title: Poisson cohomology and quantization

abstract:
  Let R be a commutative ring, and let A be a Poisson algebra over R. We
construct an (R,A)-Lie algebra structure, in the sense of Rinehart, on the
A-module of K\"ahler differentials of A depending naturally on A and the
Poisson bracket. This gives rise to suitable algebraic notions of Poisson
homology and cohomology for an arbitrary Poisson algebra. A geometric version
thereof includes the canonical homology and Poisson cohomology of a Poisson
manifold introduced by Brylinski, Koszul, and Lichnerowicz, and absorbes the
latter in standard homological algebra by expressing them as Tor and Ext
groups, respectively, over a suitable algebra of differential operators.
Furthermore, the Poisson structure determines a closed 2-form in the complex
computing Poisson cohomology. This 2-form generalizes the 2-form defining a
symplectic structure on a smooth manifold; moreover, the class of that 2-form
in Poisson cohomology generalizes the class in de Rham cohomology of a
symplectic structure on a smooth manifold and appears as a crucial ingredient
for the construction of suitable linear representations of A, viewed as a Lie
algebra; representations of this kind occur in quantum theory. To describe this
class and to construct the representations, we relate formal concepts of
connection and curvature generalizing the classical ones with extensions of Lie
algebras. We illustrate our results with a number of examples of Poisson
algebras and with a quantization procedure for a relativistic particle with
zero rest mass and spin zero.


title: Compressive Demodulation of Mutually Interfering Signals

abstract:
  Multi-User Detection is fundamental not only to cellular wireless
communication but also to Radio-Frequency Identification (RFID) technology that
supports supply chain management. The challenge of Multi-user Detection (MUD)
is that of demodulating mutually interfering signals, and the two biggest
impediments are the asynchronous character of random access and the lack of
channel state information. Given that at any time instant the number of active
users is typically small, the promise of Compressive Sensing (CS) is the
demodulation of sparse superpositions of signature waveforms from very few
measurements. This paper begins by unifying two front-end architectures
proposed for MUD by showing that both lead to the same discrete signal model.
Algorithms are presented for coherent and noncoherent detection that are based
on iterative matching pursuit. Noncoherent detection is all that is needed in
the application to RFID technology where it is only the identity of the active
users that is required. The coherent detector is also able to recover the
transmitted symbols. It is shown that compressive demodulation requires
$\mathcal{O}(K\log N(\tau+1))$ samples to recover $K$ active users whereas
standard MUD requires $N(\tau+1)$ samples to process $N$ total users with a
maximal delay $\tau$. Performance guarantees are derived for both coherent and
noncoherent detection that are identical in the way they scale with number of
active users. The power profile of the active users is shown to be less
important than the SNR of the weakest user. Gabor frames and Kerdock codes are
proposed as signature waveforms and numerical examples demonstrate the superior
performance of Kerdock codes - the same probability of error with less than
half the samples.


title: Chemistry of Impact-Generated Silicate Melt-Vapor Debris Disks

abstract:
  In the giant impact theory for lunar origin, the Moon forms from material
ejected by the impact into an Earth-orbiting disk. Here we report the initial
results from a silicate melt-vapor equilibrium chemistry model for such
impact-generated planetary debris disks. In order to simulate the chemical
behavior of a two-phase (melt+vapor) disk, we calculate the
temperature-dependent pressure and chemical composition of vapor in equilibrium
with molten silicate from 2000 to 4000 K. We consider the elements O, Na, K,
Fe, Si, Mg, Ca, Al, Ti, and Zn for a range of bulk silicate compositions
(Earth, Moon, Mars, eucrite parent body, angrites, and ureilites). In general,
the disk atmosphere is dominated by Na, Zn, and O2 at lower temperatures (<
3000 K) and SiO, O2, and O at higher temperatures. The high-temperature
chemistry is consistent for any silicate melt composition, and we thus expect
abundant SiO, O2, and O to be a common feature of hot, impact-generated debris
disks. In addition, the saturated silicate vapor is highly oxidizing, with
oxygen fugacity (fO2) values (and hence H2O/H2 and CO2/CO ratios) several
orders of magnitude higher than those in a solar-composition gas. High fO2
values in the disk atmosphere are found for any silicate composition because
oxygen is the most abundant element in rock. We thus expect high oxygen
fugacity to be a ubiquitous feature of any silicate melt-vapor disk produced
via collisions between rocky planets.


title: Toward real-time quantum imaging with a single pixel camera

abstract:
  We present a workbench for the study of real-time quantum imaging by
measuring the frame-by-frame quantum noise reduction of multi-spatial-mode twin
beams generated by four wave mixing in Rb vapor. Exploiting the multiple
spatial modes of this squeezed light source, we utilize spatial light
modulators to selectively pass macropixels of quantum correlated modes from
each of the twin beams to a high quantum efficiency balanced detector. In
low-light-level imaging applications, the ability to measure the quantum
correlations between individual spatial modes and macropixels of spatial modes
with a single pixel camera will facilitate compressive quantum imaging with
sensitivity below the photon shot noise limit.


title: Modular dynamical systems on networks

abstract:
  We propose a new framework for the study of continuous time dynamical systems
on networks. We view such dynamical systems as collections of interacting
control systems. We show that a class of maps between graphs called graph
fibrations give rise to maps between dynamical systems on networks. This allows
us to produce conjugacy between dynamical systems out of combinatorial data. In
particular we show that surjective graph fibrations lead to synchrony subspaces
in networks. The injective graph fibrations, on the other hand, give rise to
surjective maps from large dynamical systems to smaller ones. One can view
these surjections as a kind of "fast/slow" variable decompositions or as
"abstractions" in the computer science sense of the word.

categories: math.DS physics.soc-ph q-bio.MN q-bio.NC


title: Space Division Multiplexing in Optical Fibres

abstract:
  Optical communications technology has made enormous and steady progress for
several decades, providing the key resource in our increasingly
information-driven society and economy. Much of this progress has been in
finding innovative ways to increase the data carrying capacity of a single
optical fibre. In this search, researchers have explored (and close to
maximally exploited) every available degree of freedom, and even commercial
systems now utilize multiplexing in time, wavelength, polarization, and phase
to speed more information through the fibre infrastructure. Conspicuously, one
potentially enormous source of improvement has however been left untapped in
these systems: fibres can easily support hundreds of spatial modes, but today's
commercial systems (single-mode or multi-mode) make no attempt to use these as
parallel channels for independent signals.


title:
The Star Formation History of the very metal poor BCD IZw18 from HST/ACS
  data

abstract:
  We have derived the star formation history (SFH) of the blue compact dwarf
galaxy IZw18 through comparison of deep HST/ACS data with synthetic color
magnitude diagrams. A statistical analysis was implemented for the
identification of the best-fit SFH and relative uncertainties. We confirm that
IZw18 is not a truly young galaxy, having started forming stars earlier than ~1
Gyr ago, and possibly at epochs as old as a Hubble time. In IZw18's main body
we infer a lower limit of ~2 x 10^{6} M_sun for the mass locked-up in old
stars. IZw18' s main body has been forming stars very actively during the last
~10 Myr, with an average star formation rate (SFR) as high as ~1 M_sun/yr (or
~2 x 10^{-5} M_sun yr^{-1} pc^{-2}). On the other hand, the secondary body was
much less active at these epochs, in agreement with the absence of significant
nebular emission. The high current SFR can explain the very blue colors and the
high ionized gas content in IZw18, resembling primeval galaxies in the early
Universe. Detailed chemical evolution models are required to quantitatively
check whether the SFH from the synthetic CMDs can explain the low measured
element abundances, or if galactic winds with loss of metals are needed.


title:
PTFE treatment by remote atmospheric Ar/O2 plasmas: a simple reaction
  scheme model proposal

abstract:
  Polytetrafluoroethylene (PTFE) samples were treated by a remote atmospheric
pressure microwave plasma torch and analyzed by water contact angle (WCA) and
X-ray photoelectron spectroscopy (XPS). In the case of pure argon plasma a
decrease of WCA is observed meanwhile an increase of hydrophobicity was
observed when some oxygen was added to the discharge. The WCA results are
correlated to XPS of reference samples and the change of WCA are attributed to
changes in roughness of the samples. A simple kinetics scheme for the chemistry
on the PTFE surface is proposed to explain the results.


title: Spectral parameter power series for perturbed Bessel equations

abstract:
  A spectral parameter power series (SPPS) representation for regular solutions
of singular Bessel type Sturm-Liouville equations with complex coefficients is
obtained as well as an SPPS representation for the (entire) characteristic
function of the corresponding spectral problem on a finite interval. It is
proved that the set of zeros of the characteristic function coincides with the
set of all eigenvalues of the Sturm-Liouville problem. Based on the SPPS
representation a new mapping property of the transmutation operator for the
considered perturbed Bessel operator is obtained, and a new numerical method
for solving corresponding spectral problems is developed. The range of
applicability of the method includes complex coefficients, complex spectrum and
equations in which the spectral parameter stands at a first order linear
differential operator. On a set of known test problems we show that the
developed numerical method based on the SPPS representation is highly
competitive in comparison to the best available solvers such as SLEIGN2,
MATSLISE and some other codes and give an example of an exactly solvable test
problem admitting complex eigenvalues to which the mentioned solvers are not
applicable meanwhile the SPPS method delivers excellent numerical results.


title:
Yields of AGB and SAGB models with chemistry of low- and
  high-metallicity Globular Clusters

abstract:
  We present yields from stars of mass in the range Mo<M<8Mo of metallicities
Z=0.0003 and Z=0.008, thus encompassing the chemistry of low- and high-Z
Globular Clusters. The yields are based on full evolutionary computations,
following the evolution of the stars from the pre-Main Sequence through the
Asymptotic Giant Branch phase, until the external envelope is lost.
Independently of metallicity, stars with M<3Mo are dominated by Third
Dredge-Up, thus ejecting into their surroundings gas enriched in carbon and
nitrogen. Conversely, Hot Bottom Burning is the main responsible for the
modification of the surface chemistry of more massive stars, whose mass exceeds
3Mo: their gas shows traces of proton-capture nucleosynthesis. The extent of
Hot Bottom Burning turns out to be strongly dependent on metallicity. In this
paper we analyze the consequences of this fact. These results can be used to
understand the role played by intermediate mass stars in the self-enrichment
scenario of globular clusters: the results from spectroscopic investigations of
stars belonging to the second generation of clusters with different metallicity
will be used as an indirect test of the reliability of the present yields. The
treatment of mass loss and convection are confirmed as the main uncertainties
affecting the results obtained in the context of the modeling of the thermal
pulses phase. An indirect proof of this comes from the comparison with other
investigations in the literature, based on a different prescription for the
efficiency of convection in transporting energy and using a different recipe to
determine the mass loss rate.


