title: Convex bodies and multiplicities of ideals

abstract:
  We associate convex regions in R^n to m-primary graded sequences of
subspaces, in particular m-primary graded sequences of ideals, in a large class
of local algebras (including analytically irreducible local domains). These
convex regions encode information about Samuel multiplicities. This is in the
spirit of the theory of Grobner bases and Newton polyhedra on one hand, and the
theory of Newton-Okounkov bodies for linear systems on the other hand. We use
this to give a new proof, as well as a generalization of a Brunn-Minkowski
inequality for multiplicities due to Teissier and Rees-Sharp.


title:
Posterior convergence rates for estimating large precision matrices
  using graphical models

abstract:
  We consider Bayesian estimation of a $p\times p$ precision matrix, when $p$
can be much larger than the available sample size $n$. It is well known that
consistent estimation in such ultra-high dimensional situations requires
regularization such as banding, tapering or thresholding. We consider a banding
structure in the model and induce a prior distribution on a banded precision
matrix through a Gaussian graphical model, where an edge is present only when
two vertices are within a given distance. For a proper choice of the order of
graph, we obtain the convergence rate of the posterior distribution and Bayes
estimators based on the graphical model in the $L_{\infty}$-operator norm
uniformly over a class of precision matrices, even if the true precision matrix
may not have a banded structure. Along the way to the proof, we also compute
the convergence rate of the maximum likelihood estimator (MLE) under the same
set of condition, which is of independent interest. The graphical model based
MLE and Bayes estimators are automatically positive definite, which is a
desirable property not possessed by some other estimators in the literature. We
also conduct a simulation study to compare finite sample performance of the
Bayes estimators and the MLE based on the graphical model with that obtained by
using a Cholesky decomposition of the precision matrix. Finally, we discuss a
practical method of choosing the order of the graphical model using the
marginal likelihood function.


title:
Multidimensional sticky Brownian motions as limits of exclusion
  processes

abstract:
  We study exclusion processes on the integer lattice in which particles change
their velocities due to stickiness. Specifically, whenever two or more
particles occupy adjacent sites, they stick together for an extended period of
time, and the entire particle system is slowed down until the ``collision'' is
resolved. We show that under diffusive scaling of space and time such processes
converge to what one might refer to as a sticky reflected Brownian motion in
the wedge. The latter behaves as a Brownian motion with constant drift vector
and diffusion matrix in the interior of the wedge, and reflects at the boundary
of the wedge after spending an instant of time there. In particular, this leads
to a natural multidimensional generalization of sticky Brownian motion on the
half-line, which is of interest in both queuing theory and stochastic portfolio
theory. For instance, this can model a market, which experiences a slowdown due
to a major event (such as a court trial between some of the largest firms in
the market) deciding about the new market leader.


title: CO Abundance Variations in the Orion Molecular Cloud

abstract:
  Infrared stellar photometry from 2MASS and spectral line imaging observations
of 12CO and 13CO J = 1-0 line emission from the FCRAO 14m telescope are
analysed to assess the variation of the CO abundance with physical conditions
throughout the Orion A and Orion B molecular clouds. Three distinct Av regimes
are identified in which the ratio between the 13CO column density and visual
extinction changes corresponding to the photon dominated envelope, the strongly
self-shielded interior, and the cold, dense volumes of the clouds. Within the
strongly self-shielded interior of the Orion A cloud, the 13CO abundance varies
by 100% with a peak value located near regions of enhanced star formation
activity. The effect of CO depletion onto the ice mantles of dust grains is
limited to regions with AV > 10 mag and gas temperatures less than 20 K as
predicted by chemical models that consider thermal-evaporation to desorb
molecules from grain surfaces.
  Values of the molecular mass of each cloud are independently derived from the
distributions of Av and 13CO column densities with a constant 13CO-to-H2
abundance over various extinction ranges. Within the strongly self-shielded
interior of the cloud (Av > 3 mag), 13CO provides a reliable tracer of H2 mass
with the exception of the cold, dense volumes where depletion is important.
However, owing to its reduced abundance, 13CO does not trace the H2 mass that
resides in the extended cloud envelope, which comprises 40-50% of the molecular
mass of each cloud. The implied CO luminosity to mass ratios, M/L_{CO}, are 3.2
and 2.9 for Orion A and Orion B respectively, which are comparable to the value
(2.9), derived from gamma-ray observations of the Orion region. Our results
emphasize the need to consider local conditions when applying CO observations
to derive H2 column densities.


title: Phase diagram of the Two-Component Fractional Quantum Hall Effect

abstract:
  We calculate the phase diagram of the two component fractional quantum Hall
effect as a function of the spin or valley Zeeman energy and the filling
factor, which reveals new phase transitions and phase boundaries spanning many
fractional plateaus. This phase diagram is relevant to the fractional quantum
Hall effect in graphene and in GaAs and AlAs quantum wells, when either the
spin or valley degree of freedom is active.


title:
Subgroup decomposition in Out(F_n): Introduction and Research
  Announcement

abstract:
  This is the introduction to a series of four papers that develop a
decomposition theory for subgroups of Out(F_n) which generalizes the theory for
elements of Out(F_n) found in the work of Bestvina, Feighn, and Handel on the
Tits alternative, and which is analogous to the decomposition theory for
subgroups of mapping class groups found in work of Ivanov. In this introduction
we state the main theorems and we outline the contents of the whole series.


title:
Electromagnetically induced transparency and wide-band wavelength
  conversion in silicon nitride microdisk optomechanical resonators

abstract:
  We demonstrate optomechanically-mediated electromagnetically-induced
transparency and wavelength conversion in silicon nitride (Si3N4) microdisk
resonators. Fabricated devices support whispering gallery optical modes with a
quality factor (Q) of 10^6, and radial breathing mechanical modes with a Q=10^4
and a resonance frequency of 625 MHz, so that the system is in the resolved
sideband regime. Placing a strong optical control field on the red (blue)
detuned sideband of the optical mode produces coherent interference with a
resonant probe beam, inducing a transparency (absorption) window for the probe.
This is observed for multiple optical modes of the device, all of which couple
to the same mechanical mode, and which can be widely separated in wavelength
due to the large bandgap of Si3N4. These properties are exploited to
demonstrate frequency upconversion and downconversion of optical signals
between the 1300 nm and 980 nm bands with a frequency span of 69.4 THz.


title:
The covariant description of electric and magnetic field lines of null
  fields: application to Hopf-Ranada solutions

abstract:
  The concept of electric and magnetic field lines is intrinsically
non-relativistic. Nonetheless, for certain types of fields satisfying certain
geometric properties, field lines can be defined covariantly. More precisely,
two Lorentz-invariant 2D surfaces in spacetime can be defined such that
magnetic and electric field lines are determined, for any observer, by the
intersection of those surfaces with spacelike hyperplanes. An instance of this
type of field is constituted by the so-called Hopf-Ranada solutions of the
source-free Maxwell equations, which have been studied because of their
interesting topological properties, namely, linkage of their field lines. In
order to describe both geometric and topological properties in a succinct
manner, we employ the tools of Geometric Algebra (aka Clifford Algebra) and use
the Clebsch representation for the vector potential as well as the Euler
representation for both magnetic and electric fields. This description is
easily made covariant, thus allowing us to define electric and magnetic field
lines covariantly in a compact geometric language. The definitions of field
lines can be phrased in terms of 2D surfaces in space. We display those
surfaces in different reference frames, showing how those surfaces change under
Lorentz transformations while keeping their topological properties. As a
byproduct we also obtain relations between optical helicity, optical chirality
and generalizations thereof, and their conservation laws.


title: A Tensor Approach to Learning Mixed Membership Community Models

abstract:
  Community detection is the task of detecting hidden communities from observed
interactions. Guaranteed community detection has so far been mostly limited to
models with non-overlapping communities such as the stochastic block model. In
this paper, we remove this restriction, and provide guaranteed community
detection for a family of probabilistic network models with overlapping
communities, termed as the mixed membership Dirichlet model, first introduced
by Airoldi et al. This model allows for nodes to have fractional memberships in
multiple communities and assumes that the community memberships are drawn from
a Dirichlet distribution. Moreover, it contains the stochastic block model as a
special case. We propose a unified approach to learning these models via a
tensor spectral decomposition method. Our estimator is based on low-order
moment tensor of the observed network, consisting of 3-star counts. Our
learning method is fast and is based on simple linear algebraic operations,
e.g. singular value decomposition and tensor power iterations. We provide
guaranteed recovery of community memberships and model parameters and present a
careful finite sample analysis of our learning method. As an important special
case, our results match the best known scaling requirements for the
(homogeneous) stochastic block model.


title:
Key role of hybridization between actinide 5f and oxygen 2p orbitals for
  electronic structure of actinide dioxides

abstract:
  In order to promote our understanding on electronic structure of actinide
dioxides, we construct a tight-binding model composed of actinide $5f$ and
oxygen $2p$ electrons, which is called $f$-$p$ model. After the diagonalization
of the $f$-$p$ model, we compare the eigenenergies in the first Brillouin zone
with the results of relativistic band-structure calculations. Here we emphasize
a key role of $f$-$p$ hybridization in order to understand the electronic
structure of actinide dioxides. In particular, it is found that the position of
energy levels of $\Gamma_7$ and $\Gamma_8$ states determined from crystalline
electric field potentials depends on the $f$-$p$ hybridization. We clarify the
condition on the $f$-$p$ hybridization to explain the electronic structure
which is consistent with the local crystalline electric field state. We briefly
discuss the region of the absolute values of the Slater-Koster integrals for
$f$-$p$ hybridization concerning the appearance of octupole ordering in
NpO$_2$.


