title:
Controlling Networks of Nonlinearly-Coupled Nodes using Response
  Surfaces

abstract:
  Control of complex processes is a major goal of network analyses. Most
approaches to control nonlinearly coupled systems require the network topology
and/or network dynamics. Unfortunately, neither the full set of participating
nodes nor the network topology is known for many important systems. On the
other hand, system responses to perturbations are often easily measured. We
show how the collection of such responses (a response surface) can be used for
network control. Analyses of model systems show that response surfaces are
smooth and hence can be approximated using low order polynomials. Importantly,
these approximations are largely insensitive to stochastic fluctuations in data
or measurement errors. They can be used to compute how a small set of nodes
need to be altered in order to direct the network close to a pre-specified
target state. These ideas, illustrated on a nonlinear electrical circuit, can
prove useful in many contexts including in reprogramming cellular states.


title:
Global existence for fully nonlinear reaction-diffusion systems
  describing multicomponent reactive flows

abstract:
  We consider combustion problems in the presence of complex chemistry and
nonlinear diffusion laws leading to fully nonlinear multispecies
reaction-diffusion equations. We establish results of existence of solution and
maximum principle, i.e. positivity of the mass fractions, which rely on
specific properties of the models. The nonlinear diffusion coefficients are
obtained by resolution of the so-called Stefan-Maxwell equations.


title:
Invariance of R-groups between p-adic inner forms of quasi-split
  classical groups

abstract:
  We study the reducibility of parabolically induced representations of
non-split inner forms of quasi-split classical groups. The isomorphism of
Arthur R-groups, endoscopic R-groups and Knapp-Stein R-groups is established,
as well as showing these R-groups are isomorphic to the corresponding ones for
the quasi-split form. This shows R-groups are an invariant of the L-packets.
The results are applied to classify the elliptic spectrum.


title: A Doubly Supersymmetric Particle in 3+3 Dimensions

abstract:
  It is shown how in 3+3 dimensions, it is possible to have a superparticle
Lagrangian that has manifest supersymmetry both on the world line and in the
target space.


title: A Sparse and Adaptive Prior for Time-Dependent Model Parameters

abstract:
  We consider the scenario where the parameters of a probabilistic model are
expected to vary over time. We construct a novel prior distribution that
promotes sparsity and adapts the strength of correlation between parameters at
successive timesteps, based on the data. We derive approximate variational
inference procedures for learning and prediction with this prior. We test the
approach on two tasks: forecasting financial quantities from relevant text, and
modeling language contingent on time-varying financial measurements.


title: Gamma-ray Burst Flares: X-ray Flaring. II

abstract:
  We present a catalog of 497 flaring periods found in gamma-ray burst (GRB)
light curves taken from the online XRT GRB Catalogue. We analyzed 680
individual light curves using a flare detection method developed and used on
our UV/optical GRB Flare Catalog. The method makes use of the Bayesian
Information Criterion to analyze the residuals of fitted GRB light curves and
statistically determines the optimal fit to the light curve residuals in
attempt to identify any additional features. These features, which we classify
as flares, are identified by iteratively adding additional `breaks' to the
light curve. We find evidence of flaring in 310 of the analyzed light curves.
For those light curves with flares, we find an average number of ~1.5 flares
per GRB. As with the UV/optical, flaring in our sample is generally confined to
the first 1000 s of the afterglow, but can be detected to beyond 10^5 s. Only
~50% of the detected flares follow the `classical' definition of \Delta t/t <<
1, with many of the largest flares exhibiting \Delta t/t ~ 1 and some exceeding
this value.


title:
Recurrent Solutions of Stochastic Differential Equations with
  Non-constant Diffusion Coefficients which obey the Law of the Iterated
  Logarithm

abstract:
  By using a change of scale and space, we study a class of stochastic
differential equations (SDEs) whose solutions are drift--perturbed and exhibit
behaviour analogous to standard Brownian motion including to the Law of the
Iterated Logarithm (LIL). Sufficient conditions ensuring that these processes
obey the LIL are given.


title: Undulatory swimming in fluids with polymer networks

abstract:
  The motility behavior of the nematode Caenorhabditis elegans in polymeric
solutions of varying concentrations is systematically investigated in
experiments using tracking and velocimetry methods. As the polymer
concentration is increased, the solution undergoes a transition from the
semi-dilute to the concentrated regime, where these rod-like polymers entangle,
align, and form networks. Remarkably, we find an enhancement in the nematode's
swimming speed of approximately 65% in concentrated solutions compared to
semi-dilute solutions. Using velocimetry methods, we show that the undulatory
swimming motion of the nematode induces an anisotropic mechanical response in
the fluid. This anisotropy, which arises from the fluid micro-structure, is
responsible for the observed increase in swimming speed.


title: Saturation of Concurrent Collapsible Pushdown Systems

abstract:
  Multi-stack pushdown systems are a well-studied model of concurrent
computation using threads with first-order procedure calls. While, in general,
reachability is undecidable, there are numerous restrictions on stack behaviour
that lead to decidability. To model higher-order procedures calls, a
generalisation of pushdown stacks called collapsible pushdown stacks are
required. Reachability problems for multi-stack collapsible pushdown systems
have been little studied. Here, we study ordered, phase-bounded and
scope-bounded multi-stack collapsible pushdown systems using saturation
techniques, showing decidability of control state reachability and giving a
regular representation of all configurations that can reach a given control
state.


title: Bilinear Generalized Approximate Message Passing

abstract:
  We extend the generalized approximate message passing (G-AMP) approach,
originally proposed for high-dimensional generalized-linear regression in the
context of compressive sensing, to the generalized-bilinear case, which enables
its application to matrix completion, robust PCA, dictionary learning, and
related matrix-factorization problems. In the first part of the paper, we
derive our Bilinear G-AMP (BiG-AMP) algorithm as an approximation of the
sum-product belief propagation algorithm in the high-dimensional limit, where
central-limit theorem arguments and Taylor-series approximations apply, and
under the assumption of statistically independent matrix entries with known
priors. In addition, we propose an adaptive damping mechanism that aids
convergence under finite problem sizes, an expectation-maximization (EM)-based
method to automatically tune the parameters of the assumed priors, and two
rank-selection strategies. In the second part of the paper, we discuss the
specializations of EM-BiG-AMP to the problems of matrix completion, robust PCA,
and dictionary learning, and present the results of an extensive empirical
study comparing EM-BiG-AMP to state-of-the-art algorithms on each problem. Our
numerical results, using both synthetic and real-world datasets, demonstrate
that EM-BiG-AMP yields excellent reconstruction accuracy (often best in class)
while maintaining competitive runtimes and avoiding the need to tune
algorithmic parameters.


title:
An Extremely Luminous and Variable Ultraluminous X-ray Source in the
  Outskirts of Circinus Observed with NuSTAR

abstract:
  Following a serendipitous detection with the NuSTAR observatory, we present a
multi-epoch spectral and temporal analysis of an extreme ultraluminous X-ray
source (ULX) located in the outskirts of the Circinus galaxy, hereafter
Circinus ULX5, including coordinated follow-up observations with XMM-Newton and
NuSTAR. The NuSTAR data presented here represent one of the first instances of
a ULX reliably detected at hard (E>10 keV) X-rays. Circinus ULX5 is variable on
long timescales by at least a factor of ~5 in flux, and was caught in a
historically bright state during our 2013 observations (0.3-30.0 keV luminosity
of 1.6e40 erg/s). During this epoch, the source displayed a curved 3-10 keV
spectrum, broadly similar to other bright ULXs. While in many cases the
interpretation of spectral components in ULXs is uncertain, the spectral and
temporal properties of the all the high quality datasets currently available
strongly support a simple disk-corona model reminiscent of that invoked for
Galactic binaries, with the accretion disk becoming more prominent as the
luminosity increases. However, although the disk temperature and luminosity are
remarkably well correlated across all timescales currently probed, the observed
luminosity follows T^(1.70+/-0.17), flatter than that expected for simple
blackbody radiation. The spectral variability displayed by Circinus ULX5 is
highly reminiscent of that observed from some known Galactic black hole
binaries (BHBs) at high luminosities. This comparison would imply a black hole
mass of ~90 Msun for Circinus ULX5. However, given the diverse behavior
observed from Galactic BHB accretion disks, this mass estimate is still
uncertain. Finally, the limits placed on any undetected iron absorption
features with the 2013 dataset imply that we are not viewing the central
regions of Circinus ULX5 through any extreme super-Eddington outflow.
[abridged]


title:
Growing dust grains in protoplanetary discs - I. Radial drift with toy
  growth models

abstract:
  In a series of papers, we present a comprehensive analytic study of the
global motion of growing dust grains in protoplanetary discs, addressing both
the radial drift and the vertical settling of the particles. Here we study how
the radial drift of dust particles is affected by grain growth. In a first
step, toy models in which grain growth can either be constant, accelerate or
decelerate are introduced. The equations of motion are analytically integrable
and therefore the grains dynamics is easy to understand.
  The radial motion of growing grains is governed by the relative efficiency of
the growth and migration processes which is expressed by the dimensionless
parameter Lambda, as well as the exponents for the gas surface density and
temperature profiles, denoted p and q respectively. When Lambda is of order
unity, growth and migration are strongly coupled, providing the most efficient
radial drift. For the toy models considered, grains pile up when -p+q+1/2<0.
Importantly, we show the existence of a second process which can help discs to
retain their solid materials. For accelerating growth, grains end up their
migration at a finite radius, thus avoiding being accreted onto the central
star.


title: Bubble visualization in a simulated hydraulic jump

abstract:
  This is a fluid dynamics video of two- and three-dimensional computational
fluid dynamics simulations carried out at St. Anthony Falls Laboratory. A
transient hydraulic jump is simulated using OpenFOAM, an open source numerical
solver. A Volume of Fluid numerical method is employed with a realizable
k-epsilon turbulence model. The goal of this research is to model the void
fraction and bubble size in a transient hydraulic jump. This fluid dynamics
video depicts the air entrainment characteristics and bubble behavior within a
hydraulic jump of Froude number 4.82.


