title:
Approximation of Classification and Measures of Uncertainty in Rough Set
  on Two Universal Sets

abstract:
  The notion of rough set captures indiscernibility of elements in a set. But,
in many real life situations, an information system establishes the relation
between different universes. This gave the extension of rough set on single
universal set to rough set on two universal sets. In this paper, we introduce
approximation of classifications and measures of uncertainty basing upon rough
set on two universal sets employing the knowledge due to binary relations.


title:
The Robo-AO software: Fully autonomous operation of a laser guide star
  adaptive optics and science system

abstract:
  Robo-AO is the first astronomical laser guide star adaptive optics (AO)
system designed to operate completely independent of human supervision. A
single computer commands the AO system, the laser guide star, visible and
near-infrared science cameras (which double as tip-tip sensors), the telescope,
and other instrument functions. Autonomous startup and shutdown sequences as
well as concatenated visible observations were demonstrated in late 2011. The
fully robotic software is currently operating during a month long demonstration
of Robo-AO at the Palomar Observatory 60-inch telescope.


title: Guarantees of Total Variation Minimization for Signal Recovery

abstract:
  In this paper, we consider using total variation minimization to recover
signals whose gradients have a sparse support, from a small number of
measurements. We establish the proof for the performance guarantee of total
variation (TV) minimization in recovering \emph{one-dimensional} signal with
sparse gradient support. This partially answers the open problem of proving the
fidelity of total variation minimization in such a setting \cite{TVMulti}. In
particular, we have shown that the recoverable gradient sparsity can grow
linearly with the signal dimension when TV minimization is used. Recoverable
sparsity thresholds of TV minimization are explicitly computed for
1-dimensional signal by using the Grassmann angle framework. We also extend our
results to TV minimization for multidimensional signals. Stability of
recovering signal itself using 1-D TV minimization has also been established
through a property called "almost Euclidean property for 1-dimensional TV
norm". We further give a lower bound on the number of random Gaussian
measurements for recovering 1-dimensional signal vectors with $N$ elements and
$K$-sparse gradients. Interestingly, the number of needed measurements is lower
bounded by $\Omega((NK)^{\frac{1}{2}})$, rather than the $O(K\log(N/K))$ bound
frequently appearing in recovering $K$-sparse signal vectors.


title: Filamentary Accretion Flows in the Embedded Serpens South Protocluster

abstract:
  One puzzle in understanding how stars form in clusters is the source of mass
-- is all of the mass in place before the first stars are born, or is there an
extended period when the cluster accretes material which can continuously fuel
the star formation process? We use a multi-line spectral survey of the southern
filament associated with the Serpens South embedded cluster-forming region in
order to determine if mass is accreting from the filament onto the cluster, and
whether the accretion rate is significant. Our analysis suggests that material
is flowing along the filament's long axis at a rate of ~30Msol/Myr (inferred
from the N2H+ velocity gradient along the filament), and radially contracting
onto the filament at ~130Msol/Myr (inferred from HNC self-absorption). These
accretion rates are sufficient to supply mass to the central cluster at a
similar rate to the current star formation rate in the cluster. Filamentary
accretion flows may therefore be very important in the ongoing evolution of
this cluster.


title: Mean Field Energy Games in Wireless Networks

abstract:
  This work tackles the problem of energy-efficient distributed power control
in wireless networks with a large number of transmitters. The problem is
modeled by a dynamic game. Each transmitter-receiver communication is
characterized by a state given by the available energy and/or the individual
channel state and whose evolution is governed by certain dynamics. Since
equilibrium analysis in such a (stochastic) game is generally difficult and
even impossible, the problem is approximated by exploiting the large system
assumption. Under an appropriate exchangeability assumption, the corresponding
mean field game is well defined and studied in detail for special cases. The
main contribution of this work is to show how mean field games can be applied
to the problem under investigation and provide illustrative numerical results.
Our results indicate that this approach can lead to significant gains in terms
of energy-efficiency at the resulting equilibrium.


title: Embedding hairy black holes in a magnetic universe

abstract:
  Ernst's solution generating technique is adapted to Einstein-Maxwell theory
conformally (and minimally) coupled to a scalar field. This integrable system
enjoys a SU(2,1) symmetry which enables one to move, by Kinnersley
transformations, though the axisymmetric and stationary solution space,
building an infinite tower of physically inequivalent solutions. As a specific
application, metrics associated to scalar hairy black holes, such as the ones
discovered by Bocharova, Bronnikov, Melnikov and Bekenstein, are embedded in
the external magnetic field of the Melvin universe.


title: Inhomogenous loop quantum cosmology with matter

abstract:
  The linearly polarized Gowdy $T^3$ model with a massless scalar field with
the same symmetries as the metric is quantized by applying a hybrid approach.
The homogeneous geometry degrees of freedom are loop quantized, fact which
leads to the resolution of the cosmological singularity, while a Fock
quantization is employed for both matter and gravitational inhomogeneities.
Owing to the inclusion of the massless scalar field this system allows us to
modelize flat Friedmann-Robertson-Walker cosmologies filled with
inhomogeneities propagating in one direction. It provides a perfect scenario to
study the quantum back-reaction between the inhomogeneities and the polymeric
homogeneous and isotropic background.


title:
Beyond alternating permutations: Pattern avoidance in Young diagrams and
  tableaux

abstract:
  We investigate pattern avoidance in alternating permutations and
generalizations thereof. First, we study pattern avoidance in an alternating
analogue of Young diagrams. In particular, we extend Babson-West's notion of
shape-Wilf equivalence to apply to alternating permutations and so generalize
results of Backelin-West-Xin and Ouchterlony to alternating permutations.
Second, we study pattern avoidance in the more general context of permutations
with restricted ascents and descents. We consider a question of Lewis regarding
permutations that are the reading words of thickened staircase Young tableaux,
that is, permutations that have (k - 1) ascents followed by a descent, followed
by (k - 1) ascents, et cetera. We determine the relative sizes of the sets of
pattern-avoiding (k - 1)-ascent permutations in terms of the forbidden pattern.
Furthermore, we give inequalities in the sizes of sets of pattern-avoiding
permutations in this context that arise from further extensions of
shape-equivalence type enumerations.


title: The Cayley isomorphism property for groups of order 8p

abstract:
  For every prime $p>3$ we prove that $Q \times \mathbb{Z}_p$ and
$\mathbb{Z}_2^3 \times \mathbb{Z}_p$ are DCI- groups. This result completes the
description of CI-groups of order $8p$.


title:
Stationary and Transition Probabilities in Slow Mixing, Long Memory
  Markov Processes

abstract:
  We observe a length-$n$ sample generated by an unknown,stationary ergodic
Markov process (\emph{model}) over a finite alphabet $\mathcal{A}$. Given any
string $\bf{w}$ of symbols from $\mathcal{A}$ we want estimates of the
conditional probability distribution of symbols following $\bf{w}$, as well as
the stationary probability of $\bf{w}$. Two distinct problems that complicate
estimation in this setting are (i) long memory, and (ii) \emph{slow mixing}
which could happen even with only one bit of memory.
  Any consistent estimator in this setting can only converge pointwise over the
class of all ergodic Markov models. Namely, given any estimator and any sample
size $n$, the underlying model could be such that the estimator performs poorly
on a sample of size $n$ with high probability. But can we look at a length-$n$
sample and identify \emph{if} an estimate is likely to be accurate?
  Since the memory is unknown \emph{a-priori}, a natural approach is to
estimate a potentially coarser model with memory $k_n=\mathcal{O}(\log n)$. As
$n$ grows, pointwise consistent estimates that hold eventually almost surely
(eas) are known so long as the scaling of $k_n$ is not superlogarithmic in $n$.
Here, rather than eas convergence results, we want the best answers possible
with a length-$n$ sample. Combining results in universal compression with
Aldous' coupling arguments, we obtain sufficient conditions on the length-$n$
sample (even for slow mixing models) to identify when naive (i) estimates of
the conditional probabilities and (ii) estimates related to the stationary
probabilities are accurate; and also bound the deviations of the naive
estimates from true values.


title: Quantifying Opacity

abstract:
  Opacity is a general language-theoretic framework in which several security
properties of a system can be expressed. Its parameters are a predicate, given
as a subset of runs of the system, and an observation function, from the set of
runs into a set of observables. The predicate describes secret information in
the system and, in the possibilistic setting, it is opaque if its membership
cannot be inferred from observation.
  In this paper, we propose several notions of quantitative opacity for
probabilistic systems, where the predicate and the observation function are
seen as random variables. Our aim is to measure (i) the probability of opacity
leakage relative to these random variables and (ii) the level of uncertainty
about membership of the predicate inferred from observation. We show how these
measures extend possibilistic opacity, we give algorithms to compute them for
regular secrets and observations, and we apply these computations on several
classical examples. We finally partially investigate the non-deterministic
setting.


title: Optimization of the Target Subsystem for the New g-2 Experiment

abstract:
  A precision measurement of the muon anomalous magnetic moment, $a_{\mu} =
(g-2)/2$, was previously performed at BNL with a result of 2.2 - 2.7 standard
deviations above the Standard Model (SM) theoretical calculations. The same
experimental apparatus is being planned to run in the new Muon Campus at
Fermilab, where the muon beam is expected to have less pion contamination and
the extended dataset may provide a possible $7.5\sigma$ deviation from the SM,
creating a sensitive and complementary bench mark for proposed SM extensions.
We report here on a preliminary study of the target subsystem where the
apparatus is optimized for pions that have favorable phase space to create
polarized daughter muons around the magic momentum of 3.094 GeV/c, which is
needed by the downstream g 2 muon ring.


title: A Decreasing Stack and an Increasing Stack in Series

abstract:
  We study a sorting machine consisting of two stacks in series where the first
stack has the added restriction such that entries in the stack must be in
decreasing order from top to bottom. We give the basis of the class of
permutations that are sortable by this machine which shows that it is
enumerated by the Schr\"oder numbers.


title: Algorithms for Generating Large-scale Clustered Random Graphs

abstract:
  Real social networks are often compared to random graphs in order to assess
whether their typological structure could be the result of random processes.
However, an Erd\H{o}s-R\'enyi random graph in large scale is often lack of
local structure beyond the dyadic level and as a result we need to generate the
clustered random graph instead of the simple random graph to compare the local
structure at the triadic level. In this paper a generalized version of
Gleeson's algorithm is advanced to generate a clustered random graph in
large-scale which persists the number of nodes |V|, the number of edges |E|,
and the global clustering coefficient C{\Delta} as in the real network. And it
also has advantages in randomness evaluation and computation time when
comparing with the existing algorithms.


