title:
UVMULTIFIT: A versatile tool for fitting astronomical radio
  interferometric data

abstract:
  The analysis of astronomical interferometric data is often performed on the
images obtained after deconvolution of the interferometer's point spread
function (PSF). This strategy can be understood (especially for cases of sparse
arrays) as fitting models to models, since the deconvolved images are already
non-unique model representations of the actual data (i.e., the visibilities).
Indeed, the interferometric images may be affected by visibility gridding,
weighting schemes (e.g., natural vs. uniform), and the particulars of the
(non-linear) deconvolution algorithms. Fitting models to the direct
interferometric observables (i.e., the visibilities) is preferable in the cases
of simple (analytical) sky intensity distributions. In this paper, we present
UVMULTIFIT, a versatile library for fitting visibility data, implemented in a
Python-based framework. Our software is currently based on the CASA package,
but can be easily adapted to other analysis packages, provided they have a
Python API. We have tested the software with synthetic data, as well as with
real observations. In some cases (e.g., sources with sizes smaller than the
diffraction limit of the interferometer), the results from the fit to the
visibilities (e.g., spectra of close by sources) are far superior to the output
obtained from the mere analysis of the deconvolved images. UVMULTIFIT is a
powerful improvement of existing tasks to extract the maximum amount of
information from visibility data, especially in cases close to the
sensitivity/resolution limits of interferometric observations.


title: Lost and found: the radial quantum number of Laguerre-Gauss modes

abstract:
  We introduce an operator linked with the radial index in the Laguerre-Gauss
modes of a two-dimensional harmonic oscillator in cylindrical coordinates. We
discuss ladder operators for this variable, and confirm that they obey the
commutation relations of the su(1,1) algebra. Using this fact, we examine how
basic quantum optical concepts can be recast in terms of radial modes.


title:
Topological insulator in junction with ferromagnets: quantum Hall
  effects

abstract:
  The ferromagnet-topological insulator-ferromagnet (FM-TI-FM) junction
exhibits thermal and electrical quantum Hall effects. The generated Hall
voltage and transverse temperature gradient can be controlled by the directions
of magnetizations in the FM leads, which inspires the use of FM-TI-FM junctions
as electrical and as heat switches in spintronic devices. Thermal and
electrical Hall coefficients are calculated as functions of the magnetization
directions in ferromagnets and the spin-relaxation time in TI. Both the Hall
voltage and the transverse temperature gradient decrease but are not completely
suppressed even at very short spin-relaxation times. The Hall coefficients turn
out to be independent of the spin-relaxation time for symmetric configuration
of FM leads.


title:
Hairy black holes sourced by a conformally coupled scalar field in D
  dimensions

abstract:
  There exist well-known no-hair theorems forbidding the existence of hairy
black hole solutions in general relativity coupled to a scalar conformal field
theory in asymptotically flat space. Even in the presence of cosmological
constant, where no-hair theorems can usually be circumvented and black holes
with conformal scalar hair were shown to exist in dimensions three and four,
no-go results were reported for D>4. In this paper we prove that these
obstructions can be evaded and we answer in the affirmative a question that
remained open: Whether hairy black holes do exist in general relativity sourced
by a conformally coupled scalar field in arbitrary dimensions. We find the
analytic black hole solution in arbitrary dimension D>4, which exhibits a
backreacting scalar hair that is regular everywhere outside and on the horizon.
The metric asymptotes to (Anti-)de Sitter spacetime at large distance and
admits spherical horizon as well as horizon of a different topology. We also
find analytic solutions when higher-curvature corrections O(R^n) of arbitrary
order n are included in the gravity action.


title: Marginal Pseudo-Likelihood Learning of Markov Network structures

abstract:
  Undirected graphical models known as Markov networks are popular for a wide
variety of applications ranging from statistical physics to computational
biology. Traditionally, learning of the network structure has been done under
the assumption of chordality which ensures that efficient scoring methods can
be used. In general, non-chordal graphs have intractable normalizing constants
which renders the calculation of Bayesian and other scores difficult beyond
very small-scale systems. Recently, there has been a surge of interest towards
the use of regularized pseudo-likelihood methods for structural learning of
large-scale Markov network models, as such an approach avoids the assumption of
chordality. The currently available methods typically necessitate the use of a
tuning parameter to adapt the level of regularization for a particular dataset,
which can be optimized for example by cross-validation. Here we introduce a
Bayesian version of pseudo-likelihood scoring of Markov networks, which enables
an automatic regularization through marginalization over the nuisance
parameters in the model. We prove consistency of the resulting MPL estimator
for the network structure via comparison with the pseudo information criterion.
Identification of the MPL-optimal network on a prescanned graph space is
considered with both greedy hill climbing and exact pseudo-Boolean optimization
algorithms. We find that for reasonable sample sizes the hill climbing approach
most often identifies networks that are at a negligible distance from the
restricted global optimum. Using synthetic and existing benchmark networks, the
marginal pseudo-likelihood method is shown to generally perform favorably
against recent popular inference methods for Markov networks.


title:
The White Dwarfs within 25 Parsecs of the Sun: Kinematics and
  Spectroscopic Subtypes

abstract:
  We present the fractional distribution of spectroscopic subtypes, range and
distribution of surface temperatures, and kinematical properties of the white
dwarfs within 25pc of the sun. There is no convincing evidence of halo white
dwarfs in the total 25 pc sample of 224 white dwarfs. There is also little to
suggest the presence of genuine thick disk subcomponent members within 25
parsecs. It appears that the entire 25 pc sample likely belong to the thin
disk. We also find no significant kinematic differences with respect to
spectroscopic subtypes. The total DA to non-DA ratio of the 25 pc sample is
1.8, a manifestation of deepening envelope convection which transforms DA stars
with sufficiently thin H surface layers into non-DAs. We compare this ratio
with the results of other studies. We find that at least 11% of the white
dwarfs within 25 parsecs of the sun (the DAZ and DZ stars) have photospheric
metals that likely originate from accretion of circumstellar material (debris
disks) around them. If this interpretation is correct, then it suggests the
possibility that a similar percentage have planets, asteroid-like bodies or
debris disks orbiting them. Our volume-limited sample reveals a pileup of DC
white dwarfs at the well-known cutoff in DQ white dwarfs at Tef about 6000K.
Mindful of small number statistics, we speculate on its possible evolutionary
significance. We find that the incidence of magnetic white dwarfs in the 25 pc
sample is at least 8%, in our volume-limited sample, dominated by cool white
dwarfs. We derive approximate formation rates of DB and DQ degenerates and
present a preliminary test of the evolutionary scenario that all cooling DB
stars become DQ white dwarfs via helium convective dredge-up with the diffusion
tail of carbon extending upward from their cores.


title:
Semi-microscopic folding model for the description of two-body halo
  nuclei

abstract:
  One-neutron halo nuclei, composed by a weakly-bound particle coupled to a
core nucleus, are studied within a particle-plus-core model. A semi-microscopic
method to generate the two-body Hamiltonian of such a system, including core
excitation, is proposed. The method consists in generating the spin-independent
part of the valence-core interaction using a single-folding procedure,
convoluting a realistic nucleon-nucleon (NN) interaction with the core
transition densities. The latter are calculated with the Antisymetrized
Molecular Dynamics (AMD) method. The prescription is applied to the well known
halo nucleus, $^{11}$Be, as a test case. The results show an important
predictive power that opens a door to the understanding of other lesser known
halo nuclei. In order to show the potential usefulness of the method, it is
applied to analyze the structure of $^{19}$C.


title:
Dominant role of oxygen vacancies in electrical properties of unannealed
  LaAlO3/SrTiO3 interfaces

abstract:
  We report that in unannealed LaAlO3/SrTiO3 (LAO/STO) heterostructures the
critical thickness for the appearance of the two-dimensional electron gas can
be less than 4 unit cell (uc), the interface is conducting even for STO
substrates with mixed terminations and the low-temperature resistance upturn in
LAO/STO heterostructures with thick LAO layers strongly depends on laser
fluence. Our experimental results provide fundamental insights into the
different roles played by oxygen vacancies and polarization catastrophe in the
two-dimensional electron gas in crystalline LAO/STO heterostructures.


title:
Influence of a drag force on linear transport in low-density gases.
  Stability analysis

abstract:
  The transport coefficients of a dilute classical gas in the presence of a
drag force proportional to the velocity of the particle are determined from the
Boltzmann equation. The viscous drag force could model the friction of solid
particles with a surrounding fluid (interstitial gas phase). First, when the
drag force is the only external action on the state of the system, the
Boltzmann equation admits a Maxwellian solution $f_0(\mathbf{v},t)$ with a
time-dependent temperature. Then, the Boltzmann equation is solved by means of
the Chapman-Enskog expansion around the local version of the distribution $f_0$
to obtain the relevant transport coefficients of the system: the shear
viscosity $\eta$, the thermal conductivity $\kappa$, and a new transport
coefficient $\mu$ (which is also present in granular gases) relating the heat
flux with the density gradient. The results indicate that while $\eta$ is not
affected by the drag force, the impact of this force on the transport
coefficients $\kappa$ and $\mu$ may be significant. Finally, a stability
analysis of the linear hydrodynamic equations with respect to the
time-dependent equilibrium state is performed, showing that the onset of
instability is associated with the transversal shear mode that could be
unstable for wave numbers smaller than a certain critical wave number.


title:
The ALHAMBRA survey: an empirical estimation of the cosmic variance for
  merger fraction studies based on close pairs

abstract:
  Our goal is to estimate empirically, for the first time, the cosmic variance
that affects merger fraction studies based on close pairs. We compute the
merger fraction from photometric redshift close pairs with 10h^-1 kpc <= rp <=
50h^-1 kpc and Dv <= 500 km/s, and measure it in the 48 sub-fields of the
ALHAMBRA survey. We study the distribution of the measured merger fractions,
that follow a log-normal function, and estimate the cosmic variance sigma_v as
the intrinsic dispersion of the observed distribution. We develop a maximum
likelihood estimator to measure a reliable sigma_v and avoid the dispersion due
to the observational errors (including the Poisson shot noise term). The cosmic
variance of the merger fraction depends mainly on (i) the number density of the
populations under study, both for the principal (n_1) and the companion (n_2)
galaxy in the close pair, and (ii) the probed cosmic volume V_c. We find a
significant dependence on neither the search radius used to define close
companions, the redshift, nor the physical selection (luminosity or stellar
mass) of the samples. We provide a parametrisation of the cosmic variance with
n_1, n_2, and V_c, sigma_v = 0.48 n_1^{-0.54} V_c^{-0.48} (n_2/n_1)^{-0.37}.
Thanks to this prescription, future merger fraction studies based on close
pairs could account properly for the cosmic variance on their results.


