title:
Explanation of hadron transverse-momentum spectra in heavy-ion
  collisions at sqrt(sNN) = 2.76 TeV within chemical non-equilibrium
  statistical hadronization model

abstract:
  Chemical non-equilibrium version of the statistical hadronization model
combined with a single-freeze-out scenario is used to analyze the
transverse-momentum spectra of pions, kaons and protons produced in heavy-ion
collisions at sqrt(sNN) = 2.76 TeV. With the statistical parameters found in
earlier studies of hadronic ratios and two new geometric parameters determined
by the absolute normalization and slopes of the spectra, we obtain a very good
agreement between the data and the model predictions. In particular, the
enhancement of pions observed at the very low transverse-momenta is very well
reproduced. In the chemical non-equilibrium approach, this effect may be
naturally interpreted as the onset of pion condensation in heavy-ion
collisions. We further stress that the chemical non-equilibrium explains not
only the proton yield but the proton spectra as well.


title: Form factors in quantum integrable models with GL(3)-invariant R-matrix

abstract:
  We study integrable models solvable by the nested algebraic Bethe ansatz and
possessing GL(3)-invariant R-matrix. We obtain determinant representations for
form factors of off-diagonal entries of the monodromy matrix. These
representations can be used for the calculation of form factors and correlation
functions of the XXX SU(3)-invariant Heisenberg chain.


title:
Measurement of electrons from heavy-flavour decays in Pb-Pb collisions
  at $\sqrt{s_{NN}} = 2.76$ TeV with ALICE

abstract:
  The measurement of heavy-flavour (charm and beauty) production in
ultra-relativistic heavy-ion collisions provides an important contribution to
the study of the properties of the hot and dense medium created in such
collisions. One approach to measure heavy-flavour production is via electrons
from semi-leptonic decays of heavy-flavour hadrons. In this contribution we
present the nuclear modification factor $(R_{{\rm{AA}}})$ and the azimuthal
anisotropy $(v_{2})$ of heavy-flavour decay electrons in Pb-Pb collisions at
$\sqrt{s_\mathit{{\rm{NN}}}}= 2.76$ TeV, which are sensitive to the interaction
of c and b quarks with the medium. We also present, for the first time, the
azimuthal angular correlations of heavy-flavour decay electrons and charged
hadrons, $\Delta\phi(\mathit{HFE},h)$, in Pb-Pb collisions and the
corresponding near-side yield ratio $(I_{\rm{AA}})$.


title:
High Energy Density Mixed Polymeric Phase From Carbon Monoxide and
  Nitrogen

abstract:
  Carbon monoxide and nitrogen are among the potentially interesting
high-energy density materials. However, in spite of the physical similarities
of the molecules, they behave very differently at high pressures. Using density
functional theory and structural prediction methods, we examine the ability of
these systems to combine their respective properties and form novel mixed
crystalline phases under pressures of up to 100 GPa. Interestingly, we find
that CO catalyzes the molecular dissociation of N2, which means mixed
structures are favored at a relatively low pressure (below 18 GPa), and that a
three-dimensional framework with Pbam symmetry becomes the most stable phase
above 52 GPa, i.e., at much milder conditions than in pure solid nitrogen. This
structure is dynamically stable at ambient pressure and has an energy density
of approximately 2:2 kJ/g, making it a candidate for a high-energy density
material, and one that could be achieved at less prohibitive experimental
conditions.


title: The Haagerup property for arbitrary von Neumann algebras

abstract:
  We introduce a natural generalization of the Haagerup property of a finite
von Neumann algebra to an arbitrary von Neumann algebra (with a separable
predual) equipped with a normal, semi-finite, faithful weight and prove that
this property does not depend on the choice of the weight. In particular this
defines the Haagerup property as an intrinsic invariant of the von Neumann
algebra. We also show that such a generalized Haagerup property is preserved
under taking crossed products by actions of amenable locally compact groups.
  Our results are motivated by recent examples from the theory of discrete
quantum groups, where the Haagerup property appears a priori only with respect
to the Haar state.


title:
A fast and robust algorithm to count topologically persistent holes in
  noisy clouds

abstract:
  Preprocessing a 2D image often produces a noisy cloud of interest points. We
study the problem of counting holes in unorganized clouds in the plane. The
holes in a given cloud are quantified by the topological persistence of their
boundary contours when the cloud is analyzed at all possible scales. We design
the algorithm to count holes that are most persistent in the filtration of
offsets (neighborhoods) around given points. The input is a cloud of $n$ points
in the plane without any user-defined parameters. The algorithm has $O(n\log
n)$ time and $O(n)$ space. The output is the array (number of holes, relative
persistence in the filtration). We prove theoretical guarantees when the
algorithm finds the correct number of holes (components in the complement) of
an unknown shape approximated by a cloud.


title:
Constraints on diffuse gamma-ray emission from structure formation
  processes in the Coma cluster

abstract:
  We analyze 5-year (63 months) data of the Large Area Telescope on board Fermi
satellite from the Coma galaxy cluster in the energy range between 100 MeV and
100 GeV. The likelihood analyses are performed with several templates motivated
by models predicting gamma-ray emission due to structure formation processes.
We find no excess emission and derive the most stringent constraints to date on
the Coma cluster above 100 MeV, and on the tested scenarios in general. The
upper limits on the integral flux range from 10^-10 to 10^-9 cm^-2s^-1, and are
stringent enough to challenge different scenarios. We find that the
acceleration efficiency of cosmic ray protons and electrons at shocks must be
below approximately 15% and 1%, respectively. Additionally, we argue that the
proton acceleration efficiency should be lower than 5% in order to be
consistent with radio data. This, however, relays on magnetic field estimates
in the cluster. In particular, this implies that the contribution to the
diffuse extragalactic gamma-ray background due to gamma-rays from structure
formation processes in clusters of galaxies is negligible, below 1%. Finally,
we discuss future detectability prospects for Astro-H, Fermi after 10-yr of
operation, and the Cherenkov Telescope Array.


title:
Approximating persistent homology for a cloud of $n$ points in a
  subquadratic time

abstract:
  The Vietoris-Rips filtration for an $n$-point metric space is a sequence of
large simplicial complexes adding a topological structure to the otherwise
disconnected space. The persistent homology is a key tool in topological data
analysis and studies topological features of data that persist over many
scales. The fastest algorithm for computing persistent homology of a filtration
has time $O(M(u)+u^2\log^2 u)$, where $u$ is the number of updates (additions
or deletions of simplices), $M(u)=O(u^{2.376})$ is the time for multiplication
of $u\times u$ matrices. For a space of $n$ points given by their pairwise
distances, we approximate the Vietoris-Rips filtration by a zigzag filtration
consisting of $u=o(n)$ updates, which is sublinear in $n$. The constant depends
on a given error of approximation and on the doubling dimension of the metric
space. Then the persistent homology of this sublinear-size filtration can be
computed in time $o(n^2)$, which is subquadratic in $n$.


title: Equivariant measurable liftings

abstract:
  We discuss equivariance for linear liftings of measurable functions.
Existence is established when a transformation group acts amenably, as e.g. the
Moebius group of the projective line.
  Since the general proof is very simple but not explicit, we also provide a
much more explicit lifting for semi-simple Lie groups acting on their
Furstenberg boundary, using unrestricted Fatou convergence. This setting is
relevant to cocycles for characteristic classes.


title:
Swimming path statistics of an active Brownian particle with
  time-dependent self-propulsion

abstract:
  Typically, in the description of active Brownian particles, a constant
effective propulsion force is assumed, which is then subjected to fluctuations
in orientation and translation leading to a persistent random walk with an
enlarged long-time diffusion coefficient. Here, we generalize previous results
for the swimming path statistics to a time-dependent and thus in many
situations more realistic propulsion which is a prescribed input. We
analytically calculate both the noise-free and the noise-averaged trajectories
for time-periodic propulsion under the action of an additional torque. In the
deterministic case, such an oscillatory microswimmer moves on closed paths that
can be highly more complicated than the commonly observed straight lines and
circles. When exposed to random fluctuations, the mean trajectories turn out to
be self-similar curves which bear the characteristics of their noise-free
counterparts. Furthermore, we consider a propulsion force which scales in time
$t$ as $\propto \! t^\alpha$ (with $\alpha=0,1,2,\ldots$) and analyze the
resulting superdiffusive behaviour. Our predictions are verifiable for
diffusiophoretic artificial microswimmers with prescribed propulsion protocols.


title: The combinatorics of an algebraic class of easy quantum groups

abstract:
  Easy quantum groups are compact matrix quantum groups, whose intertwiner
spaces are given by the combinatorics of categories of partitions. This class
contains the symmetric group and the orthogonal group as well as Wang's quantum
permutation group and his free orthogonal quantum group. In this article, we
study a particular class of categories of partitions to each of which we assign
a subgroup of the infinite free product of the cyclic group of order two. This
is an important step in the classification of all easy quantum groups and we
deduce that there are uncountably many of them. We focus on the combinatorial
aspects of this assignment, complementing the quantum algebraic point of view
presented in another article.


title: Counting processes with Bern\v{s}tein intertimes and random jumps

abstract:
  We consider here point processes $N^f(t)$, $t>0$, with independent increments
and integer-valued jumps whose distribution is expressed in terms of
Bern\v{s}tein functions $f$ with L\'evy measure $\nu$. We obtain the general
expression of the probability generating functions $G^f$ of $N^f$, the
equations governing the state probabilities $p_k^f$ of $N^f$, and their
corresponding explicit forms. We also give the distribution of the
first-passage times $T_k^f$ of $N^f$, and the related governing equation. We
study in detail the cases of the fractional Poisson process, the relativistic
Poisson process and the Gamma Poisson process whose state probabilities have
the form of a negative binomial. The distribution of the times $\tau_j^{l_j}$
of jumps with height $l_j$ ($\sum_{j=1}^rl_j = k$) under the condition $N(t) =
k$ for all these special processes is investigated in detail.


title: On Cohomology Rings of Non-Commutative Hilbert Schemes and CoHa-Modules

abstract:
  We prove that Chow groups of certain non-commutative Hilbert schemes have a
basis consisting of monomials in Chern classes of the universal bundle.
Furthermore, we realize the cohomology of non-commutative Hilbert schemes as a
module over the Cohomological Hall algebra.


title:
Asymptotic expansions of integral means and applications to the ratio of
  gamma functions

abstract:
  Integral means are important class of bivariate means. In this paper we prove
the very general algorithm for calculation of coefficients in asymptotic
expansion of integral mean. It is based on explicit solving the equation of the
form $B(A(x))=C(x)$, where $B$ and $C$ have known asymptotic expansions. The
results are illustrated by calculation of some important integral means
connected with gamma and digamma functions.


