title: Processing Color in Astronomical Imagery

abstract:
  Every year, hundreds of images from telescopes on the ground and in space are
released to the public, making their way into popular culture through
everything from computer screens to postage stamps. These images span the
entire electromagnetic spectrum from radio waves to infrared light to X-rays
and gamma rays, a majority of which is undetectable to the human eye without
technology. Once these data are collected, one or more specialists must process
the data to create an image. Therefore, the creation of astronomical imagery
involves a series of choices. How do these choices affect the comprehension of
the science behind the images? What is the best way to represent data to a
non-expert? Should these choices be based on aesthetics, scientific veracity,
or is it possible to satisfy both? This paper reviews just one choice out of
the many made by astronomical image processors: color. The choice of color is
one of the most fundamental when creating an image taken with modern
telescopes. We briefly explore the concept of the image as translation,
particularly in the case of astronomical images from invisible portions of the
electromagnetic spectrum. After placing modern astronomical imagery and
photography in general in the context of its historical beginnings, we review
the standards (or lack thereof) in making the basic choice of color. We discuss
the possible implications for selecting one color palette over another in the
context of the appropriateness of using these images as science communication
products with a specific focus on how the non-expert perceives these images and
how that affects their trust in science. Finally, we share new data sets that
begin to look at these issues in scholarly research and discuss the need for a
more robust examination of this and other related topics in the future to
better understand the implications for science communications.


title:
Experimental evidence of a collinear antiferromagnetic ordering in the
  frustrated CoAl2O4 spinel

abstract:
  Nuclear magnetic resonance (NMR), neutron diffaction (ND), x-ray diffraction,
magnetic susceptibility and specific heat measurements on the frustrated A-site
spinel CoAl2O4 compound reveal a collinear antiferromagnetic ordering below Tn
= 9.8(2) K. A high quality powder sample characterized by x-ray diffraction
that indicates a relatively low Co-Al inversion parameter x = 0.057(20) in
(Co1-xAlx)[Al2-xCox]O4, shows a broad maximum around 15 K in magnetic
susceptibility and a sharp peak at Tn in heat capacity. The average ordered
magnetic moment of Co^2+ (S = 3/2) ions at the A-site is estimated to be 2.4(1)
Bohr magneton from NMR and 1.9(5) Bohr magneton from ND which are smaller than
the expected value of 3 Bohr magneton for S = 3/2 and g = 2. Antiferromagnetic
spin uctuations and correlations in the paramagnetic state are revealed from
the magnetic susceptibility, NMR and ND measurements, which are due to spin
frustration and site inversion effects in the system. The ND data also show
short-range dynamic magnetic ordering that persists to a temperature that is
almost twice Tn.


title: On Locally Decodable Source Coding

abstract:
  Locally decodable channel codes form a special class of error-correcting
codes with the property that the decoder is able to reconstruct any bit of the
input message from querying only a few bits of a noisy codeword. It is well
known that such codes require significantly more redundancy (in particular have
vanishing rate) compared to their non-local counterparts. In this paper, we
define a dual problem, i.e. locally decodable source codes (LDSC). We consider
both almost lossless (block error) and lossy (bit error) cases. In almost
lossless case, we show that optimal compression (to entropy) is possible with
O(log n) queries to compressed string by the decompressor. We also show the
following converse bounds: 1) linear LDSC cannot achieve any rate below one,
with a bounded number of queries, 2) rate of any source coding with linear
decoder (not necessarily local) in one, 3) for 2 queries, any code construction
cannot have a rate below one. In lossy case, we show that any rate above rate
distortion is achievable with a bounded number of queries. We also show that,
rate distortion is achievable with any scaling number of queries. We provide an
achievability bound in the finite block-length regime and compare it with the
existing bounds in succinct data structures literature.


title:
Gravitational Waves and Inspiraling Compact Binaries in Alternative
  Theories of Gravity

abstract:
  This dissertation consists of four parts. In Part I, we briefly review
fundamental theories of gravity, performed experimental tests, and
gravitational waves. The framework and the methods that we use in our
calculations are discussed in Part II. This part includes reviewing the methods
of the Parametrized Post-Newtonian (PPN) framework, Direct Integration of
Relaxed Einstein Equations (DIRE), and Matched Filtering.
  In Part III, we calculate the explicit equations of motion for non-spinning
compact objects (neutron stars or black holes) to 2.5 post-Newtonian order, or
$O(v/c)^5$ beyond Newtonian gravity, in a general class of alternative theories
to general relativity known as scalar-tensor theories. For the conservative
part of the motion, we obtain the two-body Lagrangian and conserved energy and
momentum through second post-Newtonian order. We find the contributions to
gravitational radiation reaction to 1.5 post-Newtonian and 2.5 post-Newtonian
orders, the former corresponding to the effects of dipole gravitational
radiation. For binary black holes we show that the motion through 2.5
post-Newtonian order is observationally identical to that predicted by general
relativity.
  In Part IV, we construct a parametrized dispersion relation that can produce
a range of predictions of alternative theories of gravity for violations of
Lorentz invariance in gravitation, and investigate their impact on the
propagation of gravitational waves. We show how such corrections map to the
waveform observable by a gravitational-wave detector, and to the "parametrized
post-Einsteinian framework", proposed to model a range of deviations from
General Relativity. Given a gravitational-wave detection, the lack of evidence
for such corrections could then be used to place a constraint on Lorentz
violation.


title:
From 10 Kelvin to 10 TeraKelvin: Insights on the Interaction Between
  Cosmic Rays and Gas in Starbursts

abstract:
  Recent work has both illuminated and mystified our attempts to understand
cosmic rays (CRs) in starburst galaxies. I discuss my new research exploring
how CRs interact with the ISM in starbursts. Molecular clouds provide targets
for CR protons to produce pionic gamma rays and ionization, but those same
losses may shield the cloud interiors. In the densest molecular clouds, gamma
rays and Al-26 decay can provide ionization, at rates up to those in Milky Way
molecular clouds. I then consider the free-free absorption of low frequency
radio emission from starbursts, which I argue arises from many small, discrete
H II regions rather than from a "uniform slab" of ionized gas, whereas
synchrotron emission arises outside them. Finally, noting that the hot
superwind gas phase fills most of the volume of starbursts, I suggest that it
has turbulent-driven magnetic fields powered by supernovae, and that this phase
is where most synchrotron emission arises. I show how such a scenario could
explain the far-infrared radio correlation, in context of my previous work. A
big issue is that radio and gamma-ray observations imply CRs also must interact
with dense gas. Understanding how this happens requires a more advanced
understanding of turbulence and CR propagation.


title:
CP violation induced by the interference of scalar and vector resonances
  in three-body decays of bottom mesons

abstract:
  Large CP violation is an interesting phenomenon both theoretically and
experimentally. Last year, LHCb Collaboration found in some three-body decays
of bottom mesons that large CP violations appear in regions of the Dalitz plots
that are not dominated by contributions from narrow resonances. In this paper,
we present a mechanism which can induce such kind of large CP violations. In
this mechanism, large localized CP asymmetries in phase space can be induced by
the interference of two intermediate resonances with different spins. We also
apply this mechanism to the decay channel $B^\pm\to K^\pm \pi^+\pi^-$.


title: Sterile neutrinos in U(1)' with R-parity Violation

abstract:
  Motivated by results from short-baseline neutrino oscillation data, we study
neutrino masses and mixing in U(1)' supersymmetric models with R-parity
breaking. Whether R-parity is broken spontaneous or through (effective)
bilinear terms in the Lagrangian, the breaking terms induce mixing between the
neutralinos and neutrinos, creating a scenario in which some neutralinos can be
heavy, and some light. Both the right-handed neutrino and the singlino
(fermionic partner of the additional singlet Higgs field) can be light, and act
as sterile neutrinos, which reconcile some of the anomalies observed in solar
baseline and reactor experiments. We show that, scanning a large range of the
parameter space satisfying solar and atmospheric neutrino constraints, the mass
and mixing parameters of the sterile neutrinos are very restrictive, leading to
some predictive features for the U(1)' scenarios.


title: Liquid to solid nucleation via onion structure droplets

abstract:
  We study homogeneous nucleation from a deeply quenched metastable liquid to a
spatially modulated phase. We find, for a general class of density functional
theories, that the universally favored nucleating droplet in dimensions $d \geq
3$ is spherically symmetric with radial modulations resembling the layers of an
onion. The existence of this droplet has important implications for systems
with effective long-range interactions, and potentially applies to polymers,
plasmas, and metals.


title:
X-ray photodesorption and proton destruction in protoplanetary disks:
  pyrimidine

abstract:
  The organic compounds HCN and C2H2, present in protoplanetary disks, may
react to form precursor molecules of the nucleobases, such as the pyrimidine
molecule, C4H4N2. Depending on the temperature in a given region of the disk,
molecules are in the gas phase or condensed onto grain surfaces. The action of
X-ray photons and MeV protons, emitted by the young central star, may lead to
several physical and chemical processes in such prestellar environments. In
this work we have experimentally investigated the ionization, dissociation and
desorption processes of pyrimidine in the condensed and the gas phase
stimulated by soft X-rays and protons, respectively. Pyrimidine was frozen at
temperatures below 130 K and irradiated with X-rays at energies from 394 to 427
eV. In the gas phase experiment, a pyrimidine effusive jet at room temperature
was bombarded with protons of 2.5 MeV. In both experiments, the time-of-flight
mass-spectrometry technique was employed. Partial photodesorption ion yields as
a function of the X-ray photon energy for ions such as C3H2+, HC3NH+ and C4H+
were determined. The experimental results were applied to conditions of the
protoplanetary disk of TW Hydra star. Assuming three density profiles of
molecular hydrogen, 1 x 10^6, 1 x 10^7 and 1 x 10^8 cm^-3, we determined HC3NH+
ion-production rates of the order of 10^-31 up to 10^-8 ions cm^-3 s^-1.
Integrating over 1 x 10^6 yr, HC3NH^+ column density values, ranging from 3.47
x 10^9 to 1.29 x 10^13 cm^-2, were obtained as a function of the distance from
central star. The optical depth is the main variable that affects ions
production. In addition, computational simulations were used to determine the
kinetic energies of ions desorbed from pyrimidine ice distributed between ~ 7
and 15 eV.


title:
The critical compressibility factor of fluids from the Global
  Isomorphism approach

abstract:
  The relation between the critical compressibility factors $Z_{c}$ of the
Lennard-Jones fluid and the Lattice Gas (Ising model) is derived within the
global isomorphism approach. On this basis we obtain the alternative form for
the value of the critical compressibility factor which is different from widely
used phenomenological Timmermans relation. The estimates for the critical
pressure $P_c$ and $Z_c$ of the Lennard-Jones fluid are obtained in case of two
and three dimensions. The extension of the formalism is proposed to include the
Pitzer's acentric factor into consideration.


