title: Pre-adjunctions and the Ramsey property

abstract:
  Showing that the Ramsey property holds for a class of finite structures can
be an extremely challenging task and a slew of sophisticated methods have been
proposed in literature. In this paper we propose a new strategy to show that a
class of structures has the Ramsey property. The strategy is based on a
relatively simple result in category theory and consists of establishing a
pre-adjunction between the category of structures which is known to have the
Ramsey property, and the category of structures we are interested in. This
strategy was implicitly used already in 1981 by H.J. Pr\"omel and B. Voigt in
their proof of the Ramsey property for the class of finite linearly ordered
graphs. We demonstrate the applicability of this strategy by providing short
proofs of three important well known results: we show the Ramsey property for
the category of all finite linearly ordered posets with embeddings, for the
category of finite convexly ordered ultrametric spaces with embeddings, and for
the category of all finite linearly ordered metric spaces (rational metric
spaces) with embeddings.


title: Collective Coordinates in One-Dimensional Soliton Models Revisited

abstract:
  We compare numerical solutions to the full field equations to simplified
approaches based on implementing three collective coordinates for kink-antikink
interactions within the $\varphi^4$ and $\phi^6$ models in one time and one
space dimensions. We particularly pursue the question whether the collective
coordinate approximation substantiates the conjecture that vibrational modes
are important for resonance structures to occur in kink-antikink scattering.


title: Revisiting gravitino dark matter in thermal leptogenesis

abstract:
  In this paper, we revisit the gravitino dark matter scenario in the presence
of the bilinear $R$-parity violating interaction. In particular, we discuss a
consistency with the thermal leptogenesis. For a high reheating temperature
required for the thermal leptogenesis, the gravitino dark matter tends to be
overproduced, which puts a severe upper limit on the gluino mass. As we will
show, a large portion of parameter space of the gravitino dark matter scenario
has been excluded by combining the constraints from the gravitino abundance and
the null results of the searches for the superparticles at the LHC experiments.
In particular, the models with the stau (and other charged slepton) NLSP has
been almost excluded by the searches for the long-lived charged particles at
the LHC unless the required reheating temperature is somewhat lowered by
assuming, for example, a degenerated right-handed neutrino mass spectrum.


title: Experimental time-optimal universal control of spin qubits in solids

abstract:
  Quantum control of systems plays important roles in modern science and
technology. The ultimate goal of quantum control is to achieve high fidelity
universal control in the time-optimal way. Although high fidelity universal
control has been reported in various quantum systems, experimental
implementation of time-optimal universal control remains elusive. Here we
report the experimental realization of time-optimal universal control of spin
qubits in diamond. By generalizing a recent method for solving quantum
brachistochrone equations [X. Wang, et al., Phys. Rev. Lett. 114, 170501
(2015)], we obtained accurate minimum time protocols for multiple qubits with
fixed qubits' interactions and constrained control field. Single- and two-qubit
time-optimal gates are experimentally implemented with fidelities of 99%
obtained via quantum process tomography. Our work provides a time-optimal route
to achieve accurate quantum control, and unlocks new capabilities for emerging
field of time-optimal control in general quantum systems.


title:
Stripe and short range order in the charge density wave of
  1T-Cu$_x$TiSe$_2$

abstract:
  We study the impact of Cu intercalation on the charge density wave (CDW) in
1T-Cu$_{\text{x}}$TiSe$_{\text{2}}$ by scanning tunneling microscopy and
spectroscopy. Cu atoms, identified through density functional theory modeling,
are found to intercalate randomly on the octahedral site in the van der Waals
gap and to dope delocalized electrons near the Fermi level. While the CDW
modulation period does not depend on Cu content, we observe the formation of
charge stripe domains at low Cu content (x$<$0.02) and a breaking up of the
commensurate order into 2$\times$2 domains at higher Cu content. The latter
shrink with increasing Cu concentration and tend to be phase-shifted. These
findings invalidate a proposed excitonic pairing as the primary CDW formation
mechanism in this material.


title:
High-temperature expansion for frustrated magnets: Application to the
  J1-J2 model on the BCC lattice

abstract:
  We present the high-temperature expansion up to 11th order for the specific
heat $C$ and the uniform susceptibility $\chi_0$ and up to 9th order for the
structure factor $S_{\bf Q}$ of the frustrated spin-half $J_1$-$J_2$ Heisenberg
model on the BCC lattice. We consider ferromagnetic as well as
antiferromagnetic nearest-neighbor exchange $J_1$ and frustrating
antiferromagnetic next-nearest-neighbor exchange $J_2$. We discuss the
influence of frustration on the temperature dependence of these quantities.
Furthermore, we use the HTE series to determine the critical temperature $T_c$
as a function of the frustration parameter $J_2$.


title:
Deep-Learned Collision Avoidance Policy for Distributed Multi-Agent
  Navigation

abstract:
  High-speed, low-latency obstacle avoidance that is insensitive to sensor
noise is essential for enabling multiple decentralized robots to function
reliably in cluttered and dynamic environments. While other distributed
multi-agent collision avoidance systems exist, these systems require online
geometric optimization where tedious parameter tuning and perfect sensing are
necessary.
  We present a novel end-to-end framework to generate reactive collision
avoidance policy for efficient distributed multi-agent navigation. Our method
formulates an agent's navigation strategy as a deep neural network mapping from
the observed noisy sensor measurements to the agent's steering commands in
terms of movement velocity. We train the network on a large number of frames of
collision avoidance data collected by repeatedly running a multi-agent
simulator with different parameter settings. We validate the learned deep
neural network policy in a set of simulated and real scenarios with noisy
measurements and demonstrate that our method is able to generate a robust
navigation strategy that is insensitive to imperfect sensing and works reliably
in all situations. We also show that our method can be well generalized to
scenarios that do not appear in our training data, including scenes with static
obstacles and agents with different sizes. Videos are available at
https://sites.google.com/view/deepmaca.


title:
A Spectral Projection Preconditioner for Solving Ill Conditioned Linear
  Systems

abstract:
  We present a preconditioner based on spectral projection that is combined
with a deflated Krylov subspace method for solving ill conditioned linear
systems of equations. Our results show that the proposed algorithm requires
many fewer iterations to achieve the convergence criterion for solving an ill
conditioned problem than a Krylov subspace solver. In our numerical
experiments, the solution obtained by the proposed algorithm is more accurate
in terms of the norm of the distance to the exact solution of the linear system
of equations.


title: Exact Sampling from Determinantal Point Processes

abstract:
  Determinantal point processes (DPPs) are an important concept in random
matrix theory and combinatorics. They have also recently attracted interest in
the study of numerical methods for machine learning, as they offer an elegant
"missing link" between independent Monte Carlo sampling and deterministic
evaluation on regular grids, applicable to a general set of spaces. This is
helpful whenever an algorithm explores to reduce uncertainty, such as in active
learning, Bayesian optimization, reinforcement learning, and marginalization in
graphical models. To draw samples from a DPP in practice, existing literature
focuses on approximate schemes of low cost, or comparably inefficient exact
algorithms like rejection sampling. We point out that, for many settings of
relevance to machine learning, it is also possible to draw exact samples from
DPPs on continuous domains. We start from an intuitive example on the real
line, which is then generalized to multivariate real vector spaces. We also
compare to previously studied approximations, showing that exact sampling,
despite higher cost, can be preferable where precision is needed.


title:
PSVR - Self-stabilizing Publish/Subscribe Communication for Ad-hoc
  Networks

abstract:
  This paper presents the novel routing algorithm PSVR for pub/sub systems in
ad-hoc networks. Its focus is on scenarios where communications links are
unstable and nodes frequently change subscriptions. PSVR presents a compromise
of size and maintenance effort for routing tables due to sub- and
unsubscriptions and the length of routing paths. Designed in a self-stabilizing
manner it scales well with network size. The evaluation reveals that PSVR only
needs slightly more messages than a close to optimal routing structure for
publication delivery, and creates shorter routing paths than an existing
self-stabilizing algorithm. A real world deployment shows the usability of the
approach


title:
Efficient big data assimilation through sparse representation: A 3D
  benchmark case study in seismic history matching

abstract:
  In a previous work \citep{luo2016sparse2d_spej}, the authors proposed an
ensemble-based 4D seismic history matching (SHM) framework, which has some
relatively new ingredients, in terms of the type of seismic data in choice, the
way to handle big seismic data and related data noise estimation, and the use
of a recently developed iterative ensemble history matching algorithm.
  In seismic history matching, it is customary to use inverted seismic
attributes, such as acoustic impedance, as the observed data. In doing so,
extra uncertainties may arise during the inversion processes. The proposed SHM
framework avoids such intermediate inversion processes by adopting amplitude
versus angle (AVA) data. In addition, SHM typically involves assimilating a
large amount of observed seismic attributes into reservoir models. To handle
the big-data problem in SHM, the proposed framework adopts the following
wavelet-based sparse representation procedure: First, a discrete wavelet
transform is applied to observed seismic attributes. Then, uncertainty analysis
is conducted in the wavelet domain to estimate noise in the resulting wavelet
coefficients, and to calculate a corresponding threshold value. Wavelet
coefficients above the threshold value, called leading wavelet coefficients
hereafter, are used as the data for history matching. The retained leading
wavelet coefficients preserve the most salient features of the observed seismic
attributes, whereas rendering a substantially smaller data size. Finally, an
iterative ensemble smoother is adopted to update reservoir models, in such a
way that the leading wavelet coefficients of simulated seismic attributes
better match those of observed seismic attributes.
  (The rest of the abstract was omitted for the length restriction.)

categories: physics.data-an math.NA math.OC physics.geo-ph stat.CO


title:
Fluctuations in protein aggregation: Design of preclinical screening for
  early diagnosis of neurodegenerative disease

abstract:
  Autocatalytic fibril nucleation has recently been proposed to be a
determining factor for the spread of neurodegenerative diseases, but the same
process could also be exploited to amplify minute quantities of protein
aggregates in a diagnostic context. Recent advances in microfluidic technology
allow analysis of protein aggregation in micron-scale samples potentially
enabling such diagnostic approaches, but the theoretical foundations for the
analysis and interpretation of such data are so far lacking. Here we study
computationally the onset of protein aggregation in small volumes and show that
the process is ruled by intrinsic fluctuations whose volume dependent
distribution we also estimate theoretically. Based on these results, we develop
a strategy to quantify in silico the statistical errors associated with the
detection of aggregate containing samples. Our work opens a new perspective on
the forecasting of protein aggregation in asymptomatic subjects.


