title: Local quantum information dynamics

abstract:
  In this paper we: 1) show how the smooth geometry of spaces of normal quantum
states over W*-algebras (generalised spaces of density matrices) may be used to
substantially enrich the description of quantum dynamics in the algebraic and
path integral approaches; 2) discuss a framework for postquantum information
theories, such that quantum mechanical linearity holds only locally, while the
nonlocal multi-user dynamics exhibits some similarity with general relativity.
In the algebraic setting, we propose a method of incorporating nonlinear
Poisson and relative entropic local dynamics, as well as local gauge and local
source structures, into an effective description of local temporal evolution of
quantum states by using fibrewise perturbations of liouvilleans in the fibre
bundle of Hilbert spaces. In the path integral setting, we incorporate local
geometry by a generalisation of the Daubechies--Klauder coherent state phase
space propagator formula. Finally, we discuss the role of Bregman relative
entropy in the Jaynes--Mitchell--Favretti renormalisation scheme. As a result,
we show that: 1) the propagation of quantum particles (in Wigner's sense) can
be naturally explained as a free fall along the trajectories locally minimising
the quantum relative entropy; 2) the contribution of particular trajectories to
the global path integral is weighted by the local quantum entropic prior,
measuring user's lack of information; 3) the presence of nonlinear quantum
control variables results in the change of the curvature of the global quantum
state space; 4) the behaviour of zero-point energy under renormalisation of
local entropic dynamics is maintained by local redefinition of information mass
(prior), which encodes the curvature change. This leads us to a new framework
for nonequilibrium quantum statistical mechanics based on quantum Orlicz
spaces, quantum Bregman distances and Banach Lie algebras.


title: Pseudo-Hermitian systems, involutive symmetries and pseudofermions

abstract:
  We have briefly analyzed the existence of the pseudofermionic structure of
multilevel pseudo-Hermitian systems with odd time-reversal and higher order
involutive symmetries. We have shown that 2N-level Hamiltonians with N-order
eigenvalue degeneracy can be represented in the oscillator-like form in terms
of pseudofermionic creation and annihilation operators for both real and
complex eigenvalues. The example of most general four-level traceless
Hamiltonian with odd time-reversal symmetry, which is an extension of the SO(5)
Hermitian Hamiltonian, is considered in greater and explicit detail.


title:
Concentrated Differential Privacy: Simplifications, Extensions, and
  Lower Bounds

abstract:
  "Concentrated differential privacy" was recently introduced by Dwork and
Rothblum as a relaxation of differential privacy, which permits sharper
analyses of many privacy-preserving computations. We present an alternative
formulation of the concept of concentrated differential privacy in terms of the
Renyi divergence between the distributions obtained by running an algorithm on
neighboring inputs. With this reformulation in hand, we prove sharper
quantitative results, establish lower bounds, and raise a few new questions. We
also unify this approach with approximate differential privacy by giving an
appropriate definition of "approximate concentrated differential privacy."


title: Shape from Mixed Polarization

abstract:
  Shape from Polarization (SfP) estimates surface normals using photos captured
at different polarizer rotations. Fundamentally, the SfP model assumes that
light is reflected either diffusely or specularly. However, this model is not
valid for many real-world surfaces exhibiting a mixture of diffuse and specular
properties. To address this challenge, previous methods have used a sequential
solution: first, use an existing algorithm to separate the scene into diffuse
and specular components, then apply the appropriate SfP model. In this paper,
we propose a new method that jointly uses viewpoint and polarization data to
holistically separate diffuse and specular components, recover refractive
index, and ultimately recover 3D shape. By involving the physics of
polarization in the separation process, we demonstrate competitive results with
a benchmark method, while recovering additional information (e.g. refractive
index).


title:
Effect of water vapor on the performance of glass RPCs in avalanche mode
  operation

abstract:
  We studied the effect of water vapor on the performance of glass Resistive
Plate Chambers (RPCs) in the avalanche mode operation. Controlled and
calibrated amount of water vapor was added to the RPC gas mixture that has
C$_2$H$_2$F$_4$ as the major component. The deterioration in the performance of
RPC was observed while operating with wet gas and recovered after switching to
standard gas.


title:
Optimal Reliability in Energy Harvesting Industrial Wireless Sensor
  Networks

abstract:
  For Industrial Wireless Sensor Networks, it is essential to reliably sense
and deliver the environmental data on time to avoid system malfunction. While
energy harvesting is a promising technique to extend the lifetime of sensor
nodes, it also brings new challenges for system reliability due to the
stochastic nature of the harvested energy. In this paper, we investigate the
optimal energy management policy to minimize the weighted packet loss rate
under delay constraint, where the packet loss rate considers the lost packets
both during the sensing and delivering processes. We show that the above energy
management problem can be modeled as an infinite horizon average reward
constraint Markov decision problem. In order to address the well-known curse of
dimensionality problem and facilitate distributed implementation, we utilize
the linear value approximation technique. Moreover, we apply stochastic online
learning with post-decision state to deal with the lack of knowledge of the
underlying stochastic processes. A distributed energy allocation algorithm with
water-filling structure and a scheduling algorithm by auction mechanism are
obtained. Experimental results show that the proposed algorithm achieves nearly
the same performance as the optimal offline value iteration algorithm while
requiring much less computation complexity and signaling overhead, and
outperforms various existing baseline algorithms.


title: Laser impact on a drop

abstract:
  The impact of a laser pulse on a highly absorbing liquid drop can lead to a
violent response: the drop is accelerated, strongly deforms, and eventually
fragments. Shock waves, the ejection of matter, and even plasma formation can
accompany this process ...


title: APFELgrid: a high performance tool for parton density determinations

abstract:
  We present a new software package designed to reduce the computational burden
of hadron collider measurements in Parton Distribution Function (PDF) fits. The
APFELgrid package converts interpolated weight tables provided by APPLgrid
files into a more efficient format for PDF fitting by the combination with PDF
and $\alpha_s$ evolution factors provided by APFEL. This combination
significantly reduces the number of operations required to perform the
calculation of hadronic observables in PDF fits and simplifies the structure of
the calculation into a readily optimised scalar product. We demonstrate that
our technique can lead to a substantial speed improvement when compared to
existing methods without any reduction in numerical accuracy.


title:
Plasmoids in relativistic reconnection, from birth to adulthood: first
  they grow, then they go

abstract:
  Blobs, or quasi-spherical emission regions containing relativistic particles
and magnetic fields, are often assumed ad hoc in emission models of
relativistic astrophysical jets, yet their physical origin is still not well
understood. Here, we employ a suite of large-scale two-dimensional
particle-in-cell simulations in electron-positron plasmas to demonstrate that
relativistic magnetic reconnection can naturally account for the formation of
quasi-spherical plasmoids filled with high-energy particles and magnetic
fields. Our simulations extend to unprecedentedly long temporal and spatial
scales, so we can capture the asymptotic physics independently of the initial
setup. We characterize the properties of the plasmoids that are continuously
generated as a self-consistent by-product of the reconnection process: they are
in rough energy equipartition between particles and magnetic fields; the upper
energy cutoff of the plasmoid particle spectrum is proportional to the plasmoid
width w, corresponding to a Larmor radius ~0.2 w; the plasmoids grow in size at
~0.1 of the speed of light, with most of the growth happening while they are
still non-relativistic (first they grow); their growth is suppressed once they
get accelerated to relativistic speeds by the field line tension, up to the
Alfven speed (then they go). The largest plasmoids, whose typical recurrence
interval is ~2.5 L/c, reach a characteristic size w ~ 0.2 L independently of
the system length L, they have nearly isotropic particle distributions and they
contain the highest energy particles, whose Larmor radius is ~0.03 L. The
latter can be regarded as the Hillas criterion for relativistic reconnection.
We briefly discuss the implications of our results for the high-energy emission
from relativistic jets and pulsar winds.


title:
A to Z of the Muon Anomalous Magnetic Moment in the MSSM with Pati-Salam
  at the GUT scale

abstract:
  We analyse the low energy predictions of the minimal supersymmetric standard
model (MSSM) arising from a GUT scale Pati-Salam gauge group further
constrained by an $A_4 \times Z_5$ family symmetry, resulting in four soft
scalar masses at the GUT scale: one left-handed soft mass $m_0$ and three
right-handed soft masses $m_1,m_2,m_3$, one for each generation. We demonstrate
that this model, which was initially developed to describe the neutrino sector,
can explain collider and non-collider measurements such as the dark matter
relic density, the Higgs boson mass and, in particular, the anomalous magnetic
moment of the muon $(g-2)_\mu$. Since about two decades, $(g-2)_\mu$ suffers a
puzzling about 3$\,\sigma$ excess of the experimentally measured value over the
theoretical prediction, which our model is able to fully resolve. As the
consequence of this resolution, our model predicts specific regions of the
parameter space with the specific properties including light smuons and
neutralinos, which could also potentially explain di-lepton excesses observed
by CMS and ATLAS.


title:
Signatures of Majorana Kramers pairs in superconductor-Luttinger liquid
  and superconductor-quantum dot-normal lead junctions

abstract:
  Time-reversal invariant topological superconductors are characterized by the
presence of Majorana Kramers pairs localized at defects. One of the transport
signatures of Majorana Kramers pairs is the quantized differential conductance
of $4e^2/h$ when such a one-dimensional superconductor is coupled to a
normal-metal lead. The resonant Andreev reflection, responsible for this
phenomenon, can be understood as the boundary condition change for lead
electrons at low energies. In this paper, we study the stability of the Andreev
reflection fixed point with respect to electron-electron interactions in the
Luttinger liquid. We first calculate the phase diagram for the Luttinger
liquid-Majorana Kramers pair junction and show that its low-energy properties
are determined by Andreev reflection scattering processes in the spin-triplet
channel, i.e. the corresponding Andreev boundary conditions are similar to that
in a spin-triplet superconductor - normal lead junction. We also study here a
quantum dot coupled to a normal lead and a Majorana Kramers pair and
investigate the effect of local repulsive interactions leading to an interplay
between Kondo and Majorana correlations. Using a combination of renormalization
group analysis and slave-boson mean-field theory, we show that the system flows
to a new fixed point which is controlled by the Majorana interaction rather
than the Kondo coupling. This Majorana fixed point is characterized by
correlations between the localized spin and the fermion parity of each spin
sector of the topological superconductor. We investigate the stability of the
Majorana phase with respect to Gaussian fluctuations.


