  As photodisintegration of deuterons mimics the disintegration of deuterons by
neutrinos, the accurate measurement of the radioactivity from thorium and
uranium decay chains in the heavy water in the Sudbury Neutrino Observatory
(SNO) is essential for the determination of the total solar neutrino flux. A
radium assay technique of the required sensitivity is described that uses
hydrous titanium oxide adsorbent on a filtration membrane together with a
beta-alpha delayed coincidence counting system. For a 200 tonne assay the
detection limit for 232Th is a concentration of 3 x 10^(-16) g Th/g water and
for 238U of 3 x 10^(-16) g U/g water. Results of assays of both the heavy and
light water carried out during the first two years of data collection of SNO
are presented.


  Social media enabled a direct path from producer to consumer of contents
changing the way users get informed, debate, and shape their worldviews. Such a
{\em disintermediation} weakened consensus on social relevant issues in favor
of rumors, mistrust, and fomented conspiracy thinking -- e.g., chem-trails
inducing global warming, the link between vaccines and autism, or the New World
Order conspiracy.
  In this work, we study through a thorough quantitative analysis how different
conspiracy topics are consumed in the Italian Facebook. By means of a
semi-automatic topic extraction strategy, we show that the most discussed
contents semantically refer to four specific categories: {\em environment},
{\em diet}, {\em health}, and {\em geopolitics}. We find similar patterns by
comparing users activity (likes and comments) on posts belonging to different
semantic categories. However, if we focus on the lifetime -- i.e., the distance
in time between the first and the last comment for each user -- we notice a
remarkable difference within narratives -- e.g., users polarized on geopolitics
are more persistent in commenting, whereas the less persistent are those
focused on diet related topics. Finally, we model users mobility across various
topics finding that the more a user is active, the more he is likely to join
all topics. Once inside a conspiracy narrative users tend to embrace the
overall corpus.


  The assumption that an AEC is tame is a powerful assumption permitting
development of stability theory for AECs with the amalgamation property. Lately
several upward categoricity theorems were discovered where tameness replaces
strong set-theoretic assumptions.
  We present in this article two sufficient conditions for tameness, both in
form of strong amalgamation properties that occur in nature. One of them was
used recently to prove that several Hrushovski classes are tame.
  This is done by introducing the property of weak $(\mu,n)$-uniqueness which
makes sense for all AECs (unlike Shelah's original property) and derive it from
the assumption that weak $(\LS(\K),n)$-uniqueness, $(\LS(\K),n)$-symmetry and
$(\LS(\K),n)$-existence properties hold for all $n<\omega$. The conjunction of
these three properties we call \emph{excellence}, unlike \cite{Sh 87b} we do
not require the very strong $(\LS(\K),n)$-uniqueness, nor we assume that the
members of $\K$ are atomic models of a countable first order theory. We also
work in a more general context than Shelah's good frames.


  We obtain an asymptotically sharp error bound in the classical
Sudakov-Fernique comparison inequality for finite collections of gaussian
random variables. Our proof is short and self-contained, and gives an easy
alternative argument for the classical inequality, extended to the case of
non-centered processes.


  Designing for rotational stability can dramatically affect the geometry of a
space station. If improperly designed, the rotating station could end up
catastrophically tumbling end-over-end. Active stabilization can address this
problem; however, designing the station with passive rotation stability
provides a lower-cost solution. This paper presents passive rotational
stability guidelines for four space station geometries. Station stability is
first analyzed with thin-shell and thick-shell models. Stability is also
analyzed with models of the station's major constituent parts, including outer
shells, spokes, floors, air, and shuttle bays.


  The catalog of gravitational-wave events is growing, and so are our hopes of
constraining the underlying astrophysics of stellar-mass black-hole mergers by
inferring the distributions of, e.g., masses and spins. While conventional
analyses parametrize this population with simple phenomenological models, we
propose an emulation-based approach that can compare astrophysical simulations
against gravitational-wave data. We combine state-of-the-art deep-learning
techniques with hierarchical Bayesian inference and exploit our approach to
constrain the properties of repeated black-hole mergers from the
gravitational-wave events in the most recent LIGO/Virgo catalog. Deep neural
networks allow us to (i) construct a flexible single-channel population model
that accurately emulates simple parametrized numerical simulations of
hierarchical mergers, (ii) estimate selection effects, and (iii) recover the
branching ratios of repeated-merger generations. Among our results, we find the
following: The distribution of host-environment escape speeds favors values
less than $100~\mathrm{km\,s^{-1}}$ but is relatively flat, with around $37\%$
of first-generation mergers retained in their host environments;
first-generation black holes are born with a maximum mass that is compatible
with current estimates from pair-instability supernovae; there is multimodal
substructure in both the mass and spin distributions, which, in our model, can
be explained by repeated mergers; and binaries with a higher-generation
component make up at least $14\%$ of the underlying population. Though these
results are inferred through emulation of a simplified model, the deep-learning
pipeline we present is readily applicable to realistic astrophysical
simulations


  A new mechanism of longitudinal confinement of optical energy via coupled
plasmon modes is proposed in chains of noble metal nanoparticles embedded in a
graded dielectric medium, which is analogous to the confinement of electrons in
semiconductor quantum wells. In these systems, one can control the transmission
of optical energy by varying the graded refractive index of the host medium or
the separation between the nanoparticles to realize the photonic analogue of
electronic transistors. Possible passband tunability by nanoparticle spacing
and modulation of the refractive index in the host medium have been presented
explicitly and compared favorably with numerical calculations.


  We use first-principles calculations to extract two essential microscopic
parameters, the charge-transfer energy and the inter-cell oxygen-oxygen
hopping, which correlate with the maximum superconducting transition
temperature $\Tcmax$ across the cuprates. We explore the superconducting state
in the three-band model of the copper-oxygen planes using cluster Dynamical
Mean-Field Theory. We find that the variation in the charge-transfer energy
largely accounts for the empirical trend in $\Tcmax$, resolving a long-standing
contradiction with theoretical calculations.


  We calculate, in a model, the beam spin asymmetry in semi-inclusive jet
production in deep inelastic scattering. This twist-3, $T$-odd observable is
non-zero due to final state strong interactions. With reasonable choices for
the parameters, one finds an asymmetry of several percent, about the size seen
experimentally. We present the result both as an explicit asymmetry calculation
and as a model calculation of the new transverse-momentum dependent
distribution function $g^\perp$.


  In exploratory data analysis, analysts often have a need to identify
histograms that possess a specific distribution, among a large class of
candidate histograms, e.g., find countries whose income distribution is most
similar to that of Greece. This distribution could be a new one that the user
is curious about, or a known distribution from an existing histogram
visualization. At present, this process of identification is brute-force,
requiring the manual generation and evaluation of a large number of histograms.
We present FastMatch: an end-to-end approach for interactively retrieving the
histogram visualizations most similar to a user-specified target, from a large
collection of histograms. The primary technical contribution underlying
FastMatch is a probabilistic algorithm, HistSim, a theoretically sound
sampling-based approach to identify the top-$k$ closest histograms under
$\ell_1$ distance. While HistSim can be used independently, within FastMatch we
couple HistSim with a novel system architecture that is aware of practical
considerations, employing asynchronous block-based sampling policies, building
on lightweight sampling engines developed in recent work. FastMatch obtains
near-perfect accuracy with up to $35\times$ speedup over approaches that do not
use sampling on several real-world datasets.


  This paper introduces EQShapelets (EarthQuake Shapelets) a time-series
shape-based approach embedded in machine learning to autonomously detect
earthquakes. It promises to overcome the challenges in the field of seismology
related to automated detection and cataloging of earthquakes. EQShapelets are
amplitude and phase-independent, i.e., their detection sensitivity is
irrespective of the magnitude of the earthquake and the time of occurrence.
They are also robust to noise and other spurious signals. The detection
capability of EQShapelets is tested on one week of continuous seismic data
provided by the Northern California Seismic Network (NCSN) obtained from a
station in central California near the Calaveras Fault. EQShapelets combined
with a Random Forest classifier, detected all of the cataloged earthquakes and
281 uncataloged events with lower false detection rate thus offering a better
performance than autocorrelation and FAST algorithms. The primary advantage of
EQShapelets over competing methods is the interpretability and insight it
offers. Shape-based approaches are intuitive, visually meaningful and offers
immediate insight into the problem domain that goes beyond their use in
accurate detection. EQShapelets, if implemented at a large scale, can
significantly reduce catalog completeness magnitudes and can serve as an
effective tool for near real-time earthquake monitoring and cataloging.


  This is an extended write-up of a talk given in April, 1993 in honor of Raoul
Bott's 70th birthday. We first illustrate how some traditional topological and
geometric invariants obey ``gluing laws'' inspired by those in classical and
quantum field theory. Here we discuss characteristic numbers, particularly the
Euler number of a complex line bundle over an oriented surface. In the second
part of the paper we show how path integrals give rise to invariants which obey
gluing laws. The argument is formal in general, but for a particular example of
invariants related to finite groups it is rigorous. In that ``toy model'' we
show how to go further and generalize the path integral to obtain more exotic
gluing laws. This idea was used--at least in this toy model--to directly
construct quantum groups from 3 dimensional Chern-Simons invariants.


  Rationales in the form of manually annotated input spans usually serve as
ground truth when evaluating explainability methods in NLP. They are, however,
time-consuming and often biased by the annotation process. In this paper, we
debate whether human gaze, in the form of webcam-based eye-tracking recordings,
poses a valid alternative when evaluating importance scores. We evaluate the
additional information provided by gaze data, such as total reading times, gaze
entropy, and decoding accuracy with respect to human rationale annotations. We
compare WebQAmGaze, a multilingual dataset for information-seeking QA, with
attention and explainability-based importance scores for 4 different
multilingual Transformer-based language models (mBERT, distil-mBERT, XLMR, and
XLMR-L) and 3 languages (English, Spanish, and German). Our pipeline can easily
be applied to other tasks and languages. Our findings suggest that gaze data
offers valuable linguistic insights that could be leveraged to infer task
difficulty and further show a comparable ranking of explainability methods to
that of human rationales.


