title:
An 8 hour characteristic time-scale in submillimetre light curves of
  Sagittarius A*

abstract:
  We compile and analyse long term (~10 year) submillimetre (1.3, 0.87, 0.43
mm, submm) wavelength light curves of the Galactic centre black hole,
Sagittarius A*. The 0.87 and 0.43 mm data are taken from the literature, while
the majority of the 1.3 mm light curve is from previously unpublished SMA and
CARMA data. We use Monte Carlo simulations to show that on minute to few hour
time-scales the variability is consistent with a red noise process with a 230
GHz power spectrum slope of 2.3+0.8-0.6 at 95% confidence. The light curve is
de-correlated (white noise) on very long (month to year) times. In order to
identify the transition time between red and white noise, we model the light
curves as a stochastic damped random walk process. The models allow a
quantitative estimate of this physical characteristic time-scale of 8-4+3 hours
at 230 GHz at 95% confidence, with consistent results at 345 and 690 GHz. This
corresponds to ~10 orbital times or ~1 inflow (viscous) time at R = 3 Rs, a
typical radius producing the 230 GHz emission as measured by very long baseline
interferometry and found in theoretical accretion flow and jet models. This
time-scale is significantly shorter (longer) than those measured at radio
(near-infrared, NIR) wavelengths, and is marginally inconsistent with the same
variability mechanism operating in the submm and NIR for the expected t ~ R^3/2
scaling. It is crudely consistent with the analogous time-scale inferred in
studies of quasar optical light curves after accounting for the difference in
emission radius. We find evidence that the submm variability persists at least
down to the ISCO, if not the event horizon. These results can be compared
quantitatively with similar analyses at different wavebands to test for
connections between the variability mechanisms, and with light curves from
theoretical models of accreting black holes.


title: Multiple scattering Sunyaev-Zeldovich signal I: lowest order effect

abstract:
  Future high-resolution, high-sensitivity Sunyaev-Zeldovich (SZ) observations
of individual clusters will allow us to study the dynamical state of the intra
cluster medium (ICM). To exploit the full potential of this new observational
window, it is crucial to understand the different contributions to the total SZ
signal. Here, we investigate the signature caused by multiple scatterings at
lowest order of the electron temperature. Previous analytic discussions of this
problem used the isotropic scattering approximation (ISA), which even for the
simplest cluster geometries is rather rough. We take a step forward and
consistently treat the anisotropy of the ambient radiation field caused by the
first scattering. We show that the multiple scattering SZ signal directly
probes line of sight anisotropies of the ICM, thereby delivering a new set of
SZ observables which could be used for 3D cluster-profile reconstruction. The
multiple scattering signal should furthermore correlate spatially with the
cluster's X-ray and SZ polarization signals, an effect that could allow
enhancing the detectability of this contribution.


title: A synchrotron jet from a post-AGB star

abstract:
  (Abridged) The evolution of low- and intermediate-initial-mass stars beyond
the asymptotic giant branch (AGB) remains poorly understood. High-velocity
outflows launched shortly after the AGB phase are thought to be the primary
shaping mechanism of bipolar and multipolar planetary nebulae (PNe). However,
little is known about the launching and driving mechanism for these jets, whose
momentum and energy often far exceed the energy that can be provided by
radiation pressure alone. Here, we report direct evidence of a magnetically
collimated jet shaping the bipolar morphology of the circumstellar envelope of
a post-AGB star. We present radio continuum observations of the post-AGB star
IRAS 15445-5449 which has water masers tracing a fast bipolar outflow. Our
observations confirm the earlier observed steep negative spectral index of the
spectral energy distribution (SED) above 3 GHz, and resolve, for the first
time, the emission to originate from a radio jet, proving the existence of such
jets around a post-AGB star. The SED is consistent with a synchrotron jet
embedded in a sheath of thermal electrons. We find a close correspondence
between the extent and direction of the synchrotron jet and the bipolar shape
of the object observed at other wavelenghts, suggesting that the jet is
responsible for the source morphology. The jet is collimated by a magnetic
field of the order of mG at almost 7000 AU from the central star. We recover
observations from the ATCA archive that indicate that the emission measure of
the thermal component has increased by a factor of three between 1998 and 2005
after which it has remained constant. The short timescale evolution of the
radio emission suggests a short lifetime for the jet.


title:
Precious Metals in SDSS Quasar Spectra II: Tracking the Evolution of
  Strong, 0.4 < z < 2.3 MgII Absorbers with Thousands of Systems

abstract:
  We have performed an analysis of over 34,000 MgII doublets at 0.36 < z < 2.29
in Sloan Digital Sky Survey (SDSS) Data-Release 7 quasar spectra; the catalog,
advanced data products, and tools for analysis are publicly available. The
catalog was divided into 14 small redshift bins with roughly 2500 doublets in
each, and from Monte-Carlo simulations, we estimate 50% completeness at rest
equivalent width W_r ~ 0.8 Angstrom. The equivalent-width frequency
distribution is described well by an exponential model at all redshifts, and
the distribution becomes flatter with increasing redshift, i.e., there are more
strong systems relative to weak ones. Direct comparison with previous SDSS MgII
surveys reveal that we recover at least 70% of the doublets in these other
catalogs, in addition to detecting thousands of new systems. We discuss how
these surveys come by their different results, which qualitatively agree but,
due to the very small uncertainties, differ by a statistically significant
amount. The estimated physical cross-section of MgII-absorbing galaxy halos
increased three-fold, approximately, from z = 0.4 --> 2.3, while the W_r >= 1
Angstrom absorber line density grew, dN_MgII/dX, by roughly 45%. Finally, we
explore the different evolution of various absorber populations - damped
Lyman-alpha absorbers, Lyman-limit systems, strong CIV absorbers, and strong
and weaker MgII systems - across cosmic time (0 < z < 6).


title:
Cosmological Information in the Intrinsic Alignments of Luminous Red
  Galaxies

abstract:
  The intrinsic alignments of galaxies are usually regarded as a contaminant to
weak gravitational lensing observables. The alignment of Luminous Red Galaxies,
detected unambiguously in observations from the Sloan Digital Sky Survey, can
be reproduced by the linear tidal alignment model of Catelan, Kamionkowski &
Blandford (2001) on large scales. In this work, we explore the cosmological
information encoded in the intrinsic alignments of red galaxies. We make
forecasts for the ability of current and future spectroscopic surveys to
constrain local primordial non-Gaussianity and Baryon Acoustic Oscillations
(BAO) in the cross-correlation function of intrinsic alignments and the galaxy
density field. For the Baryon Oscillation Spectroscopic Survey, we find that
the BAO signal in the intrinsic alignments is marginally significant with a
signal-to-noise ratio of 1.8 and 2.2 with the current LOWZ and CMASS samples of
galaxies, respectively, and increasing to 2.3 and 2.7 once the survey is
completed. For the Dark Energy Spectroscopic Instrument and for a spectroscopic
survey following the EUCLID redshift selection function, we find
signal-to-noise ratios of 12 and 15, respectively. Local type primordial
non-Gaussianity, parametrized by fNL = 10, is only marginally significant in
the intrinsic alignments signal with signal-to-noise ratios < 2 for the three
surveys considered.


title: A Simple Disk Wind Model for Broad Absorption Line Quasars

abstract:
  Approximately 20% of quasi-stellar objects (QSOs) exhibit broad, blue-shifted
absorption lines in their ultraviolet spectra. Such features provide clear
evidence for significant outflows from these systems, most likely in the form
of accretion disk winds. These winds may represent the "quasar" mode of
feedback that is often invoked in galaxy formation/evolution models, and they
are also key to unification scenarios for active galactic nuclei (AGN) and
QSOs. To test these ideas, we construct a simple benchmark model of an
equatorial, biconical accretion disk wind in a QSO and use a Monte Carlo
ionization/radiative transfer code to calculate the ultraviolet spectra as a
function of viewing angle. We find that for plausible outflow parameters,
sightlines looking directly into the wind cone do produce broad, blue-shifted
absorption features in the transitions typically seen in broad absorption line
QSOs. However, our benchmark model is intrinsically X-ray weak in order to
prevent overionization of the outflow, and the wind does not yet produce
collisionally excited line emission at the level observed in non-BAL QSOs. As a
first step towards addressing these shortcomings, we discuss the sensitivity of
our results to changes in the assumed X-ray luminosity and mass-loss rate,
Mdot(wind). In the context of our adopted geometry, Mdot(wind) ~ Mdot(acc) is
required in order to produce significant BAL features. The kinetic luminosity
and momentum carried by such outflows would be sufficient to provide
significant feedback.


title: Update on the Cetus Polar Stream and its Progenitor

abstract:
  We trace the Cetus Polar Stream (CPS) with blue horizontal branch (BHB) and
red giant stars (RGBs) from Data Release 8 of the Sloan Digital Sky Survey
(SDSS DR8). Using a larger dataset than was available previously, we are able
to refine the measured distance and velocity to this tidal debris star stream
in the south Galactic cap. Assuming the tidal debris traces the progenitor's
orbit, we fit an orbit to the CPS and find that the stream is confined between
~24-36 kpc on a rather polar orbit inclined 87 degrees to the Galactic plane.
The eccentricity of the orbit is 0.20, and the period ~700 Myr. If we instead
matched N-body simulations to the observed tidal debris, these orbital
parameters would change by 10% or less. The CPS stars travel in the opposite
direction to those from the Sagittarius tidal stream in the same region of the
sky. Through N-body models of satellites on the best-fitting orbit, and
assuming that mass follows light, we show that the stream width, line-of-sight
depth, and velocity dispersion imply a progenitor of at least 10^8 solar
masses. However, the density of stars along the stream requires either a
disruption time on the order of one orbit, or a stellar population that is more
centrally concentrated than the dark matter. We suggest that an ultra-faint
dwarf galaxy progenitor could reproduce a large stream width and velocity
dispersion without requiring a very recent deflection of the progenitor into
its current orbit. We find that most Cetus stars have metallicities of -2.5 <
[Fe/H] < -2.0, similar to the observed metallicities of the ultra-faint dwarfs.
Our simulations suggest that the parameters of the dwarf galaxy progenitors,
including their dark matter content, could be constrained by observations of
their tidal tails through comparison of the debris with N-body simulations.


title: Effective field theory for proton halo nuclei

abstract:
  We use halo effective field theory to analyze the universal features of
proton halo nuclei bound due to a large S-wave scattering length. With a
Lagrangian built from effective core and valence-proton fields, we derive a
leading-order expression for the charge form factor. Within the same framework
we also calculate the radiative proton capture cross section. Our general
results at leading order are applied to study the excited 1/2+ state of
Fluorine-17, and we give results for the charge radius and the astrophysical
S-factor.


