title:
Keck Adaptive Optics Observations of the Protostellar Disk around Radio
  Source I in the Orion Kleinmann-Low Nebula

abstract:
  We have made the first detection of a near-infrared counterpart associated
with the disk around Radio Source "I," a massive protostar in the Kleinmann-Low
Nebula in Orion using imaging with laser guide star adaptive optics on the Keck
II telescope. The infrared emission is evident in images acquired using L' (3.8
microns) and Ms (4.7 microns) filters and is not detectable at K' (2.1
microns). The observed morphology strongly suggests that we are seeing some
combination of scattered and thermal light emanating from the disk. The disk is
also manifest in the L'/Ms flux ratio image. We interpret the near-infrared
emission as the illuminated surface of a nearly edge-on disk, oriented so that
only the northern face is visible; the opposite surface remains hidden by the
disk. We do not see infrared radiation associated directly with the star
proposed to be associated with Source "I." The data also suggest that there is
a cavity above and below the disk that is oriented perpendicular to the disk,
and is sculpted by the known, strong outflow from the inner disk of Source I.
We compare our data to models of a protostar with a surrounding disk, envelope,
and wind-blown cavity in order to elucidate the nature of the disk around Radio
Source I.


title:
Interview with Warren Wiscombe on scientific programing and his
  contributions to atmospheric science tool making

abstract:
  On March 11, 2013 I talked with Warren Wiscombe about his contributions to
scientific computer programming, atmospheric science and radiative transfer.
Our conversation is divided into three parts related to light scattering,
radiative transfer and his general thoughts about scientific programming. There
are some reflections on how radiative transfer parameterizations gradually
sneaked in to modern climate and atmospheric Global Circulation Models. Why
some software programs such as light scattering code MIEV and DISORT are very
successful and why some of them fizzle. We talked about the role of tools in
modern science, open source movement, repeatability of scientific results,
computer languages, computer programs as objects of arts, and even if programs
can be revolutionary.


title: On blowup dynamics in the Keller-Segel model of chemotaxis

abstract:
  We investigate the (reduced) Keller-Segel equations modeling chemotaxis of
bio-organisms. We present a formal derivation and partial rigorous results of
the blowup dynamics of solution of these equations describing the chemotactic
aggregation of the organisms. Our results are confirmed by numerical
simulations and the formula we derive coincides with the formula of Herrero and
Vel\'{a}zquez for specially constructed solutions.

categories: nlin.PS math-ph math.AP math.MP physics.bio-ph


title: A Scalable and Nearly Uniform Generator of SAT Witnesses

abstract:
  Functional verification constitutes one of the most challenging tasks in the
development of modern hardware systems, and simulation-based verification
techniques dominate the functional verification landscape. A dominant paradigm
in simulation-based verification is directed random testing, where a model of
the system is simulated with a set of random test stimuli that are uniformly or
near-uniformly distributed over the space of all stimuli satisfying a given set
of constraints. Uniform or near-uniform generation of solutions for large
constraint sets is therefore a problem of theoretical and practical interest.
For Boolean constraints, prior work offered heuristic approaches with no
guarantee of performance, and theoretical approaches with proven guarantees,
but poor performance in practice. We offer here a new approach with theoretical
performance guarantees and demonstrate its practical utility on large
constraint sets.


title:
Operator folding and matrix product states in linearly-coupled bosonic
  arrays

abstract:
  A protocol to obtain the matrix product state representation of a class of
boson states is introduced. The proposal is presented in the context of linear
systems and is tested by performing simulations of a reference model. The
method can be applied regardless of the details of the coupling among modes and
can be used to extract the most significant contribution of the tensorial
representation. Characteristic issues as well as potential variants of the
proposed protocol are discussed.


title:
Clumping and the Interpretation of kpc-Scale Maps of the Interstellar
  Medium: Smooth HI and Clumpy, Variable H2 Surface Density

abstract:
  Many recent models consider the structure of individual interstellar medium
(ISM) clouds as a way to explain observations of large parts of galaxies. To
compare such models to observations, one must understand how to translate
between surface densities observed averaging over large (~kpc) scales and
surface densities on the scale of individual clouds (~pc scale), which are
treated by models. We define a "clumping factor" that captures this translation
as the ratio of the mass-weighted surface density, which is often the quantity
of physical interest, to the area-weighted surface density, which is observed.
We use high spatial resolution (sub-kpc) maps of CO and HI emission from nearby
galaxies to measure the clumping factor of both atomic and molecular gas. The
molecular and atomic ISM exhibit dramatically different degrees of clumping. As
a result, the ratio H2/HI measured at ~kpc resolution cannot be trivially
interpreted as a cloud-scale ratio of surface densities. HI emission appears
very smooth, with a clumping factor of only ~1.3. Based on the scarce and
heterogeneous high resolution data available, CO emission is far more clumped
with a widely variable clumping factor, median ~7 for our heterogeneous data.
Our measurements do not provide evidence for a universal mass-weighted surface
density of molecular gas, but also cannot conclusively rule out such a
scenario. We suggest that a more sophisticated treatment of molecular ISM
structure, one informed by high spatial resolution CO maps, is needed to link
cloud-scale models to kpc-scale observations of galaxies.


title:
Pointwise and grand maximal function characterizations of Besov-type and
  Triebel-Lizorkin-type spaces

abstract:
  In this note, we establish characterizations for the homogeneous Besov-type
spaces $\dot{B}^{s,\tau}_{p,q}(\mathbb{R}^n)$ and Triebel-Lizorkin-type spaces
$\dot{F}^{s,\tau}_{p,q}(\mathbb{R}^n)$, introduced by Yang and Yuan, through
fractional Haj\l asz-type gradients for suitable values of the parameters $p$,
$q$ and $\tau$ when $0 < s < 1$, and through grand Littlewood-Paley-type
maximal functions for all admissible values of the parameters. These
characterizations extend the characterizations obtained by Koskela, Yang and
Zhou for the standard homogeneous Besov and Triebel-Lizorkin spaces.


title:
A remark on decay rates of solutions for a system of quadratic nonlinear
  Schr\"odinger equations in 2D

abstract:
  We consider the initial value problem for a three-component system of
quadratic nonlinear Schr\"odinger equations with mass resonance in two space
dimensions. Under a suitable condition on the coefficients of the nonlinearity,
we will show that the solution decays strictly faster than $O(t^{-1})$ as $t
\to +\infty$ in $L^{\infty}$ by providing with an enhanced decay estimate of
order $O((t \log t)^{-1})$. Differently from the previous works, our approach
does not rely on the explicit form of the asymptotic profile of the solution at
all.


title:
More on the relation between the two physically inequivalent
  decompositions of the nucleon spin

abstract:
  The recent controversy on the nucleon spin decomposition problem is
critically overviewed. We argue that there exist two and only two physically
inequivalent gauge-invariant decompositions of the longitudinal nucleon spin,
contrary to the rapidly spreading view in the QCD spin physics community that
there are infinitely many decompositions of the nucleon spin.


title: Online Power-Managing Strategy with Hard Real-Time Guarantees

abstract:
  We consider the problem of online dynamic power management that provides hard
real-time guarantees. In this problem, each of the given jobs is associated
with an arrival time, a deadline, and an execution time, and the objective is
to decide a schedule of the jobs as well as a sequence of state transitions on
the processors so as to minimize the total energy consumption.
  In this paper, we examine the problem complexity and provide online
strategies to achieve energy-efficiency. First, we show that the competitive
factor of any online algorithm for this problem is at least 2.06. Then we
present an online algorithm which gives a 4-competitive schedule. When the
execution times of the jobs are unit, we show that the competitive factor
improves to 3.59. At the end, the algorithm is generalized to allow a trade-off
between the number of processors we use and the energy-efficiency of the
resulting schedule.


title: Decoherence and Copenhagen Interpretation : A Scenario

abstract:
  In this paper we give a reasonable explanation (not proof) to the Copenhagen
interpretation of Quantum Mechanics from the view point of decoherence theory.
  Mathematical physicists with strong mission must prove {\bf the Copenhagen
interpretation} at all costs.


title:
Bipartite bound entanglement in continuous variables through
  deGaussification

abstract:
  We introduce a class of bipartite entangled continuous variable states that
are positive under partial transposition operation, i.e., PPT bound entangled.
These states are based on realistic preparation procedures in optical systems,
being thus a feasible option to generate and observe genuinely bipartite bound
entanglement in high precision experiments. One fundamental step in our scheme
is to perform a non-Gaussian operation over a single-mode Gaussian state; this
deGaussification procedure is achieved through a modified single-photon
addition, which is a procedure that has currently being investigated in diverse
optical setups. Although dependent on a single-photon detection in a idler
channel, the preparation can be made unconditional after a calibration of the
apparatus. The detection and proof of bound entanglement is made by means of
the Range Criterion, theory of Hankel operators and Gerschgorin Disk s
perturbation theorems.


title: A Low Temperature Expansion for Matrix Quantum Mechanics

abstract:
  We analyze solutions to loop-truncated Schwinger-Dyson equations in massless
N=2 and N=4 Wess-Zumino matrix quantum mechanics at finite temperature, where
conventional perturbation theory breaks down due to IR divergences. We find a
rather intricate low temperature expansion that involves fractional power
scaling in the temperature, based on a consistent "soft collinear"
approximation. We conjecture that at least in the N=4 matrix quantum mechanics,
such scaling behavior holds to all perturbative orders in the 1/N expansion. We
discuss some preliminary results in analyzing the gauged supersymmetric quantum
mechanics using Schwinger-Dyson equations, and comment on the connection to
metastable microstates of black holes in the holographic dual of BFSS matrix
quantum mechanics.


title:
One-dimensional electronic solitons of graphene in an electromagnetic
  field

abstract:
  Electronic energy-eigen-states of graphene in an orthogonal electromagnetic
field with relative magnitude beta=E/vf*B>=1 or in a pure electric field are
obtained by a differential-equation method. Gaussian wave packets of
probability density are constructed and found to transform form two-dimensional
solitons into one-dimension ones at beta=1, when beta increases form beta<1
into beta>1. The maximum number of one-dimensional solitons of a finite
graphene in the field is used to determine the electronic energy levels. These
energy levels and the velocity of solitons lead to nonlinear dependence of the
current on the Hall voltage for the field with beta>1 and nonlinear
current-voltage curves for the pure electric field including the step-like ones
at low temperatures, according to the ballistic transport of solitons.


title: Scalar-field theory of dark matter

abstract:
  We develop a theory of dark matter based on a previously proposed picture, in
which a complex vacuum scalar field makes the universe a superfluid, with the
energy density of the superfluid giving rise to dark energy, and variations
from vacuum density giving rise to dark matter. We formulate a nonlinear
Klein-Gordon equation to describe the superfluid, treating galaxies as external
sources. We study the response of the superfluid to the galaxies, in
particular, the emergence of the dark-matter galactic halo, contortions during
galaxy collisions, and the creation of vortices due to galactic rotation.


