title:
Probabilistic representation for solutions of a porous media type
  equation with Neumann boundary condition: the case of the half-line

abstract:
  The purpose of this paper consists in proposing a generalized solution for a
porous media type equation on a half-line with Neumann boundary condition and
prove a probabilistic representation of this solution in terms of an associated
microscopic diffusion. The main idea is to construct a stochastic differential
equation with reflection which has a solution in law and whose marginal law
densities provide the unique solution of the porous media type equation.


title: Aspherical manifolds that cannot be triangulated

abstract:
  Although Kirby and Siebenmann showed that there are manifolds that do not
admit PL structures, the possibility remained that all manifolds could be
triangulated. In the late seventies Galewski and Stern and independently
Matumoto showed that non-triangulable manifolds exist in all dimensions > 4 if
and only if homology 3-spheres with certain properties do not exist. In 2013
Manolescu showed that, indeed, there were no such homology 3-spheres and hence,
non-triangulable manifolds exist in each dimension >4. It follows from work of
Freedman in 1982 that there are 4-manifolds that cannot be triangulated. In
1991 Davis and Januszkiewicz applied a hyperbolization procedure to Freedman's
4-manifolds to get closed aspherical 4-manifolds that cannot be triangulated.
In this paper we apply hyperbolization techniques to the Galewski-Stern
manifolds to show that there exist closed aspherical n-manifolds that cannot be
triangulated for each n> 5. The question remains open in dimension 5.


title:
A Note on the Hypercomplex Riemann-Cauchy Like Relations for Quaternions
  and Laplace Equations

abstract:
  In this note it is worked out a new set of Laplace-Like equations for
quaternions through Riemann-Cauchy hypercomplex relations otained earlier
\cite{BorgesZeMarcio}. As in the theory of functions of a complex variable, it
is expected that this new set of Laplace-Like equations might be applied to a
large number of Physical problems, providing new insights in the Classical
Theory Fields.


title:
Morphometric analysis in gamma-ray astronomy using Minkowski functionals
  - Source detection via structure quantification

abstract:
  Aims. H.E.S.S. observes an increasing number of large extended sources. A new
technique based on the structure of the sky map is developed to account for
these additional structures by comparing them with the common point source
analysis.
  Methods. Minkowski functionals are powerful measures from integral geometry.
They can be used to quantify the structure of the counts map, which is then
compared with the expected structure of a pure Poisson background. Gamma-ray
sources lead to significant deviations from the expected background structure.
The standard likelihood ratio method is exclusively based on the number of
excess counts and discards all further structure information of large extended
sources. The morphometric data analysis incorporates this additional geometric
information in an unbiased analysis, i.e., without the need of any prior
knowledge about the source.
  Results. We have successfully applied our method to data of the H.E.S.S.
experiment. The morphometric analysis presented here is dedicated to detecting
faint extended sources.


title: General Quantum Hilbert Space Modeling Scheme for Entanglement

abstract:
  We work out a classification scheme for quantum modeling in Hilbert space of
any kind of composite entity violating Bell's inequalities and exhibiting
entanglement. Our theoretical framework includes situations with entangled
states and product measurements ('customary quantum situation'), and also
situations with both entangled states and entangled measurements ('nonlocal box
situation', 'nonlocal non-marginal box situation'). We show that entanglement
is structurally a joint property of states and measurements. Furthermore,
entangled measurements enable quantum modeling of situations that are usually
believed to be 'beyond quantum'. Our results are also extended from pure states
to quantum mixtures.


title: Macroscopic quantum spin tunnelling with two interacting spins

abstract:
  We study the simple Hamiltonian, $H=-K(S_{1z}^2 +S_{2z}^2)+ \lambda\vec
S_1\cdot\vec S_2$, of two, large, coupled spins which are taken equal, each of
total spin $s$ with $\lambda$ the exchange coupling constant. The exact ground
state of this simple Hamiltonian is not known for an antiferromagnetic coupling
corresponding to the $\lambda>0$. In the absence of the exchange interaction,
the ground state is four fold degenerate, corresponding to the states where the
individual spins are in their highest weight or lowest weight states,
$|\hskip-1 mm\uparrow, \uparrow\rangle, |\hskip-1 mm\downarrow,
\downarrow\rangle, |\hskip-1 mm\uparrow, \downarrow\rangle, |\hskip-1
mm\downarrow, \uparrow\rangle$, in obvious notation. The first two remain exact
eigenstates of the full Hamiltonian. However, we show the that the two states $
|\hskip-1 mm\uparrow, \downarrow\rangle, |\hskip-1 mm\downarrow,
\uparrow\rangle$ organize themselves into the combinations
$|\pm\rangle=\frac{1}{\sqrt 2} (|\hskip-1 mm\uparrow, \downarrow\rangle \pm
|\hskip-1 mm\downarrow \uparrow\rangle)$, up to perturbative corrections. For
the anti-ferromagnetic case, we show that the ground state is non-degenerate,
and we find the interesting result that for integer spins the ground state is
$|+\rangle$, and the first excited state is the anti-symmetric combination
$|-\rangle$ while for half odd integer spin, these roles are exactly reversed.
The energy splitting however, is proportional to $\lambda^{2s}$, as expected by
perturbation theory to the $2s^{\rm th}$ order. We obtain these results through
the spin coherent state path integral.


title:
Kronoseismology: Using density waves in Saturn's C ring to probe the
  planet's interior

abstract:
  Saturn's C ring contains multiple spiral patterns that appear to be density
waves driven by periodic gravitational perturbations. In other parts of
Saturn's rings, such waves are generated by Lindblad resonances with Saturn's
various moons, but most of the wave-like C-ring features are not situated near
any strong resonance with any known moon. Using stellar occultation data
obtained by the Visual and Infrared Mapping Spectrometer (VIMS) onboard the
Cassini spacecraft, we investigate the origin of six unidentified C-ring waves
located between 80,900 and 87,200 km from Saturn's center. By measuring
differences in the waves' phases among the different occultations, we are able
to determine both the number of arms in each spiral pattern and the speeds at
which these patterns rotate around the planet. We find that all six of these
waves have between 2 and 4 arms and pattern speeds between 1660 degrees/day and
1861 degrees/day. These speeds are too large to be attributed to any satellite
resonance. Instead they are comparable to the predicted pattern speeds of waves
generated by low-order normal-mode oscillations within the planet [Marley &
Porco 1993, Icarus 106, 508]. The precise pattern speeds associated with these
waves should therefore provide strong constraints on Saturn's internal
structure. Furthermore, we identify multiple waves with the same number of arms
and very similar pattern speeds, indicating that multiple m=3 and m=2 sectoral
(l=m) modes may exist within the planet.


title:
Strauss- and Lions-type results for a class of Orlicz-Sobolev spaces and
  applications

abstract:
  The main goal this work is to prove two results like Strauss and Lions for
Orlicz-Sobolev spaces. After, we use these results for study the existence of
solutions for a class of quasilinear problems in $\mathbb{R}^{N}$.


title:
Suppression of Spin-Exchange Relaxation Using Pulsed Parametric
  Resonance

abstract:
  We demonstrate that spin-exchange dephasing of Larmor precession at
near-earth-scale fields is effectively eliminated by dressing the alkali-metal
atom spins in a sequence of AC-coupled 2-pi pulses, repeated at the Larmor
precession frequency. The contribution of spin-exchange collisions to the
spectroscopic line width is reduced by a factor of the duty cycle of the
pulses. We experimentally demonstrate resonant transverse pumping in magnetic
fields as high as 0.1 Gauss, present experimental measurements of the
suppressed spin-exchange relaxation, and show enhanced magnetometer response
relative to a light-narrowed scalar magnetometer.


title: Effects of Epistasis and Pleiotropy on Fitness Landscapes

abstract:
  The factors that influence genetic architecture shape the structure of the
fitness landscape, and therefore play a large role in the evolutionary
dynamics. Here the NK model is used to investigate how epistasis and pleiotropy
-- key components of genetic architecture -- affect the structure of the
fitness landscape, and how they affect the ability of evolving populations to
adapt despite the difficulty of crossing valleys present in rugged landscapes.
Populations are seen to make use of epistatic interactions and pleiotropy to
attain higher fitness, and are not inhibited by the fact that valleys have to
be crossed to reach peaks of higher fitness.


title: An exactly-solvable three-dimensional nonlinear quantum oscillator

abstract:
  Exact analytical, closed-form solutions, expressed in terms of special
functions, are presented for the case of a three-dimensional nonlinear quantum
oscillator with a position dependent mass. This system is the generalization of
the corresponding one-dimensional system, which has been the focus of recent
attention. In contrast to other approaches, we are able to obtain solutions in
terms of special functions, without a reliance upon a Rodrigues-type of
formula. The wave functions of the quantum oscillator have the familiar
spherical harmonic solutions for the angular part. For the s-states of the
system, the radial equation accepts solutions that have been recently found for
the one-dimensional nonlinear quantum oscillator, given in terms of associated
Legendre functions, along with a constant shift in the energy eigenvalues.
Radial solutions are obtained for all angular momentum states, along with the
complete energy spectrum of the bound states.


title:
Frobenius gauges and a new theory of p-torsion sheaves in characteristic
  p. I

abstract:
  We develop a new cohomology theory in characteristic p>0, the so called
F-gauge cohomology, a cohomology with values in the category of so-called
F-gauges, which refines the cristalline cohomology. In this first paper we
mainly discuss the theory for smooth projective varieties over perfect fields
of charatceristic p. We also compare our theory with other existing structures
like the F-zips of Moonen and Wedhorn and the displays of Langer and Zink.


title: Cascade sizes in a branching process with Gamma distributed generations

abstract:
  We derive an exact expression for the probability density function of the
cascade size (total progeny) in a continuous state branching process when the
generations are Gamma distributed. The distribution has application in the
modelling of cascade processes such as landslides and electrical network
failures.


title:
From Cookies to Cooks: Insights on Dietary Patterns via Analysis of Web
  Usage Logs

abstract:
  Nutrition is a key factor in people's overall health. Hence, understanding
the nature and dynamics of population-wide dietary preferences over time and
space can be valuable in public health. To date, studies have leveraged small
samples of participants via food intake logs or treatment data. We propose a
complementary source of population data on nutrition obtained via Web logs. Our
main contribution is a spatiotemporal analysis of population-wide dietary
preferences through the lens of logs gathered by a widely distributed
Web-browser add-on, using the access volume of recipes that users seek via
search as a proxy for actual food consumption. We discover that variation in
dietary preferences as expressed via recipe access has two main periodic
components, one yearly and the other weekly, and that there exist
characteristic regional differences in terms of diet within the United States.
In a second study, we identify users who show evidence of having made an acute
decision to lose weight. We characterize the shifts in interests that they
express in their search queries and focus on changes in their recipe queries in
particular. Last, we correlate nutritional time series obtained from recipe
queries with time-aligned data on hospital admissions, aimed at understanding
how behavioral data captured in Web logs might be harnessed to identify
potential relationships between diet and acute health problems. In this
preliminary study, we focus on patterns of sodium identified in recipes over
time and patterns of admission for congestive heart failure, a chronic illness
that can be exacerbated by increases in sodium intake.


