title: Spin-Statistics Correlations in Various Noncommutative Field Theories

abstract:
  In this thesis we study field theories written on a particular model of
noncommutative spacetime, the Groenewold-Moyal (GM) plane. We start with
briefly reviewing the novel features of field theories on GM plane e.g. the
$\ast$-product, restoration of Poincar\'e-Hopf symmetry and twisted commutation
relations. We then discuss our work on renormalization of field theories on GM
plane. We show that any generic noncommutative theory involving pure matter
fields with polynomial interactions, is a renormalizable theory if the
analogous commutative theory is renormalizable. We further show that all such
noncommutative theories will have same fixed points and $\beta$-functions for
the couplings, as that of the analogous commutative theory. The unique feature
of these field theories is the twisted statistics obeyed by the particles.
Motivated by it, we look at the possibility of twisted statistics by deforming
internal symmetries instead of spacetime symmetries. We construct two different
twisted theories which can be viewed as internal symmetry analogue of the GM
plane and dipole field theories which arise in the low energy limit of certain
string configurations. We further study their various properties like the issue
of causality and the scattering formalism. Having studied the mathematical
properties of noncommutative and twisted internal symmetries we move on to
discuss their potential phenomenological signatures. We first discuss the
noncommutative thermal correlation functions and show that because of the
twisted statistics, all correlation functions except two-point function get
modified. Finally we discuss the modifications in Hanbury-Brown Twiss (HBT)
correlation functions due to twisted statistics on GM plane and the potential
of observing signatures of noncommutativity by doing a HBT correlation
experiment with Ultra High Energy Cosmic Rays (UHECRs).


title: Empirical Measures and Vlasov Hierarchies

abstract:
  The present note reviews some aspects of the mean field limit for Vlasov type
equations with Lipschitz continuous interaction kernel. We discuss in
particular the connection between the approach involving the N-particle
empirical measure and the formulation based on the BBGKY hierarchy. This leads
to a more direct proof of the quantitative estimates on the propagation of
chaos obtained on a more general class of interacting systems in [S.Mischler,
C. Mouhot, B. Wennberg, arXiv:1101.4727]. Our main result is a stability
estimate on the BBGKY hierarchy uniform in the number of particles, which
implies a stability estimate in the sense of the Monge-Kantorovich distance
with exponent 1 on the infinite mean field hierarchy. This last result
amplifies Spohn's uniqueness theorem [H. Spohn, Math. Meth. Appl. Sci. 3
(1981), 445-455].


title: Heterotic Model Building: 16 Special Manifolds

abstract:
  We study heterotic model building on 16 specific Calabi-Yau manifolds
constructed as hypersurfaces in toric four-folds. These 16 manifolds are the
only ones among the more than half a billion manifolds in the Kreuzer-Skarke
list with a non-trivial first fundamental group. We classify the line bundle
models on these manifolds, both for SU(5) and SO(10) GUTs, which lead to
consistent supersymmetric string vacua and have three chiral families. A total
of about 29000 models is found, most of them corresponding to SO(10) GUTs.
These models constitute a starting point for detailed heterotic model building
on Calabi-Yau manifolds in the Kreuzer-Skarke list. The data for these models
can be downloaded here:
http://www-thphys.physics.ox.ac.uk/projects/CalabiYau/toricdata/index.html


title: Mass inflation inside black holes revisited

abstract:
  The mass inflation phenomenon implies that black hole interiors are unstable
due to a back-reaction divergence of the perturbed black hole mass function at
the Cauchy horizon. Weak point in the standard mass inflation calculations is
in a fallacious using of the global Cauchy horizon as a place for the maximal
growth of the back-reaction perturbations instead of the local inner apparent
horizon. It is derived the new spherically symmetric back-reaction solution for
two counter-streaming light-like fluxes near the inner apparent horizon of the
charged black hole by taking into account its separation from the Cauchy
horizon. In this solution the back-reaction perturbations of the background
metric are truly the largest at the inner apparent horizon, but, nevertheless,
remain small. The back reaction, additionally, removes the infinite blue-shift
singularity at the inner apparent horizon and at the Cauchy horizon.


title: Choosability of Graphs with Bounded Order: Ohba's Conjecture and Beyond

abstract:
  The \emph{choice number} of a graph $G$, denoted $\ch(G)$, is the minimum
integer $k$ such that for any assignment of lists of size $k$ to the vertices
of $G$, there is a proper colouring of $G$ such that every vertex is mapped to
a colour in its list. For general graphs, the choice number is not bounded
above by a function of the chromatic number.
  In this thesis, we prove a conjecture of Ohba which asserts that
$\ch(G)=\chi(G)$ whenever $|V(G)|\leq 2\chi(G)+1$. We also prove a
strengthening of Ohba's Conjecture which is best possible for graphs on at most
$3\chi(G)$ vertices, and pose several conjectures related to our work.


title:
Inter-dependent Tissue Growth and Turing Patterning in a Model for Long
  Bone Development

abstract:
  The development of long bones requires a sophisticated spatial organization
of cellular signaling, proliferation, and differentiation programs. How such
spatial organization emerges on the growing long bone domain is still
unresolved. Based on the reported biochemical interactions we developed a
regulatory model for the core signaling factors IHH, PTCH1, and PTHrP and
included two cell types, proliferating/resting chondrocytes and
(pre-)hypertrophic chondrocytes. We show that the reported IHH-PTCH1
interaction gives rise to a Schnakenberg-type Turing kinetics, and that
inclusion of PTHrP is important to achieve robust patterning when coupling
patterning and tissue dynamics. The model reproduces relevant spatiotemporal
gene expression patterns, as well as a number of relevant mutant phenotypes. In
summary, we propose that a ligand-receptor based Turing mechanism may control
the emergence of patterns during long bone development, with PTHrP as an
important mediator to confer patterning robustness when the sensitive Turing
system is coupled to the dynamics of a growing and differentiating tissue. We
have previously shown that ligand-receptor based Turing mechanisms can also
result from BMP-receptor and GDNF-receptor interactions, and that these
reproduce the wildtype and mutant patterns during digit formation in limbs and
branching morphogenesis in lung and kidneys. Receptor-ligand interactions may
thus constitute a general mechanism to generate Turing patterns in nature.


title: Fluid Flow at Branching Junctions

abstract:
  The flow of fluids at branching junctions plays important kinematic and
dynamic roles in most biological and industrial flow systems. The present paper
highlights some key issues related to the flow of fluids at these junctions
with special emphasis on the biological flow networks particularly blood
transportation vasculature.


title: Special elements in lattices of semigroup varieties

abstract:
  We survey results concerning special elements of nine types (modular,
lower-modular, upper-modular, cancellable, distributive, codistributive,
standard, costandard and neutral elements) in the lattice of all semigroup
varieties and certain its sublattices, mainly in the lattices of all
commutative varieties and of all overcommutative ones. Several open questions
are formulated. The work is regularly updated and modified as new results
and/or articles appear.


title: Space-time holomorphic solutions of Navier-Stokes equations

abstract:
  We introduce a concept of space-time holomorphic solutions of partial
differential equations and construct a meromorphic solution of Navier-Stokes
equations.


title: On the divisibility of the truncated hypergeometric function 3F2

abstract:
  We prove a result on the divisibility of the truncated hypergeometric
function 3F2.


title:
On limitation of mass spectrum in non-Hermitian $\cal PT$-symmetric
  models with the $\gamma_5$-dependent mass term

abstract:
  The modified Dirac equations for the massive particles with the replacement
of the physical mass $m$ with the help of the relation $m\rightarrow m_1 +
\gamma_5 m_2$ are investigated. It is shown that for a free fermion theory with
a $\gamma_5$ mass term, the finiteness of the mass spectrum at the value $
m_{max}= {m_1}^2/2m_2$ takes place. In this case the region of the unbroken
$\cal PT$-symmetry may be expressed by means of the simple restriction of the
physical mass $m\leq m_{max}$. Furthermore, we have that the areas of unbroken
$\cal PT$-symmetry $m_1\geq m_2\geq 0$, which guarantees the reality values of
the physical mass $m$, consists of three different parametric subregions: i)
$0\leq m_2 < m_1/\sqrt{2}$, \,\,ii) $m_2=m_1/\sqrt{2}=m_{max},$
\,\,(iii)$m_1/\sqrt{2}< m_2 \leq m_1$. It is vary important, that only the
first subregion (i) defined mass values $m_1,m_2,$ which correspond to the
description of traditional particles in the modified models, because this area
contain the possibility transform the modified model to the ordinary Dirac
theory. The second condition (ii) is defined the "maximon" - the particle with
maximal mass $m=m_{max}$. In the case (iii) we have to do with the unusual or
"exotic" particles for description of which Hamiltonians and equations of
motion have no a Hermitian limit. The formulated criterions may be used as a
major test in the process of the division of considered models into ordinary
and "exotic fermion theories".


title:
The Galerkin Method for Perturbed Self-Adjoint Operators and
  Applications

abstract:
  We consider the Galerkin method for approximating the spectrum of an operator
$T+A$ where $T$ is semi-bounded self-adjoint and $A$ satisfies a relative
compactness condition. We show that the method is reliable in all regions where
it is reliable for the unperturbed problem - which always contains
$\mathbb{C}\backslash\mathbb{R}$. The results lead to a new technique for
identifying eigenvalues of $T$, and for identifying spectral pollution which
arises from applying the Galerkin method directly to $T$. The new technique
benefits from being applicable on the form domain.


title: Minimal potential results for the Schrodinger equation in a slab

abstract:
  Consider the Schrodinger equation -\Delta u =(k+V) u in an infinite slab S=
\R^{n-1}x (0,1), where V is a bounded potential supported on a set D of finite
measure. We prove necessary conditions for the existence of nontrivial
admissible solutions. These conditions involve the sup. of |V|, the measure of
D, and the distance of k from the "special set" {\pi^2 m^2, m positive
integer}. In many cases, these inequalities are sharp.


title:
Measurement and Analysis of Fission Rates in a Spherical Mockup of
  Uranium and Polyethylene

abstract:
  Measurements of the reaction rate distribution were carried out using two
kinds of Plate Micro Fission Chamber(PMFC). The first is a depleted uranium
chamber and the second an enriched uranium chamber. The material in the
depleted uranium chamber is strictly the same as the material in the uranium
assembly. With the equation solution to conduct the isotope contribution
correction, the fission rate of 238U and 235U were obtained from the fission
rate of depleted uranium and enriched uranium. And then, the fission count of
238U and 235U in an individual uranium shell was obtained. In this work, MCNP5
and continuous energy cross sections ENDF/BV.0 were used for the analysis of
fission rate distribution and fission count. The calculated results were
compared with the experimental ones. The calculation of fission rate of DU and
EU were found to agree with the measured ones within 10% except at the
positions in polyethylene region and the two positions near the outer surface.
Beacause the fission chamber was not considered in the calculation of the
fission counts of 238U and 235U, the calculated results did not agree well with
the experimental ones.


