  When does Internet traffic cross international borders? This question has
major geopolitical, legal and social implications and is surprisingly difficult
to answer. A critical stumbling block is a dearth of tools that accurately map
routers traversed by Internet traffic to the countries in which they are
located. This paper presents Passport: a new approach for efficient, accurate
country-level router geolocation and a system that implements it. Passport
provides location predictions with limited active measurements, using machine
learning to combine information from IP geolocation databases, router
hostnames, whois records, and ping measurements. We show that Passport
substantially outperforms existing techniques, and identify cases where paths
traverse countries with implications for security, privacy, and performance.


  Concepts of everyday use like energy, heat, and temperature have acquired a
precise meaning after the development of thermodynamics. Thermodynamics
provides the basis for understanding how heat and work are related and with the
general rules that the macroscopic properties of systems at equilibrium follow.
Outside equilibrium and away from macroscopic regimes most of those rules
cannot be applied directly. Here we present recent developments that extend the
applicability of thermodynamic concepts deep into mesoscopic and irreversible
regimes. We show how the probabilistic interpretation of thermodynamics
together with probability conservation laws can be used to obtain Fokker-Planck
equations for the relevant degrees of freedom. This approach provides a
systematic method to obtain the stochastic dynamics of a system directly from
its equilibrium properties. A wide variety of situations can be studied in this
way, including many that were thought to be out of reach of thermodynamic
theories, such as non-linear transport in the presence of potential barriers,
activated processes, slow relaxation phenomena, and basic processes in
biomolecules, like translocation and stretching.


  Rare-earth-barium-copper-oxide (REBCO) tapes are now available from several
industrial manufacturers and are very promising conductors in high field
applications. Due to diverging materials and deposition processes, these
manufacturers' tapes can be expected to differ in their electro-mechanical and
mechanical properties. For magnets designers, these are together with the
conductors' in-field critical current performance of the highest importance in
choosing a suitable conductor. In this work, the strain and stress dependence
of the current carrying capabilities as well as the stress and strain
correlation are investigated for commercial coated conductors from Bruker HTS,
Fujikura, SuNAM, SuperOx and SuperPower at 77 K, self-field and 4.2 K, 19 T.


  We prove that the extension of the double ramification cycle defined by the
first-named author (using modifications of the stack of stable curves)
coincides with that defined by the last-two named authors (using an extended
Brill-Noether locus on suitable compactified universal Jacobians). In
particular, in the untwisted case we deduce that both of these extensions
coincide with that constructed by Li and Graber-Vakil using a virtual
fundamental class on a space of rubber maps.


  Let $G$ be a finite group and let $\psi(G)$ denote the sum of element orders
of $G$. It is well-known that the maximum value of $\varphi$ on the set of
groups of order $n$, where $n$ is a positive integer, will occur at the cyclic
group $C_n$. For nilpotent groups, we prove a natural generalization of this
result, obtained by replacing the element orders of $G$ with the element orders
relative to a certain subgroup $H$ of $G$.


  Purpose: The Hard X-ray Modulation Telescope is China's first X-ray astronomy
satellite launched on June 15th, 2017, dubbed Insight-HXMT. Active and passive
thermal control measures are employed to keep devices at suitable temperatures.
In this paper, we analyzed the on-orbit thermal monitoring data of the first 5
years and investigated the effect of thermal deformation on the point spread
function (PSF) of the telescopes.
  Methods: We examined the data of the on-orbit temperatures measured using 157
thermistors placed on the collimators, detectors and their support structures
and compared the results with the thermal control requirements. The thermal
deformation was evaluated by the relative orientation of the two star sensors
installed on the main support structure. its effect was estimated with
evolution of the PSF obtained with calibration scanning observations of the
Crab nebula.
  Conclusion: The on-orbit temperatures met the thermal control requirements
thus far, and the effect of thermal deformation on the PSF was negligible after
the on-orbit pointing calibration.


  Influencing (and being influenced by) others through social networks is
fundamental to all human societies. Whether this happens through the diffusion
of rumors, opinions, or viruses, identifying the diffusion source (i.e., the
person that initiated it) is a problem that has attracted much research
interest. Nevertheless, existing literature has ignored the possibility that
the source might strategically modify the network structure (by rewiring links
or introducing fake nodes) to escape detection. Here, without restricting our
analysis to any particular diffusion scenario, we close this gap by evaluating
two mechanisms that hide the source-one stemming from the source's actions, the
other from the network structure itself. This reveals that sources can easily
escape detection, and that removing links is far more effective than
introducing fake nodes. Thus, efforts should focus on exposing concealed ties
rather than planted entities; such exposure would drastically improve our
chances of detecting the diffusion source.


  Many dynamic processes, including common scenarios in robotic control and
reinforcement learning (RL), involve a set of interacting subprocesses. Though
the subprocesses are not independent, their interactions are often sparse, and
the dynamics at any given time step can often be decomposed into locally
independent causal mechanisms. Such local causal structures can be leveraged to
improve the sample efficiency of sequence prediction and off-policy
reinforcement learning. We formalize this by introducing local causal models
(LCMs), which are induced from a global causal model by conditioning on a
subset of the state space. We propose an approach to inferring these structures
given an object-oriented state representation, as well as a novel algorithm for
Counterfactual Data Augmentation (CoDA). CoDA uses local structures and an
experience replay to generate counterfactual experiences that are causally
valid in the global model. We find that CoDA significantly improves the
performance of RL agents in locally factored tasks, including the
batch-constrained and goal-conditioned settings.


  A classical model for the lattice distortions of $\lax$ is derived and, in a
mean field approximation, solved. The model is based on previous work by
Kanamori and involves localized Mn d-electrons (which induce tetragonal
distortions of the oxygen octahedra surrounding the Mn) and localized holes
(which induce breathing distortions). Parameters are determined by fitting to
the room temperature structure of $LaMnO_3$. The energy gained by formation of
a local lattice distortion is found to be large, most likely $\approx 0.6$ eV
per site, implying a strong electorn-phonon coupling and supporting polaronic
models of transport in the doped materials. The structural transition is shown
to be of the order-disorder type; the rapid x-dependence of the transition
temperature is argued to occur because added holes produce a "random" field
which misaligns the nearby sites.


  We consider the Gaussian free field on the torus whose covariance kernel is
given by the zero-average Green's function. We show that for dimension $d\ge
3$, the extremal point process associated with this field converges weakly to a
Poisson random measure. As an immediate corollary, the maxima of the field
converges after appropriate centering and scaling to the Gumbel distribution.


  In June 2004 QCD was simulated for the first time at sustained speed
exceeding 1 TeraFlops in the BlueGene/L supercomputer at the IBM T.J. Watson
Research Lab. The implementation and performance of QCD in the BlueGene/L is
presented.


  To successfully launch automated vehicles into the consumer market, there
must be credible proof that the vehicles will operate safely. However, finding
a method to validate the vehicles' safe operation is a challenging problem.
While scenario-based test approaches seem to be possible solutions, they
require execution of a large number of test cases. Several test benches,
ranging from actual test vehicles to partly or fully simulated environments,
are available to execute these test cases. Each test bench provides different
elements, which in turn, have different parameters and parameter ranges. The
composition of elements with their specific parameter values at a specific test
bench that is used to execute a test case is referred to as a test bench
configuration. However, selecting the most suitable test bench configuration is
difficult. The selected test bench configuration determines whether the
execution of a specific test case provides sufficiently valid test case results
with respect to the intended purpose, for example, validating a vehicle's safe
operation. The effective and efficient execution of a large number of test
cases requires a method for systematically assigning test cases to the most
suitable test bench configuration. Based on a proposed method for classifying
test bench configurations, we propose and illustrate a method for
systematically assigning test cases to test bench configurations in a
scenario-based test approach for automated vehicles. This assignment method
allows for the effective and efficient execution of a large number of test
cases while generating sufficiently valid test case results.


  We present a framework for the construction of portal effective theories
(PETs) that couple effective field theories of the Standard Model (SM) to light
hidden messenger fields. Using this framework we construct electroweak and
strong scale PETs that couple the SM to messengers carrying spin zero, one
half, or one. The electroweak scale PETs encompass all portal operators up to
dimension five, while the strong scale PETs additionally contain all portal
operators of dimension six and seven that contribute at leading order to
quark-flavour violating transitions. Using the strong scale PETs, we define a
set of portal currents that couple hidden sectors to QCD, and construct portal
chiral perturbation theories ($\chi$PTs) that relate these currents to the
light pseudoscalar mesons. We estimate the coefficients of the portal $\chi$PT
Lagrangian that are not fixed by SM observations using non-perturbative
matching techniques and give a complete list of the resulting one- and
two-meson portal interactions. From those, we compute transition amplitudes for
three golden channels that are used in hidden sector searches at fixed target
experiments: i) charged kaon decay into a charged pion and a spin zero
messenger, ii) charged kaon decay into a charged lepton and a spin one half
messenger, and iii) neutral pion decay into a photon and a spin one messenger.
Finally, we compare these amplitudes to specific expressions for models
featuring light scalar particles, axion-like particles, heavy neutral leptons,
and dark photons.


  Long-ranged electrostatic interactions in electrolytes modify their contact
angles on charged substrates in a scale and geometry dependent manner. For
angles measured at scales smaller than the typical Debye screening length, the
wetting geometry near the contact line must be explicitly considered. Using
variational and asymptotic methods, we derive new transcendental equations for
the contact angle that depend on the electrostatic potential only at the three
phase contact line. Analytic expressions are found in certain limits and
compared with predictions for contact angles measured with lower resolution. An
estimate for electrostatic contributions to {\it line} tension is also given.


  We investigate to what extent Fatou set, Julia set and escaping set of
transcendental semigroup is respectively equal to the Fatou set, Julia set and
escaping set of its subsemigroup. We define partial fundamental set and
fundamental set of transcendental semigroup and on the basis of this set, we
prove that Fatou set and escaping set of transcendental semigroup $ S $ are
non-empty.