title:
Frequency Transient of Three-Dimensional Perturbations in Shear Flows.
  Similarity Properties and Wave Packets Linear Formation

abstract:
  The present thesis deals with the non-modal linear analysis of 3D
perturbations in wall flows. In the first part,a solution to the Orr-Sommerfeld
and Squire IVP, in the form of orthogonal functions expansion, is researched.
The Galerkin method is successfully implemented to numerically compute
approximate solutions for bounded flows. The Chandrasekhar functions revealed
to ensure a fifth order of accuracy. The focus of the subsequent analysis is on
the transient behavior of the perturbation frequency and phase velocity. The
results confirm recent observations about a jump in the temporal evolution of
the frequency of the wall-normal velocity signal, considered as the end of an
Early Transient. After this jump, the wave frequency for Plane Couette flow
experiences a periodic modulation about the asymptotic value, which is
motivated and investigated in detail. A new result is the presence of a second
frequency jump for the wall-normal vorticity. This fact, together with the
possibility for different values of the signals asymptotic frequency, shows the
existence of an Intermediate Transient. Moreover, a connection between the
frequency jumps and the establishing of a self-similarity condition in time for
both the velocity and vorticity profiles is found and investigated for both
Plane Couette flow and Plane Poiseuille flow. Eventually, through superposition
of waves with limited wavenumber range, a wave packet is reconstructed for
Plane Couette flow and Blasius boundary-layer flow . The linear spot evolution
revealed to have many common features with the early stages of a turbulent
spot, particularly the streaky structure and the spot shape.


title:
Inexact trajectory planning and inverse problems in the
  Hamilton--Pontryagin framework

abstract:
  We study a trajectory-planning problem whose solution path evolves by means
of a Lie group action and passes near a designated set of target positions at
particular times. This is a higher-order variational problem in optimal
control, motivated by potential applications in computational anatomy and
quantum control. Reduction by symmetry in such problems naturally summons
methods from Lie group theory and Riemannian geometry. A geometrically
illuminating form of the Euler-Lagrange equations is obtained from a
higher-order Hamilton-Pontryagin variational formulation. In this context, the
previously known node equations are recovered with a new interpretation as
Legendre-Ostrogradsky momenta possessing certain conservation properties. Three
example applications are discussed as well as a numerical integration scheme
that follows naturally from the Hamilton-Pontryagin principle and preserves the
geometric properties of the continuous-time solution.


title: Towards more accurate clustering method by using dynamic time warping

abstract:
  An intrinsic problem of classifiers based on machine learning (ML) methods is
that their learning time grows as the size and complexity of the training
dataset increases. For this reason, it is important to have efficient
computational methods and algorithms that can be applied on large datasets,
such that it is still possible to complete the machine learning tasks in
reasonable time. In this context, we present in this paper a more accurate
simple process to speed up ML methods. An unsupervised clustering algorithm is
combined with Expectation, Maximization (EM) algorithm to develop an efficient
Hidden Markov Model (HMM) training. The idea of the proposed process consists
of two steps. In the first step, training instances with similar inputs are
clustered and a weight factor which represents the frequency of these instances
is assigned to each representative cluster. Dynamic Time Warping technique is
used as a dissimilarity function to cluster similar examples. In the second
step, all formulas in the classical HMM training algorithm (EM) associated with
the number of training instances are modified to include the weight factor in
appropriate terms. This process significantly accelerates HMM training while
maintaining the same initial, transition and emission probabilities matrixes as
those obtained with the classical HMM training algorithm. Accordingly, the
classification accuracy is preserved. Depending on the size of the training
set, speedups of up to 2200 times is possible when the size is about 100.000
instances. The proposed approach is not limited to training HMMs, but it can be
employed for a large variety of MLs methods.


title: Hot Gas Lines in T Tauri Stars

abstract:
  For Classical T Tauri Stars (CTTSs), the resonance lines of N V, Si IV, and C
IV, as well as the He II 1640 A line, act as diagnostics of the accretion
process. Here we assemble a large high-resolution dataset of these lines in
CTTSs and Weak T Tauri Stars (WTTSs). We present data for 35 stars: one Herbig
Ae star, 28 CTTSs, and 6 WTTSs. We decompose the C IV and He II lines into
broad and narrow Gaussian components (BC & NC). The most common (50 %) C IV
line morphology in CTTSs is that of a low-velocity NC together with a
redshifted BC. The velocity centroids of the BCs and NCs are such that V_BC > 4
* V_NC, consistent with the predictions of the accretion shock model, in at
most 12 out of 22 CTTSs. We do not find evidence of the post-shock becoming
buried in the stellar photosphere due to the pressure of the accretion flow.
The He II CTTSs lines are generally symmetric and narrow, less redshifted than
the CTTSs C IV lines, by ~10 km/sec. The flux in the BC of the He II line is
small compared to that of the C IV line, consistent with models of the
pre-shock column emission. The observations are consistent with the presence of
multiple accretion columns with different densities or with accretion models
that predict a slow-moving, low-density region in the periphery of the
accretion column. For HN Tau A and RW Aur A, most of the C IV line is
blueshifted suggesting that the C IV emission is produced by shocks within
outflow jets. In our sample, the Herbig Ae star DX Cha is the only object for
which we find a P-Cygni profile in the C IV line, which argues for the presence
of a hot (10^5 K) wind. For the overall sample, the Si IV and N V line
luminosities are correlated with the C IV line luminosities, although the
relationship between Si IV and C IV shows large scatter about a linear
relationship and suggests that TW Hya, V4046 Sgr, AA Tau, DF Tau, GM Aur, and
V1190 Sco are silicon-poor.


title: The Social Maintenance of Cooperation through Hypocrisy

abstract:
  Cooperation is widespread in human societies, but its maintenance at the
group level remains puzzling if individuals benefit from not cooperating.
Explanations of the maintenance of cooperation generally assume that
cooperative and non-cooperative behavior in others can be assessed and copied
accurately. However, humans have a well known capacity to deceive and thus to
manipulate how others assess their behavior. Here, we show that hypocrisy -
claiming to be acting cooperatively while acting selfishly - can maintain
social cooperation because it prevents the spread of selfish behavior. We
demonstrate this effect both theoretically and experimentally. Hypocrisy allows
the cooperative strategy to spread by taking credit for the success of the
non-cooperative strategy.


title:
Universal Organization of Resting Brain Activity at the Thermodynamic
  Critical Point

abstract:
  Thermodynamic criticality describes emergent phenomena in a wide variety of
complex systems. In the mammalian brain, the complex dynamics that
spontaneously emerge from neuronal interactions have been characterized as
neuronal avalanches, a form of critical branching dynamics. Here, we show that
neuronal avalanches also reflect that the brain dynamics are organized close to
a thermodynamic critical point. We recorded spontaneous cortical activity in
monkeys and humans at rest using high-density intracranial microelectrode
arrays and magnetoencephalography, respectively. By numerically changing a
control parameter equivalent to thermodynamic temperature, we observed typical
critical behavior in cortical activities near the actual physiological
condition, including the phase transition of an order parameter, as well as the
divergence of susceptibility and specific heat. Finite-size scaling of these
quantities allowed us to derive robust critical exponents highly consistent
across monkey and humans that uncover a distinct, yet universal organization of
brain dynamics.


title:
High-Energy Gamma-Ray Emission From Solar Flares: Summary of Fermi LAT
  Detections and Analysis of Two M-Class Flares

abstract:
  We present the detections of 19 solar flares detected in high-energy gamma
rays (above 100 MeV) with the Fermi Large Area Telescope (LAT) during its first
four years of operation. Interestingly, all flares are associated with fairly
fast Coronal Mass Ejections (CMEs) and are not all powerful X-ray flares. We
then describe the detailed temporal, spatial and spectral characteristics of
the first two long-lasting events: the 2011 March 7 flare, a moderate (M3.7)
impulsive flare followed by slowly varying gamma-ray emission over 13 hours,
and the 2011 June 7 M2.5 flare, which was followed by gamma-ray emission
lasting for 2 hours. We compare the Fermi-LAT data with X-ray and proton data
measurements from GOES and RHESSI. We argue that a hadronic origin of the gamma
rays is more likely than a leptonic origin and find that the energy spectrum of
the proton distribution softens after the 2011 March 7 flare, favoring a
scenario with continuous acceleration at the flare site. This work suggests
that proton acceleration in solar flares is more common than previously
thought, occurring for even modest X-ray flares, and for longer durations.


title: Interaction of a point charge with the surface of a uniaxial dielectric

abstract:
  We analyze the force on a point charge moving at relativistic speeds parallel
to the surface of a uniaxial dielectric. Two cases are examined: a lossless
dielectric with no dispersion and a dielectric with a plasma type response. The
treatment focuses on the peculiarities of the strength and direction of the
interaction force as compared to the isotropic case. We show that a plasma type
dielectric can, under specific conditions, repel the point charge.


title: Minimum Vector Rank and Complement Critical Graphs

abstract:
  Given a graph G, a real orthogonal representation of G is a function from its
set of vertices to R^d such that two vertices are mapped to orthogonal vectors
if and only if they are not neighbors. The minimum vector rank of a graph is
the smallest dimension d for which such a representation exists. This quantity
is closely related to the minimum semidefinite rank of G, which has been widely
studied. Considering the minimum vector rank as an analogue of the chromatic
number, this work defines critical graphs as those for which the removal of any
vertex decreases the minimum vector rank; and complement critical graphs as
those for which the removal of any vertex decreases the minimum vector rank of
either the graph or its complement. It establishes necessary and sufficient
conditions for certain classes of graphs to be complement critical, in the
process calculating their minimum vector rank. In addition, this work
demonstrates that complement critical graphs form a sufficient set to prove the
Graph Complement Conjecture, which remains open.