title:
Covariance Estimation in High Dimensions via Kronecker Product
  Expansions

abstract:
  This paper presents a new method for estimating high dimensional covariance
matrices. The method, permuted rank-penalized least-squares (PRLS), is based on
a Kronecker product series expansion of the true covariance matrix. Assuming an
i.i.d. Gaussian random sample, we establish high dimensional rates of
convergence to the true covariance as both the number of samples and the number
of variables go to infinity. For covariance matrices of low separation rank,
our results establish that PRLS has significantly faster convergence than the
standard sample covariance matrix (SCM) estimator. The convergence rate
captures a fundamental tradeoff between estimation error and approximation
error, thus providing a scalable covariance estimation framework in terms of
separation rank, similar to low rank approximation of covariance matrices. The
MSE convergence rates generalize the high dimensional rates recently obtained
for the ML Flip-flop algorithm for Kronecker product covariance estimation. We
show that a class of block Toeplitz covariance matrices is approximatable by
low separation rank and give bounds on the minimal separation rank $r$ that
ensures a given level of bias. Simulations are presented to validate the
theoretical bounds. As a real world application, we illustrate the utility of
the proposed Kronecker covariance estimator for spatio-temporal linear least
squares prediction of multivariate wind speed measurements.


title: Massive gravity as a limit of bimetric gravity

abstract:
  Massive gravity may be viewed as a suitable limit of bimetric gravity. The
limiting procedure can lead to an interesting interplay between the
"background" and "foreground" metrics in a cosmological context. The fact that
in bimetric theories one always has two sets of metric equations of motion
continues to have an effect even in the massive gravity limit. Thus, solutions
of bimetric gravity in the limit of vanishing kinetic term are also solutions
of massive gravity, but the contrary statement is not necessarily true.


title: Einstein Static Universe in Exponential $f(T)$ Gravity

abstract:
  We analyze the stability of the Einstein static closed and open universe in
two types of exponential $f(T)$ gravity theories. We show that the stable
solutions exist in these two models. In particular, we find that large regions
of parameter space in equation of state $w=p/\rho$ for the stable universe are
allowed in the $f(T)$ theories.


title:
Partitioned and implicit-explicit general linear methods for ordinary
  differential equations

abstract:
  Implicit-explicit (IMEX) time stepping methods can efficiently solve
differential equa- tions with both stiff and nonstiff components. IMEX
Runge-Kutta methods and IMEX linear multistep methods have been studied in the
literature. In this pa- per we study new implicit-explicit methods of general
linear type (IMEX-GLMs). We develop an order conditions theory for high stage
order partitioned GLMs that share the same abscissae, and show that no
additional coupling order conditions are needed. Consequently, GLMs offer an
excellent framework for the construction of multi-method integration
algorithms. Next, we propose a family of IMEX schemes based on
diagonally-implicit multi-stage integration methods and construct practical
schemes of order three. Numerical results confirm the theoretical findings.


title: Comparing the Ag-content of poltinniks using X-ray fluorescence

abstract:
  X-ray fluorescence experiments have been performed in order to analyze the
elemental composition of four Russian 50-kopek coins ("poltinniks") minted
during 1913, 1921, and 1924. By comparing the intensities of the Ag K{\alpha}
X-rays emitted by the poltinniks, we were able to determine whether the
Ag-content of the coins were equal. One of the goals of this study was to
determine whether or not legislation was carried out that required the
proportions of Ag and Cu used in the minting of coins in 1924 to be identical
to those minted in previous years. Also, the intensities of the Ag K{\alpha}
X-rays emitted by 1924 poltinniks minted in London and Leningrad were compared.
Our results suggest that the percent difference in the proportions of Ag
present in each of the coins is no more than 5.5%.


title: Quantum receivers with squeezing and photon-number-resolving detectors

abstract:
  We propose quantum receivers with optical squeezing and
photon-number-resolving detector (PNRD) for the near-optimal discrimination of
quaternary phase-shift-keyed coherent state signals. The basic scheme is
similar to the previous proposals (e.g. Phys. Rev. A 84, 042328 (2012)) in
which displacement operations, on-off detectors, and electrical feedforward
operations were used. Here we study two types of receivers where one installs
optical squeezings and the other uses PNRDs instead of on-off detectors. We
show that both receivers can attain lower error rates than that by the previous
scheme and in particular, the PNRD based receiver has a significant gain under
the fixed number of feedfoward steps. Moreover, we show that the PNRD based
receiver can suppress the errors due to dark counts, which is not possible by
the on-off detector based receiver with a limited number of feedforwards.


title: Pushdown Exception-Flow Analysis of Object-Oriented Programs

abstract:
  Statically reasoning in the presence of and about exceptions is challenging:
exceptions worsen the well-known mutual recursion between data-flow and
control-flow analysis. The recent development of pushdown control-flow analysis
for the {\lambda}-calculus hints at a way to improve analysis of exceptions: a
pushdown stack can precisely match catches to throws in the same way it matches
returns to calls. This work generalizes pushdown control-flow analysis to
object-oriented programs and to exceptions. Pushdown analysis of exceptions
improves precision over the next best analysis, Bravenboer and Smaragdakis's
Doop, by orders of magnitude. By then generalizing abstract garbage collection
to object-oriented programs, we reduce analysis time by half over pure pushdown
analysis. We evaluate our implementation for Dalvik bytecode on standard
benchmarks as well as several Android applications.


title:
Periodic Variations in the O-C Diagrams of Five Pulsation Frequencies of
  the DB White Dwarf EC 20058-5234

abstract:
  Variations in the pulsation arrival time of five independent pulsation
frequencies of the DB white dwarf EC 20058-5234 individually imitate the
effects of reflex motion induced by a planet or companion but are inconsistent
when considered in unison. The pulsation frequencies vary periodically in a
12.9 year cycle and undergo secular changes that are inconsistent with simple
neutrino plus photon-cooling models. The magnitude of the periodic and secular
variations increases with the period of the pulsations, possibly hinting that
the corresponding physical mechanism is located near the surface of the star.
The phase of the periodic variations appears coupled to the sign of the secular
variations. The standards for pulsation-timing-based detection of planetary
companions around pulsating white dwarfs, and possibly other variables such as
subdwarf B stars, should be re-evaluated. The physical mechanism responsible
for this surprising result may involve a redistribution of angular momentum or
a magnetic cycle. Additionally, variations in a supposed combination frequency
are shown to match the sum of the variations of the parent frequencies to
remarkable precision, an expected but unprecedented confirmation of theoretical
predictions.


title: Random cyclic matrices

abstract:
  We present a Gaussian ensemble of random cyclic matrices on the real field
and study their spectral fluctuations. These cyclic matrices are shown to be
pseudo-symmetric with respect to generalized parity. We calculate the joint
probability distribution function of eigenvalues and the spacing distributions
analytically and numerically. For small spacings, the level spacing
distribution exhibits either a Gaussian or a linear form. Furthermore, for the
general case of two arbitrary complex eigenvalues, leaving out the spacings
among real eigenvalues, and, among complex conjugate pairs, we find that the
spacing distribution agrees completely with the Wigner distribution for Poisson
process on a plane. The cyclic matrices occur in a wide variety of physical
situations, including disordered linear atomic chains and Ising model in two
dimensions. These exact results are also relevant to two-dimensional
statistical mechanics and $\nu$-parametrized quantum chromodynamics.


title:
Stability chart of the triangular points in the elliptic restricted
  problem of three bodies

abstract:
  The possible observations of Trojan-like extrasolar planets stimulate the
deeper understanding of the stability behaviour of the co-orbital resonant
motion. By using Hill's equations and the energy-rate method an analysis of the
stability map of the elliptic restricted three-body problem is performed.
Regions of the $\mu-e$ parameter plane are described numerically and related to
the resonant frequencies of librational motion. Stability and instability can
therefore be obtained by analysing the two independent frequency modes
depending on system parameters. The key role of the long period libration in
determining the structure of the stability is demonstrated and also a stability
mechanism is found that is responsible for extended life time of the test
particle in the unstable domain of the stability map.


title: Random reverse-cyclic matrices and screened harmonic oscillator

abstract:
  We have calculated the joint probability distribution function for random
reverse-cyclic matrices and shown that it is related to an N-body exactly
solvable model. We refer to this well-known model potential as a screened
harmonic oscillator. The connection enables us to obtain all the correlations
among the particle positions moving in a screened harmonic potential. The
density of nontrivial eigenvalues of this ensemble is found to be of the Wigner
form and admits a hole at the origin, in contrast to the semicircle law of the
Gaussian orthogonal ensemble of random matrices. The spacing distributions
assume different forms ranging from Gaussian-like to Wigner.


title: Three dimensional Eddington--inspired Born--Infeld gravity: solutions

abstract:
  Three dimensional Eddington-inspired Born--Infeld gravity is studied with the
goal of finding new solutions. Beginning with cosmology, we obtain analytical
and numerical solutions for the scale factor, a(t), in spatially flat (k=0) and
spatially curved (k=+1,-1) Friedmann-Roberston-Walker universes with (i)
pressureless dust (P=0) and (ii) perfect fluid (P=\rho/2), as matter sources.
When the theory parameter \kappa>0, our cosmological solutions are generically
singular (except for the open universe, with a specific condition). On the
other hand, for \kappa<0 we do find non-singular cosmologies. We then move on
towards finding static, circularly symmetric line elements with matter obeying
(i) p=0 and (ii) p=\rho/2. For p=0, the solution found is nonsingular for
\kappa<0 with the matter--stress--energy representing inhomogeneous dust. For
p=\rho/2 we obtain nonsingular solutions, for all \kappa, and discuss some
interesting characteristics of these solutions. Finally, we look at the rather
simple p=-\rho case where the solutions are either de Sitter or anti-de Sitter
or flat spacetime.


title: Planar Hypohamiltonian Graphs on 40 Vertices

abstract:
  A graph is hypohamiltonian if it is not Hamiltonian, but the deletion of any
single vertex gives a Hamiltonian graph. Until now, the smallest known planar
hypohamiltonian graph had 42 vertices, a result due to Araya and Wiener. That
result is here improved upon by 25 planar hypohamiltonian graphs of order 40,
which are found through computer-aided generation of certain families of planar
graphs with girth 4 and a fixed number of 4-faces. It is further shown that
planar hypohamiltonian graphs exist for all orders greater than or equal to 42.
If Hamiltonian cycles are replaced by Hamiltonian paths throughout the
definition of hypohamiltonian graphs, we get the definition of hypotraceable
graphs. It is shown that there is a planar hypotraceable graph of order 154 and
of all orders greater than or equal to 156. We also show that the smallest
hypohamiltonian planar graph of girth 5 has 45 vertices.


