title: Repairable Fountain Codes

abstract:
  We introduce a new family of Fountain codes that are systematic and also have
sparse parities. Given an input of $k$ symbols, our codes produce an unbounded
number of output symbols, generating each parity independently by linearly
combining a logarithmic number of randomly selected input symbols. The
construction guarantees that for any $\epsilon>0$ accessing a random subset of
$(1+\epsilon)k$ encoded symbols, asymptotically suffices to recover the $k$
input symbols with high probability.
  Our codes have the additional benefit of logarithmic locality: a single lost
symbol can be repaired by accessing a subset of $O(\log k)$ of the remaining
encoded symbols. This is a desired property for distributed storage systems
where symbols are spread over a network of storage nodes. Beyond recovery upon
loss, local reconstruction provides an efficient alternative for reading
symbols that cannot be accessed directly. In our code, a logarithmic number of
disjoint local groups is associated with each systematic symbol, allowing
multiple parallel reads.
  Our main mathematical contribution involves analyzing the rank of sparse
random matrices with specific structure over finite fields. We rely on
establishing that a new family of sparse random bipartite graphs have perfect
matchings with high probability.


title:
Dynamics of correlations in a quasi-2D dipolar Bose gas following a
  quantum quench

abstract:
  We study the evolution of correlations in a quasi-2D dipolar gas driven
out-of-equilibrium by a sudden ramp of the interaction strength. For
sufficiently strong ramps, the momentum distribution, excited fraction and
density-density correlation function all display pronounced features that are
directly related to the appearance of a roton minimum in the underlying
spectrum. Our study suggests that the evolution of correlations following a
quench can be used as a probe of roton-like excitations in a dipolar gas. We
also find that the build up of density-density correlations following a quench
occurs much more slowly in the dipolar gas compared to a non-dipolar gas, owing
to the long-range interactions.


title: When and how does a prominence-like jet gain kinetic energy?

abstract:
  A jet is a considerable amount of plasma being ejected from the chromosphere
or lower corona into the higher corona and is a common phenomenon. Usually, a
jet is triggered by a brightening or a flare, which provides the first driving
force to push plasma upward. In this process, magnetic reconnection is thought
to be the mechanism to convert magnetic energy into thermal, nonthermal, and
kinetic energies. However, most jets could reach an unusual high altitude and
end much later than the end of its associated flare. This fact implies that
there is another way to continuously transfer magnetic energy into kinetic
energy even after the reconnection. The picture described above is well known
in the community, but how and how much magnetic energy is released through a
way other than reconnection is still unclear. By studying a prominence-like jet
observed by SDO/AIA and STEREO-A/EUVI, we find that the continuous relaxation
of the post-reconnection magnetic field structure is an important process for a
jet to climb up higher than it could through only reconnection. The kinetic
energy of the jet gained through the relaxation is 1.6 times that gained from
the reconnection. The resultant energy flux is hundreds of times larger than
the flux required for the local coronal heating, suggesting that such jets are
a possible source to keep the corona hot. Furthermore, rotational motions
appear all the time during the jet. Our analysis suggests that torsional
Alfv\'en waves induced during reconnection could not be the only mechanism to
release magnetic energy and drive jets.


title:
A physical understanding of how reionization suppresses accretion onto
  dwarf halos

abstract:
  We develop and test with cosmological simulations a physically motivated
theory for how the interplay between gravity, pressure, cooling, and
self-shielding set the redshift--dependent mass scale at which halos can
accrete intergalactic gas. This theory provides a physical explanation for the
halo mass scale that can accrete unshocked intergalactic gas, which has been
explained with ad hoc criteria tuned to reproduce the results of a few
simulations. Furthermore, it provides an intuitive explanation for how this
mass scale depends on the reionization redshift, the amplitude of the ionizing
background, and the redshift. We show that accretion is inhibited onto more
massive halos than had been thought because previous studies had focused on the
gas fraction of halos rather than the instantaneous mass that can accrete gas.
A halo as massive as 10^11 Msun cannot accrete intergalactic gas at z=0, even
though typically its progenitors were able to accrete gas at higher redshifts.
We describe a simple algorithm that can be implemented in semi-analytic models,
and we compare the predictions of this algorithm to numerical simulations.


title:
Spin-symmetric solution of an interacting quantum dot attached to
  superconducting leads: Andreev states and the $0-\pi$ transition

abstract:
  Behavior of Andreev gap states in a quantum dot with Coulomb repulsion
symmetrically attached to superconducting leads is studied via the perturbation
expansion in the interaction strength. We find the exact asymptotic form of the
spin-symmetric solution for the Andreev states continuously approaching the
Fermi level. We thereby derive a critical interaction at which the Andreev
states at zero temperature merge at the Fermi energy, being the upper bound for
the $0-\pi$ transition. We show that the spin-symmetric solution becomes
degenerate beyond this interaction, in the $\pi$ phase, and the Andreev states
do not split unless the degeneracy is lifted. We further demonstrate that the
degeneracy of the spin-symmetric state extends also into the $0$ phase in which
the solutions with zero and non-zero frequencies of the Andreev states may
coexist.


title: Orbifold finiteness under geometric and spectral constraints

abstract:
  The class of Riemannian orbifolds of dimension n defined by a lower bound on
the sectional curvature and the volume and an upper bound on the diameter has
only finitely many members up to orbifold homeomorphism. Furthermore, any class
of isospectral Riemannian orbifolds with a lower bound on the sectional
curvature is finite up to orbifold homeomorphism.


title: Coupling a QFT to a TQFT and Duality

abstract:
  We consider coupling an ordinary quantum field theory with an infinite number
of degrees of freedom to a topological field theory. On R^d the new theory
differs from the original one by the spectrum of operators. Sometimes the local
operators are the same but there are different line operators, surface
operators, etc. The effects of the added topological degrees of freedom are
more dramatic when we compactify R^d, and they are crucial in the context of
electric-magnetic duality. We explore several examples including
Dijkgraaf-Witten theories and their generalizations both in the continuum and
on the lattice. When we couple them to ordinary quantum field theories the
topological degrees of freedom allow us to express certain characteristic
classes of gauge fields as integrals of local densities, thus simplifying the
analysis of their physical consequences.


title: Repulsive gravity near naked singularities and point massive particles

abstract:
  We investigate the existence of repulsive gravitational acceleration near
naked singularities. The investigation is carried out by means of the
acceleration tensor, which is a coordinate invariant object. We find that the
gravitational acceleration is repulsive in the vicinity of the origin in the
Reissner-Nordstr{\o}m and in the Kerr space-times, and attractive at large
distances in the expected Newtonian way. We further address the space-time of a
point massive particle, which also exhibits repulsive effects near the origin.


title: Data Smashing

abstract:
  Investigation of the underlying physics or biology from empirical data
requires a quantifiable notion of similarity - when do two observed data sets
indicate nearly identical generating processes, and when they do not. The
discriminating characteristics to look for in data is often determined by
heuristics designed by experts, $e.g.$, distinct shapes of "folded" lightcurves
may be used as "features" to classify variable stars, while determination of
pathological brain states might require a Fourier analysis of brainwave
activity. Finding good features is non-trivial. Here, we propose a universal
solution to this problem: we delineate a principle for quantifying similarity
between sources of arbitrary data streams, without a priori knowledge, features
or training. We uncover an algebraic structure on a space of symbolic models
for quantized data, and show that such stochastic generators may be added and
uniquely inverted; and that a model and its inverse always sum to the generator
of flat white noise. Therefore, every data stream has an anti-stream: data
generated by the inverse model. Similarity between two streams, then, is the
degree to which one, when summed to the other's anti-stream, mutually
annihilates all statistical structure to noise. We call this data smashing. We
present diverse applications, including disambiguation of brainwaves pertaining
to epileptic seizures, detection of anomalous cardiac rhythms, and
classification of astronomical objects from raw photometry. In our examples,
the data smashing principle, without access to any domain knowledge, meets or
exceeds the performance of specialized algorithms tuned by domain experts.


title: Observations, Modeling and Theory of Debris Disks

abstract:
  Main sequence stars, like the Sun, are often found to be orbited by
circumstellar material that can be categorized into two groups, planets and
debris. The latter is made up of asteroids and comets, as well as the dust and
gas derived from them, which makes debris disks observable in thermal emission
or scattered light. These disks may persist over Gyrs through steady-state
evolution and/or may also experience sporadic stirring and major collisional
breakups, rendering them atypically bright for brief periods of time. Most
interestingly, they provide direct evidence that the physical processes
(whatever they may be) that act to build large oligarchs from micron-sized dust
grains in protoplanetary disks have been successful in a given system, at least
to the extent of building up a significant planetesimal population comparable
to that seen in the Solar System's asteroid and Kuiper belts. Such systems are
prime candidates to host even larger planetary bodies as well. The recent
growth in interest in debris disks has been driven by observational work that
has provided statistics, resolved images, detection of gas in debris disks, and
discoveries of new classes of objects. The interpretation of this vast and
expanding dataset has necessitated significant advances in debris disk theory,
notably in the physics of dust produced in collisional cascades and in the
interaction of debris with planets. Application of this theory has led to the
realization that such observations provide a powerful diagnostic that can be
used not only to refine our understanding of debris disk physics, but also to
challenge our understanding of how planetary systems form and evolve.


title: Ricci Solitons conformally equivalent to left invariant metrics

abstract:
  In this paper, we study the geometry of Riemannian metrics conformally
equivalent to invariant metrics on Lie groups. We give a necessary and
sufficient condition for these metrics to be Ricci solitons. Using the
condition based on structural constants, many explicit examples of shrinking,
steady, and expanding Ricci solitons are given. Finally, we give non-Einstein
examples of Ricci solitons that are not conformally equivalent to
left-invariant Riemannian metrics.


title: Is There a Maximum Star Formation Rate in High-Redshift Galaxies?