title: Posted Pricing sans Discrimination

abstract:
  In the quest for market mechanisms that are easy to implement, yet close to
optimal, few seem as viable as posted pricing. Despite the growing body of
impressive results, the performance of most posted price mechanisms however,
rely crucially on price discrimination when multiple copies of a good are
available. For the more general case with non-linear production costs on each
good, hardly anything is known for general multi-good markets. With this in
mind, we study a Bayesian setting where the seller can produce any number of
copies of a good but faces convex production costs for the same, and buyers
arrive sequentially. Our main contribution is a framework for
non-discriminatory pricing in the presence of production costs: the framework
yields posted price mechanisms with O(1)-approximation factors for fractionally
subadditive (XoS) buyers, logarithmic approximations for subadditive buyers,
and also extends to settings where the seller is oblivious to buyer valuations.
Our work presents the first known results for Bayesian settings with production
costs and is among the few posted price mechanisms that do not charge buyers
differently for the same good.


title: On the usability of deep networks for object-based image analysis

abstract:
  As computer vision before, remote sensing has been radically changed by the
introduction of Convolution Neural Networks. Land cover use, object detection
and scene understanding in aerial images rely more and more on deep learning to
achieve new state-of-the-art results. Recent architectures such as Fully
Convolutional Networks (Long et al., 2015) can even produce pixel level
annotations for semantic mapping. In this work, we show how to use such deep
networks to detect, segment and classify different varieties of wheeled
vehicles in aerial images from the ISPRS Potsdam dataset. This allows us to
tackle object detection and classification on a complex dataset made up of
visually similar classes, and to demonstrate the relevance of such a subclass
modeling approach. Especially, we want to show that deep learning is also
suitable for object-oriented analysis of Earth Observation data. First, we
train a FCN variant on the ISPRS Potsdam dataset and show how the learnt
semantic maps can be used to extract precise segmentation of vehicles, which
allow us studying the repartition of vehicles in the city. Second, we train a
CNN to perform vehicle classification on the VEDAI (Razakarivony and Jurie,
2016) dataset, and transfer its knowledge to classify candidate segmented
vehicles on the Potsdam dataset.


title:
Semantic Segmentation of Earth Observation Data Using Multimodal and
  Multi-scale Deep Networks

abstract:
  This work investigates the use of deep fully convolutional neural networks
(DFCNN) for pixel-wise scene labeling of Earth Observation images. Especially,
we train a variant of the SegNet architecture on remote sensing data over an
urban area and study different strategies for performing accurate semantic
segmentation. Our contributions are the following: 1) we transfer efficiently a
DFCNN from generic everyday images to remote sensing images; 2) we introduce a
multi-kernel convolutional layer for fast aggregation of predictions at
multiple scales; 3) we perform data fusion from heterogeneous sensors (optical
and laser) using residual correction. Our framework improves state-of-the-art
accuracy on the ISPRS Vaihingen 2D Semantic Labeling dataset.


title: Deformation and fracture of echinoderm collagen networks

abstract:
  Collagen networks provide the main structural component of most tissues and
represent an important ingredient for bio-mimetic materials for bio-medical
applications. Here we study the mechanical properties of stiff collagen
networks derived from three different echinoderms and show that they exhibit
non-linear stiffening followed by brittle fracture. The disordered nature of
the network leads to strong sample-to-sample fluctuations in elasticity and
fracture strength. We perform numerical simulations of a three dimensional
model for the deformation of a cross-linked elastic fibril network which is
able to reproduce the macroscopic features of the experimental results and
provide insights into the internal mechanics of stiff collagen networks. Our
numerical model provides an avenue for the design of collagen membranes with
tunable mechanical properties.


title: Production-Driven Patch Generation and Validation

abstract:
  We envision a world where the developer would receive each morning in her
GitHub dashboard a list of potential patches that fix certain production
failures. For this, we propose a novel program repair scheme, with the unique
feature of being applicable to production directly. We present the design and
implementation of a prototype system for Java, called Itzal, that performs
patch generation for uncaught exceptions in production. We have performed two
empirical experiments to validate our system: the first one on 34 failures from
14 different software applications, the second one on 16 seeded failures in 3
real open-source e-commerce applications for which we have set up a realistic
user traffic. This validates the novel and disruptive idea of using program
repair directly in production.


title:
Existence of solutions for a class of fourth order cross-diffusion
  systems of gradient flow type

abstract:
  This article is concerned with the existence and the long time behavior of
weak solutions to certain coupled systems of fourth-order degenerate parabolic
equations of gradient flow type. The underlying metric is a Wasserstein-like
transportation distance for vector-valued functions, with nonlinear mobilities
in each component. Under the hypothesis of (flat) convexity of the driving free
energy functional, weak solutions are constructed by means of the variational
minimizing movement scheme for metric gradient flows. The essential regularity
estimates are derived by variational methods.


title: Resistivity Minimum in Granular Composites and Thin Metallic Films

abstract:
  We analyze the temperature dependence of conductivity in thick granular
ferromagnetic compounds NiSiO2 and in thin weakly coupled films of Fe, Ni and
Py in vicinity of metal-insulator transition. Development of resistivity
minimum followed by a logarithmic variation of conductivity at lower
temperatures is attributed to granular structure of compounds and thin films
fabricated by conventional deposition techniques. Resistivity minimum is
identified as a transition between temperature dependent intra-granular
metallic conductance and thermally activated inter-granular tunneling.


title: Long cycles in locally expanding graphs, with applications

abstract:
  We provide sufficient conditions for the existence of long cycles in locally
expanding graphs, and present applications of our conditions and techniques to
Ramsey theory, random graphs and positional games.


title: Criticality in Two-Dimensional Quantum Systems: Tensor Network Approach

abstract:
  Determination and characterization of criticality in two-dimensional (2D)
quantum many-body systems belong to the most important challenges and problems
of quantum physics. In this paper we propose an efficient scheme to solve this
problem by utilizing the infinite projected entangled pair state (iPEPS), and
tensor network (TN) representations. We show that the criticality of a 2D state
is faithfully reproduced by the ground state (dubbed as boundary state) of a
one-dimensional effective Hamiltonian constructed from its iPEPS
representation. We demonstrate that for a critical state the correlation length
and the entanglement spectrum of the boundary state are essentially different
from those of a gapped iPEPS. This provides a solid indicator that allows to
identify the criticality of the 2D state. Our scheme is verified on the
resonating valence bond (RVB) states on kagom\'e and square lattices, where the
boundary state of the honeycomb RVB is found to be described by a $c=1$
conformal field theory. We apply our scheme also to the ground state of the
spin-1/2 XXZ model on honeycomb lattice, illustrating the difficulties of
standard variational TN approaches to study the critical ground states. Our
scheme is of high versatility and flexibility, and can be further applied to
investigate the quantum criticality in many other phenomena, such as
finite-temperature and topological phase transitions.


title: Slowly synchronizing automata with fixed alphabet size

abstract:
  It was conjectured by \v{C}ern\'y in 1964 that a synchronizing DFA on $n$
states always has a shortest synchronizing word of length at most $(n-1)^2$,
and he gave a sequence of DFAs for which this bound is reached.
  In this paper, we investigate the role of the alphabet size. For each
possible alphabet size, we count DFAs on $n \le 6$ states which synchronize in
$(n-1)^2 - e$ steps, for all $e < 2\lceil n/2 \rceil$. Furthermore, we give
constructions of automata with any number of states, and $3$, $4$, or $5$
symbols, which synchronize slowly, namely in $n^2 - 3n + O(1)$ steps.
  In addition, our results prove \v{C}ern\'y's conjecture for $n \le 6$. Our
computation has led to $27$ DFAs on $3$, $4$, $5$ or $6$ states, which
synchronize in $(n-1)^2$ steps, but do not belong to \v{C}ern\'y's sequence. Of
these $27$ DFA's, $19$ are new, and the remaining $8$ which were already known
are exactly the \emph{minimal} ones: they will not synchronize any more after
removing a symbol.
  So the $19$ new DFAs are extensions of automata which were already known,
including the \v{C}ern\'y automaton on $3$ states. But for $n > 3$, we prove
that the \v{C}ern\'y automaton on $n$ states does not admit non-trivial
extensions with the same smallest synchronizing word length $(n-1)^2$.


title:
On the joint distribution of first-passage time and first-passage area
  of drifted Brownian motion

abstract:
  For drifted Brownian motion $X(t)= x - \mu t + B_t \ (\mu >0)$ starting from
$x>0,$ we study the joint distribution of the first-passage time below zero,
$\tau(x),$ and the first-passage area, $A(x),$ swept out by $X$ till the time
$\tau(x).$ In particular, we establish differential equations with boundary
conditions for the joint moments $E[\tau(x)^m A(x)^n],$ and we present an
algorithm to find recursively them, for any $m$ and $n.$ Finally, the expected
value of the time average of $X$ till the time $\tau(x)$ is obtained.


title:
On the applicability of density dependent effective interactions in
  cluster-forming systems

abstract:
  We systematically studied the validity and transferability of effective,
coarse-grained, pair potentials in ultrasoft colloidal systems. We focused on
amphiphilic dendrimers, macromolecules which can aggregate into clusters of
overlapping particles to minimize the contact area with the surrounding
(implicit) solvent. Simulations were performed for both the monomeric and
coarse-grained model in the liquid phase at densities ranging from infinite
dilution up to values close to the freezing point. For every state point, each
macromolecule was mapped onto a single interaction site and the effective pair
potential was computed using a coarse-graining technique based on
force-matching. We found excellent agreement between the spatial dendrimer
distributions obtained from the coarse-grained and microscopically detailed
simulations at low densities, where the macromolecules were distributed
homogeneously in the system. However, the agreement deteriorated significantly
when the density was increased further and the cluster occupation became more
polydisperse. Under these conditions, the effective pair potential of the
coarse-grained model can no longer be computed by averaging over the whole
system, but the local density needs to be taken into account instead.


title: Space-time large deviations in capacity-constrained relay networks

abstract:
  We consider a single-cell network of random transmitters and fixed relays in
a bounded domain of Euclidean space. The transmitters arrive over time and
select one relay according to a spatially inhomogeneous preference kernel. Once
a transmitter is connected to a relay, the connection remains and the relay is
occupied. If an occupied relay is selected by another transmitters with later
arrival time, this transmitter becomes frustrated. We derive a large deviation
principle for the space-time evolution of frustrated transmitters in the
high-density regime.


