title:
Maximal Syntactic Complexity of Regular Languages Implies Maximal
  Quotient Complexities of Atoms

abstract:
  We relate two measures of complexity of regular languages. The first is
syntactic complexity, that is, the cardinality of the syntactic semigroup of
the language. That semigroup is isomorphic to the semigroup of transformations
of states induced by non-empty words in the minimal deterministic finite
automaton accepting the language. If the language has n left quotients (its
minimal automaton has n states), then its syntactic complexity is at most n^n
and this bound is tight. The second measure consists of the quotient (state)
complexities of the atoms of the language, where atoms are non-empty
intersections of complemented and uncomplemented quotients. A regular language
has at most 2^n atoms and this bound is tight. The maximal quotient complexity
of any atom with r complemented quotients is 2^n-1, if r=0 or r=n, and
1+\sum_{k=1}^{r} \sum_{h=k+1}^{k+n-r} \binom{h}{n} \binom{k}{h}, otherwise. We
prove that if a language has maximal syntactic complexity, then it has 2^n
atoms and each atom has maximal quotient complexity, but the converse is false.


title:
Record Maximum Oscillation Frequency in C-face Epitaxial Graphene
  Transistors

abstract:
  The maximum oscillation frequency (fmax) quantifies the practical upper bound
for useful circuit operation. We report here an fmax of 70 GHz in transistors
using epitaxial graphene grown on the C-face of SiC. This is a significant
improvement over Si-face epitaxial graphene used in the prior high frequency
transistor studies, exemplifying the superior electronics potential of C-face
epitaxial graphene. Careful transistor design using a high {\kappa} dielectric
T-gate and self-aligned contacts, further contributed to the record-breaking
fmax.


title: Weak Z-structures for some classes of groups

abstract:
  Motivated by the usefulness of boundaries in the study of hyperbolic and
CAT(0) groups, Bestvina introduced a general approach to group boundaries via
the notion of a Z-structure on a group G. Several variations on Z-structures
have been studied and existence results have been obtained for some very
specific classes of groups. However, little is known about the general question
of which groups admit any of the various Z-structures, aside from the (easy)
fact that any such G must have type F, i.e., G must admit a finite K(G,1). In
fact, Bestvina has asked whether every type F group admits a Z-structure or at
least a "weak" Z-structure. In this paper we prove some rather general
existence theorems for weak Z-structures. Among our results are the following:
  Theorem A. If G is an extension of a nontrivial type F group by a nontrivial
type F group, then G admits a Z-structure.
  Theorem B. If G admits a finite K(G,1) complex K such that the corresponding
G-action on the universal cover contains a non-identity element properly
homotopic to the identity, then G admits a weak Z-structure.
  Theorem C. If G has type F and is simply connected at infinity, then G admits
a weak Z-structure.


title: BR(Bs to mu+ mu-) as an electroweak precision test

abstract:
  Using an effective-theory approach, we analyze the impact of BR(Bs to mu+
mu-) in constraining new-physics models that predict modifications of the
Z-boson couplings to down-type quarks. Under motivated assumptions about the
flavor structure of the effective theory, we show that the bounds presently
derived from BR(Bs to mu+ mu-) on the effective Z-boson couplings are
comparable (in the case of minimal flavor violation) or significantly more
stringent (in the case of generic partial compositeness) with respect to those
derived from observables at the Z peak.


title: Optimizing Doppler Surveys for Planet Yield

abstract:
  One of the most promising methods of discovering nearby, low-mass planets in
the habitable zones of stars is the precision radial velocity technique.
However, there are many challenges that must be overcome to efficiently detect
low-amplitude Doppler signals. This is both due to the required instrumental
sensitivity and the limited amount of observing time. In this paper, we examine
statistical and instrumental effects on precision radial velocity detection of
extrasolar planets, an approach by which we maximize the planet yield in a
fixed amount of observing time available on a given telescope. From this
perspective, we show that G and K dwarfs observed at 400-600 nm are the best
targets for surveys complete down to a given planet mass and out to a specified
orbital period. Overall we find that M dwarfs observed at 700-800 nm are the
best targets for habitable-zone planets, particularly when including the
effects of systematic noise floors. Also, we give quantitative specifications
of the instrumental stability necessary to achieve the required velocity
precision.


title:
Color transparency in the reaction nuclear rho production by virtual
  photons

abstract:
  We study the nuclear transparency $T$ for the exclusive reaction
$\gamma^*+A\to\rho+p+(A-1)^*$ at incident virtual photon energies $\nu \ge$ 10
GeV %where the final state of the $A-1$-nucleon system is a one-hole state of
the initial nucleus, to investigate the separate dependence on the photon
virtuality, $Q^2$ and the 4-momentum-transfer-squared to the knocked-out
proton, $t$. If the effects of color transparency are included, $T$ shows
significant variation with $t$ even for small values of $Q^2$ for fixed values
of the coherence length $l_c$, and also shows significant increase as $Q^2$ is
increased at fixed $l_c$ and $t$. The value of $T$ is found to depend strongly
on the phase space over which it is measured.


title:
An Online Environment for Democratic Deliberation: Motivations,
  Principles, and Design

abstract:
  We have created a platform for online deliberation called Deme (which rhymes
with 'team'). Deme is designed to allow groups of people to engage in
collaborative drafting, focused discussion, and decision making using the
Internet. The Deme project has evolved greatly from its beginning in 2003. This
chapter outlines the thinking behind Deme's initial design: our motivations for
creating it, the principles that guided its construction, and its most
important design features. The version of Deme described here was written in
PHP and was deployed in 2004 and used by several groups (including organizers
of the 2005 Online Deliberation Conference). Other papers describe later
developments in the Deme project (see Davies et al. 2005, 2008; Davies and
Mintz 2009).


title: Multiclass Data Segmentation using Diffuse Interface Methods on Graphs

abstract:
  We present two graph-based algorithms for multiclass segmentation of
high-dimensional data. The algorithms use a diffuse interface model based on
the Ginzburg-Landau functional, related to total variation compressed sensing
and image processing. A multiclass extension is introduced using the Gibbs
simplex, with the functional's double-well potential modified to handle the
multiclass case. The first algorithm minimizes the functional using a convex
splitting numerical scheme. The second algorithm is a uses a graph adaptation
of the classical numerical Merriman-Bence-Osher (MBO) scheme, which alternates
between diffusion and thresholding. We demonstrate the performance of both
algorithms experimentally on synthetic data, grayscale and color images, and
several benchmark data sets such as MNIST, COIL and WebKB. We also make use of
fast numerical solvers for finding the eigenvectors and eigenvalues of the
graph Laplacian, and take advantage of the sparsity of the matrix. Experiments
indicate that the results are competitive with or better than the current
state-of-the-art multiclass segmentation algorithms.


title: Residual Stresses in Glasses

abstract:
  The history dependence of the glasses formed from flow-melted steady states
by a sudden cessation of the shear rate $\dot\gamma$ is studied in colloidal
suspensions, by molecular dynamics simulations, and mode-coupling theory. In an
ideal glass, stresses relax only partially, leaving behind a finite persistent
residual stress. For intermediate times, relaxation curves scale as a function
of $\dot\gamma t$, even though no flow is present. The macroscopic stress
evolution is connected to a length scale of residual liquefaction displayed by
microscopic mean-squared displacements. The theory describes this history
dependence of glasses sharing the same thermodynamic state variables, but
differing static properties.


title:
Detecting Long-Duration Narrow-Band Gravitational Wave Transients
  Associated with Soft Gamma Repeater Quasi-Periodic Oscillations

abstract:
  We have performed an in-depth concept study of a gravitational wave data
analysis method which targets repeated long quasi-monochromatic transients
(triggers) from cosmic sources. The algorithm concept can be applied to
multi-trigger data sets in which the detector-source orientation and the
statistical properties of the data stream change with time, and does not
require the assumption that the data is Gaussian. Reconstructing or limiting
the energetics of potential gravitational wave emissions associated with
quasi-periodic oscillations (QPOs) observed in the X-ray lightcurve tails of
soft gamma repeater flares might be an interesting endeavour of the future.
Therefore we chose this in a simplified form to illustrate the flow,
capabilities, and performance of the method. We investigate performance aspects
of a multi-trigger based data analysis approach by using O(100 s) long
stretches of mock data in coincidence with the times of observed QPOs, and by
using the known sky location of the source. We analytically derive the PDF of
the background distribution and compare to the results obtained by applying the
concept to simulated Gaussian noise, as well as off-source playground data
collected by the 4-km Hanford detector (H1) during LIGO's fifth science run
(S5). We show that the transient glitch rejection and adaptive differential
energy comparison methods we apply succeed in rejecting outliers in the S5
background data. Finally, we discuss how to extend the method to a network
containing multiple detectors, and as an example, tune the method to maximize
sensitivity to SGR 1806-20 flare times.


title:
Rotational quenching of rotationally-excited H$_2$O in collisions with
  He

abstract:
  Theoretical rotational quenching cross sections and rate coefficients of
ortho- and para-H$_2$O due to collisions with He atoms are presented. The
complete angular momentum close-coupling approach as well as the coupled-states
approximation for angular momentum decoupling were applied to solve the
scattering problem for a large range of rotationally-excited states of water.
Results are obtained for quenching from initial levels 1$_{1,0}$, 2$_{1,2}$,
2$_{2,1}$, 3$_{0,3}$, 3$_{1,2}$, 3$_{2,1}$, 4$_{1,4}$, 3$_{3,0}$, and 4$_{2,3}$
of ortho-H$_2$O and from initial levels 1$_{1,1}$, 2$_{0,2}$, 2$_{1,1}$,
2$_{2,0}$, 3$_{1,3}$, 3$_{2,2}$, 4$_{0,4}$, 4$_{1,3}$, and 3$_{3,1}$ of
para-H$_2$O for kinetic energies from 10$^{-5}$ to 10$^4$ cm$^{-1}$.
State-to-state and total deexcitation cross sections and rate coefficients for
temperatures between 0.1 and 3000 K are reported. The present state-to-state
rate coefficients are found to be in good agreement with previous results
obtained by Green and coworkers at high temperatures, but significant
discrepancies are obtained at lower temperatures likely due to differences in
the adopted potential energy surfaces. Astrophysical applications of the
current rate coefficients are briefly discussed.