title:
Stability and Occurrence Rate Constraints on the Planetary Sculpting
  Hypothesis for "Transitional" Disks

abstract:
  Transitional disks, protoplanetary disks with deep and wide central gaps, may
be the result of planetary sculpting. By comparing numerical planet-opening-gap
models with observed gaps, we find systems of 3-6 giant planets are needed in
order to open gaps with the observed depths and widths. We explore the
dynamical stability of such multi-planet systems using N-body simulations that
incorporate prescriptions for gas effects. We find they can be stable over a
typical disk lifetime, with the help of eccentricity damping from the residual
gap gas that facilitates planets locking into mean motion resonances. However,
in order to account for the occurrence rate of transitional disks, the planet
sculpting scenario demands gap-opening-friendly disk conditions, in particular,
a disk viscosity $\alpha\lesssim0.001$. In addition, the demography of giant
planets at $\sim 3-30$ AU separations, poorly constrained by current data, has
to largely follow occurrence rates extrapolated outward from radial velocity
surveys, not the lower occurrence rates extrapolated inward from direct imaging
surveys. Even with the most optimistic occurrence rates, transitional disks
cannot be a common phase that most gas disks experience at the end of their
life, as popularly assumed, simply because there are not enough planets to open
these gaps. Finally, as consequences of demanding almost all giant planets at
large separations participate in transitional disk sculpting, the majority of
such planets must form early and end up in a chain of mean motion resonances at
the end of disk lifetime.


title:
The connection between the host halo and the satellite galaxies of the
  Milky Way

abstract:
  Many properties of the Milky Way's dark matter halo, including its mass
assembly history, concentration, and subhalo population, remain poorly
constrained. We explore the connection between these properties of the Milky
Way and its satellite galaxy population, especially the implication of the
presence of the Magellanic Clouds for the properties of the Milky Way halo.
Using a suite of high-resolution $N$-body simulations of Milky Way-mass halos
with a fixed final Mvir ~ 10^{12.1}Msun, we find that the presence of
Magellanic Cloud-like satellites strongly correlates with the assembly history,
concentration, and subhalo population of the host halo, such that Milky
Way-mass systems with Magellanic Clouds have lower concentration, more rapid
recent accretion, and more massive subhalos than typical halos of the same
mass. Using a flexible semi-analytic galaxy formation model that is tuned to
reproduce the stellar mass function of the classical dwarf galaxies of the
Milky Way with Markov-Chain Monte-Carlo, we show that adopting host halos with
different mass-assembly histories and concentrations can lead to different
best-fit models for galaxy-formation physics, especially for the strength of
feedback. These biases arise because the presence of the Magellanic Clouds
boosts the overall population of high-mass subhalos, thus requiring a different
stellar-mass-to-halo-mass ratio to match the data. These biases also lead to
significant differences in the mass--metallicity relation, the kinematics of
low-mass satellites, the number counts of small satellites associated with the
Magellanic Clouds, and the stellar mass of Milky Way itself. Observations of
these galaxy properties can thus provide useful constraints on the properties
of the Milky Way halo.


title: The build-up of the red sequence in the Hercules cluster

abstract:
  We present the study of the colour-magnitude diagram of the cluster Abell
2151 (A2151), with a particular focus on the low-mass end. The deep
spectroscopy with AF2/WYFFOS@WHT and the caustic method enable us to obtain 360
members within 1.3 R_200 and absolute magnitude M_r < M*_r+6. This nearby
cluster shows a well defined red sequence up to M_r ~ - 18.5; at fainter
magnitudes only 36% of the galaxies lie on the extrapolation of the red
sequence. We compare the red sequences of A2151 and Abell 85, which is another
nearby cluster with similar spectroscopic data, but with different mass and
dynamical state. Both clusters show similar red sequences at the bright end
(M_r < -19.5), whereas large differences appear at the faint end. This result
suggests that the reddening of bright galaxies is independent of environment,
unlike the dwarf population (M_r > -18.0).


title: Function-Specific Mixing Times and Concentration Away from Equilibrium

abstract:
  Slow mixing is the central hurdle when working with Markov chains, especially
those used for Monte Carlo approximations (MCMC). In many applications, it is
only of interest to estimate the stationary expectations of a small set of
functions, and so the usual definition of mixing based on total variation
convergence may be too conservative. Accordingly, we introduce
function-specific analogs of mixing times and spectral gaps, and use them to
prove Hoeffding-like function-specific concentration inequalities. These
results show that it is possible for empirical expectations of functions to
concentrate long before the underlying chain has mixed in the classical sense,
and we show that the concentration rates we achieve are optimal up to
constants. We use our techniques to derive confidence intervals that are
sharper than those implied by both classical Markov chain Hoeffding bounds and
Berry-Esseen-corrected CLT bounds. For applications that require testing,
rather than point estimation, we show similar improvements over recent
sequential testing results for MCMC. We conclude by applying our framework to
real data examples of MCMC, providing evidence that our theory is both accurate
and relevant to practice.


title:
Non-Shannon inequalities in the entropy vector approach to causal
  structures

abstract:
  A causal structure is a relationship between observed variables that in
general restricts the possible correlations between them. This relationship can
be mediated by unobserved systems, modelled by random variables in the
classical case or joint quantum systems in the quantum case. One way to
differentiate between the correlations realisable by two different causal
structures is to use entropy vectors, i.e., vectors whose components correspond
to the entropies of each subset of the observed variables. To date, the
starting point for deriving entropic constraints within causal structures are
the so-called Shannon inequalities (positivity of entropy, conditional entropy
and conditional mutual information). In the present work we investigate what
happens when non-Shannon entropic inequalities are included as well. We show
that in general these lead to tighter outer approximations of the set of
realisable entropy vectors and hence enable a sharper distinction of different
causal structures. Since non-Shannon inequalities can only be applied amongst
classical variables, it might be expected that their use enables an entropic
distinction between classical and quantum causal structures. However, this
remains an open question. We also introduce techniques for deriving inner
approximations to the allowed sets of entropy vectors for a given causal
structure. These are useful for proving tightness of outer approximations or
for finding interesting regions of entropy space. We illustrate these
techniques in several scenarios, including the triangle causal structure.


title: Substructure within the SSA22 protocluster at $z\approx3.09$

abstract:
  We present the results of a densely sampled spectroscopic survey of the SSA22
protocluster at $z\approx 3.09$. Our sample with Keck/LRIS spectroscopy
includes 106 Ly$\alpha$ Emitters (LAEs) and 40 Lyman Break Galaxies (LBGs) at
$z=3.05-3.12$. These galaxies are contained within the $9'\times9'$ region in
which the protocluster was discovered, which also hosts the maximum galaxy
overdensity in the SSA22 region. The redshift histogram of our spectroscopic
sample reveals two distinct peaks, at $z=3.069$ (blue, 43 galaxies) and
$z=3.095$ (red, 103 galaxies). Furthermore, objects in the blue and red peaks
are segregated on the sky, with galaxies in the blue peak concentrating towards
the western half of the field. These results suggest that the blue and red
redshift peaks represent two distinct structures in physical space. Although
the double-peaked redshift histogram is traced in the same manner by LBGs and
LAEs, and brighter and fainter galaxies, we find that nine out of 10 X-ray AGNs
in SSA22, and all seven spectroscopically-confirmed giant Ly$\alpha$ "blobs,"
reside in the red peak. We combine our dataset with sparsely sampled
spectroscopy from the literature over a significantly wider area, finding
preliminary evidence that the double-peaked structure in redshift space extends
beyond the region of our dense spectroscopic sampling. In order to fully
characterize the three-dimensional structure, dynamics, and evolution of
large-scale structure in the SSA22 overdensity, we require the measurement of
large samples of LAE and LBG redshifts over a significantly wider area, as well
as detailed comparisons with cosmological simulations of massive cluster
formation.


title: Defocusing of Null Rays in Infinite Derivative Gravity

abstract:
  Einstein's General theory of relativity permits spacetime singularities,
where null geodesic congruences focus in the presence of matter, which
satisfies an appropriate energy condition. In this paper, we provide a minimal
defocusing condition for null congruences without assuming any Ansatz-dependent
background solution. The two important criteria are: (1) an additional scalar
degree of freedom, besides the massless graviton must be introduced into the
spacetime; and (2) an infinite derivative theory of gravity is required in
order to avoid tachyons or ghosts in the graviton propagator. In this regard,
our analysis strengthens earlier arguments for constructing non-singular
bouncing cosmologies within an infinite derivative theory of gravity, without
assuming any Ansatz to solve the full equations of motion.


title: Volumetric Survey Speed: A Figure of Merit for Transient Surveys

abstract:
  Time-domain surveys can exchange sky coverage for revisit frequency,
complicating the comparison of their relative capabilities. By using different
revisit intervals, a specific camera may execute surveys optimized for
discovery of different classes of transient objects. We propose a new figure of
merit, the instantaneous volumetric survey speed, for evaluating transient
surveys. This metric defines the trade between cadence interval and snapshot
survey volume and so provides a natural means of comparing survey capability.
The related metric of areal survey speed imposes a constraint on the range of
possible revisit times: we show that many modern time-domain surveys are
limited by the amount of fresh sky available each night. We introduce the
concept of "spectroscopic accessibility" and discuss its importance for
transient science goals requiring followup observing. We present an extension
of the control time algorithm for cases where multiple consecutive detections
are required. Finally, we explore how survey speed and choice of cadence
interval determine the detection rate of transients in the peak absolute
magnitude-decay timescale phase space.


title:
Improved detection of changes in species richness in high-diversity
  microbial communities

abstract:
  High throughput sequencing (HTS) continues to expand our understanding of
microbial communities, despite insufficient sequencing depths to detect all
rare taxa. These low abundance taxa are not accounted for in existing methods
for detecting changes in species richness. We address this with a new
hierarchical model that permits rigorous testing for both heterogeneity and
biodiversity changes, and simultaneously improves Type I & II error rates
compared to existing methods.


title: Power-law creep and residual stresses in a carbopol microgel

abstract:
  We report on the interplay between creep and residual stresses in a carbopol
microgel. When a constant shear stress $\sigma$ is applied below the yield
stress $\sigma_\text{y}$, the strain is shown to increase as a power law of
time, $\gamma(t)=\gamma_0 + (t/\tau)^\alpha$, with an exponent $\alpha=0.39\pm
0.04$ that is strongly reminiscent of Andrade creep in hard solids. For applied
shear stresses lower than some typical value $\sigma_\text{c}\simeq 0.2
\sigma_\text{y}$, the microgel experiences a more complex, anomalous creep
behaviour, characterized by an initial decrease of the strain, that we
attribute to the existence of residual stresses of the order of
$\sigma_\text{c}$ that persist after a rest time under a zero shear rate
following preshear. The influence of gel concentration on creep and residual
stresses are investigated as well as possible aging effects. We discuss our
results in light of previous works on colloidal glasses and other soft glassy
systems.