title: A Review of Verbal and Non-Verbal Human-Robot Interactive Communication

abstract:
  In this paper, an overview of human-robot interactive communication is
presented, covering verbal as well as non-verbal aspects of human-robot
interaction. Following a historical introduction, and motivation towards fluid
human-robot communication, ten desiderata are proposed, which provide an
organizational axis both of recent as well as of future research on human-robot
communication. Then, the ten desiderata are examined in detail, culminating to
a unifying discussion, and a forward-looking conclusion.


title: The fundamental theorem of cubical small cancellation theory

abstract:
  We give a new proof of the main theorem in the theory of C(6) small
cancellation complexes. We prove the fundamental theorem of cubical small
cancellation theory for C(9) cubical small cancellation complexes.


title: Supersymmetry generated one-way invisible PT-symmetric optical crystals

abstract:
  We use supersymmetry transformations to design transparent and one-way
reflectionless (thus unidirectionally invisible) complex crystals with balanced
gain and loss profiles. The scattering coefficients are investigated using the
transfer matrix approach. It is shown that the amount of reflection from the
left can be made arbitrarily close to zero whereas the reflection from the
right is enhanced arbitrarily (or vice versa).


title: Quantum speedup for active learning agents

abstract:
  Can quantum mechanics help us in building intelligent robots and agents? One
of the defining characteristics of intelligent behavior is the capacity to
learn from experience. However, a major bottleneck for agents to learn in any
real-life situation is the size and complexity of the corresponding task
environment. Owing to, e.g., a large space of possible strategies, learning is
typically slow. Even for a moderate task environment, it may simply take too
long to rationally respond to a given situation. If the environment is
impatient, allowing only a certain time for a response, an agent may then be
unable to cope with the situation and to learn at all. Here we show that
quantum physics can help and provide a significant speed-up for active learning
as a genuine problem of artificial intelligence. We introduce a large class of
quantum learning agents for which we show a quadratic boost in their active
learning efficiency over their classical analogues. This result will be
particularly relevant for applications involving complex task environments.


title: Naturally light dilatons from nearly marginal deformations

abstract:
  We discuss the presence of a light dilaton in CFTs deformed by a
nearly-marginal operator O, in the holographic realizations consisting of
confining RG flows that end on a soft wall. Generically, the deformations
induce a condensate <O>, and the dilaton mode can be identified as the
fluctuation of <O>. We obtain a mass formula for the dilaton as a certain
average along the RG flow. The dilaton is naturally light whenever i)
confinement is reached fast enough (such as via the condensation of O) and ii)
the beta function is small (walking) at the condensation scale. These
conditions are satisfied for a class of models with a bulk pseudo-Goldstone
boson whose potential is nearly flat at small field and exponential at large
field values. Thus, the recent observation by Contino, Pomarol and Rattazzi
holds in CFTs with a single nearly-marginal operator. We also discuss the
holographic method to compute the condensate <O>, based on solving the
first-order nonlinear differential equation that the beta function satisfies.


title: Near-Infrared Evidence for a Sudden Temperature Increase in Eta Carinae

abstract:
  Aims. Eta Car's ultra-violet, optical, and X-ray light curves and its
spectrum suggest a physical change in its stellar wind over the last decade. It
was proposed that the mass-loss rate decreased by a factor of about 2 in the
last 15 years. We complement these recent results by investigating the past
evolution and the current state of eta Car in the near-infrared (IR). Methods.
We present JHKL photometry of eta Car obtained at SAAO Sutherland from
2004-2013 with the Mk II photometer at the 0.75-m telescope and JHKs photometry
with SIRIUS at the 1.4-m IRSF telescope from 2012-2013. The near-IR light
curves since 1972 are analyzed. Results. The long-term brightening trends in
eta Car's JHKL light curves were discontinuous around the 1998 periastron
passage. After 1998, the star shows excess emission above the extrapolated
trend from earlier dates, foremost in J and H, and the blueward, cyclical
progression in its near-IR colors is accelerated. The near-IR color evolution
is strongly correlated with the periastron passages. After correcting for the
secular trend we find that the color evolution matches an apparent increase in
blackbody temperature of an optically thick near-IR emitting plasma component
from about 3500 to 6000 K over the last 20 years. Conclusions. We suggest that
the changing near-IR emission may be caused by variability in optically thick
bremsstrahlung emission. Periastron passages play a key role in the observed
excess near-IR emission after 1998 and the long-term color evolution. We thus
propose as a hypothesis that angular momentum transfer (via tidal acceleration)
during periastron passages leads to sudden changes in eta Car's atmosphere
resulting in a long-term decrease in the mass-loss rate.


title: On the X-ray variability of magnetar 1RXS J170849.0-400910

abstract:
  We present a long-term X-ray flux and spectral analysis for 1RXS
J170849.0-400910 using Swift/XRT spanning over 8 years from 2005-2013. We also
analyze two observations from Chandra and XMM in the period from 2003-2004. In
this 10-yr period, 1RXS J170849.0-400910 displayed several rotational glitches.
Previous studies have claimed variations in the X-ray emission associated with
some of the glitches. From our analysis we find no evidence for significant
X-ray flux variations and evidence for only low-level spectral variations. We
also present an updated timing solution for 1RXS J170849.0-400910, from RXTE
and Swift observations, which includes a previously unreported glitch at MJD
56019. We discuss the frequency and implications of radiatively quiet glitches
in magnetars.


title: Topological cyclic homology via the norm

abstract:
  We describe a construction of the cyclotomic structure on topological
Hochschild homology ($THH$) of a ring spectrum using the Hill-Hopkins-Ravenel
multiplicative norm. Our analysis takes place entirely in the category of
equivariant orthogonal spectra, avoiding use of the B\"okstedt coherence
machinery. We are able to define versions of topological cyclic homology ($TC$)
and TR-theory relative to a cyclotomic commutative ring spectrum $A$. We
describe spectral sequences computing this relative theory $_ATR$ in terms of
$TR$ over the sphere spectrum and vice versa. Furthermore, our construction
permits a straightforward definition of the Adams operations on $TR$ and $TC$.


title:
On the Coverage Bound Problem of Empirical Likelihood Methods For Time
  Series

abstract:
  The upper bounds on the coverage probabilities of the confidence regions
based on blockwise empirical likelihood [Kitamura (1997)] and nonstandard
expansive empirical likelihood [Nordman et al. (2013)] methods for time series
data are investigated via studying the probability for the violation of the
convex hull constraint. The large sample bounds are derived on the basis of the
pivotal limit of the blockwise empirical log-likelihood ratio obtained under
the fixed-b asymptotics, which has been recently shown to provide a more
accurate approximation to the finite sample distribution than the conventional
chi-square approximation. Our theoretical and numerical findings suggest that
both the finite sample and large sample upper bounds for coverage probabilities
are strictly less than one and the blockwise empirical likelihood confidence
region can exhibit serious undercoverage when (i) the dimension of moment
conditions is moderate or large; (ii) the time series dependence is positively
strong; or (iii) the block size is large relative to sample size. A similar
finite sample coverage problem occurs for the nonstandard expansive empirical
likelihood. To alleviate the coverage bound problem, we propose to penalize
both empirical likelihood methods by relaxing the convex hull constraint.
Numerical simulations and data illustration demonstrate the effectiveness of
our proposed remedies in terms of delivering confidence sets with more accurate
coverage.


title: Renormalization: an advanced overview

abstract:
  We present several approaches to renormalization in QFT: the multi-scale
analysis in perturbative renormalization, the functional methods \`a la
Wetterich equation, and the loop-vertex expansion in non-perturbative
renormalization. While each of these is quite well-established, they go beyond
standard QFT textbook material, and may be little-known to specialists of each
other approach. This review is aimed at bridging this gap.


title: Stability Analysis and Design of a Network of Event-based Systems

abstract:
  We consider a network of event-based systems that use a shared wireless
medium to communicate with their respective controllers. These systems use a
contention resolution mechanism to arbitrate access to the shared network. We
identify sufficient conditions for Lyapunov mean square stability of each
control system in the network, and design event-based policies that guarantee
it. Our stability analysis is based on a Markov model that removes the
network-induced correlation between the states of the control systems in the
network. Analyzing the stability of this Markov model remains a challenge, as
the event-triggering policy renders the estimation error non-Gaussian. Hence,
we identify an auxiliary system that furnishes an upper bound for the variance
of the system states. Using the stability analysis, we design policies, such as
the constant-probability policy, for adapting the event-triggering thresholds
to the delay in accessing the network. Realistic wireless networked control
examples illustrate the applicability of the presented approach.


title:
Hydrodynamical simulations of coupled and uncoupled quintessence models
  I: Halo properties and the cosmic web

abstract:
  We present the results of a series of adiabatic hydrodynamical simulations of
several quintessence models (both with a free and an interacting scalar field)
in comparison to a standard \LCDM\ cosmology. For each we use $2\times1024^3$
particles in a $250$\hMpc\ periodic box assuming WMAP7 cosmology. In this work
we focus on the properties of haloes in the cosmic web at $z=0$. The web is
classified into \emph{voids}, \emph{sheets}, \emph{filaments} and \emph{knots}
depending on the eigenvalues of the velocity shear tensor, which are an
excellent proxy for the underlying overdensity distribution. We find that the
properties of objects classified according to their surrounding environment
shows a substantial dependence on the underlying cosmology; for example, while
$V_{\rm max}$ shows average deviations of $\approx5$ per cent across the
different models when considering the full halo sample, comparing objects
classified according to their environment, the size of the deviation can be as
large as $20$ per cent.
  We also find that halo spin parameters are positively correlated to the
coupling, whereas halo concentrations show the opposite behaviour. Furthermore,
when studying the concentration-mass relation in different environments, we
find that in all cosmologies underdense regions have a larger normalization and
a shallower slope. While this behaviour is found to characterize all the
models, differences in the best-fit relations are enhanced in (coupled) dark
energy, thus providing a clearer prediction for this class of models.


title: Effects of AMM on the EoS of Magnetized Dense Systems

abstract:
  We investigate the effects of the anomalous magnetic moment (AMM) in the EoS
of a fermion system in the presence of a magnetic field. In the region of
strong magnetic fields ($B>m^2$) the AMM is found from the one-loop fermion
self-energy. In contrast to the weak-field AMM found by Schwinger, in the
strong magnetic field case, the AMM depends on the Landau level (LL) and
decreases with it. The effects of the AMM in the EoS at intermediate-to-large
fields can be found introducing the one-loop, LL-dependent AMM in the effective
Lagrangian that is then used to find the thermodynamic potential of the system.
We compare the plots of the parallel and perpendicular pressures versus the
magnetic field in the strong field region considering the LL-dependent AMM, the
Schwinger AMM, and no AMM at all. The results clearly show a separation between
the physical magnitudes found using the Schwinger AMM and the LL-dependent AMM.
This is an indication of the inconsistency of considering the Schwinger AMM
beyond the weak field region $B< m^2$ where it was originally found. The curves
for the EoS, pressures and magnetization at different fields give rise to the
well-known de Haas van Alphen oscillations, associated to the change in the
number of LL contributing at different fields.