  Using holographic-fluid techniques, we discuss some aspects of the
integrability properties of Einstein's equations in asymptotically anti-de
Sitter spacetimes. We review and we amend the results of 1506.04813 on how
exact four-dimensional Einstein spacetimes, which are algebraically special
with respect to Petrov's classification, can be reconstructed from boundary
data: this is possible if the boundary metric supports a traceless, symmetric
and conserved complex rank-two tensor, which is related to the boundary Cotton
and energy-momentum tensors, and if the hydrodynamic congruence is shearless.
We illustrate the method when the hydrodynamic congruence has vorticity and the
boundary metric has two commuting isometries. This leads to the complete
Plebanski-Demianski family. The structure of the boundary consistency
conditions depict a U(1) invariance for the boundary data, which is reminiscent
of a Geroch-like solution-generating pattern for the bulk.


  Estimators based on non-convex sparsity-promoting penalties were shown to
yield state-of-the-art solutions to the magneto-/electroencephalography (M/EEG)
brain source localization problem. In this paper we tackle the model selection
problem of these estimators: we propose to use a proxy of the Stein's Unbiased
Risk Estimator (SURE) to automatically select their regularization parameters.
The effectiveness of the method is demonstrated on realistic simulations and
$30$ subjects from the Cam-CAN dataset. To our knowledge, this is the first
time that sparsity promoting estimators are automatically calibrated at such a
scale. Results show that the proposed SURE approach outperforms
cross-validation strategies and state-of-the-art Bayesian statistics methods
both computationally and statistically.


  We study the hadronic decays of $\Lambda_{c}^{+}$ to the final states
$\Sigma^{+}\eta$ and $\Sigma^+\eta^\prime$, using an $e^{+}e^{-}$ annihilation
data sample of 567 pb$^{-1}$ taken at a center-of-mass energy of 4.6 GeV with
the BESIII detector at the BEPCII collider. We find evidence for the decays
$\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta$ and $\Sigma^+\eta^\prime$ with
statistical significance of $2.5\sigma$ and $3.2\sigma$, respectively.
Normalizing to the reference decays $\Lambda_c^+\to\Sigma^+\pi^0$ and
$\Sigma^+\omega$, we obtain the ratios of the branching fractions
$\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta)}{{\mathcal
B}(\Lambda_c^+\to\Sigma^+\pi^0)}$ and $\frac{{\mathcal
B}(\Lambda_c^+\to\Sigma^+\eta^\prime)}{{\mathcal
B}(\Lambda_c^+\to\Sigma^+\omega)}$ to be $0.35 \pm 0.16 \pm 0.03$ and $0.86 \pm
0.34 \pm 0.07$, respectively. The upper limits at the 90\% confidence level are
set to be $\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta)}{{\mathcal
B}(\Lambda_c^+\to\Sigma^+\pi^0)}<0.58$ and $\frac{{\mathcal
B}(\Lambda_c^+\to\Sigma^+\eta^\prime)}{{\mathcal
B}(\Lambda_c^+\to\Sigma^+\omega)}<1.2$. Using BESIII measurements of the
branching fractions of the reference decays, we determine $\mathcal
B({\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta})=(0.41\pm0.19\pm0.05)\%$
($<0.68\%$) and $\mathcal
B({\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta'})=(1.34\pm0.53\pm0.21)\%$
($<1.9\%$). Here, the first uncertainties are statistical and the second
systematic. The obtained branching fraction of $\Lambda_c^+\to\Sigma^+\eta$ is
consistent with the previous measurement, and the branching fraction of
$\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta^{\prime}$ is measured for the first
time.


  This chapter presents an approach to embed the input/state/output constraints
in a unified manner into the trajectory design for differentially flat systems.
To that purpose, we specialize the flat outputs (or the reference trajectories)
as Bezier curves. Using the flatness property, the system's inputs/states can
be expressed as a combination of Bezier curved flat outputs and their
derivatives. Consequently, we explicitly obtain the expressions of the control
points of the inputs/states Bezier curves as a combination of the control
points of the flat outputs. By applying desired constraints to the latter
control points, we find the feasible regions for the output Bezier control
points i.e. a set of feasible reference trajectories.


  It is well established that to ensure or certify the robustness of a neural
network, its Lipschitz constant plays a prominent role. However, its
calculation is NP-hard. In this note, by taking into account activation regions
at each layer as new constraints, we propose new quadratically constrained MIP
formulations for the neural network Lipschitz estimation problem. The solutions
of these problems give lower bounds and upper bounds of the Lipschitz constant
and we detail conditions when they coincide with the exact Lipschitz constant.


  Characterisation protocols have so far played a central role in the
development of noisy intermediate-scale quantum (NISQ) computers capable of
impressive quantum feats. This trajectory is expected to continue in building
the next generation of devices: ones that can surpass classical computers for
particular tasks -- but progress in characterisation must keep up with the
complexities of intricate device noise. A missing piece in the zoo of
characterisation procedures is tomography which can completely describe
non-Markovian dynamics over a given time frame. Here, we formally introduce a
generalisation of quantum process tomography, which we call process tensor
tomography. We detail the experimental requirements, construct the necessary
post-processing algorithms for maximum-likelihood estimation, outline the
best-practice aspects for accurate results, and make the procedure efficient
for low-memory processes. The characterisation is a pathway to diagnostics and
informed control of correlated noise. As an example application of the
hardware-agnostic technique, we show how its predictive control can be used to
substantially improve multi-time circuit fidelities on superconducting quantum
devices. Our methods could form the core for carefully developed software that
may help hardware consistently pass the fault-tolerant noise threshold.


  The photogalvanic effect -- a rectified current induced by light irradiation
-- requires the intrinsic symmetry of the medium to be sufficiently low, which
strongly limits candidate materials for this effect. In this work we explore
how in Weyl semimetals the photogalvanic effect can be enabled and controlled
by design of the material surface. Specifically, we provide a theory of
ballistic linear and circular photogalvanic current in a Weyl semimetal
spatially confined to a slab under general and variable surface boundary
conditions. The results are applicable to Weyl semimetals with an arbitrary
number of Weyl nodes at radiation frequencies small compared to the energy of
non-linear terms in the dispersion at the Fermi level. The confinement-induced
response is tightly linked to the configuration of Fermi-arc surface states,
specifically the Fermi-arc connectivity and direction of emanation from the
Weyl nodes, thus inheriting the same directionality and sensitivity to boundary
conditions. As a result, the photogalvanic response of the system becomes much
richer than that of an infinite system, and may be tuned via surface
manipulations.


  We have evaluated the contribution to the anomalous magnetic moment of the
electron from six tenth-order Feynman diagrams which contain eighth-order
vacuum-polarization function formed by two light-by-light scattering diagrams
connected by three photons. The integrals are constructed by two different
methods. In the first method the subtractive counter terms are used to deal
with ultraviolet (UV) singularities together with the requirement of
gauge-invariance. In the second method, the Ward-Takahashi identity is applied
to the light-by-light scattering amplitudes to eliminate UV singularities.
Numerical evaluation confirms that the two methods are consistent with each
other within their numerical uncertainties. Combining the two results
statistically and adding small contribution from the muons and/or tau leptons,
we obtain $ 0.000 399 9 (18) (\alpha/\pi)^5$. We also evaluated the
contribution to the muon $g-2$ from the same set of diagrams and found $ -1.263
44 (14) (\alpha/\pi)^5$.


  Hidden parameters are latent variables in reinforcement learning (RL)
environments that are constant over the course of a trajectory. Understanding
what, if any, hidden parameters affect a particular environment can aid both
the development and appropriate usage of RL systems. We present an unsupervised
method to map RL trajectories into a feature space where distance represents
the relative difference in system behavior due to hidden parameters. Our
approach disentangles the effects of hidden parameters by leveraging a
recurrent neural network (RNN) world model as used in model-based RL. First, we
alter the standard world model training algorithm to isolate the hidden
parameter information in the world model memory. Then, we use a metric learning
approach to map the RNN memory into a space with a distance metric
approximating a bisimulation metric with respect to the hidden parameters. The
resulting disentangled feature space can be used to meaningfully relate
trajectories to each other and analyze the hidden parameter. We demonstrate our
approach on four hidden parameters across three RL environments. Finally we
present two methods to help identify and understand the effects of hidden
parameters on systems.


  Pulsar radio emission is modelled as a sum of two completely polarized
non-orthogonal modes with the randomly varying Stokes parameters and intensity
ratio. The modes are the result of polarization evolution of the original
natural waves in the hot magnetized weakly inhomogeneous plasma of pulsar
magnetosphere. In the course of wave mode coupling, the linearly polarized
natural waves acquire purely orthogonal elliptical polarizations. Further on,
as the waves pass through the cyclotron resonance, they become non-orthogonal.
The pulse-to-pulse fluctuations of the final polarization characteristics and
the intensity ratio of the modes are attributed to the temporal fluctuations in
the plasma flow.
  The model suggested allows to reproduce the basic features of the
one-dimensional distributions of the individual-pulse polarization
characteristics. Besides that, propagation origin of pulsar polarization
implies a certain correlation between the mode ellipticity and position angle.
On a qualitative level, for different sets of parameters, the expected
correlations appear compatible with the observed ones. Further theoretical
studies are necessary to establish the quantitative correspondence of the model
to the observational results and to develop a technique of diagnostics of
pulsar plasma on this basis.


  Braitenberg vehicles could be mentioned as the seminal elements for cognitive
studies in robotics fields especially neurorobotics to invent more smart
robots. Motion detection of dynamic objects could be taken as one of the most
inspiring abilities into account which can lead to evolve more intelligent
Braitenberg vehicles. In this paper, a new neuronal circuit is established in
order to detect curved movements of the objects wandering around Braitenberg
vehicles. Modular structure of the novel circuit provides the opportunity to
expand the model into huge sensory-biosystems. Furthermore, robust performance
of the circuit against epileptic seizures is beholden to simultaneous
utilization of excitatory and inhibitory stimuli in the circuit construction.
Also, straight movements, as special case of curved movements could be tracked.
PIONEER, with due attention to its suitable neurosensors, is used as a
Braitenberg vehicle for empirical evaluations. Simulated results and practical
experiments are applied to this vehicle in order to verify new achievements of
the curved trajectory detector.


  Hom gives an example of a knot with vanishing Upsilon invariant but nonzero
epsilon invariant. We build more such knots that are linearly independent in
the smooth concordance group.