title:
The opportunity of the 2016 transit of Mercury for measuring the solar
  diameter and recommendations for the observation

abstract:
  The transit of Mercury occurred two times in this century: 2003, May 7 and
2006, November 8. In 2016 there is another opportunity to observe this
phenomenon and measure the solar diameter with the method of comparing the
ephemerides with the observations. This method has been presented by I. I.
Shapiro in 1980, the data of the observed transits (since 1631) have been
re-analyzed by Sveshnikov (2002) and an improvement on the observed data, to
avoid the confusion given by the black-drop effect, proposed by C. Sigismondi
and collaborators since 2005 exploits the measurement of the chord drawn by the
solar limb with the disk of the transiting planet and its extrapolation to zero
through the analytic chord fitting the observations before the black drop, in
the ingress/egress phases. A network of European observers (IOTA/ES) and
observatories (coronograph of Bialkow, PL 56 cm; IRSOL, Locarno CH - 45 cm
Gregorian telescope) is active for the 2016 transit. Recommendations to improve
the observation of the ingress/egress phases and examples of the data analysis
on the 1999 Mercury transit observed by TRACE are also done: the planet should
be centered in the field of view of the telescope to avoid optical distortions,
and the observations should be prolonged well after the black drop phase,
estimated in about 40 seconds and more after the internal contact t2 in the
ingress and before the internal contact t3 in egress.


title:
X-ray-induced photoemission yield for surface studies of solids beyond
  the photoelectron escape depth

abstract:
  X-ray-induced photoemission in materials research is commonly acknowledged as
a method with a probing depth limited by the escape depth of the
photoelectrons. This general statement should be complemented with exceptions
arising from the distribution of the X-ray wavefield in the material. Here we
show that the integral hard-X-ray-induced photoemission yield is modulated by
the Fresnel reflectivity of a multilayer structure with the signal originating
well below the photoelectron escape depth. A simple electric self-detection of
the integral photoemission yield and Fourier data analysis permit extraction of
thicknesses of individual layers. The approach does not require detection of
the reflected radiation and can be considered as a framework for non-invasive
evaluation of buried layers with hard X-rays under grazing incidence.


title:
Shape and Displacement Fluctuations in Soft Vesicles Filled by Active
  Particles

abstract:
  We investigate numerically the dynamics of shape and displacement
fluctuations of two-dimensional flexible vesicles filled with active particles.
At low concentration most of the active particles accumulate at the boundary of
the vesicle where positive particle number fluctuations are amplified by
trapping, leading to the formation of pinched spots of high density, curvature
and pressure. At high concentration the active particles cover the vesicle
boundary almost uniformly, resulting in fairly homogeneous pressure and
curvature, and nearly circular vesicle shape. The change between polarized and
spherical shapes is driven by the number of active particles. The
center-of-mass of the vesicle performs a persistent random walk with a long
time diffusivity that is strongly enhanced for elongated active particles due
to orientational correlations in their direction of propulsive motion.
  In our model shape-shifting induces directional sensing and the cell
spontaneously migrate along the polarization direction.


title: A Classification of Isomorphism-Invariant Random Digraphs

abstract:
  We classify isomorphism-invariant random digraphs according to where
randomness resides, namely, arcs, vertices, and vertices and arcs together
which in turn yield arc random digraphs (ARD), vertex random digraphs (VRD) and
vertex-arc random digraphs (VARD), respectively. This digraph classification
can be viewed as an extension of the classification of isomorphism-invariant
random graphs. We introduce randomness in the direction of the edges of a given
graph and obtain direction random digraphs (DRD) as well. We classify DRDs
according to which component is random in addition to the direction and study
the relations of DRDs with VARDs, VRDs and ARDs. We also consider random
nearest neighbor digraphs and determine their membership with respect to these
digraph families.


title: The Goodness of Simultaneous Fits in ISIS

abstract:
  In a previous work, we introduced a tool for analyzing multiple datasets
simultaneously, which has been implemented into ISIS. This tool was used to fit
many spectra of X-ray binaries. However, the large number of degrees of freedom
and individual datasets raise an issue about a good measure for a simultaneous
fit quality. We present three ways to check the goodness of these fits: we
investigate the goodness of each fit in all datasets, we define a combined
goodness exploiting the logical structure of a simultaneous fit, and we stack
the fit residuals of all datasets to detect weak features. These tools are
applied to all RXTE-spectra from GRO 1008-57, revealing calibration features
that are not detected significantly in any single spectrum. Stacking the
residuals from the best-fit model for the Vela X-1 and XTE J1859+083 data
evidences fluorescent emission lines that would have gone undetected otherwise.


title: Simultaneous fits in ISIS on the example of GRO J1008-57

abstract:
  Parallel computing and steadily increasing computation speed have led to a
new tool for analyzing multiple datasets and datatypes: fitting several
datasets simultaneously. With this technique, physically connected parameters
of individual data can be treated as a single parameter by implementing this
connection into the fit directly. We discuss the terminology, implementation,
and possible issues of simultaneous fits based on the X-ray data analysis tool
Interactive Spectral Interpretation System (ISIS). While all data modeling
tools in X-ray astronomy allow in principle fitting data from multiple data
sets individually, the syntax used in these tools is not often well suited for
this task. Applying simultaneous fits to the transient X-ray binary GRO
J1008-57, we find that the spectral shape is only dependent on X-ray flux. We
determine time independent parameters such as, e.g., the folding energy E_fold,
with unprecedented precision.


title: Exponential self-similar mixing by incompressible flows

abstract:
  We study the problem of the optimal mixing of a passive scalar under the
action of an incompressible flow in two space dimensions. The scalar solves the
continuity equation with a divergence-free velocity field, which satisfies a
bound in the Sobolev space $W^{s,p}$, where $s \geq 0$ and $1\leq p\leq
\infty$. The mixing properties are given in terms of a characteristic length
scale, called the mixing scale. We consider two notions of mixing scale, one
functional, expressed in terms of the homogeneous Sobolev norm $\dot H^{-1}$,
the other geometric, related to rearrangements of sets. We study rates of decay
in time of both scales under self-similar mixing. For the case $s=1$ and $1
\leq p \leq \infty$ (including the case of Lipschitz continuous velocities, and
the case of physical interest of enstrophy-constrained flows), we present
examples of velocity fields and initial configurations for the scalar that
saturate the exponential lower bound, established in previous works, on the
time decay of both scales. We also present several consequences for the
geometry of regular Lagrangian flows associated to Sobolev velocity fields.


title: All Known Hot RCB Stars Are Fading Fast Over the Last Century

abstract:
  The R Coronae Borealis (RCB) stars are cool supergiants that display
irregular and deep dips in their light curves, caused by dust formation. There
are four known hot RCB stars (DY Cen, MV Sgr, V348 Sgr, and HV 2671), with
surface temperatures of 15,000--25,000 K, and prior work has suggested that
three of these have secular fading in brightness. I have tested this result by
measuring century-long light curves in the Johnson B-band with modern
comparison star magnitudes, and I have extended this by measuring many
magnitudes over a wide time range as well as for the fourth hot RCB star. In
all four cases, the B-band magnitude of the maximum light is now fast fading.
The fading rates (in units of magnitudes per century) are 2.5 for DY Cen after
1960, 1.3 for MV Sgr, 1.3 for V348 Sgr, and 0.7 for HV 2671. This secular
fading is caused by the expected evolution of the star across the top of the HR
diagram at constant luminosity, as the temperature rises and the bolometric
correction changes. For DY Cen, the brightness at maximum light is rising from
1906 to 1932, and this is caused by the temperature increase from near 5,800 to
7,500 K. Before 1934 DY Cen had frequent dust dips, while after 1934 there are
zero dust dips, so there is some apparent connection between the rising
temperature and the formation of the dust. Thus, we have watched DY Cen evolve
from an ordinary RCB star up to a hot RCB star and now appearing as an extreme
helium star, all in under one century.


title:
Physical and chemical properties of Red MSX Sources in the southern sky:
  HII regions

abstract:
  We have studied the physical and chemical properties of 18 southern Red
Midcourse Space Experiment Sources (RMSs), using archival data taken from the
Atacama Pathfinder Experiment (APEX) Telescope Large Area Survey of the Galaxy,
the Australia Telescope Compact Array, and the Millimeter Astronomy Legacy Team
Survey at 90 GHz. Most of our sources have simple cometary/unresolved radio
emissions at 4.8 and/or 8.6GHz. The large number of Lyman continuum fluxes (NL)
indicates they are probably massive O- or early B-type star formation regions.
Archival IRAS infrared data are used to estimate the dust temperature, which is
about 30 K of our sources. Then, the H2 column densities and the
volume-averaged H2 number densities are estimated using the 0.87 mm dust
emissions. Large-scale infall and ionized accretions may be occurring in
G345.4881+00.3148. We also attempt to characterize the chemical properties of
these RMSs through molecular line (N2H+ (1-0) and HCO+ (1-0)) observations.
Most of the detected N2H+ and HCO+ emissions match well with the dust emission,
implying a close link to their chemical evolution in the RMSs. We found that
the abundance of N2H+ is one order of magnitude lower than that in other
surveys of infrared dark clouds, and a positive correlation between the
abundances of N2H+ and HCO+. The fractional abundance of N2H+ with respect to
H2 seems to decrease as a function of NL. These observed trends could be
interpreted as an indication of enhanced destruction of N2H+, either by CO or
through dissociative recombination with electrons produced by central UV
photons.


title: A Perspective Study on Content Management in E-Learning and M-Learning

abstract:
  This is the era of Information and Communication Technology (ICT). Nowadays,
there is no limit to learn, people can learn anywhere and anytime with the
enhancement of technology. Electronic Learning (E-learning) and Mobile Learning
(M-learning) are the two vital buzz terms in modern education particularly in
Education Enhanced Technology and Technologies Supported Learning. E-learning
is defined as the instructional content or learning experience delivered or
enabled by electronic technologies whereas, M-learning is defined simply as
learning via mobile devices such as cell phones, smart phones, palmtops, and
handheld computers. There are many similarities between the two technologies as
both are modern learning tools. Moreover, the latter is an extension and a
subset of the former. However, there are few limitations or differences still
exist in mobile learning tools, especially in the design, development and the
technology usability. In this paper we have mainly focused on how the digital
content is administrated (Content Management) in these two technologies.
Additionally, the content management in E and Mlearning are compared and their
similarities and differences are figured out.