  Adopting a mean-field description for a two-component atomic Bose-Einstein
condensate, we study the stat- ics and dynamics of dark-bright solitons in the
presence of localized impurities. We use adiabatic perturbation theory to
derive an equation of motion for the dark-bright soliton center. We show that,
counter-intuitively, an attractive (repulsive) delta-like impurity, acting
solely on the bright soliton component, induces an effective localized barrier
(well) in the effective potential felt by the soliton; this way, dark-bright
solitons are reflected from (transmitted through) attractive (repulsive)
impurities. Our analytical results for the small-amplitude oscil- lations of
solitons are found to be in good agreement with results obtained via a
Bogoliubov-de Gennes analysis and direct numerical simulations.


  We use our model for the formation and evolution of galaxies within a
two-phase galaxy formation scenario, showing that the high-redshift domain
typically supports the growth of spheroidal systems, whereas at low redshifts
the predominant baryonic growth mechanism is quiescent and may therefore
support the growth of a disc structure. Under this framework we investigate the
evolving galaxy population by comparing key observations at both low and
high-redshifts, finding generally good agreement. By analysing the evolutionary
properties of this model, we are able to recreate several features of the
evolving galaxy population with redshift, naturally reproducing number counts
of massive star-forming galaxies at high redshifts, along with the galaxy
scaling relations, star formation rate density and evolution of the stellar
mass function. Building upon these encouraging agreements, we make model
predictions that can be tested by future observations. In particular, we
present the expected evolution to z=2 of the super-massive black hole mass
function, and we show that the gas fraction in galaxies should decrease with
increasing redshift in a mass, with more and more evolution going to higher and
higher masses. Also, the characteristic transition mass from disc to bulge
dominated system should decrease with increasing redshift.


  Based on published data, we have produced a sample of 256 radio sources whose
trigonometric parallaxes and proper motions were measured by VLBI. This sample
contains Galactic masers associated with massive protostars and stars in active
star-forming regions. It also includes young low-mass stars from the Gould Belt
region whose radio observations were performed in continuum. Based on this,
most complete sample of sources to date, we have estimated the velocities
$(U,V,W)_\odot$ and the parameters of the angular velocity of Galactic rotation
$\Omega_0, \Omega^{(1)}_0, ... , \Omega^{(4)}_0$ and obtained a new estimate of
the distance fromthe Sun to the Galactic center, $R_0=8.15^{+0.04}_{-0.20}$
kpc. The parameters of the Galactic spiral density wave have been found from
the series of radial, $V_R$, and residual tangential, $\Delta V_{circ}$,
velocities of stars. The amplitudes of the radial and tangential velocity
perturbations are $f_R=7.0\pm0.9$ km s$^{-1}$ and $f_\theta=3.8\pm1.1$ km
s$^{-1}$, the perturbation wavelengths are $\lambda_R=2.3\pm0.2$ kpc and
$\lambda_\theta=2.0\pm0.4$ kpc, and the Sun's phases in the spiral density wave
are $(\chi_\odot)_R=-163^\circ\pm9^\circ$ and
$(\chi_\odot)_\theta=-137^\circ\pm10^\circ$ for the adopted four-armed spiral
pattern.


  The nonlinear Schr\"odinger and the Schr\"odinger-Newton equations model many
phenomena in various fields. Here, we perform an extensive numerical comparison
between splitting methods (often employed to numerically solve these equations)
and the integrating factor technique, also called Lawson method. Indeed, the
latter is known to perform very well for the nonlinear Schr\"odinger equation,
but has not been thoroughly investigated for the Schr\"odinger-Newton equation.
Comparisons are made in one and two spatial dimensions, exploring different
boundary conditions and parameters values. We show that for the short range
potential of the nonlinear Schr\"odinger equation, the integrating factor
technique performs better than splitting algorithms, while, for the long range
potential of the Schr\"odinger-Newton equation, it depends on the particular
system considered.


  We use the unprecedented resolution and depth of the JWST NIRCam Early
Release Observations at 1-5 $\mu$m to study the stellar mass, age, and
metallicity of compact star clusters in the neighborhood of the host galaxies
in the SMACS J0723.3-7327 galaxy cluster field at z = 0.39. The measured colors
of these star clusters show a similar distribution as quiescent galaxies at the
same redshift, but are >3 magnitudes fainter than the current depths of
wide-field galaxy survey. The star clusters are unresolved in the NIRCam/F150W
data suggesting sizes smaller than 50pc. This is significantly smaller than
star forming clumps or dwarf galaxies in local galaxies. From fitting their
photometry with simple stellar population (SSP) models, we find stellar
metallicities consistent with 0.2-0.3 $Z_{\odot}$ and ages of
$1.5^{+0.5}_{-0.5}$ Gyrs. We rule out metallicities <0.2 $Z_{\odot}$ and
solar/super-solar at 4$\sigma$ significance. Assuming mass-to-light ratios
obtained from the best-fit SSPs, we estimate stellar masses of
$2.4^{+3.0}_{-1.5}\times10^6$ M$_{\odot}$. These are between average masses of
local globular clusters and dwarf galaxies. Our analysis suggests middle-aged
globulars with relatively recent formation times at z=0.5-0.7, which could have
been subsequently stripped away from their host galaxies due to interactions in
the cluster environment, or formed in cold flows onto the cluster core.
However, we cannot rule out these objects being compact cores of stripped dwarf
galaxies.


  In this paper, physics-informed neural network (PINN) based on
characteristic-based split (CBS) is proposed, which can be used to solve the
time-dependent Navier-Stokes equations (N-S equations). In this method, The
output parameters and corresponding losses are separated, so the weights
between output parameters are not considered. Not all partial derivatives
participate in gradient backpropagation, and the remaining terms will be
reused.Therefore, compared with traditional PINN, this method is a rapid
version. Here, labeled data, physical constraints and network outputs are
regarded as priori information, and the residuals of the N-S equations are
regarded as posteriori information. So this method can deal with both
data-driven and data-free problems. As a result, it can solve the special form
of compressible N-S equations -- -Shallow-Water equations, and incompressible
N-S equations. As boundary conditions are known, this method only needs the
flow field information at a certain time to restore the past and future flow
field information. We solve the progress of a solitary wave onto a shelving
beach and the dispersion of the hot water in the flow, which show this method's
potential in the marine engineering. We also use incompressible equations with
exact solutions to prove this method's correctness and universality. We find
that PINN needs more strict boundary conditions to solve the N-S equation,
because it has no computational boundary compared with the finite element
method.


  The unexpected finding of a strong magnetic field dependence of the
dielectric properties of insulating glasses at very low temperatures has been a
puzzling problem since its discovery. Several attempts have been made to
explain this striking phenomenon. In order to obtain information on the origin
of the magnetic field effects we have studied coherent properties of atomic
tunneling systems in glasses by polarization echo experiments in magnetic
fields. Our results clearly favor a model based on the assumption that nuclear
quadrupoles play a crucial role for the observed magnetic field dependence.


  We study the path behavior of the symmetric walk on some special comb-type
subsets of ${\mathbb Z}^2$ which are obtained from ${\mathbb Z}^2$ by
generalizing the comb having finitely many horizontal lines instead of one.


  Let \{M_{r,s}\}_{0< r < p, 0< s < p'} be the irreducible Virasoro modules in
the $(p,p')$-minimal series. In our previous paper, we have constructed a
monomial basis of \oplus_{r=1}^{p-1}M_{r,s} in the case of $1<p'/p<2$. By
`monomials' we mean vectors of the form
\phi^{(r_L,r_{L-1})}_{-n_L}...\phi^{(r_1,r_{0})}_{-n_1} |r_0,s >, where
\phi_{-n}^{(r',r)} are the Fourier components of the (2,1)-primary field
mapping M_{r,s} to M_{r',s}, and |r_0,s > is the highest weight vector of
M_{r_0,s}. In this article, for all p<p' with p>2 and s=1, we describe a subset
of such monomials which conjecturally forms a basis of
\oplus_{r=1}^{p-1}M_{r,1}. We prove that the character of the combinatorial set
labeling these monomials coincides with the character of the corresponding
Virasoro module. We also verify the conjecture in the case of p=3.


  The cyber-threat landscape has evolved tremendously in recent years, with new
threat variants emerging daily, and large-scale coordinated campaigns becoming
more prevalent. In this study, we propose CELEST (CollaborativE LEarning for
Scalable Threat detection, a federated machine learning framework for global
threat detection over HTTP, which is one of the most commonly used protocols
for malware dissemination and communication. CELEST leverages federated
learning in order to collaboratively train a global model across multiple
clients who keep their data locally, thus providing increased privacy and
confidentiality assurances. Through a novel active learning component
integrated with the federated learning technique, our system continuously
discovers and learns the behavior of new, evolving, and globally-coordinated
cyber threats. We show that CELEST is able to expose attacks that are largely
invisible to individual organizations. For instance, in one challenging attack
scenario with data exfiltration malware, the global model achieves a three-fold
increase in Precision-Recall AUC compared to the local model. We also design a
poisoning detection and mitigation method, DTrust, specifically designed for
federated learning in the collaborative threat detection domain. DTrust
successfully detects poisoning clients using the feedback from participating
clients to investigate and remove them from the training process. We deploy
CELEST on two university networks and show that it is able to detect the
malicious HTTP communication with high precision and low false positive rates.
Furthermore, during its deployment, CELEST detected a set of previously unknown
42 malicious URLs and 20 malicious domains in one day, which were confirmed to
be malicious by VirusTotal.


  For a given finite index inclusion of conformal nets $\mathcal{B}\subset
\mathcal{A}$ and a group $G < \mathrm{Aut}(\mathcal{A}, \mathcal{B})$, we
consider the induction and the restriction procedures for $G$-twisted
representations. We define two induction procedures for $G$-twisted
representations, which generalize the $\alpha^{\pm}$-induction for DHR
endomorphisms. One is defined with the opposite braiding on the category of
$G$-twisted representations as in $\alpha^-$-induction. The other is also
defined with the braiding, but additionally with the $G$-equivariant structure
on the Q-system associated with $\mathcal{B}\subset \mathcal{A}$ and the action
of $G$. We derive some properties and formulas for these induced endomorphisms
in a similar way to the case of ordinary $\alpha$-induction. We also show the
version of $\alpha\sigma$-reciprocity formula for our setting.