title: Atomic Configuration of Nitrogen Doped Single-Walled Carbon Nanotubes

abstract:
  Having access to the chemical environment at the atomic level of a dopant in
a nanostructure is crucial for the understanding of its properties. We have
performed atomically-resolved electron energy-loss spectroscopy to detect
individual nitrogen dopants in single-walled carbon nanotubes and compared with
first principles calculations. We demonstrate that nitrogen doping occurs as
single atoms in different bonding configurations: graphitic-like and
pyrrolic-like substitutional nitrogen neighbouring local lattice distortion
such as Stone-Thrower-Wales defects. The stability under the electron beam of
these nanotubes has been studied in two extreme cases of nitrogen incorporation
content and configuration. These findings provide key information for the
applications of these nanostructures.


title: Albanese varieties of abelian covers

abstract:
  We show that Albanese varieties of abelian covers of projective plane are
isogenous to product of isogeny components of abelian varieties associated with
singularities of the ramification locus. In particular Albanese varieties of
abelian covers of projective plane ramified over arrangements of lines and
uniformized by unit ball are isogenous to a product of Jacobians of Fermat
curves. Periodicity of the sequence of (semi-abelian) Albanese varieties of
unramified cyclic covers of complements to a plane singular curve is shown.


title:
Momentum dependence of spin-orbit interaction effects in single-layer
  and multi-layer transition metal dichalcogenides

abstract:
  One of the main characteristics of the new family of two-dimensional crystals
of semiconducting transition metal dichalcogenides (TMD) is the strong
spin-orbit interaction, which makes them very promising for future applications
in spintronics and valleytronics devices. Here we present a detailed study of
the effect of spin-orbit coupling (SOC) on the band structure of single-layer
and bulk TMDs, including explicitly the role of the chalcogen orbitals and
their hybridization with the transition metal atoms. To this aim, we combine
density functional theory (DFT) calculations with a Slater-Koster tight-binding
model. Whereas most of the previous tight-binding models have been restricted
to the K and K' points of the Brillouin zone (BZ), here we consider the effect
of SOC in the whole BZ, and the results are compared to the band structure
obtained by DFT methods. The tight-binding model is used to analyze the effect
of SOC in the band structure, considering separately the contributions from the
transition metal and the chalcogen atoms. Finally, we present a scenario where,
in the case of strong SOC, the spin/orbital/valley entanglement at the minimum
of the conduction band at Q can be probed and be of experimental interest in
the most common cases of electron-doping reported for this family of compounds.


title:
A Hardy inequality on Riemannian manifolds and classification of
  discrete Dirichlet spectra

abstract:
  We prove a Hardy inequality for uniformly elliptic operators subject to
Dirichlet or mixed boundary conditions on domains $\Omega$ with piecewiese
smooth boundary in arbitrary Riemannian Manifolds (M, g). Employing an approach
of E.B. Davies for the euclidean case, we show that it implies a sufficient
geometric criterion under which the Laplace- Beltrami operator with Dirichlet
boundary conditions $\Delta^D$ has purely discrete spectrum on $\Omega$. We
proceed to classify all non-compact $\Omega$ with discrete spectrum up to a
boundary regularity condition and show that these include for example polygons
with ideal vertices in manifolds of negative curvature. This a new result for
non-constant curvature.


title:
Reliable and efficient a posteriori error estimates of DG methods for a
  frictional contact problem

abstract:
  A posteriori error estimators are studied for discontinuous Galerkin methods
for solving a frictional contact problem, which is a representative elliptic
variational inequality of the second kind. The estimators are derived by
relating the error of the variational inequality to that of a linear problem.
Reliability and efficiency of the estimators are shown.


title: Time-Correlation and Decoherence in a Two-Particle Interferometer

abstract:
  A two-particle interferometer is theoretically analyzed, to show how
decoherence induced by interactions with the environment affects time
correlations, a process we call time-correlation de-coherence. Specifically, on
the basis of simple mathematical analysis we show how the interaction between a
bipartite entangled system and a photon bath representing the environment can
efface the oscillations in the coincidence-detection rate of the
interferometer. We discuss the dependence of this kind of decoherence on the
photon energy and density.


title: Asteroid 2013 ND15: Trojan companion to Venus, PHA to the Earth

abstract:
  Venus has three known co-orbitals: (322756) 2001 CK32, 2002 VE68 and 2012
XE133. The first two have absolute magnitudes 18 < H < 21. The third one,
significantly smaller at H = 23.4 mag, is a recent discovery that signals the
probable presence of many other similar objects: small transient companions to
Venus that are also potentially hazardous asteroids (PHAs). Here, we study the
dynamical evolution of the recently discovered asteroid 2013 ND15. At H = 24.1
mag, this minor body is yet another small Venus co-orbital and PHA, currently
close to the Lagrangian point L4 and following the most eccentric path found so
far for objects in this group. Due to its high eccentricity (0.6), its dynamics
is different from that of the other three known Venus co-orbitals even if they
all are near-Earth objects (NEOs). A Monte Carlo simulation that uses the
orbital data and discovery circumstances of the four objects as proxies to
estimate the current size of this population, indicates that the number of
high-eccentricity, low-inclination Venus co-orbital NEOs may have been greatly
underestimated by current models. Three out of four known objects were
discovered with solar elongation at perigee greater than 135 degrees even if
visibility estimates show that less than 4 per cent of these objects are
expected to reach perigee at such large elongations. Nearly 70 per cent of the
objects discussed here have elongation at perigee < 90 degrees and 65 per cent
are prospective PHAs.


title: Light spanners for snowflake metrics

abstract:
  A classic result in the study of spanners is the existence of light
low-stretch spanners for Euclidean spaces. These spanners ahve arbitrary low
stretch, and weight only a constant factor greater than that of the minimum
spanning tree of the points (with dependence on the stretch and Euclidean
dimention). A central open problem in this field asks whether other spaces
admit low weight spanners as well - for example metric space with low intrinsic
dimension - yet only a handful of results of this type are known.
  In this paper, we consider snowflake metric spaces of low intrinsic
dimension. The {\alpha}-snowflake of a metric (X,{\delta}) is the metric
(X,${\delta}^{\alpha}$) for 0<{\alpha}<1. By utilizing an approach completely
different than those used for Euclidean spaces, we demonstrate that snowflake
metrics admit light spanners. Further, we show that the spanner is of diameter
O($\log$n), a result not possible for Euclidean spaces. As an immediate
corollary to our spanner, we obtain dramatic improvments in algorithms for the
traveling salesman problem in this setting, achieving a polynomial-time
approximation scheme with near-linear runtime. Along the way, we show that all
${\ell}_p$ spaces admit light spanners, a result of interest in its own right.


title:
Model selection of stochastic simulation algorithm based on generalized
  divergence measures

abstract:
  MCMC methods (Monte Carlo Markov Chain) are a class of methods used to
perform simulations per a probability distribution $P$. These methods are often
used when we have difficulties to directly sample per a given probability
distribution $P$ . This distribution is then considered as a target and
generates a Markov chain $(X_n)_{n\in\mathbb{N}}$ that, when $n$ is large we
have $X_n\sim P$. These MCMC methods consist of several simulation strategies
including the \emph{Independent Sampler (IS)}, the \emph{Random Walk of
Metropolis Hastings \small{(RWMH)}}, the \emph{Gibbs sampler}, the
\emph{Adaptive Metropolis (AM)} and \emph{Metropolis Within Gibbs (MWG)}
strategy. Each of these strategies can generate a Markov chain and is
associated with a convergence speed. It is interesting, with a given target
law, to compare several simulation strategies for determining the best.
Chauveau and Vandekerkhove \cite{Chauv2007} have compared IS and RWMH
strategies using the Kullback-Leibler divergence measure. In our article we
will compare our five simulation methods already mentioned using generalized
divergence measures. These divergence measures are taken in family of
$\alpha$-divergence measures \cite{Cichocki2010}, with a parameter $\alpha$.
This is the R\'enyi divergence, Tsallis divergence and $D_\alpha$ divergence .


title: Decoherence control by quantum decoherence itself

abstract:
  We propose a general approach of protecting a two-level system against
decoherence via quantum engineering of non-classical multiple superpositions of
coherent states in a non-Markovian reservoir. The scheme surprisingly only uses
the system-environment interaction responsible for the decoherence and
projective measurements of the two-level system. We demonstrate the method on
the example of an excitonic qubit in self-assembled semiconductor quantum dots
coupled to super-Ohmic reservoir of acoustic phonons.


title: Semicontinuity of eigenvalues under intrinsic flat convergence

abstract:
  We use the theory of rectifiable metric spaces to define a Dirichlet energy
of Lipschitz functions defined on the support of integral currents. This energy
is obtained by integration of the square of the norm of the tangential
derivative, or equivalently of the approximate local dilatation, of the
Lipschitz functions. We define min-max values based on the normalized energy
and show that when integral current spaces converge in the intrinsic flat sense
without loss of volume, the min-max values of the limit space are larger than
or equal to the upper limit of the min-max values of the currents in the
sequence. In particular, the infimum of the normalized energy is
semicontinuous. On spaces that are infinitesimally Hilbertian, we can define a
linear Laplace operator. We can show that semicontinuity under intrinsic flat
convergence holds for eigenvalues below the essential spectrum, if the total
volume of the spaces converges as well.


title:
Higher order commutator estimates and local existence for the
  non-resistive MHD equations and related models

abstract:
  This paper establishes the local-in-time existence and uniqueness of strong
solutions in $H^{s}$ for $s > n/2$ to the viscous, non-resistive
magnetohydrodynamics (MHD) equations in $\mathbb{R}^{n}$, $n=2, 3$, as well as
for a related model where the advection terms are removed from the velocity
equation. The uniform bounds required for proving existence are established by
means of a new estimate, which is a partial generalisation of the commutator
estimate of Kato & Ponce (Comm. Pure Appl. Math. 41(7), 891-907, 1988).