title: Clustering Measurements of broad-line AGNs: Review and Future

abstract:
  Despite substantial effort, the precise physical processes that lead to the
growth of super-massive black holes in the centers of galaxies are still not
well understood. These phases of black hole growth are thought to be of key
importance in understanding galaxy evolution. Forthcoming missions such as
eROSITA, HETDEX, eBOSS, BigBOSS, LSST, and Pan-STARRS will compile by far the
largest ever Active Galactic Nuclei (AGNs) catalogs which will allow us to
measure the spatial distribution of AGNs in the universe with unprecedented
accuracy. For the first time, AGN clustering measurements will reach a level of
precision that will not only allow for an alternative approach to answering
open questions in AGN/galaxy co-evolution but will open a new frontier,
allowing us to precisely determine cosmological parameters. This paper reviews
the large-scale clustering measurements of broad line AGNs. We summarize how
clustering is measured and which constraints can be derived from AGN clustering
measurements, we discuss recent developments, and we briefly describe future
projects that will deliver extremely large AGN samples which will enable AGN
clustering measurements of unprecedented accuracy. In order to maximize the
scientific return on the research fields of AGN/galaxy evolution and cosmology,
we advise that the community develop a full understanding of the systematic
uncertainties which will, in contrast to today's measurement, be the dominant
source of uncertainty.


title: The T-algebra spectral sequence: Comparisons and applications

abstract:
  In previous work with Niles Johnson the author constructed a spectral
sequence for computing homotopy groups of spaces of maps between structured
objects such as G-spaces and E_n-ring spectra. In this paper we study special
cases of this spectral sequence in detail. Under certain assumptions, we show
that the Goerss-Hopkins spectral sequence and the T-algebra spectral sequence
agree. Under further assumptions, we can apply a variation of an argument due
to Jennifer French and show that these spectral sequences agree with the
unstable Adams spectral sequence.
  From these equivalences we obtain information about filtration and
differentials. Using these equivalences we construct the homological and
cohomological Bockstein spectral sequences topologically. We apply these
spectral sequences to show that Hirzebruch genera can be lifted to
E_\infty-ring maps and that the forgetful functor from E_\infty-algebras in
H\overline{F}_p-modules to H_\infty-algebras is neither full nor faithful.


title:
Setting the Stage for Circumstellar Interaction in Core-Collapse
  Supernovae II: Wave-Driven Mass Loss in Supernova Progenitors

abstract:
  Supernovae (SNe) powered by interaction with circumstellar material provide
evidence for intense stellar mass loss during the final years leading up to
core collapse. We have argued that during and after core neon burning, internal
gravity waves excited by core convection can tap into the core fusion power and
transport a super-Eddington energy flux out to the stellar envelope,
potentially unbinding up to ~ 1 solar mass of material. In this work, we
explore the internal conditions of SN progenitors using the MESA 1-D stellar
evolution code, in search of those most susceptible to wave-driven mass loss.
We focus on simple, order of magnitude considerations applicable to a wide
range of progenitors. Wave-driven mass loss during core neon and oxygen fusion
happens preferentially in either lower mass (<~ 20 solar mass ZAMS) stars or
massive, sub-solar metallicity stars. Roughly 20 per cent of the SN progenitors
we survey can excite ~ 10^46 - 10^48 erg of energy in waves that can
potentially drive mass loss within a few months to a decade of core collapse.
This energy can generate a circumstellar environment with 10^-3 - 1 solar mass
reaching ~ 100 AU before explosion. We predict a correlation between the energy
associated with pre-SN mass ejection and the time to core collapse, with the
most intense mass loss preferentially happening closer to core collapse. During
silicon burning, a ~ 5 day long phase for our progenitor models, wave energy
may inflate ~ 10^-3 - 1 solar mass of the stellar envelope to ~ 10 - 100s of
solar radii. This suggests that some nominally compact SN progenitors (Type Ibc
progenitors) will have a significantly different SN shock breakout signature
than traditionally assumed. We discuss the implications of our results for the
core-collapse SN mechanism, Type IIn SNe, Type IIb SNe from extended
progenitors (e.g., SNe 1993j and 2011dh), and observed pre-SN outbursts.


title:
Synergies between neutrino oscillation experiments: An `adequate'
  configuration for LBNO

abstract:
  Determination of the neutrino mass hierarchy, octant of the mixing angle
theta_{23} and the CP violating phase delta_{CP} are the unsolved problems in
neutrino oscillation physics today. In this paper our aim is to obtain the
minimum exposure required for the proposed Long Baseline Neutrino Oscillation
(LBNO) experiment to determine the above unknowns. We emphasize on the
advantage of exploiting the synergies offered by the existing and upcoming
long-baseline and atmospheric neutrino experiments in economising the LBNO
configuration. In particular, we do a combined analysis for LBNO, T2K, NOvA and
INO. We consider three prospective LBNO setups -- CERN-Pyhasalmi (2290 km),
CERN-Slanic (1500 km) and CERN-Frejus (130 km) and evaluate the adequate
exposure required in each case. Our analysis shows that the exposure required
from LBNO can be reduced considerably due to the synergies arising from the
inclusion of the other experiments.


title:
Second Moments and simultaneous non-vanishing of GL(2) automorphic
  L-series

abstract:
  We obtain a second moment formula for the L-series of holomorphic cusp forms,
averaged over twists by Dirichlet characters modulo a fixed conductor Q. The
estimate obtained has no restrictions on Q, with an error term that has a close
to optimal power savings in the exponent. However, one of the contributions to
the main term is a special value of a shifted double Dirichlet series. We show
that this special value is small on average, and obtain a corresponding
estimate for a mean value of the second moment over Q. This mean value is
non-zero even when applied to a product of two distinct L-series, leading to a
simultaneous non-vanishing result. Our approach uses the theory of shifted
multiple Dirichlet series to obtain some refined estimates for double shifted
sums. These estimates are the key ingredient in the second moment estimate.


title: Spectra of Coset Sigma Models

abstract:
  We compute the complete 1-loop spectrum of anomalous dimensions for the bulk
fields of non-linear sigma models on symmetric coset (super)spaces G/H, both
with and without world-sheet supersymmetry. In addition, we provide two new
methods for the construction of partition functions in the infinite radius
limit and demonstrate their efficiency in the case of (super)sphere sigma
models. Our results apply to a large number of target spaces including
superspheres and superprojective spaces such as the N=2 sigma model on CP(3|4).


title: Structure factor of interacting one-dimensional helical systems

abstract:
  We calculate the dynamical structure factor S(q, {\omega}) of a weakly
interacting helical edge state in the presence of a magnetic field B. The
latter opens a gap of width 2B in the single-particle spectrum, which becomes
strongly nonlinear near the Dirac point. For chemical potentials |{\mu}| > B,
the system then behaves as a nonlinear helical Luttinger liquid, and a
mobile-impurity analysis reveals interaction-dependent power-law singularities
in S(q,{\omega}). For |{\mu}| < B, the low-energy excitations are gapped, and
we determine S(q,{\omega}) by using an analogy to exciton physics.


title:
Berry phase theory of Dzyaloshinskii-Moriya interaction and spin-orbit
  torques

abstract:
  Recent experiments on current-induced domain wall motion in chiral magnets
suggest important contributions both from spin-orbit torques (SOTs) and from
the Dzyaloshinskii-Moriya interaction (DMI). We derive a Berry phase expression
for the DMI and show that within this Berry phase theory DMI and SOTs are
intimately related, in a way formally analogous to the relation between orbital
magnetization (OM) and anomalous Hall effect (AHE). We introduce the concept of
the \textit{twist torque moment}, which probes the internal twist of wave
packets in chiral magnets in a similar way like the orbital moment probes the
wave packet's internal self rotation. We propose to interpret the Berry phase
theory of DMI as a theory of \textit{spiralization} in analogy to the modern
theory of OM. We show that the twist torque moment and the spiralization
together give rise to a Berry phase governing the response of the SOT to
thermal gradients, in analogy to the intrinsic anomalous Nernst effect. The
Berry phase theory of DMI is computationally very efficient because it only
needs the electronic structure of the collinear magnetic system as input. As an
application of the formalism we compute the DMI in Pt/Co, Pt/Co/O and Pt/Co/Al
magnetic trilayers and show that the DMI is highly anisotropic in these
systems.


title:
Braiding Statistics and Congruent Invariance of Twist Defects in Bosonic
  Bilayer Fractional Quantum Hall States

abstract:
  We describe the braiding statistics of topological twist defects in abelian
bosonic bilayer (mmn) fractional quantum Hall (FQH) states, which reduce to the
Z_n toric code when m=0. Twist defects carry non-abelian fractional
Majorana-like characteristics. We propose local statistical measurements that
distinguish the fractional charge, or species, of a defect-quasiparticle
composite. Degenerate ground states and basis transformations of a multi-defect
system are characterized by a consistent set of fusion properties. Non-abelian
unitary exchange operations are determined using half braids between defects,
and projectively represent the sphere braid group in a closed system. Defect
spin statistics are modified by equating exchange with 4\pi rotation. The
braiding S matrix is identified with a Dehn twist (instead of a \pi/2 rotation)
on a torus decorated with a non-trivial twofold branch cut, and represents the
congruent subgroup \Gamma_0(2) of modular transformations.


title:
The changing Lya optical depth in the range 6<z<9 from MOSFIRE
  spectroscopy of Y-dropouts

abstract:
  We present MOSFIRE spectroscopy of 13 candidate z~8 galaxies selected as
Y-dropouts as part of the BoRG pure parallel survey. We detect no significant
lya emission (our median 1-sigma rest frame equivalent width sensitivity is in
the range 2-16 AA). Using the Bayesian framework derived in a previous paper,
we perform a rigorous analysis of a statistical subsample of non-detections for
ten Y-dropouts, including data from the literature, to study the cosmic
evolution of the lya emission of Lyman Break Galaxies. We find that lya
emission is suppressed at z~8 by at least a factor of three with respect to z~6
continuing the downward trend found by previous studies of z-dropouts at z~7.
This finding suggests a dramatic evolution in the conditions of the
intergalactic or circumgalactic media in just 300 Myrs, consistent with the
onset of reionization or changes in the physical conditions of the first
generations of starforming regions.


title: Schottky-to-Ohmic Crossover in Carbon Nanotube Transistor Contacts

abstract:
  For carbon nanotube transistors, as for graphene, the electrical contacts are
a key factor limiting device performance. We calculate the device
characteristics as a function of nanotube diameter and metal workfunction.
Although the on-state current varies continuously, the transfer characteristics
reveal a relatively abrupt crossover from Schottky to ohmic contacts. We find
that typical high-performance devices fall surprisingly close to the crossover.
Surprisingly, tunneling plays an important role even in this regime, so that
current fails to saturate with gate voltage as was expected due to "source
exhaustion".