title: k-d Darts: Sampling by k-Dimensional Flat Searches

abstract:
  We formalize the notion of sampling a function using k-d darts. A k-d dart is
a set of independent, mutually orthogonal, k-dimensional subspaces called k-d
flats. Each dart has d choose k flats, aligned with the coordinate axes for
efficiency. We show that k-d darts are useful for exploring a function's
properties, such as estimating its integral, or finding an exemplar above a
threshold. We describe a recipe for converting an algorithm from point sampling
to k-d dart sampling, assuming the function can be evaluated along a k-d flat.
  We demonstrate that k-d darts are more efficient than point-wise samples in
high dimensions, depending on the characteristics of the sampling domain: e.g.
the subregion of interest has small volume and evaluating the function along a
flat is not too expensive. We present three concrete applications using line
darts (1-d darts): relaxed maximal Poisson-disk sampling, high-quality
rasterization of depth-of-field blur, and estimation of the probability of
failure from a response surface for uncertainty quantification. In these
applications, line darts achieve the same fidelity output as point darts in
less time. We also demonstrate the accuracy of higher dimensional darts for a
volume estimation problem. For Poisson-disk sampling, we use significantly less
memory, enabling the generation of larger point clouds in higher dimensions.


title: Using Correlated Subset Structure for Compressive Sensing Recovery

abstract:
  Compressive sensing is a methodology for the reconstruction of sparse or
compressible signals using far fewer samples than required by the Nyquist
criterion. However, many of the results in compressive sensing concern random
sampling matrices such as Gaussian and Bernoulli matrices. In common physically
feasible signal acquisition and reconstruction scenarios such as
super-resolution of images, the sensing matrix has a non-random structure with
highly correlated columns. Here we present a compressive sensing recovery
algorithm that exploits this correlation structure. We provide algorithmic
justification as well as empirical comparisons.


title:
Derivation of an EM algorithm for constrained and unconstrained
  multivariate autoregressive state-space (MARSS) models

abstract:
  This report presents an Expectation-Maximization (EM) algorithm for
estimation of the maximum-likelihood parameter values of constrained
multivariate autoregressive Gaussian state-space (MARSS) models. The MARSS
model can be written: x(t)=Bx(t-1)+u+w(t), y(t)=Zx(t)+a+v(t), where w(t) and
v(t) are multivariate normal error-terms with variance-covariance matrices Q
and R respectively. MARSS models are a class of dynamic linear model and vector
autoregressive state-space model. Shumway and Stoffer presented an
unconstrained EM algorithm for this class of models in 1982, and a number of
researchers have presented EM algorithms for specific types of constrained
MARSS models since then. In this report, I present a general EM algorithm for
constrained MARSS models, where the constraints are on the elements within the
parameter matrices (B,u,Q,Z,a,R). The constraints take the form vec(M)=f+Dm,
where M is the parameter matrix, f is a column vector of fixed values, D is a
matrix of multipliers, and m is the column vector of estimated values. This
allows a wide variety of constrained parameter matrix forms. The presentation
is for a time-varying MARSS model, where time-variation enters through the
fixed (meaning not estimated) f(t) and D(t) matrices for each parameter. The
algorithm allows missing values in y and partially deterministic systems where
0s appear on the diagonals of Q or R. Open source code for estimating MARSS
models with this algorithm is provided in the MARSS R package on the
Comprehensive R Archive Network (CRAN).


title:
Ellipsoids and elliptic hyperboloids in the Euclidean space ${\Bbb
  E}^{n+1}$

abstract:
  We establish some characterizations of elliptic hyperboloids (resp.,
ellipsoids) in the $(n+1)$-dimensional Euclidean space
  ${\Bbb E}^{n+1}$, using the $n$-dimensional area of the sections cut off by
hyperplanes and the $(n+1)$-dimensional volume of regions between parallel
hyperplanes. We also give a few characterizations of elliptic paraboloids in
the $(n+1)$-dimensional Euclidean space
  ${\Bbb E}^{n+1}$.


title: Support detection in super-resolution

abstract:
  We study the problem of super-resolving a superposition of point sources from
noisy low-pass data with a cut-off frequency f. Solving a tractable convex
program is shown to locate the elements of the support with high precision as
long as they are separated by 2/f and the noise level is small with respect to
the amplitude of the signal.


title:
Variability Effects in Graphene: Challenges and Opportunities for Device
  Engineering and Applications

abstract:
  Variability effects in graphene can result from the surrounding environment
and the graphene material itself, which form a critical issue in examining the
feasibility of graphene devices for large-scale production. From the
reliability and yield perspective, these variabilities cause fluctuations in
the device performance, which should be minimized via device engineering. From
the metrology perspective, however, the variability effects can function as
novel probing mechanisms, in which the 'signal fluctuations' can be useful for
potential sensing applications. This paper presents an overview of the
variability effects in graphene, with emphasis on their challenges and
opportunities for device engineering and applications. The discussion can
extend to other thin-film, nanowire and nanotube devices with similar
variability issues, forming general interest in evaluating the promise of
emerging technologies.


title: A complicated Duffing oscillator in the surface-electrode ion trap

abstract:
  The oscillation coupling and different nonlinear effects are observed in a
single trapped $^{40}Ca^{+}$ ion confined in our home-built surface-electrode
trap (SET). The coupling and the nonlinearity are originated from the
high-order multipole potentials due to different layouts and the fabrication
asymmetry of the SET. We solve a complicated Duffing equation with coupled
oscillation terms by the multiple scale method, which fits the experimental
values very well. Our investigation in the SET helps for exploring nonlinearity
using currently available techniques and for suppressing instability of qubits
in quantum information processing with trapped ions.


title:
Stochastic determination of effective Hamiltonian for the full
  configuration interaction solution of quasi-degenerate electronic states

abstract:
  We propose a novel quantum Monte Carlo method in configuration space, which
stochastically samples the contribution from a large secondary space to the
effective Hamiltonian in the energy dependent partitioning of L\"owdin. The
method treats quasi-degenerate electronic states on a target energy with bond
dissociations and electronic excitations avoiding significant amount of the
negative sign problem. The performance is tested with small model systems of
H$_4$ and N$_2$ at various configurations with quasi-degeneracy.


title: Cuboidal Dice and Gibbs Distributions

abstract:
  What are the face-probabilities of a cuboidal die, i.e. a die with different
side-lengths? This paper introduces a model for these probabilities based on a
Gibbs distribution. Experimental data produced in this work and drawn from the
literature support the Gibbs model. The experiments also reveal that the
physical conditions, such as the quality of the surface onto which the dice are
dropped, can affect the face-probabilities. In the Gibbs model, those
variations are condensed in a single parameter, adjustable to the physical
conditions.


title: Rationality of Euler-Chow series and finite generation of Cox rings

abstract:
  In this paper we work with a series whose coefficients are the Euler
characteristic of Chow varieties of a given projective variety. For varieties
where the Cox ring is defined, it is easy to see that in this case the ring
associated to the series is the Cox ring. If this ring is noetherian then the
series is rational. It is an open question whether the converse holds. In this
paper we give an example showing the converse fails. However we conjecture that
it holds when the variety is rationally connected. As an evidence of this
conjecture, It is proved that the series is not rational, and in a sense
defined, not algebraic, in the case of the blowup of the projective plane at
nine or more points in general position. Furthermore, we also treat some other
examples of varieties with infinitely generated Cox ring, studied by Mukai and
Hassett-Tschinkel. These are the first examples known where the series is not
rational. We also compute the series for Del Pezzo surfaces.


title:
The automatic additivity of $\xi-$Lie derivations on von Neumann
  algebras

abstract:
  Let ${\mathcal M}$ be a von Neumann algebra with no central summands of type
I$_1$. It is shown that every nonlinear $\xi-$Lie derivation ($\xi\neq 1$) on
$\mathcal M$ is an additive derivation.


title: Fluorine Abundances of Galactic Low-Metallicity Giants

abstract:
  With abundances and 2{\sigma} upper limits of fluorine (F) in seven
metal-poor field giants, nucleosynthesis of stellar F at low metallicity is
discussed. The measurements are derived from the HF(1-0) R9 line at 23358{\AA}
using nearinfrared K-band high-resolution spectra obtained with CRIRES at the
Very Large Telescope. The sample reaches lower metallicities than previous
studies on F of field giants, ranging from [Fe/H] = -1.56 down to -2.13.
Effects of three-dimensional model atmospheres on the derived F and O
abundances are quantitatively estimated and shown to be insignificant for the
program stars. The observed F yield in the form of [F/O] is compared with two
sets of Galactic chemical evolution models, which quantitatively demonstrate
the contribution of Type II supernova (SN II) {\nu}-process and asymptotic
giant branch/Wolf-Rayet stars. It is found that at this low-metallicity region,
models cannot well predict the observed distribution of [F/O], while the
observations are better fit by models considering an SN II {\nu}-process with a
neutrino energy of E_{\nu} = 3 x 10^53 erg. Our sample contains HD 110281, a
retrograde orbiting low-{\alpha} halo star, showing a similar F evolution as
globular clusters. This supports the theory that such halo stars are possibly
accreted from dwarf galaxy progenitors of globular clusters in the halo.


title: Admissions Criteria and Diversity in Graduate School

abstract:
  In this work, I point out the negative implications for diversity in graduate
school resulting from the use of cutoff scores on the GRE in the admissions
process. In light of the data presented, as well as a swelling body of evidence
suggesting no long term correlation with research success, I pose several
challenges to the community related to the continued use of the GRE.


title:
Complete Glauber calculations of reaction and interaction cross sections
  in light ion collisions

abstract:
  We calculate the differences between reaction and interaction cross sections
in the collisions of relativistic light ions with $\text{A}<40$ in the
framework of Glauber theory. Although, in the optical approximation of Glauber
theory these differences are approximately 1% of the reaction cross sections or
less, they increase up to 3-4% when all scattering diagrams of Glauber theory
are included in calculation.