title:
Some New Light-cone Time Dependent Solutions in Deformed pp-wave
  Backgrounds

abstract:
  Brane solutions in time \ light-cone time dependent backgrounds are of
interest in order to gain a deeper understanding of the physics associated with
cosmological and null singularities. In this paper, we report both brane
solutions and their bound states in light-cone time dependent pp wave-like
backgrounds. We show that the backgrounds our solutions live in are all
cosmologically singular (lightlike) at the classical level. A spacetime
supersymmetry analysis of the backgrounds reveals that they retain 1/8 of the
full type IIB supersymmetry.


title: Absence of hot gas within the Wolft-Rayet Bubble around WR16

abstract:
  We present the analysis of XMM-Newton archival observations towards the
Wolf-Rayet (WR) bubble around WR16. Despite the closed bubble morphology of
this WR nebula, the XMM-Newton observations show no evidence of diffuse
emission in its interior as in the similar WR bubbles NGC6888 and S308. We use
the present observations to estimate a 3-\sigma upper limit to the X-ray
luminosity in the 0.3-1.5 keV energy band equal to 7.4x10^{32} erg s^{-1} for
the diffuse emission from the WR nebula, assuming a distance of 2.37 kpc. The
WR nebula around WR16 is the fourth observed by the current generation of X-ray
satellites and the second not detected. We also examine FUSE spectra to search
for nebular O VI absorption lines in the stellar continuum of WR16. The present
far-UV data and the lack of measurements of the dynamics of the optical WR
bubble do not allow us to confirm the existence of a conductive layer of gas at
T~3x10^5 K between the cold nebular gas and the hot gas in its interior. The
present observations result in an upper limit of n_e < 0.6 cm^-3 on the
electron density of the X-ray emitting material within the nebula.


title:
A Multi-Strain Virus Model with Infected Cell Age Structure: Application
  to HIV

abstract:
  We consider a general mathematical model of a within-host viral infection
with $n$ virus strains and explicit age-since-infection structure for infected
cells. In the model, multiple virus strains compete for a population of target
cells. Cells infected with virus strain $i\in\left\{1,...,n\right\}$ die at
per-capita rate $\delta_i(a)$ and produce virions at per-capita rate $p_i(a)$,
where $\delta_i(a)$ and $p_i(a)$ are functions of the age-since-infection of
the cell. Viral strain $i$ has a basic reproduction number, $\mathcal{R}_i$,
and a corresponding positive single strain equilibrium, $E_i$, when
$\mathcal{R}_i>1$. If $\mathcal{R}_i<1$, then the total concentration of virus
strain $i$ will converge to 0 asymptotically. The main result is that when
$\max_i \mathcal{R}_i>1$ and all of the reproduction numbers are distinct, i.e.
$\mathcal{R}_i\neq \mathcal{R}_j \ \forall i\neq j$, the viral strain with the
maximal basic reproduction number competitively excludes the other strains. As
an application of the model, HIV evolution is considered and simulations are
provided.


title:
API design for machine learning software: experiences from the
  scikit-learn project

abstract:
  Scikit-learn is an increasingly popular machine learning li- brary. Written
in Python, it is designed to be simple and efficient, accessible to
non-experts, and reusable in various contexts. In this paper, we present and
discuss our design choices for the application programming interface (API) of
the project. In particular, we describe the simple and elegant interface shared
by all learning and processing units in the library and then discuss its
advantages in terms of composition and reusability. The paper also comments on
implementation details specific to the Python ecosystem and analyzes obstacles
faced by users and developers of the library.


title:
Energy-Neutral Source-Channel Coding with Battery and Memory Size
  Constraints

abstract:
  We study energy management policies for the compression and transmission of
source data collected by an energy-harvesting sensor node with a finite energy
buffer (e.g., rechargeable battery) and a finite data buffer (memory) between
source encoder and channel encoder. The sensor node can adapt the source and
channel coding rates depending on the observation and channel states. In such a
system, the absence of precise information about the amount of energy available
in the future is a key challenge. We provide analytical bounds and scaling laws
for the average distortion that depend on the size of the energy and data
buffers. We furthermore design a resource allocation policy that achieves
almost optimal distortion scaling. Our results demonstrate that the energy
leakage of state of art energy management policies can be avoided by jointly
controlling the source and channel coding rates.


title: Fractional Operators, Dirichlet Averages, and Splines

abstract:
  Fractional differential and integral operators, Dirichlet averages, and
splines of complex order are three seemingly distinct mathematical subject
areas addressing different questions and employing different methodologies. It
is the purpose of this paper to show that there are deep and interesting
relationships between these three areas. First a brief introduction to
fractional differential and integral operators defined on Lizorkin spaces is
presented and some of their main properties exhibited. This particular approach
has the advantage that several definitions of fractional derivatives and
integrals coincide. We then introduce Dirichlet averages and extend their
definition to an infinite-dimensional setting that is needed to exhibit the
relationships to splines of complex order. Finally, we focus on splines of
complex order and, in particular, on cardinal B-splines of complex order. The
fundamental connections to fractional derivatives and integrals as well as
Dirichlet averages are presented.


title: Fractal Hypersurfaces, Wavelet Sets and Affine Weyl Groups

abstract:
  In these lecture notes we present connections between the theory of iterated
function systems, in particular those attractors that are graphs of
multivariate real-valued fractal functions, foldable figures and affine Weyl
groups, and wavelet sets.


title: Ensemble approaches for improving community detection methods

abstract:
  Statistical estimates can often be improved by fusion of data from several
different sources. One example is so-called ensemble methods which have been
successfully applied in areas such as machine learning for classification and
clustering. In this paper, we present an ensemble method to improve community
detection by aggregating the information found in an ensemble of community
structures. This ensemble can found by re-sampling methods, multiple runs of a
stochastic community detection method, or by several different community
detection algorithms applied to the same network. The proposed method is
evaluated using random networks with community structures and compared with two
commonly used community detection methods. The proposed method when applied on
a stochastic community detection algorithm performs well with low computational
complexity, thus offering both a new approach to community detection and an
additional community detection method.


title: Local fractal functions and function spaces

abstract:
  We introduce local iterated function systems and present some of their basic
properties. A new class of local attractors of local iterated function systems,
namely local fractal functions, is constructed. We derive formulas so that
these local fractal functions become elements of various function spaces, such
as the Lebesgue spaces $L^p$, the smoothness spaces $C^n$, the homogeneous
H\"older spaces $\dot{C}^s$, and the Sobolev spaces $W^{m,p}$.


title:
Semi-analytic single-channel and cross-channel nonlinear interference
  spectra in highly-dispersed WDM coherent optical links with rectangular
  signal spectra

abstract:
  We provide new single-integral formulas of the power spectral density of
single-channel and cross-channel nonlinear interference in highly-dispersed
coherent optical links for which the Gaussian Noise model [1], [2] applies.


title: Generating Keys in Elliptic Curve Cryptosystems

abstract:
  In this paper, we will present how to find keys elliptic curve cryptosystems
(ECC) with simple tools of Delphi 7 console application, using the software
problem solving of the scalar point multiplication in the field GF(p), where p
is an arbitrary prime number.


title: High-pressure cupric oxide: a room-temperature multiferroic

abstract:
  Multiferroic materials, in which ferroelectric and magnetic ordering coexist,
are of fundamental interest for the development of multi-state memory devices
that allow for electrical writing and non-destructive magnetic read-out
operation. The great challenge is to create multiferroic materials that operate
at room-temperature and have a large ferroelectric polarization P. Cupric
oxide, CuO, is promising because of its large P ~ 10^{2} {\mu}C.m^{-2}, but is
unfortunately only multiferroic in a temperature range of 20 K, from 210 to 230
K. Here, using a combination of density functional theory and Monte Carlo
calculations, we establish that pressure-driven phase competition induces a
giant stabilization of the multiferroic phase of CuO, which at 20-40 GPa
becomes stable in a domain larger than 300 K, from 0 to T > 300 K. Thus, under
high-pressure, CuO is predicted to be a room-temperature multiferroic with
large polarization.


title:
A unified approach to determining forms for the 2D Navier-Stokes
  equations - the general interpolants case

abstract:
  In this paper we show that the long time dynamics (the global attractor) of
the 2D Navier-Stokes equation is embedded in the long time dynamics of an
ordinary differential equation, named {\it determining form}, in a space of
trajectories which is isomorphic to $C^1_b(\bR; \bR^N)$, for $N$ large enough
depending on the physical parameters of the Navier-Stokes equations. We present
a unified approach based on interpolant operators that are induced by any of
the determining parameters for the Navier-Stokes equations, namely, determining
nodal values, Fourier modes, finite volume elements, finite elements, etc...
There are two immediate and interesting consequences of this unified approach.
The first is that the constructed determining form has a Lyapunov function,
thus its solutions converge, as time goes to infinity, to the set of steady
states of the determining form. The second is that these steady states of the
determining form are identified, one-to-one, with the trajectories on the
global attractor of the Navier-Stokes equations. It is worth adding that this
unified approach is general enough that it applies, in an almost
straightforward manner, to a whole class of dissipative dynamical systems.


title:
Forward Hysteresis and Backward Bifurcation Caused by Culling in an
  Avian Influenza Model

abstract:
  The emerging threat of a human pandemic caused by the H5N1 avian influenza
virus strain magnifies the need for controlling the incidence of H5N1 infection
in domestic bird populations. Culling is one of the most widely used control
measures and has proved effective for isolated outbreaks. However, the
socio-economic impacts of mass culling, in the face of a disease which has
become endemic in many regions of the world, can affect the implementation and
success of culling as a control measure. We use mathematical modeling to
understand the dynamics of avian influenza under different culling approaches.
We incorporate culling into an SI model by considering the per capita culling
rates to be general functions of the number of infected birds. Complex dynamics
of the system, such as backward bifurcation and forward hysteresis, along with
bi-stability, are detected and analyzed for two distinct culling scenarios. In
these cases, employing other control measures temporarily can drastically
change the dynamics of the solutions to a more favorable outcome for disease
control.