title:
Update of the ALEPH non-strange spectral functions from hadronic $\tau$
  decays

abstract:
  An update of the ALEPH non-strange spectral functions from hadronic $\tau$
decays is presented. Compared to the 2005 ALEPH publication, the main
improvement is related to the use of a new method to unfold the measured mass
spectra from detector effects. This procedure also corrects a previous problem
in the correlations between the unfolded mass bins. Results from QCD studies
and for the evaluation of the hadronic vacuum polarisation contribution to the
anomalous muon magnetic moment are derived using the new spectral functions.
They are found in agreement with published results based on the previous set of
spectral functions.


title:
On the average distribution of primes represented by binary quadratic
  forms

abstract:
  We investigate the average distribution of primes represented by positive
definite integral binary quadratic forms, the average being taken over negative
fundamental discriminants in long ranges. In particular, we prove corresponding
results of Bombieri-Vinogradov type and of Barban-Davenport-Halberstam type,
although with shorter ranges than in the original theorems for primes in
arithmetic progressions: The results imply that, for all $a>0$, the least prime
that can be represented by any given positive definite binary quadratic form of
discriminant $q$ is smaller than $|q|^{7+a}$ for all forms to "most"
discriminants; moreover, it is even smaller than $|q|^{3+a}$ for "most" forms
to "most" discriminants.


title:
Zero modes in magnetic systems: general theory and an efficient
  computational scheme

abstract:
  The presence of topological defects in magnetic media often leads to normal
modes with zero frequency (zero modes). Such modes are crucial for long-time
behavior, describing, for example, the motion of a domain wall as a whole.
Conventional numerical methods to calculate the spin-wave spectrum in magnetic
media are either inefficient or they fail for systems with zero modes. We
present a new efficient computational scheme that reduces the magnetic
normal-mode problem to a generalized Hermitian eigenvalue problem also in the
presence of zero modes. We apply our scheme to several examples, including
two-dimensional domain walls and Skyrmions, and show how the effective masses
that determine the dynamics can be calculated directly. These systems highlight
the fundamental distinction between the two types of zero modes that can occur
in spin systems, which we call special and inertial zero modes. Our method is
suitable for both conservative and dissipative systems. For the latter case, we
present a perturbative scheme to take into account damping, which can also be
used to calculate dynamical susceptibilities.


title: Benchmarking an Even Better HEPTopTagger

abstract:
  Top taggers are established analysis tools to reconstruct boosted
hadronically decaying top quarks for example in searches for heavy resonances.
We first present a dedicated study of signal efficiency versus background
rejection, allowing for an improved choice of working points. Next, we
determine to what degree our mass drop selection can be improved by
systematically including angular correlations between the decay subjets.
Finally, we extend the reach of the top tagger to transverse momenta below the
top mass. This momentum range will be crucial in searches for the associated
production of a Higgs boson with top quarks.


title:
Electrodynamics Modified by Some Dimension-five Lorentz Violating
  Interactions: Radiative Corrections

abstract:
  We study radiative corrections to massless quantum electrodynamics modified
by two dimension-five LV interactions $\bar{\Psi} \gamma^{\mu} b'^{\nu}
F_{\mu\nu}\Psi$ and $\bar{\Psi}\gamma^{\mu}b^{\nu} \tilde{F}_{\mu\nu} \Psi$ in
the framework of effective field theories. All divergent
one-particle-irreducible Feynman diagrams are calculated at one-loop order and
several related issues are discussed. It is found that massless quantum
electrodynamics modified by the interaction $\bar{\Psi} \gamma^{\mu} b'^{\nu}
F_{\mu\nu}\Psi$ alone is one-loop renormalizable and the result can be
understood on the grounds of symmetry. In this context the one-loop
Lorentz-violating beta function is derived and the corresponding running
coefficients are obtained.


title:
The Scale and Tidy Subgroups for Endomorphisms of Totally Disconnected
  Locally Compact Groups

abstract:
  The scale of an endomorphism, $\alpha$, of a totally disconnected, locally
compact group $G$ is the minimum index $[\alpha(U) : \alpha(U)\cap U]$, for $U$
a compact, open subgroup of $G$. A structural characterization of subgroups at
which the minimum is attained is established. This characterization extends the
notion of subgroup tidy for $\alpha$ from previously understood case when
$\alpha$ is an automorphism to the case when $\alpha$ is merely an
endomorphism.


title:
Doping asymmetry of superconductivity coexisting with antiferromagnetism
  in spin fluctuation theory

abstract:
  We generalize the theory of Cooper pairing by spin excitations in the
metallic antiferromagnetic state to include situations with electron and/or
hole pockets. We show that Cooper pairing arises from transverse spin waves and
from gapped longitudinal spin fluctuations of comparable strength. However,
each of these interactions, projected on a particular symmetry of the
superconducting gap, acts primarily within one type of pocket. We find a
nodeless $d_{x^2-y^2}$-wave state is supported primarily by the longitudinal
fluctuations on the electron pockets, and both transverse and longitudinal
fluctuations support nodeless odd-parity spin singlet $p-$wave symmetry on the
hole pockets. Our results may be relevant to the asymmetry of the AF/SC
coexistence state in the cuprate phase diagram, as well as for the "nodal gap"
observed recently for strongly underdoped cuprates.


title:
Photoelectron emission from plasmonic nanoparticles: Comparison between
  surface and volume photoelectric effects

abstract:
  We study emission of photoelectrons from plasmonic nanoparticles into
surrounding matrix. We consider two mechanisms of the photoelectric effect from
nanoparticles - surface and volume ones, and use models of these two effects
which allow us to obtain analytical results for the photoelectron emission
rates from nanoparticle. Calculations have been done for the step potential at
surface of spherical nanoparticle, and the simple model for the hot electron
cooling have been used. We highlight the effect of the discontinuity of the
dielectric permittivity at the nanoparticle boundary in the surface mechanism,
which leads to substantial (by 5 times) increase of photoelectron emission rate
from nanoparticle compared to the case when such discontinuity is absent. For
plasmonic nanoparticle, a comparison of two mechanisms of the photoeffect was
done for the first time and showed that surface photoeffect, at least, does not
concede the volume one, which agrees with results for the flat metal surface
first formulated by Tamm and Schubin in their pioneering development of
quantum-mechanical theory of photoeffect in 1931. In accordance with our
calculations, this predominance of the surface effect is a result of effective
cooling of hot carriers, during their propagation from volume of the
nanoparticle to its surface in the scenario of the volume mechanism. Taking
into account both mechanisms is essential in development of devices based on
the photoelectric effect and in usage of hot electrons from plasmonic
nanoantenna.


title: Testing for stationarity in multivariate locally stationary processes

abstract:
  In this paper we propose a nonparametric procedure for validating the
assumption of stationarity in multivariate locally stationary time series
models. We develop a bootstrap assisted test based on a Kolmogorov-Smirnov type
statistic, which tracks the deviation of the time varying spectral density from
its best stationary approximation. In contrast to all other nonparametric
approaches, which have been proposed in the literature so far, the test
statistic does not depend on any regularization parameters like smoothing
bandwidths or a window length, which is usually required in a segmentation of
the data. We additionally show how our new procedure can be used to identify
the components where non-stationarities occur and indicate possible extensions
of this innovative approach. We conclude with an extensive simulation study,
which shows finite sample properties of the new method and contains a
comparison with existing approaches.


title:
Optical observations of the nearby galaxy IC342 with narrow band [SII]
  and H$\alpha$ filters. I

abstract:
  We present observations of the portion of the nearby spiral galaxy IC342
using narrow band [SII] and H$\alpha$ filters. These observations were carried
out in November 2011 with the 2m RCC telescope at Rozhen National Astronomical
Observatory in Bulgaria. In this paper we report coordinates, diameters,
H$\alpha$ and [SII] fluxes for 203 HII regions detected in two fields of view
in IC342 galaxy. The number of detected HII regions is 5 times higher than
previously known in these two parts of the galaxy.


title: On categorical semigroups

abstract:
  The structure of categorical at zero semigroups is studied from the point of
view their likeness to categories.


title:
An adaptive block based integrated LDP,GLCM,and Morphological features
  for Face Recognition

abstract:
  This paper proposes a technique for automatic face recognition using
integrated multiple feature sets extracted from the significant blocks of a
gradient image. We discuss about the use of novel morphological, local
directional pattern (LDP) and gray-level co-occurrence matrix GLCM based
feature extraction technique to recognize human faces. Firstly, the new
morphological features i.e., features based on number of runs of pixels in four
directions (N,NE,E,NW) are extracted, together with the GLCM based statistical
features and LDP features that are less sensitive to the noise and
non-monotonic illumination changes, are extracted from the significant blocks
of the gradient image. Then these features are concatenated together. We
integrate the above mentioned methods to take full advantage of the three
approaches. Extraction of the significant blocks from the absolute gradient
image and hence from the original image to extract pertinent information with
the idea of dimension reduction forms the basis of the work. The efficiency of
our method is demonstrated by the experiment on 1100 images from the FRAV2D
face database, 2200 images from the FERET database, where the images vary in
pose, expression, illumination and scale and 400 images from the ORL face
database, where the images slightly vary in pose. Our method has shown 90.3%,
93% and 98.75% recognition accuracy for the FRAV2D, FERET and the ORL database
respectively.


title:
Constraints on Helium Enhancement in the Globular Cluster M4 (NGC 6121):
  The Horizontal Branch Test

abstract:
  Recent pieces of evidence have revealed that most, and possibly all, globular
star clusters are composed of groups of stars that formed in multiple episodes
with different chemical compositions. In this sense, it has also been argued
that variations in the initial helium abundance ($Y$) from one population to
the next are also the rule, rather than the exception. In the case of the
metal-intermediate globular cluster M4 (NGC 6121), recent high-resolution
spectroscopic observations of blue horizontal branch (HB) stars (i.e., HB stars
hotter than the RR Lyrae instability strip) suggest that a large fraction of
blue HB stars are second-generation stars formed with high helium abundances.
In this paper, we test this scenario by using recent photometric and
spectroscopic data together with theoretical evolutionary computations for
different $Y$ values. Comparing the photometric data with the
theoretically-derived color-magnitude diagrams, we find that the bulk of the
blue HB stars in M4 have $\Delta Y \lesssim 0.01$ with respect to the cluster's
red HB stars (i.e., HB stars cooler than the RR Lyrae strip)-- a result which
is corroborated by comparison with spectroscopically derived gravities and
temperatures, which also favor little He enhancement. However, the possible
existence of a minority population on the blue HB of the cluster with a
significant He enhancement level is also discussed.