title: A perturbation basis for calculating NMR Diffusometry

abstract:
  An approximative method for solving the Bloch-Torrey equation in general
porous media is presented. The method expand the boundaries defining the porous
media using electrostatic charges. As a result the eigenvalue problem of the
Laplace operator in a confined geometry can approximately solved. Importantly
the approximative solution is orthogonal in the low-frequent region of Fourier
space. This gives a natural approach for studying spin magnetization in
presence of magnetic fields. The error in the approximation scales with N^{-2}
times the magnitude of each eigenvalue, where N is the size of the expansion
matrix. From a computational point of view, the calculations scale
quadratically with the number of basis functions using fast multipole methods.


title: Resonances from Quiver Theories at the LHC

abstract:
  We consider the collider signals of spin-one resonances present in
full-hierarchy quiver theories of electroweak symmetry breaking. These
four-dimensional theories result from the deconstruction of warped extra
dimensional models and have very distinct phenomenological features when the
number of sites is small. We study a class of generic scenarios in these
theories where the color gauge group as well as the electroweak sector,
propagate in the quiver diagram. These scenarios correspond to various specific
models of electroweak symmetry breaking and fermion masses. We focus on the
minimum resonant content and its main features: the presence of heavy and
narrow spin one resonances. We derive bounds from the LHC data on the
color-octet and color-singlet excited gauge bosons from their decays to jets
and top pairs, and show their dependence on the number of sites in the quiver.
We also compare them with the bounds derived from flavor violation.


title: Characterizing thermal conduction in polycrystalline graphene

abstract:
  Thermal conduction was explored and discussed through a combined theoretical
and simulation approach in this work. The thermal conductivity k of
polycrystalline graphene was calculated by molecular dynamics simulations based
on a hexagonal patch model in close consistence with microstructural
characterization in experiments. The effects of grain size, alignment, and
temperature were identified with discussion on the microscopic phonon
scattering mechanisms. The effective thermal conductivity is found to increase
with the grain size and decrease with the mismatch angle and dislocation
density at the grain boundaries. The 1/T temperature dependence of k is
significantly weakened in the polycrystals. The effect of grain boundaries in
modifying thermal transport properties of graphene was characterized by their
effective width and thermal conductivity as an individual phase, which was
later included in a predictive effective medium model that showed degraded
reduction in thermal conductivity for grain larger than a few microns.


title:
Realizing the analytic surgery group of Higson and Roe geometrically,
  Part I: The geometric model

abstract:
  We construct a geometric analog of the analytic surgery group of Higson and
Roe for the assembly mapping for free actions of a group with values in a
Banach algebra completion of the group algebra. We prove that the geometrically
defined group, in analogy with the analytic surgery group, fits into a six term
exact sequence with the assembly mapping and also discuss mappings with domain
the geometric group. In particular, given two finite dimensional unitary
representations of the same rank, we define a map in the spirit of $\eta$-type
invariants from the geometric group (with respect to assembly for the full
group $C^*$-algebra) to the real numbers.


title: Jet Quenching Parameter with Hyperscaling Violation

abstract:
  In this paper we study the behavior of jet quenching parameter in the
background metric with hyperscaling violation at finite temperature.The
background metric is covariant under a generalized Lifshitz scaling symmetry
with the dynamical exponent z and hyperscaling exponent $\theta$. We evaluate
the jet quenching parameter for certain range of these parameters consistent
with the Gubser bound conditions in terms of T, z and $\theta$. We compare our
results with those from conformal case and experimental data. Then we add a
constant electric field to this background and find its effect on the jet
quenching parameter.


title: Bootstrap Algebraic Multigrid for the 2D Wilson Dirac system

abstract:
  We develop an algebraic multigrid method for solving the non-Hermitian Wilson
discretization of the 2-dimensional Dirac equation. The proposed approach uses
a bootstrap setup algorithm based on a multigrid eigensolver. It computes test
vectors which define the least squares interpolation operators by working
mainly on coarse grids, leading to an efficient and integrated self learning
process for defining algebraic multigrid interpolation. The algorithm is
motivated by the \gamma-symmetry of the Dirac equation, which carries over to
the Wilson discretization. This discrete \gamma-symmetry is used to reduce a
general Petrov Galerkin bootstrap setup algorithm to a Galerkin method for the
Hermitian and indefinite formulation of the Wilson matrix. Kaczmarz relaxation
is used as the multigrid smoothing scheme in both the setup and solve phases of
the resulting Galerkin algorithm. The overall method is applied to the odd-even
reduced Wilson matrix, which also fulfills the discrete \gamma-symmetry.
Extensive numerical results are presented to motivate the design and
demonstrate the effectiveness of the proposed approach.


title: New nef divisors on $\bar{M}_{0,n}$

abstract:
  We give a direct proof, valid in arbitrary characteristic, of nefness for two
families of F-nef divisors on $\bar{M}_{0,n}$. The divisors we consider include
all type A level one conformal block divisors as well as divisors previously
not known to be nef.


title: On cubes of Frobenius extensions

abstract:
  Given a hypercube of Frobenius extensions between commutative algebras, we
provide a diagrammatic description of some natural transformations between
compositions of induction and restriction functors, in terms of colored
transversely-intersecting planar 1-manifolds. The relations arise in the first
and third authors' work on (singular) Soergel bimodules.


title: Searching for structure beyond parity in the two-qubit Dicke model

abstract:
  We try to classify the spectrum of the two-qubit Dicke model by calculating
two quantum information measures of its eigenstates: the Wooters concurrence
and the mutual quantum information. We are able to detect four spectral sets in
each parity subspace of the model: one set is regular and given by the product
of a Fock state of the field times the singlet Bell state of the qubits; the
rest are fairly regular and related to the triplet states of the Bell basis.
The singlet states become trapping states when we couple the Dicke model to an
environment of harmonic oscillators, making them candidates for generating
maximally entangled states in experimental realizations of ion trap quantum
electrodynamics (QED) and circuit QED. Furthermore, they are robust and survive
the inclusion of driving and dipole-dipole interactions, pointing to their use
for storing quantum correlations, and it is straightforward to provide a
generalization of these trapping states to the Dicke model with even number of
qubits.


title: Security Issues on Cloud Computing

abstract:
  The Cloud Computing concept offers dynamically scalable resources provisioned
as a service over the Internet.Economic benefits are the main driver for the
Cloud, since it promises the reduction of capital expenditure and operational
expenditure.In order for this to become reality, however, there are still some
challenges to be solved. Amongst these are security and trust issues, since the
user data has to be released to the Cloud and thus leaves the protection sphere
of the data owner. Most of the discussions on these topics are mainly driven by
arguments related to organisational means. This paper focuses on various
security issues arising from the usage of Cloud services and especially by the
rapid development of Cloud computing arena. It also discusses basic security
model followed by various High Level Security threats in the industry.


title: Branch points of area-minimizing projective planes

abstract:
  Minimal surfaces in a Riemannian manifold $M^n$ are surfaces which are
stationary for area: the first variation of area vanishes. In this paper we
focus on surfaces of the topological type of the real projective plane $\R
P^2$. We show that a minimal surface $f:\R P^2\to M^3$ which has the smallest
area, among those mappings which are not homotopic to a constant mapping, is an
immersion. That is, $f$ is free of branch points. As a major step toward
treating minimal surfaces of the type of the projective plane, we extend the
fundamental theorem of branched immersions to the nonorientable case. We also
resolve a question on the directions of branch lines posed by Courant in 1950.


title:
A spectrally accurate direct solution technique for frequency-domain
  scattering problems with variable media

abstract:
  This paper presents a direct solution technique for the scattering of
time-harmonic waves from a bounded region of the plane in which the wavenumber
varies smoothly in space.The method constructs the interior
Dirichlet-to-Neumann (DtN) map for the bounded region via bottom-up recursive
merges of (discretization of) certain boundary operators on a quadtree of
boxes.These operators take the form of impedance-to-impedance (ItI) maps. Since
ItI maps are unitary, this formulation is inherently numerically stable, and is
immune to problems of artificial internal resonances. The ItI maps on the
smallest (leaf) boxes are built by spectral collocation on tensor-product grids
of Chebyshev nodes. At the top level the DtN map is recovered from the ItI map
and coupled to a boundary integral formulation of the free space exterior
problem, to give a provably second kind equation.Numerical results indicate
that the scheme can solve challenging problems 70 wavelengths on a side to
9-digit accuracy with 4 million unknowns, in under 5 minutes on a desktop
workstation. Each additional solve corresponding to a different incident wave
(right-hand side) then requires only 0.04 seconds.


title:
Optimization of Bluetooth Audio Stream based on the Estimation of
  Proximity

abstract:
  The advent of Bluetooth wireless technology makes it possible to transmit
real-time audio in mobile devices. Bluetooth is cost-efficient and
power-efficient, but it is not suitable for traditional audio encoding and
real-time streaming due to limited bandwidth, high degree of error rates, and
the time-varying nature of the radio link. Therefore, audio streaming over
Bluetooth poses problems such as guzzling of both power and bandwidth. In order
to overcome the above mentioned problems, an algorithm is proposed in this work
to optimize the audio stream from the source to the sink by estimating the
proximity between them. The optimization is achieved by adjusting the bit rate
of the audio stream thus conserving power. We considered carefully various
Bluetooth signal parameters and the most suitable parameter for estimating the
proximity has been determined experimentally. The experiments were carried out
using Class II BS003 Bluesoleil dongle. This work will enable the Bluetooth
users to perform a seamless and optimized streaming of MP3 stereo audio data.