title:
The Structure of Global Attractors for Dissipative Zakharov Systems with
  Forcing on the Torus

abstract:
  The Zakharov system was originally proposed to study the propagation of
Langmuir waves in an ionized plasma. In this paper, motivated by earlier work
of the first and third authors, we numerically and analytically investigate the
dynamics of the dissipative Zakharov system on the torus in 1 dimension. We
find an interesting family of stable periodic orbits and fixed points, and
explore bifurcations of those points as we take weaker and weaker dissipation.


title:
Magnetic monopoles and synthetic spin-orbit coupling in Rydberg
  macrodimers

abstract:
  We show that sizeable Abelian and non-Abelian gauge fields arise in the
relative motion of two dipole-dipole interacting Rydberg atoms. Our system
exhibits two magnetic monopoles for adiabatic motion in one internal two-atom
state. These monopoles occur at a characteristic distance between the atoms
that is of the order of one micron. The deflection of the relative motion due
to the Lorentz force gives rise to a clear signature of the effective magnetic
field. In addition, we consider non-adiabatic transitions between two
near-degenerate internal states and show that the associated gauge fields are
non-Abelian. We present quantum mechanical calculations of this synthetic
spin-orbit coupling and show that it realizes a velocity-dependent
beamsplitter.


title: A New Distribution-Random Limit Normal Distribution

abstract:
  This paper introduces a new distribution to improve tail risk modeling. Based
on the classical normal distribution, we define a new distribution by a series
of heat equations. Then, we use market data to verify our model.


title: The Numerical Properties of G-heat equation and Related Application

abstract:
  In this paper, we consider the numerical convergence of G-heat equation which
was first introduced by Peng. The G-heat equation extends the classical heat
equation with uncertain volatility. For G-heat equation is nonlinear partial
differential equation(PDE), we prove that the Newton iteration is convergence
and the fully implicit discretization is monotone and stable. Then, we have the
fully implicit discretization convergence to the viscosity solution of a G-heat
equation.


title:
On estimation of mean squared errors of benchmarked empirical Bayes
  estimators

abstract:
  We consider benchmarked empirical Bayes (EB) estimators under the basic
area-level model of Fay and Herriot while requiring the standard benchmarking
constraint. In this paper we determine the excess mean squared error (MSE) from
constraining the estimates through benchmarking. We show that the increase due
to benchmarking is O(m^{-1}), where m is the number of small areas.
Furthermore, we find an asymptotically unbiased estimator of this MSE and
compare it to the second-order approximation of the MSE of the EB estimator or,
equivalently, of the MSE of the empirical best linear unbiased predictor
(EBLUP), that was derived by Prasad and Rao (1990). Morever, using methods
similar to those of Butar and Lahiri (2003), we compute a parametric bootstrap
estimator of the MSE of the benchmarked EB estimator under the Fay-Herriot
model and compare it to the MSE of the benchmarked EB estimator found by a
second-order approximation. Finally, we illustrate our methods using SAIPE data
from the U.S. Census Bureau, and in a simulation study.


title: Allometric Exponent and Randomness

abstract:
  An allometric height-mass exponent $\gamma$ gives an approximative power-law
relation $< M> \propto H^\gamma$ between the average mass $< M>$ and the height
$H$, for a sample of individuals. The individuals in the present study are
humans but could be any biological organism. The sampling can be for a specific
age of the individuals or for an age-interval. The body-mass index (BMI) is
often used for practical purposes when characterizing humans and it is based on
the allometric exponent $\gamma=2$. It is here shown that the actual value of
$\gamma$ is to large extent determined by the degree of correlation between
mass and height within the sample studied: no correlation between mass and
height means $\gamma=0$, whereas if there was a precise relation between mass
and height such that all individuals had the same shape and density then
$\gamma=3$. The connection is demonstrated by showing that the value of
$\gamma$ can be obtained directly from three numbers characterizing the spreads
of the relevant random Gaussian statistical distributions: the spread of the
height and mass distributions together with the spread of the mass distribution
for the average height. Possible implications for allometric relations in
general are discussed.


title: Hall-Littlewood polynomials and characters of affine Lie algebras

abstract:
  The Weyl-Kac character formula gives a beautiful closed-form expression for
the characters of integrable highest-weight modules of Kac-Moody algebras. It
is not, however, a formula that is combinatorial in nature, obscuring
positivity. In this paper we show that the theory of Hall-Littlewood
polynomials may be employed to prove Littlewood-type combinatorial formulas for
the characters of certain highest weight modules of the affine Lie algebras
C_n^{(1)}, A_{2n}^{(2)} and D_{n+1}^{(2)}. Through specialisation this yields
generalisations for B_n^{(1)}, C_n^{(1)}, A_{2n-1}^{(2)}, A_{2n}^{(2)} and
D_{n+1}^{(2)} of Macdonald's identities for powers of the Dedekind
eta-function. These generalised eta-function identities include the
Rogers-Ramanujan, Andrews-Gordon and G\"ollnitz-Gordon q-series as special,
low-rank cases.


title: Neutrino Mixing and Geometric CP Violation with Delta(27) Symmetry

abstract:
  Predictive spontaneous CP violation is possible if it is obtained
geometrically through a non-Abelian discrete symmetry. I propose such a model
of neutrino mass and mixing based on Delta(27).


title: Complex competitive systems and competitive thermodynamics

abstract:
  This publication reviews the framework of abstract competition, which is
aimed at studying complex systems with competition in their generic form.
Although the concept of abstract competition has been derived from a specific
field - modelling of mixing in turbulent reacting flows - this concept is,
generally, not attached to a specific phenomenon or application. Two classes of
competition rules, transitive and intransitive, need to be distinguished.
Transitive competitions are shown to be consistent (at least qualitatively)
with thermodynamic principles, which allows for introduction of special
competitive thermodynamics. Competitive systems can thus be characterised by
thermodynamic quantities (such as competitive entropy and competitive
potential), which determine that the predominant direction of evolution of the
system is directed towards higher competitiveness. There is, however, an
important difference: while conventional thermodynamics is constrained by its
zeroth law and is fundamentally transitive, the transitivity of competitive
thermodynamics depends on the transitivity of the competition rules. The
analogy with conventional thermodynamics weakens as competitive systems become
more intransitive, while strongly intransitive competitions can display types
of behaviour associated with complexity: competitive cooperation and leaping
cycles. Results of simulations demonstrating complex behaviour in abstract
competitions are presented in the electronic supplementary material (ESM).


title:
A classification of radial and totally geodesic ends of properly convex
  real projective orbifolds

abstract:
  Real projective structures on $n$-orbifolds are useful in understanding the
space of representations of discrete groups into $SL(n+1, \mathbb{R})$ or
$PGL(n+1, \mathbb{R})$. A recent work shows that many hyperbolic manifolds
deform to manifolds with such structures not projectively equivalent to the
original ones. The purpose of this paper is to understand the structures of
ends of real projective $n$-dimensional orbifolds. In particular, these have
the radial or totally geodesic ends. Hyperbolic manifolds with cusps and
hyper-ideal ends are examples. For this, we will study the natural conditions
on eigenvalues of holonomy representations of ends when these ends are
manageably understandable. The main techniques are the theory of Fried and
Goldman on affine manifolds, a generalization of the work of Goldman, Labourie,
and Margulis on flat Lorentzian $3$-manifolds and the work on Riemannian
foliations by Molino, Carri\`ere, and so on. We will show that only the radial
or totally geodesic ends of lens type or horospherical ends exist for strongly
irreducible properly convex real projective orbifolds under the suitable
conditions.


title: On Some Integrals Over the Product of Three Legendre Functions

abstract:
  The definite integrals $ \int_{-1}^1(1-x^2)^{(\nu-1)/2}[P_\nu(x)]^3\D x$, $
\int_{-1}^1(1-x^2)^{(\nu-1)/2}[P_\nu(x)]^2P_{\nu}(-x)\D x$,
$\int_{-1}^1x(1-x^2)^{(\nu-1)/2}[P_{\nu+1}(x)]^3\D x $ and
$\int_{-1}^1x(1-x^2)^{(\nu-1)/2}[P_{\nu+1}(x)]^2P_{\nu+1}(-x)\D x $ are
evaluated in closed form, where $P_\nu$ is the Legendre function of degree
$\nu$, and $ \R\nu>-1$. Special cases of these formulae are related to certain
integrals over elliptic integrals that have arithmetic interest.


title: On quasi-periodic solutions of the discrete Chen-Lee-Liu hierarchy

abstract:
  Resorting to the Lax matrix and elliptic variables, the discrete Chen-Lee-Liu
hierarchy is decomposed into solvable ordinary differential equations. Based on
the theory of algebraic curve, the continuous flow and discrete flow related to
the discrete Chen-Lee-Liu hierarchy are straightened under the Abel-Jacobi
coordinates. The meromorphic function $\phi$, the Baker-Akhiezer vector
$\bar\psi $ and the hyperelliptic curve $\mathcal{K}_N$ are introduced, by
which quasi-periodic solutions of the discrete Chen-Lee-Liu hierarchy are
constructed according to the asymptotic properties and the algebro-geometric
characters of $\phi,\ \bar\psi $ and $\mathcal{K}_N$.


title: Simulating DNLS models

abstract:
  We present different techniques to numerically solve the equations of motion
for the widely studied Discrete Nonlinear Schroedinger equation (DNLS). Being a
Hamiltonian system, the DNLS requires symplectic routines for an efficient
numerical treatment. Here, we introduce different such schemes in detail and
compare their performance and accuracy by extensive numerical simulations.


title:
City versus wetland: Predicting urban growth in the Vecht area with a
  cellular automaton model

abstract:
  There are many studies dealing with the protection or restoration of wetlands
and the sustainable economic growth of cities as separate subjects. This study
investigates the conflict between the two in an area where city growth is
threatening a protected wetland area. We develop a stochastic cellular
automaton model for urban growth and apply it to the Vecht area surrounding the
city of Hilversum in the Netherlands, using topographic maps covering the past
150 years. We investigate the dependence of the urban growth pattern on the
values associated with the protected wetland and other types of landscape
surrounding the city. The conflict between city growth and wetland protection
is projected to occur before 2035, assuming full protection of the wetland. Our
results also show that a milder protection policy, allowing some of the wetland
to be sacrificed, could be beneficial for maintaining other valuable
landscapes. This insight would be difficult to achieve by other analytical
means. We conclude that even slight changes in usage priorities of landscapes
can significantly affect the landscape distribution in near future. Our results
also point to the importance of a protection policy to take the value of
surrounding landscapes and the dynamic nature of urban areas into account.