  The photometric and morphological properties, as well as the star formation
history, of the Draco dwarf spheroidal galaxy are analyzed on the basis of wide
field, CCD photometry of the resolved stars covering about 1deg^2. No
metallicity gradient is detected. The star surface density distribution can be
fitted by a single exponential law of scale-length a=5'.0+/-0'.1. The central
surface magnitude is mu_V=24.4+/-0.5 and the core radius r_c=7'.5+/- 0.'3
(equivalent to r_c=175+/-7 pc). Within errors, the same scale-lengths are found
for the density profiles along the semi-major axis and the semi-minor axis
(re-scaled to semi-major axis units, using the ellipticity of the galaxy) of
Draco. There are hence no evidences of a tidal-tail associated to Draco. The
tidal radius of the galaxy is found to be r_t~42' (~1 kpc). The possibility
that the large mass-to-light relation in Draco could be accounted for by a
convenient spatial orientation is rejected, which implies that other mechanisms
(e.g., dark matter) are required.
  The stellar population of Draco is mainly old. Although some intermediate-age
population is present in Draco, most of the star formation (up to 90%) took
place before ~10 Gyr ago. No significant star formation activity is detected in
the last ~2 Gyr. Two methods ("partial model" and "subgiant") have been used to
investigate the star formation history of Draco.


  We consider checkpointing strategies that minimize the number of
recomputations needed when performing discrete adjoint computations using
multistage time-stepping schemes, which requires computing several substeps
within one complete time step. In this case we propose two algorithms that can
generate optimal checkpointing schedules under weak assumptions. The first is
an extension of the seminal Revolve algorithm adapted to multistage schemes.
The second algorithm, named CAMS, is developed based on dynamic programming,
and it requires the least number of recomputations when compared with other
algorithms. The CAMS algorithm is made publicly available in a library with
bindings to C and Python. Numerical results illustrate that the proposed
algorithms can deliver up to two times the speedup compared with that of
classical Revolve. Moreover, we discuss a tailored implementation of an adjoint
computation that is arguably better suited for mature scientific computing
libraries by avoiding the central control assumed by the original checkpointing
strategy. The proposed algorithms have been adopted by the PETSc TSAdjoint
library. Their performance has been demonstrated with a large-scale
PDE-constrained optimization problem on a leadership-class supercomputer.


  We hypothesise that all electroweak symmetry breaking terms such as fermion
masses and the W and Z gauge boson masses arise radiatively from just one
explicit symmetry breaking term in the Lagrangian. Our hypothesis is motivated
by the lack of experimental support and the lack of predictivity of the
standard symmetry breaking scenario. We construct a simple model which
illustrates our ideas. We also discuss the possible importance of scale
invariance.


  SDSS J091709.55+463821.8 (hereafter J0917+4638) is the lowest surface gravity
white dwarf (WD) currently known, with log g = 5.55 +/- 0.05 (M ~ 0.17 M_sun;
Kilic et al. 2007a,b). Such low-mass white dwarfs (LMWDs) are believed to
originate in binaries that evolve into WD/WD or WD/neutron star (NS) systems.
An optical search for J0917+4638's companion showed that it must be a compact
object with a mass >= 0.28 M_sun (Kilic 2007b). Here we report on Green Bank
Telescope 820 MHz and XMM-Newton X-ray observations of J0917+4638 intended to
uncover a potential NS companion to the LMWD. No convincing pulsar signal is
detected in our radio data. Our X-ray observation also failed to detect X-ray
emission from J0917+4638's companion, while we would have detected any of the
millisecond radio pulsars in 47 Tuc. We conclude that the companion is almost
certainly another WD.


  Decision making in dense traffic can be challenging for autonomous vehicles.
An autonomous system only relying on predefined road priorities and considering
other drivers as moving objects will cause the vehicle to freeze and fail the
maneuver. Human drivers leverage the cooperation of other drivers to avoid such
deadlock situations and convince others to change their behavior. Decision
making algorithms must reason about the interaction with other drivers and
anticipate a broad range of driver behaviors. In this work, we present a
reinforcement learning approach to learn how to interact with drivers with
different cooperation levels. We enhanced the performance of traditional
reinforcement learning algorithms by maintaining a belief over the level of
cooperation of other drivers. We show that our agent successfully learns how to
navigate a dense merging scenario with less deadlocks than with online planning
methods.


  When a broadband signal propagates through a dispersive medium, some
frequency components move faster than the center of the pulse. This leads to
the appearance of precursors, transient signals that emerge from the medium
earlier than the main part of the pulse and seem to propagate superluminally.
Here, we investigate the microscopic origin of precursors in a minimal setup:
an array of qubits coupled to a waveguide. The linear transmission function
only converges to that of a continuous medium for large qubit numbers.
Nevertheless, the dispersion produced by only two qubits is enough to produce
oscillatory transients. Precursors are best observed under conditions of
electromagnetically-induced transparency, as the center of the pulse is
significantly delayed. Under these conditions, just a single qutrit is enough
to generate a precursor. Our results pave the way towards dispersion
engineering of light with just a few qubits, and can be realized with
superconducting qubits coupled to transmission lines or atoms coupled to
optical waveguides.


  Based on photometric data of the central parts of eight globular clusters and
one open cluster presented by An and his collaborators, we select red
horizontal branch (RHB) stars in the (g-r)0-g0 diagram and make a statistical
study of the distributions of their colors and absolute magnitudes in the SDSS
ugriz system. Meanwhile, absolute magnitudes in the Johnson VRI system are
calculated through the translation formulae between gri and VRI in the
literature. The calibrations of absolute magnitude as functions of metallicity
and age are established by linear regressions of the data.
  It is found that metallicity coefficients in these calibrations decrease,
while age coefficients increase, from the blue $u$ filter to the red $z$
filter. The calibration of Mi= 0.06[Fe/H]+0.040t+0.03 has the smallest scatter
of 0.04 mag, and thus i is the best filter in the $ugriz$ system when RHB stars
are used for distance indicators. The comparison of the MI calibration from our
data with that from red clump stars indicates that the previous suggestion that
the $I$ filter is better than the V filter in distance determination may not be
true because of its significant dependence on age.


  We investigate and quantify the observed scatter in the empirical
relationship between the broad line region size R and the luminosity of the
active galactic nucleus (AGN), in order to better understand its origin. This
study is motivated by the indispensable role of this relationship in the mass
estimation of cosmologically distant black holes, but may also be relevant to
the recently proposed application of this relationship for measuring cosmic
distances. We study six nearby reverberation-mapped AGN for which simultaneous
UV and optical monitoring data exist. We also examine the long-term optical
luminosity variations of Seyfert 1 galaxy NGC 5548 and employ Monte Carlo
simulations to study the effects of the intrinsic variability of individual
objects on the scatter in the global relationship for a sample of ~40 AGN. We
find the scatter in this relationship has a correctable dependence on color.
For individual AGN, the size of the Hbeta emitting region has a steeper
dependence on the nuclear optical luminosity than on the UV luminosity, that
can introduce a scatter of ~0.08 dex into the global relationship, due the
non-linear relationship between the variations in the ionizing continuum and
those in the optical continuum. Also, our analysis highlights the importance of
understanding and minimizing the scatter in the relationship traced by the
intrinsic variability of individual AGN, since it propagates directly into the
global relationship. We find that using the UV luminosity as a substitute for
the ionizing luminosity can reduce a sizable fraction of the current observed
scatter of ~0.13 dex.


  A novel metric that describes the vulnerability of the measurements in power
system to data integrity attacks is proposed. The new metric, coined
vulnerability index (VuIx), leverages information theoretic measures to assess
the attack effect on the fundamental limits of the disruption and detection
tradeoff. The result of computing the VuIx of the measurements in the system
yields an ordering of the measurements vulnerability based on the level of
exposure to data integrity attacks. This new framework is used to assess the
measurements vulnerability of IEEE test systems and it is observed that power
injection measurements are overwhelmingly more vulnerable to data integrity
attacks than power flow measurements. A detailed numerical evaluation of the
VuIx values for IEEE test systems is provided.


  Information geometry provides differential geometric concepts like a
Riemannian metric, connections and covariant derivatives on spaces of
probability distributions. We discuss here how these concepts apply to quantum
field theories in the Euclidean domain which can also be seen as statistical
field theories. The geometry has a dual affine structure corresponding to
sources and field expectation values seen as coordinates. A key concept is a
new generating functional, which is a functional generalization of the
Kullback-Leibler divergence. From its functional derivatives one can obtain
connected as well as one-particle irreducible correlation functions. It also
encodes directly the geometric structure, i. e. the Fisher information metric
and the two dual connections, and it determines asymptotic probabilities for
field configurations through Sanov's theorem.


  We give a bijective proof of a result by R.~Mantaci and F.~Rakotondrajao from
2003, regarding even and odd derangement with a fixed number of excedances. We
refine this result by also considering the set of right-to-left minima.


  This article presents a weakly supervised machine learning method, which we
call DAS-N2N, for suppressing strong random noise in distributed acoustic
sensing (DAS) recordings. DAS-N2N requires no manually produced labels (i.e.,
pre-determined examples of clean event signals or sections of noise) for
training and aims to map random noise processes to a chosen summary statistic,
such as the distribution mean, median or mode, whilst retaining the true
underlying signal. This is achieved by splicing (joining together) two fibres
hosted within a single optical cable, recording two noisy copies of the same
underlying signal corrupted by different independent realizations of random
observational noise. A deep learning model can then be trained using only these
two noisy copies of the data to produce a near fully-denoised copy. Once the
model is trained, only noisy data from a single fibre is required. Using a
dataset from a DAS array deployed on the surface of the Rutford Ice Stream in
Antarctica, we demonstrate that DAS-N2N greatly suppresses incoherent noise and
enhances the signal-to-noise ratios (SNR) of natural microseismic icequake
events. We further show that this approach is inherently more efficient and
effective than standard stop/pass band and white noise (e.g., Wiener) filtering
routines, as well as a comparable self-supervised learning method based on
masking individual DAS channels. Our preferred model for this task is
lightweight, processing 30 seconds of data recorded at a sampling frequency of
1000 Hz over 985 channels (approx. 1 km of fiber) in $<$1 s. Due to the high
noise levels in DAS recordings, efficient data-driven denoising methods, such
as DAS-N2N, will prove essential to time-critical DAS earthquake detection,
particularly in the case of microseismic monitoring.