title: HD 85567: A Herbig B[e] star or an interacting B[e] binary

abstract:
  Context. HD 85567 is an enigmatic object exhibiting the B[e] phenomenon, i.e.
an infrared excess and forbidden emission lines in the optical. The object's
evolutionary status is uncertain and there are conflicting claims that it is
either a young stellar object or an evolved, interacting binary.
  Aims. To elucidate the reason for the B[e] behaviour of HD 85567, we have
observed it with the VLTI and AMBER.
  Methods. Our observations were conducted in the K-band with moderate spectral
resolution (R~1500, i.e. 200 km/s). The spectrum of HD 85567 exhibits Br gamma
and CO overtone bandhead emission. The interferometric data obtained consist of
spectrally dispersed visibilities, closure phases and differential phases
across these spectral features and the K-band continuum.
  Results. The closure phase observations do not reveal evidence of asymmetry.
The apparent size of HD 85567 in the K-band was determined by fitting the
visibilities with a ring model. The best fitting radius, 0.8 +/- 0.3 AU, is
relatively small making HD 85567 undersized in comparison to the
size-luminosity relationship based on YSOs of low and intermediate luminosity.
This has previously been found to be the case for luminous YSOs, and it has
been proposed that this is due to the presence of an optically thick gaseous
disc. We demonstrate that the differential phase observations over the CO
bandhead emission are indeed consistent with the presence of a compact (~1 AU)
gaseous disc interior to the dust sublimation radius.
  Conclusions. The observations reveal no sign of binarity. However, the data
do indicate the presence of a gaseous disc interior to the dust sublimation
radius. We conclude that the data are consistent with the hypothesis that HD
85567 is a YSO with an optically thick gaseous disc within a larger dust disc
that is being photo-evaporated from the outer edge.


title: New dates for the eras of the universe from the Planck data

abstract:
  Data from the Planck satellite imply new dates for the major eras of the
universe. The era of radiation ended 50,150 years after inflation and the era
of matter 10.31 billion years after inflation or 3.51 billion years ago.


title: From nuclear structure to neutron stars

abstract:
  Recent progress in quantum Monte Carlo with modern nucleon-nucleon
interactions have enabled the successful description of properties of light
nuclei and neutron-rich matter. As a demonstration, we show that the agreement
between theoretical calculations of the charge form factor of 12C and the
experimental data is excellent. Applying similar methods to isospin-asymmetric
systems allows one to describe neutrons confined in an external potential and
homogeneous neutron-rich matter. Of particular interest is the nuclear symmetry
energy, the energy cost of creating an isospin asymmetry. Combining these
advances with recent observations of neutron star masses and radii gives
insight into the equation of state of neutron-rich matter near and above the
saturation density. In particular, neutron star radius measurements constrain
the derivative of the symmetry energy.


title:
Improving Sparse Associative Memories by Escaping from Bogus Fixed
  Points

abstract:
  The Gripon-Berrou neural network (GBNN) is a recently invented recurrent
neural network embracing a LDPC-like sparse encoding setup which makes it
extremely resilient to noise and errors. A natural use of GBNN is as an
associative memory. There are two activation rules for the neuron dynamics,
namely sum-of-sum and sum-of-max. The latter outperforms the former in terms of
retrieval rate by a huge margin. In prior discussions and experiments, it is
believed that although sum-of-sum may lead the network to oscillate, sum-of-max
always converges to an ensemble of neuron cliques corresponding to previously
stored patterns. However, this is not entirely correct. In fact, sum-of-max
often converges to bogus fixed points where the ensemble only comprises a small
subset of the converged state. By taking advantage of this overlooked fact, we
can greatly improve the retrieval rate. We discuss this particular issue and
propose a number of heuristics to push sum-of-max beyond these bogus fixed
points. To tackle the problem directly and completely, a novel post-processing
algorithm is also developed and customized to the structure of GBNN.
Experimental results show that the new algorithm achieves a huge performance
boost in terms of both retrieval rate and run-time, compared to the standard
sum-of-max and all the other heuristics.


title: Mechanical fluidity of fully suspended biological cells

abstract:
  Mechanical characteristics of single biological cells are used to identify
and possibly leverage interesting differences among cells or cell populations.
Fluidity---hysteresivity normalized to the extremes of an elastic solid or a
viscous liquid---can be extracted from, and compared among, multiple
rheological measurements of cells: creep compliance vs. time, complex modulus
vs. frequency, and phase lag vs. frequency. With multiple strategies available
for acquisition of this nondimensional property, fluidity may serve as a useful
and robust parameter for distinguishing cell populations, and for understanding
the physical origins of deformability in soft matter. Here, for three disparate
eukaryotic cell types deformed in the suspended state via optical stretching,
we examine the dependence of fluidity on chemical and environmental influences
around a time scale of 1 s. We find that fluidity estimates are consistent in
the time and the frequency domains under a structural damping (power-law or
fractional derivative)model, but not under an equivalent-complexity
lumpedcomponent (spring-dashpot) model; the latter predicts spurious time
constants. Although fluidity is suppressed by chemical crosslinking, we find
that adenosine triphosphate (ATP) depletion in the cell does not measurably
alter the parameter, and thus conclude that active ATP-driven events are not a
crucial enabler of fluidity during linear viscoelastic deformation of a
suspended cell. Finally, by using the capacity of optical stretching to produce
near-instantaneous increases in cell temperature, we establish that fluidity
increases with temperature---now measured in a fully suspended, sortable cell
without the complicating factor of cell-substratum adhesion.


title: Graphs with Equal Chromatic Symmetric Functions

abstract:
  Stanley [9] introduced the chromatic symmetric function ${\bf X}_G$
associated to a simple graph $G$ as a generalization of the chromatic
polynomial of $G$. In this paper we present a novel technique to write ${\bf
X}_G$ as a linear combination of chromatic symmetric functions of smaller
graphs. We use this technique to give a sufficient condition for two graphs to
have the same chromatic symmetric function. We then construct an infinite
family of pairs of unicyclic graphs with the same chromatic symmetric function,
answering the question posed by Martin, Morin, and Wagner [7] of whether such a
pair exists. Finally, we approach the problem of whether it is possible to
determine a tree from its chromatic symmetric function. Working towards an
answer to this question, we give a classification theorem for single-centroid
trees in terms of data closely related to its chromatic symmetric function.


title: Tameness and Extending Frames

abstract:
  We combine two notions in AECs, tameness and good $\lambda$-frames, and show
that they together give a very well-behaved nonforking notion in all
cardinalities. This helps to fill a longstanding gap in classification theory
of tame AECs and increases the applicability of frames. Along the way, we prove
a complete stability transfer theorem and uniqueness of limit models in these
AECs.


title: Tree Codes and a Conjecture on Exponential Sums

abstract:
  We propose a new conjecture on some exponential sums. These particular sums
have not apparently been considered in the literature. Subject to the
conjecture we obtain the first effective construction of asymptotically good
tree codes. The available numerical evidence is consistent with the conjecture
and is sufficient to certify codes for significant-length communications.


title: Experimental Realization of a Quantum Ratchet Through Phase Modulation

abstract:
  We report on an experimental realization of unidirectional transporting
island structures in an otherwise chaotic phase space of the delta-kicked rotor
system. Using a Bose-Einstein Condensate as a source of ultracold atoms, we
employ asymmetric phase modulation in the kicks, with the narrow momentum
distribution of the atoms allowing us to address individual island structures.
We observe quantum ratchet behavior in this system, with clear directed
momentum current in the absence of a directional force, which we characterize
and connect to \epsilon-classical theory.


title: Robust PCA and MIC statistics of baryons in early mini-haloes

abstract:
  We present a novel approach, based on robust principal components analysis
(RPCA) and maximal information coefficient (MIC), to study the redshift
dependence of halo baryonic properties. Our data are composed of a set of
different physical quantities for primordial minihaloes: dark-matter mass
($M_{\mathrm{dm}}$), gas mass ($M_{\mathrm{gas}}$), stellar mass
($M_{\mathrm{star}}$), molecular fraction (${\mathrm{x_{mol}}}$), metallicity
($Z$), star formation rate (SFR) and temperature. We find that
$M_{\mathrm{dm}}$ and $M_{\mathrm{gas}}$ are dominant factors for variance,
particularly at high redshift. Nonetheless, with the emergence of the first
stars and subsequent feedback mechanisms, ${\mathrm{x_{mol}}}$, SFR and $Z$
start to have a more dominant role. Standard PCA gives three principal
components (PCs) capable to explain more than 97 per cent of the data variance
at any redshift (two PCs usually accounting for no less than 92 per cent),
whilst the first PC from the RPCA analysis explains no less than 84 per cent of
the total variance in the entire redshift range (with two PCs explaining $
\gtrsim 95$ per cent anytime). Our analysis also suggests that all the gaseous
properties have a stronger correlation with $M_{\mathrm{gas}}$ than with
$M_{\mathrm{dm}}$, while $M_{\mathrm{gas}}$ has a deeper correlation with
${\mathrm{x_{mol}}}$ than with $Z$ or SFR. This indicates the crucial role of
gas molecular content to initiate star formation and consequent metal pollution
from Population III and Population II/I regimes in primordial galaxies.
Finally, a comparison between MIC and Spearman correlation coefficient shows
that the former is a more reliable indicator when halo properties are weakly
correlated.


title: Modeling quasar accretion disc temperature profiles

abstract:
  Microlensing observations indicate that quasar accretion discs have
half-light radii larger than expected from standard theoretical predictions
based on quasar fluxes or black hole masses. Blackburne and colleagues have
also found a very weak wavelength dependence of these half-light radii. We
consider disc temperature profile models that might match these observations.
Nixon and colleagues have suggested that misaligned accretion discs around
spinning black holes will be disrupted at radii small enough for the
Lense-Thirring torque to overcome the disc's viscous torque. Gas in precessing
annuli torn off a disc will spread radially and intersect with the remaining
disc, heating the disc at potentially large radii. However, if the intersection
occurs at an angle of more than a degree or so, highly supersonic collisions
will shock-heat the gas to a Compton temperature of T~10^7 K, and the spectral
energy distributions (SEDs) of discs with such shock-heated regions are poor
fits to observations of quasar SEDs. Torn discs where heating occurs in
intermittent weak shocks that occur whenever the intersection angle reaches a
tenth of a degree pose less of a conflict with observations, but do not have
significantly larger half-light radii than standard discs. We also study two
phenomenological disc temperature profile models. We find that discs with a
temperature spike at relatively large radii and lowered temperatures at radii
inside the spike yield improved and acceptable fits to microlensing sizes in
most cases. Such temperature profiles could in principle occur in sub-Keplerian
discs partially supported by magnetic pressure. However, such discs overpredict
the fluxes from quasars studied with microlensing except in the limit of
negligible continuum emission from radii inside the temperature spike.


title:
Poincare-Birkhoff-Witt deformations of smash product algebras from Hopf
  actions on Koszul algebras

abstract:
  Let H be a Hopf algebra and let B be a Koszul H-module algebra. We provide
necessary and sufficient conditions for a filtered algebra to be a
Poincare-Birkhoff-Witt (PBW) deformation of the smash product algebra B#H. Many
examples of these deformations are given.


