exposure to millions of users and a
potential of a very quick and widespread diffusion of message) such as YouTube
(a popular video sharing website), Twitter (an online micro-blogging service),
Facebook (a popular social networking website), online discussion forums and
blogosphere are being misused for malicious intent. Such platforms are being
used to form hate groups, racist communities, spread extremist agenda, incite
anger or violence, promote radicalization, recruit members and create virtual
organi- zations and communities. Automatic detection of online radicalization
is a technically challenging problem because of the vast amount of the data,
unstructured and noisy user-generated content, dynamically changing content and
adversary behavior. There are several solutions proposed in the literature
aiming to combat and counter cyber-hate and cyber-extremism. In this survey, we
review solutions to detect and analyze online radicalization. We review 40
papers published at 12 venues from June 2003 to November 2011. We present a
novel classification scheme to classify these papers. We analyze these
techniques, perform trend analysis, discuss limitations of existing techniques
and find out research gaps.


title: Dirichlet draws are sparse with high probability

abstract:
  This note provides an elementary proof of the folklore fact that draws from a
Dirichlet distribution (with parameters less than 1) are typically sparse (most
coordinates are small).


title:
Measurements of vacuum magnetic birefringence using permanent dipole
  magnets: the PVLAS experiment

abstract:
  The PVLAS collaboration is presently assembling a new apparatus (at the INFN
section of Ferrara, Italy) to detect vacuum magnetic birefringence (VMB). VMB
is related to the structure of the QED vacuum and is predicted by the
Euler-Heisenberg-Weisskopf effective Lagrangian. It can be detected by
measuring the ellipticity acquired by a linearly polarised light beam
propagating through a strong magnetic field. Using the very same optical
technique it is also possible to search for hypothetical low-mass particles
interacting with two photons, such as axion-like (ALP) or millicharged
particles (MCP). Here we report results of a scaled-down test setup and
describe the new PVLAS apparatus. This latter one is in construction and is
based on a high-sensitivity ellipsometer with a high-finesse Fabry-Perot cavity
($>4\times 10^5$) and two 0.8 m long 2.5 T rotating permanent dipole magnets.
Measurements with the test setup have improved by a factor 2 the previous upper
bound on the parameter $A_e$, which determines the strength of the nonlinear
terms in the QED Lagrangian: $A_e^{\rm (PVLAS)} < 3.3 \times 10^{-21}$ T$^{-2}$
95% c.l. Furthermore, new laboratory limits have been put on the inverse
coupling constant of ALPs to two photons and confirmation of previous limits on
the fractional charge of millicharged particles is given.


title: Errata to 'A cylindrical reformulation of Heegaard Floer homology'

abstract:
  This note corrects one serious mistake and several smaller mistakes from
arXiv:math/0502404. The main results of that paper are unchanged.


title:
Massless scalar field in de Sitter spacetime: unitary quantum time
  evolution

abstract:
  We prove that, under the standard conformal scaling, a massless field in de
Sitter spacetime admits an O(4)-invariant Fock quantization such that time
evolution is unitarily implemented. This result disproves previous claims in
the literature. We discuss the relationship between this quantization with
unitary dynamics and the family of O(4)-invariant Hadamard states given by
Allen and Folacci, as well as with the Bunch-Davies vacuum.


title: Hadron to Vector Mesons - Photons and the Electromagnetic Form Factors

abstract:
  In Ultra Relativistic Heavy-Ion Collisions (URHIC's) the light vector mesons
play a crucial role in the description of hadronic interactions in a
non-pertrubative QCD region. In this region efective hadron models use
composite hadrons and mesons as field carriers instead of quarks and gluons.
This theoretical review article tries to give a short way of understanding the
underlying theory that we have for the conversion of vector mesons into photons
together with the so-called Vector Dominance Model (VDM) and the
electromagnetic form factors.


title:
Irradiation of an Accretion Disc by a Jet: General Properties and
  Implications for Spin Measurements of Black Holes

abstract:
  X-ray irradiation of the accretion disc leads to strong reflection features,
which are then broadened and distorted by relativistic effects. We present a
detailed, general relativistic approach to model this irradiation for different
geometries of the primary X-ray source. These geometries include the standard
point source on the rotational axis as well as more jet-like sources, which are
radially elongated and accelerating. Incorporating this code in the relline
model for relativistic line emission, the line shape for any configuration can
be predicted. We study how different irradiation geometries affect the
determination of the spin of the black hole. Broad emission lines are produced
only for compact irradiating sources situated close to the black hole. This is
the only case where the black hole spin can be unambiguously determined. In all
other cases the line shape is narrower, which could either be explained by a
low spin or an elongated source. We conclude that for all those cases and
independent of the quality of the data, no unique solution for the spin exists
and therefore only a lower limit of the spin value can be given.


