  In this paper we describe the fundamental group-scheme of a proper variety
fibered over an abelian variety with rationally connected fibers over an
algebraically closed field. We use old and recent results for the Nori
fundamental group-scheme, and of finite group-schemes in general to prove that
the kernel of such a fibration is finite, and that the homotopy exact sequence
holds in this case. As an application, we describe the fundamental
group-schemes of certain proper varieties that are connected by curves or are
related to them.


  An important application of haptic technology to digital product development
is in virtual prototyping (VP), part of which deals with interactive planning,
simulation, and verification of assembly-related activities, collectively
called virtual assembly (VA). In spite of numerous research and development
efforts over the last two decades, the industrial adoption of haptic-assisted
VP/VA has been slower than expected. Putting hardware limitations aside, the
main roadblocks faced in software development can be traced to the lack of
effective and efficient computational models of haptic feedback. Such models
must 1) accommodate the inherent geometric complexities faced when assembling
objects of arbitrary shape; and 2) conform to the computation time limitation
imposed by the notorious frame rate requirements---namely, 1 kHz for haptic
feedback compared to the more manageable 30-60 Hz for graphic rendering. The
simultaneous fulfillment of these competing objectives is far from trivial.
  This survey presents some of the conceptual and computational challenges and
opportunities as well as promising future directions in haptic-assisted VP/VA,
with a focus on haptic assembly from a geometric modeling and spatial reasoning
perspective. The main focus is on revisiting definitions and classifications of
different methods used to handle the constrained multibody simulation in
real-time, ranging from physics-based and geometry-based to hybrid and unified
approaches using a variety of auxiliary computational devices to specify,
impose, and solve assembly constraints. Particular attention is given to the
newly developed 'analytic methods' inherited from motion planning and protein
docking that have shown great promise as an alternative paradigm to the more
popular combinatorial methods.


  We present a novel scenario for the formation of carbon-enhanced metal-poor
(CEMP) stars. Carbon enhancement at low stellar metallicities is usually
considered a consequence of faint or other exotic supernovae. An analytical
estimate of cooling times in low-metallicity gas demonstrates a natural bias,
which favours the formation of CEMP stars as a consequence of inhomogeneous
metal mixing: carbon-rich gas has a shorter cooling time and can form stars
prior to a potential nearby pocket of carbon-normal gas, in which star
formation is then suppressed due to energetic photons from the carbon-enhanced
protostars. We demonstrate that this scenario provides a natural formation
mechanism for CEMP stars from carbon-normal supernovae, if inhomogeneous metal
mixing provides carbonicity differences of at least one order of magnitude
separated by >10pc. In our fiducial (optimistic) model, 8% (83%) of observed
CEMP-no stars ([Ba/Fe]<0) can be explained by this formation channel. This new
scenario may change our understanding of the first supernovae and thereby our
concept of the first stars. Future 3D simulations are required to assess the
likelihood of this mechanism to occur in typical high-redshift galaxies.


  We present high speed photometric observations of the eclipsing dwarf nova IP
Peg taken with the triple-beam camera ULTRACAM mounted on the William Herschel
Telescope. The primary eclipse in this system was observed twice in 2004, and
then a further sixteen times over a three week period in 2005. Our observations
were simultaneous in the Sloan u', g' and r' bands. By phase-folding and
averaging our data we make the first significant detection of the white dwarf
ingress in this system and find the phase width of the white dwarf eclipse to
be 0.0935 +/- 0.0003, significantly higher than the previous best value of
between 0.0863 and 0.0918. The mass ratio is found to be q = M2 /M1 = 0.48 +/-
0.01, consistent with previous measurements, but we find the inclination to be
83.8 +/- 0.5 deg, significantly higher than previously reported. We find the
radius of the white dwarf to be 0.0063 +/- 0.0003 solar radii, implying a white
dwarf mass of 1.16 +/- 0.02 solar masses. The donor mass is 0.55 +/- 0.02 solar
masses. The white dwarf temperature is more difficult to determine, since the
white dwarf is seen to vary significantly in flux, even between consecutive
eclipses. This is seen particularly in the u'-band, and is probably the result
of absorption by disc material. Our best estimate of the temperature is 10,000
- 15,000K, which is much lower than would be expected for a CV with this
period, and implies a mean accretion rate of less than 5 times 10^-11 solar
masses per year, more than 40 times lower than the expected rate.