title: Classically Isospinning Hopf Solitons

abstract:
  We perform full three-dimensional numerical relaxations of isospinning Hopf
solitons with Hopf charge up to 8 in the Skyrme-Faddeev model with mass terms
included. We explicitly allow the soliton solution to deform and to break the
symmetries of the static configuration. It turns out that the model with its
rich spectrum of soliton solutions, often of similar energy, allows for
transmutations, formation of new solution types and the rearrangement of the
spectrum of minimal-energy solitons in a given topological sector when isospin
is added. We observe that the shape of isospinning Hopf solitons can differ
qualitatively from that of the static solution. In particular the solution type
of the lowest energy soliton can change. Our numerical results are of relevance
for the quantization of the classical soliton solutions.


title: Quantum Information-Flow Security: Noninterference and Access Control

abstract:
  Quantum cryptography has been extensively studied in the last twenty years,
but information-flow security of quantum computing and communication systems
has been almost untouched in the previous research. Duo to the essential
difference between classical and quantum systems, formal methods developed for
classical systems, including probabilistic systems, cannot be directly applied
to quantum systems. This paper defines an automata model in which we can
rigorously reason about information-flow security of quantum systems. The model
is a quantum generalisation of Goguen and Meseguer's noninterference. The
unwinding proof technique for quantum noninterference is developed, and a
certain compositionality of security for quantum systems is established. The
proposed formalism is then used to prove security of access control in quantum
systems.


title:
Using Light Charged Particles to Probe the Asymmetry Dependence of the
  Nuclear Caloric Curve

abstract:
  Recently, we observed a clear dependence of the nuclear caloric curve on
neutron-proton asymmetry $\frac{N-Z}{A}$ through examination of fully
reconstructed equilibrated quasi-projectile sources produced in heavy ion
collisions at E/A = 35 MeV. In the present work, we extend our analysis using
multiple light charged particle probes of the temperature. Temperatures are
extracted with five distinct probes using a kinetic thermometer approach.
Additionally, temperatures are extracted using two probes within a chemical
thermometer approach (Albergo method). All seven measurements show a
significant linear dependence of the source temperature on the source
asymmetry. For the kinetic thermometer, the strength of the asymmetry
dependence varies with the probe particle species in a way which is consistent
with an average emission-time ordering.


title: The Open Cluster NGC 2437 (Messier 46)

abstract:
  The stellar content of the open cluster NGC 2437 (Messier 46) is investigated
using moderately deep u*,g', and r' MegaCam images. When compared with solar
metallicity isochrones, the (g', u'-g') and (r', g'-r') CMDs are consistent
with an age log(t_yr) = 8.35 +/- 0.15, a distance modulus 11.05 +/- 0.05, and a
color excess E(B-V) = 0.115 +/- 0.035. The r' luminosity function (LF) of main
sequence stars in the magnitude range r' < 17 (i.e. masses > 0.8 solar) has a
shape that follows solar neighborhood star counts. However, at fainter
magnitudes the cluster LF is flat, in contrast with what would be expected from
solar neighborhood counts. The clustering properties of stars in NGC 2437 are
investigated by examining the two-point angular correlation functions of main
sequence stars in different brightness ranges. Main sequence stars fainter than
r' = 17 are less centrally concentrated than brighter stars and are found over
a larger area of the sky, suggesting that there is a corona of faint main
sequence stars around NGC 2437. Based on the flat LF and extended spatial
distribution of faint stars, it is concluded that NGC 2437 is actively shedding
stars with masses < 0.8 solar.


title: Modified Stern-Brocot Sequences

abstract:
  We present the classical Stern-Brocot tree and provide a new proof of the
fact that every rational number between 0 and 1 appears in the tree. We then
generalize theStern-Brocot tree to allow for arbitrary choice of starting
terms, and prove that in all cases the tree maintains the property that every
rational number between the two starting terms appears exactly once.


title: The MICA Experiment: Astrophysics in Virtual Worlds

abstract:
  We describe the work of the Meta-Institute for Computational Astrophysics
(MICA), the first professional scientific organization based in virtual worlds.
MICA was an experiment in the use of this technology for science and
scholarship, lasting from the early 2008 to June 2012, mainly using the Second
Life and OpenSimulator as platforms. We describe its goals and activities, and
our future plans. We conducted scientific collaboration meetings, professional
seminars, a workshop, classroom instruction, public lectures, informal
discussions and gatherings, and experiments in immersive, interactive
visualization of high-dimensional scientific data. Perhaps the most successful
of these was our program of popular science lectures, illustrating yet again
the great potential of immersive VR as an educational and outreach platform.
While the members of our research groups and some collaborators found the use
of immersive VR as a professional telepresence tool to be very effective, we
did not convince a broader astrophysics community to adopt it at this time,
despite some efforts; we discuss some possible reasons for this non-uptake. On
the whole, we conclude that immersive VR has a great potential as a scientific
and educational platform, as the technology matures and becomes more broadly
available and accepted.


title: Skeletal Representations and Applications

abstract:
  When representing a solid object there are alternatives to the use of
traditional explicit (surface meshes) or implicit (zero crossing of implicit
functions) methods. Skeletal representations encode shape information in a
mixed fashion: they are composed of a set of explicit primitives, yet they are
able to efficiently encode the shape's volume as well as its topology. I will
discuss, in two dimensions, how symmetry can be used to reduce the
dimensionality of the data (from a 2D solid to a 1D curve), and how this
relates to the classical definition of skeletons by Medial Axis Transform.
While the medial axis of a 2D shape is composed of a set of curves, in 3D it
results in a set of sheets connected in a complex fashion. Because of this
complexity, medial skeletons are difficult to use in practical applications.
Curve skeletons address this problem by strictly requiring their geometry to be
one dimensional, resulting in an intuitive yet powerful shape representation.
In this report I will define both medial and curve skeletons and discuss their
mutual relationship. I will also present several algorithms for their
computation and a variety of scenarios where skeletons are employed, with a
special focus on geometry processing and shape analysis.


title: On novel string theories from 4d gauge theories

abstract:
  We investigate strings theories as defined from four dimensional gauge
theories. It is argued that novel (super)string theories exist up to 26
dimensions. Some of them may support weakly curved geometries.


title: Realistic neutron star constraints on bosonic asymmetric dark matter

abstract:
  It has been argued that the existence of old neutron stars excludes the
possibility of non-annihilating light bosonic dark matter, such as that arising
in asymmetric dark matter scenarios. If non-annihilating dark matter is
captured by neutron stars, the density will eventually become sufficient for
black hole formation. However, the dynamics of collapse is highly sensitive to
dark-matter self-interactions. Repulsive self-interactions, even if extremely
weak, can prevent black hole formation. We argue that self-interactions will
necessarily be present, and estimate their strength in representative models.
We also consider co-annihilation of dark matter with nucleons, which arises
naturally in many asymmetric dark matter models, and which again acts to
prevent black hole formation. We demonstrate how the excluded region of the
dark-matter parameter space shrinks as the strength of such interactions is
increased, and conclude that neutron star observations do not exclude most
realistic bosonic asymmetric dark matter models.


title:
A brief report on statistical study of net electric current in solar
  active regions with longitudinal fields of opposite polarity

abstract:
  Dynamic processes occurring in solar active regions are dominated by the
solar magnetic field. As of now, observations using a solar magnetograph have
supplied us with the vector components of a solar photospheric magnetic field.
The two transverse components of a photospheric magnetic field allow us to
compute the amount of electric current. We found that the electric current in
areas with positive (negative) polarity due to the longitudinal magnetic field
have both positive and negative signs in an active region, however, the net
current is found to be an order-of-magnitude less than the mean absolute
magnitude and has a preferred sign. In particular, we have statistically found
that there is a systematic net electric current from areas with negative
(positive) polarity to areas with positive (negative) polarity in solar active
regions in the northern (southern) hemisphere, but during the solar minimum
this tendency is reversed over time at some latitudes. The result indicates
that there is weak net electric current in areas of solar active regions with
opposite polarity, thus providing further details about the hemispheric
helicity rule found in a series of previous studies.


title:
Polarization-resolved extinction and scattering cross-section of
  individual gold nanoparticles measured by wide-field microscopy on a large
  ensemble

abstract:
  We report a simple, rapid, and quantitative wide-field technique to measure
the optical extinction $\sigma_{\rm ext}$ and scattering $\sigma_{\rm sca}$
cross-section of single nanoparticles using wide-field microscopy enabling
simultaneous acquisition of hundreds of nanoparticles for statistical analysis.
As a proof of principle, we measured nominally spherical gold nanoparticles of
40\,nm and 100\,nm diameter and found mean values and standard deviations of
$\sigma_{\rm ext}$ and $\sigma_{\rm sca}$ consistent with previous literature.
Switching from unpolarized to linearly polarized excitation, we measured
$\sigma_{\rm ext}$ as a function of the polarization direction, and used it to
characterize the asphericity of the nanoparticles. The method can be
implemented cost-effectively on any conventional wide-field microscope and is
applicable to any nanoparticles.


title: A Sampling Theorem for Computational Diffraction

abstract:
  A major challenge of many diffraction calculations, using some form of the
Rayleigh-Sommerfeld formulas, is the integration of a highly oscillatory
integrand. Here we derive a potentially useful alternative form of solution to
the Helmholtz equation, which implies a sampling theorem for the evaluation of
a diffracted scalar field. This alternative solution bears close resemblance to
the Rayleigh-Sommerfeld diffraction formulas, but instead incorporates the
boundary conditions digitally. Hence, the integration is replaced by a simple
summation. This formulation may be more efficient for accurate computer-based
calculation of the diffracted scalar field.


title: Recent developments in SU(3) covariant baryon chiral perturbation theory

abstract:
  Baryon chiral perturbation theory (BChPT), as an effective field theory of
low-energy quantum chromodynamics (QCD), has played and is still playing an
important role in our understanding of non-perturbative strong interaction
phenomena. In the past two decades, inspired by the rapid progress in lattice
QCD simulations and the new experimental campaign to study the strangeness
sector of low-energy QCD, many efforts have been made to develop a fully
covariant BChPT and to test its validity in all scenarios. These new endeavours
have not only deepened our understanding of some long-standing problems, such
as the power-counting-breaking problem and the convergence problem, but also
resulted in theoretical tools that can be confidently applied to make robust
predictions. Particularly, the manifestly covariant BChPT supplemented with the
extended-on-mass-shell (EOMS) renormalization scheme has been shown to satisfy
all analyticity and symmetry constraints and converge relatively faster
compared to its non-relativistic and infrared counterparts. In this article, we
provide a brief review of the fully covariant BChPT and its latest applications
in the $u$, $d$, and $s$ three-flavor sector.


