title:
Single-trial estimation of stimulus and spike-history effects on
  time-varying ensemble spiking activity of multiple neurons: a simulation
  study

abstract:
  Neurons in cortical circuits exhibit coordinated spiking activity, and can
produce correlated synchronous spikes during behavior and cognition. We
recently developed a method for estimating the dynamics of correlated ensemble
activity by combining a model of simultaneous neuronal interactions (e.g., a
spin-glass model) with a state-space method (Shimazaki et al. 2012 PLoS Comput
Biol 8 e1002385). This method allows us to estimate stimulus-evoked dynamics of
neuronal interactions which is reproducible in repeated trials under identical
experimental conditions. However, the method may not be suitable for detecting
stimulus responses if the neuronal dynamics exhibits significant variability
across trials. In addition, the previous model does not include effects of past
spiking activity of the neurons on the current state of ensemble activity. In
this study, we develop a parametric method for simultaneously estimating the
stimulus and spike-history effects on the ensemble activity from single-trial
data even if the neurons exhibit dynamics that is largely unrelated to these
effects. For this goal, we model ensemble neuronal activity as a latent process
and include the stimulus and spike-history effects as exogenous inputs to the
latent process. We develop an expectation-maximization algorithm that
simultaneously achieves estimation of the latent process, stimulus responses,
and spike-history effects. The proposed method is useful to analyze an
interaction of internal cortical states and sensory evoked activity.


title:
Modelling Road Accident Blackspots Data with the Discrete Generalized
  Pareto distribution

abstract:
  This study shows how road traffic networks events, in particular road
accidents on blackspots, can be modelled with simple probabilistic
distributions. We considered the number of accidents and the number of deaths
on Spanish blackspots in the period 2003-2007, from Spanish General Directorate
of Traffic (DGT). We modelled those datasets, respectively, with the discrete
generalized Pareto distribution (a discrete parametric model with three
parameters) and with the discrete Lomax distribution (a discrete parametric
model with two parameters, and particular case of the previous model). For
that, we analyzed the basic properties of both parametric models: cumulative
distribution, survival, probability mass, quantile and hazard functions,
genesis and rth-order moments; applied two estimation methods of their
parameters: the $\mu$ and ($\mu+1$) frequency method and the maximum likelihood
method; and used two goodness-of-fit tests: Chi-square test and discrete
Kolmogorov-Smirnov test based on bootstrap resampling. We found that those
probabilistic models can be useful to describe the road accident blackspots
datasets analyzed.


title:
Rectifying Self Organizing Maps for Automatic Concept Learning from Web
  Images

abstract:
  We attack the problem of learning concepts automatically from noisy web image
search results. Going beyond low level attributes, such as colour and texture,
we explore weakly-labelled datasets for the learning of higher level concepts,
such as scene categories. The idea is based on discovering common
characteristics shared among subsets of images by posing a method that is able
to organise the data while eliminating irrelevant instances. We propose a novel
clustering and outlier detection method, namely Rectifying Self Organizing Maps
(RSOM). Given an image collection returned for a concept query, RSOM provides
clusters pruned from outliers. Each cluster is used to train a model
representing a different characteristics of the concept. The proposed method
outperforms the state-of-the-art studies on the task of learning low-level
concepts, and it is competitive in learning higher level concepts as well. It
is capable to work at large scale with no supervision through exploiting the
available sources.


title: Local risk-minimization under restricted information to asset prices

abstract:
  In this paper we investigate the local risk-minimization approach for a
semimartingale financial market where there are restrictions on the available
information to agents who can observe at least the asset prices. We
characterize the optimal strategy in terms of suitable decompositions of a
given contingent claim, with respect to a filtration representing the
information level, even in presence of jumps. Finally, we discuss some
practical examples in a Markovian framework and show that the computation of
the optimal strategy leads to filtering problems under the real-world
probability measure and under the minimalmartingale measure.


title: Observations of the gas cloud G2 in the Galactic Center

abstract:
  In 2011, we discovered a compact gas cloud ("G2") with roughly three Earth
masses that is falling on a near-radial orbit toward the massive black hole in
the Galactic Center. The orbit is well constrained and pericenter passage is
predicted for early 2014. Our data beautifully show that G2 gets tidally
sheared apart due to the massive black hole's force. During the next months, we
expect that in addition to the tidal effects, hydrodynamics get important, when
G2 collides with the hot ambient gas around Sgr A*. Simulations show that
ultimately, the cloud's material might fall into the massive black hole.
Predictions for the accretion rate and luminosity evolution, however, are very
difficult due to the many unknowns. Nevertheless, this might be a unique
opportunity in the next years to observe how gas feeds a massive black hole in
a galactic nucleus.


title: A remark on singular sets of vector bundle morphisms

abstract:
  If a characteristic class for two vector bundles over the same base space
does not coincide, then the bundles are not isomorphic. We give under rather
common assumptions a lower bound on the topological dimension of the set of all
points in the base over which a morphism between such bundles is not bijective.
Moreover, we show that this set is topologically non-trivial.


title: Observations of flux rope formation prior to coronal mass ejections

abstract:
  Understanding the magnetic configuration of the source regions of coronal
mass ejections (CMEs) is vital in order to determine the trigger and driver of
these events. Observations of four CME productive active regions are presented
here, which indicate that the pre-eruption magnetic configuration is that of a
magnetic flux rope. The flux ropes are formed in the solar atmosphere by the
process known as flux cancellation and are stable for several hours before the
eruption. The observations also indicate that the magnetic structure that
erupts is not the entire flux rope as initially formed, raising the question of
whether the flux rope is able to undergo a partial eruption or whether it
undergoes a transition in specific flux rope configuration shortly before the
CME.


title:
A formula for the number of spanning trees in circulant graphs with
  non-fixed generators and discrete tori

abstract:
  We consider the number of spanning trees in circulant graphs of $\beta n$
vertices with generators depending linearly on $n$. The matrix tree theorem
gives a closed formula of $\beta n$ factors, while we derive a formula of
$\beta-1$ factors. Using the same trick, we also derive a formula for the
number of spanning trees in discrete tori. Moreover, the spanning tree entropy
of circulant graphs with fixed and non-fixed generators is compared.


title:
Correlation factor for diffusion in cubic crystals with solute-vacancy
  interactions of arbitrary range

abstract:
  A formalism using a double Laplace Fourier transform of the transport
equation yields the return probabilities of the vacancy in the vicinity of the
tracer atom in the presence of solute-vacancy interactions of arbitrary
extension. Studying model cases, it is shown that taking into account the full
range of the interaction may change noticeably the correlation factor. The
latter depends tightly on the pattern of migration barriers which is chosen to
describe the vacancy jumps around the tracer atom. A thorough ab initio
evaluation of all barriers is rarely available in the literature. It is shown
that approximations often used to overcome this lack of information can be
misleading. The examination of dilute systems recently studied shows that the
interactions within the first three neighbour shells dictate the final value
with a good precision. The main improvement of the modelling comes from
dropping the restrictive assumption which impose an equal value to the jump
frequencies leading to a dissociation of the solute-vacancy pair.


title: Mixtures: sequential stability of variational entropy solutions

abstract:
  The purpose of this work is to analyze the mathematical model governing
motion of $n$-component, heat conducting reactive mixture of compressible
gases. We prove sequential stability of weak variational entropy solutions when
the state equation essentially depends on the species concentration and the
species diffusion fluxes depend on gradients of partial pressures. Of crucial
importance for our analysis is the fact that viscosity coefficients vanish on
vacuum and the source terms enjoy the admissibility condition dictated by the
second law of thermodynamics.


title: Measurement uncertainty relations

abstract:
  Measurement uncertainty relations are quantitative bounds on the errors in an
approximate joint measurement of two observables. They can be seen as a
generalization of the error/disturbance tradeoff first discussed heuristically
by Heisenberg. Here we prove such relations for the case of two canonically
conjugate observables like position and momentum, and establish a close
connection with the more familiar preparation uncertainty relations
constraining the sharpness of the distributions of the two observables in the
same state. Both sets of relations are generalized to means of order $\alpha$
rather than the usual quadratic means, and we show that the optimal constants
are the same for preparation and for measurement uncertainty. The constants are
determined numerically and compared with some bounds in the literature. In both
cases the near-saturation of the inequalities entails that the state (resp.
observable) is uniformly close to a minimizing one.


title: Quantum root-mean-square error and measurement uncertainty relations

abstract:
  Recent years have witnessed a controversy over Heisenberg's famous
error-disturbance relation. Here we resolve the conflict by way of an analysis
of the possible conceptualizations of measurement error and disturbance in
quantum mechanics. We discuss two approaches to adapting the classic notion of
root-mean-square error to quantum measurements. One is based on the concept of
noise operator; its natural operational content is that of a mean deviation of
the values of two observables measured jointly, and thus its applicability is
limited to cases where such joint measurements are available. The second error
measure quantifies the differences between two probability distributions
obtained in separate runs of measurements and is of unrestricted applicability.
We show that there are no nontrivial unconditional joint-measurement bounds for
{\em state-dependent} errors in the conceptual framework discussed here, while
Heisenberg-type measurement uncertainty relations for {\em state-independent}
errors have been proven.


title: Triggered star formation in a molecular shell created by a SNR?

abstract:
  We present a study of a new molecular shell, G126.1-0.8-14, using available
multiwavelegth Galactic plane surveys and optical Gemini observations. A well
defined shell-like structure is observed in the CO(1--0) line emission at (l,b)
= (126.1, -0.8), in the velocity range --10.5 to --15.5 km/s. The HI, emission
shows a region of low emissivity inside G126.1-0.8-14, while radio continuum
observations reveal faint non-thermal emission possibly related to this shell.
Optical spectra obtained with Gemini South show the existence of B-type stars
likely to be associated with G126.1-0.8-14. An estimate of the stellar wind
energy injected by these stars show that they alone can not be able to create
such a structure. On the other hand, one supernova explosion would provide
enough energy to generate the shell. Using the MSX, IRAS, and WISE Point Source
Catalogues we have found about 30 young stellar objects candidates, whose birth
could have been triggered by the expansion of G126.1-0.8-14. In this context,
Sh2-187 could be a consequence of the action on its surroundings of the most
massive (and thus most evolve) of the stars formed by the expanding molecular
shell.


