title:
Rapid calculation of side chain packing and free energy with
  applications to protein molecular dynamics

abstract:
  To address the large gap between time scales that can be easily reached by
molecular simulations and those required to understand protein dynamics, we
propose a rapid self-consistent approximation of the side chain free energy at
every integration step. In analogy with the adiabatic Born-Oppenheimer
approximation for electronic structure, the protein backbone dynamics are
simulated as preceding according to the dictates of the free energy of an
instantaneously-equilibrated side chain potential. The side chain free energy
is computed on the fly, allowing the protein backbone dynamics to traverse a
greatly smoothed energetic landscape. This results in extremely rapid
equilibration and sampling of the Boltzmann distribution. Because our method
employs a reduced model involving single-bead side chains, we also provide a
novel, maximum-likelihood method to parameterize the side chain model using
input data from high resolution protein crystal structures. We demonstrate
state-of-the-art accuracy for predicting $\chi_1$ rotamer states while
consuming only milliseconds of CPU time. We also show that the resulting free
energies of side chains is sufficiently accurate for de novo folding of some
proteins.


title:
Cohort aggregation modelling for complex forest stands: Spruce-aspen
  mixtures in British Columbia

abstract:
  Mixed-species growth models are needed as a synthesis of ecological knowledge
and for guiding forest management. Individual-tree models have been commonly
used, but the difficulties of reliably scaling from the individual to the stand
level are often underestimated. Emergent properties and statistical issues
limit their effectiveness. A more holistic modelling of aggregates at the whole
stand level is a potentially attractive alternative. This work explores
methodology for developing biologically consistent dynamic mixture models where
the state is described by aggregate stand-level variables for species or
age/size cohorts. The methods are demonstrated and tested with a two-cohort
model for spruce-aspen mixtures named SAM. The models combine single-species
submodels and submodels for resource partitioning among the cohorts. The
partitioning allows for differences in competitive strength among species and
size classes, and for complementarity effects. Height growth reduction in
suppressed cohorts is also modelled. SAM fits well the available data, and
exhibits behaviors consistent with current ecological knowledge. The general
framework can be applied to any number of cohorts, and should be useful as a
basis for modelling other mixed-species or uneven-aged stands.


title:
GOTHIC: Gravitational oct-tree code accelerated by hierarchical time
  step controlling

abstract:
  The tree method is a widely implemented algorithm for collisionless $N$-body
simulations in astrophysics well suited for GPU(s). Adopting hierarchical time
stepping can accelerate $N$-body simulations; however, it is infrequently
implemented and its potential remains untested in GPU implementations. We have
developed a Gravitational Oct-Tree code accelerated by HIerarchical time step
Controlling named \texttt{GOTHIC}, which adopts both the tree method and the
hierarchical time step. The code adopts some adaptive optimizations by
monitoring the execution time of each function on-the-fly and minimizes the
time-to-solution by balancing the measured time of multiple functions. Results
of performance measurements with realistic particle distribution performed on
NVIDIA Tesla M2090, K20X, and GeForce GTX TITAN X, which are representative
GPUs of the Fermi, Kepler, and Maxwell generation of GPUs, show that the
hierarchical time step achieves a speedup by a factor of around 3--5 times
compared to the shared time step. The measured elapsed time per step of
\texttt{GOTHIC} is 0.30~s or 0.44~s on GTX TITAN X when the particle
distribution represents the Andromeda galaxy or the NFW sphere, respectively,
with $2^{24} =$~16,777,216 particles. The averaged performance of the code
corresponds to 10--30\% of the theoretical single precision peak performance of
the GPU.

categories: astro-ph.IM astro-ph.CO astro-ph.GA physics.comp-ph


title: Critical behavior of spherically symmetric domain wall collapse

abstract:
  Critical collapse of a spherically symmetric domain wall is investigated. The
domain wall is made of a minimally coupled scalar field with a double well
potential. We consider a sequence of the initial data which describe a
momentarily static domain wall characterized by its initial radius. The time
evolution is performed by a full general relativistic numerical code for
spherically symmetric systems. In this paper, we use the maximal slice gauge
condition, in which spacelike time slices may penetrate the black hole horizon
differently from other widely used procedures. In this paper, we consider two
specific shapes of the double well potential, and observe the Type II critical
behavior in both cases. The mass scaling, sub-critical curvature scaling, and
those fine structures are confirmed. The index of the scaling behavior agrees
with the massless scalar case.


title: Wreaths, mixed wreaths and twisted coactions

abstract:
  Distributive laws between two monads in a 2-category $\CK$, as defined by Jon
Beck in the case $\CK=\mathrm{Cat}$, were pointed out by the author to be
monads in a 2-category $\mathrm{Mnd}\CK$ of monads. Steve Lack and the author
defined wreaths to be monads in a 2-category $\mathrm{EM}\CK$ of monads with
different 2-cells from $\mathrm{Mnd}\CK$.
  Mixed distributive laws were also considered by Jon Beck, Mike Barr and,
later, various others, they are comonads in $\mathrm{Mnd}\CK$. Actually, as
pointed out by John Power and Hiroshi Watanabe, there are a number of dual
possibilities for mixed distributive laws.
  It is natural then to consider mixed wreaths as we do in this article, they
are comonads in $\mathrm{EM}\CK$. There are also mixed opwreaths: comonoids in
the Kleisli construction completion $\mathrm{Kl}\CK$ of $\CK$. The main example
studied here arises from a twisted coaction of a bimonoid on a monoid.
Corresponding to the wreath product on the mixed side is wreath convolution,
which is composition in a Kleisli-like construction. Walter Moreira's
Heisenberg product of linear endomorphisms on a Hopf algebra, is an example of
such convolution, actually involving merely a mixed distributive law.
Monoidality of the Kleisli-like construction is also discussed.


title:
Capturing the Variabilities of Distribution Network Net-Load via
  Available Flexibility of Microgrids

abstract:
  Renewable energy has attracted significant attention over the last decade,
conceivably due to its environmental benefits and the recent drops in the
development and deployment cost of the technology. The increase in renewable
generation, however, has resulted in new challenges in supply-load balancing,
owing to its intermittent, non-predictable and volatile generation features.
Several methods have been introduced to cope with negative impacts of the
renewable generation deployment. In this paper, a novel method, i.e., the
application of microgrids in capturing the variabilities of distributed
renewable generation in distribution networks is proposed and investigated.
Utilizing available flexibility of microgrids represents a local and viable
solution which leads to lower investments from electric utilities for
increasing their flexibility and providing more reserved power. It is
investigated that how the system flexibility requirements can be integrated
into the microgrid optimal scheduling model to enable microgrids in supporting
the grid operators by offering flexibility services. Using the proposed
flexibility constraints, intra-hour and inter-hour variabilities at the
distribution feeder will be efficiently captured. Numerical simulations on a
test distribution feeder, with one microgrid and several renewable-equipped
consumers, show the effectiveness of the proposed model.


title:
Global and exponential attractors of the three dimensional viscous
  primitive equations of large-scale moist atmosphere

abstract:
  This paper is concerned with the long-time behavior of solutions for the
three dimensional viscous primitive equations of large-scale moist atmosphere.
We prove the existence of a global attractor for the three dimensional viscous
primitive equations of large-scale moist atmosphere by asymptotic a priori
estimate and construct an exponential attractor by using the smoothing property
of the semigroup generated by the three dimensional viscous primitive equations
of large-scale moist atmosphere. As a byproduct, we obtain the fractal
dimension of the global attractor for the semigroup generated by the three
dimensional viscous primitive equations of large-scale moist atmosphere is
finite, which is in consistent with the results in \cite{jn2,jn1}.


title: Decentralized Transmission Policies for Energy Harvesting Devices

abstract:
  The problem of finding decentralized transmission policies in a wireless
communication network with energy harvesting constraints is formulated and
solved using the decentralized Markov decision process framework. The proposed
policy defines the transmission probabilities of all devices so as to correctly
balance the collision probabilities with the energy constraints. After an
initial coordination phase, in which the network parameters are initialized for
all devices, every node proceeds in a fully decentralized fashion. We
numerically show that, because of the harvesting, a fully orthogonal scheme
(e.g., TDMA-like) is sub-optimal in this scenario, and that the optimal
trade-off lies between an orthogonal and a completely symmetric system.


title: Mixing actions of $0$-entropy for countable amenable groups

abstract:
  It is shown that each discrete countable infinite amenable group admits a
0-entropy mixing action on a standard probability space.


title:
Water delivery from cores to disks: deuteration as a probe of the
  prestellar inheritance of H2O

abstract:
  We investigate the delivery of regular and deuterated forms of water from
prestellar cores to circumstellar disks. We adopt a semi-analytical
axisymmetric two-dimensional collapsing core model with post-processing gas-ice
astrochemical simulations, in which a layered ice structure is considered. The
physical and chemical evolutions are followed until the end of the main
accretion phase. When mass averaged over the whole disk, a forming disk has a
similar H2O abundance and HDO/H2O abundance ratio as their precollapse values
(within a factor of 2), regardless of time in our models. Consistent with
previous studies, our models suggest that interstellar water ice is delivered
to forming disks without significant alteration. On the other hand, the local
vertically averaged H2O ice abundance and HDO/H2O ice ratio can differ more, by
up to a factor of several, depending on time and distance from a central star.
Key parameters for the local variations are the fluence of stellar UV photons
en route into the disk and the ice layered structure, the latter of which is
mostly established in the prestellar stages. We also find that even if
interstellar water ice is destroyed by stellar UV and (partly) reformed prior
to disk entry, the HDO/H2O ratio in reformed water ice is similar to the
original value. This finding indicates that some caution is needed in
discussions on the prestellar inheritance of H2O based on comparisons between
the observationally derived HDO/H2O ratio in clouds/cores and that in
disks/comets. Alternatively, we propose that the ratio of D2O/HDO to HDO/H2O
better probes the prestellar inheritance of H2O. It is also found that icy
organics are more enriched in deuterium than water ice in forming disks. The
differential deuterium fractionation in water and organics is inherited from
the prestellar stages.