title:
Carbon and hydrogen radio recombination lines from the cold clouds
  towards Cassiopeia A

abstract:
  We use the Low Frequency Array to perform a systematic high spectral
resolution investigation of the low-frequency 33-78 MHz spectrum along the line
of sight to Cassiopeia A. We complement this with a 304-386 MHz Westerbork
Synthesis Radio telescope observation. In this first paper we focus on the
carbon radio recombination lines.
  We detect Cn$\alpha$ lines at -47 and -38 km s$^{-1}$ in absorption for
quantum numbers n=438-584 and in emission for n=257-278 with high signal to
noise. These lines are associated with cold clouds in the Perseus spiral arm
component. Hn$\alpha$ lines are detected in emission for n=257-278. In
addition, we also detect Cn$\alpha$ lines at 0 km s$^{-1}$ associated with the
Orion arm.
  We analyze the optical depth of these transitions and their line width. Our
models show that the carbon line components in the Perseus arm are best fit
with an electron temperature 85 K and an electron density 0.04 cm$^{-3}$ and
can be constrained to within 15\%. The electron pressure is constrained to
within 20\%. We argue that much of these carbon radio recombination lines arise
in the CO-dark surface layers of molecular clouds where most of the carbon is
ionized but hydrogen has made the transition from atomic to molecular. The
hydrogen lines are clearly associated with the carbon line emitting clouds, but
the low-frequency upperlimits indicate that they likely do not trace the same
gas. Combining the hydrogen and carbon results we arrive at a firm lower limit
to the cosmic ray ionization rate of 2.5$\times$10$^{-18}$ s$^{-1}$, but the
actual value is likely much larger.


title:
Triplet $p$-wave pairing correlation in low doped zigzag graphene
  nanoribbons

abstract:
  We reveal an edge spin triplet $p-$wave superconducting pairing correlation
in slightly doped zigzag graphene nanoribbons. By employing a method that
combines random-phase approximation, the finite-temperature determinant quantum
Monte Carlo approach, and the ground-state constrained-path quantum Monte Carlo
method, it is shown that such a spin-triplet pairing is mediated by the
ferromagnetic fluctuations caused by the flat band at the edge. The spin
susceptibility and effective pairing interactions at the edge strongly increase
as the on-site Coulomb interaction increases, indicating the importance of
electron-electron correlations. It is also found that the doping-dependent
ground-state $p$-wave pairing correlation bears some similarity to the famous
superconducting dome in the phase diagram of a high-temperature superconductor,
while the spin correlation at the edge is weakened as the system is doped away
from half filling.


title:
On the difference between gamma-ray-detected and non-gamma-ray-detected
  pulsars

abstract:
  We compare radio profile widths of young, energetic gamma-ray-detected and
non-gamma-ray-detected pulsars. We find that the latter typically have wider
radio profiles, with the boundary between the two samples exhibiting a
dependence on the rate of rotational energy loss. We also find that within the
sample of gamma-ray-detected pulsars, radio profile width is correlated with
both the separation of the main gamma-ray peaks and the presence of narrow
gamma-ray components. These findings lead us to propose that these pulsars form
a single population where the main factors determining gamma ray detectability
are the rate of rotational energy loss and the proximity of the line of sight
to the rotation axis. The expected magnetic inclination angle distribution will
be different for radio pulsars with and without detectable gamma rays,
naturally leading to the observed differences. Our results also suggest that
the geometry of existing radio and outer-magnetosphere gamma-ray emission
models are at least qualitatively realistic, implying that information about
the viewing geometry can be extracted from profile properties of pulsars.


title:
Equivalence between minimal time and minimal norm control problems for
  the heat equation

abstract:
  This paper presents the equivalence between minimal time and minimal norm
control problems for internally controlled heat equations. The target is an
arbitrarily fixed bounded, closed and convex set with a nonempty interior in
the state space. This study differs from [G. Wang and E. Zuazua, \textit{On the
equivalence of minimal time and minimal norm controls for internally controlled
heat equations}, SIAM J. Control Optim., 50 (2012), pp. 2938-2958] where the
target set is the origin in the state space. When the target set is the origin
or a ball, centered at the origin, the minimal norm and the minimal time
functions are continuous and strictly decreasing, and they are inverses of each
other. However, when the target is located in other place of the state space,
the minimal norm function may be no longer monotonous and the range of the
minimal time function may not be connected. These cause the main difficulty in
our study. We overcome this difficulty by borrowing some idea from the
classical raising sun lemma (see, for instance, Lemma 3.5 and Figure 5 on Pages
121-122 in [E. M. Stein and R. Shakarchi, \textit{Real Analysis: Measure
Theory, Integration, and Hilbert Spaces}, Princeton University Press, 2005]).


title:
How Useful is Region-based Classification of Remote Sensing Images in a
  Deep Learning Framework?

abstract:
  In this paper, we investigate the impact of segmentation algorithms as a
preprocessing step for classification of remote sensing images in a deep
learning framework. Especially, we address the issue of segmenting the image
into regions to be classified using pre-trained deep neural networks as feature
extractors for an SVM-based classifier. An efficient segmentation as a
preprocessing step helps learning by adding a spatially-coherent structure to
the data. Therefore, we compare algorithms producing superpixels with more
traditional remote sensing segmentation algorithms and measure the variation in
terms of classification accuracy. We establish that superpixel algorithms allow
for a better classification accuracy as a homogenous and compact segmentation
favors better generalization of the training samples.


title: Total Order Reliable Convergecast in WBAN

abstract:
  This paper is the first extensive work on total order reliable convergecast
in multi-hop Wireless Body Area Networks (WBAN). Convergecast is a many-to-one
cooperative scheme where each node of the network transmits data towards the
same sink. Our contribution is threefold. First, we stress existing WBAN
convergecast strategies with respect to their capacity to be reliable and to
ensure the total order delivery at sink. That is, packets sent in a specific
order should be received in the same order by the sink. When stressed with
transmission rates up to 500 packets per second the performances of these
strategies decrease dramatically (more than 90% of packets lost). Secondly, we
propose a new posture-centric model for WBAN. This model offers a good
characterization of the path availability which is further used to fine tune
the retransmission rate thresholds. Third, based on our model we propose a new
mechanism for reliability and a new converge-cast strategy that outperforms
WBAN dedicated strategies but also strategies adapted from DTN and WSN areas.
Our extensive performance evaluations use essential parameters for WBAN: packet
lost, total order reliability (messages sent in a specific order should be
delivered in that specific order) and various human body postures. In
particular, our strategy ensures zero packet order inversions for various
transmission rates and mobility postures. Interestingly, our strategy respects
this property without the need of additional energy-guzzler mechanisms.


title: A brief review of E theory

abstract:
  I begin with some memories of Abdus Salam who was my PhD supervisor. After
reviewing the theory of non-linear realisations and Kac-Moody algebras, I
explain how to construct the non-linear realisation based on the Kac-Moody
algebra E11 and its vector representation. I explain how this field theory
leads to dynamical equations which contain an infinite number of fields defined
on a space time with an infinite number of coordinates. I then show that these
unique dynamical equations, when truncated to low level fields and the usual
coordinates of space time, lead to precisely the equations of motion of eleven
dimensional supergravity theory. By taking different group decompositions of
E11 we find all the maximal supergravity theories, including the gauged maximal
supergravities, and as a result the non-linear realisation should be thought of
as a unified theory that is the low energy effective action for type II strings
and branes. These results essentially confirm the E11 conjecture given many
years ago.


title:
A probabilistic network for the diagnosis of acute cardiopulmonary
  diseases

abstract:
  In this paper, the development of a probabilistic network for the diagnosis
of acute cardiopulmonary diseases is presented. This paper is a draft version
of the article published after peer review in 2018
(https://doi.org/10.1002/bimj.201600206). A panel of expert physicians
collaborated to specify the qualitative part, that is a directed acyclic graph
defining a factorization of the joint probability distribution of domain
variables. The quantitative part, that is the set of all conditional
probability distributions defined by each factor, was estimated in the Bayesian
paradigm: we applied a special formal representation, characterized by a low
number of parameters and a parameterization intelligible for physicians,
elicited the joint prior distribution of parameters from medical experts, and
updated it by conditioning on a dataset of hospital patient records using
Markov Chain Monte Carlo simulation. Refinement was cyclically performed until
the probabilistic network provided satisfactory Concordance Index values for a
selection of acute diseases and reasonable inference on six fictitious patient
cases. The probabilistic network can be employed to perform medical diagnosis
on a total of 63 diseases (38 acute and 25 chronic) on the basis of up to 167
patient findings.


title: Orthogonal Series Estimates on Strong Spatial Mixing Data

abstract:
  We study a nonparametric regression model for sample data which is defined on
an $N$-dimensional lattice structure and which is assumed to be strong spatial
mixing: we use design adapted multidimensional Haar wavelets which form an
orthonormal system w.r.t. the empirical measure of the sample data. For such
orthonormal systems, we consider a nonparametric hard thresholding estimator.
We give sufficient criteria for the consistency of this estimator and we derive
rates of convergence. The theorems reveal that our estimator is able to adapt
to the local smoothness of the underlying regression function and the design
distribution. We illustrate our results with simulated examples.


title:
Transparent numerical boundary conditions for evolution equations:
  Derivation and stability analysis

abstract:
  The aim of this article is to propose a systematic study of transparent
boundary conditions for finite difference approximations of evolution
equations. We try to keep the discussion at the highest level of generality in
order to apply the theory to the broadest class of problems. We deal with two
main issues. We first derive transparent numerical boundary conditions, that
is, we exhibit the relations satisfied by the solution to the pure Cauchy
problem when the initial condition vanishes outside of some domain. Our
derivation encompasses discretized transport, diffusion and dispersive
equations with arbitrarily wide stencils. The second issue is to prove sharp
stability estimates for the initial boundary value problem obtained by
enforcing the boundary conditions derived in the first step. We focus here on
discretized transport equations. Under the assumption that the numerical
boundary is non-characteristic, our main result characterizes the class of
numerical schemes for which the corresponding transparent boundary conditions
satisfy the so-called Uniform Kreiss-Lopatinskii Condition introduced in
[GKS72]. Adapting some previous works to the non-local boundary conditions
considered here, our analysis culminates in the derivation of trace and
semigroup estimates for such transparent numerical boundary conditions. Several
examples and possible extensions are given.


title:
Characterizations of projective spaces and quadrics by strictly nef
  bundles

abstract:
  In this paper, we show that if the tangent bundle of a smooth projective
variety is strictly nef, then it is isomorphic to a projective space; if a
projective variety $X^n$ $(n>4)$ has strictly nef $\Lambda^2 TX$, then it is
isomorphic to $\mathbb{P}^n$ or quadric $\mathbb{Q}^n$. We also prove that on
elliptic curves, strictly nef vector bundles are ample, whereas there exist
Hermitian flat and strictly nef vector bundles on any smooth curve with genus
$g\geq 2$.