title:
A novel method for the physical scale setting on the lattice and its
  application to $N_f$=4 simulations

abstract:
  This letter reports on a new procedure for the lattice spacing setting that
takes advantage of the very precise determination of the strong coupling in
Taylor scheme. Although it can be applied for the physical scale setting with
the experimental value of $\Lambda_{\overline{\rm MS}}$ as an input, the
procedure is particularly appropriate for relative "calibrations". The method
is here applied for simulations with four degenerate light quarks in the sea
and leads to prove that their physical scale is compatible with the same one
for simulations with two light and two heavy flavours.


title: Renormalization group flow equations from the 4PI equations of motion

abstract:
  The 4PI effective action provides a a hierarchy of integral equations which
have the form of Bethe-Salpeter equations. The vertex functions obtained from
these equations can be used to truncate the exact renormalization group flow
equations. This truncation has the property that the flow is a total derivative
with respect to the flow parameter and is equivalent to solving the nPI
equations of motion. This result establishes a direct connection between two
non-perturbative methods.


title: The essential norm of a weighted composition operator on BMOA

abstract:
  We provide an estimate for the essential norm of a weighted composition
operator $W_{\psi,\varphi}\colon f\mapsto \psi(f\circ\varphi)$ acting on the
space $BMOA$ in terms of the weight function $\psi$ and the $n$-th power
$\varphi^n$ of the analytic self-map $\varphi$ of the open unit disc
$\mathbb{D}$. We also provide a new estimate for the norm of the weighted
composition operator on $BMOA$.


title:
A Gabor block based Kernel Discriminative Common Vector (KDCV) approach
  using cosine kernels for Human Face Recognition

abstract:
  In this paper a nonlinear Gabor Wavelet Transform (GWT) discriminant feature
extraction approach for enhanced face recognition is proposed. Firstly, the
low-energized blocks from Gabor wavelet transformed images are extracted.
Secondly, the nonlinear discriminating features are analyzed and extracted from
the selected low-energized blocks by the generalized Kernel Discriminative
Common Vector (KDCV) method. The KDCV method is extended to include cosine
kernel function in the discriminating method. The KDCV with the cosine kernels
is then applied on the extracted low energized discriminating feature vectors
to obtain the real component of a complex quantity for face recognition. In
order to derive positive kernel discriminative vectors; we apply only those
kernel discriminative eigenvectors that are associated with non-zero
eigenvalues. The feasibility of the low energized Gabor block based generalized
KDCV method with cosine kernel function models has been successfully tested for
image classification using the L1, L2 distance measures; and the cosine
similarity measure on both frontal and pose-angled face recognition.
Experimental results on the FRAV2D and the FERET database demonstrate the
effectiveness of this new approach.


title:
"Double swallow-tail" singularity and glass-glass transition in a
  quasibinary system

abstract:
  The system with the square shoulder (SS) potential is considered in the frame
of Mode Coupling Theory (MCT) approach. An approximation for the structure
factor is used that emphasizes the quasibinary character of the system. The
qualitative phase diagram is constructed that includes continuous and
discontinuous glass-glass transitions. The phase diagram is governed by two
swallow tails connected with two $A_4$ singularities.


title:
Linear response within the projection-based renormalization method:
  Many-body corrections beyond the random phase approximation

abstract:
  The explicit evaluation of linear response coefficients for interacting
many-particle systems still poses a considerable challenge to theoreticians. In
this work we use a novel many-particle renormalization technique, the so-called
projector-based renormalization method, to show how such coefficients can
systematically be evaluated. To demonstrate the prospects and power of our
approach we consider the dynamical wave-vector dependent spin susceptibility of
the two-dimensional Hubbard model and also determine the subsequent magnetic
phase diagram close to half-filling. We show that the superior treatment of
(Coulomb) correlation and fluctuation effects within the projector-based
renormalization method significantly improves the standard random phase
approximation results.


title:
A Face Recognition approach based on entropy estimate of the nonlinear
  DCT features in the Logarithm Domain together with Kernel Entropy Component
  Analysis

abstract:
  This paper exploits the feature extraction capabilities of the discrete
cosine transform (DCT) together with an illumination normalization approach in
the logarithm domain that increase its robustness to variations in facial
geometry and illumination. Secondly in the same domain the entropy measures are
applied on the DCT coefficients so that maximum entropy preserving pixels can
be extracted as the feature vector. Thus the informative features of a face can
be extracted in a low dimensional space. Finally, the kernel entropy component
analysis (KECA) with an extension of arc cosine kernels is applied on the
extracted DCT coefficients that contribute most to the entropy estimate to
obtain only those real kernel ECA eigenvectors that are associated with
eigenvalues having high positive entropy contribution. The resulting system was
successfully tested on real image sequences and is robust to significant
partial occlusion and illumination changes, validated with the experiments on
the FERET, AR, FRAV2D and ORL face databases. Experimental comparison is
demonstrated to prove the superiority of the proposed approach in respect to
recognition accuracy. Using specificity and sensitivity we find that the best
is achieved when Renyi entropy is applied on the DCT coefficients. Extensive
experimental comparison is demonstrated to prove the superiority of the
proposed approach in respect to recognition accuracy. Moreover, the proposed
approach is very simple, computationally fast and can be implemented in any
real-time face recognition system.


title:
Evaluated Experimental Isobaric Analogue States from $T = 1/2$ to $T =
  3$ and associated IMME coefficients

abstract:
  Isobaric multiplets can be used to provide reliable mass predictions through
the Isobaric Multiplet Mass Equation (IMME). Isobaric analogue states (IAS) for
isospin multiplets from $T=1/2$ to $T=3$ have been studied within the 2012
Atomic Mass Evaluation (Ame2012). Each IAS established from published
experimental reaction data has been expressed in the form of a primary reaction
$Q$-value, and if necessary, has been recalibrated. The evaluated IAS masses
are provided here along with the associated IMME coefficients. Quadratic and
higher order forms of the IMME have been considered, and global trends have
been extracted. Particular nuclides, requiring experimental investigation, have
been identified and discussed. This dataset is the most precise and extensive
set of evaluated IAS to date.


title: Iterative Log Thresholding

abstract:
  Sparse reconstruction approaches using the re-weighted l1-penalty have been
shown, both empirically and theoretically, to provide a significant improvement
in recovering sparse signals in comparison to the l1-relaxation. However,
numerical optimization of such penalties involves solving problems with
l1-norms in the objective many times. Using the direct link of reweighted
l1-penalties to the concave log-regularizer for sparsity, we derive a simple
prox-like algorithm for the log-regularized formulation. The proximal splitting
step of the algorithm has a closed form solution, and we call the algorithm
'log-thresholding' in analogy to soft thresholding for the l1-penalty.
  We establish convergence results, and demonstrate that log-thresholding
provides more accurate sparse reconstructions compared to both soft and hard
thresholding. Furthermore, the approach can be directly extended to
optimization over matrices with penalty for rank (i.e. the nuclear norm penalty
and its re-weigthed version), where we suggest a singular-value
log-thresholding approach.


title: Efficient construction of broadcast graphs

abstract:
  A broadcast graph is a connected graph, $G=(V,E)$, $ |V |=n$, in which each
vertex can complete broadcasting of one message within at most $t=\lceil \log
n\rceil$ time units. A minimum broadcast graph on $n$ vertices is a broadcast
graph with the minimum number of edges over all broadcast graphs on $n$
vertices. The cardinality of the edge set of such a graph is denoted by $B(n)$.
In this paper we construct a new broadcast graph with
  $B(n) \le (k+1)N -(t-\frac{k}{2}+2)2^{k}+t-k+2$, for $n=N=(2^{k}-1)2^{t+1-k}$
and
  $B(n) \le (k+1-p)n -(t-\frac{k}{2}+p+2)2^{k}+t-k -(p-2)2^{p}$, for $2^{t} <
n<(2^{k}-1)2^{t+1-k}$, where $t \geq 7$, $2 \le k \le \lfloor t/2 \rfloor -1$
for even $n$ and $2 \le k \le \lceil t/2 \rceil -1$ for odd $n$, $d=N-n$, $x=
\lfloor \frac{d}{2^{t+1-k}} \rfloor$ and $ p = \lfloor \log_{2}{(x+1)} \rfloor$
if $x>0$ and $p=0$ if $x=0$.
  The new bound is an improvement upon the bound presented by Harutyunyan and
Liestman (2012) for odd values of $n$.


title: The bubble transform: A new tool for analysis of finite element methods

abstract:
  The purpose of this paper is to discuss the construction of a linear
operator, referred to as the bubble transform, which maps scalar functions
defined on a bounded domain $\Omega$ in $\mathbb{R}^n$ into a collection of
functions with local support. In fact, for a given simplicial triangulation of
$\Omega$, the associated bubble transform produces a decomposition of functions
on $\Omega$ into a sum of functions with support on the corresponding
macroelements. The transform is bounded in both $L^2$ and the Sobolev space
$H^1$, it is local, and it preserves the corresponding continuous piecewise
polynomial spaces. As a consequence, this transform is a useful tool for
constructing local projection operators into finite element spaces such that
the appropriate operator norms are bounded independently of polynomial degree.
The transform is basically constructed by two families of operators, local
averaging operators and rational trace preserving cut--off operators.


title: The search for $D^0\to{}e^{\pm}\mu^{\mp}$

abstract:
  An overview is presented of a method to search for $D^0\to{}e^{\pm}\mu^{\mp}$
with LHCb data. In order to reduce combinatorial backgrounds, tagged $D^0$
candidates from the decay $D^{\ast+}\to{}D^0\pi^+$ are used. This measurement
is performed with respect to $\mathcal{B}\left(D^0\to{}\pi^+\pi^-\right)$,
which cancels uncertainties in the luminosity and $D^{\ast+}$ production
cross-section. It is estimated that using $3\,\mathrm{fb}^{-1}$ of LHCb data an
upper limit can be attained of $\mathcal{O}\left(10^{-7}\right)$ at a $90\%$
confidence level.