title: Anderson's Orthogonality Catastrophe for One-dimensional Systems

abstract:
  We derive rigorously the leading asymptotics of the so-called Anderson
integral in the thermodynamic limit for one-dimensional, non-relativistic,
spin-less Fermi systems. The coefficient, $\gamma$, of the leading term is
computed in terms of the S-matrix. This implies a lower and an upper bound on
the exponent in Anderson's orthogonality catastrophe, $\tilde
CN^{-\tilde\gamma}\leq \mathcal{D}_N\leq CN^{-\gamma}$ pertaining to the
overlap, $\mathcal{D}_N$, of ground states of non-interacting fermions.


title:
On the developments of Sklyanin's quantum separation of variables for
  integrable quantum field theories

abstract:
  We present a microscopic approach in the framework of Sklyanin's quantum
separation of variables (SOV) for the exact solution of 1+1-dimensional quantum
field theories by integrable lattice regularizations. Sklyanin's SOV is the
natural quantum analogue of the classical method of separation of variables and
it allows a more symmetric description of classical and quantum integrability
w.r.t. traditional Bethe ansatz methods. Moreover, it has the advantage to be
applicable to a more general class of models for which its implementation gives
a characterization of the spectrum complete by construction. Our aim is to
introduce a method in this framework which allows at once to derive the
spectrum (eigenvalues and eigenvectors) and the dynamics (time dependent
correlation functions) of integrable quantum field theories (IQFTs). This
approach is presented for a paradigmatic example of relativistic IQFT, the
sine-Gordon model.


title: On the prewellordering associated to the dircted systems of mice

abstract:
  Working under $AD$, we investigate the length of prewellorderings given by
the iterates of $\M_{2k+1}$, which is the minimal proper class mouse with
$2k+1$ many Woodin cardinals. In particular, we answer some questions from
\cite{Hjorth01} (the discussion of the questions appears in the last section of
\cite{HjorthD}).


title:
Reconstruction Guarantee Analysis of Binary Measurement Matrices Based
  on Girth

abstract:
  Binary 0-1 measurement matrices, especially those from coding theory, were
introduced to compressed sensing (CS) recently. Good measurement matrices with
preferred properties, e.g., the restricted isometry property (RIP) and
nullspace property (NSP), have no known general ways to be efficiently checked.
Khajehnejad \emph{et al.} made use of \emph{girth} to certify the good
performances of sparse binary measurement matrices. In this paper, we examine
the performance of binary measurement matrices with uniform column weight and
arbitrary girth under basis pursuit. Explicit sufficient conditions of exact
reconstruction %only including $\gamma$ and $g$ are obtained, which improve the
previous results derived from RIP for any girth $g$ and results from NSP when
$g/2$ is odd. Moreover, we derive explicit $l_1/l_1$, $l_2/l_1$ and
$l_\infty/l_1$ sparse approximation guarantees. These results further show that
large girth has positive impacts on the performance of binary measurement
matrices under basis pursuit, and the binary parity-check matrices of good LDPC
codes are important candidates of measurement matrices.


title: "Pretty strong" converse for the quantum capacity of degradable channels

abstract:
  We exhibit a possible road towards a strong converse for the quantum capacity
of degradable channels. In particular, we show that all degradable channels
obey what we call a "pretty strong" converse: When the code rate increases
above the quantum capacity, the fidelity makes a discontinuous jump from 1 to
at most 0.707, asymptotically. A similar result can be shown for the private
(classical) capacity. Furthermore, we can show that if the strong converse
holds for symmetric channels (which have quantum capacity zero), then
degradable channels obey the strong converse: The above-mentioned asymptotic
jump of the fidelity at the quantum capacity is then from 1 down to 0.