title:
An Analysis of Technical Debt Management Through Resources Allocation
  Policies in Software Maintenance Process

abstract:
  This paper presents an analysis of technical debt management through
resources allocation policies in software maintenance process during its
operation to demonstrate how different strategies leads to the emergence of
different behaviors along the evolution path. To achieve this objective, this
work used the System Dynamic approach for building a computational simulation
model based on extensive literature review and secondary data. Most of the
works that applied the System Dynamics on software projects research, focused
on initial phases of its life cycle, leaving a gap to be explored regarding the
long-term behaviors of the operation and maintenance phases. The results
demonstrated that the excessive focus on the perfective maintenance activities
could be more costly than performing regular preventive maintenance to reduce
the technical debt incurred, ending up with fewer functionalities deployed,
higher backlog, lower productivity, lower maintainability and higher technical
principal.


title: On the denseness of minimum attaining operators

abstract:
  Let $H_1,H_2$ be complex Hilbert spaces and $T$ be a densely defined closed
linear operator (not necessarily bounded). It is proved that for each
$\epsilon>0$, there exists a bounded operator $S$ with $\|S\|\leq \epsilon$
such that $T+S$ is minimum attaining. Further, if $T$ is bounded below, then
$S$ can be chosen to be rank one.


title:
Distributed Training of Deep Neural Networks: Theoretical and Practical
  Limits of Parallel Scalability

abstract:
  This paper presents a theoretical analysis and practical evaluation of the
main bottlenecks towards a scalable distributed solution for the training of
Deep Neuronal Networks (DNNs). The presented results show, that the current
state of the art approach, using data-parallelized Stochastic Gradient Descent
(SGD), is quickly turning into a vastly communication bound problem. In
addition, we present simple but fixed theoretic constraints, preventing
effective scaling of DNN training beyond only a few dozen nodes. This leads to
poor scalability of DNN training in most practical scenarios.


title:
Interplay between optical, viscous and elastic forces on an optically
  trapped Brownian particle immersed in a viscoelastic fluid

abstract:
  We provide a detailed study of the interplay between the different
interactions which appear in the Brownian motion of a micronsized sphere
immersed in a viscoelastic fluid measured with optical trapping interferometry.
To explore a wide range of viscous, elastic and optical forces, we analyze two
different viscoelastic solutions at various concentrations, which provide a
dynamic polymeric structure surrounding the Brownian sphere. Our experiments
show that, depending of the fluid, optical forces, even if small, slightly
modify the complex modulus at low frequencies. Based on our findings, we
propose an alternative methodology to calibrate this kind of experimental
set-up when non-Newtonian fluids are used. Understanding the influence of the
optical potential is essential for a correct interpretation of the mechanical
properties obtained by optically-trapped probe-based studies of biomaterials
and living matter.


title:
Transformation of the frequency-modulated continuous-wave field into a
  train of short pulses by resonant filters

abstract:
  The resonant filtering method transforming frequency modulated radiation
field into a train of short pulses is proposed to apply in optical domain.
Effective frequency modulation can be achieved by electro-optic modulator or by
resonant frequency modulation of the filter with a narrow absorption line. Due
to frequency modulation narrow-spectrum CW radiation field is seen by the
resonant filter as a comb of equidistant spectral components separated by the
modulation frequency. Tuning narrow-bandwidth filter in resonance with $n$-th
spectral component of the comb transforms the radiation field into bunches of
pulses with $n$ pulses in each bunch. The transformation is explained by the
interference of the coherently scattered resonant component of the field with
the whole comb. Constructive interference results in formation of pulses, while
destructive interference is seen as dark windows between pulses. It is found
that the optimal thickness of the resonant filter is several orders of
magnitude smaller than the necessary thickness of the dispersive filters used
before in optical domain to produce short pulses from the frequency modulated
field.


title:
On a delay differential equation arising from a car-following model:
  Wavefront solutions with constant-speed and their stability

abstract:
  This work is concerned with the study of a scalar delay differential equation
\begin{equation*} z^{\prime\prime}(t)=h^2\,V(z(t-1)-z(t))+h\,z^\prime(t)
\end{equation*} motivated by a simple car-following model on an unbounded
straight line. Here, the positive real $h$ denotes some parameter, and $V$ is a
so-called \textit{optimal velocity function} of the traffic model involved. We
analyze the existence and local stability properties of solutions
$z(t)=c\,t+d$, $t\in\mathbb{R}$, with $c,d\in\mathbb{R}$. In the case
$c\not=0$, such a solution of the differential equation forms a wavefront
solution of the car-following model where all cars are uniformly spaced on the
line and move with the same constant velocity. In particular, it is shown that
all but one of these wavefront solutions are located on two branches
parametrized by $h$. Furthermore, we prove that along the one branch all
solutions are unstable due to the principle of linearized instability, whereas
along the other branch some of the solutions may be stable. The last point is
done by carrying out a center manifold reduction as the linearization does
always have a zero eigenvalue. Finally, we provide some numerical examples
demonstrating the obtained analytical results.


title:
EEG reconstruction and skull conductivity estimation using a Bayesian
  model promoting structured sparsity

abstract:
  M/EEG source localization is an open research issue. To solve it, it is
important to have good knowledge of several physical parameters to build a
reliable head operator. Amongst them, the value of the conductivity of the
human skull has remained controversial. This report introduces a novel
hierarchical Bayesian framework to estimate the skull conductivity jointly with
the brain activity from the M/EEG measurements to improve the reconstruction
quality. A partially collapsed Gibbs sampler is used to draw samples
asymptotically distributed according to the associated posterior. The generated
samples are then used to estimate the brain activity and the model
hyperparameters jointly in a completely unsupervised framework. We use
synthetic and real data to illustrate the improvement of the reconstruction.
The performance of our method is also compared with two optimization algorithms
introduced by Vallagh\'e \textit{et al.} and Gutierrez \textit{et al.}
respectively, showing that our method is able to provide results of similar or
better quality while remaining applicable in a wider array of situations.


title:
Log-convexity and the cycle index polynomials with relation to compound
  Poisson distributions

abstract:
  We extend the exponential formula by Bender and Canfield (1996), which
relates log-concavity and the cycle index polynomials. The extension clarifies
the log-convexity relation. The proof is by noticing the property of a compound
Poisson distribution together with its moment generating function. We also give
a combinatorial proof of extended "log-convex part" referring Bender and
Canfield's approach, where the formula by Bruijn and Erd\"os (1953) is
additionally exploited. The combinatorial approach yields richer structural
results more than log-convexity. Furthermore, we consider normal and binomial
convolutions of sequences which satisfy the exponential formula. The operations
generate interesting examples which are not included in well known laws about
log-concavity/convexity.


title:
Finite frequency Seebeck coefficient of metals: A memory function
  approach

abstract:
  We study the dynamical thermoelectric transport in metals subjected to the
electron-impurity and the electron-phonon interactions using the memory
function formalism. We introduce a generalized Drude form for the Seebeck
coefficient in terms of thermoelectric memory function and calculate the later
in various temperature and frequency limits. In the zero frequency and high
temperature limit, we find that our results are consistent with the
experimental findings and with the traditional Boltzmann equation approach. In
the low temperature limit, we find that the Seebeck coefficient is quadratic in
temperature. In the finite frequency regime, we report new results: In the
electron-phonon interaction case, we find that the Seebeck coefficient shows
frequency independent behavior both in the high frequency regime ($\omega \gg
\omega_{D}$, where $\omega_{D}$ is the Debye frequency) and in the low
frequency regime ($\omega \ll \omega_{D}$), whereas in the intermediate
frequencies, it is a monotonically increasing function of frequency. In the
case of the electron-impurity interaction, first it decays and then after
passing through a minimum it increases with the increase in frequency and
saturates at high frequencies.


title: Comparison of Channels: Criteria for Domination by a Symmetric Channel

abstract:
  This paper studies the basic question of whether a given channel $V$ can be
dominated (in the precise sense of being more noisy) by a $q$-ary symmetric
channel. The concept of "less noisy" relation between channels originated in
network information theory (broadcast channels) and is defined in terms of
mutual information or Kullback-Leibler divergence. We provide an equivalent
characterization in terms of $\chi^2$-divergence. Furthermore, we develop a
simple criterion for domination by a $q$-ary symmetric channel in terms of the
minimum entry of the stochastic matrix defining the channel $V$. The criterion
is strengthened for the special case of additive noise channels over finite
Abelian groups. Finally, it is shown that domination by a symmetric channel
implies (via comparison of Dirichlet forms) a logarithmic Sobolev inequality
for the original channel.


title: Study of Transitions and Decays of Bottomonia at Belle

abstract:
  We review the studies of transitions and decays of bottomonium states from
the e+ e- data recorded by the Belle detector at various Upsilon-resonances. We
also report a recent study of the branching fractions of \chi_{bJ}(1P) to 41
hadronic final states in the Y(2S) data sample. In the same study, a 90%
confidence-level upper limit is set for the first time on the width of
\chi_{b0}(1P) at \Gamma_{total} < 2.4 MeV.


title:
Ambipolar diffusion regulated collapse of filaments threaded by
  perpendicular magnetic fields

abstract:
  We numerically reproduce the density profiles for filaments that are in
magnetohydrostatic and pressure equilibrium with their surroundings obtained in
Tomisaka (2014) and show that these equilibria are dynamically stable. If the
effect of ambipolar diffusion is considered, these filaments lose magnetic
support initiating cloud collapse. The filaments do not lose magnetic flux.
Rather the magnetic flux is redistributed within the filament from the centre
towards the envelope.
  The rate of the collapse is inversely proportional to the fractional
ionisation and two gravitationally-driven ambipolar diffusion regimes for the
collapse are observed as predicted in Mouschovias & Morton (1991). For high
values of the ionisation coefficient, that is $X \geq 10^{-7}$, the gas is
strongly coupled to the magnetic field and the Jeans length is larger than the
ambipolar diffusion length scale. Then the collapse is governed by
magnetically-regulated ambipolar diffusion. For $X \lesssim 10^{-8}$, the gas
is weakly coupled to the magnetic field and the magnetic support is removed by
gravitationally-dominated ambipolar diffusion. Here, neutrals and ions only
collide sporadically, that is the ambipolar diffusion length scale is larger
than the Jeans length.
  When decaying turbulence is included, additional support is provided to the
filament. This slows down the collapse of the filament even in the absence of a
magnetic field. When a magnetic field is present, the collapse rate increases
by a ratio smaller than for the non-magnetic case. This is because of a
speed-up of the ambipolar diffusion due to larger magnetic field gradients
generated by the turbulence and because the ambipolar diffusion aids the
dissipation of turbulence below the ambipolar diffusion length scale. The
highest increase in the rate is observed for the lowest ionisation coefficient
and the highest turbulent intensity.