abstract:
  We use the James Clerk Maxwell Telescope's SCUBA-2 camera to image a 400
arcmin^2 area surrounding the GOODS-N field. The 850 micron rms noise ranges
from a value of 0.49 mJy in the central region to 3.5 mJy at the outside edge.
From these data, we construct an 850 micron source catalog to 2 mJy containing
49 sources detected above the 4-sigma level. We use an ultradeep (11.5 uJy at
5-sigma) 1.4 GHz image obtained with the Karl G. Jansky Very Large Array
together with observations made with the Submillimeter Array to identify
counterparts to the submillimeter galaxies. For most cases of multiple radio
counterparts, we can identify the correct counterpart from new and existing
Submillimeter Array data. We have spectroscopic redshifts for 62% of the radio
sources in the 9 arcmin radius highest sensitivity region (556/894) and 67% of
the radio sources in the GOODS-N region (367/543). We supplement these with a
modest number of additional photometric redshifts in the GOODS-N region (30).
We measure millimetric redshifts from the radio to submillimeter flux ratios
for the unidentified submillimeter sample, assuming an Arp 220 spectral energy
distribution. We find a radio flux dependent K-z relation for the radio
sources, which we use to estimate redshifts for the remaining radio sources. We
determine the star formation rates (SFRs) of the submillimeter sources based on
their radio powers and their submillimeter and find that they agree well. The
radio data are deep enough to detect star-forming galaxies with SFRs >2000
solar masses per year to z~6. We find galaxies with SFRs up to ~6,000 solar
masses per year over the redshift range z=1.5-6, but we see evidence for a
turn-down in the SFR distribution function above 2000 solar masses per year.


title: Multi-microlocalization and microsupport

abstract:
  The purpose of this paper is to establish the foundations of
multi-microlocalization, in particular, to give the fiber formula for the
multi-microlocalization functor and estimate of microsupport of a
multi-microlocalized object. We also give some applications of these results.


title: Studies of mesic nuclei via decay reactions

abstract:
  Collisions in a system of two particles at energies close to a bound state in
different channels are discussed. Next, the bound state decays into a third
coupled channel. A phenomenological approach to dd->pi-p3He reaction is
presented.


title:
Completely bounded isomorphisms of operator algebras and similarity to
  complete isometries

abstract:
  A well-known theorem of Paulsen says that if $\mathcal{A}$ is a unital
operator algebra and $\phi:\mathcal{A}\to B(\mathcal{H})$ is a unital
completely bounded homomorphism, then $\phi$ is similar to a completely
contractive map $\phi'$. Motivated by classification problems for Hilbert space
contractions, we are interested in making the inverse $\phi'^{-1}$ completely
contractive as well whenever the map $\phi$ has a completely bounded inverse.
We show that there exist invertible operators $X$ and $Y$ such that the map $$
XaX^{-1}\mapsto Y\phi(a)Y^{-1} $$ is completely contractive and is "almost"
isometric on any given finite set of elements from $\mathcal{A}$ with non-zero
spectrum. Although the map cannot be taken to be completely isometric in
general, we show that this can be achieved if $\mathcal{A}$ is completely
boundedly isomorphic to either a $C^*$-algebra or a uniform algebra. In the
case of quotient algebras of $H^\infty$, we translate these conditions in
function theoretic terms and relate them to the classical Carleson condition.


title:
A Comprehensive Review of Heat Transfer in Thermoelectric Materials and
  Devices

abstract:
  Solid-state thermoelectric devices are currently used in applications ranging
from thermocouple sensors to power generators in satellites, to portable
air-conditioners and refrigerators. With the ever-rising demand throughout the
world for energy consumption and CO2 reduction, thermoelectric energy
conversion has been receiving intensified attention as a potential candidate
for waste-heat harvesting as well as for power generation from renewable
sources. Efficient thermoelectric energy conversion critically depends on the
performance of thermoelectric materials and devices. In this review, we discuss
heat transfer in thermoelectric materials and devices, especially phonon
engineering to reduce the lattice thermal conductivity of thermoelectric
materials, which requires a fundamental understanding of nanoscale heat
conduction physics.


title: An Interaction Model for Simulation and Mitigation of Cascading Failures

abstract:
  In this paper the interactions between component failures are quantified and
the interaction matrix and interaction network are obtained. The quantified
interactions can capture the general propagation patterns of the cascades from
utilities or simulation, thus helping to better understand how cascading
failures propagate and to identify key links and key components that are
crucial for cascading failure propagation. By utilizing these interactions a
high-level probabilistic model called interaction model is proposed to study
the influence of interactions on cascading failure risk and to support online
decision-making. It is much more time efficient to first quantify the
interactions between component failures with fewer original cascades from a
more detailed cascading failure model and then perform the interaction model
simulation than it is to directly simulate a large number of cascades with a
more detailed model. Interaction-based mitigation measures are suggested to
mitigate cascading failure risk by weakening key links, which can be achieved
in real systems by wide area protection such as blocking of some specific
protective relays. The proposed interaction quantifying method and interaction
model are validated with line outage data generated by the AC OPA cascading
simulations on the IEEE 118-bus system.


title:
The prompt-early afterglow connection in gamma-ray bursts: implications
  for the early afterglow physics

abstract:
  The early X-ray afterglow of gamma-ray bursts revealed by Swift carried many
surprises. We focus in this paper on the plateau phase whose origin remains
highly debated. We confront several newly discovered correlations between
prompt and afterglow quantities (isotropic emitted energy in gamma-rays,
luminosity and duration of the plateau) to several models proposed for the
origin of plateaus in order to check if they can account for these observed
correlations. We first show that the scenario of plateau formation by energy
injection into the forward shock leads to an efficiency crisis for the prompt
phase and therefore study two possible alternatives: the first one still takes
place within the framework of the standard forward shock model but allows for a
variation of the microphysics parameters to reduce the radiative efficiency at
early times; in the second scenario the early afterglow results from a
long-lived reverse shock. Its shape then depends on the distribution of energy
as a function of Lorentz factor in the ejecta. In both cases, we first present
simple analytical estimates of the plateau luminosity and duration and then
compute detailed light curves. In the two considered scenarios we find that
plateaus following the observed correlations can be obtained under the
condition that specific additional ingredients are included. In the forward
shock scenario, the preferred model supposes a wind external medium and a
microphysics parameter epsilon_e that first varies as n^{-\nu} (n being the
external density), with \nu~1 to get a flat plateau, before staying constant
below a critical density n_0. To produce a plateau in the reverse shock
scenario the ejecta must contain a tail of low Lorentz factor with a peak of
energy deposition at \Gamma >~ 10.


title:
A strong geometric hyperbolicity property for directed graphs and
  monoids

abstract:
  We introduce and study a strong "thin triangle"' condition for directed
graphs, which generalises the usual notion of hyperbolicity for a metric space.
We prove that finitely generated left cancellative monoids whose right Cayley
graphs satisfy this condition must be finitely presented with polynomial Dehn
functions, and hence word problems in NP. Under the additional assumption of
right cancellativity (or in some cases the weaker condition of bounded
indegree), they also admit algorithms for more fundamentally
semigroup-theoretic decision problems such as Green's relations L, R, J, D and
the corresponding pre-orders.
  In contrast, we exhibit a right cancellative (but not left cancellative)
finitely generated monoid (in fact, an infinite class of them) whose Cayley
graph is a essentially a tree (hence hyperbolic in our sense and probably any
reasonable sense), but which is not even recursively presentable. This seems to
be strong evidence that no geometric notion of hyperbolicity will be strong
enough to yield much information about finitely generated monoids in absolute
generality.


title: Clausius' Entropy Revisited

abstract:
  Conventional Non-equilibrium Thermodynamics is mainly concerned with systems
in local equilibrium and their entropy production, due to the irreversible
processes which take place in these systems. In this paper fluids will be
considered in a state of local equilibrium. We argue that the main feature of
such systems is not the entropy production, but the organization of the flowing
currents in such systems. These currents do not only have entropy production,
but must also have an organization needed to flow in a certain direction. It is
the latter, which is the source of the equilibrium entropy, when the fluid goes
from a local equilibrium state and to an equilibrium state. This implies a
transmutation of the local equilibrium current's organization into the
equilibrium entropy. Alternatively, when a fluid goes from an equilibrium state
to a local equilibrium state, its entropy transmutes into the organization of
the currents of that state.


title:
Proof of a conjecture of Kulakova et al. related to the sl_2 weight
  system

abstract:
  In this article, we show that a conjecture raised in [KLMR], which regards
the coefficient of the highest term when we evaluate the sl_2 weight system on
the projection of a diagram to primitive elements, is a consequence of the
Melvin-Morton-Rozansky conjecture, proved in [BNG].


title:
Centers associated with the Borel subalgebra of the general linear Lie
  algebra

abstract:
  We consider a Borel subalgebra $\fg$ of the general linear algebra and its
subalgebra $\BB$ which is a Borel subalgebra of the special linear algebra,
over arbitrary field. Let $\cL\in\{\fg, \BB\}$. We establish here explicit
realizations of the center $Z(\cL)$ and semi-center $Sz(\cL)$ of the enveloping
algebra, the Poisson center $S(\cL)^{\cL}$ and Poisson semi-center
$S(\cL)^{\cL}_{\si}$ of the symmetric algebra. We describe their structure as
commutative rings and establish isomorphisms $Z(\cL)\cong S(\cL)^{\cL}$,
$Sz(\cL)\cong S(\cL)^{\cL}_{\si}$


title:
Algebraic order and the Berezinskii-Kosterlitz-Thouless transition in an
  exciton-polariton gas

abstract:
  We observe quasi-long range coherence in a two-dimensional condensate of
exciton-polaritons. Our measurements are the first to confirm that the spatial
correlation algebraically decays with a slow power-law, whose exponent
quantitatively behaves as predicted by the Berezinskii-Kosterlitz-Thouless
theory. The exciton-polaritons are created by non-resonant optical pumping of a
micro-cavity sample with embedded GaAs quantum-wells at liquid helium
temperature. Michelson interference is used to measure the coherence of the
photons emitted by decaying exciton-polaritons.


title:
Transport of cosmic-ray protons in intermittent heliospheric turbulence:
  model and simulations

abstract:
  The transport of charged energetic particles in the presence of strong
intermittent heliospheric turbulence is computationally analyzed based on known
properties of the interplanetary magnetic field and solar wind plasma at 1
Astronomical Unit (AU). The turbulence is assumed to be static, composite, and
quasi-three-dimensional with a varying energy distribution between a
one-dimensional Alfv\'enic (slab) and a structured two-dimensional component.
The spatial fluctuations of the turbulent magnetic field are modeled either as
homogeneous with a Gaussian probability distribution function (PDF), or as
intermittent on large and small scales with a q-Gaussian PDF. Simulations
showed that energetic particle diffusion coefficients both parallel and
perpendicular to the background magnetic field are significantly affected by
intermittency in the turbulence. This effect is especially strong for parallel
transport where for large-scale intermittency results show an extended phase of
subdiffusive parallel transport during which cross-field transport diffusion
dominates. The effects of intermittency are found to depend on particle
rigidity and the fraction of slab energy in the turbulence, yielding a
perpendicular to parallel mean free path ratio close to 1 for large-scale
intermittency. Investigation of higher order transport moments (kurtosis)
indicates that non-Gaussian statistical properties of the intermittent
turbulent magnetic field are present in the parallel transport, especially for
low rigidity particles at all times.