title:
On a symbolic representation of non-central Wishart random matrices with
  applications

abstract:
  By using a symbolic method, known in the literature as the classical umbral
calculus, the trace of a non-central Wishart random matrix is represented as
the convolution of the trace of its central component and of a formal variable
involving traces of its non-centrality matrix. Thanks to this representation,
the moments of this random matrix are proved to be a Sheffer polynomial
sequence, allowing us to recover several properties. The multivariate symbolic
method generalizes the employment of Sheffer representation and a closed form
formula for computing joint moments and cumulants (also normalized) is given.
By using this closed form formula and a combinatorial device, known in the
literature as necklace, an efficient algorithm for their computations is set
up. Applications are given to the computation of permanents as well as to the
characterization of inherited estimators of cumulants, which turn useful in
dealing with minors of non-central Wishart random matrices. An asymptotic
approximation of generalized moments involving free probability is proposed.


title: Static Domain Wall in the Braneworld gravity

abstract:
  In this paper we consider a static domain wall inside a 3-brane. Differently
of the standard achievement obtained in General Relativity, the analysis
performed here gives a consistency condition for the existence of static domain
walls in a braneworld gravitational scenario. It is also shown the behavior of
the domain wall gravitational field in the newtonian limit.


title: Latter research on Euler-Mascheroni constant

abstract:
  In this work, we present a review and an example on some latter results on
the problem of approximating the Euler-Mascheroni constant. We use the method
firstly introduced in [C. Mortici, Product Approximations via Asymptotic
Integration Amer. Math. Monthly 117 (5) (2010) 434-441].


title: On the number of proper $k$-colorings in an $n$-gon

abstract:
  We define an $n$-gon to be any convex polygon with $n$ vertices. Let $V$
represent the set of vertices of the polygon. A proper $k$-coloring refers to a
function, $f$ : $V$ $\rightarrow$ $\{1, 2, 3, ... k\}$, such that for any two
vertices $u$ and $v$, if $f(u) = f(v)$, $u$ is not adjacent to $v$. The purpose
of this paper is to develop a recursive algorithm to compute the number of
proper $k$-colorings in an $n$-gon. The proposed algorithm can easily be solved
to obtain the explicit expression. This matches the explicit expression
obtained from the popular conventional solutions, which confirms the
correctness of the proposed algorithm. Often, for huge values of $n$ and $k$,
it becomes impractical to display the output numbers, which would consist of
thousands of digits. We report the answer modulo a certain number. In such
situations, the proposed algorithm is observed to run slightly faster than the
conventional recursive algorithm.


title: A note on Moufang sets

abstract:
  The notion of Moufang set was introduced by Jacques Tits in \cite{Tits92}. We
recall briefly the well-established definition and a construction which, under
certain conditions, yields a Moufang set. We show that these conditions can be
considerably relaxed, leading to a set of conditions which is easier to verify.
In the second part, we consider isomorphisms of Moufang sets and prove that
Moufang sets constructed from isomorphic groups are indeed isomorphic as
Moufang sets.


title: Network In Network

abstract:
  We propose a novel deep network structure called "Network In Network" (NIN)
to enhance model discriminability for local patches within the receptive field.
The conventional convolutional layer uses linear filters followed by a
nonlinear activation function to scan the input. Instead, we build micro neural
networks with more complex structures to abstract the data within the receptive
field. We instantiate the micro neural network with a multilayer perceptron,
which is a potent function approximator. The feature maps are obtained by
sliding the micro networks over the input in a similar manner as CNN; they are
then fed into the next layer. Deep NIN can be implemented by stacking mutiple
of the above described structure. With enhanced local modeling via the micro
network, we are able to utilize global average pooling over feature maps in the
classification layer, which is easier to interpret and less prone to
overfitting than traditional fully connected layers. We demonstrated the
state-of-the-art classification performances with NIN on CIFAR-10 and
CIFAR-100, and reasonable performances on SVHN and MNIST datasets.


title:
Generalised CP and Trimaximal TM$_1$ Lepton Mixing in $S_4$ Family
  Symmetry

abstract:
  We construct two flavor models based on $S_4$ family symmetry and generalised
CP symmetry. In both models, the $S_4$ family symmetry is broken down to the
$Z^{SU}_2$ subgroup in the neutrino sector, as a consequence, the trimaximal
$\text{TM}_1$ lepton mixing is produced. Depending on the free parameters in
the flavon potential, the Dirac CP is predicted to be either conserved or
maximally broken, and the Majorana CP phases are trivial. The two models differ
in the neutrino sector. The flavon fields are involved in the Dirac mass terms
at leading order in the first model, and the neutrino mass matrix contains
three real parameters such that the absolute neutrino masses are fixed.
Nevertheless, the flavon fields enter into the Majorana mass terms at leading
order in the second model. The leading order lepton mixing is of the
tri-bimaximal form which is broken down to $\text{TM}_1$ by the next to leading
order contributions.


title: A survey on recent extensions of the Stirling formula

abstract:
  We present a survey on recent results about Stirling's formula. More exactly,
we reffer to a method using a form of Cesaro-Stolz lemma firstly introduced in
[C. Mortici Product approximations via asymptotic integration Amer. Math.
Monthly 117 (5) (2010) 434-441]. As an example we improve a result obtained in
[C. Mortici A substantial improvement of the Stirling formula Appl. Math. Lett.
24 (2011) no. 8 1351-1354]. Finally, some numerical computations are made.


title: Mapping dark matter in the gamma-ray sky with galaxy catalogs

abstract:
  Cross-correlating gamma-ray maps with locations of galaxies in the
low-redshift Universe vastly increases sensitivity to signatures of
annihilation of dark matter particles. Low-redshift galaxies are ideal targets,
as the largest contribution to anisotropy in the gamma-ray sky from
annihilation comes from $z\lesssim 0.1$, where we expect minimal contributions
from astrophysical sources such as blazars. Cross-correlating the five-year
data of Fermi-LAT with the redshift catalog of the 2MASS survey can detect
gamma rays from annihilation if dark matter has the canonical annihilation
cross section and its mass is smaller than $\sim$100 GeV.


title: Optimal Pair of Two Linear Varieties

abstract:
  The optimal pair of two linear varieties is considered as a best
approximation problem, namely the distance between a point and the difference
set of two linear varieties. The Gram determinant allows to get the optimal
pair in closed form.


title: Learning Deep Representations By Distributed Random Samplings

abstract:
  In this paper, we propose an extremely simple deep model for the unsupervised
nonlinear dimensionality reduction -- deep distributed random samplings, which
performs like a stack of unsupervised bootstrap aggregating. First, its network
structure is novel: each layer of the network is a group of mutually
independent $k$-centers clusterings. Second, its learning method is extremely
simple: the $k$ centers of each clustering are only $k$ randomly selected
examples from the training data; for small-scale data sets, the $k$ centers are
further randomly reconstructed by a simple cyclic-shift operation. Experimental
results on nonlinear dimensionality reduction show that the proposed method can
learn abstract representations on both large-scale and small-scale problems,
and meanwhile is much faster than deep neural networks on large-scale problems.


title: Euclidean Distance between Two Linear Varieties

abstract:
  This paper addresses to the problem of finding the (minimum) Euclidean
distance between two linear varieties. This problem is, usually, solved
minimising a target function. We propose a novel approach: to use the
Moore-Penrose generalised inverse of a matrix in order to find the Euclidean
distance and, at the same time, going further by exhibiting the best
approximation pair of points.


title: Micro Black Hole Production and Evaporation

abstract:
  It has been conjectured that Micro Black Holes (MBH) may be formed in the
presence of large extra dimensions. These MBHs have very small mass and they
decay almost instantaneously. Taking into consideration quantum effects, they
should Hawking radiate mainly to Standard Model particles, this radiation then
gets modified by the non trivial geometry around the MBHs; the so called
greybody factors which filter the Hawking radiation. To test the validity of
MBH models, one needs to investigate it experimentally. A primary tool in this
investigation is simulation of the MBH formation and evaporation, including all
theoretical work that has been performed up to now. BlackMax and CHARYBDIS2 are
the most modern and realistic simulators currently available. However they
still suffer from a lack of important parameters. In this article we will
discuss the primary work that we have done to study the possible changes that
can be implemented in the simulations.


title: On Brownian Motion of Helium Ions in the Ballistic Regime

abstract:
  Discussed in the paper is the possibility of introducing the concept of
Brownian motion of various mesoparticles in the ballistic regime. The case in
point is the effect of collisions between thermal excitations in the liquid and
the test mesoparticle (allowing to trace its position) on the thermal motion of
the latter. The standard criterion for the brownian nature of the particle
motion assumes that the inequality $l_s<R_i$ is satisfied and, consequently, a
large number of collisions with the averaged response of the mesoparticle to
such a bombardment (here $l_s$ is the mean free path of helium excitations,
$R_i$ is the effective mesoparticle radius). However, the opposite limit
$l_s>R_i$, which we refer to as the ballistic regime, is also possible. It is
characterized with the specific features in the behavior of mesoparticles. The
emphasis is made on the already available evidences indicating this behavior in
the thermal motion of helium ions.


title: Time evolution of a small reactive system

abstract:
  We investigate the irreversible evolution of a small system in which a
chemical reaction takes place. We have two main goals: the first requires to
find an equation to produce a time-irreversible behavior,the second consists in
introducing a simple exactly solvable model in order to understand basic facts
in chemical kinetics. Our basic tool is the transition function counting the
number of paths joining two points in the reactive coordinates system. An exact
quantum Smoluchowski equation is derived for the reactive system in vacuum, in
the presence of a solvent in equilibrium at any time with the reactive system a
new Smoluchowski equation is obtained. The transition from a quantum regime to
a classical one is discussed. The case of a reactive system not in equilibrium
with its neighborhood is investigated in terms of path integral and via a
partial differential function. Memory effects and closure assumptions are
discussed. Using a simple potential model, the chemical rate constant is
exactly calculated and questions such as the meaning of the activation energy
or the physical content of the so-called prefactor are investigated.


title:
Technical Report: A New Multi-Device Wireless Power Transfer Scheme
  Using an Intermediate Energy Storage Circuit

abstract:
  A new multi-device wireless power transfer scheme that reduces the overall
charging time is presented. The proposed scheme employs the intermediated
energy storage (IES) circuit which consists of a constant power driving circuit
and a super-capacitor. By utilizing the characteristic of high power density of
the super-capacitor, the receiver can receive and store the energy in short
duration and supply to the battery for long time. This enables the overlap of
charging duration between all receivers. As a result, the overall charging time
can be reduced.