title:
The effect of isotopic splitting on the bisector and inversions of the
  solar Ca II 854.2 nm line

abstract:
  The Ca II 854.2 nm spectral line is a common diagnostic of the solar
chromosphere. The average line profile shows an asymmetric core, and its
bisector shows a characteristic inverse-C shape. The line actually consists of
six components with slightly different wavelengths depending on the isotope of
calcium. This isotopic splitting of the line has been taken into account in
studies of non-solar stars, but never for the Sun. We performed non-LTE
radiative transfer computations from three models of the solar atmosphere and
show that the asymmetric line-core and inverse C-shape of the bisector of the
854.2 nm line can be explained by isotopic splitting. We confirm this finding
by analysing observations and showing that the line asymmetry is present
irrespective of conditions in the solar atmosphere. Finally, we show that
inversions based on the Ca II 854.2 nm line should take the isotopic splitting
into account, otherwise the inferred atmospheres will contain erroneous
velocity gradients and temperatures.


title: Dark decay of the top quark

abstract:
  We suggest top quark decays as a venue to search for light dark force
carriers. The top quark is the heaviest particle in the standard model whose
decays are relatively poorly measured, allowing sufficient room for exotic
decay modes from new physics. A very light (GeV scale) dark gauge boson (Z') is
a recently highlighted hypothetical particle that can address some
astrophysical anomalies as well as the 3.6 sigma deviation in the muon g-2
measurement. We present and study a possible scenario that top quark decays as
t -> b W + Z's. This is the same as the dominant top quark decay (t -> b W)
accompanied by one or multiple dark force carriers. The Z' can be easily
boosted, and it can decay into highly collimated leptons (lepton-jet) with
large branching ratio. We discuss the implications for the Large Hadron
Collider experiments including the analysis based on the lepton-jets.


title:
Metapopulation epidemic models with heterogeneous mixing and travel
  behaviour

abstract:
  The complex interplay between population movements in space and
non-homogeneous mixing patterns have so far hindered the fundamental
understanding of the conditions for spatial invasion through a general
theoretical framework. To address this issue, we present an analytical
modelling approach taking into account such interplay under general conditions
of mobility and interactions, in the simplifying assumption of two population
classes. We describe a spatially structured population with non-homogeneous
mixing and travel behaviour through a multi-host stochastic epidemic
metapopulation model. Different population partitions, mixing patterns and
mobility structures are considered, along with a specific application for the
study of the role of age partition in the early spread of the 2009 H1N1
pandemic influenza.
  We provide a complete mathematical formulation of the model and derive a
semi-analytical expression of the threshold condition for global invasion of an
emerging infectious disease in the metapopulation system. A rich solution space
is found that depends on the social partition of the population, the pattern of
contacts across groups and their relative social activity, the travel attitude
of each class, and the topological and traffic features of the mobility
network. Reducing the activity of the less social group and reducing the
cross-group mixing are predicted to be the most efficient strategies for
controlling the pandemic potential in the case the less active group
constitutes the majority of travellers. If instead traveling is dominated by
the more social class, our model predicts the existence of an optimal
across-groups mixing that maximises the pandemic potential of the disease,
whereas the impact of variations in the activity of each group is less
important.


title:
Existence results for optimal control problems with some special
  non-linear dependence on state and control

abstract:
  We present a general approach to prove existence of solutions for optimal
control problems not based on typical convexity conditions which quite often
are very hard, if not impossible, to check. By taking advantage of several
relaxations of the problem, we isolate an assumption which guarantees the
existence of solutions of the original optimal control problem. To show the
validity of this crucial hypothesis through various means and in various
contexts is the main body of this contribution. In each such situation, we end
up with some existence result. In particular, we would like to stress a general
result that takes advantage of the particular structure of both the cost
functional and the state equation. One main motivation for our work here comes
from a model for guidance and control of ocean vehicles. Some explicit
existence results and comparison examples are given.


title: Algebraic invariants of truncated Fourier matrices

abstract:
  A partial Hadamard matrix $H\in M_{M\times N}(\mathbb C)$ is called of
"classical type" if the associated quantum semigroup
$G\subset\widetilde{S}_M^+$ is classical. In combinatorial terms, if
$H_1,\ldots,H_M\in\mathbb T^N$ are the rows of the matrix, the vectors
$H_i/H_j\in\mathbb T^N$ must be pairwise proportional, or orthogonal. We
propose here of definition for the algebraic (or quantum) invariants of such
matrices. For the truncated Fourier matrices, which are all of classical type,
we obtain certain Bernoulli laws, that we compute in the $N>>M$ regime.


title:
Beyond Reuse Distance Analysis: Dynamic Analysis for Characterization of
  Data Locality Potential

abstract:
  Emerging computer architectures will feature drastically decreased flops/byte
(ratio of peak processing rate to memory bandwidth) as highlighted by recent
studies on Exascale architectural trends. Further, flops are getting cheaper
while the energy cost of data movement is increasingly dominant. The
understanding and characterization of data locality properties of computations
is critical in order to guide efforts to enhance data locality. Reuse distance
analysis of memory address traces is a valuable tool to perform data locality
characterization of programs. A single reuse distance analysis can be used to
estimate the number of cache misses in a fully associative LRU cache of any
size, thereby providing estimates on the minimum bandwidth requirements at
different levels of the memory hierarchy to avoid being bandwidth bound.
However, such an analysis only holds for the particular execution order that
produced the trace. It cannot estimate potential improvement in data locality
through dependence preserving transformations that change the execution
schedule of the operations in the computation. In this article, we develop a
novel dynamic analysis approach to characterize the inherent locality
properties of a computation and thereby assess the potential for data locality
enhancement via dependence preserving transformations. The execution trace of a
code is analyzed to extract a computational directed acyclic graph (CDAG) of
the data dependences. The CDAG is then partitioned into convex subsets, and the
convex partitioning is used to reorder the operations in the execution trace to
enhance data locality. The approach enables us to go beyond reuse distance
analysis of a single specific order of execution of the operations of a
computation in characterization of its data locality properties. It can serve a
valuable role in identifying promising code regions for manual transformation,
as well as assessing the effectiveness of compiler transformations for data
locality enhancement. We demonstrate the effectiveness of the approach using a
number of benchmarks, including case studies where the potential shown by the
analysis is exploited to achieve lower data movement costs and better
performance.


title:
Identified Particle Production in p-Pb Collisions Measured with the
  ALICE Detector

abstract:
  ALICE has unique capabilities among the LHC experiments for particle
identification (PID) at mid-rapidity ($|\eta| < 0.9$) over a wide range of
transverse momentum ($p_{\rm T}$). In this proceeding recent measurements of
$p_{\rm T}$ spectra for $\pi$, K, ${\rm K}^0_s$, p, and $\Lambda$ in p-Pb
collisions are presented and compared to results from Pb-Pb and pp. In
particular the implications for the question of the existence of radial flow in
small systems is discussed.


title: Mean-field dynamo action from delayed transport

abstract:
  We analyze the nature of dynamo action that produces horizontally averaged
magnetic fields in two particular flows that were studied by Roberts (1972,
Phil. Trans. R. Soc. A 271, 411), namely his flows II and III. They have zero
kinetic helicity either pointwise (flow II), or on average (flow III). Using
direct numerical simulations, we determine the onset conditions for dynamo
action at moderate values of the magnetic Reynolds number. Using the test-field
method, we show that the turbulent magnetic diffusivity is then positive for
both flows. However, we demonstrate that for both flows large-scale dynamo
action occurs through delayed transport. Mathematically speaking, the magnetic
field at earlier times contributes to the electromotive force through the
off-diagonal components of the alpha tensor such that a zero mean magnetic
field becomes unstable to dynamo action. This represents a qualitatively new
mean-field dynamo mechanism not previously described.


title: Tie Strength Distribution in Scientific Collaboration Networks

abstract:
  Science is increasingly dominated by teams. Understanding patterns of
scientific collaboration and their impacts on the productivity and evolution of
disciplines is crucial to understand scientific processes. Electronic
bibliography offers a unique opportunity to map and investigate the nature of
scientific collaboration. Recent work have demonstrated a counter-intuitive
organizational pattern of scientific collaboration networks: densely
interconnected local clusters consist of weak ties, whereas strong ties play
the role of connecting different clusters. This pattern contrasts itself from
many other types of networks where strong ties form communities while weak ties
connect different communities. Although there are many models for collaboration
networks, no model reproduces this pattern. In this paper, we present an
evolution model of collaboration networks, which reproduces many properties of
real-world collaboration networks, including the organization of tie strengths,
skewed degree and weight distribution, high clustering and assortative mixing.


title: Orbit closures and rational surfaces

abstract:
  In this paper we study the Grassmannian of submodules of a given dimension
inside a finitely generated projective module $P$ for a finite dimensional
algebra $\Lambda$ over an algebraically closed field. The orbit of such a
submodule $C$ under the action of $\mathrm{Aut}_\Lambda ( P )$ on the
Grassmannian encodes information on the degenerations of $P/C$ and has been
considered by a number of authors. The goal of this article is to bound the
geometry of two-dimensional orbit closures in terms of representation-theoretic
data. Several examples are given to illustrate the interplay between the
geometry of the projective surfaces which arise and the corresponding posets of
degenerations.


title: Quark-hadron phase transition in DGP including BD brane

abstract:
  A DGP brane-world model with a perfect fluid brane matter including a
Brans-Dicke (BD) scalar field on brane has been utilized to investigate the
problem of the quark-hadron phase (QHP) transition in early times of the
Universe evolution. The presence of the BD scalar field comes up with some
modification terms in the Friedmann equation. Since the behavior of phase
transition strongly depends on the basic evolution equations, even a small
change in these relations might come to interesting results about the time of
transition. The phase transition is investigated using two scenarios of the
first-order phase transition and smooth crossover phase transition. For
first-order scenario, which is used for intermediate temperature regime, the
evolution of the physical quantities, such as temperature and scale factor, are
investigated before, during and after the phase transition. The results show
that the transition occurs in about micro-second. In the next part, the
phenomenon is studied by assuming a smooth crossover transition where the
lattice QCD data is utilized to obtain a realistic equation of state for the
matter. The investigation for this part is performed in two regimes of high and
low-temperature. Using trace anomaly in the high-temperature regime specifies a
simple equation of state which states that the quark-gluon behaves like
radiation. However, in the low-temperature regime, the trace anomaly is
affected by discretization effects, and the hadron resonance gas model is
utilized instead. Using this model, a more realistic equation of state could be
found in the low-temperature regime. The crossover phase transition in both
regimes is considered. The results determine that the transition occurs at the
time around a few micro-second. Also, it is realized that the transition in the
low-temperature regime occurs after the transition in the high-temperature
regime.