title:
Signature of a polyamorphic transition in the THz spectrum of vitreous
  GeO2

abstract:
  The THz spectrum of density fluctuations, $S(Q, \omega)$, of vitreous GeO$_2$
at ambient temperature was measured by inelastic x-ray scattering from ambient
pressure up to pressures well beyond that of the known $\alpha$-quartz to
rutile polyamorphic (PA) transition. We observe significant differences in the
spectral shape measured below and above the PA transition, in particular, in
the 30-80 meV range. Guided by first-principle lattice dynamics calculations,
we interpret the changes in the phonon dispersion as the evolution from a
quartz-like to a rutile-like coordination. Notably, such a crossover is
accompanied by a cusp-like behavior in the pressure dependence of the elastic
response of the system. Overall, the presented results highlight the complex
fingerprint of PA phenomena on the high-frequency phonon dispersion.

categories: cond-mat.dis-nn cond-mat.mtrl-sci cond-mat.stat-mech physics.chem-ph


title:
Observations and analysis of a curved jet in the coma of comet
  67P/Churyumov-Gerasimenko

abstract:
  We analyze the physical properties and dynamical origin of a curved jet of
comet 67P/Churyumov-Gerasimenko that was observed repeatedly in several nucleus
rotations starting on May 30 and persisting until early August, 2015. We
simulated the motion of dust grains ejected from the nucleus surface under the
influence of the gravity and viscous drag effect of the expanding gas flow from
the rotating nucleus. The formation of the curved jet is a combination of the
size of the dust particles (~0.1-1 mm) and the location of the source region
near the nucleus equator. This enhances the spiral feature of the collimated
dust stream after the dust is accelerated to a terminal speed on the order of
m/s.


title: Fermi LAT Stacking Analysis of Swift Localized Gamma-ray Bursts

abstract:
  We perform a comprehensive stacking analysis of data collected by the Fermi
Large Area Telescope (LAT) of gamma-ray bursts (GRB) localized by the Swift
spacecraft, which were not detected by the LAT but which fell within the
instrument's field of view at the time of trigger. We examine a total of 79
GRBs by comparing the observed counts over a range of time intervals to that
expected from designated background orbits, as well as by using a joint
likelihood technique to model the expected distribution of stacked counts. We
find strong evidence for subthreshold emission at MeV to GeV energies using
both techniques. This observed excess is detected during intervals that include
and exceed the durations typically characterizing the prompt emission observed
at keV energies and lasts at least 2700 s after the co-aligned burst trigger.
By utilizing a novel cumulative likelihood analysis, we find that although a
burst's prompt gamma-ray and afterglow X-ray flux both correlate with the
strength of the subthreshold emission, the X-ray afterglow flux measured by
Swift's X-ray Telescope (XRT) at 11 hr post trigger correlates far more
significantly. Overall, the extended nature of the subthreshold emission and
its connection to the burst's afterglow brightness lend further support to the
external forward shock origin of the late-time emission detected by the LAT.
These results suggest that the extended high-energy emission observed by the
LAT may be a relatively common feature but remains undetected in a majority of
bursts owing to instrumental threshold effects.


title:
ViZDoom: A Doom-based AI Research Platform for Visual Reinforcement
  Learning

abstract:
  The recent advances in deep neural networks have led to effective
vision-based reinforcement learning methods that have been employed to obtain
human-level controllers in Atari 2600 games from pixel data. Atari 2600 games,
however, do not resemble real-world tasks since they involve non-realistic 2D
environments and the third-person perspective. Here, we propose a novel
test-bed platform for reinforcement learning research from raw visual
information which employs the first-person perspective in a semi-realistic 3D
world. The software, called ViZDoom, is based on the classical first-person
shooter video game, Doom. It allows developing bots that play the game using
the screen buffer. ViZDoom is lightweight, fast, and highly customizable via a
convenient mechanism of user scenarios. In the experimental part, we test the
environment by trying to learn bots for two scenarios: a basic move-and-shoot
task and a more complex maze-navigation problem. Using convolutional deep
neural networks with Q-learning and experience replay, for both scenarios, we
were able to train competent bots, which exhibit human-like behaviors. The
results confirm the utility of ViZDoom as an AI research platform and imply
that visual reinforcement learning in 3D realistic first-person perspective
environments is feasible.


title: Hausdorff dimension of limit sets

abstract:
  We exhibit a class of Schottky subgroups of $\mathbf{PU}(1,n)$ ($n \geq 2$)
which we call well-positioned and show that the Hausdorff dimension of the
limit set $\Lambda_\Gamma$ associated with such a subgroup $\Gamma$, with
respect to the spherical metric on the boundary of complex hyperbolic
$n$-space, is equal to the growth exponent $\delta_\Gamma$.
  For general $\Gamma$ we establish (under rather mild hypotheses) a lower
bound involving the dimension of the Patterson-Sullivan measure along
boundaries of complex geodesics.
  Our main tool is a version of the celebrated Ledrappier-Young theorem.


title:
Some Simulation Results for Emphatic Temporal-Difference Learning
  Algorithms

abstract:
  This is a companion note to our recent study of the weak convergence
properties of constrained emphatic temporal-difference learning (ETD)
algorithms from a theoretic perspective. It supplements the latter analysis
with simulation results and illustrates the behavior of some of the ETD
algorithms using three example problems.


title:
Projections of Patterson-Sullivan measures and the Mohammadi-Oh
  dichotomy

abstract:
  Let $\Gamma$ be some discrete subgroup of $\mathbf{SO}^o(n+1,\mathbf{R})$
with finite Bowen-Margulis-Sullivan measure. We study the dynamics of the
Bowen-Margulis-Sullivan measure with respect to closed connected subspaces of
the $N$ component in some Iwasawa decomposition
$\mathbf{SO}^o(n+1,\mathbf{R})=KAN$. We also study the dimension of projected
Patterson-Sullivan measures along some fixed small circle.


title: Quasiparticle anisotropic hydrodynamics for central collisions

abstract:
  We use quasiparticle anisotropic hydrodynamics to study an
azimuthally-symmetric boost-invariant quark-gluon plasma including the effects
of both shear and bulk viscosities. In quasiparticle anisotropic hydrodynamics,
a single finite-temperature quasiparticle mass is introduced and fit to the
lattice data in order to implement a realistic equation of state. We compare
results obtained using the quasiparticle method with the standard method of
imposing the equation of state in anisotropic hydrodynamics and viscous
hydrodynamics. Using these three methods, we extract the primordial particle
spectra, total number of charged particles, and average transverse momentum for
various values of the shear viscosity to entropy density ratio eta/s. We find
that the three methods agree well for small shear viscosity to entropy density
ratio, eta/s, but differ at large eta/s. We find, in particular, that when
using standard viscous hydrodynamics, the bulk-viscous correction can drive the
primordial particle spectra negative at large p_T which is clearly unphysical.
Such a behavior is not seen in either anisotropic hydrodynamics approach,
irrespective of the value of eta/s.


title: Triple planes with p_g=q=0

abstract:
  We show that general triple planes with p_g=q=0 belong to at most 12
families, that we call surfaces of type I,..., XII, and we prove that the
corresponding Tschirnhausen bundle is direct sum of two line bundles in cases
I, II, III, whereas is a rank 2 Steiner bundle in the remaining cases.
  We also provide existence results and explicit constructions for surfaces of
type I,..., VII, recovering all classical examples and discovering several new
ones. In particular, triple planes of type VII provide counterexamples to a
wrong claim made in 1942 by Bronowski.


title: Counting loxodromics for hyperbolic actions

abstract:
  Let $G \curvearrowright X$ be a nonelementary action by isometries of a
hyperbolic group $G$ on a hyperbolic metric space $X$. We show that the set of
elements of $G$ which act as loxodromic isometries of $X$ is generic. That is,
for any finite generating set of $G$, the proportion of $X$--loxodromics in the
ball of radius $n$ about the identity in $G$ approaches $1$ as $n \to \infty$.
We also establish several results about the behavior in $X$ of the images of
typical geodesic rays in $G$; for example, we prove that they make linear
progress in $X$ and converge to the Gromov boundary $\partial X$. Our
techniques make use of the automatic structure of $G$, Patterson--Sullivan
measure on $\partial G$, and the ergodic theory of random walks for groups
acting on hyperbolic spaces. We discuss various applications, in particular to
Mod(S), Out($F_N$), and right--angled Artin groups.


title:
Nanosecond-timescale low error switching of in-plane magnetic tunnel
  junctions through dynamic Oersted-field assisted spin-Hall effect

abstract:
  We investigate fast-pulse switching of in-plane-magnetized magnetic tunnel
junctions (MTJs) within 3-terminal devices in which spin-transfer torque is
applied to the MTJ by the giant spin Hall effect. We measure reliable
switching, with write error rates down to $10^{-5}$, using current pulses as
short as just 2 ns in duration. This represents the fastest reliable switching
reported to date for any spin-torque-driven magnetic memory geometry, and
corresponds to a characteristic time scale that is significantly shorter than
predicted possible within a macrospin model for in-plane MTJs subject to
thermal fluctuations at room temperature. Using micromagnetic simulations, we
show that in the 3-terminal spin-Hall devices the Oersted magnetic field
generated by the pulse current strongly modifies the magnetic dynamics excited
by the spin-Hall torque, enabling this unanticipated performance improvement.
Our results suggest that in-plane MTJs controlled by Oersted-field-assisted
spin-Hall torque are a promising candidate for both cache memory applications
requiring high speed and for cryogenic memories requiring low write energies.


title: Distributed Learning with Infinitely Many Hypotheses

abstract:
  We consider a distributed learning setup where a network of agents
sequentially access realizations of a set of random variables with unknown
distributions. The network objective is to find a parametrized distribution
that best describes their joint observations in the sense of the
Kullback-Leibler divergence. Apart from recent efforts in the literature, we
analyze the case of countably many hypotheses and the case of a continuum of
hypotheses. We provide non-asymptotic bounds for the concentration rate of the
agents' beliefs around the correct hypothesis in terms of the number of agents,
the network parameters, and the learning abilities of the agents. Additionally,
we provide a novel motivation for a general set of distributed Non-Bayesian
update rules as instances of the distributed stochastic mirror descent
algorithm.