  The Chapman-Enskog method of kinetic theory is applied to two problems of
synchronization of globally coupled phase oscillators. First, a modified
Kuramoto model is obtained in the limit of small inertia from a more general
model which includes ``inertial'' effects. Second, a modified Chapman-Enskog
method is used to derive the amplitude equation for an O(2) Takens-Bogdanov
bifurcation corresponding to the tricritical point of the Kuramoto model with a
bimodal distribution of oscillator natural frequencies. This latter calculation
shows that the Chapman-Enskog method is a convenient alternative to normal form
calculations.


  Given a minimal action $\alpha$ of a countable group on the Cantor set, we
show that the alternating full group $\mathsf{A}(\alpha)$ is non-amenable if
and only if the topological full group $\mathsf{F}(\alpha)$ is $C^*$-simple.
This implies, for instance, that the Elek-Monod example of non-amenable
topological full group coming from a Cantor minimal $\mathbb{Z}^2$-system is
$C^*$-simple.


  A locally small category E is totally distributive (as defined by
Rosebrugh-Wood) if there exists a string of adjoint functors t -| c -| y, where
y : E --> E^ is the Yoneda embedding. Saying that E is lex totally distributive
if, moreover, the left adjoint t preserves finite limits, we show that the lex
totally distributive categories with a small set of generators are exactly the
injective Grothendieck toposes, studied by Johnstone and Joyal. We characterize
the totally distributive categories with a small set of generators as exactly
the essential subtoposes of presheaf toposes, studied by Kelly-Lawvere and
Kennett-Riehl-Roy-Zaks.


  Human-robot interaction can be regarded as a flow between users and robots.
Designing good interaction flows takes a lot of effort and needs to be field
tested. Unfortunately, the interaction flow design process is often very
disjointed, with users experiencing prototypes, designers forming those
prototypes, and developers implementing them as independent processes. In this
paper, we present the Interaction Flow Editor (IFE), a new human-robot
interaction prototyping tool that enables everyday users to create and modify
their own interactions, while still providing a full suite of features that is
powerful enough for developers and designers to create complex interactions. We
also discuss the Flow Engine, a flexible and adaptable framework for executing
robot interaction flows authors through the IFE. Finally, we present our case
study results that demonstrates how older adults, aged 70 and above, can design
and iterate interactions in real-time on a robot using the IFE.


  Task-motion planning (TMP) addresses the problem of efficiently generating
executable and low-cost task plans in a discrete space such that the (initially
unknown) action costs are determined by motion plans in a corresponding
continuous space. However, a task-motion plan can be sensitive to unexpected
domain uncertainty and changes, leading to suboptimal behaviors or execution
failures. In this paper, we propose a novel framework, TMP-RL, which is an
integration of TMP and reinforcement learning (RL) from the execution
experience, to solve the problem of robust task-motion planning in dynamic and
uncertain domains. TMP-RL features two nested planning-learning loops. In the
inner TMP loop, the robot generates a low-cost, feasible task-motion plan by
iteratively planning in the discrete space and updating relevant action costs
evaluated by the motion planner in continuous space. In the outer loop, the
plan is executed, and the robot learns from the execution experience via
model-free RL, to further improve its task-motion plans. RL in the outer loop
is more accurate to the current domain but also more expensive, and using less
costly task and motion planning leads to a jump-start for learning in the real
world. Our approach is evaluated on a mobile service robot conducting
navigation tasks in an office area. Results show that TMP-RL approach
significantly improves adaptability and robustness (in comparison to TMP
methods) and leads to rapid convergence (in comparison to task planning (TP)-RL
methods). We also show that TMP-RL can reuse learned values to smoothly adapt
to new scenarios during long-term deployments.


In this form will appear in Communications in Algebra.