title:
Shape coexistence in neutron-deficient Hg isotopes studied via lifetime
  measurements in $^{184,186}$Hg and two-state mixing calculations

abstract:
  The neutron-deficient mercury isotopes, $^{184,186}$Hg, were studied with the
Recoil Distance Doppler Shift (RDDS) method using the Gammasphere array and the
K\"oln Plunger device. The Differential Decay Curve Method (DDCM) was employed
to determine the lifetimes of the yrast states in $^{184,186}$Hg. An
improvement on previously measured values of yrast states up to $8^{+}$ is
presented as well as first values for the $9_{3}$ state in $^{184}$Hg and
$10^{+}$ state in $^{186}$Hg. $B(E2)$ values are calculated and compared to a
two-state mixing model which utilizes the variable moment of inertia (VMI)
model, allowing for extraction of spin-dependent mixing strengths and
amplitudes.


title:
A Scalable Conditional Independence Test for Nonlinear, Non-Gaussian
  Data

abstract:
  Many relations of scientific interest are nonlinear, and even in linear
systems distributions are often non-Gaussian, for example in fMRI BOLD data. A
class of search procedures for causal relations in high dimensional data relies
on sample derived conditional independence decisions. The most common
applications rely on Gaussian tests that can be systematically erroneous in
nonlinear non-Gaussian cases. Recent work (Gretton et al. (2009), Tillman et
al. (2009), Zhang et al. (2011)) has proposed conditional independence tests
using Reproducing Kernel Hilbert Spaces (RKHS). Among these, perhaps the most
efficient has been KCI (Kernel Conditional Independence, Zhang et al. (2011)),
with computational requirements that grow effectively at least as O(N3),
placing it out of range of large sample size analysis, and restricting its
applicability to high dimensional data sets. We propose a class of O(N2) tests
using conditional correlation independence (CCI) that require a few seconds on
a standard workstation for tests that require tens of minutes to hours for the
KCI method, depending on degree of parallelization, with similar accuracy. For
accuracy on difficult nonlinear, non-Gaussian data sets, we also compare a
recent test due to Harris & Drton (2012), applicable to nonlinear, non-Gaussian
distributions in the Gaussian copula, as well as to partial correlation, a
linear Gaussian test.


title: Subtle flickering in Cepheids

abstract:
  Fundamental mode classical Cepheids have light curves which repeat accurately
enough that we can watch them evolve (change period). The new level of accuracy
and quantity of data with the {\it Kepler} and {\it MOST} satellites probes
this further. An intriguing result was found in the long time-series of Kepler
data for V1154 Cyg the one classical Cepheid (fundamental mode, P = 4.9$^d$) in
the field, which has short term changes in period ($\simeq$20 minutes),
correlated for $\simeq$10 cycles (period jitter). To follow this up, we
obtained a month long series of observations of the fundamental mode Cepheid RT
Aur and the first overtone pulsator SZ Tau. RT Aur shows the traditional strict
repetition of the light curve, with the Fourier amplitude ratio $R_1/R_2$
remaining nearly constant.
  The light curve of SZ Tau, on the other hand, fluctuates in amplitude ratio
at the level of approximately $50\%$. Furthermore prewhitening the RT Aur data
with 10 frequencies reduces the Fourier spectrum to noise. For SZ Tau,
considerable power is left after this prewhitening in a complicated variety of
frequencies.


title: 1D Cahn-Hilliard dynamics : coarsening and interrupted coarsening

abstract:
  Many systems exhibit a phase where the order parameter is spatially
modulated. These patterns can be the result of a frustration caused by the
competition between interaction forces with opposite effects. In all models
with local interactions, these ordered phases disappear in the strong
segregation regime (low temperature). It is expected however that these phases
should persist in the case of long range interactions, which can't be correctly
described by a Ginzburg-Landau type model with only a finite number of spatial
derivatives of the order parameter. An alternative approach is to study the
dynamics of the phase transition or pattern formation. While, in the usual
process of Ostwald ripening, succession of doubling of the domain size leads to
a total segregation, or macro-segregation, C. Misbah and P. Politi have shown
that long-range interactions could cause an interruption of this coalescence
process, stabilizing a pattern which then remains in a micro-structured state
or super-crystal. We show that this is the case for a modified Cahn-Hilliard
dynamics due to Oono which includes a non local term and which is particularly
well suited to describe systems with a modulated phase.


title:
A regularization approach to functional It\^o calculus and
  strong-viscosity solutions to path-dependent PDEs

abstract:
  First, we revisit functional It\^o/path-dependent calculus started by B.
Dupire, R. Cont and D.-A. Fourni\'e, using the formulation of calculus via
regularization. Relations with the corresponding Banach space valued calculus
introduced by C. Di Girolami and the second named author are explored. The
second part of the paper is devoted to the study of the Kolmogorov type
equation associated with the so called window Brownian motion, called
path-dependent heat equation, for which well-posedness at the level of
classical solutions is established. Then, a notion of strong approximating
solution, called strong-viscosity solution, is introduced which is supposed to
be a substitution tool to the viscosity solution. For that kind of solution, we
also prove existence and uniqueness. The notion of strong-viscosity solution
motivates the last part of the paper which is devoted to explore this new
concept of solution for general semilinear PDEs in the finite dimensional case.
We prove an equivalence result between the classical viscosity solution and the
new one. The definition of strong-viscosity solution for semilinear PDEs is
inspired by the notion of "good" solution, and it is based again on an
approximating procedure.


title:
MPAgenomics : An R package for multi-patients analysis of genomic
  markers

abstract:
  MPAgenomics, standing for multi-patients analysis (MPA) of genomic markers,
is an R-package devoted to: (i) efficient segmentation, and (ii) genomic marker
selection from multi-patient copy number and SNP data profiles. It provides
wrappers from commonly used packages to facilitate their repeated (sometimes
difficult) use, offering an easy-to-use pipeline for beginners in R. The
segmentation of successive multiple profiles (finding losses and gains) is
based on a new automatic choice of influential parameters since default ones
were misleading in the original packages. Considering multiple profiles in the
same time, MPAgenomics wraps efficient penalized regression methods to select
relevant markers associated with a given response.


title: Residual Z2 x Z2 symmetries and lepton mixing

abstract:
  We consider two novel scenarios of residual symmetries of the lepton mass
matrices. Firstly we assume a Z2 x Z2 symmetry G_ell for the charged-lepton
mass matrix and a Z2 symmetry G_nu for the light neutrino mass matrix. With
this setting, the moduli of the elements of one column of the lepton mixing
matrix are fixed up to a reordering. One may interchange the roles of G_ell and
G_nu in this scenario, thereby constraining a row, instead of a column, of the
mixing matrix. Secondly we assume a residual symmetry group G_ell \cong Zm
(m>2) which is generated by a matrix with a doubly-degenerate eigenvalue. Then,
with G_nu \cong Z2 x Z2 the moduli of the elements of a row of the lepton
mixing matrix get fixed. Using the library of small groups we have performed a
search for groups which may embed G_ell and G_nu in each of these two
scenarios. We have found only two phenomenologically viable possibilities, one
of them constraining a column and the other one a row of the mixing matrix.


title: Achieving SK Capacity in the Source Model: When Must All Terminals Talk?

abstract:
  In this paper, we address the problem of characterizing the instances of the
multiterminal source model of Csisz\'ar and Narayan in which communication from
all terminals is needed for establishing a secret key of maximum rate. We give
an information-theoretic sufficient condition for identifying such instances.
We believe that our sufficient condition is in fact an exact characterization,
but we are only able to prove this in the case of the three-terminal source
model. We also give a relatively simple criterion for determining whether or
not our condition holds for a given multiterminal source model.


title:
Failure of Breit-Wigner and success of dispersive descriptions of the
  \tau^-\to K^-\eta\nu_\tau decays

abstract:
  The \tau^-\to K^-\eta\nu_\tau decays have been studied using Chiral
Perturbation Theory extended by including resonances as active fields. We have
found that the treatment of final state interactions is crucial to provide a
good description of the data. The Breit-Wigner approximation does not resum
them and neglects the real part of the corresponding chiral loop functions,
which violates analyticity and leads to a failure in the confrontation with the
data. On the contrary, its resummation by means of an Omn\`es-like
exponentiation of through a dispersive representation provides a successful
explanation of the measurements. These results illustrate the fact that
Breit-Wigner parametrizations of hadronic data, although simple and easy to
handle, lack a link with the underlying strong interaction theory and should be
avoided.
  As a result of our analysis we determine the properties of the K*(1410)
resonance with a precision competitive to its traditional extraction using
\tau^-\to (K\pi)^-\nu_\tau decays, albeit the much limited statistics
accumulated for the \tau^-\to K^-\eta\nu_\tau channel. We also predict the soon
discovery of the \tau^-\to K^-\eta'\nu_\tau decays.


title: Experimental Design for Human-in-the-Loop Driving Simulations

abstract:
  This report describes a new experimental setup for human-in-the-loop
simulations. A force feedback simulator with four axis motion has been setup
for real-time driving experiments. The simulator will move to simulate the
forces a driver feels while driving, which allows for a realistic experience
for the driver. This setup allows for flexibility and control for the
researcher in a realistic simulation environment. Experiments concerning driver
distraction can also be carried out safely in this test bed, in addition to
multi-agent experiments. All necessary code to run the simulator, the
additional sensors, and the basic processing is available for use.


title: Smooth approximations of the Conical Kahler-Ricci flows

abstract:
  In this note, we show that the conical K\"ahler-Ricci flows introduced in
\cite{CYW} exist for all time $t\in [0,\infty)$ in the weak sense. As a key
ingredient of the proof, we show that a conical K\"ahler-Ricci flow is actually
the limit of a sequence of smooth K\"ahler-Ricci flows.


title: Evidence for the 125 GeV Higgs boson decaying to a pair of tau leptons

abstract:
  A search for a standard model Higgs boson decaying into a pair of tau leptons
is performed using events recorded by the CMS experiment at the LHC in 2011 and
2012. The dataset corresponds to an integrated luminosity of 4.9 inverse
femtobarns at a centre-of-mass energy of 7 TeV and 19.7 inverse femtobarns at 8
TeV. Each tau lepton decays hadronically or leptonically to an electron or a
muon, leading to six different final states for the tau-lepton pair, all
considered in this analysis. An excess of events is observed over the expected
background contributions, with a local significance larger than 3 standard
deviations for m[H] values between 115 and 130 GeV. The best fit of the
observed H to tau tau signal cross section for m[H] = 125 GeV is 0.78 +- 0.27
times the standard model expectation. These observations constitute evidence
for the 125 GeV Higgs boson decaying to a pair of tau leptons.