title: Primordial features and Planck polarization

abstract:
  With the Planck 2015 Cosmic Microwave Background (CMB) temperature and
polarization data, we search for possible features in the primordial power
spectrum (PPS). We revisit the Wiggly Whipped Inflation (WWI) framework and
demonstrate how generation of some particular primordial features can improve
the fit to Planck data. WWI potential allows the scalar field to transit from a
steeper potential to a nearly flat potential through a discontinuity either in
potential or in its derivatives. WWI offers the inflaton potential
parametrizations that generate a wide variety of features in the primordial
power spectra incorporating most of the localized and non-local inflationary
features that are obtained upon reconstruction from temperature and
polarization angular power spectrum. At the same time, in a single framework it
allows us to have a background parameter estimation with a nearly free-form
primordial spectrum. Using Planck 2015 data, we constrain the primordial
features in the context of Wiggly Whipped Inflation and present the features
that are supported both by temperature and polarization. WWI model provides
more than $13$ improvement in $\chi^2$ fit to the data with respect to the best
fit power law model considering combined temperature and polarization data from
Planck and B-mode polarization data from BICEP and Planck dust map. We use 2-4
extra parameters in the WWI model compared to the featureless strict slow roll
inflaton potential. We find that the differences between the temperature and
polarization data in constraining background cosmological parameters such as
baryon density, cold dark matter density are reduced to a good extent if we use
primordial power spectra from WWI. We also discuss the extent of bispectra
obtained from the best potentials in arbitrary triangular configurations using
the BI-spectra and Non-Gaussianity Operator (BINGO).


title: Linearization of the Relativistic Oscillator Hierarchy

abstract:
  This paper is based on MacColl's [1] solution of the equation of motion for a
linear (harmonic) oscillator subject to the laws of special relativity in the
rest frame of the center of attraction. MacColl's result can be extended to the
quartic oscillator in this frame with one extremely simple adjustment of the
linearization map given in Anderson [2]. In fact, it can be extended to all the
attractive oscillators in this frame.


title:
Optical-lattice-assisted magnetic phase transition in a
  spin-orbit-coupled Bose-Einstein condensate

abstract:
  We investigate the effect of a periodic potential generated by a
one-dimensional optical lattice on the magnetic properties of an $S=1/2$
spin-orbit-coupled Bose gas. By increasing the lattice strength one can achieve
a magnetic phase transition between a polarized and an unpolarized Bloch wave
phase, characterized by a significant enhancement of the contrast of the
density fringes. If the wave vector of the periodic potential is chosen close
to the roton momentum, the transition could take place at very small lattice
intensities, revealing the strong enhancement of the response of the system to
a weak density perturbation. By solving the Gross-Pitaevskii equation in the
presence of a three-dimensional trapping potential, we shed light on the
possibility of observing the magnetic phase transition in currently available
experimental conditions.


title: Strictly-complete measurements for bounded-rank quantum-state tomography

abstract:
  We consider the problem of quantum-state tomography under the assumption that
the state is pure, and more generally that its rank is bounded by a given value
$r$. In this scenario two notions of informationally complete measurements
emerge: rank-$r$ complete measurements and rank-$r$ strictly-complete
measurements. Whereas in the first notion, a rank-$r$ state is uniquely
identified from within the set of rank-$r$ states, in the second notion the
same state is uniquely identified from within the set of all physical states,
of any rank. We argue, therefore, that strictly-complete measurements are
compatible with convex optimization, and we prove that they allow robust
quantum state estimation in the presence of experimental noise. We also show
that rank-$r$ strictly-complete measurements are as efficient as rank-$r$
complete measurements. We construct examples of strictly-complete measurements
and give a complete description of their structure in the context of matrix
completion. Moreover, we numerically show that a few random bases form such
measurements. We demonstrate the efficiency-robustness property for different
strictly-complete measurements with numerical experiments. We thus conclude
that only strictly-complete measurements are useful for practical tomography.


title: Unitary model for atomic ionization by intense XUV laser pulses

abstract:
  A unitary model describing the electronic transitions in an atom subject to a
strong high frequency laser pulse is proposed. The model fully accounts for the
initial state coupling with the continuum spectrum. Continuum-continuum as well
as discrete-discrete transitions are neglected. The model leads to a single
integro-differential equation for the initial state amplitude. Exact numerical
and approximate closed semi-analytical solutions of this equation are obtained.
A comparison of present results with full time dependent Schr\"odinger equation
solution for Hydrogen atoms subject to a laser pulse is presented. The initial
state time dependent population is rather well described by the model and two
approximate solutions. The electron energy spectrum is also well reproduced by
the model and by a new improved Weiskopf-Wigner related approximation.


title:
Kinetic Sunyaev Zeldovich effect in an anisotropic CMB model: measuring
  low multipoles of the CMB at higher redshifts using intensity and
  polarization spectral distortions

abstract:
  We present a novel mathematical formalism that allows to easily compute the
expected kinetic Sunyaev Zeldovich (kSZ) signal in intensity and polarization
due to an anisotropic primordial Cosmic Microwave Background (CMB). We derive
the expected intensity and polarization distortions in the direction of
non-moving galaxy clusters and then we generalize our calculations for non-zero
peculiar velocity. We show that, in the direction of moving clusters, low CMB
multipoles impose intensity and polarization spectral distortions with
different frequency dependences. The polarization signal primarily probes the
quadrupole moment of the CMB, with a significant contribution from the
primordial dipole and octupole moments. For a typical cluster velocity of 1000
km/s, corrections to the quadrupole-induced polarization of a non-moving
cluster are of the order of 2-10% between 200-600 GHz, and depend on cluster's
position on the sky, velocity magnitude and direction of motion. We also find
that the angular dependence of the signal varies with frequency of observation.
The distinct frequency and angular dependences of the polarization induced by
the primordial dipole and octupole can be exploited to measure them despite
other physical effects and foregrounds. Contrary to polarization, intensity
distortions are affected by all the CMB multipoles, so they cannot be readily
used to probe the low multipoles at higher redshifts. However, correlations
between intensity and polarization signals, can be used to enhance the signal
to noise ratio for the measurements of the primordial dipole, quadrupole and
octupole. The more general calculation of the aberration kernel presented in
this work has applications reaching beyond the SZ cluster science addressed
here. For example, it can be exploited to the deboost/deaberrate CMB multipoles
as observed in our local frame.


title:
Attribute And-Or Grammar for Joint Parsing of Human Attributes, Part and
  Pose

abstract:
  This paper presents an attribute and-or grammar (A-AOG) model for jointly
inferring human body pose and human attributes in a parse graph with attributes
augmented to nodes in the hierarchical representation. In contrast to other
popular methods in the current literature that train separate classifiers for
poses and individual attributes, our method explicitly represents the
decomposition and articulation of body parts, and account for the correlations
between poses and attributes. The A-AOG model is an amalgamation of three
traditional grammar formulations: (i) Phrase structure grammar representing the
hierarchical decomposition of the human body from whole to parts; (ii)
Dependency grammar modeling the geometric articulation by a kinematic graph of
the body pose; and (iii) Attribute grammar accounting for the compatibility
relations between different parts in the hierarchy so that their appearances
follow a consistent style. The parse graph outputs human detection, pose
estimation, and attribute prediction simultaneously, which are intuitive and
interpretable. We conduct experiments on two tasks on two datasets, and
experimental results demonstrate the advantage of joint modeling in comparison
with computing poses and attributes independently. Furthermore, our model
obtains better performance over existing methods for both pose estimation and
attribute prediction tasks.


title: Likelihood Inflating Sampling Algorithm

abstract:
  Markov Chain Monte Carlo (MCMC) sampling from a posterior distribution
corresponding to a massive data set can be computationally prohibitive since
producing one sample requires a number of operations that is linear in the data
size. In this paper, we introduce a new communication-free parallel method, the
Likelihood Inflating Sampling Algorithm (LISA), that significantly reduces
computational costs by randomly splitting the dataset into smaller subsets and
running MCMC methods independently in parallel on each subset using different
processors. Each processor will be used to run an MCMC chain that samples
sub-posterior distributions which are defined using an "inflated" likelihood
function. We develop a strategy for combining the draws from different
sub-posteriors to study the full posterior of the Bayesian Additive Regression
Trees (BART) model. The performance of the method is tested using both
simulated and real data.


title: The semilinear heat equation on sparse random graphs

abstract:
  Using the theory of $L^p$-graphons (Borgs et al, 2014), we derive and
rigorously justify the continuum limit for systems of differential equations on
sparse random graphs. Specifically, we show that the solutions of the initial
value problems for the discrete models can be approximated by those of an
appropriate nonlocal diffusion equation. Our results apply to a range of
spatially extended dynamical models of different physical, biological, social,
and economic networks. Importantly, our assumptions cover network topologies
featured in many important real-world networks. In particular, we derive the
continuum limit for coupled dynamical systems on power law graphs. The latter
is the main motivation for this work.


title: Don't Walk, Skip! Online Learning of Multi-scale Network Embeddings

abstract:
  We present Walklets, a novel approach for learning multiscale representations
of vertices in a network. In contrast to previous works, these representations
explicitly encode multiscale vertex relationships in a way that is analytically
derivable.
  Walklets generates these multiscale relationships by subsampling short random
walks on the vertices of a graph. By `skipping' over steps in each random walk,
our method generates a corpus of vertex pairs which are reachable via paths of
a fixed length. This corpus can then be used to learn a series of latent
representations, each of which captures successively higher order relationships
from the adjacency matrix.
  We demonstrate the efficacy of Walklets's latent representations on several
multi-label network classification tasks for social networks such as
BlogCatalog, DBLP, Flickr, and YouTube. Our results show that Walklets
outperforms new methods based on neural matrix factorization. Specifically, we
outperform DeepWalk by up to 10% and LINE by 58% Micro-F1 on challenging
multi-label classification tasks. Finally, Walklets is an online algorithm, and
can easily scale to graphs with millions of vertices and edges.


title: Single-Interface Casimir Torque

abstract:
  It is shown that the quantum fluctuations of the electromagnetic field
generally induce a torque at the interface of an anisotropic material with
another anisotropic or isotropic material. It is proven that this torque
depends on an interface zero-point energy determined by the dispersion of the
interface (localized and extended) modes. Our theory demonstrates that the
single-interface torque is essential to understand the Casimir physics of
material systems with anisotropic elements and determines the equilibrium
positions of the system.