title: The small-world effect is a modern phenomenon

abstract:
  The "small-world effect" is the observation that one can find a short chain
of acquaintances, often of no more than a handful of individuals, connecting
almost any two people on the planet. It is often expressed in the language of
networks, where it is equivalent to the statement that most pairs of
individuals are connected by a short path through the acquaintance network.
Although the small-world effect is well-established empirically for
contemporary social networks, we argue here that it is a relatively recent
phenomenon, arising only in the last few hundred years: for most of mankind's
tenure on Earth the social world was large, with most pairs of individuals
connected by relatively long chains of acquaintances, if at all. Our
conclusions are based on observations about the spread of diseases, which
travel over contact networks between individuals and whose dynamics can give us
clues to the structure of those networks even when direct network measurements
are not available. As an example we consider the spread of the Black Death in
14th-century Europe, which is known to have traveled across the continent in
well-defined waves of infection over the course of several years. Using
established epidemiological models, we show that such wave-like behavior can
occur only if contacts between individuals living far apart are exponentially
rare. We further show that if long-distance contacts are exponentially rare,
then the shortest chain of contacts between distant individuals is on average a
long one. The observation of the wave-like spread of a disease like the Black
Death thus implies a network without the small-world effect.


title:
Growing dust grains in protoplanetary discs - II. The Radial drift
  barrier problem

abstract:
  We aim to study the migration of growing dust grains in protoplanetary discs,
where growth and migration are tightly coupled. This includes the crucial issue
of the radial-drift barrier for growing dust grains. We therefore extend the
study performed in Paper I, considering models for grain growth and grain
dynamics where both the migration and growth rate depend on the grain size and
the location in the disc. The parameter space of disc profiles and growth
models is exhaustively explored. In doing so, interpretations for the grain
motion found in numerical simulations are also provided.
  We find that a large number of cases is required to characterise entirely the
grains radial motion, providing a large number of possible outcomes. Some of
them lead dust particles to be accreted onto the central star and some of them
don't.
  We find then that q<1 is required for discs to retain their growing
particles, where q is the exponent of the radial temperature profile T(R)
proportional to R^-q. Additionally, the initial dust-to gas ratio has to exceed
a critical value for grains to pile up efficiently, thus avoiding being
accreted onto the central star. Discs are also found to retain efficiently
small dust grains regenerated by fragmentation. We show how those results are
sensitive to the turbulent model considered.
  Even though some physical processes have been neglected, this study allows to
sketch a scenario in which grains can survive the radial-drift barrier in
protoplanetary discs as they grow.


title: Growing dust grains in protoplanetary discs - III. Vertical settling

abstract:
  We aim to derive a simple analytic model to understand the essential
properties of vertically settling growing dust grains in laminar protoplanetary
discs. Separating the vertical dynamics from the motion in the disc midplane,
we integrate the equations of motion for both a linear and an exponential grain
growth rate. Numerical integrations are performed for more complex growth
models.
  We find that the settling efficiency depends on the value of the
dimensionless parameter gamma, which characterises the relative efficiency of
grain growth with respect to the gas drag. Since gamma is expected to be of
order as the initial dust-to-gas ratio in the disc (of order 10^-2), grain
growth enhances the energy dissipation of the dust particles and improve the
settling efficiency in protoplanetary discs. This behaviour is mostly
independent of the growth model considered as well as of the radial drift of
the particles.


title: Gauge optimization and duality

abstract:
  Gauge functions significantly generalize the notion of a norm, and gauge
optimization, as defined by Freund (1987}, seeks the element of a convex set
that is minimal with respect to a gauge function. This conceptually simple
problem can be used to model a remarkable array of useful problems, including a
special case of conic optimization, and related problems that arise in machine
learning and signal processing. The gauge structure of these problems allows
for a special kind of duality framework. This paper explores the duality
framework proposed by Freund, and proposes a particular form of the problem
that exposes some useful properties of the gauge optimization framework (such
as the variational properties of its value function), and yet maintains most of
the generality of the abstract form of gauge optimization.


title: Searching for IR excesses in Sun-like stars observed by WISE

abstract:
  We present the results of a search of infrared excess candidates in a
comprehensive (29\,000 stars) magnitude limited sample of dwarf stars, spanning
the spectral range F2-K0, and brighter than V$=$15 mag. We searched the sample
within the {\em WISE} all sky survey database for objects within 1 arcsecond of
the coordinates provided by SIMBAD database and found over 9\,000 sources
detected in all {\em WISE} bands. This latter sample excludes objects that are
flagged as extended sources and those images which are affected by various
optical artifacts. For each detected object, we compared the observed W4/W2
(22$\mu$m/4.6$\mu$m) flux ratio with the expected photospheric value and
identified 197 excess candidates at 3$\sigma$. For the vast majority of
candidates, the results of this analysis represent the first reported evidence
of an IR excess. Through the comparison with a simple black-body emission
model, we derive estimates of the dust temperature, as well as of the dust
fractional luminosities. For more than 80% of the sample this temperature is
higher than 120 K, suggesting the presence of warm circumstellar dust.
Complementary observations at longer wavelengths (far-IR and sub-mm) are
required for better characterising and explaining the origin of this emission.


title: Duality in Graphical Models

abstract:
  Graphical models have proven to be powerful tools for representing
high-dimensional systems of random variables. One example of such a model is
the undirected graph, in which lack of an edge represents conditional
independence between two random variables given the rest. Another example is
the bidirected graph, in which absence of edges encodes pairwise marginal
independence. Both of these classes of graphical models have been extensively
studied, and while they are considered to be dual to one another, except in a
few instances this duality has not been thoroughly investigated. In this paper,
we demonstrate how duality between undirected and bidirected models can be used
to transport results for one class of graphical models to the dual model in a
transparent manner. We proceed to apply this technique to extend previously
existing results as well as to prove new ones, in three important domains.
First, we discuss the pairwise and global Markov properties for undirected and
bidirected models, using the pseudographoid and reverse-pseudographoid rules
which are weaker conditions than the typically used intersection and
composition rules. Second, we investigate these pseudographoid and reverse
pseudographoid rules in the context of probability distributions, using the
concept of duality in the process. Duality allows us to quickly relate them to
the more familiar intersection and composition properties. Third and finally,
we apply the dualization method to understand the implications of faithfulness,
which in turn leads to a more general form of an existing result.


title: KOI-152's Low Density Planets

abstract:
  KOI-152 is among the first known systems of multiple transiting planetary
candidates (Steffen et al. 2010) ranging in size from 3.5 to 7 times the size
of the Earth, in a compact configuration with orbital periods near a 1:2:4:6
chain of commensurability, from 13.5 days to 81.1 days. All four planets
exhibit transit timing variations with periods that are consistent with the
distance of each planet to resonance with its neighbors. We perform a dynamical
analysis of the system based on transit timing measurements over 1282 days of
\textit{Kepler} photometry. Stellar parameters are obtained with a combination
of spectral classification and the stellar density constraints provided by
light curve analysis and orbital eccentricity solutions from our dynamical
study. Our models provide tight constraints on the masses of all four
transiting bodies, demonstrating that they are planets and that they orbit the
same star. All four of KOI-152's transiting planets have low densities given
their sizes, consistent with other studies of compact multiplanet transiting
systems. The largest of the four, KOI-152.01, has the lowest bulk density yet
determined amongst sub-Saturn mass planets.


title:
Energetics of vacancy segregation to symmetric tilt grain boundaries in
  HCP materials

abstract:
  Molecular static simulations of 190 symmetric tilt grain boundaries in HCP
metals were used to understand the energetics of vacancy segregation, which is
important for designing stable interfaces in harsh environments. Simulation
results show that the local arrangements of grain boundaries and the resulting
structural units have a significant influence on the magnitude of vacancy
binding energies, and the site-to-site variation within each boundary is
substantial. Comparing the vacancy binding energies for each site in different
c/a ratio materials shows that the binding energy increases significantly with
an increase in c/a ratio. For example, in the [1-210] tilt axis, Ti and Zr with
c/a=1.5811 have a lower vacancy binding energy than the Mg with c/a=1.6299.
Furthermore, when the grain boundary energies of all 190 boundaries in all
three elements are plotted against the vacancy binding energies of the same
boundaries, a highly negative correlation (r = -0.7144) is revealed that has a
linear fit with a proportionality constant of -25 ang^2. This is significant
for applications where extreme environmental damage generates lattice defects
and grain boundaries act as sinks for both vacancies and interstitial atoms.


title: Measuring Berry curvature with quantum Monte Carlo

abstract:
  The Berry curvature and its descendant, the Berry phase, play an important
role in quantum mechanics. They can be used to understand the Aharonov-Bohm
effect, define topological Chern numbers, and generally to investigate the
geometric properties of a quantum ground state manifold. While Berry curvature
has been well-studied in the regimes of few-body physics and non-interacting
particles, its use in the regime of strong interactions is hindered by the lack
of numerical methods to solve it. In this paper we fill this gap by
implementing a quantum Monte Carlo method to solve for the Berry curvature,
based on interpreting Berry curvature as a leading correction to imaginary time
ramps. We demonstrate our algorithm using the transverse-field Ising model in
one and two dimensions, the latter of which is non-integrable. Despite the fact
that the Berry curvature gives information about the phase of the wave
function, we show that our algorithm has no sign or phase problem for standard
sign-problem-free Hamiltonians. Our algorithm scales similarly to conventional
methods as a function of system size and energy gap, and therefore should prove
a valuable tool in investigating the quantum geometry of many-body systems.


title:
Quantum oscillations in non-Fermi liquids: Implications for
  high-temperature superconductors

abstract:
  We address quantum oscillation experiments in high Tc superconductors and the
evidence from these experiments for a pseudogap versus a Fermi liquid phase at
high magnetic fields. As a concrete alternative to a Fermi liquid phase, the
pseudogap state we consider derives from earlier work within a Gor'kov-based
Landau level approach. Here the normal state pairing gap in the presence of
high fields is spatially non-uniform, incorporating small gap values. These, in
addition to d-wave gap nodes, are responsible for the persistence of quantum
oscillations. Important here are methodologies for distinguishing different
scenarios. To this end we examine the temperature dependence of the
oscillations. Detailed quantitative analysis of this temperature dependence
demonstrates that a high field pseudogap state in the cuprates may well
"masquerade" as a Fermi liquid.


title: Localized Iterative Methods for Interpolation in Graph Structured Data

abstract:
  In this paper, we present two localized graph filtering based methods for
interpolating graph signals defined on the vertices of arbitrary graphs from
only a partial set of samples. The first method is an extension of previous
work on reconstructing bandlimited graph signals from partially observed
samples. The iterative graph filtering approach very closely approximates the
solution proposed in the that work, while being computationally more efficient.
As an alternative, we propose a regularization based framework in which we
define the cost of reconstruction to be a combination of smoothness of the
graph signal and the reconstruction error with respect to the known samples,
and find solutions that minimize this cost. We provide both a closed form
solution and a computationally efficient iterative solution of the optimization
problem. The experimental results on the recommendation system datasets
demonstrate effectiveness of the proposed methods.