title:
Effect of magnetic field on the superconducting phase in the
  electron-doped metallic double-chain compound
  Pr$_{2}$Ba$_{4}$Cu$_{7}$O$_{15-\delta}$

abstract:
  We report the magnetotransport and $dc$ magnetic susceptibility of the
polycrystalline samples of Pr$_{2}$Ba$_{4}$Cu$_{7}$O$_{15-\delta}$, to examine
the effect of magnetic field on the superconducting phase of the metallic CuO
double chain. The resistive critical magnetic field is estimated to be about 21
T at low temperatures from the resistive transition data. On the other hand,
the corresponding critical field determined from the magnetization measurements
gives rise to a very low value of $\sim 0.3$T at 2 K. These discrepancies in
the magnetic response between the resistivity and magnetization data are caused
by disappearance of the magnetically shielding effect even in relatively lower
fields. In spite of the observation of the resistive drop associated with the
superconducting transport currents, the suppression of the diamagnetic signal
is probably related to the superconductivity of quasi one-dimensional CuO
double-chain. The behavior of Seebeck coefficient in the superconducting
Pr$_{2}$Ba$_{4}$Cu$_{7}$O$_{15-\delta}$ is discussed on the basis of the double
chain model from the density functional band calculation.


title: Pb0.95La0.05Zr0.54Ti0.46O3 Thin Films For Photovoltaic Applications

abstract:
  Ferroelectrics have shown potential as a promising alternative material for
future photovoltaic applications. Observance of high open circuit voltages in
ferroelectric thin films, have generated considerable interest in the field of
ferroelectric photovoltaic in recent years. The field of ferroelectric
photovoltaic is evolving and not yet completely understood compared to the
semiconductor based photovoltaic technology. This dissertation investigates
photovoltaic characteristics of ferroelectric films in an attempt to further
the understanding of ferroelectric photovoltaic.
  This dissertation presents photovoltaic properties of ferroelectric
Pb0.95La0.05Zr0.54Ti0.46O3 thin films. The films were fabricated by solution
based method and spin coating technique. The post annealing process on these
films was optimized to achieve the desired ferroelectric and dielectric
properties. A measurement setup was established to study the PV characteristic
of the devices. Dependence of current-voltage (I-V) behavior of the cells on
parameters such as electrical poling, annealing temperature, nature of top
electrodes, and intensity of illumination, were investigated. The photovoltaic
response was shown to improve by using electrodes with low work functions. An
electric circuit model was developed to simulate the behavior of a single
ferroelectric photovoltaic cell and the dependence of open circuit voltage
(Voc) and short circuit current (Isc) on light intensity.


title: On projectively flat Kropina metrics

abstract:
  In this paper, a characteristic condition of the projectively flat Kropina
metric is given. By it, we prove that a Kropina metric $F=\alpha^2/\beta$ with
constant curvature $K$ and $\|\beta\|_{\alpha}=1$ is projectively flat if and
only if $F$ is locally Minkowskian.


title:
Correlated Electronic Structures and the Phase Diagram of
  Hydrocarbon-based Superconductors

abstract:
  We have investigated correlated electronic structures and the phase diagram
of electron-doped hydrocarbon molecular solids, based on the dynamical
mean-field theory. We have found that the ground state of hydrocarbon-based
superconductors such as electron-doped picene and coronene is a multi-band
Fermi liquid, while that of non-superconducting electron-doped pentacene is a
single-band Fermi liquid in the proximity of the metal-insulator transition.
The size of the molecular orbital energy level splitting plays a key role in
producing the superconductivity of electron-doped hydrocarbon solids. The
multi-band nature of hydrocarbon solids would boost the superconductivity
through the enhanced density of states at the Fermi level.


title:
Some examples of dynamically defined ambient homogeneous wild knots in
  higher dimensions

abstract:
  In this paper we consider the Kleinian groups acting conformally on the
sphere $\mathbb{S}^{n+2}$ $(1\leq{n}\leq5)$ which have as limit sets wild
spheres $K^n$ which were constructed in \cite{BHV} and prove that $K^n$ is
ambient homogeneous. In other words, given two points $p,\,\,q\in{K}$ there
exists a homeomorphism $\psi:\mathbb{S}^{n+2}\rightarrow\mathbb{S}^{n+2} $ such
that $\psi(K)=K$ and $\psi(p)=q$.


title:
Fermi level density of states modulation without charge transfer in
  nickelate superlattices

abstract:
  By using first-principles density functional theory calculations for
(LaNiO3)m/(SrTiO3)n superlattices, we report a systematic way of electronic
response to the interface geometry. It is found that Fermi level density of
states of metallic nickelate layers is significantly reduced without charge
transfer in the vicinity of interface to the insulating SrTiO3. This type of
electronic state redistribution is clearly distinctive from other interface
phenomena such as charge and orbital reconstruction. Our result sheds new light
towards understanding the nickelates and other transitionmetal oxide
heterostructures.


title:
Solving Local Equivalence Problems with the Equivariant Moving Frame
  Method

abstract:
  Given a Lie pseudo-group action, an equivariant moving frame exists in the
neighborhood of a submanifold jet provided the action is free and regular. For
local equivalence problems the freeness requirement cannot always be satisfied
and in this paper we show that, with the appropriate modifications and
assumptions, the equivariant moving frame constructions extend to submanifold
jets where the pseudo-group does not act freely at any order. Once this is
done, we review the solution to the local equivalence problem of submanifolds
within the equivariant moving frame framework. This offers an alternative
approach to Cartan's equivalence method based on the theory of G-structures.


title:
Large, Homogeneous, and Isotropic Critical Current Density in
  Oxygen-Annealed Fe1+yTe0.6Se0.4 Single Crystal

abstract:
  We reported a controllable way of removing excess Fe in Fe1+yTe0.6Se0.4 by
annealing in a fixed amount of O2. Compared with the weak superconductivity
induced by dilute acids, O2 annealing can successfully induce bulk
superconductivity. Proper O2 annealing changes the temperature dependence of
resistivity at low temperatures from semiconducting to metallic, which comes
from the deintercalation of excess Fe. Critical current densities with field
along the c-axis and ab-plane are found almost isotropic with large values of
3*10^5 A/cm2 and 2.5*10^5 A/cm2 at 2 K. Furthermore, magneto-optical images
reveal isotropic current flow within the ab-plane.


title: Magnetic fields in cometary globules - IV. LBN 437

abstract:
  We present results of our $R-$band polarimetry of a cometary globule, LBN 437
(Gal96-15, $\ell$ $=$ 96$\degree$, \textit{b} $=-15\degree$), to study magnetic
field geometry of the cloud. We estimated a distance of $360\pm65$ pc to LBN
437 (also one additional cloud, CB 238) using near-IR photometric method.
Foreground contribution to the observed polarisation values was subtracted by
making polarimetric observations of stars that are located in the direction of
the cloud and with known distances from the Hipparcos parallax measurements.
The magnetic field geometry of LBN 437 is found to follow the curved shape of
the globule head. This could be due to the drag that the magnetic field lines
could have experienced because of the ionisation radiation from the same
exciting source that caused the cometary shape of the cloud. The orientation of
the outflow from the Herbig A4e star, LkH$\alpha$ 233 (or V375 Lac), located at
the head of LBN 437, is found to be parallel to both the initial (prior to the
ionising source was turned on) ambient magnetic field (inferred from a star HD
214243 located just in front of the cloud) and the Galactic plane.


title:
Anisotropic Magneto Resistance and Planar Hall Effect at the
  LaAlO$_3$/SrTiO$_3$ Heterointerfaces: Effect of Carrier Confinement on
  Magnetic Interactions

abstract:
  The confinement of the two dimensional electron gas (2DEG), preferential
occupancy of the Ti 3d orbital and strong spin-orbit coupling at the
LaAlO$_3$/SrTiO$_3$ interface play a significant role in its emerging
properties. Here we report a fourfold oscillation in the anisotropic magneto
resistance (AMR) and the observation of planar Hall effect (PHE) at the
LaAlO$_3$/SrTiO$_3$ heterointerface. We evaluate the carrier confinement
effects on the AMR and find that the fourfold oscillation appears only for the
case of 2DEG system while it is twofold for the 3D system. As the fourfold
oscillation fits well to the phenomenological model for a cubic symmetry
system, we attribute this oscillation to the anisotropy in the magnetic
scattering arising from the interaction of electrons with the localized
magnetic moments coupled to the crystal symmetry. The AMR behavior is further
found to be sensitive to applied gate electric field, emphasizing the
significance of spin-orbit coupling at the interface. These confinement effects
suggest that the magnetic interactions are predominant at the interface, and
the gate electric field modulation of AMR suggest the possible gate tunable
magnetic interactions in these systems. The observed large PHE further
indicates that the in plane nature of magnetic ordering arises from the
in-plane Ti 3dxy orbitals.


title: The Structure of HE 1104-1805 from Infrared to X-Ray

abstract:
  The gravitationally lensed quasar HE 1104-1805 has been observed at a variety
of wavelengths ranging from the mid-infrared to X-ray for nearly 20 years. We
combine flux ratios from the literature, including recent Chandra data, with
new observations from the SMARTS telescope and HST, and use them to investigate
the spatial structure of the central regions using a Bayesian Monte Carlo
analysis of the microlensing variability. The wide wavelength coverage allows
us to constrain not only the accretion disk half-light radius r_1/2, but the
power-law slope \xi\ of the size-wavelength relation r_1/2 ~ \lambda^\xi. With
a logarithmic prior on the source size, the (observed-frame) R-band half-light
radius log(r_1/2/cm) is 16.0+0.3-0.4, and the slope \xi\ is 1.0+0.30-0.56. We
put upper limits on the source size in soft (0.4-1.2 keV) and hard (1.2-8 keV)
X-ray bands, finding 95% upper limits on log (r_1/2/cm) of 15.33 in both bands.
A linear prior yields somewhat larger sizes, particularly in the X-ray bands.
For comparison, the gravitational radius, using a black hole mass estimated
using the H\beta\ line, is log(r_g/cm) = 13.94. We find that the accretion disk
is probably close to face-on, with cos i = 1.0 being four times more likely
than cos i = 0.5. We also find probability distributions for the mean mass of
the stars in the foreground lensing galaxy, the direction of the transverse
peculiar velocity of the lens, and the position angle of the projected
accretion disk's major axis (if not face-on).


title:
Local electromagnetic properties of magnetic pnictides: A comparative
  study probed by NMR measurement

abstract:
  75As and 31P NMR studies are performed in PrCoAsO and NdCoPO respectively.
The Knight shift data in PrCoAsO indicate the presence of an antiferromagnetic
interaction between the 4f moments along the c axis in the ferromagnetic state
of Co 3d moments. We propose a possible spin structure in this system. The 75As
quadrupolar coupling constant, $\nu_Q$ increases continuously with the decrease
of temperature and is found to vary linearly with the intrinsic spin
susceptibility, Kiso. This indicates a possibility of the presence of a
coupling between charge density and spin density fluctuations. Further, 31P NMR
Knight shift and spin lattice relaxation rate (1/T1) in the paramagnetic state
of NdCoPO indicate that the differences between LaCoPO and NdCoPO with SmCoPO
are due to the decrement of inter layer separation and not due to the moments
of 4f electrons. Nuclear spin lattice relaxation time (T1) in NdCoPO shows weak
anisotropy at 300 K. Using self consistent renormalization (SCR)theory of
itinerant ferromagnet, it is shown that in the ab plane, the spin fluctuations
are three dimensional ferromagnetic in nature. From SCR theory the important
spin fluctuation parameters ($T_0$, $T_A$, $\bar{F}_1$) are evaluated. The
similarities and dissimilarities of the NMR results in As and P based systems,
with different rare earths have also been discussed.