title:
Orbital parameters, chemical composition, and magnetic field of the Ap
  binary HD 98088

abstract:
  HD 98088 is a synchronised, double-lined spectroscopic binary system with a
magnetic Ap primary component and an Am secondary component. We study this rare
system using high-resolution MuSiCoS spectropolarimetric data, to gain insight
into the effect of binarity on the origin of stellar magnetism and the
formation of chemical peculiarities in A-type stars. Using a new collection of
29 high-resolution Stokes VQU spectra we re-derive the orbital and stellar
physical parameters and conduct the first disentangling of spectroscopic
observations of the system to conduct spectral analysis of the individual
stellar components. From this analysis we determine the projected rotational
velocities of the stars and conduct a detailed chemical abundance analysis of
each component using both the SYNTH3 and ZEEMAN spectrum synthesis codes. The
surface abundances of the primary component are typical of a cool Ap star,
while those of the secondary component are typical of an Am star. We present
the first magnetic analysis of both components using modern data. Using
Least-Squares Deconvolution, we extract the longitudinal magnetic field
strength of the primary component, which is observed to vary between +1170 and
-920 G with a period consistent with the orbital period. There is no field
detected in the secondary component. The magnetic field in the primary is
predominantly dipolar, with the positive pole oriented approximately towards
the secondary.


title:
Long distance entanglement in one-dimensional quantum systems under
  sinusoidal deformation

abstract:
  We investigate entanglement generation in one-dimensional quantum spin
systems with the sinusoidal deformation. In the system, the energy scale of
each local term in the Hamiltonian is modified according to a
position-dependent function \sin^\alpha[\frac{\pi}{N} (x - \frac{1}{2})], where
x is the position of the local term and N is the length of the system. We show
that at zero temperature the system with \alpha \ge 2 is able to generate a
sizable entanglement between two spins at open edges even when the two spins
are infinitely far apart. This long-distance entanglement is rather robust
against thermal fluctuations and survives up to a temperature that decays with
the system size slowly, in an algebraic form.


title: Pseudo-Hermitian random matrix theory

abstract:
  Complex extension of quantum mechanics and the discovery of pseudo-unitarily
invariant random matrix theory has set the stage for a number of applications
of these concepts in physics. We briefly review the basic ideas and present
applications to problems in statistical mechanics where new results have become
possible. We have found it important to mention the precise directions where
advances could be made if further results become available.


title: On the Capacity of Channels with Timing Synchronization Errors

abstract:
  We consider a new formulation of a class of synchronization error channels
and derive analytical bounds and numerical estimates for the capacity of these
channels. For the binary channel with only deletions, we obtain an expression
for the symmetric information rate in terms of subsequence weights which
reduces to a tight lower bound for small deletion probabilities. We are also
able to exactly characterize the Markov-1 rate for the binary channel with only
replications. For a channel that introduces deletions as well as replications
of input symbols, we design approximating channels that parameterize the state
space and show that the information rates of these approximate channels
approach that of the deletion-replication channel as the state space grows. For
the case of the channel where deletions and replications occur with the same
probabilities, a stronger result in the convergence of mutual information rates
is shown. The numerous advantages this new formulation presents are explored.


title: Hereditary unigraphs and Erd\H{o}s--Gallai equalities

abstract:
  We give characterizations of the structure and degree sequences of hereditary
unigraphs, those graphs for which every induced subgraph is the unique
realization of its degree sequence. The class of hereditary unigraphs properly
contains the threshold and matrogenic graphs, and the characterizations
presented here naturally generalize those known for these other classes of
graphs.
  The degree sequence characterization of hereditary unigraphs makes use of the
list of values $k$ for which the $k$th Erd\H{o}s--Gallai inequality holds with
equality for a graphic sequence. Using the canonical decomposition of
Tyshkevich, we show how this list describes structure common among all
realizations of an arbitrary graphic sequence.


title: Conformal Fitness and Uniformization of Holomorphically Moving Disks

abstract:
  Let $\{U_t \}_{t \in {\mathbb D}}$ be a family of topological disks on the
Riemann sphere containing the origin 0 whose boundaries undergo a holomorphic
motion over the unit disk $\mathbb D$. We study the question of when there
exists a family of Riemann maps $g_t:({\mathbb D},0) \to (U_t,0)$ which depends
holomorphically on the parameter $t$. We give five equivalent conditions which
provide analytic, dynamical and measure-theoretic characterizations for the
existence of the family $\{g_t \}_{t \in {\mathbb D}}$, and explore the
consequences.


title:
Adiabatic measurements of magneto-caloric effects in pulsed high
  magnetic fields up to 55 T

abstract:
  Magneto-caloric effects (MCEs) measurement system in adiabatic condition is
proposed to investigate the thermodynamic properties in pulsed magnetic fields
up to 55 T. With taking the advantage of the fast field- sweep rate in pulsed
field, adiabatic measurements of MCEs were carried out at various temperatures.
To obtain the prompt response of the thermometer in the pulsed field, a thin
film thermometer is grown directly on the sample surfaces. The validity of the
present setup was demonstrated in the wide temperature range through the
measurements on Gd at about room temperature and on Gd3Ga5O12 at low
temperatures. The both results show reasonable agreement with the data reported
earlier. By comparing the MCE data with the specific heat data, we could
estimate the entropy as functions of magnetic field and temperature. The
results demonstrate the possibility that our approach can trace the change in
transition temperature caused by the external field.


title:
Direction dependence of the power spectrum and its effect on the Cosmic
  Microwave Background Radiation

abstract:
  We study several anisotropic inflationary models and their implications for
the observed violation of statistical isotropy in the CMBR data. In two of
these models the anisotropy decays very quickly during the inflationary phase
of expansion. We explicitly show that these models lead to violation of
isotropy only for low l CMBR modes. Our primary aim is to fit the observed
alignment of l=2,3 multipoles to the theoretical models. We use two measures,
based on the power tensor, which contains information about the alignment of
each multipole, to quantify the anisotropy in data. One of the measures uses
the dispersion in eigenvalues of the power tensor. We also define another
measure which tests the overall correlation between two different multipoles.
We perturbatively compute these measures of anisotropy and fix the theoretical
parameters by making a best fit to l=2,3 multipoles. We show that some of the
models studied are able to consistently explain the observed violation of
statistical isotropy.


title: A Weak Galerkin Finite Element Method for the Stokes Equations

abstract:
  This paper introduces a weak Galerkin (WG) finite element method for the
Stokes equations in the primary velocity-pressure formulation. This WG method
is equipped with stable finite elements consisting of usual polynomials of
degree $k\ge 1$ for the velocity and polynomials of degree $k-1$ for the
pressure, both are discontinuous. The velocity element is enhanced by
polynomials of degree $k-1$ on the interface of the finite element partition.
All the finite element functions are discontinuous for which the usual gradient
and divergence operators are implemented as distributions in properly-defined
spaces. Optimal-order error estimates are established for the corresponding
numerical approximation in various norms. It must be emphasized that the WG
finite element method is designed on finite element partitions consisting of
arbitrary shape of polygons or polyhedra which are shape regular.


title: Some classes of weighted conditional type operators and their spectra

abstract:
  In this paper, some ?-classes of weighted conditional expectation type
operators, such as A-class, ?-A-class and quasi-?-A classes on L2(?) are
investigated. Also, the spectrum, point spectrum and spectral radius of these
operators are computed.


title: Reduction of $\tau$-tilting modules and torsion pairs

abstract:
  The class of support $\tau$-tilting modules was introduced recently by
Adachi, Iyama and Reiten. These modules complete the class of tilting modules
from the point of view of mutations. Given a finite dimensional algebra $A$, we
study all basic support $\tau$-tilting $A$-modules which have given basic
$\tau$-rigid $A$-module as a direct summand. We show that there exist an
algebra $C$ such that there exists an order-preserving bijection between these
modules and all basic support $\tau$-tilting $C$-modules; we call this process
$\tau$-tilting reduction. An important step in this process is the formation of
$\tau$-perpendicular categories which are analogs of ordinary perpendicular
categories. Finally, we show that $\tau$-tilting reduction is compatible with
silting reduction and 2-Calabi-Yau reduction in appropiate triangulated
categories.


title: Population Genetics of Rare Variants and Complex Diseases

abstract:
  Identifying drivers of complex traits from the noisy signals of genetic
variation obtained from high throughput genome sequencing technologies is a
central challenge faced by human geneticists today. We hypothesize that the
variants involved in complex diseases are likely to exhibit non-neutral
evolutionary signatures. Uncovering the evolutionary history of all variants is
therefore of intrinsic interest for complex disease research. However, doing so
necessitates the simultaneous elucidation of the targets of natural selection
and population-specific demographic history. Here we characterize the action of
natural selection operating across complex disease categories, and use
population genetic simulations to evaluate the expected patterns of genetic
variation in large samples. We focus on populations that have experienced
historical bottlenecks followed by explosive growth (consistent with most human
populations), and describe the differences between evolutionarily deleterious
mutations and those that are neutral. Genes associated with several complex
disease categories exhibit stronger signatures of purifying selection than
non-disease genes. In addition, loci identified through genome-wide association
studies of complex traits also exhibit signatures consistent with being in
regions recurrently targeted by purifying selection. Through simulations, we
show that population bottlenecks and rapid growth enables deleterious rare
variants to persist at low frequencies just as long as neutral variants, but
low frequency and common variants tend to be much younger than neutral
variants. This has resulted in a large proportion of modern-day rare alleles
that have a deleterious effect on function, and that potentially contribute to
disease susceptibility.


title: Thin film barristor: a gate tunable vertical graphene-pentacene device

abstract:
  We fabricate a vertical thin-film barristor device consisting of highly doped
silicon (gate), 300 nm SiO2 (gate dielectric), monolayer graphene, pentacene,
and a gold top electrode. We show that the current across the device is
modulated by the Fermi energy level of graphene, tuned with an external gate
voltage. We interpret the device current within the thermionic emission theory,
showing a modulation of the energy barrier between graphene and pentacene as
large as 300meV.


