title:
A multiscale HDG method for second order elliptic equations. Part I.
  Polynomial and homogenization-based multiscale spaces

abstract:
  We introduce a finite element method for numerical upscaling of second order
elliptic equations with highly heterogeneous coefficients. The method is based
on a mixed formulation of the problem and the concepts of the domain
decomposition and the hybrid discontinuous Galerkin methods. The method
utilizes three different scales: (1) the scale of the partition of the domain
of the problem, (2) the sale of partition of the boundaries of the subdomains
(related to the corresponding space of Lagrange multipliers), and (3) the fine
grid scale that is assumed to resolve the scale of the heterogeneous variation
of the coefficients. Our proposed method gives a flexible framework that (1)
couples independently generated multiscale basis functions in each coarse patch
(2) provides a stable global coupling independent of local discretization,
physical scales and contrast (3) allows avoiding any constraints on coarse
spaces. In this paper, we develop and study a multiscale HDG method that uses
polynomial and homogenization-based multiscale spaces. These coarse spaces are
designed for problems with scale separation. In our consequent paper, we plan
to extend our flexible HDG framework to more challenging multiscale problems
with non-separable scales and high contrast and consider enriched coarse spaces
that use appropriate local spectral problems.


title:
A Two-Level Method for Mimetic Finite Difference Discretizations of
  Elliptic Problems

abstract:
  We propose and analyze a two-level method for mimetic finite difference
approximations of second order elliptic boundary value problems. We prove that
the two-level algorithm is uniformly convergent, i.e., the number of iterations
needed to achieve convergence is uniformly bounded independently of the
characteristic size of the underling partition. We also show that the resulting
scheme provides a uniform preconditioner with respect to the number of degrees
of freedom. Numerical results that validate the theory are also presented.


title: Very-high-energy quasars hint at ALPs

abstract:
  One of the mysteries of very-high-energy (VHE) astrophysics is the
observation of flat spectrum radio quasars (FSRQs) above about 30 GeV, because
at those energies their broad line region should prevent photons produced by
the central engine to escape. Although a few astrophysical explanations have
been put forward, they are totally ad hoc. We show that a natural explanation
emerges within the conventional models of FSRQs provided that photon-ALP
oscillations take place inside the source for the model parameters within an
allowed range.


title: MIT App Inventor: Enabling Personal Mobile Computing

abstract:
  MIT App Inventor is a drag-and-drop visual programming tool for designing and
building fully functional mobile apps for Android. App Inventor promotes a new
era of personal mobile computing in which people are empowered to design,
create, and use personally meaningful mobile technology solutions for their
daily lives, in endlessly unique situations. App Inventor's intuitive
programming metaphor and incremental development capabilities allow the
developer to focus on the logic for programming an app rather than the syntax
of the coding language, fostering digital literacy for all. Since it was moved
from Google to MIT, a number of improvements have been added, and research
projects are underway.


title: On the homology and homotopy of commutative shuffle algebras

abstract:
  For commutative algebras there are three important homology theories,
Harrison homology, Andre-Quillen homology and Gamma-homology. In general these
differ, unless one works with respect to a ground field of characteristic zero.
We show that the analogues of these homology theories agree in the category of
pointed commutative monoids in symmetric sequences and that Hochschild homology
always possesses a Hodge decomposition in this setting. In addition we prove
that the category of pointed differential graded commutative monoids in
symmetric sequences has a model structure and that it is Quillen equivalent to
the model category of pointed simplicial commutative monoids in symmetric
sequences.


title:
An approach for a business-driven cloudcompliance analysis covering
  public sector process improvement requirements

abstract:
  The need for process improvement is an important target that does affect as
well the government processes. Specifically in the public sector there are
specific challenges to face.New technology approaches within government
processes such as cloud services are necessary to address these challenges.
Following the current discussion of cloudification of business processes all
processes are considered similar in regards to their usability within the
cloud. The truth is, that neither all processes have the same usability for
cloud services not do they have the same importance for a specific company.The
most comprehensive process within a company is the corporate value chain. In
this article one key proposition is to use the corporate value chain as the
fundamental structuring backbone for all business process analysis and
improvement activities. It is a pre-requisite to identify the core elements of
the value chain that are essential for the individual companys business and the
root cause for any company success. In this paper we propose to use the
company-specific value-creation for the cloud-affinity and the cloud-usability
of a business process in public sector considering the specific challenges of
addressing processes in cloud services. Therefor it is necessary to formalize
the way the processes with its interdependencies are documented in context of
their company-specific value chain (as part of the various deployment- and
governance alternatives. Moreover, it is essential in the public sector to
describe in detail the environmental and external restrictions of processes.
With the use of this proposed methodology it becomes relatively easy to
identify cloud-suitable processes within the public sector and thus optimize
the public companies value generation tightly focused with the use of this new
technology.


title: Faa di Bruno's formula for chain differentials

abstract:
  This paper determines the general formula for describing differentials of
composite functions in terms of differentials of their factor functions. This
generalises the formula commonly attributed to Faa di Bruno to functions in
locally convex topological vector spaces. The result highlights the general
structure of the higher-order chain rule in terms of partitions of the
directions.


title:
The Bohr radius of the $n$-dimensional polydisk is equivalent to
  $\sqrt{\frac{\log n}{n}}$

abstract:
  We show that the Bohr radius of the polydisk $\mathbb D^n$ behaves
asymptotically as $\sqrt{(\log n)/n}$. Our argument is based on a new
interpolative approach to the Bohnenblust--Hille inequalities which allows us
to prove that the polynomial Bohnenblust--Hille inequality is subexponential.


title: A general method for the determination of duration of solar cycle maxima

abstract:
  The use of different solar activity indices like sunspot numbers, sunspot
areas, flare index, magnetic fields, etc., allows us to investigate the time
evolution of some specific features of the solar activity and the underlying
dynamo mechanism. One of the problems when using these activity indices for
some statistical analyses is the reliable determination of the maximum phases
of different solar cycles which are generally characterized by a multi-peaked
structure due to the presence of the so-called \emph {Gnevyshev gap}. The main
aim of this work is to propose a general method, without the introduction of ad
hoc heuristic parameters, to determine the duration of a given solar cycle
maximum phase through a long-term solar activity index like the Monthly
Smoothed Sunspot Number (SSN). The resulting extended solar maxima allows us to
include the multi-peaked structure of solar cycles and further the proposed
method allows us to predict the solar maximum duration of the current solar
cycle 24.


title:
The soft X-ray spectrum of the luminous narrow line Seyfert galaxy
  PG1211+143 - evidence for a second high velocity outflow component

abstract:
  An XMM-Newton observation of the luminous Seyfert galaxy PG1211+143 in 2001
revealed the first clear evidence for a highly ionised high speed wind (in a
non-BAL AGN), with a velocity of v~0.09c based on the identification of
blue-shifted absorption lines in both EPIC and RGS spectra. A subsequent
analysis of EPIC spectra, including additional absorption lines, led to an
upward revision of the wind speed to ~0.14c, while broad band modelling
indicated the need for a second, partial covering absorber to account for
continuum curvature and spectral variability. We show here, in a new analysis
of the XMM-Newton RGS data, that this additional absorber is detected in the
soft X-ray spectra, with the higher spectral resolution providing a much
improved velocity constraint, with v~0.07c. Similar variability of the 0.07c
and 0.14c outflow components suggest they are physically linked, and we
speculate that occurs by the fast (primary) wind impacting on small clumps of
higher density, slow moving matter close to the disc. We show that strong,
velocity broadened soft X-ray emission features, located at the redshift of
PG1211+143, indicate the extended scale of the ionised outflow.


title: Lagrangian mean curvature flow of pinched submanifolds of CP^n

abstract:
  We consider the evolution by mean curvature flow of Lagrangian submanifolds
of the complex projective space CP^n. We prove that, if the initial value
satisfies a suitable pinching condition, then the flow exists for all times and
the manifold converges to a totally geodesic submanifold. As a corollary, we
obtain that a Lagrangian submanifold satisfying our pinching condition is
diffeomorphic to a real projective space.


title: Scalar potentials, propagators and global symmetries in AdS/CFT

abstract:
  We study the transition of a scalar field in a fixed $AdS_{d+1}$ background
between an extremum and a minimum of a potential. We first prove that two
conditions must be met for the solution to exist. First, the potential involved
cannot be generic, i.e. a fine-tuning of their parameters is mandatory. Second,
at least in some region its second derivative must have a negative upper limit
which depends only on the dimensionality $d$. We then calculate the boundary
propagator for small momenta in two different ways: first in a WKB
approximation, and second with the usual matching method, generalizing the
known calculation to arbitrary order. Finally, we study a system with
spontaneously broken non-Abelian global symmetry, and show in the holographic
language why the Goldstone modes appear.


title:
Asymptotic regime for hadron-hadron diffractive collisions at ultrahigh
  energies

abstract:
  Using the pre-LHC and LHC data for $\pi p$ and $pp$ diffractive collisions we
study the ultrahigh energy asymptotic regime in the framework of the black disk
picture. The black disk picture, being constrained by the s-channel unitarity
condition and the $t$-channel analyticity, gives rather definite predictions
for diffractive processes increasing with the energy. To deal with the data, we
consider the Dakhno-Nikonov eikonal model which predicts a growth of the
$\ln^2s$ type for total and elastic cross sections and $(\tau={\bf
q}_\perp^2\ln^2s)$-scaling for diffractive scattering and diffractive
dissociation of hadrons. According to the calculations, ultrahigh energy
asymptotic characteristics of diffractive and total cross sections are
universal, and this results in the asymptotic equality of cross sections for
all types of hadrons. We estimate the energy scale of the asymptotics in
different processes. The manifestation of the asymptotic regime in hadron
fragmentation reactions is discussed.


title:
Photometric classification of emission line galaxies with Machine
  Learning methods

abstract:
  In this paper we discuss an application of machine learning based methods to
the identification of candidate AGN from optical survey data and to the
automatic classification of AGNs in broad classes. We applied four different
machine learning algorithms, namely the Multi Layer Perceptron (MLP), trained
respectively with the Conjugate Gradient, Scaled Conjugate Gradient and Quasi
Newton learning rules, and the Support Vector Machines (SVM), to tackle the
problem of the classification of emission line galaxies in different classes,
mainly AGNs vs non-AGNs, obtained using optical photometry in place of the
diagnostics based on line intensity ratios which are classically used in the
literature. Using the same photometric features we discuss also the behavior of
the classifiers on finer AGN classification tasks, namely Seyfert I vs Seyfert
II and Seyfert vs LINER. Furthermore we describe the algorithms employed, the
samples of spectroscopically classified galaxies used to train the algorithms,
the procedure followed to select the photometric parameters and the
performances of our methods in terms of multiple statistical indicators. The
results of the experiments show that the application of self adaptive data
mining algorithms trained on spectroscopic data sets and applied to carefully
chosen photometric parameters represents a viable alternative to the classical
methods that employ time-consuming spectroscopic observations.