title: Kochen-Specker set with seven contexts

abstract:
  The Kochen-Specker (KS) theorem is a central result in quantum theory and has
applications in quantum information. Its proof requires several yes-no tests
that can be grouped in contexts or subsets of jointly measurable tests.
Arguably, the best measure of simplicity of a KS set is the number of contexts.
The smaller this number is, the smaller the number of experiments needed to
reveal the conflict between quantum theory and noncontextual theories and to
get a quantum vs classical outperformance. The original KS set had 132
contexts. Here we introduce a KS set with seven contexts and prove that this is
the simplest KS set that admits a symmetric parity proof.


title: Statistical significance of variables driving systematic variation

abstract:
  There are a number of well-established methods such as principal components
analysis (PCA) for automatically capturing systematic variation due to latent
variables in large-scale genomic data. PCA and related methods may directly
provide a quantitative characterization of a complex biological variable that
is otherwise difficult to precisely define or model. An unsolved problem in
this context is how to systematically identify the genomic variables that are
drivers of systematic variation captured by PCA. Principal components (and
other estimates of systematic variation) are directly constructed from the
genomic variables themselves, making measures of statistical significance
artificially inflated when using conventional methods due to over-fitting. We
introduce a new approach called the jackstraw that allows one to accurately
identify genomic variables that are statistically significantly associated with
any subset or linear combination of principal components (PCs). The proposed
method can greatly simplify complex significance testing problems encountered
in genomics and can be utilized to identify the genomic variables significantly
associated with latent variables. Using simulation, we demonstrate that our
method attains accurate measures of statistical significance over a range of
relevant scenarios. We consider yeast cell-cycle gene expression data, and show
that the proposed method can be used to straightforwardly identify
statistically significant genes that are cell-cycle regulated. We also analyze
gene expression data from post-trauma patients, allowing the gene expression
data to provide a molecularly-driven phenotype. We find a greater enrichment
for inflammatory-related gene sets compared to using a clinically defined
phenotype. The proposed method provides a useful bridge between large-scale
quantifications of systematic variation and gene-level significance analyses.


title:
Balanced networks of spiking neurons with spatially dependent recurrent
  connections

abstract:
  Networks of model neurons with balanced recurrent excitation and inhibition
produce irregular and asynchronous spiking activity. We extend the analysis of
balanced networks to include the known dependence of connection probability on
the spatial separation between neurons. In the continuum limit we derive that
stable, balanced firing rate solutions require that the spatial spread of
external inputs be broader than that of recurrent excitation, which in turn
must be broader than or equal to that of recurrent inhibition. For finite size
networks we investigate the pattern forming dynamics arising when balanced
conditions are not satisfied. The spatiotemporal dynamics of balanced networks
offer new challenges in the statistical mechanics of complex systems.


title: Dispersive probing of driven pseudo-spin dynamics in a gradient field

abstract:
  We have studied the coherent evolution of ultracold atomic rubidium clouds
subjected to a microwave field driving Rabi oscillations between the stretched
states of the F=1 and F=2 hyperfine levels. A phase winding of the two-level
system pseudo-spin vector is encountered for elongated samples of atoms exposed
to an axial magnetic field gradient and can be observed directly in
state-selective absorption imaging. When dispersively recording the
sample-integrated spin population during the Rabi drive, we observe a damped
oscillation directly related to the magnetic field gradient, which we quantify
using a simple dephasing model. By analyzing such dispersively acquired data
from millimeter sized atomic samples, we demonstrate that field gradients can
be determined with an accuracy of $\sim25$ nT/mm. The dispersive probing of
inhomogeneously broadened Rabi oscillations in prolate samples opens up a path
to gradiometry with bandwidths in the kilohertz domain.


title:
Exterior/interior problem for the circular means transform with
  applications to intravascular imaging

abstract:
  Exterior inverse problem for the circular means transform (CMT) arises in the
intravascular photoacoustic imaging (IVPA), in the intravascular ultrasound
imaging (IVUS), as well as in radar and sonar. The reduction of the IPVA to the
CMT is quite straightforward. As shown in the paper, in IVUS the circular means
can be recovered from measurements by solving a certain Volterra integral
equation. Thus, a tomography reconstruction in both modalities requires solving
the exterior problem for the CMT.
  Numerical solution of this problem usually is not attempted due to the
presence of "invisible" wavefronts, which results in severe instability of the
reconstruction. The novel inversion algorithm proposed in this paper yields a
stable partial reconstruction: it reproduces the "visible" part of the image
and blurs the "invisible" part. If the image contains little or no invisible
wavefronts (as frequently happens in the IVPA and IVUS) the reconstruction is
quantitatively accurate. The presented numerical simulations demonstrate the
feasibility of tomography-like reconstruction in these modalities.


title: Monomial, Gorenstein and Bass Orders

abstract:
  In this article we study a class of orders called {\it monomial orders} in a
central simple algebra over a non-Archimedean local field. Monomial orders are
easily represented and they may be also viewed as a direct generalization of
Eichler orders in quaternion algebras. A criterion for monomial orders to be
Gorenstein or to be Bass is given. It is shown that a monomial order is Bass if
and only if it is either a hereditary or an Eichler order of period two.


title: Dynamic Metrics of Heart Rate Variability

abstract:
  Numerous metrics of heart rate variability (HRV) have been described,
analyzed, and compared in the literature. However, they rarely cover the actual
metrics used in a class of HRV data acquisition devices - those designed
primarily to produce real-time metrics. This paper characterizes a class of
metrics that we term dynamic metrics. We also report the results of a pilot
study which compares one such dynamic metric, based on photoplethysmographic
data using a moving sampling window set to the length of an estimated breath
cycle (EBC), with established HRV metrics. The results show high correlation
coefficients between the dynamic EBC metrics and the established static SDNN
metric (standard deviation of Normal-to-Normal) based on electrocardiography.
These results demonstrate the usefulness of data acquisition devices designed
for real-time metrics.


title:
Herschel/PACS Survey of protoplanetary disks in Taurus/Auriga --
  Observations of [OI] and [CII], and far infrared continuum

abstract:
  The Herschel Space Observatory was used to observe ~ 120 pre-main-sequence
stars in Taurus as part of the GASPS Open Time Key project. PACS was used to
measure the continuum as well as several gas tracers such as [OI] 63 \mu m,
[OI] 145 \mu m, [CII] 158 \mu m, OH, H2O and CO. The strongest line seen is
[OI] at 63 \mu m. We find a clear correlation between the strength of the [OI]
63 \mu m line and the 63 \mu m continuum for disk sources. In outflow sources,
the line emission can be up to 20 times stronger than in disk sources,
suggesting that the line emission is dominated by the outflow. The tight
correlation seen for disk sources suggests that the emission arises from the
inner disk ($<$ 50 AU) and lower surface layers of the disk where the gas and
dust are coupled. The [OI] 63 \mu m is fainter in transitional stars than in
normal Class II disks. Simple SED models indicate that the dust responsible for
the continuum emission is colder in these disks, leading to weaker line
emission. [CII] 158 \mu m emission is only detected in strong outflow sources.
The observed line ratios of [OI] 63 \mu m to [OI] 145 \mu m are in the regime
where we are insensitive to the gas-to-dust ratio, neither can we discriminate
between shock or PDR emission. We detect no Class III object in [OI] 63 \mu m
and only three in continuum, at least one of which is a candidate debris disk.


title: A Herschel PACS survey of the dust and gas in Upper Scorpius disks

abstract:
  We present results of far-infrared photometric observations with Herschel
PACS of a sample of Upper Scorpius stars, with a detection rate of previously
known disk-bearing K and M stars at 70, 100, and 160 micron of 71%, 56%, and
50%, respectively. We fit power-law disk models to the spectral energy
distributions of K & M stars with infrared excesses, and have found that while
many disks extend in to the sublimation radius, the dust has settled to lower
scale heights than in disks of the less evolved Taurus-Auriga population, and
have much reduced dust masses. We also conducted Herschel PACS observations for
far-infrared line emission and JCMT observations for millimeter CO lines. Among
B and A stars, 0 of 5 debris disk hosts exhibit gas line emission, and among K
and M stars, only 2 of 14 dusty disk hosts are detected. The OI 63 micron and
CII 157 micron lines are detected toward [PZ99] J160421.7-213028 and [PBB2002]
J161420.3-190648, which were found in millimeter photometry to host two of the
most massive dust disks remaining in the region. Comparison of the OI line
emission and 63 micron continuum to that of Taurus sources suggests the
emission in the former source is dominated by the disk, while in the other
there is a significant contribution from a jet. The low dust masses found by
disk modeling and low number of gas line detections suggest that few stars in
Upper Scorpius retain sufficient quantities of material for giant planet
formation. By the age of Upper Scorpius, giant planet formation is essentially
complete.


title:
Selective Decoding in Associative Memories Based on Sparse-Clustered
  Networks

abstract:
  Associative memories are structures that can retrieve previously stored
information given a partial input pattern instead of an explicit address as in
indexed memories. A few hardware approaches have recently been introduced for a
new family of associative memories based on Sparse-Clustered Networks (SCN)
that show attractive features. These architectures are suitable for
implementations with low retrieval latency, but are limited to small networks
that store a few hundred data entries. In this paper, a new hardware
architecture of SCNs is proposed that features a new data-storage technique as
well as a method we refer to as Selective Decoding (SD-SCN). The SD-SCN has
been implemented using a similar FPGA used in the previous efforts and achieves
two orders of magnitude higher capacity, with no error-performance penalty but
with the cost of few extra clock cycles per data access.


title: The long bar as seen by the VVV Survey: II. Star counts

abstract:
  Context: There is still some debate about the presence and the morphological
properties of the long bar in the inner Galaxy.
  Aims: We investigate the morphological properties of the long Galactic bar
using the VVV survey extending star counts at least 3 mag deeper than 2MASS.
Our study covers the relatively unexplored negative longitudes of the Galactic
bar. We obtain a detailed description of the spatial distribution of star
counts towards the long Galactic bar as well as to measure its parameters.
  Methods: We performed star counts towards -20<l<0 deg., |b|< 2 deg. using
VVV, 2MASS, and GLIMPSE data. We applied an average interstellar extinction
correction. We also adjusted latitudinal profiles to obtain the centroid
variation and bar thickness.
  Results: We probe the structure of long Galactic bar, as well as its far edge
at l=-14 deg. The differences between counts with and without extinction
correction allow us to produce a crude extinction map showing regions with high
extinction, mainly beyond the end of long Galactic bar. The latitudinal
profiles show evidence of the centroid vertical variation with Galactic
longitude reaching a minimum at l=-13.8 deg. The bar has an inclination angle
43+/-5 deg with respect to the line Sun-Galactic center. In addition, we have
determined the bar parameters, such as thickness, length, and stellar
distribution.