title: Vertex Disjoint Path in Upward Planar Graphs

abstract:
  The $k$-vertex disjoint paths problem is one of the most studied problems in
algorithmic graph theory. In 1994, Schrijver proved that the problem can be
solved in polynomial time for every fixed $k$ when restricted to the class of
planar digraphs and it was a long standing open question whether it is
fixed-parameter tractable (with respect to parameter $k$) on this restricted
class. Only recently, \cite{CMPP}.\ achieved a major breakthrough and answered
the question positively. Despite the importance of this result (and the
brilliance of their proof), it is of rather theoretical importance. Their proof
technique is both technically extremely involved and also has at least double
exponential parameter dependence. Thus, it seems unrealistic that the algorithm
could actually be implemented. In this paper, therefore, we study a smaller
class of planar digraphs, the class of upward planar digraphs, a well studied
class of planar graphs which can be drawn in a plane such that all edges are
drawn upwards. We show that on the class of upward planar digraphs the problem
(i) remains NP-complete and (ii) the problem is fixed-parameter tractable.
While membership in FPT follows immediately from \cite{CMPP}'s general result,
our algorithm has only single exponential parameter dependency compared to the
double exponential parameter dependence for general planar digraphs.
Furthermore, our algorithm can easily be implemented, in contrast to the
algorithm in \cite{CMPP}.


title: Is polarization effect visible in leptonic SUSY searches?

abstract:
  On-shell effective theory approach has been widely used in search of various
supersymmetric signals, in particular, gluino/squark pairs with long cascade
decay chains in which complete matrix element calculations may encounter
over-20 dimensional integrations. On the other hand, leptons from polarized
chargino decays may show significant boost or anti-boost effect in some
scenarios and simulation without polarization information may underestimate or
overestimate the lepton $p_{T}$ cut efficiencies in the first place. We study
the polarization effects in supersymmetry searches of multi-jets plus leptons
final states. We find it justifiable for first two generations to only use
on-shell effective theories. While for measurements related to third generation
squarks, for instance, polarization effect of charginos from stop may reduce
the lepton $p_{T}$ cut efficiencies in cross section measurements by $25\%$
when slepton contributions dominate in chargino decay or $W$ are on-shell. The
signal is then underestimated if only on-shell effective theory approach is
taken in simulation of signal and the real bound on squark/gluino should be
more stringent.


title: Partial actions and automata

abstract:
  We use the notion of a partial action of a monoid to introduce a
generalization of automata, which we call "a preautomaton". We study properties
of preautomata and of languages recognized by preautomata.


title: Instruction sequences expressing multiplication algorithms

abstract:
  For each function on bit strings, its restriction to bit strings of any given
length can be computed by a finite instruction sequence that contains only
instructions to set and get the content of Boolean registers, forward jump
instructions, and a termination instruction. We describe instruction sequences
of this kind that compute the function on bit strings that models
multiplication on natural numbers less than $2^N$ with respect to their binary
representation by bit strings of length $N$, for a fixed but arbitrary $N > 0$,
according to the long multiplication algorithm and the Karatsuba multiplication
algorithm. We find among other things that the instruction sequence expressing
the former algorithm is longer than the one expressing the latter algorithm
only if the length of the bit strings involved is greater than $2^8$. We also
go into the use of an instruction sequence with backward jump instructions for
expressing the long multiplication algorithm. This leads to an instruction
sequence that it is shorter than the other two if the length of the bit strings
involved is greater than $2$.


title: Bandit Online Optimization Over the Permutahedron

abstract:
  The permutahedron is the convex polytope with vertex set consisting of the
vectors $(\pi(1),\dots, \pi(n))$ for all permutations (bijections) $\pi$ over
$\{1,\dots, n\}$. We study a bandit game in which, at each step $t$, an
adversary chooses a hidden weight weight vector $s_t$, a player chooses a
vertex $\pi_t$ of the permutahedron and suffers an observed loss of
$\sum_{i=1}^n \pi(i) s_t(i)$.
  A previous algorithm CombBand of Cesa-Bianchi et al (2009) guarantees a
regret of $O(n\sqrt{T \log n})$ for a time horizon of $T$. Unfortunately,
CombBand requires at each step an $n$-by-$n$ matrix permanent approximation to
within improved accuracy as $T$ grows, resulting in a total running time that
is super linear in $T$, making it impractical for large time horizons.
  We provide an algorithm of regret $O(n^{3/2}\sqrt{T})$ with total time
complexity $O(n^3T)$. The ideas are a combination of CombBand and a recent
algorithm by Ailon (2013) for online optimization over the permutahedron in the
full information setting. The technical core is a bound on the variance of the
Plackett-Luce noisy sorting process's "pseudo loss". The bound is obtained by
establishing positive semi-definiteness of a family of 3-by-3 matrices
generated from rational functions of exponentials of 3 parameters.


title: Measure theory and higher order arithmetic

abstract:
  We investigate the statement that the Lebesgue measure defined on all subsets
of the Cantor space exists. As base system we take $\mathsf{ACA}_0^\omega +
(\mu)$. The system $\mathsf{ACA}_0^\omega$ is the higher order extension of
Friedman's system $\mathsf{ACA}_0$, and $(\mu)$ denotes Feferman's $\mu$, that
is a uniform functional for arithmetical comprehension defined by $f(\mu(f))=0$
if $\exists n f(n)=0$ for $f\in \mathbb{N}^\mathbb{N}$.
  Feferman's $\mu$ will provide countable unions and intersections of sets of
reals and is, in fact, equivalent to this. For this reasons
$\mathsf{ACA}_0^\omega + (\mu)$ is the weakest fragment of higher order
arithmetic where $\sigma$-additive measures are directly definable.
  We obtain that over $\mathsf{ACA}_0^\omega + (\mu)$ the existence of the
Lebesgue measure is $\Pi^1_2$-conservative over $\mathsf{ACA}_0^\omega$ and
with this conservative over $\mathsf{PA}$. Moreover, we establish a
corresponding program extraction result.


title: Charge and spin transport in mesoscopic superconductors

abstract:
  Nonequilibrium charge transport in superconductors has been investigated
intensely in the 1970s and 80s, mostly in the vicinity of the critical
temperature. Much less attention has been focussed on low temperatures, and the
role of the quasiparticle spin. We report here on nonlocal transport in
superconductor hybrid structures at very low temperatures. By comparing the
nonlocal conductance obtained using ferromagnetic and normal-metal detectors,
we discriminate charge and spin degrees of freedom. We observe spin injection
and long-range transport of pure, chargeless spin currents in the regime of
large Zeeman splitting. We elucidate charge and spin tranport by comparison to
theoretical models. The observed long-range chargeless spin transport opens a
new path to manipulate and utilize the quasiparticle spin in superconductor
nanostructures.


title:
Small-angle scattering from three-phase systems: Investigation of the
  crossover between mass fractal regimes

abstract:
  In this paper, we construct a three-phase model (that is, a system consisting
of three homogeneous regions with various scattering length densities), which
illustrate the behavior of small-angle scattering (SAS) scattering curves. Here
two phases are a deterministic fractal embedded in another deterministic mass
fractal, and they altogether are further embedded in a third phase, which can
be a solution or solid matrix. We calculate SAS intensities, derive expressions
for the crossover position (that is, the point where the power-law scattering
exponent changes) as a function of control parameters, including size,
concentration, and volumes of each phase. The corresponding SAS intensities
from these models describe a succession of power-law regimes in momentum space
where both regimes correspond to mass fractals. The models can be applied to
SAS data where the absolute value of the scattering exponent of the first
power-law regime is higher than that of the subsequent second power-law regime,
that is, the scattering curve of convex kind near the crossover position.


title:
A Method for Analyzing the Non-Stationary Nucleation and Overall
  Transition Kinetics. A Case of Water

abstract:
  We present the statistical method as a direct extension of the mean
first-passage time concept to the analysis of molecular dynamics simulation
data of a phase transformation. According to the method, the mean first-passage
time trajectories for the first $(i=1)$ as well as for the subsequent ($i=2$,
$3$, $4$, $\ldots$) nucleation events should be extracted, that allows one to
calculate the time-dependent nucleation rate, the critical value of the order
parameter (the critical size), the waiting times for the nucleation events and
the growth law of the nuclei -- i.e. all the terms, which are usually necessary
to characterize the overall transition kinetics. There are no restrictions in
the application of the method by the specific thermodynamic regions; and the
nucleation rate parameters are extracted according to their basic definitions.
The method differs from the Wedekind-Bartell scheme and its modification [A.V.
Mokshin, B.N. Galimzyanov, J. Phys. Chem. B {\bf 116}, 11959 (2012)], where the
passage-times for the first (largest) nucleus are evaluated only and where the
average waiting time for the first nucleation event is accessible instead of
the true steady-state nucleation time scale. We demonstrate an efficiency of
the method by its application to the analysis of the vapor-to-liquid transition
kinetics in water at the different temperatures. The nucleation rate/time
characteristics and the droplet growth parameters are computed on the basis of
the coarse-grained molecular dynamics simulation data.

categories: cond-mat.soft cond-mat.mes-hall cond-mat.mtrl-sci physics.comp-ph physics.data-an


title:
Optimized dark matter searches in deep observations of Segue 1 with
  MAGIC

abstract:
  We present the results of stereoscopic observations of the satellite galaxy
Segue 1 with the MAGIC Telescopes, carried out between 2011 and 2013. With
almost 160 hours of good-quality data, this is the deepest observational
campaign on any dwarf galaxy performed so far in the very high energy range of
the electromagnetic spectrum. We search this large data sample for signals of
dark matter particles in the mass range between 100 GeV and 20 TeV. For this we
use the full likelihood analysis method, which provides optimal sensitivity to
characteristic gamma-ray spectral features, like those expected from dark
matter annihilation or decay. In particular, we focus our search on gamma-rays
produced from different final state Standard Model particles, annihilation with
internal bremsstrahlung, monochromatic lines and box-shaped signals. Our
results represent the most stringent constraints to the annihilation
cross-section or decay lifetime obtained from observations of satellite
galaxies, for masses above few hundred GeV. In particular, our strongest limit
(95% confidence level) corresponds to a ~500 GeV dark matter particle
annihilating into tau+tau-, and is of order <sigma v> ~ 1.2x10^{-24} cm^3
s^{-1} - a factor ~40 above the <sigma v> thermal value.


title: GLAMER Part II: Multiple Plane Gravitational Lensing

abstract:
  We present an extension to multiple planes of the gravitational lensing code
{\small GLAMER}. The method entails projecting the mass in the observed
light-cone onto a discrete number of lens planes and inverse ray-shooting from
the image to the source plane. The mass on each plane can be represented as
halos, simulation particles, a projected mass map extracted form a numerical
simulation or any combination of these. The image finding is done in a source
oriented fashion, where only regions of interest are iteratively refined on an
initially coarse image plane grid. The calculations are performed in parallel
on shared memory machines. The code is able to handle different types of
analytic halos (NFW, NSIE, power-law, etc.), haloes extracted from numerical
simulations and clusters constructed from semi-analytic models ({\small MOKA}).
Likewise, there are several different options for modeling the source(s) which
can be distributed throughout the light-cone. The distribution of matter in the
light-cone can be either taken from a pre-existing N-body numerical
simulations, from halo catalogs, or are generated from an analytic mass
function. We present several tests of the code and demonstrate some of its
applications such as generating mock images of galaxy and galaxy cluster
lenses.