title: Half-integrality, LP-branching and FPT Algorithms

abstract:
  A recent trend in parameterized algorithms is the application of polytope
tools (specifically, LP-branching) to FPT algorithms (e.g., Cygan et al., 2011;
Narayanaswamy et al., 2012). However, although interesting results have been
achieved, the methods require the underlying polytope to have very restrictive
properties (half-integrality and persistence), which are known only for few
problems (essentially Vertex Cover (Nemhauser and Trotter, 1975) and Node
Multiway Cut (Garg et al., 1994)). Taking a slightly different approach, we
view half-integrality as a \emph{discrete} relaxation of a problem, e.g., a
relaxation of the search space from $\{0,1\}^V$ to $\{0,1/2,1\}^V$ such that
the new problem admits a polynomial-time exact solution. Using tools from CSP
(in particular Thapper and \v{Z}ivn\'y, 2012) to study the existence of such
relaxations, we provide a much broader class of half-integral polytopes with
the required properties, unifying and extending previously known cases.
  In addition to the insight into problems with half-integral relaxations, our
results yield a range of new and improved FPT algorithms, including an
$O^*(|\Sigma|^{2k})$-time algorithm for node-deletion Unique Label Cover with
label set $\Sigma$ and an $O^*(4^k)$-time algorithm for Group Feedback Vertex
Set, including the setting where the group is only given by oracle access. All
these significantly improve on previous results. The latter result also implies
the first single-exponential time FPT algorithm for Subset Feedback Vertex Set,
answering an open question of Cygan et al. (2012).
  Additionally, we propose a network flow-based approach to solve some cases of
the relaxation problem. This gives the first linear-time FPT algorithm to
edge-deletion Unique Label Cover.


title: Wavelet methods for shape perception in electro-sensing

abstract:
  This paper aims at presenting a new approach to the electro-sensing problem
using wavelets. It provides an efficient algorithm for recognizing the shape of
a target from micro-electrical impedance measurements. Stability and resolution
capabilities of the proposed algorithm are quantified in numerical simulations.


title:
Vector-boson pair production at the LHC: Electroweak corrections in
  HERWIG++

abstract:
  Vector-boson pair production is of great phenomenological importance at the
LHC. These processes will help to validate the Standard Model at highest
energies, and they may also open the door for the discovery of new physics
potentially showing up in subtle modifications of the non-abelian structure of
weak interactions. In this letter, we review the status of the corresponding
theory predictions, focusing on the higher-order electroweak corrections. We
present a NLO analysis of electroweak corrections to W-pair, W$^+$Z and Z-pair
production at the LHC, including all mass effects as well as leptonic decays.
Contributions of photon-induced processes and massive-boson radiation are also
discussed. The electroweak corrections are implemented in the HERWIG++ Monte
Carlo generator, where they are combined with QCD corrections. We also propose
a simple and straight-forward method allowing for an \emph{a posteriori}
implementation of electroweak corrections to vector-boson pair production in
any Monte Carlo event sample.


title: Optimal measurements in phase estimation: simple examples

abstract:
  We identify optimal measurement strategies for phase estimation in different
scenarios. For pure states of a single qubit, we show that optimal measurements
form a broad set parametrized with a continuous variable. When the state is
mixed this set reduces to merely two possible measurements. For two qubits, we
focus on the symmetric Werner state. We find an optimal measurement and show
that estimation from the population imbalance is optimal only if the state is
pure. Finally, for a pure state of $N$ qubits, we finds under which conditions
the estimation from the full $N$-body correlation and from the population
imbalance are optimal.


title: Benefits of multiple sites for asteroseismic detections

abstract:
  While Kepler has pushed the science of asteroseismology to limits
unimaginable a decade ago, the need for asteroseismic studies of individual
objects remains. This is primarily due to the limitations of single-colour
intensity variations, which are much less sensitive to certain asteroseismic
signals. The best way to obtain the necessary data is via very high resolution
ground-based spectrography. Such observations measure the perceived
radial-velocity shifts that arise due to stellar oscillations, which exhibit a
much better signal-to-noise ratio than those for intensity observations. SONG,
a proposed network of 1m telescopes with spectrographs that can reach
R=110,000, was designed with this need in mind. With one node under
commissioning in Tenerife and another under construction in China, an analysis
of the scientific benefits of constructing additional nodes for the network is
warranted. By convolving models of asteroseismic observables (mean densities,
small separations) with the anticipated window functions for different node
configurations, we explore the impact of the number of nodes in the SONG
network on the anticipated results, across the areas of the HR diagram where
solar-like oscillations are found. We find that although time series from two
SONG nodes, or in some cases even one node, will allow us to detect
oscillations, the full SONG network, providing full temporal coverage, is
needed for obtaining the science goals of SONG, including analysis of modes of
spherical harmonic degree l=3.


title: On realizations of the Virasoro algebra

abstract:
  We obtain complete classification of in-equivalent realizations of the
Virasoro algebra by Lie vector fields over the three-dimensional field of real
numbers. As an application we construct new classes of nonlinear second-order
partial differential equations possessing infinite-dimensional Lie symmetries.


title:
On the discontinuous Galerkin method for solving boundary value problems
  for the Helmholtz equation: A priori and a posteriori error analyses

abstract:
  We apply the local discontinuous Galerkin (LDG for short) method to solve a
mixed boundary value problems for the Helmholtz equation in bounded polygonal
domain in 2D. Under some assumptions on regularity of the solution of an
adjoint problem, we prove that: (a) the corresponding indefinite discrete
scheme is well posed; (b) there is convergence with the expected convergence
rates as long as the meshsize h is small enough. We give precise information on
how small h has to be in terms of the size of the wavenumber and its distance
to the set of eigenvalues for the same boundary value problem for the
Laplacian. We also present an a posteriori error estimator showing both the
reliability and efficiency of the estimator complemented with detailed
information on the dependence of the constants on the wavenumber. We finish
presenting extensive numerical experiments which illustrate the theoretical
results proven in this paper and suggest that stability and convergence may
occur under less restrictive assumptions than those taken in the present work.


title: Unitary embeddings of finite loop spaces

abstract:
  In this paper we construct faithful representations of saturated fusion
systems over discrete p-toral groups and use them to find conditions that
guarantee the existence of unitary embeddings of p-local compact groups. These
conditions hold for the Clark-Ewing and Aguad\'e-Zabrodsky p-compact groups as
well as some exotic 3-local compact groups. We also show the existence of
unitary embeddings of finite loop spaces.


title:
On the nature of WO stars: a quantitative analysis of the WO3 star DR1
  in IC 1613

abstract:
  Context. Oxygen sequence Wolf-Rayet (WO) stars are thought to represent the
final evolutionary stage of the most massive stars. The characteristic strong O
vi emission possibly originates from an enhanced oxygen abundance in the
stellar wind. Alternatively, the O vi emission can be caused by the high
temperature of these stars, in which case the WO stars are the high-temperature
extension of the more common carbon sequence Wolf-Rayet (WC) stars. Aims. By
constraining the physical properties and evolutionary status of DR1, a WO star
in the low-metallicity Local Group dwarf galaxy IC 1613 and one of only two
objects of its class known in a SMC-like metallicity environment, we aim to
investigate the nature of WO stars and their evolutionary connection with WC
stars. Methods. We use the non-LTE atmosphere code cmfgen to model the observed
spectrum of DR1 and to derive its stellar and wind parameters. We compare our
values with other studies of WC and WO stars, as well as with the predictions
of evolutionary models. We also model the surrounding nebula using the
photo-ionization code cloudy. Results. The oxygen and carbon abundances that we
obtain are comparable to values found for WC stars. The temperature and
luminosity are, however, higher than those of WC stars. DR1 is embedded in the
hottest known H ii region in the Local Group. The nebular properties can be
consistently reproduced by cloudy models adopting DR1 as central ionizing
source. Conclusions. Comparison of the abundances and temperature of DR1 with
core helium-burning models show that DR1 is currently well into the second half
of helium burning. If the properties of DR1 are representative for the WO
class, it would imply that WO stars are the high-temperature and
high-luminosity extension of the WC stars, and do not necessarily represent a
later evolutionary stage.


title:
Phenomenology of current-skyrmion interactions in thin films with
  perpendicular magnetic anisotropy

abstract:
  We study skyrmions in magnetic thin films with structural inversion asymmetry
perpendicular to the film plane. We determine the magnetization texture of a
single skyrmion and its dependence on the strength of the Dzyaloshinskii-Moriya
interaction relative to the magnetostatic energy. Furthermore, we construct a
phenomenological model that describes the interaction between the motion of
skyrmions and electric currents to lowest order in spin-orbit coupling. We
estimate the experimental verifiable velocities for current-driven motion of
skyrmion textures based on available results obtained from domain walls
dynamics.


title: Relative differential cohomology

abstract:
  We study two notions of relative differential cohomology, using the model of
differential characters. The two notions arise from the two options to
construct relative homology, either by cycles of a quotient complex or of a
mapping cone complex. We discuss the relation of the two notions of relative
differential cohomology to each other. We discuss long exact sequences for both
notions, thereby clarifying their relation to absolute differential cohomology.
We construct the external and internal product of relative and absolute
characters and show that relative differential cohomology is a right module
over the absolute differential cohomology ring. Finally we construct fiber
integration and transgression for relative differential characters.