title:
A point in a $nd$-Polytope is the barycenter of $n$ points in its
  $d$-faces

abstract:
  Using equivariant topology, we prove that it is always possible to find $n$
points in the $d$-dimensional faces of a $nd$-dimensional convex polytope $P$
so that their center of mass is a target point in $P$. Equivalently, the
$n$-fold Minkowski sum of a $nd$-polytope's $d$-skeleton is that polytope
scaled by $n$. This verifies a conjecture by Takeshi Tokuyama.


title:
Exponent equality for capture-zone scaling in island nucleation: Theory
  and application to organic films

abstract:
  It is known in thin-film deposition that the density of nucleated clusters
$N$ varies with the deposition rate $R$ as a power law, $N \sim R^\alpha$. The
exponent $\alpha$ is a function of the critical nucleus size $i$ in a way that
changes with the aggregation-limiting process active in a given system. We
extend here to generic aggregation-limiting processes the derivation of the
analytical capture-zone distribution function $P_\beta(s) = a_\beta s^\beta
\exp(-b_\beta s^2)$ of Pimpinelli and Einstein [Phys. Rev. Lett. 99, 226102
(2007)]. We show that the exponent $\beta$ is generally related to the critical
nucleus size $i$ and to the exponent $\alpha$ by the equality $\alpha (2\beta +
d_f - 2) = 2i$ where $d_f$ is the fractal dimensionality of the clusters. This
remarkable results allows one to measure $i$ with no a priori knowledge of the
actual aggregation mechanism. We apply this equality to measuring the critical
nucleus size in pentacene deposition on mica.


title: Near-optimal labeling schemes for nearest common ancestors

abstract:
  We consider NCA labeling schemes: given a rooted tree $T$, label the nodes of
$T$ with binary strings such that, given the labels of any two nodes, one can
determine, by looking only at the labels, the label of their nearest common
ancestor.
  For trees with $n$ nodes we present upper and lower bounds establishing that
labels of size $(2\pm \epsilon)\log n$, $\epsilon<1$ are both sufficient and
necessary. (All logarithms in this paper are in base 2.)
  Alstrup, Bille, and Rauhe (SIDMA'05) showed that ancestor and NCA labeling
schemes have labels of size $\log n +\Omega(\log \log n)$. Our lower bound
increases this to $\log n + \Omega(\log n)$ for NCA labeling schemes. Since
Fraigniaud and Korman (STOC'10) established that labels in ancestor labeling
schemes have size $\log n +\Theta(\log \log n)$, our new lower bound separates
ancestor and NCA labeling schemes. Our upper bound improves the $10 \log n$
upper bound by Alstrup, Gavoille, Kaplan and Rauhe (TOCS'04), and our
theoretical result even outperforms some recent experimental studies by Fischer
(ESA'09) where variants of the same NCA labeling scheme are shown to all have
labels of size approximately $8 \log n$.


title: Small Universal Petri Nets with Inhibitor Arcs

abstract:
  We investigate the problem of construction of small-size universal Petri nets
with inhibitor arcs. We consider four descriptional complexity parameters: the
number of places, transitions, inhibitor arcs, and the maximal degree of a
transition, each of which we try to minimize.
  We give six constructions having the following values of parameters (listed
in the above order): $(30,34,13,3)$, $(14, 31, 51, 8)$, $(11, 31, 79, 11)$,
$(21,25,13,5)$, $(67, 64, 8, 3)$, $(58, 55, 8, 5)$ that improve the few known
results on this topic. Our investigation also highlights several interesting
trade-offs.


title: Adaptive Penalty-Based Distributed Stochastic Convex Optimization

abstract:
  In this work, we study the task of distributed optimization over a network of
learners in which each learner possesses a convex cost function, a set of
affine equality constraints, and a set of convex inequality constraints. We
propose a fully-distributed adaptive diffusion algorithm based on penalty
methods that allows the network to cooperatively optimize the global cost
function, which is defined as the sum of the individual costs over the network,
subject to all constraints. We show that when small constant step-sizes are
employed, the expected distance between the optimal solution vector and that
obtained at each node in the network can be made arbitrarily small. Two
distinguishing features of the proposed solution relative to other related
approaches is that the developed strategy does not require the use of
projections and is able to adapt to and track drifts in the location of the
minimizer due to changes in the constraints or in the aggregate cost itself.
The proposed strategy is also able to cope with changing network topology, is
robust to network disruptions, and does not require global information or rely
on central processors.


title:
Relation between the grafting density of liquid crystal macromolecule
  and the symmetry of self-assembled bulk phase: coarse-grained molecular
  dynamics study

abstract:
  I consider a generic coarse-grained model suitable for the study of bulk
self-assembly of liquid crystal (LC) macromolecules. The cases include LC
dendrimers, gold nanoparticles modified by polymer chains with terminating LC
groups and others. The study is focused on the relation between a number of
grafted chains, $N_{\rm ch}$, and the symmetry of the self-assembled bulk
phases. Simple space-filling arguments are used first to estimate stability
intervals for a rod-like, disc-like and spherulitic conformations in terms of
$N_{\rm ch}$. These are followed by coarse-grained molecular dynamics
simulations for both spontaneous and aided self-assembly of LC macromolecules
into bulk phases. In spontaneous self-assembly runs, essential coexistence of
rod-like and disc-like conformations is observed (via analysis of the
histograms for the molecular asphericity) in a broad interval of $N_{\rm ch}$,
which prevents the formation of defect-free structures. The use of uniaxial and
planar aiding fields is found to improve self-assembly into monodomain phases
by promoting conformations of respective symmetry. Strong shape-phase relation,
observed experimentally, is also indicated by the simulations by the
coincidence of the stability intervals for the respective conformations with
those for the bulk phases.


title:
Spatially separated polar samples of the cis and trans conformers of
  3-fluorophenol

abstract:
  We demonstrate the spatial separation of the cis- and trans-conformers of
3-fluorophenol in the gas phase based on their distinct electric dipole
moments. For both conformers we create very polar samples of their
lowest-energy rotational quantum states. A >95 % pure beam of
trans-3-fluorophenol and a >90 % pure beam of the lowest-energy rotational
states of the less polar cis-3-fluorophenol were obtained for helium and neon
supersonic expansions, respectively. This is the first demonstration of the
spatial separation of the lowest-energy rotational states of the least polar
conformer, which is necessary for strong alignment and orientation of all
individual conformers.


title:
Star Formation and Environmental Quenching of GEEC2 Group Galaxies at
  z~1

abstract:
  We present new analysis from the GEEC2 spectroscopic survey of galaxy groups
at $0.8<z<1$. Our previous work revealed an intermediate population between the
star-forming and quiescent sequences and a strong environmental dependence in
the fraction of quiescent galaxies. Only $\sim5$ per cent of star-forming
galaxies in both the group and field sample show a significant enhancement in
star formation, which suggests that quenching is the primary process in the
transition from the star-forming to the quiescent state. To model the
environmental quenching scenario, we have tested the use of different
exponential quenching timescales and delays between satellite accretion and the
onset of quenching. We find that with no delay, the quenching timescale needs
to be long in order to match the observed quiescent fraction, but then this
model produces too many intermediate galaxies. Fixing a delay time of 3 Gyr, as
suggested from the local universe, produces too few quiescent galaxies. The
observed fractions are best matched with a model that includes a delay that is
proportional to the dynamical time and a rapid quenching timescale ($\sim0.25$
Gyr), but this model also predicts intermediate galaxies H{\delta} strength
higher than that observed. Using stellar synthesis models, we have tested other
scenarios, such as the rejuvenation of star formation in early-type galaxies
and a portion of quenched galaxies possessing residual star formation. If
environment quenching plays a role in the GEEC2 sample, then our work suggests
that only a fraction of intermediate galaxies may be undergoing this transition
and that quenching occurs quite rapidly in satellite galaxies ($\lesssim0.25$
Gyr).


title:
Free energy surface reconstruction from umbrella samples using Gaussian
  process regression

abstract:
  We demonstrate how the Gaussian process regression approach can be used to
efficiently reconstruct free energy surfaces from umbrella sampling
simulations. By making a prior assumption of smoothness and taking account of
the sampling noise in a consistent fashion, we achieve a significant
improvement in accuracy over the state of the art in two or more dimensions or,
equivalently, a significant cost reduction to obtain the free energy surface
within a prescribed tolerance in both regimes of spatially sparse data and
short sampling trajectories. Stemming from its Bayesian interpretation the
method provides meaningful error bars without significant additional
computation. A software implementation is made available on www.libatoms.org.


title:
Free energy surface reconstruction from umbrella samples using Gaussian
  process regression II: Multiple collective variables

abstract:
  We demonstrate how a prior assumption of smoothness can be used to enhance
the reconstruction of free energy profiles from multiple umbrella sampling
simulations using the Bayesian Gaussian process regression approach. The method
we derive allows the concurrent use of histograms and free energy gradients and
can easily be extended to include further data. In Part I we review the
necessary theory and test the method for one collective variable. We
demonstrate improved performance with respect to the weighted histogram
analysis method and obtain meaningful error bars without any significant
additional computation. In Part II we consider the case of multiple collective
variables and compare to a reconstruction using least squares fitting of radial
basis functions. We find substantial improvements in the regimes of spatially
sparse data or short sampling trajectories. A software implementation is made
available on www.libatoms.org.


title:
On the Classification of Elliptic Fibrations modulo Isomorphism on K3
  Surfaces with large Picard Number

abstract:
  Motivated by a problem originating in string theory, we study elliptic
fibrations on K3 surfaces with large Picard number modulo isomorphism. We give
methods to determine upper bounds for the number of inequivalent K3 surfaces
sharing the same frame lattice. For any given Neron--Severi lattice $S_X$, such
a bound on the `multiplicity' can be derived by investigating the quotient of
the isometry group of $S_X$ by the automorphism group. The resulting bounds are
strongest for large Picard numbers and multiplicities of unity do indeed occur
for a number of K3 surfaces with Picard number 20. Under a few extra
conditions, a more refined analysis is also possible by explicitly studying the
embedding of $S_X$ into the even unimodular lattice ${\rm II}_{1,25}$ and
exploiting the detailed structure of the isometry groups of $S_X$ and ${\rm
II}_{1,25}$. We illustrate these methods in examples and derive bounds for the
number of elliptic fibrations on Kummer surfaces of Picard numbers 17 and 20.
As an intermediate step, we also discuss coarser classification schemes and
review known results.