  Human behaviour is heterogeneous and temporally fluctuates. Many studies have
focused on inter-event time (IET) fluctuations and have reported that the IET
distributions have a long-tailed distribution, which cannot be explained by a
stationary Poisson point process. Such phenomenon observed in IET distributions
are known as burstiness. Burstiness has also been reported for human physical
activity, but the mechanism underlying it has not been clarified. In this
study, we collected human physical activity data while specifying the age of
the subjects and their situations (for example, children's play and adults'
housework), and we analysed their event time-series data. We confirmed the
burstiness in both children and adults. For the first time, burstiness studied
in physical activities of children between the ages 2 and 5. We also confirmed
that the characteristics of the IET distribution are unique to each activity
situation. Our results may be critical in the identification of the burstiness
mechanisms in human physical activity.


  We study the ascent of granular-sized magnetic bubbles from the solar
photosphere through the chromosphere into the transition region and above, for
the first time. Such events occurred in a flux emerging region in NOAA 11850 on
September 25, 2013. During that time, the first co-observing campaign between
the Swedish 1-m Solar Telescope and the IRIS spacecraft was carried out.
Simultaneous observations of the chromospheric H$\alpha$ 656.28 nm and
\ion{Ca}{2} 854.2 nm lines, plus the photospheric \ion{Fe}{1} 630.25 nm line,
were made with the CRISP spectropolarimeter at the SST reaching a spatial
resolution of 0."14. At the same time, IRIS was performing a four-step dense
raster of the said emerging flux region, taking slit-jaw images at 133 (C~{\sc
ii}, transition region), 140 (\ion{Si}{4}, transition region), 279.6
(\ion{Mg}{2} k, core, upper chromosphere), and 283.2 nm (\ion{Mg}{2} k, wing,
photosphere). Spectroscopy of several lines was performed by the IRIS
spectrograph in the far and near ultraviolet, of which we have used the
\ion{Si}{4} 140.3 and the \ion{Mg}{2} k 279.6 nm lines. Coronal images from the
Atmospheric Imaging Assembly of the Solar Dynamics Observatory were used to
investigate the possible coronal signatures of the flux emergence events. The
photospheric and chromospheric properties of small-scale emerging magnetic
bubbles have been described in detail in Ortiz et al. (2014). Here we are able
to follow such structures up to the transition region. We describe the
properties, including temporal delays, of the observed flux emergence in all
layers. We believe this may be an important mechanism of transporting energy
and magnetic flux from subsurface layers to the transition region and corona.


  Nicolas Monod showed that the evaluation map $$H^*_m(G\curvearrowright
G/P)\longrightarrow H^*_m(G)$$ between the measurable cohomology of the action
of a connected semisimple Lie group $G$ on its Furstenberg boundary $G/P$ and
the measurable cohomology of $G$ is surjective with a non-trivial kernel in all
degrees below a constant depending on $G$ and less than or equal to the rank of
$G$ plus $2$. When we were looking for explicit representatives of classes in
this kernel, we were astonished to discover that some of these nontrivial
classes have trivial alternation. In this paper, we refine Monod's result by
identifying the non-alternating and alternating cohomology classes in this
kernel. As a consequence, we show that $H^*_m(G)$ is isomorphic to the
alternating measurable cohomology of $G$ acting on $G/P$ in all even degrees
$$H^{2k}_{m,\mathrm{alt}}(G\curvearrowright G/P)\cong H^{2k}_m(G),$$ for a
majority of Lie groups, namely those for which the longest element of the Weyl
group acts as $-1$ on the Lie algebra of a maximal split torus $A$ in $G$.


  In this paper, we present a new cognitive radio (CR) scenario when the
primary user (PU) operates under more than one transmit power levels. Different
from the existing studies where PU is assumed to have only one constant
transmit power, the new consideration well matches the practical standards,
i.e., IEEE 802.11 Series, GSM, LTE, LTE-A, etc., as well as the adaptive power
concept that has been studied over the past decades. The primary target in this
new CR scenario is, of course, still to detect the presence of PU. However,
there appears a secondary target as to identify the PU's transmit power level.
Compared to the existing works where the secondary user (SU) only senses the
``on-off'' status of PU, recognizing the power level of PU achieves more
``cognition", and could be utilized to protect different powered PU with
different interference levels. We derived quite many closed-form results for
either the threshold expressions or the performance analysis, from which many
interesting points and discussions are raised. We then further study the
cooperative sensing strategy in this new cognitive scenario and show its
significant difference from traditional algorithms. Numerical examples are
provided to corroborate the proposed studies.


  Motivated by the recent experiments indicating superconductivity in
metal-decorated graphene sheets, we investigate their quasi-particle structure
within the framework of an effective tight-binding Hamiltonian augmented by
appropriate BCS-like pairing terms for p-type order parameter. The normal state
band structure of graphene is modified not only through interaction with
adsorbed metal atoms, but also due to the folding of bands at Brillouin zone
boundaries resulting from a $\sqrt{3}\times\sqrt{3}R30^{\circ}$ reconstruction.
Several different types of pairing symmetries are analyzed utilizing
Nambu-Gorkov Green's function techniques to show that $p+ip$-symmetric
nearest-neighbor pairing yields the most enhanced superconducting gap. The
character of the order parameter depends on the nature of the atomic orbitals
involved in the pairing process and exhibits interesting angular and radial
asymmetries. Finally, we suggest a method to distinguish between singlet and
triplet type superconductivity in the presence of magnetic substitutional
impurities using scanning tunneling spectroscopy.


  A vison is an excitation of the Kitaev spin liquid which carries a $\mathbb
Z_2$ gauge flux. While immobile in the pure Kitaev model, it becomes a
dynamical degree of freedom in the presence of perturbations. We study an
isolated vison in the isotropic Kitaev model perturbed by a small external
magnetic field $h$, an offdiagonal exchange interactions $\Gamma$ and a
Heisenberg coupling $J$. In the ferromagnetic Kitaev model, the dressed vison
obtains a dispersion linear in $\Gamma$ and $h$ and a fully universal low-$T$
mobility, $\mu=6 v_m^2/T^{2}$, where $v_m$ is the velocity of Majorana
fermions. In contrast, in the antiferromagnetic Kitaev model interference
effects suppress the coherent propagation and an incoherent Majorana-assisted
hopping leads to a $T$-independent mobility. The motion of a single vison due
to Heisenberg interactions is strongly suppressed for both signs of the Kitaev
coupling. Vison bands in the antiferromagnetic Kitaev models can be topological
and may lead to a characteristic features in thermal Hall effects in Kitaev
materials.


  We report the detection of the millisecond pulsar B1257+12 with the Chandra
X-ray Observatory. In a 20 ks exposure we detected 25 photons from the pulsar,
with energies between 0.4 and 2.0 keV, corresponding to the flux F_X=(4.4+/-
0.9)*10^{-15} ergs s^{-1} cm^{-2} in this energy range. The X-ray spectrum can
be described by a power-law model with photon index Gamma = 2.8 and luminosity
L_X \approx 2.5*10^{29} ergs s^{-1} in the 0.3--8 keV band, for a plausible
distance of 500 pc and hydrogen column density N_H=3*10^{20} cm^{-2}.
Alternatively, the spectrum can be fitted by a blackbody model with kT ~ 0.22
keV and projected emitting area ~2000 m^2. If the thermal X-rays are emitted
from two symmetric polar caps, the bolometric luminosity of the two caps is 2
L_bol ~ 3*10^{29} ergs s^{-1}. We compared our results with the data on other
30 millisecond pulsars observed in X-rays and found that the apparent X-ray
efficiency of PSR B1257+12, L_X/Edot ~ 3*10^{-5} for d=500 pc, is lower than
those of most of millisecond pulsars. This might be explained by an unfavorable
orientation of the X-ray pulsar beam if the radiation is magnetospheric, or by
strong asymmetry of polar caps if the radiation is thermal (e.g., one of the
polar caps is much brighter than the other and remains invisible for most part
of the pulsar period). Alternatively, it could be attributed to absorption of
X-rays in circumpulsar matter, such as a flaring debris disk left over after
formation of the planetary system around the pulsar.


  The next generation Internet is deemed to be heterogeneous in nature and
mobile devices connected to the Internet are expected to be equipped with
different wireless network interfaces. As seamless mobility is important in
such networks, handover between different network types, called vertical
handover, is an important issue in such networks. While proposing standards
like Mobile IPv6 (MIPv6) and Proxy Mobile IPv6 (PMIPv6) for mobility management
protocols, one important challenge being addressed by IETF work groups and the
research community is flow mobility in multi-homed heterogeneous wireless
networks. In this paper we propose and analyze a block prefix mechanism for
flow mobility in PMIPv6 and conducted extensive analytical and simulation
studies to compare the proposed mechanism with existing prefix based mechanisms
for flow mobility in PMIPv6 reported in terms of important performance metrics
such as handover latency, average hop delay, packet density, signaling cost and
packet loss. Both analytical and simulation results demonstrate that the
proposed mechanism outperforms the existing flow mobility management procedures
using either shared or unique prefixes.


  We study in a bottom-up approach the theoretically consistent description of
additional resonances in the electroweak sector beyond the discovered Higgs
boson as simplified models. We focus on scalar and tensor resonances. Our
formalism is suited for strongly coupled models, but can also be applied to
weakly interacting theories. The spurious degrees of freedom of tensor
resonances that would lead to bad high-energy behavior are treated using a
generalization of the Stuckelberg formalism. We calculate scattering amplitudes
for vector-boson and Higgs boson pairs. The high-energy region is regulated by
the T-matrix unitarization procedure, leading to amplitudes that are well
behaved on the whole phase space. We present numerical results for complete
partonic processes that involve resonant vector-boson scattering, for the
current and upcoming runs of LHC.


  We provide a new and significantly shorter optimality proof of recent
quantified Tauberian theorems, both in the setting of vector-valued functions
and of $C_0$-semigroups, and in fact our results are also more general than
those currently available in the literature. Our approach relies on a novel
application of the open mapping theorem.