title:
Using synthetic emission maps to constrain the structure of the Milky
  Way

abstract:
  We present the current standing of an investigation into the structure of the
Milky Way. We use smoothed particle hydrodynamics (SPH) to simulate the ISM gas
in the Milky Way under the effect of a number of different gravitational
potentials representing the spiral arms and nuclear bars, both fixed and
time-dependent. The gas is subject to ISM cooling and chemistry, enabling us to
track the CO and HI density. We use a 3D grid-based radiative transfer code to
simulate the emission from the SPH output, allowing for the construction of
synthetic longitude-velocity maps as viewed from the Earth. By comparing these
maps with the observed emission in CO and HI from the Milky Way (Dame et al.
2001, Kalberla et al. 2005), we can infer the arm/bar geometry that provides a
best fit to our Galaxy. By doing so we aim to answer key questions concerning
the morphology of the Milky Way such as the number of the spiral arms, the
pattern speeds of the bar(s) and arms, the pitch angle of the arms and shape of
the bar(s)


title:
Plasma heating in a post eruption Current Sheet: a case study based on
  ultraviolet, soft, and hard X-ray data

abstract:
  Off-limb observations of the solar corona after Coronal Mass Ejections (CMEs)
often show strong, compact, and persistent UV sources behind the eruption. They
are primarily observed by the SOHO/UVCS instrument in the "hot" Fe XVIII
{\lambda}974 {\AA} line and are usually interpreted as a signature of plasma
heating due to magnetic reconnection in the post-CME Current Sheet (CS).
Nevertheless, the physical process itself and the altitude of the main energy
release are currently not fully understood. In this work, we studied the
evolution of plasma heating after the CME of 2004 July 28 by comparing UV
spectra acquired by UVCS with soft X-ray (SXR) and hard X-ray (HXR)images of
the post-flare loops taken by GOES/SXI and RHESSI. The X-ray data show a
long-lasting extended source that is rising upwards, toward the
high-temperature source detected by UVCS. UVCS data show the presence of
significant non-thermal broadening in the CS (signature of turbulent motions)
and a strong density gradient across the CS region. The thermal energy released
in the HXR source is on the order of about 10^32 erg, a factor about 2-5 larger
than the energy required to explain the high-temperature plasma sampled by
UVCS. Nevertheless, the very different time evolutions of SXR and HXR sources
compared to the UV emission suggest that reconnection occurring above the
post-eruption arcades are not directly responsible for the high-temperature
plasma sampled higher up by UVCS. We conclude that an additional plasma heating
mechanism (such as turbulent reconnection) in the CS is likely required.


title: Ignition sequence of an annular multi-injector combustor

abstract:
  Ignition is a critical process in combustion systems. In aeronautical
combustors, altitude relight capacities are required in case of accidental
extinction of the chamber. A simultaneous study of light-round ignition in an
annular multi-injector combustor has been performed on the experimental and
numerical sides. This effort allows a unique comparison to assess the
reliability of Large-Eddy Simulation (LES) in such a configuration. Results are
presented in fluid dynamics videos.


title: Incompleteness of the Hamilton-Jacobi theory

abstract:
  The problem of the motion of a charged particle in an electric dipole field
is used to illustrate that the Hamilton-Jacobi method does not necessarily give
all solutions to the equations of motion of a mechanical system. The
mathematical reason for this phenomenon is discussed. In the particular case
under consideration, it is shown how to circumvent the difficulty and find the
missing solutions by means of a very special limiting procedure.


title: Quantum Subdivision Capacities and Continuous-time Quantum Coding

abstract:
  Quantum memories can be regarded as quantum channels that transmit
information through time without moving it through space. Aiming at a reliable
storage of information we may thus not only encode at the beginning and decode
at the end, but also intervene during the transmission - a possibility not
captured by the ordinary capacities in Quantum Shannon Theory. In this work we
introduce capacities that take this possibility into account and study them in
particular for the transmission of quantum information via dynamical semigroups
of Lindblad form. When the evolution is subdivided and supplemented by
additional continuous semigroups acting on arbitrary block sizes, we show that
the capacity of the ideal channel can be obtained in all cases. If the
supplementary evolution is reversible, however, this is no longer the case.
Upper and lower bounds for this scenario are proven. Finally, we provide a
continuous coding scheme and simple examples showing that adding a purely
dissipative term to a Liouvillian can sometimes increase the quantum capacity.


title: Intrinsically stable light source at telecom wavelengths

abstract:
  We present a highly stable light source at telecom wavelengths, based on a
short erbium doped fiber. The high stability arises from the high inversion of
the Er3+ion population. This source is developed to work as a stable reference
in radiometric applications and is useful in any application where high
stability and/or a large bandwidth are necessary. The achieved long-term
stability is 10 ppm.


title: Simple Dynamics for Plurality Consensus

abstract:
  We study a \emph{Plurality-Consensus} process in which each of $n$ anonymous
agents of a communication network initially supports an opinion (a color chosen
from a finite set $[k]$). Then, in every (synchronous) round, each agent can
revise his color according to the opinions currently held by a random sample of
his neighbors. It is assumed that the initial color configuration exhibits a
sufficiently large \emph{bias} $s$ towards a fixed plurality color, that is,
the number of nodes supporting the plurality color exceeds the number of nodes
supporting any other color by $s$ additional nodes. The goal is having the
process to converge to the \emph{stable} configuration in which all nodes
support the initial plurality. We consider a basic model in which the network
is a clique and the update rule (called here the \emph{3-majority dynamics}) of
the process is the following: each agent looks at the colors of three random
neighbors and then applies the majority rule (breaking ties uniformly).
  We prove that the process converges in time $\mathcal{O}( \min\{ k, (n/\log
n)^{1/3} \} \, \log n )$ with high probability, provided that $s \geqslant c
\sqrt{ \min\{ 2k, (n/\log n)^{1/3} \}\, n \log n}$.
  We then prove that our upper bound above is tight as long as $k \leqslant
(n/\log n)^{1/4}$. This fact implies an exponential time-gap between the
plurality-consensus process and the \emph{median} process studied by Doerr et
al. in [ACM SPAA'11].
  A natural question is whether looking at more (than three) random neighbors
can significantly speed up the process. We provide a negative answer to this
question: In particular, we show that samples of polylogarithmic size can speed
up the process by a polylogarithmic factor only.


title: On the anisotropic hyperdissipative Navier-Stokes equations

abstract:
  We consider the global Cauchy problem for the generalized incompressible
Navier- Stokes system in 3D whole space $$ u_t+u\cdot\nabla u+\nabla
p=\mathcal{A}_h u, $$ \begin{equation}\label{main0} \nabla\cdot u=0,
\end{equation} $$ u(x,0)=u_0(x), $$ where $u=(u_1, u_2, u_3)\in\mathbf{R}^3$
and $ p$ are the fluid velocity field and pressure. The initial data $u_0(x)$
is assumed to be smooth, rapidly decreasing and divergence free. Here
$\mathcal{A}_h$ is the anisotropic hyperdissipative operator. When
$\mathcal{A}_hu=-(-\Delta)^{5/4}$, it is called the critical case and the
global smooth solution exists. We consider the anisotropic operator with
$\mathcal{A}_hu= \left(\begin{array}{c} \partial_{x_1x_1} u_1+\partial_{x_2x_2}
u_1- M_3^{2\alpha} u_1 \\partial_{x_1x_1} u_2+\partial_{x_2x_2}
u_2-M_3^{2\alpha} u_2 \ - M_1^{2\gamma} u_3-M_2^{2\gamma} u_3-M_3^{2\alpha} u_3
\end{array} \right). $ and establish global regularity.


title:
Interactive Computation of Type-Threshold Functions in Collocated
  Broadcast-Superposition Networks

abstract:
  In wireless sensor networks, various applications involve learning one or
multiple functions of the measurements observed by sensors, rather than the
measurements themselves. This paper focuses on type-threshold functions, e.g.,
the maximum and indicator functions. Previous work studied this problem under
the collocated collision network model and showed that under many probabilistic
models for the measurements, the achievable computation rates converge to zero
as the number of sensors increases. This paper considers two network models
reflecting both the broadcast and superposition properties of wireless
channels: the collocated linear finite field network and the collocated
Gaussian network. A general multi-round coding scheme exploiting not only the
broadcast property but particularly also the superposition property of the
networks is developed. Through careful scheduling of concurrent transmissions
to reduce redundancy, it is shown that given any independent measurement
distribution, all type-threshold functions can be computed reliably with a
non-vanishing rate in the collocated Gaussian network, even if the number of
sensors tends to infinity.


title:
Distributed firewalls and IDS interoperability checking based on a
  formal approach

abstract:
  To supervise and guarantee a network security, the administrator uses
different security components, such as firewalls, IDS and IPS. For a perfect
interoperability between these components, they must be configured properly to
avoid misconfiguration between them. Nevertheless, the existence of a set of
anomalies between filtering rules and alerting rules, particularly in
distributed multi-component architectures is very likely to degrade the network
security. The main objective of this paper is to check if a set of security
components are interoperable. A case study using a firewall and an IDS as
examples will illustrate the usefulness of our approach.


title: Discrete mechanics, time machines and hybrid systems

abstract:
  Modifying the discrete mechanics proposed by T.D. Lee, we construct a class
of discrete classical Hamiltonian systems, in which time is one of the
dynamical variables. This includes a toy model of time machines which can
travel forward and backward in time and which differ from models based on
closed timelike curves (CTCs). In the continuum limit, we explore the
interaction between such time reversing machines and quantum mechanical
objects, employing a recent description of quantum-classical hybrids.


title: Spin entanglement and nonlocality of multifermion systems

abstract:
  Spin density matrices of the system, containing arbitrary even number N of
indistinguishable fermions with spin S = 1/2, described by antisymmetric wave
function, have been calculated. The indistinguishability and the Pauli
principles are proved to determine uniquely spin states, spin correlations and
entanglement of fermion spin states. Increase of the particle number in the
multifermion system reduces the spin correlation in any pair of fermions. The
fully entangled system of N electrons are shown to be composed by pairs with
nonentangled spin states that is the incoherent superposition of the singlet
and triplet states. Any large system of N fermions, such as electrons with spin
S = 1/2, the spin state of any particle are shown to be entangled with the
other part of the system containing N-1 particle. However, the spin state of
this electron is not entangled with any other particle, and spin state of any
electron pair is not entangled. These properties of spin states manifest in the
Einstein-Podolsky-Rosen as confirmation or violation of the Bell inequalities
indicating the presence of non-local quantum spin correlations.