title:
Mechanism for enhancement of superconductivity in multi-band systems
  with odd parity hybridization

abstract:
  The study of multi-band superconductivity is relevant for a variety of
systems, from ultra cold atoms with population imbalance to particle physics,
and condensed matter. As a consequence, this problem has been widely
investigated bringing to light many new and interesting phenomena. In this work
we point out and explore a correspondence between a two-band metal with a
$k$-dependent hybridization and a uniformly polarized fermionic system in the
presence of spin-orbit coupling (SOC). We study the ground state phase diagram
of the metal in the presence of an attractive interaction. We find remarkable
superconducting properties whenever hybridization mixes orbitals of different
parities in neighboring sites. We show that this mechanism enhances
superconductivity and drives the crossover from weak to strong coupling in
analogy with SOC in cold atoms. We obtain the quantum phase transitions between
the normal and superfluid states, as the intensity of different parameters
characterizing the metal are varied, including Lifshitz transitions, with no
symmetry breaking, associated with the appearance of soft modes in the Fermi
surface.


title: A Lyapunov Optimization Approach to Repeated Stochastic Games

abstract:
  This paper considers a time-varying game with $N$ players. Every time slot,
players observe their own random events and then take a control action. The
events and control actions affect the individual utilities earned by each
player. The goal is to maximize a concave function of time average utilities
subject to equilibrium constraints. Specifically, participating players are
provided access to a common source of randomness from which they can optimally
correlate their decisions. The equilibrium constraints incentivize
participation by ensuring that players cannot earn more utility if they choose
not to participate. This form of equilibrium is similar to the notions of Nash
equilibrium and correlated equilibrium, but is simpler to attain. A Lyapunov
method is developed that solves the problem in an online \emph{max-weight}
fashion by selecting actions based on a set of time-varying weights. The
algorithm does not require knowledge of the event probabilities and has
polynomial convergence time. A similar method can be used to compute a standard
correlated equilibrium, albeit with increased complexity.


title:
High Performance Photocathodes based on Molecular Beam Epitaxy
  Deposition for Next Generation Photo Detectors and Light Sources

abstract:
  The development of high-performance photocathodes is a key challenge for
future accelerator and particle physics applications. In this paper
photocathode growth through molecular beam epitaxy is introduced as a promising
technique to obtain robust, highly efficient alkali-antimonide based
photocathodes. Recent research shows that the quantum efficiency of
photocathodes can be significantly enhanced through control of the photocathode
crystallinity. Molecular beam epitaxy allows for cost-effective growth of
large-area photocathodes with excellent control of the stoichiometry and
crystallinity, making photocathodes with peak quantum efficiencies exceeding
35% routine.


title:
Symmetry Analysis in Linear Hydrodynamic Stability Theory: Classical and
  New Modes in Linear Shear

abstract:
  We present a symmetry classification of the linearised Navier-Stokes
equations for a two-dimensional unbounded linear shear flow of an
incompressible fluid. The full set of symmetries is employed to systematically
derive invariant ansatz functions. The symmetry analysis grasps three
approaches. Two of them are existing ones, representing the classical normal
modes and the Kelvin modes, while the third is a novel approach and leads to a
new closed-form solution of traveling modes, showing qualitatively different
behaviour in energetics, shape and kinematics when compared to the classical
approaches. The last modes are energy conserving in the inviscid case. They are
localized in the cross-stream direction and periodic in the streamwise
direction. As for the kinematics, they travel at constant velocity in the
cross-stream direction, whilst in the streamwise direction they are accelerated
by the base flow. In the viscous case, the modes break down due to damping of
high wavenumber contributions.


title: Explanation and Prediction of Observables using Continuum Strong QCD

abstract:
  The last five years have brought considerable progress in the study of the
bound-state problem in continuum quantum field theory. We highlight a subset of
that progress; viz., that made within the context of Dyson Schwinger equation
analyses of cold, sparse hadrons. Our focus is primarily on advances in the
reliable computation, explanation and prediction of quantities that are truly
measurable; but we also review aspects of a new paradigm that has condensates
contained within hadrons, and explain that the asymptotic form of parton
distribution amplitudes and functions are practically unreachable with
terrestrial facilities. Given the pace of expansion in experiment and
improvement in theory, it appears possible that the next five years will bring
profound growth in our store of knowledge about hadrons and nuclei.


title: Umbilical surfaces of products of space forms

abstract:
  We give a complete classification of umbilical surfaces of arbitrary
codimension of a product $Q^{n_1}_{k_1}\times Q^{n_2}_{k_2}$ of space forms
whose curvatures satisfy $k_1 + k_2 \not= 0$.


title: Single-Walled Carbon Nanotube Sample Purification

abstract:
  Removal of impurities and aggregates from as-grown single walled-carbon
nanotube (SWCNT) materials remains an important challenge in nanotube research
and applications. We report a simple but effective purification method that
uses permanent magnets to remove nanotube aggregates, as well as residual
metallic catalyst, from surfactant-coated aqueous SWCNT suspensions. Samples
have been characterized by optical absorption, fluorescence and Raman
spectroscopies; AFM and near-IR fluorescence microscopies; and TGA. We found
that magnetic purification gives samples with reduced absorption backgrounds
and high fluorescence efficiencies comparable to those prepared by
ultracentrifugation. Nanotubes in magnetically processed HiPco samples are at
least 80% individualized. We propose that SWCNT aggregates are preferentially
removed because they contain disproportionate amounts of ferromagnetic catalyst
particles. As compared to ultracentrifugation, magnetic processing offers major
advantages in cost, simplicity, energy consumption, and scalability.


title: Using Fast Photosensors in Water Cherenkov Neutrino Detectors

abstract:
  Many of the yet unanswered questions in neutrino physics, such as CP
violation in the lepton sector or neutrino mass hierarchy, could be answered
with higher sensitivity neutrino experiments. New photodetectors based on
micro-channel plates are being developed by the Large-Area Picosecond Photo
Detector (LAPPD) Collaboration. These photosensors have been shown to have
excellent spatial and timing resolution. Using these devices in massive water
Cherenkov detectors, we could significantly improve the vertex resolution for
neutrinos enhancing background rejection for neutrino oscillation experiments.
We present preliminary results on the reconstruction capabilities for single
particles in water Cherenkov detectors using fast photosensors.


title:
Star formation histories, extinction, and dust properties of strongly
  lensed z~1.5-3 star-forming galaxies from the Herschel Lensing Survey

abstract:
  Multi-wavelength, optical to IR/sub-mm observations of 5 strongly lensed
galaxies identified by the Herschel Lensing Survey, plus two well-studied
lensed galaxies, MS1512-cB58 and the Cosmic Eye, for which we also provide
updated Herschel measurements, are used to determine the physical properties of
z~1.5-3 star-forming galaxies close to or below the detection limits of blank
fields. We constrain their stellar and dust content, determine star formation
rates and histories, dust attenuation and extinction laws, and other related
properties. We perform SED-fits of the full photometry of each object as well
for the optical and infrared parts separately, exploring various parameters,
including nebular emission. The IR observations and emission line measurements,
where available, are used a posteriori constraints on the models. Besides the
various stellar population models we explore, we use the observed IR/UV ratio
to estimate the extinction and create "energy conserving models", that
constrain most accurately the physical properties of our sources. Our sample
has a median lensing-corrected IR luminosity ~ 3e11 Lsun, stellar masses
between 2e9 and 2e11 Msun, and IR/UV luminosity ratios spanning a wide range.
The dust masses of our galaxies are in the range 2 to 17e7 Msun, extending
previous studies at the same redshift down to lower masses. We do not find any
particular trend of the dust temperature Tdust with IR luminosity, suggesting
an overall warmer dust regime at our redshift regardless of luminosity. Lensing
enables us to study the detailed physical properties of individual IR-detected
z~1.5-3 galaxies up to a factor ~10 fainter than achieved with deep blank field
observations. We demonstrate that multi-wavelength observations combining
stellar and dust emission can constrain star formation histories and extinction
laws of star-forming galaxies.


title:
A category of kernels for equivariant factorizations, II: further
  implications

abstract:
  We leverage the results of the prequel in combination with a theorem of D.
Orlov to yield some results in Hodge theory of derived categories of
factorizations and derived categories of coherent sheaves on varieties. In
particular, we provide a conjectural geometric framework to further understand
M. Kontsevich's Homological Mirror Symmetry conjecture. We obtain new cases of
a conjecture of Orlov concerning the Rouquier dimension of the bounded derived
category of coherent sheaves on a smooth variety. Further, we introduce actions
of $A$-graded commutative rings on triangulated categories and their associated
Noether-Lefschetz spectra as a new invariant of triangulated categories. They
are intended to encode information about algebraic classes in the cohomology of
an algebraic variety. We provide some examples to motivate the connection.


title: Bound state spectrum of the triplet states in the Be atom

abstract:
  The bound state spectrum of the low-lying triplet states in the Be atom is
investigated. In particular, we perform accurate computations of the bound
triplet $S$, $P$, $D$, $F$, $G$, $H$ and $I$ states in the Be atom. The results
of these calculations are employed to draw the spectral diagram which contains
the energy levels of the triplet states. Based on our computational results we
can observe transitions from the low-lying bound states to the weakly-bound
Rydberg states. For the $2^3S$, $3^3S$ and $4^3S$ states in the Be atom we also
determine a number of bound states properties.


title: Control of a lane-drop bottleneck through variable speed limits

abstract:
  In this study, we formulate the VSL control problem for the traffic system in
a zone upstream to a lane-drop bottleneck based on two traffic flow models: the
Lighthill-Whitham-Richards (LWR) model, which is an infinite-dimensional
partial differential equation, and the link queue model, which is a
finite-dimensional ordinary differential equation. In both models, the
discharging flow-rate is determined by a recently developed model of capacity
drop, and the upstream in-flux is regulated by the speed limit in the VSL zone.
Since the link queue model approximates the LWR model and is much simpler, we
first analyze the control problem and develop effective VSL strategies based on
the former. First for an open-loop control system with a constant speed limit,
we prove that a constant speed limit can introduce an uncongested equilibrium
state, in addition to a congested one with capacity drop, but the congested
equilibrium state is always exponentially stable. Then we apply a feedback
proportional-integral (PI) controller to form a closed-loop control system, in
which the congested equilibrium state and, therefore, capacity drop can be
removed by the I-controller. Both analytical and numerical results show that,
with appropriately chosen controller parameters, the closed-loop control system
is stable, effect, and robust. Finally, we show that the VSL strategies based
on I- and PI-controllers are also stable, effective, and robust for the LWR
model. Since the properties of the control system are transferable between the
two models, we establish a dual approach for studying the control problems of
nonlinear traffic flow systems. We also confirm that the VSL strategy is
effective only if capacity drop occurs. The obtained method and insights can be
useful for future studies on other traffic control methods and implementations
of VSL strategies.