title: Bayesian Nonparametric Dictionary Learning for Compressed Sensing MRI

abstract:
  We develop a Bayesian nonparametric model for reconstructing magnetic
resonance images (MRI) from highly undersampled k-space data. We perform
dictionary learning as part of the image reconstruction process. To this end,
we use the beta process as a nonparametric dictionary learning prior for
representing an image patch as a sparse combination of dictionary elements. The
size of the dictionary and the patch-specific sparsity pattern are inferred
from the data, in addition to other dictionary learning variables. Dictionary
learning is performed directly on the compressed image, and so is tailored to
the MRI being considered. In addition, we investigate a total variation penalty
term in combination with the dictionary learning model, and show how the
denoising property of dictionary learning removes dependence on regularization
parameters in the noisy setting. We derive a stochastic optimization algorithm
based on Markov Chain Monte Carlo (MCMC) for the Bayesian model, and use the
alternating direction method of multipliers (ADMM) for efficiently performing
total variation minimization. We present empirical results on several MRI,
which show that the proposed regularization framework can improve
reconstruction accuracy over other methods.


title:
Projection methods and discrete gradient methods for preserving first
  integrals of ODEs

abstract:
  In this paper we study linear projection methods for approximating the
solution and simultaneously preserving first integrals of autonomous ordinary
differential equations. We show that (linear) projection methods are a subset
of discrete gradient methods. In particular, each projection method is
equivalent to a class of discrete gradient methods (where the choice of
discrete gradient is arbitrary) and earlier results for discrete gradient
methods also apply to projection methods. Thus we prove that for the case of
preserving one first integral, under certain mild conditions, the numerical
solution for a projection method exists and is locally unique, and preserves
the order of accuracy of the underlying method.
  In the case of preserving multiple first integrals the relationship between
projection methods and discrete gradient methods persists. Moreover, numerical
examples show that similar existence and order results should also hold for the
multiple integral case.
  For completeness we show how existing projection methods from the literature
fit into our general framework.


title: Two new standing solitary waves in shallow water

abstract:
  In this paper, the closed-form analytic solutions of two new Faraday's
standing solitary waves due to the parametric resonance of liquid in a vessel
vibrating vertically with a constant frequency are given for the first time.
Using a model based on the symmetry of wave elevation and the linearized
Boussinesq equation, we gain the closed-form wave elevations of the two kinds
of non-monotonically decaying standing solitary waves with smooth crest and the
even or odd symmetry. All of them have never been reported, to the best of our
knowledge. Besides, they can well explain some experimental phenomena. All of
these are helpful to deepen and enrich our understandings about standing
solitary waves and Faraday's wave.


title:
A new dynamo pattern revealed by the tilt angle of bipolar sunspot
  groups

abstract:
  We obtain the latitude-time distribution of the averaged tilt angle of solar
bipoles. For large bipoles, which are mainly bipolar sunspot groups, the
spatially averaged tilt angle is positive in the Northern solar hemisphere and
negative in the Southern, with modest variations during course of the solar
cycle. We consider the averaged tilt angle to be a tracer for a crucial element
of the solar dynamo, i.e. the regeneration rate of poloidal large-scale
magnetic field from toroidal. The value of the tilt obtained crudely
corresponds to a regeneration factor corresponding to about 10% of r.m.s.
velocity of solar convection. These results develop findings of Kosovichev and
Stenflo (2012) concerning Joy's law, and agree with the usual expectations of
solar dynamo theory. Quite surprisingly, we find a pronounced deviation from
these properties for smaller bipoles, which are mainly solar ephemeral regions.
They possess tilt angles of approximately the same absolute value, but of
opposite sign compared to that of the large bipoles. Of course, the tilt data
for small bipoles are less well determined than those for large bipoles;
however they remain robust under various modifications of the data processing.


title: On Topological Defects and Cosmological Constant

abstract:
  Einstein introduced Cosmological Constant in his field equations in an ad hoc
manner. Cosmological constant plays the role of vacuum energy of the universe
which is responsible for the accelerating expansion of the universe. To give
theoretical support it remains an elusive goal to modern physicists. We provide
a prescription to obtain cosmological constant from the phase transitions of
the early universe when topological defects, namely monopole might have
existed.


title:
An Adaptive Total Variation Algorithm for Computing the Balanced Cut of
  a Graph

abstract:
  We propose an adaptive version of the total variation algorithm proposed in
[3] for computing the balanced cut of a graph. The algorithm from [3] used a
sequence of inner total variation minimizations to guarantee descent of the
balanced cut energy as well as convergence of the algorithm. In practice the
total variation minimization step is never solved exactly. Instead, an accuracy
parameter is specified and the total variation minimization terminates once
this level of accuracy is reached. The choice of this parameter can vastly
impact both the computational time of the overall algorithm as well as the
accuracy of the result. Moreover, since the total variation minimization step
is not solved exactly, the algorithm is not guarantied to be monotonic. In the
present work we introduce a new adaptive stopping condition for the total
variation minimization that guarantees monotonicity. This results in an
algorithm that is actually monotonic in practice and is also significantly
faster than previous, non-adaptive algorithms.


title: Text Steganographic Approaches: A Comparison

abstract:
  This paper presents three novel approaches of text steganography. The first
approach uses the theme of missing letter puzzle where each character of
message is hidden by missing one or more letters in a word of cover. The
average Jaro score was found to be 0.95 indicating closer similarity between
cover and stego file. The second approach hides a message in a wordlist where
ASCII value of embedded character determines length and starting letter of a
word. The third approach conceals a message, without degrading cover, by using
start and end letter of words of the cover. For enhancing the security of
secret message, the message is scrambled using one-time pad scheme before being
concealed and cipher text is then concealed in cover. We also present an
empirical comparison of the proposed approaches with some of the popular text
steganographic approaches and show that our approaches outperform the existing
approaches.


title: On the orbital stability of fractional Schr\"{o}dinger equations

abstract:
  We show the existence of ground state and orbital stability of standing waves
of fractional Schr\"{o}dinger equations with power type nonlinearity. For this
purpose we establish the uniqueness of weak solutions.


title: Cellules de Calogero-Moser

abstract:
  Using the representation theory of Cherednik algebras at t=0 and a Galois
covering of the Calogero-Moser space, we define the notions of left, right and
two-sided Calogero-Moser cells for any finite complex reflection group. To each
Caloger-Moser two-sided cell is associated a Calogero-Moser family, while to
each Calogero-Moser left cell is associated a Calogero-Moser cellular
representation. We study properties of these objects and we conjecture that,
whenever the reflection group is real (i.e. is a Coxeter group), these notions
coincide with the one of Kazhdan-Lusztig left, right and two-sided cells,
Kazhdan-Lusztig families and Kazhdan-Lusztig cellular representations.


title: Constructible characters and b-invariants

abstract:
  To each finite Coxeter system (W,S) and to each weight function L, Lusztig
has defined the notions of constructible characters and of Lusztig families of
W, using the so-called J-induction. Whenever L is constant, and using a general
argument, Lusztig has shown that all Lusztig family contains a unique character
with minimal b-invariant, and that every constructible character contains an
irreducible constituent with minimal b-invariant. We show in this paper that
this can be generalized to the case where L is not constant: our proof is by a
case-by-case analysis.


title:
The unlikely rise of masking interferometry: leading the way with 19th
  century technology

abstract:
  The exquisite precision delivered by interferometric techniques is rapidly
being applied to more and more branches of optical astronomy. One particularly
successful strategy to obtain structures at the scale of the diffraction limit
is Aperture Masking Interferometry, which is presently experience a golden age
with implementations at a host of large telescopes around the world. This
startlingly durable technique, which turns 144 years old this year, presently
sets the standard for the recovery of faint companions within a few resolution
elements from the core of a stellar point spread function. This invited review
will give a historical introduction and overview of the modern status of the
technique, the science being delivered, and prospects for new advances and
applications.


title: Conservation Laws and Thermodynamic Efficiencies

abstract:
  We show that generic systems with a single relevant conserved quantity reach
the Carnot efficiency in the thermodynamic limit. Such a general result is
illustrated by means of a diatomic chain of hard-point elastically colliding
particles where the total momentum is the only relevant conserved quantity.


title: Extrinsic noise driven phenotype switching in a self-regulating gene

abstract:
  Due to inherent noise in intracellular networks cellular decisions can be
random, so genetically identical cells can display different phenotypic
behavior even in identical environments. Most previous work in understanding
the decision-making process has focused on the role of intrinsic noise in these
systems. Yet, especially in the high copy-number regime, extrinsic noise has
been shown to be much more significant. Here, using a prototypical example of a
bistable self-regulating gene model, we develop a theoretical framework
describing the combined effect of intrinsic and extrinsic noise on the dynamics
of stochastic genetic switches. Employing our theory and Monte Carlo
simulations, we show that extrinsic noise not only significantly alters the
lifetimes of the phenotypic states, but can induce bistability in unexpected
regions of parameter space, and may fundamentally change the escape mechanism.
These results have implications for interpreting experimentally observed
heterogeneity in cellular populations and for stochastic modeling of cellular
decision processes.


title: Rickart Modules Relative to Goldie Torsion Theory

abstract:
  Let $R$ be an arbitrary ring with identity and $M$ a right $R$-module with
$S=$ End$_R(M)$. Let $Z_2(M)$ be the second singular submodule of $M$. In this
paper, we define Goldie Rickart modules by utilizing the endomorphisms of a
module. The module $M$ is called Goldie Rickart if for any $f\in S$,
$f^{-1}(Z_2(M))$ is a direct summand of $M$. We provide several
characterizations of Goldie Rickart modules and study their properties. Also we
present that semisimple rings and right $\Sigma$-$t$-extending rings admit some
characterizations in terms of Goldie Rickart modules.


title:
Optimality of qubit purification protocols in the presence of
  imperfections

abstract:
  Quantum control is an essential tool for the operation of quantum
technologies such as quantum computers, simulators, and sensors. Although there
are sophisticated theoretical tools for developing quantum control protocols,
formulating optimal protocols while incorporating experimental conditions
remains a challenge. In this paper, motivated by recent advances in realization
of real-time feedback control in circuit quantum electrodynamics systems, we
study the effect of experimental imperfections on the optimality of qubit
purification protocols. Specifically, we find that the optimal control
solutions in the presence of detector inefficiency and non-negligible
decoherence can be significantly different from the known solutions to
idealized dynamical models. In addition, we present a simplified form of the
verification theorem to examine the global optimality of a control protocol.