title:
Reanalysis of the $Z_c(4020)$, $Z_c(4025)$, $Z(4050)$ and $Z(4250)$ as
  tetraquark states with QCD sum rules

abstract:
  In this article, we calculate the contributions of the vacuum condensates up
to dimension-10 in the operator product expansion, and study the
$C\gamma_\mu-C\gamma_\nu$ type scalar, axial-vector and tensor tetraquark
states in details with the QCD sum rules. In calculations, we use the formula
$\mu=\sqrt{M^2_{X/Y/Z}-(2{\mathbb{M}}_c)^2}$ to determine the energy scales of
the QCD spectral densities. The predictions $M_{J=2}
=\left(4.02^{+0.09}_{-0.09}\right)\,\rm{GeV}$, $M_{J=1}
=\left(4.02^{+0.07}_{-0.08}\right)\,\rm{GeV}$ favor assigning the $Z_c(4020)$
and $Z_c(4025)$ as the $J^{PC}=1^{+-}$ or $2^{++}$ diquark-antidiquark type
tetraquark states, while the prediction
$M_{J=0}=\left(3.85^{+0.15}_{-0.09}\right)\,\rm{GeV}$ disfavors assigning the
$Z(4050)$ and $Z(4250)$ as the $J^{PC}=0^{++}$ diquark-antidiquark type
tetraquark states. Furthermore, we discuss the strong decays of the $0^{++}$,
$1^{+-}$, $2^{++}$ diquark-antidiquark type tetraquark states in details.


title:
Gravitational Energy, Local Holography and Non-equilibrium
  Thermodynamics

abstract:
  We study the properties of gravitational system in finite regions bounded by
gravitational screens. We present the detail construction of the total energy
of such regions and of the energy and momentum balance equations due to the
flow of matter and gravitational radiation through the screen. We establish
that the gravitational screen possesses analogs of surface tension, internal
energy and viscous stress tensor, while the conservations are analogs of
non-equilibrium balance equations for a viscous system. This gives a precise
correspondence between gravity in finite regions and non-equilibrium
thermodynamics.


title: Photoproduction of Isolated Photons, Inclusively and with a Jet, at HERA

abstract:
  The photoproduction of isolated photons, both inclusive and together with a
jet, has been measured with the ZEUS detector at HERA using an integrated
luminosity of $374\, \mathrm{pb}^{-1}$. Differential cross sections are
presented in the isolated-photon transverse-energy and pseudorapidity ranges $6
< E_T^\gamma < 15$ GeV and $-0.7 < \eta^\gamma < 0.9,$ and for jet
transverse-energy and pseudorapidity ranges $4 < E_T^{jet} < 35$ GeV and $-1.5
< \eta^{jet} < 1.8,$ for exchanged-photon virtualities $Q^2 < 1$ GeV$^2$.
Differential cross sections are also presented for inclusive isolated-photon
production as functions of the transverse energy and pseudorapidity of the
photon. Higher-order theoretical calculations are compared to the results.


title: On an inequality in the problem of non-overlapping domains

abstract:
  Paper is devoted to extremal problems in geometric function theory of complex
variables associated with estimates of functionals defined on the systems of
non-overlapping domains. In particular, we strengthen some known result in this
subject.


title: Massless and massive representations in the spinor technique

abstract:
  The technique for representing spinors and the definition of the discrete
symmetries is used to illustrate on a toy model properties of massless and
massive spinors states, in the first and the second quantized picture. Since in
this toy model the number of the starting massless representations is well
defined as well as the origin of masses and charges in $d=(3+1)$ space, this
contribution might help to clarify the problem about Dirac, Weyl and Majorana
kinds of representations in physically more interesting cases.


title:
The Spin-Charge-Family theory offers the explanation for all the
  assumptions of the Standard model, for the Dark matter, for the
  Matter-antimatter asymmetry, making several predictions

abstract:
  The spin-charge-family theory, which is a kind of the Kaluza-Klein theories
but with fermions carrying two kinds of spins (no charges), offers the
explanation for all the assumptions of the standard model, with the origin of
families, the higgs and the Yukawa couplings included. It offers the
explanation also for other phenomena, like the origin of the dark matter and of
the matter/antimatter asymmetry in the universe. It predicts the existence of
the fourth family to the observed three, as well as several scalar fields with
the weak and the hyper charge of the standard model higgs ($\pm \frac{1}{2},
\mp \frac{1}{2}$, respectively), which determine the mass matrices of family
members, offering an explanation, why the fourth family with the masses above
$1$ TeV contributes weakly to the gluon-fusion production of the observed higgs
and to its decay into two photons, and predicting that the two photons events,
observed at the LHC at $\approx 750$ GeV, might be an indication for the
existence of one of several scalars predicted by this theory.


title: Scale hierarchy in high-temperature QCD

abstract:
  Because of asymptotic freedom, QCD becomes weakly interacting at high
temperature: this is the reason for the transition to a deconfined phase in
Yang-Mills theory at temperature $T_c$. At high temperature $T \gg T_c$, the
smallness of the running coupling $g$ induces a hierachy betwen the "hard",
"soft" and "ultrasoft" energy scales $T$, $g T$ and $g^2 T$. This hierarchy
allows for a very successful effective treatment where the "hard" and the
"soft" modes are successively integrated out. However, it is not clear how high
a temperature is necessary to achieve such a scale hierarchy.
  By numerical simulations, we show that the required temperatures are
extremely high. Thus, the quantitative success of the effective theory down to
temperatures of a few $T_c$ appears surprising a posteriori.


title: A decomposition of directed graphs and the Turan problem

abstract:
  We consider vertex decompositions of (di)graphs which appear in Automata
Theory, and establish some their properties. Then we apply them to the problem
of forbidden subgraphs.


title:
Radial quantization of the 3d CFT and the higher spin/vector model
  duality

abstract:
  We study the radial quantization of the 3d O(N) vector model. We calculate
the higher spin charges whose commutation relations give the higher spin
algebra. The Fock states of higher spin gravity in AdS_{4} are realized as the
states in the 3d CFT. The inner products between these states encode dynamical
information. The construction of bulk operators from CFT is discussed as well.
This serves as the simplest explicit demonstration of the CFT definition for
the quantum gravity.


title: The role of shear in dissipative gravitational collapse

abstract:
  In this paper we investigate the physics of a radiating star undergoing
dissipative collapse in the form of a radial heat flux. Our treatment clearly
demonstrates how the presence of shear affects the collapse process; we are in
a position to contrast the physical features of the collapsing sphere in the
presence of shear with the shear-free case. By employing a causal heat
transport equation of the Maxwell-Cattaneo form we show that the shear leads to
an enhancement of the core temperature thus emphasizing that relaxational
effects cannot be ignored when the star leaves hydrostatic equilibrium.


title: In-medium Eta-Nucleon interactions and Eta nuclear bound states

abstract:
  The in-medium Eta-N interaction near and below threshold is constructed from
a free-space chirally-inspired meson-baryon coupled-channel model that captures
the physics of the N(1535) baryon resonance. Nucleon Pauli blocking and hadron
self-energies are accounted for. The resulting energy dependent in-medium
interaction is used in self-consistent dynamical calculations of Eta nuclear
bound states. Narrow states of width about or less than 2 MeV are found across
the periodic table, beginning with A=10, for this in-medium coupled-channel
interaction model. The binding energy of the 1s-Eta state increases with A,
reaching a value of B(1s-Eta) about 15 MeV. The implications of our
self-consistency procedure are discussed with respect to procedures used in
other works.


title:
Model trees with topic model preprocessing: An approach for data
  journalism illustrated with the WikiLeaks Afghanistan war logs

abstract:
  The WikiLeaks Afghanistan war logs contain nearly $77,000$ reports of
incidents in the US-led Afghanistan war, covering the period from January 2004
to December 2009. The recent growth of data on complex social systems and the
potential to derive stories from them has shifted the focus of journalistic and
scientific attention increasingly toward data-driven journalism and
computational social science. In this paper we advocate the usage of modern
statistical methods for problems of data journalism and beyond, which may help
journalistic and scientific work and lead to additional insight. Using the
WikiLeaks Afghanistan war logs for illustration, we present an approach that
builds intelligible statistical models for interpretable segments in the data,
in this case to explore the fatality rates associated with different
circumstances in the Afghanistan war. Our approach combines preprocessing by
Latent Dirichlet Allocation (LDA) with model trees. LDA is used to process the
natural language information contained in each report summary by estimating
latent topics and assigning each report to one of them. Together with other
variables these topic assignments serve as splitting variables for finding
segments in the data to which local statistical models for the reported number
of fatalities are fitted. Segmentation and fitting is carried out with
recursive partitioning of negative binomial distributions. We identify segments
with different fatality rates that correspond to a small number of topics and
other variables as well as their interactions. Furthermore, we carve out the
similarities between segments and connect them to stories that have been
covered in the media. This gives an unprecedented description of the war in
Afghanistan and serves as an example of how data journalism, computational
social science and other areas with interest in database data can benefit from
modern statistical techniques.


title:
The orbital minimization method for electronic structure calculations
  with finite-range atomic basis sets

abstract:
  The implementation of the orbital minimization method (OMM) for solving the
self-consistent Kohn-Sham (KS) problem for electronic structure calculations in
a basis of non-orthogonal numerical atomic orbitals of finite-range is
reported. We explore the possibilities for using the OMM as an exact
cubic-scaling solver for the KS problem, and compare its performance with that
of explicit diagonalization in realistic systems. We analyze the efficiency of
the method depending on the choice of line search algorithm and on two free
parameters, the scale of the kinetic energy preconditioning and the
eigenspectrum shift. The results of several timing tests are then discussed,
showing that the OMM can achieve a noticeable speedup with respect to
diagonalization even for minimal basis sets for which the number of occupied
eigenstates represents a significant fraction of the total basis size (>15%).
We investigate the hard and soft parallel scaling of the method on multiple
cores, finding a performance equal to or better than diagonalization depending
on the details of the OMM implementation. Finally, we discuss the possibility
of making use of the natural sparsity of the operator matrices for this type of
basis, leading to a method that scales linearly with basis size.