title:
Generalized oscillator representations of the twisted
  Heisenberg-Virasoro algebra

abstract:
  In this paper, we first obtain a general result on sufficient conditions for
tensor product modules to be simple over an arbitrary Lie algebra. We classify
simple modules with a nice property over the infinite-dimensional Heisenberg
algebra ${\H}$, and then obtain a lot of simple modules over the twisted
Heisenberg-Virasoro algebra $\LL$ from generalized oscillator representations
of $\LL$ by extending these $\H$-modules. We give the necessary and sufficient
conditions for Whittaker modules over $\LL$ (in the more general setting) to be
simple. We use the "shifting technique" to determine the necessary and
sufficient conditions for the tensor products of highest weight modules and
modules of intermediate series over $\LL$ to be simple. At last we establish
the "embedding trick" to obtain a lot more simple $\LL$-modules.


title:
Willmore flow of surfaces in Riemannian spaces I:
  Concentration-compactness

abstract:
  In this paper we study the local regularity of closed surfaces immersed in a
Riemannian 3-manifold flowing by Willmore flow. We establish a pair of
concentration-compactness alternatives for the flow, giving a lower bound on
the maximal time of existence of the flow proportional to the concentration of
the curvature and area at initial time. The estimate from the first theorem is
purely in terms of the concentration of curvature at initial time but applies
only to ambient spaces with non-positive sectional curvature. The second
requires additional information on the concentration of area at initial time
but applies in more general background spaces. Applications of these results
shall appear in forthcoming work.


title: Small-Support Approximate Correlated Equilibria

abstract:
  We prove the existence of approximate correlated equilibrium of support size
polylogarithmic in the number of players and the number of actions per player.
In particular, using the probabilistic method, we show that there exists a
multiset of polylogarithmic size such that the uniform distribution over this
multiset forms an approximate correlated equilibrium. Along similar lines, we
establish the existence of approximate coarse correlated equilibrium with
logarithmic support.
  We complement these results by considering the computational complexity of
determining small-support approximate equilibria. We show that random sampling
can be used to efficiently determine an approximate coarse correlated
equilibrium with logarithmic support. But, such a tight result does not hold
for correlated equilibrium, i.e., sampling might generate an approximate
correlated equilibrium of support size \Omega(m) where m is the number of
actions per player. Finally, we show that finding an exact correlated
equilibrium with smallest possible support is NP-hard under Cook reductions,
even in the case of two-player zero-sum games.


title:
Diagnosis of the Wavelength Stability of a Mid-Infrared Free-Electron
  Laser

abstract:
  Wavelength stability of free-electron lasers (FELs) is one of the important
parameters for various applications. In this paper we describe two different
methods to diagnose the wavelength stability of a mid-infrared (MIR) FEL. The
first one is based on autocorrelation which is usually used to measure the
pulse duration, and the second one is based on frequency upconversion through
sum-frequency mixing (SFM).


title: Detection and classification from electromagnetic induction data

abstract:
  In this paper we introduce an efficient algorithm for identifying conductive
objects using induction data derived from eddy currents. Our method consists of
first extracting geometric features from the induction data and then matching
them to precomputed data for known objects from a given dictionary. The
matching step relies on fundamental properties of conductive polarization
tensors and new invariants introduced in this paper. A new shape identification
scheme is introduced and studied. We test it numerically in the presence of
measurement noise. Stability and resolution capabilities of the proposed
identification algorithm are quantified in numerical simulations.


title:
Senescent Cells in Growing Tumors: Population Dynamics and Cancer Stem
  Cells

abstract:
  Tumors are defined by their intense proliferation, but sometimes cancer cells
turn senescent and stop replicating. In the stochastic cancer model in which
all cells are tumorigenic, senescence is seen as the result of random
mutations, suggesting that it could represent a barrier to tumor growth. In the
hierarchical cancer model a subset of the cells, the cancer stem cells, divide
indefinitely while other cells eventually turn senescent. Here we formulate
cancer growth in mathematical terms and obtain predictions for the evolution of
senescence. We perform experiments in human melanoma cells which are compatible
with the hierarchical model and show that senescence is a reversible process
controlled by survivin. We conclude that enhancing senescence is unlikely to
provide a useful therapeutic strategy to fight cancer, unless the cancer stem
cells are specifically targeted


title:
Algorithm 950: Ncpol2sdpa---Sparse Semidefinite Programming Relaxations
  for Polynomial Optimization Problems of Noncommuting Variables

abstract:
  A hierarchy of semidefinite programming (SDP) relaxations approximates the
global optimum of polynomial optimization problems of noncommuting variables.
Generating the relaxation, however, is a computationally demanding task, and
only problems of commuting variables have efficient generators. We develop an
implementation for problems of noncommuting problems that creates the
relaxation to be solved by SDPA -- a high-performance solver that runs in a
distributed environment. We further exploit the inherent sparsity of
optimization problems in quantum physics to reduce the complexity of the
resulting relaxations. Constrained problems with a relaxation of order two may
contain up to a hundred variables. The implementation is available in Python.
The tool helps solve problems such as finding the ground state energy or
testing quantum correlations.


title: Correlations in Quantum Spin Systems from the Boundary Effect

abstract:
  We introduce the boundary effect on the ground state as an attribute of
general local spin systems that restricts the correlations in the ground state.
To this end, we introduce what we call a boundary effect function, which
characterises not only the boundary effect, but also the thermodynamic limit of
the ground state. We prove various aspects of the boundary effect function to
unfold its relationship to other attributes of the system such as a finite
spectral gap above the ground state, two-point correlation functions, and
entanglement entropies. In particular, it is proven that an exponentially
decaying boundary effect function implies the exponential clustering of
two-point correlation functions in arbitrary spatial dimension, the
entanglement area law in one dimension, and the logarithmically corrected area
law in higher dimension. It is also proven that gapped local spin systems with
nondegenerate ground states ordinarily fall into that class. In one dimension,
the area law can also result from a moderately decaying boundary effect
function, in which case the system is thermodynamically gapless.


title:
Do cancer cells undergo phenotypic switching? The case for imperfect
  cancer stem cell markers

abstract:
  The identification of cancer stem cells in vivo and in vitro relies on
specific surface markers that should allow to sort cancer cells in
phenotypically distinct subpopulations. Experiments report that sorted cancer
cell populations after some time tend to express again all the original
markers, leading to the hypothesis of phenotypic switching, according to which
cancer cells can transform stochastically into cancer stem cells. Here we
explore an alternative explanation based on the hypothesis that markers are not
perfect and are thus unable to identify all cancer stem cells. Our analysis is
based on a mathematical model for cancer cell proliferation that takes into
account phenotypic switching, imperfect markers and error in the sorting
process. Our conclusion is that the observation of reversible expression of
surface markers after sorting does not provide sufficient evidence in support
of phenotypic switching.


title:
Innate character and theory model about channel segregation in a sand
  mold steel ingot

abstract:
  The channel segregation is a severe casting defect in steel ingots. The
formation of channel segregation is generally attributed to the solute
partition and the interdendritic thermosolutal convection in the mushy zone. In
this article, the channel segregation in a steel ingot was carefully
characterized by detailed experimental observation. A different formation
mechanism for the channel segregation was revealed. In the mushy zone of the
ingot, large amount of separate MnS inclusions move laterally and upwards. Some
MnS inclusions will remain in the moving trace of inclusions. Such residual MnS
inclusions appear as large amount of separate MnS inclusion chains. In the
subsequent solid phase transition process, promoted by the MnS chains, ferrite
prefers to forms form the austenite near the MnS inclusions and shows as large
amount of separate ferrite chains. Large amount of ferrite chains align in a
strip-like zone, which results in so called channel segregation in
macro-etching. The physical model about the driving force for the MnS movement
is further theoretically analyzed. In the mushy zone, the interface tension
resultant applied on the MnS inclusions can act as the drive force for the
lateral movement of MnS inclusions. And the buoyance applied on the MnS
inclusions act as the drive force for the upwards movement.


title:
AQP1 Is Not Only a Water Channel: It Contributes to Cell Migration
  through Lin7/Beta-Catenin

abstract:
  Background: AQP1 belongs to aquaporins family, water-specific,
membrane-channel proteins expressed in diverse tissues. Recent papers showed
that during angiogenesis, AQP1 is expressed preferentially by microvessels,
favoring angiogenesis via the increase of permeability In particular, in AQP1
null mice, endothelial cell migration is impaired without altering their
proliferation or adhesion. Therefore, AQP1 has been proposed as a novel
promoter of tumor angiogenesis. Methods/Findings: Using targeted silencing of
AQP1 gene expression, an impairment in the organization of F-actin and a
reduced migration capacity was demonstrated in human endothelial and melanoma
cell lines. Interestingly, we showed, for the first time, that AQP1
co-immunoprecipitated with Lin-7. Lin7-GFP experiments confirmed
co-immunoprecipitation. In addition, the knock down of AQP1 decreased the level
of expression of Lin-7 and b-catenin and the inhibition of proteasome
contrasted partially such a decrease. Conclusions/Significance: All together,
our findings show that AQP1 plays a role inside the cells through
Lin-7/b-catenin interaction. Such a role of AQP1 is the same in human melanoma
and endothelial cells, suggesting that AQP1 plays a global physiological role.
A model is presented.


title:
Microsegregation and dendritic growth mode of Al-5wt%Cu alloy based on
  non-equilibrium mush zone model

abstract:
  The microsegregation and dendritic growth mode of Al-5wt%Cu alloy was
investigated. In the early solidification stage, the crystal growth mode of
interrupted growth and periodic boundary trapping will happen, which results in
the segregationless dendritic grains. Microsegregation only exists at the final
solidification stage with extremely tiny residual melt fraction. In the tiny
residual melt zone, the diffusion of solute from the enriched boundary layer to
the residual melt and the convergence of enriched boundaries produce the final
microsegregation.


title:
CXCR6, a Newly Defined Biomarker of Tissue-Specific Stem Cell Asymmetric
  Self-Renewal, Identifies More Aggressive Human Melanoma Cancer Stem Cells

abstract:
  Background: A fundamental problem in cancer research is identifying the cell
type that is capable of sustaining neoplastic growth and its origin from normal
tissue cells. Recent investigations of a variety of tumor types have shown that
phenotypically identifiable and isolable subfractions of cells possess the
tumor-forming ability. In the present paper, using two lineage-related human
melanoma cell lines, primary melanoma line IGR39 and its metastatic derivative
line IGR37, two main observations are reported. The first one is the first
phenotypic evidence to support the origin of melanoma cancer stem cells (CSCs)
from mutated tissue-specific stem cells; and the second one is the
identification of a more aggressive subpopulation of CSCs in melanoma that are
CXCR6+. Conclusions/Significance: The association of a more aggressive tumor
phenotype with asymmetric self-renewal phenotype reveals a previously
unrecognized aspect of tumor cell physiology. Namely, the retention of some
tissue-specific stem cell attributes, like the ability to asymmetrically
self-renew, impacts the natural history of human tumor development. Knowledge
of this new aspect of tumor development and progression may provide new targets
for cancer prevention and treatment.