title: Invariants of Hamiltonian flow on locally complete intersections

abstract:
  We consider the Hamiltonian flow on complex complete intersection surfaces
with isolated singularities, equipped with the Jacobian Poisson structure. More
generally we consider complete intersections of arbitrary dimension equipped
with Hamiltonian flow with respect to the natural top polyvector field, which
one should view as a degenerate Calabi-Yau structure.
  Our main result computes the coinvariants of functions under the Hamiltonian
flow. In the surface case this is the zeroth Poisson homology, and our result
generalizes those of Greuel, Alev and Lambre, and the authors in the
quasihomogeneous and formal cases. Its dimension is the sum of the dimension of
the top cohomology and the sum of the Milnor numbers of the singularities. In
other words, this equals the dimension of the top cohomology of a smoothing of
the variety.
  More generally, we compute the derived coinvariants, which replaces the top
cohomology by all of the cohomology. Still more generally we compute the
D-module which represents all invariants under Hamiltonian flow, which is a
nontrivial extension (on both sides) of the intersection cohomology D-module,
which is maximal on the bottom but not on the top. For cones over smooth curves
of genus g, the extension on the top is the holomorphic half of the maximal
extension.


title: Jet-quenching parameter $\hat{q}$ in the nonperturbative region

abstract:
  We investigate the jet-quenching parameter $\hat{q}$ for the quark-gluon
plasma (QGP) for $N_c=3$, defined nonperturbatively with the Wilson loop in the
light-cone (LC) coordinate, at finite temperature $(T)$. Considering the
effective static (heavy) quark-antiquark potential $V_{\bar{Q}Q}=\sigma
L+C-A/L$, where $L$ indicates the LC transverse separation between the quarks,
we obtain $\hat{q}\approx8V_{\bar{Q}Q}/L^2$. The $T$ dependences for $L$ and
other relevant parameters are extracted from the $T$-dependent instanton
(trivial-holonomy caloron) length parameters and the lattice QCD data. By
choosing $L\approx{a}\approx\bar{\rho}_T$, in which $a$ and $\bar{\rho}_T$
denote the lattice spacing and the $T$-dependent average (anti)instanton size,
respectively, we acquire numerically that $\hat{q}=(5\sim25)\,\mathrm{GeV/fm}$
for $T=(0\sim0.6)$ GeV, and these values are well consistent with other
estimations from AdS/CFT and experimental analyses. It turns out that $\hat{q}$
is produced almost by the Coulomb and constant potentials of $V_{\bar{Q}Q}$. We
also observe that the ratio $T^3/\hat{q}$ turns into being saturated to
$\sim4.45\times10^{-2}$ for $T\gtrsim0.4$ GeV, indicating the strongly-coupled
QGP, and $\hat{q}$ behaves proportionally to $T^3$ for high $T$.


title: Large Scale Cosmological Anomalies and Inhomogeneous Dark Energy

abstract:
  A wide range of large scale observations hint towards possible modifications
on the standard cosmological model which is based on a homogeneous and
isotropic universe with a small cosmological constant and matter. These
observations, also known as "cosmic anomalies" include unexpected Cosmic
Microwave Background perturbations on large angular scales, large dipolar
peculiar velocity flows of galaxies ("bulk flows"), the measurement of
inhomogenous values of the fine structure constant on cosmological scales
("alpha dipole") and other effects. The presence of the observational anomalies
could either be a large statistical fluctuation in the context of {\lcdm} or it
could indicate a non-trivial departure from the cosmological principle on
Hubble scales. Such a departure is very much constrained by cosmological
observations for matter. For dark energy however there are no significant
observational constraints for Hubble scale inhomogeneities. In this brief
review I discuss some of the theoretical models that can naturally lead to
inhomogeneous dark energy, their observational constraints and their potential
to explain the large scale cosmic anomalies.


title:
High-mobility transport anisotropy and linear dichroism in few-layer
  black phosphorus

abstract:
  Two-dimensional crystals are emerging materials for nanoelectronics.
Development of the field requires candidate systems with both a high carrier
mobility and, in contrast to graphene, a sufficiently large electronic bandgap.
Here we present a detailed theoretical investigation of the atomic and
electronic structure of few-layer black phosphorus (BP) in order to predict its
electrical and optical properties. This system has a direct bandgap, tunable
from 1.51 eV for a monolayer to 0.59 eV for a 5-layer sample. We predict that
the mobilities are hole-dominated, rather high and highly anisotropic. The
monolayer is exceptional in having an extremely high hole-mobility (of order
10000 cm$^{2}$ V$^{-1}$ s$^{-1}$) and anomalous elastic properties which
reverse the anisotropy. Light absorption spectra indicate linear dichroism
between perpendicular in-plane directions, which allows optical determination
of the crystalline orientation and optical activation of the anisotropic
transport properties. These results make few-layer BP a promising candidate for
future electronics.


title:
Recollements of Cohen-Macaulay Auslander algebras and Gorenstein derived
  categories

abstract:
  Let $A$, $B$ and $C$ be associative rings with identity. Using a result of
Koenig we show that if we have a $\mathbb{D}^{{\rm{b}}}({\rm{{mod\mbox{-}}}} )$
level recollement, writing $A$ in terms of $B$ and $C$, then we get a
$\mathbb{D}^-({\rm{Mod\mbox{-}}} )$ level recollement of certain functor
categories, induces from the module categories of $A$, $B$ and $C$. As an
application, we generalise the main theorem of Pan [Sh. Pan, Derived
equivalences for Cohen-Macaulay Auslander algebras, J. Pure Appl. Algebra, 216
(2012), 355-363] in terms of recollements of Gorenstein artin algebras.
Moreover, we show that being Gorenstein as well as being of finite
Cohen-Macaulay type, are invariants with respect to
$\mathbb{D}^{{\rm{b}}}_{{{\mathcal{G}p}}}({\rm{{mod\mbox{-}}}})$ level
recollements of virtually Gorenstein algebras, where
$\mathbb{D}^{{\rm{b}}}_{{{\mathcal{G}p}}}$ denotes the Gorenstein derived
category.


title: An information theoretical analysis of quantum optimal control

abstract:
  We show that if an efficient classical representation of the dynamics exists,
optimal control problems on many-body quantum systems can be solved efficiently
with finite precision. We show that the size of the space of parameters
necessary to solve quantum optimal control problems defined on pure, mixed
states and unitaries is polynomially bounded from the size of the of the set of
reachable states in polynomial time. We provide a bound for the minimal time
necessary to perform the optimal process given the bandwidth of the control
pulse, that is the continuous version of the Solovay-Kitaev theorem. We explore
the connection between entanglement present in the system and complexity of the
control problem, showing that one-dimensional slightly entangled dynamics can
be efficiently controlled. Finally, we quantify how noise affects the presented
results.


title:
Hierarchy of Gene Expression Data is Predictive of Future Breast Cancer
  Outcome

abstract:
  We calculate measures of hierarchy in gene and tissue networks of breast
cancer patients. We find that the likelihood of metastasis in the future is
correlated with increased values of network hierarchy for expression networks
of cancer-associated genes, due to correlated expression of cancer-specific
pathways. Conversely, future metastasis and quick relapse times are negatively
correlated with values of network hierarchy in the expression network of all
genes, due to dedifferentiation of gene pathways and circuits. These results
suggest that hierarchy of gene expression may be useful as an additional
biomarker for breast cancer prognosis.


title:
Physical Model of the Immune Response of Bacteria Against Bacteriophage
  Through the Adaptive CRISPR-Cas Immune System

abstract:
  Bacteria and archaea have evolved an adaptive, heritable immune system that
recognizes and protects against viruses or plasmids. This system, known as the
CRISPR-Cas system, allows the host to recognize and incorporate short foreign
DNA or RNA sequences, called `spacers' into its CRISPR system. Spacers in the
CRISPR system provide a record of the history of bacteria and phage
coevolution. We use a physical model to study the dynamics of this coevolution
as it evolves stochastically over time. We focus on the impact of mutation and
recombination on bacteria and phage evolution and evasion. We discuss the
effect of different spacer deletion mechanisms on the coevolutionary dynamics.
We make predictions about bacteria and phage population growth, spacer
diversity within the CRISPR locus, and spacer protection against the phage
population.


title:
The Metallicities of the Broad Emission Line Regions in the
  Nitrogen-Loudest Quasars

abstract:
  We measured the metallicity Z in the broad emission line regions (BELRs) of
43 SDSS quasars with the strongest N IV] and N III] emission lines. These
N-Loud QSOs have unusually low black hole masses. We used the intensity ratio
of N lines to collisionally-excited emission lines of other heavy elements to
find metallicities in their BELR regions. We found that 7 of the 8
line-intensity ratios that we employed give roughly consistent metallicities as
measured, but that for each individual QSO their differences from the mean of
all metallicity measurements depends on the ionization potential of the ions
that form the emission lines. After correcting for this effect, the different
line-intensity ratios give metallicities that generally agree to within the
0.24 dex uncertainty in the measurements of the line-intensity ratios. The
metallicities are very high, with mean log Z for the whole sample of 5.5 Z_sun
and a maximum of 18 Z_sun. Our results argue against the possibility that the
strong N lines represent an overabundance only of N but not of all heavy
elements. They are compatible with either (1) the BELR gas has been chemically
enriched by the general stellar population in the central bulge of the host
galaxy but the Locally Optimally-emitting Cloud model used in the analysis
needs some fine tuning, or (2) that instead this gas has been enriched by
intense star formation on the very local scale of the active nucleus that has
resulted in an abundance gradient within the BELR.


title:
WaterFowl, a Compact, Self-indexed RDF Store with Inference-enabled
  Dictionaries

abstract:
  In this paper, we present a novel approach -- called WaterFowl -- for the
storage of RDF triples that addresses some key issues in the contexts of big
data and the Semantic Web. The architecture of our prototype, largely based on
the use of succinct data structures, enables the representation of triples in a
self-indexed, compact manner without requiring decompression at query answering
time. Moreover, it is adapted to efficiently support RDF and RDFS entailment
regimes thanks to an optimized encoding of ontology concepts and properties
that does not require a complete inference materialization or extensive query
rewriting algorithms. This approach implies to make a distinction between the
terminological and the assertional components of the knowledge base early in
the process of data preparation, i.e., preprocessing the data before storing it
in our structures. The paper describes the complete architecture of this system
and presents some preliminary results obtained from evaluations conducted on
our first prototype.


title: One-dimensional disordered Ising models by replica and cavity methods

abstract:
  Using a formalism based on the spectral decomposition of the replicated
transfer matrix for disordered Ising models, we obtain several results that
apply both to isolated one-dimensional systems and to locally tree-like graph
and factor graph (p-spin) ensembles. We present exact analytical expressions,
which can be efficiently approximated numerically, for many types of
correlation functions and for the average free energies of open and closed
finite chains. All the results achieved, with the exception of those involving
closed chains, are then rigorously derived without replicas, using a
probabilistic approach with the same flavour of cavity method.