title:
The classifying topos of a group scheme and invariants of symmetric
  bundles

abstract:
  Let $Y$ be a scheme in which 2 is invertible and let $V$ be a rank $n$ vector
bundle on $Y$ endowed with a non-degenerate symmetric bilinear form $q$. The
orthogonal group ${\bf O}(q)$ of the form $q$ is a group scheme over $Y$ whose
cohomology ring $H^*(B_{{\bf O}(q)},{\bf Z}/2{\bf Z})\simeq A_Y[HW_1(q),...,
HW_n(q)]$ is a polynomial algebra over the \'etale cohomology ring
$A_Y:=H^*(Y_{et},{\bf Z}/2{\bf Z})$ of the scheme $Y$. Here the $HW_i(q)$'s are
Jardine's universal Hasse-Witt invariants and $B_{{\bf O}(q)}$ is the
classifying topos of ${\bf O}(q)$ as defined by Grothendieck and Giraud. The
cohomology ring $H^*(B_{{\bf O}(q)},{\bf Z}/2{\bf Z})$ contains canonical
classes $\mathrm{det}[q]$ and $[C_q]$ of degree 1 and 2 respectively, which are
obtained from the determinant map and the Clifford group of $q$. The classical
Hasse-Witt invariants $w_i(q)$ live in the ring $A_Y$.
  Our main theorem provides a computation of ${det}[q]$ and $[C_{q}]$ as
polynomials in $HW_{1}(q)$ and $HW_{2}(q)$ with coefficients in $A_Y$ written
in terms of $w_1(q),w_2(q)\in A_Y$. This result is the source of numerous
standard comparison formulas for classical Hasses-Witt invariants of quadratic
forms. Our proof is based on computations with (abelian and non-abelian) Cech
cocycles in the topos $B_{{\bf O}(q)}$. This requires a general study of the
cohomology of the classifying topos of a group scheme, which we carry out in
the first part of this paper.


title: Detecting swift heavy ion irradiation effects with graphene

abstract:
  In this paper we show how single layer graphene can be utilized to study
swift heavy ion (SHI) modifications on various substrates. The samples were
prepared by mechanical exfoliation of bulk graphite onto SrTiO$_3$, NaCl and
Si(111), respectively. SHI irradiations were performed under glancing angles of
incidence and the samples were analysed by means of atomic force microscopy in
ambient conditions. We show that graphene can be used to check whether the
irradiation was successful or not, to determine the nominal ion fluence and to
locally mark SHI impacts. In case of samples prepared in situ, graphene is
shown to be able to catch material which would otherwise escape from the
surface.


title:
New results from the lattice on the theoretical inputs to the hadronic
  tau determination of V_us

abstract:
  Recent sum rule determinations of |V_us|, employing flavor-breaking
combinations of hadronic tau decay data, are significantly lower than either
expectations based on 3-family unitarity or determinations from K_ell3 and
Gamma[K_mu2]/Gamma[pi_mu2]. We use lattice data to investigate the
accuracy/reliability of the OPE representation of the flavor-breaking
correlator combination entering the tau decay analyses. The behavior of an
alternate correlator combination, constructed to reduce problems associated
with the slow convergence of the D = 2 OPE series, and entering an alternate
sum rule requiring both electroproduction cross-section and hadronic tau decay
data, is also investigated. Preliminary updates of both analyses, with the
lessons learned from the lattice data in mind, are also presented.


title:
The Rational Distance Problem for Isosceles Triangles with one rational
  side

abstract:
  For a triangle $\Delta$, let (P) denote the problem of the existence of
points in the plane of $\Delta$, that are at rational distance to the 3
vertices of $\Delta$. Answer to (P) is known to be positive in the following
situation: $\Delta$ has one rational side and the square of all sides are
rational. Further, the set of solution-points is dense in the plane of
$\Delta$. See [3] The reader can convince himself that the rationality of one
side is a reasonable minimum condition to set out, otherwise problem (P) would
stay somewhat hazy and scattered. Now, even with the assumption of one rational
side, problem (P) stays hard. In this note, we restrict our attention to
isosceles triangles, and provide a \textit{complete description} of such
triangles for which (P) has a positive answer.


title:
On the Rectilinear Shear of Compressible and Incompressible Elastic
  Slabs

abstract:
  We review some pseudo-planar deformations for the equations of incompressible
isotropic nonlinear elasticity first introduced in 1985 by Rajagopal and
Wineman. We extend this class of deformations to compressible isotropic and
transverse isotropic materials, and also consider the influence of gravity. We
consider some new approximate solutions and we discuss the possible relevance
of such solutions to the understanding of the complex structure of the fields
equations of nonlinear elasticity, using weakly nonlinear theories.