title: Graph Isomorphism and the Lasserre Hierarchy

abstract:
  In this paper we show lower bounds for a certain large class of algorithms
solving the Graph Isomorphism problem, even on expander graph instances.
Spielman [25] shows an algorithm for isomorphism of strongly regular expander
graphs that runs in time exp(O(n^(1/3)) (this bound was recently improved to
expf O(n^(1/5) [5]). It has since been an open question to remove the
requirement that the graph be strongly regular. Recent algorithmic results show
that for many problems the Lasserre hierarchy works surprisingly well when the
underlying graph has expansion properties. Moreover, recent work of Atserias
and Maneva [3] shows that k rounds of the Lasserre hierarchy is a
generalization of the k-dimensional Weisfeiler-Lehman algorithm for Graph
Isomorphism. These two facts combined make the Lasserre hierarchy a good
candidate for solving graph isomorphism on expander graphs. Our main result
rules out this promising direction by showing that even Omega(n) rounds of the
Lasserre semidefinite program hierarchy fail to solve the Graph Isomorphism
problem even on expander graphs.


title:
Adjusting models of ordered multinomial outcomes for nonignorable
  nonresponse in the occupational employment statistics survey

abstract:
  An establishment's average wage, computed from administrative wage data, has
been found to be related to occupational wages. These occupational wages are a
primary outcome variable for the Bureau of Labor Statistics Occupational
Employment Statistics survey. Motivated by the fact that nonresponse in this
survey is associated with average wage even after accounting for other
establishment characteristics, we propose a method that uses the administrative
data for imputing missing occupational wage values due to nonresponse. This
imputation is complicated by the structure of the data. Since occupational wage
data is collected in the form of counts of employees in predefined wage ranges
for each occupation, weighting approaches to deal with nonresponse do not
adequately adjust the estimates for certain domains of estimation. To preserve
the current data structure, we propose a method to impute each missing
establishment's wage interval count data as an ordered multinomial random
variable using a separate survival model for each occupation. Each model
incorporates known auxiliary information for each establishment associated with
the distribution of the occupational wage data, including geographic and
industry characteristics. This flexible model allows the baseline hazard to
vary by occupation while allowing predictors to adjust the probabilities of an
employee's salary falling within the specified ranges. An empirical study and
simulation results suggest that the method imputes missing OES wages that are
associated with the average wage of the establishment in a way that more
closely resembles the observed association.


title:
Multiscale modelling of polymer structure and conformations in polymer
  nanocomposites: A Review

abstract:
  Over the past two decades polymer nanocomposites have received tremendous
interest from industry and academia due to their advanced properties
comparative to polymer blends. Many computational studies have revealed that
the macroscopic properties of polymer nanocomposites depend strongly on the
microscopic polymer structure and conformations. In this article we review
simulation studies of the fundamental problem of polymer structure and
dimensions in nanocomposites containing bare spherical or rod nanoparticles.
Experimentally, there is controversy over whether the addition of nanoparticles
in a polymer matrix can perturb the polymer chains.


title:
Chemical and photometric evolution models for disk, irregular and low
  mass galaxies

abstract:
  We summarize the updated set of multiphase chemical evolution models
performed with 44 theoretical radial mass initial distributions and 10 possible
values of efficiencies to form molecular clouds and stars. We present the
results about the infall rate histories, the formation of the disk, and the
evolution of the radial distributions of diffuse and molecular gas surface
density, stellar profile, star formation rate surface density and elemental
abundances of C,N, O and Fe, finding that the radial gradients for these
elements begin very steeper, and flatten with increasing time or decreasing
redshift, although the outer disks always show a certain flattening for all
times. With the resulting star formation and enrichment histories, we calculate
the spectral energy distributions (SEDs) for each radial region by using the
ones for single stellar populations resulting from the evolutive synthesis
model {\sc popstar}. With these SEDs we may compute finally the broad band
magnitudes and colors radial distributions in the Johnson and in the SLOAN/SDSS
systems which are the main result of this work. We present the evolution of
these brightness and color profiles with the redshift.


title: Bifurcation values of polynomial functions and perverse sheaves

abstract:
  We characterize bifurcation values of polynomial functions by using the
theory of perverse sheaves and their vanishing cycles. In particular, by
introducing a method to compute the jumps of the Euler characteristics with
compact support of their fibers, we confirm the conjecture of N\'emethi-Zaharia
in many cases.


title:
A Study of Successive Over-relaxation Method Parallelization Over Modern
  HPC Languages

abstract:
  Successive over-relaxation (SOR) is a computationally intensive, yet
extremely important iterative solver for solving linear systems. Due to recent
trends of exponential growth in amount of data generated and increasing problem
sizes, serial platforms have proved to be insufficient in providing the
required computational power. In this paper, we present parallel
implementations of red-black SOR method using three modern programming
languages namely Chapel, D and Go. We employ SOR method for solving 2D
steady-state heat conduction problem. We discuss the optimizations incorporated
and the features of these languages which are crucial for improving the program
performance. Experiments have been performed using 2, 4, and 8 threads and
performance results are compared with serial execution. The analysis of results
provides important insights into working of SOR method.


title: Context-Aware Hypergraph Construction for Robust Spectral Clustering

abstract:
  Spectral clustering is a powerful tool for unsupervised data analysis. In
this paper, we propose a context-aware hypergraph similarity measure (CAHSM),
which leads to robust spectral clustering in the case of noisy data. We
construct three types of hypergraph---the pairwise hypergraph, the
k-nearest-neighbor (kNN) hypergraph, and the high-order over-clustering
hypergraph. The pairwise hypergraph captures the pairwise similarity of data
points; the kNN hypergraph captures the neighborhood of each point; and the
clustering hypergraph encodes high-order contexts within the dataset. By
combining the affinity information from these three hypergraphs, the CAHSM
algorithm is able to explore the intrinsic topological information of the
dataset. Therefore, data clustering using CAHSM tends to be more robust.
Considering the intra-cluster compactness and the inter-cluster separability of
vertices, we further design a discriminative hypergraph partitioning criterion
(DHPC). Using both CAHSM and DHPC, a robust spectral clustering algorithm is
developed. Theoretical analysis and experimental evaluation demonstrate the
effectiveness and robustness of the proposed algorithm.


title:
A Survey of Techniques For Improving Energy Efficiency in Embedded
  Computing Systems

abstract:
  Recent technological advances have greatly improved the performance and
features of embedded systems. With the number of just mobile devices now
reaching nearly equal to the population of earth, embedded systems have truly
become ubiquitous. These trends, however, have also made the task of managing
their power consumption extremely challenging. In recent years, several
techniques have been proposed to address this issue. In this paper, we survey
the techniques for managing power consumption of embedded systems. We discuss
the need of power management and provide a classification of the techniques on
several important parameters to highlight their similarities and differences.
This paper is intended to help the researchers and application-developers in
gaining insights into the working of power management techniques and designing
even more efficient high-performance embedded systems of tomorrow.


title: Using CMOS Sensors in a Cellphone for Gamma Detection and Classification

abstract:
  The CMOS camera found in many cellphones is sensitive to ionized electrons.
Gamma rays penetrate into the phone and produce ionized electrons that are then
detected by the camera. Thermal noise and other noise needs to be removed on
the phone, which requires an algorithm that has relatively low memory and
computational requirements. The continuous high-delta algorithm described fits
those requirements. Only a small fraction of the energy of even the electron is
deposited in the camera sensor, so direct methods of measuring the energy
cannot be used. The fraction of groups of lit up pixels that are lines is
correlated with the energy of the gamma rays. This correlation under certain
conditions allows limited low resolution energy resolution to be performed.


title: From Kernel Machines to Ensemble Learning

abstract:
  Ensemble methods such as boosting combine multiple learners to obtain better
prediction than could be obtained from any individual learner. Here we propose
a principled framework for directly constructing ensemble learning methods from
kernel methods. Unlike previous studies showing the equivalence between
boosting and support vector machines (SVMs), which needs a translation
procedure, we show that it is possible to design boosting-like procedure to
solve the SVM optimization problems.
  In other words, it is possible to design ensemble methods directly from SVM
without any middle procedure.
  This finding not only enables us to design new ensemble learning methods
directly from kernel methods, but also makes it possible to take advantage of
those highly-optimized fast linear SVM solvers for ensemble learning.
  We exemplify this framework for designing binary ensemble learning as well as
a new multi-class ensemble learning methods.
  Experimental results demonstrate the flexibility and usefulness of the
proposed framework.


title:
The evolution-dominated hydrodynamic model and the pseudorapidity
  distributions in high energy physics

abstract:
  By taking into account the effects of leading particles, we discuss the
pseudorapidity distributions of the charged particles produced in high energy
heavy ion collisions in the context of evolution-dominated hydrodynamic model.
The leading particles are supposed to have a Gaussian rapidity distribution
normalized to the number of participants. A comparison is made between the
theoretical results and the experimental measurements performed by BRAHMS and
PHOBOS Collaboration at BNL-RHIC in Au-Au and Cu-Cu collisions at sqrt(s_NN)
=200 GeV and by ALICE Collaboration at CERN-LHC in Pb-Pb collisions at
sqrt(s_NN) =2.76 TeV.


title:
Complete asymptotic expansion of the spectral function of
  multidimensional almost-periodic Schrodinger operators

abstract:
  We prove the complete asymptotic expansion of the spectral function (the
integral kernel of the spectral projection) of a Schrodinger operator
$H=-\Delta+b$ acting in $R^d$ when the potential $b$ is real and either smooth
periodic, or generic quasi-periodic (finite linear combination of
exponentials), or belongs to a wide class of almost-periodic functions.


title: The Expected Shape of Random Doubly Alternating Baxter Permutations

abstract:
  Guibert and Linusson introduced the family of doubly alternating Baxter
permutations, i.e. Baxter permutations $\sigma \in S_n$, such that $\sigma$ and
$\sigma^{-1}$ are alternating. They proved that the number of such permutations
in $S_{2n}$ and $S_{2n+1}$ is the Catalan number $C_n$. In this paper we
explore the expected limit shape of such permutations, following the approach
by Miner and Pak.