title:
Reducing assembly complexity of microbial genomes with single-molecule
  sequencing

abstract:
  Background: The short reads output by first- and second-generation DNA
sequencing instruments cannot completely reconstruct microbial chromosomes.
Therefore, most genomes have been left unfinished due to the significant
resources required to manually close gaps in draft assemblies.
Third-generation, single-molecule sequencing addresses this problem by greatly
increasing sequencing read length, which simplifies the assembly problem.
  Results: To measure the benefit of single-molecule sequencing on microbial
genome assembly, we sequenced and assembled the genomes of six bacteria and
analyzed the repeat complexity of 2,267 complete bacteria and archaea. Our
results indicate that the majority of known bacterial and archaeal genomes can
be assembled without gaps, at finished-grade quality, using a single PacBio RS
sequencing library. These single-library assemblies are also more accurate than
typical short-read assemblies and hybrid assemblies of short and long reads.
  Conclusions: Automated assembly of long, single-molecule sequencing data
reduces the cost of microbial finishing to $1,000 for most genomes, and future
advances in this technology are expected to drive the cost lower. This is
expected to increase the number of completed genomes, improve the quality of
microbial genome databases, and enable high-fidelity, population-scale studies
of pan-genomes and chromosomal organization.


title:
Second order viscous corrections to the harmonic spectrum in heavy ion
  collisions

abstract:
  We calculate the second order viscous correction to the kinetic distribution,
$\delta f_{(2)}$, and use this result in a hydrodynamic simulation of heavy ion
collisions to determine the complete second order correction to the harmonic
spectrum, $v_n$. At leading order in a conformal fluid, the first viscous
correction is determined by one scalar function, $\chi_{0p}$. One moment of
this scalar function is constrained by the shear viscosity. At second order in
a conformal fluid, we find that $\delta f(\p)$ can be characterized by two
scalar functions of momentum, $\chi_{1p}$ and $\chi_{2p}$. The momentum
dependence of these functions is largely determined by the kinematics of the
streaming operator. Again, one moment of these functions is constrained by the
parameters of second order hydrodynamics, $\tau_\pi$ and $\lambda_1$. The
effect of $\delta f_{(2)}$ on the integrated flow is small (up to $v_4$), but
is quite important for the higher harmonics at modestly-large $p_T$. Generally,
$\delta f_{(2)}$ increases the value of $v_n$ at a given $p_T$, and is most
important in small systems.


title: Faster Private Release of Marginals on Small Databases

abstract:
  We study the problem of answering \emph{$k$-way marginal} queries on a
database $D \in (\{0,1\}^d)^n$, while preserving differential privacy. The
answer to a $k$-way marginal query is the fraction of the database's records $x
\in \{0,1\}^d$ with a given value in each of a given set of up to $k$ columns.
Marginal queries enable a rich class of statistical analyses on a dataset, and
designing efficient algorithms for privately answering marginal queries has
been identified as an important open problem in private data analysis.
  For any $k$, we give a differentially private online algorithm that runs in
time $$ \min{\exp(d^{1-\Omega(1/\sqrt{k})}), \exp(d / \log^{.99} d)\} $$ per
query and answers any (possibly superpolynomially long and adaptively chosen)
sequence of $k$-way marginal queries up to error at most $\pm .01$ on every
query, provided $n \gtrsim d^{.51} $. To the best of our knowledge, this is the
first algorithm capable of privately answering marginal queries with a
non-trivial worst-case accuracy guarantee on a database of size $\poly(d, k)$
in time $\exp(o(d))$.
  Our algorithms are a variant of the private multiplicative weights algorithm
(Hardt and Rothblum, FOCS '10), but using a different low-weight representation
of the database. We derive our low-weight representation using approximations
to the OR function by low-degree polynomials with coefficients of bounded
$L_1$-norm. We also prove a strong limitation on our approach that is of
independent approximation-theoretic interest. Specifically, we show that for
any $k = o(\log d)$, any polynomial with coefficients of $L_1$-norm $poly(d)$
that pointwise approximates the $d$-variate OR function on all inputs of
Hamming weight at most $k$ must have degree $d^{1-O(1/\sqrt{k})}$.


title:
Near-infrared photometry of Galactic planetary nebulae with the VVV
  Survey

abstract:
  Planetary nebulae (PNe) are powerful tracers of evolved stellar populations.
Among the 3000 known PNe in the Galaxy, about 600 are located within the 520
square-degree area covered by the VVV survey. The VVV photometric catalogue
provides an important new dataset for the study of PNe, with high-resolution
imaging in five near-infrared bands. Aperture photometry of known PNe in the
VVV area was retrieved from source catalogues. Care was taken to minimise any
confusion with field stars. The colours of the PNe we are determined for H-Ks,
J-H, Z-Y, and Y-J, and compared to stars and to other types of emission line
objects. Cloudy photo-ionisation models were used to predict colours for
typical PNe. We present near-infrared photometry for 353 known PNe. The best
separation from other objects is obtained in the H-Ks vs. J-H diagram. We
calculated the emission-line contribution to the in-band flux based on a model
for NGC 6720: we find that this is highest in the Z and Y bands at over 50%,
lower in the J band at 40%, and lowest in the H and Ks bands at 20%. A new view
of PNe in the wavelength domain of the Z and Y bands is shown. Photo-ionisation
models are used to explore the observed colours in these bands. The Y band is
shown to be dominated by HeI 1.083 mu and HeII 1.012 mu, and colours involving
this band are very sensitive to the temperature of the ionizing star. The VVV
survey represents a unique dataset for studing crowded and obscured regions in
the Galactic plane. The diagnostic diagrams presented here allow one to study
the properties of known PNe and to uncover objects not previously classified.


title:
Understanding Compact Object Formation and Natal Kicks. IV. The case of
  IC 10 X-1

abstract:
  The extragalactic X-ray binary IC 10 X-1 has attracted attention as it is
possibly the host of the most massive stellar-mass black-hole (BH) known to
date. Here we consider all available observational constraints and construct
its evolutionary history up to the instant just before the formation of the BH.
Our analysis accounts for the simplest possible history that includes three
evolutionary phases: binary orbital dynamics at core collapse, common envelope
(CE) evolution, and evolution of the BH--helium star binary progenitor of the
observed system. We derive the complete set of constraints on the progenitor
system at various evolutionary stages. Specifically: right before the core
collapse event, we find the mass of the BH immediate progenitor to be > 31 Msun
(at 95% of confidence, same hereafter). The magnitude of the natal kick
imparted to the BH is constrained to be < 130 km/s. Furthermore, we find that
the "enthalpy" formalism recently suggested by Ivanova & Chaichenets is able to
explain the existence of IC 10 X-1 without the need of invoking unreasonably
high CE efficiencies. With this physically motivated formalism, we find that
the CE efficiency required to explain the system is in the range of 0.6--1.


title: Limit operators for circular ensembles

abstract:
  It is known that a unitary matrix can be decomposed into a product of
reflections, one for each dimension, and the Haar measure on the unitary group
pushes forward to independent uniform measures on the reflections. We consider
the sequence of unitary matrices given by successive products of random
reflections.
  In this coupling, we show that powers of the sequence of matrices converge in
a suitable sense to a flow of operators which acts on a random vector space.
The vector space has an explicit description as a subspace of the space of
sequences of complex numbers. The eigenvalues of the matrices converge almost
surely to the eigenvalues of the flow, which are distributed in law according
to a sine-kernel point process. The eigenvectors of the matrices converge
almost surely to vectors which are distributed in law as Gaussian random fields
on a countable set.
  This flow gives the first example of a random operator with a spectrum
distributed according to a sine-kernel point process which is naturally
constructed from finite dimensional random matrix theory.


title: Metrics for Video Quality Assessment in Mobile Scenarios

abstract:
  With exponential increase in the volumes of video traffic in cellular
net-works, there is an increasing need for optimizing the quality of video
delivery. 4G networks (Long Term Evolution Advanced or LTE A) are being
introduced in many countries worldwide, which allow a downlink speed of upto 1
Gbps and uplink of 100 Mbps over a single base station. This makes a strong
push towards video broadcasting over LTE networks, characterizing its
performance and developing metrics which can be deployed to provide user
feedback of video quality and feed-back them to network operators to fine tune
the network. In this paper, we characterize the performance of video
transmission over LTE A physical layer using popular video quality metrics such
as SSIM, Blocking, Blurring, NIQE and BRISQUE. We conduct experiments to find a
suitable no-reference metrics for mobile scenario and find that Blocking
Metrics is most promising in case of channel or modulation variations but it
does not perform well to quantize variations in compression ratios. The metrics
BRISQUE is very efficient in quantizing this distortion and performs well in
case of network variations also.


title:
Bell-CHSH function approach to quantum phase transitions in matrix
  product systems

abstract:
  Recently, nonlocality and Bell inequalities have been used to investigate
quantum phase transitions (QPTs) in low-dimensional quantum systems.
Nonlocality can be detected by the Bell-CHSH function (BCF). In this work, we
extend the study of BCF to the QPTs in matrix product systems (MPSs). In this
kind of QPTs, the ground-state energy keeps analytical in the vicinity of the
QPT points, and is usually called the MPS-QPTs. For several typical models, our
results show that BCF can signal the MPS-QPTs very well. In addition, we find
BCF can capture signal of QPTs in unentangled states and classical states, for
which other measures of quantum correlation (quantum entanglement and quantum
discord) fail. Furthermore, we find that in these MPSs, there exists some kind
of quantum correlation which cannot be characterized by entanglement, or by
nonlocality.


title: Identification of relevant subtypes via preweighted sparse clustering

abstract:
  Cluster analysis methods are used to identify homogeneous subgroups in a data
set. In biomedical applications, one frequently applies cluster analysis in
order to identify biologically interesting subgroups. In particular, one may
wish to identify subgroups that are associated with a particular outcome of
interest. Conventional clustering methods generally do not identify such
subgroups, particularly when there are a large number of high-variance features
in the data set. Conventional methods may identify clusters associated with
these high-variance features when one wishes to obtain secondary clusters that
are more interesting biologically or more strongly associated with a particular
outcome of interest. A modification of sparse clustering can be used to
identify such secondary clusters or clusters associated with an outcome of
interest. This method correctly identifies such clusters of interest in several
simulation scenarios. The method is also applied to a large prospective cohort
study of temporomandibular disorders and a leukemia microarray data set.


title: Excitation of a single atom with exponentially rising light pulses

abstract:
  We investigate the interaction between a single atom and optical pulses in a
coherent state with a controlled temporal envelope. In a comparison between a
rising exponential and a square envelope, we show that the rising exponential
envelope leads to a higher excitation probability for fixed low average photon
numbers, in accordance to a time-reversed Weisskopf-Wigner model. We
characterize the atomic transition dynamics for a wide range of the average
photon numbers, and are able to saturate the optical transition of a single
atom with ~50 photons in a pulse by a strong focusing technique. For photon
numbers of ~1000 in a 15ns long pulse, we clearly observe Rabi oscillations.