title: Finite Decomposition Semigroups

abstract:
  In this paper, we explain the importance of finite decomposition semigroups
and present two theorems related to their structure.


title: Schatten classes and traces on compact groups

abstract:
  In this paper we present symbolic criteria for invariant operators on compact
topological groups $G$ characterising the Schatten-von Neumann classes
$S_{r}(L^{2}(G))$ for all $0<r\leq\infty$. Since it is known that for
pseudo-differential operators criteria in terms of kernels may be less
effective (Carleman's example), our criteria are given in terms of the
operators' symbols defined on the noncommutative analogue of the phase space
$G\times\hat{G}$, where $G$ is a compact topological (or Lie) group and
$\hat{G}$ is its unitary dual. We also show results concerning general
non-invariant operators as well as Schatten properties on Sobolev spaces. A
trace formula is derived for operators in the Schatten class $S_{1}(L^{2}(G))$.
Examples are given for Bessel potentials associated to sub-Laplacians (sums of
squares) on compact Lie groups, as well as for powers of the sub-Laplacian and
for other non-elliptic operators on SU(2)$\simeq\mathbb S^3$ and on SO(3).


title:
The IMACS Cluster Building Survey. I. Description of the Survey and
  Analysis Methods

abstract:
  The IMACS Cluster Building Survey uses the wide field spectroscopic
capabilities of the IMACS spectrograph on the 6.5m Baade Telescope to survey
the large-scale environment surrounding rich intermediate-redshift clusters of
galaxies. The goal is to understand the processes which may be transforming
star-forming field galaxies into quiescent cluster members as groups and
individual galaxies fall into the cluster from the surrounding supercluster.
This first paper describes the survey: the data taking and reduction methods.
We provide new calibrations of star formation rates derived from optical and
infrared spectroscopy and photometry. We demonstrate that there is a tight
relation between the observed star formation rate per unit B luminosity, and
the ratio of the extinctions of the stellar continuum and the optical emission
lines. With this, we can obtain accurate extinction-corrected colors of
galaxies. Using these colors as well as other spectral measures, we determine
new criteria for the existence of ongoing and recent starbursts in galaxies.


title:
The IMACS Cluster Building Survey. III. The Star Formation Histories of
  Field Galaxies

abstract:
  Using data from the IMACS Cluster Building Survey and from nearby galaxy
surveys, we examine the evolution of the rate of star formation in field
galaxies from $ z = 0.60$ to the present. Fitting the luminosity function to a
standard Schechter form, we find a rapid evolution of $M_B^*$ consistent with
that found in other deep surveys; at the present epoch $M_B^*$ is evolving at
the rate of $0.38 Gyr^{-1}$, several times faster than the predictions of
simple models for the evolution of old, coeval galaxies. The evolution of the
distribution of specific star formation rates (SSFR) is also too rapid to
explain by such models. We demonstrate that starbursts cannot, even in
principle, explain the evolution of the SSFR distribution. However, the rapid
evolution of both $M_B^*$ and the SSFR distribution can be explained if some
fraction of galaxies have star formation rates characterized by both short rise
and fall times and by an epoch of peak star formation more recent than the
majority of galaxies. Although galaxies of every stellar mass up to
$1.4\times10^{11}\Msun$ show a range of epochs of peak star formation, the
fraction of "younger" galaxies falls from about 40% at a mass of
$4\times10^{10}\Msun$ to zero at a mass of $1.4\times10^{11}\Msun$. The
incidence of younger galaxies appears to be insensitive to the density of the
local environment; but does depend on group membership: relatively isolated
galaxies are much more likely to be young than are group members.


title:
The IMACS Cluster Building Survey: IV. The Log-normal Star Formation
  History of Galaxies

abstract:
  We present here a simple model for the star formation history of galaxies
that is successful in describing both the star formation rate density over
cosmic time, as well as the distribution of specific star formation rates of
galaxies at the current epoch, and the evolution of this quantity in galaxy
populations to a redshift of z=1. We show first that the cosmic star formation
rate density is remarkably well described by a simple log-normal in time. We
next postulate that this functional form for the ensemble is also a reasonable
description for the star formation histories of individual galaxies. Using the
measured specific star formation rates for galaxies at z~0 from Paper III in
this series, we then construct a realisation of a universe populated by such
galaxies in which the parameters of the log-normal star formation history of
each galaxy are adjusted to match the specific star formation rates at z~0 as
well as fitting, in ensemble, the cosmic star formation rate density from z=0
to z=8. This model predicts, with striking fidelity, the distribution of
specific star formation rates in mass-limited galaxy samples to z=1; this match
is not achieved by other models with a different functional form for the star
formation histories of individual galaxies, but with the same number of degrees
of freedom, suggesting that the log-normal form is well matched to the likely
actual histories of individual galaxies. We also impose the specific star
formation rate versus mass distributions at higher redshifts from Paper III as
constraints on the model, and show that, as previously suggested, some galaxies
in the field, particularly low mass galaxies, are quite young at intermediate
redshifts. As emphasized in Paper III, starbursts are insufficient
...[abridged]


title:
Hill's Equation with Small Fluctuations: Cycle to Cycle Variations and
  Stochastic Processes

abstract:
  Hill's equations arise in a wide variety of physical problems, and are
specified by a natural frequency, a periodic forcing function, and a forcing
strength parameter. This classic problem is generalized here in two ways: [A]
to Random Hill's equations which allow the forcing strength q_k, the
oscillation frequency \lambda_k, and the period \tau_k of the forcing function
to vary from cycle to cycle, and [B] to Stochastic Hill's equations which
contain (at least) one additional term that is a stochastic process \xi. This
paper considers both random and stochastic Hill's equations with small
parameter variations, so that p_k=q_k-<q_k>, \ell_k=\lambda_k-<\lambda_k>, and
\xi are all O(\epsilon), where \epsilon<<1. We show that random Hill's
equations and stochastic Hill's equations have the same growth rates when the
parameter variations p_k and \ell_k obey certain constraints given in terms of
the moments of \xi. For random Hill's equations, the growth rates for the
solutions are given by the growth rates of a matrix transformation, under
matrix multiplication, where the matrix elements vary from cycle to cycle.
Unlike classic Hill's equations where the parameter space (the \lambda-q plane)
displays bands of stable solutions interlaced with bands of unstable solutions,
random Hill's equations are generically unstable. We find analytic
approximations for the growth rates of the instability; for the regime where
Hill's equation is classically stable, and the parameter variations are small,
the growth rate \gamma = O(\epsilon^2). Using the relationship between the
(\ell_k,p_k) and the \xi, this result for \gamma can be used to find growth
rates for stochastic Hill's equations.


title: Base manifolds for Lagrangian fibrations on hyperk\"ahler manifolds

abstract:
  We show that the base manifold of a Lagrangian fibration on a hyperk\"ahler
manifold is isomorphic to complex projective space. This generalises a theorem
of J.-M. Hwang to the K\"ahler case.


title:
Can Life History Predict the Effect of Demographic Stochasticity on
  Extinction Risk?

abstract:
  Demographic stochasticity is important in determining extinction risks of
small populations, but it is largely unknown how its effect depends on the life
histories of species. We modeled effects of demographic stochasticity on
extinction risk in a broad range of generalized life histories, using matrix
models and branching processes. Extinction risks of life histories varied
greatly in their sensitivity to demographic stochasticity. Comparing life
histories, extinction risk generally increased with increasing fecundity and
decreased with higher ages of maturation. Effects of adult survival depended on
age of maturation. At lower ages of maturation, extinction risk peaked at
intermediate levels of adult survival, but it increased along with adult
survival at higher ages of maturation. These differences were largely explained
by differences in sensitivities of population growth to perturbations of
life-history traits. Juvenile survival rate contributed most to total
demographic variance in the majority of life histories. Our general results
confirmed earlier findings, suggesting that empirical patterns can be explained
by a relatively simple model. Thus, basic life history information can be used
to assign life-history-specific sensitivity to demographic stochasticity. This
is of great value when assessing the vulnerability of small populations.


title: On the Locality of Codeword Symbols in Non-Linear Codes

abstract:
  Consider a possibly non-linear (n,K,d)_q code. Coordinate i has locality r if
its value is determined by some r other coordinates. A recent line of work
obtained an optimal trade-off between information locality of codes and their
redundancy. Further, for linear codes meeting this trade-off, structure
theorems were derived. In this work we give a new proof of the locality /
redundancy trade-off and generalize structure theorems to non-linear codes.


title: Generation cuts and Born suppression in POWHEG

abstract:
  In this short note we discuss the origin of spikes in physical distributions
in dijet production, originating after the Monte Carlo shower of POWHEG Les
Houches events. We introduce a refinement of the way in which the POWHEG BOX
separates the singular regions that reduces the appearance of spikes in the
computed distributions. We also study the sensitivity of the results due to a
modification of the way the POWHEG events are passed to the shower Monte Carlo
program. We recommend that the new features should be used always in dijet
production.


title: The validity of perturbation theory for the O(N) nonlinear sigma models

abstract:
  Recently it has been claimed that ordinary perturbation theory (OPT) gives
incorrect weak coupling expansions for lattice O(N) non-linear sigma models in
the infinite volume limit, and in particular that the two-dimensional
non-abelian models are not asymptotically free, contrary to previous findings.
Here it is argued that the problem occurs only for one-dimensional infinite
lattices, and that in general, OPT gives correct expansions if physical
quantities are first computed on a finite lattice, and the infinite volume
limit is taken at the end. In one dimension the expansion is sensitive to
boundary conditions because of the severe infrared behavior, but this is not
expected to happen in higher dimensions. It is concluded that spin
configurations which are far from the perturbative vacuum have too small a
measure in the path integral to invalidate OPT, even though they are
energetically allowed for non-zero values of the coupling.


title: Semicorings and Semicomodules

abstract:
  In this paper, we introduce and investigate \emph{semicorings} over
associative semirings and their categories of \emph{semicomodules.} Our results
generalize old and recent results on corings over rings and their categories of
comodules. The generalization is \emph{not} straightforward and even subtle at
some places due to the nature of the base category of commutative monoids which
is neither Abelian (not even additive) nor homological, and has no non-zero
injective objects. To overcome these and other difficulties, a combination of
methods and techniques from categorical, homological and universal algebra is
used including a new notion of exact sequences of semimodules over semirings.