title:
Regularization by sup-inf convolutions on Riemannian manifolds: an
  extension of Lasry-Lions theorem to manifolds of bounded curvature

abstract:
  We show how Lasry-Lions's result on regularization of functions defined on
$\mathbb{R}^n$ or on Hilbert spaces by sup-inf convolutions with squares of
distances can be extended to (finite or infinite dimensional) Riemannian
manifolds $M$ of bounded sectional curvature. More specifically, among other
things we show that if the sectional curvature $K$ of $M$ satisfies $-K_0\leq
K\leq K_0$ on $M$ for some $K_0>0$, and if the injectivity and convexity radii
of $M$ are strictly positive, then every bounded, uniformly continuous function
$f:M\to\mathbb{R}$ can be uniformly approximated by globally $C^{1,1}$
functions defined by $$ (f_{\lambda})^{\mu}=\sup_{z\in M}\inf_{y\in
M}\{f(y)+\frac{1}{2\lambda} d(z,y)^{2}-\frac{1}{2\mu}d(x,z)^2\} $$ as $\lambda,
\mu\to 0^{+}$, with $0<\mu<\lambda/2$. Our definition of (global) $C^{1,1}$
smoothness is intrinsic and natural, and it reduces to the usual one in flat
spaces, but we warn the reader that, in the noncompact case, this definition
differs from other notions of (rather local) $C^{1,1}$ smoothness that have
been recently used, for instance, by A. Fathi and P. Bernard (based on charts).
The importance of this regularization method lies (rather than on the degree of
smoothness obtained) on the fact that the correspondence $f\mapsto
(f_{\lambda})^{\mu}$ is explicit and preserves many significant geometrical
properties that the given functions $f$ may have, such as invariance by a set
of isometries, infima, sets of minimizers, ordering, local or global
Lipschitzness, and (only when one additionally assumes that $K\leq 0$) local or
global convexity. We also give two examples showing that this result completely
fails, even for (nonflat) Cartan-Hadamard manifolds, whenever $f$ or $K$ are
not bounded.


title:
An\'alisis e implementaci\'on de algoritmos evolutivos para la
  optimizaci\'on de simulaciones en ingenier\'ia civil. (draft)

abstract:
  This paper studies the applicability of evolutionary algorithms,
particularly, the evolution strategies family in order to estimate a
degradation parameter in the shear design of reinforced concrete members. This
problem represents a great computational task and is highly relevant in the
framework of the structural engineering that for the first time is solved using
genetic algorithms.
  You are viewing a draft, the authors appreciate corrections, comments and
suggestions to this work.


title:
Spectroscopy of the enigmatic short-period cataclysmic variable IR Com
  in an extended low state

abstract:
  We report the occurrence of a deep low state in the eclipsing short-period
cataclysmic variable IR Com, lasting more than two years. Spectroscopy obtained
in this state shows the system as a detached white dwarf plus low-mass
companion, indicating that accretion has practically ceased. The spectral type
of the companion derived from the SDSS spectrum is M6-7, somewhat later than
expected for the orbital period of IR Com. Its radial velocity amplitude,
K_2=419.6+-3.4 km/s, together with the inclination of 75-90deg implies
0.8Msun<Mwd<1.0Msun. We estimate the white dwarf temperature to be ~15000K, and
the absence of Zeeman splitting in the Balmer lines rules out magnetic fields
in excess of ~5 MG. IR Com still defies an unambiguous classification, in
particular the occurrence of a deep, long low state is so far unique among
short-period CVs that are not strongly magnetic.


title:
Migdal's theorem and electron-phonon vertex corrections in Dirac
  materials

abstract:
  Migdal's theorem plays a central role in the physics of electron-phonon
interactions in metals and semiconductors, and has been extensively studied
theoretically for parabolic band electronic systems in three-, two-, and
one-dimensional systems over the last fifty years. In the current work, we
theoretically study the relevance of Migdal's theorem in graphene and Weyl
semimetals which are examples of 2D and 3D Dirac materials, respectively, with
linear and chiral band dispersion. Our work also applies to 2D and 3D
topological insulator systems. In Fermi liquids, the renormalization of the
electron-phonon vertex scales as the ratio of sound ($v_s$) to Fermi ($v_F$)
velocity, which is typically a small quantity. In two- and three-dimensional
quasirelativistic systems, such as undoped graphene and Weyl semimetals, the
one loop electron-phonon vertex renormalization, which also scales as
$\eta=v_s/v_F$ as $\eta \rightarrow 0$, is, however, enhanced by an ultraviolet
\emph{logarithmic divergent correction}, arising from the linear, chiral Dirac
band dispersion. Such enhancement of the electron-phonon vertex can be
significantly softened due to the logarithmic increment of the Fermi velocity,
arising from the long range Coulomb interaction, and therefore, the
electron-phonon vertex correction does not have a logarithmic divergence at low
energy. Otherwise, the Coulomb interaction does not lead to any additional
renormalization of the electron-phonon vertex. Therefore, electron-phonon
vertex corrections in two- and three-dimensional Dirac fermionic systems scale
as $v_s/v^0_F$, where $v^0_F$ is the bare Fermi velocity, and small when $v_s
\ll v^0_F$. These results, although explicitly derived for the intrinsic
undoped systems, should hold even when the chemical potential is tuned away
from the Dirac points.


title:
Dust grain growth and the formation of the extremely primitive star SDSS
  J102915+172927

abstract:
  Dust grains in low-metallicity star-forming regions may be responsible for
the formation of the first low-mass stars. The minimal conditions to activate
dust-induced fragmentation require the gas to be pre-enriched above a critical
dust-to-gas mass ratio Dcr=[2.6--6.3]x10^-9 with the spread reflecting the
dependence on the grain properties. The recently discovered Galactic halo star
SDSS J102915+172927 has a stellar mass of 0.8 Msun and a metallicity of
Z=4.5x10^-5 Zsun and represents an optimal candidate for the dust-induced
low-mass star formation. Indeed, for the two most plausible Population III
supernova progenitors, with 20 Msun and 35 Msun, the critical dust-to-gas mass
ratio can be overcome provided that at least 0.4 Msun of dust condenses in the
ejecta, allowing for moderate destruction by the reverse shock. Here we show
that even if dust formation in the first supernovae is less efficient or strong
dust destruction does occur, grain growth during the collapse of the parent gas
cloud is sufficiently rapid to activate dust cooling and likely fragmentation
into low-mass and long-lived stars. Silicates and magnetite grains can
experience significant grain growth in the density range 10^9 /cc < nH<10^12
/cc by accreting gas-phase species (SiO, SiO2, and Fe) until their gas-phase
abundance drops to zero, reaching condensation efficiencies =1. The
corresponding increase in the dust-to-gas mass ratio allows dust-induced
cooling and fragmentation to be activated at 10^12 /cc < nH < 10^14 /cc, before
the collapsing cloud becomes optically thick to continuum radiation. We show
that for all the initial conditions that apply to the parent cloud of SDSS
J102915+172927, dust-driven fragmentation is able to account for the formation
of the star.


title:
A Mean-Variance Control Framework for Platoon Control Problems: Weak
  Convergence Results and Applications on Reduction of Complexity

abstract:
  This paper introduces a new approach of treating platoon systems using
mean-variance control formulation. The underlying system is a controlled
switching diffusion in which the random switching process is a continuous-time
Markov chain. This switching process is used to represent random environment
and other random factors that cannot be given by stochastic differential
equations driven by a Brownian motion. The state space of the Markov chain is
large in our setup, which renders practically infeasible a straightforward
implementation of the mean-variance control strategy obtained in the
literature. By partitioning the states of the Markov chain into sub-groups (or
clusters) and then aggregating the states of each cluster as a super state, we
are able to obtain a limit system of much reduced complexity. The justification
of the limit system is rigorously supported by establishing certain weak
convergence results.


title: Establishing an analogue population for the most distant galaxies

abstract:
  Lyman break analogues (LBAs) are local galaxies selected to match a more
distant (usually z~3) galaxy population in luminosity, UV-spectral slope and
physical characteristics, and so provide an accessible laboratory for exploring
their properties. However, as the Lyman break technique is extended to higher
redshifts, it has become clear that the Lyman break galaxies (LBGs) at z~3 are
more massive, luminous, redder, more extended and at higher metallicities than
their z~5 counterparts. Thus extrapolations from the existing LBA samples
(which match z=3 properties) have limited value for characterising z>5
galaxies, or inferring properties unobservable at high redshift. We present a
new pilot sample of twenty-one compact star forming galaxies in the local
(0.05<z<0.25) Universe, which are tuned to match the luminosities and star
formation volume densities observed in z>~5 LBGs. Analysis of optical emission
line indices suggests that these sources have typical metallicities of a few
tenths Solar (again, consistent with the distant population). We also present
radio continuum observations of a subset of this sample (13 sources) and
determine that their radio fluxes are consistent with those inferred from the
ultraviolet, precluding the presence of a heavily obscured AGN or significant
dusty star formation.


title:
Gravitational instability of planetary gaps and its effect on orbital
  migration

abstract:
  Gap formation by giant planets in self-gravitating disks may lead to a
gravitational edge instability (GEI). We demonstrate this GEI with global 3D
and 2D self-gravitating disk-planet simulations using the ZEUS, PLUTO and FARGO
hydrodynamic codes. High resolution 2D simulations show that an unstable outer
gap edge can lead to outwards orbital migration. Our results have important
implications for theories of giant planet formation in massive disks.


title: Obscured accretion from AGN surveys

abstract:
  Recent models of super-massive black hole (SMBH) and host galaxy joint
evolution predict the presence of a key phase where accretion, traced by
obscured Active Galactic Nuclei (AGN) emission, is coupled with powerful star
formation. Then feedback processes likely self-regulate the SMBH growth and
quench the star-formation activity. AGN in this important evolutionary phase
have been revealed in the last decade via surveys at different wavelengths. On
the one hand, moderate-to-deep X-ray surveys have allowed a systematic search
for heavily obscured AGN, up to very high redshifts (z~5). On the other hand,
infrared/optical surveys have been invaluable in offering complementary methods
to select obscured AGN also in cases where the nuclear X-ray emission below 10
keV is largely hidden to our view. In this review I will present my personal
perspective of the field of obscured accretion from AGN surveys.