title: Properties of Bigravity Solutions in a Solvable Class

abstract:
  We consider the properties of solutions in the bigravity theory for general
models, which are parametrized by two parameters $\alpha_{3}$ and $\alpha_{4}$.
Assuming that two metric tensors $g_{\mu \nu}$ and $f_{\mu \nu}$ satisfy the
condition $f_{\mu \nu}=C^{2}g_{\mu \nu}$ where $C$ is a constant, we
investigate the conditions for the parameters so that the solutions with
$C\neq1$ could exist. We also discuss the magnitude and the sign of
corresponding cosmological constants.
  For the black hole solution, we consider the black hole entropy to which the
massive spin-$2$ field contributes. In order to obtain the black hole entropy,
we take an approach which uses the Virasoro algebra and the central charge
corresponding to the surface term in the action.


title: Three-Body Interacting Bosons in Free Space

abstract:
  We propose a method of controlling two- and three-body interactions in an
ultracold Bose gas in any dimension. The method requires us to have two coupled
internal single-particle states split in energy such that the upper state is
occupied virtually but amply during collisions. By varying system parameters
one can switch off the two-body interaction while maintaining a strong
three-body one. The mechanism can be implemented for dipolar bosons in the
bilayer configuration with tunnelling or in an atomic system by using
radio-frequency fields to couple two hyperfine states. One can then aim to
observe a purely three-body-interacting gas, dilute self-trapped droplets, the
paired superfluid phase, Pfaffian state, and other exotic phenomena.


title:
The Cauchy problem for a fifth order KdV equation in weighted Sobolev
  spaces

abstract:
  In this work we study the initial value problem (IVP) for the fifth order KdV
equations, \begin{align*}
\partial_{t}u+\partial_{x}^{5}u+u^k\partial_{x}u=0,\text{} & \quad x,t\in
\mathbb R, \quad k=1,2, \end{align*} in weighted Sobolev spaces $H^s(\mathbb
R)\cap L^2(\langle x \rangle^{2r}dx)$. We prove local and global results. In
the case $k=2$ we point out the relation between decay and regularity of the
solution of the IVP.


title:
Efficiently preconditioned Inexact Newton methods for large symmetric
  eigenvalue problems

abstract:
  In this paper we propose an efficiently preconditioned Newton method for the
computation of the leftmost eigenpairs of large and sparse symmetric positive
definite matrices. A sequence of preconditioners based on the BFGS update
formula is proposed, for the Preconditioned Conjugate Gradient solution of the
linearized Newton system to solve $A \mathbf{u} = q(\mathbf{u}) \mathbf{u}$,
$q(\mathbf{u})$ being the Rayleigh Quotient. We give theoretical evidence that
the sequence of preconditioned Jacobians remains close to the identity matrix
if the initial preconditioned Jacobian is so. Numerical results onto matrices
arising from various realistic problems with size up to one million unknowns
account for the efficiency of the proposed algorithm which reveals competitive
with the Jacobi-Davidson method on all the test problems.


title: New Multiple Harmonic Sum Identities

abstract:
  We consider a special class of binomial sums involving harmonic numbers and
we prove three identities by using the elementary method of the partial
fraction decomposition. Some applications to infinite series and congruences
are given.


title: On the nature of the WO3 star DR1 in IC 1613

abstract:
  We present the results of a quantitative spectroscopic analysis of the
oxygen-sequence Wolf- Rayet star DR1 in the low-metallicity galaxy IC 1613. Our
models suggest that the strong oxygen emission lines are the result of the high
temperature of this WO3 star and do not necessarily reflect a more advanced
evolutionary stage than WC stars.


title: Precise Determination of the Charm Quark Mass

abstract:
  The determination of the charm quark mass is now possible to 1% from QCD,
with lattice QCD pushing the error down below 1%. I will describe the
ingredients of this approach and how it can achieve this accuracy. Results for
quark mass ratios, m_c/m_s and m_b/m_c, can also be determined to 1% from
lattice QCD, allowing accuracy for the heavy quark masses to be leveraged into
the light quark sector. I will discuss the prospects for, and importance of,
improving results in future calculations.


title: Magneto-optical spectroscopy with polarization-modulated light

abstract:
  We present a combined theoretical and experimental study of magnetic
resonance transitions induced by polarization-modulated light in cesium vapor
exposed to a transverse magnetic field. Signals are obtained by phase-sensitive
analysis of the light power traversing the vapor cell at six harmonics of the
polarization modulation frequency. Resonances appear whenever the Larmor
frequency matches an integer multiple of the modulation frequency. We have
further investigated the modifications of the spectra when varying the
modulation duty cycle. The resonance amplitudes of both in-phase and quadrature
components are well described in terms of the Fourier coefficients of the
modulation function. The background-free signals generated by the polarization
modulation scheme have a high application potential in atomic magnetometry.


title:
Efficient construction of the lattice of frequent closed patterns and
  simultaneous extraction of generic bases of rules

abstract:
  In the last few years, the amount of collected data, in various computer
science applications, has grown considerably. These large volumes of data need
to be analyzed in order to extract useful hidden knowledge. This work focuses
on association rule extraction. This technique is one of the most popular in
data mining. Nevertheless, the number of extracted association rules is often
very high, and many of them are redundant. In this paper, we propose a new
algorithm, called PRINCE. Its main feature is the construction of a partially
ordered structure for extracting subsets of association rules, called generic
bases. Without loss of information these subsets form representation of the
whole association rule set. To reduce the cost of such a construction, the
partially ordered structure is built thanks to the minimal generators
associated to frequent closed patterns. The closed ones are simultaneously
derived with generic bases thanks to a simple bottom-up traversal of the
obtained structure. The experimentations we carried out in benchmark and "worst
case" contexts showed the efficiency of the proposed algorithm, compared to
algorithms like CLOSE, A-CLOSE and TITANIC.


title: Outerstring graphs are $\chi$-bounded

abstract:
  An outerstring graph is an intersection graph of curves that lie in a common
half-plane and have one endpoint on the boundary of that half-plane. We prove
that the class of outerstring graphs is $\chi$-bounded, which means that their
chromatic number is bounded by a function of their clique number. This
generalizes a series of previous results on $\chi$-boundedness of outerstring
graphs with various additional restrictions on the shape of curves or the
number of times the pairs of curves can cross. The assumption that each curve
has an endpoint on the boundary of the half-plane is justified by the known
fact that triangle-free intersection graphs of straight-line segments can have
arbitrarily large chromatic number.


title: Bayesian object classification of gold nanoparticles

abstract:
  The properties of materials synthesized with nanoparticles (NPs) are highly
correlated to the sizes and shapes of the nanoparticles. The transmission
electron microscopy (TEM) imaging technique can be used to measure the
morphological characteristics of NPs, which can be simple circles or more
complex irregular polygons with varying degrees of scales and sizes. A major
difficulty in analyzing the TEM images is the overlapping of objects, having
different morphological properties with no specific information about the
number of objects present. Furthermore, the objects lying along the boundary
render automated image analysis much more difficult. To overcome these
challenges, we propose a Bayesian method based on the marked-point process
representation of the objects. We derive models, both for the marks which
parameterize the morphological aspects and the points which determine the
location of the objects. The proposed model is an automatic image segmentation
and classification procedure, which simultaneously detects the boundaries and
classifies the NPs into one of the predetermined shape families. We execute the
inference by sampling the posterior distribution using Markov chain Monte Carlo
(MCMC) since the posterior is doubly intractable. We apply our novel method to
several TEM imaging samples of gold NPs, producing the needed statistical
characterization of their morphology.


title:
On the Possibility of an Astronomical Perspective in the Study of Human
  Evolution

abstract:
  The Sapient Paradox is the apparently unexplainable time delay of several ten
thousand years following the arrival of Homo sapiens in Asia and Europe and
before the introduction of impressive innovations with the agricultural
revolution. Renfrew (2007) has suggested that the solution of the paradox has
to do with changes in modes of thought that occurred with sedentism. According
to Renfrew, this is a subject of study for cognitive archaeology where the
final goal would be to understand the formation of the human mind. Several
scholars, however, affirm that climatic change was crucial to such a revolution
as it would have been very difficult to develop agriculture during the
Palaeolithic. In other words, sedentism was not justified during the ice age,
and that may be the solution to the paradox. It is widely accepted that climate
variations were due to so-called orbital forcing, the slow periodic changes of
orbital parameters of the Earth (known also as the Milankovitch theory). These
and other astronomical effects on the climate are discussed along with the
consequent impact on human evolution. The question then rises as to whether or
not it is possible to adopt an astronomical perspective instead of (or
complementary to) the cognitive archaeological one. Such would be possible by
adopting a different point of reference (that is, from outside), and a
non-anthropocentric approach.


title: SLE and Virasoro representations: localization

abstract:
  We consider some probabilistic and analytic realizations of Virasoro
highest-weight representations. Specifically, we consider measures on paths
connecting points marked on the boundary of a (bordered) Riemann surface. These
Schramm-Loewner Evolution (SLE)- type measures are constructed by the method of
localization in path space. Their partition function (total mass) is the
highest-weight vector of a Virasoro representation, and the action is given by
Virasoro uniformization.
  We review the formalism of Virasoro uniformization, which allows to define a
canonical action of Virasoro generators on functions (or sections) on a -
suitably extended - Teichm\"uller space. Then we describe the construction of
families of measures on paths indexed by marked bordered Riemann surfaces.
Finally we relate these two notions by showing that the partition functions of
the latter generate a highest-weight representation - the quotient of a
reducible Verma module - for the former.


title: On degenerate sums of $m$-dependent variables

abstract:
  It is well-known that the central limit theorem holds for partial sums of a
stationary sequence $(X_i)$ of $m$-dependent random variables with finite
variance; however, the limit may be degenerate with variance 0 even if
$\mathrm{Var}(X_i)\neq0$. We show that this happens only in the case when
$X_i-\mathbb E X_i=Y_i-Y_{i-1}$ for an $(m-1)$-dependent stationary sequence
$(Y_i)$ with finite variance (a result implicit in earlier results), and give a
version for block factors. This yields a simple criterion that is a sufficient
condition for the limit not to degenerate. Two applications to subtree counts
in random trees are given.


title:
A Magnified View of the Kinematics and Morphology of RCSGA
  032727-132609: Zooming in on a Merger at z=1.7

abstract:
  We present a detailed analysis of multi-wavelength HST/WFC3 imaging and
Keck/OSIRIS near-IR AO-assisted integral field spectroscopy for a highly
magnified lensed galaxy at z=1.70. This young starburst is representative of
UV-selected star-forming galaxies (SFG) at z~2 and contains multiple individual
star-forming regions. Due to the lensing magnification, we can resolve spatial
scales down to 100pc in the source plane of the galaxy. The velocity field
shows disturbed kinematics suggestive of an ongoing interaction, and there is a
clear signature of a tidal tail. We constrain the age, reddening, SFR and
stellar mass of the star-forming clumps from SED modelling of the WFC3
photometry and measure their H-alpha luminosity, metallicity and outflow
properties from the OSIRIS data. With strong star formation driven outflows in
four clumps, RCSGA0327 is the first high redshift SFG at stellar mass <10^10
M_sun with spatially resolved stellar winds. We compare the H-alpha
luminosities, sizes and dispersions of the star-forming regions to other high-z
clumps as well as local giant HII regions and find no evidence for increased
clump star formation surface densities in interacting systems, unlike in the
local Universe. Spatially resolved SED modelling unveils an established stellar
population at the location of the largest clump and a second mass concentration
near the edge of the system which is not detected in H-alpha emission. This
suggests a picture of an equal-mass mixed major merger, which has not triggered
a new burst of star formation or caused a tidal tail in the gas-poor component.