title: Spectral C*-categories and Fell bundles with path-lifting

abstract:
  Following Crane's suggestion that categorification should be of fundamental
importance in quantising gravity, we show that finite dimensional even
$S^o$-real spectral triples over $\bbc$ are already nothing more than full
C*-categories together with a self-adjoint section of their domain and range
maps, while the latter are equivalent to unital saturated Fell bundles over
pair groupoids equipped with a path-lifting operator given by a normaliser.
Interpretations can be made in the direction of quantum Higgs gravity. These
geometries are automatically quantum geometries and we reconstruct the
classical limit, that is, general relativity on a Riemannian spin manifold.


title: Arithmetic progressions in sets of small doubling

abstract:
  We show that if a finite, large enough subset A of an arbitrary abelian group
satisfies the small doubling condition |A + A| < (log |A|)^{1 - epsilon} |A|,
then A must contain a three-term arithmetic progression whose terms are not all
equal, and A + A must contain an arithmetic progression or a coset of a
subgroup, either of which of size at least exp^[ c (log |A|)^{delta} ]. This
extends analogous results obtained by Sanders and, respectively, by Croot, Laba
and Sisask in the case where the group is that of the integers or a finite
field.


title: A Note on Sparsification by Frames

abstract:
  The purpose of this note is to establish a new generalized
Dictionary-Restricted Isometry Property (D-RIP) sparsity bound constant for
compressed sensing.
  For fulfilling D-RIP, the constant $\delta_k$ is used in the definition: $(1
-\delta_k)\|D v\|_2^2 \le \|\Phi D v\|_2^2 \le (1 + \delta_k)\|D v\|^2$. We
prove that signals with $k$-sparse $D$-representation can be reconstructed if
$\delta_{2k} < \frac{2}3$.
  The approach in this note can be extended to obtain other D-RIP bounds (i.e.,
$\delta_{tk}$).


title: Rayleigh-Taylor instability of ionization front around black holes

abstract:
  We examine the role of ionizing radiation emitted from black holes (BHs) in
suppressing the growth of the Rayleigh-Taylor instability (RTI) across the
ionization front (I-front) that forms when the gas fueling the BH is neutral.
We use radiation-hydrodynamic simulations to show that the RTI is suppressed
for non-accelerating fronts on all scales resolved in our simulations. A
necessary condition for the stability of the I-front is that the radius of the
Str\"omgren sphere is larger than the Bondi radius. When this condition is
violated the I-front collapses producing an accretion luminosity burst.
Transient growth of the RTI occurs only during the accretion burst when the
effective acceleration in the frame of reference of the I-front increases
significantly due to the rapid expansion of the Str\"omgren sphere.


title: Light-Front Holographic QCD and the Confinement Potential

abstract:
  Light-Front Hamiltonian theory, derived from the quantization of the QCD
Lagrangian at fixed light-front time \tau = t+z/c, provides a rigorous
frame-independent framework for solving nonperturbative QCD. The eigenvalues of
the light-front QCD Hamiltonian predict the hadronic mass spectrum, and the
eigensolutions provide the light-front wavefunctions describing hadron
structure. The valence Fock-state wavefunctions of the light-front QCD
Hamiltonian satisfy a single-variable relativistic equation of motion,
analogous to the nonrelativistic radial Schrodinger equation, with an effective
confining potential U which systematically incorporates the effects of higher
quark and gluon Fock states. The potential U has a unique form if one requires
that the action for zero quark mass remains conformally invariant. The
holographic mapping of gravity in AdS space to QCD with a specific soft-wall
dilaton yields the same light-front Schrodinger equation. It also gives a
precise relation between the bound-state amplitudes in the fifth dimension z of
AdS space and the boost-invariant light-front wavefunctions describing the
internal structure of hadrons in physical space-time. The elastic and
transition form factors of the pion and the nucleons are found to be well
described in this framework. The predictions include a zero-mass pion in the
chiral limit, and linear Regge trajectories with the same slope in the radial
quantum number n and orbital angular momentum L. The light-front AdS/QCD
holographic approach thus gives a frame-independent representation of
color-confining dynamics and the excitation spectra of light-quark hadrons in
terms of a single mass parameter. We also discuss the implications of the
underlying conformal template of QCD for renormalization scale-setting and the
implications of light-front quantization for the value of the cosmological
constant.


title:
Discovery of Four High Proper Motion L Dwarfs, Including a 10 pc L Dwarf
  at the L/T Transition

abstract:
  We discover four high proper motion L dwarfs by comparing the Wide-field
Infrared Survey Explorer (WISE) to the Two Micron All Sky Survey (2MASS). WISE
J140533.32+835030.5 is an L dwarf at the L/T transition with a proper motion of
0.85+/-0.02" yr^-1, previously overlooked due to its proximity to a bright star
(V=12 mag). From optical spectroscopy we find a spectral type of L8, and from
moderate-resolution J band spectroscopy we find a near-infrared spectral type
of L9. We find WISE J140533.32+835030.5 to have a distance of 9.7+/-1.7 pc,
bringing the number of L dwarfs at the L/T transition within 10 pc from six to
seven. WISE J040137.21+284951.7, WISE J040418.01+412735.6, and WISE
J062442.37+662625.6 are all early L dwarfs within 25 pc, and were classified
using optical and low-resolution near-infrared spectra. WISE
J040418.01+412735.6 is an L2 pec (red) dwarf, a member of the class of
unusually red L dwarfs. We use follow-up optical and low-resolution
near-infrared spectroscopy to classify a previously discovered (Castro & Gizis
2012) fifth object WISEP J060738.65+242953.4 as an (L8 Opt/L9 NIR), confirming
it as an L dwarf at the L/T transition within 10 pc. WISEP J060738.65+242953.4
shows tentative CH_4 in the H band, possibly the result of unresolved binarity
with an early T dwarf, a scenario not supported by binary spectral template
fitting. If WISEP J060738.65+242953.4 is a single object, it represents the
earliest onset of CH_4 in the H band of an L/T transition dwarf in the SpeX
Library. As very late L dwarfs within 10 pc, WISE J140533.32+835030.5 and WISEP
J060738.65+242953.4 will play a vital role in resolving outstanding issues at
the L/T transition.


title: On Cohomology and vector bundles over monoid schmes

abstract:
  The aim of this paper is to study the cohomology theory of monoid schemes in
general and apply it to vector and line bundles. We will prove that over
separated monoid schemes, any vector bundle is a coproduct of line bundles and
then go on to study the line bundles in more detail. Amongst other things, we
prove that over separated monoid schemes, ${\sf Pic}$ respects finite products.
  Next we will introduce the notion of $s$-cancellative monoids. They are
monoids for which $ax=ay$ implies that $(xy)^nx=(xy)^ny, n\in\mathbb{N}$. This
class is important since it is the biggest class of monoids for which
$M^*_{\mathfrak{p}}$ maps injectively into its group of fractions for every
prime ideal ${\mathfrak{p}}$. As we will see in section 6, this will enable us
to embed $\mathcal{O}^*_X$ injectively in a constant sheaf provided $X$ is
locally $s$-cancellative. We develop the theory of $s$-divisors and we prove
that for an $s$-cancellative monoid scheme $X$, the group ${\sf Pic}(X)$ can be
described in terms of $s$-divisors. For cancellative monoid schemes,
$s$-divisors agree with the Cartier divisors.
  We then introduce the notion of $s$-smooth monoid schemes, which generalise
smooth monoids schemes, and prove that for them $H^i(X,\mathcal{O}^*_X)=0$ for
all $i\geq 2$. Furthermore we show that it is a local property and respects
finite products.
  Finally we investigate the relationship between line bundles over a monoid
scheme $X$ and over its geometric realisation $X_k$, where $k$ is a commutative
ring. We prove that if $k$ is an integral domain (resp. principal ideal domain)
and $X$ is a cancellative and torsion free (resp. seminormal and torsion-free)
monoid scheme, then the induced map ${\sf Pic}(X)\to {\sf Pic}(X_k)$ is a
monomorphism (resp. isomorphism).


title:
A network approach to analyzing highly recombinant malaria parasite
  genes

abstract:
  The var genes of the human malaria parasite Plasmodium falciparum present a
challenge to population geneticists due to their extreme diversity, which is
generated by high rates of recombination. These genes encode a primary antigen
protein called PfEMP1, which is expressed on the surface of infected red blood
cells and elicits protective immune responses. Var gene sequences are
characterized by pronounced mosaicism, precluding the use of traditional
phylogenetic tools that require bifurcating tree-like evolutionary
relationships. We present a new method that identifies highly variable regions
(HVRs), and then maps each HVR to a complex network in which each sequence is a
node and two nodes are linked if they share an exact match of significant
length. Here, networks of var genes that recombine freely are expected to have
a uniformly random structure, but constraints on recombination will produce
network communities that we identify using a stochastic block model. We
validate this method on synthetic data, showing that it correctly recovers
populations of constrained recombination, before applying it to the Duffy
Binding Like-{\alpha} (DBL{\alpha}) domain of var genes. We find nine HVRs
whose network communities map in distinctive ways to known DBL{\alpha}
classifications and clinical phenotypes. We show that the recombinational
constraints of some HVRs are correlated, while others are independent. These
findings suggest that this micromodular structuring facilitates independent
evolutionary trajectories of neighboring mosaic regions, allowing the parasite
to retain protein function while generating enormous sequence diversity. Our
approach therefore offers a rigorous method for analyzing evolutionary
constraints in var genes, and is also flexible enough to be easily applied more
generally to any highly recombinant sequences.

categories: q-bio.GN physics.data-an q-bio.MN q-bio.PE q-bio.QM


title:
Multi-azimuthal-angle instability for different supernova neutrino
  fluxes

abstract:
  It has been recently discovered that removing the axial symmetry in the
"multi-angle effects" associated with the neutrino-neutrino interactions for
supernova (SN) neutrinos, a new multi-azimuthal-angle (MAA) instability would
trigger flavor conversions in addition to the ones caused by the bimodal and
multi-zenith-angle (MZA) instabilities. We investigate the dependence of the
MAA instability on the original SN neutrino fluxes, performing a stability
analysis of the linearized neutrino equations of motion. We compare these
results with the numerical evolution of the SN neutrino non-linear equations,
looking at a local solution along a specific line of sight, under the
assumption that the transverse variations of the global solution are small. We
also assume that self-induced conversions are not suppressed by large matter
effects. We show that the pattern of the spectral crossings (energies where
F_{\nu_e} = F_{\nu_x}, and F_{\bar\nu_e} = F_{\bar\nu_x}) is crucial in
determining the impact of MAA effects on the flavor evolution. For neutrino
spectra with a strong excess of \nu_e over \bar\nu_e, presenting only a
single-crossing, MAA instabilities would trigger new flavor conversions in
normal mass hierarchy. In our simplified flavor evolution scheme, these would
lead to spectral swaps and splits analogous to what produced in inverted
hierarchy by the bimodal instability. Conversely, in the presence of spectra
with a moderate flavor hierarchy, having multiple crossing energies, MZA
effects would produce a sizable delay in the onset of the flavor conversions,
inhibiting the growth of the MAA instability. In this case the splitting
features for the oscillated spectra in both the mass hierarchies are the ones
induced by the only bimodal and MZA effects.