title: Algorithms versus Circuit Lower Bounds

abstract:
  Different techniques have been used to prove several transference theorems of
the form "nontrivial algorithms for a circuit class C yield circuit lower
bounds against C". In this survey we revisit many of these results. We discuss
how circuit lower bounds can be obtained from derandomization, compression,
learning, and satisfiability algorithms. We also cover the connection between
circuit lower bounds and useful properties, a notion that turns out to be
fundamental in the context of these transference theorems. Along the way, we
obtain a few new results, simplify several proofs, and show connections
involving different frameworks. We hope that our presentation will serve as a
self-contained introduction for those interested in pursuing research in this
area.


title:
Search for a new bottomonium state decaying to Upsilon(1S) pi+ pi- in pp
  collisions at sqrt(s) = 8 TeV

abstract:
  The results of a search for the bottomonium counterpart, denoted as Xb, of
the exotic charmonium state X(3872) is presented. The analysis is based on a
sample of pp collisions at sqrt(s) = 8 TeV collected by the CMS experiment at
the LHC, corresponding to an integrated luminosity of 20.7 inverse femtobarns.
The search looks for the exclusive decay channel Xb to Upsilon(1S) pi+ pi-
followed by Upsilon(1S) to mu+ mu-. No evidence for an Xb signal is observed.
Upper limits are set at the 95% confidence level on the ratio of the inclusive
production cross sections times the branching fractions to Upsilon(1S) pi+ pi-
of the Xb and the Upsilon(2S). The upper limits on the ratio are in the range
0.9-5.4% for Xb masses between 10 and 11 GeV. These are the first upper limits
on the production of a possible Xb at a hadron collider.


title: Colored Packets with Deadlines and Metric Space Transition Cost

abstract:
  We consider scheduling of colored packets with transition costs which form a
general metric space. We design a $1 - O(\sqrt{MST(G) / L})$ competitive
algorithm. Our main result is a hardness result of $1 - \Omega(\sqrt{MST(G) /
L})$ which matches the competitive ratio of the algorithm for each metric space
separately. In particular, we improve the hardness result of Azar at el. 2009
for uniform metric spaces.
  We also extend our result to weighted directed graphs which obey the
triangular inequality and show a $1 - O(\sqrt{TSP(G) / L})$ competitive
algorithm and a nearly-matching hardness result. In proving our hardness
results we use some interesting non-standard embedding.


title: The resolving number of a graph

abstract:
  We study a graph parameter related to resolving sets and metric dimension,
namely the resolving number, introduced by Chartrand, Poisson and Zhang. First,
we establish an important difference between the two parameters: while
computing the metric dimension of an arbitrary graph is known to be NP-hard, we
show that the resolving number can be computed in polynomial time. We then
relate the resolving number to classical graph parameters: diameter, girth,
clique number, order and maximum degree. With these relations in hand, we
characterize the graphs with resolving number 3 extending other studies that
provide characterizations for smaller resolving number.


title: Wolff's Ideal Theorem on Qp Spaces

abstract:
  For $p\in(0,1),$ let $Q_p$ spaces be the space of all analytic functions on
the unit disk $\mathbb{D}$ such that $|f'(z) | ^2 (1-| z| ^2)^p dA(z)$ is a $p$
- Carleson measure. In this paper, we prove that the Wolff's Ideal Theorem on
$H^\infty{(\mathbb{D})}$ can be extended to the Banach algebra
$H^{\infty}(\mathbb{D})\cap Q_{p}$, and also to the multiplier algebra on $Q_p$
spaces.


title: Billey's formula in combinatorics, geometry, and topology

abstract:
  In this expository paper we describe a powerful combinatorial formula and its
implications in geometry, topology, and algebra. This formula first appeared in
the appendix of a book by Andersen, Jantzen, and Soergel. Sara Billey
discovered it independently five years later, and it played a prominent role in
her work to evaluate certain polynomials closely related to Schubert
polynomials.
  Billey's formula relates many pieces of Schubert calculus: the geometry of
Schubert varieties, the action of the torus on the flag variety, combinatorial
data about permutations, the cohomology of the flag variety and of the Schubert
varieties, and the combinatorics of root systems (generalizing inversions of a
permutation). Combinatorially, Billey's formula describes an invariant of pairs
of elements of a Weyl group. On its face, this formula is a combination of
roots built from subwords of a fixed word. As we will see, it has deeper
geometric and topological meaning as well: (1) It tells us about the tangent
spaces at each permutation flag in each Schubert variety. (2) It tells us about
singular points in Schubert varieties. (3) It tells us about the values of
Kostant polynomials. Billey's formula also reflects an aspect of GKM theory,
which is a way of describing the torus-equivariant cohomology of a variety just
from information about the torus-fixed points in the variety.
  This paper will also describe some applications of Billey's formula,
including concrete combinatorial descriptions of Billey's formula in special
cases, and ways to bootstrap Billey's formula to describe the equivariant
cohomology of subvarieties of the flag variety to which GKM theory does not
apply.


title: Piterbarg Theorems for Chi-processes with Trend

abstract:
  Let $\chi_n(t) = (\sum_{i=1}^n X_i^2(t))^{1/2},t\ge0$ be a chi-process with
$n$ degrees of freedom where $X_i$'s are independent copies of some generic
centered Gaussian process $X$. This paper derives the exact asymptotic behavior
of P{\sup_{t\in[0,T]} \chi_n(t)>u} as u \to \infty, where $T$ is a given
positive constant, and $g(\cdot)$ is some non-negative bounded measurable
function. The case $g(t)\equiv0$ is investigated in numerous contributions by
V.I. Piterbarg. Our novel asymptotic results for both stationary and
non-stationary $X$are referred to as Piterbarg theorems for chi-processes with
trend.


title: Extremes of alpha(t)-locally Stationary Gaussian Random Fields

abstract:
  This contribution derives the exact asymptotic behaviour of the supremum of
alpha(t)-locally stationary Gaussian random fields over a finite hypercube. We
present two applications of our result; the first one deals with extremes of
ggregate multifractional Brownian motions, whereas the second application
establishes the exact asymptotics of the supremum of chi-processes generated by
multifractional Brownian motions.


title: An Efficient Approach to Ab Initio Monte Carlo Simulation

abstract:
  We present a Nested Markov chain Monte Carlo (NMC) scheme for building
equilibrium averages based on accurate potentials such as density functional
theory. Metropolis sampling of a reference system, defined by an inexpensive
but approximate potential, was used to substantially decorrelate configurations
at which the potential of interest was evaluated, thereby dramatically reducing
the number needed to build ensemble averages at a given level of precision. The
efficiency of this procedure was maximized on-the-fly through variation of the
reference system thermodynamic state (characterized here by its inverse
temperature $\beta^0$), which was otherwise unconstrained. Local density
approximation (LDA) results are presented for shocked states of argon at
pressures from 4 to 60 GPa, where - depending on the quality of the reference
system potential - acceptance probabilities were enhanced by factors of 1.2-28
relative to unoptimized NMC. The optimization procedure compensated strongly
for reference potential shortcomings, as evidenced by significantly higher
speedups when using a reference potential of lower quality. The efficiency of
optimized NMC is shown to be competitive with that of standard ab initio
molecular dynamics in the canonical ensemble.


title:
Topological Uniform Superfluid and FFLO Phases in 3D to 1D crossover of
  spin-orbit coupled Fermi gases

abstract:
  We consider the quasi-one dimensional system realized by an array of weakly
coupled parallel one-dimensional "tubes" in a two-dimensional lattice which
permits free motion of atoms in an axial direction in the presence of a Zeeman
field, Rashba type spin orbit coupling (SOC), and an s-wave attractive
interaction, while the radial motion is tightly confined. We solve the
zero-temperature (T=0) Bogoliubov-de Gennes (BdG) equations for the quasi-1D
Fermi gas with the dispersion modified by tunneling between the tubes, and show
that the T=0 phase diagram hosts the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)
phase with non-zero center of mass momentum Cooper pairs for small values of
the SOC while for larger values of the SOC and high Zeeman fields the uniform
superfluid phase with zero center of mass momentum Cooper pairs has an
instability towards the topological uniform superfluid phase with Majorana
fermions at the tube ends. Also, we show that tuning the two-dimensional
optical lattice strength in this model allows one to explore the crossover
behaviors of the phases during the transition between the 3D and the 1D system
and in general the FFLO (for small SOC) and the topological uniform superfluid
phase (for large SOC) are favored as the system becomes more one-dimensional.
We also find evidence of the existence of a Zeeman tuned topological quantum
phase transition (TQPT) within the FFLO phase itself and for large values of
the Zeeman field and small SOC the TQPT gives rise to a topologically distinct
FFLO phase.


title: Graph Labeling with Distance Conditions and the Delta Squared Conjecture

abstract:
  We give bounds on the L(2,1)-labeling number of a simple graph in terms of
its order and its maximum degree. We also describe an infinite class of graphs
of which the elements have the highest L(2,1)-labeling numbers in terms of
their maximum degrees of any known infinite class of graphs.


title:
Learning from the past, predicting the statistics for the future,
  learning an evolving system

abstract:
  We bring the theory of rough paths to the study of non-parametric statistics
on streamed data. We discuss the problem of regression where the input variable
is a stream of information, and the dependent response is also (potentially) a
stream.
  A certain graded feature set of a stream, known in the rough path literature
as the signature, has a universality that allows formally, linear regression to
be used to characterise the functional relationship between independent
explanatory variables and the conditional distribution of the dependent
response.
  This approach, via linear regression on the signature of the stream, is
almost totally general, and yet it still allows explicit computation. The
grading allows truncation of the feature set and so leads to an efficient local
description for streams (rough paths). In the statistical context this method
offers potentially significant, even transformational dimension reduction.
  By way of illustration, our approach is applied to stationary time series
including the familiar AR model and ARCH model. In the numerical examples we
examined, our predictions achieve similar accuracy to the Gaussian Process (GP)
approach with much lower computational cost especially when the sample size is
large.


title:
Multi-Column Deep Neural Networks for Offline Handwritten Chinese
  Character Classification

abstract:
  Our Multi-Column Deep Neural Networks achieve best known recognition rates on
Chinese characters from the ICDAR 2011 and 2013 offline handwriting
competitions, approaching human performance.


title:
Designing Efficient Resource Sharing For Impatient Players Using Limited
  Monitoring

abstract:
  The problem of efficient sharing of a resource is nearly ubiquitous. Except
for pure public goods, each agent's use creates a negative externality; often
the negative externality is so strong that efficient sharing is impossible in
the short run. We show that, paradoxically, the impossibility of efficient
sharing in the short run enhances the possibility of efficient sharing in the
long run, even if outcomes depend stochastically on actions, monitoring is
limited and users are not patient. We base our analysis on the familiar
framework of repeated games with imperfect public monitoring, but we extend the
framework to view the monitoring structure as chosen by a designer who balances
the benefits and costs of more accurate observations and reports. Our
conclusions are much stronger than in the usual folk theorems: we do not
require a rich signal structure or patient users and provide an explicit online
construction of equilibrium strategies.