title:
Entropy production and fluctuation theorems for Langevin processes under
  continuous non-Markovian feedback control

abstract:
  Continuous feedback control of Langevin processes may be non-Markovian due to
a time lag between the measurement and the control action. We show that this
requires to modify the basic relation between dissipation and time-reversal and
to include a contribution arising from the non-causal character of the reverse
process. We then propose a new definition of the quantity measuring the
irreversibility of a path in a nonequilibrium stationary state, which can be
also regarded as the trajectory-dependent total entropy production. This leads
to an extension of the second law which takes a simple form in the long-time
limit. As an illustration, we apply the general approach to linear systems
which are both analytically tractable and experimentally relevant.


title: Rotational Behaviors and Magnetic Field Evolution of Radio Pulsars

abstract:
  The observed long-term spin-down evolution of isolated radio pulsars cannot
be explained by the standard magnetic dipole radiation with a constant braking
torque. However how and why the torque varies still remains controversial,
which is an outstanding problem in our understanding of neutron stars. We have
constructed a phenomenological model of the evolution of surface magnetic
fields of pulsars, which contains a long-term decay modulated by short-term
oscillations; a pulsar's spin is thus modified by its magnetic field evolution.
The predictions of this model agree with the precisely measured spin evolutions
of several individual pulsars; the derived parameters suggest that the Hall
drift and Hall waves in the NS crusts are probably responsible for the
long-term change and short-term quasi-periodical oscillations, respectively.
Many statistical properties of the timing noise of pulsars can be well
re-produced with this model, including correlations and the distributions of
the observed braking indices of the pulsars, which span over a range of more
than 100 millions. We have also presented a phenomenological model for the
recovery processes of classical and slow glitches, which can successfully model
the observed slow and classical glitch events without biases.


title: The Ultraviolet Attenuation Law in Backlit Spiral Galaxies

abstract:
  (Abridged) The effective extinction law (attenuation behavior) in galaxies in
the emitted ultraviolet is well known only for actively star-forming objects
and combines effects of the grain properties, fine structure in the dust
distribution, and relative distributions of stars and dust. We use GALEX, XMM
Optical Monitor, and HST data to explore the UV attenuation in the outer parts
of spiral disks which are backlit by other UV-bright galaxies, starting with
candidates provided by Galaxy Zoo participants. Our analysis incorporates
galaxy symmetry, using non-overlapping regions of each galaxy to derive error
estimates on the attenuation measurements. The entire sample has an attenuation
law close to the Calzetti et al. (1994) form; the UV slope for the overall
sample is substantially shallower than found by Wild et al. (2011), a
reasonable match to the more distant galaxies in our sample but not to the
weighted combination including NGC 2207. The nearby, bright spiral NGC 2207
alone gives accuracy almost equal to the rest of our sample, and its outer arms
have a very low level of foreground starlight. This "grey" law can be produced
from the distribution of dust alone, without a necessary contribution from
differential escape of stars from dense clouds. The extrapolation needed to
compare attenution between backlit galaxies at moderate redshifts, and local
systems from SDSS data, is mild enough to allow use of galaxy overlaps to trace
the cosmic history of dust. For NGC 2207, the covering factor of clouds with
small optical attenuation becomes a dominant factor farther into the
ultraviolet, which opens the possibility that widespread diffuse dust dominates
over dust in star-forming regions deep into the ultraviolet. Comparison with
published radiative-transfer models indicates that the role of dust clumping
dominates over differences in grain populations, at this spatial resolution.


title: Quantum Limit on Stability of Clocks in a Gravitational Field

abstract:
  Good clocks are of importance both to fundamental physics and for
applications in astronomy, metrology and global positioning systems. In a
recent technological breakthrough, researchers at NIST have been able to
achieve a stability of 1 part in $10^{18}$ using an Ytterbium clock. This
naturally raises the question of whether there are fundamental limits to the
stability of clocks. In this paper we point out that gravity and quantum
mechanics set a fundamental limit on the stability of clocks. This limit comes
from a combination of the uncertainty relation, the gravitational redshift and
the relativistic time dilation effect. For example, a single ion hydrogen maser
clock in a terrestrial gravitational field cannot achieve a stability better
than one part in $10^{22}$. This observation has implications for laboratory
experiments involving both gravity and quantum theory.


title: The index formula for the Hecke group H_5

abstract:
  The present article gives the index formula of the principal congruence
subgroups of the Hecke group H_5


title: Wohlfahrt's Theorem for the Hecke group G_5

abstract:
  Let K be a subgroup of the inhomogeneous Hecke group G_5 of finite index.
Suppose that the geometric level of K is r. Then K is congruence if and only if
K contains the principal congruence subgroup of level 2r.


title:
Symplectic topology of Lagrangian submanifolds of CP^n with intermediate
  minimal Maslov numbers

abstract:
  We examine symplectic topological features of certain family of monotone
Lagrangian submanifolds in CP^n. Firstly, we give a cohomological restriction
for Lagrangian submanifolds in CP^n whose first integral homologies are
3-torsion. In particular, in the case where n=5,8, we prove the cohomologies
with coefficients in Z_2 of such Lagrangian submanifolds are isomorphic to that
of SU(3)/(SO(3) Z_3) and SU(3)/Z_3, respectively. Secondly, we calculate the
Floer cohomology of a monotone Lagrangian submanifold SU(p)/Z_p in CP^{p^2-1}
with coefficients in Z_2 by using Biran-Cornea's theory.


title:
Modeling and Predicting Popularity Dynamics via Reinforced Poisson
  Processes

abstract:
  An ability to predict the popularity dynamics of individual items within a
complex evolving system has important implications in an array of areas. Here
we propose a generative probabilistic framework using a reinforced Poisson
process to model explicitly the process through which individual items gain
their popularity. This model distinguishes itself from existing models via its
capability of modeling the arrival process of popularity and its remarkable
power at predicting the popularity of individual items. It possesses the
flexibility of applying Bayesian treatment to further improve the predictive
power using a conjugate prior. Extensive experiments on a longitudinal citation
dataset demonstrate that this model consistently outperforms existing
popularity prediction methods.


title:
Linearization of two dimensional complex-linearizable system of second
  order ordinary differential equations

abstract:
  Complex-linearization of a class of systems of second order ordinary
differential equations (ODEs) has already been studied with complex symmetry
analysis. Linearization of this class has been achieved earlier by complex
method, however, linearization criteria and the most general linearizable form
of such systems have not been derived yet. In this paper, it is shown that the
general linearizable form of the complex-linearizable systems of two second
order ODEs is (at most) quadratically semi-linear in the first order
derivatives of the dependent variables. Further, linearization conditions are
derived in terms of coefficients of system and their derivatives. These
linearizable 2-dimensional complex-linearizable systems of second order ODEs
are characterized here, by adopting both the real and complex procedures.


title: From random matrices to long range dependence

abstract:
  Random matrices whose entries come from a stationary Gaussian process are
studied. The limiting behavior of the eigenvalues as the size of the matrix
goes to infinity is the main subject of interest in this work. It is shown that
the limiting spectral distribution is determined by the absolutely continuous
component of the spectral measure of the stationary process, a phenomenon
resembling that in the situation where the entries of the matrix are i.i.d. On
the other hand, the discrete component contributes to the limiting behavior of
the eigenvalues in a completely different way. Therefore, this helps to define
a boundary between short and long range dependence of a stationary Gaussian
process in the context of random matrices.


title:
Ensuring Predictable Contact Opportunity for Scalable Vehicular Internet
  Access On the Go

abstract:
  With increasing popularity of media enabled hand-helds and their integration
with the in-vehicle entertainment systems, the need for high data-rate services
for mobile users on the go is evident. This ever-increasing demand of data is
constantly surpassing what cellular networks can economically support.
Large-scale Wireless LANs (WLANs) can provide such a service, but they are
expensive to deploy and maintain. Open WLAN access-points, on the other hand,
need no new deployments, but can offer only opportunistic services, lacking any
performance guarantees. In contrast, a carefully planned sparse deployment of
roadside WiFi provides an economically scalable infrastructure with quality of
service assurance to mobile users. In this paper, we present a new metric,
called Contact Opportunity, to closely model the quality of data service that a
mobile user might experience when driving through the system. We then present
efficient deployment algorithms for minimizing the cost for ensuring a required
level of contact opportunity. We further extend this concept and the deployment
techniques to a more intuitive metric -- the average throughput -- by taking
various dynamic elements into account. Simulations over a real road network and
experimental results show that our approach achieves significantly better cost
vs. throughput tradeoff in both the worst case and average case compared with
some commonly used deployment algorithms.


title:
A real-space method for highly parallelizable electronic transport
  calculations

abstract:
  We present a real-space method for first-principles nano-scale electronic
transport calculations. We use the non-equilibrium Green's function method with
density functional theory and implement absorbing boundary conditions (ABCs,
also known as complex absorbing potentials, or CAPs) to represent the effects
of the semi-infinite leads. In real space, the Kohn-Sham Hamiltonian matrix is
highly sparse. As a result, the transport problem parallelizes naturally and
can scale favorably with system size, enabling the computation of conductance
in relatively large molecular junction models. Our use of ABCs circumvents the
demanding task of explicitly calculating the leads' self-energies from surface
Green's functions, and is expected to be more accurate than the use of the
jellium approximation. In addition, we take advantage of the sparsity in real
space to solve efficiently for the Green's function over the entire energy
range relevant to low-bias transport. We illustrate the advantages of our
method with calculations on several challenging test systems and find good
agreement with reference calculation results.


title: The Canonical Structure of the Superstring Action

abstract:
  We consider the canonical structure of the Green-Schwarz superstring in $9 +
1$ dimensions using the Dirac constraint formalism; it is shown that its
structure is similar to that of the superparticle in $2 + 1$ and $3 + 1$
dimensions. A key feature of this structure is that the primary Fermionic
constraints can be divided into two groups using field-independent projection
operators; if one of these groups is eliminated through use of a Dirac Bracket
(DB) then the second group of primary Fermionic constraints becomes first
class. (This is what also happens with the superparticle action.) These primary
Fermionic first class constraints can be used to find the generator of a local
Fermionic gauge symmetry of the action. We also consider the superstring action
in other dimensions of space-time to see if the Fermionic gauge symmetry can be
made simpler than it is in $2 + 1$, $3 + 1$ and $9 + 1$ dimensions. With a $3 +
3$ dimensional target space, we find that such a simplification occurs. We
finally show how in five dimensions there is no first class Fermionic
constraint.