title:
Perfectly Matched Layers versus discrete transparent boundary conditions
  in quantum device simulations

abstract:
  Discrete transparent boundary conditions (DTBC) and the Perfectly Matched
Layers (PML) method for the realization of open boundary conditions in quantum
device simulations are compared, based on the stationary and time-dependent
Schr\"odinger equation. The comparison includes scattering state, wave packet,
and transient scattering state simulations in one and two space dimensions. The
Schr\"odinger equation is discretized by a second-order Crank-Nicolson method
in case of DTBC. For the discretization with PML, symmetric second-, fourth,
and sixth-order spatial approximations as well as Crank-Nicolson and classical
Runge-Kutta time-integration methods are employed. In two space dimensions, a
ring-shaped quantum waveguide device is simulated in the stationary and
transient regime. As an application, a simulation of the Aharonov-Bohm effect
in this device is performed, showing the excitation of bound states localized
in the ring region. The numerical experiments show that the results obtained
from PML are comparable to those obtained using DTBC, while keeping the high
numerical efficiency and flexibility as well as the ease of implementation of
the former method.


title:
Matching of heavy-light flavour currents between HQET at order 1/m and
  QCD: I. Strategy and tree-level study

abstract:
  We present a strategy how to match the full set of components of the
heavy-light axial and vector currents in Heavy Quark Effective Theory (HQET),
up to and including 1/m-corrections, to QCD. While the ultimate goal is to
apply these matching conditions non-perturbatively, in this study we first have
implemented them at tree-level, in order to find good choices of the matching
observables with small O(1/m^2) contributions. They can later be employed in
the non-perturbative matching procedure which is a crucial part of precision
HQET computations of semileptonic decay form factors in lattice QCD.


title:
Off-center observers versus supernovae in inhomogeneous pressure
  universes

abstract:
  Exact luminosity distance and apparent magnitude formulas are applied to
Union2 557 supernovae sample in order to constrain possible position of an
observer outside of the center of symmetry in spherically symmetric
inhomogeneous pressure Stephani universes which are complementary to
inhomogeneous density Lema\^itre-Tolman-Bondi (LTB) void models. Two specific
models are investigated. The first which allows a barotropic equation of state
at the center of symmetry with no scale factor function being specified (model
IIA), and the second which has no barotropic equation of state at the center,
but has an explicit dust-like scale factor evolution (model IIB).
  It is shown that even at $3\sigma$ CL, an off-center observer cannot be
further than about 4.4 Gpc away from the center of symmetry which is comparable
to the reported size of a void in LTB models with the most likely value of the
distance from the center about 341 Mpc for model IIA and 68 Mpc for model IIB.
The off-center observer cannot be farther away from the center than about 577
Mpc for model IIB at $3\sigma$ CL. It is evaluated that the best-fit parameters
which characterize inhomogeneity are: $\Omega_{inh} = 0.77$ (dimensionless -
model IIA) and $\alpha = 7.31 \cdot 10^{-9}$ $(s/km)^{2/3} Mpc^{-4/3}$ (model
IIB).


title: A statistical mechanical study of mechanical dual molecular braiding

abstract:
  This is an archival document; the work contains theoretical development to be
used in new publications and to stimulate further development. Here, we develop
a statistical mechanical treatment of a braid formed of two molecules subject
to an external pulling force and an applied moment at one of the braid ends.
The braids, considered here, are those whose axis is straight when thermal
fluctuations are absent. Firstly, the geometry and topology of the fluctuating
braid are characterized and an energy functional is built, including a
generalized interaction potential between the two molecules. To obtain
expressions for the free energy, we use variational approximations for two
cases. In one case, the interaction potential is considered weak and steric
interactions between the two molecules determine the mean squared amplitude of
fluctuations in the braid radius. In the second case, where the interactions
are strong, the mean squared amplitude is self consistently calculated and the
effects of the intermolecular interaction on the twisting of the two molecules
in the braid are considered. In the last case, two specific examples are
considered. The first of these is two uniformly charged rods with a repulsive
mean field electrostatic interaction, as well as a shorter ranged attractive
component. This second component may model correlation forces. The second
example includes possible helix specific forces in a braid formed of two DNA
molecules.


title: Low scatter and ultra-low reflectivity measured in a fused silica window

abstract:
  We investigate the reflectivity and optical scattering characteristics at
1064\,nm of an antireflection coated fused silica window of the type being used
in the Advanced LIGO gravitational-wave detectors. Reflectivity is measured in
the ultra-low range of 5-10\,ppm (by vendor) and 14-30\,ppm (by us). Using an
angle-resolved scatterometer we measure the sample's Bidirectional Scattering
Distribution Function (BSDF) and use this to estimate its transmitted and
reflected scatter at roughly 20-40\,ppm and 1\,ppm, respectively, over the
range of angles measured. We further inspect the sample's low backscatter using
an imaging scatterometer, measuring an angle resolved BSDF below $10^{-6}$
sr$^{-1}$ for large angles (10$^\circ$--80$^\circ$ from incidence in the plane
of the beam). We use the associated images to (partially) isolate scatter from
different regions of the sample and find that scattering from the bulk fused
silica is on par with backscatter from the antireflection coated optical
surfaces. To confirm that the bulk scattering is caused by Rayleigh scattering,
we perform a separate experiment, measuring the scattering intensity versus
input polarization angle. We estimate that 0.9--1.3\,ppm of the backscatter can
be accounted for by Rayleigh scattering of the bulk fused silica. These results
indicate that modern antireflection coatings have low enough scatter to not
limit the total backscattering of thick fused silica optics.


title: Particle aggregation by positive dielectrophoresis

abstract:
  Particle aggregates are formed with viable yeast cells (Saccharomyces
cerevisiae) and bacterial cells (Escherichia coli and Micrococcus luteus), and
are assembled in an interdigitated-castelled microelectrode using positive
dielectrophoresis with an alternating current sinusoidal voltage of 2-20 V
peak-peak at 1 MHz. The height of S. cerevisiae aggregates are increased by the
addition of the ampholytes N-[2-hydroxyethyl] piperazine-n'-[2-ethanesulfonic
acid] (HEPES) or e-aminocaproic acid (EACA) due to the resulting rise in
permittivity of the aqueous solution. The mean height of S. cerevisiae
aggregates in the presence of 1 M HEPES was 25.7 % higher than achieved in an
ampholyte-free solution. Based on the results obtained, a next-generation
triangular grooved microelectrode is proposed as an alternative to the
interdigitated-castelled microelectrode. This innovation could mark a paradigm
shift from aggregating particles at specific regions of high electric strength
(e.g. electrode edge) towards a layer by layer aggregation of particles along a
microelectrode.


title: Quasi-free photoproduction of eta-mesons off 3He nuclei

abstract:
  Quasi-free photoproduction of $\eta$-mesons has been measured off nucleons
bound in $^3$He nuclei for incident photon energies from the threshold region
up to 1.4 GeV. The experiment was performed at the tagged photon facility of
the Mainz MAMI accelerator with an almost $4\pi$ covering electromagnetic
calorimeter, combining the TAPS and Crystal Ball detectors. The $\eta$-mesons
were detected in coincidence with the recoil nucleons. This allowed a
comparison of the production cross section off quasi-free protons and
quasi-free neutrons and a full kinematic reconstruction of the final state,
eliminating effects from nuclear Fermi motion. In the $S_{11}$(1535) resonance
peak, the data agree with the neutron/proton cross section ratio extracted from
measurements with deuteron targets. More importantly, the prominent structure
observed in photoproduction off quasi-free neutrons bound in the deuteron is
also clearly observed. Its parameters (width, strength) are consistent with the
expectations from the deuteron results. On an absolute scale the cross sections
for both quasi-free protons and neutrons are suppressed with respect to the
deuteron target pointing to significant nuclear final state interaction
effects.


title:
Quantum dissonance provide power to deterministic quantum computation
  with single qubit

abstract:
  Mixed state quantum computation can perform certain tasks which are believed
to be efficiently intractable on a classical computer. For a specific model of
mixed state quantum computation, namely, {\it deterministic quantum computation
with a single qubit} (DQC1), recent investigations suggest that quantum
correlations other than entanglement might be responsible for the power of DQC1
model. However, strictly speaking, the role of entanglement in this model of
computation was not entirely clear. We provide conclusive evidence that there
are instances where quantum entanglement is not present in any part of this
model, nevertheless we have advantage over classical computation. This
establishes the fact that quantum dissonance (quantum correlations) present in
fully separable states provide power to DQC1 model.


title:
Deformed Bose gas models aimed at taking into account both compositeness
  of particles and their interaction

abstract:
  We consider the deformed Bose gas model with the deformation structure
function that is the combination of a q-deformation and a quadratically
polynomial deformation. Such a choice of the unifying deformation structure
function enables us to describe the interacting gas of composite (two-fermionic
or two-bosonic) bosons. Using the relevant generalization of the Jackson
derivative, we derive a two-parametric expression for the total number of
particles, from which the deformed virial expansion of the equation of state is
obtained. The latter is interpreted as the virial expansion for the effective
description of a gas of interacting composite bosons with some interaction
potential.

categories: math-ph cond-mat.stat-mech gr-qc hep-th math.MP quant-ph


title: On the classification of discrete Hirota-type equations in 3D

abstract:
  In the series of recent publications we have proposed a novel approach to the
classification of integrable differential/difference equations in 3D based on
the requirement that hydrodynamic reductions of the corresponding
dispersionless limits are `inherited' by the dispersive equations. In this
paper we extend this to the fully discrete case. Our only constraint is that
the initial ansatz possesses a non-degenerate dispersionless limit (this is the
case for all known Hirota-type equations). Based on the method of deformations
of hydrodynamic reductions, we classify discrete 3D integrable Hirota-type
equations within various particularly interesting subclasses. Our method can be
viewed as an alternative to the conventional multi-dimensional consistency
approach.