title:
The asset price bubbles in emerging financial markets: a new statistical
  approach

abstract:
  The bubble is a controversial and important issue. Many methods which based
on the rational expectation have been proposed to detect the bubble. However,
for some developing countries, epically China, the asset markets are so young
that for many companies, there are no dividends and fundamental value, making
it difficult (if not impossible) to measure the bubbles by existing methods.
Therefore, we proposed a simple but effective statistical method and three
statistics (that is, C, U, V) to capture and quantify asset price bubbles,
especially in immature emerging markets. To present a clear example of the
application of this method to real world problems, we also applied our method
to re-examine empirically the asset price bubble in some stock markets. Our
main contributions to current literature are as follows: firstly, this method
does not rely on fundamental value, the discount rates and dividends, therefore
is applicable to the immature markets without the sufficient data of such
kinds, secondly, this new method allows us to examine different influences
(herding behavior, abnormal fluctuation and composite influence) of bubble. Our
new statistical approach is, to the best of our knowledge, the only robust way
in existing literature to to quantify the asset price bubble especially in
emerging markets.


title: Furcation of resonance sets for one-point interactions

abstract:
  Families of one-point interactions are derived from the system consisting of
regularized two- and three-delta potentials using different paths of the
convergence of corresponding transmission matrices in the squeezing limit. This
limit is controlled by the relative rate of shrinking the width of delta-like
functions and the distance between these functions using the power
parameterization: width $l =\varepsilon^{\mu -1}$, $\mu \in [2,\, \infty]$ (for
width) and $r = \varepsilon^\tau$, $\tau \in [1,\, \infty]$ (for distance). It
is shown that at some values of real coefficients (intensities $a_1$, $a_2$ and
$a_3$) at the delta potentials, the transmission across the limit point
interactions is non-zero, whereas outside these (resonance) values the
one-point interactions are opaque splitting the system at the point of
singularity into two independent subsystems. The resonance sets of intensities
at which a non-zero transmission occurs are proved to be of four types
depending on the way of squeezing the regularized system to one point. In its
turn, on these sets the limit one-point interactions are observed to be either
single- or multiple-resonant-tunnelling potentials also depending on the
squeezing way. In the two-delta case the resonance sets are curves on the
$(a_1,a_2)$-plane and surfaces in the $(a_1,a_2,a_3)$-space for the three-delta
system. A new phenomenon of furcation of single-valued resonance sets to
multi-valued ones is observed under approaching the parameter $\mu >2$ to the
value $\mu =2$.


title: Levelized Cost of Energy Calculation for Energy Storage Systems

abstract:
  The levelized cost of energy (LCOE) presents the energy-normalized cost of a
generation asset by considering all associated costs (investment and operation)
and total generated energy over its life cycle. As LCOE is a levelized value,
it provides a quick and easy measure to compare different energy resource
technologies with different characteristics. The LCOE calculation for
large-scale power plants and distributed generations (DGs) is extensively
studied and can be found in the literature. The discussions on the LCOE
calculation for energy storage systems, however, is limited. Although still
relatively expensive compared to generation technologies, energy storage is
gaining significant attention and has been deployed extensively during the past
few years, conceivably due to its many benefits such as load shifting, energy
arbitrage, and renewable coordination. Therefore, LCOE calculation of energy
storage systems plays an important role in economic evaluation of power
systems. This paper proposes a method for calculating the LCOE of energy
storage, and further provides the sensitivity analysis with respect to changes
in capacity, electricity market prices, and efficiency.


title:
On the mechanism of gas adsorption for pristine, defective and
  functionalized graphene

abstract:
  Defect is no longer deemed an adverse aspect of graphene. Contrarily, it can
pave ways of extending applicability of graphene. Here, we discuss the effects
of three types of defects on graphene: carbon deficiency, adatom (single Fe)
dopant and introduction of functional groups (carboxyl, pyran group) on NO2 gas
adsorption via density functional theory method. We have observed that the
unsaturated carbon in defected graphene is highly active to attract NO2
molecules. Our study suggests that introducing Fe on graphene can enhance the
NO2 adsorption process. Adsorption energy calculations suggest the enhancement
in NO2 adsorption is more profound for Fe-doped mono and tetra vacant graphene
than Fe doped bi- and tri-vacant graphene. This study could potentially be
useful in developing adsorption-based applications of graphene.


title:
On the moduli space of isometric surfaces with the same mean curvature
  in 4-dimensional space forms

abstract:
  We study the moduli space of congruence classes of isometric surfaces with
the same mean curvature in 4-dimensional space forms. Having the same mean
curvature means that there exists a parallel vector bundle isometry between the
normal bundles that preserves the mean curvature vector fields. We prove that
if both Gauss lifts of a compact surface to the twistor bundle are not
vertically harmonic, then there exist at most three nontrivial congruence
classes. We show that surfaces with a vertically harmonic Gauss lift possess a
holomorphic quadratic differential, yielding thus a Hopf-type theorem. We prove
that such surfaces allow locally a one-parameter family of isometric
deformations with the same mean curvature. This family is trivial only if the
surface is superconformal. For such compact surfaces with non-parallel mean
curvature, we prove that the moduli space is the disjoint union of two sets,
each one being either finite, or a circle. In particular, for surfaces in
$\R^4$ we prove that the moduli space is a finite set, under a condition on the
Euler numbers of the tangent and normal bundles.


title:
Population growth, interest rate, and housing tax in the transitional
  China

abstract:
  This paper combines and develops the models in Lastrapes (2002) and Mankiw &
Weil (1989), which enables us to analyze the effects of interest rate and
population growth shocks on housing price in one integrated framework. Based on
this model, we carry out policy simulations to examine whether the housing
(stock or flow) tax reduces the housing price fluctuations caused by interest
rate or population growth shocks. Simulation results imply that the choice of
housing tax tools depends on the kind of shock that housing market faces. In
the situation where the housing price volatility is caused by the population
growth shock, the flow tax can reduce the volatility of housing price while the
stock tax makes no difference to it. If the shock is resulting from the
interest rate, the policy maker should not impose any kind of the housing
taxes. Furthermore, the effect of one kind of the housing tax can be
strengthened by that of the other type of housing tax.


title:
Ultrafast Emission and Detection of a Single-Electron Gaussian Wave
  Packet: A Theoretical Study

abstract:
  Generating and detecting a prescribed single-electron state is an important
step towards solid-state fermion optics. We propose how to generate an electron
in a Gaussian state, using a quantum-dot pump with gigahertz operation and
realistic parameters. With the help of a strong magnetic field, the electron
occupies a coherent state in the pump, insensitive to the details of
nonadiabatic evolution. The state changes during the emission from the pump,
governed by competition between the Landauer-Buttiker traversal time and the
passage time. When the former is much shorter than the latter, the emitted
state is a Gaussian wave packet. The Gaussian packet can be identified by using
a dynamical potential barrier, with a resolution reaching the Heisenberg
minimal uncertainty $\hbar/2$.


title:
Molecular solutions for the Maximum K-colourable Sub graph Problem in
  Adleman-Lipton model

abstract:
  Adleman showed that deoxyribonucleic acid DNA strands could be employed
towards calculating solutions to an instance of the Hamiltonian path problem .
Lipton also demonstrated that Adleman techniques could be used to solve the
Satisfiability problem. In this paper, we use Adleman Lipton model for
developing a DNA algorithm to solve Maximum k-colourable Sub graph problem. In
spite of the NP-hardness of Maximum k-colourable Sub graph problem our DNA
procedures is done in a polynomial time.


title:
Thom-Sebastiani theorems for filtered D-modules and for multiplier
  ideals

abstract:
  We give a proof of the Thom-Sebastiani type theorem for holonomic filtered
$D$-modules satisfying certain good conditions (including Hodge modules) by
using algebraic partial microlocalization. By a well-known relation between
multiplier ideals and $V$-filtrations of Kashiwara and Malgrange, the argument
in the proof implies also a Thom-Sebastiani type theorem for multiplier ideals,
which cannot be deduced from a already known proof of the Thom-Sebastiani
theorem for mixed Hodge modules (since the latter gives only the information of
graded pieces of multiplier ideals). We also sketch a more elementary proof of
the Thom-Sebastiani type theorem for multiplier ideals (as communicated to us
by M.~Musta\c{t}\v{a}), which seems to be known to specialists, although it
does not seem to be stated explicitly in the literature.


title:
Non-perturbative production rate of photons with a lattice quark
  propagator: effect of vertex correction

abstract:
  We analyze the production rate of photons from the thermal medium above the
deconfinement temperature with a quark propagator obtained from a lattice QCD
numerical simulation. The photon-quark vertex is determined gauge-invariantly,
so as to satisfy the Ward-Takahashi identity. The obtained photon production
rate shows a suppression compared to perturbative results.


title:
Channel capacity of polar coding with a given polar mismatched
  successive cancellation decoder

abstract:
  Ar{\i}kan's polar coding, is by now a well studied technique that allows
achieving the symmetric capacity of binary input memoryless channels with low
complexity encoding and decoding, provided that the polar decoding architecture
is used and the decoding metric is matched to the true channel. In this paper,
we analyze communication rates that are achievable when the polar
coding/decoding architecture is used with the decoder using an incorrect model
of the channel. We define the `polar mismatched capacity' as an analogue of the
classical mismatched capacity, give an expression for it, and derive bounds on
it.


title: The energy-population conundrum and its possible solution

abstract:
  Oil prices above $100/barrel values have proven unaffordable for the world
economy, while lower prices have proven unaffordable for unconventional oil
sources, resulting in a frantic price swing since 2007-2008. We identify and
combine for the first time the competing dynamics of oil price, economic growth
and extraction costs in a single model aiming to evaluate the near-term
consequences of these dynamics onto forthcoming oil supply. Policies able to
cope with the consequences of the resulting energy scenario are suggested in
the conclusions.


title:
Coincidences between characters to hooks and 2-part partitions on
  families arising from 2-regular classes

abstract:
  Strongly refining results by Regev, Regev and Zeilberger, we prove surprising
coincidences between characters to 2-part partitions of size n and characters
to hooks of size n+2 on two related families obtained by extending 2-regular
conjugacy classes.


title: Horndeski/Galileon black hole shadows

abstract:
  We examine observational signatures of the asymptotically de Sitter branch of
static spherically symmetric Horndeski/Galileon solutions. Our analysis
reveales that possible deviations of the photon sphere size from those of the
GR Schwarzshild solution are vanishing compared to the resolution of modern
radio-interferometric observations. These deviations are heavily suppressed by
the bounds coming from the weak-field observation. We conclude that shadow size
would not be a useful characteristic to distinguish the Horndeski/Galileon
static spherically symmetric spacetimes in the foreseeable future.