title: Multireference Alignment using Semidefinite Programming

abstract:
  The multireference alignment problem consists of estimating a signal from
multiple noisy shifted observations. Inspired by existing Unique-Games
approximation algorithms, we provide a semidefinite program (SDP) based
relaxation which approximates the maximum likelihood estimator (MLE) for the
multireference alignment problem. Although we show that the MLE problem is
Unique-Games hard to approximate within any constant, we observe that our
poly-time approximation algorithm for the MLE appears to perform quite well in
typical instances, outperforming existing methods. In an attempt to explain
this behavior we provide stability guarantees for our SDP under a random noise
model on the observations. This case is more challenging to analyze than
traditional semi-random instances of Unique-Games: the noise model is on
vertices of a graph and translates into dependent noise on the edges.
Interestingly, we show that if certain positivity constraints in the SDP are
dropped, its solution becomes equivalent to performing phase correlation, a
popular method used for pairwise alignment in imaging applications. Finally, we
show how symmetry reduction techniques from matrix representation theory can
simplify the analysis and computation of the SDP, greatly decreasing its
computational cost.


title: Friendship and Natural Selection

abstract:
  More than any other species, humans form social ties to individuals who are
neither kin nor mates, and these ties tend to be with similar people. Here, we
show that this similarity extends to genotypes. Across the whole genome,
friends' genotypes at the SNP level tend to be positively correlated
(homophilic); however, certain genotypes are negatively correlated
(heterophilic). A focused gene set analysis suggests that some of the overall
correlation can be explained by specific systems; for example, an olfactory
gene set is homophilic and an immune system gene set is heterophilic. Finally,
homophilic genotypes exhibit significantly higher measures of positive
selection, suggesting that, on average, they may yield a synergistic fitness
advantage that has been helping to drive recent human evolution.


title:
On the electrodynamics of moving particles in a quasi flat spacetime
  with Lorentz violation and its cosmological implications

abstract:
  This research aims to develop a new approach toward a consistent coupling of
electromagnetic and gravitational fields by using an electron that couples with
a weak gravitational potential by means of its electromagnetic field. We find
the value of the tiny coupling constant of gravity with electromagnetic fields,
which depends on the speed of light and a universal minimum speed that
represents the lowest limit of speed for any particle. Such a minimum speed,
unattainable by particles, represents a preferred reference frame associated
with a background field that breaks the Lorentz symmetry. The metric of the
flat spacetime shall include the presence of a uniform vacuum energy density,
which leads to a negative pressure at cosmological scales, i.e., the
cosmological anti-gravity. The tiny values of the cosmological constant and the
vacuum energy density will be successfully obtained in agreement with the
observational data.


title:
Good formal structures for flat meromorphic connections, III:
  Irregularity and turning loci

abstract:
  Given a formal flat meromorphic connection over an excellent scheme over a
field of characteristic zero, in a previous paper we established existence of
good formal structures and a good Deligne-Malgrange lattice after suitably
blowing up. In this paper, we reinterpret and refine these results by
introducing some related structures. We consider the turning locus, which is
the set of points at which one cannot achieve a good formal structure without
blowing up. We show that when the polar divisor has normal crossings, the
turning locus is of pure codimension 1 within the polar divisor, and hence of
pure codimension 2 within the full space; this had been previously established
by Andre in the case of a smooth polar divisor. We also construct an
irregularity sheaf and its associated b-divisor, which measure irregularity
along divisors on blowups of the original space; this generalizes another
result of Andre on the semicontinuity of irregularity in a curve fibration. One
concrete consequence of these refinements is a process for resolution of
turning points which is functorial with respect to regular morphisms of
excellent schemes; this allows us to transfer the result from schemes to formal
schemes, complex analytic varieties, and nonarchimedean analytic varieties.


title:
A Search for Neutrino Emission from the Fermi Bubbles with the ANTARES
  Telescope

abstract:
  Analysis of the Fermi-LAT data has revealed two extended structures above and
below the Galactic Centre emitting gamma rays with a hard spectrum, the
so-called Fermi bubbles. Hadronic models attempting to explain the origin of
the Fermi bubbles predict the emission of high-energy neutrinos and gamma rays
with similar fluxes. The ANTARES detector, a neutrino telescope located in the
Mediterranean Sea, has a good visibility to the Fermi bubble regions. Using
data collected from 2008 to 2011 no statistically significant excess of events
is observed and therefore upper limits on the neutrino flux in TeV range from
the Fermi bubbles are derived for various assumed energy cutoffs of the source.


title:
Observability of Nonlinear Complex Networks in the Presence of
  Symmetries: A Graphical Approach

abstract:
  Reconstructing the states of the nodes of a dynamical network is a problem of
fundamental importance in the study of neuronal and genetic networks. An
underlying related problem is that of observability, i.e., identifying the
conditions under which such a reconstruction is possible. In this paper we
study observability of complex dynamical networks, where we consider the
effects of network symmetries on observability. We present an efficient
algorithm that returns a minimal set of necessary sensor nodes for
observability in the presence of symmetries.


title:
Examples of support varieties for Hopf algebras with noncommutative
  tensor products

abstract:
  The representations of some Hopf algebras have curious behavior:
Nonprojective modules may have projective tensor powers, and the variety of a
tensor product of modules may not be contained in the intersection of their
varieties. We explain a family of examples of such Hopf algebras and their
modules, and classify left, right, and two-sided ideals in their stable module
categories.


title: Non-Boussinesq Rolls in 2d Thermal Convection

abstract:
  A study of convection in a circular two dimensional cell is presented. The
system is heated and cooled at two diametrically opposed points on the edge of
the circle, which are parallel or anti-parallel to gravity. The latter's role
in the plane of the cell can be changed by tilting the cell. When the system is
in a horizontal position, a non-trivial analytic solution for the temperature
distribution of the quiescent fluid can be found. For a slight inclination, the
projection of gravity in the plane of the cell is used as a perturbation
parameter in the full hydrodynamic description, as the Boussinesq approximation
is inadequate. To first order, the equations are solved for the stationary case
and four symmetrical rolls become apparent, showing that a purely conductive
state is impossible if gravity -however small- is present; an approximate
closed analytical expression is obtained, which describes the four convection
rolls. Further analysis is done by a direct numerical integration. Comparison
with preliminary observations is mentioned.


title:
Super Lie n-algebra extensions, higher WZW models, and super p-branes
  with tensor multiplet fields

abstract:
  We formalize higher dimensional and higher gauge WZW-type sigma-model local
prequantum field theory, and discuss its rationalized/perturbative description
in (super-)Lie n-algebra homotopy theory (the true home of the "FDA"-language
used in the supergravity literature). We show generally how the intersection
laws for such higher WZW-type sigma-model branes (open brane ending on
background brane) are encoded precisely in (super-) L-infinity-extension theory
and how the resulting "extended (super-)spacetimes" formalize spacetimes
containing sigma model brane condensates. As an application we prove in Lie
n-algebra homotopy theory that the complete super p-brane spectrum of
superstring/M-theory is realized this way, including the pure sigma-model
branes (the "old brane scan") but also the branes with tensor multiplet
worldvolume fields, notably the D-branes and the M5-brane. For instance the
degree-0 piece of the higher symmetry algebra of 11-dimensional spacetime with
an M2-brane condensate turns out to be the "M-theory super Lie algebra". We
also observe that in this formulation there is a simple formal proof of the
fact that type IIA spacetime with a D0-brane condensate is the 11-dimensional
sugra/M-theory spacetime, and of (prequantum) S-duality for type IIB string
theory. Finally we give the non-perturbative description of all this by higher
WZW-type sigma-models on higher super-orbispaces with higher WZW terms in
stacky differential cohomology.


title: From Steiner Formulas for Cones to Concentration of Intrinsic Volumes

abstract:
  The intrinsic volumes of a convex cone are geometric functionals that return
basic structural information about the cone. Recent research has demonstrated
that conic intrinsic volumes are valuable for understanding the behavior of
random convex optimization problems. This paper develops a systematic technique
for studying conic intrinsic volumes using methods from probability. At the
heart of this approach is a general Steiner formula for cones. This result
converts questions about the intrinsic volumes into questions about the
projection of a Gaussian random vector onto the cone, which can then be
resolved using tools from Gaussian analysis. The approach leads to new
identities and bounds for the intrinsic volumes of a cone, including a
near-optimal concentration inequality.


title: Gold and Methane: A Noble Combination for Delicate Oxidation

abstract:
  The ability to partially oxidize methane at low temperatures and pressures
would have important environmental and economic applications. Although methane
oxidation on gold nanoparticles has been observed experimentally, our density
functional theory (DFT) calculations indicate neither CH4, CH3, nor H adsorb on
a neutral gold nanoparticle. However, by positively charging gold
nanoparticles, e.g. through charge transfer to the TiO2 substrate, CH4 binding
increases while O2 binding remains relatively unchanged. We demonstrate that
CH4 adsorption is via bonding with the metal s levels. This holds from small
gold clusters (Au2) to large gold nanoparticles (Au201), and for all fcc
transition metal dimers. These results provide the chemical understanding
necessary to tune the catalytic activity of metal nanoparticles for the partial
oxidation of methane under delicate conditions.


title:
Simultaneous Approximation of a Multivariate Function and its
  Derivatives by Multilinear Splines

abstract:
  In this paper we consider the approximation of a function by its
interpolating multilinear spline and the approximation of its derivatives by
the derivatives of the corresponding spline. We derive formulas for the uniform
approximation error on classes of functions with moduli of continuity bounded
above by certain majorants.


title: Kolmogorov's Problem on the Class of Multiply Monotone Functions

abstract:
  In this paper we give necessary and sufficient conditions for the system of
positive numbers $ M_{k_1}, M_{k_2},..., M_{k_{d}},$ $0\leq k_1<...<k_{d}
{\leq} r$, to guarantee the existence of an $r$-monotone function defined on
the negative half-line $\RR_-$ and such that $\|x^{(k_i)}\|_{\infty}=M_{k_i},
i=1,2,...,d$.