title: On the boundedness of generalized Ces\`aro operators on Sobolev spaces

abstract:
  For $\beta>0$ and $p\ge 1$, the generalized Ces\`aro operator $$
\mathcal{C}_\beta f(t):=\frac{\beta}{t^\beta}\int_0^t (t-s)^{\beta-1}f(s)ds $$
and its companion operator $\mathcal{C}_\beta^*$ defined on Sobolev spaces
$\mathcal{T}_p^{(\alpha)}(t^\alpha)$ and $\mathcal{T}_p^{(\alpha)}(|
t|^\alpha)$ (where $\alpha\ge 0$ is the fractional order of derivation and are
embedded in $L^p(\RR^+)$ and $L^p(\RR)$ respectively) are studied. We prove
that if $p>1$, then $\mathcal{C}_\beta$ and $\mathcal{C}_\beta^*$ are bounded
operators and commute on $\mathcal{T}_p^{(\alpha)}(t^\alpha)$ and
$\mathcal{T}_p^{(\alpha)}(| t|^\alpha)$. We show explicitly the spectra $\sigma
(\mathcal{C}_\beta)$ and $\sigma (\mathcal{C}_\beta^*)$ and its operator norms
(which depend on $p$). For $1< p\le 2$, we prove that $ \hat{{\mathcal
C}_\beta(f)}={\mathcal C}_\beta^*(\hat{f})$ and $\hat{{\mathcal
C}_\beta^*(f)}={\mathcal C}_\beta(\hat{f})$ where $\hat{f}$ is the Fourier
transform of a function $f\in L^p(\RR)$.


title: Phonon decay in silicon nanocrystals

abstract:
  The decay of the optical phonon into the two phonons of smaller energy is
calculated for Si nanocrystals. The rate of the process is in the range of 1 to
10 ps. Such anharmonic phonon decay may control the energy relaxation rate of
excited carriers in Si/SiO$_2$ nanocrystals. Relevance of the phonon decay to
the experimentally observed hot carrier photoluminescence is discussed.


title: The speed of interfacial waves polarized in a symmetry plane

abstract:
  The surface-impedance matrix method is used to study interfacial waves
polarized in a plane of symmetry of anisotropic elastic materials. Although the
corresponding Stroh polynomial is a quartic, it turns out to be analytically
solvable in quite a simple manner. A specific application of the result
concerns the calculation of the speed of a Stoneley wave, polarized in the
common symmetry plane of two rigidly bonded anisotropic solids. The
corresponding algorithm is robust, easy to implement, and gives directly the
speed (when the wave exists) for any orientation of the interface plane, normal
to the common symmetry plane. Through the examples of the couples
(Aluminum)-(Tungsten) and (Carbon/epoxy)-(Douglas pine), some general features
of a Stoneley wave speed are verified: the wave does not always exist; it is
faster than the slowest Rayleigh wave associated with the separated
half-spaces.


title:
Mathematical modeling of thermal stabilization of vertical wells on high
  performance computing systems

abstract:
  Temperature stabilization of oil and gas wells is used to ensure stability
and prevent deformation of a subgrade estuary zone. In this work, we consider
the numerical simulation of thermal stabilization using vertical seasonal
freezing columns.
  A mathematical model of such problems is described by a time-dependent
temperature equation with phase transitions from water to ice. The resulting
equation is a standard nonlinear parabolic equation.
  Numerical implementation is based on the finite element method using the
package Fenics. After standard purely implicit approximation in time and simple
linearization, we obtain a system of linear algebraic equations. Because the
size of freezing columns are substantially less than the size of the modeled
area, we obtain mesh refinement near columns. Due to this, we get a large
system of equations which are solved using high performance computing systems.


title:
Geometrical characterization of semilinear isomorphisms of vector spaces
  and semilinear homeomorphisms of normed spaces

abstract:
  Let $V$ and $V'$ be vector spaces over division rings (possible
infinite-dimensional) and let ${\mathcal P}(V)$ and ${\mathcal P}(V')$ be the
associated projective spaces. We say that $f:{\mathcal P}(V)\to {\mathcal
P}(V')$ is a PGL-{\it mapping} if for every $h\in {\rm PGL}(V)$ there exists
$h'\in {\rm PGL}(V')$ such that $fh=h'f$. We show that for every PGL-bijection
the inverse mapping is a semicollineation. Also, we obtain an analogue of this
result for the projective spaces associated to normed spaces.


title:
Interference-Aware Resource Control in Multi-Antenna Cognitive Ad Hoc
  Networks with Heterogeneous Delay Constraints

abstract:
  In this work, we consider a multi-antenna cognitive ad hoc network (CAHNet)
with heterogeneous delay requirements. To fulfill the interference and delay
constraints simultaneously, we propose to perform adaptive zero-forcing
beamforming (ZFBF) at cognitive transmitters according to interference channel
state information (CSI). To assist the CAHNet to obtain the interference CSI,
we use a win-win inter-network cooperation strategy, namely quantized
interference CSI feedback from the primary network to CAHNet through a feedback
link, under the condition that the CAHNet pays a proper price for it.
Considering the scarcity of feedback and power resources, we focus on the
minimization of the overall resource cost subject to both interference and
delay constraints. To solve the problem, we derive a joint feedback and power
control algorithm amongst multiple links of CAHNet. Finally, simulation results
validate the effectiveness of the proposed algorithm.


abstract:
  Pattern-Based Constraint Satisfaction and Logic Puzzles develops a pure
logic, pattern-based perspective of solving the finite Constraint Satisfaction
Problem (CSP), with emphasis on finding the "simplest" solution. Different ways
of reasoning with the constraints are formalised by various families of
"resolution rules", each of them carrying its own notion of simplicity. A large
part of the book illustrates the power of the approach by applying it to
various popular logic puzzles. It provides a unified view of how to model and
solve them, even though they involve very different types of constraints:
obvious symmetric ones in Sudoku, non-symmetric but transitive ones
(inequalities) in Futoshiki, topological and geometric ones in Map colouring,
Numbrix and Hidato, and even much more complex non-binary arithmetic ones in
Kakuro (or Cross Sums). It also shows that the most familiar techniques for
these puzzles can indeed be understood as mere application-specific
presentations of the general rules. Sudoku is used as the main example
throughout the book, making it also an advanced level sequel to "The Hidden
Logic of Sudoku" (another book by the same author), with: many examples of
relationships among different rules and of exceptional situations; comparisons
of the resolution potential of various families of rules; detailed statistics
of puzzles hardness; analysis of extreme instances.


title: Modeling of Coal Drying before Pyrolysis

abstract:
  The coking process is composed of two main stages: drying process and
pyrolysis of coal. A heat and mass transfer model was developed to simulate the
drying process of coal. The mechanisms of heat and mass transfer described in
the model are: conduction through the coal cake; conduction and convection
through the gas in pores; generation, flux and condensation of water vapor. The
model has been implemented in finite element software. It requires basic data
on the coke oven charge properties and oven dimensions as input. These input
data were obtained by experiments or from the literature. The proposed model
includes condensation and evaporation allowing us to reproduce the temperature
plateau observed experimentally.


title: Ultrahigh Energy Neutrinos at the Pierre Auger Observatory

abstract:
  The observation of ultrahigh energy (UHE) neutrinos has become a priority in
experimental astroparticle physics. UHE neutrinos can be detected with a
variety of techniques. In particular, neutrinos can interact in the atmosphere
(downward-going neutrinos) or in the Earth crust (Earth-skimming neutrinos),
producing air showers that can be observed with arrays of detectors at the
ground. With the Surface Detector Array of the Pierre Auger Observatory we can
detect these types of cascades. The distinguishing signature for neutrino
events is the presence of very inclined showers produced close to the ground
(i.e. after having traversed a large amount of atmosphere). In this work we
review the procedure and criteria established to search for UHE neutrinos in
the data collected with the ground array of the Pierre Auger Observatory. This
includes Earth-skimming as well as downward-going neutrinos. No neutrino
candidates have been found, which allows us to place competitive limits to the
diffuse flux of UHE neutrinos in the EeV range and above.


title:
Growth and Investigation of Nd_{1-x}Sm_{x}ScO_{3} and
  Sm_{1-x}Gd_{x}ScO_{3} Solid-Solution Single Crystals

abstract:
  The pseudo-cubic lattice parameters of rare-earth (RE) scandate, REScO3,
single crystals grown by the Czochralski technique with RE=Dy to Pr lie between
about 3.95 and 4.02 Angstrom. These crystals are the only available perovskite
substrates in this lattice constant range that can withstand virtually any thin
film growth conditions. Two members of this series, PmScO3 and EuScO3, are,
however, not suitable for substrate applications. Because the pseudo-cubic
lattice parameters between neighbouring REScO3 compounds decrease with rising
atomic number of the RE in about 0.01 Angstrom steps, the unsuitability of
PmScO3 (radioactivity) and EuScO3 (incompatibility with Si) causes an
interruption in this lattice spacing sequence. To replace them, solid solutions
of their adjacent rare-earth scandates, i.e., (Nd0.5Sm0.5)ScO3 and
(Sm0.5Gd0.5)ScO3, were grown by the Czochralski method. Their average
pseudo-cubic lattice parameters of 3.9979 Angstrom and 3.9784 Angstrom are very
close to those of PmScO3 and EuScO3, respectively, and they show very low
segregation. These qualities make these solid solutions excellent substitutes
for PmScO3 and EuScO3.


title:
Hirota equations for the extended bigraded Toda hierarchy and the total
  descendent potential of CP^1 orbifolds

abstract:
  We prove that the Hirota quadratic equations of Milanov and Tseng define an
integrable hierarchy which is equivalent to the extended bigraded Toda
hierarchy. In particular this proves a conjecture of Milanov-Tseng that relates
the total descendent potential of the orbifold $C_{k,m}$ with a tau function of
the bigraded Toda hierarchy.