  Background: Multi-articulate prostheses are capable of performing dexterous
hand movements. However, clinically available control strategies fail to
provide users with intuitive, independent and proportional control over
multiple degrees of freedom (DOFs) in real-time. New Method: We detail the use
of a modified Kalman filter (MKF) to provide intuitive, independent and
proportional control over six-DOF prostheses such as the DEKA "LUKE" Arm. Input
features include neural firing rates recorded from Utah Slanted Electrode
Arrays and mean absolute value of intramuscular electromyographic (EMG)
recordings. Ad-hoc modifications include thresholds and non-unity gains on the
output of a Kalman filter. Results: We demonstrate that both neural and EMG
data can be combined effectively. We also highlight that modifications can be
optimized to significantly improve performance relative to an unmodified Kalman
filter. Thresholds significantly reduced unintended movement and promoted more
independent control of the different DOFs. Gain were significantly greater than
one and served to amplify participant effort. Optimal modifications can be
determined quickly offline and translate to functional improvements online.
Using a portable take-home system, participants performed various activities of
daily living. Comparison with Existing Methods: In contrast to pattern
recognition, the MKF allows users to continuously modulate their force output,
which is critical for fine dexterity. The MKF is also computationally efficient
and can be trained in less than five minutes. Conclusions: The MKF can be used
to explore the functional and psychological benefits associated with long-term,
at-home control of dexterous prosthetic hands.


  The theoretical analysis of deep neural networks (DNN) is arguably among the
most challenging research directions in machine learning (ML) right now, as it
requires from scientists to lay novel statistical learning foundations to
explain their behaviour in practice. While some success has been achieved
recently in this endeavour, the question on whether DNNs can be analyzed using
the tools from other scientific fields outside the ML community has not
received the attention it may well have deserved. In this paper, we explore the
interplay between DNNs and game theory (GT), and show how one can benefit from
the classic readily available results from the latter when analyzing the
former. In particular, we consider the widely studied class of congestion
games, and illustrate their intrinsic relatedness to both linear and non-linear
DNNs and to the properties of their loss surface. Beyond retrieving the
state-of-the-art results from the literature, we argue that our work provides a
very promising novel tool for analyzing the DNNs and support this claim by
proposing concrete open problems that can advance significantly our
understanding of DNNs when solved.


  We report on the design and construction of a LED-based fiber calibration
system for large liquid argon time projection detectors. This system was
developed to calibrate the optical systems of the MicroBooNE experiment. As
well as detailing the materials and installation procedure, we provide
technical drawings and specifications so that the system may be easily
replicated in future LArTPC detectors.


  An interrelation between a topological design of network and efficient
algorithm on it is important for its applications to communication or
transportation systems. In this paper, we propose a design principle for a
reliable routing in a store-carry-forward manner based on autonomously moving
message-ferries on a special structure of fractal-like network, which consists
of a self-similar tiling of equilateral triangles. As a collective adaptive
mechanism, the routing is realized by a relay of cyclic message-ferries
corresponded to a concatenation of the triangle cycles and using some good
properties of the network structure. It is recoverable for local accidents in
the hierarchical network structure. Moreover, the design principle is
theoretically supported with a calculation method for the optimal service rates
of message-ferries derived from a tandem queue model for stochastic processes
on a chain of edges in the network. These results obtained from a combination
of complex network science and computer science will be useful for developing a
resilient network system.


  We study the effect of a surface modification at the interface between
metallic electrodes and semiconducting substrate in Semi-Insulating GaAs
(SI-GaAs) based photoconductive emitters (PCE) on the emission of Tera-Hertz
(THz) radiation. We partially etch out 500 nm thick layer of SI-GaAs in grating
like pattern with various periods before the contact deposition. By depositing
the electrodes on the patterned surface, the electrodes follow the contour of
the grating period. This increases the effective contact length of the
electrodes per unit area of the active regions on the PCE. The maxima of the
electric field amplitude of the THz pulses emitted from the patterned surface
are enhanced by up to more than a factor 2 as compared to an un-patterned
surface. We attribute this increase to the increase of the effective contact
length of the electrode due to surface patterning.