title:
Mapping the network structure of science parks: An exploratory study of
  cross-sectoral interactions reflected on the web

abstract:
  This study introduces a method based on link analysis to investigate the
structure of the R&D support infrastructure associated with science parks in
order to determine whether this webometric approach gives plausible results.
Three science parks from Yorkshire and the Humber in the UK were analysed with
webometric and social network analysis techniques. Interlinking networks were
generated through the combination of two different data sets extracted from
three sources (Yahoo!, Bing, SocSciBot). These networks suggest that
institutional sectors, representing business, universities and public bodies,
are primarily tied together by a core formed by research institutions, support
structure organisations and business developers. The comparison of the findings
with traditional indicators suggests that the web-based networks reflect the
offline conditions and policy measures adopted in the region, giving some
evidence that the webometric approach is plausible to investigating science
park networks. This is the first study that applies a web-based approach to
investigate to what extent the science parks facilitate a closer interaction
between the heterogeneous organisations that converge in R&D networks. This
indicates that link analysis may help to get a first insight into the
organisation of the R&D support infrastructure provided by science parks.


title: Functional calculus for semigroup generators via transference

abstract:
  In this article we apply a recently established transference principle in
order to obtain the boundedness of certain functional calculi for semigroup
generators. In particular, it is proved that if $-A$ generates a
$C_0$-semigroup on a Hilbert space, then for each $\tau>0$ the operator $A$ has
a bounded calculus for the closed ideal of bounded holomorphic functions on a
(sufficiently large) right half-plane that satisfy
$f(z)=O(e^{-\tau\textrm{Re}(z)})$ as $|z|\rightarrow \infty$. The bound of this
calculus grows at most logarithmically as $\tau\searrow 0$. As a consequence,
$f(A)$ is a bounded operator for each holomorphic function $f$ (on a right
half-plane) with polynomial decay at $\infty$. Then we show that each semigroup
generator has a so-called (strong) $m$-bounded calculus for all
$m\in\mathbb{N}$, and that this property characterizes semigroup generators.
Similar results are obtained if the underlying Banach space is a UMD space.
Upon restriction to so-called $\gamma$-bounded semigroups, the Hilbert space
results actually hold in general Banach spaces.


title:
Phase transition in equilibrium fluctuations of symmetric slowed
  exclusion

abstract:
  We analyze the equilibrium fluctuations of the density, current and tagged
particle in symmetric exclusion with a slow bond. The system evolves in the
one-dimensional lattice and the jump rate is everywhere equal to one except at
the slow bond where it is $\alpha n^-\beta$, where $\alpha,\beta\geq{0}$ and
$n$ is the scaling parameter. Depending on the regime of $\beta$, we find three
different behaviors for the limiting fluctuations whose covariances are
explicitly computed. In particular, for the critical value $\beta=1$, starting
a tagged particle near the slow bond, we obtain a family of gaussian processes
indexed in $\alpha$, interpolating a fractional brownian motion of Hurst
exponent 1/4 and the degenerate process equal to zero.


title:
Density functional theory analysis of flexural modes, elastic constants,
  and corrugations in strained graphene

abstract:
  Ab initio density functional theory has been used to analyze flexural modes,
elastic constants, and atomic corrugations on single and bi-layer graphene.
Frequencies of flexural modes are sensitive to compressive stress; its
variation under stress can be related to the anomalous thermal expansion via a
simple model based in classical Elasticity Theory [Phys. Rev. B 86, 144103].
Under compression, flexural modes are responsible for a long wavelength
rippling with a large amplitude and a marked anharmonic behavior. This is
compared with corrugations created by thermal fluctuations and the adsorption
of a light impurity (hydrogen). Typical values for the later are in the
sub-Angstrom regime, while maximum corrugations associated to bending modes
quickly increase up to a few Angstroms under a compressive stress, due to the
intrinsic instability of flexural modes


title: On Alexander-Conway polynomials of two-bridge links

abstract:
  We consider Conway polynomials of two-bridge links as Euler continuant
polynomials. As a consequence, we obtain new and elementary proofs of classical
Murasugi's 1958 alternating theorem and Hartley's 1979 trapezoidal theorem. We
give a modulo 2 congruence for links, which implies the classical Murasugi's
1971 congruence for knots. We also give sharp bounds for the coefficients of
Euler continuants and deduce bounds for the Alexander polynomials of two-bridge
links. These bounds improve and generalize those of Nakanishi Suketa'96. We
easily obtain some bounds for the roots of the Alexander polynomials of
two-bridge links. This is a partial answer to Hoste's conjecture on the roots
of Alexander polynomials of alternating knots.