title:
Coevolution of dust, gas, and stars in galaxies - I. Spatial
  distributions and scaling-relations of dust and molecular hydrogen

abstract:
  We investigate the time evolution of dust properties, molecular hydrogen
(H_2) contents, and star formation histories in galaxies by using our original
chemodynamical simulations. The simulations include the formation of dust in
the stellar winds of supernovae (SNe) and asymptotic giant branch (AGB) stars,
the growth and destruction processes of dust in the interstellar medium (ISM),
the formation of polycyclic aromatic hydrocarbon (PAH) dust in carbon-rich AGB
stars, the H_2 formation on dust grains, and the H_2 photo-dissociation due to
far ultra-violet (FUV) light in a self-consistent manner. We focus mainly on
disk galaxies with different total masses in this preliminary study. The
principle results are as follows: The star formation histories of disk galaxies
can be regulated by the time evolution of interstellar dust, mainly because the
formation rates of H_2 can be controlled by dust properties. The observed
correlation between dust-to-gas-ratios (D) and gas-phase oxygen abundances (A_O
= 12+log(O/H)) can be reproduced reasonably well in the present models. The
disks show negative radial gradients (i.e., larger in inner regions) of H_2
fraction (f_H2), PAH-to-dust mass ratio (f_PAH), D, and A_O and these gradients
evolve with time. The surface-mass densities of dust (Sigma_dust) are
correlated more strongly with the total surface gas densities than with those
of H_2. Local gaseous regions with higher D are more likely to have higher f_H2
in individual disks and total H_2 masses correlate well with total dust masses.
More massive disk galaxies are more likely to have higher D, f_PAH, and f_H2
and smaller dust-to-stellar mass ratios. We also compare between galactic star
formation histories in the metallicity-dependent and dust-dependent star
formation models and find no major differences.


title:
Cohomological characterization of hyperquadrics of odd dimensions in
  characteristic two

abstract:
  We consider characterizations of projective varieties in terms of their
tangents. S. Mori established the characterization of projective spaces in
arbitrary characteristic by ampleness of tangent bundles. J. Wahl characterized
projective spaces in characteristic zero by cohomological condition of tangent
bundles; in addition, he remarked that a counter-example in characteristic two
is constructed from odd-dimensional hyperquadrics $Q_{2n-1}$ with $n > 1$. This
is caused by existence of a common point in $\mathbb{P}^{2n}$ which every
embedded tangent space to the quadric contains. In general, a projective
variety in $\mathbb{P}^N$ is said to be strange if its embedded tangent spaces
admit such a common point in $\mathbb{P}^N$. A non-linear smooth projective
curve is strange if and only if it is a conic in characteristic two (E. Lluis,
P. Samuel). S. Kleiman and R. Piene showed that a non-linear smooth
hypersurface in $\mathbb{P}^N$ is strange if and only if it is a quadric of
odd-dimension in characteristic two. In this paper, we investigate complete
intersection varieties, and prove that, a non-linear smooth complete
intersection variety in $\mathbb{P}^N$ is strange if and only if it is a
quadric in $\mathbb{P}^N$ of odd dimension in characteristic two; these
conditions are also equivalent to non-vanishing of 0-cohomology of (-1)-twist
of the tangent bundle.


title: Single-file diffusion with non-thermal initial conditions

abstract:
  Single-file diffusion is a theoretically challenging many-body problem where
the calculation of even the simplest observables, e.g. mean square
displacement, for a tracer particle requires a heavy mathematical machinery.
There is therefore a need for simple approaches which predict qualitatively
correct behaviours. Here we put forward one such method which we use to
investigate the influence of non-thermal initial conditions on the dynamics of
a tracer particle. With our new approach we reproduce, up to scaling, several
known asymptotic results for the tracer particle mean square displacement.


title: Semantic Tagging on Historical Maps

abstract:
  Tags assigned by users to shared content can be ambiguous. As a possible
solution, we propose semantic tagging as a collaborative process in which a
user selects and associates Web resources drawn from a knowledge context. We
applied this general technique in the specific context of online historical
maps and allowed users to annotate and tag them. To study the effects of
semantic tagging on tag production, the types and categories of obtained tags,
and user task load, we conducted an in-lab within-subject experiment with 24
participants who annotated and tagged two distinct maps. We found that the
semantic tagging implementation does not affect these parameters, while
providing tagging relationships to well-defined concept definitions. Compared
to label-based tagging, our technique also gathers positive and negative
tagging relationships. We believe that our findings carry implications for
designers who want to adopt semantic tagging in other contexts and systems on
the Web.


title: The freeness problem over matrix semigroups and bounded languages

abstract:
  We study the freeness problem for matrix semigroups. We show that the
freeness problem is decidable for upper-triangular $2\times 2$ matrices with
rational entries when the products are restricted to certain bounded languages.


title:
Alternative Scenarios of Relativistic Heavy-Ion Collisions: II. Particle
  Production

abstract:
  Particle production in relativistic collisions of heavy nuclei is analyzed in
a wide range of incident energies 2.7 GeV $\le \sqrt{s_{NN}}\le$ 62.4 GeV. The
analysis is performed within the three-fluid model employing three different
equations of state (EoS): a purely hadronic EoS, an EoS with the first-order
phase transition and that with a smooth crossover transition. It is found that
the hadronic scenario fails to reproduce experimental yields of antibaryons
(strange and nonstrange), starting already from lower SPS energies, i.e.
$\sqrt{s_{NN}}>$ 5 GeV. Moreover, at energies above the top SPS one, i.e.
$\sqrt{s_{NN}}>$ 17.4 GeV, the mid-rapidity densities predicted by the hadronic
scenario considerably exceed the available RHIC data on all species. At the
same time the deconfinement-transition scenarios reasonably agree (to a various
extent) with all the data. The present analysis demonstrates certain advantage
of the deconfinement-transition EoS's. However, all scenarios fail to reproduce
the strangeness enhancement in the incident energy range near 30A GeV (i.e. a
horn anomaly in the $K^+/\pi^+$ ratio) and yields of $\phi$-mesons at 20A--40A
GeV.


title: Rigid polyboxes and Keller's conjecture

abstract:
  A cube tiling of R^d is a family of pairwise disjoint cubes
$[0,1)^d+T=\{[0,1)^d+t:t\in T\}$ such that $\bigcup_{t\in T}([0,1)^d+t)=R^d$.
Two cubes $[0,1)^d+t$, $[0,1)^d+s$ are called a twin pair if their closures
have a complete facet in common, that is if $|t_j-s_j|=1$ for some $j\in
[d]=\{1,..., d\}$ and $t_i=s_i$ for every $i\in [d]\setminus \{j\}$. In 1930,
Keller conjectured that in every cube tiling of R^d there is a twin pair.
Keller's conjecture is true for dimensions $d\leq 6$ and false for all
dimensions $d\geq 8$. For $d=7$ the conjecture is still open. Let $x\in R^d$,
$i\in [d]$, and let L(T,x,i) be the set of all $i$th coordinates $t_i$ of
vectors $t\in T$ such that $([0,1)^d+t)\cap ([0,1]^d+x)\neq \emptyset$ and
$t_i\leq x_i$. Let $r^-(T)=\min_{x\in R^d}\; \max_{1\leq i\leq d}|L(T,x,i)|$
and $r^+(T)=\max_{x\in R^d}\; \max_{1\leq i\leq d}|L(T,x,i)|$. It is known that
Keller's conjecture is true in dimension seven for cube tilings $[0,1)^7+T$ for
which $r^-(T)\leq 2$. In the present paper we show that it is also true for
$d=7$ if $r^+(T)\geq 6$. Thus, if $[0,1)^d+T$ is a counterexample to Keller's
conjecture in dimension seven, then $r^-(T),r^+(T)\in \{3,4,5\}$.


title: Null weak values in multi-level systems

abstract:
  A two-step measurement protocol of a quantum system, known as weak value
(WV), has been introduced more than two decades ago by Aharonov et al. [1], and
has since been studied in various contexts. Here we discuss another two-step
measurement protocol which we dub null weak value (NWV). The protocol consists
of a partial-collapse measurement followed by quantum manipulation on the
system and finally a strong measurement. The first step is a strong measurement
which takes place with small probability. The second strong measurement is used
as postselection on the outcome of the earlier step. Not being measured in the
partial-collapse stage (null outcome) leads to a non-trivial correlation
between the two measurements. The NVW protocol, first defined for a two-level
system [2], is generalized to a multi-level system, and compared to the
standard-WV protocol.


title: Tetrahedron equation and cyclic quantum dilogarithm identities

abstract:
  We establish a hierarchy of quantum dilogarithm identities associated to a
sequence of triangular shaped quivers. The tetrahedron equation plays a key
role in our construction.


title: Standard and Null Weak Values

abstract:
  Weak value (WV) is a quantum mechanical measurement protocol, proposed by
Aharonov, Albert, and Vaidman. It consists of a weak measurement, which is
weighed in, conditional on the outcome of a later, strong measurement. Here we
define another two-step measurement protocol, null weak value (NVW), and point
out its advantages as compared to WV. We present two alternative derivations of
NWVs and compare them to the corresponding derivations of WVs.


title: Non-perturbative aspects of gauge/gravity duality

abstract:
  Recently we provided a microscopic derivation of the exact supergravity
profile for the twisted scalar field emitted by systems of fractional D3-branes
at a Z2 orbifold singularity. In this contribution we focus on a set-up
supporting an N = 2 SYM theory with SU(2) gauge group and Nf=4. We take into
account the tower of D-instanton corrections to the source terms for the
twisted scalar and find that its profile can be expressed in terms of the
chiral ring elements of the gauge theory. We show how the twisted scalar, which
at the perturbative level represents the gravity counterpart of the gauge
coupling, at the non-perturbative level is related to the effective gauge
coupling in an interestingly modified way.


title:
Aperture corrections for disk galaxy properties derived from the CALIFA
  survey. Balmer emission lines in spiral galaxies

abstract:
  This work investigates the effect of the aperture size on derived galaxy
properties for which we have spatially-resolved optical spectra. We focus on
some indicators of star formation activity and dust attenuation for spiral
galaxies that have been widely used in previous work on galaxy evolution. We
have used 104 spiral galaxies from the CALIFA survey for which 2D spectroscopy
with complete spatial coverage is available. From the 3D cubes we have derived
growth curves of the most conspicuous Balmer emission lines (Halpha, Hbeta) for
circular apertures of different radii centered at the galaxy's nucleus after
removing the underlying stellar continuum. We find that the Halpha flux
(f(Halpha)) growth curve follows a well defined sequence with aperture radius
showing low dispersion around the median value. From this analysis, we derive
aperture corrections for galaxies in different magnitude and redshift
intervals. Once stellar absorption is properly accounted for, the
f(Halpha)/f(Hbeta) ratio growth curve shows a smooth decline, pointing towards
the absence of differential dust attenuation as a function of radius. Aperture
corrections as a function of the radius are provided in the interval
[0.3,2.5]R_50. Finally, the Halpha equivalent width (EW(Halpha)) growth curve
increases with the size of the aperture and shows a very large dispersion for
small apertures. This large dispersion prevents the use of reliable aperture
corrections for this quantity. In addition, this result suggests that
separating star-forming and quiescent galaxies based on observed EW(Halpha)
through small apertures is likely to result in low EW(Halpha) star-forming
galaxies begin classified as quiescent.