title: Quantum Cosmological Perturbations: Predictions and Observations

abstract:
  I consider the generic model independent predictions of the theory of quantum
cosmological perturbations. To describe the stage of cosmic inflation, where
these perturbations are amplified, the hydrodynamical approch is used. The
inflationary stage is completely characterized by the deviation of the equation
of state from cosmological constant which is a smooth function of the number of
e-folds until the end of inflation. It is shown that in this case the spectral
index should deviate from the flat one at least by 3 percent irrespective of
any particular scenario. Given the value of the spectral index the lower bound
on the amount of the gravitational waves produced is derived. Finally the
relation between effective hydrodynamical description of inflation and
inflationary scenarios is discussed.


title: Strong coupling theory of heavy fermion criticality

abstract:
  We present a theory of the scaling behavior of the thermodynamic, transport
and dynamical properties of a three-dimensional metal at an antiferromagnetic
critical point. We show how the critical spin fluctuations at the AFM
wavevector q=Q induce energy fluctuations at small q, giving rise to a
diverging quasiparticle effective mass over the whole Fermi surface. The
coupling of the fermionic and bosonic degrees of freedom leads to a
self-consistent relation for the effective mass, which has a strong coupling
solution in addition to the well-known weak-coupling, spin-density-wave
solution. We thereby use the recently-introduced concept of critical
quasiparticles, employing a scale-dependent effective mass ratio m*/m and
quasiparticle weight factor Z. As a consequence of the diverging effective mass
the Landau Fermi liquid interaction is found to diverge in all channels except
the critical one, causing important vertex corrections. The ensuing spin
fluctuation spectrum obeys omega/T scaling. Our results are in good agreement
with experimental data on the heavy fermion compounds YbRh2Si2$ and
CeCu(6-x)Au(x) assuming 3D and 2D spin fluctuations, respectively.


title: Computing shortest paths in 2D and 3D memristive networks

abstract:
  Global optimisation problems in networks often require shortest path length
computations to determine the most efficient route. The simplest and most
common problem with a shortest path solution is perhaps that of a traditional
labyrinth or maze with a single entrance and exit. Many techniques and
algorithms have been derived to solve mazes, which often tend to be
computationally demanding, especially as the size of maze and number of paths
increase. In addition, they are not suitable for performing multiple shortest
path computations in mazes with multiple entrance and exit points. Mazes have
been proposed to be solved using memristive networks and in this paper we
extend the idea to show how networks of memristive elements can be utilised to
solve multiple shortest paths in a single network. We also show simulations
using memristive circuit elements that demonstrate shortest path computations
in both 2D and 3D networks, which could have potential applications in various
fields.


title: Ferroelectric instability of two-dimensional crystals

abstract:
  The macroscopic dielectric permittivity of dielectric crystals is related to
the microscopic atomic polarizability of constituent atoms by the known
Clausius-Mossotti relation obtained in the middle of 19th century. We derive a
similar relation for recently discovered two-dimensional crystals (mono- and
bilayer graphene, boron nitride, etc) and show that, in contrast to
three-dimensional materials, much stronger electron-electron interaction in two
dimensions leads to a spontaneous electric polarization of the ground state of
two-dimensional crystals. The predicted ferroelectric transition may have
interesting applications in electrodynamics and optics.


title:
A Population of Relic Intermediate-Mass Black Holes in the Halo of the
  Milky Way

abstract:
  If "seed" central black holes were common in the subgalactic building blocks
that merged to form present-day massive galaxies, then relic intermediate-mass
black holes (IMBHs) should be present in the Galactic bulge and halo. We use a
particle tagging technique to dynamically populate the N-body Via Lactea II
high-resolution simulation with black holes, and assess the size, properties,
and detectability of the leftover population. The method assigns a black hole
to the most tightly bound central particle of each subhalo at infall according
to an extrapolation of the M_BH-sigma_* relation, and self-consistently follows
the accretion and disruption of Milky Way progenitor dwarfs and their holes in
a cosmological "live" host from high redshift to today. We show that, depending
on the minimum stellar velocity dispersion, sigma_m, below which central black
holes are assumed to be increasingly rare, as many as ~2000 (sigma_m=3 km/s) or
as few as ~70 (sigma_m=12 km/s) IMBHs may be left wandering in the halo of the
Milky Way today. The fraction of IMBHs kicked out of their host by
gravitational recoil is < 20%. We identify two main Galactic subpopulations,
"naked" IMBHs, whose host subhalos were totally destroyed after infall, and
"clothed" IMBHs residing in dark matter satellites that survived tidal
stripping. Naked IMBHs typically constitute 40-50% of the total and are more
centrally concentrated. We show that, in the sigma_m=12 km/s scenario, the
clusters of tightly bound stars that should accompany naked IMBHs would be
fainter than m_V=16 mag, spatially resolvable, and have proper motions of
0.1-10 milliarcsec per year. Their detection may provide an observational tool
to constrain the formation history of massive black holes in the early
Universe.


title:
VIPERS: An Unprecedented View of Galaxies and Large-Scale Structure
  Halfway Back in the Life of the Universe

abstract:
  The VIMOS Public Extragalactic Redshift Survey (VIPERS) is an ongoing ESO
Large Programme to map in detail the large-scale distribution of galaxies at
0.5 < z <1.2. With a combination of volume and sampling density that is unique
for these redshifts, it focuses on measuring galaxy clustering and related
cosmological quantities as part of the grand challenge of understanding the
origin of cosmic acceleration. VIPERS has also been designed to guarantee a
broader legacy, allowing detailed investigations of the properties and
evolutionary trends of z~1 galaxies. The survey strategy exploits the specific
advantages of the VIMOS spectrograph at the VLT, aiming at a final sample of
nearly 100,000 galaxy redshifts to iAB = 22.5 mag, which represents the largest
redshift survey ever performed with ESO telescopes. In this introductory
article we describe the survey construction, together with early results based
on a first sample of ~55,000 galaxies.


title: Potential Maximal Clique Algorithms for Perfect Phylogeny Problems

abstract:
  Kloks, Kratsch, and Spinrad showed how treewidth and minimum-fill, NP-hard
combinatorial optimization problems related to minimal triangulations, are
broken into subproblems by block subgraphs defined by minimal separators. These
ideas were expanded on by Bouchitt\'e and Todinca, who used potential maximal
cliques to solve these problems using a dynamic programming approach in time
polynomial in the number of minimal separators of a graph. It is known that
solutions to the perfect phylogeny problem, maximum compatibility problem, and
unique perfect phylogeny problem are characterized by minimal triangulations of
the partition intersection graph. In this paper, we show that techniques
similar to those proposed by Bouchitt\'e and Todinca can be used to solve the
perfect phylogeny problem with missing data, the two- state maximum
compatibility problem with missing data, and the unique perfect phylogeny
problem with missing data in time polynomial in the number of minimal
separators of the partition intersection graph.


title:
Magnetoelectric effects and valley controlled spin quantum gates in
  transition metal dichalcogenide bilayers

abstract:
  In monolayer group-VI transition metal dichalcogenides (TMDC), charge
carriers have spin and valley degrees of freedom, both associated with magnetic
moments. On the other hand, the layer degree of freedom in multilayers is
associated with electrical polarization. Here, we show that TMDC bilayers offer
an unprecedented platform to realize a strong coupling between the spin, layer
pseudospin, and valley degrees of freedom of holes. Such coupling not only
gives rise to the spin Hall effect and spin circular dichroism in inversion
symmetric bilayer, but also leads to a variety of magnetoelectric effects
permitting quantum manipulation of these electronic degrees of freedom.
Oscillating electric and magnetic fields can both drive the hole spin resonance
where the two fields have valley-dependent interference, making possible a
prototype interplay between the spin and valley as information carriers for
potential valley-spintronic applications. We show how to realize quantum gates
on the spin qubit controlled by the valley bit.


title: A variant of nonsmooth maximum principle for state constrained problems

abstract:
  We derive a variant of the nonsmooth maximum principle for problems with pure
state constraints. The interest of our result resides on the nonsmoothness
itself since, when applied to smooth problems, it coincides with known results.
Remarkably, in the normal form, our result has the special feature of being a
sufficient optimality condition for linearconvex problems, a feature that the
classical Pontryagin maximum principle had whereas the nonsmooth version had
not. This work is distinct to previous work in the literature since, for state
constrained problems, we add the Weierstrass conditions to adjoint inclusions
using the joint subdifferentials with respect to the state and the control. Our
proofs use old techniques developed in [16], while appealing to new results in
[7].


title: A Quorum Sensing Inspired Algorithm for Dynamic Clustering

abstract:
  Quorum sensing is a decentralized biological process, through which a
community of cells with no global awareness coordinate their functional
behaviors based solely on cell-medium interactions and local decisions. This
paper draws inspirations from quorum sensing and colony competition to derive a
new algorithm for data clustering. The algorithm treats each data as a single
cell, and uses knowledge of local connectivity to cluster cells into multiple
colonies simultaneously. It simulates auto-inducers secretion in quorum sensing
to tune the influence radius for each cell. At the same time, sparsely
distributed core cells spread their influences to form colonies, and
interactions between colonies eventually determine each cell's identity. The
algorithm has the flexibility to analyze not only static but also time-varying
data, which surpasses the capacity of many existing algorithms. Its stability
and convergence properties are established. The algorithm is tested on several
applications, including both synthetic and real benchmarks data sets, alleles
clustering, community detection, image segmentation. In particular, the
algorithm's distinctive capability to deal with time-varying data allows us to
experiment it on novel applications such as robotic swarms grouping and
switching model identification. We believe that the algorithm's promising
performance would stimulate many more exciting applications.


title: Quantum mechanics from invariance principles

abstract:
  Quantum mechanics is an extremely successful theory of nature and yet it
lacks an intuitive axiomatization. In contrast, the special theory of
relativity is well understood and is rooted into natural or experimentally
justified postulates. Here we introduce an axiomatization approach to quantum
mechanics which is very similar to special theory of relativity derivation. The
core idea is that a composed system obeys the same laws of nature as its
components. This leads to a Jordan-Lie algebraic formulation of quantum
mechanics. The starting assumptions are minimal: the laws of nature are
invariant under time evolution, the laws of nature are invariant under tensor
composition, the laws of nature are relational, together with the ability to
define a physical state (positivity). Quantum mechanics is singled out by a
fifth experimentally justified postulate: nature violates Bell inequalities.


title:
Ideas of Four-Fermion Operators in Electromagnetic Form Factor
  Calculations

abstract:
  Four-fermion operators have been utilized in the past to link the
quark-exchange processes in the interaction of hadrons with the effective
meson-exchange amplitudes. In this paper, we apply the similar idea of a Fierz
rearrangement to the electromagnetic processes and focus on the electromagnetic
form factors of the nucleon and the electron. We explain the motivation of
using four-fermion operators and discuss the advantage of this method in
computing electromagnetic processes.