  Diffusion-based image synthesis has attracted extensive attention recently.
In particular, ControlNet that uses image-based prompts exhibits powerful
capability in image tasks such as canny edge detection and generates images
well aligned with these prompts. However, vanilla ControlNet generally requires
extensive training of around 5000 steps to achieve a desirable control for a
single task. Recent context-learning approaches have improved its adaptability,
but mainly for edge-based tasks, and rely on paired examples. Thus, two
important open issues are yet to be addressed to reach the full potential of
ControlNet: (i) zero-shot control for certain tasks and (ii) faster adaptation
for non-edge-based tasks. In this paper, we introduce a novel Meta ControlNet
method, which adopts the task-agnostic meta learning technique and features a
new layer freezing design. Meta ControlNet significantly reduces learning steps
to attain control ability from 5000 to 1000. Further, Meta ControlNet exhibits
direct zero-shot adaptability in edge-based tasks without any finetuning, and
achieves control within only 100 finetuning steps in more complex non-edge
tasks such as Human Pose, outperforming all existing methods. The codes is
available in https://github.com/JunjieYang97/Meta-ControlNet.


  This paper investigates the synthesis of distributed economic control
algorithms under which dynamically coupled physical systems are regulated to a
variational equilibrium of a constrained convex game. We study two
complementary cases: (i) each subsystem is linear and controllable; and (ii)
each subsystem is nonlinear and in the strict-feedback form. The convergence of
the proposed algorithms is guaranteed using Lyapunov analysis. Their
performance is verified by two case studies on a multi-zone building
temperature regulation problem and an optimal power flow problem, respectively.


  Over the last four decades, a number of modified gravity theories have been
proposed to study cosmological phenomena as they can provide solutions for some
of the shortcomings of Einstein's gravity in explaining early and late time
accelerations of the observed Universe, the existence of dark matter,
singularities at center of Black holes etc. The theoretical and observational
challenges faced by the $\Lambda$CDM model also point towards the necessity for
looking beyond General Relativity. In this direction, recently $f(\phi, T)$
gravity has been proposed in literature where the non-minimal coupling of the
scalar field $\phi$ with the trace of energy-momentum tensor $T$ has been
introduced in the Einstein-Hilbert action. Considering the Hilltop potential,
we have studied the slow-roll inflation in the framework of $f(\phi, T)$
gravity. It is found that Hilltop inflationary models in $f(\phi, T)$ gravity
are viable when seen in the light of latest Planck data.


  Differential privacy comes equipped with multiple analytical tools for the
design of private data analyses. One important tool is the so-called "privacy
amplification by subsampling" principle, which ensures that a differentially
private mechanism run on a random subsample of a population provides higher
privacy guarantees than when run on the entire population. Several instances of
this principle have been studied for different random subsampling methods, each
with an ad-hoc analysis. In this paper we present a general method that
recovers and improves prior analyses, yields lower bounds and derives new
instances of privacy amplification by subsampling. Our method leverages a
characterization of differential privacy as a divergence which emerged in the
program verification community. Furthermore, it introduces new tools, including
advanced joint convexity and privacy profiles, which might be of independent
interest.


  Braid combing is a procedure defined by Emil Artin to solve the word problem
in braid groups for the first time. It is well-known to have exponential
complexity. In this paper, we use the theory of straight line programs to give
a polynomial algorithm which performs braid combing. This procedure can be
applied to braids on surfaces, providing the first algorithm (to our knowledge)
which solves the word problem for braid groups on surfaces with boundary in
polynomial time and space.
  In the case of surfaces without boundary, braid combing needs to use a
section from the fundamental group of the surface to the braid group. Such a
section was shown to exist by Gon\ccalves and Guaschi, who also gave a
geometric description. We propose an algebraically simpler section, which we
describe explicitly in terms of generators of the braid group, and we show why
the above procedure to comb braids in polynomial time does not work in this
case.


  In this paper, we propose a new minimal path model for minimally interactive
retinal vessel centerline extraction. The main contribution lies at the
construction of a novel coherence-penalized Riemannian metric in a lifted
space, dependently of the local geometry of tubularity and an external
scalar-valued reference feature map. The globally minimizing curves associated
to the proposed metric favour to pass through a set of retinal vessel segments
with low variations of the feature map, thus can avoid the short branches
combination problem and shortcut problem, commonly suffered by the existing
minimal path models in the application of retinal imaging. We validate our
model on a series of retinal vessel patches obtained from the DRIVE and IOSTAR
datasets, showing that our model indeed get promising results.