title: Rotation Curve of the Milky Way out to $\sim$ 200 kpc

abstract:
  The rotation curve (RC) of our Galaxy, the Milky Way, is constructed starting
from its very inner regions (few hundred pc) out to a large Galactocentric
distance of $\sim 200$ kpc using kinematical data on a variety of tracer
objects moving in the gravitational potential of the Galaxy, without assuming
any theoretical models of the visible and dark matter components of the Galaxy.
We study the effect on the RC due to the uncertainties in the values of the
Galactic Constants (GCs) $R_\odot$ and $V_\odot$ (these being the sun's
distance from and circular rotation speed around the Galactic center,
respectively) and the velocity anisotropy parameter $\beta$ of the halo tracer
objects used for deriving the RC at large Galactocentric distances. The
resulting RC in the disk region is found to depend significantly on the choice
of the GCs, while the dominant uncertainty in the RC at large distances beyond
the stellar disk comes from the uncertainty in the value of $\beta$. In general
we find that the mean RC steadily declines at distances beyond $\sim 60$ kpc,
independently of the value of $\beta$. Also, at a given radius, the circular
speed is lower for larger values of $\beta$ (i.e., for more radially biased
velocity anisotropy). Considering that the largest possible value of $\beta$ is
unity, which corresponds to stellar orbits being purely radial, our results for
the case of $\beta=1$ give a lower limit to the total mass of the Galaxy within
$\sim 200$ kpc, $M(200 {\rm kpc}) \gsim (6.8\pm4.1) \times 10^{11} M_\odot$,
independently of any model of the dark matter halo of the Galaxy.


title: A kinematic wave theory of capacity drop

abstract:
  Capacity drop at active bottlenecks is one of the most puzzling traffic
phenomena, but a thorough understanding is practically important for designing
variable speed limit and ramp metering strategies. In this study, we attempt to
develop a simple model of capacity drop within the framework of kinematic wave
theory based on the observation that capacity drop occurs when an upstream
queue forms at an active bottleneck. In addition, we assume that the
fundamental diagrams are continuous in steady states. This assumption is
consistent with observations and can avoid unrealistic infinite characteristic
wave speeds in discontinuous fundamental diagrams. A core component of the new
model is an entropy condition defined by a discontinuous boundary flux
function. For a lane-drop area, we demonstrate that the model is well-defined,
and its Riemann problem can be uniquely solved. We theoretically discuss
traffic stability with this model subject to perturbations in density, upstream
demand, and downstream supply. We clarify that discontinuous flow-density
relations, or so-called "discontinuous" fundamental diagrams, are caused by
incomplete observations of traffic states. Theoretical results are consistent
with observations in the literature and are verified by numerical simulations
and empirical observations. We finally discuss potential applications and
future studies.


title: Foulkes modules and decomposition numbers of the symmetric group

abstract:
  The decomposition matrix of a finite group in prime characteristic p records
the multiplicities of its p-modular irreducible representations as composition
factors of the reductions modulo p of its irreducible representations in
characteristic zero. The main theorem of this paper gives a combinatorial
description of certain columns of the decomposition matrices of symmetric
groups in odd prime characteristic. The result applies to blocks of arbitrarily
high weight. It is obtained by studying the p-local structure of certain twists
of the permutation module given by the action of the symmetric group of even
degree 2m on the collection of set partitions of a set of size 2m into m sets
each of size two. In particular, the vertices of the indecomposable summands of
all such modules are characterized; these summands form a new family of
indecomposable p-permutation modules for the symmetric group. As a further
corollary it is shown that for every natural number w there is a diagonal
Cartan number in a block of the symmetric group of weight w equal to w+1.


title:
Influence of a local change of depth on the behavior of bouncing oil
  drops

abstract:
  The work of Couder \textit{et al} (see also Bush \textit{et al}) inspired
consideration of the impact of a submerged obstacle, providing a local change
of depth, on the behavior of oil drops in the bouncing regime. In the linked
videos, we recreate some of their results for a drop bouncing on a uniform
depth bath of the same liquid undergoing vertical oscillations just below the
conditions for Faraday instability, and show a range of new behaviors
associated with change of depth.
  This article accompanies a fluid dynamics video entered into the Gallery of
Fluid Motion of the 66th Annual Meeting of the APS Division of Fluid Dynamics.


title: Localization Results for Zero Order Pseudodifferential Operators

abstract:
  We show phase space localization at suitable energies for zero order
pseudodifferential operators, implying non-propagation properties for the
associated evolution groups.


title:
Uniform energy bound and asymptotics for the Maxwell field on a slowly
  rotating Kerr black hole exterior

abstract:
  We consider the Maxwell equation in the exterior of a very slowly rotating
Kerr black hole. For this system, we prove the boundedness of a positive
definite energy on each hypersurface of constant $t$. We also prove the
convergence of each solution to a stationary Coulomb solution. We separate a
general solution into the charged, Coulomb part and the uncharged part.
Convergence to the Coulomb solutions follows from the fact that the uncharged
part satisfies a Morawetz estimate, i.e. that a spatially localised energy
density is integrable in time. For the unchanged part, we study both the full
Maxwell equation and the Fackerell-Ipser equation for one component. To treat
the Fackerell-Ipser equation, we use a Fourier transform in $t$. For the
Fackerell-Ipser equation, we prove a refined Morawetz estimate that controls
3/2 derivatives with no loss near the orbiting null geodesics.


title: Clustering Memes in Social Media

abstract:
  The increasing pervasiveness of social media creates new opportunities to
study human social behavior, while challenging our capability to analyze their
massive data streams. One of the emerging tasks is to distinguish between
different kinds of activities, for example engineered misinformation campaigns
versus spontaneous communication. Such detection problems require a formal
definition of meme, or unit of information that can spread from person to
person through the social network. Once a meme is identified, supervised
learning methods can be applied to classify different types of communication.
The appropriate granularity of a meme, however, is hardly captured from
existing entities such as tags and keywords. Here we present a framework for
the novel task of detecting memes by clustering messages from large streams of
social data. We evaluate various similarity measures that leverage content,
metadata, network features, and their combinations. We also explore the idea of
pre-clustering on the basis of existing entities. A systematic evaluation is
carried out using a manually curated dataset as ground truth. Our analysis
shows that pre-clustering and a combination of heterogeneous features yield the
best trade-off between number of clusters and their quality, demonstrating that
a simple combination based on pairwise maximization of similarity is as
effective as a non-trivial optimization of parameters. Our approach is fully
automatic, unsupervised, and scalable for real-time detection of memes in
streaming data.

categories: cs.SI cs.CY physics.data-an physics.soc-ph


title: A theorem on measures in dimension 2 and applications to vortex sheets

abstract:
  We find conditions under which measures belong to . Next we show that
measures generated by Prandtl, Kaden as well as Pullin spirals, objects
considered by physicists as incompressible flows generating vorticity, satisfy
assumptions of our theorem, thus they are (locally) elements of . Moreover, as
a by-product, we prove an embedding of the space of Morrey type measures in .


title: Two statistical procedures for mapping large-angle non-Gaussianity

abstract:
  A convincing detection of primordial non-Gaussianity in the cosmic background
radiation (CMB) is essential to probe the physics of the early universe. Since
a single statistical estimator can hardly be suitable to detect the various
possible forms of non-Gaussianity, it is important to employ different
statistical indicators to study non-Gaussianity of CMB. This has motivated the
proposal of a number statistical tools, including two large-angle indicators
based on skewness and kurtosis of spherical caps of CMB sky-sphere. Although
suitable to detect fairly large non-Gaussianity they are unable to detect
non-Gaussianity within the Planck bounds, and exhibit power spectra with
undesirable oscillation pattern. Here we use several thousands simulated CMB
maps to examine interrelated problems regarding advances of these spherical
patches procedures. We examine whether a change in the choice of the patches
could enhance the sensitivity of the procedures well enough to detect
large-angle non-Gaussianity within the Planck bounds. To this end, a new
statistical procedure with non-overlapping cells is proposed and its capability
is established. We also study whether this new procedure is capable to smooth
out the undesirable oscillation pattern in the skewness and kurtosis power
spectra of the spherical caps procedure. We show that the new procedure solves
this problem, making clear this unexpected power spectra pattern does not have
a physical origin, but rather presumably arises from the overlapping obtained
with the spherical caps approach. Finally, we make a comparative analysis of
this new statistical procedure with the spherical caps routine, determine their
lower bounds for non-Gaussianity detection, and make apparent their relative
strength and sensitivity.


title: The Lumer-Phillips Theorem For Two--parameter $C_0$--semigroups

abstract:
  In this paper we extend the Lumer-Phillips theorem to the context of
two--parameter C_0-semigroup of contractions. That is, we characterize the
infinitesimal generators of two--parameter C_0-semigroups of contractions.
Conditions on the behavior of the resolvent of operators, which are necessary
and sufficient for the pair of operators to be the infinitesimal generator of a
C_0-semigroup of contractions are given.


title: Magnetic Trapping of Molecules via Optical Loading and Magnetic Slowing

abstract:
  Calcium monofluoride (CaF) is magnetically slowed and trapped using optical
pumping. Starting from a collisionally cooled slow beam, CaF with an initial
velocity of ~ 30 m/s is slowed via magnetic forces as it enters a 800 mK deep
magnetic trap. Employing two-stage optical pumping, CaF is irreversibly loaded
into the trap via two scattered photons. We observe a trap lifetime exceeding
500 ms, limited by background collisions. This method paves the way for cooling
and magnetic trapping of chemically diverse molecules without closed cycling
transitions.


title: Fluid Mechanics of Everyday Objects

abstract:
  High speed Schlieren videos were produced highlighting the fluid mechanics
found in everyday objects. This video (entry 102369) was submitted as part of
the Gallery of Fluid Motion 2013, which is a showcase of fluid dynamics videos.