title:
Exploring the complex free energy landscape of the simplest glass by
  rheology

abstract:
  For amorphous solids, it has been intensely debated whether the traditional
view on solids, in terms of the ground state and harmonic low energy
excitations on top of it, such as phonons, is still valid. Recent theoretical
developments of amorphous solids revealed the possibility of unexpectedly
complex free energy landscapes where the simple harmonic picture breaks down.
Here we demonstrate that standard rheological techniques can be used as
powerful tools to examine non-trivial consequences of such complex free energy
landscapes. By extensive numerical simulations on a hard sphere glass under
quasi-static shear at finite temperatures, we show that, above the so-called
Gardner transition density, the elasticity breaks down, the stress relaxation
exhibits slow and aging dynamics, and the apparent shear modulus becomes
protocol-dependent. Being designed to be reproducible in laboratories, our
approach may trigger explorations of the complex free energy landscapes of a
large variety of amorphous materials.


title: Some families of operator norm inequalities

abstract:
  It is known that the function $f(e^x)/g(e^x)$ is positive definite for some
functions $f,g$ implies the operator norm inequality related to $f,g$. We treat
functions which have the following form: $f(t) = t^{(1-\sum_{i=1}^n
(a_i-b_i))/2}\prod_{i=1}^n \frac{b_i(t^{a_i}-1)}{a_i(t^{b_i}-1)}$.


title: Gopakumar-Vafa invariants via vanishing cycles

abstract:
  In this paper, we propose an ansatz for defining Gopakumar-Vafa invariants of
Calabi-Yau threefolds, using perverse sheaves of vanishing cycles. Our proposal
is a modification of a recent approach of Kiem-Li, which is itself based on
earlier ideas of Hosono-Saito-Takahashi. We conjecture that these invariants
are equivalent to other curve-counting theories such as Gromov-Witten theory
and Pandharipande-Thomas theory. Our main theorem is that, for local surfaces,
our invariants agree with PT invariants for irreducible one-cycles. We also
give a counter-example to the Kiem-Li conjectures, where our invariants match
the predicted answer. Finally, we give examples where our invariant matches the
expected answer in cases where the cycle is non-reduced, non-planar, or
non-primitive.


title: A Rate-Distortion Approach to Caching

abstract:
  This paper takes a rate-distortion approach to understanding the
information-theoretic laws governing cache-aided communications systems.
Specifically, we characterise the optimal tradeoffs between the delivery rate,
cache capacity and reconstruction distortions for a single-user problem and
some special cases of a two-user problem. Our analysis considers discrete
memoryless sources, expected- and excess-distortion constraints, and separable
and f-separable distortion functions. We also establish a strong converse for
separable-distortion functions, and we show that lossy versions of common
information (G\'{a}cs-K\"{o}rner and Wyner) play an important role in caching.
Finally, we illustrate and explicitly evaluate these laws for multivariate
Gaussian sources and binary symmetric sources.


title:
Thermal Rate Coefficients for the Astrochemical Process C + CH$^+$ $\to$
  C$_2^+$ + H by Ring Polymer Molecular Dynamics

abstract:
  Thermal rate coefficients for the astrochemical reaction C + CH$^+$ $\to$
C$_2^+$ + H were computed in the temperature range 20-300 K by using novel rate
theory based on ring polymer molecular dynamics (RPMD) on a recently published
bond-order based potential energy surface and compared with previous Langevin
capture model (LCM) and quasi-classical trajectory (QCT) calculations. Results
show that there is a significant discrepancy between the RPMD rate coefficients
and the previous theoretical results which can lead to overestimation of the
rate coefficients for the title reaction by several orders of magnitude at very
low temperatures. We argue that this can be attributed to a very challenging
energy profile along the reaction coordinate for the title reaction, not taken
into account in extenso by either the LCM or QCT approximation. In the absence
of any rigorous quantum mechanical or experimental results, the computed RPMD
rate coefficients represent state-of-the-art estimates to be included in
astrochemical databases and kinetic networks.


title:
Novel probabilistic models of spatial genetic ancestry with applications
  to stratification correction in genome-wide association studies

abstract:
  Genetic variation in human populations is influenced by geographic ancestry
due to spatial locality in historical mating and migration patterns. Spatial
population structure in genetic datasets has been traditionally analyzed using
either model-free algorithms, such as principal components analysis (PCA) and
multidimensional scaling, or using explicit spatial probabilistic models of
allele frequency evolution. We develop a general probabilistic model and an
associated inference algorithm that unify the model-based and data-driven
approaches to visualizing and inferring population structure. Our algorithm,
Geographic Ancestry Positioning (GAP), relates local genetic distances between
samples to their spatial distances, and can be used for visually discerning
population structure as well as accurately inferring the spatial origin of
individuals on a two-dimensional continuum. On both simulated and several real
datasets from diverse human populations, GAP exhibits substantially lower error
in reconstructing spatial ancestry coordinates compared to PCA.
  Our spatial inference algorithm can also be effectively applied to the
problem of population stratification in genome-wide association studies (GWAS),
where hidden population structure can create fictitious associations when
population ancestry is correlated with both the genotype and the trait. We
develop an association test that uses the ancestry coordinates inferred by GAP
to accurately account for ancestry-induced correlations in GWAS. Based on
simulations and analysis of a dataset of 10 metabolic traits measured in a
Northern Finland cohort, which is known to exhibit significant population
structure, we find that our method has superior power to current approaches.


title: Cubic edge-transitive bi-$p$-metacirculant

abstract:
  A graph is said to be a bi-Cayley graph over a group H if it admits H as a
group of automorphisms acting semiregularly on its vertices with two orbits.
For a prime p, we call a bi-Cayley graph over a metacyclic p-group a
bi-p-metacirculant. In this paper, the automorphism group of a connected cubic
edge-transitive bi-p-metacirculant is characterized for an odd prime p, and the
result reveals that a connected cubic edge-transitive bi-p-metacirculant exists
only when p=3. Using this, a classification is given of connected cubic
edge-transitive bi-Cayley graphs over an inner-abelian metacyclic 3-group. As a
result, we construct the first known infinite family of cubic semisymmetric
graphs of order twice a 3-power.


title:
Stability analysis of delay differential equations via Semidefinite
  programming

abstract:
  This paper studies the problem of stability of a parameterized delay
differential equations (DDE see equation (0.1)). After discretizing the DDE
(0.1), we show that the problem can be equivalently casted into a semi-definite
programming (SDP) see (3.2), which can be solved efficiently through some
popular algorithm, e.g., the interior point method [1].


title:
Zeros of orthogonal polynomials near an algebraic singularity of the
  measure

abstract:
  In this paper we study the local zero behavior of orthogonal polynomials
around an algebraic singularity, that is, when the measure of orthogonality is
supported on $ [-1,1] $ and behaves like $ h(x)|x - x_0|^\lambda dx $ for some
$ x_0 \in (-1,1) $, where $ h(x) $ is strictly positive and analytic. We shall
sharpen the theorem of Yoram Last and Barry Simon and show that the so-called
fine zero spacing (which is known for $ \lambda = 0$) unravels in the general
case, and the asymptotic behavior of neighbouring zeros around the singularity
can be described with the zeros of the function $ c J_{\frac{\lambda -
1}{2}}(x) + d J_{\frac{\lambda + 1}{2}}(x) $, where $ J_a(x) $ denotes the
Bessel function of the first kind and order $ a $. Moreover, using
Sturm-Liouville theory, we study the behavior of this linear combination of
Bessel functions, thus providing estimates for the zeros in question.


title: Large Scale Parallel Computations in R through Elemental

abstract:
  Even though in recent years the scale of statistical analysis problems has
increased tremendously, many statistical software tools are still limited to
single-node computations. However, statistical analyses are largely based on
dense linear algebra operations, which have been deeply studied, optimized and
parallelized in the high-performance-computing community. To make
high-performance distributed computations available for statistical analysis,
and thus enable large scale statistical computations, we introduce RElem, an
open source package that integrates the distributed dense linear algebra
library Elemental into R. While on the one hand, RElem provides direct wrappers
of Elemental's routines, on the other hand, it overloads various operators and
functions to provide an entirely native R experience for distributed
computations. We showcase how simple it is to port existing R programs to Relem
and demonstrate that Relem indeed allows to scale beyond the single-node
limitation of R with the full performance of Elemental without any overhead.


title: A white noise approach to optimal insider control of systems with delay

abstract:
  We use a white noise approach to study the problem of optimal inside control
of a stochastic delay equation driven by a Brownian motion B and a Poisson
random measure N. In particular, we use Hida-Malliavin calculus and the Donsker
delta functional to study the problem.
  We establish a sufficient and a necessary maximum principle for the optimal
control when the trader from the beginning has inside information about the
future value of some random variable related to the system.These results are
applied to the problem of optimal inside harvesting control in a population
modelled by a stochastic delay equation.
  Next, we apply a direct white noise method to find the optimal insider
portfolio in a financial market where the risky asset price is given by a
stochastic delay equation. A classical result of Pikovski and Karatzas shows
that when the inside information is B(T), where T is the terminal time of the
trading period, then the market is not viable. Our results show that with this
inside information the market is not viable even if there is delay in the
equations.


title:
An emergent geometric description for a topological phase transition in
  the Kitaev superconductor model

abstract:
  Resorting to Wilsonian renormalization group (RG) transformations, we propose
an emergent geometric description for a topological phase transition in the
Kitaev superconductor model. An effective field theory consists of an emergent
bulk action with an extra dimension, an ultraviolet (UV) boundary condition for
an initial value of a coupling function, and an infrared (IR) effective action
with a fully renormalized coupling function. The bulk action describes the
evolution of the coupling function along the direction of the extra dimension,
where the extra dimension is identified with an RG scale and the resulting
equation of motion is nothing but a $\beta-$function. In particular, the IR
effective field theory turns out to be consistent with a Callan-Symanzik
equation which takes into account both the bulk and IR boundary contributions.
This derived Callan-Symanzik equation gives rise to a metric structure. Based
on this emergent metric tensor, we uncover the equivalence of the entanglement
entropy between the emergent geometric description and the quantum field theory
in the vicinity of the quantum critical point.