title: Effective-field theory study of the dynamical Ising-type thin films

abstract:
  The stationary state solutions of the Ising-type thin films with different
layers in the presence of an external oscillatory field have been examined
within the effective field theory. The exhibition focuses on understanding of
the external field frequency and amplitude effect on the overall behavior of
system for several powerful treatments. The particular attention has been paid
on the dynamical parametric evolution of the special point at which the
critical temperature of the three-dimensional infinite bulk system, where the
surface and the modified exchange parameter are of no importance. Important
characteristics of the films, such as surface enhancement phenomenon, effect of
thickness on the dynamic process etc. have been introduced together with well
known other characteristics. An attempt has been made to explain the relations
between the competing time scales (intrinsic microscopic relaxation time of the
system and the time period of the external oscillatory field) and frequency
dispersion of the critical temperature coordinate of the special point.


title: LoCuSS: The Mass Density Profile of Massive Galaxy Clusters at z=0.2

abstract:
  We present a stacked weak-lensing analysis of an approximately mass-selected
sample of 50 galaxy clusters at 0.15<z<0.3, based on observations with
Suprime-Cam on the Subaru Telescope. We develop a new method for selecting
lensed background galaxies from which we estimate that our sample of red
background galaxies suffers just 1% contamination. We detect the stacked
tangential shear signal from the full sample of 50 clusters, based on this red
sample of background galaxies, at a total signal-to-noise ratio of S/N=32.7.
The Navarro-Frenk-White model is an excellent fit to the data, yielding sub-10%
statistical precision on mass and concentration:
Mvir=7.19^{+0.53}_{-0.50}\times10^{14}h^{-1}Msol, cvir=5.41^{+0.49}_{-0.45}
(c_{200}=4.22^{+0.40}_{-0.36}). Tests of a range of possible systematic errors,
including shear calibration and stacking-related issues, indicate that they are
sub-dominant to the statistical errors. The concentration parameter obtained
from stacking our approximately mass-selected cluster sample is broadly in line
with theoretical predictions. Moreover, the uncertainty on our measurement is
comparable with the differences between the different predictions in the
literature. Overall our results highlight the potential for stacked
weak-lensing methods to probe the mean mass density profile of cluster-scale
dark matter halos with upcoming surveys, including Hyper-Suprime-Cam, Dark
Energy Survey, and KIDS.


title:
Three-phase plane composites of minimal elastic stress energy:
  High-porosity structures

abstract:
  The paper establishes exact lower bound on the effective elastic energy of
two-dimensional, three-material composite subjected to the homogeneous,
anisotropic stress. It is assumed that the materials are mixed with given
volume fractions and that one of the phases is degenerated to void, i.e. the
effective composite is porous. Explicit formula for the energy bound is
obtained using the translation method enhanced with additional inequality
expressing certain property of stresses. Sufficient optimality conditions of
the energy bound are used to set the requirements which have to be met by the
stress fields in each phase of optimal effective material regardless of the
complexity of its microstructural geometry. We show that these requirements are
fulfilled in a special class of microgeometries, so-called laminates of a rank.
Their optimality is elaborated in detail for structures with significant amount
of void, also referred to as high-porosity structures. It is shown that
geometrical parameters of optimal multi-rank, high-porosity laminates are
different in various ranges of volume fractions and anisotropy level of
external stress. Non-laminate, three-phase microstructures introduced by other
authors and their optimality in high-porosity regions is also discussed by
means of the sufficient conditions technique. Conjectures regarding
low-porosity regions are presented, but full treatment of this issue is
postponed to a separate publication. The corresponding "G-closure problem" of a
three-phase isotropic composite is also addressed and exact bounds on effective
isotropic properties are explicitly determined in these regions where the
stress energy bound is optimal.


title: Lorentz violation in neutron and allowed nuclear beta decay

abstract:
  We explore the possibility that the weak interaction violates Lorentz, and in
particular rotational, invariance in neutron and allowed nuclear beta decay. A
broad class of Lorentz-violating effects is considered, in which the standard
propagator of the W-boson acquires an additional Lorentz-violating tensor. The
general decay rate for allowed beta decay that incorporates such a modified
propagator is derived. The resulting Lorentz-violating signals are discussed
for the different types of beta-decay transitions, Fermi, Gamow-Teller, and
mixed. We study the implications of our formalism for dedicated beta-decay
experiments. We give a short overview of the few relevant experiments that have
been performed or are ongoing.


title: Quantum correlations which imply causation

abstract:
  In ordinary, non-relativistic, quantum physics, time enters only as a
parameter and not as an observable: a state of a physical system is specified
at a given time and then evolved according to the prescribed dynamics. While
the state can, and usually does, extend across all space, it is only defined at
one instant of time, in conflict with special relativity where space and time
are treated on an equal footing. Here we ask what would happen if we defined
the notion of the quantum density matrix for multiple spatial and temporal
measurements. We introduce the concept of a pseudo-density matrix which treats
space and time indiscriminately. This matrix in general fails to be positive
for timelike separated measurements, motivating us to define a measure of
causality that discriminates between spacelike and timelike correlations.
Important properties of this measure, such as monotonicity under local
operations, are proved. Two qubit NMR experiments are presented that illustrate
how a temporal pseudo-density matrix approaches a genuinely allowed density
matrix as the amount of decoherence is increased between two consecutive
measurements.


title: Boundary Behaviors for General Off-shell Amplitudes in Yang-Mills Theory

abstract:
  In this article, we analyze the boundary behaviors of pure Yang-Mills
amplitudes under adjacent and non adjacent BCFW shifts in Feynman gauge. We
introduce reduced vertexes for Yang-Mills fields, prove that these reduced
vertexes are equivalent to the original vertexes as for the study of boundary
behaviors, which greatly simplifies our analysis of boundary behaviors.
Boundary behaviors for adjacent shifts are readily obtained using reduced
vertexes. Then we prove a theorem on permutation sum and use it to prove the
improved boundary behaviors for non-adjacent shifts. Based on the boundary
behaviors, we find that it is possible to generalize BCFW recursion relation to
calculate general tree level off shell amplitudes.


title: Overview of MHz air shower radio experiments and results

abstract:
  In this paper, I present a review of the main results obtained in the last 10
years in the field of radio-detection of cosmic-ray air showers in the MHz
range. All results from all experiments cannot be reported here so that I will
focus on the results more than on the experiments themselves. Modern
experiments started in 2003 with CODALEMA and LOPES. In 2006, small-size
autonomous prototypes setup were installed at the Pierre Auger Observatory
site, to help the design of the Auger Engineering Radio Array (AERA). We will
discuss the principal aspects of the radio data analysis and the determination
of the primary cosmic ray characteristics: the arrival direction, the lateral
distribution of the electric field, the correlation with the primary energy,
the emission mechanisms and the sensitivity to the composition of the cosmic
rays.


title:
Initial value problem of evolution equations defined by lattice
  operators

abstract:
  We propose dynamical systems defined on algebra of lattices, which we call
`lattice equations'. We give exact general solutions of initial value problems
for a class of lattice equations, and evaluate the complexity of the solutions.
Moreover we discuss the relationship between those equations and binary
cellular automata.


title: Slight compressibility and sensitivity to changes in Poisson's ratio

abstract:
  Finite Element simulations of rubbers and biological soft tissue usually
assume that the material being deformed is slightly compressible. It is shown
here that in shearing deformations the corresponding normal stress distribution
can exhibit extreme sensitivity to changes in Poisson's ratio. These changes
can even lead to a reversal of the usual Poynting effect. Therefore the usual
practice of arbitrarily choosing a value of Poisson's ratio when numerically
modelling rubbers and soft tissue will, almost certainly, lead to a significant
difference between the simulated and actual normal stresses in a sheared block
because of the difference between the assumed and actual value of Poisson's
ratio. The worrying conclusion is that simulations based on arbitrarily
specifying Poisson's ratio close to 1/2 cannot accurately predict the normal
stress distribution even for the simplest of shearing deformations. It is shown
analytically that this sensitivity is due to the small volume changes which
inevitably accompany all deformations of rubber-like materials. To minimise
these effects, great care should be exercised to accurately determine Poisson's
ratio before simulations begin.


title: Topological pumping in class-D superconducting wires

abstract:
  We study adiabatic pumping at a normal metal/class-D superconductor hybrid
interface when superconductivity is induced through the proximity effect in a
spin-orbit coupled nanowire in the presence of a tilted Zeeman field. When the
induced order parameter in the nanowire is non-uniform, the phase diagram has
isolated trivial regions surrounded by topological ones. We show that in this
case the pumped charge is quantized in units of the elementary charge $e$ and
has a topological nature.


title:
Steenrod squares on Intersection cohomology and a conjecture of M.
  Goresky and W. Pardon

abstract:
  We prove a conjecture raised by M. Goresky and W. Pardon, concerning the
range of validity of the perverse degree of Steenrod squares in intersection
cohomology. This answer turns out of importance for the definition of
characteristic classes in the framework of intersection cohomology.
  For this purpose, we present a construction of ${\rm cup}_{i}$-products on
the cochain complex, built on the blow-up of some singular simplices and
introduced in a previous work. We extend to this setting the classical
properties of the associated Steenrod squares, including Adem and Cartan
relations, for any generalized perversities. In the case of a pseudomanifold,
we prove that our definition coincides with M. Goresky's definition.
  Several examples of concrete computation of perverse Steenrod squares are
given, including the case of isolated singularities and, more especially, we
describe the Steenrod squares on the Thom space of a vector bundle, in function
of the Steenrod squares of the basis and the Stiefel-Whitney classes. We detail
also an example of a non trivial square, $\sq^2\colon H_{\ bar{p}}\to H_{\
bar{p}+2}$, whose information is lost if we consider it as values in $H_{2\
bar{p}}$, showing the interest of the Goresky and Pardon's conjecture.


title:
RandFile package for Mathematica for accessing file-based sources of
  randomness

abstract:
  We present a package for Mathematica computer algebra system which allows the
exploitation of local files as sources of random data. We provide the
description of the package and illustrate its usage by showing some examples.
We also compare the provided functionality with alternative sources of
randomness, namely a built-in pseudo-random generator and the package for
accessing hardware true random number generators.