title:
Which Memristor Theory is Best for Relating Devices Properties to
  Memristive Function?

abstract:
  There are three theoretical models which purport to relate
experimentally-measurable or fabrication-controllable device properties to the
memristor's operation: 1. Strukov et al's phenomenological model; 2. Georgiou
et al's Bernoulli rewrite of that phenomenological model; 3. Gale's
memory-conservation model. They differ in their prediction of the effect on
memristance of changing the electrode size and factors that affect the
hysteresis. Using a batch of TiO$_2$ sol-gel memristors fabricated with
different top electrode widths we test and compare these three theories. It was
found that, contrary to model 2's prediction, the `dimensionless lumped
parameter', $\beta$, did not correlate to any measure of the hysteresis.
Contrary to model 1, memristance was found to be dependent on the three spatial
dimensions of the TiO$_2$ layer, as was predicted by model 3. Model 3 was found
to fit the change in resistance value with electrode size. Simulations using
model 3 and experimentally derived values for contact resistance gave
hysteresis values that were linearly related to (and only one order of
magnitude out) from the experimentally-measured values. Memristor hysteresis
was found to be related to the ON state resistance and thus the electrode size
(as those two are related). These results offer a verification of the
memory-conservation theory of memristance and its association of the vacancy
magnetic flux with the missing magnetic flux in memristor theory. This is the
first paper to experimentally test various theories pertaining to the operation
of memristor devices.

categories: cond-mat.mtrl-sci cond-mat.mes-hall cs.ET physics.chem-ph


title:
Achievable Diversity-Rate Tradeoff of MIMO AF Relaying Systems with MMSE
  Transceivers

abstract:
  This paper investigates the diversity order of the minimum mean squared error
(MMSE) based optimal transceivers in multiple-input multiple-output (MIMO)
amplify-and-forward (AF) relaying systems. While the diversity-multiplexing
tradeoff (DMT) analysis accurately predicts the behavior of the MMSE receiver
for the positive multiplexing gain, it turned out that the performance is very
unpredictable via DMT for the case of fixed rates, because MMSE strategies
exhibit a complicated rate dependent behavior. In this paper, we establish the
diversity-rate tradeoff performance of MIMO AF relaying systems with the MMSE
transceivers as a closed-form for all fixed rates, thereby providing a complete
characterization of the diversity order together with the earlier work on DMT.


title:
Convergence of the Point Integral method for the Poisson equation with
  Dirichlet boundary on point cloud

abstract:
  The Poisson equation on manifolds plays an fundamental role in many
applications. Recently, we proposed a novel numerical method called the Point
Integral method (PIM) to solve the Poisson equations on manifolds from point
clouds. In this paper, we prove the convergence of the point integral method
for solving the Poisson equation with the Dirichlet boundary condition.


title: An Ontology-based Model for Indexing and Retrieval

abstract:
  Starting from an unsolved problem of information retrieval this paper
presents an ontology-based model for indexing and retrieval. The model combines
the methods and experiences of cognitive-to-interpret indexing languages with
the strengths and possibilities of formal knowledge representation. The core
component of the model uses inferences along the paths of typed relations
between the entities of a knowledge representation for enabling the
determination of hit quantities in the context of retrieval processes. The
entities are arranged in aspect-oriented facets to ensure a consistent
hierarchical structure. The possible consequences for indexing and retrieval
are discussed.


title:
Optimization for Compressed Sensing: the Simplex Method and Kronecker
  Sparsification

abstract:
  In this paper we present two new approaches to efficiently solve large-scale
compressed sensing problems. These two ideas are independent of each other and
can therefore be used either separately or together. We consider all
possibilities.
  For the first approach, we note that the zero vector can be taken as the
initial basic (infeasible) solution for the linear programming problem and
therefore, if the true signal is very sparse, some variants of the simplex
method can be expected to take only a small number of pivots to arrive at a
solution. We implemented one such variant and demonstrate a dramatic
improvement in computation time on very sparse signals.
  The second approach requires a redesigned sensing mechanism in which the
vector signal is stacked into a matrix. This allows us to exploit the Kronecker
compressed sensing (KCS) mechanism. We show that the Kronecker sensing requires
stronger conditions for perfect recovery compared to the original vector
problem. However, the Kronecker sensing, modeled correctly, is a much sparser
linear optimization problem. Hence, algorithms that benefit from sparse problem
representation, such as interior-point methods, can solve the Kronecker sensing
problems much faster than the corresponding vector problem. In our numerical
studies, we demonstrate a ten-fold improvement in the computation time.


title: Off-equilibrium surface tension in colloidal suspensions

abstract:
  We study the fingering instability of the interface between two miscible
fluids, a colloidal suspension and its own solvent. The temporal evolution of
the interface in a Hele-Shaw cell is found to be governed by the competition
between the non-linear viscosity of the suspension and an off-equilibrium,
effective surface tension $\Gamma_e$. By studying suspensions in a wide range
of volume fractions, $\Phi_\mathrm{C}$, we show that $\Gamma_e \sim
\Phi_\mathrm{C}^2$, in agreement with Korteweg's theory for miscible fluids.
The surface tension exhibits an anomalous increase with particle size, which we
account for using entropy arguments.


title: On Constraint Satisfaction Problems below P

abstract:
  Symmetric Datalog, a fragment of the logic programming language Datalog, is
conjectured to capture all constraint satisfaction problems (CSP) in L.
Therefore developing tools that help us understand whether or not a CSP can be
defined in symmetric Datalog is an important task. It is widely known that a
CSP is definable in Datalog and linear Datalog if and only if that CSP has
bounded treewidth and bounded pathwidth duality, respectively. In the case of
symmetric Datalog, Bulatov, Krokhin and Larose ask for such a duality (2008).
We provide two such dualities, and give applications. In particular, we give a
short and simple new proof of the result of Dalmau and Larose that "Maltsev +
Datalog -> symmetric Datalog" (2008).
  In the second part of the paper, we provide some evidence for the conjecture
of Dalmau (2002) that every CSP in NL is definable in linear Datalog. Our
results also show that a wide class of CSPs-CSPs which do not have bounded
pathwidth duality (e.g., the P-complete Horn-3Sat problem)-cannot be defined by
any polynomial size family of monotone read-once nondeterministic branching
programs.


title: The Flip Diameter of Rectangulations and Convex Subdivisions

abstract:
  We study the configuration space of rectangulations and convex subdivisions
of $n$ points in the plane. It is shown that a sequence of $O(n\log n)$
elementary flip and rotate operations can transform any rectangulation to any
other rectangulation on the same set of $n$ points. This bound is the best
possible for some point sets, while $\Theta(n)$ operations are sufficient and
necessary for others. Some of our bounds generalize to convex subdivisions of
$n$ points in the plane.


title:
Biases on cosmological parameter estimators from galaxy cluster number
  counts

abstract:
  Sunyaev-Zel'dovich (SZ) surveys are promising probes of cosmology - in
particular for Dark Energy (DE) -, given their ability to find distant clusters
and provide estimates for their mass. However, current SZ catalogs contain tens
to hundreds of objects and maximum likelihood estimators may present biases for
such sample sizes. In this work we use the Monte Carlo approach to determine
the presence of bias on cosmological parameter estimators from cluster
abundance as a function of the area and depth of the survey, and the number of
cosmological parameters fitted. Assuming perfect knowledge of mass and redshift
some estimators have non-negligible biases. For example, the bias of $\sigma_8$
corresponds to about $40%$ of its statistical error bar when fitted together
with $\Omega_c$ and $w_0$. Including a SZ mass-observable relation decreases
the relevance of the bias, for the typical sizes of current surveys. The biases
become negligible when combining the SZ data with other cosmological probes.
However, we show that the biases from SZ estimators do not go away with
increasing sample sizes and they may become the dominant source of error for an
all sky survey at the South Pole Telescope (SPT) sensitivity. The results of
this work validate the use of the current maximum likelihood methods for
present SZ surveys, but highlight the need for further studies for upcoming
experiments. [abridged]


title: Maximally strong entropic uncertainty relations and gauge invariance

abstract:
  Uncertainty relations are among the unique fingerprints of quantum physics,
being direct expression of non-commutativity and complementarity. Entropic
uncertainty relations arise in quantum information theory as the most natural
expression of the uncertainty principle and have proven themselves important
tools for cryptographic security proofs. An open question has been how strong
entropic uncertainty relations can be. Here we answer this question by showing
that there exist observables that obey maximally strong entropic uncertainty
relations in high dimensional Hilbert spaces. Actually, we show that maximally
strong uncertainty relations are typically verified if the observables are
distributed somehow uniformly. In particular, we show that phase randomness in
a mutually unbiased basis is sufficient, providing a link between uncertainty
relations and local gauge invariance. For quantum systems of finite dimensions
our approach provides an explicit relation between the strength of the
uncertainty and its probability.


title: Non-equilibrium conductivity at quantum critical points

abstract:
  Quantum criticality provides an important route to revealing universal
non-equilibrium behaviour. A canonical example of a quantum critical point is
the Bose-Hubbard model, which we study under the application of an electric
field. A Boltzmann transport formalism and $\epsilon$-expansion are used to
obtain the non-equilibrium conductivity and current noise. This approach allows
us to explicitly identify how a universal non-equilibrium steady state is
maintained, by identifying the rate-limiting step in balancing Joule heating
and dissipation to a heat bath. It also reveals that the non-equilibrium
distribution function is very far from a thermal distribution.


title:
Lessons from Comparisons between the Nuclear Region of the Milky Way &
  Those in Nearby Spirals

abstract:
  The Milky Way appears is a typical barred spiral, and comparisons can be made
between its nuclear region and those of structurally similar nearby spirals.
Maffei 2, M83, IC 342 and NGC 253 are nearby systems whose nuclear region
properties contrast with those of the Milky Way. Stellar masses derived from
NIR photometery, molecular gas masses and star formation rates allow us to
assess the evolutionary states of this set of nuclear regions. These data
suggest similarities between nuclear regions in terms of their stellar content
while highlighting significant differences in current star formation rates. In
particular current star formation rates appear to cover a larger range than
expected based on the molecular gas masses. This behavior is consistent with
nuclear region star formation experiencing episodic variations. Under this
hypothesis the Milky Way's nuclear region currently may be in a low star
formation rate phase.