title: Evolutionary Turing in the Context of Evolutionary Machines

abstract:
  One of the roots of evolutionary computation was the idea of Turing about
unorganized machines. The goal of this work is the development of foundations
for evolutionary computations, connecting Turing's ideas and the contemporary
state of art in evolutionary computations. To achieve this goal, we develop a
general approach to evolutionary processes in the computational context,
building mathematical models of computational systems, functioning of which is
based on evolutionary processes, and studying properties of such systems.
Operations with evolutionary machines are described and it is explored when
definite classes of evolutionary machines are closed with respect to basic
operations with these machines. We also study such properties as linguistic and
functional equivalence of evolutionary machines and their classes, as well as
computational power of evolutionary machines and their classes, comparing of
evolutionary machines to conventional automata, such as finite automata or
Turing machines.


title: An Improved ACS Algorithm for the Solutions of Larger TSP Problems

abstract:
  Solving large traveling salesman problem (TSP) in an efficient way is a
challenging area for the researchers of computer science. This paper presents a
modified version of the ant colony system (ACS) algorithm called Red-Black Ant
Colony System (RB-ACS) for the solutions of TSP which is the most prominent
member of the combinatorial optimization problem. RB-ACS uses the concept of
ant colony system together with the parallel search of genetic algorithm for
obtaining the optimal solutions quickly. In this paper, it is shown that the
proposed RB-ACS algorithm yields significantly better performance than the
existing best-known algorithms.


title:
Status of non-destructive bunch length measurement based on coherent
  Cherenkov radiation

abstract:
  As a novel non-destructive bunch length diagnostic of the electron beam, an
experimental observation of the coherent Cherenkov radiation generated from a
dielectric caesium iodide crystal with large spectral dispersion was proposed
for the 30MeV femtosecond linear accelerator at Shanghai Institute of Applied
Physics (SINAP). In this paper, the theoretical design, the experimental setup,
the terahertz optics, the first angular distribution observations of the
coherent Cherenkov radiation, and the future plans are presented.


title:
Non-Abelian Majorana Doublets in Time-Reversal Invariant Topological
  Superconductor

abstract:
  The study of non-Abelian Majorana zero modes advances our understanding of
the fundamental physics in quantum matter, and pushes the potential
applications of such exotic states to topological quantum computation. It has
been shown that in two-dimensional (2D) and 1D chiral superconductors, the
isolated Majorana fermions obey non-Abelian statistics. However, Majorana modes
in a $Z_2$ time-reversal invariant (TRI) topological superconductor come in
pairs due to Kramers' theorem. Therefore, braiding operations in TRI
superconductors always exchange two pairs of Majoranas. In this work, we show
interestingly that, due to the protection of time-reversal symmetry,
non-Abelian statistics can be obtained in 1D TRI topological superconductors
and may have advantages in applying to topological quantum computation.
Furthermore, we unveil an intriguing phenomenon in the Josephson effect, that
the periodicity of Josephson currents depends on the fermion parity of the
superconducting state. This effect provides direct measurements of the
topological qubit states in such 1D TRI superconductors.


title: Simultaneous quadrupole and octupole shape phase transitions in Thorium

abstract:
  The evolution of quadrupole and octupole shapes in Th isotopes is studied in
the framework of nuclear Density Functional Theory. Constrained energy maps and
observables calculated with microscopic collective Hamiltonians indicate the
occurrence of a simultaneous quantum shape phase transition between spherical
and quadrupole-deformed prolate shapes, and between non-octupole and
octupole-deformed shapes, as functions of the neutron number. The nucleus
$^{224}$Th is closest to the critical point of a double phase transition. A
microscopic mechanism of this phenomenon is discussed in terms of the evolution
of single-nucleon orbitals with deformation.


title:
A Taxonomy of Performance Assurance Methodologies and its Application in
  High Performance Computer Architectures

abstract:
  This paper presents a systematic approach to the complex problem of high
confidence performance assurance of high performance architectures based on
methods used over several generations of industrial microprocessors. A taxonomy
is presented for performance assurance through three key stages of a product
life cycle-high level performance, RTL performance, and silicon performance.
The proposed taxonomy includes two components-independent performance assurance
space for each stage and a correlation performance assurance space between
stages. It provides a detailed insight into the performance assurance space in
terms of coverage provided taking into account capabilities and limitations of
tools and methodologies used at each stage. An application of the taxonomy to
cases described in the literature and to high performance Intel architectures
is shown. The proposed work should be of interest to manufacturers of high
performance microprocessor/chipset architectures and has not been discussed in
the literature.


title: Nonequilibrium Entropy

abstract:
  We consider an isolated system in an arbitrary state and provide a general
formulation using first principles for an additive and non-negative statistical
quantity that is shown to reproduce the equilibrium thermodynamic entropy of
the isolated system. We further show that the statistical quantity represents
the nonequilibrium thermodynamic entropy when the latter is a state function of
nonequilibrium state variables; see text. We consider an isolated 1-d ideal gas
and determine its non-equilibrium statistical entropy as a function of the box
size as the gas expands freely isoenergetically, and compare it with the
equilibrium thermodynamic entropy S_{0eq}. We find that the statistical entropy
is less than S_{0eq} in accordance with the second law, as expected. To
understand how the statistical entropy is different from thermodynamic entropy
of classical continuum models that is known to become negative under certain
conditions, we calculate it for a 1-d lattice model and discover that it can be
related to the thermodynamic entropy of the continuum 1-d Tonks gas by taking
the lattice spacing {\delta} go to zero, but only if the latter is
state-independent. We discuss the semi-classical approximation of our entropy
and show that the standard quantity S_{f}(t) in the Boltzmann's H-theorem does
not directly correspond to the statistical entropy.


title:
Detection of Gene-Gene Interactions by Multistage Sparse and Low-Rank
  Regression

abstract:
  A daunting challenge faced by modern biological sciences is finding an
efficient and computationally feasible approach to deal with the curse of high
dimensionality. The problem becomes even more severe when the research focus is
on interactions. To improve the performance, we propose a low-rank interaction
model, where the interaction effects are modeled using a low-rank matrix. With
parsimonious parameterization of interactions, the proposed model increases the
stability and efficiency of statistical analysis. Built upon the low-rank
model, we further propose an Extended Screen-and-Clean approach, based on the
Screen and Clean (SC) method (Wasserman and Roeder, 2009; Wu et al., 2010), to
detect gene-gene interactions. In particular, the screening stage utilizes a
combination of a low-rank structure and a sparsity constraint in order to
achieve higher power and higher selection-consistency probability. We
demonstrate the effectiveness of the method using simulations and apply the
proposed procedure on the warfarin dosage study. The data analysis identified
main and interaction effects that would have been neglected using conventional
methods.


title:
Pulsation Analysis of the High Amplitude {\delta} Scuti Star CW
  Serpentis

abstract:
  Time-series photometric observations were made for the High Amplitude
$\delta$ Scuti star CW Ser between 2011 and 2012 at the Xinglong Station of
National Astronomical Observatories of China. After the frequency analysis of
the light curves, we confirmed the fundamental frequency of $f = 5.28677\
cd^{-1}$, together with 8 harmonics of the fundamental frequency, 7 of which
are newly detected. No additional frequencies were detected. The O-C diagram,
produced with the 21 newly determined times of maximum light combined with
those provided in the literature, helps to obtain a new ephemeris formula of
the times of maximum light with the pulsation period of $0.189150355 \pm
0.000000003\ days$.


title: Making I/O Virtualization Easy with Device Files

abstract:
  Personal computers have diverse and fast-evolving I/O devices, making their
I/O virtualization different from that of servers and data centers. In this
paper, we present our recent endeavors in simplifying I/O virtualization for
personal computers. Our key insight is that many operating systems, including
Unix-like ones, abstract I/O devices as device files. There is a small and
stable set of operations on device files, therefore, I/O virtualization at the
device file boundary requires a one-time effort to support various I/O devices.
  We present devirtualization, our design of I/O virtualization at the device
file boundary and its implementation for Linux/x86 systems. We are able to
virtualize various GPUs, input devices, cameras, and audio devices with fewer
than 4900 LoC, of which only about 300 are specific to I/O device classes. Our
measurements show that devirtualized devices achieve interactive performance
indistinguishable from native ones by human users, even when running 3D HD
games.


title: AE Ursae Majoris -- a $\delta$ Scuti Star in the Hertzsprung Gap

abstract:
  We analyze the photometric data and spectroscopic data that collect on the
$\delta$ Scuti star AE UMa. The fundamental and the first overtone frequencies
are confirmed as $f_{0} = 11.62560$\,c\,d$^{-1}$ and $f_{1} =
15.03124$\,c\,d$^{-1}$, respectively, from the frequency content by analyzing
of the 40 nights light curve spanning from 2009 to 2012. Additionally, another
37 frequencies are identified as either the harmonics or the linear
combinations of the fundamental and the first overtone frequencies, among which
25 are newly detected.
  The rate of period change of the fundamental mode is determined as
$(1/P_{0})(dP_{0}/dt) = 5.4(\pm 1.9) \times 10^{-9}$\,yr$^{-1}$ as revealed
from the $O-C$ diagram based on the 84 newly determined times of maximum light
combined with those derived from the literature. The spectroscopic data
suggests that AE UMa is a population\,I $\delta$ Scuti star. With these
physical properties, we perform theoretical explorations based on the stellar
evolution code MESA on this target, considering that the variation of pulsation
period is caused by secular evolutionary effects. We finally constraint the AE
UMa with the physical parameters as: the mass of $1.805 \pm 0.055\ M_{\odot}$,
the radius of $1.647 \pm 0.032 \times 10^{11}$\,cm, the luminosity of $1.381
\pm 0.048~(\log L/L_{\odot})$ and the age of $1.055 \pm 0.095 \times
10^{9}$\,yr. AE UMa can be the (Pop. I) $\delta$ Scuti star that locates just
after the second turn-off of its evolutional track leaving the main sequence, a
star in the phase of the Hertzsprung Gap with a helium core and a
hydrogen-burning shell.