title: Traveling Trends: Social Butterflies or Frequent Fliers?

abstract:
  Trending topics are the online conversations that grab collective attention
on social media. They are continually changing and often reflect exogenous
events that happen in the real world. Trends are localized in space and time as
they are driven by activity in specific geographic areas that act as sources of
traffic and information flow. Taken independently, trends and geography have
been discussed in recent literature on online social media; although, so far,
little has been done to characterize the relation between trends and geography.
Here we investigate more than eleven thousand topics that trended on Twitter in
63 main US locations during a period of 50 days in 2013. This data allows us to
study the origins and pathways of trends, how they compete for popularity at
the local level to emerge as winners at the country level, and what dynamics
underlie their production and consumption in different geographic areas. We
identify two main classes of trending topics: those that surface locally,
coinciding with three different geographic clusters (East coast, Midwest and
Southwest); and those that emerge globally from several metropolitan areas,
coinciding with the major air traffic hubs of the country. These hubs act as
trendsetters, generating topics that eventually trend at the country level, and
driving the conversation across the country. This poses an intriguing
conjecture, drawing a parallel between the spread of information and diseases:
Do trends travel faster by airplane than over the Internet?


title:
Simulating the Anisotropic Clustering of Luminous Red Galaxies with
  Subhalos: A Direct Confrontation with Observation and Cosmological
  Implications

abstract:
  We model the apparent clustering anisotropy of Luminous Red Galaxies (LRGs)
in the Sloan Digital Sky Survey using subhalos identified in cosmological
$N$-body simulations. We first conduct a Markov-chain Monte Carlo analysis on
the parameters characterizing subhalos hosting LRGs assuming a specific
$\Lambda$CDM cosmology on which we run the simulations. We show that simple
models with central and satellite subhalos can explain the observed multipole
moments of the power spectrum up to hexadecapole on large scales
($k\lesssim0.3~h\mathrm{Mpc}^{-1}$). A satellite fraction of $20$ to $30$ per
cent is favored weakly depending on the detail of the model. The fraction is
shown to be robust when we adopt a more refined model based on the halo
occupation number from the literature. We then vary cosmological parameters
controlling the anisotropy in redshift-space effectively by deforming the
simulation box (the Alcock-Paczynski effect) and changing the amplitude of the
velocities (the redshift-space distortions). We demonstrate that we can
constrain the geometry of the universe, the structure growth rate, and the
parameters characterizing LRGs simultaneously. This is a step toward
cosmological analysis with realistic bias description beyond empirical bias
functions with nuisance parameters.


title:
Front propagation in geometric and phase field models of stratified
  media

abstract:
  We study front propagation problems for forced mean curvature flows and their
phase field variants that take place in stratified media, i.e., heterogeneous
media whose characteristics do not vary in one direction. We consider phase
change fronts in infinite cylinders whose axis coincides with the symmetry axis
of the medium. Using the recently developed variational approaches, we provide
a convergence result relating asymptotic in time front propagation in the
diffuse interface case to that in the sharp interface case, for suitably
balanced nonlinearities of Allen-Cahn type. The result is established by using
arguments in the spirit of $\Gamma$-convergence, to obtain a correspondence
between the minimizers of an exponentially weighted Ginzburg-Landau type
functional and the minimizers of an exponentially weighted area type
functional. These minimizers yield the fastest traveling waves invading a given
stable equilibrium in the respective models and determine the asymptotic
propagation speeds for front-like initial data. We further show that
generically these fronts are the exponentially stable global attractors for
this kind of initial data and give sufficient conditions under which complete
phase change occurs via the formation of the considered fronts.


title:
Charge disproportionation without charge transfer in the rare-earth
  nickelates as a possible mechanism for the metal-insulator transition

abstract:
  We study a model for the metal-insulator (MI) transition in the rare-earth
nickelates RNiO$_3$, based upon a negative charge transfer energy and coupling
to a rock-salt like lattice distortion of the NiO$_6$ octahedra. Using exact
diagonalization and the Hartree-Fock approximation we demonstrate that
electrons couple strongly to these distortions. For small distortions the
system is metallic, with ground state of predominantly $d^8\ligand$ character,
where $\ligand$ denotes a ligand hole. For sufficiently large distortions
($\delta d_{\rm Ni-O} \sim 0.05 - 0.10\AA$), however, a gap opens at the Fermi
energy as the system enters a periodically distorted state alternating along
the three crystallographic axes, with $(d^8\ligand^2)_{S=0}(d^8)_{S=1}$
character, where $S$ is the total spin. Thus the MI transition may be viewed as
being driven by an internal volume "collapse" where the NiO$_6$ octahedra with
two ligand holes shrink around their central Ni, while the remaining octahedra
expand accordingly, resulting in the ($1/2,1/2,1/2$) superstructure observed in
x-ray diffraction in the insulating phase. This insulating state is an example
of a new type of charge ordering achieved without any actual movement of the
charge.


title: Non-Einstein source effects in massive gravity

abstract:
  We exhibit novel effects (absent in GR) of sources in massive gravity. First,
we show that removing its ghost mode forces a field-current identity: The
metric's trace is locally proportional to that of its stress tensor; a point
source implies a metric singularity enhanced by the square of the graviton's
range. Second, exterior solutions acquire spatial stress hair--their metric
components depend on the interior T_ij. Also, in contrast to naive
expectations, the Newtonian potential of a source is now determined by both its
spatial stress and mass. Our explicit results are obtained at linear,
Fierz-Pauli, level, but qualitatively persist nonlinearly.


title: Complexity of Multilevel Monte Carlo Tau-Leaping

abstract:
  Tau-leaping is a popular discretization method for generating approximate
paths of continuous time, discrete space, Markov chains, notably for
biochemical reaction systems. To compute expected values in this context, an
appropriate multilevel Monte Carlo form of tau-leaping has been shown to
improve efficiency dramatically. In this work we derive new analytic results
concerning the computational complexity of multilevel Monte Carlo tau-leaping
that are significantly sharper than previous ones. We avoid taking asymptotic
limits, and focus on a practical setting where the system size is large enough
for many events to take place along a path, so that exact simulation of paths
is expensive, making tau-leaping an attractive option. We use a general scaling
of the system components that allows for the reaction rate constants and the
abundances of species to vary over several orders of magnitude, and we exploit
the random time change representation developed by Kurtz. The key feature of
the analysis that allows for the sharper bounds is that when comparing relevant
pairs of processes we analyze the variance of their difference directly rather
than bounding via the second moment. Use of the second moment is natural in the
setting of a diffusion equation, where multilevel was first developed and where
strong convergence results for numerical methods are readily available, but is
not optimal for the Poisson-driven jump systems that we consider here. We also
present computational results that illustrate the new analysis.


title: Dynamics of a three-photon state interacting with a quantum dot

abstract:
  In this paper, we study the dynamics of the interaction of a three-photon
state and a quantum dot embedded in a semiconductor cavity. In the first place,
we consider an ideal cavity in which the effects due to the environment are
neglected. Under this conditions, the most important feature of the dynamics is
its periodicity, which may be seen on the temporal evolution of the light
state. The entanglement dynamics, which is studied through the negativity and
the linear entropy, shows a periodic behaviour too. On the other hand, when
considering the interaction between the cavity and the environment, taking into
account both an incoherent pumping and a photon leakage, the dynamics is no
longer periodic. Instead, it may be seen that the entanglement reach stationary
values, which depend on the incoherent pumping and photon leakage rates.
Finally, we discuss the possibility of using this sort of systems for quantum
information processing.


title:
Logical gaps in the approximate solutions of the social learning game
  and an exact solution

abstract:
  After the social learning models were proposed, finding the solutions of the
games becomes a well-defined mathematical question. However, almost all papers
on the games and their applications are based on solutions built upon either an
add-hoc argument or a twisted Bayesian analysis of the games. Here, we present
logical gaps in those solutions and an exact solution of our own. We also
introduced a minor extension to the original game such that not only logical
difference but also difference in action outcomes among those solutions become
visible.


title: Relics of ancient post-AGB stars in a primitive meteorite

abstract:
  Graphite is one of the many presolar circumstellar condensate species found
in primitive meteorites. While the isotopic compositions of low-density
graphite grains indicate an origin in core-collapse supernovae, some
high-density grains have extreme isotopic anomalies in C, Ca and Ti, which
cannot be explained by envelope predictions of asymptotic giant branch (AGB)
stars or theoretical supernova models. The Ca and Ti isotopic anomalies,
however, match the predictions of He-shell abundances in AGB stars. In this
study, we show that the C, Ca, and Ti isotopic anomalies are consistent with
nucleosynthesis predictions of the H-ingestion phase during a very late thermal
pulse (VLTP) event in post-AGB stars. The low $^{12}$C/$^{13}$C isotopic ratios
in these grains are a result of abundant $^{12}$C efficiently capturing the
protons that are being ingested during the VLTP. Very high neutron densities of
$\sim 10^{15}$ cm$^{-3}$, typical of the $i$-process, are achieved during this
phase in post-AGB stars. The large $^{42,43,44}$Ca excesses in some graphite
grains are indicative of neutron capture nucleosynthesis during VLTP. The
comparison of VLTP nucleosynthesis calculations to the graphite data also
indicate that apparent anomalies in the Ti isotopic ratios are due to large
contributions from $^{46,48}$Ca, which cannot be resolved from the isobars
$^{46,48}$Ti during the measurements. We conclude that presolar graphite grains
with moderate to extreme Ca and Ti isotopic anomalies originate in post-AGB
stars that suffer a very late thermal pulse.


title:
Pointwise upper estimates for transition probability of continuous time
  random walks on graphs

abstract:
  Let $X$ be a continuous time random walk on a weighted graph. Given the
on-diagonal upper bounds of transition probabilities at two vertices $x_1$ and
$x_2$, we use an adapted metric initiated by Davies, and obtain Gaussian upper
estimates for the off-diagonal transition probability $P_{x_1}(X_t=x_2)$.


title:
Strange Inter-layer Properties of $Ba(Fe_{1-x}Co_x)2As_2$ Appearing in
  Ultrasonic Measurements

abstract:
  We have investigated the elastic constant C33 of Ba(Fe1-xCox)2As2 with eight
different Co concentrations by ultrasonic measurement. We found remarkable
elastic anomalies near the quantum critical point. We have studied them by
measuring the electrical resistivity, heat capacity, and ultrasonic attenuation
in addition to the elastic constant. These results have revealed that the
inter-layer three-dimensional properties appearing in C33 to be possibly
originated from the magnetic character of these materials. Our data about the
elastic constant C33 highlight the importance of controlling the c-axis length
in the emergence of superconductivity in iron-based superconductors.