title: A comparative analysis of methods for estimating axon diameter using DWI

abstract:
  The importance of studying the brain microstructure is described and the
existing and state of the art non-invasive methods for the investigation of the
brain microstructure using Diffusion Weighted Magnetic Resonance Imaging (DWI)
is studied. In the next step, Cramer-Rao Lower Bound (CRLB) analysis is
described and utilised for assessment of the minimum estimation error and
uncertainty level of different Diffusion Weighted Magnetic Resonance (DWMR)
signal decay models. The analyses are performed considering the best scenario
through which, we assume that the models are the appropriate representation of
the measured phenomena. This includes the study of the sensitivity of the
estimations to the measurement and model parameters. It is demonstrated that
none of the existing models can achieve a reasonable minimum uncertainty level
under typical measurement setup. At the end, the practical obstacles for
achieving higher performance in clinical and experimental environments are
studied and their effects on feasibility of the methods are discussed.


title: A Multi-Wavelength Analysis of NGC 4178: A Bulgeless Galaxy with an AGN

abstract:
  We present {\it Gemini} longslit optical spectroscopy and VLA radio
observations of the nuclear region of NGC 4178, a late-type bulgeless disk
galaxy recently confirmed to host an AGN through infrared and X-ray
observations. Our observations reveal that the dynamical center of the galaxy
is coincident with the location of the {\it Chandra} X-ray point source
discovered in a previous work, providing further support for the presence of an
AGN. While the X-ray and IR observations provide robust evidence for an AGN,
the optical spectrum shows no evidence for the AGN, underscoring the need for
the penetrative power of mid-IR and X-ray observations in finding buried or
weak AGNs in this class of galaxy. Finally, the upper limit to the radio flux,
together with our previous X-ray and IR results, is consistent with the
scenario in which NGC 4178 harbors a deeply buried AGN accreting at a high
rate.


title: Gravitational Lensing by Spherical Lenses

abstract:
  In this work we introduced a new proposal to study the gravitational lensing
theory by spherical lenses, starting from its surface mass density $\Sigma(x)$
written in terms of a decreasing function $f$ of a dimensionless coordinate $x$
on the lens plane. The main result is the use of the function $f(x)$ to find
directly the lens properties, at the same time that the lens problem is
described by a first order differential equation which encodes all information
about the lens. SIS and NIS profiles are used as examples to find their
functions $f(x)$. Using the Poisson equation we find that the deflection angle
is directly proportional to $f(x)$, and therefore the lens equation can be
written in terms of the function and the parameters of the lens. The critical
and caustic curves, as well as image formation and magnification generated by
the lens are analyzed. As an example of this method, the properties of a lens
modeled by a NFW profile are determined. Altough the puntual mass is
spherically symmetric, its mass density is not continuous so that its $f(x)$
function is discussed in the Appendix A.


title: On Computability of Equilibria in Markets with Production

abstract:
  Although production is an integral part of the Arrow-Debreu market model,
most of the work in theoretical computer science has so far concentrated on
markets without production, i.e., the exchange economy. This paper takes a
significant step towards understanding computational aspects of markets with
production.
  We first define the notion of separable, piecewise-linear concave (SPLC)
production by analogy with SPLC utility functions. We then obtain a linear
complementarity problem (LCP) formulation that captures exactly the set of
equilibria for Arrow-Debreu markets with SPLC utilities and SPLC production,
and we give a complementary pivot algorithm for finding an equilibrium. This
settles a question asked by Eaves in 1975 of extending his complementary pivot
algorithm to markets with production.
  Since this is a path-following algorithm, we obtain a proof of membership of
this problem in PPAD, using Todd, 1976. We also obtain an elementary proof of
existence of equilibrium (i.e., without using a fixed point theorem),
rationality, and oddness of the number of equilibria. We further give a proof
of PPAD-hardness for this problem and also for its restriction to markets with
linear utilities and SPLC production. Experiments show that our algorithm runs
fast on randomly chosen examples, and unlike previous approaches, it does not
suffer from issues of numerical instability. Additionally, it is strongly
polynomial when the number of goods or the number of agents and firms is
constant. This extends the result of Devanur and Kannan (2008) to markets with
production.
  Finally, we show that an LCP-based approach cannot be extended to PLC
(non-separable) production, by constructing an example which has only
irrational equilibria.


title: CrowdGrader: Crowdsourcing the Evaluation of Homework Assignments

abstract:
  Crowdsourcing offers a practical method for ranking and scoring large amounts
of items. To investigate the algorithms and incentives that can be used in
crowdsourcing quality evaluations, we built CrowdGrader, a tool that lets
students submit and collaboratively grade solutions to homework assignments. We
present the algorithms and techniques used in CrowdGrader, and we describe our
results and experience in using the tool for several computer-science
assignments.
  CrowdGrader combines the student-provided grades into a consensus grade for
each submission using a novel crowdsourcing algorithm that relies on a
reputation system. The algorithm iterativerly refines inter-dependent estimates
of the consensus grades, and of the grading accuracy of each student. On
synthetic data, the algorithm performs better than alternatives not based on
reputation. On our preliminary experimental data, the performance seems
dependent on the nature of review errors, with errors that can be ascribed to
the reviewer being more tractable than those arising from random external
events. To provide an incentive for reviewers, the grade each student receives
in an assignment is a combination of the consensus grade received by their
submissions, and of a reviewing grade capturing their reviewing effort and
accuracy. This incentive worked well in practice.


title: Determining Top Quark Couplings at the LHC: Snowmass White Paper

abstract:
  Top quarks are a prime system for hunting for new physics. Nonetheless, two
decades on from their discovery few of their couplings have been measured to
high precision. We present an overview of current determinations and the
expected sensitivities with 300 fb-1 and 3000 fb-1 of 14 TeV LHC data. In
addition to direct limits on the top quark's renormalizable couplings to
Standard Model bosons, we also explore what bounds can be set on the
coefficients of higher-dimension operators, taking particular four-fermion
operators that do not interfere with QCD as a test case. Every coupling we
consider will benefit greatly from a dedicated study at the future LHC. Some
measurements, like the irrelevant operators, are systematics-limited and will
saturate in the near-term. Others, like the important ttbar+Higgs coupling,
involve rare processes and thus demand as much data as possible.


title:
The Lovasz-Bregman Divergence and connections to rank aggregation,
  clustering, and web ranking

abstract:
  We extend the recently introduced theory of Lovasz-Bregman (LB) divergences
(Iyer & Bilmes, 2012) in several ways. We show that they represent a distortion
between a 'score' and an 'ordering', thus providing a new view of rank
aggregation and order based clustering with interesting connections to web
ranking. We show how the LB divergences have a number of properties akin to
many permutation based metrics, and in fact have as special cases forms very
similar to the Kendall-$\tau$ metric. We also show how the LB divergences
subsume a number of commonly used ranking measures in information retrieval,
like the NDCG and AUC. Unlike the traditional permutation based metrics,
however, the LB divergence naturally captures a notion of "confidence" in the
orderings, thus providing a new representation to applications involving
aggregating scores as opposed to just orderings. We show how a number of
recently used web ranking models are forms of Lovasz-Bregman rank aggregation
and also observe that a natural form of Mallow's model using the LB divergence
has been used as conditional ranking models for the 'Learning to Rank' problem.


title: A Lyapunov type theorem from Kadison-Singer

abstract:
  Marcus, Spielman, and Srivastava recently solved the Kadison-Singer problem
by showing that if u_1, ..., u_m are column vectors in C^d such that \sum
u_iu_i^* = I, then a set of indices S \subseteq {1, ..., m} can be chosen so
that \sum_{i \in S} u_iu_i^* is approximately (1/2)I, with the approximation
good in operator norm to order \epsilon^{1/2} where \epsilon = \max \|u_i\|^2.
We extend their result to show that every linear combination of the matrices
u_iu_i^* with coefficients in [0,1] can be approximated in operator norm to
order \epsilon^{1/8} by a matrix of the form \sum_{i \in S} u_iu_i^*.


title:
Understanding Charge Transfer in Donor-Acceptor/Metal Systems: A
  Combined Theoretical and Experimental Study

abstract:
  We develop an effective potential approach for assessing the flow of charge
within a two-dimensional donor-acceptor/metal network based on core-level
shifts. To do so, we perform both density functional theory (DFT) calculations
and x-ray photoemission spectroscopy (XPS) measurements of the core-level
shifts for three different monolayers adsorbed on a Ag substrate. Specifically,
we consider perfluorinated pentacene (PFP), copper phthalocyanine (CuPc) and
their 1:1 mixture (PFP+CuPc) adsorbed on Ag(111).


title: Removing Colors 2k, 2k-1, and k

abstract:
  We prove that if a link admits non-trivial (2k+1)-colorings, with prime
2k+1>7, it also admits non-trivial (2k+1)-colorings not involving colors 2k,
2k-1, nor k.


title: The symmetry of Spin^c Dirac spectrums on Riemannian product manifolds

abstract:
  It is well-known that the spectrum of a $\text{spin}^{\mathbb{C}}$ Dirac
operator on a closed Riemannian $\text{spin}^{\mathbb{C}}$ manifold $M^{2k}$ of
dimension $2k$ for $k \in \mathbb{N}$ is symmetric. In this article, we prove
that over an odd-dimensional Riemannian product $M_{1}^{2p} \times
M_{2}^{2q+1}$ with a product $\text{spin}^{\mathbb{C}}$ structure for $p \geq
1, q \geq 0$, the spectrum of a $\text{spin}^{\mathbb{C}}$ Dirac operator given
by a product connection is symmetric if and only if either the
$\text{spin}^{\mathbb{C}}$ Dirac spectrum of $M_{2}^{2q+1}$ is symmetric or
$(e^{\frac{1}{2}c_{1}(L_{1})} \hat{A}(M_1))[M_{1}]=0$, where $L_1$ is the
associated line bundle for the given $\text{spin}^{\mathbb{C}}$ structure of
$M_1$.


title: Phase Transition to a Hairy Black Hole in Asymptotically Flat Spacetime

abstract:
  We discuss a phase transition of a Reissner-Nordstr\"om black hole to a hairy
black hole in asymptotically flat spacetime. The hair is due to a massive
charged scalar field. The no-hair theorem is evaded thanks to a derivative
coupling of the scalar field to the Einstein tensor. The resulting hairy
configuration is spherically symmetric. We solve the equations analytically
near the transition temperature and show that the hair is concentrated near the
horizon decaying exponentially away from it.