title: Amalgamating R^\omega-embeddable von Neumann algebras

abstract:
  We observe how a classical model-theoretic fact proves the existence of many
strong amalgamation bases for the class of R^\omega-embeddable von Neumann
algebras, where R is the hyperfinite II_1 factor. In particular, we shows that
R itself is a strong amalgamation base.


title: On the definition of homological critical value

abstract:
  We point out that there is a problem with the definition of homological
critical value (as defined in the widely cited paper \cite{stability} by
Cohen-Steiner, Edelsbrunner and Harer). Under that definition, the critical
value lemma of \cite{stability} in fact fails. We provide several
counterexamples and a definition (due to Bubenik and Scott
\cite{categorification}) we feel should be preferred and under which the
critical value lemma does indeed hold. One of the counterexamples we have found
is a height function on a compact smooth manifold. In the end we prove that,
despite all this, a modified version of the critical value lemma remains valid
under the original definition.


title: Gamma-ray polarization induced by cold electrons via Compton processes

abstract:
  The polarization measurement is an important tool to probe the prompt
emission mechanism in gamma-ray bursts (GRBs). The synchrotron photons can be
scattered by cold electrons in the outflow via Compton scattering processes.
The observed polarization depends on both the photon energy and the viewing
angle. With the typical bulk Lorentz factor $\Gamma \sim 200$, photons with
energy $E>10$ MeV tend to have smaller polarization than photons with energy
$E<1$ MeV. At the right viewing angle, i.e. $\theta \sim \Gamma^{-1}$, the
polarization achieves its maximal value, and the polarization angle changes
$90^{\circ}$ relative to the initial polarization direction. Thus, the
synchrotron radiation plus Compton scattering model can naturally explain the
$90^{\circ}$ change of the polarization angle in GRB 100826A.


title:
Generalized Yetter-Drinfel'd module categories for regular multiplier
  Hopf algebras

abstract:
  For a regular multiplier Hopf algebra $A$, the Yetter-Drinfel'd module
category ${}_{A}\mathcal{YD}^{A}$ is equivalent to the centre
$Z({}_{A}\mathcal{M})$ of the unital left $A$-module category
${}_{A}\mathcal{M}$. Then we introduce the generalized $(\alpha,
\beta)$-Yetter-Drinfel'd module categories ${}_{A}\mathcal{GYD}^{A}(\alpha,
\beta)$, which are treated as components of a braided $T$-category. Especially
when $A$ is a coFrobenius Hopf algebra, ${}_{A}\mathcal{YD}^{A}(\alpha, \beta)$
is isomorphic to the unital $\hat{A} \bowtie A(\alpha, \beta)$-module category
${}_{\hat{A} \bowtie A(\alpha, \beta)}\mathcal{M}$. Finally for a
Yetter-Drinfel'd $A$-module algebra $H$, we introduce Yetter-Drinfel'd $(H,
A)$-module category, which is a monoidal.


title: A Generalized Closed Form For Triangular Matrix Powers

abstract:
  This paper shows how to obtain a simple closed form for the elements of a
triangular matrix raised to the nth power.


title: Effect of Dilution on Spinodals and Pseudospinodals

abstract:
  We investigate the effect of quenched dilution on the critical and spinodal
points in the infinite range (mean-field) and long-range (near-mean-field)
Ising model. We find that unlike the short-range Ising model, the effect of the
dilution is not simply related to the divergence of the specific heat, i.e.,
the Harris criterion. We also find the mean-field behavior differs from that of
$d=4$ (upper critical dimension) nearest neighbor model at the critical point.
These results are an important first step for understanding the effect of the
spinodal on the nucleation process as well as the properties of the metastable
state in systems of considerable interest in material science, geophysics, and
econophysics which in general have defects.


title: Discrimination in Online Ad Delivery

abstract:
  A Google search for a person's name, such as "Trevon Jones", may yield a
personalized ad for public records about Trevon that may be neutral, such as
"Looking for Trevon Jones?", or may be suggestive of an arrest record, such as
"Trevon Jones, Arrested?". This writing investigates the delivery of these
kinds of ads by Google AdSense using a sample of racially associated names and
finds statistically significant discrimination in ad delivery based on searches
of 2184 racially associated personal names across two websites. First names,
assigned at birth to more black or white babies, are found predictive of race
(88% black, 96% white), and those assigned primarily to black babies, such as
DeShawn, Darnell and Jermaine, generated ads suggestive of an arrest in 81 to
86 percent of name searches on one website and 92 to 95 percent on the other,
while those assigned at birth primarily to whites, such as Geoffrey, Jill and
Emma, generated more neutral copy: the word "arrest" appeared in 23 to 29
percent of name searches on one site and 0 to 60 percent on the other. On the
more ad trafficked website, a black-identifying name was 25% more likely to get
an ad suggestive of an arrest record. A few names did not follow these
patterns. All ads return results for actual individuals and ads appear
regardless of whether the name has an arrest record in the company's database.
The company maintains Google received the same ad text for groups of last names
(not first names), raising questions as to whether Google's technology exposes
racial bias.


title: Cluster packing geometry for Al-based F-type icosahedral alloys

abstract:
  This paper presents a new highly stable periodic approximant to the Al-based
F-type icosahedral quasicrystals, i-Al-Pd-TM (TM=transition metals). The
structure of this intermetallic Al-Pd-Cr-Fe compound is determined ab initio
using single-crystal X-ray diffraction, where the space group is identified to
be Pa-3 and the lattice constant 40.5 angstrom. The structure is well described
as a dense packing of clusters of two kinds, which are known in the literature
as the pseudo-Mackay type and the Bergman type clusters. The clusters are
centered at the vertices of a canonical cell tiling, in which the parity of
each vertex determines the kind of the associated cluster. Adjacent clusters
can be markedly interpenetrated, while the structure requires no glue atoms to
fill in the gaps between the clusters. It is shown that the crystal can be
designated as a 2x2x2 superstructure of the ordinary cubic 3/2 rational
approximant. The superlattice ordering is shown to be of a different kind from
the P-type superlattice ordering previously reported in i-Al-Pd-Mn. The present
results will greatly improve the understanding of atomic structures of F-type
icosahedral quasicrystals and their approximants.


title: Exploration of Galactic {\gamma}-Ray Supernova Remnants

abstract:
  New generational very-high-energy telescope arrays have been detecting more
than 120 TeV {\gamma}-ray sources. Multi-wavelength observations on these
Gamma-ray sources have proven to be robust in shedding light on their nature.
The coming radio telescope arrays like ASKAP and FAST may find more faint
(extended) radio sources due to their better sensitivities and resolutions,
might identify more previously un-identified {\gamma}-ray sources and set many
new targets for future deep surveys by very-high-energy ground-based telescopes
like LHAASO. We in the paper summarize a list of known Galactic {\gamma}-ray
Supernova Remnants (SNRs) with or without radio emissions so far, which
includes some SNRs deserving top priority for future multi-wavelength
observations.


title: Musielak-Orlicz Campanato Spaces and Applications

abstract:
  Let $\varphi: \mathbb R^n\times [0,\infty)\to[0,\infty)$ be such that
$\varphi(x,\cdot)$ is an Orlicz function and $\varphi(\cdot,t)$ is a
Muckenhoupt $A_\infty(\mathbb R^n)$ weight uniformly in $t$. In this article,
the authors introduce the Musielak-Orlicz Campanato space ${\mathcal
L}_{\varphi,q,s}({\mathbb R}^n)$ and, as an application, prove that some of
them is the dual space of the Musielak-Orlicz Hardy space $H^{\varphi}(\mathbb
R^n)$, which in the case when $q=1$ and $s=0$ was obtained by L. D. Ky [arXiv:
1105.0486]. The authors also establish a John-Nirenberg inequality for
functions in ${\mathcal L}_{\varphi,1,s}({\mathbb R}^n)$ and, as an
application, the authors also obtain several equivalent characterizations of
${\mathcal L}_{\varphi,q,s}({\mathbb R}^n)$, which, in return, further induce
the $\varphi$-Carleson measure characterization of ${\mathcal
L}_{\varphi,1,s}({\mathbb R}^n)$.


title: Finite groups in which SS-permutability is a transitive relation

abstract:
  A subgroup $H$ of a finite group $G$ is said to be SS-permutable in $G$ if
$H$ has a supplement $K$ in $G$ such that $H$ permutes with every Sylow
subgroup of $K$. A finite group $G$ is called an SST-group if SS-permutability
is a transitive relation on the set of all subgroups of $G$. The structure of
SST-groups is investigated in this paper.


title: Hellmann and Feynman theorem versus diffusion Monte Carlo experiment

abstract:
  In a computer experiment the choice of suitable estimators to measure a
physical quantity plays an important role. We propose a new direct route to
determine estimators for observables which do not commute with the Hamiltonian.
Our new route makes use of the Hellmann and Feynman theorem and in a diffusion
Monte Carlo simulation it introduces a new bias to the measure due to the
choice of the auxiliary function. This bias is independent from the usual one
due to the choice of the trial wave function. We used our route to measure the
radial distribution function of a spin one half Fermion fluid.


title: Ising-like transitions in the O($n$) loop model on the square lattice

abstract:
  We explore the phase diagram of the O($n$) loop model on the square lattice
in the $(x,n)$ plane, where $x$ is the weight of a lattice edge covered by a
loop. These results are based on transfer-matrix calculations and finite-size
scaling. We express the correlation length associated with the staggered loop
density in the transfer-matrix eigenvalues. The finite-size data for this
correlation length, combined with the scaling formula, reveal the location of
critical lines in the diagram. For $n>>2$ we find Ising-like phase transitions
associated with the onset of a checkerboard-like ordering of the elementary
loops, i.e., the smallest possible loops, with the size of an elementary face,
which cover precisely one half of the faces of the square lattice at the
maximum loop density. In this respect, the ordered state resembles that of the
hard-square lattice gas with nearest-neighbor exclusion, and the finiteness of
$n$ represents a softening of its particle-particle potentials. We also
determine critical points in the range $-2\leq n\leq 2$. It is found that the
topology of the phase diagram depends on the set of allowed vertices of the
loop model. Depending on the choice of this set, the $n>2$ transition may
continue into the dense phase of the $n \leq 2$ loop model, or continue as a
line of $n \leq 2$ O($n$) multicritical points.