title: Virtual Location-Based Services: Merging the Physical and Virtual World

abstract:
  Location-based services gained much popularity through providing users with
helpful information with respect to their current location. The search and
recommendation of nearby locations or places, and the navigation to a specific
location are some of the most prominent location-based services. As a recent
trend, virtual location-based services consider webpages or sites associated
with a location as 'virtual locations' that online users can visit in spite of
not being physically present at the location. The presence of links between
virtual locations and the corresponding physical locations (e.g., geo-location
information of a restaurant linked to its website), allows for novel types of
services and applications which constitute virtual location-based services
(VLBS). The quality and potential benefits of such services largely depends on
the existence of websites referring to physical locations. In this paper, we
investigate the usefulness of linking virtual and physical locations. For this,
we analyze the presence and distribution of virtual locations, i.e., websites
referring to places, for two Irish cities. Using simulated tracks based on a
user movement model, we investigate how mobile users move through the Web as
virtual space. Our results show that virtual locations are omnipresent in urban
areas, and that the situation that a user is close to even several such
locations at any time is rather the normal case instead of the exception.


title: Interpenetration of matter in plate theories obtained as Gamma-limits

abstract:
  We consider a potential pathology in the derivation of plate theories as
Gamma-limits of 3-dimensional nonlinear elasticity by Friesecke James and
Muller (Comm. Pure Appl. Math., 55:1461-1506 and Arch. Ration. Mech. Anal.,
180:183-236), which consists in recovery sequences of invertible maps that
converge to a non-invertible limit. These pathologies have been noted by Muller
and Spector (Arch. Ration. Mech. Anal. 131:1-66) in a different context. Using
a combination of degree theory, the approximation of Sobolev functions by
Lipschitz functions and geometric rigidity we show that the potentially
pathological situation in the derivation of plate theories provides sufficient
conditions for the self-intersection of the graph of the recovery sequence
element, and thus the pathology is excluded.


title:
IR properties of one loop corrections to brane-to-brane propagators in
  models with localized vector bosons

abstract:
  We discuss the one loop effects of massless fermion fields on the low energy
vector brane-to-brane propagators in the framework of two QED brane-world
scenarios. We show that one loop photon brane-to-brane propagator has a power
law pathologic IR divergences in the 5D QED brane-world model with gap between
the vector zero mode and continuous states. We also find that bulk fermions do
not give rise to IR divergences in a photon brane-to-brane Green's function at
least at the one loop level in the framework of 6D QED brane model with gapless
mass spectrum between vector zero mode and higher states.


title:
The Existence of Strong Solutions to the 3D Zakharov-Kuznestov Equation
  in a Bounded Domain

abstract:
  We consider the Zakharov-Kuznestov (ZK) equation posed in a limited domain
(0,1)_{x}\times(-\pi /2, \pi /2)^d, d=1,2 supplemented with suitable boundary
conditions. We prove that there exists a solution u \in \mathcal C ([0, T];
H^1(\dom)) to the initial and boundary value problem for the ZK equation in
both dimensions 2 and 3 for every T>0.
  To the best of our knowledge, this is the first result of the global
existence of strong solutions for the ZK equation in 3D.
  More importantly, the idea behind the application of anisotropic estimation
to cancel the nonlinear term, we believe, is not only suited for this model but
can also be applied to other nonlinear equations with similar structures.
  At the same time, the uniqueness of solutions is still open in 2D and 3D due
to the partially hyperbolic feature of the model.


title: Application of Quantum Field Theory

abstract:
  In this paper we will analyse some interesting structures that occur in
scalar quantum field theory. We will quantize this theory using path integrals.
We will analyse the Bogomolny Bound for scalar quantum field theory in two
dimensions. We will also analyse the generalization of this result to
fractional powers of the differential operator.


title: The spectral gap of graphs and Steklov eigenvalues on surfaces

abstract:
  Using expander graphs, we construct a sequence of smooth compact surfaces
with boundary of perimeter N, and with the first non-zero Steklov eigenvalue
uniformly bounded away from zero. This answers a question which was raised in
[9]. The genus grows linearly with N, this is the optimal growth rate.


title:
The spectral index image of the radio halo in the cluster Abell 520
  hosting a famous bow shock

abstract:
  Synchrotron radio emission is being detected from an increasing number of
galaxy clusters. Spectral index images are a powerful tool to investigate the
origin, nature, and connection of these sources with the dynamical state of the
cluster. The aim of this work is to investigate the spectral index distribution
of the radio halo in the galaxy cluster A520, a complex system from an optical,
radio, and X-ray point of view. We present deep Very Large Array observations
in total intensity at 325 and 1400 MHz. We produced and analyzed spectral index
images of the radio halo in this frequency range at a resolution of 39" and 60"
and looked for possible correlations with the thermal properties of the
cluster. We find an integrated radio halo spectral index alpha(325-1400) ~
1.12. No strong radial steepening is present and the spectral index
distribution is intrinsically complex with fluctuations only partially due to
measurement errors. The radio halo integrated spectral index and the cluster
temperature follow the global trend observed in other galaxy clusters although
a strong point-to-point correlation between the spectral index and the thermal
gas temperature has not been observed. The complex morphology in the spectral
index image of the radio halo in A520 is in agreement with the primary models
for radio halo formation. The flatness of the radial profile suggests that the
merger is still ongoing and is uniformly and continuously (re-) accelerating
the population of relativistic electrons responsible of the radio emission even
at large (~ 1 Mpc) distances from the cluster center.


title:
Gravitational wave detector response in terms of spacetime Riemann
  curvature

abstract:
  Gravitational wave detectors are typically described as responding to
gravitational wave metric perturbations, which are gauge-dependent and ---
correspondingly --- unphysical quantities. This is particularly true for
ground-based interferometric detectors, like LIGO, space-based detectors, like
LISA and its derivatives, spacecraft doppler tracking detectors, and pulsar
timing arrays detectors. The description of gravitational waves, and a
gravitational wave detector's response, to the unphysical metric perturbation
has lead to a proliferation of false analogies and descriptions regarding how
these detectors function, and true misunderstandings of the physical character
of gravitational waves.
  Here we provide a fully physical and gauge invariant description of the
response of a wide class of gravitational wave detectors in terms of the
Riemann curvature, the physical quantity that describes gravitational phenomena
in general relativity. In the limit of high frequency gravitational waves, the
Riemann curvature separates into two independent gauge invariant quantities: a
"background" curvature contribution and a "wave" curvature contribution. In
this limit the gravitational wave contribution to the detector response reduces
to an integral of the gravitational wave contribution of the curvature along
the unperturbed photon path between components of the detector. The description
presented here provides an unambiguous physical description of what a
gravitational wave detector measures and how it operates, a simple means of
computing corrections to a detectors response owing to general detector motion,
a straightforward way of connecting the results of numerical relativity
simulations to gravitational wave detection, and a basis for a general and
fully relativistic pulsar timing formula.


title: A new construction for Cohen-Macaulay graphs

abstract:
  Let $G$ be a finite simple graph on a vertex set $V(G)=\{x_{11}, \ldots,
x_{n1}\}$. Also let $m_1, \ldots,m_n \geq 2$ be integers and $G_1, \ldots, G_n$
be connected simple graphs on the vertex sets $V(G_i)=\{x_{i1}, \ldots,
x_{im_i}\}$. In this paper, we provide necessary and sufficient conditions on
$G_1, \ldots, G_n$ for which the graph obtained by attaching $G_i$ to $G$ is
unmixed or vertex decomposable. Then we characterize Cohen--Macaulay and
sequentially Cohen--Macaulay graphs obtained by attaching the cycle graphs or
connected chordal graphs to an arbitrary graphs.


title: Regional variance for multi-object filtering

abstract:
  Recent progress in multi-object filtering has led to algorithms that compute
the first-order moment of multi-object distributions based on sensor
measurements. The number of targets in arbitrarily selected regions can be
estimated using the first-order moment. In this work, we introduce explicit
formulae for the computation of the second-order statistic on the target
number. The proposed concept of regional variance quantifies the level of
confidence on target number estimates in arbitrary regions and facilitates
information-based decisions. We provide algorithms for its computation for the
Probability Hypothesis Density (PHD) and the Cardinalized Probability
Hypothesis Density (CPHD) filters. We demonstrate the behaviour of the regional
statistics through simulation examples.


title: Signs of Phase Transitions in Two-Nucleon Systems

abstract:
  The properties of dense nuclear matter under extreme conditions are a subject
of the large experimental activities worldwide. Heavy-ion collision experiments
are the agenda item at RHIC, LHC, FAIR, and NICA facilities. Meanwhile, a
complementary approach to the heavy-ion collision researches devoted to
investigation of phase transitions in few-nucleon systems has not been
discussed. In this paper, we try to fill up the gap. It is shown that signals
of the phase transition of deuteron into 6-q bag as well as signs of formation
of the pion Bose condensate in compressed two-nucleon systems might be already
observed in deuteron-deuteron collisions.


title: Vacuum instability by a chromoelectric field in 2 + 1-dimensions

abstract:
  The problem of vacuum instability and creation of pairs by external fields
SU(2) is studied. The effective mass operator has complex eigenvalues implying
decay and pair creation. We consider a constant external chromoelectric field
and a region in the parameter space where the vaccum becomes unstable and
decays in pairs. Although the calculation is done in SU(2) color group it is
also valid for SU(3).


title: Squeezing through: capsule or bubble?

abstract:
  In this fluid dynamics video, we compare the deformation of two flexible
particles as they propagate through a sudden constriction of a liquid filled
channel under constant-flux flow: a gas bubble, and a capsule formed by
encapsulating a liquid droplet in a cross-linked polymeric membrane. Both
bubble and capsule adopt highly contorted configurations as they squeeze
through the constriction, exhibit broadly similar features over a wide range of
flow rates, and rupture for sufficiently high flow rates. However, at flow
rates prior to rupture, certain features of the deformation allow bubble and
capsule to be distinguished: bubbles exhibit a tip-streaming singularity
associated with critical thinning of the rear of the bubble, while the capsule
membrane wrinkles under large compressive stresses induced by the constriction.


title: A functorial control of integral torsion in homology

abstract:
  We study the integral torsion of the values of strict polynomial functors
defined over the integers. We interpret some classical homological invariants
as values of strict polynomial functors and therefore obtain estimates of the
integral torsion of these invariants, including cancellation results.


title: Dimensional curvature identities on pseudo-Riemannian geometry

abstract:
  The curvature tensor of a pseudo-Riemannian metric, and its covariant
derivatives, satisfy certain identities that hold on any manifold of dimension
less or equal than $n$.
  In this paper, we re-elaborate recent results by Gilkey-Park-Sekigawa
regarding $p$-covariant dimensional curvature identities, for $p=0,2$. To this
end, we use the classical theory of natural operations, that allows us to
simplify some arguments and to generalize the description of
Gilkey-Park-Sekigawa.
  Thus, our main result describes the first space of $p$-covariant dimensional
curvature identities, for any even $p$.