title:
How does Casimir energy fall? IV. Gravitational interaction of
  regularized quantum vacuum energy

abstract:
  Several years ago we demonstrated that the Casimir energy for perfectly
reflecting and imperfectly reflecting parallel plates gravitated normally, that
is, obeyed the equivalence principle. At that time the divergences in the
theory were treated only formally, without proper regularization, and the
coupling to gravity was limited to the canonical energy-momentum-stress tensor.
Here we strengthen the result by removing both of those limitations. We
consider, as a toy model, massless scalar fields interacting with
semitransparent ($\delta$-function) potentials defining parallel plates, which
become Dirichlet plates for strong coupling. We insert space and time
point-split regulation parameters, and obtain well-defined contributions to the
self- energy of each plate, and the interaction energy between the plates.
(This self-energy does not vanish even in the conformally-coupled,
strong-coupled limit.) We also compute the local energy density, which requires
regularization near the plates. In general, the energy density includes a
surface energy that resides precisely on the boundaries. This energy is also
regulated. The gravitational interaction of this well-defined system is then
investigated, and it is verified that the equivalence principle is satisfied.


title:
P-V Criticality of Topological Black Holes in Lovelock-Born-Infeld
  Gravity

abstract:
  To understand the effect of third order Lovelock gravity, $P-V$ criticality
of topological AdS black holes in Lovelock-Born-Infeld gravity is investigated.
The thermodynamics is further explored with some more extensions and details
than the former literature. A detailed analysis of the limit case
$\beta\rightarrow\infty$ is performed for the seven-dimensional black holes. It
is shown that for the spherical topology, $P-V$ criticality exists for both the
uncharged and charged cases. Our results demonstrate again that the charge is
not the indispensable condition of $P-V$ criticality. It may be attributed to
the effect of higher derivative terms of curvature because similar phenomenon
was also found for Gauss-Bonnet black holes. For $k=0$, there would be no $P-V$
criticality. Interesting findings occur in the case $k=-1$, in which positive
solutions of critical points are found for both the uncharged and charged
cases. However, the $P-v$ diagram is quite strange. To check whether these
findings are physical, we give the analysis on the non-negative definiteness
condition of entropy. It is shown that for any nontrivial value of $\alpha$,
the entropy is always positive for any specific volume $v$. Since no $P-V$
criticality exists for $k=-1$ in Einstein gravity and Gauss-Bonnet gravity, we
can relate our findings with the peculiar property of third order Lovelock
gravity. The entropy in third order Lovelock gravity consists of extra terms
which is absent in the Gauss-Bonnet black holes, which makes the critical
points satisfy the constraint of non-negative definiteness condition of
entropy. We also check the Gibbs free energy graph and the "swallow tail"
behavior can be observed. Moreover, the effect of nonlinear electrodynamics is
also included in our research.


title: Optical Solitons in a Trinal-channel Inverted Nonlinear Photonic Crystal

abstract:
  Inverted nonlinear photonic crystals are the crystals featuring competition
between linear and nonlinear lattices, with minima of the linear potential
coinciding with maxima of the nonlinear pseudopotential, and vice versa.
Traditional inverted nonlinear photonic crystals only have two channels, and
can be attained experimentally by means of Rhodamine B (RhB, a dye featuring
saturable absorption) doped into the SU-8 polymer. In this paper, a new type of
inverted nonlinear photonic crystal is constructed by juxtaposing three kinds
of channels into a period. These three channels are a purely linear channel, a
saturable self-focusing nonlinear channel, and a saturable self-defocusing
nonlinear channel. This optical device is assumed to be fabricated by means of
SU-8 polymer material periodically doped with two types of active dyes. The
nonlinear propagation of a light field inside this device (passing along the
channel) can be described by a nonlinear Schrodinger equation. Stable
multi-peak fundamental and dipole solitons are found in the first gap of the
system. These solitons sufficiently exhibit some interesting digital
properties, which may have potential in optical communications.


title: Regular and conformal regular cores for static and rotating solutions

abstract:
  Using a new metric for generating rotating solutions, we derive in a general
fashion the solution of an imperfect fluid and that of its conformal homolog.
We discuss the conditions that the stress-energy tensors and invariant scalars
be regular. On classical physical grounds, it is stressed that, conformal
fluids used as cores for static or rotating solutions, are exempt from any
malicious behavior in that they are finite and defined everywhere.


title: Finite-size scaling at quantum transitions

abstract:
  We develop the finite-size scaling (FSS) theory at quantum transitions,
considering generic boundary conditions, such as open and periodic boundary
conditions, and also the corrections to the leading FSS behaviors. Using
renormalization-group (RG) theory, we generalize Wegner's scaling Ansatz to the
quantum case, classifying the different sources of scaling corrections. We
identify nonanalytic corrections due to irrelevant (bulk and boundary) RG
perturbations and analytic contributions due to regular backgrounds and
analytic expansions of the nonlinear scaling fields.
  To check the general predictions, we consider the quantum XY chain in a
transverse field. For this model exact or numerically accurate results can be
obtained by exploiting its fermionic quadratic representation. We study the FSS
of several observables, such as the free energy, the energy differences between
low-energy levels, correlation functions of the order parameter, etc.,
confirming the general predictions in all cases. Moreover, we consider
bipartite entanglement entropies, which are characterized by the presence of
additional scaling corrections, as predicted by conformal field theory.


title:
Classification of 2-dimensional graded normal hypersurfaces with
  $a(R)\le 6$

abstract:
  Let k be a field of any characteristic and R = k[x,y,z]/(f) be a graded
normal hypersurface. We call (a,b,c; h) = deg(x,y,z;f) the type of R with
gcd(a,b,c)=1. Then the a-invariant a(R) is given by h - (a+b+c). The
classification of such R (or f) was made by many authors (Arnold, Saito,
Wagreich, ...). Here we classify the possible types of R for a fixed a(R) with
$- 1 \le a(R) \le 6$ by commutative ring theoretic method using the
Dolgachev-Pinkham-Demazure construction of normal graded rings. We also show
that if we fix $a(R) \ge 0$, then the number of possible types of R is finite.


title: A Formulation of the Ring Polymer Molecular Dynamics

abstract:
  The exact formulation of the path integral centroid dynamics is extended to
include composites of the position and momentum operators. We present the
generalized centroid dynamics (GCD), which provides a basis to calculate
Kubo-transformed correlation functions by means of classical averages. We
define various types of approximate GCD, one of which is equivalent to the ring
polymer molecular dynamics (RPMD). The RPMD and another approximate GCD are
tested in one-dimensional harmonic system, and it is shown that the RPMD works
better in the short time region.


title: The Brauer group and indecomposable (2,1)-cycles

abstract:
  We show that the torsion in the group of indecomposable $(2,1)$-cycles on a
smooth projective variety over an algebraically closed field is isomorphic to a
twist of its Brauer group, away from the characteristic. In particular, this
group is infinite as soon as $b_2-\rho>0$. We derive a new insight into
Roitman's theorem on torsion $0$-cycles over a surface.


title:
Doping evolution of the superconducting gap structure in heavily
  hole-doped Ba$_{1-x}$K$_x$Fe$_2$As$_2$: heat transport study

abstract:
  We performed systematic thermal conductivity measurements on heavily
hole-doped Ba$_{1-x}$K$_x$Fe$_2$As$_2$ single crystals with 0.747 $\leq x \leq$
0.974. At $x$ = 0.747, the $\kappa_0/T$ is negligible, indicating nodeless
superconducting gap. A small residual linear term $\kappa_0/T$ ($\approx$ 0.035
mW/K$^2$ cm) appears at $x$ = 0.826, and it increases slowly up to $x$ = 0.974,
followed by a drastic increase of more than 20 times to the pure KFe$_2$As$_2$
($x$ = 1.0). This doping dependence of $\kappa_0/T$ clearly shows that the
nodal gap appears near $x = 0.8$, likely associated with the change of Fermi
surface topology. The small values of $\kappa_0/T$ from $x$ = 0.826 to 0.974
support a "$\curlyvee$"-shaped nodal $s$-wave gap recently revealed by
angle-resolved photoemission spectroscopy experiments at $x$ = 0.9.
Furthermore, the drastic increase of $\kappa_0/T$ from $x$ = 0.974 to 1.0 is
inconsistent with a symmetry-imposed $d$-wave gap in KFe$_2$As$_2$, and the
possible nodal gap structure in KFe$_2$As$_2$ is discussed.


title: The discriminant controls automorphism groups of noncommutative algebras

abstract:
  We use the discriminant to determine the automorphism groups of some
noncommutative algebras, and we prove that a family of noncommutative algebras
has tractable automorphism groups.


title: Properties of phoneme N -grams across the world's language families

abstract:
  In this article, we investigate the properties of phoneme N-grams across half
of the world's languages. We investigate if the sizes of three different N-gram
distributions of the world's language families obey a power law. Further, the
N-gram distributions of language families parallel the sizes of the families,
which seem to obey a power law distribution. The correlation between N-gram
distributions and language family sizes improves with increasing values of N.
We applied statistical tests, originally given by physicists, to test the
hypothesis of power law fit to twelve different datasets. The study also raises
some new questions about the use of N-gram distributions in linguistic
research, which we answer by running a statistical test.


title:
On Application of the Lyapunov-Schmidt-Trenogin Method to Bifurcation
  Analysis of the Vlasov-Maxwell system

abstract:
  The review of existence theorems of bifurcation points of solutions for
nonlinear operator equation in Banach spaces is presented.
  The sufficient conditions of bifurcation of solutions of boundary-value
problem for Vlasov-Maxwell system are considered. The analytical method of
Lyapunov-Schmidt-Trenogin is employed.


title:
Entanglement and quantum teleportation via decohered tripartite
  entangled states

abstract:
  The entanglement behavior of two classes of multi-qubit system, GHZ and GHZ
like states passing through a generalized amplitude damping channel is
discussed. Despite this channel causes degradation of the entangled properties
and consequently their abilities to perform quantum teleportation, one can
always improve the lower values of the entanglement and the fidelity of the
teleportrd state by controlling on Bell measurements, analyzer angle and
channel's strength. Using GHZ-like state within a generalized amplitude damping
channel is much better than using the normal GHZ-state, where the decay rate of
entanglement and the fidelity of the teleported states are smaller than those
depicted for GHZ state.


title:
Interpolation of analytic functions of moderate growth in the unit disc
  and zeros of solutions of a linear differential equation

abstract:
  In 2002 A.\ Hartmann and X.\ Massaneda obtained necessary and sufficient
conditions for interpolation sequences for classes of analytic functions in the
unit disc such that $\log M(r,f)=O((1-r)^{-\rho})$, $0<r<1$, $\rho \in (0 ,
+\infty)$, where $M(r,f)=\max\{ |f(z)|: |z|=r\}$. Using another method, we give
an explicit construction of an interpolating function in this result. As an
application we describe minimal growth of the coefficient $a$ such that the
equation $f''+a(z)f=0$ possesses a solution with a prescribed sequence of
zeros.