  We revisit the orbital history of the Triangulum galaxy (M33) around the
Andromeda galaxy (M31) in view of the recent Gaia Data Release 2 proper motion
measurements for both Local Group galaxies. Earlier studies consider highly
idealised dynamical friction, but neglect the effects of dynamical mass loss.
We show the latter process to be important using mutually consistent orbit
integration and N-body simulations. Following this approach we find an orbital
solution that brings these galaxies to within ~50 kpc of each other in the
past, ~6.5 Gyr ago. We explore the implications of their interaction using an
N-body/hydrodynamical simulation with a focus on the origin of two prominent
features: 1) M31's Giant Stellar Stream; and 2) the M31-M33 HI filament. We
find that the tidal interaction does not produce a structure reminiscent of the
stellar stream that survives up to the present day. In contrast, the M31-M33 HI
filament is likely a fossil structure dating back to the time of the ancient
encounter between these galaxies. Similarly, the observed outer disc warp in
M33 may well be a relic of this past event. Our model suggests the presence of
a tidally induced gas envelope around these galaxies, and the existence of a
diffuse gas stream, the 'Triangulum stream', stretching for tens of kpc from
M33 away from M31. We anticipate upcoming observations with the recently
commissioned, Five-hundred-meter Aperture Spherical radio Telescope (FAST) that
will target the putative stream in its first years of operation.


  We present the procedures and results of the quality control tests for the
front-end optical link components in the ATLAS Liquid Argon Calorimeter Phase-1
upgrade. The components include a Vertical-Cavity Surface-Emitting Laser
(VCSEL) driver ASIC LOCld, custom optical transmitter/transceiver modules
MTx/MTRx, and a transmitter ASIC LOCx2. LOCld, MTx, and LOCx2 each contain two
channels with the same structure, while MTRx has a transmitter channel and a
receiver channel. Each channel is tested at 5.12 Gbps. A total of 5341 LOCld
chips, 3275 MTx modules, 797 MTRx modules, and 3198 LOCx2 chips are qualified.
The yields are 73.9%, 98.0%, 98.4%, and 61.9% for LOCld, LOCx2, MTx, and MTRx,
respectively.


  In this work we introduce a time- and memory-efficient method for structured
prediction that couples neuron decisions across both space at time. We show
that we are able to perform exact and efficient inference on a densely
connected spatio-temporal graph by capitalizing on recent advances on deep
Gaussian Conditional Random Fields (GCRFs). Our method, called VideoGCRF is (a)
efficient, (b) has a unique global minimum, and (c) can be trained end-to-end
alongside contemporary deep networks for video understanding. We experiment
with multiple connectivity patterns in the temporal domain, and present
empirical improvements over strong baselines on the tasks of both semantic and
instance segmentation of videos.


  The possible low-frequency radio emission from the progenitors of gamma ray
bursts can experience a delay from tens of seconds to hours on the way to the
observer due to the dispersion in galactic and extragalactic plasma, and thus
reach the observer as a radio afterglow of the burst. This opens a unique
possibility (peculiar "Time Machine") of seeing what happened in that place
before the catastrophe.


  We show that there exists a 1-parameter family of positive-definite and
conserved energy functionals for axially symmetric Newman-Penrose-Maxwell
scalars on the maximal spacelike hypersurfaces in the exterior of Kerr black
holes. It is also shown that the Poisson bracket within this 1-parameter family
of energies vanishes on the maximal hypersurfaces.


  We analyze the influence of phonons on the d-wave pairing instability in the
Hubbard model on the two-dimensional square lattice at weak to moderate
interaction U, using a functional renormalization group scheme with
frequency-dependent interaction vertices. As measured by the pairing scale, the
B1g buckling mode enhances the pairing, while other phonon modes decrease the
pairing. When various phonon modes are included together, the net effect on the
scale is small. However, in situations where d-wave superconductivity and other
tendencies, e.g. antiferromagnetism, are closely competing, the combined effect
of different phonons may be able to tip the balance towards pairing.


  We observed two fields near M32 with the Advanced Camera for Surveys/High
Resolution Channel (ACS/HRC) on board the Hubble Space Telescope (HST). The
main field, F1, is 1.8 arcmin from the center of M32; the second field, F2,
constrains the M31 background, and is 5.4 arcmin distant. Each field was
observed for 16-orbits in each of the F435W (narrow B) and F555W (narrow V)
filters. The duration of the observations allowed RR Lyrae stars and other
short-period variables to be detected. A population of RR Lyrae stars
determined to belong to M32 would prove the existence of an ancient population
in that galaxy, a subject of some debate. We detected 17 RR Lyrae variables in
F1 and 14 in F2. A 1-sigma upper limit of 6 RR Lyrae variables belonging to M32
is inferred from these two fields alone. Use of our two ACS/WFC parallel fields
provides better constraints on the M31 background, however, and implies that
$7_{-3}^{+4}$ (68 % confidence interval) RR Lyrae variables in F1 belong to
M32. We have therefore found evidence for an ancient population in M32. It
seems to be nearly indistinguishable from the ancient population of M31. The RR
Lyrae stars in the F1 and F2 fields have indistinguishable mean V-band
magnitudes, mean periods, distributions in the Bailey diagram and ratios of RRc
to RR(tot) types. However, the color distributions in the two fields are
different, with a population of red RRab variables in F1 not seen in F2. We
suggest that these might be identified with the detected M32 RR Lyrae
population, but the small number of stars rules out a definitive claim.


  We model a one-dimensional shock-tube using smoothed particle hydrodynamics
and investigate the consequences of having finite shock-width in numerical
simulations. We investigate the cooling of gas during passage through the shock
for different cooling regimes. For a shock temperature of 10^5K, the maximum
temperature of the gas is much reduced and the cooling time was reduced by a
factor of 2. At lower temperatures, we are especially interested in the
production of molecular Hydrogen and so we follow the ionization level and H_2
abundance across the shock. This regime is particularly relevent to simulations
of primordial galaxy formation for halos in which the virial temperature of the
galaxy is sufficiently high to partially re-ionize the gas. The effect of
in-shock cooling is substantial: the maximum temperature the gas reaches
compared to the theoretical temperature was found to vary between 0.15 and 0.81
for the simulations performed. The downstream ionization level is reduced from
the theoretical level by a factor of between 2.4 and 12.5, and the resulting
H_2 abundance was found to be reduced to a fraction of 0.45 to 0.74 of its
theoretical value. At temperatures above 10^5K, radiative shocks are unstable
and will oscillate. We reproduce these oscillations and find good agreement
with the previous work of Chevalier and Imamura (1982), and Imamura, Wolff and
Durisen (1984). The effect of in-shock cooling in such shocks is difficult to
quantify, but is undoubtedly present.


  Local Linear embedding (LLE) is a popular dimension reduction method. In this
paper, we first show LLE with nonnegative constraint is equivalent to the
widely used Laplacian embedding. We further propose to iterate the two steps in
LLE repeatedly to improve the results. Thirdly, we relax the kNN constraint of
LLE and present a sparse similarity learning algorithm. The final Iterative LLE
combines these three improvements. Extensive experiment results show that
iterative LLE algorithm significantly improve both classification and
clustering results.


  Twisted kinks in the massless NJL$_2$ model interpolate between two distinct
vacua on the chiral circle. If one approaches the chiral limit from finite bare
fermion masses $m_0$, the vacuum is unique and twist cannot exist. This issue
is studied analytically in the non-relativistic limit, using a no-sea effective
theory. We conclude that even in the massless limit, the interpretation of the
twisted kink has to be revised. One has to attribute the fermion number of the
valence state to the twisted kink. Fermion density is spread out over the whole
space due to the massless pion field. The result can be pictured as a composite
of a twisted kink (carrying energy, but no fermion number) and a partial
winding of the chiral spiral (carrying fermion number, but no energy). This
solves at the same time the puzzle of missing baryons with fermion number
$N_f<N$ in the massless NJL$_2$ model.


  We construct Euclidean random fields $X$ over $\R^d$, by convoluting
generalized white noise $F$ with some integral kernels $G$, as $X=G* F$. We
study properties of Schwinger (or moment) functions of $X$. In particular, we
give a general equivalent formulation of the cluster property in terms of
truncated Schwinger functions which we then apply to the above fields. We
present a partial negative result on the reflection positivity of convoluted
generalized white noise.
  Furthermore, by representing the kernels $G_\a$ of the pseudo--differential
operators $(-\D + m^2_0)^{-\alpha}$ for $\alpha \in (0,1)$ and $m_0>0$ as
Laplace transforms we perform the analytic continuation of the (truncated)
Schwinger functions of $X=G_\alpha * F$, obtaining the corresponding
(truncated) Wightman distributions on Minkowski space which satisfy the
relativistic postulates on invariance, spectral property, locality and cluster
property.
  Finally we give some remarks on scattering theory for these models.


  We study the pseudoduality transformation on the symmetric space sigma
models. We switch the Lie group valued pseudoduality equations to Lie algebra
valued ones, which leads to an infinite number of pseudoduality equations. We
obtain an infinite number of conserved currents on the tangent bundle of the
pseudodual manifold. We show that there can be mixing of decomposed spaces with
each other, which leads to mixings of the following expressions. We obtain the
mixing forms of curvature relations and one loop renormalization group beta
functions by means of these currents.


  Autonomous robotic systems are complex, hybrid, and often safety-critical;
this makes their formal specification and verification uniquely challenging.
Though commonly used, testing and simulation alone are insufficient to ensure
the correctness of, or provide sufficient evidence for the certification of,
autonomous robotics. Formal methods for autonomous robotics has received some
attention in the literature, but no resource provides a current overview. This
paper systematically surveys the state-of-the-art in formal specification and
verification for autonomous robotics. Specially, it identifies and categorises
the challenges posed by, the formalisms aimed at, and the formal approaches for
the specification and verification of autonomous robotics.


  One-way-broadcast based flooding time synchronization algorithms are commonly
used in wireless sensor networks (WSNs). However, the packet delay and clock
drift pose challenges to accuracy, as they entail serious by-hop error
accumulation problems in the WSNs. To overcome it, a rapid flooding
multi-broadcast time synchronization with real-time delay compensation
(RDC-RMTS) is proposed in this paper. By using a rapid-flooding protocol,
flooding latency of the referenced time information is significantly reduced in
the RDC-RMTS. In addition, a new joint clock skew-offset maximum likelihood
estimation is developed to obtain the accurate clock parameter estimations, and
the real-time packet delay estimation. Moreover, an innovative implementation
of the RDC-RMTS is designed with an adaptive clock offset estimation. The
experimental results indicate that, the RDC-RMTS can easily reduce the variable
delay and significantly slow the growth of by-hop error accumulation. Thus, the
proposed RDC-RMTS can achieve accurate time synchronization in large-scale
complex WSNs.