categories: physics.comp-ph cs.MS physics.data-an quant-ph


title:
Transverse Killing and twistor spinors associated to the basic Dirac
  operators

abstract:
  We study the interplay between basic Dirac operator and transverse Killing
and twistor spinors. In order to obtain results for general Riemannian
foliations with bundle-like metric we consider transverse Killing spinors that
appear as natural extension of the harmonic spinors associated with the basic
Dirac operator. In the case of foliations with basic-harmonic mean curvature it
turns out that these Killing spinors and twistor spinors coincide with the
standard definition. We obtain the corresponding version of classical results
on closed Riemannian manifold with spin structure, extending some previous
results.


title: On a functional satisfying a weak Palais-Smale condition

abstract:
  In this paper we study a quasilinear elliptic problem whose functional
satisfies a weak version of the well known Palais-Smale condition. An existence
result is proved under general assumptions on the nonlinearities.


title: Effect of the hypomagnetic field on the size of the eye pupil

abstract:
  Previously, we reported that the hypomagnetic field obtained by the 100-fold
deprivation of the geomagnetic field affected human cognitive processes as
estimated in several computer tests. The exposure to the hypomagnetic field
caused a statistically significant increase both in the task processing time
and in the number of errors. The magnitude of this magnetic effect, averaged
over 40 healthy subjects and more than 10^5 separate trials, was about 1.7%. In
the present work, the results of a simultaneous study are described, in which
the right eye of each subject was video recorded, while the subject performed
the tasks. It has appeared that the pupil size grows in the hypomagnetic field.
This effect has been calculated based on the treatment of a large data set of
about 6.10^6 video frames. Averaged all over the frames, the magnetic effect on
the pupil area was about 1.6%, with high statistical confidence. This is the
first laboratory study in which the number of separate trials has been large
enough to obtain rather smooth distribution functions. Thus, the small effect
of the hypomagnetic field on humans has become evident and statistically valid.


title:
Population genetics of neutral mutations in exponentially growing cancer
  cell populations

abstract:
  In order to analyze data from cancer genome sequencing projects, we need to
be able to distinguish causative, or "driver," mutations from "passenger"
mutations that have no selective effect. Toward this end, we prove results
concerning the frequency of neutural mutations in exponentially growing
multitype branching processes that have been widely used in cancer modeling.
Our results yield a simple new population genetics result for the site
frequency spectrum of a sample from an exponentially growing population.


title:
Exploring the adaptive voter model dynamics with a mathematical triple
  jump

abstract:
  Progress in theoretical physics is often made by the investigation of toy
models, the model organisms of physics, which provide benchmarks for new
methodologies. For complex systems, one such model is the adaptive voter model.
Despite its simplicity, the model is hard to analyse. Only inaccurate results
are obtained from well-established approximation schemes that work well on
closely-related models. We use this model to illustrate a new approach that
combines a) the use of a heterogeneous moment expansion to approximate the
network model by an infinite system of ordinary differential equations, b)
generating functions to map the ordinary differential equation system to a
two-dimensional partial differential equation, and c) solution of this partial
differential equation by the tools of PDE-theory. Beyond the adaptive voter
models, the proposed approach establishes a connection between network science
and the theory of partial differential equations and is widely applicable to
the dynamics of networks with discrete node-states.


title: Tidal tails of dwarf galaxies on different orbits around the Milky Way

abstract:
  We present a phenomenological description of the properties of tidal tails
forming around dwarf galaxies orbiting the Milky Way. For this purpose we use
collisionless N-body simulations of dwarfs initially composed of a disk
embedded in an NFW dark matter halo. The dwarfs are placed on seven orbits
around the Milky Way-like host, differing in size and eccentricity, and their
evolution is followed for 10 Gyr. In addition to the well-studied morphological
and dynamical transformation of the dwarf's main body, the tidal stripping
causes them to lose a substantial fraction of mass both in dark matter and
stars which form pronounced tidal tails. We focus on the properties of the
stellar component of the tidal tails thus formed. We first discuss the break
radii in the stellar density profile defining the transition to tidal tails as
the radii where the profile becomes shallower and relate them to the
classically defined tidal radii. We then calculate the relative density and
velocity of the tails at a few break radii as a function of the orbital phase.
Next, we measure the orientation of the tails with respect to an observer
placed at the centre of the Milky Way. The tails are perpendicular to this line
of sight only for a short period of time near the pericentre. For most of the
time the angles between the tails and this line of sight are low, with
orbit-averaged medians below 42 degrees for all, even the almost circular
orbit. The median angle is typically lower while the maximum relative density
higher for more eccentric orbits. The combined effects of relative density and
orientation of the tails suggest that they should be easiest to detect for
dwarf galaxies soon after their pericentre passage.


title: Finite presentability of normal fibre products

abstract:
  We use Bieri-Strebel invariants to determine when a normal fibre product in
the product of two finitely presented groups is finitely presented. We give
conditions that imply and in some cases characterize the existence of such
finitely presented fibre products.


title:
Van der Waals coefficients for systems with ultracold polar alkali-metal
  molecules

abstract:
  A systematic study of the leading isotropic van der Waals coefficients for
the alkali-metal atom + molecule and molecule + molecule systems is presented.
Dipole moments and static and dynamic dipole polarizabilities are calculated
employing high-level quantum chemistry calculations. The dispersion, induction,
and rotational parts of the isotropic van der Waals coefficient are evaluated.
The known van der Waals coefficients are then used to derive characteristics
essential for simple models of the collisions involving the corresponding
ultracold polar molecules.


title:
Effective factors in agile transformation process from change management
  perspective

abstract:
  After introducing agile approach in 2001, several agile methods were founded
over the last decade. Agile values such as customer collaboration, embracing
changes, iteration and frequent delivery, continuous integration, etc. motivate
all software stakeholders to use these methods in their projects. The main
issue is that for using these methods instead of traditional methods in
software development, companies should change their approach from traditional
to agile. This change is a fundamental and critical mutation. Several studies
have been done for investigating of barriers, challenges and issues in agile
movement process and also in how to use agile methods in companies. The main
issue is altering attitude from traditional to agile approach. We believe that
before managing agile transformation process, its related factors should be
studied in deep. This study focuses on different dimensions of changing
approach to agile from change management perspective. These factors are how to
being agile, method selection and awareness of challenges and issues. These
fundamental factors encompass many items for agile movement and adoption
process. However these factors may change in different organization, but they
should be studied in deep before any action plan for designing a change
strategy. The main contribution of this paper is introducing and these factors
and discuss on them deeply.


title:
A Systematic Literature Review on relationship between agile methods and
  Open Source Software Development methodology

abstract:
  Agile software development methods (ASD) and open source software development
methods (OSSD) are two different approaches which were introduced in last
decade and both of them have their fanatical advocators. Yet, it seems that
relation and interface between ASD and OSSD is a fertile area and few rigorous
studies have been done in this matter. Major goal of this study was assessment
of the relation and integration of ASD and OSSD. Analyzing of collected data
shows that ASD and OSSD are able to support each other. Some practices in one
of them are useful in the other. Another finding is that however there are some
case studies using ASD and OSSD simultaneously, but there is not enough
evidence about comprehensive integration of them.


title: Practical Size-based Scheduling for MapReduce Workloads

abstract:
  We present the Hadoop Fair Sojourn Protocol (HFSP) scheduler, which
implements a size-based scheduling discipline for Hadoop. The benefits of
size-based scheduling disciplines are well recognized in a variety of contexts
(computer networks, operating systems, etc...), yet, their practical
implementation for a system such as Hadoop raises a number of important
challenges. With HFSP, which is available as an open-source project, we address
issues related to job size estimation, resource management and study the
effects of a variety of preemption strategies. Although the architecture
underlying HFSP is suitable for any size-based scheduling discipline, in this
work we revisit and extend the Fair Sojourn Protocol, which solves problems
related to job starvation that affect FIFO, Processor Sharing and a range of
size-based disciplines. Our experiments, in which we compare HFSP to standard
Hadoop schedulers, pinpoint at a significant decrease in average job sojourn
times - a metric that accounts for the total time a job spends in the system,
including waiting and serving times - for realistic workloads that we generate
according to production traces available in literature.


title:
Wigner-function formalism applied to semiconductor quantum devices:
  Failure of the conventional boundary-condition scheme

abstract:
  The Wigner-function formalism is a well known approach to model charge
transport in semiconductor nanodevices. Primary goal of the present article is
to point out and explain intrinsic limitations of the conventional
quantum-device modeling based on such Wigner-function paradigm, providing a
definite answer to open questions related to the application of the
conventional spatial boundary-condition scheme to the Wigner transport
equation. Our analysis shows that (i) in the absence of energy dissipation
(coherent limit) the solution of the Wigner equation equipped with given
boundary conditions is not unique, and (ii) when decoherence/dissipation
phenomena are taken into account via a relaxation-time approximation the
solution, although unique, is not necessarily a physical Wigner function.


title: On the existence of orthonormal geodesic bases for Lie algebras

abstract:
  We show that every unimodular Lie algebra, of dimension at most 4, equipped
with an inner product, possesses an orthonormal basis comprised of geodesic
elements. On the other hand, we give an example of a solvable unimodular Lie
algebra of dimension 5 that has no orthonormal geodesic basis, for any inner
product.


title: Adaptive Metric Dimensionality Reduction

abstract:
  We study adaptive data-dependent dimensionality reduction in the context of
supervised learning in general metric spaces. Our main statistical contribution
is a generalization bound for Lipschitz functions in metric spaces that are
doubling, or nearly doubling. On the algorithmic front, we describe an analogue
of PCA for metric spaces: namely an efficient procedure that approximates the
data's intrinsic dimension, which is often much lower than the ambient
dimension. Our approach thus leverages the dual benefits of low dimensionality:
(1) more efficient algorithms, e.g., for proximity search, and (2) more
optimistic generalization bounds.