  Backtracking (i.e., reverse execution) helps the user of a debugger to
naturally think backwards along the execution path of a program, and thinking
backwards makes it easy to locate the origin of a bug. So far backtracking has
been implemented mostly by state saving or by checkpointing. These
implementations, however, inherently do not scale. Meanwhile, a more recent
backtracking method based on reverse-code generation seems promising because
executing reverse code can restore the previous states of a program without
state saving. In the literature, there can be found two methods that generate
reverse code: (a) static reverse-code generation that pre-generates reverse
code through static analysis before starting a debugging session, and (b)
dynamic reverse-code generation that generates reverse code by applying dynamic
analysis on the fly during a debugging session. In particular, we espoused the
latter one in our previous work to accommodate non-determinism of a program
caused by e.g., multi-threading. To demonstrate the usefulness of our dynamic
reverse-code generation, this article presents a case study of various
backtracking methods including ours. We compare the memory usage of various
backtracking methods in a simple but nontrivial example, a bounded-buffer
program. In the case of non-deterministic programs such as this bounded-buffer
program, our dynamic reverse-code generation outperforms the existing
backtracking methods in terms of memory efficiency.


  The effect of nuclear interactions on measurable net-proton number
fluctuations in heavy ion collisions at the SIS18/GSI accelerator is
investigated. The state of the art UrQMD model including interaction potentials
is employed. It is found that the nuclear forces enhance the baryon number
cumulants, as predicted from grand canonical thermodynamical models. The effect
however is smeared out for proton number fluctuations due to iso-spin
randomization and global baryon number conservation, which decreases the
cumulant ratios. For a rapidity acceptance window larger than $\Delta y> 0.4$
the effects of global baryon number conservation dominate and all cumulant
ratios are significantly smaller than 1.


  We consider the high-resolution seismic imaging method called full-waveform
inversion (FWI). FWI is a data fitting method aimed at inverting for subsurface
mechanical parameters. Despite the large adoption of FWI by the academic and
industrial communities, and many successful results, FWI still suffers from
severe limitations. From a mathematical standpoint, FWI is a large scale
PDE-constrained optimization problem. The misfit function that is used, which
measures the discrepancy between observed seismic data and data calculated
through the solution of a wave propagation problem, is non-convex. After
discretization, the size of the FWI problem requires the use of local
optimization solvers, which are prone to converge towards local minima. Thus
the success of FWI strongly depends on the choice of the initial model to
ensure the convergence towards the global minimum of the misfit function.
  This limitation has been the motivation for a large variety of strategies.
Among the different methods that have been investigated, the use of optimal
transport (OT) distances-based misfit functions has been recently promoted. The
leading idea is to benefit from the inherent convexity of OT distances with
respect to dilation and translation to render the FWI problem more convex.
However, the application of OT distances in the framework of FWI is not
straightforward, as seismic data is signed, while OT has been developed for the
comparison of probability measures.
  The purpose of this study is to review two methods that were developed to
overcome this difficulty. Both have been successfully applied to field data in
an industrial framework. Both make it possible to better exploit the seismic
data, alleviating the sensitivity to the initial model and to various
conventional workflow steps, and reducing the uncertainty attached to the
subsurface mechanical parameters inversion.


  We calculate the gravitational wave spectrum produced by magneto-hydrodynamic
turbulence in a first order phase transitions. We focus in particular on the
role of decorrelation of incompressible (solenoidal) homogeneous isotropic
turbulence, which is dominated by the sweeping effect. The sweeping effect
describes that turbulent decorrelation is primarily due to the small scale
eddies being swept with by large scale eddies in a stochastic manner. This
effect reduces the gravitational wave signal produced by incompressible MHD
turbulence by around an order of magnitude compared to previous studies.
Additionally, we find a more complicated dependence for the spectral shape of
the gravitational wave spectrum on the energy density sourced by solenoidal
modes (magnetic and kinetic). The high frequency tail follows either a
$k^{-5/3}$ or a $k^{-8/3}$ power law for large and small solenoidal turbulence
density parameter, respectively. Further, magnetic helicity tends to increase
the gravitational wave energy at low frequencies. Moreover, we show how
solenoidal modes might impact the gravitational wave spectrum from dilatational
modes e.g. sound waves. We find that solenoidal modes greatly affect the shape
of the gravitational wave spectrum due to the sweeping effect on the
dilatational modes. For a high velocity flow, one expects a $k^{-2}$ high
frequency tail, due to sweeping. In contrast, for a low velocity flow and a
sound wave dominated flow, we expect a $k^{-3}$ high frequency tail. If neither
of these limiting cases is realized, the gravitational wave spectrum may be a
broken power law with index between -2 and -3, extending up to the frequency at
which the source is damped by viscous dissipation.


  From a minimum of total energy of celestial bodies, their basic parameters
are obtained. The steady-state values of the mass, radius, and temperature of
stars and white dwarfs, as well as masses of pulsars are calculated. The
luminosity and giromagnetic ratio of celestial bodies are estimated. All the
obtained values are in a satisfactory agreement with observation data.


  Recent observations with the Chandra X-ray telescope continue to detect X-ray
emission from the transient GW170817. In a total exposure of 96.6 ks, performed
between March 9 and March 16 2020 (935 d to 942 d after the merger), a total of
8 photons are measured at the source position, corresponding to a significance
of about 5 sigma. Radio monitoring with the Australian Telescope Compact Array
(ATCA) shows instead that the source has faded below our detection threshold
(<33 uJy, 3 sigma). By assuming a constant spectral index beta=0.585, we derive
an unabsorbed X-ray flux of approximately 1.4E-15 erg/cm^2/s, higher than
earlier predictions, yet still consistent with a simple structured jet model.
We discuss possible scenarios that could account for prolonged emission in
X-rays. The current dataset appears consistent both with energy injection by a
long-lived central engine and with the onset of a kilonova afterglow, arising
from the interaction of the sub-relativistic merger ejecta with the surrounding
medium. Long-term monitoring of this source will be essential to test these
different models.


  In this work we obtain three radial solutions of a biharmonic stationary
Schr\"odinger equation, being one positive, one negative and one that changes
sign. The Dual Decompostion Method is used to split the natural second order
Sobolev space considered in order to apply the appropriate variational
approach.


  We present observational evidence of apparent plasma rotational motions in
the feet of a solar prominence. Our study is based on spectroscopic
observations taken in the He I 1083.0 nm multiplet with the Tenerife Infrared
Polarimeter attached to the German Vacuum Tower Telescope. We recorded a time
sequence of spectra with 34 s cadence placing the slit of the spectrograph
almost parallel to the solar limb and crossing two feet of an intermediate
size, quiescent hedgerow prominence. The data show opposite Doppler shifts, +/-
6 km/s, at the edges of the prominence feet. We argue that these shifts may be
interpreted as prominence plasma rotating counterclockwise around the vertical
axis to the solar surface as viewed from above. The evolution of the prominence
seen in EUV images taken with the Solar Dynamic Observatory provided us clues
to interpret the results as swirling motions. Moreover, time-distance images
taken far from the central wavelength show plasma structures moving parallel to
the solar limb with velocities of about 10-15 km/s. Finally, the shapes of the
observed intensity profiles suggest the presence of, at least, two components
at some locations at the edges of the prominence feet. One of them is typically
Doppler shifted (up to 20 km/s) with respect to the other, thus suggesting the
existence of supersonic counter-streaming flows along the line-of-sight.


  We investigate the possibility of constraining primordial non-Gaussianity
using the 3D bispectrum of Ly-alpha forest. The strength of the quadratic
non-Gaussian correction to an otherwise Gaussian primordial gravitational field
is assumed to be dictated by a single parameter fnl. We present the first
prediction for bounds on fnl using Ly-alpha flux spectra along multiple lines
of sight. The 3D Ly-$\alpha$ transmitted flux field is modeled as a biased
tracer of the underlying matter distribution sampled along 1D skewers
corresponding to quasars sight lines. The precision to which fnl can be
constrained depends on the survey volume, pixel noise and aliasing noise
(arising from discrete sampling of the density field). We consider various
combinations of these factors to predict bounds on fnl. We find that in an
idealized situation of full sky survey and negligible Poisson noise one may
constrain fnl ~ 23 in the equilateral limit. Assuming a Ly-alpha survey
covering large parts of the sky (k_{min} = 8 * 10^{-4} Mpc^{-1}) and with a
quasar density of \bar n = 5 * 10^{-3} Mpc^{-2} it is possible to constrain fnl
~ 100 for equilateral configurations. The possibility of measuring fnl at a
precision comparable to LSS studies maybe useful for joint constraining of
inflationary scenarios using different data sets.


  Recently, the MINOS collaboration reported an anomaly that the mass-squared
difference and mixing angle of $\bar{\nu}_\mu$ $\leftrightarrow$
$\bar{\nu}_\tau$ are both different from that of $\nu_\mu$ $\leftrightarrow$
$\nu_\tau$. In this paper, based on the framework of neutrino oscillations,
terms that break the Lorentz symmetry are used as perturbation to explain this
anomaly and satisfactory results are got. Remarkably, some surprising
conclusions, one of which is that in the high energy limit (hundreds of GeV)
neutrino oscillation pattern will be independent of energy, are also arrived.


  We study unstable epitaxy on singular surfaces using continuum equations with
a prescribed slope-dependent surface current. We derive scaling relations for
the late stage of growth, where power law coarsening of the mound morphology is
observed. For the lateral size of mounds we obtain $\xi \sim t^{1/z}$ with $z
\geq 4$. An analytic treatment within a self-consistent mean-field
approximation predicts multiscaling of the height-height correlation function,
while the direct numerical solution of the continuum equation shows
conventional scaling with z=4, independent of the shape of the surface current.


  Let $a,b,c$ be non-zero integers and $f(x)=ax^n+bx^m+c$ be a trinomial of
degree $n$. We surveyed the irreducibility criteria of $f(x)$ over rational
numbers.


  Bargaining networks model social or economic situations in which agents seek
to form the most lucrative partnership with another agent from among several
alternatives. There has been a flurry of recent research studying Nash
bargaining solutions (also called 'balanced outcomes') in bargaining networks,
so that we now know when such solutions exist, and also that they can be
computed efficiently, even by market agents behaving in a natural manner. In
this work we study a generalization of Nash bargaining, that models the
possibility of unequal 'bargaining powers'. This generalization was introduced
in [KB+10], where it was shown that the corresponding 'unequal division' (UD)
solutions exist if and only if Nash bargaining solutions exist, and also that a
certain local dynamics converges to UD solutions when they exist. However, the
bound on convergence time obtained for that dynamics was exponential in network
size for the unequal division case. This bound is tight, in the sense that
there exists instances on which the dynamics of [KB+10] converges only after
exponential time. Other approaches, such as the one of Kleinberg and Tardos, do
not generalize to the unsymmetrical case. Thus, the question of computational
tractability of UD solutions has remained open. In this paper, we provide an
FPTAS for the computation of UD solutions, when such solutions exist. On a
graph G=(V,E) with weights (i.e. pairwise profit opportunities) uniformly
bounded above by 1, our FPTAS finds an \eps-UD solution in time
poly(|V|,1/\eps). We also provide a fast local algorithm for finding \eps-UD
solution, providing further justification that a market can find such a
solution.