title:
A note on the effect of the cosmological constant on the bending of
  light

abstract:
  We take another look at the equations behind the description of light bending
in a Universe with a cosmological constant. We show that even within the impact
parameter entering into the photon's differential equation, and which is
defined here with exclusive reference to the beam of light as it bends around
the central mass, lies the contribution of the cosmological constant. The
latter is shown to enter in a novel way into the equation. When the latter is
solved our approach implies, beyond the first two orders in the mass-term and
the lowest-order in the cosmological constant, a slightly different expression
for the bending angle from what is previously found in the literature.


title:
On the Hardy constant of non-convex planar domains: the case of the
  quadrilateral

abstract:
  The Hardy constant of a simply connected domain $\Omega\subset\R^2$ is the
best constant for the inequality \[ \int_{\Omega}|\nabla u|^2dx \geq
c\int_{\Omega} \frac{u^2}{{\rm dist}(x,\partial\Omega)^2}\, dx \;, u\in
C^{\infty}_c(\Omega). \] After the work of Ancona where the universal lower
bound 1/16 was obtained, there has been a substantial interest on computing or
estimating the Hardy constant of planar domains. In this work we determine the
Hardy constant of an arbitrary quadrilateral in the plane. In particular we
show that the Hardy constant is the same as that of a certain infinite
sectorial region which has been studied by E.B. Davies.


title:
From regional pulse vaccination to global disease eradication: insights
  from a mathematical model of Poliomyelitis

abstract:
  Mass-vaccination campaigns are an important strategy in the global fight
against poliomyelitis and measles. The large-scale logistics required for these
mass immunisation campaigns magnifies the need for research into the
effectiveness and optimal deployment of pulse vaccination. In order to better
understand this control strategy, we propose a mathematical model accounting
for the disease dynamics in connected regions, incorporating seasonality,
environmental reservoirs and independent periodic pulse vaccination schedules
in each region. The effective reproduction number, $R_e$, is defined and proved
to be a global threshold for persistence of the disease. Analytical and
numerical calculations show the importance of synchronising the pulse
vaccinations in connected regions and the timing of the pulses with respect to
the pathogen circulation seasonality. Our results indicate that it may be
crucial for mass-vaccination programs, such as national immunisation days, to
be synchronised across different regions. In addition, simulations show that a
migration imbalance can increase $R_e$ and alter how pulse vaccination should
be optimally distributed among the patches, similar to results found with
constant-rate vaccination. Furthermore, contrary to the case of constant-rate
vaccination, the fraction of environmental transmission affects the value of
$R_e$ when pulse vaccination is present.


title: Non-linear Kaluza-Klein theory for dual fields

abstract:
  We present non-linear uplift ansaetze for all the bosonic degrees of freedom
and dual fields in the 7-sphere reduction of D=11 supergravity to maximal SO(8)
gauged supergravity and test them for the SO$(7)^{\pm}$ invariant solutions. In
particular, we complete the known ansaetze for the internal components of the
metric and 4-form flux by constructing a non-linear ansatz for the internal
components of the dual 7-form flux. Furthermore, we provide ansaetze for the
complete set of 56 vector fields, which are given by more general structures
than those available from standard Kaluza-Klein theory. The novel features
encountered here have no conventional geometric interpretation and provide a
new perspective on Kaluza-Klein theory. We study the recently found set of
generalised vielbein postulates and, for the 7-sphere compactification, we show
that they reduce to the E7(7) Cartan equation of maximal SO(8) gauged
supergravity in four dimensions. The significance of this framework for a
higher-dimensional understanding of the embedding tensor and other gauged
maximal supergravities is briefly discussed.


title: Structural thermokinetic modelling

abstract:
  Translating metabolic networks into dynamic models is difficult if kinetic
constants are unknown. Structural Kinetic Modelling (SKM) replaces reaction
elasticities by independent random numbers. Here I propose a variant that
accounts for reversible reactions and thermodynamics: in Structural
Thermokinetic Modelling (STM), correlated elasticities are computed from enzyme
saturation values and thermodynamic forces, which are physically independent.
STM relies on a dependency schema in which basic variables can be sampled,
fitted to data, or optimised, while all other variables are computed from them.
Probability distributions in the dependency schema define a model ensemble,
which leads to probabilistic predictions even if data are scarce. STM
highlights the importance of variabilities, dependencies and covariances of
biological variables. By choosing or sampling the basic variables, we can
convert metabolic networks into kinetic models with consistent reversible rate
laws. Metabolic control coefficients obtained from these models can tell us
about metabolic dynamics, including responses and optimal adaptations to
perturbations as well as enzyme synergies, metabolite correlations, and
metabolic fluctuations arising from chemical noise. By comparing model variants
with different network structures, fluxes, thermodynamic forces, regulation, or
types of rate laws, we can quantify the effects of these model features. To
showcase STM, I study metabolic control, metabolic fluctuations, and enzyme
synergies, and how they are shaped by thermodynamic forces. Thermodynamics can
be used to obtain more precise predictions of flux control, enzyme synergies,
correlated flux and metabolite variations, and of the emergence and propagation
of metabolic noise.


title:
Laurent biorthogonal polynomials, q-Narayana polynomials and domino
  tilings of the Aztec diamonds

abstract:
  A T\"oplitz determinant whose entries are described by a q-analogue of the
Narayana polynomials is evaluated by means of Laurent biorthogonal polynomials
which allow of a combinatorial interpretation in terms of Schr\"oder paths. As
an application, a new proof is given to the Aztec diamond theorem by Elkies,
Kuperberg, Larsen and Propp concerning domino tilings of the Aztec diamonds.
The proof is based on the correspondence with non-intersecting Schr\"oder paths
developed by Eu and Fu.


title:
The scaling limits of the Minimal Spanning Tree and Invasion Percolation
  in the plane

abstract:
  We prove that the Minimal Spanning Tree and the Invasion Percolation Tree on
a version of the triangular lattice in the complex plane have unique scaling
limits, which are invariant under rotations, scalings, and, in the case of the
MST, also under translations. However, they are not expected to be conformally
invariant. We also prove some geometric properties of the limiting MST. The
topology of convergence is the space of spanning trees introduced by Aizenman,
Burchard, Newman & Wilson (1999), and the proof relies on the existence and
conformal covariance of the scaling limit of the near-critical percolation
ensemble, established in our earlier works.


title: High-Accuracy Total Variation for Compressed Video Sensing

abstract:
  Numerous total variation (TV) regularizers, engaged in image restoration
problem, encode the gradients by means of simple $[-1,1]$ FIR filter. Despite
its low computational processing, this filter severely deviates signal's high
frequency components pertinent to edge/discontinuous information and cause
several deficiency issues known as texture and geometric loss. This paper
addresses this problem by proposing an alternative model to the TV
regularization problem via high order accuracy differential FIR filters to
preserve rapid transitions in signal recovery. A numerical encoding scheme is
designed to extend the TV model into multidimensional representation (tensorial
decomposition). We adopt this design to regulate the spatial and temporal
redundancy in compressed video sensing problem to jointly recover frames from
under-sampled measurements. We then seek the solution via alternating direction
methods of multipliers and find a unique solution to quadratic minimization
step with capability of handling different boundary conditions. The resulting
algorithm uses much lower sampling rate and highly outperforms alternative
state-of-the-art methods. This is evaluated both in terms of restoration
accuracy and visual quality of the recovered frames.


title:
On transitivity and (non)amenability of Aut(F_n) actions on group
  presentations

abstract:
  For a finitely generated group $G$ the Nielsen graph $N_n(G)$, $n\geq
\operatorname{rank}(G)$, describes the action of the group
$\operatorname{Aut}F_n$ of automorphisms of the free group $F_n$ on generating
$n$-tuples of G by elementary Nielsen moves. The question of (non)amenability
of Nielsen graphs is of particular interest in relation with the open question
about Property $(T)$ for $\operatorname{Aut}F_n$, $n\geq 4$. We prove
nonamenability of Nielsen graphs $N_n(G)$ for all $n\ge
\max\{2,\operatorname{rank}(G)\}$ when $G$ is indicable, and for $n$ big enough
when $G$ is elementary amenable. We give an explicit description of $N_d(G)$
for relatively free (in some variety) groups of rank $d$ and discuss their
connectedness and nonamenability. Examples considered include free
polynilpotent groups and free Burnside groups.


title: Pair Correlations in the Two-Dimensional Fermi Gas

abstract:
  We consider the two-dimensional Fermi gas at finite temperature with
attractive short-range interactions. Using the virial expansion, which provides
a controlled approach at high temperatures, we determine the spectral function
and contact for the normal state. Our calculated spectra are in qualitative
agreement with recent photoemission measurements [M. Feld et al., Nature 480,
75 (2011)], thus suggesting that the observed pairing gap is a feature of the
high-temperature gas rather than being evidence of a pseudogap regime just
above the superfluid transition temperature. We further argue that the strong
pair correlations result from the fact that the crossover to bosonic dimers
occurs at weaker interactions than previously assumed.


title: Asymmetric Mutualism in Two- and Three-Dimensional Range Expansions

abstract:
  Genetic drift at the frontiers of two-dimensional range expansions of
microorganisms can frustrate local cooperation between different genetic
variants, demixing the population into distinct sectors. In a biological
context, mutualistic or antagonistic interactions will typically be asymmetric
between variants. By taking into account both the asymmetry and the interaction
strength, we show that the much weaker demixing in three dimensions allows for
a mutualistic phase over a much wider range of asymmetric cooperative benefits,
with mutualism prevailing for any positive, symmetric benefit. We also
demonstrate that expansions with undulating fronts roughen dramatically at the
boundaries of the mutualistic phase, with severe consequences for the
population genetics along the transition lines.


title:
Robust, scalable Hong-Ou-Mandel manifolds in quantum optical ring
  resonators

abstract:
  Quantum Information Processing, from cryptography to computation, based upon
linear quantum optical circuit elements relies heavily on the ability offered
by the Hong-Ou-Mandel (HOM) Effect to route photons from separate input modes
into one of two common output modes. Specifically, the HOM Effect accomplishes
the path entanglement of two photons at a time such that no coincidences are
observed in the output modes of a system exhibiting the effect. In this paper,
we prove in principle that a significant increase in the robustness of the HOM
Effect can be accomplished in a scalable, readily manufactured nanophotonic
system comprised of two waveguides coupled, on chip, to a ring resonator. We
show that by operating such a device properly, one can conditionally bunch
coincident input photons in a way that is far more robust and controllable than
possible with an ordinary balanced beam splitter.