title:
Spin/orbit moment imbalance in the near-zero moment ferromagnetic
  semiconductor SmN

abstract:
  SmN is ferromagnetic below 27 K, and its net magnetic moment of 0.03 Bohr
magnetons per formula unit is one of the smallest magnetisations found in any
ferromagnetic material. The near-zero moment is a result of the nearly equal
and opposing spin and orbital moments in the 6H5/2 ground state of the Sm3+
ion, which leads finally to a nearly complete cancellation for an ion in the
SmN ferromagnetic state. Here we explore the spin alignment in this compound
with X-ray magnetic circular dichroism at the Sm L2,3 edges. The spectral
shapes are in qualitative agreement with computed spectra based on an LSDA+U
(local spin density approximation with Hubbard-U corrections) band structure,
though there remain differences in detail which we associate with the anomalous
branching ratio in rare-earth L edges. The sign of the spectra determine that
in a magnetic field the Sm 4f spin moment aligns antiparallel to the field; the
very small residual moment in ferromagnetic SmN aligns with the 4f orbital
moment and antiparallel to the spin moment. Further measurements on very thin
(1.5 nm) SmN layers embedded in GdN show the opposite alignment due to a strong
Gd-Sm exchange, suggesting that the SmN moment might be further reduced by
about 0.5 % Gd substitution.


title:
Heavy quark dynamics for charm and bottom flavor on Fermi surface at
  zero temperature

abstract:
  We discuss the dynamics in finite density medium including a heavy impurity
particle (hadron or quark) with a heavy flavor, charm and bottom, at zero
temperature. As a system, we consider a $\bar{D}$ ($B$) meson embedded in
nuclear matter as a heavy impurity boson with SU(2) isospin symmetry. As
another system, we also consider a charm (bottom) quark embedded in quark
matter as a heavy impurity fermion with SU(3) color symmetry. We suppose a
vector current interaction with SU($n$) symmetry ($n \ge 2$) for the fermion
composing the Fermi surface and the embedded heavy impurity particle, and
calculate the scattering amplitude perturbatively for the small coupling
constant up to one-loop level. We obtain that the scattering amplitude has a
logarithmic enhancement in the large mass limit of the heavy impurity particle,
and show that the perturbative calculation breaks down for any small coupling
constant in this limit.


title:
Plasmon modes in the magnetically doped Single Layer and Multilayers of
  Helical Metals

abstract:
  We study the plasmon excitations and the electromagnetic response of the
magnetically doped single layer and multilayer of ``helical metals'', which
emerge at the surfaces of topological insulators. For the single layer case, we
find a ``spin-plasmon'' mode with the rotating spin texture due to the
combination of the spin-momentum locking of ``helical metals'' and the Hall
response from magnetization. For the multilayers case, we investigate the
electromagnetic response due to the plasmon excitations, including the Faraday
rotation for the light propagating normal to the helical metal layers and an
additional optical mode with the frequency within the conventional plasmon gap
for the light propagating along the helical metal layers.


title:
QCD ghost dark energy cannot (even roughly) explain the main features of
  the accepted cosmological paradigm

abstract:
  We explore the whole phase space of the so called Veneziano/QCD ghost dark
energy models where the dynamics of the inner trapping horizon is ignored and
also the more realistic models where the time-dependence of the horizon is
taken into consideration. We pay special attention to the choice of phase space
variables leading to bounded and compact phase space so that no critical point
of physical interest is missing. It is demonstrated that ghost dark energy is
not a suitable candidate to explain the presently accepted cosmological
paradigm since no critical point associated with matter dominance is found in
the physical phase space of the model. A transient stage of matter dominance --
responsible for the observed amount of cosmic structure -- is an essential
ingredient of the accepted cosmological paradigm. The above drawback is in
addition to the well known problem with classical instability against small
perturbations of the background density originated from negativity of the sound
speed squared.


title: Galilean Islands in Eternally Inflating Background

abstract:
  We show that the observational universe may emerge classically from a de
Sitter background with low energy scale. We find, after calculating the
curvature perturbation, that the resulting scenario is actually a style of the
eternal inflation scenario, in which some regions will go through the slowly
expanding Galilean genesis phase with the rapidly increasing energy density and
become island universes, while other regions are still eternally inflating,
which will make the room for more island universes to emerge.


title: Chiral-Dependent Tensile Mechanics of Graphene

abstract:
  We report a molecular dynamics study on the tensile mechanics of graphene as
gradually rotating the tensile direction from armchair to zigzag direction,
covering the complete range of chiral directions which has never been explored
so far. We observed monotonic increases of tensile strength and strain as the
chiral (rotational) angle increases. Key feature is their negligible changes up
to chiral angle of ~12{\deg} and the subsequent rapid increases and this
pattern holds for all temperatures examined here (100-700 K). Considering a
topologically consistent (zigzag-lines) breaking of graphene, we presented a
unified fracture model that successfully reproduced the simulation results as
well as explaining their physical origin. Notably, we found that the elastic
stress of graphene is quasi-isotropic for all chiral directions in contrast to
its anisotropic fracture behavior. Through the indentation simulations of
graphene, we demonstrated that our rationale established in uniaxial (1D)
tensile systems is applicable to 2D tensile systems as well.


title:
Orthogonal almost complex structures on the Riemannian products of
  even-dimensional round spheres

abstract:
  We discuss the integrability of orthogonal almost complex structures on
Riemannian products of even-dimensional round spheres and give a partial answer
to the question raised by E. Calabi concerning the existence of complex
structures on a product manifold of a round 2-sphere and a round 4-sphere.


title: Towards Interactive Object-Oriented Programming

abstract:
  To represent interactive objects, we propose a choice-disjunctive declaration
statement of the form S R where S;R are the (procedure or field) declaration
statements within a class. This statement has the following semantics: request
the user to choose one between S and R when an object of this class is created.
This statement is useful for representing interactive objects that require
interactions with the user.


title:
Preserving Privacy of Mobile Reader Holders in Server-less RFID
  Authentication and Searching Protocols

abstract:
  Along with the development of internet of things and pervasive computing,
researchers are increasingly focusing on server-less RFID authentication and
searching protocols, which utilize mobile RFID readers. However, revealing
privacy of mobile reader holders is a widely neglected problem in current
research. This paper concentrates on preserving privacy of mobile reader
holders in server-less RFID authentication and searching protocols. We propose
a detailed requirement as a principle for future protocol designs, and a scheme
to enhance most current protocols. We apply our scheme to two classical
protocols. The comparisons between the original and our enhanced protocols show
that our scheme is secure and effective.


title: Reveal quantum correlation in complementary bases

abstract:
  An essential feature of genuine quantum correlation is the simultaneous
existence of correlation in complementary bases. We reveal this feature of
quantum correlation by defining measures based on invariance under a basis
change. For a bipartite quantum state, the classical correlation is the maximal
correlation present in a certain optimum basis, while the quantum correlation
is characterized as a series of residual correlations in the mutually unbiased
bases. Compared with other approaches to quantify quantum correlation, our
approach gives information-theoretical measures that directly reflect the
essential feature of quantum correlation.


title:
Computation of Growth Rates and Threshold of the Electromagnetic
  Electron Temperature Gradient Modes in Tokamaks

abstract:
  In this manuscript, eigenvalues of the Electron Temperature Gradient (ETG)
modes and Ion Temperature Gradient (ITG) modes are determined numerically using
Hermite and Sinc differentiation matrices based methods. It is shown that these
methods are very useful for the computation of growth rates and threshold of
the ETG and ITG modes. The total number of accurately computed eigenvalues for
the modes have also been computed. The ideas developed here are also of
relevance to other modes that use Ballooning formalism.

categories: physics.plasm-ph math-ph math.MP physics.comp-ph


title:
Small value probabilities for supercritical branching processes with
  immigration

abstract:
  We consider a supercritical Galton-Watson branching process with immigration.
It is well known that under suitable conditions on the offspring and
immigration distributions, there is a finite, strictly positive limit
${\mathcal{W}}$ for the normalized population size. Small value probabilities
for ${\mathcal{W}}$ are obtained. Precise effects of the balance between
offspring and immigration distributions are characterized.


title:
On the Universality of the Energy Response Function in the Long-Range
  Spin Glass Model with Sparse, Modular Couplings

abstract:
  We consider energy relaxation of the long-range spin glass model with sparse
couplings, the so-called dilute Sherrington-Kirkpatrick (SK) model, starting
from a random initial state. We consider the effect that modularity of the
coupling matrix has on this relaxation dynamics. In the absence of finite size
effects, the relaxation dynamics appears independent of modularity. For finite
sizes, a more modular system reaches a less favorable energy at long times. For
small sizes, a more modular system also has a less favorable energy at short
times. For large sizes, modularity appears to lead to slightly more favorable
energies at intermediate times. We discuss these results in the context of
evolutionary theory, where horizontal gene transfer, absent in the Glauber
equilibration dynamics of the SK model studied here, endows modular organisms
with larger response functions at short times.


title:
Weak extinction versus global exponential growth of total mass for
  superdiffusions

abstract:
  Consider a superdiffusion $X$ on $\mathbb R^d$ corresponding to the
semilinear operator $\mathcal{A}(u)=Lu+\beta u-ku^2,$ where $L$ is a second
order elliptic operator, $\beta(\cdot)$ is in the Kato class and bounded from
above, and $k(\cdot)\ge 0$ is bounded on compact subsets of $\R^d$ and is
positive on a set of positive Lebesgue measure.
  The main purpose of this paper is to complement the results obtained in
\cite{Englander:2004}, in the following sense. Let $\lambda_\infty $ be the
$L^\infty$-growth bound of the semigroup corresponding to the Schr\"odinger
operator $L+\beta $. If $\lambda_\infty \neq0$, then we prove that, in some
sense, the exponential growth/decay rate of $\|X_t\|$, the total mass of $X_t$,
is $\lambda_\infty $. We also describe the limiting behavior of
$\exp(-\lambda_\infty t)\|X_t\|$ in these cases. This should be compared to the
result in \cite{Englander:2004}, which says that the generalized principal
eigenvalue $\lambda_2$ of the operator gives the rate of {\it local} growth
when it is positive, and implies local extinction otherwise. It is easy to show
that $\lambda_{\infty}\ge \lambda_2$, and we discuss cases when
$\lambda_{\infty}> \lambda_2$ and when $\lambda_{\infty}= \lambda_2$.
  When $\lambda_\infty =0$, and under some conditions on $\beta$, we give a
sufficient and necessary condition for the superdiffusion $X$ to exhibit weak
extinction. We show that the branching intensity $k$ affects weak extinction;
this should be compared to the known result that $k$ does not affect weak {\it
local} extinction (which only depends on the sign of $\lambda_2$, and which
turns out to be equivalent to local extinction) of $X$.


title: ChaMAILeon: Simplified email sharing like never before!