title: Evolutes of plane curves and null curves in Minkowski $3$-space

abstract:
  We use the isotropic projection of Laguerre geometry in order to establish a
correspondence between plane curves and null curves in the Minkowski $3$-space.
We describe the geometry of null curves (Cartan frame, pseudo-arc parameter,
pseudo-torsion, pairs of associated curves) in terms of the curvature of the
corresponding plane curves. This leads to an alternative description of all
plane curves which are Laguerre congruent to a given one.


title: Percolation of optical excitation mediated by near-field interactions

abstract:
  Optical excitation transfer in nanostructured matter has been intensively
studied in various material systems for versatile applications. Herein, we
discuss the percolation of optical excitations in randomly organized
nanostructures caused by optical near-field interactions governed by Yukawa
potential in a two-dimensional stochastic model. The model results demonstrate
the appearance of two phases of percolation of optical excitation as a function
of the localization degree of near-field interaction. Moreover, it indicates
sublinear scaling with percolation distance when the light localization is
strong. The results provide fundamental insights into optical excitation
transfer and will facilitate the design and analysis of nanoscale
signal-transfer characteristics.


title: Single-shot 3D motion picture camera with a dense point cloud

abstract:
  We introduce a method and a 3D-camera for single-shot 3D shape measurement,
with unprecedented features: The 3D-camera does not rely on pattern
codification and acquires object surfaces at the theoretical limit of the
information efficiency: Up to 30% of the available camera pixels display
independent (not interpolated) 3D points. The 3D-camera is based on
triangulation with two properly positioned cameras and a projected multi-line
pattern, in combination with algorithms that solve the ambiguity problem. The
projected static line pattern enables 3D-acquisition of fast processes and the
take of 3D-motion-pictures. The depth resolution is at its physical limit,
defined by electronic noise and speckle noise. The requisite low cost
technology is simple.


title: Optical nano artifact metrics using silicon random nanostructures

abstract:
  Nano artifact metrics exploit unique physical attributes of nanostructured
matter for authentication and clone resistance, which is vitally important in
the age of Internet-of-Things where securing identities is critical. However,
high-cost and huge experimental apparatuses, such as scanning electron
microscopy, have been required in the former studies. Herein, we demonstrate an
optical approach to characterise the nanoscale-precision signatures of silicon
random structures towards realising low-cost and high-value information
security technology. Unique and versatile silicon nanostructures are generated
via resist collapse phenomena, which contains dimensions that are well below
the diffraction limit of light. We exploit the nanoscale precision ability of
confocal laser microscopy in the height dimension, and our experimental results
demonstrate that the vertical precision of measurement is essential in
satisfying the performances required for artifact metrics. Furthermore, by
using state-of-the-art nanostructuring technology, we experimentally fabricate
clones from the genuine devices. We demonstrate that the statistical properties
of the genuine and clone devices are successfully exploited, showing that the
liveness-detection-type approach, which is widely deployed in biometrics, is
valid in artificially-constructed solid-state nanostructures. These findings
pave the way for reasonable and yet sufficiently secure novel principles for
information security based on silicon random nanostructures and optical
technologies.


title:
Convergence Rate for a Radau hp Collocation Method Applied to
  Constrained Optimal Control

abstract:
  For unconstrained control problems, a local convergence rate is established
for an $hp$-method based on collocation at the Radau quadrature points in each
mesh interval of the discretization. If the continuous problem has a
sufficiently smooth solution and the Hamiltonian satisfies a strong convexity
condition, then the discrete problem possesses a local minimizer in a
neighborhood of the continuous solution, and as either the number of
collocation points or the number of mesh intervals increase, the discrete
solution convergences to the continuous solution in the sup-norm. The
convergence is exponentially fast with respect to the degree of the polynomials
on each mesh interval, while the error is bounded by a polynomial in the mesh
spacing. An advantage of the $hp$-scheme over global polynomials is that there
is a convergence guarantee when the mesh is sufficiently small, while the
convergence result for global polynomials requires that a norm of the
linearized dynamics is sufficiently small. Numerical examples explore the
convergence theory.


title:
Perturbatively deformed defects in P\"oschl-Teller-driven scenarios for
  quantum mechanics

abstract:
  P\"oschl-Teller-driven solutions for quantum mechanical fluctuations are
triggered off by single scalar field theories obtained through a systematic
perturbative procedure for generating deformed defects. The analytical
properties concerning the quantum fluctuations in one-dimension, zero-mode
states, first- and second- excited states, and energy density profiles are all
obtained from deformed topological and non-topological structures supported by
real scalar fields. Results are firstly derived from an integrated $\lambda
\phi^4$ theory, with corresponding generalizations applied to starting $\lambda
\chi^4$ and {\em sine}-Gordon theories. By focusing our calculations on
structures supported by the $\lambda\phi^4$ theory, the outcome of our study
suggests an exact quantitative correspondence to P\"oschl-Teller-driven
systems. Embedded into the perturbative quantum mechanics framework, such a
correspondence turns into a helpful tool for computing excited states and
continuous mode solutions, as well as their associated energy spectrum, for
quantum fluctuations of perturbatively deformed structures. Perturbative
deformations create distinct physical scenarios in the context of exactly
solvable quantum systems and may also work as an analytical support for
describing novel braneworld universes embedded into a $5$-dimensional gravity
bulks.


title: Average Size of a Suffix Tree for Markov Sources

abstract:
  We study a suffix tree built from a sequence generated by a Markovian source.
Such sources are more realistic probabilistic models for text generation, data
compression, molecular applications, and so forth. We prove that the average
size of such a suffix tree is asymptotically equivalent to the average size of
a trie built over $n$ independent sequences from the same Markovian source.
This equivalence is only known for memoryless sources. We then derive a formula
for the size of a trie under Markovian model to complete the analysis for
suffix trees. We accomplish our goal by applying some novel techniques of
analytic combinatorics on words also known as analytic pattern matching.


title: Bounds on the connected forcing number of a graph

abstract:
  In this paper, we study (zero) forcing sets which induce connected subgraphs
of a graph. The minimum cardinality of such a set is called the connected
forcing number of the graph. We provide sharp upper and lower bounds on the
connected forcing number in terms of the minimum degree, maximum degree, girth,
and order of the graph.


title: Free Hilbert Transforms

abstract:
  We study analogues of classical Hilbert transforms as fourier multipliers on
free groups. We prove their complete boundedness on non commutative $L^p$
spaces associated with the free group von Neumann algebras for all
$1<p<\infty$. This implies that the decomposition of the free group $\F_\infty$
into reduced words starting with distinct free generators is completely
unconditional in $L^p$. We study the case of Voiculescu's amalgamated free
products of von Neumann algebras as well. As by-products, we obtain a positive
answer to a compactness-problem posed by Ozawa, a length independent estimate
for Junge-Parcet-Xu's free Rosenthal inequality, a Littlewood-Paley-Stein type
inequality for geodesic paths of free groups, and a length reduction formula
for $L^p$-norms of free group von Neumann algebras.


title: Deep space experiment to measure $G$

abstract:
  Responding to calls from the National Science Foundation (NSF) for new
proposals to measure the gravitational constant $G$, we offer an interesting
experiment in deep space employing the classic gravity train mechanism. Our
setup requires three bodies: a larger layered solid sphere with a cylindrical
hole through its center, a much smaller retroreflector which will undergo
harmonic motion within the hole and a host spacecraft with laser ranging
capabilities to measure round trip light-times to the retroreflector but
ultimately separated a significant distance away from the sphere-retroreflector
apparatus. Measurements of the period of oscillation of the retroreflector in
terms of host spacecraft clock time using existing technology could give
determinations of $G$ nearly three orders of magnitude more accurate than
current measurements here on Earth. However, significant engineering advances
in the release mechanism of the apparatus from the host spacecraft will likely
be necessary. Issues with regard to the stability of the system are briefly
addressed.


title: Prime Factorization Using Magnonic Holographic Device

abstract:
  Determining the prime factors of a given number N is a problem, which
requires super-polynomial time for conventional digital computers. A
polynomial-time algorithm was invented by P. Shor for quantum computers.
However, the realization of quantum computers is associated with significant
technological challenges in achieving and preserving quantum entanglement.
Prime factorization can be also solved by using classical wave interference
without quantum entanglement. In this work, we present experimental data
showing prime factorization by utilizing spin wave interference. The prime
factorization includes three major steps. First, general type computer
calculates the sequence of numbers mkmod(N), where N is the number to be
factorized, m is a randomly chosen positive integer, and k=0,1,2,3,4,5,6 .. .
Next, the period of calculated sequence r is determined by exploiting spin wave
interference. Finally, the general type computer finds the primes based on the
obtained r. The experiment on the period finding was accomplished on the
6-terminal Y3Fe2(FeO4)3 device. We chose number 15 for a test and found its
primes in a sequence of measurements. The obtained data demonstrate an example
of solving a prime factorization problem using classical wave interference. We
discuss the physical and technological limitations of this approach, which
define the maximum size of N and the computational speed. Though this classical
approach cannot compete with the quantum algorithm in efficiency, magnonic
holographic devices can be potentially utilized as complementary logic units
aimed to speed up prime factorization with classical computers.


title: Note on asymptotically conical expanding Ricci solitons

abstract:
  We show that at the level of formal expansions, any compact Riemannian
manifold is the sphere at infinity of an asymptotically conical gradient
expanding Ricci soliton.


title:
Adobe-MIT submission to the DSTC 4 Spoken Language Understanding pilot
  task

abstract:
  The Dialog State Tracking Challenge 4 (DSTC 4) proposes several pilot tasks.
In this paper, we focus on the spoken language understanding pilot task, which
consists of tagging a given utterance with speech acts and semantic slots. We
compare different classifiers: the best system obtains 0.52 and 0.67 F1-scores
on the test set for speech act recognition for the tourist and the guide
respectively, and 0.52 F1-score for semantic tagging for both the guide and the
tourist.