title:
Ensemble of Distributed Learners for Online Classification of Dynamic
  Data Streams

abstract:
  We present an efficient distributed online learning scheme to classify data
captured from distributed, heterogeneous, and dynamic data sources. Our scheme
consists of multiple distributed local learners, that analyze different streams
of data that are correlated to a common event that needs to be classified. Each
learner uses a local classifier to make a local prediction. The local
predictions are then collected by each learner and combined using a weighted
majority rule to output the final prediction. We propose a novel online
ensemble learning algorithm to update the aggregation rule in order to adapt to
the underlying data dynamics. We rigorously determine a bound for the worst
case misclassification probability of our algorithm which depends on the
misclassification probabilities of the best static aggregation rule, and of the
best local classifier. Importantly, the worst case misclassification
probability of our algorithm tends asymptotically to 0 if the misclassification
probability of the best static aggregation rule or the misclassification
probability of the best local classifier tend to 0. Then we extend our
algorithm to address challenges specific to the distributed implementation and
we prove new bounds that apply to these settings. Finally, we test our scheme
by performing an evaluation study on several data sets. When applied to data
sets widely used by the literature dealing with dynamic data streams and
concept drift, our scheme exhibits performance gains ranging from 34% to 71%
with respect to state of the art solutions.


title:
Locally Compact Separable Abelian Group Actions on Factors with the
  Rohlin Property

abstract:
  We show a classification theorem for locally compact separable abelain group
actions on factorsw with the Rohlin property. This is a generalization of
Masuda and Tomatsu's work.


title: Electrical current in Sinai billiards under general small forces

abstract:
  The Lorentz gas of $\mathbb{Z}^2$-periodic scatterers (or the so called Sinai
billiards) can be used to model motion of electrons on an ionized medal. We
investigate the linear response for the system under various external forces
(during both the flight and the collision). We give some characterizations
under which the forced system is time-reversible, and derive an estimate of the
electrical current generated by the forced system. Moreover, applying Pesin
entropy formula and Young dimension formula, we get several characterizations
of the non-equilibrium steady state of the forced system.


title:
Level alignment of a prototypical photocatalytic system: Methanol on
  TiO2(110)

abstract:
  Photocatalytic and photovoltaic activity depends on the optimal alignment of
electronic levels at the molecule/semiconductor interface. Establishing level
alignment experimentally is complicated by the uncertain chemical identity of
the surface species. We address the assignment of the occupied and empty
electronic levels for the prototypical photocatalytic system of methanol on a
rutile TiO2 (110) surface. Using many-body quasiparticle (QP) techniques we
show that the frontier levels measured in ultraviolet photoelectron and two
photon photoemission spectroscopy experiments can be assigned with confidence
to the molecularly chemisorbed methanol, rather than its decomposition product,
the methoxy species. We find the highest occupied molecular orbital (HOMO) of
the methoxy species is much closer to the valence band maximum, suggesting why
it is more photocatalytically active than the methanol molecule. We develop a
general semi-quantitative model for predicting many-body QP energies based on
the appropriate description of electronic screening within the bulk, molecular
or vacuum regions of the wavefunctions at molecule/semiconductor interfaces.


title: Rees Algebras of Truncations of Complete Intersections

abstract:
  In this paper we describe the defining equations of the Rees algebra and the
special fiber ring of a truncation I of a complete intersection ideal in a
polynomial ring over a field with homogeneous maximal ideal m. To describe
explicitly the Rees algebra R(I) in terms of generators and relations we map
another Rees ring R(M) onto it, where M is the direct sum of powers of m. We
compute a Groebner basis of the ideal defining R(M). It turns out that the
normal domain R(M) is a Koszul algebra and from this we deduce that in many
instances R(I) is a Koszul algebra as well.


title: R-Score: Reputation-based Scoring of Research Groups

abstract:
  To manage the problem of having a higher demand for resources than
availability of funds, research funding agencies usually rank the major
research groups in their area of knowledge. This ranking relies on a careful
analysis of the research groups in terms of their size, number of PhDs
graduated, research results and their impact, among other variables. While
research results are not the only variable to consider, they are frequently
given special attention because of the notoriety they confer to the researchers
and the programs they are affiliated with. In here we introduce a new metric
for quantifying publication output, called R-Score for reputation-based score,
which can be used in support to the ranking of research groups or programs. The
novelty is that the metric depends solely on the listings of the publications
of the members of a group, with no dependency on citation counts. R-Score has
some interesting properties: (a) it does not require access to the contents of
published material, (b) it can be curated to produce highly accurate results,
and (c) it can be naturally used to compare publication output of research
groups (e.g., graduate programs) inside a same country, geographical area, or
across the world. An experiment comparing the publication output of 25 CS
graduate programs from Brazil suggests that R-Score can be quite useful for
providing early insights into the publication patterns of the various research
groups one wants to compare.


title:
The graphene sheet versus the 2DEG: a relativistic Fano spin-filter via
  STM and AFM tips

abstract:
  We explore theoretically the density of states (LDOS) probed by an STM tip of
2D systems hosting an adatom and a subsurface impurity,both capacitively
coupled to AFM tips and traversed by antiparallel magnetic fields. Two kinds of
setups are analyzed, a monolayer of graphene and a two-dimensional electron gas
(2DEG). The AFM tips set the impurity levels at the Fermi energy, where two
contrasting behaviors emerge: the Fano factor for the graphene diverges, while
in the 2DEG it approaches zero. As result, the spin-degeneracy of the LDOS is
lifted exclusively in the graphene system, in particular for the asymmetric
regime of Fano interference. The aftermath of this limit is a counterintuitive
phenomenon, which consists of a dominant Fano factor due to the subsurface
impurity even with a stronger STM-adatom coupling. Thus we find a full
polarized conductance, achievable just by displacing vertically the position of
the STM tip. To the best knowledge, our work is the first to propose the Fano
effect as the mechanism to filter spins in graphene. This feature arises from
the massless Dirac electrons within the band structure and allows us to employ
the graphene host as a relativistic Fano spin-filter.


title: Pragmatic View of Short-Baseline Neutrino Oscillations

abstract:
  We present the results of global analyses of short-baseline neutrino
oscillation data in 3+1, 3+2 and 3+1+1 neutrino mixing schemes. We show that
the data do not allow us to abandon the simplest 3+1 scheme in favor of the
more complex 3+2 and 3+1+1 schemes. We present the allowed region in the 3+1
parameter space, which is located at $\Delta{m}^2_{41}$ between 0.82 and 2.19
$\text{eV}^2$ at $3\sigma$. The case of no oscillations is disfavored by about
$6\sigma$, which decreases dramatically to about $2\sigma$ if the LSND data are
not considered. Hence, new high-precision experiments are needed to check the
LSND signal.


title: Coherence and Other Properties of Sheaves in the Kohn Algorithm

abstract:
  In the smooth case, we prove quasi-flasqueness for the sheaves of all
subelliptic multipliers as well as at each of the steps of the Kohn algorithm
on a pseudoconvex domain in $\C^n.$ We use techniques by Jean-Claude Tougeron
to show that if the domain has a real-analytic defining function, the modified
Kohn algorithm involving generating ideals and taking real radicals only in the
ring of real-analytic germs yields quasi-coherent sheaves. This sharpens a
result obtained by J. J. Kohn in 1979.


title: On Quantum Theory

abstract:
  Quantum theory is a well-defined local theory with a clear interpretation. No
"measurement problem" or any other foundational matters are waiting to be
settled.


title:
Spin Dynamics in Graphene and Graphene like Nanocarbon Doped with
  Nitrogen the ESR Analysis

abstract:
  Nano engineered spin degree of freedom in carbon system may offer desired
exchange coupling with optimum spin orbit interaction which is essential, to
construct solid state qubits, for fault tolerant quantum computation. The
purpose of this communication is to analyze spin dynamics of, basically, four
types of systems, (i) Graphene (system with inversion symmetry), (ii) Graphene
like nanocarbons (GNCs, broken inversion symmetry and heterostructure, sp2 and
sp3, environment), and (iii) their nitrogen doped derivatives. The spin
transport data was obtained using the electron spin resonance spectroscopy
(ESR) technique, carried out over 123 to 473K temperature range. Analysis of
shape, linewidths of dispersion derivatives,, and g factor anisotropy has been
carried out. Spin parameters such as, spin spin relaxation time, spin lattice
relaxation time, spin flip parameter,spin relaxation rate,spin, momentum
relaxation rate,pseudo chemical potential, density of states, effective
magnetic moment, spin concentration, defect concentration, and Pauli
susceptibility, has been estimated, and examined for their temperature as well
as interdependence. Details of the analysis are presented. The quantitative
study underlined the following facts: (i) by and large, spin dynamics in
Graphene and GNCs is significantly different, (ii) transport of spin behaves in
opposite fashion, after doping nitrogen, in both the systems, (iii) reduction
in the magnetization has been observed for both GNCs and Graphene, after doping
nitrogen, (iv) hyperfine interactions have been observed in all classes of
systems except in GNCs, (v) nitrogen doped GNCs seems to be appropriate for
qubit designing.


title:
Searching for gravitational-wave transients with a qualitative signal
  model: seedless clustering strategies

abstract:
  Gravitational-wave bursts are observable as bright clusters of pixels in
spectrograms of strain power. Clustering algorithms can be used to identify
candidate gravitational-wave events. Clusters are often identified by grouping
together seed pixels in which the power exceeds some threshold. If the
gravitational-wave signal is long-lived, however, the excess power may be
spread out over many pixels, none of which are bright enough to become seeds.
Without seeds, the problem of detection through clustering becomes more
complicated. In this paper we investigate seedless clustering algorithms in
searches for long-lived narrowband gravitational-wave bursts. Using four
astrophysically motivated test waveforms, we compare a seedless clustering
algorithm to two algorithms using seeds. We find that the seedless algorithm
can detect gravitational-wave signals (at fixed false-alarm and false-dismissal
rate) at distances between 150-200% greater than those achieved with the
seed-based clustering algorithms, corresponding to significantly increased
detection volumes: 420-740%. This improvement in sensitivity may extend the
reach of second-generation detectors such as Advanced LIGO and Advanced Virgo
deeper into astrophysically interesting distances.


title: On series of free $R$-diagonal operators

abstract:
  For a series of free $R$-diagonal operators, we prove an analogue of the
three series theorem. We show that a series of free $R$-diagonal operators
converges almost uniformly if and if two numerical series converge.