title: Krull dimension and Monomial Orders

abstract:
  We introduce the notion of independent sequences with respect to a monomial
order by using the least terms of polynomials vanishing at the sequence. Our
main result shows that the Krull dimension of a Noetherian ring is equal to the
supremum of the length of independent sequences. The proof has led to other
notions of independent sequences, which have interesting applications. For
example, we can characterize the maximum number of analytically independent
elements in an arbitrary ideal of a local ring and that dim B is not greater
than dim A if B is a subalgebra of A and A is a (not necessarily finitely
generated) subalgebra of a finitely generated algebra over a Noetherian
Jacobson ring.


title: Fast selection of N-2 contingencies for online security assessment

abstract:
  We propose a novel algorithm for selection of dangerous N-2 contingencies
associated with line or generator failures. The algorithm is based on iterative
filtering of the set of all possible double contingencies. It is certified to
identify all the dangerous contingencies, and has the complexity comparable to
the N-1 contingency screening. Tests performed on realistic model of Polish
power grid with about 3000 buses show that only two iterations of algorithm
allow one to certify the safety of 99.9% of all double contingencies, leaving
only 0.1% of the most dangerous ones for direct analysis.


title:
Non local Lotka-Volterra system with cross-diffusion in an heterogeneous
  medium

abstract:
  We introduce a stochastic individual model for the spatial behavior of an
animal population of dispersive and competitive species, considering various
kinds of biological effects, such as heterogeneity of environmental conditions,
mutual attractive or repulsive interactions between individuals or competition
between them for resources. As a consequence of the study of the large
population limit, global existence of a nonnegative weak solution to a
multidimensional parabolic strongly coupled model of competing species is
proved. The main new feature of the corresponding integro-differential equation
is the nonlocal nonlinearity appearing in the diffusion terms, which may depend
on the spatial densities of all population types. Moreover, the diffusion
matrix is generally not strictly positive definite and the cross-diffusion
effect allows for linearly growing influences of the subpopulations' sizes. We
prove uniqueness of the finite measure-valued solution and give conditions
under which the solution takes values in a functional space. We then make the
competition kernels converge to a Dirac measure and obtain the existence of a
solution to a locally competitive version of the previous equation. The large
population limit is obtained by means of weak convergence tools for measure
valued processes. The techniques employed in the study of the liming equation
are novel, and are essentially based on the underlying stochastic flow related
to the dispersive part of the dynamics, together with the use of suitable dual
distances in the space of finite measures. This is an extended version of the
paper "Non local Lotka-Volterra system with cross-diffusion in a heterogeneous
medium" appeared in J. Math. Biol (2015) 70:829-854.


title: Two-dimensional Einstein manifolds in geometrothermodynamics

abstract:
  We present a class of thermodynamic systems with constant thermodynamic
curvature which, within the context of geometric approaches of thermodynamics,
can be interpreted as constant thermodynamic interaction among their
components. In particular, for systems constrained by the vanishing of the
Hessian curvature we write down the systems of partial differential equations.
In such a case it is possible to find a subset of solutions lying on a
circumference in an abstract space constructed from the first derivatives of
the isothermal coordinates. We conjecture that solutions on the characteristic
circumference are of physical relevance, separating them from those of pure
mathematical interest. We present the case of a one-parameter family of
fundamental relations that -- when lying in the circumference -- describe a
polytropic fluid.


title:
The Gel'fand-Levitan-Krein method and the globally convergent method for
  experimental data

abstract:
  Comparison of numerical performances of two methods for coefficient inverse
problems is described. The first one is the classical Gel'fand-Levitan-Krein
equation method, and the second one is the recently developed approximately
globally convergent numerical method. This comparison is performed for both
computationally simulated and experimental data.


title:
Reducing the numerical effort of finite-temperature density matrix
  renormalization group transport calculations

abstract:
  Finite-temperature transport properties of one-dimensional systems can be
studied using the time dependent density matrix renormalization group via the
introduction of auxiliary degrees of freedom which purify the thermal
statistical operator. We demonstrate how the numerical effort of such
calculations is reduced when the physical time evolution is augmented by an
additional time evolution within the auxiliary Hilbert space. Specifically, we
explore a variety of integrable and non-integrable, gapless and gapped models
at temperatures ranging from T=infty down to T/bandwidth=0.05 and study both
(i) linear response where (heat and charge) transport coefficients are
determined by the current-current correlation function and (ii) non-equilibrium
driven by arbitrary large temperature gradients. The modified DMRG algorithm
removes an 'artificial' build-up of entanglement between the auxiliary and
physical degrees of freedom. Thus, longer time scales can be reached.


title: On Finite Alphabet Compressive Sensing

abstract:
  This paper considers the problem of compressive sensing over a finite
alphabet, where the finite alphabet may be inherent to the nature of the data
or a result of quantization. There are multiple examples of finite alphabet
based static as well as time-series data with inherent sparse structure; and
quantizing real values is an essential step while handling real data in
practice. We show that there are significant benefits to analyzing the problem
while incorporating its finite alphabet nature, versus ignoring it and
employing a conventional real alphabet based toolbox. Specifically, when the
alphabet is finite, our techniques (a) have a lower sample complexity compared
to real-valued compressive sensing for sparsity levels below a threshold; (b)
facilitate constructive designs of sensing matrices based on coding-theoretic
techniques; (c) enable one to solve the exact $\ell_0$-minimization problem in
polynomial time rather than a approach of convex relaxation followed by
sufficient conditions for when the relaxation matches the original problem; and
finally, (d) allow for smaller amount of data storage (in bits).


title: Fluid elasticity increases the locomotion of flexible swimmers

abstract:
  We conduct experiments with flexible swimmers to address the impact of fluid
viscoelasticity on their locomotion. The swimmers are composed of a magnetic
head actuated in rotation by a frequency-controlled magnetic field and a
flexible tail whose deformation leads to forward propulsion. We consider both
viscous Newtonian and glucose-based Boger fluids with similar viscosities. We
find that the elasticity of the fluid systematically enhances the locomotion
speed of the swimmer, and that this enhancement increases with Deborah number.
Using Particle Image Velocimetry to visualize the flow field, we find a
significant difference in the amount of shear between the rear and leading
parts of the swimmer head. We conjecture that viscoelastic normal stresses lead
to a net elastic forces in the swimming direction and thus a faster swimming
speed.


title: Computing convolution on grammar-compressed text

abstract:
  The convolution between a text string $S$ of length $N$ and a pattern string
$P$ of length $m$ can be computed in $O(N \log m)$ time by FFT. It is known
that various types of approximate string matching problems are reducible to
convolution. In this paper, we assume that the input text string is given in a
compressed form, as a \emph{straight-line program (SLP)}, which is a context
free grammar in the Chomsky normal form that derives a single string. Given an
SLP $\mathcal{S}$ of size $n$ describing a text $S$ of length $N$, and an
uncompressed pattern $P$ of length $m$, we present a simple $O(nm \log m)$-time
algorithm to compute the convolution between $S$ and $P$. We then show that
this can be improved to $O(\min\{nm, N-\alpha\} \log m)$ time, where $\alpha
\geq 0$ is a value that represents the amount of redundancy that the SLP
captures with respect to the length-$m$ substrings. The key of the improvement
is our new algorithm that computes the convolution between a trie of size $r$
and a pattern string $P$ of length $m$ in $O(r \log m)$ time.


title:
Diffusion Thermopower of Quantum Hall States Measured in Corbino
  Geometry

abstract:
  We have measured the diffusion thermopower of a quantum Hall system in a
Corbino setup. A concentric electron-temperature gradient is introduced by
irradiating microwaves, via a coplanar waveguide, near the outer rim of a
circular mesa of a two-dimensional electron gas. The resulting radial
thermovoltages exhibit sawtooth-like oscillations with the magnetic field,
taking large positive (negative) values just below (above) integer fillings
with sign reversal at the center of the quantum Hall plateaus. The behavior is
in agreement with a recent theory [Y. Barlas and K. Yang: Phys. Rev. B 85
(2012) 195107], which treats disorder within the self-consistent Born
approximation.


title:
Dispersive spin excitations in highly overdoped cuprates revealed by
  resonant inelastic x-ray scattering

abstract:
  Using resonant inelastic x-ray scattering (RIXS) at the Cu $L$-absorption
edge, we have observed intense, dispersive spin excitations in highly overdoped
Tl$_2$Ba$_2$CuO$_{6+\delta}$ (superconducting $T_c =6$ K), a compound whose
normal-state charge transport and thermodynamic properties have been studied
extensively and shown to exhibit canonical Fermi-liquid behavior. Complementary
RIXS experiments on slightly overdoped Tl$_2$Ba$_2$CuO$_{6+\delta}$ ($T_c =89$
K) and on Y$_{1-x}$Ca$_{x}$Ba$_2$Cu$_3$O$_{6+\delta}$ compounds spanning a wide
range of doping levels indicate that these excitations exhibit energies and
energy-integrated spectral weights closely similar to those of
antiferromagnetic magnons in undoped cuprates. The surprising coexistence of
Fermi-liquid-like charge excitations and high-energy spin excitations
reminiscent of antiferromagnetic insulators in highly overdoped compounds poses
a challenge to current theoretical models of the cuprates.


title: An Adaptive Methodology for Ubiquitous ASR System

abstract:
  Achieving and maintaining the performance of ubiquitous (Automatic Speech
Recognition) ASR system is a real challenge. The main objective of this work is
to develop a method that will improve and show the consistency in performance
of ubiquitous ASR system for real world noisy environment. An adaptive
methodology has been developed to achieve an objective with the help of
implementing followings, -Cleaning speech signal as much as possible while
preserving originality / intangibility using various modified filters and
enhancement techniques. -Extracting features from speech signals using various
sizes of parameter. -Train the system for ubiquitous environment using
multi-environmental adaptation training methods. -Optimize the word recognition
rate with appropriate variable size of parameters using fuzzy technique. The
consistency in performance is tested using standard noise databases as well as
in real world environment. A good improvement is noticed. This work will be
helpful to give discriminative training of ubiquitous ASR system for better
Human Computer Interaction (HCI) using Speech User Interface (SUI).


title: Stabilizers of Ergodic Actions of Lattices and Commensurators

abstract:
  We prove that any ergodic measure-preserving action of an irreducible lattice
in a semisimple group, with finite center and each simple factor having rank at
least two, either has finite orbits or has finite stabilizers. The same
dichotomy holds for many commensurators of such lattices.
  The above are derived from more general results on groups with the Howe-Moore
property and property $(T)$. We prove similar results for commensurators in
such groups and for irreducible lattices (and commensurators) in products of at
least two such groups, at least one of which is totally disconnected.