title: Tensor decomposition of isocrystals characterizes Mumford curves

abstract:
  We seek an appropriate definition for a Shimura curve of Hodge type in
positive characteristics via characterizing curves in positive characteristics
which are reduction of Shimura curve over $\mathbb{C}$. In this paper, we study
the liftablity of a curve in the moduli space of principally polarized abelian
varieties over $k, \text{char} k=p$. We show that in the generic ordinary case,
some tensor decomposition of the isocrystal associated to the family imply that
this curve can be lifted to a Shimura curve.


title:
Optical characterization of electron-phonon interactions at the saddle
  point in graphene

abstract:
  The role of electron-phonon interactions is experimentally and theoretically
investigated near the saddle point absorption peak of graphene. The
differential optical transmission spectra of multiple, non-interacting layers
of graphene reveals the dominant role played by electron-acoustic phonon
coupling in bandstructure renormalization. Using a Born approximation for
electron-phonon coupling and experimental estimates of the dynamic phonon
lattice temperature, we deduce the effective acoustic deformation potential to
be $D^{\rm ac}_{\rm eff} \simeq 5$eV. This value is in accord with recent
theoretical predictions but differs substantially from those obtained using
electrical transport measurements.


title: New visual companions of solar-type stars within 25 pc

abstract:
  We report the discovery of faint common-proper-motion companions to the
nearby southern solar-type stars HD43162, HD67199, HD114837, HD114853,
HD129502, HD165185, HD197214, and HD212330 from near-infrared imaging and
astrometry. We also confirm the previously identified tertiary components
around HD165401 and HD188088. Since the majority of these stars were already
known as binaries, they ascend now to higher-level systems. A particularly
interesting case is the G6.5V BYDra-type variable HD43162, which harbors two
common-proper-motion companions at distances of 410 AU and 2740 AU. Our limited
study shows that the inventory of common-proper-motion companions around nearby
bright stars is still not completely known.


title:
Measuring chemical evolution and gravitational dependence of \alpha
  using ultraviolet Fe V and Ni V transitions in white-dwarf spectra

abstract:
  In this paper, we present the details of the ab initio high-precision
configuration interaction and many-body perturbation theory calculations that
were used in a previous work to place limits on the dependence of the
fine-structure constant, alpha, on the gravitational field of the white-dwarf
star G191-B2B. These calculations were combined with laboratory wavelengths and
spectra from the Hubble Space Telescope Imaging Spectrograph to obtain limits
on the gravitational alpha-dependence using Fe V and Ni V transitions. The
uncertainty in these results are dominated by the uncertainty in the laboratory
wavelengths. In this work we also present ab initio calculations of the
isotopic shifts of the Fe V transitions. We show that improved laboratory
spectra will enable determination of the relative isotope abundances in Fe V to
an accuracy ~20%. Therefore this work provides a strong motivation for new
laboratory measurements.


title:
New Families of $p$-ary Sequences of Period $\frac{p^n-1}{2}$ With Low
  Maximum Correlation Magnitude

abstract:
  Let $p$ be an odd prime such that $p \equiv 3\;{\rm mod}\;4$ and $n$ be an
odd integer. In this paper, two new families of $p$-ary sequences of period $N
= \frac{p^n-1}{2}$ are constructed by two decimated $p$-ary m-sequences $m(2t)$
and $m(dt)$, where $d = 4$ and $d = (p^n + 1)/2=N+1$. The upper bound on the
magnitude of correlation values of two sequences in the family is derived using
Weil bound. Their upper bound is derived as $\frac{3}{\sqrt{2}}
\sqrt{N+\frac{1}{2}}+\frac{1}{2}$ and the family size is 4N, which is four
times the period of the sequence.


title: Quantum Fisher information for states in exponential form

abstract:
  We derive explicit expressions for the quantum Fisher information and the
symmetric logarithmic derivative (SLD) of a quantum state in the exponential
form; the SLD is expressed in terms of the generator. Applications include
quantum-metrology problems with Gaussian states and general thermal states.
Specifically, we give the SLD for a Gaussian state in two forms, in terms of
its generator and its moments; the Fisher information is also calculated for
both forms. Special cases are discussed, including pure, degenerate, and very
noisy Gaussian states.


title:
Slow Exciton Spin Relaxation in Single Self-Assembled
  In$_{1-x}$Ga$_x$As/GaAs Quantum Dots

abstract:
  We calculate the acoustic phonon-assisted exciton spin relaxation in single
self-assembled In$_{1-x}$Ga$_x$As/GaAs quantum dots using an atomic empirical
pseudopotential method. We show that the transition from bright to dark exciton
states is induced by Coulomb correlation effects. The exciton spin relaxation
time obtained from sophisticated configuration interaction calculations is
approximately 15--55 $\mu$s in pure InAs/GaAs QDs and even longer in alloy
dots. These results contradict previous theoretical and experimental results,
which suggest very short exciton spin times (a few ns), but agree with more
recent experiments that suggest that excitons have long spin relaxation times
($>$ 1 $\mu$s).


title:
Two-setting multi-site Bell inequalities for loophole-free tests with up
  to 50% loss

abstract:
  We consider Bell experiments with N spatially separated qubits where loss is
present and restrict to two measurement settings per site. We note the
Mermin-Ardehali-Belinskii-Klyshko (MABK) Bell inequalities do not present a
tight bound for the predictions of local hidden variable (LHV) theories. The
Holder-type Bell inequality derived by Cavalcanti, Foster, Reid and Drummond
provides a tighter bound, for high losses. We analyse the actual tight bound
for the MABK inequalities, given the measure W=\prod_{k=1}^{N}\eta_{k} of
overall detection efficiency, where \eta_{k} is the efficiency at the site k .
Using these inequalities, we confirm that the maximally entangled
Greenberger-Horne-Zeilinger state enables loophole-free falsification of LHV
theories provided \prod_{k=1}^{N}\eta_{k}>2^{(2-N)}, which implies a symmetric
threshold efficiency of \eta\rightarrow50%, as N\rightarrow\infty .
Furthermore, loophole-free violations remain possible, even when the efficiency
at some sites is reduced well below 0.5, provided N>3 .


title:
Criteria for genuine N-partite continuous variable entanglement and
  Einstein-Podolsky_Rosen steering

abstract:
  Following previous work, we distinguish between genuine $N$-partite
entanglement and full $N$-partite inseparability. Accordingly, we derive
criteria to detect genuine multipartite entanglement using continuous variable
(position and momentum) measurements. Our criteria are similar but different to
those based on the van Loock-Furusawa inequalities, which detect full
$N$-partite inseparability. We explain how the criteria can be used to detect
the genuine $N$-partite entanglement of continuous variable states generated
from squeezed and vacuum state inputs, including the continuous variable
Greenberger-Horne-Zeilinger state, with explicit predictions for up to $N=9$$
$. This makes our work accessible to experiment. For $N=3$, we also present
criteria for tripartite Einstein-Podolsky-Rosen (EPR) steering. These criteria
provide a means to demonstrate a genuine three-party EPR paradox, in which any
single party is steerable by the remaining two parties.


title: An incomplete variant of Wilson's congruence

abstract:
  This article examines the nontrivial solutions of the congruence \[
(p-1)\cdots(p-r) \equiv -1 \pmod p. \] We discuss heuristics for the proportion
of primes $p$ that have exactly $N$ solutions to this congruence. We supply
numerical evidence in favour of these conjectures, and discuss the algorithms
used in our calculations.


title:
An analysis on optimization of undulator in self-seeding free electron
  laser

abstract:
  A simple analysis is given for optimum length of undulator in self-seeding
free electron laser (FEL). The obtained relations show the correlation between
the undulator length and the system parameters. The power required for the
seeding in the second part undulator and overall efficiency to
monochromatizating the seeding settle on the length of the first part
undulator; the magnitude of seeding power dominates the length of the second
part undulator; the whole length of the undulators in self-seeding FEL is
determined by the overall efficiency to get coherent seed, it is about half as
long again as that of SASE, not including the dispersion section. The
requirement of the dispersion section strength is also analyzed.


title: Design of a Double Spoke Cavity for C-ADS

abstract:
  The RF design of a 325MHz {\beta}=0.37 superconducting double spoke cavity
for China ADS has been finished. In this paper, the optimization of the spoke
cavity is described in detail. The main goal in the RF design is to decrease
the normalized surface field. We use the elliptic column instead of cylinder to
decrease the normalized magnetic field. The RF simulation gives the optimum
parameters Ep/Eacc of 4.39 and Bp/Eacc of 7.15mT/(MV/m), which meet the
requirement of C-ADS.


title:
Nonlinear processes responsible for mid-infrared and blue light
  generation in alkali vapours

abstract:
  The nonlinear processes responsible for frequency up- and down-conversion of
resonant low-intensity laser radiation in Rb vapour have been evaluated from
the spatial and temporal properties of blue and mid-IR light resulting from
wave mixing.


title: Indirect Detection of Dark Matter with gamma rays

abstract:
  The details of what constitutes the majority of the mass that makes up dark
matter in the Universe remains one of the prime puzzles of cosmology and
particle physics today - eighty years after the first observational
indications. Today, it is widely accepted that dark matter exists and that it
is very likely composed of elementary particles - that are weakly interacting
and massive (WIMPs for Weakly Interacting Massive Particles). As important as
dark matter is in our understanding of cosmology, the detection of these
particles has so far been elusive. Their primary properties such as mass and
interaction cross sections are still unknown. Indirect detection searches for
the products of WIMP annihilation or decay. This is generally done through
observations of gamma-ray photons or cosmic rays. Instruments such as the
Fermi-LAT, H.E.S.S., MAGIC and VERITAS, combined with the future Cherenkov
Telescope Array (CTA) will provide important and complementary constraints to
other search techniques. Given the expected sensitivities of all search
techniques, we are at a stage where the WIMP scenario is facing stringent tests
and it can be expected that WIMPs will be either be detected or the scenario
will be so severely constrained that it will have to be re-thought. In this
sense we are on the "Threshold of Discovery". In this article, I will give a
general overview over the current status and the future expectations for
indirect searches for dark matter (WIMP) particles.