title: Isoperimetric Inequalities and Magnetic Fields at CERN

abstract:
  We discuss the generalization of the classical isoperimetric inequality to
asymptotically hyperbolic Riemannian manifolds. It has been discovered that the
AdS/CFT correspondence in string theory requires that such an inequality hold
in order to be internally consistent. In a particular application, to the
systems formed in collisions of heavy ions in particle colliders, we show how
to formulate this inequality in terms of measurable physical quantities, the
magnetic field and the temperature. Experiments under way at CERN in Geneva can
thus be said to be testing an isoperimetric inequality.


title:
The one loop contributions to c(t) electric dipole moment in the CP
  violating BLMSSM

abstract:
  In the CP violating supersymmetric extension of the standard model with local
gauged baryon and lepton symmetries(BLMSSM), there are new CP violating sources
which can give new contributions to the quark electric dipole moment (EDM).
Considering the CP violating phases, we analyze the EDMs of the quarks c and t.
We take into account the contributions from the one loop diagrams.
  The numerical results are analyzed with some assumptions on the relevant
parameter space. The numerical results for the c and t EDMs can reach large
values.


title:
Discrete least-squares approximations over optimized downward closed
  polynomial spaces in arbitrary dimension

abstract:
  We analyze the accuracy of the discrete least-squares approximation of a
function $u$ in multivariate polynomial spaces $\mathbb{P}_\Lambda:={\rm span}
\{y\mapsto y^\nu \,: \, \nu\in \Lambda\}$ with $\Lambda\subset \mathbb{N}_0^d$
over the domain $\Gamma:=[-1,1]^d$, based on the sampling of this function at
points $y^1,\dots,y^m \in \Gamma$. The samples are independently drawn
according to a given probability density $\rho$ belonging to the class of
multivariate beta densities, which includes the uniform and Chebyshev densities
as particular cases. We restrict our attention to polynomial spaces associated
with \emph{downward closed} sets $\Lambda$ of \emph{prescribed} cardinality
$n$, and we optimize the choice of the space for the given sample. This
implies, in particular, that the selected polynomial space depends on the
sample. We are interested in comparing the error of this least-squares
approximation measured in $L^2(\Gamma,d\rho)$ with the best achievable
polynomial approximation error when using downward closed sets of cardinality
$n$. We establish conditions between the dimension $n$ and the size $m$ of the
sample, under which these two errors are proven to be comparable. Our main
finding is that the dimension $d$ enters only moderately in the resulting
trade-off between $m$ and $n$, in terms of a logarithmic factor $\ln(d)$, and
is even absent when the optimization is restricted to a relevant subclass of
downward closed sets, named {\it anchored} sets. In principle, this allows one
to use these methods in arbitrarily high or even infinite dimension. Our
analysis builds upon [2] which considered fixed and nonoptimized downward
closed multi-index sets. Potential applications of the proposed results are
found in the development and analysis of numerical methods for computing the
solution to high-dimensional parametric or stochastic PDEs.


title: Magnetoplasmon Fano resonance in Bose-Fermi mixtures

abstract:
  We investigate theoretically the magnetoplasmon (cyclotron) resonance in a
hybrid system consisting of spatially separated two-dimensional layers of
electron and dipolar exciton gases coupled via the Coulomb forces. We study the
dynamics of this system under the action of weak alternating external
electromagnetic field in the presence of uniform magnetic field, perpendicular
to the layers. We reveal that the electromagnetic power absorption exhibits a
double-resonance spectrum. We show that the first resonance is associated with
the conventional well-studied magnetoplasmon excitations of the electron gas
and it has a standard Lorentzian shape, whereas the second resonance is a
peculiarity attributed to the Bose-condensed exciton gas. Further, we
explicitly demonstrate that the spectrum of the system exhibits an asymmetric
Fano-type profile, where the excitonic peak is extremely narrow in comparison
with the magnetoplasmon one. We show that the shape of the resonance and the
position of the peaks depends on the magnitude of the applied magnetic field,
exciton condensate density and exciton-impurity scattering time. In particular,
the Fano profile turns into a Lorentzian shape with decreasing exciton-impurity
scattering time and the position of the plasmon-associated resonance is mainly
sensitive and determined by the magnetic field strength, whereas the
exciton-condensate peak position is determined by exciton condensate density.
It opens the experimental possibility to determine the latter quantity in
cyclotron resonance experiment.


title: The geometry of stable minimal surfaces in metric Lie groups

abstract:
  We study geometric properties of compact stable minimal surfaces with
boundary in homogeneous 3-manifolds $X$ that can be expressed as a semidirect
product of $\mathbb{R}^2$ with $\mathbb{R}$ endowed with a left invariant
metric. For any such compact minimal surface $M$, we provide a priori radius
estimate which depends only on the maximum distance of points of the boundary
$\partial M$ to a vertical geodesic of $X$. We also give a generalization of
the classical Rado's Theorem in $\mathbb{R}^3$ to the context of compact
minimal surfaces with graphical boundary over a convex horizontal domain in
$X$, and we study the geometry, existence and uniqueness of this type of
Plateau problem.


title:
Visible absorptions of potential diffuse ISM hydrocarbons: C$_9$H$_9$
  and C$_9$H$_5$ radicals

abstract:
  The laboratory detection of previously unobserved resonance-stabilized
C$_9$H$_5$ and C$_9$H$_9$ radicals in the supersonic expansion of a hydrocarbon
discharge source is reported. The radicals are tentatively assigned as
acetylenic-substituted cyclopentadienyl C$_9$H$_5$ and vinyl-substituted benzyl
C$_9$H$_9$ species. They are found to feature visible absorption bands that
coincide with a few very weak diffuse interstellar bands toward HD183143 and
HD204827.


title: Limitations on post-processing assisted quantum programming

abstract:
  A quantum multimeter is a programmable device that can implement measurements
of different observables depending on the programming quantum state inserted
into it. The advantage of this arrangement over a single purpose device is in
its versatility: one can realize various measurements simply by changing the
programming state. The classical manipulation of measurement output data is
known as post-processing. In this work we study the post-processing assisted
quantum programming, which is a protocol where quantum programming and
classical post-processing are combined. We provide examples showing that these
two processes combined can be more efficient than either of them used
separately. Furthermore, we derive an inequality relating the programming
resources to their corresponding programmed observables, thereby enabling us to
study the limitations on post-processing assisted quantum programming.


title: Limiting behavior of 3-color excitable media on arbitrary graphs

abstract:
  Fix a simple graph $G=(V,E)$ and choose a random initial 3-coloring of
vertices drawn from a uniform product measure. The 3-color cycle cellular
automaton is a process in which at each discrete time step in parallel, every
vertex with color $i$ advances to the successor color $(i+1)$ mod 3 if in
contact with a neighbor with the successor color, and otherwise retains the
same color. In the Greenberg-Hastings Model, the same update rule applies only
to color 0, while other two colors automatically advance. The limiting behavior
of these processes has been studied mainly on the integer lattices. In this
paper, we introduce a monotone comparison process defined on the universal
covering space of the underlying graph, and characterize the limiting behavior
of these processes on arbitrary connected graphs. In particular, we establish a
phase transition on the Erd\"os-R\'enyi random graph. On infinite trees, we
connect the rate of color change to the cloud speed of an associated
tree-indexed walk. We give estimates of the cloud speed by generalizing known
results to trees with leaves.


title:
Multi-photon subtracted thermal states: description, preparation and
  reconstruction

abstract:
  We present a study of optical quantum states generated by subtraction of
photons from the thermal state. Some aspects of their photon number and
quadrature distributions are discussed and checked experimentally. We
demonstrate an original method of up to ten photon subtracted state preparation
with use of just one single-photon detector. All the states where measured with
use of balanced homodyne technique, and the corresponding density matrices
where reconstructed. The fidelity between desired and reconstructed states
exceeds 99%


title: The Duffin-Schaeffer theorem in number fields

abstract:
  The Duffin-Schaeffer theorem is a well-known result from metric number
theory, which generalises Khinchin's theorem from monotonic functions to a
wider class of approximating functions.
  In recent years, there has been some interest in proving versions of
classical theorems from Diophantine approximation in various generalised
settings. In the case of number fields, there has been a version of Khinchin's
theorem proven which holds for all number fields, and a version of the
Duffin-Schaeffer theorem proven only in imaginary quadratic fields.
  In this paper, we prove a version of the Duffin-Schaeffer theorem for all
number fields.


title: Improving 1D Stellar Models with 3D Atmospheres

abstract:
  Stellar evolution codes play a major role in present-day astrophysics, yet
they share common issues. In this work we seek to remedy some of those by the
use of results from realistic and highly detailed 3D hydrodynamical simulations
of stellar atmospheres. We have implemented a new temperature stratification
extracted directly from the 3D simulations into the Garching Stellar Evolution
Code to replace the simplified atmosphere normally used. Secondly, we have
implemented the use of a variable mixing-length parameter, which changes as a
function of the stellar surface gravity and temperature -- also derived from
the 3D simulations. Furthermore, to make our models consistent, we have
calculated new opacity tables to match the atmospheric simulations. Here, we
present the modified code and initial results on stellar evolution using it.


title:
A coarse-to-fine algorithm for registration in 3D street-view
  cross-source point clouds

abstract:
  With the development of numerous 3D sensing technologies, object registration
on cross-source point cloud has aroused researchers' interests. When the point
clouds are captured from different kinds of sensors, there are large and
different kinds of variations. In this study, we address an even more
challenging case in which the differently-source point clouds are acquired from
a real street view. One is produced directly by the LiDAR system and the other
is generated by using VSFM software on image sequence captured from RGB
cameras. When it confronts to large scale point clouds, previous methods mostly
focus on point-to-point level registration, and the methods have many
limitations.The reason is that the least mean error strategy shows poor ability
in registering large variable cross-source point clouds. In this paper,
different from previous ICP-based methods, and from a statistic view, we
propose a effective coarse-to-fine algorithm to detect and register a small
scale SFM point cloud in a large scale Lidar point cloud. Seen from the
experimental results, the model can successfully run on LiDAR and SFM point
clouds, hence it can make a contribution to many applications, such as robotics
and smart city development.