title:
Configuration-interaction Monte Carlo method and its application to the
  trapped unitary Fermi gas

abstract:
  We develop a quantum Monte Carlo method to estimate the ground-state energy
of a fermionic many-particle system in the configuration-interaction shell
model approach. The fermionic sign problem is circumvented by using a guiding
wave function in Fock space. The method provides an upper bound on the
ground-state energy whose tightness depends on the choice of the guiding wave
function. We argue that the antisymmetric geminal product class of wave
functions is a good choice for guiding wave functions. We demonstrate our
method for the trapped two-species fermionic cold atom system in the unitary
regime of infinite scattering length using the particle-number projected
Hartree-Fock-Bogoliubov wave function as the guiding wave function. We estimate
the ground-state energy and energy-staggering pairing gap as a function of the
number of particles. Our results compare favorably with exact numerical
diagonalization results and with previous coordinate-space Monte Carlo
calculations.


title: Systems of Differential Operators and Generalized Verma Modules

abstract:
  In this paper we close the cases that were left open in our earlier works on
the study of conformally invariant systems of second-order differential
operators for degenerate principal series. More precisely, for these cases, we
find the special values of the systems of differential operators, and determine
the standardness of the homomorphisms between the generalized Verma modules,
that come from the conformally invariant systems.


title: Some Hierarchies of QCB_0-Spaces

abstract:
  We define and study hierarchies of topological spaces induced by the
classical Borel and Luzin hierarchies of sets. Our hierarchies are divided into
two classes: hierarchies of countably based spaces induced by their embeddings
into the domain P\omega, and hierarchies of spaces (not necessarily countably
based) induced by their admissible representations. We concentrate on the
non-collapse property of the hierarchies and on the relationships between
hierarchies in the two classes.


title:
Explicit Reduced-Order Integral Formulations of State and Parameter
  Estimation Problems for a Class of Nonlinear Systems

abstract:
  We propose a technique for reformulation of state and parameter estimation
problems as that of matching explicitly computable definite integrals with
known kernels to data. The technique applies for a class of systems of
nonlinear ordinary differential equations and is aimed to exploit parallel
computational streams in order to increase speed of calculations. The idea is
based on the classical adaptive observers design. It has been shown that in
case the data is periodic it may be possible to reduce dimensionality of the
inference problem to that of the dimension of the vector of parameters entering
the right-hand side of the model nonlinearly. Performance and practical
implications of the method are illustrated on a benchmark model governing
dynamics of voltage in generated in barnacle giant muscle.


title: Trust Estimation in Peer-to-Peer Network Using BLUE

abstract:
  In peer-to-peer networks, free riding is a major problem. Reputation
management systems can be used to overcome this problem. Reputation estimation
methods generally do not consider the uncertainties in the inputs. We propose a
reputation estimation method using BLUE (Best Linear Unbiased estimator)
estimator that consider uncertainties in the input variables.


title: Multistability and Self-Organization in Disordered SQUID Metamaterials

abstract:
  Planar arrays of magnetoinductively coupled rf SQUIDs belong to the emergent
class of superconducting metamaterials that encompass the Josephson effect.
SQUID metamaterials acquire their electromagnetic properties from the resonant
characteristics of their constitutive elements, i.e., the individual rf SQUIDs,
which consist of a superconducting ring interrupted by a Josephson junction. We
investigate the response of a two-dimensional SQUID metamaterial to frequency
variation of an applied alternating magnetic field in the presence of disorder,
arising from critical current fluctuations of the Josephson elements; in
effect, the resonance frequencies of individual SQUIDs are distributed randomly
around a mean value. Bistability is observed in the total current-frequency
curves both in ordered and disordered SQUID metamaterials; moreover,
bistability is favoured by disorder through the improvement of synchronization
between SQUID oscillators. Relatively weak disorder widens significantly the
bistability region by helping the system to self-organize itself and leads to
nearly homogeneous states that change smoothly with varying frequency.
Moreover, the total current of the metamaterial is enhanced compared with that
of uncoupled SQUIDs, through the synergetic action of coupling and
synchronization. Multistability of nearly homogeneous states allows the
metamaterial to exhibit different magnetic responses corresponding to different
values of the magnetic permeability. At low power of the incident field,
high-current states exhibit extreme diamagnetic properties corresponding to
negative magnetic permeability in a narrow frequency region.


title: Particle identification using clustering algorithms

abstract:
  A method that uses fuzzy clustering algorithms to achieve particle
identification based on pulse shape analysis is presented. The fuzzy c-means
clustering algorithm is used to compute mean (principal) pulse shapes induced
by different particle species in an automatic and unsupervised fashion from a
mixed set of data. A discrimination amplitude is proposed using these principal
pulse shapes to identify the originating particle species of a detector pulse.
Since this method does not make any assumptions about the specific features of
the pulse shapes, it is very generic and suitable for multiple types of
detectors. The method is applied to discriminate between photon- and
proton-induced signals in CsI(Tl) scintillator detectors and the results are
compared to the well-known integration method.


title:
Gradient dynamical systems on open surfaces and critical points of
  Green's functions

abstract:
  We study the dynamics of the vector field on an open surface given by the
gradient of a Green's function. This dynamical approach enables us to show that
this field induces an invariant decomposition of the surface as the union of a
disk and a 1-skeleton that encodes the topology of the surface. We analyze the
structure of this 1-skeleton, thereby obtaining, in particular, a topological
upper bound for the number of critical points a Green's function can have.
Connections between the dynamical properties of the gradient field and the
conformal structure of the surface are also discussed.


title:
X-ray emission from the luminous O-type subdwarf HD 49798 and its
  compact companion

abstract:
  The X-ray source RX J0648.0-4418 is the only confirmed binary system in which
a compact object, most likely a massive white dwarf, accretes from a hot
subdwarf companion, the bright sdO star HD 49798. The X-ray emission from this
system is characterized by two periodic modulations caused by an eclipse, at
the orbital period of 1.55 d, and by the rotation of the compact object with a
spin period of 13.2 s. In 2011 we obtained six short XMM-Newton observations
centered at orbital phase 0.75, in order to study the system during the
eclipse, and spaced at increasingly long time intervals in order to obtain an
accurate measure of the spin-period evolution through phase-connected timing.
The duration of the eclipse ingress and egress, 500 s, indicates the presence
of an X-ray emitting region with dimensions of the order of a few 10^4 km,
surrounding the pulsar and probably due to scattering in the companion's wind.
We derived an upper limit on the spin-period derivative |Pdot|<6x10^-15 s/s,
more than two orders of magnitude smaller than the previously available value.
Significant X-ray emission is detected also during the 1.2 hours-long eclipse,
with a luminosity of about 3x10^30 erg/s. The eclipse spectrum shows prominent
emission lines of H- and He-like nitrogen, an overabundant element in HD 49798.
These findings support the suggestion that the X-ray emission observed during
the eclipse originates in HD 49798 and that the processes responsible for X-ray
emission in the stellar winds of massive O stars are also at work in the much
weaker winds of hot subdwarfs.


title: Five models for lepton mixing

abstract:
  We produce five flavour models for the lepton sector. All five models fit
perfectly well---at the one-sigma level---the existing data on the neutrino
mass-squared differences and on the lepton mixing angles. The models are based
on the type-I seesaw mechanism, on a Z_2 symmetry for each lepton flavour, and
either on a (spontaneously broken) symmetry under the interchange of two lepton
flavours or on a (spontaneously broken) CP symmetry incorporating that
interchange---or on both symmetries simultaneously. Each model makes definite
predictions both for the scale of the neutrino masses and for the phase delta
in lepton mixing; the fifth model also predicts a correlation between the
lepton mixing angles theta_12 and theta_23.


title:
Measurement of direct CP violation parameters in B^+/- -> J/\psi K^+/-
  and B^+/- ->J/psi pi^+/- decays with 10.4 fb^-1 of Tevatron data

abstract:
  We present a measurement of the direct CP-violating charge asymmetry in B^+/-
mesons decaying to J/psi K^+/- and J/psi pi^+/- where J/psi decays to mu^+
mu^-, using the full Run II data set of 10.4 fb^-1 of proton-antiproton
collisions collected using the D0 detector at the Fermilab Tevatron Collider. A
difference in the yield of B^- and B^+ mesons in these decays is found by
fitting to the difference between their reconstructed invariant mass
distributions resulting in asymmetries of ajpk =[0.59 +/- 0.37]%, which is the
most precise measurement to date, and ajppi= [-4.2 +/- 4.5]%. Both measurements
are consistent with standard model predictions.


title:
Multihistogram Reweighting for Nonequilibrium Markov Processes Using
  Sequential Importance Sampling Methods

abstract:
  We present a multihistogram reweighting technique for nonequilibrium Markov
Chains with discrete energies. The method generalizes the single histogram
method of Yin et al. [Phys. Rev. E72, 036122 (2005)], making it possible to
calculate the time evolution of observables at a posteriori chosen couplings
based on a set of simulations performed at other couplings. In the same way as
multihistogram reweighting in an equilibrium setting improves the practical
reweighting range as well as use of available data compared to single histogram
reweighting, the method generalizes the multihistogram advantages to
nonequilibrium simulations. We demonstrate the procedure for the Ising model
with Metropolis dynamics, but stress that the method is generally applicable to
a range of models and Monte Carlo update schemes.


title:
Limiting effects of geometrical and optical nonlinearities on the
  squeezing in optomechanics

abstract:
  In recent experiments, the re-thermalization time of the mechanical resonator
is stated as the limiting factor for quantum applications of optomechanical
systems. To explain the origin of this limitation, an analytical nonlinear
investigation supported by the recent successful experimental laser cooling
parameters is carried out in this work. To this end, the effects of geometrical
and the optical nonlinearities on the squeezing are studied and are in a good
agreement with the experimental results. It appears that highly squeezed state
are generated where these nonlinearities are minimized and that high
nonlinearities are limiting factors to reach the quantum ground state.


title:
Beyond Nash Equilibrium in Open Spectrum Sharing: Lorenz Equilibrium in
  Discrete Games

abstract:
  A new game theoretical solution concept for open spectrum sharing in
cognitive radio (CR) environments is presented, the Lorenz equilibrium (LE).
Both Nash and Pareto solution concepts have limitations when applied to real
world problems. Nash equilibrium (NE) rarely ensures maximal payoff and it is
frequently Pareto inefficient. The Pareto set is usually a large set of
solutions, often too hard to process. The Lorenz equilibrium is a subset of
Pareto efficient solutions that are equitable for all players and ensures a
higher payoff than the Nash equilibrium. LE induces a selection criterion of
NE, when several are present in a game (e.g. many-player discrete games) and
when fairness is an issue. Besides being an effective NE selection criterion,
the LE is an interesting game theoretical situation per se, useful for CR
interaction analysis.


title: Periodicity of betti numbers of monomial curves

abstract:
  Let $K$ be an arbitrary field. Let $\a = (a_1< ... <a_n)$ be a sequence of
positive integers. Let $C(\a)$ be the affine monomial curve in ${\mathbb A}^n$
parametrized by $t\to (t^{a_1}, ..., t^{a_n})$. Let $I(\a)$ be the defining
ideal of $C(\a)$ in $K[x_1, ..., x_n]$. For each positive integer $j$, let
$\a+j$ be the sequence $(a_1 + j, ..., a_n+j)$. In this paper, we prove the
conjecture of Herzog and Srinivasan saying that the betti numbers of $I(\a +
j)$ are eventually periodic in $j$ with period $a_n -a_1$. When $j$ is large
enough, we describe the betti table for the closure of $C(\a+j)$ in $\PP^n$.