title: The Most Magnetic Stars

abstract:
  Observations of magnetic A, B and O stars show that the poloidal magnetic
flux per unit mass has an upper bound of 10^-6.5 G cm^2/g. A similar upper
bound is found for magnetic white dwarfs even though the highest magnetic field
strengths at their surfaces are much larger. For magnetic A and B stars there
also appears to be a well defined lower bound below which the incidence of
magnetism declines rapidly. According to recent hypotheses, both groups of
stars may result from merging stars and owe their strong magnetism to fields
generated by a dynamo mechanism as they merge. We postulate a simple dynamo
that generates magnetic field from differential rotation. The growth of
magnetic fields is limited by the requirement that the poloidal field
stabilizes the toroidal and vice versa. While magnetic torques dissipate the
differential rotation, toroidal field is generated from poloidal by an Omega
dynamo. We further suppose that mechanisms that lead to the decay of toroidal
field lead to the generation of poloidal. Both poloidal and toroidal fields
reach a stable configuration which is independent of the size of small initial
seed fields but proportional to the initial differential rotation. We pose the
hypothesis that strongly magnetic stars form from the merging of two stellar
objects. The highest fields are generated when the merge introduces
differential rotation that amounts to critical break up velocity within the
condensed object. Calibration of a simplistic dynamo model with the observed
maximum flux per unit mass for main-sequence stars and white dwarfs indicates
that about 1.5x10^-4 of the decaying toroidal flux must appear as poloidal. The
highest fields in single white dwarfs are generated when two degenerate cores
merge inside a common envelope or when two white dwarfs merge by
gravitational-radiation angular momentum loss.


title: Low-energy electric dipole response of Sn isotopes

abstract:
  We study the low-energy dipole (LED) strength distribution along the Sn
isotopic chain in both the isoscalar (IS) and the isovector (IV, or E1)
electric channels, to provide testable predictions and guidance for new
experiments with stable targets and radioactive beams. We use the
self-consistent Quasi-particle Random-Phase Approximation (QRPA) with
finite-range interactions and mainly the Gogny D1S force. We analyze also the
performance of a realistic two-body interaction supplemented by a
phenomenological three-body contact term. We find that from N=50 and up to the
N=82 shell closure (132Sn) the lowest-energy part of the IS-LED spectrum is
dominated by a collective transition whose properties vary smoothly with
neutron number and which cannot be interpreted as a neutron-skin oscillation.
For the neutron-rich species this state contributes to the E1 strength below
particle threshold, but much more E1 strength is carried by other, weak but
numerous transitions around or above threshold. We find that strong structural
changes in the spectrum take effect beyond N=82, namely increased LED strength
and lower excitation energies. Our results with the Gogny interaction are
compatible with existing data. On this basis we predict that a) the summed IS
strength below particle threshold shall be of the same order of magnitude for
N=50-82, b) the summed E1 strength up to approximately 12 MeV shall be similar
for N=50-82 MeV, while c) the summed E1 strength below threshold shall be of
the same order of magnitude for N ~ 64 - 82 and much weaker for the lighter,
more-symmetric isotopes. We point out a general agreement of our results with
other non-relativistic studies, the absence of a collective IS mode in some of
those studies, and a possibly radical disagreement with relativistic models.


title: Einstein-Yang-Mills theory : I. Asymptotic symmetries

abstract:
  Asymptotic symmetries of the Einstein-Yang-Mills system with or without
cosmological constant are explicitly worked out in a unified manner. In
agreement with a recent conjecture, one finds a Virasoro-Kac-Moody type algebra
not only in three dimensions but also in the four dimensional asymptotically
flat case.


title: Construction of conformal mappings by generalized polarization tensors

abstract:
  We present a new systematic method to construct the conformal mapping from
outside the unit disc to outside of a simply connected domain using the
generalized polarization tensors. We also present some numerical results to
validate effectiveness of the method.


title: Analyzing Big Data with Dynamic Quantum Clustering

abstract:
  How does one search for a needle in a multi-dimensional haystack without
knowing what a needle is and without knowing if there is one in the haystack?
This kind of problem requires a paradigm shift - away from hypothesis driven
searches of the data - towards a methodology that lets the data speak for
itself. Dynamic Quantum Clustering (DQC) is such a methodology. DQC is a
powerful visual method that works with big, high-dimensional data. It exploits
variations of the density of the data (in feature space) and unearths subsets
of the data that exhibit correlations among all the measured variables. The
outcome of a DQC analysis is a movie that shows how and why sets of data-points
are eventually classified as members of simple clusters or as members of - what
we call - extended structures. This allows DQC to be successfully used in a
non-conventional exploratory mode where one searches data for unexpected
information without the need to model the data. We show how this works for big,
complex, real-world datasets that come from five distinct fields: i.e., x-ray
nano-chemistry, condensed matter, biology, seismology and finance. These
studies show how DQC excels at uncovering unexpected, small - but meaningful -
subsets of the data that contain important information. We also establish an
important new result: namely, that big, complex datasets often contain
interesting structures that will be missed by many conventional clustering
techniques. Experience shows that these structures appear frequently enough
that it is crucial to know they can exist, and that when they do, they encode
important hidden information. In short, we not only demonstrate that DQC can be
flexibly applied to datasets that present significantly different challenges,
we also show how a simple analysis can be used to look for the needle in the
haystack, determine what it is, and find what this means.


title:
A Sum-of-Squares Approach to the Analysis of Zeno Stability in
  Polynomial Hybrid Systems

abstract:
  Hybrid dynamical systems can exhibit many unique phenomena, such as Zeno
behavior. Zeno behavior is the occurrence of infinite discrete transitions in
finite time. Zeno behavior has been likened to a form of finite-time asymptotic
stability, and corresponding Lyapunov theorems have been developed. In this
paper, we propose a method to construct Lyapunov functions to prove Zeno
stability of compact sets in cyclic hybrid systems with parametric
uncertainties in the vector fields, domains and guard sets, and reset maps
utilizing sum-of-squares programming. This technique can easily be applied to
cyclic hybrid systems without parametric uncertainties as well. Examples
illustrating the use of the proposed technique are also provided.


title: Emergent irreversibility and entanglement spectrum statistics

abstract:
  We study the problem of irreversibility when the dynamical evolution of a
many-body system is described by a stochastic quantum circuit. Such evolution
is more general than a Hamiltonian one, and since energy levels are not well
defined, the well-established connection between the statistical fluctuations
of the energy spectrum and irreversibility cannot be made. We show that the
entanglement spectrum provides a more general connection. Irreversibility is
marked by a failure of a disentangling algorithm and is preceded by the
appearance of Wigner-Dyson statistical fluctuations in the entanglement
spectrum. This analysis can be done at the wave-function level and offers an
alternative route to study quantum chaos and quantum integrability.


title:
Max-Min Energy Efficient Beamforming for Multicell Multiuser Joint
  Transmission Systems

abstract:
  Energy efficient communication technology has attracted much attention due to
the explosive growth of energy consumption in current wireless communication
systems. In this letter we focus on fairness-based energy efficiency and aim to
maximize the minimum user energy efficiency in the multicell multiuser joint
beamforming system, taking both dynamic and static power consumptions into
account. This optimization problem is a non-convex fractional programming
problem and hard to tackle. In order to find its solution, the original problem
is transformed into a parameterized polynomial subtractive form by exploiting
the relationship between the user rate and the minimum mean square error, and
using the fractional programming theorem. Furthermore, an iterative algorithm
with proved convergence is developed to achieve a near-optimal performance.
Numerical results validate the effectiveness of the proposed solution and show
that our algorithm significantly outperforms the max-min rate optimization
algorithm in terms of maximizing the minimum energy efficiency.


title:
Measurement of branching fractions for B \to J/\psi \eta K decays and
  search for a narrow resonance in the J/\psi \eta final state

abstract:
  We report an observation of the $B^{\pm} \to J/\psi \eta K^{\pm}$ and $B^0
\to J/\psi \eta K^0_S$ decays using 772$\times 10^{6}$ $B\bar{B}$ pairs
collected at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB
asymmetric-energy $e^+e^-$ collider. We obtain the branching fractions ${\cal
B}(B^{\pm}\rightarrow J/\psi\eta K^{\pm})=(1.27\pm 0.11{\rm (stat.)\pm 0.11{\rm
(syst.)})}\times10^{-4}$ and ${\cal B}(B^0\to J/\psi \eta K^0_S)=(5.22 \pm 0.78
{\rm(stat.)} \pm 0.49{\rm(syst.)})\times10^{-5}$. We search for a new narrow
charmonium(-like) state $X$ in the $J/\psi \eta$ mass spectrum and find no
significant excess. We set upper limits on the product of branching fractions,
${\cal B}(B^\pm \to XK^\pm){\cal B}(X \to J/\psi \eta)$, at 3872 MeV$/c^2$
where a $C$-odd partner of X(3872) may exist, at $\psi(4040)$ and $\psi(4160)$
assuming their known mass and width, and over a range from 3.8 to 4.8
GeV$/c^2$. % at a 5 MeV$/c^2$ step. The obtained upper limits at 90% confidence
level for $X^{C{\rm -odd}}(3872)$, $\psi(4040)$ and $\psi(4160)$ are 3.8$\times
10^{-6}$, 15.5$\times 10^{-6}$ and 7.4$\times 10^{-6}$, respectively.


title: Early Phase Observations of the KVN+VERA Joint Array

abstract:
  The KVN+VERA array is a joint VLBI project of seven VLBI stations spread
throughout Korea and Japan. Since the first fringe detection in 2008, the early
phase observations of the KVN+VERA have been carried out every several months.
Currently, two observing bands of 22 and 43 GHz are available. We are aiming
for early realization of science observations with the 1-Gbps recording system
from 2012.


title: Vacuum Energy Accretion and Primordial Black Holes in Brans-Dicke theory

abstract:
  In this paper, we investigate the evolution of primordial black hole (PBH) in
vacuum-dominated era within Brans-Dicke cosmology. We consider the accretion of
vacuum energy by PBHs and found that vacuum energy accretion efficiency should
be less than 0.61. We also study the evaporation of PBHs where we conclude that
larger the value of accretion efficiency longer live the PBHs. We also find
that PBHs evaporate at a quicker rate in Brans-Dicke theory compared with
Standard Cosmology.


title: Theorems about includings for multivalued mappings

abstract:
  This paper is devoted to studying of some properties of multivalued mappings
in Euclidean space. There were proved theorems on a fixed point for multivalued
mappings whose restrictions to some subset in the closure of a domain satisfy
"a coacute angle condition" or "a strict coacute angle condition". There also
were obtained similar results for restrictions of multivalued mappings
satisfying some metric limitations.