title:
Understanding Boltzmann Machine and Deep Learning via A Confident
  Information First Principle

abstract:
  Typical dimensionality reduction methods focus on directly reducing the
number of random variables while retaining maximal variations in the data. In
this paper, we consider the dimensionality reduction in parameter spaces of
binary multivariate distributions. We propose a general
Confident-Information-First (CIF) principle to maximally preserve parameters
with confident estimates and rule out unreliable or noisy parameters. Formally,
the confidence of a parameter can be assessed by its Fisher information, which
establishes a connection with the inverse variance of any unbiased estimate for
the parameter via the Cram\'{e}r-Rao bound. We then revisit Boltzmann machines
(BM) and theoretically show that both single-layer BM without hidden units
(SBM) and restricted BM (RBM) can be solidly derived using the CIF principle.
This can not only help us uncover and formalize the essential parts of the
target density that SBM and RBM capture, but also suggest that the deep neural
network consisting of several layers of RBM can be seen as the layer-wise
application of CIF. Guided by the theoretical analysis, we develop a
sample-specific CIF-based contrastive divergence (CD-CIF) algorithm for SBM and
a CIF-based iterative projection procedure (IP) for RBM. Both CD-CIF and IP are
studied in a series of density estimation experiments.


title:
Real-Time Power Balancing via Decentralized Coordinated Home Energy
  Scheduling

abstract:
  It is anticipated that an uncoordinated operation of individual home energy
management (HEM) systems in a neighborhood would have a rebound effect on the
aggregate demand profile. To address this issue, this paper proposes a
coordinated home energy management (CoHEM) architecture in which distributed
HEM units collaborate with each other in order to keep the demand and supply
balanced in their neighborhood. Assuming the energy requests by customers are
random in time, we formulate the proposed CoHEM design as a multi-stage
stochastic optimization problem. We propose novel models to describe the
deferrable appliance load (e.g., Plug-in (Hybrid) Electric Vehicles (PHEV)),
and apply approximation and decomposition techniques to handle the considered
design problem in a decentralized fashion. The developed decentralized CoHEM
algorithm allow the customers to locally compute their scheduling solutions
using domestic user information and with message exchange between their
neighbors only. Extensive simulation results demonstrate that the proposed
CoHEM architecture can effectively improve real-time power balancing.
Extensions to joint power procurement and real-time CoHEM scheduling are also
presented.


title: The Weak Finitistic Dimension of a Path Algebra is Finite

abstract:
  We prove a version of Bass' finitistic dimension conjecture for path algebras
over arbitrary directed graphs. It is known that the path algebra of a finite
directed graph is hereditary, hence it has finite finitistic dimension, when
the graph is acyclic. The case for arbitrary directed graphs is still open. We
use flat dimension instead of projective dimension (hence the designation
"weak") and show that the weak finitistic dimension of an arbitrary path
algebra is finite.


title:
Myoelectric Control of Artificial Limb Inspired by Quantum Information
  Processing

abstract:
  Precise and elegant coordination of a prosthesis across many degrees of
freedom represents a significant challenge to efficient rehabilitation of
people with limb deficiency. Processing the electrical neural signals,
collected from the surface of the remnant muscles of the stump, is a common way
to initiate and control the different movements available to the artificial
limb. Based on the assumption that there are distinguishable and repeatable
signal patterns among different types of muscular activation, the problem of
the prosthesis control reduces to one of pattern recognition. Widely accepted
classical methods for pattern recognition, however, cannot provide simultaneous
and proportional control of the artificial limb. Here we show that, in
principle, quantum information processing of the neural signals allows us to
overcome the above-mentioned difficulties suggesting a very simple scheme for
myoelectric control of artificial limb with advanced functionalities.


title: Second harmonic microscopy of monolayer MoS2

abstract:
  We show that the lack of inversion symmetry in monolayer MoS2 allows strong
optical second harmonic generation. Second harmonic of an 810-nm pulse is
generated in a mechanically exfoliated monolayer, with a nonlinear
susceptibility on the order of 1E-7 m/V. The susceptibility reduces by a factor
of seven in trilayers, and by about two orders of magnitude in even layers. A
proof-of-principle second harmonic microscopy measurement is performed on
samples grown by chemical vapor deposition, which illustrates potential
applications of this effect in fast and non-invasive detection of crystalline
orientation, thickness uniformity, layer stacking, and single-crystal domain
size of atomically thin films of MoS2 and similar materials.


title:
Two-loop radiative seesaw with multicomponent dark matter explaining the
  possible gamma excess in the Higgs boson decay and at the Fermi LAT

abstract:
  A non-supersymmetric model of a two-loop radiative seesaw is proposed. The
model contains, in addition to the standard model (SM) Higgs boson, an inert
SU(2)_L doublet scalar eta and two inert singlet scalars phi and chi. The
lepton number is softly broken by a dimension-two operator, and the tree-level
Dirac mass is forbidden by Z_2 x Z_2' (or D_{2N}), which predicts the existence
of two or three dark matter particles. The scalar sector is minimal; none of
the scalar fields can be suppressed for the radiative seesaw mechanism to work.
There are by-products: The SM Higgs boson decay into two gamma's is slightly
enhanced by eta^+ (the charged component of eta) circulating in one-loop
diagrams for h to gamma gamma. The 135 GeV gamma-ray line observed at the Fermi
LAT can be also explained by the annihilation of chi dark matter. We employ a
mechanism of temperature-dependent annihilation cross section to suppress the
continuum gamma rays and the production of antiprotons. The explanation can
survive even down to the XENON1T sensitivity limit.


title:
Metal - non-metal transition and the second critical point in expanded
  metals

abstract:
  Based on the non-relativistic Coulomb model within which the matter is a
system of interacting electrons and nuclei, using the quantum field theory and
linear response theory methods, opportunity for the existence of the second
critical point in expanded metals, which is directly related to the
metal--nonmetal transition, predicted by Landau and Zeldovitch, is
theoretically justified. It is shown that the matter at the second critical
point is in the state of true dielectric with zero static conductivity. The
results obtained are in agreement with recent experiments for expanded metals.
The existence of the second critical point is caused by the initial
multi-component nature of the matter consisting of electrons and nuclei and the
long-range character of the Coulomb interaction. (Accepted in PTEP)


title:
SED-inferred properties and morphology of Lyman-break galaxies at $z\sim
  1$ in the CDF-S

abstract:
  After carefully cross-identifying a previously discovered GALEX-selected
Lyman Break Galaxy (LBG) candidates one-to-one with their optical counterparts
in the field of the CDF-S, we re-estimate their photometric redshifts using
multi-wavelength data from UV, optical to NIR. We refine a new updated sample
of 383 LBGs at $0.7\la z \la 1.4$.
  Most LBGs are classified as starburst and irregular types. Ages spread from
several Myr to 1.5Gyr. Their dust-corrected star formation rates (SFRs) and
stellar masses ($M_*$) are from $4\my$ to $220\my$ and from $2.3\times 10^8
\msun$ to $4 \times 10^{11} \msun$. The rest-frame FUV luminosity function of
LBGs are presented. LBGs of irregular types mainly distribute along the "main
sequence" of star forming galaxies while most LBGs of starburst types locate in
the starburst region. A "downsizing" effect is clearly found and LBGs
distribute in the "blue" cloud.
  HST images in F606W ($V$ band) and F850LP ($z$ band) are taken from the GEMS
and GOODS-S surveys. SExtractor and GALFIT are applied to get their
morphological parameters. A morphological sample of 142 LBGs with reliable
results of $\sersic$ and sizes in both bands is defined. We find that LBGs at
$z\sim 1 $ are dominated by disk-like galaxies. Correlations between
photometric and morphological properties of LBGs are investigated. Strong
correlations between their half-light radii and $M_*$, i.e., size-stellar mass
relations, are found in both bands. Physical connections between correlations
and the "downsizing" effect are discussed.


title:
Note on an application of the method of uniqueness to reduced quantum
  electrodynamics

abstract:
  Using the method of uniqueness a two-loop massless propagator Feynman diagram
with a non-integer index on the central line is evaluated in a very transparent
way. The result is applied to the computation of the two-loop polarization
operator in reduced quantum electrodynamics.


title: On the flips for a synchronized system

abstract:
  It is shown that if an infinite synchronized system has a flip, then it has
infinitely many non-conjugate flips, and that the result cannot be extended to
the class of coded systems.


title:
Unveiling the detailed density and velocity structures of the
  protostellar core B335

abstract:
  We present an observational study of the protostellar core B335 harboring a
low-mass Class 0 source. The observations of the H13CO+(J=1-0) line emission
were carried out using the Nobeyama 45 m telescope and Nobeyama Millimeter
Array. Our combined image of the interferometer and single-dish data depicts
detailed structures of the dense envelope within the core. We found that the
core has a radial density profile of n(r) prop. r^-p and a reliable difference
in the power-law indices between the outer and inner regions of the core: p~2
for r >= 4000 AU and p ~ 1.5 for r <= 4000 AU}. The dense core shows a slight
overall velocity gradient of ~1.0 km s^-1 over the scale of 20,000 AU across
the outflow axis. We believe that this velocity gradient represents a
solid-body-like rotation of the core. The dense envelope has a quite
symmetrical velocity structure with a remarkable line broadening toward the
core center, which is especially prominent in the position-velocity diagram
across the outflow axis. The model calculations of position-velocity diagrams
do a good job of reproducing observational results using the collapse model of
an isothermal sphere in which the core has an inner free-fall region and an
outer region conserving the conditions at the formation stage of a central
stellar object. We derived a central stellar mass of ~0.1 M_sun, and suggest a
small inward velocity, v(r>r_inf) ~ 0 km s^-1 in the outer core at >= 4000 AU.
We concluded that our data can be well explained by gravitational collapse with
a quasi-static initial condition, such as Shu's model, or by the isothermal
collapse of a marginally critical Bonnor-Ebert sphere.


title: Unipolar Vertical Transport in GaN/AlGaN/GaN Heterostructures

abstract:
  In this letter, we report on unipolar vertical transport characteristics in
c-plane GaN/AlGaN/GaN heterostructures. Vertical current in heterostructures
with random alloy barriers was found to be independent of dislocation density
and heterostructure barrier height, and significantly higher than theoretical
estimates. Percolation-based transport due to random alloy fluctuations in the
ternary AlGaN is suggested as the dominant transport mechanism, and confirmed
through experiments showing that non-random or digital AlGaN alloys and
polarization-engineered binary GaN barriers can eliminate percolation transport
and reduce leakage significantly. The understanding of vertical transport and
methods for effective control proposed here will greatly impact III-nitride
unipolar vertical devices.