title:
A type theoretical framework for natural language semantics: the
  Montagovian generative lexicon

abstract:
  We present a framework, named the Montagovian generative lexicon, for
computing the semantics of natural language sentences, expressed in many sorted
higher order logic. Word meaning is depicted by lambda terms of second order
lambda calculus (Girard's system F) with base types including a type for
propositions and many types for sorts of a many sorted logic. This framework is
able to integrate a proper treatment of lexical phenomena into a Montagovian
compositional semantics, including the restriction of selection which imposes
the nature of the arguments of a predicate, and the possible adaptation of a
word meaning to some contexts. Among these adaptations of a word's sense to the
context, ontological inclusions are handled by an extension of system F with
coercive subtyping that is introduced in the present paper. The benefits of
this framework for lexical pragmatics are illustrated on meaning transfers and
coercions, on possible and impossible copredication over different senses, on
deverbal ambiguities, and on "fictive motion". Next we show that the
compositional treatment of determiners, quantifiers, plurals,... are finer
grained in our framework. We then conclude with the linguistic, logical and
computational perspectives opened by the Montagovian generative lexicon.


title: Eigenvector dynamics under free addition

abstract:
  We investigate the evolution of a given eigenvector of a symmetric
(deterministic or random) matrix under the addition of a matrix in the Gaussian
orthogonal ensemble. We quantify the overlap between this single vector with
the eigenvectors of the initial matrix and identify precisely a "Cauchy-flight"
regime. In particular, we compute the local density of this vector in the
eigenvalues space of the initial matrix. Our results are obtained in a non
perturbative setting and are derived using the ideas of [O. Ledoit and S.
P\'ech\'e, Prob. Th. Rel. Fields, {\bf 151} 233 (2011)]. Finally, we give a
robust derivation of a result obtained in [R. Allez and J.-P. Bouchaud, Phys.
Rev. E {\bf 86}, 046202 (2012)] to study eigenspace dynamics in a
semi-perturbative regime.


title: SPIN Effects, QCD, and Jefferson Laboratory with 12 GeV electrons

abstract:
  QCD and Spin physics are playing important role in our understanding of
hadron structure. I will give a short overview of origin of hadron structure in
QCD and highlight modern understanding of the subject. Jefferson Laboratory is
undergoing an upgrade that will increase the energy of electron beam up to 12
GeV. JLab is one of the leading facilities in nuclear physics studies and once
operational in 2015 JLab 12 will be crucial for future of nuclear physics. I
will briefly discuss future studies in four experimental halls of Jefferson
Lab.


title:
A systematic empirical comparison of different approaches for
  normalizing citation impact indicators

abstract:
  We address the question how citation-based bibliometric indicators can best
be normalized to ensure fair comparisons between publications from different
scientific fields and different years. In a systematic large-scale empirical
analysis, we compare a traditional normalization approach based on a field
classification system with three source normalization approaches. We pay
special attention to the selection of the publications included in the
analysis. Publications in national scientific journals, popular scientific
magazines, and trade magazines are not included. Unlike earlier studies, we use
algorithmically constructed classification systems to evaluate the different
normalization approaches. Our analysis shows that a source normalization
approach based on the recently introduced idea of fractional citation counting
does not perform well. Two other source normalization approaches generally
outperform the classification-system-based normalization approach that we
study. Our analysis therefore offers considerable support for the use of
source-normalized bibliometric indicators.


title:
Nanoscale Surface Element Identification and Dopant Homogeneity in the
  High-$T_c$ Superconductor Pr$_x$Ca$_{1-x}$Fe$_2$As$_2$

abstract:
  We use scanning tunneling microscopy to determine the surface structure and
dopant distribution in Pr$_x$Ca$_{1-x}$Fe$_2$As$_2$, the highest-$T_c$ member
of the 122 family of iron-based superconductors. We identify the cleaved
surface termination by mapping the local tunneling barrier height, related to
the work function. We image the individual Pr dopants responsible for
superconductivity, and show that they do not cluster, but in fact repel each
other at short length scales. We therefore suggest that the low volume fraction
high-$T_c$ superconducting phase is unlikely to originate from Pr
inhomogeneity.