title:
Self-organized Archimedean Spiral Pattern: Regular Bundling of Fullerene
  through Solvent Evaporation

abstract:
  We report the spontaneous generation of an Archimedean spiral pattern of
fullerene via the evaporation of solvent. The self-organized spiral pattern
exhibited equi-spacing on the order of micrometer between neighboring stripes.
The characteristics of the spirals, such as the spacing between stripes, the
number of stripes and the band width of stripes, could be controlled by tuning
the thickness of the liquid bridge and the concentration of solution. The
mechanism of pattern formation is interpreted in terms of a specific traveling
wave on the liquid-solid interface accompanied by a stick-slip process of the
contact line.


title:
The influence of residual oxidizing impurities on the synthesis of
  graphene by atmospheric pressure chemical vapor deposition

abstract:
  The growth of graphene on copper by atmospheric pressure chemical vapor
deposition in a system free of pumping equipment is investigated. The emphasis
is put on the necessity of hydrogen presence during graphene synthesis and
cooling. In the absence of hydrogen during the growth step or cooling at slow
rate, weak carbon coverage, consisting mostly of oxidized and amorphous carbon,
is obtained on the copper catalyst. The oxidation originates from the
inevitable occurrence of residual oxidizing impurities in the reactor's
atmosphere. Graphene with appreciable coverage can be grown within the
vacuum-free furnace only upon admitting hydrogen during the growth step. After
formation, it is preserved from the destructive effect of residual oxidizing
contaminants once exposure at high temperature is minimized by fast cooling or
hydrogen flow. Under these conditions, micrometer-sized hexagon-shaped graphene
domains of high structural quality are achieved.


title:
On the Polarization of non-Guassian optical quantum field: higher-order
  optical-polarization

abstract:
  Polarization of light signifies transversal, anisotropic and asymmetrical
statistical property of electromagnetic radiation about direction of
propagation. Traditionally, optical-polarization is characterized by Stokes
theory susceptible to be insufficient in assessing polarization structure of
optical quantum fields and, also, does not decipher twin characteristic
polarization parameters (ratio of real amplitudes and difference in phases). An
alternative way, in spirit of classical description of optical-polarization, is
introduced which can be generalized to deal higher-order polarization of
quantum light, particularly, prepared in non-Guassian Schrodinger Cat or
Cat-like states and entangled bi-modal coherent states. On account of pseudo
mono-modal or multi-modal nature of such optical quantum field, higher-order
polarization is seen to be highly sensitive to the basis of description.


title:
Search for $\nu_\mu \rightarrow \nu_e$ oscillations with the OPERA
  experiment in the CNGS beam

abstract:
  A first result of the search for \numu $\rightarrow$ \nue oscillations in the
OPERA experiment, located at the Gran Sasso Underground Laboratory, is
presented. The experiment looked for the appearance of \nue in the CNGS
neutrino beam using the data collected in 2008 and 2009. Data are compatible
with the non-oscillation hypothesis in the three-flavour mixing model. A
further analysis of the same data constrains the non-standard oscillation
parameters $\theta_{new}$ and $\Delta m^2_{new}$ suggested by the LSND and
MiniBooNE experiments. For large $\Delta m^{2}_{new}$ values ($>$0.1 eV$^{2}$),
the OPERA 90% C.L. upper limit on sin$^{2}(2\theta_{new})$ based on a Bayesian
statistical method reaches the value $7.2 \times 10^{-3}$.


title: Overview of Optical Interconnect Technology

abstract:
  Optical interconnect is seen as a potential solution to meet the performance
requirements of current and future generation of data processors. Optical
interconnects have negligible frequency dependent loss, low cross talk and high
band width. Optical interconnects are not much used commercially since optical
interconnects technology is incompatible with manufacturing processes and
assembly methods that are currently used in the semiconductor industry. There
are many promising optical interconnect technologies and this paper presents a
brief analysis of current state of optical interconnect technology.


title: On Algebraic Semigroups and Monoids, II

abstract:
  Consider an algebraic semigroup $S$ and its closed subscheme of idempotents,
$E(S)$. When $S$ is commutative, we show that $E(S)$ is finite and reduced; if
in addition $S$ is irreducible, then $E(S)$ is contained in a smallest closed
irreducible subsemigroup of $S$, and this subsemigroup is an affine toric
variety. It follows that $E(S)$ (viewed as a partially ordered set) is the set
of faces of a rational polyhedral convex cone. On the other hand, when $S$ is
an irreducible algebraic monoid, we show that $E(S)$ is smooth, and its
connected components are conjugacy classes of the unit group.


title: A liability tracking approach to long term management of pension funds

abstract:
  We propose a long term portfolio management method which takes into account a
liability. Our approach is based on the LQG (Linear, Quadratic cost, Gaussian)
control problem framework and then the optimal portfolio strategy hedges the
liability by directly tracking a benchmark process which represents the
liability. Two numerical results using empirical data published by Japanese
organizations are served: simulations tracking an artificial liability and an
estimated liability of Japanese organization. The latter one demonstrates that
our optimal portfolio strategy can hedge his or her liability.


title:
Optimal laser pulse design for transferring the coherent nuclear wave
  packet of H$_2^+$

abstract:
  Within the Franck-Condon approximation, the single ionization of H$_2$ leaves
H$_2^+$ in a coherent superposition of 19 nuclear vibrational states. We
numerically design an optimal laser pulse train to transfer such a coherent
nuclear wave packet to the ground vibrational state of H$_2^+$. The simulation
results show that the population of the ground state after the transfer is more
than 91%. Frequency analysis of the designed optimal pulse reveals that the
transfer principle is mainly an anti-Stokes transition, i.e., the H$_2^+$ in
$1s\sigma_g$ with excited nuclear vibrational states is first pumped to
$2p\sigma_g$ state by the pulse at an appropriate time, and then dumped back to
$1s\sigma_g$ with lower excited or ground vibrational states.


title:
Evolution of dust grain size distribution by shattering in the
  interstellar medium: robustness and uncertainty

abstract:
  Shattering of dust grains in the interstellar medium is a viable mechanism of
small grain production in galaxies. We examine the robustness or uncertainty in
the theoretical predictions of shattering. We identify $P_1$ (the critical
pressure above which the deformation destroys the original lattice structures)
as the most important quantity in determining the timescale of small grain
production, and confirm that the same $P_1/t$ ($t$ is the duration of
shattering) gives the same grain size distribution [$n(a)$, where $a$ is the
grain radius] after shattering within a factor of 3. The uncertainty in the
fraction of shocked material that is eventually ejected as fragments causes
uncertainties in $n(a)$ by a factor of 1.3 and 1.6 for silicate and
carbonaceous dust, respectively. The size distribution of shattered fragments
have minor effects as long as the power index of the fragment size distribution
is less than ~ 3.5, since the slope of grain size distribution $n(a)$
continuously change by shattering and becomes consistent with $n(a)\propto
a^{-3.5}$. The grain velocities as a function of grain radius can have an
imprint in the grain size distribution especially for carbonaceous dust. We
also show that the formulation of shattering can be simplified without losing
sufficient precision.


title: Topological K-Theory of Complex Projective Spaces

abstract:
  We compute the K-theory of complex projective spaces. There are three major
ingredients: the exact sequence of K-groups, the theory of Chern character and
the Bott Periodicity Theorem.


title: Turnover of the melting line of highly compressed molecular hydrogen

abstract:
  Conventional molecular dynamics simulation has been used to determine melting
temperature of highly compressed classical molecular hydrogen in a wide range
of pressures and temperatures using non-empirical atom-atom potentials
approximation. It is shown that the raise of melting temperature with
increasing pressure becomes more and more smooth and at megabar pressures its
slope goes negative. We discuss the reasons of this turnover and analyze
connection of this effect with the parameters of chemical bonding in H2.


title:
Correlation of paths between distinct vertices in a randomly oriented
  graph

abstract:
  We prove that in a random tournament the events $\{s\rightarrow a\}$ and
$\{t\rightarrow b\}$ are positively correlated, for distinct vertices $a,s,b,t
\in K_n.$ It is also proven that the correlation between the events
$\{s\rightarrow a\}$ and $\{t\rightarrow b\}$ in the random graphs $G(n,p)$ and
$G(n,m)$ with random orientation is positive for every fixed $p>0$ and
sufficiently large $n$ (with $m=\left\lfloor p \binom{n}{2}\right\rfloor$). We
conjecture it to be positive for all $p$ and all $n$. An exact recursion for
$\P(\{s\rightarrow a\} \cap \{t\rightarrow b\})$ in $\gnp$ is given.


title: Towards Dynamic Real-Time Geo-location Databases for TV White Spaces

abstract:
  Recent FCC regulations on TV white spaces allow geo-location databases to be
the sole source of spectrum information for White Space Devices (WSDs).
Geo-location databases protect TV band incumbents by keeping track of TV
transmitters and their protected service areas based on their location,
transmission parameters and sophisticated propagation models. In this article,
we argue that keeping track of both TV transmitters and TV receivers (i.e. TV
sets) can achieve significant improvement in the availability of white spaces.
We first identify wasted spectrum opportunities, both temporal and spatial, due
to the current approach of white spaces detection. We then propose DynaWhite, a
cloud-based architecture that orchestrates the detection and dissemination of
highly-dynamic, real-time, and fine-grained TV white space information.
DynaWhite introduces the next generation of geo-location databases by combining
traditional sensing techniques with a novel unconventional sensing approach
based on the detection of the passive TV receivers using standard cell phones.
We present a quantitative evaluation of the potential gains in white space
availability for large scale deployments of DynaWhite. We finally identify
challenges that need to be addressed in the research community in order to
exploit this potential for leveraging dynamic real-time fine-grained TV white
spaces.


title: Tropicalization and tropical equilibration of chemical reactions

abstract:
  Systems biology uses large networks of biochemical reactions to model the
functioning of biological cells from the molecular to the cellular scale. The
dynamics of dissipative reaction networks with many well separated time scales
can be described as a sequence of successive equilibrations of different
subsets of variables of the system. Polynomial systems with separation are
equilibrated when at least two monomials, of opposite signs, have the same
order of magnitude and dominate the others. These equilibrations and the
corresponding truncated dynamics, obtained by eliminating the dominated terms,
find a natural formulation in tropical analysis and can be used for model
reduction.


title: Simple Search Engine Model: Selective Properties

abstract:
  In this paper we study the relationship between query and search engine by
exploring the selective properties based on a simple search engine. We used the
set theory and utilized the words and terms for defining singleton and
doubleton in the event spaces and then provided their implementation for
proving the existence of the shadow of micro-cluster.