title:
Effects of gravitational confinement on bosonic asymmetric dark matter
  in stars

abstract:
  Considering the existence of old neutron stars puts strong limits on the dark
matter/nucleon cross section for bosonic asymmetric dark matter. Key to these
bounds is formation of a Bose-Einstein condensate (BEC) of the asymmetric dark
matter particles. We consider the effects of the host neutron star's
gravitational field on the BEC transition. We find this substantially shifts
the transition temperature and so strengthens the bounds on cross section. In
particular, for the well-motivated mass range of ~5-15 GeV, we improve previous
bounds by an order of magnitude.


title:
On extremal graphs with at most $\ell$ internally disjoint Steiner trees
  connecting any n-1 vertices

abstract:
  The concept of maximum local connectivity $\bar {\kappa}$ of a graph was
introduced by Bollob\'{a}s. One of the problems about it is to determine the
largest number of edges $f(n;\bar{\kappa}\leq \ell)$ for graphs of order $n$
that have local connectivity at most $\ell$. We consider a generalization of
the above concept and problem. For $S\subseteq V(G)$ and $|S|\geq 2$, the
\emph{generalized local connectivity} $\kappa(S)$ is the maximum number of
internally disjoint trees connecting $S$ in $G$. The parameter
$\bar{\kappa}_k(G)=max\{\kappa(S)|S\subseteq V(G),|S|=k\}$ is called the
\emph{maximum generalized local connectivity} of $G$. This paper it to consider
the problem of determining the largest number $f(n;\bar{\kappa}_k\leq \ell)$ of
edges for graphs of order $n$ that have maximum generalized local connectivity
at most $\ell$. The exact value of $f(n;\bar{\kappa}_k\leq \ell)$ for $k=n,n-1$
is determined. For a general $k$, we construct a graph to obtain a sharp lower
bound.


title: Vertex maps between simplices, cubes, and crosspolytopes

abstract:
  We study the vertices of the polytopes of all affine maps (a.k.a.
hom-polytopes) between higher dimensional simplices, cubes, and crosspolytopes.
Systematic study of general hom-polytopes was initiated in [3]. The study of
such vertices is the classical aspect of a conjectural homological theory of
convex polytopes. One quickly runs into open problems even for simple source
and target polytopes. The vertices of Hom(simplex_m,-) and Hom(-,cube_n) are
easily understood. In this work we describe the vertex sets of
Hom(box_m,simplex_n), Hom(diamond_m,simplex_n), and Hom(diamond_m,diamond_n).
The emergent pattern in our arguments is reminiscent of diagram chasing in
homological algebra.


title: Axial anomaly and the triality symmetry of leptons and hadrons

abstract:
  We apply the supersymmetric model of \'E. Cartan to the pseudoscalar meson
decay into two photons, $\pi_0\to\gamma\gamma$, $\eta\to\gamma\gamma$ and
$\eta'\to\gamma\gamma$. In the book of \'E. Cartan published in 1966, Dirac
spinors ${^t(}A,B)$ and ${^t(}C,D)$ and vector fields $E$ and $E'$ were
introduced and five supersymmetric transformations $G_{23}, G_{12}, G_{13},
G_{123}$ and $G_{132}$ were considered.
  The Pauli spinor is treated as a quaternion and the Dirac spinor is treated
as an octonion. In the pseudoscalar meson decay, when the two final vector
fields belong to the same group ($EE$ or $E'E'$), we call the diagram
rescattering diagram. When they belong to different groups ($EE'$), the diagram
is called twisted diagram.
  Assuming the triality selection rules of octonions, dark matter is
interpreted as matter emitting photons in a different triality sector than that
of electromagnetic probes in our world.


title: On Sun-to-Earth Propagation of Coronal Mass Ejections

abstract:
  We investigate how coronal mass ejections (CMEs) propagate through, and
interact with, the inner heliosphere between the Sun and Earth, a key question
in CME research and space weather forecasting. CME Sun-to-Earth kinematics are
constrained by combining wide-angle heliospheric imaging observations,
interplanetary radio type II bursts and in situ measurements from multiple
vantage points. We select three events for this study, the 2012 January 19, 23,
and March 7 CMEs. Different from previous event studies, this work attempts to
create a general picture for CME Sun-to-Earth propagation and compare different
techniques for determining CME interplanetary kinematics. Key results are
obtained concerning CME Sun-to-Earth propagation. Our comparison between
different techniques (and data sets) also has important implications for CME
observations and their interpretations. Future CME observations and space
weather forecasting are discussed based on these results. See detail in the
PDF.


title:
Optimal Control Theory in Intelligent Transportation Systems Research -
  A Review

abstract:
  Continuous motorization and urbanization around the globe leads to an
expansion of population in major cities. Therefore, ever-growing pressure
imposed on the existing mass transit systems calls for a better technology,
Intelligent Transportation Systems (ITS), to solve many new and demanding
management issues. Many studies in the extant ITS literature attempted to
address these issues within which various research methodologies were adopted.
However, there is very few paper summarized what does optimal control theory
(OCT), one of the sharpest tools to tackle management issues in engineering, do
in solving these issues. It{\textquoteright}s both important and interesting to
answer the following two questions. (1) How does OCT contribute to ITS research
objectives? (2) What are the research gaps and possible future research
directions? We searched 11 top transportation and control journals and reviewed
41 research articles in ITS area in which OCT was used as the main research
methodology. We categorized the articles by four different ways to address our
research questions. We can conclude from the review that OCT is widely used to
address various aspects of management issues in ITS within which a large
portion of the studies aimed to reduce traffic congestion. We also critically
discussed these studies and pointed out some possible future research
directions towards which OCT can be used.


title:
Improving Generalization Ability of Genetic Programming: Comparative
  Study

abstract:
  In the field of empirical modeling using Genetic Programming (GP), it is
important to evolve solution with good generalization ability. Generalization
ability of GP solutions get affected by two important issues: bloat and
over-fitting. Bloat is uncontrolled growth of code without any gain in fitness
and important issue in GP. We surveyed and classified existing literature
related to different techniques used by GP research community to deal with the
issue of bloat. Moreover, the classifications of different bloat control
approaches and measures for bloat are discussed. Next, we tested four bloat
control methods: Tarpeian, double tournament, lexicographic parsimony pressure
with direct bucketing and ratio bucketing on six different problems and
identified where each bloat control method performs well on per problem basis.
Based on the analysis of each method, we combined two methods: double
tournament (selection method) and Tarpeian method (works before evaluation) to
avoid bloated solutions and compared with the results obtained from individual
performance of double tournament method. It was found that the results were
improved with this combination of two methods.


title: Solving the Tower of Hanoi with Random Moves

abstract:
  We prove the exact formulae for the expected number of moves to solve several
variants of the Tower of Hanoi puzzle with 3 pegs and n disks, when each move
is chosen uniformly randomly from the set of all valid moves. We further
present an alternative proof for one of the formulae that couples a theorem
about expected commute times of random walks on graphs with the delta-to-wye
transformation used in the analysis of three-phase AC systems for electrical
power distribution.


title: Black Hole Scattering from Monodromy

abstract:
  We study scattering coefficients in black hole spacetimes using analytic
properties of complexified wave equations. For a concrete example, we analyze
the singularities of the Teukolsky equation and relate the corresponding
monodromies to scattering data. These techniques, valid in full generality,
provide insights into complex-analytic properties of greybody factors and
quasinormal modes. This leads to new perturbative and numerical methods which
are in good agreement with previous results.


title:
The UK Infrared Telescope M33 monitoring project. III. Feedback from
  dusty stellar winds in the central square kiloparsec

abstract:
  We have conducted a near-infrared monitoring campaign at the UK InfraRed
Telescope (UKIRT), of the Local Group spiral galaxy M33 (Triangulum). The main
aim was to identify stars in the very final stage of their evolution, and for
which the luminosity is more directly related to the birth mass than the more
numerous less-evolved giant stars that continue to increase in luminosity. In
this third paper of the series, we measure the dust production and rates of
mass loss by the pulsating Asymptotic Giant Branch (AGB) stars and red
supergiants. To this aim, we combined our time-averaged near-IR photometry with
the multi-epoch mid-IR photometry obtained with the Spitzer Space Telescope.
The mass-loss rates are seen to increase with increasing strength of pulsation
and with increasing bolometric luminosity. Low-mass stars lose most of their
mass through stellar winds, but even super-AGB stars and red supergiants lose
$\sim40$% of their mass via a dusty stellar wind. More than three-quarters of
the dust return is oxygenous. We construct a 2-D map of the mass-return rate,
showing a radial decline but also local enhancements due to agglomerations of
massive stars. We estimate a total mass-loss rate of 0.004--0.005 M$_\odot$
yr$^{-1}$ kpc$^{-2}$, increasing to $\sim0.006$ M$_\odot$ yr$^{-1}$ kpc$^{-2}$
when accounting for eruptive mass loss (e.g., supernov{\ae}); comparing this to
the current star formation rate of $\sim0.03$ M$_\odot$ yr$^{-1}$ kpc$^{-2}$ we
conclude that star formation in the central region of M\,33 can only be
sustained if gas is accreted from further out in the disc or from
circum-galactic regions.


title: Face numbers of Engstr\"om representations of matroids

abstract:
  A classic problem in matroid theory is to find subspace arrangements,
specifically hyperplane and pseudosphere arrangements, whose intersection
posets are isomorphic to a prescribed geometric lattice. Engstr\"om recently
showed how to construct an infinite family of such subspace arrangements,
indexed by the set of finite regular CW complexes. In this note, we compute the
face numbers of these representations (in terms of the face numbers of the
indexing complexes) and give upper bounds on the total number of faces in these
objects. In particular, we show that, for a fixed rank, the total number of
faces in the Engstr\"om representation corresponding to a codimension one
homotopy sphere arrangement is bounded above by a polynomial in the number of
elements of the matroid with degree one less than its rank.


title: Homotopy invariance of higher K-theory for abelian categories

abstract:
  The main theorem in this paper is that the base change functor from a
noetherian abelian category to its noetherian polynomial category induces an
isomorphism on K-theory. The main theorem implies the well-known fact that
A^1-homotopy invariance of K'-theory for noetherian schemes.


title: Intrinsic high-temperature superconductivity in ternary iron selenides

abstract:
  We examine superconductivity in the mesoscopically mixed
antiferromagnetic(AF) and superconducting (SC) phases of ternary iron selenides
K$_{y}$Fe$_{2-x}$Se$_{2}$. It is shown that the interlayer hopping and AF order
are key factors to determine $T_{c}$ of the SC phase. In general, the hopping
will produce deformed Fermi surfaces (FS's) that tend to suppress
superconductivity. However, contrary to the common expectation, we find that
larger AF order actually results in larger SC order, which explains the
observed relatively high $T_{c}$ in these phases. Furthermore our results
indicate that by reducing the interlayer hopping appropriately, phase-separated
K$_{y}$Fe$_{2-x}$Se$_{2}$ may exhibit its intrinsic SC phase in the two
dimensional limit with a much higher $T_{c}$ ($\sim 65K$) than what has been
observed.