  Relativistic time synchronization along closed integral lines maintains
magnetic flux quantization independently from gravitation. All Fermi-volume
electrons form time-averaged electromagnetic fields within rotating conductors,
while Fermi-surface superelectrons enable flux quantization in SQUID
experiments. Inertia is not related to instantaneous self-coherent states of
the distributed electric charge and, therefore, the Cooper pair mass can not be
measured in principle from magnetic flux quantization.


  Io's atmosphere is predominately SO2 sustained by a combination of volcanic
outgassing and sublimation. The loss from the atmosphere is the main mass
source for Jupiter's large magnetosphere. Previous studies attributed various
transient phenomena in Io's environment and Jupiter's magnetosphere to a sudden
change in the mass loss from the atmosphere supposedly triggered by a change in
volcanic activity. Since the gas in volcanic plumes does not escape directly,
such causal correlation would require a transient volcano-induced change in
atmospheric abundance, which has never been observed so far. Here we report
four observations of atmospheric SO2 and NaCl obtained with the IRAM NOEMA
interferometer. These observations are compared to measurements of volcanic hot
spots and Io's neutral and plasma environment. We find a stable NaCl column
density in Io's atmosphere. The SO2 column density derived for December 2016 is
about 30% lower compared to the period of March to April 2017. This increase in
SO2 from December 2016 to March 2017 might be related to increasing volcanic
activity observed at several sites in spring 2017, but the stability of the
volcanic trace gas NaCl and resulting decrease in NaCl/SO2 ratio do not support
this interpretation. Observed dimmings in both the sulfur ion torus and Na
neutral cloud suggest rather a decrease in mass loading in the period of
increasing SO2 abundance. The dimming Na brightness and stable atmospheric NaCl
furthermore dispute an earlier suggested positive correlation of the sodium
cloud and the hot spot activity at Loki Patara, which considerably increased in
this period. The environment of Io overall appears to be in a quiescent state,
preventing further conclusions. Only Jupiter's aurora morphology underwent
several short-term changes, which are apparently unrelated to Io's quiescent
environment or the relatively stable atmosphere.


  We study the holographic QCD in the hadronic medium by using the soft wall
model. We discuss the Hawking-Page transition between Reissner-Nordstr\"{o}m
AdS black hole and thermal charged AdS of which the geometries correspond to
deconfinement and confinement phases respectively. We also present the
numerical result of the vector and axial vector meson spectra depending on the
quark density.


  The wavelengths of the individual [O II] 2s22p3 2Do(5/2) - 2s22p3
2Po(1/2,3/2) 7320\AA and [O II] 2s22p3 2Do(3/2) - 2s22p3 2Po(1/2,3/2) 7330\AA
auroral doublet component lines have been measured directly in the nightglow
for the first time, from high resolution spectra obtained with the HIRES
spectrograph on the Keck I telescope at the W.M. Keck Observatory.
Specifically, we find 7320\AA and 7330\AA doublet splittings of
1.077$\pm$0.003\AA and 1.080$\pm$0.003\AA respectively, with the former
significantly larger than the often quoted and utilized value of 0.8\AA from
Moore (1949, Atomic Energy Levels, Vol 1), and in line with NIST (1.07\AA) as
well as more recent astrophysical observations of the lines in planetary
nebulae including 1.07\AA from DeRobertis, Osterbrock, & McKee
(1985,ApJ,293,459) and 1.09\AA from Barnett & McKeith (1988,MNRAS,234,241). Our
results suggest, however, that adjustments of +0.124\AA and +0.131\AA should be
made to current NIST wavelengths for the blue and red components of the 7320\AA
doublet respectively, while the wavelengths of the 7330\AA doublet components
are little changed from current NIST values. The observed intensity ratio of
7320\AA/7330\AA from these measurements agrees with the theoretical value
calculated under conditions of thermally populated 2Po levels.


  In this paper we investigate collision detection and avoidance in a vehicular
network of full duplex (FD) operating nodes. Each vehicle in this network
senses the energy level of the channel before and during its transmission. The
measured energy is compared against a dynamic threshold which is preset based
on the target detection probability, transmitter's power, sensing time and
self-interference cancellation (SIC) capability of the vehicles' on board units
(OBU). Probabilities of detection and false alarm, detection threshold before
and during transmission, and effect of residual self interference (SI) on these
metrics have been formulated. It is shown that the proposed scheme would
experience a shorter collision duration. Meanwhile, it also requires a minimum
SIC capability for acceptable operation, below which, system throughput would
be poor due to high false alarm probability. Numerical simulations verify the
accuracy of our analysis. They also illustrate that the proposed model perform
better than the fixed threshold strategy. A trade-off between half duplex (HD)
and FD has been found and the scheme would be applicable even if SIC capability
of OBUs is relatively poor, with no need for complicated and expensive devices
for future vehicular communication.


  The electron (anti-)neutrino component of the T2K neutrino beam constitutes
the largest background in the measurement of electron (anti-)neutrino
appearance at the far detector. The electron neutrino scattering is measured
directly with the T2K off-axis near detector, ND280. The selection of the
electron (anti-)neutrino events in the plastic scintillator target from both
neutrino and anti-neutrino mode beams is discussed in this paper. The flux
integrated single differential charged-current inclusive electron
(anti-)neutrino cross-sections, $d\sigma/dp$ and $d\sigma/d\cos(\theta)$, and
the total cross-sections in a limited phase-space in momentum and scattering
angle ($p > 300$ MeV/c and $\theta \leq 45^{\circ}$) are measured using a
binned maximum likelihood fit and compared to the neutrino Monte Carlo
generator predictions, resulting in good agreement.


  We theoretically investigate the properties of two interacting ultracold
highly magnetic atoms trapped in a one-dimensional harmonic potential. The
atoms interact via an anisotropic long-range dipole-dipole interaction, which
in one dimension effectively can be modeled by the contact interaction. We
investigate the interplay of the external magnetic field, the spin-spin
interaction, and the trapping potential and how they affect the magnetization
of the system. We show the role of indistinguishability and symmetries in the
dynamics by studying the time evolution of the observables that could be
measured experimentally. The presented model may depict the on-site interaction
of the extended Hubbard models, therefore giving a better understanding of the
fundamental building block of the respective many-body quantum simulators.


  Transferring a significant fraction of the magnetic flux from a dense cloud
core is essential in the star formation process. A ring-like structure produced
by magnetic flux loss has been predicted theoretically, but no observational
identification has been presented. We have performed ALMA observations of the
Class I protostar IRS 2 in the Corona Australis star-forming region and
resolved a distinctive gas ring in the C$^{18}$O ($J$ = 2-1) line emission. The
center of this gas ring is $\sim$5,000 au away from the protostar, with a
diameter of $\sim$7,000 au. The radial velocity of the gas is $\lesssim1$ km
s$^{-1}$ blueshifted from that of the protostar, with a possible expanding
feature judged from the velocity-field (moment 1) map and position-velocity
diagram. These features are either observationally new or have been discovered
but not discussed in depth because they are difficult to explain by
well-studied protostellar phenomena such as molecular outflows and accretion
streamers. A plausible interpretation is a magnetic wall created by the
advection of magnetic flux which is theoretically expected in the Class 0/I
phase during star formation as a removal mechanism of magnetic flux. Similar
structures reported in the other young stellar sources could likely be
candidates formed by the same mechanism, encouraging us to revisit the issue of
magnetic flux transport in the early stages of star formation from an
observational perspective.


  The starting point of this paper is a system described in form of a UML class
diagram where system states are characterized by OCL invariants and system
transitions are defined by OCL pre- and postconditions. The aim of our approach
is to assist the developer in learning about the consequences of the described
system states and transitions and about the formal implications of the
properties that are explicitly given. We propose to draw conclusions about the
stated constraints by translating the UML and OCL model into the algebraic
specification language and system Maude, which is based on rewrite logic. We
will concentrate in this paper on employing Maude's capabilities for state
search. Maude's state search offers the possibility to describe a start
configuration of the system and then explore all configurations reachable by
rewriting. The search can be adjusted by formulating requirements for the
allowed states and the allowed transitions.


  In the Dimension Embedded in Unified Symmetry (Adrian Sabin Popescu, D.E.U.S.
(Dimension Embedded in Unified Symmetry), p. 221-247, Ed. Cartea Universitara,
Bucuresti, ISBN 978-973-731-519-9 (arXiv:0704.2670) (2007)) book we made a
qualitative description of the way in which we can construct the Large Scale
Structure of the Universe from the knot-particle equivalence. Even that we are
limited by the lack of computational power implemented on a nonlinear
computational architecture needed to conduct this study to its finish, we are
still able to give the algorithm to be used in a future simulation, on a, let
say, quantum computer.


  We present experimental and theoretical analysis of quantum fluctuation in a
vacuum field in the presence of orthogonal linearly polarized pump field
propagating through a Rb vapor cell. Previously reported theoretical and
experimental studies provided somewhat contradictory conclusions regarding the
possibility to observe the "squeezed vacuum" -- the reduction of vacuum
fluctuations below standard quantum limit -- in this system. Here, using the D1
transitions of Rb in a cell without buffer as as an example, we demonstrate
that vacuum squeezing is corrupted by incoherent processes (such as spontaneous
emission, elastic scattering, etc.), and its observation is only possible in a
specific small region of the experimental parameter space. Numerical
simulations, in good agreement with the experiment, demonstrate that the two
excited state hyperfine levels play a crucial role in the squeezing and excess
noise production. The significant influence of far-detuned atoms on the field
fluctuations at low noise frequencies imposes the explicit consideration of the
full velocity distribution of the atomic vapor.


  We consider the low energy phenomenology of superstrings. In particular we
analyse supersymmetry breaking via gaugino condensate and we compare the
phenomenology of the two different approaches to stabilize the dilaton field.
We study the cosmological constant problem and we show that it is possible to
have supersymmetry broken and zero cosmological constant. Finally, we discuss
the possibility of having an inflationary potential. Requiring that the
potential does not destabilize the dilaton field imposes an upper limit to the
density fluctuations which can be consistent with the COBE data.