title:
Consistency and Asymptotic Normality of Stochastic Euler Schemes for
  Ordinary Differential Equations

abstract:
  General stochastic Euler schemes for ordinary differential equations are
studied. We give proofs on the consistency, the rate of convergence and the
asymptotic normality of these procedures.


title: On the cohomology of some exceptional symmetric spaces

abstract:
  This is a survey on the construction of a canonical or "octonionic K\"ahler"
8-form, representing one of the generators of the cohomology of the four
Cayley-Rosenfeld projective planes. The construction, in terms of the
associated even Clifford structures, draws a parallel with that of the
quaternion K\"ahler 4-form. We point out how these notions allow to describe
the primitive Betti numbers with respect to different even Clifford structures,
on most of the exceptional symmetric spaces of compact type.


title: Selective oxidation-induced strengthening of Zr/Nb nanoscale multilayers

abstract:
  The paper presents a new approach, based on controlled oxidation of nanoscale
metallic multilayers, to produce strong and hard oxide/metal nanocomposite
coatings with high strength and good thermal stability. The approach is
demonstrated by performing long term annealing on sputtered Zr/Nb nanoscale
metallic multilayers and investigating the evolution of their microstructure
and mechanical properties by combining analytical transmission electron
microscopy, nano-mechanical tests and finite element models. As-deposited
multilayers were annealed at 350 C in air for times ranging between 1 - 336
hours. The elastic modulus increased by approx. 20% and the hardness by approx.
42% after 15 hours of annealing. Longer annealing times did not lead to changes
in hardness, although the elastic modulus increased up to 35% after 336 hrs.
The hcp Zr layers were rapidly transformed into monoclinic ZrO2 (in the first
15 hours), while the Nb layers were progressively oxidised, from top surface
down towards the substrate, to form an amorphous oxide phase at a much lower
rate. The sequential oxidation of Zr and Nb layers was key for the oxidation to
take place without rupture of the multi-layered structure and without coating
spallation, as the plastic deformation of the metallic Nb layers allowed for
the partial relieve of the residual stresses developed as a result of the
volumetric expansion of the Zr layers upon oxidation. Moreover, the development
of residual stresses induced further changes in mechanical properties in
relation to the annealing time, as revealed by finite element simulations.


title: Damping of nonlinear standing kink oscillations: a numerical study

abstract:
  We aim to study the standing fundamental kink mode of coronal loops in the
nonlinear regime, investigating the changes in energy evolution in the
cross-section and oscillation amplitude of the loop which are related to
nonlinear effects, in particular to the development of the Kelvin-Helmholtz
instability (KHI). We run idea, high-resolution three-dimensional (3D)
magnetohydrodynamics (MHD) simulations, studying the influence of the initial
velocity amplitude and the inhomogeneous layer thickness. We model the coronal
loop as a straight, homogeneous magnetic flux tube with an outer inhomogeneous
layer, embedded in a straight, homogeneous magnetic field. We find that, for
low amplitudes which do not allow for the KHI to develop during the simulated
time, the damping time agrees with the theory of resonant absorption. However,
for higher amplitudes, the presence of KHI around the oscillating loop can
alter the loop's evolution, resulting in a significantly faster damping than
predicted by the linear theory in some cases. This questions the accuracy of
seismological methods applied to observed damping profiles, based on linear
theory.


title:
Focusing characteristics of a 4$\pi$ parabolic mirror light-matter
  interface

abstract:
  Focusing with a 4$\pi$ parabolic mirror allows for concentrating light from
nearly the complete solid angle, whereas focusing with a single microscope
objective limits the angle cone used for focusing to half solid angle at
maximum. Increasing the solid angle by using deep parabolic mirrors comes at
the cost of adding more complexity to the mirror's fabrication process and
might introduce errors that reduce the focusing quality. To determine these
errors, we experimentally examine the focusing properties of a 4$\pi$ parabolic
mirror that was produced by single-point diamond turning. The properties are
characterized with a single $^{174}$Yb$^{+}$ ion as a mobile point scatterer.
The ion is trapped in a vacuum environment with a movable high optical access
Paul trap. We demonstrate an effective focal spot size of 209 nm in lateral and
551 nm in axial direction. Such tight focusing allows us to build an efficient
light-matter interface. Our findings agree with numerical simulations
incorporating a finite ion temperature and interferometrically measured
wavefront aberrations induced by the parabolic mirror. We point at further
technological improvements and discuss the general scope of applications of a
4$\pi$ parabolic mirror.


title:
Experimental and theoretical analyses of strongly polarized photon
  emission from non-polar InGaN quantum dots

abstract:
  We present a comprehensive investigation of the polarization properties of
non-polar a-plane InGaN quantum dots (QDs) and their origin with statistically
significant experimental data and rigorous k.p modelling. The unbiased
selection and study of 180 individual QDs allow us to compute an average
polarization degree of 0.90, with a standard deviation of only 0.08. When
coupled with theoretical insights, we show that a-plane InGaN QDs are highly
insensitive to size differences, shape anisotropies, and indium content
fluctuations. Furthermore, 91% of the studied QDs exhibit a polarization axis
along the crystal [1-100] axis, with the other 9% polarized orthogonal to this
direction. When coupled with their ability to emit single-photons, a-plane QDs
are good candidates for the generation of linearly polarized single-photons, a
feature attractive for quantum cryptography protocols.


title: Doubly heavy baryon spectra guided by lattice QCD

abstract:
  This paper provides results for the ground state and excited spectra of
three-flavored doubly heavy baryons, $bcn$ and $bcs$. We take advantage of the
spin-independent interaction recently obtained to reconcile the lattice SU(3)
QCD static potential and the results of nonperturbative lattice QCD for the
triply heavy baryon spectra. We show that the spin-dependent potential might be
constrained on the basis of nonperturbative lattice QCD results for the spin
splittings of three-flavored doubly heavy baryons. Our results may also
represent a challenge for future lattice QCD work, because a smaller lattice
error could help in distinguishing between different prescriptions for the
spin-dependent part of the interaction. Thus, by comparing with the reported
baryon spectra obtained with parameters estimated from lattice QCD, one can
challenge the precision of lattice calculations. The present work supports a
coherent description of singly, doubly and triply heavy baryons with the same
Cornell-like interacting potential. The possible experimental measurement of
these states at LHCb is an incentive for this study.


title: Darkflation -- one scalar to rule them all?

abstract:
  The problem of explaining both inflationary and dark matter physics in the
framework of a minimal extension of the Standard Model was investigated. To
this end, the Standard Model completed by a real scalar singlet playing a role
of the dark matter candidate has been considered. We assumed both the dark
matter field and the Higgs doublet to be nonminimally coupled to gravity. Using
quantum field theory in curved spacetime we derived an effective action for the
inflationary period and analyzed its consequences. In this approach, after
integrating out both dark matter and Standard Model sectors we obtained the
effective action expressed purely in terms of the gravitational field. We paid
special attention to determination, by explicit calculations, of the form of
coefficients controlling the higher-order in curvature gravitational terms.
Their connection to the Standard Model coupling constants has been discussed.


title: Analysis of Network Robustness for Finite Sized Wireless Sensor Networks

abstract:
  Studying network robustness for wireless sensor networks(WSNs) is an exciting
topic of research as sensor nodes often fail due to hardware degradation,
resource constraints, and environmental changes. The application of spectral
graph theory to networked systems has generated several important results.
However, previous research has often failed to consider the network parameters,
which is crucial to study the real network applications. Network criticality is
one of the effective metrics to quantify the network robustness against such
failures and attacks. In this work, we derive the exact formulas of network
criticality for WSNs using r-nearest neighbor networks and we show the effect
of nearest neighbors and network dimension on robustness using analytical and
numerical evaluations. Furthermore, we also show how symmetric and static
approximations can wrongly designate the network robustness when implemented to
WSNs.


title:
Charmonium production in Pb-Pb collisions at $\sqrt{s_{\rm NN}} =$ 2.76
  and 5.02 TeV with ALICE

abstract:
  The production of charmonium states, J/$\psi$ and $\psi$(2S), in heavy-ion
collisions, is an important probe to investigate the formation of a plasma of
quarks and gluons (QGP). In a hot and deconfined medium, quarkonium production
is, indeed, expected to be significantly modified, with respect to the pp
yields, due to a balance of color screening and charm-quark recombination
mechanisms. The ALICE Collaboration at the LHC has measured charmonium
production in Pb-Pb collisions at $\sqrt{s}_{\rm NN} =$ 2.76 and 5.02 TeV. The
nuclear modification factor of inclusive J/$\psi$, evaluated at forward
($-4<\eta<-2.5$) rapidity, is measured as a function of the centrality of the
collision and of the J/$\psi$ kinematic variables as transverse momentum and
rapidity. In this article, we report on the new J/$\psi$ results, obtained at
forward rapidity, at $\sqrt{s}_{\rm NN} = 5.02$ TeV. These new results are
compared to the J/$\psi$ nuclear modification factor obtained at $\sqrt{s}_{\rm
NN} =$ 2.76 TeV and to the available theoretical predictions.


title:
Scaling and interaction of self-similar modes in models of high-Reynolds
  number wall turbulence

abstract:
  Previous work has established the usefulness of the resolvent operator that
maps the terms nonlinear in the turbulent fluctuations to the fluctuations
themselves. Further work has described the self-similarity of the resolvent
arising from that of the mean velocity profile. The orthogonal modes provided
by the resolvent analysis describe the wall-normal coherence of the motions and
inherit that self-similarity. In this contribution, we present the implications
of this similarity for the nonlinear interaction between modes with different
scales and wall-normal locations. By considering the nonlinear interactions
between modes, it is shown that much of the turbulence scaling behaviour in the
logarithmic region can be determined from a single arbitrarily chosen reference
plane. Thus, the geometric scaling of the modes is impressed upon the nonlinear
interaction between modes. Implications of these observations on the
self-sustaining mechanisms of wall turbulence, modelling and simulation are
outlined.