title: Interplay between Network Topology and Dynamics in Neural Systems

abstract:
  This thesis is a compendium of research which brings together ideas from the
fields of Complex Networks and Computational Neuroscience to address two
questions regarding neural systems:
  1) How the activity of neurons, via synaptic changes, can shape the topology
of the network they form part of, and
  2) How the resulting network structure, in its turn, might condition aspects
of brain behaviour.
  Although the emphasis is on neural networks, several theoretical findings
which are relevant for complex networks in general are presented -- such as a
method for studying network evolution as a stochastic process, or a theory that
allows for ensembles of correlated networks, and sets of dynamical elements
thereon, to be treated mathematically and computationally in a
model-independent manner. Some of the results are used to explain experimental
data -- certain properties of brain tissue, the spontaneous emergence of
correlations in all kinds of networks... -- and predictions regarding
statistical aspects of the central nervous system are made. The mechanism of
Cluster Reverberation is proposed to account for the near-instant storage of
novel information the brain is capable of.

categories: q-bio.NC cond-mat.dis-nn nlin.AO physics.bio-ph


title:
Conformation-dependent electron transport through a biphenyl molecule:
  Circular current and related issues

abstract:
  We investigate the conformation-dependent electron transfer in a biphenyl
molecule within a simple tight-binding framework. The overall junction current
and circular currents in two benzene rings driven by applied bias voltage are
calculated by using Green's function formalism. Our analysis may provide the
possibilities of using organic molecules with loop substructures to design
molecular spintronic devices, indicating the emergence of molecular
spintronics.


title:
Electronic transport through a correlated quantum wire connected to a
  superconducting lead

abstract:
  We study theoretically the electron transport in a 1D conductor adiabatically
connected to a superconducting and normal metal leads. In the case of
non-interacting we show that ac voltage applied along with dc voltage modifies
I-V curve resembling a regime of photon-assisted tunneling. We obtain in the
limit of low voltages, that the electron-electron interaction affects
electronic transport resulting in a decrease of conductance and features in the
frequency dependence of the impedance.


title:
Approximating the optimal competitive ratio for an ancient online
  scheduling problem

abstract:
  We consider the classical online scheduling problem P||C_{max} in which jobs
are released over list and provide a nearly optimal online algorithm. More
precisely, an online algorithm whose competitive ratio is at most (1+\epsilon)
times that of an optimal online algorithm could be achieved in polynomial time,
where m, the number of machines, is a part of the input. It substantially
improves upon the previous results by almost closing the gap between the
currently best known lower bound of 1.88 (Rudin, Ph.D thesis, 2001) and the
best known upper bound of 1.92 (Fleischer, Wahl, Journal of Scheduling, 2000).
It has been known by folklore that an online problem could be viewed as a game
between an adversary and the online player. Our approach extensively explores
such a structure and builds up a completely new framework to show that, for the
online over list scheduling problem, given any \epsilon>0, there exists a
uniform threshold K which is polynomial in m such that if the competitive ratio
of an online algorithm is \rho<=2, then there exists a list of at most K jobs
to enforce the online algorithm to achieve a competitive ratio of at least
\rho-O(\epsilon). Our approach is substantially different from that of Gunther
et al. (Gunther et al., SODA 2013), in which an approximation scheme for online
over time scheduling problems is given, where the number of machines is fixed.
Our method could also be extended to several related online over list
scheduling models.


title:
Proposal for Manipulation of Majorana Fermions in Nano-Patterned
  Semiconductor-Superconductor Heterostructure

abstract:
  We investigate a heterostructure system with a spin-orbit coupled
semiconductor sandwiched by an s-wave superconductor and a ferromagnetic
insulator, which supports Majorana fermions (MFs) at the superconducting vortex
cores. We propose a scheme of transporting and braiding the MFs, which only
requires application of point-like gate voltages in a system with nano-meter
patterns. By solving the time-dependent Bogoliubov-de Gennes equation
numerically, we monitor the time evolutions of MF wave-functions and show that
the braiding of MFs with non-Abelian statistics can be achieved by adiabatic
switching within several nano seconds.


title:
Stability results for doubly nonlinear differential inclusions by
  variational convergence

abstract:
  We present a stability result for a wide class doubly nonlinear equations,
featuring general maximal monotone operators, and (possibly) nonconvex and
nonsmooth energy functionals. The limit analysis resides on the reformulation
of the differential evolution as a scalar energy-conservation equation with the
aid of the so-called Fitzpatrick theory for the representation of monotone
operators. In particular, our result applies to the vanishing viscosity
approximation of rate-independent systems.


title:
A collective opinion formation model under Bayesian updating and
  confirmation bias

abstract:
  We propose a collective opinion formation model with a so-called confirmation
bias. The confirmation bias is a psychological effect with which, in the
context of opinion formation, an individual in favor of an opinion is prone to
misperceive new incoming information as supporting the current belief of the
individual. Our model modifies a Bayesian decision-making model for single
individuals [M. Rabin and J. L. Schrag, Q. J. Econ. 114, 37 (1999)] for the
case of a well-mixed population of interacting individuals in the absence of
the external input. We numerically simulate the model to show that all the
agents eventually agree on one of the two opinions only when the confirmation
bias is weak. Otherwise, the stochastic population dynamics ends up creating a
disagreement configuration (also called polarization), particularly for large
system sizes. A strong confirmation bias allows various final disagreement
configurations with different fractions of the individuals in favor of the
opposite opinions.


title:
The paradox of soft singularity crossing avoided by distributional
  cosmological quantities

abstract:
  A flat Friedmann universe filled with a mixture of anti-Chaplygin gas and
dust-like matter evolves into a future soft singularity, where despite infinite
tidal forces the geodesics can be continued. In the singularity the pressure of
the anti-Chaplygin gas diverges, while its energy density is zero. The dust
energy density however does not vanish, neither does the Hubble parameter,
which implies further expansion, if its evolution is to be continuous. If so,
the energy density and the pressure of the anti-Chaplygin gas would become
ill-defined, hence only a contraction would be allowed. Paradoxically, the
universe in this cosmological model would have to expand and contract
simultaneously. The paradox can be avoided by redefining the anti-Chaplygin gas
in a distributional sense. Then the Hubble parameter could be mirrored to have
a jump at the singularity, allowing for a subsequent contraction. With this
modification the set of Friedmann, Raychaudhuri and continuity equations are
all obeyed both at the singularity and in its vicinity.


title: Quantum dynamics of a nano-rod under compression

abstract:
  A nano-rod under compression, which is capacitively coupled to a Cooper-pair
box, can be modeled in terms of a quartic oscillator linearly interacting with
a tunnelling pseudo-spin. We have integrated numerically the quantum dynamics
of this system in the partial Wigner representation and calculated the
pseudo-spin population difference. Depending on the coupling, we have verified
that the quantum tunnelling of the oscillator can lead to a more effective
reduction of the Rabi oscillation amplitude of the pseudo-spin. Such findings
suggests an experimental set-up that might be able to discriminate between the
quantum and the classical motion of a nano-rod.


title: The polarized Bjorken sum rule analysis: revised

abstract:
  We present progress in the QCD analysis of the Bjorken sum rule at low
momentum transfers. We study asymptotic structure of the perturbative QCD
expansion at low $Q^2$ scales based on analysis of recent accurate data on the
Bjorken sum rule and available now four-loop expression for the
coefficient-function $C_{Bj}(Q^2)$. We demonstrate that the standard
perturbative series for $C_{Bj}(Q^2)$ gives a hint to its asymptotic nature
manifesting itself in the region $Q^2 \lesssim 1$ GeV$^2$. It is confirmed by
the considered integral model for the perturbative QCD correction. We extract a
value of higher-twist $\mu_4$ coefficient and study the interplay between
higher orders and higher-twist contributions. Results of other approaches to
the description of Bjorken sum rule data are discussed.


title:
Comments on the Refractive Index of Tin Sulphide Nano-crystalline Thin
  Films

abstract:
  The refractive indices of nano-crystalline thin films of Tin (IV) Sulphide
(SnS) were investigated here. The experimental data conformed well with the
single oscillator model for refractive indices. Based on the this, we explain
the increasing trend of refractive index to the improvement in crystal ordering
with increasing grain size.


title: The formation of low-mass stars and brown dwarfs

abstract:
  It is estimated that ~60% of all stars (including brown dwarfs) have masses
below 0.2Msun. Currently, there is no consensus on how these objects form. I
will briefly review the four main theories for the formation of low-mass
objects: turbulent fragmentation, ejection of protostellar embryos, disc
fragmentation, and photo-erosion of prestellar cores. I will focus on the disc
fragmentation theory and discuss how it addresses critical observational
constraints, i.e. the low-mass initial mass function, the brown dwarf desert,
and the binary statistics of low-mass stars and brown dwarfs. I will examine
whether observations may be used to distinguish between different formation
mechanisms, and give a few examples of systems that strongly favour a specific
formation scenario. Finally, I will argue that it is likely that all mechanisms
may play a role in low-mass star and brown dwarf formation.


title: The formation of planets by disc fragmentation

abstract:
  I discuss the role that disc fragmentation plays in the formation of gas
giant and terrestrial planets, and how this relates to the formation of brown
dwarfs and low-mass stars, and ultimately to the process of star formation.
Protostellar discs may fragment, if they are massive enough and can cool fast
enough, but most of the objects that form by fragmentation are brown dwarfs. It
may be possible that planets also form, if the mass growth of a proto-fragment
is stopped (e.g. if this fragment is ejected from the disc), or suppressed and
even reversed (e.g by tidal stripping). I will discuss if it is possible to
distinguish whether a planet has formed by disc fragmentation or core
accretion, and mention of a few examples of observed exoplanets that are
suggestive of formation by disc fragmentation .


title: Clustering validity based on the most similarity

abstract:
  One basic requirement of many studies is the necessity of classifying data.
Clustering is a proposed method for summarizing networks. Clustering methods
can be divided into two categories named model-based approaches and algorithmic
approaches. Since the most of clustering methods depend on their input
parameters, it is important to evaluate the result of a clustering algorithm
with its different input parameters, to choose the most appropriate one. There
are several clustering validity techniques based on inner density and outer
density of clusters that represent different metrics to choose the most
appropriate clustering independent of the input parameters. According to
dependency of previous methods on the input parameters, one challenge in facing
with large systems, is to complete data incrementally that effects on the final
choice of the most appropriate clustering. Those methods define the existence
of high intensity in a cluster, and low intensity among different clusters as
the measure of choosing the optimal clustering. This measure has a tremendous
problem, not availing all data at the first stage. In this paper, we introduce
an efficient measure in which maximum number of repetitions for various initial
values occurs.