title: Stochastic Modelling of T-Cell-Activation

abstract:
  We investigate a special part of the human immune system, namely the
activation of T-Cells, using stochastic tools, especially sharp large deviation
results. T-Cells have to distinguish reliably between foreign and self peptides
which are both presented to them by antigen presenting cells. Our work is based
on a model studied by Zint, Baake, and den Hollander, and originally proposed
by van den Berg, Rand, and Burroughs. We are able to dispense with some
restrictive distribution assumptions that were used previously, i.e. we
establish a higher robustness of the model. A central issue is the analysis of
two new perspectives to the scenario (two different quenched systems) in
detail. This means that we do not only analyse the total probability of a
T-Cell activation (the annealed case) but also consider the probability of an
activation of one certain T-Cell type and the probability of a T-Cell
activation by a certain antigen presenting cell (the quenched cases). Finally,
we see analytically that the probability of T-Cell activation increases with
the number of presented foreign peptides in all three cases.


title:
Fractal structure of near-threshold quarkonium production off cold
  nuclear matter

abstract:
  We investigate near-threshold production of quarkonium resonances in cold
nuclear matter through a scaling theory with two exponents which are fixed by
existing data on near-threshold J/psi production in proton-nucleus collisions.
Interestingly, it seems possible to extend one of the multifractal dimensions
to the production of other mesons in cold nuclear matter. The scaling theory
can be tested and refined in experiments at the upcoming high-intensity FAIR
accelerator complex in GSI.


title:
A second-order numerical method for two-dimensional two-sided space
  fractional convection diffusion equation

abstract:
  Space fractional convection diffusion equation describes physical phenomena
where particles or energy (or other physical quantities) are transferred inside
a physical system due to two processes: convection and superdiffusion. In this
paper, we discuss the practical alternating directions implicit method to solve
the two-dimensional two-sided space fractional convection diffusion equation on
a finite domain. We theoretically prove and numerically verify that the
presented finite difference scheme is unconditionally von Neumann stable and
second order convergent in both space and time directions.


title:
Detection of atomic spin labels in a lipid bi-layer using a single-spin
  nanodiamond probe

abstract:
  Magnetic field fluctuations arising from fundamental spins are ubiquitous in
nanoscale biology, and are a rich source of information about the processes
that generate them. However, the ability to detect the few spins involved
without averaging over large ensembles has remained elusive. Here we
demonstrate the detection of gadolinium spin labels in an artificial cell
membrane under ambient conditions using a single-spin nanodiamond sensor.
Changes in the spin relaxation time of the sensor located in the lipid bilayer
were optically detected and found to be sensitive to near-individual proximal
gadolinium atomic labels. The detection of such small numbers of spins in a
model biological setting, with projected detection times of one second, opens a
new pathway for in-situ nanoscale detection of dynamical processes in biology.


title: Global strong solution to Maxwell-Dirac equations in 1+1 dimensions

abstract:
  The Maxwell-Dirac equations with nonzero charge mass in one space dimension
are studied under the Lorentz gauge condition. The global existence and
uniqueness of solution in $C([0,+\infty);L^2(R^1))\times C_b(R^1 \times
[0,\infty))$ for initial value problem of Maxwell-Dirac equations are proved.


title:
Universality in s-wave and higher partial wave Feshbach resonances: an
  illustration with a single atom near two scattering centers

abstract:
  It is well-known that cold atoms near s-wave Feshbach resonances have
universal properties that are insensitive to the short-range details of the
interaction. What is less known is that atoms near higher partial wave Feshbach
resonances also have remarkable universal properties. We illustrate this with a
single atom interacting resonantly with two fixed static centers. At a Feshbach
resonance point with orbital angular momentum $L\ge1$, we find $2L+1$ shallow
bound states whose energies behave like $1/R^{2L+1}$ when the distance $R$
between the two centers is large. We then compute corrections to the binding
energies due to other parameters in the effective range expansions. For
completeness we also compute the binding energies near s-wave Feshbach
resonances, taking into account the corrections. Afterwards we turn to the
bound states at large but finite scattering volumes. For p-wave and higher
partial wave resonances, we derive a simple formula for the energies in terms
of a parameter called "proximity parameter". These results are applicable to a
free atom interacting resonantly with two atoms that are localized to two
lattice sites of an optical lattice, and to one light atom interacting with two
heavy ones in free space. Modifications of the low energy physics due to the
long range Van der Waals potential are also discussed.


title:
Solving Linear Equations Using a Jacobi Based Time-Variant Adaptive
  Hybrid Evolutionary Algorithm

abstract:
  Large set of linear equations, especially for sparse and structured
coefficient (matrix) equations, solutions using classical methods become
arduous. And evolutionary algorithms have mostly been used to solve various
optimization and learning problems. Recently, hybridization of classical
methods (Jacobi method and Gauss-Seidel method) with evolutionary computation
techniques have successfully been applied in linear equation solving. In the
both above hybrid evolutionary methods, uniform adaptation (UA) techniques are
used to adapt relaxation factor. In this paper, a new Jacobi Based Time-Variant
Adaptive (JBTVA) hybrid evolutionary algorithm is proposed. In this algorithm,
a Time-Variant Adaptive (TVA) technique of relaxation factor is introduced
aiming at both improving the fine local tuning and reducing the disadvantage of
uniform adaptation of relaxation factors. This algorithm integrates the Jacobi
based SR method with time variant adaptive evolutionary algorithm. The
convergence theorems of the proposed algorithm are proved theoretically. And
the performance of the proposed algorithm is compared with JBUA hybrid
evolutionary algorithm and classical methods in the experimental domain. The
proposed algorithm outperforms both the JBUA hybrid algorithm and classical
methods in terms of convergence speed and effectiveness.


title:
Light output response of the LVD liquid scintillator to neutron-induced
  nuclear recoils

abstract:
  The organic liquid scintillator used in the LVD experiment (INFN Gran Sasso
National Laboratory) has been exposed to an Am-Be neutron source to measure the
light response function for neutron energies in the region from about 4 to 11
MeV. A full Monte Carlo simulation, incorporating the detector response, is
used to generate neutron scattering spectra which are matched to the observed
ones to determine the quenching factors. The obtained light output response is
well described by the semi-empirical Birks model. The results, consistent with
those obtained by other authors using similar hydrocarbonate scintillators, can
be of interest for fast and high-energy neutron spectroscopy that could be
performed with this detector.


title: Positive Lyapunov exponents for Hamiltonian linear differential systems

abstract:
  In the present paper we give a positive answer to some questions posed by
Viana on the existence of positive Lyapunov exponents for Hamiltonian linear
differential systems. We prove that there exists an open and dense set of
Hamiltonian linear differential systems, over a suspension flow with bounded
roof function, displaying at least one positive Lyapunov exponent. In
consequence, typical cocycles over a uniformly hyperbolic flow are chaotic.
Finally, we obtain similar results for cocycles over flows preserving an
ergodic, hyperbolic measure with local product structure.


title: An Investigation of Wavelet Packet Transform for Spectrum Estimation

abstract:
  In this article, we investigate the application of wavelet packet transform
as a novel spectrum sensing approach. The main attraction for wavelet packets
is the tradeoffs they offer in terms of satisfying various performance metrics
such as frequency resolution, variance of the estimated power spectral density
(PSD) and complexity. The results of the experiments show that the wavelet
based approach offers great flexibility, reconfigure ability and adaptability
apart from its performances which are comparable and at times even better than
Fourier based estimates.


title:
Nodes having a major influence to break cooperation define a novel
  centrality measure: game centrality

abstract:
  Cooperation played a significant role in the self-organization and evolution
of living organisms. Both network topology and the initial position of
cooperators heavily affect the cooperation of social dilemma games. We
developed a novel simulation program package, called 'NetworGame', which is
able to simulate any type of social dilemma games on any model, or real world
networks with any assignment of initial cooperation or defection strategies to
network nodes. The ability of initially defecting single nodes to break overall
cooperation was called as 'game centrality'. The efficiency of this measure was
verified on well-known social networks, and was extended to 'protein games',
i.e. the simulation of cooperation between proteins, or their amino acids. Hubs
and in particular, party hubs of yeast protein-protein interaction networks had
a large influence to convert the cooperation of other nodes to defection.
Simulations on methionyl-tRNA synthetase protein structure network indicated an
increased influence of nodes belonging to intra-protein signaling pathways on
breaking cooperation. The efficiency of single, initially defecting nodes to
convert the cooperation of other nodes to defection in social dilemma games may
be an important measure to predict the importance of nodes in the integration
and regulation of complex systems. Game centrality may help to design more
efficient interventions to cellular networks (in forms of drugs), to ecosystems
and social networks. The NetworGame algorithm is downloadable from here:
www.NetworGame.linkgroup.hu

categories: q-bio.MN cs.GT cs.SI nlin.AO physics.soc-ph


title:
Uniform BMO estimate of parabolic equations and global well-posedness of
  the thermistor problem

abstract:
  Global well-posedness of the time-dependent (degenerate) thermistor problem
remains open for many years. In this paper, we solve the problem by
establishing a uniform-in-time BMO estimate of inhomogeneous parabolic
equations. Applying this estimate to the temperature equation, we derive a BMO
bound of the temperature uniform with respect to time, which implies that the
electric conductivity is a $A_2$ weight. The H\"{o}lder continuity of the
electric potential is then proved by applying the De Giorgi--Nash--Moser
estimate for degenerate elliptic equations with $A_2$ coefficient. Uniqueness
of solution is proved based on the established regularity of the weak solution.
Our results also imply the existence of a global classical solution when the
initial and boundary data are smooth.