title:
A Variational Finite Element Model for Large-Eddy Simulations of
  Turbulent Flows

abstract:
  We introduce a new Large Eddy Simulation model in a channel, based on the
projection on finite element spaces as filtering operation in its variational
form, for a given triangulation $\{{\cal T}_h \}_{h>0}$. The eddy viscosity is
expressed in terms of the friction velocity in the boundary layer due to the
wall, and is of a standard sub grid-model form outside the boundary layer. The
mixing length scale is locally equal to the grid size. The computational domain
is the channel without the linear sub-layer of the boundary layer. The no slip
boundary condition (BC) is replaced by a Navier (BC) at the computational wall.
Considering the steady state case, we show that the variational finite element
model we have introduced, has a solution $(\vv_h, p_h)_{h>0}$ that converges to
a solution of the steady state Navier-Stokes Equation with Navier BC.


title: Monopoles On $S^2_F$ From The Fuzzy Conifold

abstract:
  The intersection of the conifold $z_1^2+z_2^2+z_3^2 =0$ and $S^5$ is a
compact 3--dimensional manifold $X^3$. We review the description of $X^3$ as a
principal U(1) bundle over $S^2$ and construct the associated monopole line
bundles. These monopoles can have only even integers as their charge. We also
show the Kaluza--Klein reduction of $X^3$ to $S^2$ provides an easy
construction of these monopoles. Using the analogue of the Jordon-Schwinger
map, our techniques are readily adapted to give the fuzzy version of the
fibration $X^3 \rightarrow S^2$ and the associated line bundles. This is an
alternative new realization of the fuzzy sphere $S^2_F$ and monopoles on it.


title: A Power Mean Inequality involving the complete elliptic integrals

abstract:
  In this paper the authors investigate a power mean inequality for a special
function which is defined by the complete elliptic integrals.


title:
On the convergence to a statistical equilibrium for the wave equations
  coupled to a particle

abstract:
  We consider a linear Hamiltonian system consisting of a classical particle
and a scalar field describing by the wave or Klein-Gordon equations with
variable coefficients. The initial data of the system are supposed to be a
random function which has some mixing properties. We study the distribution
\mu_t of the random solution at time moments t\in\R. The main result is the
convergence of \mu_t to a Gaussian probability measure as t\to\infty. The
mixing properties of the limit measures are studied. The application to the
case of Gibbs initial measures is given.


title: Lock-free Concurrent Data Structures

abstract:
  Concurrent data structures are the data sharing side of parallel programming.
Data structures give the means to the program to store data, but also provide
operations to the program to access and manipulate these data. These operations
are implemented through algorithms that have to be efficient. In the sequential
setting, data structures are crucially important for the performance of the
respective computation. In the parallel programming setting, their importance
becomes more crucial because of the increased use of data and resource sharing
for utilizing parallelism.
  The first and main goal of this chapter is to provide a sufficient background
and intuition to help the interested reader to navigate in the complex research
area of lock-free data structures. The second goal is to offer the programmer
familiarity to the subject that will allow her to use truly concurrent methods.


title: Sparsity and the Bayesian Perspective

abstract:
  Sparsity has been recently introduced in cosmology for weak-lensing and CMB
data analysis for different applications such as denoising, component
separation or inpainting (i.e. filling the missing data or the mask). Although
it gives very nice numerical results, CMB sparse inpainting has been severely
criticized by top researchers in cosmology, based on arguments derived from a
Bayesian perspective. Trying to understand their point of view, we realize that
interpreting a regularization penalty term as a prior in a Bayesian framework
can lead to erroneous conclusions. This paper is by no means against the
Bayesian approach, which has proven to be very useful for many applications,
but warns about a Bayesian-only interpretation in data analysis, which can be
misleading in some cases.


title: Exploration of Recent Advances in the Field of Brain Computer Interfaces

abstract:
  A new approach for implementing number of expressions, emotions and, actions
to operate objects through the thoughts of brain using a Non-Invasive Brain
Computing Interface (BCI) technique has been proposed. In this paper a survey
on brain and its operations are presented. The steps involved in the brain
signal processing are discussed. The current systems are able to present few
expressions and emotions on a single device. The proposed system provides the
extended number of expressions on multiple numbers of objects.


title:
The transition towards immortality: non-linear autocatalytic growth of
  citations to scientific papers

abstract:
  We discuss microscopic mechanisms of complex network growth, with the special
emphasis of how these mechanisms can be evaluated from the measurements on real
networks. As an example we consider the network of citations to scientific
papers. Contrary to common belief that its growth is determined by the linear
preferential attachment, our microscopic measurements show that it is driven by
the nonlinear autocatalytic growth. This invalidates the scale-free hypothesis
for the citation network. The nonlinearity is responsible for a dramatic
dynamical phase transition: while the citation lifetime of majority of papers
is 6-10 years, the highly-cited papers have practically infinite lifetime.


title: Poincar\'e recurrences and Ulam method for the Chirikov standard map

abstract:
  We study numerically the statistics of Poincar\'e recurrences for the
Chirikov standard map and the separatrix map at parameters with a critical
golden invariant curve. The properties of recurrences are analyzed with the
help of a generalized Ulam method. This method allows to construct the
corresponding Ulam matrix whose spectrum and eigenstates are analyzed by the
powerful Arnoldi method. We also develop a new survival Monte Carlo method
which allows us to study recurrences on times changing by ten orders of
magnitude. We show that the recurrences at long times are determined by
trajectory sticking in a vicinity of the critical golden curve and secondary
resonance structures. The values of Poincar\'e exponents of recurrences are
determined for the two maps studied. We also discuss the localization
properties of eigenstates of the Ulam matrix and their relation with the
Poincar\'e recurrences.


title: Deciding Conditional Termination

abstract:
  We address the problem of conditional termination, which is that of defining
the set of initial configurations from which a given program always terminates.
First we define the dual set, of initial configurations from which a
non-terminating execution exists, as the greatest fixpoint of the function that
maps a set of states into its pre-image with respect to the transition
relation. This definition allows to compute the weakest non-termination
precondition if at least one of the following holds: (i) the transition
relation is deterministic, (ii) the descending Kleene sequence
overapproximating the greatest fixpoint converges in finitely many steps, or
(iii) the transition relation is well founded. We show that this is the case
for two classes of relations, namely octagonal and finite monoid affine
relations. Moreover, since the closed forms of these relations can be defined
in Presburger arithmetic, we obtain the decidability of the termination problem
for such loops.


title:
The role of low-mass star clusters in massive star formation. The Orion
  Case

abstract:
  To distinguish between the different theories proposed to explain massive
star formation, it is crucial to establish the distribution, the extinction,
and the density of low-mass stars in massive star-forming regions. We analyze
deep X-ray observations of the Orion massive star-forming region using the
Chandra Orion Ultradeep Project (COUP) catalog. We studied the stellar
distribution as a function of extinction, with cells of 0.03 pc x 0.03 pc, the
typical size of protostellar cores. We derived stellar density maps and
calculated cluster stellar densities. We found that low-mass stars cluster
toward the three massive star-forming regions: the Trapezium Cluster (TC), the
Orion Hot Core (OHC), and OMC1-S. We derived low-mass stellar densities of
10^{5} stars pc^{-3} in the TC and OMC1-S, and of 10^{6} stars pc^{-3} in the
OHC. The close association between the low-mass star clusters with massive star
cradles supports the role of these clusters in the formation of massive stars.
The X-ray observations show for the first time in the TC that low-mass stars
with intermediate extinction are clustered toward the position of the most
massive star, which is surrounded by a ring of non-extincted low-mass stars.
This 'envelope-core' structure is also supported by infrared and optical
observations. Our analysis suggests that at least two basic ingredients are
needed in massive star formation: the presence of dense gas and a cluster of
low-mass stars. The scenario that better explains our findings assumes high
fragmentation in the parental core, accretion at subcore scales that forms a
low-mass stellar cluster, and subsequent competitive accretion. Finally,
although coalescence does not seem a common mechanism for building up massive
stars, we show that a single stellar merger may have occurred in the evolution
of the OHC cluster, favored by the presence of disks, binaries, and gas
accretion.


title: On the equivalence of Euler-Lagrange and Noether equations

abstract:
  We prove that on the condition of non-trivial solutions, the Euler-Lagrange
and Noether equations are equivalent for the variational problem of nonlinear
Poisson equation and a class of more general Lagrangians, including position
independent and of p-Laplacian type. As applications we prove certain
propositions concerning the nonlinear Poisson equation and its generalisations,
the equivalence of admissible and inner variations and discuss the inverse
problem of determining the Lagrangian from conservation or symmetry laws.


title:
Factorization method for nonlinear evolution equations Factorization
  method for nonlinear evolution equations

abstract:
  The traditional method of factorization can be used to obtain only the
particular solutions of the Li\'enard type ordinary differential equations. We
suggest a modification of the approach that can be used to construct general
solutions . We first demonstrate the effectiveness of our method by dealing
with a solvable form of the modified Emden-type equation and subsequently
employ it to obtain the solitary wave solutions of the KdV, mKdV, Rosenau-Hyman
(RH) and NLS equations. The solution of the mKdV equation, via the so-called
Muira transform, leads to a singular solution of the KdV equation in addition
to the well-known soliton solution supported by it. We obtain the solution of
the non-integrable RH equation in terms of the Jacobi function and show that,
although robust, it is structurally different from the KdV soliton. We also
find the soliton solution of the NLS equation that accounts for the evolution
of complex envelopes in an optical medium.


title:
On a problem due to Littlewood concerning polynomials with unimodular
  coefficients

abstract:
  Littlewood raised the question of how slowly ||f_n||_4^4-||f_n||_2^4 (where
||.||_r denotes the L^r norm on the unit circle) can grow for a sequence of
polynomials f_n with unimodular coefficients and increasing degree. The results
of this paper are the following. For g_n(z)=\sum_{k=0}^{n-1}e^{\pi ik^2/n} z^k
the limit of (||g_n||_4^4-||g_n||_2^4)/||g_n||_2^3 is 2/\pi, which resolves a
mystery due to Littlewood. This is however not the best answer to Littlewood's
question: for the polynomials h_n(z)=\sum_{j=0}^{n-1}\sum_{k=0}^{n-1} e^{2\pi
ijk/n} z^{nj+k} the limit of (||h_n||_4^4-||h_n||_2^4)/||h_n||_2^3 is shown to
be 4/\pi^2. No sequence of polynomials with unimodular coefficients is known
that gives a better answer to Littlewood's question. It is an open question as
to whether such a sequence of polynomials exists.