title:
Numerical-analytical investigation into impact pipe driving in soil with
  dry friction. Part I: Nondeformable external medium

abstract:
  The study focuses on propagation of longitudinal waves in an elastic pipe
partly embedded in a medium with dry friction. Mathematical formulation of the
problem on the impact pipe driving into the soil is based on the model of
longitudinal vibration of an elastic rod with taking into account lateral
resistance. The lateral resistance of soil is described by the law of the
contact dry friction. Numerical and analytical solutions to problems on
longitudinal impulse loading of a pipe are compared.


title: Magnetic properties of ferromagnetic Pu2Pt3Si5

abstract:
  The structural, magnetic, and thermodynamic properties of a new plutonium
based compound, Pu2Pt3Si5, are reported. Single crystals produced by a Sn-flux
technique have been analyzed showing a ferromagnetic behavior at 58 K.
Pu2Pt3Si5 crystallizes in the U2Co3Si5-type orthorhombic Iabm structure (72)
with atomic parameters a = 9.9226(2) \AA, b = 11.4436(2) \AA and c = 6.0148(1)
\AA. The effective (\mu_eff ~0.74 \mu_B) and saturated (\mu_sat ~0.32 B/Pu)
moments as well as the Sommerfeld coefficient (\gamma_e ~2 mJ.mol-1.K-2/Pu)
could point towards 5f localization in this material.


title:
On Coordinating Ultra-Dense Wireless Access Networks: Optimization
  Modeling, Algorithms and Insights

abstract:
  Network densification along with universal resources reuse is expected to
play a key role in the realization of 5G radio access as an enabler for
delivering most of the anticipated network capacity improvements. On the one
hand, neither the expected additional spectrum allocation nor the forthcoming
novel air-interface processing techniques will be sufficient for sustaining the
anticipated exponentially-increasing mobile data traffic. On the other hand,
enhanced ultra-dense infrastructure deployments are expected to provide
remarkable capacity gains, regardless of the evolutionary or revolutionary
approach followed towards 5G development. In this work, we thoroughly examine
global network coordination as the main enabler for future 5G large dense
small-cell deployments. We propose a powerful radio resources coordination
framework through which interference management is handled network-wise and
jointly over multiple dimensions. In particular, we explore strategies for
pairing serving and served access nodes, partitioning the available network
resources, as well as dynamically allocating power per pair, towards optimizing
system performance and guaranteeing individual minimum performance levels. We
develop new optimization formulations, providing network scaling performance
upper bounds, along with lower complexity algorithmic solutions tailored to
large networks. We apply the proposed solutions to dense network deployments,
in order to obtain useful insights on network performance and optimization,
such as rate scaling, infrastructure density, optimal bandwidth partitioning
and spatial reuse factor optimization.


title: Credit Portfolio Management in a Turning Rates Environment

abstract:
  We give a detailed account of correlations between credit sector/quality and
treasury curve factors, using the robust framework of the Barclays POINT Global
Risk Model. Consistent with earlier studies, we find a strong negative
correlation between sector spreads and rate shifts. However, we also observe
that the correlations between spreads and Treasury twists reversed recently,
which is likely attributable to the Fed's ongoing quantitative easing. We also
find that short-term effective durations in the banking industry are now
significantly lower than historical patterns would indicate. Our findings are
relevant for credit portfolio managers contemplating the impact of rising
interest rates and steepening Treasury curve on corporate bond portfolios.


title: Modulational Instability in the Whitham Equation for Water Waves

abstract:
  We show that periodic traveling waves with sufficiently small amplitudes of
the Whitham equation, which incorporates the dispersion relation of surface
water waves and the nonlinearity of the shallow water equations,are spectrally
unstable to long wavelengths perturbations if the wave number is greater than a
critical value, bearing out the Benjamin-Feir instability of Stokes waves; they
are spectrally stable to square integrable perturbations otherwise. The proof
involves a spectral perturbation of the associated linearized operator with
respect to the Floquet exponent and the small amplitude parameter. We extend
the results to related, nonlinear dispersive equations.


title: Singularity Propagation for the Gurtin-Pipkin equation

abstract:
  We show that the Dirac delta function in the boundary condition of the
Gurtin-Pipkin equation generates a moving delta-function with an exponentially
decreasing factor.


title:
Large isoperimetric regions in the product of a compact manifold with
  Euclidean space

abstract:
  Given a compact Riemannian manifold $M$ without boundary, we show that large
isoperimetric regions in $M\times\mathbb{R}^k$ are tubular neighborhoods of
$M\times\{x\}$, with $x\in\mathbb{R}^k$.


title:
Numerical-analytical investigation into impact pipe driving in soil with
  dry friction. Part II: Deformable external medium

abstract:
  Under analysis is travel of P-waves in an elastic pipe partly embedded in
soil with dry friction. The mathematical formulation of the problem on impact
pipe driving in soil is based on the model of axial vibration of an elastic
bar, considering lateral resistance described using the law of solid dry
friction. The author solves problems on axial load on pipe in interaction with
external elastic medium, and compares the analytical and numerical results
obtained with and without accounting for the external medium deformability.


title: Sequences with high nonlinear complexity

abstract:
  We improve lower bounds on the $k$th-order nonlinear complexity of
pseudorandom sequences over finite fields and we establish a probabilistic
result on the behavior of the $k$th-order nonlinear complexity of random
sequences over finite fields.


title: On the integral cohomology of quotients of manifolds by cyclic groups

abstract:
  We propose new tools based on basic lattice theory to calculate the integral
cohomology of the quotient of a manifold by an automorphism group of prime
order. As examples of applications, we provide the Beauville--Bogomolov forms
of some irreducible symplectic orbifolds; we also show a new expression for a
basis of the integral cohomology of a Hilbert scheme of two points on a
surface.


title:
Feasibility Studies for the Detection of $O_2$ in an Earth-like
  Exoplanet

abstract:
  We present the results of simulations on the detectability of $O_2$ in the
atmosphere of Earth twins around nearby low mass stars using high resolution
transmission spectroscopy. We explore such detectability with each of the three
upcoming Extremely Large Telescopes (ELTs), i.e. GMT, TMT and E-ELT, and high
resolution spectrographs, assuming such instruments will be available in all
ELTs. With these simulations we extend previous studies by taking into account
atmospheric refraction in the transmission spectrum of the exo-Earth and
observational white and red noise contributions. Our studies reveal that the
number of transits necessary to detect the $O_2$ in the atmosphere of an Earth
twin around M-dwarfs is by far higher than the number of transits estimated by
Snellen et al. (2013). In addition, our simulations show that, when accounting
for typical noise levels associated to observations in the optical and
near-infrared, the $O_2$ A-band at 760 nm is more favorable to detect the
exoplanetary signal than the $O_2$ band at 1268 nm for all the spectral types,
except M9V. We conclude that, unless unpredicted instrumental limitations
arise, the implementation of pre-slit optics such as image slicers appear to be
key to significantly improve the yield of this particular science case.
However, even in the most optimistic cases, we conclude that the detection of
$O_2$ in the atmosphere of an Earth twin will be only feasible with the ELTs if
the planet is orbiting a bright close-by (d $\le$ 8 pc) M-dwarf with a spectral
type later than M3.


title: Impact of Detector Solenoid on the CLIC Luminosity Performance

abstract:
  In order to obtain the necessary luminosity with a reasonable amount of beam
power, the Compact Linear Collider (CLIC) design includes an unprecedented
collision beam size of {\sigma} = 1 nm vertically and {\sigma} = 45 nm
horizontally. Given the small and very flat beams, the luminosity can be
significantly degraded from the impact of the experimental solenoid field in
combination with a large crossing angle. Main effects include y-x'-coupling and
increase of vertical dispersion. Additionally, Incoherent Synchrotron Radiation
(ISR) from the orbit deflection created by the solenoid field, increases the
beam emittance. A detailed study of the impact from a realistic solenoid field
and the associated correction techniques for the CLIC Final Focus is presented.
In particular, the impact of techniques to compensate the beam optics
distortions due to the detector solenoid main field and its overlap with the
final focus magnets are shown. The unrecoverable luminosity loss due to ISR has
been evaluated, and found to be in the range 4-5 % for the solenoid design
under study.


title: New developments on the Geometric Nonholonomic Integrator

abstract:
  In this paper, we will discuss new developments regarding the Geometric
Nonholonomic Integrator (GNI) [23, 24]. GNI is a discretization scheme adapted
to nonholonomic mechanical systems through a discrete geometric approach. This
method was designed to account for some of the special geometric structures
associated to a nonholonomic motion, like preservation of energy, preservation
of constraints or the nonholonomic momentum equation. First, we study the GNI
versions of the symplectic-Euler methods, paying special attention to their
convergence behavior. Then, we construct an extension of the GNI in the case of
affine constraints. Finally, we generalize the proposed method to nonholonomic
reduced systems, an important subclass of examples in nonholonomic dynamics. We
illustrate the behavior of the proposed method with the example of the
Chaplygin sphere, which accounts for the last two features, namely it is both a
reduced and an affine system.


title: Charge density wave instability in holographic d-wave superconductor

abstract:
  We report the observation of the spatially modulated static mode in the
spectrum of fluctuations around the condensed phase of the holographic d-wave
superconductor. The mode involves the time component of the gauge field that is
related to the charge density wave in the dual superconductor. No additional
ingredients are added to the action of five dimensional theory. We speculate on
the relevance of the observed mode to the formation of the pseudogap state.


title:
The Generation of Quantum Hamiltonian Evolution from A
  Pseudo-Measurement Process

abstract:
  Here we shall consider the idea that the Hamiltonian evolution of a quantum
system is generated by sequential observations of the system by a
`pseudo-apparatus'. This representation of Hamiltonian dynamics, originally
discovered by Belavkin, is a canonical dilation of the Schroedinger equation
that reveals a Minkowski space structure outside of the context of Special
Relativity. In particular, this formalism gives rise to the notion of a Boosted
Schroedinger equation referred to a dilated time increment which is the
manifestation of a Lorentz transform in the Minkowski space of the apparatus.


title: Recent results in cosmic ray physics and their interpretation

abstract:
  The last decade has been dense with new developments in the search for the
sources of Galactic cosmic rays. Some of these developments have confirmed the
tight connection between cosmic rays and supernovae in our Galaxy, through the
detection of gamma rays and the observation of thin non-thermal X-ray rims in
supernova remnants. Some other, such as the detection of features in the
spectra of some chemicals opened new questions on the propagation of cosmic
rays in the Galaxy and on details of the acceleration process. Here I will
summarize some of these developments and their implications for our
understanding of the origin of cosmic rays. I will also discuss some new
avenues that are being pursued in testing the supernova origin of Galactic
cosmic rays.