abstract:
  While passwords, by definition, are meant to be secret, recent trends in the
Internet usage have witnessed an increasing number of people sharing their
email passwords for both personal and professional purposes. As sharing
passwords increases the chances of your passwords being compromised, leading
websites like Google strongly advise their users not to share their passwords
with anyone. To cater to this conflict of usability versus security and
privacy, we introduce ChaMAILeon, an experimental service, which allows users
to share their email passwords while maintaining their privacy and not
compromising their security. In this report, we discuss the technical details
of the implementation of ChaMAILeon.


title: Twisted Reidemeister torsion, the Thurston norm and fibered manifolds

abstract:
  We prove that the twisted Reidemeister torsion of a 3-manifold corresponding
to a fibered class is monic and we show that it gives lower bounds on the
Thurston norm. The former fixes a flawed proof in [FV10], the latter gives a
quick alternative argument for the main theorem of [FK06].


title:
Explicit formulas for computing Bernoulli numbers of the second kind and
  Stirling numbers of the first kind

abstract:
  In the paper, by establishing a new and explicit formula for computing the
$n$-th derivative of the reciprocal of the logarithmic function, the author
presents new and explicit formulas for calculating Bernoulli numbers of the
second kind and Stirling numbers of the first kind. As consequences of these
formulas, a recursion for Stirling numbers of the first kind and a new
representation of the reciprocal of the factorial $n!$ are derived. Finally,
the author finds several identities and integral representations relating to
Stirling numbers of the first kind.


title: On the structure of sequentially Cohen--Macaulay bigraded modules

abstract:
  Let $K$ be a field and $S=K[x_1,\ldots,x_m, y_1,\ldots,y_n]$ be the standard
bigraded polynomial ring over $K$. In this paper, we explicitly describe the
structure of finitely generated bigraded "sequentially Cohen--Macaulay"
$S$-modules with respect to $Q=(y_1,\ldots,y_n)$. Next, we give a
characterization of sequentially Cohen--Macaulay modules with respect to $Q$ in
terms of local cohomology modules. Cohen--Macaulay modules that are
sequentially Cohen--Macaulay with respect to $Q$ are considered.


title: Robust Face Recognition via Block Sparse Bayesian Learning

abstract:
  Face recognition (FR) is an important task in pattern recognition and
computer vision. Sparse representation (SR) has been demonstrated to be a
powerful framework for FR. In general, an SR algorithm treats each face in a
training dataset as a basis function, and tries to find a sparse representation
of a test face under these basis functions. The sparse representation
coefficients then provide a recognition hint. Early SR algorithms are based on
a basic sparse model. Recently, it has been found that algorithms based on a
block sparse model can achieve better recognition rates. Based on this model,
in this study we use block sparse Bayesian learning (BSBL) to find a sparse
representation of a test face for recognition. BSBL is a recently proposed
framework, which has many advantages over existing block-sparse-model based
algorithms. Experimental results on the Extended Yale B, the AR and the CMU PIE
face databases show that using BSBL can achieve better recognition rates and
higher robustness than state-of-the-art algorithms in most cases.


title: The geometric mean is a Bernstein function

abstract:
  In the paper, the authors establish, by using Cauchy integral formula in the
theory of complex functions, an integral representation for the geometric mean
of $n$ positive numbers. From this integral representation, the geometric mean
is proved to be a Bernstein function and a new proof of the well known AG
inequality is provided.


title:
Mutual Redundancies in Inter-human Communication Systems: Steps Towards
  a Calculus of Processing Meaning

abstract:
  The study of inter-human communication requires a more complex framework than
Shannon's (1948) mathematical theory of communication because "information" is
defined in the latter case as meaningless uncertainty. Assuming that meaning
cannot be communicated, we extend Shannon's theory by defining mutual
redundancy as a positional counterpart of the relational communication of
information. Mutual redundancy indicates the surplus of meanings that can be
provided to the exchanges in reflexive communications. The information is
redundant because based on "pure sets," that is, without subtraction of mutual
information in the overlaps. We show that in the three-dimensional case (e.g.,
of a Triple Helix of university-industry-government relations), mutual
redundancy is equal to mutual information (Rxyz = Txyz); but when the
dimensionality is even, the sign is different. We generalize to the measurement
in N dimensions and proceed to the interpretation. Using Luhmann's
social-systems theory and/or Giddens' structuration theory, mutual redundancy
can be provided with an interpretation in the sociological case: different
meaning-processing structures code and decode with other algorithms. A surplus
of ("absent") options can then be generated that add to the redundancy.
Luhmann's "functional (sub)systems" of expectations or Giddens' "rule-resource
sets" are positioned mutually, but coupled operationally in events or
"instantiated" in actions. Shannon-type information is generated by the
mediation, but the "structures" are (re-)positioned towards one another as sets
of (potentially counterfactual) expectations. The structural differences among
the coding and decoding algorithms provide a source of additional options in
reflexive and anticipatory communications.


title:
Hierarchical Liouville-space approach to nonequilibrium dynamical
  properties of quantum impurity systems

abstract:
  We propose a hierarchical dynamics approach for evaluation of nonequilibrium
dynamic response properties of quantum impurity systems. It is based on a
hierarchical equations of motion formalism, in conjunction with a linear
response theory established in the hierarchical Liouville space. This provides
an accurate and universal tool for characterization of arbitrary response and
correlation functions of local impurities, as well as transport related
response properties. The practicality of our proposed approach is demonstrated
via the evaluation of various dynamical properties of a single-impurity
Anderson model. These include the impurity spectral density, local charge
fluctuation, local magnetic susceptibility, and current-voltage admittance, in
both equilibrium and nonequilibrium situations. The numerical results are
considered to achieve the quantitative accuracy, as long as they converge with
respect to the truncation of the hierarchy.


title:
On convergence of the projective integration method for stiff ordinary
  differential equations

abstract:
  We present a convergence proof of the projective integration method for a
class of deterministic multi-dimensional multi-scale systems which are amenable
to centre manifold theory. The error is shown to contain contributions
associated with the numerical accuracy of the microsolver, the numerical
accuracy of the macrosolver and the distance from the centre manifold caused by
the combined effect of micro- and macrosolvers, respectively. We corroborate
our results by numerical simulations.


title: Phase Description of Stochastic Oscillations

abstract:
  We introduce an invariant phase description of stochastic oscillations by
generalizing the concept of standard isophases. The average isophases are
constructed as sections in the state space, having a constant mean first return
time. The approach allows to obtain a global phase variable of noisy
oscillations, even in the cases where the phase is ill-defined in the
deterministic limit. A simple numerical method for finding the isophases is
illustrated for noise-induced switching between two coexisting limit cycles,
and for noise-induced oscillation in an excitable system. We also discuss how
to determine the isophases for experimentally observed irregular oscillations,
providing a basis for a refined phase description of observed oscillatory
dynamics.


title: Chaotic dynamics of the Bianchi IX universe in Gauss-Bonnet gravity

abstract:
  We investigate the dynamics of closed FRW universe and anisotropic Bianchi
type-IX universe characterized by two scale factors in a gravity theory
including a higher curvature (Gauss-Bonnet) term. The presence of the
cosmological constant creates a critical point of saddle type in the phase
space of the system. An orbit starting from a neighborhood of the separatrix
will evolve toward the critical point, and it eventually either expands to the
de Sitter space or collapses to the big crunch. In the closed FRW model, the
dynamics is reduced to hyperbolic motions in the two-dimensional center
manifold, and the system is not chaotic. In the anisotropic model, anisotropy
introduces the rotational mode, which interacts with the hyperbolic mode to
present a cylindrical structure of unstable periodic orbits in the neighborhood
of the critical point. Due to the non-integrability of the system, the
interaction of rotational and hyperbolic modes makes the system chaotic, making
it impossible for us to predict the final fate of the universe. We find that
the chaotic dynamics arises from the fact that orbits with even small
perturbations around the separatrix oscillate in the neighborhood of the
critical point before finally expanding or collapsing. The chaotic character is
also evidenced by the fractal structures in the basins of attraction.


title:
Exact hybrid particle/population simulation of rule-based models of
  biochemical systems

abstract:
  Detailed modeling and simulation of biochemical systems is complicated by the
problem of combinatorial complexity, an explosion in the number of species and
reactions due to myriad protein-protein interactions and post-translational
modifications. Rule-based modeling overcomes this problem by representing
molecules as structured objects and encoding their interactions as
pattern-based rules. This greatly simplifies the process of model
specification, avoiding the tedious and error prone task of manually
enumerating all species and reactions that can potentially exist in a system.
From a simulation perspective, rule-based models can be expanded
algorithmically into fully-enumerated reaction networks and simulated using a
variety of network-based simulation methods, provided that the network is not
exceedingly large. Alternatively, rule-based models can be simulated directly
using particle-based kinetic Monte Carlo methods. This "network-free" approach
produces exact stochastic trajectories with a computational cost that is
independent of network size. However, memory and run time costs increase with
the number of particles, limiting the size of system that can be feasibly
simulated. Here, we present a hybrid particle/population simulation method that
combines the best attributes of both the network-based and network-free
approaches. The method takes as input a rule-based model and a user-specified
subset of species to treat as population variables rather than as particles.
The model is then transformed by a process of "partial network expansion" into
a dynamically equivalent form that can be simulated using a population-adapted
network-free simulator. The transformation method has been implemented within
the open-source rule-based modeling platform BioNetGen, and resulting hybrid
models can be simulated using the particle-based simulator NFsim.


title:
Ruelle transfer operators for contact Anosov flows and decay of
  correlations

abstract:
  We prove exponential decay of correlations for H\"older continuous
observables with respect to any Gibbs measure for contact Anosov flows
admitting Pesin sets with exponentially small tails. This is achieved by
establishing strong spectral estimates for certain Ruelle transfer operators
for such flows.


title:
X-ray Point Source Populations Constituting the Galactic Ridge X-ray
  Emission

abstract:
  Apparently diffuse X-ray emission has been known to exist along the central
quarter of the Galactic Plane since the beginning of the X-ray astronomy, which
is referred to as the Galactic Ridge X-ray emission (GRXE). Recent deep X-ray
observations have shown that numerous X-ray point sources account for a large
fraction of the GRXE in the hard band (2-8 keV). However, the nature of these
sources is poorly understood. Using the deepest X-ray observations made in the
Chandra Bulge Field (Revnivtsev et al., 2009,2011), we present the result of a
coherent photometric and spectroscopic analysis of individual X-ray point
sources for the purpose of constraining their nature and deriving their
fractional contributions to the hard band continuum and Fe K\alpha line
emission of the GRXE. Based on the X-ray color-color diagram, we divided the
point sources into three groups: A (hard), B (soft and broad spectrum), and C
(soft and peaked spectrum). The group A sources are further decomposed
spectrally into thermal and non-thermal sources with different fractions in
different flux ranges. From their X-ray properties, we speculate that the group
A non-thermal sources are mostly AGNs and the thermal sources are mostly white
dwarf (WD) binaries such as magnetic and non-magnetic cataclysmic variables
(CVs), pre-CVs, and symbiotic stars, whereas the group B and C sources are
X-ray active stars in flares and quiescence, respectively. In the log N-log S
curve of the 2-8 keV band, the group A non-thermal sources is dominant above
about 10^{-14} erg cm^{-2} s^{-1}, which is gradually taken over by Galactic
sources in the fainter flux ranges. The Fe K\alpha emission is mostly from the
group A thermal (WD binaries) and the group B (X-ray active stars) sources.