title:
Observation of the Spatial Distribution of Gravitationally Bound Quantum
  States of Ultracold Neutrons and Its Derivation Using the Wigner Function

abstract:
  Ultracold neutrons (UCNs) can be bound by the potential of terrestrial
gravity and a reflecting mirror. The wave function of the bound state has
characteristic modulations. We carried out an experiment to observe the
vertical distribution of the UCNs above such a mirror at Institut Laue-Langevin
in 2011. The observed modulation is in good agreement with that prediction by
quantum mechanics using the Wigner function. The spatial resolution of the
detector system is estimated to be 0.7 micro meter. This is the first
observation of gravitationally bound states of UCNs with submicron spatial
resolution.


title: Condensation Energy of a Spin-1/2 Strongly Interacting Fermi Gas

abstract:
  We report a measurement of the condensation energy of a two-component Fermi
gas with tunable interactions. From the equation of state of the gas, we infer
the properties of the normal phase in the zero-temperature limit. By comparing
the pressure of the normal phase at T=0 to that of the low-temperature
superfluid phase, we deduce the condensation energy, i.e. the energy gain of
the system in being in the superfluid rather than normal state. We compare our
measurements to a ladder approximation description of the normal phase, and to
a fixed node Monte-Carlo approach, finding excellent agreement. We discuss the
relationship between condensation energy and pairing gap in the BEC-BCS
crossover.


title: Absolutely homotopy-cartesian squares

abstract:
  We call a diagram D absolutely cartesian if F(D) is homotopy cartesian for
all homotopy functors F. This is a sensible notion for diagrams in categories C
where Goodwillie's calculus of functors may be set up for functors with domain
C. We prove a classification theorem for absolutely cartesian squares of spaces
and state a conjecture of the classification for higher dimensional cubes.


title:
Nucleation of a stable solid from melt in the presence of multiple
  metastable intermediate phases: Wetting, Ostwald step rule and vanishing
  polymorphs

abstract:
  In many systems, nucleation of a stable solid may occur in the presence of
other (often more than one) metastable phases. These may be polymorphic solids
or even liquid phases. In such cases, nucleation of the solid phase from the
melt may be facilitated by the metastable phase because the latter can "wet"
the interface between the parent and the daughter phases, even though there may
be no signature of the existence of metastable phase in the thermodynamic
properties of the parent liquid and the stable solid phase. Straightforward
application of classical nucleation theory (CNT) is flawed here as it
overestimates the nucleation barrier since surface tension is overestimated (by
neglecting the metastable phases of intermediate order) while the thermodynamic
free energy gap between daughter and parent phases remains unchanged. In this
work we discuss a density functional theory (DFT) based statistical mechanical
approach to explore and quantify such facilitation. We construct a simple order
parameter dependent free energy surface that we then use in DFT to calculate
(i) the order parameter profile, (ii) the overall nucleation free energy
barrier and (iii) the surface tension between the parent liquid and the
metastable solid and also parent liquid and stable solid phases. The theory
indeed finds that the nucleation free energy barrier can decrease significantly
in the presence of wetting. This approach can provide a microscopic explanation
of Ostwald step rule and the well-known phenomenon of "disappearing polymorphs"
that depends on temperature and other thermodynamic conditions. Theory reveals
a diverse scenario for phase transformation kinetics some of which may be
explored via modern nanoscopic synthetic methods.


title: A 2 hour periodic variation in the low mass X-ray binary Ser X-1

abstract:
  Spectroscopy of the low mass X-ray binary Ser X-1 using the Gran Telescopio
Canarias have revealed a ~2 hr periodic variability that is present in the
three strongest emission lines. We tentatively interpret this variability as
due to orbital motion, making it the first indication of the orbital period of
Ser X-1. Together with the fact that the emission lines are remarkably narrow,
but still resolved, we show that a main sequence K-dwarf together with a
canonical 1.4Msun neutron star gives a good description of the system. In this
scenario the most likely place for the emission lines to arise is the accretion
disk, instead of a localized region in the binary (such as the irradiated
surface or the stream-impact point), and their narrowness is due instead to the
low inclination (<10 degrees) of Ser X-1.


title: Why Mass Media Matter to Planning Research: The Case of Megaprojects

abstract:
  This article asks how planning scholarship may effectively gain impact in
planning practice through media exposure. In liberal democracies the public
sphere is dominated by mass media. Therefore, working with such media is a
prerequisite for effective public impact of planning research. Using the
example of megaproject planning, it is illustrated how so-called "phronetic
planning research," which explicitly incorporates in its methodology active and
strategic collaboration with media, may be helpful in generating change in
planning practice via the public sphere. Main lessons learned are: (1) Working
with mass media is an extremely cost-effective way to increase the impact of
planning scholarship on practice; (2) Recent developments in information
technology and social media have made impact via mass media even more
effective; (3) Research on "tension points," i.e., points of potential
conflict, are particularly interesting to media and the public, and are
especially likely to generate change in practice; and (4) Tension points bite
back; planning researchers should be prepared for, but not afraid of, this.


title:
SPIDAST: a new modular software to process spectro-interferometric
  measurements

abstract:
  Extracting stellar fundamental parameters from SPectro-Interferometric (SPI)
data requires reliable estimates of observables and with robust uncertainties
(visibility, triple product, phase closure). A number of fine calibration
procedures is necessary throughout the reduction process. Testing departures
from centro-symmetry of brightness distributions is a useful complement.
Developing a set of automatic routines, called SPIDAST (made available to the
community) to reduce, calibrate and interpret raw data sets of instantaneous
spectro-interferograms at the spectral channel level, we complement (and in
some respects improve) the ones contained in the amdlib Data Reduction
Software. Our new software SPIDAST is designed to work in an automatic mode,
free from subjective choices, while being versatile enough to suit various
processing strategies. SPIDAST performs the following automated operations:
weighting of non-aberrant SPI data (visibility, triple product), fine spectral
calibration (sub-pixel level), accurate and robust determinations of stellar
diameters for calibrator sources (and their uncertainties as well), correction
for the degradations of the interferometer response in visibility and triple
product, calculation of the Centro-Symmetry Parameter (CSP) from the calibrated
triple product, fit of parametric chromatic models on SPI observables, to
extract model parameters. SPIDAST is currently applied to the scientific study
of 18 cool giant and supergiant stars, observed with the VLTI/AMBER facility at
medium resolution in the K band. Because part of their calibrators have no
diameter in the current catalogs, SPIDAST provides new determinations of the
angular diameters of all calibrators. Comparison of SPIDAST final calibrated
observables with amdlib determinations shows good agreement, under good and
poor seeing conditions.


title: Spinning dark matter halos promote bar formation

abstract:
  Stellar bars are the most common non-axisymmetric structures in galaxies and
their impact on the evolution of disc galaxies at all cosmological times can be
significant. Classical theory predicts that stellar discs are stabilized
against bar formation if embedded in massive spheroidal dark matter halos.
However, dark matter halos have been shown to facilitate the growth of bars
through resonant gravitational interaction. Still, it remains unclear why some
galaxies are barred and some are not. In this study, we demonstrate that
co-rotating (i.e., in the same sense as the disc rotating) dark matter halos
with spin parameters in the range of $0 \le \lambda_{\mathrm{dm}} \le 0.07$ -
which are a definite prediction of modern cosmological models - promote the
formation of bars and boxy bulges and therefore can play an important role in
the formation of pseudobulges in a kinematically hot dark matter dominated disc
galaxies. We find continuous trends for models with higher halo spins: bars
form more rapidly, the forming slow bars are stronger, and the final bars are
longer. After 2 Gyrs of evolution, the amplitude of the bar mode in a model
with $\lambda_{\mathrm{dm}} = 0.05$ is a factor of ~6 times higher, A_2/A_0 =
0.23, than in the non-rotating halo model. After 5 Gyrs, the bar is ~ 2.5 times
longer. The origin of this trend is that more rapidly spinning (co-rotating)
halos provide a larger fraction of trailing dark matter particles that lag
behind the disc bar and help growing the bar by taking away its angular
momentum by resonant interactions. A counter-rotating halo suppresses the
formation of a bar in our models. We discuss potential consequences for forming
galaxies at high-redshift and present day low mass galaxies which have
converted only a small fraction of their baryons into stars.


title:
Reconciling quantum trajectories and stationary quantum distributions in
  single-photon polarization states

abstract:
  The question of the representation of quantum stationary partially polarized
waves as random superpositions of different polarization ellipses is addressed.
To this end, the Bohmian formulation of quantum mechanics is considered and
extended to quantum optical polarization. As is shown, this approach properly
combines definite time-evolving trajectories with rigorous stationary quantum
distributions via the topology displayed by the associated phase field.


title: Kinematics of the intermediate mass black hole candidate HLX-1

abstract:
  We studied the optical spectrum of HLX-1 during its latest outburst, using
the FORS2 spectrograph on the Very Large Telescope. We detect an Halpha
emission line centered at lambda = (6718.9 +/- 0.9) Ang and find that its
projected radial velocity with respect to the nucleus of ESO243-49 is (424 +/-
27) km/s, while the maximum rotational velocity of the stars in that galaxy is
~209 km/s. This suggests that HLX-1 and its surrounding stars were not formed
in situ, but came either from a disrupted dwarf galaxy or from a nuclear
recoil. We also find that the Halpha emission line is resolved with full width
at half maximum ~400 km/s, suggesting a nebular rather than disk origin for the
emission. Its luminosity (L_{Halpha} ~ a few 10^{37} erg/s, equivalent width
~70 Ang) is also consistent with emission from a nebula photo-ionized by HLX-1.


title:
Structural, electronic properties and stability of MXenes Ti2C and Ti3C2
  functionalized by methoxy groups

abstract:
  The properties of MXenes, a new group of quasi-two-dimensional d-metal
carbide or nitride nanomaterials derived by chemical exfoliation from the MAX
phases, can be very sensitive to the presence of surface functional groups.
Herein, the MXenes Ti2C and Ti3C2 functionalized by methoxy groups are
considered by means of the density functional theory tight-binding method.
Their structural, electronic properties, and relative stability are discussed
in comparison with related and experimentally fabricated hydroxy derivatives of
MXenes.


title:
Electrical spin injection from ferromagnet into an InAs heterostructures
  through MgO tunnel barrier

abstract:
  We have investigated electrical spin injection from Ni81Fe19 into an InAs
quantum well through MgO tunneling barrier for potential application to
InAs-based spin field effect transistor. Injected spin polarized current were
detected in both nonlocal and local spin valve set-ups and the spin diffusion
length and spin injection efficiency were analyzed. The spin diffusion length
was estimated to be 1.6 {\mu}m in nonlocal set-up at 1.4 K. The spin
polarization of Ni81Fe19/MgO/InAs as-deposited sample was relealed to be 6.9 %,
while increased spin polarization of 8.9 % was observed by additional thermal
treatment.