title:
Domain decomposition methods with overlapping subdomains for
  time-dependent problems

abstract:
  Domain decomposition (DD) methods for solving time-dependent problems can be
classified by (i) the method of domain decomposition used, (ii) the choice of
decomposition operators (exchange of boundary conditions), and (iii) the
splitting scheme employed. To construct homogeneous numerical algorithms,
overlapping subdomain methods are preferable. Domain decomposition is
associated with the corresponding additive representation of the problem
operator. To solve time-dependent problems with the DD splitting, different
operator-splitting schemes are used. Various variants of decomposition
operators differ by distinct types of data exchanges on interfaces. They ensure
the convergence of the approximate solution in various spaces of grid
functions.


title: User Equilibrium Route Assignment for Microscopic Pedestrian Simulation

abstract:
  For the simulation of pedestrians a method is introduced to find routing
alternatives from any origin position to a given destination area in a given
geometry composed of walking areas and obstacles. The method includes a
parameter which sets a threshold for the approximate minimum size of obstacles
to generate routing alternatives. The resulting data structure for navigation
is constructed such that it does not introduce artifacts to the movement of
simulated pedestrians and that locally pedestrians prefer to walk on the
shortest path. The generated set of routes can be used with iterating static or
dynamic assignment methods.

categories: physics.soc-ph cs.CE cs.MA cs.RO physics.comp-ph


title: Les Interactions Fondamentales et la Structure de l'Espace-temps

abstract:
  In the light of intriguing results of C.C.Barros, we investigate in this
thesis the possibilities of geometrical interpretation of all the fundamental
interactions in order to unify them. More exactly we try to supply a unified
geometrical description for gravitation and electromagnetism.
  The analysis of Huei's standard approach of Linear Gravity, in which the
Einstein equations can be written in the same form of the Maxwell ones,
revealed the existence of some imperfections. In fact, the relation between the
scalar potential and the electric-type field is not valid except in the
harmonic gauge, the Lorentz-type force is obtained with a time independence
restriction and an undesired factor 4 appears in the magnetic-type part. A
subtle gauge conditions allows us to eliminate these imperfections and to
revisit the Linear Gravity in a way to get a strong similarity with
electromagnetism. In the linear case, we showed that Maxwell's equations could
be derived from an electromagnetic version of the Einstein ones, and that the
higher order terms are negligible in the current domain of application of
electromagnetism.


title:
Periodic ordering of clusters and stripes in a two-dimensional lattice
  model. I. Ground state, mean-field phase diagram and structure of the
  disordered phases

abstract:
  The short-range attraction and long-range repulsion (SALR) between
nanoparticles or macromolecules can lead to spontaneous pattern formation on
solid surfaces, fluid interfaces or membranes. In order to study the
self-assembly in such systems we consider a triangular lattice model with
nearest-neighbour attraction and third-neighbour repulsion. At the ground state
of the model ($T=0$) the lattice is empty for small values of the chemical
potential $\mu$, and fully occupied for large $\mu$. For intermediate values of
$\mu$ periodically distributed clusters, bubbles or stripes appear if the
repulsion is sufficiently strong. At the phase coexistences between the vacuum
and the ordered cluster phases and between the cluster and the lamellar
(stripe) phases the entropy per site does not vanish. As a consequence of this
ground state degeneracy, disordered fluid phases consisting of clusters or
stripes are stable, and the surface tension vanishes. For $T>0$ we construct
the phase diagram in the mean-field approximation and calculate the correlation
function in the self-consistent Brazovskii-type field theory.


title: A stochastic model for Case-Based Reasoning

abstract:
  Case-Bsed Reasoning (CBR) is a recent theory for problem-solving and learning
in computers and people.Broadly construed it is the process of solving new
problems based on the solution of similar past problems. In the present paper
we introduce an absorbing Markov chain on the main steps of the CBR process.In
this way we succeed in obtaining the probabilities for the above process to be
in a certain step at a certain phase of the solution of the corresponding
problem, and a measure for the efficiency of a CBR system. Examples are given
to illustrate our results.


title: Structure functions and minimal path sets

abstract:
  In this short note we give and discuss a general multilinear expression of
the structure function of an arbitrary semicoherent system in terms of its
minimal path and cut sets. We also examine the link between the number of
minimal path and cut sets consisting of 1 or 2 components and the concept of
structure signature of the system.


title:
The ultra-low-frequency shear modes of 2-4 layer graphenes observed in
  their scroll structures at edges

abstract:
  The in-plane shear modes between neighbor-layers of 2-4 layer graphenes (LGs)
and the corresponding graphene scrolls rolled up by 2-4LGs were investigated by
Raman scattering. In contrast to that just one shear mode was observed in
3-4LGs, all the shear modes of 3-4LGs were observed in 3-4 layer scrolls (LSs),
whose frequencies agree well with the theoretical predication by both a
force-constant model and a linear chain model. In comparison to the broad width
(about 12cm$^{-1}$) for the G band in graphite, all the shear modes exhibit an
intrinsic line width of about 1.0 cm$^{-1}$. The local electronic structures
dependent on the local staking configurations enhance the intensity of the
shear modes in corresponding 2-4LSs zones, which makes it possible to observe
all the shear modes. It provides a direct evidence that how the band structures
of FLGs can be sensitive to local staking configurations. This result can be
extended to n layer graphene (n > 4) for the understanding of the basic phonon
properties of multi-layer graphenes. This observation of all-scale shear modes
can be foreseen in other 2D materials with similar scroll structures.


title: Warm dense matter conductivity including electron-electron collisions

abstract:
  The controversy with respect to the role of electron-electron collisions in
the dynamic conductivity of dense plasmas is resolved. In particular, the dc
conductivity is analyzed in the low-density, non-degenerate limit where the
Spitzer theory is valid and electron-electron collisions lead to the well-known
reduction of the result for a Lorentz plasma. With increasing degeneracy, the
contribution of electron-electron collisions to the dc conductivity is
decreasing and can be neglected for the liquid metal domain where the
Ziman-Faber theory is applicable. We show how electron-electron collisions have
to be implemented in calculations based on the Kubo-Greenwood formula which is
prevalently applied in simulations for the frequency-dependent conductivity in
the warm dense matter region, i.e. for arbitrary degeneracy.


title: Free boundary problems for a Lotka-Volterra competition system

abstract:
  In this paper we investigate two free boundary problems for a Lotka-Volterra
type competition model in one space dimension. The main objective is to
understand the asymptotic behavior of the two competing species spreading via a
free boundary. We prove a spreading-vanishing dichotomy, namely the two species
either successfully spread to the entire space as time t goes to infinity and
survive in the new environment, or they fail to establish and die out in the
long run. The long time behavior of the solutions and criteria for spreading
and vanishing are also obtained. This paper is an improvement and extension of
J. Guo and C. Wu.


title:
A two-phase flow model of sediment transport: transition from bedload to
  suspended load

abstract:
  The transport of dense particles by a turbulent flow depends on two
dimensionless numbers. Depending on the ratio of the shear velocity of the flow
to the settling velocity of the particles (or the Rouse number), sediment
transport takes place in a thin layer localized at the surface of the sediment
bed (bedload) or over the whole water depth (suspended load). Moreover,
depending on the sedimentation Reynolds number, the bedload layer is embedded
in the viscous sublayer or is larger. We propose here a two-phase flow model
able to describe both viscous and turbulent shear flows. Particle migration is
described as resulting from normal stresses, but is limited by turbulent mixing
and shear-induced diffusion of particles. Using this framework, we
theoretically investigate the transition between bedload and suspended load.


title: Asymptotic variance of grey-scale surface area estimators

abstract:
  Grey-scale local algorithms have been suggested as a fast way of estimating
surface area from grey-scale digital images. Their asymptotic mean has already
been described. In this paper, the asymptotic behaviour of the variance is
studied in isotropic and sufficiently smooth settings, resulting in a general
asymptotic bound. For compact convex sets with nowhere vanishing Gaussian
curvature, the asymptotics can be described more explicitly. As in the case of
volume estimators, the variance is decomposed into a lattice sum and an
oscillating term of at most the same magnitude.


title:
Extendability of quadratic modules over a polynomial extension of an
  equicharacteristic regular local ring

abstract:
  We prove that a quadratic $A[T]$-module $Q$ with Witt index ($Q/TQ$)$ \geq
d$, where $d$ is the dimension of the equicharacteristic regular local ring
$A$, is extended from $A$. This improves a theorem of the second named author
who showed it when $A$ is the local ring at a smooth point of an affine variety
over an infinite field. To establish our result, we need to establish a
Local-Global Principle (of Quillen) for the Dickson--Siegel--Eichler--Roy
(DSER) elementary orthogonal transformations.


title:
Algebroids associated to the groupoid of partially invertible elements
  of a $W^*$-algebra

abstract:
  In the paper we study the algebroid A of the groupoid of partially invertible
elements over the lattice of orthogonal projections of a $W^*$-algebra. In
particular the complex analytic manifold structure of these objects is
investigated. The expressions on the Lie brackets for A and related algebroids
are given in noncommutative operator coordinates in the explicit way. We also
prove statements describing structure of the groupoid of partial isometries and
the frame groupoid of A as well as the structure of their algebroids.


title:
On the Center of Two-parameter Quantum Groups
  $U_{r,s}(\mathfrak{so}_{2n+1})$

abstract:
  The paper mainly considers the center of two-parameter quantum groups
$U_{r,s}(\mathfrak{so}_{2n+1})$ via an analogue of the Harish-Chandra
homomorphism. In the case when $n$ is odd, the Harish-Chandra homomorphism is
not injective in general. When $n$ is even, the Harish-Chandra homomorphism is
injective and the center of two-parameter quantum groups
$U_{r,s}{(\mathfrak{so}_{2n+1})}$ is described, up to isomorphism.


title:
Ground States for Diffusion Dominated Free Energies with Logarithmic
  Interaction

abstract:
  Replacing linear diffusion by a degenerate diffusion of porous medium type is
known to regularize the classical two-dimensional parabolic-elliptic
Keller-Segel model. The implications of nonlinear diffusion are that solutions
exist globally and are uniformly bounded in time. We analyse the stationary
case showing the existence of a unique, up to translation, global minimizer of
the associated free energy. Furthermore, we prove that this global minimizer is
a radially decreasing compactly supported continuous density function which is
smooth inside its support, and it is characterized as the unique compactly
supported stationary state of the evolution model. This unique profile is the
clear candidate to describe the long time asymptotics of the diffusion
dominated classical Keller-Segel model for general initial data.