title: On the Singularity of Multivariate Hermite Interpolation

abstract:
  In this paper we study the singularity of multivariate Hermite interpolation
of type total degree. We present a method to judge the singularity of the
interpolation scheme considered and by the method to be developed, we show that
all Hermite interpolation of type total degree on $m=d+k$ points in $\R^d$ is
singular if $d\geq 2k$. And then we solve the Hermite interpolation problem on
$m\leq d+3$ nodes completely. Precisely, all Hermite interpolations of type
total degree on $m\leq d+1$ points with $d\geq 2$ are singular; for $m=d+2$ and
$m=d+3$, only three cases and one case can produce regular Hermite
interpolation schemes, respectively. Besides, we also present a method to
compute the interpolation space for Hermite interpolation of type total degree.


title:
State-Dependent Electron Delocalization Dynamics at the Solute-Solvent
  Interface: Soft X-ray Absorption Spectroscopy and Ab Initio Calculations

abstract:
  Non-radiative decay channels in the L-edge fluorescence spectra from
transition metal-aqueous solutions give rise to spectral dips in X-ray
transmission spectra. Their origin is unraveled here using partial and inverse
partial fluorescence yields on the micro-jet combined with multi-reference ab
initio electronic structure calculations. Comparing Fe2+, Fe3+, and Co2+
systems we demonstrate unequivocally that spectral dips are due to a
state-dependent electron delocalization within the manifold of d-orbitals.


title:
Weighted variation inequalities for differential operators and singular
  integrals

abstract:
  We prove weighted strong $q$-variation inequalities with $2<q<\infty$ for
differential and singular integral operators. For the first family of operators
the weights used can be either Sawyer's one-sided $A^+_p$ weights or
Muckenhoupt's $A_p$ weights according to that the differential operators in
consideration are one-sided or symmetric. We use only Muckenhoupt's $A_p$
weights for the second family. All these inequalities hold equally in the
vector-valued case, that is, for functions with values in $\el^\rho$ for
$1<\rho<\infty$. As application, we show variation inequalities for mean
bounded positive invertible operators on $L^p$ with positive inverses.


title: Convergence analysis of a family of 14-node brick elements

abstract:
  In this paper, we will give convergence analysis for a family of 14-node
elements which was proposed by I. M. Smith and D. J. Kidger in 1992. The 14
DOFs are taken as the value at the eight vertices and six face-centroids. For
second-order elliptic problem, we will show that among all the Smith-Kidger
14-node elements, Type 1, Type 2 and type 5 elements can get the optimal
convergence order and Type 6 get lower convergence order. Motivated by the
proof, we also present a new 14-node nonconforming element. If we change the
DOFs into the value at the eight vertices and the integration value of six
faces, we show that Type 1, Type 2 and Type 5 keep the optimal convergence
order and Type 6 element improve one order accuracy which means that it also
get optimal convergence order.


title: Chiral expansion of moments of quark distributions

abstract:
  We present formulae for the chiral extrapolation of spin-dependent and
spin-independent moments of quark distributions of octet baryons, including
loop corrections and counterterms to leading non-analytic order. This analysis
allows for isospin breaking, and may be used for the chiral extrapolation of
both (2+1)- and (1+1+1)-flavor lattice QCD results. An example of such an
application is given, with the extrapolation formulae applied to recent (2 +
1)-flavor QCDSF/UKQCD Collaboration lattice results for the first
spin-independent and first two spin-dependent Mellin moments.


title: A new cubic nonconforming finite element on rectangles

abstract:
  A new nonconforming rectangle element with cubic convergence for the energy
norm is introduced. The degrees of freedom (DOFs) are defined by the twelve
values at the three Gauss points on each of the four edges. Due to the
existence of one linear relation among the above DOFs, it turns out the DOFs
are eleven. The nonconforming element consists of $P_2\oplus
\Span\{x^3y-xy^3\}$. We count the corresponding dimension for Dirichlet and
Neumann boundary value problems of second-order elliptic problems. We also
present the optimal error estimates in both broken energy and $L_2(\O)$ norms.
Finally, numerical examples match our theoretical results very well.


title:
A Helson-Szeg\"o theorem for subdiagonal subalgebras with applications
  to Toeplitz operators

abstract:
  We formulate and establish a noncommutative version of the well known
Helson-Szego theorem about the angle between past and future for subdiagonal
subalgebras. We then proceed to use this theorem to characterise the symbols of
invertible Toeplitz operators on the noncommutative Hardy spaces associated to
subdiagonal subalgebras.


title: A study of coherently coupled two-component Bose-Einstein Condensates

abstract:
  We present a self-consistent study of coherently coupled two-component
Bose-Einstein condensates. Finite spin-flipping coupling changes the first
order demixing phase transition for Bose-Bose mixtures to a second order phase
transition between an unpolarized and a polarized state. We analise the
excitation spectrum and the structure factor along the transition for a
homogeneous system. We discuss the main differences at the transition between a
coherent coupled gas and a two-component mixture. We finally study the ground
state when spin-(in)dependent trapping potentials are added to the system,
focusing on optical lattices, which give rise to interesting new
configurations.


title: On weakly S-embedded subgroups and weakly $\tau$-embedded subgroups

abstract:
  Let $G$ be a finite group. A subgroup $H$ of $G$ is said to be weakly
S-embedded in $G$ if there exists $K\unlhd G$ such that $HK$ is S-quasinormal
in $G$ and $H\cap K\leq H_{seG}$, where $H_{seG}$ is the subgroup generated by
all those subgroups of $H$ which are S-quasinormally embedded in $G$. We say
that $H$ is weakly $\tau$-embedded in $G$ if there exists $K\unlhd G$ such that
$HK$ is S-quasinormal in $G$ and $H\cap K\leq H_{\tau G}$, where $H_{\tau G}$
is the subgroup generated by all those subgroups of $H$ which are
$\tau$-quasinormal in $G$. In this paper, we study the properties of the weakly
S-embedded subgroups and the weakly $\tau$-embedded subgroups, and use them to
determine the structure of finite groups.


title: Convex valuations invariant under the Lorentz group

abstract:
  We give an explicit classification of translation-invariant,
Lorentz-invariant continuous valuations on convex sets. We also classify the
Lorentz-invariant even generalized valuations.


title: The cubic nonlinear Dirac equation

abstract:
  We present some results obtained in collaboration with prof. Piero D'Ancona
concerning global existence for the 3D cubic non linear massless Dirac equation
with a potential for small initial data in $H^1$ with slight additional
assumptions. The new crucial tool is given by the proof of some refined
endpoint Strichartz estimates.


title:
Third- and fourth-order constants of incompressible soft solids and the
  acousto-elastic effect

abstract:
  Acousto-elasticity is concerned with the propagation of small-amplitude waves
in deformed solids. Results previously established for the incremental
elastodynamics of exact non-linear elasticity are useful for the determination
of third- and fourth-order elastic constants, especially in the case of
incompressible isotropic soft solids, where the expressions are particularly
simple. Specifically, it is simply a matter of expanding the expression for
$\rho v^2$, where $\rho$ is the mass density and v the wave speed, in terms of
the elongation $e$ of a block subject to a uniaxial tension. The analysis shows
that in the resulting expression: $\rho v^2 = a + be + ce^2$, say, $a$ depends
linearly on $\mu$; $b$ on $\mu$ and $A$; and $c$ on $\mu$, $A$, and $D$, the
respective second-, third, and fourth-order constants of incompressible
elasticity, for bulk shear waves and for surface waves.


title: Fundamental groups, homology equivalences and one-sided h-cobordisms

abstract:
  We give a sufficient and necessary condition of the fundamental group
homomorphism of a map between manifolds to induce homology equivalences.
Moreover, a classification of one-sided h-cobordism of manifolds up to
diffeomorphisms is obtained, based on Quillen's plus construction with
Whitehead torsions.


title: Studying User Footprints in Different Online Social Networks

abstract:
  With the growing popularity and usage of online social media services, people
now have accounts (some times several) on multiple and diverse services like
Facebook, LinkedIn, Twitter and YouTube. Publicly available information can be
used to create a digital footprint of any user using these social media
services. Generating such digital footprints can be very useful for
personalization, profile management, detecting malicious behavior of users. A
very important application of analyzing users' online digital footprints is to
protect users from potential privacy and security risks arising from the huge
publicly available user information. We extracted information about user
identities on different social networks through Social Graph API, FriendFeed,
and Profilactic; we collated our own dataset to create the digital footprints
of the users. We used username, display name, description, location, profile
image, and number of connections to generate the digital footprints of the
user. We applied context specific techniques (e.g. Jaro Winkler similarity,
Wordnet based ontologies) to measure the similarity of the user profiles on
different social networks. We specifically focused on Twitter and LinkedIn. In
this paper, we present the analysis and results from applying automated
classifiers for disambiguating profiles belonging to the same user from
different social networks. UserID and Name were found to be the most
discriminative features for disambiguating user profiles. Using the most
promising set of features and similarity metrics, we achieved accuracy,
precision and recall of 98%, 99%, and 96%, respectively.


title:
Phase Diagram of a Spin-Orbit Coupled Fermi Gases in a Bilayer Optical
  Lattice

abstract:
  We investigate the stability of helical superfluid phase in a spin-orbit
coupled Fermi gas loaded in a bilayer optical lattice. The phase diagram of the
system is constructed in the mean field framework. We investigate the
topological properties of the superfluid phases by a nontrivial application of
the Fermi surface topological invariant to our time-reversal invariant system
with degeneracies on the Fermi surface. We find that there is a first-order
phase boundary in the phase diagram of half filling case and the superfluid
phases are all topological trivial. The superfluid phase is topological
nontrivial when the filling fraction deviates from the half filling. In the
topological nontrivial superfluid phase, a full pairing gap exists in the bulk
and gapless helical Majorana edge states exist at the boundary.