title:
Electrical conductivity of the quark-gluon plasma and soft photon
  spectrum in heavy-ion collisions

abstract:
  We extract the electrical conductivity $\sigma_0$ of the quark gluon
plasma(QGP) and study the effects of magnetic field and chiral anomaly on soft
photon azimuthal anisotropy, $v_2$, based on the thermal photon spectrum at
$0.4GeV<p_{\perp}<0.6GeV$ at RHIC energy. As a basis for our analysis, we
derive the behavior of retarded photon self energy of a strongly interacting
neutral plasma in hydrodynamic regime in the presence of magnetic field and
chiral anomaly. By evolving the resulting soft thermal photon production rate
over the realistic hydrodynamic background and comparing the results with the
preliminary data from the PHENIX Collaboration, we found that the electrical
conductivity at QGP temperature is in the range: $0.4<\sigma_0/(e^{2}T) <1.1$,
which is comparable with recent studies on lattice. We also compare the
contribution from the magnetic field and chiral anomaly to soft thermal photon
$v_{2}$ with the data. We argue that at LHC, the chiral magnetic wave would
give negative contribution to photon $v_2$.


title:
Breakout and Tether-cutting Eruption Models Are Both Catastrophic
  (Sometimes)

abstract:
  We present a simplified analytic model of a quadrupolar magnetic field and
flux rope to model coronal mass ejections. The model magnetic field is
two-dimensional, force-free and has current only on the axis of the flux rope
and within two currents sheets. It is a generalization of previous models
containing a single current sheet anchored to a bipolar flux distribution. Our
new model can undergo quasi-static evolution due either to changes at the
boundary or to magnetic reconnection at either current sheet. We find that all
three kinds of evolution can lead to a catastrophe known as loss of
equilibrium. Some equilibria can be driven to catastrophic instability either
through reconnection at the lower current sheet, known as tether cutting, or
through reconnection at the upper current sheet, known as breakout. Other
equilibria can be destabilized through only one and not the other. Still others
undergo no instability, but evolve increasingly rapidly in response to slow
steady driving (ideal or reconnective). One key feature of every case is a
response to reconnection different from that found in simpler systems. In our
two-current sheet model a reconnection electric field in one current sheet
causes the current in that sheet to {\em increase} rather than decrease. This
suggests the possibility for the microscopic reconnection mechanism to run
away.


title: Measure synchronization in quantum many-body systems

abstract:
  The concept of measure synchronization between two coupled quantum many-body
systems is presented. In general terms we consider two quantum many-body
systems whose dynamics gets coupled through the contact particle-particle
interaction. This coupling is shown to produce measure synchronization, a
generalization of synchrony to a large class of systems which takes place in
absence of dissipation. We find that in quantum measure synchronization, the
many-body quantum properties for the two subsystems, e.g. condensed fractions
and particle fluctuations, behave in a coordinated way. To illustrate the
concept we consider a simple case of two species of bosons occupying two
distinct quantum states. Measure synchronization can be readily explored with
state-of-the-art techniques in ultracold atomic gases and, if propertly
controlled, be employed to share quantum correlations between different degrees
of freedom.

categories: cond-mat.quant-gas nlin.CD nlin.PS quant-ph


title:
Rippled area formed by surface plasmon polaritons upon femtosecond laser
  double-pulse irradiation of silicon: the role of carrier generation and
  relaxation processes

abstract:
  The formation of laser-induced periodic surface structures (LIPSS, ripples)
upon irradiation of silicon with multiple irradiation sequences consisting of
femtosecond laser pulse pairs (pulse duration 150 fs, central wavelength 800
nm) is studied numerically using a rate equation system along with a
two-temperature model accounting for one- and two-photon absorption and
subsequent carrier diffusion and Auger recombination processes. The temporal
delay between the individual equal-energy fs-laser pulses was varied between
$0$ and $\sim 4$ ps for quantification of the transient carrier densities in
the conduction band of the laser-excited silicon. The results of the numerical
analysis reveal the importance of carrier generation and relaxation processes
in fs-LIPSS formation on silicon and quantitatively explain the two time
constants of the delay dependent decrease of the Low-Spatial-Frequency LIPSS
(LSFL) area observed experimentally. The role of carrier generation, diffusion
and recombination are quantified individually.


title:
Measurement of neutral current e+/-p cross sections at high Bjorken x
  with the ZEUS detector

abstract:
  The neutral current e+/-p cross section has been measured up to values of
Bjorken x of approximately 1 with the ZEUS detector at HERA using an integrated
luminosity of 187 inv. pb of e-p and 142 inv. pb of e+p collisions at sqrt(s) =
318GeV. Differential cross sections in x and Q2, the exchanged boson
virtuality, are presented for Q2 geq 725GeV2. An improved reconstruction method
and greatly increased amount of data allows a finer binning in the high-x
region of the neutral current cross section and leads to a measurement with
much improved precision compared to a similar earlier analysis. The
measurements are compared to Standard Model expectations based on a variety of
recent parton distribution functions.


title:
Magnetic penetration depth and vortex structure in anharmonic
  superconducting junctions with an interfacial pair breaking

abstract:
  The penetration depth l_j in superconducting junctions is identified within
the Ginzburg-Landau theory as a function of the interfacial pair breaking, of
the magnetic field and of the Josephson coupling strength. When the interfacial
pair breaking goes up, l_j increases and an applicability of the local
Josephson electrodynamics to junctions with a strong Josephson coupling is
extended. In the junctions with strongly anharmonic current-phase relations,
the magnetic field dependence of l_j is shown to lead to a significant
difference between the weak-field penetration depth and the characteristic size
of the Josephson vortex. For such junctions a nonmonotonic dependence of l_j
and of the lower critical field on the Josephson coupling constant is found,
and the specific features of spatial profiles of the supercurrent and the
magnetic field in the Josephson vortex are established.


title:
Comment on Masanari Asano et al. A model of epigenetic evolution based
  on theory of open quantum systems. Syst Synth Biol, 2013

abstract:
  The comment mostly concerns mis-representation of my position on Quantum
Biology, by stating that I am 'reducing cell's behavior to quantum particles
inside the cell'. I contrast my position with that of McFadden-Al-Khalili, as
well as with the position of Asano et al. I also advertise an idea, described
in our latest paper (Bordonaro, Ogryzko. Quantum Biology at the Cellular level
- elements of the research program, BioSystems, 2013), for the need of
synthetic biology in testing some predictions that follow from our approach.


title: Nuclear and gravitational energies in stars

abstract:
  The force that governs the evolution of stars is gravity. Indeed this force
drives star formation, imposes thermal and density gradients into stars at
hydrostatic equilibrium and finally plays the key role in the last phases of
their evolution. Nuclear power in stars governs their lifetimes and of course
the stellar nucleosynthesis. The nuclear reactions are at the heart of the
changes of composition of the baryonic matter in the Universe. This change of
composition, in its turn, has profound consequences on the evolution of stars
and galaxies.
  The energy extracted from the gravitational, respectively nuclear reservoirs
during the lifetimes of stars of different masses are estimated. It is shown
that low and intermediate mass stars (M < 8 Msol) extract roughly 90 times more
energy from their nuclear reservoir than from their gravitational one, while
massive stars (M > 8 Msol), which explode in a supernova explosion, extract
more than 5 times more energy from the gravitational reservoir than from the
nuclear one. We conclude by discussing a few important nuclear reactions and
their link to topical astrophysical questions.


title:
Study of Propagating Modes and Reflectivity in Bragg Filters with
  AlxGa1-xN/GaN Material Composition

abstract:
  In this paper, forward and backward propagating waves and reflectivity in an
optical waveguide structure namely the fiber Bragg reflector also considered as
a one dimensional photonic crystal, are analytically computed using coupled
mode theory for different grating lengths and coupling conditions.
AlxGa1-xN/GaN material composition is considered as unit block of the periodic
organization, and refractive index of AlxGa1-xN is taken to be dependent on
material composition, bandgap and operating wavelength following Adachis'
model. The structure being considered is the Bragg grating where increase in
grating length enhances the reflection of electromagnetic wave, and strong
coupling provides larger bandgap spectral width. Input wavelength is made
different from Bragg wavelength to study the characteristics of propagating
waves. A suitable combination of grating length and coupling coefficient is
helpful in designing the photonic bandgap at 1550 nm wavelength. These
characteristic curves can be utilized to study how waves propagate through the
optical waveguides which have a special place in optical communications


title: Pricing and Hedging Basket Options with Exact Moment Matching

abstract:
  Theoretical models applied to option pricing should take into account the
empirical characteristics of the underlying financial time series. In this
paper, we show how to price basket options when assets follow a shifted
log-normal process with jumps capable of accommodating negative skewness. Our
technique is based on the Hermite polynomial expansion that can match exactly
the first m moments of the model implied-probability distribution. This method
is shown to provide superior results for basket options not only with respect
to pricing but also for hedging.


title:
An initial-boundary value problem in a strip for a two-dimensional
  equation of Zakharov-Kuznetsov type

abstract:
  An initial-boundary value problem in a strip with homogeneous Diriclet
boundary conditions for two-dimensional generalized Zakharov-Kuznetsov equation
is considered. In particular, dissipative and absorbing degenerate terms can be
supplemented to the original Zakharov-Kuznetsov equation. Results on global
existence, uniqueness and long-time decay of weak silutions are established.


title:
IceCube, DeepCore, PINGU and the indirect search for supersymmetric dark
  matter

abstract:
  The discovery of a particle that could be the lightest CP-even Higgs of the
minimal supersymmetric extension of the Standard Model (MSSM) and the lack of
evidence so far for supersymmetry at the LHC have many profound implications,
including for the phenomenology of supersymmetric dark matter. In this study,
we re-evaluate and give an update on the prospects for detecting supersymmetric
neutralinos with neutrino telescopes, focussing in particular on the
IceCube/DeepCore Telescope as well as on its proposed extension, PINGU.
Searches for high-energy neutrinos from the Sun with IceCube probe MSSM
neutralino dark matter models with the correct Higgs mass in a significant way.
This is especially the case for neutralino dark matter models producing hard
neutrino spectra, across a wide range of masses, while PINGU is anticipated to
improve the detector sensitivity especially for models in the low neutralino
mass range.