  The main purposes of this paper are to establish and exploit the result that,
over a complete (Noetherian) local ring $R$ of prime characteristic for which
the Frobenius homomorphism $f$ is finite, the appropriate restrictions of the
Matlis-duality functor provide an equivalence between the category of left
modules over the Frobenius skew polynomial ring $R[x,f]$ that are Artinian as
$R$-modules and the category of right $R[x,f]$-modules that are Noetherian as
$R$-modules.


  Given a finite simplicial graph $\Gamma=(V,E)$ with a vertex-labelling
$\varphi:V\rightarrow\left\{\text{non-trivial finitely generated
groups}\right\}$, the graph product $G_\Gamma$ is the free product of the
vertex groups $\varphi(v)$ with added relations that imply elements of adjacent
vertex groups commute. For a quasi-isometric invariant $\mathcal{P}$, we are
interested in understanding under which combinatorial conditions on the graph
$\Gamma$ the graph product $G_\Gamma$ has property $\mathcal{P}$. In this
article our emphasis is on number of ends of a graph product $G_\Gamma$. In
particular, we obtain a complete characterization of number of ends of a graph
product of finitely generated groups.


  The propagation of electrons and photons can respectively have the
spin-momentum locking effect which correlates the spin with the linear
momentum. For the surface electrons in three-dimensional topological insulators
(TIs), their spin is locked to the transport direction. For photons in optical
fibers and photonic waveguides, they carry transverse spin angular momentum
(SAM) which is also locked to the propagation direction. A direct connection
between the electronic and the optical spins occurs in TIs with lifted spin
degeneracy, which leads to spin-dependent selection rules of optical
transitions and results in phenomena such as circular photogalvanic effect
(CPGE). Here, we demonstrate an optoelectronic device that integrates a TI with
a photonic waveguide. Interaction between the photons in the
transverse-magnetic (TM) mode of the waveguide, which carries transverse SAM,
and the surface electrons in a Bi2Se3 layer generates a directional,
spin-polarized photocurrent. Because of optical spin-momentum locking, the
device works in a non-reciprocal way such that changing the light propagation
direction reverses the photon spin and thus the direction of the photocurrent
in the TI. This novel device provides a directional interface that directly
converts the photon propagation path to the direction and spin polarization of
the photo-excited surface current in the TI. It represents a new way of
implementing coupled spin-orbit interaction between electrons and photons and
may lead to significant applications in opto-spintronics and quantum
information processing.


  Roads are connecting line between different places, and used daily. Roads'
periodic maintenance keeps them safe and functional. Detecting and reporting
the existence of potholes to responsible departments can help in eliminating
them. This study deployed and tested on different deep learning architecture to
detect potholes. The images used for training were collected by cellphone
mounted on the windshield of the car, in addition to many images downloaded
from the internet to increase the size and variability of the database. Second,
various object detection algorithms are employed and compared to detect
potholes in real-time like SDD-TensorFlow, YOLOv3Darknet53 and YOLOv4Darknet53.
YOLOv4 achieved the best performance with 81% recall, 85% precision and 85.39%
mean Average Precision (mAP). The speed of processing was 20 frame per second.
The system was able to detect potholes from a range on 100 meters away from the
camera. The system can increase the safety of drivers and improve the
performance of self-driving cars by detecting pothole time ahead.


  The integration of generative artificial intelligence (AI) into architectural
design has witnessed a significant evolution, marked by the recent advancements
in AI to generate text, images, and 3D models. However, no models exist for
text-to-parametric models that are used in architectural design for generating
various design options, including free-form designs, and optimizing the design
options. This study creates and investigates an innovative application of
generative AI in parametric modeling by leveraging a customized Text-to-Visual
Programming (Text2VP) GPT derived from GPT-4. The primary focus is on
automating the generation of graph-based visual programming workflows,
including parameters and the links among the parameters, through AI-generated
scripts, accurately reflecting users' design intentions and allowing the users
to change the parameter values interactively. The Text2VP GPT customization
process utilizes detailed and complete documentation of the visual programming
language components, example-driven few-shot learning, and specific
instructional guides. Our testing demonstrates Text2VP's capability to generate
working parametric models. The paper also discusses the limitations of Text2VP;
for example, more complex parametric model generation introduces higher error
rates. This research highlights the potential of generative AI in visual
programming and parametric modeling and sets a foundation for future
enhancements to handle more sophisticated and intricate modeling tasks
effectively. The study aims to allow designers to create and change design
models without significant effort in learning a specific programming language
such as Grasshopper.


  Study of the forecasting models using large scale microblog discussions and
the search behavior data can provide a good insight for better understanding
the market movements. In this work we collected a dataset of 2 million tweets
and search volume index (SVI from Google) for a period of June 2010 to
September 2011. We perform a study over a set of comprehensive causative
relationships and developed a unified approach to a model for various market
securities like equity (Dow Jones Industrial Average-DJIA and NASDAQ-100),
commodity markets (oil and gold) and Euro Forex rates. We also investigate the
lagged and statistically causative relations of Twitter sentiments developed
during active trading days and market inactive days in combination with the
search behavior of public before any change in the prices/ indices. Our results
show extent of lagged significance with high correlation value upto 0.82
between search volumes and gold price in USD. We find weekly accuracy in
direction (up and down prediction) uptil 94.3% for DJIA and 90% for NASDAQ-100
with significant reduction in mean average percentage error for all the
forecasting models.


  Implicit feedback is widely explored by modern recommender systems. Since the
feedback is often sparse and imbalanced, it poses great challenges to the
learning of complex interactions among users and items. Metric learning has
been proposed to capture user-item interactions from implicit feedback, but
existing methods only represent users and items in a single metric space,
ignoring the fact that users can have multiple preferences and items can have
multiple properties, which leads to potential conflicts limiting their
performance in recommendation. To capture the multiple facets of user
preferences and item properties while resolving their potential conflicts, we
propose the novel framework of Multi-fAcet Recommender networks with Spherical
optimization (MARS). By designing a cross-facet similarity measurement, we
project users and items into multiple metric spaces for fine-grained
representation learning, and compare them only in the proper spaces.
Furthermore, we devise a spherical optimization strategy to enhance the
effectiveness and robustness of the multi-facet recommendation framework.
Extensive experiments on six real-world benchmark datasets show drastic
performance gains brought by MARS, which constantly achieves up to 40\%
improvements over the state-of-the-art baselines regarding both HR and nDCG
metrics.


  A new method allowing calculation of the stability of chelate complexes with
Mg2+ ion in water have been developed. The method is based on two-stage scheme
for the complex formation. The first stage is the ligand transfer from an
arbitrary point of the solution to the second solvation shell of the Mg2+ ion.
At this stage the ligand is considered as a charged or neutral rigid body. The
second stage takes into account disruption of coordinate bonds between Mg2+ and
water molecules from the first solvation shell and formation of the bonds
between the ligand and the Mg2+ ion. This effect is considered using the
quantum chemical modeling. It has been revealed that the main contribution to
the free energy of the complex formation is caused by the disruption/formation
of the coordinate bonds between Mg2+, water molecules and the ligand. Another
important contribution to the complex formation energy is change of
electrostatic interactions in water solvent upon the ligand binding with Mg2+
ion. For all complexes under investigation the reasonable (in frame of 2
kcal/mol) agreement between calculated and experimental values are achieved.


  Gravitational-wave observations of black hole ringdowns are commonly used to
characterize binary merger remnants and to test general relativity. These
analyses assume linear black hole perturbation theory, in particular that the
ringdown can be described in terms of quasinormal modes even for times
approaching the merger. Here we investigate a nonlinear effect during the
ringdown, namely how a mode excited at early times can excite additional modes
as it is absorbed by the black hole. This is a third-order secular effect: the
change in the black-hole mass causes a shift in the mode spectrum, so that the
original mode is projected onto the new ones. Using nonlinear simulations, we
study the ringdown of a spherically-symmetric scalar field around an
asymptotically anti-de Sitter black hole, and we find that this
"absorption-induced mode excitation" (AIME) is the dominant nonlinear effect.
We show that this effect takes place well within the nonadiabatic regime, so we
can analytically estimate it using a sudden mass-change approximation. Adapting
our estimation technique to asymptotically-flat Schwarzschild black holes, we
expect AIME to play a role in the analysis and interpretation of current and
future gravitational wave observations.


  We present a demonstration of service-based trajectory planning for a drone
delivery system in a multi-drone skyway network. We conduct several experiments
using Crazyflie drones to collect the drone's position data, wind speed and
direction, and wind effects on voltage consumption rates. The experiments are
run for a varying number of recharging stations, wind speed, and wind direction
in a multi-drone skyway network. Demo: https://youtu.be/zEwqdtEmmiw


  Recently were introduced physical billiards where a moving particle is a hard
sphere rather than a point as in standard mathematical billiards. It has been
shown that in the same billiard tables the physical billiards may have totally
different dynamics than mathematical billiards. This difference appears if the
boundary of a billiard table has visible singularities (internal corners if the
billiard table is two-dimensional), i.e. the particle may collide with these
singular points. Here, we consider the collision of a hard ball with a visible
singular point and demonstrate that the motion of the smooth ball after
collision with a visible singular point is indeed the one that was used in the
studies of physical billiards. So such collision is equivalent to the elastic
reflection of hard ball's center off a sphere with the center at the singular
point and the same radius as the radius of the moving particle.


  We examine the possibility to extend leap second extrapolation for a near
future based on some periodic terms in the Earth's rotation changes. The IERS
data, covering the interval from 1962.15 to 2006.95, are analyzed. The
difference $\Delta T$ is extrapolated till to 2035 and compared with the IERS
extrapolated values to the 2012. It can be seen that for the interval from 2006
to 2024 only 1 leap seconds (negative) will be operated.