title: Robust Dialog State Tracking for Large Ontologies

abstract:
  The Dialog State Tracking Challenge 4 (DSTC 4) differentiates itself from the
previous three editions as follows: the number of slot-value pairs present in
the ontology is much larger, no spoken language understanding output is given,
and utterances are labeled at the subdialog level. This paper describes a novel
dialog state tracking method designed to work robustly under these conditions,
using elaborate string matching, coreference resolution tailored for dialogs
and a few other improvements. The method can correctly identify many values
that are not explicitly present in the utterance. On the final evaluation, our
method came in first among 7 competing teams and 24 entries. The F1-score
achieved by our method was 9 and 7 percentage points higher than that of the
runner-up for the utterance-level evaluation and for the subdialog-level
evaluation, respectively.


title: Partial Covering Arrays: Algorithms and Asymptotics

abstract:
  A covering array $\mathsf{CA}(N;t,k,v)$ is an $N\times k$ array with entries
in $\{1, 2, \ldots , v\}$, for which every $N\times t$ subarray contains each
$t$-tuple of $\{1, 2, \ldots , v\}^t$ among its rows. Covering arrays find
application in interaction testing, including software and hardware testing,
advanced materials development, and biological systems. A central question is
to determine or bound $\mathsf{CAN}(t,k,v)$, the minimum number $N$ of rows of
a $\mathsf{CA}(N;t,k,v)$. The well known bound
$\mathsf{CAN}(t,k,v)=O((t-1)v^t\log k)$ is not too far from being
asymptotically optimal. Sensible relaxations of the covering requirement arise
when (1) the set $\{1, 2, \ldots , v\}^t$ need only be contained among the rows
of at least $(1-\epsilon)\binom{k}{t}$ of the $N\times t$ subarrays and (2) the
rows of every $N\times t$ subarray need only contain a (large) subset of $\{1,
2, \ldots , v\}^t$. In this paper, using probabilistic methods, significant
improvements on the covering array upper bound are established for both
relaxations, and for the conjunction of the two. In each case, a randomized
algorithm constructs such arrays in expected polynomial time.


title: End-to-end evaluation of research organizations

abstract:
  End-to-end research evaluation needs to separate out the bibliometric part of
the chain from the econometric part. We first introduce the role of
size-dependent and size-independent indicators in the bibliometric part of the
evaluation chain. We show that performance can then be evaluated at various
levels, namely a zeroth-order, a first-order or even a second-order. To
complete the evaluation chain, we take up the econometric part where efficiency
of the research production process is represented in terms of output and
outcome productivities. Both size-dependent and size-independent terms play a
crucial role to combine quantity and quality (impact) in a meaningful way.
Output or outcome at the bibliometric level can be measured using zeroth, first
or second-order composite indicators, and the productivity terms follow
accordingly using the input to output or outcome factors.


title:
Weak coupling of pseudoacoustic phonons and magnon dynamics in
  incommensurate spin ladder compound Sr14Cu24O41

abstract:
  Intriguing lattice dynamics has been predicted for aperiodic crystals that
contain incommensurate substructures. Here we report inelastic neutron
scattering measurements of phonon and magnon dispersions in Sr14Cu24O41, which
contains incommensurate one-dimensional (1D) chain and two-dimensional (2D)
ladder substructures. Two distinct pseudoacoustic phonon modes, corresponding
to the sliding motion of one sublattice against the other, are observed for
atomic motions polarized along the incommensurate axis. In the long wavelength
limit, it is found that the sliding mode shows a remarkably small energy gap of
1.7-1.9 meV, indicating very weak interactions between the two incommensurate
sublattices. The measurements also reveal a gapped and steep linear magnon
dispersion of the ladder sublattice. The high group velocity of this magnon
branch and weak coupling with acoustic and pseudoacoustic phonons can explain
the large magnon thermal conductivity in Sr14Cu24O41 crystals. In addition, the
magnon specific heat is determined from the measured total specific heat and
phonon density of states, and exhibits a Schottky anomaly due to gapped magnon
modes of the spin chains. These findings offer new insights into the phonon and
magnon dynamics and thermal transport properties of incommensurate magnetic
crystals that contain low-dimensional substructures.


title: Neural Recovery Machine for Chinese Dropped Pronoun

abstract:
  Dropped pronouns (DPs) are ubiquitous in pro-drop languages like Chinese,
Japanese etc. Previous work mainly focused on painstakingly exploring the
empirical features for DPs recovery. In this paper, we propose a neural
recovery machine (NRM) to model and recover DPs in Chinese, so that to avoid
the non-trivial feature engineering process. The experimental results show that
the proposed NRM significantly outperforms the state-of-the-art approaches on
both two heterogeneous datasets. Further experiment results of Chinese zero
pronoun (ZP) resolution show that the performance of ZP resolution can also be
improved by recovering the ZPs to DPs.


title: A remark about supramenability and the Macaev norm

abstract:
  We show that a finitely generated group G which satisfies a certain condition
with respect to the Macaev norm is supramenable. The condition is equivalent to
the existence of quasicentral approximate unit with respect to the Macaev norm
relative to the left regular representation of the group and has been studied
by the author in connection with perturbation questions for Hilbert space
operators. The condition can be also viewed as an analogue with respect to the
Macaev norm of Yamasaki parabolicity. We also show that existence of
quasicentral approximate units relative to the Macaev norm for n-tuples of
operators is not preserved when taking tensor products.


title: Superfluid Density of a Spin-orbit Coupled Bose Gas

abstract:
  We discuss the superfluid properties of a Bose-Einstein condensed gas with
spin-orbit coupling, recently realized in experiments. We find a finite normal
fluid density $\rho_n$ at zero temperature which turns out to be a function of
the Raman coupling. In particular, the entire fluid becomes normal at the
transition point from the zero momentum to the plane wave phase, even though
the condensate fraction remains finite. We emphasize the crucial role played by
the gapped branch of the elementary excitations and discuss its contributions
to various sum rules. Finally, we prove that an independent definition of
superfluid density $\rho_s$, using the phase twist method, satisfies the
equality $\rho_n+\rho_s=\rho$, the total density, despite the breaking of
Galilean invariance.


title:
A NuSTAR observation of the reflection spectrum of the low mass X-ray
  binary 4U 1728-34

abstract:
  We report on a simultaneous NuSTAR and Swift observation of the neutron star
low-mass X-ray binary 4U 1728-34. We identified and removed four Type I X-ray
bursts during the observation in order to study the persistent emission. The
continuum spectrum is hard and well described by a black body with $kT=$ 1.5
keV and a cutoff power law with $\Gamma=$ 1.5 and a cutoff temperature of 25
keV. Residuals between 6 and 8 keV provide strong evidence of a broad Fe
K$\alpha$ line. By modeling the spectrum with a relativistically blurred
reflection model, we find an upper limit for the inner disk radius of $R_{\rm
in}\leq2 R_{\rm ISCO}$. Consequently we find that $R_{\rm NS}\leq23$ km,
assuming $M=1.4{\mbox{$\rm\,M_{\mathord\odot}$}}$ and $a=0.15$. We also find an
upper limit on the magnetic field of $B\leq2\times10^8$ G.


title:
Intelligent Initialization and Adaptive Thresholding for Iterative
  Matrix Completion; Some Statistical and Algorithmic Theory for
  Adaptive-Impute

abstract:
  Over the past decade, various matrix completion algorithms have been
developed. Thresholded singular value decomposition (SVD) is a popular
technique in implementing many of them. A sizable number of studies have shown
its theoretical and empirical excellence, but choosing the right threshold
level still remains as a key empirical difficulty. This paper proposes a novel
matrix completion algorithm which iterates thresholded SVD with
theoretically-justified and data-dependent values of thresholding parameters.
The estimate of the proposed algorithm enjoys the minimax error rate and shows
outstanding empirical performances. The thresholding scheme that we use can be
viewed as a solution to a non-convex optimization problem, understanding of
whose theoretical convergence guarantee is known to be limited. We investigate
this problem by introducing a simpler algorithm, generalized-\SI, analyzing its
convergence behavior, and connecting it to the proposed algorithm.


title: Micropolarity Ramification of Asymmetric Merging Flow

abstract:
  The steady, asymmetric and two-dimensional flow of viscous, incompressible
micropolar fluid through a rectangular channel with a splitter (parallel to
walls) was formulated and simulated numerically. The plane Poiseuille flow was
considered far from upstream and downstream of the splitter. The geometric
parameter that controls the position of splitter was defined as splitter
position parameter. A numerical scheme that comprises a fourth order method
followed by special finite-difference method was used to solve the boundary
value problem. This numerical scheme transforms the governing equations to
system of finite difference equations which we have solved by SOR iterative
method. Moreover, the results obtained were further refined and upgraded by the
Richardson extrapolation method. The results were compared on different grid
sizes as well as with the existing results for symmetric flow of Newtonian
fluids. The comparisons were satisfactory. The microrotation effects on the
splitter plate were significantly high as compared to other locations of the
channel. This highest value for the asymmetric channel was higher in magnitude
as compared to for the symmetric one. Furthermore, the proclivity of rotation
of aciculate elements of the fluid about their centroids rises if either the
Reynolds' number increases or/and the distance between the upper and splitter
plates decreases.


title:
Matrix Factorization-Based Clustering Of Image Features For
  Bandwidth-Constrained Information Retrieval

abstract:
  We consider the problem of accurately and efficiently querying a remote
server to retrieve information about images captured by a mobile device. In
addition to reduced transmission overhead and computational complexity, the
retrieval protocol should be robust to variations in the image acquisition
process, such as translation, rotation, scaling, and sensor-related
differences. We propose to extract scale-invariant image features and then
perform clustering to reduce the number of features needed for image matching.
Principal Component Analysis (PCA) and Non-negative Matrix Factorization (NMF)
are investigated as candidate clustering approaches. The image matching
complexity at the database server is quadratic in the (small) number of
clusters, not in the (very large) number of image features. We employ an
image-dependent information content metric to approximate the model order,
i.e., the number of clusters, needed for accurate matching, which is preferable
to setting the model order using trial and error. We show how to combine the
hypotheses provided by PCA and NMF factor loadings, thereby obtaining more
accurate retrieval than using either approach alone. In experiments on a
database of urban images, we obtain a top-1 retrieval accuracy of 89% and a
top-3 accuracy of 92.5%.