  Video-based programming tutorials are a popular form of tutorial used by
authors to guide learners to code. Still, the interactivity of these videos is
limited primarily to control video flow. There are existing works with
increased interactivity that are shown to improve the learning experience.
Still, these solutions require setting up a custom recording environment and
are not well-integrated with the playback environment. This paper describes our
integrated ITSS environment and evaluates the ease of authoring and playback of
our interactive programming tutorials. Our environment is designed to run
within the browser sandbox and is less intrusive to record interactivity
actions. We develop a recording approach that tracks the author's interactivity
actions (e.g., typing code, highlighting words, scrolling panels) on the
browser and stored in text and audio formats. We replay these actions using the
recorded artefacts for learners to have a more interactive, integrated and
realistic playback of the author's actions instead of watching video frames.
Our design goals are 1) efficient recording and playback, 2) extensible
interactivity features to help students learn better, and 3) a scalable
web-based environment. Our first user study of 20 participants who carry out
the author tasks agree that it is efficient and easy to author interactive
videos in our environment with no additional software needed. Our second user
study of 84 students using the environment agrees that the increased
interactivity can help them learn better over a video-based tutorial. Our
performance test shows that the environment can scale to support up to 500
concurrent users. We hope our open-source environment enable more educators to
create interactive programming tutorials.


  SrMoO$_3$ is a promising material for its excellent electrical conductivity,
but growing high-quality thin films remains a challenge. Here we synthesized
epitaxial films of SrMoO$_3$ using the molecular beam epitaxy (MBE) technique
under a low oxygen-flow rate. Introduction of SrTiO$_3$ buffer layers of 4--8
unit cells between the film and the (001)-oriented SrTiO$_3$ or KTaO$_3$
substrate was crucial to remove impurities and/or roughness of the film
surface. The obtained film shows improved electrical conductivities as compared
with films obtained by other techniques. The high quality of the SrMoO$_3$ film
is also verified by angle-resolved photoemission spectroscopy (ARPES)
measurements showing clear Fermi surfaces.


  The NRAO Very Long Baseline Array (VLBA) was used at 1.4 GHz to image 20
compact sources in the inner 1-degree radius of the Spitzer VLA First-Look
Survey. Twelve sources were detected with the VLBA, with peak flux densities
above 2 mJy at 9-mas resolution. The positions of these VLBA detections have
been measured in the International Celestial Reference Frame (ICRF) to 1-sigma
accuracies of 8 mas East-West and 4 mas North-South. These positions can help
anchor ancillary data for the First-Look Survey to the ICRF and are being
reported quickly to the community.


  Erd\H{o}s conjectured that for any set $A\subseteq \mathbb{N}$ with positive
lower asymptotic density, there are infinite sets $B,C\subseteq \mathbb{N}$
such that $B+C\subseteq A$. We verify Erd\H{o}s' conjecture in the case that
$A$ has Banach density exceeding $\frac{1}{2}$. As a consequence, we prove
that, for $A\subseteq \mathbb{N}$ with positive Banach density (a much weaker
assumption than positive lower density), we can find infinite $B,C\subseteq
\mathbb{N}$ such that $B+C$ is contained in the union of $A$ and a translate of
$A$. Both of the aforementioned results are generalized to arbitrary countable
amenable groups. We also provide a positive solution to Erd\H{o}s' conjecture
for subsets of the natural numbers that are pseudorandom.


  Recent STAR data for the directed flow of protons, antiprotons, and charged
pions obtained within the beam energy scan program are analyzed within the
parton-hadron-string-dynamics (PHSD and HSD) transport models and a 3-fluid
hydrodynamics (3FD) approach. Both versions of the kinetic approach, HSD and
PHSD, are used to clarify the role of partonic degrees of freedom. The PHSD
results, simulating a partonic phase and its coexistence with a hadronic one,
are roughly consistent with data. The hydrodynamic results are obtained for two
equations of state (EoS), a pure hadronic EoS and an EoS with a crossover type
transition. The latter case is favored by the STAR experimental data. Special
attention is paid to the description of antiproton directed flow based on the
balance of $p\bar{p}$ annihilation and the inverse processes for $p\bar{p}$
pair creation from multimeson interactions. Generally, the semiqualitative
agreement between the measured data and the model results supports the idea of
a crossover type of quark-hadron transition that softens the nuclear EoS but
shows no indication of a first-order phase transition.