title:
Coherence and sufficient sampling densities for reconstruction in
  compressed sensing

abstract:
  We give a new, very general, formulation of the compressed sensing problem in
terms of coordinate projections of an analytic variety, and derive sufficient
sampling rates for signal reconstruction. Our bounds are linear in the
coherence of the signal space, a geometric parameter independent of the
specific signal and measurement, and logarithmic in the ambient dimension where
the signal is presented. We exemplify our approach by deriving sufficient
sampling densities for low-rank matrix completion and distance matrix
completion which are independent of the true matrix.


title: Luminosity bias: from haloes to galaxies

abstract:
  Large surveys of the local Universe have shown that galaxies with different
intrinsic properties, such as colour, luminosity and morphological type display
a range of clustering amplitudes. Galaxies are therefore not faithful tracers
of the underlying matter distribution. This modulation of galaxy clustering,
called bias, contains information about the physics behind galaxy formation. It
is also a systematic to be overcome before the large-scale structure of the
Universe can be used as a cosmological probe. Two types of approaches have been
developed to model the clustering of galaxies. The first class is empirical and
filters or weights the distribution of dark matter to reproduce the measured
clustering. In the second approach an attempt is made to model the physics
which governs fate of baryons in order to predict the number of galaxies in
dark matter haloes. I will review the development of both approaches and
summarize what we have learnt about galaxy bias.


title:
Parameter dependent optimal thresholds, indifference levels and inverse
  optimal stopping problems

abstract:
  Consider the classic infinite-horizon problem of stopping a one-dimensional
diffusion to optimise between running and terminal rewards and suppose we are
given a parametrised family of such problems. We provide a general theory of
parameter dependence in infinite-horizon stopping problems for which threshold
strategies are optimal. The crux of the approach is a supermodularity condition
which guarantees that the family of problems is indexable by a set valued map
which we call the indifference map. This map is a natural generalisation of the
allocation (Gittins) index, a classical quantity in the theory of dynamic
allocation. Importantly, the notion of indexability leads to a framework for
inverse optimal stopping problems.


title:
Transient growth mechanisms of low Reynolds number flow over a
  low-pressure turbine blade

abstract:
  A direct transient growth analysis for three-dimensional perturbations to
flow past a periodic array of T-106/300 low-pressure turbine fan blades is
presented. The methodology is based on a singular value decomposition of the
flow evolution operator, linearised about a steady or periodic base flow. This
analysis yields the optimal growth modes. Previous work on global mode
stability analysis of this flow geometry showed the flow is asymptotically
stable, indicating a non-modal explanation of transition may be more
appropriate. The present work extends previous investigations into the
transient growth around a steady base flow, to higher Reynolds numbers and
periodic base flows. It is found that the notable transient growth of the
optimal modes suggests a plausible route to transition in comparison to modal
growth for this configuration. The spatial extent and localisation of the
optimal modes is examined and possible physical triggering mechanisms are
discussed. It is found that for longer times and longer spanwise wavelengths, a
separation in the shear layer excites the wake mode. For shorter times and
spanwise wavelengths, smaller growth associated with excitation of the near
wake are observed.


title:
Quasi-Bell states in a strongly coupled qubit-oscillator system and
  their delocalization in the phase space

abstract:
  We study the evolution of bipartite entangled quasi-Bell states in a strongly
coupled qubit-oscillator system in the presence of a static bias, and extend it
to the ultra-strong coupling regime. Using the adiabatic approximation the
reduced density matrix of the qubit is obtained for the strong coupling domain
in closed form that involves linear combinations of the Jacobi theta functions.
The reduced density matrix of the oscillator yields the phase space Husimi
Q-distribution. In the strong coupling regime the $Q$-function evolves to
uniformly separated macroscopically distinct Gaussian peaks representing
`kitten' states at certain specified times that depend on multiple time scales
present in the interacting system. For the ultra-strong coupling realm the
delocalization in the phase space of the oscillator is studied by using the
Wehrl entropy and the complexity of the quantum state. For a small phase space
amplitude the entangled quasi-Bell state develops, during its time evolution,
squeezing property and nonclassicality of the photon statistics which are
measured by the quadrature variance and the Mandel parameter, respectively.


title: Fine structures in the atmosphere above a sunspot umbra

abstract:
  We present simultaneous photospheric and chromospheric observations of the
trailing sunspot in NOAA 10904, obtained with the Swedish Solar Telescope (SST)
La Palma, Canary Islands. Time series of high resolution \ion{Ca}{ii}\,$H$
images show transient jet-like structures in sunspot umbrae are elongated,
which we call umbral microjets. These jets are directed roughly parallel to
nearby penumbral microjets, suggesting that they are aligned with the
background magnetic field. In general, first a bright dot-like structure
appears, from which a jet later emerges, although some jets appear without an
associated chromospheric dot. Bright photospheric umbral dots are associated
with umbral microjets arising in the outer umbra. Nevertheless, a one-to-one
correspondence between jet-like events and underlying umbral dots is not seen.
They are typically less than 1\arcsec ~long and less than 0\farcs3 wide. The
typical lifetime of umbral microjets is around one minute. The brightness of
these structures increases from the center of the umbra towards the
umbra-penumbra boundary along with the brightness of the local background.


title: Bubble concentration on spheres for supercritical elliptic problems

abstract:
  We consider the supercritical Lane-Emden problem $$(P_\eps)\qquad
  -\Delta v= |v|^{p_\eps-1} v \ \hbox{in}\ \mathcal{A} ,\quad u=0\ \hbox{on}\
\partial\mathcal{A} $$
  where $\mathcal A$ is an annulus in $\rr^{2m},$ $m\ge2$ and
$p_\eps={(m+1)+2\over(m+1)-2}-\eps$, $\eps>0.$
  We prove the existence of positive and sign changing solutions of $(P_\eps)$
concentrating and blowing-up, as $\eps\to0$, on $(m-1)-$dimensional spheres.
Using a reduction method (see Ruf-Srikanth (2010) J. Eur. Math. Soc. and
Pacella-Srikanth (2012) arXiv:1210.0782)we transform problem $(P_\eps)$ into a
nonhomogeneous problem in an annulus $\mathcal D\subset \rr^{m+1}$ which can be
solved by a Ljapunov-Schmidt finite dimensional reduction.


title: Morita theory in enriched context

abstract:
  We develop a homotopy theoretical version of classical Morita theory using
the notion of a strong monad. It was Anders Kock who proved that a monad T in a
monoidal category E is strong if and only if T is enriched in E. We prove that
this correspondence between strength and enrichment follows from a
2-isomorphism of 2-categories. Under certain conditions on T, we prove that the
category of T-algebras is Quillen equivalent to the category of modules over
the endomorphism monoid of the T-algebra T(I) freely generated by the unit I of
E. In the special case where E is the category of Gamma-spaces equipped with
Bousfield-Friedlander's stable model structure and T is the strong monad
associated to a well-pointed Gamma-theory, we recover a theorem of Stefan
Schwede, as an instance of a general homotopical Morita theorem.


title: Inertia from an asymmetric Casimir effect

abstract:
  The property of inertia has never been fully explained. A model for inertia
(MiHsC or quantised inertia) has been suggested that assumes that 1) inertia is
due to Unruh radiation and 2) this radiation is subject to a Hubble-scale
Casimir effect. This model has no adjustable parameters and predicts the cosmic
acceleration, and galaxy rotation without dark matter, suggesting that Unruh
radiation indeed causes inertia, but the exact mechanism by which it does this
has not been specified. The mechanism suggested here is that when an object
accelerates, for example to the right, a dynamical (Rindler) event horizon
forms to its left, reducing the Unruh radiation on that side by a Rindler-scale
Casimir effect whereas the radiation on the other side is only slightly reduced
by a Hubble-scale Casimir effect. This produces an imbalance in the radiation
pressure on the object, and a net force that always opposes acceleration, like
inertia. A formula for inertia is derived, and an experimental test is
suggested.


title: Dual view FIDA measurements on MAST

abstract:
  A Fast Ion Deuterium Alpha (FIDA) spectrometer was installed on MAST to
measure radially resolved information about the fast ion density and its
distribution in energy and pitch angle. Toroidally and vertically-directed
collection lenses are employed, to detect both passing and trapped particle
dynamics, and reference views are installed to subtract the background. This
background is found to contain a substantial amount of passive FIDA emission
driven by edge neutrals, and to depend delicately on viewing geometry. Results
are compared with theoretical expectations based on the codes NUBEAM (for fast
ion distributions) and FIDASIM. Calibrating via the measured beam emission
peaks, the toroidal FIDA signal profile agrees with classical simulations in
MHD quiescent discharges where the neutron rate is also classical. Long-lived
modes (LLM) and chirping modes decrease the core FIDA signal significantly, and
the profile can be matched closely to simulations using anomalous diffusive
transport; a spatially uniform diffusion coefficient is sufficient for chirping
modes, while a core localized diffusion is better for a LLM. Analysis of a
discharge with chirping mode activity shows a dramatic drop in the core FIDA
signal and rapid increase in the edge passive signal at the onset of the burst
indicating a very rapid redistribution towards the edge. Vertical viewing
measurements show a discrepancy with simulations at higher Doppler shifts when
the neutron rate is classical, which, combined with the fact that the toroidal
signals agree, means that the difference must be occurring for pitch angles
near the trapped-passing boundary. Further evidence of an anomalous transport
mechanism for these particles is provided by the fact that an increase of beam
power does not increase the higher energy vertical FIDA signals, while the
toroidal signals do increase.


title: "Ping-pong" electron transfer. I. First reflection of the Loschmidt echo

abstract:
  Quantum dynamics of the electron wave function on one-dimensional lattice is
considered. The lattice consists of $N$ equal sites and one impurity site. The
impurity site differs from other sites by the on-site electron energy $E$ and
the hopping integral $C$. The wave function is located on the impurity site at
$t = 0$. The wave packet is formed which travels along the lattice, and
reflects from its end. Reflections happen many times (Loschmidt echo) and this
phenomenon is considered in the second part of the paper. Analytical
expressions for the wave packet front propagation at different values $E$ and
$C$ are derived, and they are in excellent agreement with the numerical
simulation. The obtained results can help in interpretation of recent
experiments on highly efficient charge transport in synthetic olygonucleotides.