title:
Global existence of a weak solution of the incompressible Euler
  equations with helical symmetry and $L^p$ vorticity

abstract:
  We prove the global existence of a helical weak solution of the 3D Euler
equations, in full space, for an initial velocity with helical symmetry,
without swirl and whose initial vorticity is compactly supported in the axial
plane and belongs to $L^p$, for some $p>\frac{4}{3}$. This result is an
extension of the existence part of the work of B. Ettinger and E. Titi (SIAM J.
Math Anal. 41(2009) 269-296), who studied well-posedness of the Euler equations
with helical symmetry without swirl, with bounded initial vorticity, in a
helical pipe.


title:
Traffic analyzer for differentiating BitTorrent handshake failures from
  port-scans

abstract:
  This paper aims to improve the accuracy of port-scan detectors by analyzing
traffic of BitTorrent hosts and differentiating their respective BitTorrent
connection (attempts) from port-scans.
  It is shown that by looking at BitTorrent coordination traffic and modelling
port-scanning behavior the number of BitTorrent-related false positives can be
reduced by 80% without any loss of IDS accuracy.


title: Categorizing Influential Authors Using Penalty Areas

abstract:
  The concept of h-index has been proposed to easily assess a researcher's
performance with a single two-dimensional number. However, by using only this
single number, we lose significant information about the distribution of the
number of citations per article of an author's publication list. Two authors
with the same h-index may have totally different distributions of the number of
citations per article. One may have a very long "tail" in the citation curve,
i.e. he may have published a great number of articles, which did not receive
relatively many citations. Another researcher may have a short tail, i.e.
almost all his publications got a relatively large number of citations. In this
article, we study an author's citation curve and we define some areas appearing
in this curve. These areas are used to further evaluate authors' research
performance from quantitative and qualitative point of view. We call these
areas as "penalty" ones, since the greater they are, the more an author's
performance is penalized. Moreover, we use these areas to establish new metrics
aiming at categorizing researchers in two distinct categories: "influential"
ones vs. "mass producers".


title:
On the N=2 superconformal index and eigenfunctions of the elliptic RS
  model

abstract:
  We define an infinite sequence of superconformal indices, I_n, generalizing
the Schur index for N=2 theories. For theories of class S we then suggest a
recursive technique to completely determine I_n. The information encoded in the
sequence of indices is equivalent to the N=2 superconformal index depending on
the maximal set of fugacities. Mathematically, the procedure suggested in this
note provides a perturbative algorithm for computing a set of eigenfunctions of
the elliptic Ruijsenaars-Schneider model.


title: On the Classification of Homogeneous Hypersurfaces in Complex Space

abstract:
  We discuss a family $M_t^n$, with $n\ge 2$, $t>1$, of real hypersurfaces in a
complex affine $n$-dimensional quadric arising in connection with the
classification of homogeneous compact simply-connected real-analytic
hypersurfaces in ${\mathbb C}^n$ due to Morimoto and Nagano. To finalize their
classification, one needs to resolve the problem of the embeddability of
$M_t^n$ in ${\mathbb C}^n$ for $n=3,7$. We show that $M_t^7$ is not embeddable
in ${\mathbb C}^7$ for every $t$ and that $M_t^3$ is embeddable in ${\mathbb
C}^3$ for all $1<t<1+10^{-6}$. As a consequence of our analysis of a map
constructed by Ahern and Rudin, we also conjecture that the embeddability of
$M_t^3$ takes place for all\, $1<t<\sqrt{(2+\sqrt{2})/3}$.


title:
Triharmonic isometric immersions into a manifold of non-positively
  constant curvature

abstract:
  A triharmonic map is a critical point of the 3-energy in the space of smooth
maps between two Riemannian manifolds. We study a triharmonic isometric
immersion into a space form of non-positively constant curvature. We show that
if the domain is complete and both the 4-enegy and the L^4-norm of the tension
field are finite, then such an immersion is minimal.


title: The set of packing and covering densities of convex disks

abstract:
  For every convex disk $K$ (a convex compact subset of the plane, with
non-void interior), the packing density $\delta(K)$ and covering density
$\vartheta(K)$ form an ordered pair of real numbers, {\em i.e.}, a point in
${\mathbb R}^2$. The set $\Omega$ consisting of points assigned this way to all
convex disks is the subject of this article. A few known inequalities on
$\delta(K)$ and $\vartheta(K)$ jointly outline a relatively small convex
polygon $P$ that contains $\Omega$, while the exact shape of $\Omega$ remains a
mystery. Here we describe explicitly a leaf-shaped convex region $\Lambda$
contained in $\Omega$ and occupying a good portion of $P$. The sets $\Omega_T$
and $\Omega_L$ of translational packing and covering densities and lattice
packing and covering densities are defined similarly, restricting the allowed
arrangements of $K$ to translated copies or lattice arrangements, respectively.
Due to affine invariance of the translative and lattice density functions, the
sets $\Omega_T$ and $\Omega_L$ are compact. Furthermore, the sets $\Omega$,
$\Omega_T$ and $\Omega_L$ contain the subsets $\Omega^\star$, $\Omega_T^\star$
and $\Omega_L^\star$ respectively, corresponding to the centrally symmetric
convex disks $K$, and our leaf $\Lambda$ is contained in each of
$\Omega^\star$, $\Omega_T^\star$ and $\Omega_L^\star$.


title: Born-Infeld Monopoles and Instantons

abstract:
  We show that in certain non-Abelian Born-Infeld-Higgs theories there are
monopole solutions obeying Bogomol'nyi-like equations in the Prasad-Sommerfield
limit. We also discuss the existence of instanton solution in an SU(2)
Born-Infeld theory.


title:
Optical properties of charged quantum dots doped with a single magnetic
  impurity

abstract:
  We present a microscopic theory of the optical properties of self-assembled
quantum dots doped with a single magnetic manganese (Mn) impurity and
containing a controlled number of electrons. The single-particle electron and
heavy-hole electronic shells are described by two-dimensional harmonic
oscillators. The electron-electron, electron-hole Coulomb as well as the
short-range electron spin-Mn spin and hole spin-Mn spin contact exchange
interactions are included. The electronic states of the photo-excited
electron-hole-Mn complex and of the final electron-Mn complex are expanded in a
finite number of configurations and the full interacting Hamiltonian is
diagonalized numerically. The emission spectrum is predicted as a function of
photon energy for a given number of electrons and different number of confined
electronic quantum dot shells. We show how emission spectra allow to identify
the number of electronic shells, the number of electrons populating these
shells and, most importantly, their spin. We show that electrons not
interacting directly with the spin of Mn ion do so via electron-electron
interactions. This indirect interaction is a strong effect even when Mn
impurity is away from the quantum dot center.


title: Irreducibility of induced modules for general linear supergroups

abstract:
  In this note we determine when is an induced module H^0_G(\lambda),
corresponding to a dominant integral highest weight \lambda of the general
linear supergroup G=GL(m|n) irreducible. Using the contravariant duality given
by the supertrace we obtain a characterization of irreducibility of Weyl
modules V(\lambda). This extends the result of Kac who proved that, for ground
fields of characteristic zero, V(\lambda) is irreducible if and only if \lambda
is typical.


title: CP violation in bipair neutrino mixing

abstract:
  There are experimentally determined two best-fit points for the atmospheric
neutrino mixing angle $\theta_{23}$: $\sin^2 \theta_{23} = 0.413$ (case A) and
$\sin^2 \theta_{23} = 0.594$ (case B). In the bipair neutrino mixing scheme, we
predict $\sin^2\theta_{23} = \sqrt{2}-1$ (case 1) to be consistent with the
case A and $\sin^2\theta_{23} = 2-\sqrt{2}$ (case 2) to be consistent with the
case B. If the case B is realized in nature, the bipair neutrino mixing
provides a unique neutrino model consistent with the observation $\sin^2
\theta_{23} = 0.594$. However, the reactor neutrino mixing angle $\theta_{13}$
is predicted to be $\sin^2\theta_{13} = 0$, which is inconsistent with the
observation. We propose a new modification scheme to yield $\sin^2\theta_{13}
\neq 0$ utilizing the charged lepton contribution and study its effect on both
of CP-violating Dirac and Majorana phases, which is numerically estimated. It
is found that there appear striking differences between the case 1 and the case
2 in their phase structure.


title: Classification of connected Hopf algebras of dimension $p^3$ I

abstract:
  Let $p$ be a prime, $k$ be an algebraically closed field of characteristic
$p$. In this paper, we provide the classification of connected Hopf algebras of
dimension $p^3$, except the case when the primitive space of the Hopf algebra
is two dimensional and abelian. Each isomorphism class is presented by
generators $x, y, z$ with relations and Hopf algebra structures. Let $\mu$ be
the multiplicative group of $(p^2+p-1)$-th roots of unity. When the primitive
space is one-dimensional and $p$ is odd, there is an infinite family of
isomorphism classes, which is naturally parameterized by $A_{k}^1/\mu$.


title: Waveform Digitizing for LaBr$_3$/NaI Phoswich Detector

abstract:
  The detection efficiency of phoswich detector starts to decrease when Compton
scattering becomes significant. Events with energy deposit in both
scintillators, if not rejected, are not useful for spectral analysis as the
full energy of the incident photon cannot be reconstructed with conventional
readout. We show that once the system response is carefully calibrated, the
full energy of those double deposit events can be reconstructed using a
waveform digitizer as the readout. Our experiment suggests that the efficiency
of photopeak at 662 keV can be increased by a factor of 2 given our
LaBr$_3$/NaI phoswich detector.


title: Direct solutions for normal depths in curved irrigation canals

abstract:
  The normal depth is an important hydraulic element for canal design,
operation and management. Curved irrigation canals including parabola, U-shaped
and catenary canals have excellent hydraulic performance and strong ability of
anti-frost heave, while the normal depths in the governing equations of the
current common methods have no explicit analytical solution. They are only
indirect methods by using trial procedures, numerical methods, and graphical
tools. This study presents new direct formulas for normal depth in curved
irrigation canals by applying for Marquardt method. The maximum relative error
of the proposed formulas is less than 1% within the practice range by
comparative analysis, and they are simple and convenient for manual
calculations. The results may provide the reliable theoretical basis and useful
reference for the design and operation management of irrigation canals.