title: Modified dispersion relations, inflation and scale invariance

abstract:
  For a certain type of modified dispersion relations, the vacuum quantum state
for very short wavelength cosmological perturbations is scale-invariant and it
has been suggested that this may be the source of the scale-invariance observed
in the temperature anisotropies in the cosmic microwave background. We point
out that for this scenario to be possible, it is necessary to redshift these
short wavelength modes to cosmological scales in such a way that the
scale-invariance is not lost. This requires non-trivial background dynamics
before the onset of standard radiation-dominated cosmology; we demonstrate that
one possible solution is inflation with a sufficiently large Hubble rate, for
this slow roll is not necessary. In addition, we also show that if the
slow-roll condition is added to inflation with a large Hubble rate, then for
any power law modified dispersion relation quantum vacuum fluctuations become
nearly scale-invariant when they exit the Hubble radius.


title:
A Low Order Finite Element Method for Poroelasticity with Applications
  to Lung Modelling

abstract:
  In this thesis we develop a stabilised finite element method for solving the
equations of poroelasticity to enable solving complex models of biological
tissues such as the human lungs. For the proposed numerical scheme, we use the
lowest possible approximation order: piecewise constant approximation for the
pressure, and piecewise linear continuous elements for the displacements and
fluid flux. Due to the discontinuous pressure approximation, sharp pressure
gradients due to changes in material coefficients or boundary layer solutions
can be captured reliably. We begin by developing theoretical results for
approximating the linear poroelastic equations valid in small deformations. In
particular, we prove existence and uniqueness, an energy estimate and an
optimal a-priori error estimate for the discretised problem. We then extend
this work and construct a stabilised finite element method to solve the
poroelastic equations valid in large deformations. We present the linearisation
and discretisation for this nonlinear problem, and give a detailed account of
the implementation. We rigorously test both the linear and nonlinear finite
element method using numerous test problems to verify theoretical stability and
convergence results, and the method's ability to reliably capture steep
pressure gradients. Finally, we derive a poroelastic model for lung parenchyma
coupled to an airway fluid network model, and develop a stable method to solve
the coupled model. Numerical simulations, on a realistic lung geometry,
illustrate the coupling between the poroelastic medium and the network flow
model, and simulations of tidal breathing are shown to reproduce global
physiologically realistic measurements. We also investigate the effect of
airway constriction and tissue weakening on the ventilation, tissue stress and
alveolar pressure distribution.


title:
Centralizers of irreducible subgroups in the projective special linear
  group

abstract:
  In this paper, we classify conjugacy classes of centralizers of irreducible
subgroups in $PSL(n,\mathbb{C})$ using alternate modules a.k.a. finite abelian
groups with an alternate bilinear form. When $n$ is squarefree, we prove that
these conjugacy classes are classified by their isomorphism classes. More
generally, we define a finite graph related to this classification whose
combinatorial properties are expected to help us describe the stratification of
the singular (orbifold) locus in some character varieties.


title:
Adsorption-induced symmetry reduction of metal-phthalocyanines studied
  by vibrational spectroscopy

abstract:
  We investigate the vibrational properties of Pt- and Pd-phthalocyanine (PtPc
and PdPc) molecules on Ag(111) with high resolution electron energy loss
spectroscopy (HREELS). In the monolayer regime, both molecules exhibit long
range order. The vibrational spectra prove a flat adsorption geometry. The red
shift of vibrational modes and the presence of asymmetric vibrational peaks
suggest a moderate interaction of the molecules with the substrate, accompanied
by a static charge transfer from the metal to the molecules. The appearance of
a particular vibrational mode, which (i) belongs to the $\mathrm{B_{1g}}$
representation of the original fourfold $\mathrm{D_{4h}}$ molecular symmetry
group and which (ii) exhibits interfacial dynamical charge transfer (IDCT),
proves that a preferential charge transfer from the Ag surface into one of the
originally doubly degenerate lowest unoccupied molecular orbitals (LUMOs) of
$\mathrm{E_g}$ symmetry takes place, i.e. the electronic degeneracy is lifted
and the molecule-surface complex acquires the twofold symmetry group
$\mathrm{C_{2v}}$. The vibration-based analysis of orbital degeneracies, as
carried out here for PtPc/Ag(111) and PdPc/Ag(111), is not restricted to these
cases. It is particularly useful whenever the presence of multiple molecular
in-plane orientations at the interface makes the analysis of orbital
degeneracies with angle-resolved photoemission spectroscopy difficult.


title:
Short proofs for $q$-Raabe formula and integrals for Jacobi theta
  functions

abstract:
  We shall answer a question of Mez\H{o} on the $q$-analogue of the Raabe's
integral formula for $0<q<1$ and we shall evaluate an integral involving the
first theta function. Moreover, we will reproduce short proofs for some
identities of Mez\H{o}.


title:
Realtime Hierarchical Clustering based on Boundary and Surface
  Statistics

abstract:
  Visual grouping is a key mechanism in human scene perception. There, it
belongs to the subconscious, early processing and is key prerequisite for other
high level tasks such as recognition. In this paper, we introduce an efficient,
realtime capable algorithm which likewise agglomerates a valuable hierarchical
clustering of a scene, while using purely local appearance statistics. To speed
up the processing, first we subdivide the image into meaningful, atomic
segments using a fast Watershed transform. Starting from there, our rapid,
agglomerative clustering algorithm prunes and maintains the connectivity graph
between clusters to contain only such pairs, which directly touch in the image
domain and are reciprocal nearest neighbors (RNN) wrt. a distance metric. The
core of this approach is our novel cluster distance: it combines boundary and
surface statistics both in terms of appearance as well as spatial linkage. This
yields state-of-the-art performance, as we demonstrate in conclusive
experiments conducted on BSDS500 and Pascal-Context datasets.


title: Entropy production in nonlinear recombination models

abstract:
  We study the convergence to equilibrium of a class of nonlinear recombination
models. In analogy with Boltzmann's H theorem from kinetic theory, and in
contrast with previous analysis of these models, convergence is measured in
terms of relative entropy. The problem is formulated within a general framework
that we refer to as Reversible Quadratic Systems. Our main result is a tight
quantitative estimate for the entropy production functional. Along the way we
establish some new entropy inequalities generalizing Shearer's and related
inequalities.


title: Studies of correlations between measurements of jet observables

abstract:
  We present a method for calculation of statistical correlations between
measured jet observables in high energy collisions. The method is compared to
sampling based methods used in the past. The case of measurements of jet rates
in $e^+e^-$ collisions is considered in detail.


title: Magnetization oscillations and waves driven by pure spin currents

abstract:
  Recent advances in the studies of pure spin currents - flows of angular
momentum (spin) not accompanied by the electric currents - have opened new
horizons for the emerging technologies based on the electron's spin degree of
freedom, such as spintronics and magnonics. The main advantage of pure spin
current, as compared to the spin-polarized electric current, is the possibility
to exert spin transfer torque on the magnetization in thin magnetic films
without electrical current flow through the material. In addition to minimizing
Joule heating and electromigration effects, this characteristic enables the
implementation of spin torque devices based on the low-loss insulating magnetic
materials, and offers an unprecedented geometric flexibility. Here we review
the recent experimental achievements in investigations of magnetization
oscillations excited by pure spin currents in different magnetic nanosystems
based on metallic and insulating magnetic materials. We discuss the spectral
properties of spin-current nano-oscillators, and relate them to the spatial
characteristics of the excited dynamic magnetic modes determined by the
spatially-resolved measurements. We also show that these systems support
locking of the oscillations to external microwave signals, as well as their
mutual synchronization, and can be used as efficient nanoscale sources of
propagating spin waves.


title: Strangeness production in p-Pb and Pb-Pb collisions with ALICE at LHC

abstract:
  The main goal of the ALICE experiment is to study the properties of the hot
and dense medium created in ultra-relativistic heavy-ion collisions. The
measurement of the (multi-)strange particles is an important tool to understand
particle production mechanisms and the dynamics of the quark-gluon plasma
(QGP). We report on the production of K$^{0}_{S}$,
$\Lambda$($\overline{\Lambda}$), $\Xi^{-}$($\overline{\Xi}^{+}$) and
$\Omega^{-}$($\overline{\Omega}^{+}$) in proton-lead (p-Pb) collisions at
$\sqrt{s_{\rm NN}}$ = 5.02 TeV and lead-lead (Pb-Pb) collisions at
$\sqrt{s_{\rm NN}}$ = 2.76 TeV measured by ALICE at the LHC. The comparison of
the hyperon-to-pion ratios in the two colliding systems may provide insight
into strangeness production mechanisms, while the comparison of the nuclear
modification factors helps to determine the contribution of initial state
effects and the suppression from strange quark energy loss in nuclear matter.


title: On growth of metabelian Lie algebras

abstract:
  For any integer $d\geq 1$ we construct examples of finitely presented
algebras with intermediate growth of type $[e^{n^{d/(d+1)}}]$. We produce these
examples by computing the growth types of some finitely presented metabelian
Lie algebras.


title: Patching and the p-adic Langlands program for GL(2, Q_p)

abstract:
  We present a new construction of the p-adic local Langlands correspondence
for GL(2, Q_p) via the patching method of Taylor--Wiles and Kisin. This
construction sheds light on the relationship between the various other
approaches to both the local and global aspects of the p-adic Langlands
program; in particular, it gives a new proof of many cases of the second
author's local-global compatibility theorem, and relaxes a hypothesis on the
local mod p representation in that theorem.


title: The universal rotation curve of dwarf disk galaxies

abstract:
  We use the concept of the spiral rotation curves universality to investigate
the luminous and dark matter properties of the dwarf disc galaxies in the local
volume (size $\sim11$ Mpc). Our sample includes 36 objects with rotation curves
carefully selected from the literature. We find that, despite the large
variations of our sample in luminosities ($\sim$ 2 of dex), the rotation curves
in specifically normalized units, look all alike and lead to the lower-mass
version of the universal rotation curve of spiral galaxies found in Persic et
al. We mass model the double normalized universal rotation curve
$V(R/R_{opt})/V_{opt}$ of dwarf disc galaxies: the results show that these
systems are totally dominated by dark matter whose density shows a core size
between 2 and 3 stellar disc scale lengths. Similar to galaxies of different
Hubble types and luminosities, the core radius $r_0$ and the central density
$\rho_0$ of the dark matter halo of these objects are related by $ \rho_0 r_0
\sim 100\hspace{0.1cm} \mathrm{M_\odot pc^{-2}}$. The structural properties of
the dark and luminous matter emerge very well correlated. In addition, to
describe these relations, we need to introduce a new parameter, measuring the
compactness of light distribution of a (dwarf) disc galaxy. These structural
properties also indicate that there is no evidence of abrupt decline at the
faint end of the baryonic to halo mass relation. Finally, we find that the
distributions of the stellar disc and its dark matter halo are closely related.