title:
The matter-energy intensity distribution in a quantum gravitational
  system

abstract:
  In the framework of the method of constraint system quantization, a quantum
gravitational system (QGS) with the maximally symmetric geometry is studied.
The state vector of the QGS satisfies the set of wave equations which describes
the time evolution of a quantum system in the space of quantum fields. It is
shown that this state vector can be normalized to unity. The generalization of
the wave equations to the domain of negative values of the cosmic scale factor
is made. For the arrow of time from past to future, the state vector describes
the QGS contracting for the negative values of the scale factor and expanding
for its positive values. The intensity distributions of matter are calculated
for two exactly solvable models of spatially closed and flat QGSs formed by
dust and radiation. The analogies with the motion in time of minimum wave
packet for spatially closed QGS and with the phenomenon of diffraction in
optics for flat QGS are drawn.


title: Strain mediated tri- and quattro- interactions of adatoms

abstract:
  Lateral interactions of oxygen adatoms derived from first-principles
calculations of the O-Pd(100) system had been claimed to include trio- and
quattro terms beside pair interactions. This paper is dedicated to extend an
earlier model for substrate strain mediated interactions between adatom pairs
to include trio- and quattro terms. While monomers (sitting on high symmetric
sites) are supposed to create isotropic stress on the substrate, dimers would
create anisotropic stress. The requirement of mechanical equilibrium allows to
formulate the elastic energy as a sum of pair-, trio- and quattro terms, solved
by respective an eigenvalue problems. Resulting interactions are strongly angle
dependent and also reflect the elastic anisotropy of the substrate. A continuum
elastic model supports the long range character of the elastic interaction but
should also describe some short range features. For the elastically isotropic
tungsten substrate a closed solution for quattro interactions is presented, for
trio inter cations numerical values are given.


title:
Interference Management and Power Allocation for NOMA Visible Light
  Communications Network

abstract:
  To design an efficient interference management and multiple access scheme for
visible light communication (VLC) network, this letter leverages the
non-orthogonal multiple access (NOMA), which has received significant attention
in the $5^{th}$ generation wireless communication. With the residual
interference from the successive interference cancellation in NOMA taken into
account, we optimize the power allocation for NOMA VLC network to improve the
achievable user rate under user quality of service (QoS) constraint. The
performance of the proposed approaches is evaluated by the numerical results.


title: SSH (Sketch, Shingle, & Hash) for Indexing Massive-Scale Time Series

abstract:
  Similarity search on time series is a frequent operation in large-scale
data-driven applications. Sophisticated similarity measures are standard for
time series matching, as they are usually misaligned. Dynamic Time Warping or
DTW is the most widely used similarity measure for time series because it
combines alignment and matching at the same time. However, the alignment makes
DTW slow. To speed up the expensive similarity search with DTW, branch and
bound based pruning strategies are adopted. However, branch and bound based
pruning are only useful for very short queries (low dimensional time series),
and the bounds are quite weak for longer queries. Due to the loose bounds
branch and bound pruning strategy boils down to a brute-force search.
  To circumvent this issue, we design SSH (Sketch, Shingle, & Hashing), an
efficient and approximate hashing scheme which is much faster than the
state-of-the-art branch and bound searching technique: the UCR suite. SSH uses
a novel combination of sketching, shingling and hashing techniques to produce
(probabilistic) indexes which align (near perfectly) with DTW similarity
measure. The generated indexes are then used to create hash buckets for
sub-linear search. Our results show that SSH is very effective for longer time
sequence and prunes around 95% candidates, leading to the massive speedup in
search with DTW. Empirical results on two large-scale benchmark time series
data show that our proposed method can be around 20 times faster than the
state-of-the-art package (UCR suite) without any significant loss in accuracy.


title:
Anisotropic superconducting gaps in YNi$_2$B$_2$C: A first-principles
  investigation

abstract:
  We calculate superconducting gaps and quasiparticle density of states of
YNi$_2$B$_2$C in the framework of the density functional theory for
superconductors to investigate the origin of a highly anisotropic
superconducting gaps in this material. Calculated phonon frequencies, the
quasiparticle density of states, and the transition temperature show good
agreement with experimental results. From our calculation of superconducting
gaps and orbital character analysis, we establish that the orbital character
variation of the Fermi surface is the key factor of the anisotropic gap. Since
the electronic states that consist of mainly Ni $3 d$ orbitals couple weakly
with phonons, the superconducting gap function is suppressed for the
corresponding states, which results in the anisotropy observed in the
experiments. These results are hints to increase the transition temperature of
materials in the borocarbide family.


title: Trace distance measure of coherence for a class of qudit states

abstract:
  Recently, trace distance measure of coherence has been proposed for
characterizing the coherence of a given quantum state. However, it seems
difficult to estimate the optimal incoherent state for high dimensional states.
An explicit expression for the trace distance measure of coherence for a class
of qudit states is provided. We show that the closest incoherent state to the
class of qudit states is just the diagonal matrix obtained from it by deleting
all off-diagonal elements. It is also shown that the measure of coherence
induced by trace distance can act as a measure of coherence for this class of
qudit states with some restrictions on the strictly incoherent operations.


title:
The second mixed projection problem and the projection centroid
  conjectures

abstract:
  We provide partial answers to the open problems 4.5, 4.6 of \cite{Gardner}
and 12.9 of \cite{Lut1} regarding the classification of fixed points of the
second mixed projection operator and iterates of the projection and centroid
operators.


title:
The advanced stages of stellar evolution: impact of mass loss, rotation,
  and link with B[e] stars

abstract:
  In this paper, we discuss some consequences of rotation and mass loss on the
evolved stages of massive star evolution. The physical reasons of the time
evolution of the surface velocity are explained, and then we show how the
late-time evolution of massive stars are impacted in combination with the
effects of mass loss. The most interesting result is that in some cases, a
massive star can have a blue-red-blue evolution, opening the possibility that
Blue Supergiants are composed by two distinct populations of stars: one just
leaving the main sequence and crossing the HRD for the first time, and the
other one evolving back to the blue side of the HRD after a Red Supergiant
phase. We discuss a few possible observational tests that can allow to
distinguish these two populations, and how supergiant B[e] stars fit in this
context.


title:
A fast algorithm for a three-dimensional synthetic model of intermittent
  turbulence

abstract:
  Synthetic turbulence models are a useful tool that provide realistic
representations of turbulence, necessary to test theoretical results, to serve
as background fields in some numerical simulations, and to test analysis tools.
Models of 1D and 3D synthetic turbulence previously developed still required
large computational resources. A new wavelet-based model of synthetic
turbulence, able to produce a field with tunable spectral law, intermittency
and anisotropy, is presented here. The rapid algorithm introduced, based on the
classic $p$-model of intermittent turbulence, allows to reach a broad spectral
range using a modest computational effort. The model has been tested against
the standard diagnostics for intermittent turbulence, i.e. the spectral
analysis, the scale-dependent statistics of the field increments, and the
multifractal analysis, all showing an excellent response.


title: An Assmus-Mattson theorem for codes over commutative association schemes

abstract:
  We prove an Assmus-Mattson-type theorem for block codes where the alphabet is
the vertex set of a commutative association scheme (say, with $s$ classes).
This in particular generalizes the Assmus-Mattson-type theorems for
$\mathbb{Z}_4$-linear codes due to Tanabe (2003) and Shin, Kumar, and Helleseth
(2004), as well as the original theorem by Assmus and Mattson (1969). The
weights of a code are $s$-tuples of non-negative integers in this case, and the
conditions in our theorem for obtaining $t$-designs from the code involve
concepts from polynomial interpolation in $s$ variables. The Terwilliger
algebra is the main tool to establish our results.


title: Liftable vector fields, unfoldings and augmentations

abstract:
  We study liftable vector fields of smooth map-germs. We show how to obtain
the module of liftable vector fields of any map-germ of finite singularity type
from the module of liftable vector fields of a stable unfolding of it. As an
application, we obtain the liftable vector fields for the family $H_k$ in
Mond's list. We then show the relation between the liftable vector fields of a
stable germ and its augmentations.


title: MultiCol-SLAM - A Modular Real-Time Multi-Camera SLAM System

abstract:
  The basis for most vision based applications like robotics, self-driving cars
and potentially augmented and virtual reality is a robust, continuous
estimation of the position and orientation of a camera system w.r.t the
observed environment (scene). In recent years many vision based systems that
perform simultaneous localization and mapping (SLAM) have been presented and
released as open source. In this paper, we extend and improve upon a
state-of-the-art SLAM to make it applicable to arbitrary, rigidly coupled
multi-camera systems (MCS) using the MultiCol model. In addition, we include a
performance evaluation on accurate ground truth and compare the robustness of
the proposed method to a single camera version of the SLAM system. An open
source implementation of the proposed multi-fisheye camera SLAM system can be
found on-line https://github.com/urbste/MultiCol-SLAM.


title: A parametric reconstruction of the deceleration parameter

abstract:
  The present work is based on a parametric reconstruction of the deceleration
parameter $q(z)$ in a model for the spatially flat FRW universe filled with
dark energy and non-relativistic matter. In cosmology, the parametric
reconstruction technique deals with an attempt to build up a model by choosing
some specific evolution scenario for a cosmological parameter and then estimate
the values of the parameters with the help of different observational datasets.
In this paper, we have proposed a logarithmic parametrization of $q(z)$ to
probe the evolution history of the universe. Using the type Ia supernova
(SNIa), baryon acoustic oscillation (BAO) and the cosmic microwave background
(CMB) datasets, the constraints on the arbitrary model parameters $q_{0}$ and
$q_{1}$ are obtained (within $1\sigma$ and $2\sigma$ confidence limits) by
$\chi^{2}$-minimization technique. We have then reconstructed the deceleration
parameter, the total EoS parameter $\omega_{tot}$, the jerk parameter and have
compared the reconstructed results of $q(z)$ with other well-known
parametrizations of $q(z)$. We have also shown that two model selection
criteria (namely, Akaike information criterion and Bayesian Information
Criterion) provide the clear indication that our reconstructed model is well
consistent with other popular models.