title: Ising Model: Local Spin Correlations and Conformal Invariance

abstract:
  We study the 2-dimensional Ising model at critical temperature on a simply
connected subset $\Omega_{\delta}$ of the square grid $\delta\mathbb{Z}^{2}$.
The scaling limit of the critical Ising model is conjectured to be described by
Conformal Field Theory; in particular, there is expected to be a precise
correspondence between local lattice fields of the Ising model and the local
fields of Conformal Field Theory.
  Towards the proof of this correspondence, we analyze arbitrary spin pattern
probabilities (probabilities of finite spin configurations occurring at the
origin), explicitly obtain their infinite-volume limits, and prove their
conformal covariance at the first (non-trivial) order. We formulate these
probabilities in terms of discrete fermionic observables, enabling the study of
their scaling limits. This generalizes results of [Hon10,HoSm13] and [CHI15] to
one-point functions of any local spin correlations.
  We introduce a collection of tools which allow one to exactly and explicitly
translate any spin pattern probability (and hence any lattice local field
correlation) in terms of discrete complex analysis quantities. The proof
requires working with multipoint lattice spinors with monodromy (including
construction of explicit formulae in the full plane), and refined analysis near
their source points to prove convergence to the appropriate continuous
conformally covariant functions.


title: Falsifying High-Scale Leptogenesis at the LHC

abstract:
  Measuring a non-zero value for the cross section of any lepton number
violating (LNV) process would put a strong lower limit on the washout factor
for the effective lepton number density in the early universe at times close to
the electroweak phase transition and thus would lead to important constraints
on any high-scale model for the generation of the observed baryon asymmetry
based on LNV. In particular, for leptogenesis models with masses of the
right-handed neutrinos heavier than the mass scale observed at the LHC, the
implied large washout factors would lead to a violation of the
out-of-equilibrium condition and exponentially suppress the net lepton number
produced in such leptogenesis models. We thus demonstrate that the observation
of LNV processes at the LHC results in the falsification of high-scale
leptogenesis models. However, no conclusions about the viability of
leptogenesis models can be drawn from the non-observation of LNV processes.


title: Spectral distortions in the cosmic microwave background polarization

abstract:
  We compute the spectral distortions of the Cosmic Microwave Background (CMB)
polarization induced by non-linear effects in the Compton interactions between
CMB photons and cold intergalactic electrons. This signal is of the $y$-type
and is dominated by contributions arising from the reionized era. We stress
that it is not shadowed by the thermal SZ effect which has no equivalent for
polarization. We decompose its angular dependence into $E$- and $B$-modes, and
we calculate the corresponding power spectra, both exactly and using a suitable
Limber approximation that allows a simpler numerical evaluation. We find that
$B$-modes are of the same order of magnitude as $E$-modes. Both spectra are
relatively flat, peaking around $\ell=280$, and their overall amplitude is
directly related to the optical depth to reionization. Moreover, we find this
effect to be one order of magnitude larger than the non-linear kinetic
Sunyaev-Zel'dovich effect in galaxy clusters. Finally, we discuss how to
improve the detectability of our signal by cross-correlating it with other
quantities sourced by the flow of intergalactic electrons.


title:
Structural Properties of the Cambrian Semilattices -- Consequences of
  Semidistributivity

abstract:
  The $\gamma$-Cambrian semilattices $\mathcal{C}_{\gamma}$ defined by Reading
and Speyer are a family of meet-semilattices associated with a Coxeter group
$W$ and a Coxeter element $\gamma\in W$, and they are lattices if and only if
$W$ is finite. In the case where $W$ is the symmetric group $\mathfrak{S}_{n}$
and $\gamma$ is the long cycle $(1\;2\;\ldots\;n)$ the corresponding
$\gamma$-Cambrian lattice is isomorphic to the well-known Tamari lattice
$\mathcal{T}_{n}$. Recently, Kallipoliti and the author have investigated
$\mathcal{C}_{\gamma}$ from a topological viewpoint, and showed that many
properties of the Tamari lattices can be generalized nicely. In the present
article this investigation is continued on a structural level using the
observation of Reading and Speyer that $\mathcal{C}_{\gamma}$ is
semidistributive. First we prove that every closed interval of
$\mathcal{C}_{\gamma}$ is a bounded-homomorphic image of a free lattice (in
fact it is a so-called $\mathcal{H\!H}$-lattice). Subsequently we prove that
each closed interval of $\mathcal{C}_{\gamma}$ is trim, we determine its
breadth, and we characterize the closed intervals that are dismantlable.


title: How Many Ore-Bearing Asteroids?

abstract:
  A simple formalism is presented to assess how many asteroids contain ore,
i.e. commercially profitable material, and not merely a high concentration of a
resource. I apply this formalism to two resource cases: platinum group metals
(PGMs) and water. Assuming for now that only Ni-Fe asteroids are of interest
for PGMs, then 1% of NEOs are rich in PGMs. The dearth of ultra-low delta-v
(<4.5 km s-1) NEOs larger than 100 m diameter reduces the ore-bearing fraction
to only ~1 in 2000 NEOs. As 100 m diameter NEOs are needed to have a value >=
US$1 B and the population of near-Earth objects (NEOs) larger than 100 m
diameter is ~20,000 (Mainzer et al. 2011) the total population of PGM
ore-bearing NEOs is roughly 10. I stress that this is a conservative and highly
uncertain value. For example, an order of magnitude increase in PGM ore-bearing
NEOs occurs if delta-v can as large as 5.7 km s-1. Water ore for utilization in
space is likely to be found in ~1/1100 NEOs. NEOs as small as 18 m diameter can
be water-ore-bodies because of the high richness of water (~20%) expected in
~25% of carbonaceous asteroids, bringing the number of water-ore-bearing NEOs
to ~9000 out of the 10 million NEOs of this size. These small NEOs are,
however, hard to find with present surveys. There will be ~18 water-ore-bearing
NEOs >100 m diameter. These estimates are at present highly imprecise and
sensitive to small changes, especially in the maximum delta-v allowed.
Nonetheless the low values found here mean that much improved determinations of
each of the terms of the formalism are urgently needed. If better estimates
still find small numbers of ore-bearing NEOs then thorough surveys for NEA
discovery and, especially, characterization are needed. Strategies for the two
classes are likely to be different.


title: Low ionization lines in high luminosity quasars: The calcium triplet

abstract:
  In order to investigate where and how low ionization lines are emitted in
quasars we are studying a new collection of spectra of the CaII triplet at
$\lambda$8498, $\lambda$8542, $\lambda$8662 observed with the Very Large
Telescope (VLT) using the Infrared Spectrometer And Array Camera (ISAAC). Our
sample involves luminous quasars at intermediate redshift for which CaII
observations are almost nonexistent. We fit the CaII triplet and the OI
$\lambda$8446 line using the H$\beta$ profile as a model. We derive constraints
on the line emitting region from the relative strength of the CaII triplet, OI
$\lambda$8446 and H$\beta$.


title: How Many Assay Probes to Find One Ore-bearing Asteroid?

abstract:
  The number of ore-bearing asteroids could well be small and remote telescopic
techniques are inadequate to identify such asteroids confidently. Finding an
asteroid that can be profitably mined requires proximate observations from
assay probes. Here we use a simple statistical approach to estimate the number
of assay probes, Nassay, needed to find at least one ore-bearing asteroid at a
high confidence (90%, 95%, 99%). We present results for a wide range of values
of the probability of an asteroid being rich in the resource of interest,
Prich. We find that Nassay depends strongly on Prich, for likely values of
Prich (<0.5). For a plausible value of Prich~0.1 then to obtain 90% confidence
that at least one ore-bearing asteroid is found, Nassay = 22, and for 99%
confidence Nassay = 44. A factor two increase in Prich roughly halves Nassay,
while even for Prich~0.5, Nassay (90%) = 4. Hence any improvement in asteroid
characterization prior to sending probes to its proximity would be an effective
way to cost-effectively search for valuable resources among the asteroids. Some
possibilities for doing so are briefly discussed.


title:
Quantum probes of timelike naked singularities in the weak field regime
  of $f(R)$ global monopole spacetime

abstract:
  The formation of a naked singularity in $f(R)$ global monopole spacetime is
considered in view of quantum mechanics. Quantum test fields obeying the
Klein$-$Gordon, Dirac and Maxwell equations are used to probe the classical
timelike naked singularity developed at $r=0$. We prove that the spatial
derivative operator of the fields fails to be essentially self-adjoint. As a
result, the classical timelike naked singularity formed in $f(R)$ global
monopole spacetime remains quantum mechanically singular when it is probed with
quantum fields having different spin structures. Pitelli and Letelier (Phys.
Rev. D 80, 104035, 2009) had shown that for quantum scalar ($spin$ $0$% )
probes the general relativistic global monopole singularity remains intact. For
specific modes electromagnetic ($spin$ $1$) and Dirac field ($% spin$ $1/2$)
probes, however, we show that the global monopole spacetime behaves quantum
mechanically regular. The admissibility of this singularity is also
incorporated within the Gubser's singularity conjecture.


title: Exploiting Parallelism in Coalgebraic Logic Programming

abstract:
  We present a parallel implementation of Coalgebraic Logic Programming (CoALP)
in the programming language Go. CoALP was initially introduced to reflect
coalgebraic semantics of logic programming, with coalgebraic derivation
algorithm featuring both corecursion and parallelism. Here, we discuss how the
coalgebraic semantics influenced our parallel implementation of logic
programming.


title: The universe as quantum computer

abstract:
  This article reviews the history of digital computation, and investigates
just how far the concept of computation can be taken. In particular, I address
the question of whether the universe itself is in fact a giant computer, and if
so, just what kind of computer it is. I will show that the universe can be
regarded as a giant quantum computer. The quantum computational model of the
universe explains a variety of observed phenomena not encompassed by the
ordinary laws of physics. In particular, the model shows that the the quantum
computational universe automatically gives rise to a mix of randomness and
order, and to both simple and complex systems.


title: Uncomputability and physical law

abstract:
  This article addresses the question of when physical laws and their
consequences can be computed. If a physical system is capable of universal
computation, then its energy gap can't be computed. At an even more fundamental
level, the most concise, simply applicable formulation of the underlying laws
of physics is uncomputable. That is, physicists are in the same boat as
mathematicians: many quantities of interest can be computed, but not all.


title:
Weak and strong field approximations and circular orbits of
  Kehagias-Sfetsos space-time

abstract:
  The Kehagias-Sfetsos asymptotically flat black hole and naked singularity
solutions of Ho\v{r}ava-Lifshitz gravity are investigated both in the
weak-field and strong-field regimes. In the weak-field limit the gravitational
field generated by the Kehagias-Sfetsos spherically symmetric solution is
weaker then in the case of the Schwarzschild black hole of general relativity.
In the strong-field regime naked singularities with $\omega_{0} \ll 1 $ display
an unusual distance dependence: gravity becomes weaker when approaching the
singularity. The stability of circular orbits is also analyzed. While in the
black hole case the square of the angular momentum should be larger than a
certain finite, non-zero minimal value, in the naked singularity case there are
stable circular orbits for any non-zero value of the angular momentum. In this
regime we prove the existence of an infimum of the allowed radii of circular
orbits (corresponding to vanishing angular momentum).