title:
Measurement of the $^{20-22}$Ne $^3$P$_2$-$^3$D$_3$ transition isotope
  shift using a single, phase modulated laser beam

abstract:
  We develop a simple technique to accurately measure frequency differences
between far lying resonances in a spectroscopy signal using a single laser.
This technique was used to measure the isotope shift of the cooling transition
of metastable neon for the result of $1626.264(79)$ MHz. The most accurate
determination of this value to date.


title:
Chemical potential of a test hard sphere of variable size in a
  hard-sphere fluid

abstract:
  The Lab\'ik and Smith Monte Carlo simulation technique to implement the Widom
particle insertion method is applied using Molecular Dynamics (MD) instead to
calculate numerically the insertion probability, $P_0(\eta,\sigma_0)$, of
tracer hard-sphere (HS) particles of different diameters, $\sigma_0$, in a host
HS fluid of diameter $\sigma$ and packing fraction, $\eta$, up to $0.5$. It is
shown analytically that the only polynomial representation of $-\ln
P_0(\eta,\sigma_0)$ consistent with the limits $\sigma_0\to 0$ and
$\sigma_0\to\infty$ has necessarily a cubic form,
$c_0(\eta)+c_1(\eta)\sigma_0/\sigma+c_2(\eta)(\sigma_0/\sigma)^2+c_3(\eta)(\sigma_0/\sigma)^3$.
Our MD data for $-\ln P_0(\eta,\sigma_0)$ are fitted to such a cubic polynomial
and the functions $c_0(\eta)$ and $c_1(\eta)$ are found to be statistically
indistinguishable from their exact solution forms. Similarly, $c_2(\eta)$ and
$c_3(\eta)$ agree very well with the
Boubl\'ik-Mansoori-Carnahan-Starling-Leland and
Boubl\'ik-Carnahan-Starling-Kolafa formulas. The cubic polynomial is
extrapolated (high density) or interpolated (low density) to obtain the
chemical potential of the host fluid, or $\sigma_{0}\to\sigma$, as
$\beta\mu^{\text{ex}}=c_0+c_1+c_2+c_3$. Excellent agreement between the
Carnahan-Starling and Carnahan-Starling-Kolafa theories with our MD data is
evident.


title:
On a Question of Bouras concerning weak compactness of almost
  Dunford-Pettis sets

abstract:
  We give a positive answer to the question of K. Bouras [`Almost
Dunford-Pettis sets in Banach lattices', \textit{Rend. Circ. Mat. Palermo (2)}
\textbf{ 62} (2013), 227--236] concerning weak compactness of almost
Dunford-Pettis sets in Banach lattices. That is, every almost Dunford-Pettis
set in a Banach lattice $E$ is relatively weakly compact if, and only if, $E$
is a $KB$-space.


title:
Discrete approximation of the minimizing movement scheme for evolution
  equations of Wasserstein gradient flow type with nonlinear mobility

abstract:
  We propose a fully discrete variational scheme for nonlinear evolution
equations with gradient flow structure on the space of finite Radon measures on
an interval with respect to a generalized version of the Wasserstein distance
with nonlinear mobility. Our scheme relies on a spatially discrete
approximation of the semi-discrete (in time) minimizing movement scheme for
gradient flows. Performing a finite-volume discretization of the continuity
equation appearing in the definition of the distance, we obtain a
finite-dimensional convex minimization problem usable as an iterative scheme.
We prove that solutions to the spatially discrete minimization problem converge
to solutions of the spatially continuous original minimizing movement scheme
using the theory of $\Gamma$-convergence, and hence obtain convergence to a
weak solution of the evolution equation in the continuous-time limit if the
minimizing movement scheme converges. We illustrate our result with numerical
simulations for several second- and fourth-order equations.


title: Nice Restrictions of Reflection Arrangements

abstract:
  In a recent paper, Hoge and the second author classified all nice and all
inductively factored reflection arrangements. In this note we extend this
classification by determining all nice and all inductively factored
restrictions of reflection arrangements.


title:
The Surface Roughness of (433) Eros as Measured by Thermal-Infrared
  Beaming

abstract:
  In planetary science, surface roughness is regarded to be a measure of
surface irregularity at small spatial scales, and causes the thermal-infrared
beaming effect (i.e. re-radiation of absorbed sunlight back towards to the
Sun). Typically, surface roughness exhibits a degeneracy with thermal inertia
when thermophysical models are fitted to disc-integrated thermal-infrared
observations of asteroids because of this effect. In this work, it is
demonstrated how surface roughness can be constrained for near-Earth asteroid
(433) Eros (i.e. the target of NASA's NEAR Shoemaker mission) when using the
Advanced Thermophysical Model with thermal-infrared observations taken during
an "almost pole-on" illumination and viewing geometry. It is found that the
surface roughness of (433) Eros is characterised by an RMS slope of 38 $\pm$
8{\deg} at the 0.5-cm spatial scale associated with its thermal-infrared
beaming effect. This is slightly greater than the RMS slope of 25 $\pm$ 5{\deg}
implied by the NEAR Shoemaker laser ranging results when extrapolated to this
spatial scale, and indicates that other surface shaping processes might
operate, in addition to collisions and gravity, at spatial scales under one
metre in order to make asteroid surfaces rougher. For other high obliquity
asteroids observed during "pole-on" illumination conditions, the
thermal-infrared beaming effect allows surface roughness to be constrained when
the sub-solar latitude is greater than 60{\deg}, and if the asteroids are
observed at phase angles of less than 40{\deg}. They will likely exhibit NEATM
beaming parameters that are lower than expected for a typical asteroid at all
phase angles up to 100{\deg}.


title: Off-shell massive N=1 supermultiplets in three dimensions

abstract:
  This paper is mainly concerned with the construction of new off-shell higher
spin N=1 supermultiplets in three spacetime dimensions. We elaborate on the
gauge prepotentials and linearised super-Cotton tensors for higher spin N=1
superconformal geometry and propose compensating superfields required to
formulate off-shell massless higher spin supermultiplets. The corresponding
gauge-invariant actions are worked out explicitly using an auxiliary oscillator
realisation. We construct, for the first time, off-shell massive higher spin
supermultiplets. The gauge-invariant actions for these supermultiplets are
obtained by adding Chern-Simons like mass terms (that is, higher spin
extensions of the linearised action for N=1 conformal supergravity) to the
actions for the massless supermultiplets. For each of the massive gravitino and
supergravity multiplets, we propose two dually equivalent formulations.


title:
On the Wiener index, distance cospectrality and transmission regular
  graphs

abstract:
  In this paper, we investigate various algebraic and graph theoretic
properties of the distance matrix of a graph. Two graphs are $D$-cospectral if
their distance matrices have the same spectrum. We construct infinite pairs of
$D$-cospectral graphs with different diameter and different Wiener index. A
graph is $k$-transmission-regular if its distance matrix has constant row sum
equal to $k$. We establish tight upper and lower bounds for the row sum of a
$k$-transmission-regular graph in terms of the number of vertices of the graph.
Finally, we determine the Wiener index and its complexity for linear $k$-trees,
and obtain a closed form for the Wiener index of block-clique graphs in terms
of the Laplacian eigenvalues of the graph. The latter leads to a generalization
of a result for trees which was proved independently by Mohar and Merris.


title:
Critical behaviour of ($2+1$)-dimensional QED: $1/N_f$-corrections in an
  arbitrary non-local gauge

abstract:
  Dynamical chiral symmetry breaking (D$\chi$SB) is studied within
($2+1$)-dimensional QED with $N$ four-component fermions. The leading and
next-to-leading orders of the $1/N$ expansion are computed exactly. The
analysis is carried out in an arbitrary non-local gauge. Resumming the
wave-function renormalization constant at the level of the gap equation yields
a strong suppression of the gauge dependence of the critical fermion flavour
number, $N_c(\xi)$ where $\xi$ is the gauge fixing parameter, which is such
that D$\chi$SB takes place for $N<N_c(\xi)$. Neglecting the weak
gauge-dependent terms yields $N_c = 2.8469$ while, in the general case, it is
found that: $N_c(1) = 3.0084$ in the Feynman gauge, $N_c(0) = 3.0844$ in the
Landau gauge and $N_c(2/3)= 3.0377$ in the $\xi=2/3$ gauge where the leading
order fermion wave function is finite. These results suggest that D$\chi$SB
should take place for integer values $N \leq 3$.


title: Two-sided multiplication operators on the space of regular operators

abstract:
  Let $W$, $X$, $Y$ and $Z$ be Dedekind complete Riesz spaces. For $A\in
L^{r}(Y, Z)$ and $B\in L^{r}(W, X)$ let $M_{A,\,B}$ be the two-sided
multiplication operator from $L^{r}(X, Y)$ into $L^r(W,\,Z)$ defined by
$M_{A,\,B}(T)=ATB$. We show that for every $0\leq A_0\in L^{r}_{n}(Y, Z)$,
$|M_{A_0, B}|(T)=M_{A_0, |B|}(T)$ holds for all $B\in L^{r}(W, X)$ and all
$T\in L^{r}_{n}(X, Y)$. Furthermore, if $W$, $X$, $Y$ and $Z$ are Dedekind
complete Banach lattices such that $X$ and $Y$ have order continuous norms,
then $|M_{A,\, B}|=M_{|A|, \,|B|}$ for all $ A\in L^{r}(Y, Z)$ and all $B\in
L^{r}(W, X)$. Our results generalize the related results of Synnatzschke and
Wickstead, respectively.


title:
The role of pebble fragmentation in planetesimal formation I.
  Experimental study

abstract:
  Previous work on protoplanetary dust growth shows halt at centimeter sizes
owing to the occurrence of bouncing at velocities of $\geq$ 0.1 $ms^{-1}$ and
fragmentation at velocities $\geq$ 1 $ms^{-1}$. To overcome these barriers,
spatial concentration of cm-sized dust pebbles and subsequent gravitational
collapse have been proposed. However, numerical investigations have shown that
dust aggregates may undergo fragmentation during the gravitational collapse
phase. This fragmentation in turn changes the size distribution of the solids
and thus must be taken into account in order to understand the properties of
the planetesimals that form. To explore the fate of dust pebbles undergoing
fragmenting collisions, we conducted laboratory experiments on dust-aggregate
collisions with a focus on establishing a collision model for this stage of
planetesimal formation. In our experiments, we analysed collisions of dust
aggregates with masses between 1.4 g and 180 g, mass ratios between target and
projectile from 125 to 1 at a fixed porosity of 65%, within the velocity range
of 1.5 $-$ 8.7 $ms^{-1}$ , at low atmospheric pressure of $\sim 10^{-3}$ mbar
and in free-fall conditions. We derived the mass of the largest fragment, the
fragment size/mass distribution, and the efficiency of mass transfer as a
function of collision velocity and projectile/target aggregate size. Moreover,
we give recipes for an easy-to-use fragmentation and mass-transfer model for
further use in modeling work. In a companion paper, we utilize the experimental
findings and the derived dust-aggregate collision model to investigate the fate
of dust pebbles during gravitational collapse.