title:
Event reconstruction techniques for the wide-angle air Cherenkov
  detector HiSCORE

abstract:
  Wide-angle, non-imaging air Cherenkov detectors provide a way to observe
cosmic gamma-rays which is complementary to observations by imaging Cherenkov
telescopes. Their particular strength lies in the multi-TeV to ultra high
energy range (E > 30 TeV), where large effective areas, yet small light
sensitive areas per detector station are needed. To exploit this potential to
full extent, a large station spacing is required to achieve a large effective
area at a reasonable effort. In such a detector, the low number of signals per
event, the absence of imaging information, and the poor signal to noise ratio
of Cherenkov light to night sky brightness pose considerable challenges for the
event reconstruction, especially the gamma hadron separation. The event
reconstruction presented in this paper has been developed for the wide-angle
detector HiSCORE, but the concepts may be applied more generically. It is
tested on simulated data in the 10 TeV to 5 PeV energy range. For the tests, a
regular grid of 22 x 22 detector stations with a spacing of 150 m is assumed,
covering an area of 10 km^2. The angular resolution of individual events is
found to be about 0.3 degree near the energy threshold, improving to below 0.1
degree at higher energies. The relative energy resolution is 20% at the
threshold and improves to 10% at higher energies. Several parameters for gamma
hadron separation are described. With a combination of these parameters, 80% to
90% of the hadronic background can be suppressed, while about 60% of the
gamma-ray events are retained. The point source sensitivity to gamma-ray
sources is estimated, with conservative assumptions, to be about 8 x 10^(-13)
erg / s / cm^2 at 100 TeV gamma-ray for a 10 km^2 array. With more optimistic
assumptions, and a 100 km^2 array, a sensitivity of about 1 x 10^(-13) erg / s
/ cm^2 can be achieved (at 100 TeV).


title: Cross-diffusion Modeling in Macroeconomics

abstract:
  This paper deals with the stability properties of a closed market, where
capital and labour force are acting like a predator-prey system in
population-dynamics. The spatial movement of the capital and labour force are
taken into account by cross-diffusion effect. First, we are showing two
possible ways for modeling this system in only one country's market (applying a
simple functional response and a Holling-type ratio-dependent response as
well), examining the conditions of their stability properties. We extend the
ratio-dependent model into two countries common market where two kind of
cross-diffusion effects are present, and find those additional conditions,
whose are necessary for the stability of the global common market besides the
stability of each countries local markets. Our four-dimensional model
highlights that a hectic movement of the capital toward labour force can cause
a Turing instability.


title:
Enhancement of photon intensity in forced coupled quantum wells inside a
  semiconductor microcavity

abstract:
  We study numerically the photon emission from a semiconductor microcavity
containing $N\ge 2$ quantum wells under the influence of a periodic external
forcing. The emission is determined by the interplay between external forcing
and internal interaction between the wells. While the external forcing
synchronizes the periodic motion, the internal interaction destroys it. The
nonlinear term of the Hamiltonian supports the synchronization. The numerical
results show a jump of the photon intensity to very large values at a certain
critical value of the external forcing when the number of quantum wells is not
too large. We discuss the dynamics of the system across this transition.


title:
Earth Inner Core Periodic Motion due to Pressure Difference Induced by
  Tidal Acceleration

abstract:
  The inner structure of the earth is still a topic of discussion. Seismic
measurements showed a structure of solid, liquid, solid which describes the
mantle, outer core and inner core with the inner core in the center. The
analysis of waveform doublets suggests now that the inner core is out of center
and even of faster rotation than the mantel and crust. From the sum of Buoyancy
and Gravity on the earth inner core, the position energy is plotted and
together with the tangential tidal acceleration, it is derived that Earth Inner
Core cannot be in a center position without additional force. The Earth Core
System is explained as Hydrodynamic Bearing. The tidal acceleration is
identified as the reason for the periodic motion of the inner core and certain
frequencies of nutation. The Eccentricities out of nutation due to the effects
from the sun and moon are calculated as an approximation.


title: Hardy Inequalities in General Domains

abstract:
  Key Words: Hardy inequalities, Sobolev inequalities, Morrey inequality,
distance function, mean curvature, best constants, semi-concavity, sets with
positive reach, mean convex sets, Cheeger constant, modulus of continuity


title:
Quantum Oscillations of the Metallic Triangular-lattice Antiferromagnet
  PdCrO2

abstract:
  We report the de Haas-van Alphen (dHvA) oscillations and first-principle
calculations for triangular antiferromagnet PdCrO2 showing unconventional
anomalous Hall effect (AHE). The dHvA oscillations in PdCrO2 reveal presence of
several 2 dimensional Fermi surfaces of smaller size than found in nonmagnetic
PdCoO2. This evidences Fermi surface reconstruction due to the non-collinear
120 antiferromagnetic ordering of the localized Cr, consistent with the first
principle calculations. The temperature dependence of dHvA oscillations shows
no signature of additional modification of Cr spin structure below TN.
Considering that the 120 helical ordering of Cr spins has a zero scalar spin
chirality, our results suggest that PdCrO2 is a rare example of the metallic
triangular antiferromagnets whose unconventional AHE can not be understood in
terms of the spin chirality mechanism.


title:
Classification Scheme for Kinetic Energy Operators with
  Position-Dependent Mass

abstract:
  In this paper we present a complete classification scheme for kinetic energy
operators (KEO's) describing a particle endowed with position-dependent mass
(PDM). We first present a generalized formulation of KEO's with PDM and show
that it is equivalent to three-parameter linear formulation. This reduces
further to two independent parameters under Hermiticity condition. Based on
this linear formulation we prove that, contrary to what was widely believed,
von Roos family is not the most general ordering. We found an entire new family
of Hermitian KEO's that does not fit into von Roos ordering. We were able to
construct all the Hermitian KEO's and classify them into two-parameter classes.
As one application, we solve the puzzling case of Yang and Yee KEO. We also
find, under certain conditions, some kind of duality between von Roos ordering
and one of the new classes.


title:
Efficient, Broadband and Robust Frequency Conversion by Fully Nonlinear
  Adiabatic Three Wave Mixing

abstract:
  A comprehensive physical model of adiabatic three wave mixing is developed
for the fully nonlinear regime, i.e. without making the undepleted pump
approximation. The conditions for adiabatic evolution are rigorously derived,
together with an estimate of the bandwidth of the process. Furthermore, these
processes are shown to be robust and efficient. Finally, numerical simulations
demonstrate adiabatic frequency conversion in a wide variety of physically
attainable configurations.


title:
Perturbation analysis of bounded homogeneous generalized inverses on
  Banach spaces

abstract:
  Let $X, Y$ be Banach spaces and $T : X \to Y$ be a bounded linear operator.
In this paper, we initiate the study of the perturbation problems for bounded
homogeneous generalized inverse $T^h$ and quasi--linear projector generalized
inverse $T^H$ of $T$. Some applications to the representations and
perturbations of the Moore--Penrose metric generalized inverse $T^M$ of $T$ are
also given. The obtained results in this paper extend some well--known results
for linear operator generalized inverses in this field.


title:
Effect of Temperature Wave on Diffusive Transport of Weakly-Soluble
  Substances in Liquid-Saturated Porous Media

abstract:
  We study the effect of surface temperature oscillations on diffusive
transport of solutes of weaklysoluble substances through liquid-saturated
porous media. Temperature wave induced by these oscillations and decaying deep
in the porous massif creates the solubility wave along with the corresponding
solute diffusion flux wave. When the non-dissolved fraction is immobilized in
pores---for gases the bubbles can be immobilized by the surface tension force,
for solids (e.g., limestone, gas-hydrates) the immobilization of non-dissolved
phase is obvious---the only remaining mechanisms of mass transport are related
to solute flux through liquid in pores. We evaluate analytically the generated
time-average mass flux for the case of medium everywhere littered with
non-dissolved phase and reveal the significant effect of the temperature wave
on the substance release from the massif and non-dissolved mass redistribution
within the massif. Analytical theory is validated with numerical calculations.


title: Interaction phenomena in graphene seen through quantum capacitance

abstract:
  Capacitance measurements provide a powerful means of probing the density of
states. The technique has proved particularly successful in studying 2D
electron systems, revealing a number of interesting many-body effects. Here, we
use large-area high-quality graphene capacitors to study behavior of the
density of states in this material in zero and high magnetic fields. Clear
renormalization of the linear spectrum due to electron-electron interactions is
observed in zero field. Quantizing fields lead to splitting of the spin- and
valley-degenerate Landau levels into quartets separated by interaction-enhanced
energy gaps. These many-body states exhibit negative compressibility but the
compressibility returns to positive in ultrahigh B. The reentrant behavior is
attributed to a competition between field-enhanced interactions and nascent
fractional states.


title:
Measurement of the X(3872) production cross section via decays to J/psi
  pi pi in pp collisions at sqrt(s) = 7 TeV

abstract:
  The production of the X(3872) is studied in pp collisions at sqrt(s) = 7 TeV,
using decays to J/psi pi pi, where the J/psi decays to two muons. The data were
recorded by the CMS experiment and correspond to an integrated luminosity of
4.8 inverse femtobarns. The measurements are performed in a kinematic range in
which the X(3872) candidates have a transverse momentum 10 < pt < 50 GeV and
rapidity abs(y) < 1.2. The ratio of the X(3872) and psi(2S) cross sections
times their branching fractions into J/psi pi pi is measured as a function of
pt. In addition, the fraction of X(3872) originating from B decays is
determined. From these measurements the prompt X(3872) differential cross
section times branching fraction as a function of pt is extracted. The pi pi
mass spectrum of the J/psi pi pi system in the X(3872) decays is also
investigated.


title:
Coordination Control of Heterogeneous Compounded-Order Multi-Agent
  Systems with Communication Delays

abstract:
  Since the complexity of the practical environment, many distributed networked
systems can not be illustrated with the integer-order dynamics and only be
described as the fractional-order dynamics. Suppose multi-agent systems will
show the individual diversity with difference agents, where the heterogeneous
(integer-order and fractional-order) dynamics are used to illustrate the agent
systems and compose integer-fractional compounded-order systems. Applying
Laplace transform and frequency domain theory of the fractional-order operator,
consensus of delayed multi-agent systems with directed weighted topologies is
studied. Since integer-order model is the special case of fractional-order
model, the results in this paper can be extend to the systems with
integer-order models. Finally, numerical examples are used to verify our
results.