title: Parametric survey of longitudinal prominence oscillation simulations

abstract:
  It is found that both microflare-sized impulsive heating at one leg of the
loop and a suddenly imposed velocity perturbation can propel the prominence to
oscillate along the magnetic dip. An extensive parameter survey results in a
scaling law, showing that the period of the oscillation, which weakly depends
on the length and height of the prominence, and the amplitude of the
perturbations, scales with $\sqrt{R/g_\odot}$, where $R$ represents the
curvature radius of the dip, and $g_\odot$ is the gravitational acceleration of
the Sun. This is consistent with the linear theory of a pendulum, which implies
that the field-aligned component of gravity is the main restoring force for the
prominence longitudinal oscillations, as confirmed by the force analysis.
However, the gas pressure gradient becomes non-negligible for short
prominences. The oscillation damps with time in the presence of non-adiabatic
processes. Compared to heat conduction, the radiative cooling is the dominant
factor leading to the damping. A scaling law for the damping timescale is
derived, i.e., $\tau\sim l^{1.63} D^{0.66}w^{-1.21}v_{0}^{-0.30}$, showing
strong dependence on the prominence length $l$, the geometry of the magnetic
dip (characterized by the depth $D$ and the width $w$), and the velocity
perturbation amplitude $v_0$. The larger the amplitude, the faster the
oscillation damps. It is also found that mass drainage significantly reduces
the damping timescale when the perturbation is too strong.


title:
Skew polynomial algebras with coefficients in Koszul Artin-Schelter
  regular algebras

abstract:
  Let $A$ be a Koszul Artin-Schelter regular algebra with Nakayama automorphism
$\xi$. We show that the Yoneda Ext-algebra of the skew polynomial algebra
$A[z;\xi]$ is a trivial extension of a Frobenius algebra. Then we prove that
$A[z;\xi]$ is Calabi-Yau; and hence each Koszul Artin Schelter regular algebra
is a subalgebra of a Koszul Calabi-Yau algebra. A superpotential $\hat{w}$ is
also constructed so that the Calabi-Yau algebra $A[z;\xi]$ is isomorphic to the
derivation quotient of $\hat{w}$. The Calabi-Yau property of a skew polynomial
algebra with coefficients in a PBW-deformation of a Koszul Artin-Schelter
regular algebra is also discussed.


title: Extremely efficient generation of Gamma random variables for \alpha >= 1

abstract:
  The Gamma distribution is well-known and widely used in many signal
processing and communications applications. In this letter, a simple and
extremely efficient accept/reject algorithm is introduced for the generation of
independent random variables from a Gamma distribution with any shape parameter
\alpha >= 1. The proposed method uses another Gamma distribution with integer
\alpha_p <= \alpha, from which samples can be easily drawn, as proposal
function. For this reason, the new technique attains a higher acceptance rate
(AR) for \alpha >= 3 than all the methods currently available in the
literature, with AR tends to 1 as \alpha\ diverges.


title: Essential Spectra of Linear Relations

abstract:
  Five essential spectra of linear relations are defined in terms of
semi-Fredholm properties and the index. Basic properties of these sets are
established and the perturbation theory for semi-Fredholm relations is then
applied to verify a generalisation of Weyl's theorem for single-valued
operators. We conclude with a spectral mapping theorem.


title: Spectral triples and KK-theory: A survey

abstract:
  This survey deals with the construction of a category of spectral triples
that is compatible with the Kasparov product in $KK$-theory. These notes serve
as an intuitive guide to these results, avoiding the necessary technical
proofs. We will also add some background and a broader perspective on
noncommutative geometry.


title: The Fate of Monsters in Anti-de Sitter Spacetime

abstract:
  Black hole entropy remains a deep puzzle: where does such enormous amount of
entropy come from? Curiously, there exist gravitational configurations that
possess even larger entropy than a black hole of the same mass, in fact,
arbitrarily high entropy. These are the so-called monsters, which are
problematic to the Anti-de Sitter/Conformal Field Theory (AdS/CFT)
correspondence paradigm since there is far insufficient degrees of freedom on
the field theory side to account for the enormous entropy of monsters in AdS
bulk. The physics of the bulk however may be considerably modified at
semi-classical level due to the presence of branes. We show that this is
especially so since monster spacetimes are unstable due to brane nucleation. As
a consequence, it is not clear what the final fate of monsters is. We argue
that in some cases there is no real threat from monsters since although they
are solutions to Einstein's Field Equations, they are very likely to be
completely unstable when embedded in string theory, and thus probably are not
solutions to the full quantum theory of gravity. Our analysis, while suggestive
and supportive of the claim that such pathological objects are not allowed in
the final theory, by itself does not rule out all monsters. We comment on
various kin of monsters such as the bag-of-gold spacetime, and also discuss
briefly the implications of our work to some puzzles related to black hole
entropy.


title: Multithreaded Input-Sensitive Profiling

abstract:
  Input-sensitive profiling is a recent performance analysis technique that
makes it possible to estimate the empirical cost function of individual
routines of a program, helping developers understand how performance scales to
larger inputs and pinpoint asymptotic bottlenecks in the code. A current
limitation of input-sensitive profilers is that they specifically target
sequential computations, ignoring any communication between threads. In this
paper we show how to overcome this limitation, extending the range of
applicability of the original approach to multithreaded applications and to
applications that operate on I/O streams. We develop new metrics for
automatically estimating the size of the input given to each routine
activation, addressing input produced by non-deterministic memory stores
performed by other threads as well as by the OS kernel (e.g., in response to
I/O or network operations). We provide real case studies, showing that our
extension allows it to characterize the behavior of complex applications more
precisely than previous approaches. An extensive experimental investigation on
a variety of benchmark suites (including the SPEC OMP2012 and the PARSEC
benchmarks) shows that our Valgrind-based input-sensitive profiler incurs an
overhead comparable to other prominent heavyweight analysis tools, while
collecting significantly more performance points from each profiling session
and correctly characterizing both thread-induced and external input.


title:
Stability theory for difference approximations of some dispersive
  shallow water equations and application to thin film flows

abstract:
  In this paper, we study the stability of various difference approximations of
the Euler-Korteweg equations. This system of evolution PDEs is a classical
isentropic Euler system perturbed by a dispersive (third order) term. The Euler
equations are discretized with a classical scheme (e.g. Roe, Rusanov or
Lax-Friedrichs scheme) whereas the dispersive term is discretized with centered
finite differences. We first prove that a certain amount of numerical viscosity
is needed for a difference scheme to be stable in the Von Neumann sense. Then
we consider the entropy stability of difference approximations. For that
purpose, we introduce an additional unknown, the gradient of a function of the
density. The Euler-Korteweg system is transformed into a hyperbolic system
perturbed by a second order skew symmetric term. We prove entropy stability of
Lax-Friedrichs type schemes under a suitable Courant-Friedrichs-Levy condition.
We validate our approach numerically on a simple case and then carry out
numerical simulations of a shallow water system with surface tension which
models thin films down an incline. In addition, we propose a spatial
discretization of the Euler-Korteweg system seen as a Hamiltonian system of
evolution PDEs. This spatial discretization preserves the Hamiltonian structure
and thus is naturally entropy conservative. This scheme makes possible the
numerical simulation of the dispersive shock waves of the Euler Korteweg
system.


title: Localization Formulas About Two Killing Vector Fields

abstract:
  In this article, we will discuss the smooth
$(X_{M}+\sqrt{-1}Y_{M})$-invariant forms on $M$ and to establish a localization
formulas. As an application, we get a localization formulas for characteristic
numbers.


title: Lattice Study of Radiative $J/\psi$ Decay to a Tensor Glueball

abstract:
  The radiative decay of $J/\psi$ into a pure gauge tensor glueball is studied
in the quenched lattice QCD formalism. With two anisotropic lattices, the
mutlipole amplitudes E_1(0), M_2(0) and E_3(0) are obtained to be
0.114(12)(6)GeV, -0.011(5)(1)GeV, and 0.023(8)(1)GeV, respectively. The first
error comes from the statistics, the Q^2 interpolation, and the continuum
extrapolation, while the second is due to the uncertainty of the scale
parameter r_0^{-1}=410(20) MeV. Thus the partial decay width
$\Gamma(J/\psi\rightarrow \gamma G_{2^{++}})$ is estimated to be 1.01(22)(10)
keV which corresponds to a large branch ratio 1.1(2)(1)x10^{-2}. The
phenomenological implication of this result is also discussed.


title:
Spin vortices, skyrmions and the Kosterlitz-Thouless transition in the
  two-dimensional antiferromagnet

abstract:
  We investigate spin-vortex excitations in the two-dimensional antiferromagnet
on the basis of the nonlinear sigma model. The model of two-dimensional
Heisenberg quantum antiferromagnet is mapped onto the (2+1)D nonlinear sigma
model. The 2D nonlinear sigma model has an instanton (or skyrmion) solution
which describes an excitation of spin-vortex type. Quantum fluctuations of
instantons are reduced to the study of the Coulomb gas, and the gas of
instantons of the 2D nonlinear sigma model is in the plasma phase. We
generalize this picture of instanton gas to the (2+1)D nonlinear sigma model.
We show, using some approximation, that there is a Kosterlitz-Thouless
transition from the plasma phase to the molecular phase as the temperature is
lowered.


title: Structure formation of surfactant membranes under shear flow

abstract:
  Shear-flow-induced structure formation in surfactant-water mixtures is
investigated numerically using a meshless-membrane model in combination with a
particle-based hydrodynamics simulation approach for the solvent. At low shear
rates, uni-lamellar vesicles and planar lamellae structures are formed at small
and large membrane volume fractions, respectively. At high shear rates,
lamellar states exhibit an undulation instability, leading to rolled or
cylindrical membrane shapes oriented in the flow direction. The spatial
symmetry and structure factor of this rolled state agree with those of
intermediate states during lamellar-to-onion transition measured by
time-resolved scatting experiments. Structural evolution in time exhibits a
moderate dependence on the initial condition.


title: Lepton-number violating four-body decays of heavy mesons

abstract:
  Neutrinoless hadron Lepton Number Violating (LNV) decays can be induced by
virtual Majorana neutrino, which in turn indubitably show the Majorana nature
of neutrinos. Many three-body LNV processes and Lepton Flavour Violating (LFV)
processes have been studied extensively in theory and by experiment. As a
supplement, we here study 75 four-body LNV (LFV) processes from heavy
pseudoscalar $B$ and $D$ decays. Most of these processes have not been studied
in theory and searched for in experiment, while they may have sizable decay
rates. Since the four-body decay modes have the same vertexes and mixing
parameters with three-body cases, so their branching fractions are comparable
with the corresponding three-body decays. We calculate their decay widths and
branching fractions with current bounds on heavy Majorana neutrino mixing
parameters, and estimate some channels' reconstruction events using the current
experimental data from Belle.


title: Tate Cycles on Abelian Varieties with Complex Multiplication

abstract:
  We consider Tate cycles on an Abelian variety $A$ defined over a sufficiently
large number field $K$ and having complex multiplication. We show that there is
an effective bound $C = C(A,K)$ so that to check whether a given cohomology
class is a Tate class on $A$, it suffices to check the action of Frobenius
elements at primes $v$ of norm $ \leq C$. We also show that for a set of primes
$v$ of $K$ of density 1, the space of Tate cycles on the special fibre $A_v$ of
the N\'eron model of $A$ is isomorphic to the space of Tate cycles on $A$
itself.