title:
Quintessential Inflation, Unified Dark Energy and Dark Matter, and Higgs
  Mechanism

abstract:
  We describe a new type of gravity-matter models where gravity couples in a
non-conventional way to two distinct scalar fields providing a unified
Lagrangian action principle description of: (a) the evolution of both "early"
and "late" Universe - by the "inflaton" scalar field; (b) dark energy and dark
matter as a unified manifestation of a single material entity - the "darkon"
scalar field. The essential non-standard feature of our models is employing the
formalism of non-Riemannian space-time volume forms - alternative generally
covariant integration measure densities (volume elements) defined in terms of
auxiliary antisymmetric tensor gauge fields. Although being (almost) pure-gauge
degrees of freedom, the non-Riemannian space-time volume forms trigger a series
of important features unavailable in ordinary gravity-matter models. When
including in addition interactions with the electro-weak model bosonic sector
we obtain a gravity-assisted generation of electro-weak spontaneous gauge
symmetry breaking in the post-inflationary "late" Universe, while the
Higgs-like scalar remains massless in the "early" Universe.


title: Topological Gapless Phases in Non-Symmorphic Antiferromagnets

abstract:
  Topologically protected fermionic quasiparticles occur in metals with band
degeneracy as a consequence of band structure topology. Here we unveil
topological semimetal and metal phases in a variety of non-symmorphic collinear
antiferromagnets with glide reflection symmetry, a combination of mirror and
half-lattice translation. We find gapless phases with Dirac points having
multiple symmetry-protection as well as electronic structures with triple and
quadruple band-crossing points. Glide semimetal is shown to be converted into a
topological phase with non-trivial $\mathbb{Z}_2$ topological charges at the
Dirac points due to inversion and time-inversion symmetry combination. More
striking is the emergence of a hidden non-unitary relation between the states
in the glide sectors that provide a general mechanism to get multiple band
touching points. The split Fermi points uncover a $\mathbb{Z}_2$ protection
that drives the changeover of the multiple-degenerate gapless phase into a
topological metal built from their connection through distinct Fermi lines.
Besides a new perspective of ordered states in complex materials, our findings
indicate that novel topological gapless phases and edge states may occur in a
wide class of magnetic systems.


title: Optimal Deterministic Algorithm Generation

abstract:
  A formulation for the automated generation of algorithms via mathematical
programming (optimization) is proposed. The formulation is based on the concept
of optimizing within a parameterized family of algorithms, or equivalently a
family of functions describing the algorithmic steps. The optimization
variables are the parameters -within this family of algorithms- that encode
algorithm design: the computational steps of which the selected algorithms
consists. The objective function of the optimization problem encodes the merit
function of the algorithm, e.g., the computational cost (possibly also
including a cost component for memory requirements) of the algorithm execution.
The constraints of the optimization problem ensure convergence of the
algorithm, i.e., solution of the problem at hand. The formulation is described
prototypically for algorithms used in solving nonlinear equations and in
performing unconstrained optimization; the parametrized algorithm family
considered is that of monomials in function and derivative evaluation
(including negative powers). A prototype implementation in GAMS is developed
along with illustrative results demonstrating cases for which well-known
algorithms are shown to be optimal. The formulation is a mixed-integer
nonlinear program (MINLP). To overcome the multimodality arising from
nonconvexity in the optimization problem, a combination of brute force and
general-purpose deterministic global algorithms is employed to guarantee the
optimality of the algorithm devised. We then discuss several directions towards
which this methodology can be extended, their scope and limitations.


title:
Compact K$\"a$hler manifolds homotopic to negatively curved Riemannian
  manifolds

abstract:
  In this paper, we show that any compact K$\"a$hler manifold homotopic to a
compact Riemannian manifold with negative sectional curvature admits a
K$\"a$hler-Einstein metric of general type. Moreover, we prove that, on a
compact symplectic manifold $X$ homotopic to a compact Riemannian manifold with
negative sectional curvature, for any almost complex structure $J$ compatible
with the symplectic form, there is no non-constant $J$-holomorphic entire curve
$f:C \rightarrow X$.


title: A $K_s$-band selected catalogue of objects in the ALHAMBRA survey

abstract:
  The original ALHAMBRA catalogue contained over 400,000 galaxies selected
using a synthetic F814W image, to the magnitude limit AB(F814W)$\approx$24.5.
Given the photometric redshift depth of the ALHAMBRA multiband data (<z>=0.86)
and the approximately $I$-band selection, there is a noticeable bias against
red objects at moderate redshift. We avoid this bias by creating a new
catalogue selected in the $K_s$ band. This newly obtained catalogue is
certainly shallower in terms of apparent magnitude, but deeper in terms of
redshift, with a significant population of red objects at $z>1$. We select
objects using the $K_s$ band images, which reach an approximate AB magnitude
limit $K_s \approx 22$. We generate masks and derive completeness functions to
characterize the sample. We have tested the quality of the photometry and
photometric redshifts using both internal and external checks. Our final
catalogue includes $\approx 95,000$ sources down to $K_s \approx 22$, with a
significant tail towards high redshift. We have checked that there is a large
sample of objects with spectral energy distributions that correspond to that of
massive, passively evolving galaxies at $z > 1$, reaching as far as $z \approx
2.5$. We have tested the possibility of combining our data with deep infrared
observations at longer wavelengths, particularly Spitzer IRAC data.


title:
Dark Energy and Dark Matter in a Model of an Axion Coupled to a
  Non-Abelian Gauge Field

abstract:
  We study cosmological field configurations (solutions) in a model in which
the pseudo-scalar phase of a complex field couples to the Pontryagin density of
a massive non-abelian gauge field, in analogy to how the Peccei-Quinn axion
field couples to the $SU(3)$-color gauge field of QCD. Assuming that the
self-interaction potential of the complex scalar field has the typical {\it
Mexican hat} form, we find that the radial fluctuations of this field can act
as {\it Dark Matter}, while its phase may give rise to tracking {\it Dark
Energy}. In our model, Dark-Energy domination will, however, not continue for
ever. A new component of dark matter, namely the one originating from the gauge
field, will dominate in the future.


title:
Inductive limits of finite dimensional hermitian symmetric spaces and
  K-theory

abstract:
  K-Theory for hermitian symmetric spaces of non-compact type, as developed
recently by the authors, allows to put Cartan's classification into a
homological perspective. We apply this method to the case of inductive limits
of finite dimensional hermitian symmetric spaces. This might be seen as an
indication of how much more powerful the homological theory is in comparison to
the more classical approach.
  When seen from high above, we follow the path laid out by a similar result in
the theory of C*-algebras. Important is a clear picture of the behavior of
morphisms between bounded symmetric domains of finite dimensions, which is more
complex than in the C*-case, as well as an accessible K-theory. We furthermore
have to slightly modify the invariant from our previous work. Roughly, we use
traces left by co-root lattices on K-groups, instead of co-roots themselves,
which had been used previously.


title:
Constraints on galaxy formation models from the galaxy stellar mass
  function and its evolution

abstract:
  We explore the parameter space of the semi-analytic galaxy formation model
GALFORM, studying the constraints imposed by measurements of the galaxy stellar
mass function (GSMF) and its evolution. We use the Bayesian Emulator method to
quickly eliminate vast implausible volumes of the parameter space and zoom in
on the most interesting regions, allowing us to identify a set of models that
match the observational data within model uncertainties. We find that the GSMF
strongly constrains parameters related to quiescent star formation in discs,
stellar and AGN feedback and threshold for disc instabilities, but weakly
restricts other parameters. Constraining the model using local data alone does
not usually select models that match the evolution of the GSMF well.
Nevertheless, we show that a small subset of models provides acceptable match
to GSMF data out to redshift 1.5. We explore the physical significance of the
parameters of these models, in particular exploring whether the model provides
a better description if the mass loading of the galactic winds generated by
starbursts ($\beta_{0,\text{burst}}$) and quiescent disks
($\beta_{0,\text{disc}}$) is different. Performing a principal component
analysis of the plausible volume of the parameter space, we write a set of
relations between parameters obeyed by plausible models with respect to GSMF
evolution. We find that while $\beta_{0,\text{disc}}$ is strongly constrained
by GSMF evolution data, constraints on $\beta_{0,\text{burst}}$ are weak.
Although it is possible to find plausible models for which
$\beta_{0,\text{burst}} = \beta_{0,\text{disc}}$, most plausible models have
$\beta_{0,\text{burst}}>\beta_{0,\text{disc}}$, implying - for these - larger
SN feedback efficiency at higher redshifts.


title: $A_p$-$A_\infty$ estimates for multilinear maximal and sparse operators

abstract:
  We obtain mixed $A_p$--$A_\infty$ estimates for a large family of multilinear
maximal and sparse operators. Operators from this family are known to control
for instance multilinear Calder\'on--Zygmund operators, square functions,
fractional integrals, and the bilinear Hilbert transform. Our results feature a
new multilinear version of the Fujii--Wilson $A_\infty$ characteristic that
allows us to recover the best known estimates in terms of the $A_p$
characteristic for dependent weights as a special case of the mixed
characteristic estimates for general tuples of weights.


title:
Size-dependent contact angle, and wetting and drying transition of a
  droplet adsorbed on to a spherical substrate: Line tension effect

abstract:
  The size-dependent contact angle and the drying and wetting morphological
transition are studied with respect to the volume change for a spherical
cap-shaped droplet placed on a spherical substrate. The line-tension effect is
included using the rigorous formula for the Helmholtz free energy in the
droplet capillary model. A morphological drying transition from a cap-shaped to
a spherical droplet occurs when the substrate is hydrophobic and the droplet
volume is small, similar to the transition predicted on a flat substrate. In
addition, a morphological wetting transition from a cap-shaped to a wrapped
spherical droplet occurs for a hydrophilic substrate and a large droplet
volume. The contact angle depends on the droplet size: it decreases as the
droplet volume increases when the line tension is positive, whereas it
increases when the line tension is negative. The spherical droplets and wrapped
droplets are stable when the line tension is positive and large.