title:
Direct numerical simulations of rigid body dispersions. I.
  Mobility/Friction tensors of assemblies of spheres

abstract:
  An improved formulation of the Smoothed Profile method is introduced to
perform direct numerical simulations of arbitrary rigid body dispersions in a
Newtonian host solvent. Previous implementations of the method were restricted
to spherical particles, severely limiting the types of systems that could be
studied. The validity of the method is carefully examined by computing the
friction/mobility tensors for a wide variety of geometries and comparing them
to reference values obtained from accurate solutions to the Stokes-Equation.


title: MHD Simulation of a Disk Subjected to Lense-Thirring Precession

abstract:
  When matter orbits around a central mass obliquely with respect to the mass's
spin axis, the Lense-Thirring effect causes it to precess at a rate declining
sharply with radius. Ever since the work of Bardeen & Petterson (1975), it has
been expected that when a fluid fills an orbiting disk, the orbital angular
momentum at small radii should then align with the mass's spin. Nearly all
previous work has studied this alignment under the assumption that a
phenomenological "viscosity" isotropically degrades fluid shears in accretion
disks, even though it is now understood that internal stress in flat disks is
due to anisotropic MHD turbulence. In this paper we report a pair of matched
simulations, one in MHD and one in pure (non-viscous) HD in order to clarify
the specific mechanisms of alignment. As in the previous work, we find that
disk warps induce radial flows that mix angular momentum of different
orientation; however, we also show that the speeds of these flows are
generically transonic and are only very weakly influenced by internal stresses
other than pressure. In particular, MHD turbulence does not act in a manner
consistent with an isotropic viscosity. When MHD effects are present, the disk
aligns, first at small radii and then at large; alignment is only partial in
the HD case. We identify the specific angular momentum transport mechanisms
causing alignment and show how MHD effects permit them to operate more
efficiently. Lastly, we relate the speed at which an alignment front propagates
outward (in the MHD case) to the rate at which Lense-Thirring torques deliver
angular momentum at smaller radii.


title: High-Symmetry Polarization Domains in Low-Symmetry Ferroelectrics

abstract:
  We present experimental evidence for hexagonal domain faceting in the
ferroelectric polymer PVDF-TrFE films having the lower orthorhombic
crystallographic symmetry. This effect can arise from purely electrostatic
depolarizing forces. We show that in contrast to magnetic bubble shape domains
where such type of deformation instability has a predominantly elliptical
character, the emergence of more symmetrical circular harmonics is favored in
ferroelectrics with high dielectric constant.


title:
Minimal extension of General Relativity: alternative gravity model with
  non-minimal coupling between matter and curvature

abstract:
  We examine an extension of General Relativity with an explicit non-minimal
coupling between matter and curvature. The purpose of this work is to present
an overview of the implications of the latter to various contexts, ranging from
astrophysical matter distributions to a cosmological setting. Various results
are discussed, including the impact of this non-minimal coupling on the choice
of Lagrangian density, on a mechanism to mimic galactic and cluster dark
matter, on the possibility of accounting for the accelerated expansion of the
Universe, energy density fluctuations and modifications to post-inflationary
reheating. The equivalence between a model exhibiting a non-minimal coupling
and multi-scalar-theories is also discussed.


title: On the supersymmetrization of inflation in f(R) gravity

abstract:
  An N=1 Poincare supergravity action, suitable for describing the Starobinsky
inflation, is proposed. It extends f(R) gravity to supergravity in its
old-minimal version. The action is parametrized by a single holomorphic
potential and a single non-holomorphic potential, and can be dualized into the
standard matter-coupled supergravity action, with the "matter" given by two
chiral superfields. The action extends the earlier proposals for embedding the
Starobinsky inflation into supergravity, and can be further generalized to
include quantum corrections to the inflation. Our approach assumes the
gravitational origin of inflaton and quintessence in the context of
supergravity, by using a single chiral scalar curvature superfield.


title: Bottom-up Engineering of Diamond Nanostructures

abstract:
  Engineering nanostructures from the bottom up enables the creation of
carefully engineered complex structures that are not accessible via top down
fabrication techniques, in particular, complex periodic structures for
applications in photonics and sensing. In this work, we propose and demonstrate
a bottom up approach that can be adopted and utilized to controllably build
diamond nanostructures. A realization of periodic structures and optical
wave-guiding is achieved by growing nanoscale single crystal diamond through a
defined pattern.


title: Fixed points and homology of superelliptic Jacobians

abstract:
  Let $\eta: C_{f,N}\to \mathbb{P}^1$ be a cyclic cover of $\mathbb{P}^1$ of
degree $N$ which is totally and tamely ramified for all the ramification
points. We determine the group of fixed points of the cyclic group
$\mathbf{mu}_N\cong \mathbb{Z}/N\mathbb{Z}$ acting on the Jacobian
$J_N:=\Jac(C_{f,N})$. For each $\ell$ distinct from the characteristic of the
base field, the Tate module $T_\ell J_N$ is shown to be a free module over the
ring $\mathbb{Z}_\ell[T]/(\sum_{i=0}^{N-1}T^i)$. We also calculate the degree
of the induced polarization on the new part $J_N^{new}$ of the Jacobian.


title: A new kind of complexity

abstract:
  A new class of functions is presented. The structure of the algorithm,
particularly the selection criteria (branching), is used to define the
fundamental property of the new class. The most interesting property of the new
functions is that instances are easy to compute but if input to the function is
vague the description of a function is exponentially complex. This property
puts a new light on randomness especially on the random oracle model with a
couple of practical examples of random oracle implementation. Consequently,
there is a new interesting viewpoint on computational complexity in general.


title: Correlated charge transport in bilinear tunnel junction arrays

abstract:
  We study theoretically the nature of correlations in space and time of the
current in a one-dimensional bilinear array of tunnel junctions in the normal
conduction limit, using the kinetic Monte Carlo (KMC) method. The bilinear
array consists of two parallel rows of tunnel junctions, capacitively coupled
in a ladder configuration. The electrostatic potential landscape and the
charge-charge interaction length both depend on the circuit capacitances, which
in turn influence transport and charge correlations in the array. We observe
the formation of stationary charge states when only one rail is voltage biased.
When a symmetric bias is applied to both rails, the site at which the positive
and negative charge carriers recombine can drift throughout the array. We also
calculate charge densities and auto- and cross-correlation functions.


title:
Recent progress in perpendicularly magnetized Mn-based binary alloy
  films

abstract:
  In this article, we review the recent progress in growth, structural
characterization, magnetic properties and related spintronic devices of
tetragonal MnxGa and MnxAl thin films with perpendicular magnetic anisotropy.
In the first part of this review, we present a brief introduction to the
demands for perpendicularly magnetized materials in spintronics, magnetic
recording and permanent magnets applications, and the most promising candidates
of tetragonal MnxGa and MnxAl with strong perpendicular anisotropy. Then, in
the second and third parts, we focus on the recent progress of perpendicularly
magnetized MnxGa and MnxAl, respectively, including their lattice structures,
bulk synthesis, epitaxial growth, structural chracterizations, magnetic and
other spin-dependent properties, and spintronic devices like magnetic tunneling
junctions, spin valves and spin injector into semiconductors. Finally, we give
a summary and a perspective of these perpendicularly magnetized Mn-based binary
alloy films for future applications.


title: Macroscopic quantum behaviour of periodic quantum systems

abstract:
  In this paper we introduce a simple procedure for computing the macroscopic
quantum behaviour of periodic quantum systems in the high energy regime. The
macroscopic quantum coherence is ascribed to a one-particle state, not to a
condensate of a many-particle system; and we are referring to a system of high
energy but with few degrees of freedom. We show that, in the first order of
approximation, the quantum probability distributions converge to its classical
counterparts in a clear fashion, and that the interference effects are strongly
suppressed. The harmonic oscillator provides a testing ground for these ideas
and yields excellent results.


title: Zappa-Sz\'ep products of semigroups and their C*-algebras

abstract:
  Zappa-Sz\'ep products of semigroups encompass both the self-similar group
actions of Nekrashevych and the quasi-lattice-ordered groups of Nica. We use
Li's construction of semigroup $C^*$-algebras to associate a $C^*$-algebra to
Zappa-Sz\'ep products and give an explicit presentation of the algebra. We then
define a quotient $C^*$-algebra that generalises the Cuntz-Pimsner algebras for
self-similar actions. We indicate how known examples, previously viewed as
distinct classes, fit into our unifying framework. We specifically discuss the
Baumslag-Solitar groups, the binary adding machine, the semigroup
$\mathbb{N}\rtimes\mathbb{N}^\times$, and the $ax+b$-semigroup
$\mathbb{Z}\rtimes\mathbb{Z}^\times$.


title: Testing leptoquark models in $\bar B \to D^{(*)} \tau \bar\nu$

abstract:
  We study potential New Physics effects in the $\bar B \to D^{(*)} \tau
\bar\nu$ decays. As a particular example of New Physics models we consider the
class of leptoquark models and put the constraints on the leptoquark couplings
using the recently measured ratios $R(D^{(*)})=BR(\bar B \to D^{(*)} \tau
\bar\nu)/BR(\bar B \to D^{(*)} \mu \bar\nu)$. For consistency, some of the
constraints are compared with the ones coming from the current experimental
bound on $BR(B \to X_s \nu \bar\nu)$. In order to discriminate various New
Physics scenarios, we examine the correlations between different observables
that can be measured in future.


title:
Unmixing Incoherent Structures of Big Data by Randomized or Greedy
  Decomposition

abstract:
  Learning big data by matrix decomposition always suffers from expensive
computation, mixing of complicated structures and noise. In this paper, we
study more adaptive models and efficient algorithms that decompose a data
matrix as the sum of semantic components with incoherent structures. We firstly
introduce "GO decomposition (GoDec)", an alternating projection method
estimating the low-rank part $L$ and the sparse part $S$ from data matrix
$X=L+S+G$ corrupted by noise $G$. Two acceleration strategies are proposed to
obtain scalable unmixing algorithm on big data: 1) Bilateral random projection
(BRP) is developed to speed up the update of $L$ in GoDec by a closed-form
built from left and right random projections of $X-S$ in lower dimensions; 2)
Greedy bilateral (GreB) paradigm updates the left and right factors of $L$ in a
mutually adaptive and greedy incremental manner, and achieve significant
improvement in both time and sample complexities. Then we proposes three
nontrivial variants of GoDec that generalizes GoDec to more general data type
and whose fast algorithms can be derived from the two strategies......


title:
Fundamental Limits of HRR Profiling and Velocity Compensation For
  Stepped-Frequency Waveforms

abstract:
  The stepped-frequency (SF) waveform is an effective way to achieve high range
resolution (HRR) in modern radars. In this paper, we determine some fundamental
limits of SF waveforms on ambiguity, stability and accuracy of stable targets
profiling, and velocity compensation accuracy of moving targets. The
investigation shows that via using the information contained in both phase and
envelop of the echo signal, the radar can achieve HRR profiles without
ambiguity under a looser criterion, and can compensate the range shift caused
by targets' radial velocity. The results of this paper can help the SF waveform
design and the processing algorithm development for HRR profiling and velocity
compensation.