  In the paper we provide the construction of a coincidence degree being a
homotopy invariant detecting the existence of solutions of equations or
inclusions of the form $Ax\in F(x)$, $x\in U$, where $A\colon D(A)\multimap
  E$ is an $m$-accretive operator in a Banach space $ E$, $F\colon K\multimap
E$ is a weakly upper semicontinuous set-valued map constrained to an open
subset $U$ of a closed set $K\subset E$. Two different approaches will be
presented. The theory is applied to show the existence of nontrivial positive
solutions of some nonlinear second order partial differential equations with
discontinuities.


  We discuss the structure of Deltaron dibaryon in the chiral SU(3) quark
model. The energy of Deltaron is obtained by considering the coupling of the
$\Delta\Delta$ and $CC$ (hidden color) channels. The effects of various
parameters on the Deltaron mass are also studied. It is shown that the mass of
Deltaron is lower than the mass of $\Delta\Delta$ but higher than the mass of
$\Delta N \pi$.


  A general prescription for constructing quasi-local conserved quantities in
General Relativity is proposed. The construction is applied to BMS symmetry
generators in Newman-Unti gauge, so as to define quasi-local BMS charges. It is
argued that the zero mode of this BMS charge is a promising definition of
quasi-local energy.


  We develop methods for estimating the size of hard-to-reach populations from
data collected using network-based questions on standard surveys. Such data
arise by asking respondents how many people they know in a specific group
(e.g., people named Michael, intravenous drug users). The Network Scale up
Method (NSUM) is a tool for producing population size estimates using these
indirect measures of respondents' networks. Killworth et al. [Soc. Netw. 20
(1998a) 23-50, Evaluation Review 22 (1998b) 289-308] proposed maximum
likelihood estimators of population size for a fixed effects model in which
respondents' degrees or personal network sizes are treated as fixed. We extend
this by treating personal network sizes as random effects, yielding principled
statements of uncertainty. This allows us to generalize the model to account
for variation in people's propensity to know people in particular subgroups
(barrier effects), such as their tendency to know people like themselves, as
well as their lack of awareness of or reluctance to acknowledge their contacts'
group memberships (transmission bias). NSUM estimates also suffer from recall
bias, in which respondents tend to underestimate the number of members of
larger groups that they know, and conversely for smaller groups. We propose a
data-driven adjustment method to deal with this. Our methods perform well in
simulation studies, generating improved estimates and calibrated uncertainty
intervals, as well as in back estimates of real sample data. We apply them to
data from a study of HIV/AIDS prevalence in Curitiba, Brazil. Our results show
that when transmission bias is present, external information about its likely
extent can greatly improve the estimates. The methods are implemented in the
NSUM R package.


  To probe the late evolution history of the Universe, we adopt two kinds of
optimal basis systems. One of them is constructed by performing the principle
component analysis (PCA) and the other is build by taking the multidimensional
scaling (MDS) approach. Cosmological observables such as the luminosity
distance can be decomposed into these basis systems. These basis are optimized
for different kinds of cosmological models that based on different physical
assumptions, even for a mixture model of them. Therefore, the so-called feature
space that projected from the basis systems is cosmological model independent,
and it provide a parameterization for studying and reconstructing the Hubble
expansion rate from the supernova luminosity distance and even gamma-ray bursts
(GRBs) data with self-calibration. The circular problem when using GRBs as
cosmological candles is naturally eliminated in this procedure. By using the
Levenberg-Marquardt (LM) technique and the Markov Chain Monte Carlo (MCMC)
method, we perform an observational constraint on this kind of
parameterization. The data we used include the "joint light-curve analysis"
(JLA) data set that consists of $740$ Type Ia supernovae (SNIa) as well as
$109$ long gamma-ray bursts with the well-known Amati relation.


  We investigate a model of stratified economic interactions between agents
when the notion of spatial location is introduced. The agents are placed on a
network with near-neighbor connections. Interactions between neighbors can
occur only if the difference in their wealth is less than a threshold value
that defines the width of the economic classes. By employing concepts from
spatiotemporal dynamical systems, three types of patterns can be identified in
the system as parameters are varied: laminar, intermittent and turbulent
states. The transition from the laminar state to the turbulent state is
characterized by the activity of the system, a quantity that measures the
average exchange of wealth over long times. The degree of inequality in the
wealth distribution for different parameter values is characterized by the Gini
Coefficient. High levels of activity are associated to low values of the Gini
coefficient. It is found that the topological properties of the network have
little effect on the activity of the system, but the Gini coefficient increases
when the clustering coefficient of the network is increased.


  Highly accurate experimental structure factors of silicon are available in
the literature, and these provide the ideal test for any \emph{ab initio}
method for the construction of the all-electron charge density. In a recent
paper [J. R. Trail and D. M. Bird, Phys. Rev. B {\bf 60}, 7863 (1999)] a method
has been developed for obtaining an accurate all-electron charge density from a
first principles pseudopotential calculation by reconstructing the core region
of an atom of choice. Here this method is applied to bulk silicon, and
structure factors are derived and compared with experimental and Full-potential
Linear Augmented Plane Wave results (FLAPW). We also compare with the result of
assuming the core region is spherically symmetric, and with the result of
constructing a charge density from the pseudo-valence density + frozen core
electrons. Neither of these approximations provide accurate charge densities.
The aspherical reconstruction is found to be as accurate as FLAPW results, and
reproduces the residual error between the FLAPW and experimental results.


  A new angular momentum projection for systems of particles with arbitrary
spins is formulated based on the Heine-Stieltjes correspondence, which can be
regarded as the solutions of the mean-field plus pairing model in the strong
pairing interaction G ->Infinity limit. Properties of the Stieltjes zeros of
the extended Heine-Stieltjes polynomials, of which the roots determine the
projected states, and the related Van Vleck zeros are discussed. The
electrostatic interpretation of these zeros is presented. As examples,
applications to n nonidentical particles of spin-1/2 and to identical bosons or
fermions are made to elucidate the procedure and properties of the Stieltjes
zeros and the related Van Vleck zeros. It is shown that the new angular
momentum projection for n identical bosons or fermions can be simplified with
the branching multiplicity formula of U(N) supset O(3) and the special choices
of the parameters used in the projection. Especially, it is shown that the
solutions for identical bosons can always be expressed in terms of zeros of
Jacobi polynomials. However, unlike non-identical particle systems, the
n-coupled states of identical particles are non-orthogonal with respect to the
multiplicity label after the projection.


  We consider the problem of minimizing the entropy of a law with respect to
the law of a reference branching Brownian motion under density constraints at
an initial and final time. We call this problem the branching Schr\"odinger
problem by analogy with the Schr\"odinger problem, where the reference process
is a Brownian motion. Whereas the Schr\"odinger problem is related to
regularized (a.k.a. entropic) optimal transport, we investigate here the link
of the branching Schr\"odinger problem with regularized unbalanced optimal
transport.
  This link is shown at two levels. First, relying on duality arguments, the
values of these two problems of calculus of variations are linked, in the sense
that the value of the regularized unbalanced optimal transport (seen as a
function of the initial and final measure) is the lower semi-continuous
relaxation of the value of the branching Schr\"odinger problem. Second, we also
explicit a correspondence between the competitors of these two problems, and to
that end we provide a fine description of laws having a finite entropy with
respect to a reference branching Brownian motion.
  We investigate the small noise limit, when the noise intensity of the
branching Brownian motion goes to $0$: in this case we show, at the level of
the optimal transport model, that there is convergence to partial optimal
transport. We also provide formal arguments about why looking at the branching
Brownian motion, and not at other measure-valued branching Markov processes,
like superprocesses, yields the problem closest to optimal transport. Finally,
we explain how this problem can be solved numerically: the dynamical
formulation of regularized unbalanced optimal transport can be discretized and
solved via convex optimization.


  For each regular cardinal k > w we show the consistent existence of a thin
very tall superatomic Boolean algebra of width k.


  Classical mechanics is formulated in complex Hilbert space with the
introduction of a commutative product of operators, an antisymmetric bracket,
and a quasidensity operator. These are analogues of the star product, the Moyal
bracket, and the Wigner function in the phase space formulation of quantum
mechanics. Classical mechanics can now be viewed as a deformation of quantum
mechanics. The forms of semiquantum approximations to classical mechanics are
indicated.


  The radio-quiet quasar SDSS J1536+0441A shows two broad-line emission
systems, recently interpreted as a binary black hole (BBH) system with a
subparsec separation; as a double-peaked emitter; or as both types of systems.
The NRAO VLBA was used to search for 8.4 GHz emission from SDSS J1536+0441A,
focusing on the optical localization region for the broad-line emission, of
area 5400 mas^2 (0.15 kpc^2). One source was detected, with a diameter of less
than 1.63 mas (8.5 pc) and a brightness temperature T_b > 1.2 x 10^7 K. New
NRAO VLA photometry at 22.5 GHz, and earlier photometry at 8.5 GHz, gives a
rising spectral slope of alpha = 0.35+/-0.08. The slope implies an optically
thick synchrotron source, with a radius of about 0.04 pc, and thus T_b ~ 5 x
10^10 K. The implied radio-sphere at rest frame 31.2 GHz has a radius of 800
gravitational radii, just below the size of the broad line region in this
object. Observations at higher frequencies can probe whether or not the
radio-sphere is as compact as expected from the coronal framework for the radio
emission of radio-quiet quasars.


  We consider the quantum multisoliton scattering problem. For BPS theories one
truncates the full field theory to the moduli space, a finite dimensional
manifold of energy minimising field configurations, and studies the quantum
mechanical problem on this. Non-BPS theories -- the generic case -- have no
such obvious truncation. We define a quantum soliton scattering manifold as a
configuration space which satisfies asymptotic completeness and respects the
underlying classical dynamics of slow moving solitons. Having done this, we
present a new method to construct such manifolds. In the BPS case the dimension
of the $n$-soliton moduli space $\mathcal{M}_n$ is $n$ multiplied by the
dimension of $\mathcal{M}_1$. We show that this scaling is not necessarily
valid for scattering manifolds in non-BPS theories, and argue that it is false
for the Skyrme and baby-Skyrme models. In these models, we show that a relative
phase difference can generate a relative size difference during a soliton
collision. Asymptotically, these are zero and non-zero modes respectively and
this new mechanism softens the dichotomy between such modes. Using this
discovery, we then show that all previous truncations of the 2-Skyrmion
configuration space are unsuitable for the quantum scattering problem as they
have the wrong dimension. This gives credence to recent numerical work which
suggests that the low-energy configuration space is 14-dimensional (rather than
12-dimensional, as previously thought). We suggest some ways to construct a
suitable manifold for the 2-Skyrmion problem, and discuss applications of our
new definition and construction for general soliton theories.