title:
Solving Multiple-Block Separable Convex Minimization Problems Using
  Two-Block Alternating Direction Method of Multipliers

abstract:
  In this paper, we consider solving multiple-block separable convex
minimization problems using alternating direction method of multipliers (ADMM).
Motivated by the fact that the existing convergence theory for ADMM is mostly
limited to the two-block case, we analyze in this paper, both theoretically and
numerically, a new strategy that first transforms a multi-block problem into an
equivalent two-block problem (either in the primal domain or in the dual
domain) and then solves it using the standard two-block ADMM. In particular, we
derive convergence results for this two-block ADMM approach to solve
multi-block separable convex minimization problems, including an improved
O(1/\epsilon) iteration complexity result. Moreover, we compare the numerical
efficiency of this approach with the standard multi-block ADMM on several
separable convex minimization problems which include basis pursuit, robust
principal component analysis and latent variable Gaussian graphical model
selection. The numerical results show that the multiple-block ADMM, although
lacks theoretical convergence guarantees, typically outperforms two-block
ADMMs.


title:
Exact Analytical Solution of the N-dimensional Radial Schrodinger
  Equation with Pseudoharmonic Potential via Laplace Transform Approach

abstract:
  The second order $N$-dimensional Schr\"odinger equation with pseudoharmonic
potential is reduced to a first order differential equation by using the
Laplace transform approach and exact bound state solutions are obtained using
convolution theorem. Some special cases are verified and variation of energy
eigenvalues $E_n$ as a function of dimension $N$ are furnished. To give an
extra depth of this letter, present approach is also briefly investigated for
generalized Morse potential as an example.


title:
Evolution of Light-Like Wilson Loops with a Self-Intersection in Loop
  Space

abstract:
  Recently, we proposed a general evolution equation for single quadrilateral
Wilson loop on the light-cone. In present work, we study the energy evolution
of a combination of two such loops that partially overlap or have a
self-intersection. We show that, for a class of geometric variations, then
evolution is consistent with our previous conjecture, and we are able to handle
the intricacies associated with the self-intersections and overlaps. This way,
a step forward is made towards the understanding of loop space, with the hope
of studying more complicated structures appearing in phenomenological relevant
objects, such as parton distributions.


title:
The Jastrow antisymmetric geminal power in Hilbert space: theory,
  benchmarking, and application to a novel transition state

abstract:
  The Jastrow-modified antisymmetric geminal power (JAGP) ansatz in Hilbert
space successfully overcomes two key failings of other pairing theories, namely
a lack of inter-pair correlations and a lack of multiple resonance structures,
while maintaining a polynomially scaling cost, variational energies, and size
consistency. Here we present efficient quantum Monte Carlo algorithms that
evaluate and optimize the JAGP energy for a cost that scales as the fifth power
of the system size. We demonstrate the JAGP's ability to describe both static
and dynamic correlation by applying it to bond stretching in H2O, C2, and N2 as
well as to a novel, multi-reference transition state of ethene. JAGP's accuracy
in these systems outperforms even the most sophisticated single-reference
methods and approaches that of exponentially-scaling active space methods.


title:
Spin Squeezing of Superposition of Biaxial State and two qubit Bell
  State

abstract:
  In this study we investigate the spin squeezing in superposition of a Biaxial
state [1,2] and Bell state. Numerical and analytical solutions for the length
of mean spin, mean spin direction and spin squeezing are given. It is shown
that both the mean spin direction and spin squeezing parameter are determined
by the coefficients of superposition and the relative phase.


title: A multi-level solver for Gaussian constrained CMB realizations

abstract:
  We present a multi-level solver for drawing constrained Gaussian realizations
or finding the maximum likelihood estimate of the CMB sky, given noisy sky maps
with partial sky coverage. The method converges substantially faster than
existing Conjugate Gradient (CG) methods for the same problem. For instance,
for the 143 GHz Planck frequency channel, only 3 multi-level W-cycles result in
an absolute error smaller than 1 microKelvin in any pixel. Using 16 CPU cores,
this translates to a computational expense of 6 minutes wall time per
realization, plus 8 minutes wall time for a power spectrum-dependent
precomputation. Each additional W-cycle reduces the error by more than an order
of magnitude, at an additional computational cost of 2 minutes. For comparison,
we have never been able to achieve similar absolute convergence with
conventional CG methods for this high signal-to-noise data set, even after
thousands of CG iterations and employing expensive preconditioners. The solver
is part of the Commander 2 code, which is available with an open source license
at http://commander.bitbucket.org/.


title: cK\cent, a model to reason on learners' conceptions

abstract:
  Understanding learners' understanding is a key requirement for an efficient
design of teaching situations and learning environments, be they digital or
not. This keynote outlines the modeling framework cK\cent (conception, knowing,
concept) created with the objective to respond to this requirement, with the
additional ambition to build a bridge between research in mathematics education
and research in educational technology. After an introduction of the rationale
of cK\cent, some illustrations are presented. Then follow comments on cK\cent
and learning. The conclusion evokes key research issues raised by the use of
this modeling framework.


title: Pseudo-critical clusterization in nuclear multifragmentation

abstract:
  In this contribution we show that the biggest fragment charge distribution in
central collisions of Xe+Sn leading to multifragmentation is an admixture of
two asymptotic distributions observed for the lowest and highest bombarding
energies. The evolution of the relative weights of the two components with
bombarding energy is shown to be analogous to that observed as a function of
time for the largest cluster produced in irreversible aggregation for a finite
system. We infer that the size distribution of the largest fragment in nuclear
multifragmentation is also characteristic of the time scale of the process,
which is largely determined by the onset of radial expansion in this energy
range.


title: Sequential fissions of heavy nuclear systems

abstract:
  In Xe+Sn central collisions from 12 to 20 MeV/A measured with the INDRA
4$\pi$ multidetector, the three-fragment exit channel occurs with a significant
cross section. In this contribution, we show that these fragments arise from
two successive binary splittings of a heavy composite system. Strong Coulomb
proximity effects are observed in the three-fragment final state. By comparison
with Coulomb trajectory calculations, we show that the time scale between the
consecutive break-ups decreases with increasing bombarding energy, becoming
compatible with quasi-simultaneous multifragmentation above 18 MeV/A.


title: Non-commutative Dp-Brane in General Background Fields

abstract:
  We investigate non-commutativity of open strings, attached to a D$p$-brane,
in the presence of the linear dilaton, tachyon, U(1) gauge field as well as
constant anti-symmetric $B$-field backgrounds. Non-commutativity parameter,
open string metric and some special cases will be studied. Mode-dependent
non-commutativity, inspired by the tachyon field, will be discussed in detail.


title:
Enhancing Secrecy with Multi-Antenna Transmission in Wireless Ad Hoc
  Networks

abstract:
  We study physical-layer security in wireless ad hoc networks and investigate
two types of multi-antenna transmission schemes for providing secrecy
enhancements. To establish secure transmission against malicious eavesdroppers,
we consider the generation of artificial noise with either sectoring or
beamforming. For both approaches, we provide a statistical characterization and
tradeoff analysis of the outage performance of the legitimate communication and
the eavesdropping links. We then investigate the networkwide secrecy throughput
performance of both schemes in terms of the secrecy transmission capacity, and
study the optimal power allocation between the information signal and the
artificial noise. Our analysis indicates that, under transmit power
optimization, the beamforming scheme outperforms the sectoring scheme, except
for the case where the number of transmit antennas are sufficiently large. Our
study also reveals some interesting differences between the optimal power
allocation for the sectoring and beamforming schemes.


title:
Spin-chain magnetism and uniform Dzyaloshinsky-Moriya anisotropy in
  BaV$_3$O$_8$

abstract:
  We report on the microscopic magnetic model of a spin-1/2 magnet
BaV$_3$O$_8$. In contrast to earlier phenomenological analysis, our
density-functional band-structure calculations combined with quantum
Monte-Carlo simulations establish a relatively simple and non-frustrated model
of weakly coupled spin chains with the intrachain coupling of $J\sim$ 38 K and
the Neel temperature of $T_N\sim$ 6 K, both in excellent agreement with the
experiment. The intrachain coupling between the spin-1/2 V$^{+4}$ ions takes
place via two contiguous V$^{+5}$O$_4$ tetrahedra forming an extended
superexchange pathway with the V$^{+4}$--V$^{+4}$ distance of 7.44 A.
Surprisingly, this pathway is preferred over shorter V$^{+4}$--V$^{+4}$
connections, owing to peculiarities in the interacting orbitals of the magnetic
V$^{+4}$ ions and V$^{+5}$ ions that are non-magnetic, but feature low-lying
$3d$ states contributing to the superexchange process. We also note that the
crystal structure of BaV$_3$O$_8$ supports the long-sought uniform arrangement
of Dzyaloshinsky-Moriya (DM) couplings on a spin-1/2 chain. While our
calculations yield only a weak DM anisotropy in BaV$_3$O$_8$, the crystal
structure of this compound provides a suitable framework for the search of spin
chains with the uniform DM anisotropy in other compounds of the vanadate
family.


title: The Korteweg-de Vries Equation

abstract:
  Two page encyclopedic article about the Korteweg-de Vries equation covering
historical perspective, solitary wave and periodic solutions, modern
developments, properties and applications, and further reading.


title: Current experimental bounds on stop mass in natural SUSY

abstract:
  Motivated by the recent progress of direct search for the productions of stop
pair and sbottom pair at the LHC, we examine the constraints of the search
results on the stop ($\tilde{t}_1$) mass in natural SUSY. We first scan the
parameter space of natural SUSY in the framework of MSSM, considering the
constraints from the Higgs mass, B-physics and electroweak precision
measurements. Then in the allowed parameter space we perform a Monte Carlo
simulation for stop pair production followed by $\tilde{t}_{1} \to t
\tilde{\chi}_{1}^{0}$ or $\tilde{t}_{1} \to b \tilde{\chi}_{1}^{+}$ and sbottom
pair production followed by $\tilde{b}_{1} \to b \tilde{\chi}_{1}^{0}$ or
$\tilde{b}_{1} \to t \tilde{\chi}_{1}^{-}$. Using the combined results of ATLAS
with 20.1 fb$^{-1}$ from the search of $\ell+{\rm jets}+\slashed E_{T}$,
hadronic $t\bar{t}+\slashed E_{T}$ and $2b+\slashed E_{T}$, we find that a stop
lighter than 600 GeV can be excluded at 95% CL in this scenario.


title:
Stability of viscous fluid in Bianchi type-VI model with cosmological
  constant

abstract:
  In this paper, we investigate Bianchi type-$VI$ cosmological model for the
universe filled with dark energy and viscous fluid in the presence of
cosmological constant. Also, we show accelerating expansion of the universe by
drawing volume scale, pressure and energy density versus cosmic time. In order
to solve the Einstein field equations, we assume the expansion scalar is
proportional to a component of the shear tensor. Therefore, we obtain the
directional scale factors and show the EOS parameter crosses over phantom
divided-line.