title: A proof of extension conjecture

abstract:
  Extension conjecture states that if a simple module over an artin algebra has
nonzero first self-extension group then it has nonzero i-th self-extension
group for infinitely many positive integers i. It is shown by recollement of
triangulated categories and differential graded homological algebra approach
that extension conjecture is true for finite-dimensional elementary algebras
over a field, particularly, for finite-dimensional algebras over an
algebraically closed field. Moreover, bimodule approach is introduced to strong
no loop conjecture, which provides two new proofs of Igusa-Liu-Paquette
theorem.


title:
Quantifying 'causality' in complex systems: Understanding Transfer
  Entropy

abstract:
  'Causal' direction is of great importance when dealing with complex systems.
Often big volumes of data in the form of time series are available and it is
important to develop methods that can inform about possible causal connections
between the different observables. Here we investigate the ability of the
Transfer Entropy measure to identify causal relations embedded in emergent
coherent correlations. We do this by firstly applying Transfer Entropy to an
amended Ising model. In addition we use a simple Random Transition model to
test the reliability of Transfer Entropy as a measure of `causal' direction in
the presence of stochastic fluctuations. In particular we systematically study
the effect of the finite size of data sets.


title: Temperature Dependence of Spin Hall Angle of Palladium

abstract:
  In this study, the temperature dependence of the spin Hall angle of palladium
(Pd) was experimentally investigated by spin pumping. A Ni80Fe20/Pd bilayer
thin film was prepared, and a pure spin current was dynamically injected into
the Pd layer. This caused the conversion of the spin current to a charge
current owing to the inverse spin Hall effect. It was found that the spin Hall
angle varies as a function of temperature, whereby the value of the spin Hall
angle increases to ca. 0.02 at 123 K.


title: Valley polarized transport in strained graphene based Corbino disc

abstract:
  We study analytically and numerically the magnetotransport of strained
graphene in a Corbino geometry gating in the presence of an external
perpendicular magnetic field. The conductance of the Corbino disc of deformed
graphene with a uniaxial and an inhomogeneous strain is calculated by using the
Landauer-B\"{u}ttiker method. We show that the oscillation period of the
conductance as a function of the magnetic flux depends on uniaxial strain and
the conductance sharply drops along the direction of graphene stretching. The
conductance amplitude, on the other hand, can be manipulated by induced
pseudomagnetic flux. A valley polarized regime, caused by the inhomogeneous
strain, is obtained and in addition we find a wide energy interval in which the
system is fully valley polarized.


title:
Bound states of the one-dimensional Dirac equation for scalar and vector
  double square-well potentials

abstract:
  We have analytically studied bound states of the one-dimensional Dirac
equation for scalar and vector double square-well potentials (DSPs), by using
the transfer-matrix method. Detailed numerical calculations of the eigenvalue,
wave function and density probability have been performed for the three cases:
(1) vector DSP only, (2) scalar DSP only, and (3) scalar and vector DSPs with
equal magnitudes. We discuss the difference and similarity among results of the
cases (1)-(3) in the Dirac equation and that in the Schr\"{o}dinger equation.
Motion of a wave packet is calculated for a study on quantum tunneling through
the central barrier in the DSP.


title:
A Study on Unsupervised Dictionary Learning and Feature Encoding for
  Action Classification

abstract:
  Many efforts have been devoted to develop alternative methods to traditional
vector quantization in image domain such as sparse coding and soft-assignment.
These approaches can be split into a dictionary learning phase and a feature
encoding phase which are often closely connected. In this paper, we investigate
the effects of these phases by separating them for video-based action
classification. We compare several dictionary learning methods and feature
encoding schemes through extensive experiments on KTH and HMDB51 datasets.
Experimental results indicate that sparse coding performs consistently better
than the other encoding methods in large complex dataset (i.e., HMDB51), and it
is robust to different dictionaries. For small simple dataset (i.e., KTH) with
less variation, however, all the encoding strategies perform competitively. In
addition, we note that the strength of sophisticated encoding approaches comes
not from their corresponding dictionaries but the encoding mechanisms, and we
can just use randomly selected exemplars as dictionaries for video-based action
classification.


title:
Microscopic mechanism for asymmetric charge distribution in Rashba-type
  surface states and the origin of the the energy splitting scale

abstract:
  Microscopic mechanism for the Rashba-type band splitting is examined in
detail. We show how asymmetric charge distribution is formed when local orbital
angular momentum (OAM) and crystal momentum get interlocked due to surface
effects. An electrostatic energy term in the Hamiltonian appears when such OAM
and crystal momentum dependent asymmetric charge distribution is placed in an
electric field produced from an inversion symmetry breaking (ISB). Analysis by
using an effective Hamiltonian shows that, as the atomic spin-orbit coupling
(SOC) strength increases from weak to strong, originally OAM-quenched states
evolve into well-defined chiral OAM states and then to total angular momentum
J-states. In addition, the energy scale of the band splitting changes from
atomic SOC energy to electrostatic energy. To confirm the validity of the
model, we study OAM and spin structures of Au(111) system by using an effective
Hamiltonian for the d-orbitals case. As for strong SOC regime, we choose
Bi2Te2Se as a prototype system. We performed circular dichroism angle resolved
photoemission spectroscopy experiments as well as first-principles
calculations. We find that the effective model can explain various aspects of
spin and OAM structures of the system.


title: Phenomenology of Space-time Imperfection I: Nonlocal Defects

abstract:
  If space-time is emergent from a fundamentally non-geometric theory it will
generically be left with defects. Such defects need not respect the locality
that emerges with the background. Here, we develop a phenomenological model
that parameterizes the effects of nonlocal defects on the propagation of
particles. In this model, Lorentz-invariance is preserved on the average. We
derive constraints on the density of defects from various experiments.


title: Secure communication with choice of measurement

abstract:
  It has been found that the signal can be encoded in the choice of the
measurement basis of one of the communicating parties, while the outcomes of
the measurement are irrelevant for the communication and therefore may be
discarded. The proposed protocol was novel and interesting, but it wasn't
secure for communication. The eavesdropper can obtain the information without
being detected. We utilize the outcomes of the measurement to propose a secure
communication protocol. And the error correction code is used to increase the
fault tolerance in the noise.


title:
Penguin Pollution in $B\to J/\psi V$ Decays and Impact on the Extraction
  of the $B_s-\bar B_s$ mixing phase

abstract:
  We formulate the most-general time-dependent decay distributions of $B_s\to
J/\psi (\to l^+l^-) \phi(\to K^+K^-)$ in which the direct CP violation is
explicitly incorporated. We then investigate the $B \to J/\psi V$ decays in the
perturbative QCD approach where $V$ is a light vector meson. Apart from the
leading-order factorizable contributions, we also take into account various QCD
corrections and the hard-spectator diagrams. With the inclusion of these
sizable corrections, our theoretical results for CP-averaged branching ratios,
polarization fractions, CP-violating asymmetries, and relative phases are in
good consistency with the available data. Based on the global agreement, we
further explore the penguin contributions and point out that the $\phi_s$
extracted from $B_s\to J/\psi \phi$ can be shifted away by ${\cal O}(10^{-3})$.


title: Phenomenology of Space-time Imperfection II: Local Defects

abstract:
  We propose a phenomenological model for the scattering of particles on
space-time defects in a treatment that maintains Lorentz-invariance on the
average. The local defects considered here cause a stochastic violation of
momentum conservation. The scattering probability is parameterized in the
density of defects and the distribution of the momentum that a particle can
obtain when scattering on the defect. We identify the most promising observable
consequences and derive constraints from existing data.


title: The expansion of massive young star clusters - observation meets theory

abstract:
  Most stars form as part of a star cluster. The most massive clusters in the
Milky Way exist in two groups - loose and compact clusters - with significantly
different sizes at the end of the star formation process. After their formation
both types of clusters expand up to a factor 10-20 within the first 20 Myr. Gas
expulsion at the end of the star formation process is usually regarded as only
possible process that can lead to such an expansion.We investigate the effect
of gas expulsion by a direct comparison between numerical models and observed
clusters concentrating on clusters with masses >10^3 M(sun). For these clusters
the initial conditions before gas expulsion, the characteristic cluster
development, its dependence on cluster mass, and the star formation efficiency
(SFE) are investigated. We perform N-body simulations of the cluster expansion
process after gas expulsion and compare the results with observations. We find
that the expansion processes of the observed loose and compact massive clusters
are driven by completely different physical processes. As expected the
expansion of loose massive clusters is largely driven by the gas loss due to
the low SFE of ~30%. One new revelation is that all the observed massive
clusters of this group seem to have a very similar size of 1-3 pc at the onset
of expansion. It is demonstrated that compact clusters have a much higher
effective SFE of 60-70% and are as a result much less affected by gas
expulsion. Their expansion is mainly driven by stellar ejections caused by
interactions between the cluster members. The reason why ejections are so
efficient in driving cluster expansion is that they occur dominantly from the
cluster centre and over an extended period of time. Thus during the first 10
Myr the internal dynamics of loose and compact clusters differ fundamentally.


title:
Band Codes for Energy-Efficient Network Coding with Application to P2P
  Mobile Streaming

abstract:
  A key problem in random network coding (NC) lies in the complexity and energy
consumption associated with the packet decoding processes, which hinder its
application in mobile environments. Controlling and hence limiting such factors
has always been an important but elusive research goal, since the packet degree
distribution, which is the main factor driving the complexity, is altered in a
non-deterministic way by the random recombinations at the network nodes. In
this paper we tackle this problem proposing Band Codes (BC), a novel class of
network codes specifically designed to preserve the packet degree distribution
during packet encoding, ecombination and decoding. BC are random codes over
GF(2) that exhibit low decoding complexity, feature limited and controlled
degree distribution by construction, and hence allow to effectively apply NC
even in energy-constrained scenarios. In particular, in this paper we motivate
and describe our new design and provide a thorough analysis of its performance.
We provide numerical simulations of the performance of BC in order to validate
the analysis and assess the overhead of BC with respect to a onventional NC
scheme. Moreover, peer-to-peer media streaming experiments with a random-push
protocol show that BC reduce the decoding complexity by a factor of two, to a
point where NC-based mobile streaming to mobile devices becomes practically
feasible.