title: Time-Optimal Interactive Proofs for Circuit Evaluation

abstract:
  Recently, researchers have been working toward the development of practical
general-purpose protocols for verifiable computation. These protocols enable a
computationally weak verifier to offload computations to a powerful but
untrusted prover, while providing the verifier with a guarantee that the prover
performed the computations correctly. Despite substantial progress, existing
implementations are not yet practical. The main bottleneck is typically the
extra effort required by the prover to return an answer with a guarantee of
correctness, compared to returning an answer with no guarantee.
  We describe a refinement of a powerful interactive proof protocol originally
due to Goldwasser, Kalai, and Rothblum. Cormode, Mitzenmacher, and Thaler show
how to implement the prover in this protocol in time O(S log S), where S is the
size of an arithmetic circuit computing the function of interest. Our
refinements apply to circuits whose wiring pattern is sufficiently "regular";
for these circuits, we bring the runtime of the prover down to O(S). That is,
our prover can evaluate the circuit with a guarantee of correctness, with only
a constant-factor blowup in work compared to evaluating the circuit with no
guarantee.
  We argue that our refinements capture a large class of circuits, and prove
some theorems formalizing this. Experimentally, our refinements yield a 200x
speedup for the prover over the implementation of Cormode et al., and our
prover is less than 10x slower than a C++ program that simply evaluates the
circuit. Along the way, we describe a special-purpose protocol for matrix
multiplication that is of interest in its own right.
  Our final contribution is a protocol targeted at general data parallel
computation. Compared to prior work, this protocol can more efficiently verify
complicated computations as long as that computation is applied independently
to many pieces of data.


title:
Remark on the paper "Eigenvalues of the Witten-Laplacian on compact
  Riemannian manifolds" Q.-M. Cheng and L. Zeng [arXiv:1304.3212]

abstract:
  Why the results of that article [arXiv:1304.3212] are immediate consequences
of known ones.


title:
Measuring the default risk of sovereign debt from the perspective of
  network

abstract:
  Recently, there has been a growing interest in network research, especially
in these fields of biology, computer science, and sociology. It is natural to
address complex financial issues such as the European sovereign debt crisis
from the perspective of network. In this article, we construct a network model
according to the debt--credit relations instead of using the conventional
methodology to measure the default risk. Based on the model, a risk index is
examined using the quarterly report of consolidated foreign claims from the
Bank for International Settlements (BIS) and debt/GDP ratios among these
reporting countries. The empirical results show that this index can help the
regulators and practitioners not only to determine the status of
interconnectivity but also to point out the degree of the sovereign debt
default risk. Our approach sheds new light on the investigation of quantifying
the systemic risk.


title:
Femtoscopic scales in $p+p$ and $p+$Pb collisions in view of the
  uncertainty principle

abstract:
  A method for quantum corrections of Hanbury-Brown/Twiss (HBT) interferometric
radii produced by semi-classical event generators is proposed. These
corrections account for the basic indistinguishability and mutual coherence of
closely located emitters caused by the uncertainty principle. A detailed
analysis is presented for pion interferometry in $p+p$ collisions at LHC energy
($\sqrt{s}=7$ TeV). A prediction is also presented of pion interferometric
radii for $p+$Pb collisions at $\sqrt{s}=5.02$ TeV. The
hydrodynamic/hydrokinetic model with UrQMD cascade as 'afterburner' is utilized
for this aim. It is found that quantum corrections to the interferometry radii
improve significantly the event generator results which typically overestimate
the experimental radii of small systems. A successful description of the
interferometry structure of $p+p$ collisions within the corrected hydrodynamic
model requires the study of the problem of thermalization mechanism, still a
fundamental issue for ultrarelativistic $A+A$ collisions, also for high
multiplicity $p+p$ and $p+$Pb events.


title: Annotations for Sparse Data Streams

abstract:
  Motivated by cloud computing, a number of recent works have studied annotated
data streams and variants thereof. In this setting, a computationally weak
verifier (cloud user), lacking the resources to store and manipulate his
massive input locally, accesses a powerful but untrusted prover (cloud
service). The verifier must work within the restrictive data streaming
paradigm. The prover, who can annotate the data stream as it is read, must not
just supply the answer but also convince the verifier of its correctness.
Ideally, both the amount of annotation and the space used by the verifier
should be sublinear in the relevant input size parameters.
  A rich theory of such algorithms -- which we call schemes -- has emerged.
Prior work has shown how to leverage the prover's power to efficiently solve
problems that have no non-trivial standard data stream algorithms. However,
while optimal schemes are now known for several basic problems, such optimality
holds only for streams whose length is commensurate with the size of the data
universe. In contrast, many real-world datasets are relatively sparse,
including graphs that contain only O(n^2) edges, and IP traffic streams that
contain much fewer than the total number of possible IP addresses, 2^128 in
IPv6.
  We design the first schemes that allow both the annotation and the space
usage to be sublinear in the total number of stream updates rather than the
size of the data universe. We solve significant problems, including variations
of INDEX, SET-DISJOINTNESS, and FREQUENCY-MOMENTS, plus several natural
problems on graphs. On the other hand, we give a new lower bound that, for the
first time, rules out smooth tradeoffs between annotation and space usage for a
specific problem. Our technique brings out new nuances in Merlin-Arthur
communication complexity models, and provides a separation between online
versions of the MA and AMA models.


title:
Structural properties of fluids interacting via piece-wise constant
  potentials with a hard core

abstract:
  The structural properties of fluids whose molecules interact via potentials
with a hard core plus two piece-wise constant sections of different widths and
heights are presented. These follow from the more general development
previously introduced for potentials with a hard core plus $n$ piece-wise
constant sections [Condens. Matter Phys. {\bf 15}, 23602 (2012)] in which use
was made of a semi-analytic rational-function approximation method. The results
of illustrative cases comprising eight different combinations of wells and
shoulders are compared both with simulation data and with those that follow
from the numerical solution of the Percus-Yevick and hypernetted-chain integral
equations. It is found that the rational-function approximation generally
predicts a more accurate radial distribution function than the Percus-Yevick
theory and is comparable or even superior to the hypernetted-chain theory. This
superiority over both integral equation theories is lost, however, at high
densities, especially as the widths of the wells and/or the barriers increase.


title: The Persistent Activity of Jupiter-Family Comets at 3 to 7 AU

abstract:
  We present an analysis of comet activity based on the Spitzer Space Telescope
component of the Survey of the Ensemble Physical Properties of Cometary Nuclei.
We show that the survey is well suited to measuring the activity of
Jupiter-family comets at 3-7 AU from the Sun. Dust was detected in 33 of 89
targets (37 +/- 6%), and we conclude that 21 comets (24 +/- 5%) have
morphologies that suggest ongoing or recent cometary activity. Our dust
detections are sensitivity limited, therefore our measured activity rate is
necessarily a lower limit. All comets with small perihelion distances (q < 1.8
AU) are inactive in our survey, and the active comets in our sample are
strongly biased to post-perihelion epochs. We introduce the quantity
epsilon-f-rho, intended to be a thermal emission counterpart to the often
reported A-f-rho, and find that the comets with large perihelion distances
likely have greater dust production rates than other comets in our survey at
3-7 AU from the Sun, indicating a bias in the discovered Jupiter-family comet
population. By examining the orbital history of our survey sample, we suggest
that comets perturbed to smaller perihelion distances in the past 150 yr are
more likely to be active, but more study on this effect is needed.


title:
SybilFence: Improving Social-Graph-Based Sybil Defenses with User
  Negative Feedback

abstract:
  Detecting and suspending fake accounts (Sybils) in online social networking
(OSN) services protects both OSN operators and OSN users from illegal
exploitation. Existing social-graph-based defense schemes effectively bound the
accepted Sybils to the total number of social connections between Sybils and
non-Sybil users. However, Sybils may still evade the defenses by soliciting
many social connections to real users. We propose SybilFence, a system that
improves over social-graph-based Sybil defenses to further thwart Sybils.
SybilFence is based on the observation that even well-maintained fake accounts
inevitably receive a significant number of user negative feedback, such as the
rejections to their friend requests. Our key idea is to discount the social
edges on users that have received negative feedback, thereby limiting the
impact of Sybils' social edges. The preliminary simulation results show that
our proposal is more resilient to attacks where fake accounts continuously
solicit social connections over time.


title: A characteristic property of the space s

abstract:
  It is shown that under certain stability conditions a complemented subspace
of the space $s$ of rapidly decreasing sequences is isomorphic to $s$ and this
condition characterizes $s$. This result is used to show that for the classical
Cantor set $X$ the space $C_\infty(X)$ of restrictions to $X$ of
$C^\infty$-functions on $\R$ is isomorphic to $s$, so completing the theory
developed in "Restriction spaces of $A^\infty$", to appear in Rev. Mat.
Iberoamericana 29.4 (2013)


title: The Geometry of b^k Manifolds

abstract:
  Let $Z$ be a hypersurface of a manifold $M$. The $b$-tangent bundle of $(M,
Z)$, whose sections are vector fields tangent to $Z$, is used to study
pseudodifferential operators and stable Poisson structures on $M$. In this
paper we introduce the $b^k$-tangent bundle, whose sections are vector fields
with "order $k$ tangency" to $Z$. We describe the geometry of this bundle and
its dual, generalize the celebrated Mazzeo-Melrose theorem of the de Rham
theory of $b$-manifolds, and apply these tools to classify certain Poisson
structures on compact oriented surfaces.


title: Torus Invariant Curves

abstract:
  Using the language of T-varieties, we study torus invariant curves on a
complete normal variety $X$ with an effective codimension-one torus action. In
the same way that the $T$-invariant Weil divisors on $X$ are sums of "vertical"
divisors and "horizontal" divisors, so too is each $T$-invariant curve a sum of
"vertical" curves and "horizontal" curves. We give combinatorial formulas that
calculate the intersection between $T$-invariant divisors and $T$-invariant
curves, and generalize the celebrated toric cone theorem to the case of
complete complexity-one $T$-varieties.


title: Cosmology and Time

abstract:
  Time has always played a crucial role in cosmology. I review some of the
aspects of the present cosmological model which are more directly related to
time, such as: the definition of a cosmic time; the existence of typical
timescales and epochs in an expanding universe; the problem of the initial
singularity and the origin of time; the cosmological arrow of time.