  We construct Schroedinger-like solutions of the Vasiliev higher spin theory
in D>3 dimension. Symmetries of such solutions and the linearised equation of
motion for the scalar on such backgrounds are analysed. We further propose
Galilean invariant bosonic and fermionic field theories that could be dual to
the two parity invariant higher spin theories on the Schroedinger-like
background respectively. The discussion is phrased mainly in D=4 dimension,
while similar constructions follow straightforwardly in higher dimensions.


  In the Maxwell--Chern-Simons theory coupled to $N_f$ flavors of 4-component
fermions (or even number of 2-component fermions) we construct the
gauge-covariant effective potential written in terms of two order parameters
which are able to probe the breakdown of chiral symmetry and parity. In the
absence of the bare Chern-Simons term, we show that the chiral symmetry is
spontaneously broken for fermion flavors $N_f$ below a certain finite critical
number $N_f^c$, while the parity is not broken spontaneously. This chiral phase
transition is of the second order. In the presence of the bare Chern-Simons
term, on the other hand, the chiral phase transition associated with the
spontaneous breaking of chiral symmetry is shown to continue to exist, although
the parity is explicitly broken. However it is shown that the existence of the
bare Chern-Simons term changes the order of the chiral transition into the
first order, no matter how small the bare Chern-Simons coefficient may be. This
gauge-invariant result is consistent with that recently obtained by the
Schwinger-Dyson equation in the non-local gauge.


  Finding minimum dominating set and maximum independent set for graphs in the
classical online setup are notorious due to their disastrous $\Omega(n)$ lower
bound of the competitive ratio that even holds for interval graphs, where $n$
is the number of vertices. In this paper, inspired by Newton number, first, we
introduce the independent kissing number $\zeta$ of a graph. We prove that the
well known online greedy algorithm for dominating set achieves optimal
competitive ratio $\zeta$ for any graph. We show that the same greedy algorithm
achieves optimal competitive ratio $\zeta$ for online maximum independent set
of a class of graphs with independent kissing number $\zeta$. For minimum
connected dominating set problem, we prove that online greedy algorithm
achieves an asymptotic competitive ratio of $2(\zeta-1)$, whereas for a family
of translated convex objects the lower bound is $\frac{2\zeta-1}{3}$. Finally,
we study the value of $\zeta$ for some specific families of geometric objects:
fixed and arbitrary oriented unit hyper-cubes in $I\!\!R^d$, congruent balls in
$I\!\!R^3$, fixed oriented unit triangles, fixed and arbitrary oriented regular
polygons in $I\!\!R^2$. For each of these families, we also present lower
bounds of the minimum connected dominating set problem.


  Assessing code comment quality is known to be a difficult problem. A number
of coding style guidelines have been created with the aim to encourage writing
of informative, readable, and consistent comments. However, it is not clear
from the research to date which specific aspects of comments the guidelines
cover (e.g., syntax, content, structure). Furthermore, the extent to which
developers follow these guidelines while writing code comments is unknown.
  We analyze various style guidelines in Java and Python and uncover that the
majority of them address more the content aspect of the comments rather than
syntax or formatting, but when considering the different types of information
developers embed in comments and the concerns they raise on various online
platforms about the commenting practices, existing comment conventions are not
yet specified clearly enough, nor do they adequately cover important concerns.
We also analyze commenting practices of developers in diverse projects to see
the extent to which they follow the guidelines. Our results highlight the
mismatch between developer commenting practices and style guidelines, and
provide several focal points for the design and improvement of comment quality
checking tools.


  We introduce valence bond fluctuations, or bipartite fluctuations associated
to bond-bond correlation functions, to characterize quantum spin liquids and
their entanglement properties. Using analytical and numerical approaches, we
find an identical scaling law between valence bond fluctuations and
entanglement entropy in the two-dimensional Kitaev spin model and in
one-dimensional chain analogues. We also show how these valence bond
fluctuations can locate quantum phase transitions between the three gapped and
the gapless Majorana semi-metal phases in the honeycomb model. We then study
the effect of a uniform magnetic field along the 111 direction opening a gap in
the intermediate phase which becomes topological. We still obtain a robust
signal to characterize the transitions towards the three gapped phases. The
linear scaling behavior of such bipartite fluctuations in two dimensions is
also distinguishable from the one in the Neel magnetic state.


  For models of non-interacting fermions moving within sites arranged on a
surface in three dimensional space, there can be obstructions to finding
localized Wannier functions. We show that such obstructions are $K$-theoretic
obstructions to approximating almost commuting, complex-valued matrices by
commuting matrices, and we demonstrate numerically the presence of this
obstruction for a lattice model of the quantum Hall effect in a spherical
geometry. The numerical calculation of the obstruction is straightforward, and
does not require translational invariance or introducing a flux torus.
  We further show that there is a $Z_2$ index obstruction to approximating
almost commuting self-dual matrices by exactly commuting self-dual matrices,
and present additional conjectures regarding the approximation of almost
commuting real and self-dual matrices by exactly commuting real and self-dual
matrices. The motivation for considering this problem is the case of physical
systems with additional antiunitary symmetries such as time reversal or
particle-hole conjugation.
  Finally, in the case of the sphere--mathematically speaking three almost
commuting Hermitians whose sum of square is near the identity--we give the
first quantitative result showing this index is the only obstruction to finding
commuting approximations. We review the known non-quantitative results for the
torus.


  Research has shown that recommender systems are typically biased towards
popular items, which leads to less popular items being underrepresented in
recommendations. The recent work of Abdollahpouri et al. in the context of
movie recommendations has shown that this popularity bias leads to unfair
treatment of both long-tail items as well as users with little interest in
popular items. In this paper, we reproduce the analyses of Abdollahpouri et al.
in the context of music recommendation. Specifically, we investigate three user
groups from the LastFM music platform that are categorized based on how much
their listening preferences deviate from the most popular music among all
LastFM users in the dataset: (i) low-mainstream users, (ii) medium-mainstream
users, and (iii) high-mainstream users. In line with Abdollahpouri et al., we
find that state-of-the-art recommendation algorithms favor popular items also
in the music domain. However, their proposed Group Average Popularity metric
yields different results for LastFM than for the movie domain, presumably due
to the larger number of available items (i.e., music artists) in the LastFM
dataset we use. Finally, we compare the accuracy results of the recommendation
algorithms for the three user groups and find that the low-mainstreaminess
group significantly receives the worst recommendations.


  The leading-order hadronic contribution to the muon magnetic moment anomaly
$a_\mu\equiv (g_\mu-2)/2$, calculated using a dispersion integral of $e^+e^-$
annihilation data and $\tau$ data, is briefly reviewed. This contribution has
the largest uncertainty to the predicted value of $a_\mu$, which differs from
the direct measurement by $\sim 3.6 (2.4)$ standard deviations for the $e^+e^-
(\tau)$ based analysis. Recent results and main open issues on the subject are
discussed.


  Quantum collision models (CMs) provide advantageous case studies for
investigating major issues in open quantum systems theory, and especially
quantum non-Markovianity. After reviewing their general definition and
distinctive features, we illustrate the emergence of a CM in a familiar quantum
optics scenario. This task is carried out by highlighting the close connection
between the well-known input-output formalism and CMs. Within this quantum
optics framework, usual assumptions in the CMs' literature - such as
considering a bath of non-interacting yet initially correlated ancillas - have
a clear physical origin.


  A new method for finding solutions of the nonlinear Shr\"{o}dinger equation
is proposed. Comutative multiplicative group of the nonlinear transformations,
which operate on stationary localized solutions, enables a consideration of
fractal subspaces in the solution space, stability and deterministic chaos. An
increase of the transmission rate at the optical fiber communications can be
based on new forms of localized stationary solutions, without significant
change of input power. The estimated transmission rate is 50 Gbit/s, for
certain available soliton transmission systems.


  For T an abelian compact Lie group, we give a description of T-equivariant
K-theory with complex coefficients in terms of equivariant cohomology. In the
appendix we give applications of this by extending results of Chang-Skjelbred
and Goresky-Kottwitz-MacPherson from equivariant cohomology to equivariant
K-theory.


  We introduce a new map from polynomials orthogonal on the unit circle to
polynomials orthogonal on the real axis. This map is closely related with the
theory of CMV matrices. It contains an arbitrary parameter which leads to a
linear operator pencil. We show that the little and big -1 Jacobi polynomials
are naturally obtained under this map from the Jacobi polynomials on the unit
circle.


  The extended main sequence turn offs (eMSTOs) of several young to
intermediate age clusters are examined in the Magellanic Clouds and the Milky
Way. We explore the effects of extended star formation (eSF) and a range of
stellar rotation rates on the behavior of the color-magnitude diagram (CMD),
paying particular attention to the MSTO. We create synthetic stellar
populations based on MESA stellar models to simulate observed Hubble Space
Telescope and Gaia star cluster data. We model the effect of rotation as a
non-parametric distribution, allowing for maximum flexibility. In our models
the slow rotators comprise the blueward, and fast rotators the redward portion
of the eMSTO. We simulate data under three scenarios: non-rotating eSF, a range
of rotation rates with a single age, and a combination of age and rotation
effects. We find that two of the five clusters (the youngest and oldest) favor
an age spread, but these also achieve the overall worst fits of all clusters.
The other three clusters show comparable statistical evidence between rotation
and an age spread. In all five cases, a rotation rate distribution alone is
capable of qualitatively matching the observed eMSTO structure. In future work,
we aim to compare our predicted Vsin(i) with observations in order to better
constrain the physics related to stellar rotation.


  We have identified nine new SNR candidates in M74 with [S II]/H$\alpha$
$\geq$ 0.4 as the basic criterion. We obtain [S II]/H$\alpha$ ratio in the
range from 0.40 to 0.91 and H$\alpha$ intensities from 2.8 $\times$ $10^{-15}$
erg cm$^{-2}$ s$^{-1}$ to 1.7 $\times$ $10^{-14}$ erg cm$^{-2}$ s$^{-1}$. We
also present spectral follow-up observations of the SNR candidates and can
confirm only three of them (SNR2, SNR3, and SNR5). The lack of confirmation for
the rest might be due to the contamination by the nearby H II emission regions
as well as due to the inaccurate positioning of the long slit on these objects.
In addition, we search the $Chandra$ Observatory archival data for the X-ray
counterparts to the optically identified candidates. We find positional
coincidence with only three SNR candidates, SNR1, SNR2, and SNR8. The spectrum
of SNR2 yields a shock temperature of 10.8 keV with an ionization timescale of
1.6 $\times$ 10$^{10}$ s cm$^{-3}$ indicating a relatively young remnant in an
early Sedov phase which is not supported by our optical wavelength analysis.
Given the high luminosity of 10$^{39}$ erg s$^{-1}$ and the characteristics of
the X-ray spectrum, we favor an Ultra Luminous X-ray Source interpretation for
this source associated with an SNR. We calculate an X-ray flux upper limit of
9.0 $\times$ $10^{-15}$ erg cm$^{-2}$ s$^{-1}$ for the rest of the SNRs
including spectroscopically identified SNR3 and SNR5.