title:
Bismut formulae and applications for stochastic (functional)
  differential equations driven by fractional Brownian motions

abstract:
  By using Malliavin calculus, Bismut derivative formulae are established for a
class of stochastic (functional) differential equations driven by fractional
Brownian motions. As applications, Harnack type inequalities and strong Feller
property are presented.


title: Anomaly Detections in Internet traffic Using Empirical Measures

abstract:
  Introducing Internet traffic anomaly detection mechanism based on large
deviations results for empirical measures. Using past traffic traces we
characterize network traffic during various time-of-day intervals, assuming
that it is anomaly-free. Throughout, we compare the two approaches presenting
their advantages and disadvantages to identify and classify temporal network
anomalies. We also demonstrate how our framework can be used to monitor traffic
from multiple network elements in order to identify both spatial and temporal
anomalies. We validate our techniques by analyzing real traffic traces with
time-stamped anomalies.


title:
Demonstration of surface transport in a hybrid Bi2Se3/Bi2Te3
  heterostructure

abstract:
  In spite of much work on topological insulators (TIs), systematic experiments
for TI/TI heterostructures remain absent. We grow a high quality
heterostructure containing single quintuple layer (QL) of Bi2Se3 on 19 QLs of
Bi2Te3 and compare its transport properties with 20 QLs Bi2Se3 and 20 QLs
Bi2Te3. All three films are grown on insulating sapphire (0001) substrates by
molecular beam epitaxy (MBE). In situ angle-resolved photoemission spectroscopy
(ARPES) provides direct evidence that the surface state of 1 QL Bi2Se3 / 19 QLs
Bi2Te3 heterostructure is similar to the surface state of the 20 QLs Bi2Se3 and
different with that of the 20 QLs Bi2Te3. In ex situ transport measurements,
the observed linear magnetoresistance (MR) and weak antilocalization (WAL) of
the hybrid heterostructure are similar to that of the pure Bi2Se3 film and not
the Bi2Te3 film. This suggests that the single Bi2Se3 QL layer on top of 19 QLs
Bi2Te3 dominates its transport properties.


title:
Examples of Application of Nonparametric Information Geometry to
  Statistical Physics

abstract:
  We review a nonparametric version of Amari's Information Geometry in which
the set of positive probability densities on a given sample space is endowed
with an atlas of charts to form a differentiable manifold modeled on Orlicz
Banach spaces. This nonparametric setting is used to discuss the setting of
typical problems in Machine Learning and Statistical Physics, such as relaxed
optimization, Kullback-Leibler divergence, Boltzmann entropy, Boltzmann
equation


title: New Scotogenic Model of Neutrino Mass with $U(1)_D$ Gauge Interaction

abstract:
  We propose a new realization of the one-loop radiative model of neutrino mass
generated by dark matter (scotogenic), where the particles in the loop have an
additional $U(1)_D$ gauge symmetry, which may be exact or broken to $Z_2$. This
model is relevant to a number of astrophysical observations, including AMS-02
and the dark matter distribution in dwarf galactic halos.


title:
Stability and spectral convergence of Fourier method for nonlinear
  problems. On the shortcomings of the 2/3 de-aliasing method

abstract:
  The high-order accuracy of Fourier method makes it the method of choice in
many large scale simulations. We discuss here the stability of Fourier method
for nonlinear evolution problems, focusing on the two prototypical cases of the
inviscid Burgers' equation and the multi-dimensional incompressible Euler
equations. The Fourier method for such problems with quadratic nonlinearities
comes in two main flavors. One is the spectral Fourier method. The other is the
2/3 pseudo-spectral Fourier method, where one removes the highest 1/3 portion
of the spectrum; this is often the method of choice to maintain the balance of
quadratic energy and avoid aliasing errors. Two main themes are discussed in
this paper. First, we prove that as long as the underlying exact solution has a
minimal C^{1+\alpha} spatial regularity, then both the spectral and the 2/3
pseudo-spectral Fourier methods are stable. Consequently, we prove their
spectral convergence for smooth solutions of the inviscid Burgers equation and
the incompressible Euler equations. On the other hand, we prove that after a
critical time at which the underlying solution lacks sufficient smoothness,
then both the spectral and the 2/3 pseudo-spectral Fourier methods exhibit
nonlinear instabilities which are realized through spurious oscillations. In
particular, after shock formation in inviscid Burgers' equation, the total
variation of bounded (pseudo-) spectral Fourier solutions must increase with
the number of increasing modes and we stipulate the analogous situation occurs
with the 3D incompressible Euler equations: the limiting Fourier solution is
shown to enforce L^2-energy conservation, and the contrast with energy
dissipating Onsager solutions is reflected through spurious oscillations.


title: Edge-detection applied to moving sand dunes on Mars

abstract:
  Here we discuss the application of an edge detection filter, the Sobel filter
of GIMP, to the recently discovered motion of some sand dunes on Mars. The
filter allows a good comparison of an image HiRISE of 2007 and an image of 1999
recorded by the Mars Global Surveyor of the dunes in the Nili Patera caldera,
measuring therefore the motion of the dunes on a longer period of time than
that previously investigated.


title:
Triple-helical collagen hydrogels via covalent aromatic
  functionalization with 1,3-Phenylenediacetic acid

abstract:
  Chemical crosslinking of collagen is a general strategy to reproduce
macroscale tissue properties in physiological environment. However,
simultaneous control of protein conformation, material properties and
biofunctionality is highly challenging with current synthetic strategies.
Consequently, the potentially-diverse clinical applications of collagen-based
biomaterials cannot be fully realised. In order to establish defined
biomacromolecular systems for mineralised tissue applications, type I collagen
was functionalised with 1,3-Phenylenediacetic acid (Ph) and investigated at the
molecular, macroscopic and functional levels. Preserved triple helix
conformation was observed in obtained covalent networks via ATR-FTIR and WAXS,
while network crosslinking degree could be adjusted based on specific reaction
conditions. Decreased swelling ratio and increased thermo-mechanical properties
were observed compared to state of-the-art carbodiimide (EDC)-crosslinked
collagen controls, likely related to the intermolecular covalent incorporation
of the aromatic segment. Ph crosslinked hydrogels displayed nearly intact
material integrity and only a slight mass decrease following 1-week incubation
in either PBS or simulated body fluid (SBF), in contrast to EDC crosslinked
collagen. Furthermore, FTIR, SEM and EDS revealed deposition of a
calcium-phosphate phase on SBF-retrieved samples, whereby an increased calcium
phosphate ratio was observed in hydrogels with higher Ph content. 72-hour
material extracts were well tolerated by L929 mouse fibroblasts, whereby cell
confluence and metabolic activity (MTS assay) were comparable to those of cells
cultured in cell culture medium (positive control). In light of their
controlled structure-function properties, these biocompatible collagen
hydrogels represent attractive material systems for potential mineralised
tissue applications.


title:
Peer Pressure Shapes Consensus, Leadership, and Innovations in Social
  Groups

abstract:
  What is the effect of the combined direct and indirect social influences-peer
pressure (PP)-on a social groups collective decisions? We present a model that
captures PP as a function of the socio-cultural distance between individuals in
a social group. Using this model and empirical data from 15 real-world social
networks we found that the PP level determines how fast a social group reaches
consensus. More importantly, the levels of PP determine the leaders who can
achieve full control of their social groups. PP can overcome barriers imposed
upon a consensus by the existence of tightly connected communities with local
leaders or the existence of leaders with poor cohesiveness of opinions. A
moderate level of PP is also necessary to explain the rate at which innovations
diffuse through a variety of social groups.


title:
Convergence to Equilibrium States for Fluid Models of Many-server Queues
  with Abandonment

abstract:
  Fluid models have become an important tool for the study of many-server
queues with general service and patience time distributions. The equilibrium
state of a fluid model has been revealed by Whitt (2006) and shown to yield
reasonable approximations to the steady state of the original stochastic
systems. However, it remains an open question whether the solution to a fluid
model converges to the equilibrium state and under what condition. We show in
this paper that the convergence holds under a mild condition. Our method builds
on the framework of measure-valued processes developed in Zhang (2013), which
keeps track of the remaining patience and service times.


title:
Emerging magnetism and electronic phase separation at titanate
  interfaces

abstract:
  The emergence of magnetism in otherwise nonmagnetic compounds and its
underlying mechanisms have become the subject of intense research. Here we
demonstrate that the nonmagnetic oxygen vacancies are responsible for an
unconventional magnetic state common for titanate interfaces and surfaces.
Using an effective multiorbital modelling, we find that the presence of
localized vacancies leads to an interplay of ferromagnetic order in the
itinerant t2g band and complex magnetic oscillations in the
orbitally-reconstructed eg-band, which can be tuned by gate fields at oxide
interfaces. The magnetic phase diagram includes highly fragmented regions of
stable and phase-separated magnetic states forming beyond nonzero critical
defect concentrations.


title: Polynomial problems of the Casas-Alvero type

abstract:
  We establish necessary and sufficient conditions for an arbitrary polynomial
of degree $n$, especially with only real roots, to be trivial, i.e. to have the
form a(x-b)^n. To do this, we derive new properties of polynomials and their
roots. In particular, it concerns new bounds and genetic sum's representations
of the Abel -Goncharov interpolation polynomials. Moreover, we prove the
Sz.-Nagy type identities, the Laguerre and Obreshkov-Chebotarev type
inequalities for roots of polynomials and their derivatives. As applications
these results are associated with the known problem, conjectured by Casas-
Alvero in 2001, which says, that any complex univariate polynomial, having a
common root with each of its non-constant derivative must be a power of a
linear polynomial. We investigate particular cases of the problem, when the
conjecture holds true or, possibly, is false.


title: Evolution Theory of Self-Evolving Autonomous Problem Solving Systems

abstract:
  The present study gives a mathematical framework for self-evolution within
autonomous problem solving systems. Special attention is set on universal
abstraction, thereof generation by net block homomorphism, consequently
multiple order solving systems and the overall decidability of the set of the
solutions. By overlapping presentation of nets new abstraction relation among
nets is formulated alongside with consequent alphabetical net block renetting
system proportional to normal forms of renetting systems regarding the
operational power. A new structure in self-evolving problem solving is
established via saturation by groups of equivalence relations and iterative
closures of generated quotient transducer algebras over the whole evolution.