title:
$L^p$-Square Function Estimates on Spaces of Homogeneous Type and on
  Uniformly Rectifiable Sets

abstract:
  We establish square function estimates for integral operators on uniformly
rectifiable sets by proving a local $T(b)$ theorem and applying it to show that
such estimates are stable under the so-called big pieces functor. More
generally, we consider integral operators associated with Ahlfors-David regular
sets of arbitrary codimension in ambient quasi-metric spaces. The local $T(b)$
theorem is then used to establish an inductive scheme in which square function
estimates on so-called big pieces of an Ahlfors-David regular set are proved to
be sufficient for square function estimates to hold on the entire set.
Extrapolation results for $L^p$ and Hardy space versions of these estimates are
also established. Moreover, we prove square function estimates for integral
operators associated with variable coefficient kernels, including the Schwartz
kernels of pseudodifferential operators acting between vector bundles on
subdomains with uniformly rectifiable boundaries on manifolds.


title: Evaluation of a Supervised Learning Approach for Stock Market Operations

abstract:
  Data mining methods have been widely applied in financial markets, with the
purpose of providing suitable tools for prices forecasting and automatic
trading. Particularly, learning methods aim to identify patterns in time series
and, based on such patterns, to recommend buy/sell operations. The objective of
this work is to evaluate the performance of Random Forests, a supervised
learning method based on ensembles of decision trees, for decision support in
stock markets. Preliminary results indicate good rates of successful operations
and good rates of return per operation, providing a strong motivation for
further research in this topic.


title:
Response to comment "Measurement of mobility in dual-gated MoS2
  transistors"

abstract:
  In our previous paper, we reported on switchable monolayer MoS2 transistors
with a high on-off ratio and we claim that dielectric screening can be used to
increase the mobility of monolayer MoS2. We estimated its mobility using a
method previously applied by Lemme et al. to top-gated graphene nanoribbons. We
discuss here the comments raised by M. Fuhrer and J. Hone in their post
1301.4288 and give our own estimates of the possible errors in previous
mobility measurements and their origins.


title: Binary matroids and local complementation

abstract:
  We introduce a binary matroid M(IAS(G)) associated with a looped simple graph
G. M(IAS(G)) classifies G up to local equivalence, and determines the
delta-matroid and isotropic system associated with G. Moreover, a parametrized
form of its Tutte polynomial yields the interlace polynomials of G.


title: Mobility engineering and metal-insulator transition in monolayer MoS2

abstract:
  Two-dimensional (2D) materials are a new class of materials with interesting
physical properties and ranging from nanoelectronics to sensing and photonics.
In addition to graphene, the most studied 2D material, monolayers of other
layered materials such as semiconducting dichalcogenides MoS2 or WSe2 are
gaining in importance as promising insulators and channel materials for
field-effect transistors (FETs). The presence of a direct band gap in monolayer
MoS2 due to quantum mechanical confinement, allows room-temperature
field-effect transistors with an on/off ratio exceeding 108. The presence of
high-k dielectrics in these devices enhanced their mobility, but the mechanisms
are not well understood. Here, we report on electrical transport measurements
on MoS2 FETs in different dielectric configurations. Mobility dependence on
temperature shows clear evidence of the strong suppression of charge impurity
scattering in dual-gate devices with a top-gate dielectric together with phonon
scattering that shows a weaker than expected temperature dependence. High
levels of doping achieved in dual-gate devices also allow the observation of a
metal-insulator transition in monolayer MoS2. Our work opens up the way to
further improvements in 2D semiconductor performance and introduces MoS2 as an
interesting system for studying correlation effects in mesoscopic systems.


title:
Relaminarisation of Re_{\tau} = 100 channel flow with globally
  stabilising linear feedback control

abstract:
  The problems of nonlinearity and high dimension have so far prevented a
complete solution of the control of turbulent flow. Addressing the problem of
nonlinearity, we propose a flow control strategy which ensures that the energy
of any perturbation to the target profile decays monotonically. The
controller's estimate of the flow state is similarly guaranteed to converge to
the true value. We present a one-time off-line synthesis procedure, which
generalises to accommodate more restrictive actuation and sensing arrangements,
with conditions for existence for the controller given in this case. The
control is tested in turbulent channel flow ($Re_\tau=100$) using full-domain
sensing and actuation on the wall-normal velocity. Concentrated at the point of
maximum inflection in the mean profile, the control directly counters the
supply of turbulence energy arising from the interaction of the wall-normal
perturbations with the flow shear. It is found that the control is only
required for the larger-scale motions, specifically those above the scale of
the mean streak spacing. Minimal control effort is required once laminar flow
is achieved. The response of the near-wall flow is examined in detail, with
particular emphasis on the pressure and wall-normal velocity fields, in the
context of Landahl's theory of sheared turbulence.