title:
Mechanical Controlled Thermal Switch and Hysteresis with Domain Boundary
  Engineered Phonon Transport

abstract:
  Heat flow control in phononics has received significant attention recently
due to its widespread applications in energy transfer, conversion and
utilization. Here, we demonstrate that by applying external stress or strain we
can effectively tune the thermal conductivity through changing the density of
twin boundaries, which in turn offers the intriguing mechanical-controlled
thermal switch and hysteresis operations. Twin boundaries perpendicular to the
transport direction strongly scatter phonons. As such, the heat flow is in
inverse proportional to the density of twin boundaries and hence allows an
excellent way to switch thermal conductivity mechanically and even leads to the
interesting hysteresis behavior as a thermal memory. Our study provides a novel
mechanism to couple thermal and mechanical properties of materials as a matter
of "domain boundary engineering" and can have substantial implications in
flexible thermal control and thermal energy harvesting.


title:
Feature Selection with Annealing for Computer Vision and Big Data
  Learning

abstract:
  Many computer vision and medical imaging problems are faced with learning
from large-scale datasets, with millions of observations and features. In this
paper we propose a novel efficient learning scheme that tightens a sparsity
constraint by gradually removing variables based on a criterion and a schedule.
The attractive fact that the problem size keeps dropping throughout the
iterations makes it particularly suitable for big data learning. Our approach
applies generically to the optimization of any differentiable loss function,
and finds applications in regression, classification and ranking. The resultant
algorithms build variable screening into estimation and are extremely simple to
implement. We provide theoretical guarantees of convergence and selection
consistency. In addition, one dimensional piecewise linear response functions
are used to account for nonlinearity and a second order prior is imposed on
these functions to avoid overfitting. Experiments on real and synthetic data
show that the proposed method compares very well with other state of the art
methods in regression, classification and ranking while being computationally
very efficient and scalable.


title: Central exclusive J/{\psi} and {\chi}c production at LHCb

abstract:
  Central exclusive J/{\psi} and {\chi}c meson production has been measured in
decays to dimuons with the LHCb detector, in data corresponding to 36 /pb of
integrated luminosity from \sqrt{s} = 7 TeV proton-proton collisions.
Cross-section measurements for J/{\psi}, {\psi}(2S) and {\chi}c0,c1,c2
production are presented, and the J/{\psi} photoproduction cross-section is
measured as a function of the photon-proton centre-of-mass energy and compared
to measurements made at HERA.


title:
Informational Divergence and Entropy Rate on Rooted Trees with
  Probabilities

abstract:
  Rooted trees with probabilities are used to analyze properties of a variable
length code. A bound is derived on the difference between the entropy rates of
the code and a memoryless source. The bound is in terms of normalized
informational divergence. The bound is used to derive converses for exact
random number generation, resolution coding, and distribution matching.


title: Deconstructing wall turbulence -visualization of resolvent modes

abstract:
  This article accompanies a fluid dynamics video entered into the Gallery of
Fluid Motion of the 66th Annual Meeting of the APS Division of Fluid Dynamics.


title: The Superconducting Quantum Interference Proximity Transistor (SQUIPT)

abstract:
  In this article we review the basic theoretical properties of a hybrid
superconducting interferometer which exploits the phase dependence of the
density of states of a metallic nanowire placed in good electric contact with a
superconductor to achieve high sensitivity to magnetic flux. The operation of a
prototype structure based on this principle, the superconducting quantum
interference proximity transistor (SQUIPT), has been recently reported. Limited
power dissipation joined with the opportunity to access single-spin detection
make this interferometer attractive for the investigation of the switching
dynamics of individual magnetic nanoparticles. The noise behavior of the device
is presented as well, where the feasibility of this structure as a single-spin
detector is also briefly addressed. In the final part we present the response
of a real SQUIPT device.


title:
A quantum lower bound for distinguishing random functions from random
  permutations

abstract:
  The problem of distinguishing between a random function and a random
permutation on a domain of size $N$ is important in theoretical cryptography,
where the security of many primitives depend on the problem's hardness. We
study the quantum query complexity of this problem, and show that any quantum
algorithm that solves this problem with bounded error must make
$\Omega(N^{1/5}/\log N)$ queries to the input function. Our lower bound proof
uses a combination of the Collision Problem lower bound and Ambainis's
adversary theorem.


title: Emergency and Normal Navigation in Confined Spaces

abstract:
  Emergency navigation algorithms direct evacuees to exits when disastrous
events such as fire take place. Due to the spread of hazards, latency in
information updating and unstable flows of civilians, emergency evacuation is
absolutely a complex transshipment problem involving numerous sources and
multiple destinations. Previous algorithms which commonly need either a full
graph search or a convergence process suffer from high computational and
communication overheads. This research report surveys the current emergency
navigation algorithms and adapts the concept of Cognitive Packet Network (CPN)
to the context of emergency evacuation. By using random neural networks, the
CPN based algorithm can explore optimal routes rapidly and adaptively in a
highly dynamic emergency environment with low expense. Simultaneously, in
emergency situations there are typically different categories of evacuees such
as people of different age groups. However, current algorithms only consider
"normal" evacuees and do not meet the specific requirements of diverse
evacuees. Our algorithms make use of the flexibility of CPN which can operate
with different user-defined goals to customize appropriate paths for each
category. The CPN algorithm is simulated in a graph based discrete-event
simulator and Dijkstra's shortest path algorithm is taken as reference. The
results show that the CPN algorithm reaches the performance of ideal
path-finding algorithm and quality of service is improved by using specific
goal functions for diverse categories of evacuees. Finally, we present a future
plan for further research.


title: An Accelerated Randomized Kaczmarz Algorithm

abstract:
  The randomized Kaczmarz ($\RK$) algorithm is a simple but powerful approach
for solving consistent linear systems $Ax=b$. This paper proposes an
accelerated randomized Kaczmarz ($\ARK$) algorithm with better convergence than
the standard $\RK$ algorithm on ill conditioned problems. The per-iteration
cost of $\RK$ and $\ARK$ are similar if $A$ is dense, but $\RK$ is much more
able to exploit sparsity in $A$ than is $\ARK$. To deal with the sparse case,
an efficient implementation for $\ARK$, called $\SARK$, is proposed. A
comparison of convergence rates and average per-iteration complexities among
$\RK$, $\ARK$, and $\SARK$ is given, taking into account different levels of
sparseness and conditioning. Comparisons with the leading deterministic
algorithm --- conjugate gradient applied to the normal equations --- are also
given. Finally, the analysis is validated via computational testing.


title:
Transdimensional Approximate Bayesian Computation for Inference on
  Invasive Species Models with Latent Variables of Unknown Dimension

abstract:
  Accurate information on patterns of introduction and spread of non-native
species is essential for making predictions and management decisions. In many
cases, estimating unknown rates of introduction and spread from observed data
requires evaluating intractable variable-dimensional integrals. In general,
inference on the large class of models containing latent variables of large or
variable dimension precludes exact sampling techniques. Approximate Bayesian
computation (ABC) methods provide an alternative to exact sampling but rely on
inefficient conditional simulation of the latent variables. To accomplish this
task efficiently, a new transdimensional Monte Carlo sampler is developed for
approximate Bayesian model inference and used to estimate rates of introduction
and spread for the non-native earthworm species Dendrobaena octaedra (Savigny)
along roads in the boreal forest of northern Alberta. Using low and high
estimates of introduction and spread rates, the extent of earthworm invasions
in northeastern Alberta was simulated to project the proportion of suitable
habitat invaded in the year following data collection.


title:
Isospin violation in the yield of S-wave heavy meson pairs near
  threshold

abstract:
  We consider production of overall neutral pairs consisting of heavy $D^{(*)}$
or $B^{(*)}$ meson and antimeson in the processes, where the pair can be
created in an $S$-wave, such as $e^+e^- \to \pi^0 \, D^* \bar D^{(*)}$ and
$e^+e^- \to \gamma \, D^{(*)} \bar D^{(*)}$, and similar reactions with
$B^{(*)}$ mesons. The ratio $R^{c/n}$ of the yield of pairs of charged mesons
to that of neutral mesons near the threshold for the heavy pair is strongly
affected by the isospin breaking due to the isotopic mass differences and due
to the Coulomb interaction between the charged mesons. The actual behavior of
the isospin breaking in $R^{c/n}$ is also sensitive to the strong interaction
between the heavy mesons, so that experimental measurement of this ratio can be
used as a probe of this strong interaction. We calculate $R^{c/n}$ at and very
near the threshold in terms of the isotopic scattering lengths for the meson
pairs. In particular we find that the yield of pairs of charged mesons does not
go to zero at exactly the threshold, but rather starts with a finite step,
whose height depends on the value of the scattering length in a particular
channel.


title: Einstein and the conservation of energy-momentum in general relativity

abstract:
  The main purpose of the present paper is to show that a correction of one
mistake was crucial for Einstein's pathway to the first version of the 1915
general theory of relativity, but also might have played a role in obtaining
the final version of Einstein's 1915 field equations. In 1914 Einstein wrote
the equations for conservation of energy-momentum for matter, and established a
connection between these equations and the components of the gravitational
field. He showed that a material point in gravitational fields moves on a
geodesic line in space-time, the equation of which is written in terms of the
Christoffel symbols. By November 4, 1915, Einstein found it advantageous to use
for the components of the gravitational field, not the previous equation, but
the Christoffel symbols. He corrected the 1914 equations of conservation of
energy-momentum for matter. Einstein had already basically possessed the field
equations in 1912 together with his mathematician friend Marcel Grossman, but
because he had not recognized the formal importance of the Christoffel symbols
as the components of the gravitational field, he could "not obtain a clear
overview". Finally, considering the energy-momentum conservation equations for
matter, an important similarity between equations suggests that, this equation
could have assisted Einstein in obtaining the final form of the field equations
(the November 25, 1915 ones) that were generally covariant.