title: Simulated Car Racing Championship: Competition Software Manual

abstract:
  This manual describes the competition software for the Simulated Car Racing
Championship, an international competition held at major conferences in the
field of Evolutionary Computation and in the field of Computational
Intelligence and Games. It provides an overview of the architecture, the
instructions to install the software and to run the simple drivers provided in
the package, the description of the sensors and the actuators.


title:
2D titanium carbonitrides and their hydroxylated derivatives:
  Structural, electronic properties and stability of MXenes Ti3C2-xNx and
  Ti3C2-xNx(OH)2

abstract:
  3D titanium carbonitrides TiCxNy possess excellent physical, chemical, and
mechanical properties, attractive for various industrial applications. Most
recently, the uncommon nano-sized layers of 2D-like titanium carbonitrides were
fabricated from MAX phases. Herein, the structural, electronic properties and
stability of these new compounds as well as their hydroxylated derivatives -
so-called MXenes Ti3C2-xNx and Ti3C2-xNx(OH)2 are probed by means of SSC-DFTB
calculations. The genesis of the properties is discussed in the sequence:
binary MXenes Ti3C2 (Ti3N2) -> their hydroxylated forms Ti3C2(OH)2 (Ti3N2(OH)2)
-> pristine MXene Ti3C2-xNx -> hydroxylated Ti3C2-xNx(OH)2. Our results show
that the examined materials are metallic-like. The most favorable type of
OH-covering is presented by the occupation of the hollow sites between three
neighboring carbon (nitrogen) atoms. The formation of 2D MXene carbonitrides
with random distribution of C and N atoms was found to be thermodynamically
more favorable.


title:
Isoperimetric type problems and Alexandrov-Fenchel type inequalities in
  the hyperbolic space

abstract:
  In this paper, we solve various isoperimetric problems for the
quermassintegrals and the curvature integrals in the hyperbolic space $\H^n$,
by using quermassintegral preserving curvature flows. As a byproduct, we obtain
hyperbolic Alexandrov-Fenchel inequalities.


title:
Self-organization and solution of shortest-path optimization problems
  with memristive networks

abstract:
  We show that memristive networks-namely networks of resistors with memory-can
efficiently solve shortest-path optimization problems. Indeed, the presence of
memory (time non-locality) promotes self organization of the network into the
shortest possible path(s). We introduce a network entropy function to
characterize the self-organized evolution, show the solution of the
shortest-path problem and demonstrate the healing property of the solution
path. Finally, we provide an algorithm to solve the traveling salesman problem.
Similar considerations apply to networks of memcapacitors and meminductors, and
networks with memory in various dimensions.


title: Research on Potential Semantic Web Service Discovery Mechanisms

abstract:
  The field of Web services is an important paradigm in distributed application
development. Currently, many businesses are seeking to convert their
applications into web services because of its ability to promote
inter-operability among applications. As a number of web services increase, the
process of discovering appropriate web services for consumption from user's
perspective gains importance. In this paper, we present a study of potential
ways of discovering web services and issues related to each of them. In
addition, we discuss ontology concepts and related technologies, which
incorporate semantic meaning and hence give domain knowledge about a web
service to improve the discovery mechanism. The paper also presents an overview
of related research work, identifying metrics useful in filtering web service
search mechanisms.


title:
Bug Classification: Feature Extraction and Comparison of Event Model
  using Na\"ive Bayes Approach

abstract:
  In software industries, individuals at different levels from customer to an
engineer apply diverse mechanisms to detect to which class a particular bug
should be allocated. Sometimes while a simple search in Internet might help, in
many other cases a lot of effort is spent in analyzing the bug report to
classify the bug. So there is a great need of a structured mining algorithm -
where given a crash log, the existing bug database could be mined to find out
the class to which the bug should be allocated. This would involve Mining
patterns and applying different classification algorithms. This paper focuses
on the feature extraction, noise reduction in data and classification of
network bugs using probabilistic Na\"ive Bayes approach. Different event models
like Bernoulli and Multinomial are applied on the extracted features. When new,
unseen bugs are given as input to the algorithms, the performance comparison of
different algorithms is done on the basis of accuracy and recall parameters.


title: Phases, Flops and F-theory: SU(5) Gauge Theories

abstract:
  We consider F-theory and M-theory compactifications on singular Calabi-Yau
fourfolds with an SU(5) singularity. On the M-theory side this realizes
three-dimensional N=2 supersymmetric gauge theories with matter, and
compactification on a resolution of the fourfold corresponds to passing to the
Coulomb branch of the gauge theory. The classical phase structure of these
theories has a simple characterization in terms of subwedges of the fundamental
Weyl chamber of the gauge group. This phase structure has a counterpart in the
network of small resolutions of the Calabi-Yau fourfold. We determine the
geometric realization of each phase, which crucially depends on the fiber
structure in codimension 2 and 3, including the network structure, which is
realized in terms of flop transitions. This results in a set of small
resolutions, which do not have a standard algebraic or toric realization, but
are obtained by flops along codimension 2 (matter) loci.


title: Intrinsic universality in tile self-assembly requires cooperation

abstract:
  We prove a negative result on the power of a model of algorithmic
self-assembly for which it has been notoriously difficult to find general
techniques and results. Specifically, we prove that Winfree's abstract Tile
Assembly Model, when restricted to use noncooperative tile binding, is not
intrinsically universal. This stands in stark contrast to the recent result
that, via cooperative binding, the abstract Tile Assembly Model is indeed
intrinsically universal. Noncooperative self-assembly, also known as
"temperature 1", is where tiles bind to each other if they match on one or more
sides, whereas cooperative binding requires binding on multiple sides. Our
result shows that the change from single- to multi-sided binding qualitatively
improves the kinds of dynamics and behavior that these models of nanoscale
self-assembly are capable of. Our lower bound on simulation power holds in both
two and three dimensions; the latter being quite surprising given that
three-dimensional noncooperative tile assembly systems simulate Turing
machines. On the positive side, we exhibit a three-dimensional noncooperative
self-assembly tile set capable of simulating any two-dimensional noncooperative
self-assembly system.
  Our negative result can be interpreted to mean that Turing universal
algorithmic behavior in self-assembly does not imply the ability to simulate
arbitrary algorithmic self-assembly processes.


title: Degree powers in $C_5$-free graphs

abstract:
  Let $G$ be a graph with degree sequence $d_1,d_2,\ldots,d_n$. Given a
positive integer $p$, denote by $e_p(G)=\sum_{i=1}^n d_i^p$. Caro and Yuster
introduced a Tur\'an-type problem for $e_p(G)$: given an integer $p$, how large
can $e_p(G)$ be if $G$ has no subgraph of a particular type. They got some
results for the subgraph of particular type to be a clique of order $r+1$ and a
cycle of even length, respectively. Denote by $ex_p(n,H)$ the maximum value of
$e_p(G)$ taken over all graphs with $n$ vertices that do not contain $H$ as a
subgraph. Clearly, $ex_1(n,H)=2ex(n,H)$, where $ex(n,H)$ denotes the classical
Tur\'an number. In this paper, we consider $ex_p(n, C_5)$ and prove that for
any positive integer $p$ and sufficiently large $n$, there exists a constant
$c=c(p)$ such that the following holds: if $ex_p(n, C_5)=e_p(G)$ for some
$C_5$-free graph $G$ of order $n$, then $G$ is a complete bipartite graph
having one vertex class of size $cn+o(n)$ and the other $(1-c)n+o(n)$.


title: The Dirichlet problem for p-harmonic functions on the topologist's comb

abstract:
  In this paper we study the Perron method for solving the p-harmonic Dirichlet
problem on the topologist's comb. For functions which are bounded and
continuous at the accessible points, we obtain invariance of the Perron
solutions under arbitrary perturbations on the set of inaccessible points. We
also obtain some results allowing for jumps and perturbations at a countable
set of points.


title: The Complexity of Admissibility in Omega-Regular Games

abstract:
  Iterated admissibility is a well-known and important concept in classical
game theory, e.g. to determine rational behaviors in multi-player matrix games.
As recently shown by Berwanger, this concept can be soundly extended to
infinite games played on graphs with omega-regular objectives. In this paper,
we study the algorithmic properties of this concept for such games. We settle
the exact complexity of natural decision problems on the set of strategies that
survive iterated elimination of dominated strategies. As a byproduct of our
construction, we obtain automata which recognize all the possible outcomes of
such strategies.


title: Data Hiding in Binary Image using Block Parity

abstract:
  Secret data hiding in binary images is more difficult than other formats
since binary images require only one bit representation to indicate black and
white. This study proposes a new method for data hiding in binary images using
optimized bit position to replace a secret bit. This method manipulates blocks,
which are sub-divided. The parity bit for a specified block decides whether to
change or not, to embed a secret bit. By finding the best position to insert a
secret bit for each divided block, the image quality of the resulting
stego-image can be improved, while maintaining low computational complexity.The
experimental results show that the proposed method has an improvement with
respect to a previous work.


title: Probability Aggregates in Probability Answer Set Programming

abstract:
  Probability answer set programming is a declarative programming that has been
shown effective for representing and reasoning about a variety of probability
reasoning tasks. However, the lack of probability aggregates, e.g. {\em
expected values}, in the language of disjunctive hybrid probability logic
programs (DHPP) disallows the natural and concise representation of many
interesting problems. In this paper, we extend DHPP to allow arbitrary
probability aggregates. We introduce two types of probability aggregates; a
type that computes the expected value of a classical aggregate, e.g., the
expected value of the minimum, and a type that computes the probability of a
classical aggregate, e.g, the probability of sum of values. In addition, we
define a probability answer set semantics for DHPP with arbitrary probability
aggregates including monotone, antimonotone, and nonmonotone probability
aggregates. We show that the proposed probability answer set semantics of DHPP
subsumes both the original probability answer set semantics of DHPP and the
classical answer set semantics of classical disjunctive logic programs with
classical aggregates, and consequently subsumes the classical answer set
semantics of the original disjunctive logic programs. We show that the proposed
probability answer sets of DHPP with probability aggregates are minimal
probability models and hence incomparable, which is an important property for
nonmonotonic probability reasoning.


title:
Proposal for the detection and braiding of Majorana fermions in a
  quantum spin Hall insulator

abstract:
  We show how a quantum dot with a ballistic single-channel point contact to a
superconductor can be created by means of a gate electrode at the edge of a
quantum spin Hall insulator (such as an InAs/GaSb quantum well). A weak
perpendicular magnetic field traps a Majorana zero-mode, so that it can be
observed in the gate-voltage-averaged differential conductance <dI/dV> as a
4e^2/h zero-bias peak above a (2/3{\pi}^2 - 4)e^2/h background. The
one-dimensional edge does not permit the braiding of pairs of Majorana
fermions, but this obstacle can be overcome by coupling opposite edges at a
constriction, allowing for a demonstration of non-Abelian statistics.