title: Low Rank Approximation in $G_0W_0$ Approximation

abstract:
  The single particle energies obtained in a Kohn--Sham density functional
theory (DFT) calculation are generally known to be poor approximations to
electron excitation energies that are measured in transport, tunneling and
spectroscopic experiments such as photo-emission spectroscopy. The correction
to these energies can be obtained from the poles of a single particle Green's
function derived from a many-body perturbation theory. From a computational
perspective, the accuracy and efficiency of such an approach depends on how a
self energy term that properly accounts for dynamic screening of electrons is
approximated. The $G_0W_0$ approximation is a widely used technique in which
the self energy is expressed as the convolution of a non-interacting Green's
function ($G_0$) and a screened Coulomb interaction ($W_0$) in the frequency
domain. The computational cost associated with such a convolution is high due
to the high complexity of evaluating $W_0$ at multiple frequencies. In this
paper, we discuss how the cost of $G_0W_0$ calculation can be reduced by
constructing a low rank approximation to the frequency dependent part of $W_0$.
In particular, we examine the effect of such a low rank approximation on the
accuracy of the $G_0W_0$ approximation. We also discuss how the numerical
convolution of $G_0$ and $W_0$ can be evaluated efficiently and accurately by
using a contour deformation technique with an appropriate choice of the
contour.


title: Nominal LCF: A Language for Generic Proof

abstract:
  The syntax and semantics of user-supplied hypothesis names in tactic
languages is a thorny problem, because the binding structure of a proof is a
function of the goal at which a tactic script is executed. We contribute a new
language to deal with the dynamic and interactive character of names in tactic
scripts called Nominal LCF, and endow it with a denotational semantics in
dI-domains. A large fragment of Nominal LCF has already been implemented and
used to great effect in the new RedPRL proof assistant.


title: Achieving translational symmetry in trapped cold ion rings

abstract:
  Spontaneous symmetry breaking is a universal concept throughout science. For
instance, the Landau-Ginzburg paradigm of translational symmetry breaking
underlies the classification of nearly all quantum phases of matter and
explains the emergence of crystals, insulators, and superconductors. Usually,
the consequences of translational invariance are studied in large systems to
suppress edge effects which cause undesired symmetry breaking. While this
approach works for investigating global properties, studies of local
observables and their correlations require access and control of the individual
constituents. Periodic boundary conditions, on the other hand, could allow for
translational symmetry in small systems where single particle control is
achievable. Here, we crystallize up to fifteen 40Ca+ ions in a microscopic ring
with inherent periodic boundary conditions. We show the ring's translational
symmetry is preserved at millikelvin temperatures by delocalizing the Doppler
laser cooled ions. This establishes an upper bound for undesired symmetry
breaking at a level where quantum control becomes feasible. These findings pave
the way towards studying quantum many-body physics with translational symmetry
at the single particle level in a variety of disciplines from simulation of
Hawking radiation to exploration of quantum phase transitions.


title:
New Approaches to Identify Gene-by-Gene Interactions in Genome Wide
  Association Studies

abstract:
  Genetic variants identified to date by genome-wide association studies only
explain a small fraction of total heritability. Gene-by-gene interaction is one
important potential source of unexplained heritability. In the first part of
this dissertation, a novel approach to detect such interactions is proposed.
This approach utilizes penalized regression and sparse estimation principles,
and incorporates outside biological knowledge through a network-based penalty.
The method is tested on simulated data under various scenarios. Simulations
show that with reasonable outside biological knowledge, the new method performs
noticeably better than current stage-wise strategies, especially when the
marginal strength of main effects is weak.
  The proposed method is designed for single-cohort analyses. However, it is
generally acknowledged that only multi-cohort analyses have sufficient power to
uncover genes and gene-by-gene interactions with moderate effects on traits,
such as likely underlie complex diseases. Multi-cohort, meta-analysis
approaches for penalized regressions are developed and investigated in the
second part of this dissertation. Specifically, I propose two different ways of
utilizing data-splitting principles in multi-cohort settings and develop three
procedures to conduct meta-analysis. Using the method developed in the first
part of this dissertation as an example of penalized regressions, three
proposed meta-analysis procedures are compared to mega-analysis using a
simulation study. The results suggest that the best approach is to split the
participating cohorts into two groups.
  In the last part of this dissertation, the novel method developed in the
first part is applied to the Framingham Heart Study measures on total plasma
Immunoglobulin E (IgE) concentrations, C-reactive protein levels, and Fasting
Glucose.


title: 3D Dirac cone carrier dynamics in Na3Bi and Cd3As2

abstract:
  Optical measurements and band structure calculations are reported on 3D Dirac
materials. The electronic properties associated with the Dirac cone are
identified in the reflectivity spectra of Cd$_3$As$_2$ and Na$_3$Bi single
crystals. In Na$_3$Bi, the plasma edge is found to be strongly temperature
dependent due to thermally excited free carriers in the Dirac cone. The thermal
behavior provides an estimate of the Fermi level $E_F=25$ meV and the z-axis
Fermi velocity $v_z = 0.3 \text{ eV} \AA$ associated with the heavy bismuth
Dirac band. At high energies above the $\Gamma$-point Lifshitz gap energy, a
frequency and temperature independent $\epsilon_2$ indicative of Dirac cone
interband transitions translates into an ab-plane Fermi velocity of $3 \text{
eV} \AA$. The observed number of IR phonons rules out the
$\text{P}6_3\text{/mmc}$ space group symmetry but is consistent with the
$\text{P}\bar{3}\text{c}1$ candidate symmetry. A plasmaron excitation is
discovered near the plasmon energy that persists over a broad range of
temperature. The optical signature of the large joint density of states arising
from saddle points at $\Gamma$ is strongly suppressed in Na$_3$Bi consistent
with band structure calculations that show the dipole transition matrix
elements to be weak due to the very small s-orbital character of the Dirac
bands. In Cd$_3$As$_2$, a distinctive peak in reflectivity due to the
logarithmic divergence in $\epsilon_1$ expected at the onset of Dirac cone
interband transitions is identified. The center frequency of the peak shifts
with temperature quantitatively consistent with a linear dispersion and a
carrier density of $n=1.3\times10^{17}\text{ cm}^{-3}$. The peak width gives a
measure of the Fermi velocity anisotropy of $10\%$, indicating a nearly
spherical Fermi surface. The lineshape gives an upper bound estimate of 7 meV
for the potential fluctuation energy scale.


title:
Gravitational-Wave Background from Binary Mergers and Metallicity
  Evolution of Galaxies

abstract:
  The cosmological evolution of the binary black hole (BH) merger rate and the
energy density of the gravitational-wave (GW) background are investigated. To
evaluate the redshift dependence of the BH formation rate, BHs are assumed to
originate from low-metallicity stars, and the relations between the star
formation rate, metallicity and stellar mass of galaxies are combined with the
stellar mass function at each redshift. As a result, it is found that when the
energy density of the GW background is scaled with the merger rate at the local
Universe, the scaling factor does not depend on the critical metallicity for
the formation of BHs. Also taking into account the merger of binary neutron
stars, a simple formula to express the energy spectrum of the GW background is
constructed for the inspiral phase. The relation between the local merger rate
and the energy density of the GW background will be examined by future GW
observations.

categories: astro-ph.HE astro-ph.CO astro-ph.GA gr-qc


title:
Unified Error Rates Analysis of MIMO Space-Time Block Codes over
  Generalized Shadowed {\kappa}-{\mu} and {\eta}-{\mu} Fading and AWGGN

abstract:
  This paper presents a novel unified performance analysis of Space-Time Block
Codes (STBCs) operating in the Multiple Input Multiple Output (MIMO) network
and subjected to generalized shadowed fading and noise scenarios. Specifically,
we derive novel, simple and accurate average bit error rates (ABER) expressions
for coherent modulation schemes in the generalized {\eta}-{\mu} and shadowed
{\kappa}-{\mu} fading channels. The noise in the network is assumed to be
modeled by the additive white generalized Gaussian noise (AWGGN), which
encompasses the Laplacian and the Gaussian noise environments as special cases.
The result obviates the need to re-derive the error rates for MIMO STBC systems
under many multipath fading and noise models, while avoiding
computationally-expensive expressions. Published results from the literature as
well as numerical simulations corroborate the accuracy of our derived
generalized expressions.


title:
Persistence of slow dynamics in Tb(OETAP)$_2$ single molecule magnets
  embedded in conducting polymers

abstract:
  The spin dynamics of Tb(OETAP)$_2$ single ion magnets was investigated by
means of muon spin resonance ($\mu$SR) both in the bulk material as well as
when the system is embedded into PEDOT:PSS polymer conductor. The
characteristic spin fluctuation time is characterized by a high temperature
activated trend, with an energy barrier around 320 K, and by a low temperature
tunneling regime. When the single ion magnet is embedded into the polymer the
energy barrier only slightly decreases and the fluctuation time remains of the
same order of magnitude even at low temperature. This finding shows that these
single molecule magnets preserve their characteristics which, if combined with
those of the conducting polymer, result in a hybrid material of potential
interest for organic spintronics.


title:
Time-Sliced Perturbation Theory II: Baryon Acoustic Oscillations and
  Infrared Resummation

abstract:
  We use time-sliced perturbation theory (TSPT) to give an accurate description
of the infrared non-linear effects affecting the baryonic acoustic oscillations
(BAO) present in the distribution of matter at very large scales. In TSPT this
can be done via a systematic resummation that has a simple diagrammatic
representation and does not involve uncontrollable approximations. We discuss
the power counting rules and derive explicit expressions for the resummed
matter power spectrum up to next-to leading order and the bispectrum at the
leading order. The two-point correlation function agrees well with N-body data
at BAO scales. The systematic approach also allows to reliably assess the shift
of the baryon acoustic peak due to non-linear effects.


title:
On Improving Informativity and Grammaticality for Multi-Sentence
  Compression

abstract:
  Multi Sentence Compression (MSC) is of great value to many real world
applications, such as guided microblog summarization, opinion summarization and
newswire summarization. Recently, word graph-based approaches have been
proposed and become popular in MSC. Their key assumption is that redundancy
among a set of related sentences provides a reliable way to generate
informative and grammatical sentences. In this paper, we propose an effective
approach to enhance the word graph-based MSC and tackle the issue that most of
the state-of-the-art MSC approaches are confronted with: i.e., improving both
informativity and grammaticality at the same time. Our approach consists of
three main components: (1) a merging method based on Multiword Expressions
(MWE); (2) a mapping strategy based on synonymy between words; (3) a re-ranking
step to identify the best compression candidates generated using a POS-based
language model (POS-LM). We demonstrate the effectiveness of this novel
approach using a dataset made of clusters of English newswire sentences. The
observed improvements on informativity and grammaticality of the generated
compressions show that our approach is superior to state-of-the-art MSC
methods.