title:
Relativistic and non-relativistic quantum Brownian motion in an
  anisotropic dissipative medium

abstract:
  Using a minimal-coupling-scheme we investigate the quantum Brownian motion of
a particle in an anisotropic-dissipative-medium under the influence of an
arbitrary potential in both relativistic and non-relativistic regimes. A
general quantum Langevin equation is derived and explicit expressions for
quantum-noise and dynamical variables of the system are obtained. The equations
of motion for the canonical variables are solved explicitly and an expression
for the radiation-reaction of a charged particle in the presence of a
dissipative-medium is obtained. Some examples are given to elucidate the
applicability of this approach.


title:
On the spectrum of an "even" periodic Schroedinger operator with a
  rational magnetic flux

abstract:
  We study the Schr\"odinger operator on $L_2(\mathbb R^3)$ with periodic
variable metric, and periodic electric and magnetic fields. It is assumed that
the operator is reflection symmetric and the (appropriately defined) flux of
the magnetic field is rational. Under these assumptions it is shown that the
spectrum of the operator is absolutely continuous. Previously known results on
absolute continuity for periodic operators were obtained for the zero magnetic
flux.


title: Trident Pair Production in Colliding Bright X-ray Laser Beams

abstract:
  The magnificent development of strong X-ray lasers motivates the advancement
of pair production process studies into higher laser frequency region. In this
paper, a resonant electron-positron pair production process with the absorption
of two X-ray photons is considered in the impact of an energetic electron at
the overlap region of two colliding X-ray laser beams. Laser-dressed QED method
is justified to tackle the complexity of the corresponding multiple Feynman
diagrams calculation. The dependence of the production rate as well as the
positron energy distribution on the relative angles among the directions of the
two laser wave vectors and the incoming electron momentum is revealed. It is
shown that the non-plane wave laser field configuration arouses novel features
in the pair production process compared to the plane-wave case.


title: The Riemann-Roch theorem for graphs and the rank in complete graphs

abstract:
  The paper by M. Baker and S. Norine in 2007 introduced a new parameter on
configurations of graphs and gave a new result in the theory of graphs which
has an algebraic geometry flavour. This result was called Riemann-Roch formula
for graphs since it defines a combinatorial version of divisors and their ranks
in terms of configuration on graphs. The so called chip firing game on graphs
and the sandpile model in physics play a central role in this theory.
  In this paper we give a presentation of the theorem of Baker and Norine in
purely combinatorial terms, which is more accessible and shorter than the
original one. An algorithm for the determination of the rank of configurations
is also given for the complete graph $K_n$. This algorithm has linear
arithmetic complexity. The analysis of number of iterations in a less optimized
version of this algorithm leads to an apparently new parameter which we call
the prerank. This parameter and the classical area parameter provide an
alternative description to some well known $q,t$-Catalan numbers. Restricted to
a natural subset of configurations, the two natural statistics degree and rank
in Riemann-Roch formula lead to a distribution which is described by a
generating function which, up to a change of variables, is a symmetric fraction
involving two copies of Carlitz q-analogue of the Catalan numbers.


title:
A Novel Method for Image Integrity Authentication Based on Fixed Point
  Theory

abstract:
  Based on fixed point theory, this paper proposes a simple but efficient
method for image integrity authentication, which is different from Digital
Signature and Fragile Watermarking. By this method, any given image can be
transformed into a fixed point of a well-chosen function, which can be
constructed with periodic functions. The authentication can be realized due to
the fragility of the fixed points. The experiments show that 'Fixed Point
Image' performs well in security, transparence, fragility and tampering
localization.


title:
ReBe2B5O11 (Re = Y, Gd)- A Series of Rare Earth Beryllium Borates as
  Deep-Ultraviolet Nonlinear Optical Materials

abstract:
  The rapid developments of the deep-ultraviolet (deep-UV) laser science and
technology urgently demand the nonlinear optical crystals which have large band
gap enough to transmit the deep-UV light. Herein, we synthesized a series of
new rare earth beryllium borates: ReBe2B5O11 (Re = Y, Gd). The structures of
all these materials, for both alpha and beta phases, are featured by a novel
platelike infinite superlayer [Be2B5O11]3-. Each [Be2B5O11]3- layer is further
connected to the neighbor superlayer through Re3+ cations coordinating with O
atoms. The beta-ReBe2B5O11 (Re=Y, Gd) have relatively large nonlinear optical
coefficients and short UV cut-off wavelength below 200nm. Our investigations
indicate that they are promising deep-UV NLO crystals.


title:
Supervariable approach to nilpotent symmetries of a couple of N = 2
  supersymmetric quantum mechanical models

abstract:
  We derive the on-shell as well as off-shell nilpotent supersymmetric (SUSY)
symmetry transformations for the N = 2 SUSY quantum mechanical model of a one
(0 + 1)-dimensional (1D) free SUSY particle by exploiting the SUSY invariant
restrictions (SUSYIRs) on the (anti-)chiral supervariables of the SUSY theory
that is defined on a (1, 2)-dimensional supermanifold (parametrized by a
bosonic variable t and a pair of Grassmannian variables \theta and \bar\theta
with \theta^2 = \bar\theta^2 = 0, \theta\bar\theta + \bar\theta\theta = 0).
Within the framework of our novel approach, we express the Lagrangian and
conserved SUSY charges in terms of the (anti-)chiral supervariables to
demonstrate the SUSY invariance of the Lagrangian as well as the nilpotency of
the SUSY conserved charges in a simple manner. Our approach has the potential
to be generalized to the description of other N = 2 SUSY quantum mechanical
systems with physically interesting potential functions. To corroborate the
above assertion, we apply our method to derive the N = 2 continuous and
nilpotent SUSY transformations for one of the simplest interacting SUSY system
of a 1D harmonic oscillator.


title: Monitoring with uncertainty

abstract:
  We discuss the problem of runtime verification of an instrumented program
that misses to emit and to monitor some events. These gaps can occur when a
monitoring overhead control mechanism is introduced to disable the monitor of
an application with real-time constraints. We show how to use statistical
models to learn the application behavior and to "fill in" the introduced gaps.
Finally, we present and discuss some techniques developed in the last three
years to estimate the probability that a property of interest is violated in
the presence of an incomplete trace.


title: Combinatorial Abstractions of Dynamical Systems

abstract:
  Formal verification has been successfully developed in computer science for
verifying combinatorial classes of models and specifications. In like manner,
formal verification methods have been developed for dynamical systems. However,
the verification of system properties, such as safety, is based on reachability
calculations, which are the sources of insurmountable complexity. This talk
addresses indirect verification methods, which are based on abstracting the
dynamical systems by models of reduced complexity and preserving central
properties of the original systems.


title: Networked Embedded Control Systems: from Modelling to Implementation

abstract:
  Networked Embedded Control Systems are distributed control systems where the
communication among plants, sensors, actuators and controllers occurs in a
shared network. They have been the subject of intensive study in the last few
years. In this paper we survey our contribution to this research topic.


title: An Integrated Framework for Diagnosis and Prognosis of Hybrid Systems

abstract:
  Complex systems are naturally hybrid: their dynamic behavior is both
continuous and discrete. For these systems, maintenance and repair are an
increasing part of the total cost of final product. Efficient diagnosis and
prognosis techniques have to be adopted to detect, isolate and anticipate
faults. This paper presents an original integrated theoretical framework for
diagnosis and prognosis of hybrid systems. The formalism used for hybrid
diagnosis is enriched in order to be able to follow the evolution of an aging
law for each fault of the system. The paper presents a methodology for
interleaving diagnosis and prognosis in a hybrid framework.


title: Completeness of Lyapunov Abstraction

abstract:
  In this work, we continue our study on discrete abstractions of dynamical
systems. To this end, we use a family of partitioning functions to generate an
abstraction. The intersection of sub-level sets of the partitioning functions
defines cells, which are regarded as discrete objects. The union of cells makes
up the state space of the dynamical systems. Our construction gives rise to a
combinatorial object - a timed automaton. We examine sound and complete
abstractions. An abstraction is said to be sound when the flow of the time
automata covers the flow lines of the dynamical systems. If the dynamics of the
dynamical system and the time automaton are equivalent, the abstraction is
complete.
  The commonly accepted paradigm for partitioning functions is that they ought
to be transversal to the studied vector field. We show that there is no
complete partitioning with transversal functions, even for particular dynamical
systems whose critical sets are isolated critical points. Therefore, we allow
the directional derivative along the vector field to be non-positive in this
work. This considerably complicates the abstraction technique. For
understanding dynamical systems, it is vital to study stable and unstable
manifolds and their intersections. These objects appear naturally in this work.
Indeed, we show that for an abstraction to be complete, the set of critical
points of an abstraction function shall contain either the stable or unstable
manifold of the dynamical system.


title: Approximated Symbolic Computations over Hybrid Automata

abstract:
  Hybrid automata are a natural framework for modeling and analyzing systems
which exhibit a mixed discrete continuous behaviour. However, the standard
operational semantics defined over such models implicitly assume perfect
knowledge of the real systems and infinite precision measurements. Such
assumptions are not only unrealistic, but often lead to the construction of
misleading models. For these reasons we believe that it is necessary to
introduce more flexible semantics able to manage with noise, partial
information, and finite precision instruments. In particular, in this paper we
integrate in a single framework based on approximated semantics different over
and under-approximation techniques for hybrid automata. Our framework allows to
both compare, mix, and generalize such techniques obtaining different
approximated reachability algorithms.


title:
World Automata: a compositional approach to model implicit communication
  in hierarchical Hybrid Systems

abstract:
  We propose an extension of Hybrid I/O Automata (HIOAs) to model agent systems
and their implicit communication through perturbation of the environment, like
localization of objects or radio signals diffusion and detection. The new
object, called World Automaton (WA), is built in such a way to preserve as much
as possible of the compositional properties of HIOAs and its underlying theory.
From the formal point of view we enrich classical HIOAs with a set of world
variables whose values are functions both of time and space. World variables
are treated similarly to local variables of HIOAs, except in parallel
composition, where the perturbations produced by world variables are summed. In
such way, we obtain a structure able to model both agents and environments,
thus inducing a hierarchy in the model and leading to the introduction of a new
operator. Indeed this operator, called inplacement, is needed to represent the
possibility of an object (WA) of living inside another object/environment (WA).


title: HyLTL: a temporal logic for model checking hybrid systems

abstract:
  The model-checking problem for hybrid systems is a well known challenge in
the scientific community. Most of the existing approaches and tools are limited
to safety properties only, or operates by transforming the hybrid system to be
verified into a discrete one, thus loosing information on the continuous
dynamics of the system. In this paper we present a logic for specifying complex
properties of hybrid systems called HyLTL, and we show how it is possible to
solve the model checking problem by translating the formula into an equivalent
hybrid automaton. In this way the problem is reduced to a reachability problem
on hybrid automata that can be solved by using existing tools.