title:
Stochastic thermodynamics of fluctuating density fields: Non-equilibrium
  free energy differences under coarse-graining

abstract:
  We discuss the stochastic thermodynamics of systems that are described by a
time-dependent density field, for example simple liquids and colloidal
suspensions. For a time-dependent change of external parameters, we show that
the Jarzynski relation connecting work with the change of free energy holds if
the time evolution of the density follows the Kawasaki-Dean equation.
Specifically, we study the work distributions for the compression and expansion
of a two-dimensional colloidal model suspension implementing a practical
coarse-graining scheme of the microscopic particle positions. We demonstrate
that even if coarse-grained dynamics and density functional do not match, the
fluctuation relations for the work still hold albeit for a different, apparent,
change of free energy.


title:
Approximation Rates for Interpolation of Sobolev Functions via Gaussians
  and Allied Functions

abstract:
  A \Riesz-basis sequence for $L_2[-\pi,\pi]$ is a strictly increasing sequence
$X:=(x_j)_{j\in\mathbb{Z}}$ in $\mathbb{R}$ such that the set of functions
$\left(e^{-ix_j(\cdot)}\right)_{j\in\mathbb{Z}}$ is a Riesz basis for
$L_2[-\pi,\pi]$. Given such a sequence and a parameter $0<h\leq1$, we consider
interpolation of functions $g\in W_2^k(\mathbb{R})$ at the set
$(hx_j)_{j\in\mathbb{Z}}$ via translates of the Gaussian kernel. Existence is
shown of an interpolant of the form
$$I^{hX}(g)(x):=\underset{j\in\mathbb{Z}}{\sum}a_je^{-(x-hx_j)^2},\quad
x\in\mathbb{R},$$ which is continuous and square-integrable on $\mathbb{R}$,
and satisfies the interpolatory condition
$I^{hX}(g)(hx_j)=g(hx_j),j\in\mathbb{Z}$. Moreover, use of the parameter $h$
gives approximation rates of order $h^k$. Namely, there is a constant
independent of $g$ such that $\|I^{hX}(g)-g\|_{L_2(\mathbb{R})}\leq
Ch^k|g|_{W_2^k(\mathbb{R})}$. Interpolation using translates of certain
functions other than the Gaussian, so-called regular interpolators, is also
considered and shown to exhibit the same approximation rates.


title: Extracting Effective Higgs Couplings in the Golden Channel

abstract:
  Kinematic distributions in Higgs decays to four charged leptons, the so
called `golden channel, are a powerful probe of the tensor structure of its
couplings to neutral electroweak gauge bosons. In this study we construct the
first part of a comprehensive analysis framework designed to maximize the
information contained in this channel in order to perform direct extraction of
the various possible Higgs couplings. To that end we first complete an earlier
analytic calculation of the leading order fully differential cross sections for
the golden channel signal and background to include the 4e and $4\mu$ final
states with interference between identical final states. We also examine the
relative fractions of the different possible combinations of scalar-tensor
couplings by integrating the fully differential cross section over all
kinematic variables as well as show various doubly differential spectra for
both the signal and background. From these analytic expressions we then
construct a `generator level' analysis framework based on the maximum
likelihood method. We demonstrate the ability of our framework to perform
multi-parameter extractions of all the possible effective couplings of a spin-0
scalar to pairs of neutral electroweak gauge bosons including any correlations.
This framework provides a powerful method for study of these couplings and can
be readily adapted to include the relevant detector and systematic effects
which we demonstrate in an accompanying study to follow.


title: Integer Complexity and Well-Ordering

abstract:
  Define $\|n\|$ to be the complexity of $n$, the smallest number of ones
needed to write $n$ using an arbitrary combination of addition and
multiplication. John Selfridge showed that $\|n\| \ge 3\log_3 n$ for all $n$.
Define the defect of $n$, denoted $\delta(n)$, to be $\|n\| - 3\log_3 n$. In
this paper, we consider the set $\mathscr{D} := \{\delta(n): n \ge 1 \}$ of all
defects. We show that as a subset of the real numbers, the set $\mathscr{D}$ is
well-ordered, of order type $\omega^\omega$. More specifically, for $k\ge 1$ an
integer, $\mathscr{D}\cap[0,k)$ has order type $\omega^k$. We also consider
some other sets related to $\mathscr{D}$, and show that these too are
well-ordered and have order type $\omega^\omega$.


title:
Delay differential equation models for single and coupled bubble
  dynamics in a compressible liquid

abstract:
  Various models for interacting spherical bubbles in a compressible liquid
based on delay differential equations are considered. It is shown that most
previously proposed models for interacting spherical bubbles in a compressible
liquid based on the Keller-Miksis and Gilmore-Akulichev models are unstable for
closely spaced bubbles. A new model for a single spherical bubble in a
compressible liquid is proposed and used to derive a stable model for
interacting bubbles. A qualitative comparison to the results of direct
numerical integration of the fluid equations of motion suggests that the new
model provides more accurate results than the standard Keller-Miksis or
Gilmore-Akulichev models for single bubble dynamics.


title: Flow probe of symmetry energy in relativistic heavy-ion reactions

abstract:
  Flow observables in heavy-ion reactions at incident energies up to about 1
GeV per nucleon have been shown to be very useful for investigating the
reaction dynamics and for determining the parameters of reaction models based
on transport theory. In particular, the elliptic flow in collisions of
neutron-rich heavy-ion systems emerges as an observable sensitive to the
strength of the symmetry energy at supra-saturation densities. The comparison
of ratios or differences of neutron and proton flows or neutron and hydrogen
flows with predictions of transport models favors an approximately linear
density dependence, consistent with ab-initio nuclear-matter theories.
Extensive parameter searches have shown that the model dependence is comparable
to the uncertainties of existing experimental data. Comprehensive new flow data
of high accuracy, partly also through providing stronger constraints on model
parameters, can thus be expected to improve our knowledge of the equation of
state of asymmetric nuclear matter.


title:
A Classification of the Veldkamp Lines of the Near Hexagon L_3 times
  GQ(2, 2)

abstract:
  Using a standard technique sometimes (inaccurately) known as Burnside's
Lemma, it is shown that the Veldkamp space of the near hexagon L_3 times GQ(2,
2) features 156 different types of lines. We also give an explicit description
of each type of a line by listing the types of the three geometric hyperplanes
it consists of and describing the properties of its core set, that is the
subset of points of L_3 times GQ(2, 2) shared by the three geometric
hyperplanes in question.


title: Parametric pattern selection in a reaction-diffusion model

abstract:
  We compare spot patterns generated by Turing mechanisms with those generated
by replication cascades, in a model one-dimensional reaction-diffusion system.
We determine the stability region of spot solutions in parameter space as a
function of a natural control parameter (feed-rate) where degenerate patterns
with different numbers of spots coexist for a fixed feed-rate. While it is
possible to generate identical patterns via both mechanisms, we show that
replication cascades lead to a wider choice of pattern profiles that can be
selected through a tuning of the feed-rate, exploiting hysteresis and
directionality effects of the different pattern pathways.


title: Periodic magnetic curves in elliptic Sasakian space forms

abstract:
  It is an interesting question whether a given equation of motion has a
periodic solution or not, and in the positive case to describe them. We
investigate periodic magnetic curves in elliptic Sasakian space forms and we
obtain a quantization principle for periodic magnetic flowlines on Berger
spheres. We give a criterion for periodicity of magnetic curves on the unit
sphere ${\mathbb{S}}^3$.


title: Noncommutative Ricci flow in a matrix geometry

abstract:
  We study noncommutative Ricci flow in a finite dimensional representation of
a noncommutative torus. It is shown that the flow exists and converges to the
flat metric. We also consider the evolution of entropy and a definition of
scalar curvature in terms of the Ricci flow.


title: 2-connected claw-free chordal graphs are cycle extendable

abstract:
  A cycle $C$ of length $k$ in graph $G$ is extendable if there is another
cycle $C'$ in $G$ with $V(C) \subset V(C')$ and length $k+1$. A graph is cycle
extendable if every non-Hamiltonian cycle is extendable. In 1990 Hendry
conjectured that any Hamiltonian chordal graph (a Hamiltonian graph with no
induced cycle of length greater than three) is cycle extendable, and this
conjecture has been verified for Hamiltonian chordal graphs which are interval
graphs, planar graphs, and split graphs. We prove that any 2-connected
claw-free chordal graph is cycle extendable.


title:
Dynamics of second order in time evolution equations with
  state-dependent delay

abstract:
  We deal with a class of second order in time nonlinear evolution equations
with state-dependent delay. This class covers several important PDE models
arising in the theory ofnonlinear plates. Our first result states
well-posedness in a certain space of functions which are C1 in time. In
contrast with the first order models with discrete state-dependent delay this
result does not require any compatibility conditions. The solutions constructed
generate a dynamical system in a C1-type space over delay time interval. Our
next result shows that this dynamical system possesses compact global and
exponential attractors of finite fractal dimension. To obtain this result we
adapt the recently developed method of quasi-stability estimates.


title: Extremal Betti numbers of some classes of binomial edge ideals

abstract:
  Let $G$ be a cycle or a complete bipartite graph. We show that the binomial
edge ideal $J_{G}$ and its initial ideal with respect to the lexicographic
order have the same extremal Betti number.


title: Coupling of the Local Defect and Magnetic Structure of Wustite, Fe1-xO

abstract:
  The local nuclear and magnetic structure of wustite, Fe1-xO, and the coupling
between them, has been examined using reverse Monte Carlo refinements of
variable-temperature neutron total scattering data. The results from this
analysis suggest that the individual units in a tetrahedral defect cluster are
connected along <110> vectors into a Koch-Cohen-like arrangement, with the
majority of octahedral vacancies concentrated near these defects. Bond valence
calculations indicate a change in the charge distribution on the cations with
the charge on the tetrahedral interstitials increasing on cooling. The magnetic
structure is more complex than previously thought, corresponding to a
non-collinear spin arrangement described by a superposition of a condensed spin
wave on the established type-II antiferromagnetic ordering. This leads to an
architecture with four groups of cations each with different spin directions.
The cations within the interstitial clusters appear to be weakly
ferromagnetically coupled and their spins are correlated to the spins of the
octahedral cations closest to them. This work not only provides further insight
into the local structure of wustite but also a better understanding of the
coupling between defect structures and magnetic and charge-ordering in complex
materials.


title:
Two discussions of the paper "Bayesian measures of model complexity and
  fit" by D. Spiegelhalter et al., Read before The Royal Statistical Society at
  a meeting organized by the Research Section on Wednesday, March 13th, 2002

abstract:
  These are the written discussions of the paper "Bayesian measures of model
complexity and fit" by D. Spiegelhalter et al. (2002), following the
discussions given at the Annual Meeting of the Royal Statistical Society in
Newcastle-upon-Tyne on September 3rd, 2013.