  We discuss the proper starting point to look into flavor physics under the
perspective of solving the hierarchy problem with the little Higgs mechanism --
the construction of anomaly free fermionic spectra of the effective theory of
extended electroweak gauge symmetry around the TeV scale. Anomaly cancellations
among the three SM families, plus extra fermions, are typically needed, giving
family non-universal flavor structures. Such a completed and consistent
fermionic spectrum supplements a scalar sector little Higgs model, turning the
latter into a realistic model the phenomenological viability of which can then
be investigated. The implications for flavor physics are specially interesting.
We give more elaborated discussion here on our basic perspective, trying to
clarify on issues that are in our opinion under-appreciated. We also add a
brief comment of little Higgs versus supersymmetry.


  Formal verification of neural networks is essential before their deployment
in safety-critical applications. However, existing methods for formally
verifying neural networks are not yet scalable enough to handle practical
problems involving a large number of neurons. We address this challenge by
introducing a fully automatic and sound reduction of neural networks using
reachability analysis. The soundness ensures that the verification of the
reduced network entails the verification of the original network. To the best
of our knowledge, we present the first sound reduction approach that is
applicable to neural networks with any type of element-wise activation
function, such as ReLU, sigmoid, and tanh. The network reduction is computed on
the fly while simultaneously verifying the original network and its
specifications. All parameters are automatically tuned to minimize the network
size without compromising verifiability. We further show the applicability of
our approach to convolutional neural networks by explicitly exploiting similar
neighboring pixels. Our evaluation shows that our approach can reduce the
number of neurons to a fraction of the original number of neurons with minor
outer-approximation and thus reduce the verification time to a similar degree.


  According to the helicity conservation (HCns) theorem, the sum of the
helicities should be conserved, in any 2-to-2 processes in MSSM with R-parity
conservation, at high energies; i.e. all amplitudes violating this rule, must
vanish asymptotically. The realization of HCns in gluon-fusion to charginos or
neutralinos is studied, at the one loop electroweak order (EW), and simple high
energy expressions are derived for the non-vanishing helicity conserving (HC)
amplitudes. These are very similar to the corresponding expressions for $gg \to
W^+W^-, ZZ, \gamma Z, \gamma\gamma $ derived before. Asymptotic relations among
observable unpolarized cross sections for many such processes are then
obtained, some of which may hold at LHC-type energies.


  Some remarks are made about free anomaly groups in gauged WZW models.
Considering a quite general action, anomaly cancellation is analyzed. The
possibility of gauging left and right sectors independently in some cases is
remarked. In particular Toda theories can be seen as such a kind of models.


  We derive an analytical description of neutrino oscillations in matter based
on the Magnus exponential representation of the time evolution operator. Our
approach is valid in a wide range of the neutrino energies and properly
accounts for the modifications that the respective probability transitions
suffer when neutrinos originated in different sources traverse the Earth. The
present approximation considerably improves over other perturbative treatments
existing in the current literature. Furthermore, the analytical expressions
derived inside the Magnus framework are remarkably simple, which facilitates
their practical use. When applied to the calculation of the day-night asymmetry
in the solar neutrino flux our result reproduces the numerical calculation with
an accuracy better than 1% for the first order approximation. When the
approximation is extended to the second order, the accuracy of the method is
further improved by almost one order of magnitude, and it is still better than
5% even for neutrino energies as large as 100 MeV. In the GeV regime
characteristic of atmospheric and accelerator neutrinos this accuracy is
complemented by a good reproduction of the position of the maxima in the flavor
transition probabilities.


  We study the 2d N = 4 gauge theory descriptions of little strings on type II
NS5- branes. The IIB strings on N NS5-branes are described by the N = (4,4)
gauge theories, whose Higgs branch CFTs on U(N) instanton moduli spaces are
relevant. The IIA strings are described by N = (4,4) circular A_{N-1} quiver
theories, whose Coulomb branch CFTs are relevant. We study new N = (0,4) quiver
gauge theories for the IIA strings, which make it easier to study some infrared
observables. In particular, we show that the elliptic genera of the IIA / IIB
strings precisely map to each other by T-duality.


  Cloud platforms today have been deploying hardware accelerators like neural
processing units (NPUs) for powering machine learning (ML) inference services.
To maximize the resource utilization while ensuring reasonable quality of
service, a natural approach is to virtualize NPUs for efficient resource
sharing for multi-tenant ML services. However, virtualizing NPUs for modern
cloud platforms is not easy. This is not only due to the lack of system
abstraction support for NPU hardware, but also due to the lack of architectural
and ISA support for enabling fine-grained dynamic operator scheduling for
virtualized NPUs.
  We present TCloud, a holistic NPU virtualization framework. We investigate
virtualization techniques for NPUs across the entire software and hardware
stack. TCloud consists of (1) a flexible NPU abstraction called vNPU, which
enables fine-grained virtualization of the heterogeneous compute units in a
physical NPU (pNPU); (2) a vNPU resource allocator that enables pay-as-you-go
computing model and flexible vNPU-to-pNPU mappings for improved resource
utilization and cost-effectiveness; (3) an ISA extension of modern NPU
architecture for facilitating fine-grained tensor operator scheduling for
multiple vNPUs. We implement TCloud based on a production-level NPU simulator.
Our experiments show that TCloud improves the throughput of ML inference
services by up to 1.4$\times$ and reduces the tail latency by up to
4.6$\times$, while improving the NPU utilization by 1.2$\times$ on average,
compared to state-of-the-art NPU sharing approaches.


  We bound the performance guarantees that follow from Tur\'an-like bounds for
unweighted and weighted independent sets in bounded-degree graphs. In
particular, a randomized approach of Boppana forms a simple 1-round distributed
algorithm, as well as a streaming and preemptive online algorithm. We show it
gives a tight $(\Delta+1)/2$-approximation in unweighted graphs of maximum
degree $\Delta$, which is best possible for 1-round distributed algorithms. For
weighted graphs, it gives only a $\Delta$-approximation, but a simple
modification results in an asymptotic expected $0.529 \Delta$-approximation.
This compares with a recent, more complex $\Delta$-approximation~\cite{BCGS17},
which holds deterministically.


  2d hydrodynamical simulations are performed to examine the evaporation and
condensation processes of giant molecular clouds in the hot phase of the
interstellar medium. The evolution of cold and dense clouds is calculated in
the subsonic stream of a hot tenuous plasma. Our code includes self-gravity,
heating and cooling processes and heat conduction by electrons. Significant
differences occur between simulations with and without heat conduction.


  In this study, effects of the shell material and confinement type on the
conversion efficiency of the core/shell quantum dot nanocrystal (QDNC) solar
cells have been investigated in a detail manner. For this purpose, the
conventional, i.e original, detailed balance model, developed by Shockley and
Queisser to calculate an upper limit for conversion efficiency of silicon p-n
junction solar cells, is modified in a simple and an effective way and
calculated the conversion efficiency of core/shell QDNC solar cells. Since the
existing model relies on the gap energy ($E_g$) of the solar cell, it does not
make an estimation about the effect of QDNC materials on the efficiency of the
solar cells and gives the same efficiency values for several QDNC solar cells
with the same $E_g$. The proposed modification, however, estimates a conversion
efficiency in relation to the material properties and also confinement type of
the QDNCs. The results of the modified model show that, in contrast to the
original one, the conversion efficiencies of different QDNC solar cells, even
if they have the same $E_g$, become different depending upon the confinement
type and shell material of the core/shell QDNCs and this is crucial in design
and fabrication of the new generation solar cells to predict the confinement
type and also appropriate QDNC materials for better efficiency.


  This paper concerns a second-order differential equation with indefinite and
repulsive singularities. It is the first time to study differential equation
containing both indefinite and repulsive singularities simultaneously. A set of
sufficient conditions are obtained for the existence of positive periodic
solutions. The theoretical underpinnings of this paper are the positivity of
Green's function and fixed point theorem in cones. Our results improve and
extend the results in previous literatures. Finally, three examples and their
numerical simulations (phase diagrams and time diagrams of periodic solutions)
are given to show the effectiveness of our conclusions.


  In this paper, we consider a reconfigurable intelligent surface (RIS) and
model it by using multiport network theory. We first compare the representation
of RIS by using $Z$-parameters and $S$-parameters, by proving their equivalence
and discussing their distinct features. Then, we develop an algorithm for
optimizing the RIS configuration in the presence of electromagnetic mutual
coupling. We show that the proposed algorithm based on optimizing the
$S$-parameters results in better performance than existing algorithms based on
optimizing the $Z$-parameters. This is attributed to the fact that small
perturbations of the step size of the proposed algorithm result in larger
variations of the $S$-parameters, hence increasing the convergence speed of the
algorithm.


  Quasi-periodic X-ray eruptions (QPEs) are a recently discovered phenomenon,
the nature of which remains unclear. Based on their discovery in active
galactic nuclei (AGN), explanations related to an AGN accretion disk, or
potentially stellar tidal disruption event (TDE), were put forward. Following
the report of QPEs in apparently passive galaxies, alternatives including
highly unequal mass compact object binaries have been proposed to explain their
properties. We perform a systematic study of the five known QPE host galaxies
with the aim of providing new insights into their nature. We analyse new and
archival medium resolution optical spectroscopy of the QPE hosts. We measure
emission (and absorption) line fluxes, their ratios and equivalent widths
(EWs), to locate the QPE hosts on diagnostic diagrams. We also measure the
velocity dispersion of the stellar absorption lines to estimate their black
hole masses. All QPE host galaxies show emission lines in their optical
spectra. Based on their ratios and EWs, we find evidence for the presence of an
active galactic nucleus in all sources, including those previously reported as
passive. We measure velocity dispersions between 36 and 90 km/s, implying the
presence of low mass (10^5-6.7 solar masses) black holes, consistent with
literature findings. Finally, we find a significant over-representation (2/5
sources, or a factor of 13 +13 -10.5) of quiescent, Balmer strong (post
starburst) galaxies among QPE hosts. The presence of a narrow line region
consistent with an AGN in all QPE host galaxies implies that a pre-existing
accretion flow likely plays an integral part to the QPE phenomenon. The strong
over-representation of quiescent Balmer strong galaxies among QPE hosts can be
naturally explained in both the TDE and interacting extreme mass ratio inspiral
hypotheses.