title:
Chaotic universe model: Lotka-Volterra dynamics of the universe
  evolution

abstract:
  In this study, we consider nonlinear interactions between components such as
dark energy, dark, matter and radiation in the Friedman-Robertson-Walker
space-time framework and propose a simple interaction model based on time
evolution of the densities of these components. By using this model we show
that these interactions can be given by Lotka-Volterra equation for suitable
equation of state parameters. We numerically solve these coupling equations and
show that interaction dynamics between dark energy-dark matter-matter or dark
energy-dark matter-matter-radiation has a strange attractor for $0>w_{de}>-1$,
$w_{dm}\ge 0$, $w_{m}\ge 0$ and $w_{r}\ge 0$ values. These strange attractors
with the positive Lyapunov exponent clearly show that chaotic dynamics appears
in time evolution of the densities. These results imply that the time evolution
of the universe is chaotic in the presence of interactions between these
components. The present model may has potential to solve some cosmological
problems such as the singularity, cosmic coincidence, crunch, big rip, horizon,
oscillations, emergence of galaxies, and large scale organization of the
universe. Model also connects between dynamics of the competing species in
biological systems and dynamics of the time evolution of the universe, and
offers a new perspective and a different scenario for the universe evolution
unlike well known popular models.


title:
Optimizing egalitarian performance in the side-effects model of
  colocation for data center resource management

abstract:
  In data centers, up to dozens of tasks are colocated on a single physical
machine. Machines are used more efficiently, but tasks' performance
deteriorates, as colocated tasks compete for shared resources. As tasks are
heterogeneous, the resulting performance dependencies are complex. In our
previous work [18] we proposed a new combinatorial optimization model that uses
two parameters of a task - its size and its type - to characterize how a task
influences the performance of other tasks allocated to the same machine.
  In this paper, we study the egalitarian optimization goal: maximizing the
worst-off performance. This problem generalizes the classic makespan
minimization on multiple processors (P||Cmax). We prove that
polynomially-solvable variants of multiprocessor scheduling are NP-hard and
hard to approximate when the number of types is not constant. For a constant
number of types, we propose a PTAS, a fast approximation algorithm, and a
series of heuristics. We simulate the algorithms on instances derived from a
trace of one of Google clusters. Algorithms aware of jobs' types lead to better
performance compared with algorithms solving P||Cmax.
  The notion of type enables us to model degeneration of performance caused by
using standard combinatorial optimization methods. Types add a layer of
additional complexity. However, our results - approximation algorithms and good
average-case performance - show that types can be handled efficiently.


title:
Mechanical Properties and Failure Behavior of Phosphorene with Grain
  Boundaries

abstract:
  Using density functional tight-binding method, we studied the effect of grain
boundaries on the mechanical properties and failure behavior of phosphorene. We
found that the large angle tilt boundaries with a higher density of (5|7)
defect pairs (oriented along the AC direction) are stronger than the low-angle
tilt boundaries with a lower defect density, and similarly the large angle
boundaries with a higher density of (4|8) defect pairs (oriented along the ZZ
direction) are stronger than the low-angle boundaries with a lower defect
density. The failure is due to the rupture of the most pre-strained bonds in
the heptagons of the (5|7) defect pair or octagons of the (4|8) pairs. The
large-angle grain boundaries are better off in accommodating the pre-strained
bonds in heptagons and octagons defects, leading to a higher failure stress and
strain. The results cannot be described by Griffith-type fracture mechanics
criterion since it does not take into account the bond pre-stretching.
Interestingly, these anomalous mechanical and failure characteristics of tilt
grain boundaries in phosphorene are also shared by graphene and hexagonal
born-nitride, signifying that they may be universal for 2D materials. The
findings revealed here may be useful in tuning the mechanical properties of
phosphorene via defect engineering for specific applications.


title: Fundamental gerbes

abstract:
  For a class of affine algebraic groups $\mathcal C$ over a field, we define
the notions of $\mathcal C$-fundamental gerbe of a fibered category,
generalizing what we had done in arXiv:1204.1260 for finite group schemes. We
give sufficient conditions on $\mathcal C$ implying that a fibered category $X$
over $\kappa$ satisfying mild hypotheses admits a Nori $\mathcal C$-fundamental
gerbe. We show that these are verified in particular by the classes of
virtually abelian and virtually unipotent group schemes. In the second
situation, under a properness condition on $X$, we give a tannakian
interpretation of the resulting gerbe.


title: Classification of five-point differential-difference equations

abstract:
  Using the generalized symmetry method, we carry out, up to autonomous point
transformations, the classification of integrable equations of a subclass of
the autonomous five-point differential-difference equations. This subclass
includes such well-known examples as the Itoh-Narita-Bogoyavlensky and the
discrete Sawada-Kotera equations. The resulting list contains 17 equations some
of which seem to be new. We have found non-point transformations relating most
of the resulting equations among themselves and their generalized symmetries.


title:
Spin-Liquid--to--Spin-Liquid Transition in Kitaev Magnets Driven by
  Fractionalization

abstract:
  While phase transitions between magnetic analogs of three states of matter
--- a long-range ordered state, paramagnet, and spin liquid --- have been
extensively studied, the possibility of "liquid-liquid" transitions, namely,
between different spin liquids, remains elusive. By introducing the additional
Ising coupling into the honeycomb Kitaev model with bond asymmetry, we discover
that the Kitaev spin liquid turns into a spin-nematic quantum paramagnet before
a magnetic order is established by the Ising coupling. The quantum phase
transition between the two liquid states accompanies a topological change
driven by fractionalized excitations, the $Z_2$ gauge fluxes, and is of first
order. At finite temperatures, this yields a persisting first-order transition
line that terminates at a critical point located deep inside the regime where
quantum spins are fractionalized. It is suggested that similar transitions may
occur in other perturbed Kitaev magnets with bond asymmetry.


title:
Bacterial swarmer cells in confinement: A mesoscale hydrodynamic
  simulation study

abstract:
  A wide spectrum of Peritrichous bacteria undergo considerable physiological
changes when they are inoculated onto nutrition-rich surfaces and exhibit a
rapid and collective migration denoted as swarming. Thereby, the length of such
swarmer cells and their number of flagella increases substantially. In this
article, we investigated the properties of individual E. coli-type swarmer
cells confined between two parallel walls via mesoscale hydrodynamic
simulations, combining molecular dynamics simulations of the swarmer cell with
the multiparticle particle collision dynamics approach for the embedding fluid.
E. coli-type swarmer cells are three-times longer than their planktonic counter
parts, but their flagella density is comparable. By varying the wall
separation, we analyze the confinement effect on the flagella arrangement, on
the distribution of cells in the gap between the walls, and on the cell
dynamics. We find only a weak dependence of confinement on the bundle structure
and dynamics. The distribution of cells in the gap changes from a
geometry-dominated behavior for very narrow to fluid-dominated behavior for
wider gaps, where cells are preferentially located in the gap center for
narrower gaps and stay preferentially next to one of the walls for wider gaps.
Dynamically, the cells exhibit a wide spectrum of migration behaviors,
depending on their flagella bundle arrangement, and ranges from straight
swimming to wall rolling.


title:
More generalized groundwater model with space-time Caputo Fabrizio
  fractional differentiation

abstract:
  We prove existence and uniqueness of the flow of water within a confined
aquifer with fractional diffusion in space and fractional time derivative in
the sense of Caputo-Fabrizio. Our main method is the fixed-point theorem. We
propose the numerical approximation of the model. The Crank-Nicolson numerical
scheme was used to solve the modified model. In order to check the
effectiveness of the model, stability analysis of the numerical scheme for the
new model are presented.


title:
Self-acceleration and matter content in bicosmology from Noether
  Symmetries

abstract:
  In bigravity, when taking into account the potential existence of matter
fields minimally coupled to the second gravitation sector, the dynamics of our
Universe depends on some matter that cannot be observed in a direct way. In
this paper, we assume the existence of a Noether symmetry in bigravity
cosmologies in order to constrain the dynamics of that matter. By imposing this
assumption we obtain cosmological models with interesting phenomenology. In
fact, considering that our universe is filled with standard matter and
radiation, we show that the existence of a Noether symmetry implies that either
the dynamics of the second sector decouples, being the model equivalent to
General Relativity, or the cosmological evolution of our universe tends to a de
Sitter state with the vacuum energy in it given by the conserved quantity
associated with the symmetry. The physical consequences of the genuine
bigravity models obtained are briefly discussed. We also point out that the
first model, which is equivalent to General Relativity, may be favored due to
the potential appearance of instabilities in the second model.


title: Towards Nonperturbation Theory of Emergent Gravity

abstract:
  We investigate an emergent gravity in $(4+1)$ dimensions underlying a
geometric torsion ${\cal H}_3$ in $1.5$ order formulation. We show that an
emergent pair-symmetric $4$th order curvature tensor underlying a NS field
theory governs a torsion free geometry and is identified as the Riemann type
tensor. Interestingly a pair anti-symmetric $4$th order tensor is shown to
incorporate a dynamical correction underlying a ${\cal H}_3$ gauge potential
and is identified with a non-perturbative correction. The non-perturbative term
in the emergent action is shown to be described by a $U(1)$ gauge invariant
${\cal F}_4$ in a second order theory underlying an onshell ${\cal H}_3$ in a
first order. A complete emergent theory is elegantly described with an axion,
and hence a quintessence, coupling to the Riemann type geometries. The
curvatures are appropriately worked out to obtain a $12D$ emergent $F$ theory.
Further investigation reveals that a pair of $(M{\bar M})_{10}$-brane are
created across an event horizon. We obtain an emergent $M$ theory which in a
decoupling limit identifies with the bosonic sector of $N=1$ SUGRA in $11D$.


title: Revised Conditions for MRI due to Isorotation Theorem

abstract:
  We re-analyze the physical conditions for Magneto-rotational Instability
(MRI) within a steady axisymmetric stratified disk of plasma, in order to
account for the so-called isorotation theory (the spatial profile of
differential angular velocity depends on the magnetic flux surface). We develop
the study of linear stability around an astrophysical background configuration,
following the original derivation in \cite{Ba:1995}, but implementing the
isorotation condition as the orthogonality between the background magnetic
field and the angular velocity gradient. We demonstrate that a dependence on
the background magnetic field direction is restored in the dispersion relation
and, hence, the emergence of MRI is also influenced by field orientation.


title: Almost conformally flat hypersurfaces

abstract:
  We prove a universal lower bound for the $L^{n/2}$-norm of the Weyl tensor in
terms of the Betti numbers for compact $n$-dimensional Riemannian manifolds
that are conformally immersed as hypersurfaces in the Euclidean space. As a
consequence, we determine the homology of almost conformally flat
hypersurfaces. Furthermore, we provide a necessary condition for a compact
Riemannian manifold to admit an isometric minimal immersion as a hypersurface
in the sphere and extend a result due to Shiohama and Xu \cite{SX} for compact
hypersurfaces in any space form.