title:
Bit Level Soft Decision Decoding of Triple Parity Reed Solomon Codes
  through Automorphism Groups

abstract:
  This paper discusses bit-level soft decoding of triple-parity Reed-Solomon
(RS) codes through automorphism permutation. A new method for identifying the
automorphism groups of RS binary images is first developed. The new algorithm
runs effectively, and can handle more RS codes and capture more automorphism
groups than the existing ones. Utilizing the automorphism results, a new
bit-level soft-decision decoding algorithm is subsequently developed for
general $(n,n-3,4)$ RS codes. Simulation on $(31,28,4)$ RS codes demonstrates
an impressive gain of more than 1 dB at the bit error rate of $10^{-5}$ over
the existing algorithms.


title: Nilpotency of the b ghost in the non-minimal pure spinor formalism

abstract:
  The b ghost in the non minimal pure spinor formalism is not a fundamental
field. It is based on a complicated chain of operators and proving its
nilpotency is nontrivial. Chandia proved this property in arXiv:1008.1778, but
with an assumption on the non-minimal variables that is not valid in general.
In this work, the b ghost is demonstrated to be nilpotent without this
assumption.


title:
Interface driven reentrant superconductivity in HoNi$_5$-NbN-HoNi$_5$
  nanostructures

abstract:
  Superconductivity (S) and ferromagnetism (F) are probed through transport and
magnetization measurements in nanometer scale HoNi$_5$-NbN (F-S) bilayers and
HoNi$_5$-NbN-HoNi$_5$ (F-S-F) trilayers. The choice of materials has been made
on the basis of their comparable ordering temperatures and strong magnetic
anisotropy in HoNi$_5$. We observe the normal state reentrant behavior in
resistance vs. temperature plots of the F-S-F structures just below the
superconducting transition in the limited range of HoNi$_5$ layer thickness
d$_{HN}$ (20 nm $<$ d$_{HN}$ $<$ 80 nm) when d$_{NbN}$ is fixed at $\simeq$ 10
nm. The reentrance is quenched by increasing the out-of-plane (H$_{\perp}$)
magnetic field and transport current where as in-plane (H$_{\parallel}$) field
of $\leq$ 1500 Oe has no effect on the reentrance. The thermally activated flux
flow characteristics of the S, F-S and F-S-F layers reveal a transition from
collective pinning to single vortex pinning as we place F layers on both sides
of the S film. The origin of the reentrant behavior seen here in the range of
0.74 $\leq$ T$_{Curie}$/T$_C$ $\leq$ 0.92 is attribute to a delicate balance
between the magnetic exchange energy and the condensation energy in the
interfacial regions of the trilayer.


title:
A reinforcement of the Bourgain-Kontorovich's theorem by elementary
  methods II

abstract:
  Zaremba's conjecture (1971) states that every positive integer number $d$ can
be represented as a denominator (continuant) of a finite continued fraction
$\frac{b}{d}=[d_1,d_2,...,d_{k}],$ with all partial quotients
$d_1,d_2,...,d_{k}$ being bounded by an absolute constant $A.$ Recently (in
2011) several new theorems concerning this conjecture were proved by Bourgain
and Kontorovich. The easiest of them states that the set of numbers satisfying
Zaremba's conjecture with A=50 has positive proportion in $\N.$ In this
paper,using only elementary methods, the same theorem is proved with A=5.


title: Signatures of an Encounter Between the G2 Cloud and a Jet from Sgr A*

abstract:
  The recent discovery of the G2 cloud of dense, ionized gas on a trajectory
toward Sgr A*, the black hole at the dynamical center of the Galaxy, offers a
unique opportunity to observe an accretion event onto a massive black hole as
well as to probe its immediate environment. Simulations and models predict
increased X-ray and radio variability resulting from increased accretion driven
by drag on an atmosphere of hot, X-ray emitting gas surrounding Sgr A*. Here,
we present X-ray and radio light curves of the emission resulting from the
potential encounter of the G2 cloud with a relativistic jet from Sgr A*. This
interaction would violently shock a portion of the G2 cloud to temperatures
$\sim 10^8$\,K resulting in bright X-ray emission from the dense, shocked gas
as it adiabatically expands. The 2-10\, keV luminosity may reach $\sim$10 times
the quiescent X-ray flux of Sgr A*. approximately $3\,\lsol$ is emitted above
10\,keV at the peak of the light curve, with significant softening of the
spectrum occurring as the gas subsequently cools. Observations with NuSTAR
would therefore be able to confirm such an event as well as determine the cloud
speed. At radio wavelengths, the associated synchrotron radio emission may
reach levels of a few Jy.


title:
Strong Effects of Cation Vacancies on the Electronic and Dynamical
  Properties of FeO

abstract:
  We report pronounced modifications of electronic and vibrational properties
induced in FeO by cation vacancies, obtained within density functional theory
incorporating strong local Coulomb interactions at Fe atoms. The insulating gap
of FeO is reduced by about 50% due to unoccupied electronic bands introduced by
trivalent Fe ions stabilized by cation vacancies. The changes in the electronic
structure along with atomic displacements induced by cation vacancies affect
strongly phonon dispersions via modified force constants, including those at
atoms beyond nearest neighbors of defects. We demonstrate that theoretical
phonon dispersions and their densities of states reproduce the results of
inelastic neutron and nuclear resonant x-ray scattering experiments \emph{only}
when Fe vacancies and Coulomb interaction $U$ are both included explicitly in
\emph{ab initio} simulations, which also suggests that the electron-phonon
coupling in FeO is strong.


title: Flavour physics from lattice QCD

abstract:
  I review recent results and prospects for improvement in calculations of
hadronic matrix elements relevant to quark flavour phenomenology. I will focus
on key quantities for CKM unitarity triangle analyses and for the study of
discrepancies between experiment and SM predictions for some flavour
observables.


title: Inverse magnetic catalysis and the Polyakov loop

abstract:
  We study the physical mechanism of how an external magnetic field influences
the QCD quark condensate. Two competing mechanisms are identified, both relying
on the interaction between the magnetic field and the low quark modes. While
the coupling to valence quarks enhances the condensate, the interaction with
sea quarks suppresses it in the transition region. The latter `sea effect' acts
by ordering the Polyakov loop and, thereby, reduces the number of small Dirac
eigenmodes and the condensate. It is most effective around the transition
temperature, where the Polyakov loop effective potential is flat and a small
correction to it by the magnetic field can have a significant effect. Around
the critical temperature, the sea suppression overwhelms the valence
enhancement, resulting in a net suppression of the condensate, named inverse
magnetic catalysis. We support this physical picture by lattice simulations
including continuum extrapolated results on the Polyakov loop as a function of
temperature and magnetic field. We argue that taking into account the increase
in the Polyakov loop and its interaction with the low-lying modes is essential
to obtain the full physical picture, and should be incorporated in effective
models for the description of QCD in magnetic fields in the transition region.


title:
Weighted-ensemble Brownian dynamics simulation: Sampling of rare events
  in non-equilibrium systems

abstract:
  We provide an algorithm based on weighted-ensemble (WE) methods, to
accurately sample systems at steady state. Applying our method to different
one- and two-dimensional models, we succeed to calculate steady state
probabilities of order $10^{-300}$ and reproduce Arrhenius law for rates of
order $10^{-280}$. Special attention is payed to the simulation of
non-potential systems where no detailed balance assumption exists. For this
large class of stochastic systems, the stationary probability distribution
density is often unknown and cannot be used as preknowledge during the
simulation. We compare the algorithms efficiency with standard Brownian
dynamics simulations and other WE methods.


title:
A 125 GeV Scalar Boson and SU(N_{TC})\otimes SU(3)_{{}_{L}}\otimes
  U(1)_{{}_{X}} models

abstract:
  We verify that SU(N)_{{}_{TC}}\otimes SU(3)_{{}_{L}}\otimes U(1)_{{}_{X}}
models, where the gauge symmetry breaking is totally dynamical and promoted by
the non-Abelian technicolor (TC) group and the strong Abelian interactions, are
quite constrained by the LHC data. The theory contains a T quark self-energy
involving the mixing between the neutral gauge bosons, which introduces the
coupling between the light and heavy composite scalar bosons of the model. We
determine the lightest scalar boson mass for these models from an effective
action for composite operators, assuming details about the dynamics of the
strong interaction theories. Comparing the value of this mass with the ATLAS
and CMS observation of a new boson with a mass M_{\phi} \sim 125GeV and
considering the lower bound determined by the LHC Collaborations on the heavy
neutral gauge boson (Z^\prime) present in these models, we can establish
constraints on the possible models. For example, if SU(N)_{{}_{TC}}\equiv
SU(2)_{{}_{TC}}, with technifermions in the fundamental representation, the
model barely survives the confrontation with the LHC data.


title: Mixed non-Gaussianity in multiple-DBI inflation

abstract:
  We study a model of multiple-field DBI inflation leading to mixed form of
primordial non-Gaussianity, including equilateral and local bispectrum shapes.
We present a general formalism based on the Hamilton-Jacobi approach, allowing
us to go beyond slow-roll, combining the three-point function for the fields at
Hubble-exit with the non-linear evolution of super-Hubble scales. We are able
to obtain analytic results by taking a separable Ansatz for the Hubble rate. We
find general expressions for both the equilateral and local type
non-Gaussianity parameter fNL. The equilateral non-Gaussianity includes the
usual enhancement for small sound speeds, but multiplied by an analytic factor
which can lead to a suppression. We illustrate our results with two scenarios.
In the first model, previously found to have detectable local non-Gaussianity,
we find that the equilateral signal is not sufficiently suppressed to evade
current observational bounds. In our second scenario we construct a model which
exhibits both a detectable equilateral fNL and a negative local fNL.


title:
Two dimensional nonlinear cylindrical equilibria with reversed magnetic
  shear and sheared flow

abstract:
  Nonlinear tranlational symmetric equilibria with up to quartic flux terms in
the free functions, reversed magnetic shear and sheared flow are constructed in
two ways: i) quasianalytically by an ansatz which reduces the pertinent
generalized Grad-Shafranov equation to a set of ordinary differential equations
and algebraic constraints which is then solved numerically, and ii) completely
numerically by prescribing analytically a boundary having an X-point. The
equilibrium characteristics are then examined by means of the pressure, safety
factor, current density and electric field. For flows parallel to the magnetic
field the stability of the equilibria constructed is also examined by applying
a sufficient condition. It turns out that the equilibrium nonlinearity has a
stabilizing impact which is slightly enhanced by the sheared flow. In addition,
the results indicate that the stability is affected by the up-down asymmetry.