title:
A new method to determine large scale structure from the luminosity
  distance

abstract:
  The luminosity distance can be used to determine the properties of large
scale structure around the observer. To this purpose we develop a new inversion
method to map luminosity distance to a LTB metric based on the use of the exact
analytical solution for Einstein equations. The main advantages of this
approach are an improved numerical accuracy and stability, an exact analytical
setting of the initial conditions for the differential equations which need to
be solved and the validity for any sign of the functions determining the LTB
geometry. Given the fully analytical form of the differential equations, this
method also simplifies the calculation of the red-shift expansion around the
apparent horizon point where the numerical solution becomes unstable. We test
the method by inverting the supernovae Ia luminosity distance function
corresponding to the the best fit $\Lambda CDM$ model. We find that only a
limited range of initial conditions is compatible with observations, or a
transition from red to blue shift can occur at relatively low redshift. Despite
LTB solutions without a cosmological constant have been shown not to be
compatible with all different set of available observational data, those
studies normally fit data assuming a special functional ansatz for the
inhomogeneity profile, which often depend only on few parameters. Inversion
methods on the contrary are able to fully explore the freedom in fixing the
functions which determine a LTB solution. Another important possible
application is not about LTB solutions as cosmological models, but rather as
tools to study the effects on the observations made by a generic observer
located in an inhomogeneous region of the Universe where a fully non
perturbative treatment involving exact solutions of Einstein equations is
required.


title: Invited review: Graphite and its hidden superconductivity

abstract:
  We review experimental results, from transport to magnetization measurements,
on different graphite samples, from bulk oriented graphite, thin graphite films
to transmission electron microscope lamellae, that indicate the existence of
granular superconductivity at temperatures above 100 K. The accumulated
evidence speaks for a localization of the superconducting phase(s) at certain
interfaces embedded in semiconducting crystalline regions with Bernal stacking
order.


title: MCgrid: projecting cross section calculations on grids

abstract:
  MCgrid is a software package that provides access to the APPLgrid
interpolation tool for Monte Carlo event generator codes, allowing for fast and
flexible variations of scales, coupling parameters and PDFs in cutting edge
leading and next-to-leading-order QCD calculations. This is achieved by
providing additional tools to the Rivet analysis system for the construction of
MCgrid enhanced Rivet analyses. The interface is based around a one-to-one
correspondence between a Rivet histogram class and a wrapper for an APPLgrid
interpolation grid. The Rivet system provides all of the analysis tools
required to project a Monte Carlo weight upon an observable bin, and the MCgrid
package provides the correct conversion of the event weight to an APPLgrid fill
call. MCgrid has been tested and designed for use with the SHERPA event
generator, however as with Rivet the package is suitable for use with any code
which can produce events in the HepMC event record format.


title:
Low-Rank Approximations for Conditional Feedforward Computation in Deep
  Neural Networks

abstract:
  Scalability properties of deep neural networks raise key research questions,
particularly as the problems considered become larger and more challenging.
This paper expands on the idea of conditional computation introduced by Bengio,
et. al., where the nodes of a deep network are augmented by a set of gating
units that determine when a node should be calculated. By factorizing the
weight matrix into a low-rank approximation, an estimation of the sign of the
pre-nonlinearity activation can be efficiently obtained. For networks using
rectified-linear hidden units, this implies that the computation of a hidden
unit with an estimated negative pre-nonlinearity can be ommitted altogether, as
its value will become zero when nonlinearity is applied. For sparse neural
networks, this can result in considerable speed gains. Experimental results
using the MNIST and SVHN data sets with a fully-connected deep neural network
demonstrate the performance robustness of the proposed scheme with respect to
the error introduced by the conditional computation process.


title: Inseparability criteria based on bipartitions of $N$-spin systems

abstract:
  We present a new set of inseparabilty inequalities to detect entanglement in
$N$-spin states. These are based on negative partial transposition and involve
collective spin-spin correlations of any two partitions of the entire system.
They also reveal the rich texture of partial separability for different
partition and can discriminate between GHZ-type and W-type entanglement, as
well. We introduce a new concept of relative entanglement of two different
systems and two different partitions in a spin-ensemble. These criteria can be
applicable to non-symmetric states and states with odd or even $N$.


title:
Explicit versions of the prime ideal theorem for Dedekind zeta functions
  under GRH

abstract:
  Let $\psi_\K$ be the Chebyshev function of a number field $\K$. Under GRH we
prove an explicit upper bound for $|\psi_\K(x)-x|$ in terms of the degree and
the discriminant of $\K$. The new bound improves significantly on previous
known results.


title: Neutron Star masses from the Field Correlator Method Equation of State

abstract:
  We analyse the hadron-quark phase transition in neutron stars by confronting
the hadronic Equation of State (EoS) obtained according to the microscopic
Brueckner-Hartree-Fock many body theory, with the quark matter EoS derived
within the Field Correlator Method. In particular, the latter EoS is only
parametrized in terms of the gluon condensate and the large distance
quark-antiquark potential, so that the comparison of the results of this
analysis with the most recent measurements of heavy neutron star masses
provides some physical constraints on these two parameters.


title: Explicit smoothed prime ideals theorems under GRH

abstract:
  Let $\psi_{\mathbb K}$ be the Chebyshev function of a number field $\mathbb
K$. Let $\psi^{(1)}_{\mathbb K}(x):=\int_{0}^{x}\psi_{\mathbb K}(t)\,d t$ and
$\psi^{(2)}_{\mathbb K}(x):=2\int_{0}^{x}\psi^{(1)}_{\mathbb K}(t)\,d t$. We
prove under GRH explicit inequalities for the differences $|\psi^{(1)}_{\mathbb
K}(x) - \tfrac{x^2}{2}|$ and $|\psi^{(2)}_{\mathbb K}(x) - \tfrac{x^3}{3}|$. We
deduce an efficient algorithm for the computation of the residue of the
Dedekind zeta function and a bound on small-norm prime ideals.


title: Optical conductivity of nodal metals

abstract:
  Fermi liquid theory is remarkably successful in describing the transport and
optical properties of metals; at frequencies higher than the scattering rate,
the optical conductivity adopts the well-known power law behavior
$\sigma_1(\omega) \propto \omega^{-2}$. We have observed an unusual non-Fermi
liquid response $\sigma_1(\omega) \propto \omega^{-1\pm 0.2}$ in the ground
states of several cuprate and iron-based materials which undergo electronic or
magnetic phase transitions resulting in dramatically reduced or nodal Fermi
surfaces. The identification of an inverse (or fractional) power-law behavior
in the residual optical conductivity now permits the removal of this
contribution, revealing the direct transitions across the gap and allowing the
nature of the electron-boson coupling to be probed. The non-Fermi liquid
behavior in these systems may be the result of a common Fermi surface topology
of Dirac cone-like features in the electronic dispersion.


title:
Hyperon-nucleon interaction and baryonic contact terms in SU(3) chiral
  effective field theory

abstract:
  In this proceeding we summarize results for baryonic contact terms derived
within SU(3) chiral effective field theory. The four-baryon contact terms,
necessary for the description of the hyperon-nucleon interaction, include SU(3)
symmetric and explicit chiral symmetry breaking terms. They also include
four-baryon contact terms involving pseudoscalar mesons, which become important
for three-body forces. Furthermore we derive the leading order six-baryon
contact terms in the non-relativistic limit and study their contribution to the
$\Lambda NN$ three-body contact interaction. These results could play an
important role in studies of hypernuclei or hyperons in nuclear matter.


title: Extremality for Gallager's Reliability Function $E_0$

abstract:
  We describe certain extremalities for Gallager's $E_0$ function evaluated
under the uniform input distribution for binary input discrete memoryless
channels. The results characterize the extremality of the $E_0(\rho)$ curves of
the binary erasure channel and the binary symmetric channel among all the
$E_0(\rho)$ curves that can be generated by the class of binary discrete
memoryless channels whose $E_0(\rho)$ curves pass through a given point
$(\rho_0, e_0)$, for some $\rho_0 > -1$.


title:
Measurement of sub-pulse-width temporal delays via spectral interference
  induced by weak value amplification

abstract:
  We demonstrate experimentally a scheme to measure small temporal delays, much
smaller than the pulse width, between optical pulses. Specifically, we observe
an interference effect, based on the concepts of quantum weak measurements and
weak value amplification, through which a sub-pulsewidth temporal delay between
two femtosecond pulses induces a measurable shift of the central frequency of
the pulse. The amount of frequency shift, and the accompanying losses of the
measurement, can be tailored by post-selecting different states of
polarization. Our scheme requires only spectrum measurements and linear optics
elements, hence greatly facilitating its implementation. Thus it appears as a
promising technique for measuring small and rapidly varying temporal delays.


title: Abnormal Superfluid Fraction of Harmonically Trapped Few-Fermion Systems

abstract:
  Superfluidity is a fascinating phenomenon that, at the macroscopic scale,
leads to dissipationless flow and the emergence of vortices. While these
macroscopic manifestations of superfluidity are well described by theories that
have their origin in Landau's two-fluid model, our microscopic understanding of
superfluidity is far from complete. Using analytical and numerical \textit{ab
initio} approaches, this paper determines the superfluid fraction and local
superfluid density of small harmonically trapped two-component Fermi gases as a
function of the interaction strength and temperature. At low temperature, we
find that the superfluid fraction is, in certain regions of the parameter
space, negative. This counterintuitive finding is traced back to the symmetry
of the system's ground state wave function, which gives rise to a diverging
quantum moment of inertia $I_{\text{q}}$. Analogous abnormal behavior of
$I_{\text{q}}$ has been observed in even-odd nuclei at low temperature. Our
predictions can be tested in modern cold atom experiments.


title:
Partial regularity for minimizers of singular energy functionals, with
  application to liquid crystal models

abstract:
  We study the partial regularity of minimizers for certain singular
functionals in the calculus of variations, motivated by Ball and Majumdar's
recent modification [BM] of the Landau-de Gennes energy functional.