title: Angular Momentum of Phonons and Einstein-de Haas Effect

abstract:
  We study angular momentum of phonons in a magnetic crystal. In the presence
of a spin-phonon interaction, we obtain a nonzero angular momentum of phonons,
which is an odd function of magnetization. At zero temperature, phonon has a
zero-point angular momentum besides a zero-point energy. With increasing
temperature, the total phonon angular momentum diminishes and approaches to
zero in the classical limit. The nonzero phonon angular momentum can have a
significant impact on the Einstein-de Haas effect. To obtain the change of
angular momentum of electrons, the change of phonon angular momentum needs to
be subtracted from the opposite change of lattice angular momentum.
Furthermore, the finding of phonon angular momentum gives a potential method to
study the spin-phonon interaction. Possible experiments on phonon angular
momentum are also discussed.

categories: cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.stat-mech quant-ph


title: Growth and form of melanoma cell colonies

abstract:
  We study the statistical properties of melanoma cell colonies grown in vitro
by analyzing the results of crystal violet assays at different concentrations
of initial plated cells and for different growth times. The distribution of
colony sizes is described well by a continuous time branching process. To
characterize the shape fluctuations of the colonies, we compute the
distribution of eccentricities. The experimental results are compared with
numerical results for models of random division of elastic cells, showing that
experimental results are best reproduced by restricting cell division to the
outer rim of the colony. Our results serve to illustrate the wealth of
information that can be extracted by a standard experimental method such as the
crystal violet assay.


title:
On sparse interpolation and the design of deterministic interpolation
  points

abstract:
  In this paper, we build up a framework for sparse interpolation. We first
investigate the theoretical limit of the number of unisolvent points for sparse
interpolation under a general setting and try to answer some basic questions of
this topic. We also explore the relation between classical interpolation and
sparse interpolation. We second consider the design of the interpolation points
for the $s$-sparse functions in high dimensional Chebyshev bases, for which the
possible applications include uncertainty quantification, numerically solving
stochastic or parametric PDEs and compressed sensing. Unlike the traditional
random sampling method, we present in this paper a deterministic method to
produce the interpolation points, and show its performance with $\ell_1$
minimization by analyzing the mutual incoherence of the interpolation matrix.
Numerical experiments show that the deterministic points have a similar
performance with that of the random points.


title:
Theoretical Origin of CP Violation in a Special FCNC-Free 2HDM with
  $S_N$ Symmetries

abstract:
  In this manuscript, a way solves the FCNC problem in 2HDM radically and leads
to CP violation explicitly is demonstrated. The derivation starts from a most
general $3 \times 3$ mass matrix $M$ containing eighteen parameters, which
applies to all fermion types, and then reduces the number of parameters down to
five with a Hermitian condition modified in this manuscript between the real
part and imaginary part of $M$. All matrix pairs thus derived will be
diagonalized simultaneously by a same $U$ matrix which means FCNCs won't appear
at tree-level anymore. Subsequently, an assumption of $A=A_1=A_2=A_3$ is
imposed and four special solutions are thus found which reveal $S_3$ and $S_2$
symmetries among fermion generations respectively. Consequently, as a
by-product of solving the FCNC problem, complex CKM matrices appear if the
symmetries were assigned to up- and down-type quarks suitably. Unfortunately,
CKM elements thus derived are very different to the experimentally detected
values. The CP strength of this model, estimated by the Jarlskog invariant, is
four orders higher than the one predicted by the standard model. This
difference is in fact reasonable since we don't see any such symmetries in our
present universe. However, if they had appeared in some early stages of our
universe, such a strong CP strength may provide a way to account for at least
part of the discrepancy between the observed BAU and that predicted by the
standard model.


title: Cofiniteness of local cohomology modules for ideals of dimension one

abstract:
  Let $R$ denote a commutative Noetherian (not necessarily local) ring, $M$ an
arbitrary $R$-module and $I$ an ideal of $R$ of dimension one. It is shown that
the $R$-module $\Ext^i_R(R/I,M)$ is finitely generated (resp. weakly Laskerian)
for all $i\leq {\rm cd}(I,M)+1$ if and only if the local cohomology module
$H^i_I(M)$ is $I$-cofinite (resp. $I$-weakly cofinite) for all $i$. Also, we
show that when $I$ is an arbitrary ideal and $M$ is finitely generated module
such that the $R$-module $H^i_I(M)$ is weakly Laskerian for all $i\leq t-1$,
then $H^i_I(M)$ is $I$-cofinite for all $i\leq t-1$ and for any minimax
submodule $K$ of $H^{t}_I(M)$, the $R$-modules $\Hom_R(R/I, H^{t}_I(M)/K)$ and
$\Ext^{1}_R(R/I, H^{t}_I(M)/K)$ are finitely generated, where $t$ is a
non-negative integer. This generalizes the main result of Bahmanpour-Naghipour
\cite{BN} and Brodmann and Lashgari \cite{BL}.


title:
Discovery of a New Member of the Inner Oort Cloud from The Next
  Generation Virgo Cluster Survey

abstract:
  We report the discovery of 2010 GB$_{174}$, a likely new member of the Inner
Oort Cloud (IOC). 2010 GB$_{174}$ is one of 91 Trans Neptunian Objects (TNOs)
and Centaurs discovered in a 76 deg$^2$ contiguous region imaged as part of the
Next Generation Virgo Cluster Survey (NGVS) --- a moderate ecliptic latitude
survey reaching a mean limiting magnitude of $g^\prime \simeq 25.5$ --- using
MegaPrime on the 3.6m Canada France Hawaii Telescope. 2010 GB$_{174}$ is found
to have an orbit with semi-major axis $a\simeq350.8$ AU, inclination $i \simeq
21.6^\circ$ and pericentre $q\sim48.5$ AU. This is the second largest
perihelion distance among known solar system objects. Based on the sky coverage
and depth of the NGVS, we estimate the number of IOC members with sizes larger
than 300 km ($H_V \le 6.2$ mag) to be $\simeq 11\,000$. A comparison of the
detection rate from the NGVS and the PDSSS (a characterized survey that
`re-discovered' the IOC object Sedna) gives, for an assumed a power-law LF for
IOC objects, a slope of $\alpha \simeq 0.7 \pm 0.2$, with only two detections
in this region this slope estimate is highly uncertain.


title: Add-drop system for Kerr bistable memory in silicon nitride microrings

abstract:
  We numerically studied the required conditions for achieving a memory
operation based on Kerr bistability in the presence of the thermo-optic effect
in silicon nitride microring cavity systems. By comparing a side-coupled system
and an add-drop system, we found that the latter is needed to realize obtain
Kerr bistable operation. In addition, we show the coupling coefficient range in
which the memory operation does not suffer from the thermo-optic effect.


title: Socle finiteness of local cohomology modules and Gorenstein ideals

abstract:
  The purpose of this paper is to give some equivalent conditions to the socle
and Bass numbers' conjectures which raised by C. Huneke in (Problems on local
cohomology, Free resolutions in commutative algebra and algebraic geometry,
Res. Notes Math. 1992, pp. 93-108). In addition, some results about certain
Gorenstein ideals are included.


title: A new characterization of Cohen-Macaulay rings

abstract:
  The purpose of this article is to provide a new characterization of
Cohen-Macaulay local rings. As a consequence we deduce that a local
(Noetherian) ring $R$ is Gorenstein if and only if every parameter ideal of $R$
is irreducible.


title:
Discriminant of the ordinary transversal singularity type. The global
  equivalence class

abstract:
  Consider a space X with the singular locus of positive dimension, Z=Sing(X).
Suppose both Z and X are locally complete intersections at each point. The
transversal type of X along Z is generically constant but at some points of Z
it degenerates. In the previous work we have introduced (locally) the
discriminant of the transversal type, a subscheme of Z, that reflects these
degenerations whenever the generic transversal type is "ordinary". We have
established the basic local properties of the discriminant.
  In the current paper we consider the global case. We compute the equivalence
class of the discriminant in the Picard group, Pic(Z). If $X$ is a
hypersurface, the discriminant is naturally stratified by the singularities of
fibres in the projectivized normal cone $\mathbb{P}$N$_{X/Z}$.
  In this case (under some additional assumptions) we compute the classes of
low codimension strata in the Chow group, A$^2$(Z).
  As immediate applications, we (re)derive the multi-degrees of the classical
discriminant of projective complete intersections and bound the jumps of
multiplicity of X along Z (when the singular locus is one-dimensional).


title: Baroclinic Instability in Differentially Rotating Stars

abstract:
  A linear analysis of baroclinic instability in a stellar radiation zone with
radial differential rotation is performed. The instability onsets at a very
small rotation inhomogeneity. There are two families of unstable disturbances
corresponding to Rossby waves and internal gravity waves. The instability is
dynamical: its growth time of several thousand rotation periods is short
compared to the stellar evolution time. A decrease in thermal conductivity
amplifies the instability. Unstable disturbances possess kinetic helicity thus
indicating the possibility of magnetic field generation by the turbulence
resulting from the instability.


title:
Time-dependent nonextensivity arising from the rotational evolution of
  solar-type stars

abstract:
  Nonextensive formalism is a generalization of the Boltzmann-Gibbs statistics.
In this formalism the entropic index q is a quantity characterizing the degree
of nonextensivity, and is interpreted as a parameter of long-memory or
long-range interactions between the components of the system. Since its
proposition in 1988, this formalism has been applied to investigate a wide
variety of natural phenomena. In stellar astrophysics, theoretical distribution
function based on nonextensive formalism (q-distributions) has been
successfully applied to reproduce the distribution of stellar radial and
rotational velocity data. In this paper, we investigate the time variation of
the entropic index q obtained from the distribution of rotation, Vsini, for a
sample of 254 rotational data for solar-type stars from 11 open clusters aged
between 35.5Myr and 2.6Gyr. As a result, we have found an anti-correlation
between the entropic index q and the age of clusters, and that the distribution
of rotation Vsini for these stars becomes extensive for an age greater than
about 170Myr. Assuming that the parameter q is associated with long-memory
effects, we suggest that the memory of the initial angular momentum of
solar-type stars can be scaled by the entropic index q. We also propose a
physical link between the parameter q and the magnetic braking of stellar
rotation.