  We investigate energetic stability and dissociation dynamics of water
adsorption at the LaAlO3 surface of the n-type LaAlO3/SrTiO3 (LAO/STO)
interface and its effect on electronic properties of the interface by carrying
out first-principles electronic structure calculations. In an ambient
atmosphere at room temperature the configuration of 1 monolayer (ML) of water
molecules including 3/4 ML of dissociated water molecules adsorbed at the
surface is found to be most stable, the configuration of 1 ML of dissociated
water molecules is metastable. Water molecule dissociation induces a shift-up
of the valence band maximum (VBM) of the LAO surface, reducing the gap between
the VBM of the LAO surface and the conduction band minimum of the STO. For the
LAO/STO interface with three LAO unit-cell layers, once the coverage of
dissociated water molecules reaches 1/2 ML the gap is closed, the interface
becomes metallic and the carrier density at the LAO/STO interface increases
with increasing the coverage of dissociated water molecules. Our findings
suggest two ways to control the conductivity at the LAO/STO interface: (I)
insulator-metal transition by adsorbing a mount of water at the bare surface;
(II) carrier density change by the transition between the most stable and the
metastable adsorption configurations for 1 ML coverage in an ambient atmosphere
at room temperature.


  In this work, we have developed an elegant algorithm to study the
cosmological consequences from a huge class of quantum field theories (i.e.
superstring theory, supergravity, extra dimensional theory, modified gravity
etc.), which are equivalently described by soft attractors in the effective
field theory framework. In this description we have restricted our analysis for
two scalar fields - dilaton and Higgsotic fields minimally coupled with
Einstein gravity, which can be generalized for any arbitrary number of scalar
field contents with generalized non-canonical and non-minimal interactions. We
have explicitly used $R^2$ gravity, from which we have studied the attractor
and non-attractor phase by exactly computing two point, three point and four
point correlation functions from scalar fluctuations using In-In
(Schwinger-Keldysh) and $\delta {\cal N}$ formalism. We have also presented
theoretical bounds on the amplitude, tilt and running of the primordial power
spectrum, various shapes (equilateral, squeezed, folded kite or counter
collinear) of the amplitude as obtained from three and four point scalar
functions, which are consistent with observed data. Also the results from two
point tensor fluctuations and field excursion formula are explicitly presented
for attractor and non-attractor phase. Further, reheating constraints, scale
dependent behaviour of the couplings and the dynamical solution for the dilaton
and Higgsotic fields are also presented. New sets of consistency relations
between two, three and four point observables are also presented, which shows
significant deviation from canonical slow roll models. Additionally, three
possible theoretical proposals have presented to overcome the tachyonic
instability at the time of late time acceleration. Finally, we have also
provided the bulk interpretation from the three and four point scalar
correlation functions for completeness.


  We perform a comparison of two jet clusterization algorithms. The first one
is the standard Durham algorithm and the second one is a global optimization
scheme, Deterministic Annealing, often used in clusterization problems, and
adapted to the problem of jet identification in particle production by high
energy collisions; in particular we study hadronic jets in WW production by
high energy electron positron scattering. Our results are as follows. First, we
find that the two procedures give basically the same output as far as the
particle clusterization is concerned. Second, we find that the increase of CPU
time with the particle multiplicity is much faster for the Durham jet
clustering algorithm in comparison with Deterministic Annealing. Since this
result follows from the higher computational complexity of the Durham scheme,
it should not depend on the particular process studied here and might be
significant for jet physics at LHC as well.


  We compute linear and quadratic static density response functions of
three-dimensional Yukawa liquids by applying an external perturbation potential
in molecular dynamics simulations. The response functions are also obtained
from the equilibrium fluctuations (static structure factors) in the system via
the fluctuation-dissipation theorems. The good agreement of the quadratic
response functions, obtained in the two different ways confirms the quadratic
fluctuation-dissipation theorem. We also find that the three-point structure
function may be factorizable into two-point structure functions, leading to a
cluster representation of the equilibrium triplet correlation function.


  Let $G$ be a finite group and $M(G)$ be the subgroup of $G$ generated by all
non-central elements of $G$ that lie in the conjugacy classes of the smallest
size. Recently several results have been proved regarding the nilpotency class
of $M(G)$ and $F(M(G))$, where $F(M(G))$ denotes the Fitting subgroup of
$M(G)$. We prove some conditional results regarding the nilpotency class of
$M(G)$.


  The effect of the Berendsen thermostat on the dynamical properties of bulk
SPC/E water is tested by generating power spectra associated with fluctuations
in various observables. The Berendsen thermostat is found to be very effective
in preserving temporal correlations in fluctuations of tagged particle
quantities over a very wide range of frequencies. Even correlations in
fluctuations of global properties, such as the total potential energy, are
well-preserved for time periods shorter than the thermostat time constant.
Deviations in dynamical behaviour from the microcanonical limit do not,
however, always decrease smoothly with increasing values of the thermostat time
constant but may be somewhat larger for some intermediate values of $\tau_B$,
specially in the supercooled regime, which are similar to time scales for slow
relaxation processes in bulk water.


  This note complements the author's recent paper "Robust representation
learning with feedback for single image deraining" by providing heuristically
theoretical explanations on the mechanism of representation learning with
feedback, namely an essential merit of the works presented in this recent
article. This note facilitates understanding of key points in the mechanism of
representation learning with feedback.


  We report on follow-up observations of 20 short-duration gamma-ray bursts
performed in g'r'i'z'JHKs with the seven-channel imager GROND between mid-2007
and the end of 2010. This is one of the most comprehensive data sets on GRB
afterglow observations of short bursts published so far. In three cases GROND
was on target within less than 10 min after the trigger, leading to the
discovery of the afterglow of GRB 081226A and its faint underlying host galaxy.
In addition, GROND was able to image the optical afterglow and follow the
light-curve evolution in further five cases, GRBs 090305, 090426, 090510,
090927, and 100117A. In all other cases optical/NIR upper limits can be
provided on the afterglow magnitudes.


  The continued operation of the Wide-field Infrared Survey Explorer (WISE)
combined with several ground-based optical transient surveys (e.g., CRTS,
ASAS-SN and PTF) offer an unprecedented opportunity to explore the dust
structures in luminous AGNs. We use these data for a mid-IR dust reverberation
mapping (RM) study of 87 archetypal Palomar-Green quasars at $z\lesssim0.5$. To
cope with various contaminations of the photometry data and the sparse time
sampling of the light curves, procedures to combine these datasets and retrieve
the dust RM signals have been developed. We find $\sim$70% of the sample (with
a completeness correction, up to 95%) have convincing mid-IR time-lags in the
WISE W1 ($\sim3.4~\mu m$) and W2 ($\sim4.5~\mu m$) bands and they are
proportional to the square root of the AGN luminosity. Combined with previous
K-band ($\sim2.2~\mu m$) RM results in the literature, the inferred dust
emission size ratios are $R_{K}:R_{W1}:R_{W2}=0.6:1:1.2$. Under simple
assumptions, we put preliminary constraints on the projected dust surface
density at these bands and reveal the possibly different torus structures among
hot-dust-deficient, warm-dust-deficient and normal quasars from the
reverberation signals. With multi-epoch Spitzer data and later WISE photometry,
we also explore AGN IR variability at 10--24 $\mu m$ over a 5-year time-scale.
Except for blazars and flat-spectrum radio sources, the majority of AGNs have
typical variation amplitudes at 24 $\mu m$ no more than 10% of that in the W1
band, indicating the dust reverberation signals damp out quickly at longer
wavelengths. In particular, steep-spectrum radio quasars also lack strong 24
$\mu m$ variability, consistent with the unification picture of radio-loud AGN.


  To evaluate Information Retrieval (IR) effectiveness, a possible approach is
to use test collections, which are composed of a collection of documents, a set
of description of information needs (called topics), and a set of relevant
documents to each topic. Test collections are modelled in a competition
scenario: for example, in the well known TREC initiative, participants run
their own retrieval systems over a set of topics and they provide a ranked list
of retrieved documents; some of the retrieved documents (usually the first
ranked) constitute the so called pool, and their relevance is evaluated by
human assessors; the document list is then used to compute effectiveness
metrics and rank the participant systems. Private Web Search companies also run
their in-house evaluation exercises; although the details are mostly unknown,
and the aims are somehow different, the overall approach shares several issues
with the test collection approach.
  The aim of this work is to: (i) develop and improve some state-of-the-art
work on the evaluation of IR effectiveness while saving resources, and (ii)
propose a novel, more principled and engineered, overall approach to test
collection based effectiveness evaluation.
  [...]


  Content moderation at scale faces the challenge of considering local cultural
distinctions when assessing content. While global policies aim to maintain
decision-making consistency and prevent arbitrary rule enforcement, they often
overlook regional variations in interpreting natural language as expressed in
content. In this study, we are looking into how moderation systems can tackle
this issue by adapting to local comprehension nuances. We train large language
models on extensive datasets of media news and articles to create culturally
attuned models. The latter aim to capture the nuances of communication across
geographies with the goal of recognizing cultural and societal variations in
what is considered offensive content. We further explore the capability of
these models to generate explanations for instances of content violation,
aiming to shed light on how policy guidelines are perceived when cultural and
societal contexts change. We find that training on extensive media datasets
successfully induced cultural awareness and resulted in improvements in
handling content violations on a regional basis. Additionally, these
advancements include the ability to provide explanations that align with the
specific local norms and nuances as evidenced by the annotators' preference in
our conducted study. This multifaceted success reinforces the critical role of
an adaptable content moderation approach in keeping pace with the ever-evolving
nature of the content it oversees.