title:
Hubble Space Telescope ACS Imaging of the GOALS Sample: Quantitative
  Structural Properties of Nearby Luminous Infrared Galaxies with L_IR >
  10^{11.4} L_sun

abstract:
  A {\it Hubble Space Telescope} ({\it HST}) / Advanced Camera for Surveys
(ACS) study of the structural properties of 85 luminous and ultraluminous
($L_{\rm IR} > 10^{11.4}$ L$_\odot$) infrared galaxies (LIRGs and ULIRGs) in
the Great Observatories All-sky LIRG Survey (GOALS) sample is presented.
Two-dimensional GALFIT analysis has been performed on F814W "{\it I}-band"
images to decompose each galaxy, as appropriate, into bulge, disk, central PSF
and stellar bar components. The fraction of bulge-less disk systems is observed
to be higher in LIRGs (35%) than in ULIRGs (20%), with the disk+bulge systems
making up the dominant fraction of both LIRGs (55%) and ULIRGs (45%). Further,
bulge+disk systems are the dominant late-stage merger galaxy type and are the
dominant type for LIRGs and ULIRGs at almost every stage of galaxy-galaxy
nuclear separation. The mean {\it I}-band host absolute magnitude of the GOALS
galaxies is $-22.64\pm$0.62 mag (1.8$^{+1.4}_{-0.4}$ L$^*_I$), and the mean
bulge absolute magnitude in GOALS galaxies is about 1.1 magnitude fainter than
the mean host magnitude. Almost all ULIRGs have bulge magnitudes at the high
end (-20.6 to - 23.5 mag) of the GOALS bulge magnitude range. Mass ratios in
the GOALS binary systems are consistent with most of the galaxies being the
result of major mergers, and an examination of the residual-to-host intensity
ratios in GOALS binary systems suggests that smaller companions suffer more
tidal distortion than the larger companions. We find approximately twice as
many bars in GOALS disk+bulge systems (32.8%) than in pure-disk mergers (15.9%)
but most of the disk+bulge systems that contain bars are disk-dominated with
small bulges. The bar-to-host intensity ratio, bar half-light radius, and bar
ellipticity in GOALS galaxies are similar to those found in nearby spiral
galaxies.(abridged)


title:
Erdelyi-Kober Fractional Integral Operators from a Statistical
  Perspective -I

abstract:
  In this article we examine the densities of a product and a ratio of two real
positive scalar random variables $x_1$ and $x_2$, which are statistically
independently distributed, and we consider the density of the product
$u_1=x_1x_2$ as well as the density of the ratio $u_2={{x_2}\over{x_1}}$ and
show that Kober operator of the second kind is available as the density of
$u_1$ and Kober operator of the first kind is available as the density of $u_2$
when $x_1$ has a type-1 beta density and $x_2$ has an arbitrary density. We
also give interpretations of Kober operators of the second and first kind as
Mellin convolution for a product and ratio respectively. Then we look at
various types of generalizations of the idea thereby obtaining a large
collection of operators which can all be called generalized Kober operators.
One of the generalizations considered is the pathway idea where one can move
from one family of operators to another family and yet another family and
eventually end up with an exponential form. Common generalizations in terms of
a Gauss' hypergeometric series is also given a statistical interpretation and
put on a more general structure so that the standard generalizations given by
various authors, including Saigo operators, are given statistical
interpretations and are derivable as special cases of the general structure
considered in this article.


title:
Erdelyi-Kober Fractional Integral Operators from a Statistical
  Perspective -II

abstract:
  In this article we examine the densities of a product and a ratio of two real
positive definite matrix-variate random variables $X_1$ and $X_2$, which are
statistically independently distributed, and we consider the density of the
product $U_1=X_2^{1\over2}X_1X_2^{1\over2}$ as well as the density of the ratio
$U_2=X_2^{1\over2}X_1^{-1}X_2^{1\over2}$. We define matrix-variate Kober
fractional integral operators of the first and second kinds from a statistical
perspective, making use of the derivation in the predecessor of this paper for
the scalar variable case, by deriving the densities of products and ratios
where one variable has a matrix-variate type-1 beta density and the other
variable has an arbitrary density. Various types of generalizations are
considered, by using pathway models, by appending matrix variate hypergeometric
series etc. During this process matrix-variate Saigo operator and other
operators are also defined and properties studied.


title:
Erdelyi-Kober Fractional Integral Operators from a Statistical
  Perspective -III

abstract:
  In this article we define Kober fractional integral operators in the
multivariable case. First we consider one sequence of independent random
variables and an arbitrary function, which can act as the joint density of
another sequence of random variables. Then we define a concept, analogous to
the concept of Kober operators in the scalar variable case. This extension is
achieved by using statistical techniques and the representation gives an
interpretation in terms of a joint statistical density. Then we look at two
sets of random variables where between the sets they are independently
distributed but within each set they are dependent. Again extensions of Kober
fractional integral operator are considered. Several such statistical
interpretations are given for Kober operators in the multivariable case.


title:
Erdelyi-Kober Fractional Integral Operators from a Statistical
  Perspective -IV

abstract:
  In the preceding articles we considered fractional integral transforms
involving one real scalar variable, one real matrix variable and real scalar
multivariable case. In the present paper we consider the multivariable case
when the arbitrary function is a real-valued scalar function of many $p\times
p$ real matrix variables $X_1,...,X_k$. Extension of all standard fractional
integral operators to the cases of many matrix variables is considered, along
with interesting special cases and generalized matrix transforms.


title:
Probability distribution over some phenomenological models in the matrix
  model compactified on a torus

abstract:
  We study some phenomenological models in a matrix model corresponding to the
IIB matrix model compactified on a six-dimensional torus with magnetic fluxes.
Extending our previous works, we examine a wider class of models: a
Pati-Salam-like model with a gauge group U(4)*U_L(2)*U_R(2), and models where
the gauge group U(4) is broken down to U_c(3)*U(1) and/or U_R(2) is broken down
to U(1)^2. We find all the matrix configurations that yield matter content of
all the phenomenological models whose gauge group is a subgroup of U(8). We
then estimate semiclassically a probability distribution for the appearance of
the phenomenological models.


title: Fractional Operators in the Matrix Variate Case

abstract:
  Fractional integral operators connected with real-valued scalar functions of
matrix argument are applied in problems of mathematics, statistics and natural
sciences. In this article we start considering the case of a Gauss
hypergeometric function with the argument being a rectangular matrix.
Subsequently some fractional integral operators are introduced which complement
these results available on fractional operators in the matrix variate cases.
Several properties and limiting forms are derived. Then the pathway idea is
incorporated to move among several different functional forms. When these are
used as models for problems in the natural sciences then these can cover the
ideal situations, neighborhoods, in between stages and paths leading to optimal
situations.


title:
Optimal Vaccine Allocation to Control Epidemic Outbreaks in Arbitrary
  Networks

abstract:
  We consider the problem of controlling the propagation of an epidemic
outbreak in an arbitrary contact network by distributing vaccination resources
throughout the network. We analyze a networked version of the
Susceptible-Infected-Susceptible (SIS) epidemic model when individuals in the
network present different levels of susceptibility to the epidemic. In this
context, controlling the spread of an epidemic outbreak can be written as a
spectral condition involving the eigenvalues of a matrix that depends on the
network structure and the parameters of the model. We study the problem of
finding the optimal distribution of vaccines throughout the network to control
the spread of an epidemic outbreak. We propose a convex framework to find
cost-optimal distribution of vaccination resources when different levels of
vaccination are allowed. We also propose a greedy approach with quality
guarantees for the case of all-or-nothing vaccination. We illustrate our
approaches with numerical simulations in a real social network.


title: Commuting Matrix Solutions of PQCD Evolution Equations

abstract:
  A method of obtaining parton distributions directly from data is revealed in
this series. In the process, the first step would be developing appropriate
matrix solutions of the evolution equations in $x$ space. A division into
commuting and non-commuting matrix solutions has been made. Here,
well-developed commuting matrix solutions are presented. Results for finite LO
evolution match those of standard LO sets. There is a real potential of doing
non-parametric data analysis.


title:
Super quantum probabilities and three-slit experiments -- Wright's
  pentagon state and the Popescu-Rohrlich box require third-order interference

abstract:
  Quantum probabilities differ from classical ones in many ways, e.g., by
violating the well-known Bell and CHSH inequalities or another simple
inequality due to R. Wright. The latter one has recently regained attention
because of its equivalence to a novel noncontextual inequality by Klyachko et
al. On the other hand, quantum probabilities still obey many limitations which
need not hold any more in more general probabilistic theories (super quantum
probabilities). Wright, Popescu and Rohrlich identified states which are
included in such theories, but impossible in quantum mechanics, and they showed
this using its Hilbert space formalism. Recently, Fritz et al. and Cabello
detected that the impossibility of these states can be derived from very
general principles (local orthogonality and global exclusive disjunction,
respectively) without using Hilbert space techniques. In the paper, an
alternative derivation from rather different phyisical principles will be
presented. These are a reasonable calculus of conditional probability (i.e., a
model for the quantum measurement process) and the absence of third-order
interference. The concept of third-order interference was introduced by Sorkin
who also recognized its impossibility in quantum mechanics.


title: $l_{2,p}$ Matrix Norm and Its Application in Feature Selection

abstract:
  Recently, $l_{2,1}$ matrix norm has been widely applied to many areas such as
computer vision, pattern recognition, biological study and etc. As an extension
of $l_1$ vector norm, the mixed $l_{2,1}$ matrix norm is often used to find
jointly sparse solutions. Moreover, an efficient iterative algorithm has been
designed to solve $l_{2,1}$-norm involved minimizations. Actually,
computational studies have showed that $l_p$-regularization ($0<p<1$) is
sparser than $l_1$-regularization, but the extension to matrix norm has been
seldom considered. This paper presents a definition of mixed $l_{2,p}$ $(p\in
(0, 1])$ matrix pseudo norm which is thought as both generalizations of $l_p$
vector norm to matrix and $l_{2,1}$-norm to nonconvex cases $(0<p<1)$.
Fortunately, an efficient unified algorithm is proposed to solve the induced
$l_{2,p}$-norm $(p\in (0, 1])$ optimization problems. The convergence can also
be uniformly demonstrated for all $p\in (0, 1]$. Typical $p\in (0,1]$ are
applied to select features in computational biology and the experimental
results show that some choices of $0<p<1$ do improve the sparse pattern of
using $p=1$.


title: Measuring the Top Quark Mass using Kinematic Endpoints

abstract:
  We report on a simultaneous measurement of the top quark, W boson, and
neutrino masses in $t\bar{t}$ dilepton decays with $4.98 \mathrm{fb}^{-1}$ of
data from the CMS experiment. The analysis is based on endpoint determinations
in kinematic distributions. In addition to the unconstrained fit for three
masses, the neutrino and W boson masses can be constrained to standard values;
in the maximally constrained fit, the top quark mass is found to be $M_t =
173.9 \pm 0.9 (stat) {}^{+1.2}_{-1.8} (syst) $ GeV.