title:
Optimal designs for multi-response generalized linear models with
  applications in thermal spraying

abstract:
  We consider the problem of designing experiments for investigating particle
in-flight properties in thermal spraying. Observations are available on an
extensive design for an initial day and thereafter in limited number for any
particular day. Generalized linear models including additional day effects are
used for analyzing the process, where the models vary with respect to different
responses. We construct robust D-optimal designs to collect additional data on
any current day, which are efficient for the estimation of the parameters in
all models under consideration. These designs improve a reference fractional
factorial design substantially. We also investigate designs, which maximize the
power of the test for an additional day effect. The results are used to design
additional experiments of the thermal spraying process and a comparison of the
statistical analysis based on a reference design as well as on a selected
D-optimal design is performed.


title:
On the influence of molecular structure on the conductivity of
  electrolyte solutions - sodium nitrate in water

abstract:
  Theoretical calculations of the conductivity of sodium nitrate in water are
presented and compared with experimental measurements. The method of direct
correlation force in the framework of the interionic theory is used for the
calculation of transport properties in connection with the associative mean
spherical approximation (AMSA). The effective interactions between ions in
solutions are derived with the help of Monte Carlo and Molecular Dynamics
calculations on the Born-Oppenheimer level. This work is based on earlier
theoretical and experimental studies of the structure of concentrated aqueous
sodium nitrate solutions.


title: Dive into the heart of red giant stars to better understand our Galaxy

abstract:
  The availability of asteroseismic constrains for of large sample of stars
observed with CoRoT and Kepler paves the way for statistical studies of the
seismic properties of stellar populations, and becomes a powerful tool to
better understand stellar structure and evolution. Here I present predictions
of stellar models computed with the code STAREVOL including thermohaline mixing
together with rotational mixing. I compare the theoretical predictions for the
chemical properties of stars with recent spectroscopic of both field and
cluster stars observations, and discuss the effects of both mechanisms on
asteroseismic diagnostics, as well as on Galactic chemical evolution of
helium-3.


title: Almost split sequences for Knorr lattices

abstract:
  Let $O$ be a complete d.v.r. and $G$ a finite group. We give two applications
of an adjunction in the stable category of $OG$. The first application gives
necessary and sufficient conditions for the middle term of an almost split
sequence terminating in a Knorr lattice to be indecomposable.
  The second characterises the stable endomorphism rings of Heller lattices of
kG-modules.


title:
Social Media Monitoring of the Campaigns for the 2013 German Bundestag
  Elections on Facebook and Twitter

abstract:
  As more and more people use social media to communicate their view and
perception of elections, researchers have increasingly been collecting and
analyzing data from social media platforms. Our research focuses on social
media communication related to the 2013 election of the German parlia-ment
[translation: Bundestagswahl 2013]. We constructed several social media
datasets using data from Facebook and Twitter. First, we identified the most
relevant candidates (n=2,346) and checked whether they maintained social media
accounts. The Facebook data was collected in November 2013 for the period of
January 2009 to October 2013. On Facebook we identified 1,408 Facebook walls
containing approximately 469,000 posts. Twitter data was collected between June
and December 2013 finishing with the constitution of the government. On Twitter
we identified 1,009 candidates and 76 other agents, for example, journalists.
We estimated the number of relevant tweets to exceed eight million for the
period from July 27 to September 27 alone. In this document we summarize past
research in the literature, discuss possibilities for research with our data
set, explain the data collection procedures, and provide a description of the
data and a discussion of issues for archiving and dissemination of social media
data.


title: GCG: Mining Maximal Complete Graph Patterns from Large Spatial Data

abstract:
  Recent research on pattern discovery has progressed from mining frequent
patterns and sequences to mining structured patterns, such as trees and graphs.
Graphs as general data structure can model complex relations among data with
wide applications in web exploration and social networks. However, the process
of mining large graph patterns is a challenge due to the existence of large
number of subgraphs. In this paper, we aim to mine only frequent complete graph
patterns. A graph g in a database is complete if every pair of distinct
vertices is connected by a unique edge. Grid Complete Graph (GCG) is a mining
algorithm developed to explore interesting pruning techniques to extract
maximal complete graphs from large spatial dataset existing in Sloan Digital
Sky Survey (SDSS) data. Using a divide and conquer strategy, GCG shows high
efficiency especially in the presence of large number of patterns. In this
paper, we describe GCG that can mine not only simple co-location spatial
patterns but also complex ones. To the best of our knowledge, this is the first
algorithm used to exploit the extraction of maximal complete graphs in the
process of mining complex co-location patterns in large spatial dataset.


title:
Atlas and wavenumber tables for visible part of the multiline
  electronic-vibro-rotational emission spectrum of the $D_2$ molecule measured
  with moderate resolution in deuterium plasma with minor hydrogen impurity

abstract:
  The visible part ($\approx 419-696$ nm) of the multiline
electronic-vibro-rotational emission spectrum of the $D_2$ molecule was
recorded with moderate resolution mainly limited by Doppler broadening of
spectral lines (line widths FWHM less than $0.013$ nm). After numerical
deconvolution of the recorded intensity distributions and proper calibration of
the spectrometer the new set of wavenumber values was obtained. It is shown
that new data are significantly more precise than those available for visible
part of the $D_2$ spectrum. Final results are reported as a supplement in the
form of an atlas divided into 158 sections (each section covers about 1.5 nm)
containing pictures of images in the focal plane of the spectrometer, intensity
distributions in linear and logarithmic scales and the table containing
wavenumber and relative intensity values for 11941 spectral lines together with
available and new line assignments for the $D_2$ and $HD$ molecules.


title:
Parametric Modelling of Multivariate Count Data Using Probabilistic
  Graphical Models

abstract:
  Multivariate count data are defined as the number of items of different
categories issued from sampling within a population, which individuals are
grouped into categories. The analysis of multivariate count data is a recurrent
and crucial issue in numerous modelling problems, particularly in the fields of
biology and ecology (where the data can represent, for example, children counts
associated with multitype branching processes), sociology and econometrics. We
focus on I) Identifying categories that appear simultaneously, or on the
contrary that are mutually exclusive. This is achieved by identifying
conditional independence relationships between the variables; II)Building
parsimonious parametric models consistent with these relationships; III)
Characterising and testing the effects of covariates on the joint distribution
of the counts. To achieve these goals, we propose an approach based on
graphical probabilistic models, and more specifically partially directed
acyclic graphs.


title: Quasimodes and unstability for linear Schr\^odinger equation

abstract:
  We consider the evolution operator exp(-it(-Delta+V)) associated with a
Schr\"odinger operator on a Riemannian manifold (M,g). We are interested in the
dependence of this operator on V running in L^p(M). Under a geometrical
hypothetis, we show the unstability for p


title:
Conservative and non-conservative methods based on hermite weighted
  essentially-non-oscillatory reconstruction for Vlasov equations

abstract:
  We introduce a WENO reconstruction based on Hermite interpolation both for
semi-Lagrangian and finite difference methods. This WENO reconstruction
technique allows to control spurious oscillations. We develop third and fifth
order methods and apply them to non-conservative semi-Lagrangian schemes and
conservative finite difference methods. Our numerical results will be compared
to the usual semi-Lagrangian method with cubic spline reconstruction and the
classical fifth order WENO finite difference scheme. These reconstructions are
observed to be less dissipative than the usual weighted essentially non-
oscillatory procedure. We apply these methods to transport equations in the
context of plasma physics and the numerical simulation of turbulence phenomena.


title: Selective adsorption of ions in charged slit-systems

abstract:
  We study the selective adsorption of various cations into a layered slit
system using grand canonical Monte Carlo simulations. The slit system is formed
by a series of negatively charged membranes. The electrolyte contains two kinds
of cations with different sizes and valences modelled by charged hard spheres
immersed in a continuum dielectric solvent. We present the results for various
cases depending on the combinations of the properties of the competing cations.
We concentrate on the case when the divalent cations are larger than the
monovalent cations. In this case, size and charge have counterbalancing
effects, which results in interesting selectivity phenomena.


title: Local Energy Decay for the Damped Wave Equation

abstract:
  We prove local energy decay for the damped wave equation on R^d. The problem
which we consider is given by a long range metric perturbation of the Euclidean
Laplacian with a short range absorption index. Under a geometric control
assumption on the dissipation we obtain an almost optimal polynomial decay for
the energy in suitable weighted spaces. The proof relies on uniform estimates
for the corresponding "resolvent", both for low and high frequencies. These
estimates are given by an improved dissipative version of Mourre's commutators
method.


title:
Seismic reliability assessment of classical columns subjected to
  near-fault ground motions

abstract:
  A methodology for the performance-based seismic risk assessment of classical
columns is presented. Despite their apparent instability, classical columns
are, in general, earthquake resistant, as proven from the fact that many
classical monuments have survived many strong earthquakes over the centuries.
Nevertheless, the quantitative assessment of their reliability and the
understanding of their dynamic behavior are not easy, because of the
fundamental nonlinear character and the sensitivity of their response. In this
paper, a seismic risk assessment is performed for a multidrum column using
Monte Carlo simulation with synthetic ground motions. The ground motions
adopted contain a high- and low-frequency component, combining the stochastic
method, and a simple analytical pulse model to simulate the directivity pulse
contained in near source ground motions. The deterministic model for the
numerical analysis of the system is three-dimensional and is based on the
Discrete Element Method. Fragility curves are produced conditional on magnitude
and distance from the fault and also on scalar intensity measures for two
engineering demand parameters, one concerning the intensity of the response
during the ground shaking and the other the residual deformation of the column.
Three performance levels are assigned to each engineering demand parameter.
Fragility analysis demonstrated some of the salient features of these spinal
systems under near-fault seismic excitations, as for example, their decreased
vulnerability for very strong earthquakes of magnitude 7 or larger. The
analysis provides useful results regarding the seismic reliability of classical
monuments and decision making during restoration process.


title: Yamada-Watanabe results for stochastic differential equations with jumps

abstract:
  Recently, Kurtz (2007, 2014) obtained a general version of the
Yamada-Watanabe and Engelbert theorems relating existence and uniqueness of
weak and strong solutions of stochastic equations covering also the case of
stochastic differential equations with jumps. Following the original method of
Yamada and Watanabe (1971), we give alternative proofs for the following two
statements: pathwise uniqueness implies uniqueness in the sense of probability
law, and weak existence together with pathwise uniqueness imply strong
existence for stochastic differential equations with jumps.