  We provide the first estimate of the number of fine, regular, star
triangulations of the four-dimensional reflexive polytopes, as classified by
Kreuzer and Skarke (KS). This provides an upper bound on the number of
Calabi-Yau threefold hypersurfaces in toric varieties. The estimate is
performed with deep learning, specifically the novel equation learner (EQL)
architecture. We demonstrate that EQL networks accurately predict numbers of
triangulations far beyond the $h^{1,1}$ training region, allowing for reliable
extrapolation. We estimate that number of triangulations in the KS dataset is
$10^{10,505}$, dominated by the polytope with the highest $h^{1,1}$ value.


  Cooper pairing is studied in three dimensions to determine its binding energy
for all coupling using a general separable interfermion interaction. Also
considered are Cooper pairs (CPs) with nonzero center-of-mass momentum (CMM). A
coupling-independent {\it linear} term in the CMM dominates the pair excitation
energy in weak coupling and/or high fermion density, while the more familiar
quadratic term prevails only in the extreme low-density (i.e., vacuum) limit
for any nonzero coupling. The linear-to-quadratic crossover of the CP
dispersion relation is analyzed numerically, and is expected to play a central
role in a model of superconductivity (and superfluidity) simultaneously
accommodating a BCS condensate as well as a Bose-Einstein condensate of CP
bosons.


  We define a new class of racks, called finitely stable racks, which, to some
extent, share various flavors with Abelian groups. Characterization of finitely
stable Alexander quandles is established. Further, we study twisted rack
dynamical systems, construct their cross-products, and introduce representation
theory of racks and quandles. We prove several results on the {\em strong}
representations of finite connected involutive racks analogous to the
properties of finite Abelian groups. Finally, we define the {\em Pontryagin}
dual of a rack as an Abelian group which, in the finite involutive connected
case, coincides with the set of its strong irreducible representations.


  Motivated by the recent works of Refs. \cite{R1, R2} where a model of
inflation has been suggested with non-minimally coupled massive vector fields,
we generalize their work to the study of the bouncing solution. So we consider
a massive vector field, which is non-minimally coupled to gravity. Also we
consider non-minimal coupling of vector field to the scalar curvature. Then we
reconstruct this model in the light of three forms of parametrization for
dynamical dark energy. Finally we simply plot reconstructed physical quantities
in flat universe.


  We reconsider the idea of identifying the Higgs field as the internal
component of a gauge field in the flat space R^4XS^1/Z_2, by relaxing the
constraint of having unbroken SO(4,1) Lorentz symmetry in the bulk. In this
way, we show that the main common problems of previous models of this sort,
namely the prediction of a too light Higgs and top mass, as well as of a too
low compactification scale, are all solved. We mainly focus our attention on a
previously constructed model. We show how, with few minor modifications and by
relaxing the requirement of SO(4,1) symmetry, a potentially realistic model can
be obtained with a moderate tuning in the parameter space of the theory. In
this model, the Higgs potential is stabilized and the hierarchy of fermion
masses explained.


  The phenomenon of stable persistent currents is central to the studies of
superfluidity in a range of physical systems. While all of the previous
theoretical studies of superfluid flows in annular geometries concentrated on
conservative systems, here we extend the stability analysis of persistent
currents to open-dissipative exciton-polariton superfluids. By considering an
exciton-polariton condensate in an optically-induced annular trap, we determine
stability conditions for an initially imposed flow with a non-zero orbital
angular momentum. We show, theoretically and numerically, that the system can
sustain metastable persistent currents in a large parameter region, and
describe scenarios of the supercurrent decay due to the dynamical instability.


  A compressed sensing scheme for near-field imaging of corrugations of
relative sparse Fourier components is proposed. The scheme employs random
sparse measurement of near field to recover the angular spectrum of the
scattered field. It is shown heuristically and numerically that under the
Rayleigh hypothesis the angular spectrum is compressible and amenable to
compressed sensing techniques.
  Iteration schemes are developed for recovering the surface profile from the
angular spectrum.
  The proposed nonlinear least squares in the Fourier basis produces accurate
reconstructions even when the Rayleigh hypothesis is known to be false.


  Meta-heuristics are powerful tools for solving optimization problems whose
structural properties are unknown or cannot be exploited algorithmically. We
propose such a meta-heuristic for a large class of optimization problems over
discrete domains based on the particle swarm optimization (PSO) paradigm. We
provide a comprehensive formal analysis of the performance of this algorithm on
certain "easy" reference problems in a black-box setting, namely the sorting
problem and the problem OneMax. In our analysis we use a Markov model of the
proposed algorithm to obtain upper and lower bounds on its expected
optimization time. Our bounds are essentially tight with respect to the Markov
model. We show that for a suitable choice of algorithm parameters the expected
optimization time is comparable to that of known algorithms and, furthermore,
for other parameter regimes, the algorithm behaves less greedy and more
explorative, which can be desirable in practice in order to escape local
optima. Our analysis provides a precise insight on the tradeoff between
optimization time and exploration. To obtain our results we introduce the
notion of indistinguishability of states of a Markov chain and provide bounds
on the solution of a recurrence equation with non-constant coefficients by
integration.


  $\eta$ Carinae is a colliding wind binary hosting two of the most massive
stars and featuring the strongest wind collision mechanical luminosity. The
wind collision region of this system is detected in X-rays and $\gamma$-rays
and offers a unique laboratory for the study of particle acceleration and wind
magneto-hydrodynamics. Our main goal is to use X-ray observations of $\eta$
Carinae around periastron to constrain the wind collision zone geometry and
understand the reasons for its variability. We analysed 10 Nuclear
Spectroscopic Telescope Array (NuSTAR) observations, which were obtained around
the 2014 periastron. The NuSTAR array monitored the source from 3 to 30 keV,
which allowed us to grasp the continuum and absorption parameters with very
good accuracy. We were able to identify several physical components and probe
their variability. The X-ray flux varied in a similar way as observed during
previous periastrons and largely as expected if generated in the wind collision
region. The flux detected within ~10 days of periastron is lower than expected,
suggesting a partial disruption of the central region of the wind collision
zone. The Fe K$\alpha$ line is likely broadened by the electrons heated along
the complex shock fronts. The variability of its equivalent width indicates
that the fluorescence region has a complex geometry and that the source
obscuration varies quickly with the line of sight.


  Typically, every part in most coherent text has some plausible reason for its
presence, some function that it performs to the overall semantics of the text.
Rhetorical relations, e.g. contrast, cause, explanation, describe how the parts
of a text are linked to each other. Knowledge about this socalled discourse
structure has been applied successfully to several natural language processing
tasks. This work studies the use of rhetorical relations for Information
Retrieval (IR): Is there a correlation between certain rhetorical relations and
retrieval performance? Can knowledge about a document's rhetorical relations be
useful to IR? We present a language model modification that considers
rhetorical relations when estimating the relevance of a document to a query.
Empirical evaluation of different versions of our model on TREC settings shows
that certain rhetorical relations can benefit retrieval effectiveness notably
(> 10% in mean average precision over a state-of-the-art baseline).


  It is known that any two-outcome quantum measurement can be decomposed into a
continuous stochastic process using a feedback loop. In this article, we
characterize which of these decompositions are possible when each iteration of
the feedback loop consists of a weak measurement caused by an interaction with
a probe system. We restrict ourselves to the case when the probe is a qubit and
the interaction Hamiltonian between the probe and system is constant. We find
that even given the ability to perform arbitrary unitary pulses throughout the
continuous decomposition, only generalized measurements with two distinct
singular values are achievable. However, this is sufficient to decompose a
generalized qubit measurement using a qubit probe and a simple interaction
Hamiltonian.


  We utilize the coset construction to derive the effective field theory of
magnon-phonon interactions in (anti)-ferromagnetic and ferrimagnetic insulating
materials. The action is used to calculate the equations of motion which
generalize the Landau-Lifshitz and stress equations to allow for
magneto-acoustic couplings to all orders in the fields at lowest order in the
derivative expansion. We also include the symmetry breaking effects due to
Zeeman, and Dzyaloshinsky-Moriya interactions. This effective theory is a
toolbox for the study of magneto-elastic phenomena from first principles. As an
example we use this theory to calculate the leading order contribution to the
magnon decay width due to its the decay into phonons.


  The curvature estimates of $k$ curvature equations for general right hand
side is a longstanding problem. In this paper, we totally solve the $n-1$ case
and we also discuss some applications for our estimate.


  Electric vehicle (EV) is a significant type of distributed energy resources
(DERs), that provide flexibilities to grid operators to achieve a myriad of
objectives. This paper presents a comprehensive modeling framework of EVs under
multiple real-world demand response (DR) markets in California and provides
combined strategies to maximize the revenues via unidirectional EV-Grid
integrations (V1G). EV itinerary and usage information from a commercial
demonstration site is utilized to model the EV flexibilities, based on which,
we modeled the heterogeneous market rules using mixed-integer programming
approaches. The system cost-saving performance is analyzed with respect to
fleet properties and market constraints, including flexibility, participation
threshold, and baseline calculaton, etc.


  A discrete subgroup $\Gamma$ of a locally compact group $H$ is called a
uniform lattice if the quotient $H/\Gamma$ is compact. Such an $H$ is called an
envelope of $\Gamma$. In this paper we study the problem of classifying
envelopes of various solvable groups including the solvable Baumslag-Solitar
groups, lamplighter groups and certain abelian-by-cyclic groups. Our techniques
are geometric and quasi-isometric in nature. In particular we show that for
every $\Gamma$ we consider there is a finite family of preferred model spaces
$X$ such that, up to compact groups, $H$ is a cocompact subgroup of $Isom(X)$.