title:
Quantum singularities in spherically symmetric, conformally static
  spacetimes

abstract:
  A definition of quantum singularity for the case of static spacetimes has
recently been extended to conformally static spacetimes. Here the theory behind
quantum singularities in conformally static spacetimes is reviewed, and then
applied to a class of spherically symmetric, conformally static spacetimes,
including as special cases those studied by Roberts, by Fonarev, and by Husain,
Martinez, and N\'u\~nez. We use solutions of the generally coupled, massless
Klein-Gordon equation as test fields. In this way we find the ranges of metric
parameters and coupling coefficients for which classical timelike singularities
in these spacetimes are healed quantum mechanically.


title:
Directed Information on Abstract Spaces: Properties and Variational
  Equalities

abstract:
  Directed information or its variants are utilized extensively in the
characterization of the capacity of channels with memory and feedback,
nonanticipative lossy data compression, and their generalizations to networks.
In this paper, we derive several functional and topological properties of
directed information for general abstract alphabets (complete separable metric
spaces) using the topology of weak convergence of probability measures. These
include convexity of the set of consistent distributions, which uniquely define
causally conditioned distributions, convexity and concavity of directed
information with respect to the sets of consistent distributions, weak
compactness of these sets of distributions, their joint distributions and their
marginals. Furthermore, we show lower semicontinuity of directed information,
and under certain conditions we also establish continuity of directed
information. Finally, we derive variational equalities for directed
information, including sequential versions. These may be viewed as the analogue
of the variational equalities of mutual information (utilized in Blahut-Arimoto
algorithm).
  In summary, we extend the basic functional and topological properties of
mutual information to directed information. These properties are discussed in
the context of extremum problems of directed information.


title:
Some Features of Raman Scattering by Molecules Adsorbed on Metal Crystal
  Faces and a Fine Light Structure

abstract:
  The paper analyzes some experiments on Raman scattering by molecules adsorbed
on the face (111) of silver monocrystals performed by A. Campion et al. From
the existence of the forbidden line of benzene, the conclusion about existence
of the surface field, caused by atomic structure of the surface is made. The
relatively large intensity of this line allows to make a conclusion about large
influence of the electromagnetic field spatial inhomogeneity in crystals on
their optical properties. The difference between this field and a regular plane
wave, which usually describes propagation of electromagnetic field in solids is
named as a fine light structure. The influence of this structure on optical
properties of solids is pointed out.


title: Infinite sequential Nash equilibrium

abstract:
  In game theory, the concept of Nash equilibrium reflects the collective
stability of some individual strategies chosen by selfish agents. The concept
pertains to different classes of games, e.g. the sequential games, where the
agents play in turn. Two existing results are relevant here: first, all finite
such games have a Nash equilibrium (w.r.t. some given preferences) iff all the
given preferences are acyclic; second, all infinite such games have a Nash
equilibrium, if they involve two agents who compete for victory and if the
actual plays making a given agent win (and the opponent lose) form a
quasi-Borel set. This article generalises these two results via a single
result. More generally, under the axiomatic of Zermelo-Fraenkel plus the axiom
of dependent choice (ZF+DC), it proves a transfer theorem for infinite
sequential games: if all two-agent win-lose games that are built using a
well-behaved class of sets have a Nash equilibrium, then all multi-agent
multi-outcome games that are built using the same well-behaved class of sets
have a Nash equilibrium, provided that the inverse relations of the agents'
preferences are strictly well-founded.


title: Subvarieties of the hyperelliptic moduli determined by group actions

abstract:
  Let $\mathcal H_g$ be the moduli space of genus $g$ hyperelliptic curves. In
this note, we study the locus $\mathcal L$ in $\mathcal H_g$ of curves
admitting a $G$-action of given ramification type $\sigma$ and inclusions
between such loci. For each genus we determine the list of all possible groups,
the inclusions among the loci, and the corresponding equations of the generic
curve in $\mathcal L$. The proof of the results is based solely on
representations of finite subgroups of $PGL_2 (\mathbb C)$ and the
Riemann-Hurwitz formula.


title:
Spectroscopy of New and Poorly Known Cataclysmic Variables in the Kepler
  Field

abstract:
  The NASA {\it Kepler} mission has been in science operation since May 2009
and is providing high precision, high cadence light curves of over 150,000
targets. Prior to launch, nine cataclysmic variables were known to lie within
{\it Kepler's} field of view. We present spectroscopy for seven systems, four
of which were newly discovered since launch. All of the stars presented herein
have been observed by, or are currently being observed by, the {\it Kepler}
space telescope. Three historic systems and one new candidate could not be
detected at their sky position and two candidates are called into question as
to their true identity.


title: Twisted bi-layer graphene: microscopic rainbows

abstract:
  Twisted bi-layer graphene (tBLG) has recently attracted interest due to the
peculiar electrical properties that arise from its random rotational
configurations. Our experiments on CVD-grown graphene from Cu foil and
transferred onto Si substrates, with an oxide layer of 100 nm, reveal
naturally-produced bi-layer graphene patches which present different
colorations when shined with white light. In particular yellow-, pink- and
blue- colored areas are evidenced. Combining optical microscopy, Raman
spectroscopy and transmission electron microscopy we have been able to assign
these colorations to ranges of rotational angles between the two graphene
layers. Optical contrast simulations have been carried out, proving that the
observation of the different colorations is due to the angle-dependent
electronic properties of tBLG combined with the reflection that results from
the layered structure tBLG / 100 nm-thick SiO2 / Si. Our results could lead the
way to an easy selective identification of bi-layer graphene merely through the
observation on an optical microscope.


title: Inflation in Higher Dimensional Gauss-Bonnet Cosmology

abstract:
  A Gauss-Bonnet term naturally appears in the action for gravity when one
considers the existence of space time with dimensions more than 1+3. A variety
of inflationary models can be obtained within such a framework, once the scale
factor for the hidden dimension(s) is not constrained to be the same as that of
the visible ones. In particular, the need for an adhoc inflaton field is
eliminated. The phase space has a rich structure with different types of
solutions, both stable and unstable. For a large class of solutions, the scale
factors rapidly approach an asymptotic exponential form. Furthermore,
sufficient inflation can be obtained for only a modest compression of the
hidden world, if the latter is of a sufficiently large dimension.


title:
Nuclear Symmetries of the similarity renormalization group for nuclear
  forces

abstract:
  We review the role played by long-distance symmetries within the context of
the similarity renormalization group approach. This is based on
phase-shift-preserving continuous unitary transformations that evolve
Hamiltonians with a cutoff on energy differences. We find that there is a
similarity cutoff of 3/fm for which almost perfect fulfillment of Wigner SU(4)
symmetry is found at the two body level. This suggests to look for similar
symmetry patterns for three- and four-body forces. We also analyze the impact
of potentials based on Chiral Perturbation Theory in Nuclear Structure
calculations.


title: Gaussian Process Vine Copulas for Multivariate Dependence

abstract:
  Copulas allow to learn marginal distributions separately from the
multivariate dependence structure (copula) that links them together into a
density function. Vine factorizations ease the learning of high-dimensional
copulas by constructing a hierarchy of conditional bivariate copulas. However,
to simplify inference, it is common to assume that each of these conditional
bivariate copulas is independent from its conditioning variables. In this
paper, we relax this assumption by discovering the latent functions that
specify the shape of a conditional copula given its conditioning variables We
learn these functions by following a Bayesian approach based on sparse Gaussian
processes with expectation propagation for scalable, approximate inference.
Experiments on real-world datasets show that, when modeling all conditional
dependencies, we obtain better estimates of the underlying copula of the data.


title:
Generalized quantum microcanonical ensemble from random matrix product
  states

abstract:
  We propose a tensor network algorithm for the efficient sampling of quantum
pure states belonging to a generalized microcanonical ensemble. The algorithm
consists in an adaptation of the power method to a recently introduced ensemble
of random matrix product states. The microcanonical ensemble that we consider
is characterized by the fact that the participating energy eigenstates are not
required to have identical statistical weight. To test the method we apply it
to the Heisenberg model with an external magnetic field, and we find that the
magnetization curves, due to the microcanonical constraint, are qualitatively
different from those obtained in the canonical ensemble. Possible future
applications include the study of isolated quantum systems evolving after a
quantum quench.


title: Resonances in the heavy symmetrical top with vibrating pivot

abstract:
  In this work we consider a heavy symmetrical top whose pivot is subjected to
vertical and horizontal vibrations, and derive a resonance criterion when the
top is thrown off the stable position.


title: Distributed boundary tracking using alpha and Delaunay-Cech shapes

abstract:
  For a given point set $S$ in a plane, we develop a distributed algorithm to
compute the $\alpha-$shape of $S$. $\alpha-$shapes are well known geometric
objects which generalize the idea of a convex hull, and provide a good
definition for the shape of $S$. We assume that the distances between pairs of
points which are closer than a certain distance $r>0$ are provided, and we show
constructively that this information is sufficient to compute the alpha shapes
for a range of parameters, where the range depends on $r$.
  Such distributed algorithms are very useful in domains such as sensor
networks, where each point represents a sensing node, the location of which is
not necessarily known.
  We also introduce a new geometric object called the Delaunay-\v{C}ech shape,
which is geometrically more appropriate than an $\alpha-$shape for some cases,
and show that it is topologically equivalent to $\alpha-$shapes.


title:
Room Temperature Nanoscale Ferroelectricity in Magnetoelectric GaFeO3
  Epitaxial Thin Films

abstract:
  We demonstrate room temperature ferroelectricity in the epitaxial thin films
of magnetoelectric GaFeO3. Piezo-force measurements show a 180o phase shift of
piezoresponse upon switching the electric field indicating nanoscale
ferroelectricity in epitaxial thin films of gallium ferrite. Further,
temperature dependent impedance analysis with and without the presence of an
external magnetic field clearly reveals a pronounced magneto-dielectric effect
across the magnetic transition temperature. In addition, our first principles
calculations show that Fe ions are not only responsible for ferrimagnetism as
observed earlier, but also give rise to the observed ferroelectricity, making
GFO an unique single phase multiferroic.