title: Properties of N=90 Isotones within the Mean Field Perspective

abstract:
  In recent years, the N=90 isotones have been investigated to a large extent
in relation to studies of quantum phase transitions. In this paper, we use the
mean field approach with pairing-deformation self consistent Total Routhian
Surface (TRS) calculations to study the N=90 isotones and neigh- bouring
nuclei. The important probes, such as moments of inertia, quadrupole moments,
the energy ratio of E(4+1)/E(2+1), octupole and hexadecapole degrees of freedom
are considered and the cal- culated results are compared with the available
experimental data. From a microscopic point of view, the N=90 isotones
characterize the onset of the deformed region and are very well described by
mean field calculations. The results are compared with those from other studies
in beyond mean-field approximations. Shape coexistence phenomena in the region
of interest are discussed.


title: Product formulas in functional calculi for sectorial operators

abstract:
  We study the product formula $(fg)(A) = f(A)g(A)$ in the framework of
(unbounded) functional calculus of sectorial operators $A$. We give an abstract
result, and, as corollaries, we obtain new product formulas for the holomorphic
functional calculus, an extended Stieltjes functional calculus and an extended
Hille-Phillips functional calculus. Our results generalise previous work of
Hirsch, Martinez and Sanz, and Schilling.


title: Continuity properties of the lower spectral radius

abstract:
  The lower spectral radius, or joint spectral subradius, of a set of real $d
\times d$ matrices is defined to be the smallest possible exponential growth
rate of long products of matrices drawn from that set. The lower spectral
radius arises naturally in connection with a number of topics including
combinatorics on words, the stability of linear inclusions in control theory,
and the study of random Cantor sets. In this article we apply some ideas
originating in the study of dominated splittings of linear cocycles over a
dynamical system to characterise the points of continuity of the lower spectral
radius on the set of all compact sets of invertible $d \times d$ matrices. As
an application we exhibit open sets of pairs of $2 \times 2$ matrices within
which the analogue of the Lagarias-Wang finiteness property for the lower
spectral radius fails on a residual set, and discuss some implications of this
result for the computation of the lower spectral radius.


title: On the eigenvalues of certain number-theoretic matrices

abstract:
  In this paper we study the structure and give bounds for the eigenvalues of
the $n\times n$ matrix, which $ij$ entry is $(i,j)^\alpha[i,j]^\beta$, where
$\alpha,\beta\in\Rset$, $(i,j)$ is the greatest common divisor of $i$ and $j$
and $[i,j]$ is the least common multiple of $i$ and $j$. Currently only
$O$-estimates for the greatest eigenvalue of this matrix can be found in the
literature, and the asymptotic behaviour of the greatest and smallest
eigenvalue is known in case when $\alpha=\beta$.


title:
An experimental study of regime transitions in a differentially heated
  baroclinic annulus with flat and sloping bottom topographies

abstract:
  A series of laboratory experiments has been carried out in a thermally driven
rotating annulus to study the onset of baroclinic instability, using horizontal
and uniformly sloping bottom topographies. Different wave flow regimes have
been identified and their phase boundaries -- expressed in terms of appropriate
non-dimensional parameters -- have been compared to the recent numerical
results of \citet{thomas_slope}. In the flat bottom case, the numerically
predicted alignment of the boundary between the axisymmetric and the regular
wave flow regime was found to be consistent with the experimental results.
However, once the sloping bottom end wall was introduced, the detected
behaviour was qualitatively different from that of the simulations. This
disagreement is thought to be the consequence of nonlinear wave-wave
interactions that could not be resolved in the framework of the numerical
study. This argument is supported by the observed development of interference
vacillation in the runs with sloping bottom, a mixed flow state in which
baroclinic wave modes exhibiting different drift rates and amplitudes can
co-exist.


title:
Exceptionally Fast Water Desalination at Complete Salt Rejection by
  Pristine Graphyne Monolayers

abstract:
  Desalination that produces clean freshwater from seawater holds the promise
to solve the global water shortage for drinking, agriculture and industry.
However, conventional desalination technologies such as reverse osmosis and
thermal distillation involve large amounts of energy consumption, and the
semipermeable membranes widely used in reverse osmosis face the challenge to
provide a high throughput at high salt rejection. Here we find by comprehensive
molecular dynamics simulations and first principles modeling that, pristine
graphyne, one of the graphene like one-atom-thick carbon allotropes, can
achieve 100% rejection of nearly all ions in seawater including Na+, Cl-, Mg2+,
K+ and Ca2+, at an exceptionally high water permeability about two orders of
magnitude higher than those for commercial state-of-the-art reverse osmosis
membranes at a salt rejection of ~98.5%. This complete ion rejection by
graphyne, independent of the salt concentration and the operating pressure, is
revealed to be originated from the significantly higher energy barriers for
ions than that for water. This intrinsic specialty of graphyne should provide a
new possibility for the efforts to alleviate the global shortage of freshwater
and other environmental problems.


title:
Probing the statistical decay and alpha-clustering effects in 12c+12c
  and 14n+10b reactions

abstract:
  An experimental campaign has been undertaken at INFN Laboratori Nazionali di
Legnaro, Italy, in order to progress in our understanding of the statistical
properties of light nuclei at excitation energies above particle emission
threshold, by measuring exclusive data from fusion-evaporation reactions. A
first reaction 12C+12C at 7.9 AMeV beam energy has been measured, using the
GARFIELD+Ring Counter experimental setup. Fusion-evaporation events have been
exclusively selected. The comparison to a dedicated Hauser-Feshbach calculation
allows us to give constraints on the nuclear level density at high excitation
energy for light systems ranging from C up to Mg. Out-of-equilibrium emission
has been evidenced and attributed both to entrance channel effects favoured by
the cluster nature of reaction partners and, in more dissipative events, to the
persistence of cluster correlations well above the 24Mg threshold for 6 alphas
decay. The 24Mg compound nucleus has been studied with a new measurement 14N +
10B at 5.7 AMeV. The comparison between the two datasets would allow us to
further constrain the level density of light nuclei. Deviations from a
statistical behaviour can be analyzed to get information on nuclear clustering.


title: Multiple Exponential and Character Sums with Monomials

abstract:
  We obtain new bounds of multivariate exponential sums with monomials, when
the variables run over rather short intervals. Furthermore, we use the same
method to derive estimates on similar sums with multiplicative characters to
which previously known methods do not apply. In particular, in the
multiplicative characters modulo a prime $p$ we break the barrier of $p^{1/4}$
for ranges of individual variables.


title:
Variational Approach to Necessary and Sufficient Stability Conditions
  for Inviscid Shear Flow

abstract:
  A necessary and sufficient condition for linear stability of inviscid
parallel shear flow is formulated by a novel variational method, where the
velocity profile is assumed to be monotonic and analytic. Unstable eigenvalues
of the Rayleigh equation are shown to be associated with positive eigenvalues
of a certain selfadjoint operator. The stability is therefore simply determined
by maximizing a quadratic form, which is theoretically and numerically more
tractable than directly solving the Rayleigh equation. This variational
approach is based on the Hamiltonian nature of the inviscid fluid and will be
applicable to other hydrodynamic stability problems.


title:
Tagging Scientific Publications using Wikipedia and Natural Language
  Processing Tools. Comparison on the ArXiv Dataset

abstract:
  In this work, we compare two simple methods of tagging scientific
publications with labels reflecting their content. As a first source of labels
Wikipedia is employed, second label set is constructed from the noun phrases
occurring in the analyzed corpus. We examine the statistical properties and the
effectiveness of both approaches on the dataset consisting of abstracts from
0.7 million of scientific documents deposited in the ArXiv preprint collection.
We believe that obtained tags can be later on applied as useful document
features in various machine learning tasks (document similarity, clustering,
topic modelling, etc.).


title:
The effect of common-envelope evolution on the visible population of
  post-common-envelope binaries

abstract:
  Context. An important ingredient in binary evolution is the common-envelope
(CE) phase. Although this phase is believed to be responsible for the formation
of many close binaries, the process is not well understood. Aims. We
investigate the characteristics of the population of post-common-envelope
binaries (PCEB). As the evolution of these binaries and their stellar
components are relatively simple, this population can be directly used to
constraint CE evolution. Methods. We use the binary population synthesis code
SeBa to simulate the current-day population of PCEBs in the Galaxy. We
incorporate the selection effects in our model that are inherent to the general
PCEB population and that are specific to the SDSS survey, which enables a
direct comparison for the first time between the synthetic and observed
population of visible PCEBs. Results. We find that selection effects do not
play a significant role on the period distribution of visible PCEBs. To explain
the observed dearth of long-period systems, the {\alpha}-CE efficiency of the
main evolutionary channel must be low. In the main channel, the CE is initiated
by a red giant as it fills its Roche lobe in a dynamically unstable way. Other
evolutionary paths cannot be constrained more. Additionally our model
reproduces well the observed space density, the fraction of visible PCEBs
amongst white dwarf (WD)- main sequence (MS) binaries, and the WD mass versus
MS mass distribution, but overestimates the fraction of PCEBs with helium WD
companions.


title: Boundedness of Pseudodifferential Operators on Banach Function Spaces

abstract:
  We show that if the Hardy-Littlewood maximal operator is bounded on a
separable Banach function space $X(\mathbb{R}^n)$ and on its associate space
$X'(\mathbb{R}^n)$, then a pseudodifferential operator $\operatorname{Op}(a)$
is bounded on $X(\mathbb{R}^n)$ whenever the symbol $a$ belongs to the
H\"ormander class $S_{\rho,\delta}^{n(\rho-1)}$ with $0<\rho\le 1$,
$0\le\delta<1$ or to the the Miyachi class
$S_{\rho,\delta}^{n(\rho-1)}(\varkappa,n)$ with $0\le\delta\le\rho\le 1$,
$0\le\delta<1$, and $\varkappa>0$. This result is applied to the case of
variable Lebesgue spaces $L^{p(\cdot)}(\mathbb{R}^n)$.


title: Astrometric detection of exoplanets from the ground

abstract:
  Astrometry is a powerful technique to study the populations of extrasolar
planets around nearby stars. It gives access to a unique parameter space and is
therefore required for obtaining a comprehensive picture of the properties,
abundances, and architectures of exoplanetary systems. In this review, we
discuss the scientific potential, present the available techniques and
instruments, and highlight a few results of astrometric planet searches, with
an emphasis on observations from the ground. In particular, we discuss
astrometric observations with the Very Large Telescope (VLT) Interferometer and
a programme employing optical imaging with a VLT camera, both aimed at the
astrometric detection of exoplanets. Finally, we set these efforts into the
context of Gaia, ESA's astrometry mission scheduled for launch in 2013, and
present an outlook on the future of astrometric exoplanet detection from the
ground.