title:
Strong Biases in Estimating the Time Dependence of Mass Accretion Rates
  in Young Stars

abstract:
  The temporal decay of mass accretion in young stars is a fundamental tracer
of the early evolution of circumstellar disks. Through population syntheses, we
study how correlated uncertainties between the estimated parameters of young
stars (luminosity, temperature, mass, age) and mass accretion rates Mdot, as
well as observational selection effects, can bias the temporal decay of mass
accretion rates (Mdot t^-eta) inferred from a comparison of measured Mdot with
isochronal ages in young stellar clusters. We find that the presence of
realistic uncertainties reduces the measured value of eta by up to a factor of
3, leading to the inference of shallower decays than the true value. This
suggests a much faster temporal decay of Mdot than generally assumed. When
considering the minimum uncertainties in ages affecting the Orion Nebula
Cluster, the observed value eta~1.4, typical of Galactic star forming regions,
can only be reproduced if the real decay exponent is eta>4. This effect becomes
more severe if one assumes that observational uncertainties are larger, as
required by some fast star formation scenarios. Our analysis shows that while
selection effects due to sample incompleteness do bias eta, they can not alter
this main result and strengthen it in many cases. A remaining uncertainty in
our work is that it applies to the most commonly used and simple relationship
between Mdot, the accretion luminosity and the stellar parameters. We briefly
explore how a more complex interplay between these quantities might change the
results.


title: The First Hypervelocity Star from the LAMOST Survey

abstract:
  We report the first hypervelocity star (HVS) discovered from the LAMOST
spectroscopic survey. It is a B-type star with a heliocentric radial velocity
about 620 km/s, which projects to a Galactocentric radial velocity component of
~477 km/s. With a heliocentric distance of ~13 kpc and an apparent magnitude of
~13 mag, it is the nearest bright HVS currently known. With a mass of ~9Msun,
it is one of the three most massive HVSs discovered so far. The star is
clustered on the sky with many other known HVSs, with the position suggesting a
possible connection to Galactic center structures. With the current
poorly-determined proper motion, a Galactic center origin of this HVS remains
consistent with the data at the 1sigma level, while a disk run-away origin
cannot be excluded. We discuss the potential of the LAMOST survey to discover a
large statistical sample of HVSs of different types.


title:
On the role of ambient environments in the collapse of Bonnor-Ebert
  spheres

abstract:
  We consider the interaction between a marginally stable Bonnor-Ebert (BE)
sphere and the surrounding ambient medium. In particular, we explore how the
infall from an evolving ambient medium can trigger collapse of the sphere using
3-D adaptive mesh refinement simulations. We find the resulting collapse
dynamics to vary considerably with ambient density. In the highest ambient
density cases, infalling material drives a strong compression wave into the
cloud. It is the propagation of this wave through the cloud interior that
triggers the subsequent collapse. For lower ambient densities, we find the main
trigger of collapse to be a quasistatic adjustment of the BE sphere to
gravitational settling of the ambient gas. In all cases, we find that the
classic "outside-in" collapse mode for super-critical BE spheres is recovered
before a protostar (i.e. sink particle) forms. Our work supports scenarios in
which BE dynamics naturally begins with either a compression-wave or infall
dominated phase, and only later assumes the usual outside-in collapse behavior.


title:
Photometric studies of Abell 1664: The subtle effect a minor merger has
  on cluster galaxies

abstract:
  A combination of $BRI$ photometry and archival Chandra X-ray data have been
used to analyse the effects a minor merger has on the galaxy population of
A1664. We utilise adaptive smoothing techniques in the 2D spatial distribution
of cluster galaxies to reveal substructure $\sim$ 800 kpc South of the cluster
core. We identify this substructure as most likely the remnant core of a
merging group which has passed pericentre and responsible for triggering a cold
front in the cluster core. We define two samples to represent two different
environments within A1664 in accordance with the location of the substructure.
We apply a morphological analysis using CAS, M$_{20}$ and Gini to these samples
to deduce if there has been any significant effect on the cluster galaxies due
to this interaction. We find there are more asymmetric galaxies found in the
inner sample (at the 3.7$\sigma$ level) which is likely due to galaxy-galaxy
interactions as the merging group passed through core passage. No other
differences were found between the inner and outer cluster in our morphological
analysis, which we attribute to the limited resolution of our imagery. The
colour profiles of the galaxies are found to be consistent with the
morphology-density relation suggesting there is no unique environmental effect
in A1664 that has enhanced galaxy transformations. This study favours the star
formation of cluster galaxies being quenched well before it is able to interact
with the merging group and demonstrates that a minor cluster merger has little
effect on the observable parameters of cluster galaxies such as morphology and
colour.


title: Does the hierarchy problem generate the seesaw scale?

abstract:
  We find that minimizing the number of fine tuning relations in
non-supersymmetric models can determine the scales at which some gauge
symmetries beyond the standard model must break. We show that $SU(2)_R$ and
$B-L$ gauge symmetries of the minimal left-right symmetric model must break at
a scale $10^{15} GeV$ or higher, determined by the hierarchy problem and small
ratios of quark masses, if parameters that break chiral or $\mu$-symmetries
(and therefore can be naturally small), are not fine-tuned. This provides the
$raison \ d'\hat{e}tre$ for the seesaw scale $\sim 10^{15}GeV$ indicated by
neutrino experiments. Small ratios of fermion (quark) masses, which are natural
in the standard model due to approximate chiral symmetry, will have to be fine
tuned in minimal left right model if $SU(2)_R \times U(1)_{B-L}$ breaks at a
lower scale.


title:
Can AGN feedback break the self-similarity of galaxies, groups, and
  clusters?

abstract:
  It is commonly thought that AGN feedback can break the self-similar scaling
relations of galaxies, groups, and clusters. Using high-resolution 3D
hydrodynamic simulations, we isolate the impact of AGN feedback on the $L_{\rm
x}-T_{\rm x} $ relation, testing the two archetypal and common regimes,
self-regulated mechanical feedback and a quasar thermal blast. We find that AGN
feedback has severe difficulty in breaking the relation in a consistent way.
The similarity breaking is directly linked to the gas evacuation within
$R_{500}$, while the central cooling times are inversely proportional to the
core density. Breaking self-similarity implies thus breaking the cool core,
morphing all systems to non-cool-core objects, which is in clear contradiction
with the observed data populated by several cool-core systems. Self-regulated
feedback, which quenches cooling flows and preserves cool cores, prevents the
dramatic evacuation and similarity breaking at any scale; the relation scatter
is also limited. The impulsive thermal blast can break the core-included
$L_{\rm x}-T_{\rm x}$ at $T_{500} < 1$ keV, but substantially empties and
overheats the halo, generating a perennial non-cool-core group, as experienced
by cosmological simulations. Even with partial evacuation, massive systems
remain overheated. We show the action of purely AGN feedback is to lower the
luminosity and heating the gas, perpendicular to the fit.


title:
Consistent Compactification of Double Field Theory on Non-geometric Flux
  Backgrounds

abstract:
  In this paper, we construct non-trivial solutions to the $2D$-dimensional
field equations of Double Field Theory (DFT) by using a consistent
Scherk-Schwarz ansatz. The ansatz identifies $2(D-d)$ internal directions with
a twist $U^M{}_N$ which is directly connected to the covariant fluxes
$\mathcal{F}_{ABC}$. It exhibits $2(D-d)$ linear independent generalized
Killing vectors $K_I{}^J$ and gives rise to a gauged supergravity in $d$
dimensions. We analyze the covariant fluxes and the corresponding gauged
supergravity with a Minkowski vacuum. We calculate fluctuations around such
vacua and show how they gives rise to massive scalars field and vectors field
with a non-abelian gauge algebra. Because DFT is a background independent
theory, these fields should directly correspond the string excitations in the
corresponding background. For $(D-d)=3$ we perform a complete scan of all
allowed covariant fluxes and find two different kinds of backgrounds: the
single and the double elliptic case. The later is not T-dual to a geometric
background and cannot be transformed to a geometric setting by a field
redefinition either. While this background fulfills the strong constraint, it
is still consistent with the Killing vectors depending on the coordinates and
the winding coordinates, thereby giving a non-geometric patching. This
background can therefore not be described in Supergravity or Generalized
Geometry.


title: The Fermi GBM Gamma-Ray Burst Spectral Catalog: Four Years Of Data

abstract:
  In this catalog we present the updated set of spectral analyses of GRBs
detected by the Fermi Gamma-Ray Burst Monitor (GBM) during its first four years
of operation. It contains two types of spectra, time-integrated spectral fits
and spectral fits at the brightest time bin, from 943 triggered GRBs. Four
different spectral models were fitted to the data, resulting in a compendium of
more than 7500 spectra. The analysis was performed similarly, but not
identically to Goldstein et al. 2012. All 487 GRBs from the first two years
have been re-fitted using the same methodology as that of the 456 GRBs in years
three and four. We describe, in detail, our procedure and criteria for the
analysis, and present the results in the form of parameter distributions both
for the observer-frame and rest-frame quantities. The data files containing the
complete results are available from the High-Energy Astrophysics Science
Archive Research Center (HEASARC).


title: Evolution of multiple supernova remnants

abstract:
  (Abridged) Heating of the interstellar medium by multiple supernovae (SNe)
explosions is at the heart of producing galaxy-scale outflows. We use
hydrodynamical simulations to study the efficiency of multiple SNe in heating
the interstellar medium (ISM) and filling the volume with gas of high
temperatures. We argue that it is important for SNe remnants to have a large
filling factor {\it and} a large heating efficiency. For this, they have to be
clustered in space and time, and keep exploding until the hot gas percolates
through the whole region, in order to compensate for the radiative loss. In the
case of a limited number of SNe, we find that although the filling factor can
be large, the heating efficiency declines after reaching a large value. In the
case of a continuous series of SNe, the hot gas ($T \ge 3 \times 10^6$ K) can
percolate through the whole region after the total volume filling factor
reaches a threshold of $\sim 0.3$. The efficiency of heating the gas to X-ray
temperatures can be $\ge 0.1$ after this percolation epoch, which occurs after
a period of $\approx 10$ Myr for a typical starburst SNe rate density of
$\nu_{\rm SN} \approx 10^{-9}$ pc$^{-3}$ yr$^{-1}$ and gas density of $n\approx
10$ cm$^{-3}$ in starburst nuclei regions. This matches the recent observations
of a time delay of similar order between the onset of star formation and
galactic outflows. The efficiency to heat gas up to X-ray temperatures ($\ge
10^{6.5}$ K) roughly scales as $\nu_{\rm SN}^{0.2} n^{-0.6}$. For a typical SNe
rate density and gas density in starburst nuclei, the heating efficiency is
$\sim 0.15$, also consistent with previous interpretations from X-ray
observations. We discuss the implications of our results with regard to
observational diagnostics of ionic ratios and emission measures in starburst
nuclei regions.