title:
Lepton Polarization Asymmetries of $H\to\gamma\tau^+\tau^-$ Decays in
  Standard Model

abstract:
  Recently, CMS and ATLAS collaborations at LHC announced a Higgs like particle
with mass near $125$GeV. Regarding this, to explore its intrinsic properties,
different observables are needed to be measured precisely at the LHC for
various decay channels of the Higgs. In this context, we calculate the final
state lepton polarization asymmetries, namely, single lepton polarization
asymmetries ($P_i$) and double lepton polarization asymmetries ($P_{ij}$) in
the SM for radiative semileptonic Higgs decay $H\to\gamma\tau^+\tau^-$. In the
phenomenological analysis of these lepton polarization asymmetries both tree
and loop level diagrams are considered and it is found that these diagrams give
important contributions in the evaluation of said asymmetries. Interestingly,
it is found that in $P_{ij}$ the tree level diagrams contribute separately,
which however, are missing in the calculations of $P_i$ and the lepton
forward-backward asymmetries ($A_{FB}$). Similar to the other observables such
as the decay rate and the lepton forward-backward asymmetries, the
$\tau$-lepton polarization asymmetries would be interesting observables. The
experimental study of these observables will provide a fertile ground to
explore the intrinsic properties of the SM Higgs boson and its dynamics as well
as help us to extract the signatures of the possible new physics beyond the SM.


title:
Application of canonical Hamiltonian formulation to nonlinear
  light-envelope propagations

abstract:
  We first point out it is conditional to apply the variational approach to the
nonlocal nonlinear Schr\"{o}dinger equation (NNLSE), that is, the response
function must be an even function. Different from the variational approach, the
canonical Hamiltonian formulation for the first-order differential system are
used to deal with the problems of the nonlinear light-envelope propagations.
The Hamiltonian of the system modeled by the NNLSE is obtained, which can be
expressed as the sum of the generalized kinetic energy and the generalized
potential. The solitons correspond to extreme points of the generalized
potential. The stabilities of solitons in both local and nonlocal nonlinear
media are also investigated by the analysis of the generalized potential. They
are stable when the potential has minimum, and unstable otherwise.


title:
Additions to the formula lists in "Hypergeometric orthogonal polynomials
  and their $q$-analogues" by Koekoek, Lesky and Swarttouw

abstract:
  This report gives a rather arbitrary choice of formulas for
($q$-)hypergeometric orthogonal polynomials which the author missed while
consulting Chapters 9 and 14 in the book "Hypergeometric orthogonal polynomials
and their $q$-analogues" by Koekoek, Lesky and Swarttouw. The systematics of
these chapters will be followed here, in particular for the numbering of
subsections and of references.


title: Supersonic turbulence in 3D isothermal flow collision

abstract:
  Colliding supersonic bulk flows shape observable properties and internal
physics of various astrophysical objects, like O-star winds, molecular clouds,
galactic sheets, binaries, or gamma-ray bursts. Using numerical simulations, we
show that the bulk flows leave a clear imprint on the collision zone, its mean
properties and the turbulence it naturally develops. Our model setup consists
of 3D head-on colliding isothermal hydrodynamical flows with Mach numbers
between 2 and 43. Simulation results are in line with expectations from
self-similarity: root mean square Mach numbers (Mrms) scale linearly with
upstream Mach numbers, mean densities remain limited to a few times the
upstream density. The density PDF is not log-normal. The turbulence is
inhomogeneous: weaker in the zone center than close to the confining shocks. It
is anisotropic: while Mrms is generally supersonic, Mrms transverse to the
upstream flow is always subsonic. We argue that uniform, isothermal, head-on
colliding flows generally disfavor isotropic, supersonic turbulence. The
anisotropy carries over to other quantities like the density variance - Mach
number relation. Structure functions differ depending on whether they are
computed along a line-of-sight perpendicular or parallel to the upstream flow.
We suggest that such line-of-sight effects should be kept in mind when
interpreting turbulence characteristics derived from observations.


title:
Algorithms and dimensionality reductions for continuous multifacility
  ordered median location problems

abstract:
  In this paper we propose a general methodology for solving a broad class of
continuous, multifacility location problems, in any dimension and with
$\ell_\tau$-norms proposing two different methodologies: 1) by a new second
order cone mixed integer programming formulation and 2) by formulating a
sequence of semidefinite programs that converges to the solution of the
problem; each of these relaxed problems solvable with SDP solvers in polynomial
time. We apply dimensionality reductions of the problems by sparsity and
symmetry in order to be able to solve larger problems.


title: Selective Combining for Hybrid Cooperative Networks

abstract:
  In this study, we consider the selective combining in hybrid cooperative
networks (SCHCNs scheme) with one source node, one destination node and $N$
relay nodes. In the SCHCN scheme, each relay first adaptively chooses between
amplify-and-forward protocol and decode-and-forward protocol on a per frame
basis by examining the error-detecting code result, and $N_c$ ($1\leq N_c \leq
N$) relays will be selected to forward their received signals to the
destination. We first develop a signal-to-noise ratio (SNR) threshold-based
frame error rate (FER) approximation model. Then, the theoretical FER
expressions for the SCHCN scheme are derived by utilizing the proposed SNR
threshold-based FER approximation model. The analytical FER expressions are
validated through simulation results.


title: General Relativistic Calculations for White Dwarf Stars

abstract:
  The mass-radius relations for white dwarf stars are investigated by solving
the Newtonian as well as Tolman-Oppenheimer-Volkoff (TOV) equations for
hydrostatic equilibrium assuming the electron gas to be non-interacting. We
find that the Newtonian limiting mass of $1.4562M_\odot$ is modified to
$1.4166M_\odot$ in the general relativistic case for $^4_2$He (and $^{12}_{\
6}$C) white dwarf stars. Using the same general relativistic treatment, the
critical mass for $^{56}_{26}$Fe white dwarf is obtained as $1.2230M_\odot$. In
addition, departure from the ideal degenerate equation of state (EoS) is
accounted for by considering Salpeter's EoS along with the TOV equations
yielding slightly lower values for the critical masses, namely
$1.4081M_{\odot}$ for $^4_2$He, $1.3916M_{\odot}$ for $^{12}_{\ 6}$C and
$1.1565M_{\odot}$ for $^{56}_{26}$Fe white dwarfs. We also compare the critical
densities for gravitational instability with the neutronization threshold
densities to find that $^4_2$He and $^{12}_{\ 6}$C white dwarf stars are stable
against neutronization with the critical values of $1.4081M_\odot$ and
$1.3916M_{\odot}$, respectively. However the critical masses for $^{16}_{\
8}$O, $^{20}_{10}$Ne, $^{24}_{12}$Mg, $^{28}_{14}$Si, $^{32}_{16}$S and
$^{56}_{26}$Fe white dwarf stars are lower due to neutronization. Corresponding
to their central densities for neutronization thresholds, we obtain their
maximum stable masses due to neutronization by solving the TOV equation coupled
with the Salpeter EoS.


title:
Anisotropy of Conductivity in Bilayer Graphene with Relatively Shifted
  Layers

abstract:
  A transformation of the band structure in bilayer graphene (BLG) with
relatively shifted layers has been studied in the framework of the
tight-binding model. BLG is demonstrated to remain a zero-gap material in the
whole range of experimentally attainable shifts, but the positions of contact
points between the conduction and valence bands depend substantially on the
shift direction. The shift results in a considerable anisotropy of the band
spectrum, which is, in turn, responsible for a substantial (10-20%) anisotropy
of the conductivity in BLG. A possibility of using this anisotropy in
high-sensitive sensors of a mechanical tension and for the generation of a
purely valley current in multivalley anisotropic BLG in the case where both the
average spin and the average current of electrons are equal to zero is
discussed.


title: Intuitionistic Fuzzy Linear Transformations

abstract:
  In this paper, we discussed about the intuitionistic fuzzy linear
transformations (IFLT) and shown that the set of all linear transformations
L(V) defined over an intuitionistic fuzzy vector space V does not form an
vector space. Here we determine the unique intuitionistic fuzzy matrix
associated with an intuitionistic fuzzy linear transformation with respect to
an ordered standard basis for an intuitionistic fuzzy vector space. We
introduced the concept of the inverse of an IFLT.


title: Normality and $K_1$-stability of Roy's elementary orthogonal group

abstract:
  In this paper, we prove the normality of the Roy's elementary orthogonal
group (Dickson--Siegel--Eichler--Roy or DSER group) over a commutative ring
which was introduced by A. Roy in [MR0231844] under some conditions on the
hyperbolic rank. We also establish a stability theorem for $K_1$ of Roy's
group. We obtain a decomposition theorem for the elementary orthogonal group
which is used to deduce the stability theorem.


title: Antipodal Interval-Valued Fuzzy Graphs

abstract:
  Concepts of graph theory have applications in many areas of computer science
including data mining, image segmentation, clustering, image capturing,
networks, etc . An interval-valued fuzzy set is a generalization of the notion
of a fuzzy set. Interval-valued fuzzy models give more precision, flexibility
and compatibility to the system as compared to the fuzzy models. In this paper,
we introduce the concept of antipodal interval - valued fuzzy graph and self
median interval-valued fuzzy graph of the given interval-valued fuzzy graph. We
investigate isomorphism properties of antipodal interval - valued fuzzy graphs.


title:
Finite volumes and mixed Petrov-Galerkin finite elements : the
  unidimensional problem

abstract:
  For Laplace operator in one space dimension, we propose to formulate the
heuristic finite volume method with the help of mixed Petrov-Galerkin finite
elements. Weighting functions for gradient discretization are parameterized by
some universal function. We propose for this function a compatibility
interpolation condition and we prove that such a condition is equivalent to the
inf-sup property when studying stability of the numerical scheme. In the case
of stable scheme and under two distinct hypotheses concerning the regularity of
the solution, we demonstrate convergence of the finite volume method in
appropriate Hilbert spaces and with optimal order of accuracy.