title: On the rotational dynamics of Prometheus and Pandora

abstract:
  Possible rotation states of two satellites of Saturn, Prometheus (S16) and
Pandora (S17), are studied by means of numerical experiments. The attitude
stability of all possible modes of synchronous rotation and the motion close to
these modes is analyzed by means of computation of the Lyapunov spectra of the
motion. The stability analysis confirms that the rotation of Prometheus and
Pandora might be chaotic, though the possibility of regular behaviour is not
excluded. For the both satellites, the attitude instability zones form series
of concentric belts enclosing the main synchronous resonance center in the
phase space sections. A hypothesis is put forward that these belts might form
"barriers" for capturing the satellites in synchronous rotation. The satellites
in chaotic rotation can mimic ordinary regular synchronous behaviour: they
preserve preferred orientation for long periods of time, the largest axis of
satellite's figure being directed approximately towards Saturn.


title:
H\"ormander's theorem for parabolic equations with coefficients
  measurable in the time variable

abstract:
  We are dealing with possibly degenerate second-order parabolic operators
whose coefficients are infinitely differentiable with respect to space
variables and only measurable with respect to the time variable. We impose the
H\"ormander condition on the diffusion coefficients and prove that the
solutions of the corresponding equations with right-hand sides which are
infinitely differentiable in the space variables in a space-time domain have
also this property.


title: Role of exciton screening in the 7/3 fractional quantum Hall effect

abstract:
  The excitations of the 7/3 fractional Hall state, one of the most prominent
states in the second Landau level, are not understood. We study the effect of
screening by composite fermion excitons and find that it causes a strong
renormalization at 7/3, thanks to a relatively small exciton gap and a
relatively large residual interaction between composite fermions. The
excitations of the 7/3 state are to be viewed as composite fermions dressed by
a large exciton cloud. Their wide extent has implications for experiments as
well as for analysis of finite system exact diagonalization studies.


title: VB-algebroid morphisms and representations up to homotopy

abstract:
  We show in this paper that the correspondence between $2$-term
representations up to homotopy and $\mathcal{VB}$-algebroids, established by
Gracia-Saz and Mehta, holds also at the level of morphisms. This correspondence
is hence an equivalence of categories. As an application, we study foliations
and distributions on a Lie algebroid, that are compatible both with the linear
structure and the Lie algebroid structure. In particular, we show how
infinitesimal ideal systems in a Lie algebroid $A$ are related with
subrepresentations of the adjoint representation of $A$.


title: A solution concept for games with altruism and cooperation

abstract:
  Over the years, numerous experiments have been accumulated to show that
cooperation is not casual and depends on the payoffs of the game. These
findings suggest that humans have attitude to cooperation by nature and the
same person may act more or less cooperatively depending on the particular
payoffs. In other words, people do not act a priori as single agents, but they
forecast how the game would be played if they formed coalitions and then they
play according to their best forecast. In this paper we formalize this idea and
we define a new solution concept for one-shot normal form games. We prove that
this \emph{cooperative equilibrium} exists for all finite games and it explains
a number of different experimental findings, such as (1) the rate of
cooperation in the Prisoner's dilemma depends on the cost-benefit ratio; (2)
the rate of cooperation in the Traveler's dilemma depends on the bonus/penalty;
(3) the rate of cooperation in the Publig Goods game depends on the pro-capite
marginal return and on the numbers of players; (4) the rate of cooperation in
the Bertrand competition depends on the number of players; (5) players tend to
be fair in the bargaining problem; (6) players tend to be fair in the Ultimatum
game; (7) players tend to be altruist in the Dictator game; (8) offers in the
Ultimatum game are larger than offers in the Dictator game.


title:
Magnetic state of pyrochlore Cd2Os2O7 emerging from strong competition
  of ligand distortions and longer-range crystalline anisotropy

abstract:
  By many-body quantum-chemical calculations, we investigate the role of two
structural effects - local ligand distortions and the anisotropic Cd-ion
coordination - on the magnetic state of Cd2Os2O7, a spin S=3/2 pyrochlore. We
find that these effects strongly compete, rendering the magnetic interactions
and ordering crucially depend on these geometrical features. Without trigonal
distortions a large easy-plane magnetic anisotropy develops. Their presence,
however, reverses the sign of the zero-field splitting and causes a large
easy-axis anisotropy (D = -6.8 meV), which in conjunction with the
antiferromagnetic exchange interaction (J = 6.4 meV) stabilizes an
all-in/all-out magnetic order. The competition uncovered here is a generic
feature of pyrochlore magnets.


title: Low-energy non-linear excitations in sphere packings

abstract:
  We study theoretically and numerically how hard frictionless particles in
random packings can rearrange. We demonstrate the existence of two distinct
unstable non-linear modes of rearrangement, both associated with the opening
and the closing of contacts. Mode one, whose density is characterized by some
exponent {\theta}', corresponds to motions of particles extending throughout
the entire system. Mode two, whose density is characterized by an exponent
{\theta} != {\theta}', corresponds to the local buckling of a few particles.
Mode one is shown to yield at a much higher rate than mode two when a stress is
applied. We show that the distribution of contact forces follows P(f)
f^{min({\theta}',{\theta})}, and that imposing that the packing cannot be
densified further leads to the bounds {\gamma} >= 1/(2+{\theta}') and {\gamma}
>= (1-{\theta})/2, where {\gamma} characterizes the singularity of the pair
distribution function g(r) at contact. These results extend the theoretical
analysis of [M. Wyart, Phys. Rev. Lett 109, 125502 (2012)] where the existence
of mode two was not considered. We perform numerics that support that these
bounds are saturated with {\gamma} \approx 0.38, {\theta} \approx 0.17 and
{\theta}' \approx 0.44. We measure systematically the stability of all such
modes in packings, and confirm their marginal stability. The principle of
marginal stability thus allows to make clearcut predictions on the ensemble of
configurations visited in these out-of-equilibrium systems, and on the contact
forces and pair distribution functions. It also reveals the excitations that
need to be included in a description of plasticity or flow near jamming, and
suggests a new path to study two-level systems and soft spots in simple
amorphous solids of repulsive particles.


title: Fermion mixing with geometrical CP violation and its tests at the LHC

abstract:
  We review and clarify some cases of geometrical CP violation, the framework
of spontaneous CP violation through complex phases with values that are
independent of parameters of the potential. We present a flavour model based on
Delta(27) featuring spontaneous CP violation, that can reproduce all quark
masses and mixing data. The scalar sector of the model has exotic properties
that can be tested at the LHC.


title:
An algebro-geometric construction of lower central series of associative
  algebras

abstract:
  The lower central series invariants M_k of an associative algebra A are the
two-sided ideals generated by k-fold iterated commutators; the M_k provide a
filtration of A. We study the relationship between the geometry of X = Spec
A_ab and the associated graded components N_k of this filtration. We show that
the N_k form coherent sheaves on a certain nilpotent thickening of X, and that
Zariski localization on X coincides with noncommutative localization of A.
Under certain freeness assumptions on A, we give an alternative construction of
N_k purely in terms of the geometry of X (and in particular, independent of A).
Applying a construction of Kapranov, we exhibit the N_k as natural vector
bundles on the category of smooth schemes.


title:
Transverse electric conductivity and dielectric permeability in quantum
  non-degenerate and maxwellian collisional plasma with variable collision
  frequency in Mermin's approach

abstract:
  Formulas for transverse conductance and dielectric permeability in quantum
non-degenerate and Maxwellian collisional plasma with arbitrary variable
collision frequency in Mermin's approach are deduced. Frequency of collisions
of particles depends arbitrarily on a wave vector. The special case of
frequency of collisions proportional to the module of a wave vector is
considered. The graphic analysis of the real and imaginary parts of dielectric
function is made.


title: Real Analytic Solutions to the Willmore Flow

abstract:
  In this paper, a regularity result for the Willmore flow is presented. It is
established by means of a truncated translation technique in conjunction with
the Implicit Function Theorem.


title: Maximum likelihood estimation of local stellar kinematics

abstract:
  Context. Kinematical data such as the mean velocities and velocity
dispersions of stellar samples are useful tools to study galactic structure and
evolution. However, observational data are often incomplete (e.g., lacking the
radial component of the motion) and may have significant observational errors.
For example, the majority of faint stars observed with Gaia will not have their
radial velocities measured. Aims. Our aim is to formulate and test a new
maximum likelihood approach to estimating the kinematical parameters for a
local stellar sample when only the transverse velocities are known (from
parallaxes and proper motions). Methods. Numerical simulations using
synthetically generated data as well as real data (based on the
Geneva-Copenhagen survey) are used to investigate the statistical properties
(bias, precision) of the method, and to compare its performance with the much
simpler "projection method" described by Dehnen & Binney (1998). Results. The
maximum likelihood method gives more correct estimates of the dispersion when
observational errors are important, and guarantees a positive-definite
dispersion matrix, which is not always obtained with the projection method.
Possible extensions and improvements of the method are discussed.


title: Intrinsic curvature determines the crinkled edges of "crenellated disks"

abstract:
  Elastic curvature constants determine many structural and functional
properties of fluid membranes. Methods to measure the mean curvature modulus
have proved to be robust. In contrast, Gaussian curvature is an intrinsic
property of a surface. Thus, measuring the relevant modulus $\bar{k}$ in fluid
membranes remains a challenging task. Inspired from colloidal "crenellated
disks" observed in a model system composed of hard rods, we propose a concise
relation between the two curvature moduli and the parameters associated with
the free, crinkled edges. Our approach offers a straightforward way to
determine $\bar{k}$ of these reconfigurable membranes, where various complex
topologies can be nanosculpted. Further, we reveal the structure and stability
of the "crenellated disks."


title:
Predicting growth and finding biomass production using the general
  growth mechanism

abstract:
  First, we briefly describe the general growth mechanism, which governs the
growth of living organisms, and its mathematical representation, the growth
equation. Using the growth equation, we compute growth curve for S. cerevisiae
and show that it corresponds to available experimental data. Then, we propose a
new method for finding amount of synthesized biomass without complicated
stoichiometric computations and apply this method to evaluation of biomass
production by S. cerevisiae. We found that obtained results are very close to
values obtained by methods of metabolic flux analysis. Since methods of
metabolic flux analysis require finding produced biomass, which is one of the
most important parameters affecting stoichiometric models, a priori knowledge
of produced biomass can significantly improve methods of metabolic flux
analysis in many aspects, which we also discuss. Besides, based on the general
growth mechanism, we considered evolutionary development of S. cerevisiae and
found that it is a more ancient organism than S. pombe and is apparently its
direct predecessor.