title: AdS Monopole Black Hole and Phase Transition

abstract:
  We study the Einstein-SO(3)Yang-Mills-Higgs system with a negative
cosmological constant, and find the monopole black hole solutions as well as
the trivial Reissner-Nordstr\"{o}m black hole. We discuss thermodynamical
stability of the monopole black hole in an isolated system. We expect a phase
transition between those two black holes when the mass of a black hole
increases or decreases. The type of phase transition depends on the
cosmological constant $\Lambda$ as well as the vacuum expectation value $v$ and
the coupling constant $\lambda$ of the Higgs field. Fixing $\lambda$ small, we
find there are two critical values of the cosmological constant $\Lambda_{\rm
cr (1)}(v)$ and $\Lambda_{\rm cr(2)}(v)$, which depend on $v$. If $\Lambda_{\rm
cr(1)}(v)<\Lambda (<0)$, we find the first order transition, while if
$\Lambda_{\rm cr(2)}(v)<\Lambda<\Lambda_{\rm cr(1)}(v)$, the transition becomes
second order. For the case of $\Lambda_{b}(v)<\Lambda<\Lambda_{\rm (2)}(v)$, we
again find the first order irreversible transition from the monopole black hole
to the extreme Reissner-Nordstr\"{o}m black hole. Beyond $\Lambda_{b}(v)$, no
monopole black hole exists. We also discuss thermodynamical properties of the
monopole black hole in a thermal bath system.


title:
Fibred cofinitely-coarse embeddability of box families and proper
  isometric affine actions on uniformly convex Banach spaces

abstract:
  In this paper we show that a countable, residually amenable group admits a
proper isometric affine action on some uniformly convex Banach space if and
only if one (or equivalently, all) of its box families admits a fibred
cofinitely-coarse embedding into some uniformly convex Banach space.


title: Average Values of $L$-series for Real Characters in Function Fields

abstract:
  We establish asymptotic formulae for the first and second moments of
quadratic Dirichlet $L$--functions, at the centre of the critical strip,
associated to the real quadratic function field $k(\sqrt{P})$ and inert
imaginary quadratic function field $k(\sqrt{\gamma P})$ with $P$ being a monic
irreducible polynomial over a fixed finite field $\mathbb{F}_{q}$ of odd
cardinality $q$ and $\gamma$ a generator of $\mathbb{F}_{q}^{\times}$. We also
study mean values for the class number and for the cardinality of the second
$K$-group of maximal order of the associated fields for ramified imaginary,
real, and inert imaginary quadratic function fields over $\mathbb{F}_{q}$.
  One of the main novelties of this paper is that we compute the second moment
of quadratic Dirichlet $L$-functions associated to monic irreducible
polynomials. It is worth noting that the similar second moment over number
fields is unknown.
  The second innovation of this paper comes from the fact that, if the
cardinality of the ground field is even then the task of average $L$-functions
in function fields is much harder and, in this paper, we are able to handle
this strenuous case and establish several mean values results of $L$-functions
over function fields.


title: Filter-based regularisation for impulse response modelling

abstract:
  In the last years, the success of kernel-based regularisation techniques in
solving impulse response modelling tasks has revived the interest on linear
system identification. In this work, an alternative perspective on the same
problem is introduced. Instead of relying on a Bayesian framework to include
assumptions about the system in the definition of the covariance matrix of the
parameters, here the prior knowledge is injected at the cost function level.
The key idea is to define the regularisation matrix as a filtering operation on
the parameters, which allows for a more intuitive formulation of the problem
from an engineering point of view. Moreover, this results in a unified
framework to model low-pass, band-pass and high-pass systems, and systems with
one or more resonances. The proposed filter-based approach outperforms the
existing regularisation method based on the TC and DC kernels, as illustrated
by means of Monte Carlo simulations on several linear modelling examples.


title: Same-sign W pair production in composite Higgs models

abstract:
  Non-minimal composite Higgs scenarios can contain exotic Higgs states which,
if getting observed at the Large Hadron Collider, will help to constrain the
underlying UV structure of the strong dynamics. Doubly charged Higgs bosons are
well-motivated scalar degrees of freedom in this context. Their phenomenology
in typical composite scenarios can differ from well-established Higgs triplet
extensions of the SM. Related search strategies are not necessarily adapted to
such a scenario as a consequence. In this paper we discuss the sensitivity
reach to doubly charged Higgs bosons with decays into pairs of same-sign $W$
bosons. While production cross sections are small, we show that significant
constraints on $H^{\pm\pm}\to W^{\pm}W^{\pm}$ can be obtained, providing a new
opportunity to constrain the potential composite structure of the TeV scale up
to $m_{H^{\pm\pm}}\simeq 800$~GeV.


title:
STDP allows close-to-optimal spatiotemporal spike pattern detection by
  single coincidence detector neurons

abstract:
  By recording multiple cells simultaneously, electrophysiologists have found
evidence for repeating spatiotemporal spike patterns, which can carry
information. How this information is extracted by downstream neurons is
unclear. In this theoretical paper, we investigate to what extent a single cell
could detect a given spike pattern and what the optimal parameters to do so
are, in particular the membrane time constant $\tau$. Using a leaky
integrate-and-fire (LIF) neuron with instantaneous synapses and homogeneous
Poisson input, we were able to compute this optimum analytically. Our results
indicate that a relatively small $\tau$ (at most a few tens of ms) is usually
optimal, even when the pattern is much longer. This is somewhat counter
intuitive as the resulting detector ignores most of the pattern, due to its
fast memory decay. Next, we wondered if spike-timing-dependent plasticity
(STDP) could enable a neuron to reach the theoretical optimum. We simulated a
LIF neuron equipped with additive spike-timing-dependent potentiation and
homeostatic rate-based depression, and repeatedly exposed it to a given input
spike pattern. As in previous studies, the LIF progressively became selective
to the repeating pattern with no supervision, even when the pattern was
embedded in Poisson activity. Here we show that, using certain STDP parameters,
the resulting pattern detector can be optimal. Taken together, these results
may explain how humans can learn repeating visual or auditory sequences. Long
sequences could be recognized thanks to coincidence detectors working at a much
shorter timescale. This is consistent with the fact that recognition is still
possible if a sound sequence is compressed, played backward, or scrambled using
10ms bins. Coincidence detection is a simple yet powerful mechanism, which
could be the main function of neurons in the brain.


title: Nested open books and the binding sum

abstract:
  We introduce the notion of a nested open book, a submanifold equipped with an
open book structure compatible with an ambient open book, and describe in
detail the special case of a push-off of the binding of an open book. This
enables us to explicitly describe a natural open book decomposition of a fibre
connected sum of two open books along their bindings, provided they are
diffeomorphic and admit an open book structure themselves. Furthermore, we
apply the results to contact open books, showing that the natural open book
structure of a contact fibre connected sum of two adapted open books along
their contactomorphic bindings is again adapted to the resulting contact
structure.


title: Infrared Opacities in Dense Atmospheres of Cool White Dwarf Stars

abstract:
  Dense, He-rich atmospheres of cool white dwarfs represent a challenge to the
modeling. This is because these atmospheres are constituted of a dense fluid in
which strong multi-atomic interactions determine their physics and chemistry.
Therefore, the ideal-gas-based description of absorption is no longer adequate,
which makes the opacities of these atmospheres difficult to model. This is
illustrated with severe problems in fitting the spectra of cool, He-rich stars.
Good description of the infrared (IR) opacity is essential for proper
assignment of the atmospheric parameters of these stars. Using methods of
computational quantum chemistry we simulate the IR absorption of dense He/H
media. We found a significant IR absorption from He atoms (He-He-He CIA
opacity) and a strong pressure distortion of the H$_2$-He collision-induced
absorption (CIA). We discuss the implication of these results for
interpretation of the spectra of cool stars.

categories: astro-ph.SR cond-mat.mtrl-sci physics.atom-ph physics.comp-ph physics.space-ph


title: Electrically tunable artificial gauge potential for polaritons

abstract:
  Neutral particles subject to artificial gauge potentials can behave as
charged particles in magnetic fields. This fascinating premise has led to
demonstrations of one-way waveguides, topologically protected edge states and
Landau levels for photons. In ultracold neutral atoms effective gauge fields
have allowed the emulation of matter under strong magnetic fields leading to
realization of Harper-Hofstadter and Haldane models. Here we show that
application of perpendicular electric and magnetic fields effects a tuneable
artificial gauge potential for two-dimensional microcavity exciton polaritons.
For verification, we perform interferometric measurement of the associated
phase accumulated during coherent polariton transport. Since the gauge
potential originates from the magnetoelectric Stark effect, it can be realized
for photons strongly coupled to excitations in any polarizable medium. Together
with strong polariton- polariton interactions and engineered polariton
lattices, artificial gauge fields could play a key role in investigation of
non-equilibrium dynamics of strongly correlated photons.


title: Model spaces in sub-Riemannian geometry

abstract:
  We consider sub-Riemannian spaces admitting an isometry group that is maximal
in the sense that any linear isometry between the horizontal tangent spaces is
realized by a global isometry. We will show that these spaces have a canonical
choice of partial connection on their horizontal bundle, which is determined by
isometries and generalizes the Levi-Civita connection for the special case of
Riemannian model spaces. The number of invariants needed to describe model
spaces with the same tangent cone is in general greater than one, and these
invariants are not necessarily related to the holonomy of the canonical
connections.


title: Galactic winds and the origin of large-scale magnetic fields

abstract:
  Observations of dwarf galaxies suggest the presence of large-scale magnetic
fields. However the size and slow rotation of these galaxies appear
insufficient to support a mean-field dynamo action to excite such fields. Here
we suggest a new mechanism to explain large-scale magnetic fields in galaxies
that are too small to support mean-field dynamo action. The key idea is that we
do not identify large-scale and mean magnetic fields. In our scenario the the
magnetic structures originate from a small-scale dynamo which produces
small-scale magnetic field in the galactic disc and a galactic wind that
transports this field into the galactic halo where the large turbulent
diffusion increases the scale and order of the field. As a result, the magnetic
field becomes large-scale; however its mean value remains vanishing in a strict
sense. We verify the idea by numerical modelling of two distinct simplified
configurations, a thin disc model using the no-$z$ approximation, and an
axisymmetric model using cylindrical $r,z$ coordinates. Each of these allows
reduction of the problem to two spatial dimensions. Taken together, the models
support the proposition that the general trends will persist in a fully 3D
model. We demonstrate that a pronounced large-scale pattern can develop in the
galactic halo for a wide choice of the dynamo governing parameters. We believe
that our mechanism can be relevant to explaining the presence of the fields
observed in the halos of dwarf galaxies. We emphasize that detailed modelling
of the proposed scenario needs 3D simulations, and adjustment to the specific
dynamo governing parameters of dwarf galaxies.