  Nanoplasmonic systems combined with optically-active two-dimensional
materials provide intriguing opportunities to explore and control light-matter
interactions at extreme sub-wavelength lengthscales approaching the exciton
Bohr radius. Here, we present room- and cryogenic-temperature investigations of
light-matter interactions between an MoSe$_2$ monolayer and individual
lithographically defined gold dipole nanoantennas having sub-10 nm feed gaps.
By progressively tuning the nanoantenna size, their dipolar resonance is tuned
relative to the A-exciton transition in a proximal MoSe$_2$ monolayer achieving
a total tuning of $\sim 130\;\mathrm{meV}$. Differential reflectance
measurements performed on $> 100$ structures reveal an apparent avoided
crossing between exciton and dipolar mode and an exciton-plasmon coupling
constant of $g= 55\;\mathrm{meV}$, representing $g/(\hbar\omega_X)\geq3\%$ of
the transition energy. This places our hybrid system in the
intermediate-coupling regime where spectra exhibit a characteristic Fano-like
shape, indicative of the interplay between pronounced light-matter coupling and
significant damping. We also demonstrate active control of the optical response
by varying the polarization of the excitation light to programmably suppress
coupling to the dipole mode. We further study the emerging optical signatures
of the monolayer localized at dipole nanoantennas at $10\;\mathrm{K}$. Our
findings represent a key step towards realizing non-linear photonic devices
based on 2D materials with potential for low-energy and ultrafast performance.


  We study the generation of non-equilibrium spin currents in systems with
spatially-inhomogeneous magnetic potentials. For sufficiently high current
densities, the spin polarization can be transported over distances
significantly exceeding the intrinsic spin-diffusion length. This enables
applications that are impossible within the conventional spin-diffusion regime.
Specifically, we propose dc measurement schemes for the carrier spin relaxation
times, $T_1$ and $T_2$, as well as demonstrate the possibility of spin species
separation by driving current through a region with an inhomogeneous magnetic
potential.


  We study the sample complexity of semi-supervised learning (SSL) and
introduce new assumptions based on the mismatch between a mixture model learned
from unlabeled data and the true mixture model induced by the (unknown) class
conditional distributions. Under these assumptions, we establish an
$\Omega(K\log K)$ labeled sample complexity bound without imposing parametric
assumptions, where $K$ is the number of classes. Our results suggest that even
in nonparametric settings it is possible to learn a near-optimal classifier
using only a few labeled samples. Unlike previous theoretical work which
focuses on binary classification, we consider general multiclass classification
($K>2$), which requires solving a difficult permutation learning problem. This
permutation defines a classifier whose classification error is controlled by
the Wasserstein distance between mixing measures, and we provide finite-sample
results characterizing the behaviour of the excess risk of this classifier.
Finally, we describe three algorithms for computing these estimators based on a
connection to bipartite graph matching, and perform experiments to illustrate
the superiority of the MLE over the majority vote estimator.


  The non-abelian self-dual action in three dimensions is derived using the
self-interaction mechanism.


  In a recent paper [J. Opt. B: Quantum Semiclass. Opt. 5 (2003) 155-157], a
quantum key distribution scheme based on entanglement swapping was proposed,
which exhibited two improvements over the previous protocols. In this Comment,
it is shown that the scheme has no properties as been discussed.


  Elastic scattering of pions from finite nuclei is investigated utilizing a
contemporary, momentum--space first--order optical potential combined with
microscopic estimates of second--order corrections. The calculation of the
first--order potential includes:\ \ (1)~full Fermi--averaging integration
including both the delta propagation and the intrinsic nonlocalities in the
$\pi$-$N$ amplitude, (2)~fully covariant kinematics, (3)~use of invariant
amplitudes which do not contain kinematic singularities, and (4)~a
finite--range off--shell pion--nucleon model which contains the nucleon pole
term. The effect of the delta--nucleus interaction is included via the mean
spectral--energy approximation. It is demonstrated that this produces a
convergent perturbation theory in which the Pauli corrections (here treated as
a second--order term) cancel remarkably against the pion true absorption terms.
Parameter--free results, including the delta--nucleus shell--model potential,
Pauli corrections, pion true absorption, and short--range correlations are
presented. (2 figures available from authors)


  We have studied the null-plane hamiltonian structure of the free Yang-Mills
fields and the scalar chromodynamics ($SQCD_{4}$). Following the Dirac's
procedure for constrained systems we have performed a detailed analysis of the
constraint structure of both models and we give the generalized Dirac brackets
for the physical variables. In the free Yang-Mills case, using the
correspondence principle in the Dirac's brackets we obtain the same commutators
present in the literature.


  In this paper we define a regularized version of the analytic torsion for
quotients of a symmetric space of non-positive curvature by arithmetic
lattices. The definition is based on the study of the renormalized trace of the
corresponding heat operators, which is defined as the geometric side of the
Arthur trace formula applied to the heat kernel. Then we study the limiting
behavior of the analytic torsion as the lattices run through a sequence of
congruence subgroups of a fixed arithmetic subgroup. Our main result states
that for sequences of principal congruence subgroups, which converge to 1 at a
fixed finite set of places and strongly acyclic flat bundles, the logarithm of
the analytic torsion, divided by the index of the subgroup, converges to the
$L^2$-analytic torsion.


  We present an innovative approach to dimensional analysis, based on a general
representation theorem for complete quantity functions admitting a covariant
scalar representation; this theorem is in turn grounded in a purely algebraic
theory of quantity spaces. Examples of dimensional analysis based on this
approach are given, showing that it allows results obtained by traditional
dimensional analysis to be strengthened. For example, the orbital period of a
two-body system can be derived without use of equations of motion.


  We point out that if quark and lepton masses arise dynamically, then in a
wide class of theories the corresponding running masses $m_{f_j}(p)$ exhibit
the power-law decay $m_{f_j}(p) \propto \Lambda_j^2/p^2$ for Euclidean momenta
$p >> \Lambda_j$, where $f_j$ is a fermion of generation $j$, and $\Lambda_j$
is the maximal scale relevant for the origin of $m_{f_j}$. We estimate
resultant changes in precision electroweak quantities and compare with current
data. It is found that this data allows the presence of such corrections. We
also note that this power-law decay renders primitively divergent fermion mass
corrections finite.


  We prove that a $BV$ map with values into the projective space
$\mathbb{RP}^{d-1}$ has a $BV$ lifting with values into the unit sphere
$\mathbb S^{d-1}$ that satisfies an optimal $BV$-estimate. As an application to
liquid crystals, this result is also stated for $BV$ maps with values into the
set of uniaxial $Q$-tensors. In order to quantify $BV$ liftings, we prove an
explicit formula for an intrinsic $BV$-energy of maps with values into any
compact smooth manifold.


  Modeling the distribution of natural images is a landmark problem in
unsupervised learning. This task requires an image model that is at once
expressive, tractable and scalable. We present a deep neural network that
sequentially predicts the pixels in an image along the two spatial dimensions.
Our method models the discrete probability of the raw pixel values and encodes
the complete set of dependencies in the image. Architectural novelties include
fast two-dimensional recurrent layers and an effective use of residual
connections in deep recurrent networks. We achieve log-likelihood scores on
natural images that are considerably better than the previous state of the art.
Our main results also provide benchmarks on the diverse ImageNet dataset.
Samples generated from the model appear crisp, varied and globally coherent.


  We construct the moduli space of cubic surfaces which do not admit a
Sylvester form as an arithmetic quotient, and determine the graded ring of
modular forms of even weights.


  The discovery of the topological states has become a key topic in condensed
matter physics with the focus evolving from the Dirac or Weyl points to
high-dimension topological states of the nodal lines and nodal surfaces. For a
topological material to manifest its quantum properties and become useful in
applications, the topological states need to be genuine and clean so that they
lie close to the Fermi level without other trivial bands existing at the Fermi
level. While a number of high-dimension topological materials are predicted,
only a few of them have been synthesized and confirmed and the genuine and
clean ones are especially scarce. Here we report the realization of the genuine
clean multiple high-dimension topological states in NaAlSi. By performing
high-resolution angle-resolved photoemission measurements and band structure
calculations, we have observed two sets of nodal surfaces and the formation of
two homocentric nodal ring states in NaAlSi. The observed nodal rings are
distinct in that the inner one is a
type-{\uppercase\expandafter{\romannumeral1}} nodal ring while the outer one is
a type-{\uppercase\expandafter{\romannumeral1}} nodal ring embedded with four
type-{\uppercase\expandafter{\romannumeral3}} nodal points. All the bands
involved in the nodal rings lie very close to the Fermi level with no other
trivial bands coexisting at the Fermi level. These observations make NaAlSi a
desirable topological material to explore for novel quantum states and exotic
properties.


  We summarize the current status of our understanding of nuclear forces based
upon chiral symmetry--an idea that was advocated by Gerry Brown already several
decades ago.


  A dramatic increase in the number of outbreaks of Dengue has recently been
reported, and climate change is likely to extend the geographical spread of the
disease. In this context, this paper shows how a neural network approach can
incorporate Dengue and COVID-19 data as well as external factors (such as
social behaviour or climate variables), to develop predictive models that could
improve our knowledge and provide useful tools for health policy makers.
Through the use of neural networks with different social and natural
parameters, in this paper we define a Correlation Model through which we show
that the number of cases of COVID-19 and Dengue have very similar trends. We
then illustrate the relevance of our model by extending it to a Long short-term
memory model (LSTM) that incorporates both diseases, and using this to estimate
Dengue infections via COVID-19 data in countries that lack sufficient Dengue
data.


  Across many real-time video applications, we see a growing need (especially
in long delays and dynamic bandwidth) to allow clients to decode each frame
once any (non-empty) subset of its packets is received and improve quality with
each new packet. We call it data-scalable delivery. Unfortunately, existing
techniques (e.g., FEC, RS and Fountain Codes) fall short: they require either
delivery of a minimum number of packets to decode frames, and/or pad video data
with redundancy in anticipation of packet losses, which hurts video quality if
no packets get lost. This work explores a new approach, inspired by recent
advances of neural-network autoencoders, which make data-scalable delivery
possible. We present Grace, a concrete data-scalable real-time video system.
With the same video encoding, Grace's quality is slightly lower than
traditional codec without redundancy when no packet is lost, but with each
missed packet, its quality degrades much more gracefully than existing
solutions, allowing clients to flexibly trade between frame delay and video
quality. Grace makes two contributions: (1) it trains new custom autoencoders
to balance compression efficiency and resilience against a wide range of packet
losses; and (2) it uses a new transmission scheme to deliver autoencoder-coded
frames as individually decodable packets. We test Grace (and traditional
loss-resilient schemes and codecs) on real network traces and videos, and show
that while Grace's compression efficiency is slightly worse than heavily
engineered video codecs, it significantly reduces tail video frame delay (by
2$\times$ at the 95th percentile) with the marginally lowered video quality