title:
Dynamic Generation of Topologically Protected Self-Correcting Quantum
  Memory

abstract:
  We propose a scheme to dynamically realize a quantum memory based on the
toric code. The code is generated from qubit systems with typical two-body
interactions (Ising, XY, Heisenberg) using periodic, NMR-like, pulse sequences.
It allows one to encode the logical qubits without measurements and to protect
them dynamically against the time evolution of the physical qubits. A weakly
coupled cavity mode mediates a long-range attractive interaction between the
stabilizer operators of the toric code, thereby suppressing the creation of
thermal anyons. This significantly increases the lifetime of the memory
compared to the code with noninteracting stabilizers. We investigate how the
fidelity, with which the toric code is realized, depends on the period length T
of the pulse sequence and the magnitude of possible pulse errors. We derive an
optimal period T_opt that maximizes the fidelity.


title: Mechanotaxis and cell motility

abstract:
  We propose a mechanism of cell motility which is based on contraction and
does not require protrusion. The contraction driven translocation of a cell is
due to internal flow of the cytoskeleton generated by molecular motors. Each
motor contributes to the stress field and simultaneously undergoes biased
random motion in the direction of a higher value of this stress. In this way
active cross-linkers use passive actin network as a medium through which they
interact and self-organize. The model exhibits motility initiation pattern
similar to the one observed in experiments on keratocytes.


title: ClusCo: clustering and comparison of protein models

abstract:
  Background: The development, optimization and validation of protein modeling
methods require efficient tools for structural comparison. Frequently, a large
number of models need to be compared with the target native structure. The main
reason for the development of Clusco software was to create a high-throughput
tool for all-versus-all comparison, because calculating similarity matrix is
the one of the bottlenecks in the protein modeling pipeline. Results: Clusco is
fast and easy-to-use software for high-throughput comparison of protein models
with different similarity measures (cRMSD, dRMSD, GDT_TS, TM-Score, MaxSub,
Contact Map Overlap) and clustering of the comparison results with standard
methods: K-means Clustering or Hierarchical Agglomerative Clustering.
Conclusions: The application was highly optimized and written in C/C++,
including the code for parallel execution on CPU and GPU version of cRMSD,
which resulted in a significant speedup over similar clustering and scoring
computation programs.


title:
Optimal chattering solutions for longitudinal vibrations of a
  nonhomogeneous bar

abstract:
  We consider a control problem for longitudinal vibrations of a nonhomogeneous
bar with clamped ends. The vibrations of the bar are controlled by an external
force which is distributed along the bar. For the minimization problem of mean
square deviation of the bar we prove that the optimal control has an infinite
number of switchings in a finite time interval, i.e., the optimal control is
the chattering control.


title: An asymmetry between pushing and pulling for crawling cells

abstract:
  Eukaryotic cells possess motility mechanisms allowing them not only to
self-propel but also to exert forces on obstacles (to push) and to carry
cargoes (to pull). To study the inherent asymmetry between active pushing and
pulling we model a crawling acto-myosin cell extract as a 1D layer of active
gel subjected to external forces. We show that pushing is controlled by
protrusion and that the macroscopic signature of the protrusion dominated
motility mechanism is concavity of the force velocity relation. Instead,
pulling is driven by protrusion only at small values of the pulling force and
it is replaced by contraction when the pulling force is sufficiently large.
This leads to more complex convex-concave structure of the force velocity
relation, in particular, competition between protrusion and contraction can
produce negative mobility in a biologically relevant range. The model
illustrates active readjustment of the force generating machinery in response
to changes in the dipole structure of external forces. The possibility of
switching between complementary active mechanisms implies that if necessary
'pushers' can replace 'pullers' and visa versa.


title: Selecting Boron Fullerenes by Cage-Doping Mechanisms

abstract:
  So far, no boron fullerenes were synthesized: more compact sp3-bonded
clusters are energetically preferred. To circumvent this, metallic clusters
have been suggested by Pochet et al. [Phys. Rev. B 83, 081403(R) (2011)] as
"seeds" for a possible synthesis which would topologically protect the sp2
sector of the configuration space. In this paper, we identify a basic
pentagonal unit which allows a balance between the release of strain and the
self-doping rule. We formulate a guiding principle for the stability of boron
fullerenes, which takes the form of an isolated filled pentagon rule (IFPR).
The role of metallic clusters is then reexamined. It is shown that the
interplay of the IFPR and the seed-induced doping breaks polymorphism and its
related problems: it can effectively select between different isomers and
reduce the reactivity of the boron shells. The balance between self and
exterior doping represents the best strategy for boron buckyball synthesis.


title:
Generalizing the Connes Moscovici Hopf algebra to contain all rooted
  trees

abstract:
  This paper defines a generalization of the Connes-Moscovici Hopf algebra,
$\mathcal{H}(1)$ that contains the entire Hopf algebra of rooted trees. A
relationship between the former, a much studied object in non-commutative
geometry, and the later, a much studied object in perturbative Quantum Field
Theory, has been established by Connes and Kreimer. The results of this paper
open the door to study the cohomology of the Hopf algebra of rooted trees.


title: Semiconvection: theory

abstract:
  A model is developed for the transport of heat and solute in a system of
double-diffusive layers under astrophysical conditions (viscosity and solute
diffusivity low compared with the thermal diffusivity). The process of
formation of the layers is not part of the model but, as observed in
geophysical and laboratory settings, is assumed to be fast compared to the life
time of the semiconvective zone. The thickness of the layers is \tbf{a} free
parameter of the model. When the energy flux of the star is specified, the
effective semiconvective diffusivities are only weakly dependent on this
parameter. An estimate is given of the evolution of layer thickness with time
in a semiconvective zone. The model predicts that the density ratio has a
maximum for which a stationary layered state can exist, $R_\rho\la
\mr{Le}^{-1/2}$. Comparison of the model predictions with a grid of numerical
simulations is presented in a companion paper.


title: Generic Strategies for Chemical Space Exploration

abstract:
  Computational approaches to exploring "chemical universes", i.e., very large
sets, potentially infinite sets of compounds that can be constructed by a
prescribed collection of reaction mechanisms, in practice suffer from a
combinatorial explosion. It quickly becomes impossible to test, for all pairs
of compounds in a rapidly growing network, whether they can react with each
other. More sophisticated and efficient strategies are therefore required to
construct very large chemical reaction networks.
  Undirected labeled graphs and graph rewriting are natural models of chemical
compounds and chemical reactions. Borrowing the idea of partial evaluation from
functional programming, we introduce partial applications of rewrite rules.
Binding substrate to rules increases the number of rules but drastically prunes
the substrate sets to which it might match, resulting in dramatically reduced
resource requirements. At the same time, exploration strategies can be guided,
e.g. based on restrictions on the product molecules to avoid the explicit
enumeration of very unlikely compounds. To this end we introduce here a generic
framework for the specification of exploration strategies in graph-rewriting
systems. Using key examples of complex chemical networks from sugar chemistry
and the realm of metabolic networks we demonstrate the feasibility of a
high-level strategy framework.
  The ideas presented here can not only be used for a strategy-based chemical
space exploration that has close correspondence of experimental results, but
are much more general. In particular, the framework can be used to emulate
higher-level transformation models such as illustrated in a small puzzle game.


title:
The Decimation Method for Laplacians on Fractals: Spectra and Complex
  Dynamics

abstract:
  In this survey article, we investigate the spectral properties of fractal
differential operators on self-similar fractals. In particular, we discuss the
decimation method, which introduces a renormalization map whose dynamics
describes the spectrum of the operator. In the case of the bounded Sierpinski
gasket, the renormalization map is a polynomial of one variable on the complex
plane. The decimation method has been generalized by C. Sabot to other fractals
with blow-ups and the resulting associated renormalization map is then a
multi-variable rational function on a complex projective space. Furthermore,
the dynamics associated with the iteration of the renormalization map plays a
key role in obtaining a suitable factorization of the spectral zeta function of
fractal differential operators. In this context, we discuss the works of A.
Teplyaev and of the authors regarding the examples of the bounded and unbounded
Sierpinski gaskets as well as of fractal Sturm-Liouville differential operators
on the half-line.


title: Time dependent Stark ladders: Exact propagator and caustic control

abstract:
  In this note we present a new propagator for a particle in discrete space
under the influence of a time-dependent field. With this result we are able to
control the shape of caustics emerging from a point-like source, as the
explicit form of the wavefronts can be put in terms of the external field.


title: Topological Subset Space Models for Public Announcements

abstract:
  We reformulate a key definition given by Wang and Agotnes (2013) to provide
semantics for public announcements in subset spaces. More precisely, we
interpret the precondition for a public announcement of {\phi} to be the "local
truth" of {\phi}, semantically rendered via an interior operator. This is
closely related to the notion of {\phi} being "knowable". We argue that these
revised semantics improve on the original and offer several motivating examples
to this effect. A key insight that emerges is the crucial role of topological
structure in this setting. Finally, we provide a simple axiomatization of the
resulting logic and prove completeness.


title:
Tap-Wave-Rub: Lightweight Malware Prevention for Smartphones Using
  Intuitive Human Gestures

abstract:
  In this paper, we introduce a lightweight permission enforcement approach -
Tap-Wave-Rub (TWR) - for smartphone malware prevention. TWR is based on simple
human gestures that are very quick and intuitive but less likely to be
exhibited in users' daily activities. Presence or absence of such gestures,
prior to accessing an application, can effectively inform the OS whether the
access request is benign or malicious. Specifically, we present the design of
two mechanisms: (1) accelerometer based phone tapping detection; and (2)
proximity sensor based finger tapping, rubbing or hand waving detection. The
first mechanism is geared for NFC applications, which usually require the user
to tap her phone with another device. The second mechanism involves very simple
gestures, i.e., tapping or rubbing a finger near the top of phone's screen or
waving a hand close to the phone, and broadly appeals to many applications
(e.g., SMS). In addition, we present the TWR-enhanced Android permission model,
the prototypes implementing the underlying gesture recognition mechanisms, and
a variety of novel experiments to evaluate these mechanisms. Our results
suggest the proposed approach could be very effective for malware detection and
prevention, with quite low false positives and false negatives, while imposing
little to no additional burden on the users.


title:
Approximation of stable random measures and applications to linear
  fractional stable integrals

abstract:
  Using lattice approximations of Euclidean space, we develop a way to
approximate stable processes that are represented by stochastic integrals over
Euclidean space. Via a stable version of the Lindeberg-Feller Theorem we show
that the approximations weakly converge as the mesh-size goes to zero. As an
application, we improve upon previous approximation schemes for integrals with
respect to linear fractional stable motions.