title:
Brain temperature: what it means and what it can do for (cognitive)
  neuroscientists

abstract:
  The effects of temperature on various aspects of neural activity from single
cell to neural circuit level have long been known. However, how temperature
affects the system-level of activity typical of experiments using non-invasive
imaging techniques, such as magnetic brain imaging of electroencephalography,
where neither its direct measurement nor its manipulation are possible, is
essentially unknown. Starting from its basic physical definition, we discuss
possible ways in which temperature may be used both as a parameter controlling
the evolution of other variables through which brain activity is observed, and
as a collective variable describing brain activity. These two aspects are
further illustrated in the case of learning-related brain activity. Finally,
methods to extract a temperature from experimental data are reviewed.


title:
Representations of 3-manifold groups in PGL(n,C) and their restriction
  to the boundary

abstract:
  We study here the space of representations of a fundamental group of a
3-manifold into PGL(n,C). Thurston, Neumann and Zagier initiated a strategy (in
the case of PGL(2,C)) consisting in: triangulate the manifold, assign shapes to
each pieces and then try to glue back. This leads to the "gluing equations" and
the Neumann-Zagier symplectic space.
  Building on the works of Dimofte-Gabella-Goncharov and
Bergeron-Falbel-Guilloux, we complete the picture in the case of PGL(n,C). We
recover a situation very similar to the case of PGL(2,C). This allows for
example to obtain a combinatorial proof of a local rigidity results for such
representations.


title: Performance of the TOTEM Detectors at the LHC

abstract:
  The TOTEM Experiment is designed to measure the total proton-proton
cross-section with the luminosity-independent method and to study elastic and
diffractive pp scattering at the LHC. To achieve optimum forward coverage for
charged particles emitted by the pp collisions in the interaction point IP5,
two tracking telescopes, T1 and T2, are installed on each side of the IP in the
pseudorapidity region 3.1 < = |eta | < = 6.5, and special movable beam-pipe
insertions - called Roman Pots (RP) - are placed at distances of +- 147 m and
+- 220 m from IP5. This article describes in detail the working of the TOTEM
detector to produce physics results in the first three years of operation and
data taking at the LHC.


title:
Use of Homotopy Perturbation Method for Solving Multi-point Boundary
  Value Problems

abstract:
  Homotopy perturbation method is used for solving the multi-point boundary
value problems. The approximate solution is found in the form of a rapidly
convergent series. Several numerical examples have been considered to
illustrate the efficiency and implementation of the method and the results are
compared with the other methods in the literature.


title: Critical parameters of the three-dimensional Ising spin glass

abstract:
  We report a high-precision finite-size scaling study of the critical behavior
of the three-dimensional Ising Edwards-Anderson model (the Ising spin glass).
We have thermalized lattices up to L=40 using the Janus dedicated computer. Our
analysis takes into account leading-order corrections to scaling. We obtain Tc
= 1.1019(29) for the critical temperature, \nu = 2.562(42) for the thermal
exponent, \eta = -0.3900(36) for the anomalous dimension and \omega = 1.12(10)
for the exponent of the leading corrections to scaling. Standard (hyper)scaling
relations yield \alpha = -5.69(13), \beta = 0.782(10) and \gamma = 6.13(11). We
also compute several universal quantities at Tc.


title:
Conjectures on the normal covering number of the finite symmetric and
  alternating groups

abstract:
  Let $\gamma(S_n)$ be the minimum number of proper subgroups $H_i$ of the
symmetric group $S_n$ such that each element in $S_n$ lies in some conjugate of
one of the $H_i.$ In this paper we conjecture that
$$\gamma(S_n)=\frac{n}{2}\left(1-\frac{1}{p_1}\right)
\left(1-\frac{1}{p_2}\right)+2,$$ where $p_1,p_2$ are the two smallest primes
in the factorization of $n$ and $n$ is neither a prime power nor a product of
two primes. Support for the conjecture is given by a previous result for
$n=p_1^{\alpha_1}p_2^{\alpha_2},$ with $(\alpha_1,\alpha_2)\neq (1,1)$. We give
further evidence by confirming the conjecture for integers of the form $n=15q$
for an infinite set of primes $q$, and by reporting on a Magma computation. We
make a similar conjecture for $\gamma(A_n)$, when $n$ is even, and provide a
similar amount of evidence.


title: The Exponential Formula for the Wasserstein Metric

abstract:
  A recurring obstacle in the study of Wasserstein gradient flow is the lack of
convexity of the square Wasserstein metric. In this paper, we develop a class
of transport metrics that have better convexity properties and use these
metrics to prove an Euler-Lagrange equation characterizing Wasserstein discrete
gradient flow. We then apply these results to give a new proof of the
exponential formula for the Wasserstein metric, mirroring Crandall and
Liggett's proof of the corresponding Banach space result. We conclude by using
our approach to give simple proofs of properties of the gradient flow,
including the contracting semigroup property and energy dissipation inequality.


title:
Finite element computations on quadtree meshes: strain smoothing and
  semi-analytical formulation

abstract:
  This short communication discusses two alternate techniques to treat hanging
nodes in a quadtree mesh. Both the techniques share similarities, in that, they
require only boundary information. Moreover, they do not require an explicit
form of the shape functions, unlike the conventional approaches, for example,
as in the work of Gupta \cite{gupta1978} or Tabarraei and Sukumar
\cite{tabarraeisukumar2005}. Hence, no special numerical integration technique
is required. One of the techniques relies on the strain projection procedure,
whilst the other is based on the scaled boundary finite element method.
Numerical examples are presented to demonstrate the accuracy and the
convergence properties of the two techniques.


title:
Effect of gate-driven spin resonance on the conductance of a
  one-dimensional quantum wire

abstract:
  We consider quasiballistic electron transmission in a one-dimensional quantum
wire subject to both time-independent and periodic potentials of a finger gate
that results in a coordinate- and time-dependent Rashba-type spin-orbit
coupling. A spin-dependent conductance is calculated as a function of external
constant magnetic field, the electric field frequency, and the potential
strength. The results demonstrate the effect of the gate-driven electric dipole
spin resonance in a transport phenomenon such as spin-flip electron
transmission.


title:
Variational Iteration Homotopy Perturbation Method for the Solution of
  Seventh Order Boundary Value Problems

abstract:
  The induction motor behaviour is represented by a fifth order differential
equation model. Addition of a torque correction factor to the model accurately
reproduces the transient torques and instantaneous real and reactive power
flows of the full seventh order differential equation model. The variational
iteration homotopy perturbation method (VIHPM) is employed to solve the seventh
order boundary value problems. The approximate solutions of the problems are
obtained in terms of a rapidly convergent series. Several numerical examples
are given to illustrate the implementation and efficiency of the method.


title: From Shading to Local Shape

abstract:
  We develop a framework for extracting a concise representation of the shape
information available from diffuse shading in a small image patch. This
produces a mid-level scene descriptor, comprised of local shape distributions
that are inferred separately at every image patch across multiple scales. The
framework is based on a quadratic representation of local shape that, in the
absence of noise, has guarantees on recovering accurate local shape and
lighting. And when noise is present, the inferred local shape distributions
provide useful shape information without over-committing to any particular
image explanation. These local shape distributions naturally encode the fact
that some smooth diffuse regions are more informative than others, and they
enable efficient and robust reconstruction of object-scale shape. Experimental
results show that this approach to surface reconstruction compares well against
the state-of-art on both synthetic images and captured photographs.


title: Polytropic equation of state and primordial quantum fluctuations

abstract:
  We study the primordial Universe in a cosmological model where inflation is
driven by a fluid with a polytropic equation of state $p = \alpha\rho +
k\rho^{1 + 1/n}$. We calculate the dynamics of the scalar factor and build a
Universe with constant density at the origin. We also find the equivalent
scalar field that could create such equation of state and calculate the
corresponding slow-roll parameters. We calculate the scalar perturbations, the
scalar power spectrum and the spectral index.


title: Littlest Higgs with T-parity: Status and Prospects

abstract:
  The Littlest Higgs model with T-parity is providing an attractive solution to
the fine-tuning problem. This solution is only entirely natural if its
intrinsic symmetry breaking scale f is relatively close to the electroweak
scale. We examine the constraints using the latest results from the 8 TeV run
at the LHC. Both direct searches and Higgs precision physics are taken into
account. The constraints from Higgs couplings are by now competing with
electroweak precision tests and both combined exclude f up to 694 GeV or 560
GeV depending on the implementation of the down-type Yukawa sector. Direct
searches provide robust and complementary limits and constrain f to be larger
than 638 GeV. We show that the Littlest Higgs model parameter space is slowly
driven into the TeV range. Furthermore, we develop a strategy on how to
optimise present supersymmetry searches for the considered model, with the goal
to improve the constraints and yield more stringent limits on f.


title:
Number of nodal domains and singular points of eigenfunctions of
  negatively curved surfaces with an isometric involution

abstract:
  We prove two types of nodal results for density one subsequences of an
orthonormal basis $\{\phi_j\}$ of eigenfunctions of the Laplacian on a
negatively curved compact surface. The first type of result involves the
intersections $Z_{\phi_j} \cap H$ of the nodal set $Z_{\phi_j}$ of $\phi_j$
with a smooth curve $H$. Using recent results on quantum ergodic restriction
theorems and prior results on periods of eigenfunctions over curves, we prove
that under an asymmetry assumption on $H$, the number of intersection points
tends to infinity for a density one subsequence of the $\phi_j$. . We also
prove that the number of zeros of the normal derivative $\partial_{\nu} \phi_j$
on $H$ tends to infinity. From these results we obtain a lower bound on the
number of nodal domains of even and odd eigenfunctions on surfaces with an
isometric involution. Using (and generalizing) a geometric argument of
Ghosh-Reznikov-Sarnak, we show that the number of nodal domains of even or odd
eigenfunctions tends to infinity for a density one subsequence of
eigenfunctions.


title:
A Consistent Effective Theory of Long-Wavelength Cosmological
  Perturbations

abstract:
  Effective field theory provides a perturbative framework to study the
evolution of cosmological large-scale structure. We investigate the
underpinnings of this approach, and suggest new ways to compute correlation
functions of cosmological observables. We find that, in contrast with quantum
field theory, the appropriate effective theory of classical cosmological
perturbations involves interactions that are nonlocal in time. We describe an
alternative to the usual approach of smoothing the perturbations, based on a
path-integral formulation of the renormalization group equations. This
technique allows for improved handling of short-distance modes that are
perturbatively generated by long-distance interactions.