title: On distinguished orbits of reductive representations

abstract:
  Let $G$ be a real reductive Lie group and ${\tau}:G \longrightarrow GL(V)$ be
a real reductive representation of $G$ with (restricted) moment map $m_{\ggo}:
V-{0} \longrightarrow \ggo$. In this work, we introduce the notion of "nice
space" of a real reductive representation to study the problem of how to
determine if a $G$-orbit is "distinguished" (i.e. it contains a critical point
of the norm squared of $m_{\ggo}$). We give an elementary proof of the
well-known convexity theorem of Atiyah-Guillemin-Sternberg in our particular
case and we use it to give an easy-to-check sufficient condition for a
$G$-orbit of a element in a nice space to be distinguished. In the case where
$G$ is algebraic and $\tau$ is a rational representation, the above condition
is also necessary (making heavy use of recent results of M. Jablonski),
obtaining a generalization of Nikolayevsky's nice basis criterium. We also
provide useful characterizations of nice spaces in terms of the weights of
$\tau$. Finally, some applications to ternary forms and minimal metrics on
nilmanifolds are presented.


title:
Bayesian Conditional Tensor Factorizations for High-Dimensional
  Classification

abstract:
  In many application areas, data are collected on a categorical response and
high-dimensional categorical predictors, with the goals being to build a
parsimonious model for classification while doing inferences on the important
predictors. In settings such as genomics, there can be complex interactions
among the predictors. By using a carefully-structured Tucker factorization, we
define a model that can characterize any conditional probability, while
facilitating variable selection and modeling of higher-order interactions.
Following a Bayesian approach, we propose a Markov chain Monte Carlo algorithm
for posterior computation accommodating uncertainty in the predictors to be
included. Under near sparsity assumptions, the posterior distribution for the
conditional probability is shown to achieve close to the parametric rate of
contraction even in ultra high-dimensional settings. The methods are
illustrated using simulation examples and biomedical applications.


title:
Attracting and repelling Lagrangian coherent structures from a single
  computation

abstract:
  Hyperbolic Lagrangian Coherent Structures (LCSs) are locally most repelling
or most attracting material surfaces in a finite-time dynamical system. To
identify both types of hyperbolic LCSs at the same time instance, the standard
practice has been to compute repelling LCSs from future data and attracting
LCSs from past data. This approach tacitly assumes that coherent structures in
the flow are fundamentally recurrent, and hence gives inconsistent results for
temporally aperiodic systems. Here we resolve this inconsistency by showing how
both repelling and attracting LCSs are computable at the same time instance
from a single forward or a single backward run. These LCSs are obtained as
surfaces normal to the weakest and strongest eigenvectors of the Cauchy-Green
strain tensor.


title: Single and multiple consecutive permutation motif search

abstract:
  Let $t$ be a permutation (that shall play the role of the {\em text}) on
$[n]$ and a pattern $p$ be a sequence of $m$ distinct integer(s) of $[n]$,
$m\leq n$. The pattern $p$ occurs in $t$ in position $i$ if and only if $p_1...
p_m$ is order-isomorphic to $t_i... t_{i+m-1}$, that is, for all $1 \leq k<
\ell \leq m$, $p_k>p_\ell$ if and only if $t_{i+k-1}>t_{i+\ell-1}$. Searching
for a pattern $p$ in a text $t$ consists in identifying all occurrences of $p$
in $t$. We first present a forward automaton which allows us to search for $p$
in $t$ in $O(m^2\log \log m +n)$ time. We then introduce a Morris-Pratt
automaton representation of the forward automaton which allows us to reduce
this complexity to $O(m\log \log m +n)$ at the price of an additional amortized
constant term by integer of the text. Both automata occupy $O(m)$ space. We
then extend the problem to search for a set of patterns and exhibit a specific
Aho-Corasick like algorithm. Next we present a sub-linear average case search
algorithm running in $O(\frac{m\log m}{\log\log m}+\frac{n\log m}{m\log\log
m})$ time, that we eventually prove to be optimal on average.