title: Signed fundamental domains for totally real number fields

abstract:
  We give a signed fundamental domain for the action on $\mathbb{R}^n_+$ of the
totally positive units $E_+$ of a totally real number field $k$ of degree $n$.
The domain $\big\{(C_\sigma,w_\sigma) \big\}_\sigma$ is signed since the net
number of its intersections with any $E_+$-orbit is 1, i. e. for any $x\in
\mathbb{R}^n_+$, $$ \sum_{\sigma\in S_{n-1}} \sum_{\varepsilon\in E_+}
w_\sigma\chi^{\phantom{1}}_{C_\sigma}(\varepsilon x) = 1. $$ Here
$\chi_{C_\sigma}$ is the characteristic function of $C_\sigma$, $w_\sigma=\pm1$
is a natural orientation of the $n$-dimensional $k$-rational cone
$C_\sigma\subset\mathbb{R}^n_+$, and the inner sum is actually finite. Signed
fundamental domains are as useful as Shintani's true ones for the purpose of
calculating abelian $L$-functions. They have the advantage of being easily
constructed from any set of fundamental units, whereas in practice there is no
algorithm producing Shintani's $k$-rational cones. Our proof uses algebraic
topology on the quotient manifold $\mathbb{R}^n_+/E_+$. The invariance of the
topological degree under homotopy allows us to control the deformation of a
crooked fundamental domain into nice straight cones. Crossings may occur during
the homotopy, leading to the need to subtract some cones.


title:
Master thesis: Growth and Self-Organization Processes in Directed Social
  Network

abstract:
  Large dataset collected from Ubuntu chat channel is studied as a complex
dynamical system with emergent collective behaviour of users. With the
appropriate network mappings we examined wealthy topological structure of
Ubuntu network. The structure of this network is determined by computing
different topological measures. The directed, weighted network, which is a
suitable representation of the dataset from Ubuntu chat channel is
characterized with power law dependencies of various quantities, hierarchical
organization and disassortative mixing patterns. Beyond the topological
features, the emergent collective state is further quantified by analysis of
time series of users activities driven by emotions. Analysis of time series
reveals self-organized dynamics with long-range temporal correlations in user
actions.


title: Half-quantum linear algebra

abstract: The Cayley--Hamilton--Newton theorem for half-quantum matrices is proven.


title: On the exceptional set for absolute continuity of Bernoulli convolutions

abstract:
  We prove that the set of exceptional $\lambda\in (1/2,1)$ such that the
associated Bernoulli convolution is singular has zero Hausdorff dimension, and
likewise for biased Bernoulli convolutions, with the exceptional set
independent of the bias. This improves previous results by Erd\"os, Kahane,
Solomyak, Peres and Schlag, and Hochman. A theorem of this kind is also
obtained for convolutions of homogeneous self-similar measures. The proofs are
very short, and rely on old and new results on the dimensions of self-similar
measures and their convolutions, and the decay of their Fourier transform.


title: On regularity of the discrete Hardy-Littlewood maximal function

abstract:
  We extend the recent boundedness result of Kurka for Hardy-Littlewood maximal
function to discrete setting.


title: Optically induced currents in dielectrics as a nonlinear optical effect

abstract:
  We show that recently observed DC currents produced by below-the-bandgap
femtosecond pulses [1] can be explained as nonlinear optical effects based on
multi-photon quantum interference and creation of an asymmetric distribution of
virtual carriers in the conduction and valence bands. We establish an
unambiguous connection between the nonlinear optical conductivity responsible
for the observed DC currents and charges and the odd-order nonlinear optical
susceptibilities of the material. Using a single well known measured value of
the third order susceptibility (nonlinear index) of SiO2 we obtain excellent
agreement with all the experimental data of [1] without resorting to extensive
numerical modeling. A clear physical picture of the origin of the photo-induced
currents and charges shows that the versatility of ultrafast (virtual)
nonlinear optical phenomena extends even further than had been previously
thought.


title: Distances in critical long range percolation

abstract:
  We study the long range percolation model on $\mathbb{Z}$ where sites $i$ and
$j$ are connected with probability $\beta |i-j|^{-s}$. Graph distances are now
well understood for all exponents $s$ except in the case $s=2$ where the model
exhibits non-trivial self-similar scaling. Establishing a conjecture of
Benjamini and Berger \cite{BenBer:01}, we prove that the typical distance from
site 0 to $n$ grows as a power law $n^{\theta(\beta)}$ up to a multiplicative
constant for some exponent $0<\theta(\beta)<1$ as does the diameter of the
graph on a box of length $n$.


title:
An X-rays Survey of the Young Stellar Population of the Lynds 1641 and
  Iota Orionis Regions

abstract:
  We present an XMM-Newton survey of the part of Orion A cloud south of the
Orion Nebula. This survey includes the Lynds 1641 (L1641) dark cloud, a region
of the Orion A cloud with very few massive stars and hence a relatively low
ambient UV flux, and the region around the O9 III star Iota Orionis. In
addition to proprietary data, we used archival XMM data of the Orion Nebula
Cluster (ONC) to extend our analysis to a major fraction of the Orion A cloud.
We have detected 1060 X-ray sources in L1641 and Iota Ori region. About 94% of
the sources have 2MASS & Spitzer counterparts, 204 and 23 being Class II and
Class I or protostars objects, respectively. In addition, we have identified
489 X-ray sources as counterparts to Class III candidates, given they are
bright in X-rays and appear as normal photospheres at mid-IR wavelengths. The
remaining 205 X-ray sources are likely distant AGNs or other galactic sources
not related to Orion A. We find that Class III candidates appear more
concentrated in two main clusters in L1641. The first cluster of Class III
stars is found toward the northern part of L1641, concentrated around Iota Ori.
The stars in this cluster are more evolved than those in the Orion Nebula. We
estimate a distance of 300-320 pc for this cluster and thus it is closer than
the Orion A cloud. Another cluster rich in Class III stars is located in L1641
South and appears to be a slightly older cluster embedded in the Orion A cloud.
Furthermore, other evolved Class III stars are found north of the ONC toward
NGC 1977.


title:
Aligning sequence reads, clone sequences and assembly contigs with
  BWA-MEM

abstract:
  Summary: BWA-MEM is a new alignment algorithm for aligning sequence reads or
long query sequences against a large reference genome such as human. It
automatically chooses between local and end-to-end alignments, supports
paired-end reads and performs chimeric alignment. The algorithm is robust to
sequencing errors and applicable to a wide range of sequence lengths from 70bp
to a few megabases. For mapping 100bp sequences, BWA-MEM shows better
performance than several state-of-art read aligners to date.
  Availability and implementation: BWA-MEM is implemented as a component of
BWA, which is available at http://github.com/lh3/bwa.
  Contact: hengli@broadinstitute.org


title:
Multiple scales and singular limits for compressible rotating fluids
  with general initial data

abstract:
  We study the singular limit of a rotating compressible fluid described by a
scaled barotropic Navier-Stokes system, where the Rossby number, the Mach
number and the Froude number tend to 0 in a particular mutual rate while the
Reynolds number tends to infinity. The inviscid planar Euler system is
identified as the limit problem. The proof is based on the application of the
method of relative entropies and careful analysis of oscillatory integrals
describing the propagation of Rossby-acoustic waves.


title:
Exact solution of the 1D Riemann problem in Newtonian and relativistic
  hydrodynamics

abstract:
  Some of the most interesting scenarios that can be studied in astrophysics,
contain fluids and plasma moving under the influence of strong gravitational
fields. To study these problems it is required to implement numerical
algorithms robust enough to deal with the equations describing such scenarios,
which usually involve hydrodynamical shocks. It is traditional that the first
problem a student willing to develop research in this area is to numerically
solve the one dimensional Riemann problem, both Newtonian and relativistic.
Even a more basic requirement is the construction of the exact solution to this
problem in order to verify that the numerical implementations are correct. We
describe in this paper the construction of the exact solution and a detailed
procedure of its implementation.

categories: astro-ph.HE gr-qc physics.comp-ph physics.flu-dyn


title:
Effects of the Carnahan-Starling free energy within theories of fluids
  with short-range attraction

abstract:
  Within the Free-Volume Asakura-Oosawa-Vrij (FVAO) theory of colloid-polymer
mixtures, we show that unphysical gas-liquid binodals predicted in the regime
of small attraction range (i.e. polymer size) are caused in part by the use of
the Carnahan-Starling (CS) hard sphere (HS) reference free energy. Replacement
of the CS expression with an alternative dramatically affects predicted phase
behaviour and, for polydisperse colloid, the resultant fractionation
predictions. Although short-range attractions render FVAO, as a perturbative
HS-based theory, less accurate anyway, we argue that the particular effects of
CS in this regime are an important consideration -- usually ignored -- in the
evaluation of such theories. We refer to a variety of literature exhibiting
similarly inaccurate gas-liquid binodals, and suggest CS's status as the de
facto choice of hard sphere reference should be carefully considered where
short-range attractions are present.


title: Multi-level selection in biology

abstract:
  Okasha (2006) proposed distinguishing aspects of selection: those based in
particle level traits (MSL1), and those based in group level traits (MSL2). It
is proposed here that MSL1 can usefully be further split into two aspects, one
(MLS1E) representing selection of particles based in their individual
interaction with environmental properties, and one (MLS1G) representing Multi
Level Selection of particles based in their relation to group properties.
Similarly MSL2 can be split into two parts based in this distinction. This
splitting enables a characterisation of how emergent group properties can
affect particle selection, and thus affect group traits that are important for
survival. This proposal is illustrated by considering a key aspect of animal
and human life, namely the formation of social groups, which greatly enhances
survival prospects. The biological mechanism that underlies such group
formation is the existence of innate primary emotional systems studied by
Panksepp (1998), effective through the ascending systems in the brain that
diffuse neurotransmitters such as dopamine and norepinephrine through the
cortex. Evolutionary emergence of such brain mechanisms, and hence the
emergence of social groups, can only result from multi-level selection
characterised by the combination of MSL2 and MLS1G. The distinctions proposed
here should be useful in other contexts.


title:
Invariant geodesics in the curve complex under point-pushing
  pseudo-Anosov mapping classes

abstract:
  Let $S$ be a closed Riemann surface of genus $p>1$ with one point removed. In
this paper, we identify those point-pushing pseudo-Anosov maps on $S$ that
preserve at least one bi-infinite geodesic in the curve complex.