title: Large and moderate deviations for the left random walk on GL d (R)

abstract:
  Using martingale methods, we obtain some upper bounds for large and moderate
deviations of products of independent and identically distributed elements of
GL d (R). We investigate all the possible moment conditions, from
super-exponential moments to weak moments of order p \textgreater{} 1, to get a
complete picture of the situation. We also prove a moderate deviation principle
under an appropriate tail condition.


title:
Tunable sign change of spin Hall magnetoresistance in Pt/NiO/YIG
  structures

abstract:
  Spin Hall magnetoresistance (SMR) has been investigated in Pt/NiO/YIG
structures in a wide range of temperature and NiO thickness. The SMR shows a
negative sign below a temperature which increases with the NiO thickness. This
is contrary to a conventional SMR theory picture applied to Pt/YIG bilayer
which always predicts a positive SMR. The negative SMR is found to persist even
when NiO blocks the spin transmission between Pt and YIG, indicating it is
governed by the spin current response of NiO layer. We explain the negative SMR
by the NiO 'spin-flop' coupled with YIG, which can be overridden at higher
temperatures by positive SMR contribution from YIG. This highlights the role of
magnetic structure in antiferromagnets for transport of pure spin current in
multilayers.


title:
Learning Reporting Dynamics during Breaking News for Rumour Detection in
  Social Media

abstract:
  Breaking news leads to situations of fast-paced reporting in social media,
producing all kinds of updates related to news stories, albeit with the caveat
that some of those early updates tend to be rumours, i.e., information with an
unverified status at the time of posting. Flagging information that is
unverified can be helpful to avoid the spread of information that may turn out
to be false. Detection of rumours can also feed a rumour tracking system that
ultimately determines their veracity. In this paper we introduce a novel
approach to rumour detection that learns from the sequential dynamics of
reporting during breaking news in social media to detect rumours in new
stories. Using Twitter datasets collected during five breaking news stories, we
experiment with Conditional Random Fields as a sequential classifier that
leverages context learnt during an event for rumour detection, which we compare
with the state-of-the-art rumour detection system as well as other baselines.
In contrast to existing work, our classifier does not need to observe tweets
querying a piece of information to deem it a rumour, but instead we detect
rumours from the tweet alone by exploiting context learnt during the event. Our
classifier achieves competitive performance, beating the state-of-the-art
classifier that relies on querying tweets with improved precision and recall,
as well as outperforming our best baseline with nearly 40% improvement in terms
of F1 score. The scale and diversity of our experiments reinforces the
generalisability of our classifier.


title:
A Scanning Hall Probe Microscope for high resolution, large area,
  variable height Magnetic Field Imaging

abstract:
  We present a Scanning Hall Probe Microscope operating in ambient conditions.
One of the unique features of this microscope is the use of the same stepper
motors for both sample positioning as well as scanning, which makes it possible
to have a large scan range (few mm) in x and y directions, with a scan
resolution of 0.1 $\mu$m. Protocols have been implemented to enable scanning at
different heights from the sample surface. The z range is 35 mm.
Microstructured Hall probes of size 1-5 $\mu$m have been developed. A minimum
probe-sample distance \textless{} 2 $\mu$m has been obtained by the combination
of new Hall probes and probe-sample distance regulation using a tuning fork
based force detection technique. The system is also capable of recording local
B(z) profiles. We discuss the application of the microscope for the study of
micro-magnet arrays being developed for applications in micro-systems. *
gorky.shaw@ulg.ac.be.; Present address:


title: Introduction: Cognitive Issues in Natural Language Processing

abstract:
  This special issue is dedicated to get a better picture of the relationships
between computational linguistics and cognitive science. It specifically raises
two questions: "what is the potential contribution of computational language
modeling to cognitive science?" and conversely: "what is the influence of
cognitive science in contemporary computational linguistics?"


title:
Espaces connectifs : repr\'esentations, feuilletages, ordres,
  diff\'eologies

abstract:
  This article is a continuation of my former article "On Connectivity Spaces".
After some brief historical references relating to the subject, separation
spaces and then adjoint notions of connective representation and connective
foliation are developed. The connectivity order previously defined only in the
finite case is now generalised to all connectivity spaces, and so to connective
foliations. Finally, we start the study of some functorial relations between
connectivity and diffeological spaces, and we give a characterization of
diffeologisable connectivity spaces.


title: Black string first order flow in N=2, d=5 abelian gauged supergravity

abstract:
  We derive both BPS and non-BPS first-order flow equations for magnetically
charged black strings in five-dimensional N=2 abelian gauged supergravity,
using the Hamilton-Jacobi formalism. This is first done for the coupling to
vector multiplets only and U(1) Fayet-Iliopoulos (FI) gauging, and then
generalized to the case where also hypermultiplets are present, and abelian
symmetries of the quaternionic hyperscalar target space are gauged. We then use
these results to derive the attractor equations for near-horizon geometries of
extremal black strings, and solve them explicitely for the case where the
constants appearing in the Chern-Simons term of the supergravity action satisfy
an adjoint identity. This allows to compute in generality the central charge of
the two-dimensional conformal field theory that describes the black strings in
the infrared, in terms of the magnetic charges, the CY intersection numbers and
the FI constants. Finally, we extend the r-map to gauged supergravity and use
it to relate our flow equations to those in four dimensions.


title: Simplification of Multi-Scale Geometry using Adaptive Curvature Fields

abstract:
  We present a novel algorithm to compute multi-scale curvature fields on
triangle meshes. Our algorithm is based on finding robust mean curvatures using
the ball neighborhood, where the radius of a ball corresponds to the scale of
the features. The essential problem is to find a good radius for each ball to
obtain a reliable curvature estimation. We propose an algorithm that finds
suitable radii in an automatic way. In particular, our algorithm is applicable
to meshes produced by image-based reconstruction systems. These meshes often
contain geometric features at various scales, for example if certain regions
have been captured in greater detail. We also show how such a multi-scale
curvature field can be converted to a density field and used to guide
applications like mesh simplification.


title:
Strauss' and Lions' type results in $BV(\mathbb{R}^N)$ with an
  application to $1-$Laplacian problem

abstract:
  In this work we state and prove versions of some classical results, in the
framework of functionals defined in the space of functions of bounded variation
in $\mathbb{R}^N$. More precisely, we present versions of the Radial Lemma of
Strauss, the compactness of the embeddings of the space of radially symmetric
functions of $BV(\mathbb{R}^N)$ in some Lebesgue spaces and also a version of
the Lions Lemma, proved in his celebrated paper of 1984. As an application, we
state and prove a version of the Mountain Pass Theorem without the Palais-Smale
condition in order to get existence of a ground-state bounded variation
solution of a quasilinear elliptic problem involving the $1-$Laplacian operator
in $\mathbb{R}^N$. This seems to be the very first work dealing with stationary
problems involving this operator in the whole space.


title:
Brick by Brick Computation of the Gibbs Free Energy of Reaction in
  Solution Using Quantum Chemistry and COSMO-RS

abstract:
  The computational modelling of reactions is simple in theory but can be quite
tricky in practice. This article aims at the purpose of providing an assistance
to a proper way of describing reactions theoretically and provides rough
guidelines to the computational methods involved.
  Reactions in liquid phase chemical equilibrium can be described theoretically
in terms of the Gibbs free energy of reaction. This property can be divided
into a sum of three disjunct terms, namely the gas phase reaction energy, the
finite temperature contribution to the Gibbs free energy, and the Gibbs free
energy of solvation. The three contributions to the Gibbs free energy of
reaction can be computed separately, using different theoretico--chemical
calculation methods. While some of these terms can be obtained reliably by
computationally cheap methods, for others a high level of theory is required to
obtain predictions of quantitative quality.
  In order to propose workflows which can strike the balance between accuracy
and computational cost, a number of benchmarks assessing the precision of
different levels of theory is given.
  As an illustrative example, the low-temperature hydrogenation reaction of
acetaldehyde to ethanol in solvent toluene is shown.


title: Challenges to be addressed for realising an Ephemeral Cloud Federation

abstract:
  This paper sketches the challenges to address to realise a support able to
achieve an Ephemeral Cloud Federation, an innovative cloud computing paradigm
that enables the exploitation of a dynamic, personalised and context-aware set
of resources.
  The aim of the Ephemeral Federation is to answer to the need of combining
private data-centres with both federation of cloud providers and the resource
on the edge of the network.
  The goal of the Ephemeral Federation is to deliver a context-aware and
personalised federations of computational, data and network resources, able to
manage their heterogeneity in a highly distributed deployment, which can
dynamically bring data and computation close to the final user.


title: On three early papers by Herbert Busemann

abstract:
  This paper is a commentary and a reading guide to three papers by Herbert
Busemann, \"Uber die Geometrien, in denen die "Kreise mit unendlichem Radius"
die k\"urzesten Linien sind." (On the geometries where circles of infinite
radius are the shortest lines) (1932), "Paschsches Axiom und
Zweidimensionalit\"at," (Pasch's Axiom and Two--Dimensionality) (1933) and
"\"Uber R\"aume mit konvexen Kugeln und Parallelenaxiom (On spaces with convex
spheres and the parallel postulate) (1933). These are the first papers that
Busemann wrote on the foundations of geometry and the axiomatic
characterization of Minkowski spaces (finite-dimensional normed spaces). The
subject of these papers followed Busemann for the rest of his life, and the
three papers already contain several ideas and techniques that he developed
later on, in his work on the subject which lasted several decades. The three
papers were translated into English by Annette A'Campo. These translations,
together with the final version of present commentary, will be part of the
forthcoming edition of Busemann's Collected Papers edition.