title: Quintasymptotic sequences over an ideal and quintasymptotic cograde

abstract:
  Let $I$ denote an ideal of a Noetherian ring $R$. The purpose of this article
is to introduce the concepts of quintasymptotic sequences over $I$ and
quintasymptotic cograde of $I$, and it is shown that they play a role analogous
to quintessential sequences over $I$ and quintessential cograde of $I$, given
in \cite{Ra1}. Also, we show that, if $R$ is local, then the quintasymptotic
cograde of $I$ is unambiguously defined and behaves well when passing to
certain related local rings. Finally, we use this cograde to characterize of
two classes of local rings.


title:
Experimentally demonstrated an unidirectional electromagnetic cloak
  designed by topology optimization

abstract:
  Electromagnetic invisible devices usually designed by transformation optics
are rather complicated in material parameters and not suitable for general
applications. Recently a topology optimized cloak based on level-set method was
proposed to realize nearly perfect cloaking by Fujii et al [Appl. Phys. Lett.
102, 251106 (2013)]. In this work we experimentally implemented this idea and
fabricated a unidirectional cloak with a relative large invisible region made
of single dielectric material. Good cloaking performance was verified through
measurement which consists very well with numerical simulation. The advantages
and disadvantages of this optimization method are also discussed.


title:
Testing Lambda and the Limits of Cosmography with the Union2.1 Supernova
  Compilation

abstract:
  We present a cosmographic study designed to test the simplest type of
accelerating cosmology: a flat universe with matter and a cosmological constant
($\Lambda$). Hubble series expansions are fit to the SCP Union2.1 supernova
data set to estimate the Hubble Constant ($H_{0}$), the deceleration parameter
($q_{0}$), and the jerk parameter ($j_{0}$). Flat $\Lambda$CDM models always
require $j_{0} = 1$, providing a single-parameter test of the entire paradigm.
Because of convergence issues for $z \gtrsim 1$, we focus on expansions using
the newer redshift variable $y$, and to estimate the effects of "model-building
uncertainties" -- the dependence of the output results upon the fitting
function and parameters used -- we perform fits using five different distance
indicator functions, and four different polynomial orders. We find that one
cannot yet use the supernova data to reliably obtain more than four
cosmological parameters, and that cosmographic estimates of $j_{0}$ remain
dominated by model-building uncertainties, in conjunction with statistical and
other error sources. While $j_{0} = 1$ remains consistent with Union2.1, the
most restrictive bound that we can place is $j_{0} \sim [-7.6,8.5]$. To test
the future prospects of cosmography with new standard candle data, ensembles of
mock supernova data sets are created, and it is found that the best way to
reduce model-building uncertainties on lower-order Hubble parameters (such as
$\{H_{0}, q_{0}, j_{0} \}$) is by limiting the redshift range of the data. Thus
more and better $z \lesssim 1$ data, not higher-redshift data, is needed to
sharpen cosmographic tests of flat $\Lambda$CDM.


title:
Second Harmonic Generation in Photonic Crystal Cavities in
  (111)-Oriented GaAs

abstract:
  We demonstrate second harmonic generation at telecommunications wavelengths
in L3 photonic crystal cavities in (111)-oriented GaAs. The second harmonic
power from photonic crystal cavities fabricated in (111)-oriented GaAs is
significantly increased compared to those fabricated in conventional
(001)-oriented GaAs.


title: Statistical Mechanics of Multistability in Microscopic Shells

abstract:
  Unlike macroscopic multistable mechanical systems such as snap bracelets or
elastic shells that must be physically manipulated into various conformations,
microscopic systems can undergo spontaneous conformation switching between
multistable states due to thermal fluctuations. Here we investigate the
statistical mechanics of shape transitions in small elastic elliptical plates
and shells driven by noise. By assuming that the effects of edges are small,
which we justify exactly for plates and shells with a lenticular section, we
decompose the shapes into a few geometric modes whose dynamics are easy to
follow. We use Monte Carlo simulations to characterize the shape transitions
between conformation minima as a function of noise strength, and corroborate
our results using a Fokker-Planck formalism to study the stationary
distribution and the mean first passage time problem. Our results are
applicable to objects such as such as graphene flakes or protein
{\beta}-sheets, where fluctuations, geometry and finite size effects are
important.


title:
Multi-Wavelength Studies of Spectacular Ram Pressure Stripping of a
  Galaxy. II. Star Formation in the Tail

abstract:
  With multiband photometric data in public archives, we detected four
intracluster star-forming regions in the Virgo cluster. Two of them were at a
projected distance of 35 kpc away from NGC4388, and the other two were 66 kpc
away. Our new spectroscopic observation revealed that their recession
velocities were comparable to the ram-pressure-stripped tail of NGC4388 and
confirmed their association. The stellar mass of the star-forming regions
ranged from 10^4 - 10^4.5 M_sun except for that of the faintest one which would
be <10^3 M_sun. The metallicity was comparable to the solar abundance, and the
age of the stars was ~ 10^6.8 years. Their young stellar age meant that the
star formation should have started after the gas was stripped from NGC4388.
This implied in situ condensation of the stripped gas. We also found that two
star-forming regions lay near the leading edge of a filamentary dark cloud. The
extinction of the filament was smaller than that derived from the Balmer
decrement of the star-forming regions. It implied that the dust in the filament
would be locally dense around the star-forming regions.


title: The Minimization of the Number of Colors is Different at p=11

abstract:
  In this article we present the following new fact for prime p=11. For knots
6_2 and 7_2, mincol_{11} 6_2 = 5 = mincol_{11} 7_2, along with the following
feature. There is a pair of diagrams, one for 6_2 and the other one for 7_2,
each of them admitting only non-trivial 11-colorings using 5 colors, but
neither of them admitting being colored with the sets of 5 colors that color
the other one. This is in full contrast with the behavior exhibited by links
admitting non-trivial p-colorings over the smaller primes, p=2, 3, 5 or 7.
  We also prove results concerning obstructions to the minimization of colors
over generic odd moduli. We apply these to find the right colors to eliminate
from non-trivial colorings. We thus prove that 5 is the minimum number of
colors for each knot of prime determinant 11 or 13 from Rolfsen's table.


title:
Gradient Flow for the Willmore Functional in Riemannian Manifolds of
  bounded Geometry

abstract:
  We consider the $L^2$ gradient flow for the Willmore functional in Riemannian
manifolds of bounded geometry. In the euclidean case E.\;Kuwert and
R.\;Sch\"atzle [\textsl{Gradient flow for the Willmore functional,} Comm. Anal.
Geom., 10: 307-339, 2002] established a lower bound of a smooth solution of
such a flow, which depends only on how much the curvature of the initial
surface is concentrated in space. In a second joint work [\textsl{The Willmore
flow with small initial energy,} J.\;Differential Geom., 57: 409-441, 2001] the
aforementioned authors proved that a suitable blow-up converges to a nonumbilic
(compact or noncompact) Willmore surface. In the lecture notes of the first
author [\textsl{The Willmore Functional,} unpublished lecture notes, ETH
Z\"urich, 2007] the blow-up analysis was refined. In the present work we intend
to generalize the results mentioned above to the Riemannian setting.


title:
Brain MRI Segmentation with Fast and Globally Convex Multiphase Active
  Contours

abstract:
  Multiphase active contour based models are useful in identifying multiple
regions with different characteristics such as the mean values of regions. This
is relevant in brain magnetic resonance images (MRIs), allowing the
differentiation of white matter against gray matter. We consider a well defined
globally convex formulation of Vese and Chan multiphase active contour model
for segmenting brain MRI images. A well-established theory and an efficient
dual minimization scheme are thoroughly described which guarantees optimal
solutions and provides stable segmentations. Moreover, under the dual
minimization implementation our model perfectly describes disjoint regions by
avoiding local minima solutions. Experimental results indicate that the
proposed approach provides better accuracy than other related multiphase active
contour algorithms even under severe noise, intensity inhomogeneities, and
partial volume effects.


title: Outer trapped surfaces are dense near MOTSs

abstract:
  We show that any vacuum initial data set containing a marginally outer
trapped surface S and satisfying a "no KIDs" condition can be perturbed near S
so that S becomes strictly outer trapped in the new vacuum initial data set.
This, together with the results in [9], gives a precise sense in which generic
initial data containing marginally outer trapped surfaces lead to geodesically
incomplete spacetimes.


title: Data Grid Concepts for Data Security in Distributed Computing

abstract:
  Data grid is a distributed computing architecture that integrates a large
number of data and computing resources into a single virtual data management
system. It enables the sharing and coordinated use of data from various
resources and provides various services to fit the needs of high performance
distributed and data-intensive computing. Here data partitioning and dynamic
replication in data grid are considered. In which security and access
performance of a system are efficient. There are several important requirements
for data grids, including information survivability, security, and access
performance. More specifically, the investigation is the problem of optimal
allocation of sensitive data objects that are partitioned by using secret
sharing scheme or erasure coding scheme and replicated. DATA PARTITIONING is
known as the single data can be divided into multiple objects. REPLICATION is
known as process of sharing information. storing same data in multiple systems.
Replication techniques are frequently used to improve data availability. Single
point failure does not affect this system. Where the data will be secured.


title: Local algebras with radical cubic zero are PCM-free

abstract:
  An artin algebra is said to be PCM-free if every finitely generated
Gorenstein projective module with a projective submodule is projective. In this
paper, we show that artin local algebras with radical cubic zero are PCM-free.


title:
Exact solution for Bloch oscillations of a simple charge-density-wave
  insulator

abstract:
  Charge-density-wave systems have a static modulation of the electronic charge
at low temperatures when they enter an ordered state. While they have been
studied for decades in equilibrium, it is only recently that they have been
examined in nonequilibrium with time-resolved studies. Here, we present the
exact solution for the nonequilibrium response of electrons (in the simplest
model for a charge density wave) when the system is placed under a strong DC
electric field. This allows us to examine the formation of driven Bloch
oscillations and how the presence of a current modifies the nonequilibrium
density of states.


title:
Validity of Fourier's law in one-dimensional momentum-conserving
  lattices with asymmetric interparticle interactions

abstract:
  We have numerically studied heat conduction in a few one-dimensional
momentum-conserving lattices with asymmetric interparticle interactions by the
nonequilibrium heat bath method, the equilibrium Green-Kubo method, and the
heat current power spectra analysis. Very strong finite-size effects are
clearly observed. Such effects make the heat conduction obey a Fourier-like law
in a wide range of lattice lengths. However, in yet longer lattice lengths, the
heat conductivity regains its power-law divergence. Therefore the power-law
divergence of the heat conductivity in the thermodynamic limit is verified, as
is expected by many existing theories.