title: On the Cauchy-Born Approximation at Finite Temperature

abstract:
  We address several issues regarding the derivation and implementation of the
Cauchy-Born approximation of the stress at finite temperature. In particular,
an asymptotic expansion is employed to derive a closed form expression for the
first Piola-Kirchhoff stress. For systems under periodic boundary conditions, a
derivation is presented, which takes into account the translational invariance
and clarifies the removal of the zero phonon modes. Also revealed by the
asymptotic approach is the role of the smoothness of the interatomic potential.
Several numerical examples are provided to validate this approach.


title: Positive Limit-Fourier Transform of Farey Fractions

abstract:
  We consider the entity of modified Farey fractions via a function F defined
on the direct sum of Z/2Z and we prove that -F has a non negative Limit-Fourier
transform up to one exceptional coefficient.


title: Correlation between Internal States and Strength in Bulk Metallic Glass

abstract:
  The internal states or local structures of bulk metallic glass (BMGs) can be
well reflected from the changes of density, structural relaxation as well as
the elastic constants. With the increasing free volume (FV) content, more local
atomic clusters are capable of simultaneous plastic shear at different sites in
the metallic glasses, inducing large plasticity. In this work, we report a
close correlation between the internal states and strength in a BMG and
discover that the yield strength can be changed by varying of the casting
current, revealing that the yielding strength of BMGs is not only intrinsically
associated with the glass transition, but also with the internal states, such
as free volume and elastic properties. Such results may have some implications
for understanding the correlations between the internal states and mechanical
properties of BMGs.


title:
Fixed Parameter Inapproximability for Clique and SetCover in Time
  Super-exponential in OPT

abstract:
  In this paper, we consider proving inapproximability in terms of OPT and thus
we base the foundations of fixed parameter inapproximability.


title:
Physical Origin of Nonlinear transport in organic semiconductor at high
  carrier densities

abstract:
  The charge transport in some organic semiconductors demonstrates nonlinear
properties and further universal power-law scaling with both bias and
temperature. The physical origin of this behavior is investigated here using
variable range hopping theory. The results shows, this universal power-law
scaling can be well explained by variable range hopping theory . Relation to
the recent experimental data is also discussed.


title: Clifford algebra and the projective model of Elliptic spaces

abstract:
  I apply the algebraic framework developed in arXiv:1101.4542 to study
geometry of elliptic spaces in 1, 2, and 3 dimensions. The background material
on projectivised Clifford algebras and their application to Cayley-Klein
geometries is described in arXiv:1307.2917. The use of Clifford algebra largely
obviates the need for spherical trigonometry as elementary geometric
transformations such as projections, rejections, reflections, and rotations can
be accomplished with geometric multiplication. Furthermore, the same
transformations can be used in 3-dimensional elliptic space where effective use
of spherical trigonometry is problematic. I give explicit construction of
Clifford parallels and discuss their properties in detail. Clifford
translations are represented in a uniform fashion by geometric multiplication
as well. The emphasis of the exposition is on geometric structures and
computation rather than proofs.


title:
Nonsmooth Steepest Descent Method by Proximal Subdifferentials in
  Hilbert Spaces

abstract:
  In this paper, we first study nonsmooth steepest descent method for nonsmooth
functions defined on Hilbert space and establish the corresponding algorithm by
proximal subgradients. Then, we use this algorithm to find stationary points
for those functions satisfying prox-regularity and Lipschitzian continuity. As
one application, the established algorithm is used to search the minimizer of
lower semicontinuous and convex functions on finite-dimensional space. The
convergent theorem, as one extension and improvement of the existing converging
result for twice continuously differentiable convex functions, is also
presented therein.


title: On the asymptotic formula of L'(1, \chi)

abstract:
  Let $\chi$ be a quadratic Dirichlet character. In some literatures, various
asymptotic formulae of $L'(1,\chi)$, under the assumption that $L(1,\chi)$
takes a small value, were derived. In this paper, we will give a new treatment
unified for the odd and even cases, not depending on Kronecker limit formula.
For imaginary quadratic fields, our result coincides with Proposition 22.10 in
[1].


title:
Universal Einstein Relation Model in Disordered Organic Semiconductors
  under Quasi-equilibrium

abstract:
  It is still under debate whether the classical Einstein relation in
disordered organic semiconductors is valid. We investigated Einstein relation
in disordered organic semiconductors theoretically. The results show that, the
classic Einstein relation deviate dramatically with disorder and electric
field, even in the case of thermal equilibrium.


title: Low-cost photoplethysmograph solutions using the Raspberry Pi

abstract:
  Photoplethysmography is a prevalent, non-invasive heart monitoring method. In
this paper an implementation of photoplethysmography on the Raspberry Pi is
presented. Two modulation techniques are discussed, which make possible to
measure these signals by the Raspberry Pi, using an external sound card as A/D
converter. Furthermore, it is shown, how can digital signal processing improve
signal quality. The presented methods can be used in low-cost cardiac function
monitoring, in telemedicine applications and in education as well, since cheap
and current hardware are used. Full documentation and open-source software for
the measurement available:
http://www.noise.inf.u-szeged.hu/Instruments/raspberryplet/


title: Inter-layer Potential for Hexagonal Boron Nitride

abstract:
  A new interlayer force-field for layered hexagonal boron nitride (h-BN) based
structures is presented. The force-field contains three terms representing the
interlayer attraction due to dispersive interactions, repulsion due to
anisotropic overlaps of electron clouds, and monopolar electrostatic
interactions. With appropriate parameterization, the potential is able to
simultaneously capture well the binding and lateral sliding energies of planar
h-BN based dimer systems as well as the interlayer telescoping and rotation of
double walled boron-nitride nanotubes of different crystallographic
orientations. The new potential thus enables the accurate and efficient
modeling and simulation of large-scale h-BN based layered structures.


title:
Multifractal analysis of three-dimensional grayscale images: Estimation
  of generalized fractal dimension and singularity spectrum

abstract:
  A multifractal analysis is performed on a three-dimensional grayscale image
associated with a complex system. First, a procedure for generating 3D
synthetic images (2D image stacks) of a complex structure exhibiting
multifractal behaviour is described. Then, in order to characterize the 3D
system, the theoretical calculation of the generalized fractal dimension and
two different approaches for evaluating the singularity spectrum are presented.


title:
Computer simulation of effective viscosity of fluid-proppant mixture
  used in hydraulic fracturing

abstract:
  The paper presents results of numerical experiments performed to evaluate the
effective viscosity of a fluid-proppant mixture, used in hydraulic fracturing.
The results, obtained by two complimenting methods (the particle dynamics and
the smoothed particle hydrodynamics), coincide to the accuracy of standard
deviation. They provide an analytical equation for the dependence of effective
viscosity on the proppant concentration, needed for numerical simulation of the
hydraulic fracture propagation.


title:
Yrast state band of even 120-130Te isotopes under the framework of
  interacting boson model -1

abstract:
  In this paper, nuclear structure of yrast state bands of even-even 120-130Te
isotopes has been studied under the frame work of interacting boson model
(IBM-1). The theoretical energy levels for Z=52, even N = 68-78 up to 12+ state
have been obtained by using the MatLab 6.5 computer program. The ratio of the
excitation energies of first 4+ and first 2+ excited states, R4/2, has been
also calculated for those nuclei. The values of the parameters in the IBM-1
hamiltonian yield the best fit to the experimental energy spectrum. The results
are compared with the most recent experimental values where an acceptable
degree of agreement is achieved. Moreover, as a measure to quantify the
evolution, we have studied the transition rate R of some of the low-lying
quadrupole collective states in comparison to the available experimental data.
In this paper, the properties of even 120-130Te isotopes have been considered
to the U(5) transitional region of IBM-1.


title:
A finite presentation for the mapping class group of a nonorientable
  surface with Dehn twists and one crosscap slide as generators

abstract:
  Let N_{g,s} denote the nonorientable surface of genus g with s boundary
components. Recently Paris and Szepietowski obtained an explicit finite
presentation for the mapping class group M(N_{g,s}) of the surface N_{g,s},
where s\in{0,1} and g+s>3. Following this work we obtain a finite presentation
for the mapping class group M(N_{g,s}) with generators being Dehn twists and
one crosscap slide.


title: On the VLBI measurement of the Solar System acceleration

abstract:
  We propose new estimates of the secular aberration drift, mainly due to the
rotation of the Solar System about the Galactic center, based on up-to-date
VLBI observations and and improved method of outlier elimination. We fit
degree-2 vector spherical harmonics to extragalactic radio source proper motion
field derived from geodetic VLBI observations spanning 1979-2013. We pay
particular attention to the outlier elimination procedure to remove outliers
from (i) radio source coordinate time series and (ii) the proper motion sample.
We obtain more accurate values of the Solar system acceleration compared to
those in our previous paper. The acceleration vector is oriented towards the
Galactic center within 7 deg. The component perpendicular to the Galactic plane
is statistically insignificant. We show that an insufficient cleaning of the
data set can lead to strong variations in the dipole amplitude and orientation,
and statistically biased results.


title:
Numerical evaluation of Greens functions based on the Chebyshev
  expansion

abstract:
  We present a method to determine the impurity Greens function of the
interacting resonant level model (IRLM) using numerical simulation techniques
based on the expansion of a resolvent expression in terms of Chebyshev
polynomials. The iterative determination of the contributions to the expansion
is based on a Density Matrix Renormalisation Group algorithm. The spectral
function has lorentzian shape, where we can show that the width grows
monotonically with the interaction on the contact link. Moreover, for values of
the interaction compareable to the band width, there are additional peaks
showing up for energies located outside the conduction band.


title: Geometric juggling with q-analogues

abstract:
  We derive a combinatorial equilibrium for bounded juggling patterns with a
random, $q$-geometric throw distribution. The dynamics are analyzed via rook
placements on staircase Ferrers boards, which leads to a steady-state
distribution containing $q$-rook polynomial coefficients and $q$-Stirling
numbers of the second kind. We show that the equilibrium probabilities of the
bounded model can be uniformly approximated with the equilibrium probabilities
of a corresponding unbounded model. This observation leads to new limit
formulae for $q$-analogues.
  Keywords: juggling pattern; $q$-Stirling number of the second kind; Ferrers
board; Markov process; combinatorial equilibrium