title:
Measurement of hard double-parton interactions in W->lv+ 2 jet events at
  sqrt(s)=7 TeV with the ATLAS detector

abstract:
  The production of W bosons in association with two jets in proton-proton
collisions at a centre-of-mass energy of sqrt(s)=7 TeV has been analysed for
the presence of double-parton interactions using data corresponding to an
integrated luminosity of 36/pb, collected with the ATLAS detector at the LHC.
The fraction of events arising from double-parton interactions, fDP(D) has been
measured through the momentum balance between the two jets and amounts to
fDP(D) = 0.08 +- 0.01 (stat.) +- 0.02 (sys) for jets with transverse momentum
PT > 20 GeV and rapidity |y|<2.8. This corresponds to a measurement of the
effective area parameter for hard double-parton interactions of \sigma_eff = 15
+- 3 (stat.) +5 -3 (sys.) mb.


title: AGN astrophysics from comparing radio and Gaia optical astrometry

abstract:
  Gaia will open up a huge volume of new parameter space in which to explore
the physics of AGN and black hole evolution. We address the question as to how
far along the relativistic jets blazar radio, optical and gamma ray emission
originated. In some models the optical centroid wander should be detectable as
the relative contributions of thermal and non-thermal optical emission change.
Black holes powering AGN do not necessarily reside at the centres of their host
galaxies; they can be one member of a binary pair or they could have received a
kick after binary coalescence. For radio-loud AGN comparison of astrometric
radio and and optical positions can reveal such displacements. It is suggested
that it would be feasible to do this using Gaia and e-MERLIN for a sample of
thousands of elliptical radio galaxies.


title: On local property of absolute summability of factored Fourier series

abstract:
  We establish two general theorems on the local properties of the absolute
summability of factored Fourier series by applying a recently defined absolute
summability, $\left\vert A,\alpha_{n}\right\vert _{k}$ summability, and the
class $\mathcal{S}\left( \alpha_{n},\phi_{n}\right) $, which generalize some
well known results and can be applied to improve many classical absolute
summability methods.


title:
Constructing supersingular elliptic curves with a given endomorphism
  ring

abstract:
  Let O be a maximal order in the quaternion algebra B_p over Q ramified at p
and infinity. The paper is about the computational problem: Construct a
supersingular elliptic curve E over F_p such that End(E) = O. We present an
algorithm that solves this problem by taking gcds of the reductions modulo p of
Hilbert class polynomials. New theoretical results are required to determine
the complexity of our algorithm. Our main result is that, under certain
conditions on a rank three sublattice O^T of O, the order O is effectively
characterized by the three successive minima and two other short vectors of
O^T. The desired conditions turn out to hold whenever the j-invariant j(E), of
the elliptic curve with End(E) = O, lies in F_p. We can then prove that our
algorithm terminates with running time O(p^{1+\epsilon}) under the
aforementioned conditions. As a further application we present an algorithm to
simultaneously match all maximal order types with their associated
j-invariants. Our algorithm has running time O(p^{2.5+\epsilon}) operations and
is more efficient than Cervino's algorithm for the same problem.


title:
The twofold debris disk around HD 113766 A - Warm and cold dust as seen
  with VLTI/Midi and Herschel/Pacs

abstract:
  Warm debris disks are a sub-sample of the large population of debris disks,
and display excess emission in the mid-IR. Around solar-type stars, very few
objects show emission features in mid-IR spectroscopic observations, that are
attributed to small, warm silicate dust grains. The origin of this warm dust
can possibly be explained either by a collision between several bodies or by
transport from an outer belt. We present and analyse new far-IR Herschel/Pacs
observations, supplemented by ground-based data in the mid-IR (VLTI/Midi and
VLT/Visir), for one of these rare systems: the 10-16 Myr old debris disk around
HD 113766 A. We improve an existing model to account for these new
observations, and better constrain the spatial distribution of the dust and its
composition. We underline the limitations of SED modelling and the need for
spatially resolved observations. We find that the system is best described by
an inner disk located within the first AU, well constrained by the Midi data,
and an outer disk located between 9-13 AU. In the inner dust belt, our previous
finding of Fe-rich crystalline olivine grains still holds. We do not observe
time variability of the emission features over at least a 8 years time span, in
a environment subjected to strong radiation pressure. The time stability of the
emission features indicates that {\mu}m-sized dust grains are constantly
replenished from the same reservoir, with a possible depletion of
sub-{\mu}m-sized grains. We suggest that the emission features may arise from
multi-composition aggregates. We discuss possible scenarios concerning the
origin of the warm dust. The compactness of the innermost regions as probed by
Midi, as well as the dust composition, suggest that we are witnessing the
outcomes of (at least) one collision between partially differentiated bodies,
in an environment possibly rendered unstable by terrestrial planetary
formation.


title: Polarisation studies in H-t production

abstract:
  We summarise a recent study looking at top quark polarisation effects in
charged Higgs boson production. Lab frame angular and energy observables
relating to leptonic decays of top quarks are analysed, and corresponding
asymmetry parameters obtained. These are shown to be sensitive to top
polarisation and robust with respect to higher order corrections. Thus, they
are an efficient probe of charged Higgs parameter space.


title: Modified-gravity wormholes without exotic matter

abstract:
  A fundamental ingredient in wormhole physics is the flaring-out condition at
the throat which, in classical general relativity, entails the violation of the
null energy condition. In this work, we present the most general conditions in
the context of modified gravity, in which the matter threading the wormhole
throat satisfies all of the energy conditions, and it is the higher order
curvature terms, which may be interpreted as a gravitational fluid, that
support these nonstandard wormhole geometries. Thus, we explicitly show that
wormhole geometries can be theoretically constructed without the presence of
exotic matter, but are sustained in the context of modified gravity.


title: A Unified Software Framework for Empirical Gramians

abstract:
  A common approach in model reduction is balanced truncation, which is based
on gramian matrices classifiying certain attributes of states or parameters of
a given dynamic system. Initially restricted to linear systems, the empirical
gramians not only extended this concept to nonlinear systems, but also provide
a uniform computational method. This work introduces a unified software
framework supplying routines for six types of empirical gramians. The gramian
types will be discussed and applied in a model reduction framework for
multiple-input-multiple-output (MIMO) systems.


title:
Adaptive Continuous Homodyne Phase Estimation Using Robust
  Fixed-Interval Smoothing

abstract:
  Adaptive homodyne estimation of a continuously evolving optical phase using
time-symmetric quantum smoothing has been demonstrated experimentally to
provide superior accuracy in the phase estimate compared to adaptive or
nonadaptive estimation using filtering alone. Here, we illustrate how the
mean-square error in the adaptive phase estimate may be further reduced below
the standard quantum limit for the stochastic noise process considered by using
a Rauch-Tung-Striebel smoother as the estimator, alongwith an optimal Kalman
filter in the feedback loop. Further, the estimation using smoothing can be
made robust to uncertainties in the underlying parameters of the noise process
modulating the system phase to be estimated. This has been done using a robust
fixed-interval smoother designed for uncertain systems satisfying a certain
integral quadratic constraint.


title: Stratified precessional flow in spherical geometry

abstract:
  We investigate numerically in spherical geometry the interaction of
stratification with precession. Both stable stratification and unstable
stratification are studied. In the parameter regime we are concerned with,
stable stratification suppresses the precessional instability, whereas unstable
stratification and precession can either stablise or destablise each other at
the different precession rates.


title: Even-odd parity effects in Majorana junctions

abstract:
  We study a general Majorana junction, where N helical nanowires are connected
to a common s-wave superconductor proximity-inducing Majorana bound states in
the wires. The normal part of each wire (j=1,...,N) acts as connected lead,
where electrons can tunnel into the respective Majorana state \gamma_{A,j}. The
Majorana states at the other end, \gamma_{B,j}, are coupled to each other by an
arbitrary tunnel matrix. We examine the conditions for even-odd parity effects
in the tunnel conductance for various junction topologies.


title: On Nuclearity of $C^*$-algebras of Fell bundles over \'etale groupoids

abstract:
  In this paper, we show that if E is a Fell bundle over an amenable \'etale
locally compact Hausdorff groupoid such that every fiber on the unit space is
nuclear, then $C?^*r(E)$ is also nuclear. In order to show this result, we
introduce (minimal) tensor products of Fell bundles with fixed $C^*$-algebras.


title:
A Detailed Study of the Radio--FIR Correlation in NGC6946 with
  Herschel-PACS/SPIRE from KINGFISH

abstract:
  We derive the distribution of the synchrotron spectral index across NGC6946
and investigate the correlation between the radio continuum (synchrotron) and
far-infrared (FIR) emission using the KINGFISH Herschel PACS and SPIRE data.
The radio--FIR correlation is studied as a function of star formation rate,
magnetic field strength, radiation field strength, and the total gas surface
brightness. The synchrotron emission follows both star-forming regions and the
so-called magnetic arms present in the inter-arm regions. The synchrotron
spectral index is steepest along the magnetic arms ($\alpha_n \sim 1$), while
it is flat in places of giant H{\sc ii} regions and in the center of the galaxy
($\alpha_n \sim 0.6-0.7$). The map of $\alpha_n$ provides an observational
evidence for aging and energy loss of cosmic ray electrons propagating in the
disk of the galaxy. Variations in the synchrotron--FIR correlation across the
galaxy are shown to be a function of both star formation and magnetic fields.
We find that the synchrotron emission correlates better with cold rather than
with warm dust emission, when the interstellar radiation field is the main
heating source of dust. The synchrotron--FIR correlation suggests a coupling
between the magnetic field and the gas density. NGC6946 shows a power-law
behavior between the total (turbulent) magnetic field strength B and the star
formation rate surface density $\Sigma_{\rm SFR}$ with an index of
0.14\,(0.16)$\pm$0.01. This indicates an efficient production of the turbulent
magnetic field with the increasing gas turbulence expected in actively star
forming regions. The scale-by-scale analysis of the synchrotron--FIR
correlation indicates that the ISM affects the propagation of old/diffused
cosmic ray electrons, resulting in a diffusion coefficient of $D_0=4.6\times
10^{28}$\,cm$^2$\,s$^{-1}$ for 2.2\,GeV CREs.


title: Autoresonant soliton and decay pumping

abstract:
  The primary resonance equation in partial derivatives with external force and
slowly varying frequency is derived. The leading-order term of asymptotic
solution is constructed as a soliton with growing amplitude when time is large.
This growing solution is obtained due to the decaying amplitude of the external
force. A necessary condition for the growth of the solution in dissipative
media is obtained also.