title: Cancelation norm and the geometry of biinvariant word metrics

abstract:
  We study biinvariant word metrics on groups. We provide an efficient
algorithm for computing the biinvariant word norm on a finitely generated free
group and we construct an isometric embedding of a locally compact tree into
the biinvariant Cayley graph of a nonabelian free group. We investigate the
geometry of cyclic subgroups. We observe that in many classes of groups cyclic
subgroups are either bounded or detected by homogeneous quasimorphisms. We call
this property the bq-dichotomy and we prove it for many classes of groups of
geometric origin.


title: Large-scale Interstellar Structure and the Heliosphere

abstract:
  The properties of interstellar clouds near the Sun are ordered by the Loop I
superbubble and by the interstellar radiation field. Comparisons of the
kinematics and magnetic field of the interstellar gas flowing past the Sun,
including the Local Interstellar Cloud (LIC), indicate a geometric relation
between Loop I as defined by radio synchrotron emission, and the interstellar
magnetic field that polarizes nearby starlight. Depletion of Fe and Mg onto
dust grains in the LIC shows a surprising relation to the far ultraviolet
interstellar radiation field that is best explained by a scenario for the LIC
to be extended, possibly filamentary, porous material drifting through space
with the Loop I superbubble. The interstellar velocity and magnetic field
measured by the Interstellar Boundary Explorer (IBEX) help anchor our
understanding of the physical properties of the nearby interstellar medium.


title: Composing DTI Visualizations with End-user Programming

abstract:
  We present the design and prototype implementation of a scientific
visualization language called Zifazah for composing 3D visualizations of
diffusion tensor magnetic resonance imaging (DT-MRI or DTI) data. Unlike
existing tools allowing flexible customization of data visualizations that are
programmer-oriented, we focus on domain scientists as end users in order to
enable them to freely compose visualizations of their scientific data set. We
analyzed end-user descriptions extracted from interviews with neurologists and
physicians conducting clinical practices using DTI about how they would build
and use DTI visualizations to collect syntax and semantics for the language
design, and have discovered the elements and structure of the proposed
language. Zifazah makes use of the initial set of lexical terms and semantics
to provide a declarative language in the spirit of intuitive syntax and usage.
This work contributes three, among others, main design principles for
scientific visualization language design as well as a practice of such language
for DTI visualization with Zifazah. First, Zifazah incorporated visual symbolic
mapping based on color, size and shape, which is a sub-set of Bertin's taxonomy
migrated to scientific visualizations. Second, Zifazah is defined as a spatial
language whereby lexical representation of spatial relationship for 3D object
visualization and manipulations, which is characteristic of scientific data,
can be programmed. Third, built on top of Bertin's semiology, flexible data
encoding specifically for scientific visualizations is integrated in our
language in order to allow end users to achieve optimal visual composition at
their best. Along with sample scripts representative of our language design
features, some new DTI visualizations as the running results created by end
users using the novel visualization language have also been presented.


title: Inclusive charmed-meson production from bottom hadron decays at the LHC

abstract:
  We present predictions for the inclusive productions of the D meson
originating from bottom hadrons at the CERN LHC in the general-mass
variable-flavour-number scheme at next-to-leading order. We present results
using two methods to describe the transition for $b\rightarrow D$: a two-step
transition $b\rightarrow B \rightarrow D$, based on the $b\rightarrow B$
fragmentation functions and the spectra for $B\rightarrow D$ as measured by
CLEO and a one-step transition based on the fragmentation functions for
$b\rightarrow D$. The results of both approaches are compared.


title: Fluid juggling

abstract:
  This fluid dynamics video is an entry for the Gallery of Fluid Motion for the
66th Annual Meeting of the Fluid Dynamics Division of the American Physical
Society. We show the curious behaviour of a light ball interacting with a
liquid jet. For certain conditions, a ball can be suspended into a slightly
inclined liquid jet. We studied this phenomenon using a high speed camera. The
visualizations show that the object can be `juggled' for a variety of flow
conditions. A simple calculation showed that the ball remains at a stable
position due to a Bernoulli-like effect. The phenomenon is very stable and easy
to reproduce.


title: Partial Distance Correlation with Methods for Dissimilarities

abstract:
  Distance covariance and distance correlation are scalar coefficients that
characterize independence of random vectors in arbitrary dimension. Properties,
extensions, and applications of distance correlation have been discussed in the
recent literature, but the problem of defining the partial distance correlation
has remained an open question of considerable interest. The problem of partial
distance correlation is more complex than partial correlation partly because
the squared distance covariance is not an inner product in the usual linear
space. For the definition of partial distance correlation we introduce a new
Hilbert space where the squared distance covariance is the inner product. We
define the partial distance correlation statistics with the help of this
Hilbert space, and develop and implement a test for zero partial distance
correlation. Our intermediate results provide an unbiased estimator of squared
distance covariance, and a neat solution to the problem of distance correlation
for dissimilarities rather than distances.


title: Quantum Computing with black-box Subroutines

abstract:
  Modern programming relies on our ability to treat preprogrammed functions as
black boxes - we can invoke them as subroutines without knowing their physical
implementation. Here we show it is generally impossible to execute an unknown
quantum subroutine. This, as a special case, forbids applying black-box
subroutines conditioned on an ancillary qubit. We explore how this limits many
quantum algorithms - forcing their circuit implementation to be individually
tailored to specific inputs and inducing failure if these inputs are not known
in advance. We present a method to avoid this situation for certain
computational problems. We apply this method to enhance existing quantum
factoring algorithms; reducing their complexity, and the extent to which they
need to be tailored to factor specific numbers. Thus, we highlight a natural
property of classical information that fails in the advent of quantum logic;
and simultaneously demonstrate how to mitigate its effects in practical
situations.


title:
Polynomial Kernels for {\lambda}-extendible Properties Parameterized
  Above the Poljak-Turz\'ik Bound

abstract:
  Poljak and Turzik (Discrete Mathematics 1986) introduced the notion of
{\lambda}-extendible properties of graphs as a generalization of the property
of being bipartite. They showed that for any 0 < {\lambda} < 1 and
{\lambda}-extendible property {\Pi}, any connected graph G on n vertices and m
edges contains a spanning subgraph H in {\Pi} with at least {\lambda}m +
(1-{\lambda})(n-1)/2 edges. The property of being bipartite is
{\lambda}-extendible for {\lambda} = 1/2, and so the Poljak-Turzik bound
generalizes the well-known Edwards-Erdos bound for Max-Cut. Other examples of
{\lambda}-extendible properties include: being an acyclic oriented graph, a
balanced signed graph, or a q-colorable graph for some integer q.
  Mnich et. al. (FSTTCS 2012) defined the closely related notion of strong
{\lambda}-extendibility. They showed that the problem of finding a subgraph
satisfying a given strongly {\lambda}-extendible property {\Pi} is
fixed-parameter tractable (FPT) when parameterized above the Poljak-Turzik
bound - does there exist a spanning subgraph H of a connected graph G such that
H in {\Pi} and H has at least {\lambda}m + (1-{\lambda})(n-1)/2 + k edges? -
subject to the condition that the problem is FPT on a certain simple class of
graphs called almost-forests of cliques.
  In this paper we settle the kernelization complexity of nearly all problems
parameterized above Poljak-Turzik bounds, in the affirmative. We show that
these problems admit quadratic kernels (cubic when {\lambda} = 1/2), without
using the assumption that the problem is FPT on almost-forests of cliques. Thus
our results not only remove the technical condition of being FPT on
almost-forests of cliques from previous results, but also unify and extend
previously known kernelization results in this direction. Our results add to
the select list of generic kernelization results known in the literature.


title:
Geometric phase effects in low-energy dynamics near conical
  intersections: A study of the multidimensional linear vibronic coupling model

abstract:
  In molecular systems containing conical intersections (CIs), a nontrivial
geometric phase (GP) appears in the nuclear and electronic wave-functions in
the adiabatic representation. We study GP effects in nuclear dynamics of an
N-dimensional linear vibronic coupling (LVC) model. The main impact of GP on
low-energy nuclear dynamics is reduction of population transfer between the
local minima of the LVC lower energy surface. For the LVC model, we proposed an
isometric coordinate transformation that confines non-adiabatic effects within
a two-dimensional subsystem interacting with an N-2 dimensional environment.
Since environmental modes do not couple electronic states, all GP effects
originate from nuclear dynamics within the subsystem. We explored when the GP
affects nuclear dynamics of the isolated subsystem, and how the
subsystem-environment interaction can interfere with GP effects. Comparing
quantum dynamics with and without GP allowed us to devise simple rules to
determine significance of the GP for nuclear dynamics in this model.


title: Schur-positivity in a Square

abstract:
  Determining if a symmetric function is Schur-positive is a prevalent and, in
general, a notoriously difficult problem. In this paper we study the
Schur-positivity of a family of symmetric functions. Given a partition \lambda,
we denote by \lambda^c its complement in a square partition (m^m). We
conjecture a Schur-positivity criterion for symmetric functions of the form
s_{\mu'}s_{\mu^c}-s_{\lambda'}s_{\lambda^c}, where \lambda is a partition of
weight |\mu|-1 contained in \mu and the complement of \mu is taken in the same
square partition as the complement of \lambda. We prove the conjecture in many
cases.


title: Feedback Detection for Live Predictors

abstract:
  A predictor that is deployed in a live production system may perturb the
features it uses to make predictions. Such a feedback loop can occur, for
example, when a model that predicts a certain type of behavior ends up causing
the behavior it predicts, thus creating a self-fulfilling prophecy. In this
paper we analyze predictor feedback detection as a causal inference problem,
and introduce a local randomization scheme that can be used to detect
non-linear feedback in real-world problems. We conduct a pilot study for our
proposed methodology using a predictive system currently deployed as a part of
a search engine.


title: Homotopy theory of relative simplicial presheaves

abstract:
  We show that a category $\mathscr{M}$ equipped with a model structure defined
by a proper, locally small class of orbits $\mathscr{O}$ is Quillen equivalent
to the category of small relative presheaves
$\mathcal{P}(\mathscr{M},\mathscr{O})$.