title: Higher Spin AdS$_{d+1}$/CFT$_d$ at One Loop

abstract:
  Following arXiv:1308.2337, we carry out one loop tests of higher spin
AdS$_{d+1}$/CFT$_d$ correspondences for $d\geq 2$. The Vasiliev theories in
AdS$_{d+1}$, which contain each integer spin once, are related to the $U(N)$
singlet sector of the $d$-dimensional CFT of $N$ free complex scalar fields;
the minimal theories containing each even spin once -- to the $O(N)$ singlet
sector of the CFT of $N$ free real scalar fields. Using analytic continuation
of higher spin zeta functions, which naturally regulate the spin sums, we
calculate one loop vacuum energies in Euclidean AdS$_{d+1}$. In even $d$ we
compare the result with the $O(N^0)$ correction to the $a$-coefficient of the
Weyl anomaly; in odd $d$ -- with the $O(N^0)$ correction to the free energy $F$
on the $d$-dimensional sphere. For the theories of integer spins, the
correction vanishes in agreement with the CFT of $N$ free complex scalars. For
the minimal theories, the correction always equals the contribution of one real
conformal scalar field in $d$ dimensions. As explained in arXiv:1308.2337, this
result may agree with the $O(N)$ singlet sector of the theory of $N$ real
scalar fields, provided the coupling constant in the higher spin theory is
identified as $G_N\sim 1/(N-1)$. Our calculations in even $d$ are closely
related to finding the regularized $a$-anomalies of conformal higher spin
theories. In each even $d$ we identify two such theories with vanishing
$a$-anomaly: a theory of all integer spins, and a theory of all even spins
coupled to a complex conformal scalar. We also discuss an interacting UV fixed
point in $d=5$ obtained from the free scalar theory via an irrelevant
double-trace quartic interaction. This interacting large $N$ theory is dual to
the Vasiliev theory in AdS$_6$ where the bulk scalar is quantized with the
alternate boundary condition.


title: Nuclear Structure Functions at Low-$x$ in a Holographic Approach

abstract:
  Nuclear effects in deep inelastic scattering at low$-x$ are
phenomenologically described changing the typical dynamical and/or kinematical
scales characterizing the free nucleon case. In a holographic approach, this
rescaling is an analytical property of the computed structure function
$F_2(x,Q^2)$. This function is given by the sum of a conformal term and of a
contribution due to quark confinement, depending on IR hard-wall parameter
$z_0$ and on the mean square distances, related to a parameter $Q^\prime$,
among quarks and gluons in the target. The holographic structure function per
nucleon in a nucleus $A$ is evaluated showing that a rescaling of the typical
nucleon size, $z_0$ and $Q^\prime$, due to nuclear binding, can be reabsorbed
in a $Q^2$-rescaling scheme. The difference between neutron and proton
structure functions and the effects of the longitudinal structure functions can
also be taken into account. The obtained theoretical results favourably compare
with the experimental data.


title:
Interaction entre math\'ematique et informatique Libre/Open Source par
  le logiciel math\'ematique

abstract:
  This article focuses on the application of model development and opening the
source code available and implemented by the Free Software and Open Source
FLOSS to the instructional and teaching has both mathematics and computer by
the read-write(R/W) of mathematical software, including the most famous cases
are numerical and symbolic computation. The article analysis the development of
the mathematical model of Free/Open Source(math FLOSS) software has proven its
importance in the area of research in mathematics and computer science .
However, although their actual use, is very readable in higher education
courses. We discuss the feasibility of this model to the characteristics of the
domain, actors, interaction they have and the communities they form during the
development of the software. Finally, we propose a mathematical example of
Free/Open Source(Math FlOSS) software as analysis device .


title: Some Thoughts on the Teaching of Mathematics -- ten years later

abstract:
  I describe some deep-seated problems in higher mathematical education, and
give some ideas for their solution -- I advocate a move away from the
traditional introduction of mathematics through calculus, and towards
computation and discrete mathematics.


title:
Coagulation and diffusion: a probabilistic perspective on the
  Smoluchowski PDE

abstract:
  The Smoluchowski coagulation-diffusion PDE is a system of partial
differential equations modelling the evolution in time of mass-bearing Brownian
particles which are subject to short-range pairwise coagulation. This survey
presents a fairly detailed exposition of the kinetic limit derivation of the
Smoluchowski PDE from a microscopic model of many coagulating Brownian
particles that was undertaken in [11]. It presents heuristic explanations of
the form of the main theorem before discussing the proof, and presents key
estimates in that proof using a novel probabilistic technique. The survey's
principal aim is an exposition of this kinetic limit derivation, but it also
contains an overview of several topics which either motivate or are motivated
by this derivation.


title: Quadratic algebra contractions and 2nd order superintegrable systems

abstract:
  Quadratic algebras are generalizations of Lie algebras; they include the
symmetry algebras of 2nd order superintegrable systems in 2 dimensions as
special cases. The superintegrable systems are exactly solvable physical
systems in classical and quantum mechanics. For constant curvature spaces we
show that the free quadratic algebras generated by the 1st and 2nd order
elements in the enveloping algebras of their Euclidean and orthogonal symmetry
algebras correspond one-to-one with the possible superintegrable systems with
potential defined on these spaces. We describe a contraction theory for
quadratic algebras and show that for constant curvature superintegrable
systems, ordinary Lie algebra contractions induce contractions of the quadratic
algebras of the superintegrable systems that correspond to geometrical
pointwise limits of the physical systems. One consequence is that by
contracting function space realizations of representations of the generic
superintegrable quantum system on the 2-sphere (which give the structure
equations for Racah/Wilson polynomials) to the other superintegrable systems
one obtains the full Askey scheme of orthogonal hypergeometric polynomials.


title:
Importance of Tides for Periastron Precession in Eccentric Neutron Star
  - White Dwarf Binaries

abstract:
  Although not nearly as numerous as binaries with two white dwarfs, eccentric
neutron star-white dwarf (NS-WD) binaries are important gravitational-wave (GW)
sources for the next generation of space-based detectors sensitive to low
frequency waves. Here we investigate periastron precession in these sources as
a result of general relativistic, tidal, and rotational effects; such
precession is expected to be detectable for at least some of the detected
binaries of this type. Currently, two eccentric NS-WD binaries are known in the
galactic field, PSR J1141-6545 and PSR B2303+46, both of which have orbits too
wide to be relevant in their current state to GW observations. However,
population synthesis studies predict the existence of a significant Galactic
population of such systems. Though small in most of these systems, we find that
tidally induced periastron precession becomes important when tides contribute
to more than 3% of the total precession rate. For these systems, accounting for
tides when analyzing periastron precession rate measurements can improve
estimates of the WD component mass inferred and, in some cases, will prevent us
from misclassifying the object. However, such systems are rare due to rapid
orbital decay. To aid the inclusion of tidal effects when using periastron
precession as a mass measurement tool, we derive a function that relates the WD
radius and periastron precession constant to the WD mass.


title: Single meson contributions to the muon's anomalous magnetic moment

abstract:
  We develop the formalism to provide an improved estimate for the hadronic
light-by-light correction to the muon's anomalous magnetic moment a_{\mu}, by
considering single meson contributions beyond the leading pseudo-scalar mesons.
We incorporate available experimental input as well as constraints from
light-by-light scattering sum rules to estimate the effects of axial-vector,
scalar, and tensor mesons. We give numerical evaluations for the hadronic
light-by-light contribution of these states to a_{\mu}. The presented formalism
allows to further improve on these estimates, once new data for such meson
states will become available.


title:
Statistics of scattered photons from a driven three-level emitter in a
  one-dimensional open space

abstract:
  We derive the statistics of scattered photons from a $\Lambda$- or
ladder-type three-level emitter (3LE) embedded in a 1D open waveguide. The weak
probe photons in the waveguide are coupled to one of the two allowed
transitions of the 3LE, and the other transition is driven by a control beam.
This system shows electromagnetically induced transparency (EIT) which is
accompanied with the Autler-Townes splitting (ATS) at a strong driving by the
control beam, and some of these effects have been observed recently. We show
that the nature of second-order coherence of the transmitted probe photons near
two-photon resonance changes from bunching to antibunching to constant as
strength of the control beam is ramped up from zero to a higher value where the
ATS appears.


title:
Conventional Superconductivity properties of the ternary boron-nitride
  Nb2BN

abstract:
  Superconducting bulk properties of ternary Nb2 BN are confirmed and are
described by means of magnetization, electronic transport and specific-heat
measurements. BCS conventional super- conductivity is found with Tc = 4.4 K.
Critical fields Hc1 (0)= 93 Oe and Hc2 (0)= 2082 Oe are extrapolated by
magnetic and resistivity measurements. The specific heat data reveals {\gamma}
= 6.3 mJ/mol K2 and {\beta} = 0.293 mJ/mol K4 in good agreement with the BCS
Theory.


title: Analytical model of strange star in the low-mass X-ray binary 4U 1820-30

abstract:
  In this article, we have proposed a model for a realistic strange star under
Tolman VII metric\citep{Tolman1939}. Here the field equations are reduced to a
system of three algebraic equations for anisotropic pressure. Mass, central
density and surface density of strange star in the low-mass X-ray binary 4U
1820-30 has been matched with the observational data according to our model.
Strange materials clearly satisfies the stability condition (i.e. sound
velocities < 1) and TOV-equation. Here also surface red shift of the star has
been found to be within reasonable limit.


title:
Sequential edge-coloring on the subset of vertices of almost regular
  graphs

abstract:
  Let $G$ be a graph and $R\subseteq V(G)$. A proper edge-coloring of a graph
$G$ with colors $1,\ldots,t$ is called an $R$-sequential $t$-coloring if the
edges incident to each vertex $v\in R$ are colored by the colors
$1,\ldots,d_{G}(v)$, where $d_{G}(v)$ is the degree of the vertex $v$ in $G$.
In this note, we show that if $G$ is a graph with $\Delta(G)-\delta(G)\leq 1$
and $\chi^{\prime}(G)=\Delta(G)=r$ ($r\geq 3$), then $G$ has an $R$-sequential
$r$-coloring with $\vert R\vert \geq
\left\lceil\frac{(r-1)n_{r}+n}{r}\right\rceil$, where $n=\vert V(G)\vert$ and
$n_{r}=\vert\{v\in V(G):d_{G}(v)=r\}\vert$. As a corollary, we obtain the
following result: if $G$ is a graph with $\Delta(G)-\delta(G)\leq 1$ and
$\chi^{\prime}(G)=\Delta(G)=r$ ($r\geq 3$), then $\Sigma^{\prime}(G)\leq
\left\lfloor\frac {2n_{r}(2r-1)+n(r-1)(r^{2}+2r-2)}{4r}\right\rfloor$, where
$\Sigma^{\prime}(G)$ is the edge-chromatic sum of $G$.