title: Quasi-finite modules and asymptotic prime divisors

abstract:
  Let $A$ be a Noetherian ring, $J\subseteq A$ an ideal and $C$ a finitely
generated $A$-module. In this note we would like to prove the following
statement. Let $\{I_n\}_{n\geq 0}$ be a collection of ideals satisfying : (i)
$I_n\supseteq J^n$, for all $n$, (ii) $J^s\cdot I_s \subseteq I_{r+s}$, for all
$r,s\geq 0$ and (iii) $I_n\subseteq I_m$, whenever $m\leq n$. Then
$\Ass_A(I_nC/J^nC)$ is independent of $n$, for $n$ sufficiently large. Note
that the set of prime ideals $\cup_{n\geq 1} \Ass_A(I_nC/J^nC)$ is finite, so
the issue at hand is the realization that the primes in $\Ass_A(I_nC/J^nC)$
\textit{do not} behave periodically, as one might have expected, say if
$\bigoplus _{n\geq 0}I_n$ were a Noetherian $A$-algebra generated in degrees
greater than one. We also give a multigraded version of our results.


title: New insights into soft gluons and gravitons

abstract:
  The study of gluon radiation in QCD, in the limit of small ("soft") momentum,
remains an active research area, with a variety of phenomenological and
theoretical applications. Soft gluon emission leads to large logarithms in
perturbation theory which have to be summed up to all orders in the coupling,
and also governs the structure of infrared singularities. Recently, new
techniques and mathematical structures have been discovered, which enhance our
understanding of these all-order properties. This contribution will review a
number of key topics, including the relationship between QCD and gravity.


title:
Ultrafast filling of an electronic pseudogap in an incommensurate
  crystal

abstract:
  We investigate the quasiperiodic crystal (LaS)1.196(VS2) by angle and time
resolved photoemission spectroscopy. The dispersion of electronic states is in
qualitative agreement with band structure calculated for the VS2 slab without
the incommensurate distortion. Nonetheless, the spectra display a temperature
dependent pseudogap instead of quasiparticles crossing. The sudden
photoexcitation at 50 K induces a partial filling of the electronic pseudogap
within less than 80 fs. The electronic energy flows into the lattice modes on a
comparable timescale. We attribute this surprisingly short timescale to a very
strong electron-phonon coupling to the incommensurate distortion. This result
sheds light on the electronic localization arising in aperiodic structures and
quasicrystals.


title:
Abundance theorem for semi log canonical surfaces in positive
  characteristic

abstract:
  We prove the abundance theorem for semi log canonical surfaces in positive
characteristic.


title:
Tight closure with respect to a multiplicatively closed subset of an
  $F$-pure local ring

abstract:
  Let $R$ be a (commutative Noetherian) local ring of prime characteristic that
is $F$-pure. This paper studies a certain finite set ${\mathcal I}$ of radical
ideals of $R$ that is naturally defined by the injective envelope of the simple
$R$-module. This set ${\mathcal I}$ contains $0$ and $R$, and is closed under
taking primary components. For a multiplicatively closed subset $S$ of $R$, the
concept of tight closure with respect to $S$, or $S$-tight closure, is
discussed, together with associated concepts of $S$-test element and $S$-test
ideal. It is shown that an ideal of $R$ belongs to ${\mathcal I}$ if and only
if it is the $S'$-test ideal of $R$ for some multiplicatively closed subset
$S'$ of $R$. When $R$ is complete, ${\mathcal I}$ is also `closed under taking
test ideals', in the following sense: for each proper ideal $C$ in ${\mathcal
I}$, it turns out that $R/C$ is again $F$-pure, and if $J$ and $K$ are the
unique ideals of $R$ that contain $C$ and are such that $J/C$ is the (tight
closure) test ideal of $R/C$ and $K/C$ is the big test ideal of $R/C$, then
both $J$ and $K$ belong to ${\mathcal I}$. The paper ends with several
examples.


title:
Large temperature dependence of the number of carriers in Co-doped
  BaFe2As2

abstract:
  Using angle-resolved photoemission spectroscopy, we study the evolution of
the number of carriers in Ba(Fe(1-x)Cox)2As2 as a function of Co content and
temperature. We show that there is a k-dependent energy shift compared to
density functional calculations, which is large at low Co contents and low
temperatures and reduces the volume of hole and electron pockets by a factor 2.
This k-shift becomes negligible at high Co content and could be due to
interband charge or spin fluctuations. We further reveal that the bands shift
with temperature, changing significantly the number of carriers they contain
(up to 50%). We explain this evolution by thermal excitations of carriers among
the narrow bands, possibly combined with a temperature evolution of the
k-dependent fluctuations.


title:
Orbits and reversals of a drop rolling inside a horizontal circular
  hydraulic jump

abstract:
  We explore the complex dynamics of a non-coalescing drop of moderate size
inside a circular hydraulic jump of the same liquid formed on a horizontal
disk. In this situation the drop is moving along the jump and one observes two
different motions: a periodic one (it orbitates at constant speed) and an
irregular one involving reversals of the orbital motion. Modeling the drop as a
rigid sphere exchanging friction with liquid across a thin film of air, we
recover the orbital motion and the internal rotation of the drop. This internal
rotation is experimentally observed.


title:
Logarithmically Improved Blow-up Criteria for a Phase Field
  Navier-Stokes Vesicle-Fluid Interaction Model

abstract:
  In this paper, we study a hydrodynamical system modeling the deformation of
vesicle membrane under external incompressible viscous flow fields. The system
is in the Eulerian formulation and is governed by the coupling of the
incompressible Navier-Stokes equations with a phase field equation. In the
three dimensional case, we establish two logarithmically improved blow-up
criteria for local smooth solutions of this system in terms of the vorticity
field only in the homogeneous Besov spaces.


title: The role of van der Waals forces in water adsorption on metals

abstract:
  The interaction of water molecules with metal surfaces is typically weak and
as a result van der Waals (vdW) forces can be expected to be of importance.
Here we account for the systematic poor treatment of vdW forces in most popular
density functional theory (DFT) exchange-correlation functionals by applying
accurate non-local vdW density functionals. We have computed the adsorption of
a variety of exemplar systems including water monomer adsorption on Al(111),
Cu(111), Cu(110), Ru(0001), Rh(111), Pd(111), Ag(111), Pt(111), and
unreconstructed Au(111), and small clusters (up to 6 waters) on Cu(110). We
show that non-local correlations contribute substantially to the water-metal
bond in all systems, whilst water-water bonding is much less affected by
non-local correlations. Interestingly non-local correlations contribute more to
the adsorption of water on the reactive transition metal substrates than they
do on the noble metals. The relative stability, adsorption sites, and
adsorption geometries of competing water adstructures rarely differ when
comparing results obtained with semi-local functionals and the non-local vdW
density functionals, which explains the previous success of semi-local
functionals in characterizing adsorbed water structures on a number of metal
surfaces.


title: Generalized Parton Distributions of the Photon with Helicity Flip

abstract:
  We present a calculation of the generalized parton distributions (GPDs) of
the photon when the helicity of the initial photon is different from the final
photon. We calculate the GPDs using overlaps of photon light-front wave
functions (LFWFs) at leading order in electromagnetic coupling $\alpha$ and
zeroth order in the strong coupling $\alpha_s$, when the momentum transfer is
purely in the transverse direction. These involve a contribution of orbital
angular momentum of two units in the LFWFs. We express these GPDs in the impact
parameter space.


title: Laplacians on periodic discrete graphs

abstract:
  We consider Laplacians on $\Z^2$-periodic discrete graphs. The following
results are obtained: 1) The Floquet-Bloch decomposition is constructed and
basic properties are derived. 2) The estimates of the Lebesgue measure of the
spectrum in terms of geometric parameters of the graph are obtained. 3) The
spectrum of the Laplacian is described, when the so-called fundamental graph
consists of one or two vertices and any number of edges. 4) We consider the
hexagonal lattice perturbed by adding one edge to the fundamental graph. There
exist two cases: a) if the perturbed hexagonal lattice is bipartite, then the
spectrum of the perturbed Laplacian coincides with the spectrum $[-1,1]$ for
the unperturbed case, b) if the perturbed hexagonal lattice is not bipartite,
then there is a gap in the spectrum of the perturbed Laplacian. Moreover, some
deeper results are obtained for the perturbation of the square lattice.


title:
A pointwise characterization of functions of bounded variation on metric
  spaces

abstract:
  We give a new characterization of the space of functions of bounded variation
in terms of a pointwise inequality connected to the maximal function of a
measure. The characterization is new even in Euclidean spaces and it holds also
in general metric spaces.


title: Square Property, Equitable Partitions, and Product-like Graphs

abstract:
  Equivalence relations on the edge set of a graph $G$ that satisfy restrictive
conditions on chordless squares play a crucial role in the theory of Cartesian
graph products and graph bundles. We show here that such relations in a natural
way induce equitable partitions on the vertex set of $G$, which in turn give
rise to quotient graphs that can have a rich product structure even if $G$
itself is prime.


title: PhishAri: Automatic Realtime Phishing Detection on Twitter

abstract:
  With the advent of online social media, phishers have started using social
networks like Twitter, Facebook, and Foursquare to spread phishing scams.
Twitter is an immensely popular micro-blogging network where people post short
messages of 140 characters called tweets. It has over 100 million active users
who post about 200 million tweets everyday. Phishers have started using Twitter
as a medium to spread phishing because of this vast information dissemination.
Further, it is difficult to detect phishing on Twitter unlike emails because of
the quick spread of phishing links in the network, short size of the content,
and use of URL obfuscation to shorten the URL. Our technique, PhishAri, detects
phishing on Twitter in realtime. We use Twitter specific features along with
URL features to detect whether a tweet posted with a URL is phishing or not.
Some of the Twitter specific features we use are tweet content and its
characteristics like length, hashtags, and mentions. Other Twitter features
used are the characteristics of the Twitter user posting the tweet such as age
of the account, number of tweets, and the follower-followee ratio. These
Twitter specific features coupled with URL based features prove to be a strong
mechanism to detect phishing tweets. We use machine learning classification
techniques and detect phishing tweets with an accuracy of 92.52%. We have
deployed our system for end-users by providing an easy to use Chrome browser
extension which works in realtime and classifies a tweet as phishing or safe.
We show that we are able to detect phishing tweets at zero hour with high
accuracy which is much faster than public blacklists and as well as Twitter's
own defense mechanism to detect malicious content. To the best of our
knowledge, this is the first realtime, comprehensive and usable system to
detect phishing on Twitter.


title: Not all paths lead to Rome: Analysing the network of sister cities

abstract:
  This work analyses the practice of sister city pairing. We investigate
structural properties of the resulting city and country networks and present
rankings of the most central nodes in these networks. We identify different
country clusters and find that the practice of sister city pairing is not
influenced by geographical proximity but results in highly assortative
networks.