  In this paper, a mathematically rigorous solution overturns existing wisdom
regarding New Keynesian Dynamic Stochastic General Equilibrium. I develop a
formal concept of stochastic equilibrium. I prove uniqueness and necessity,
when agents are patient, with general application. Existence depends on
appropriately specified eigenvalue conditions. Otherwise, no solution of any
kind exists. I construct the equilibrium with Calvo pricing. I provide novel
comparative statics with the non-stochastic model of mathematical significance.
I uncover a bifurcation between neighbouring stochastic systems and
approximations taken from the Zero Inflation Non-Stochastic Steady State
(ZINSS). The correct Phillips curve agrees with the zero limit from the trend
inflation framework. It contains a large lagged inflation coefficient and a
small response to expected inflation. Price dispersion can be first or second
order depending how shocks are scaled. The response to the output gap is always
muted and is zero at standard parameters. A neutrality result is presented to
explain why and align Calvo with Taylor pricing. Present and lagged demand
shocks enter the Phillips curve so there is no Divine Coincidence and the
system is identified from structural shocks alone. The lagged inflation slope
is increasing in the inflation response, embodying substantive policy
trade-offs. The Taylor principle is reversed, inactive settings are necessary,
pointing towards inertial policy. The observational equivalence idea of the
Lucas critique is disproven. The bifurcation results from the breakdown of the
constraints implied by lagged nominal rigidity, associated with cross-equation
cancellation possible only at ZINSS. There is a dual relationship between
restrictions on the econometrician and constraints on repricing firms. Thus, if
the model is correct, goodness of fit will jump.


  A novel active negative index metamaterial that derives its gain from an
electron beam is intro- duced. The metamaterial consists of a stack of
equidistant parallel metal plates perforated by a periodic array of holes
shaped as complementary split-ring resonators. It is shown that this structure
supports a negative-index transverse magnetic electromagnetic mode that can
resonantly interact with a relativistic electron beam. Such metamaterial can be
used as a coherent radiation source or a particle accelerator.


  The path decomposition expansion represents the propagator of the
irreversible reaction as a convolution of the first-passage, last-passage and
rebinding time probability densities. Using path integral technique, we give an
elementary, yet rigorous, proof of the path decomposition expansion of the
Green's functions describing the non-reactive case and the irreversible
reaction of an isolated pair of molecules. To this end, we exploit the
connection between boundary value problems and interaction potential problems
with $\delta$- and $\delta'$-function perturbation. In particular, we employ a
known exact summation of a perturbation series to derive exact relations
between the Green's functions of the perturbed and unperturbed problem. Along
the way, we are able to derive a number of additional exact identities that
relate the propagators describing the free-space, the non-reactive as well as
the completely and partially reactive case.


  Membrane scattering in m(atrix) theory is related to dynamics in
three-dimensional $SU(2)$ gauge theory, with transfer of $p^{11}$ being an
instanton process. We calculate the instanton amplitude and find precise
agreement with the amplitude in eleven dimensional supergravity.


  We present high-spatial resolution HST and adaptive optics observations, and
high-sensitivity ISO (ISOCAM & ISOPHOT) observations of a sample of X-ray
selected weak-line (WTTS) and post (PTTS) T Tauri stars located in the nearby
Chamaeleon T and Scorpius-Centaurus OB associations. HST/NICMOS and adaptive
optics observations aimed at identifying substellar companions at separations
>=30 A.U. from the primary stars. No such objects were found within 300 A.U. of
any of the target stars, and a number of faint objects at larger separations
can very likely be attributed to a population of background stars. ISOCAM
observations of 5 to 15 Myr old WTTS and PTTS in ScoCen reveal infrared
excesses which are clearly above photospheric levels, and which have a spectral
index intermediate between that of younger (1 to 5 Myr) T Tauri stars in Cha
and that of pure stellar photospheres. The difference in the spectral index of
the older PTTS in ScoCen compared to the younger classical and WTTS in Cha can
be attributed to a deficiency of smaller size (0.1 to 1mu) dust grains relative
to larger size (~5mu) dust grains in the disks of the PTTS. The lack of small
dust grains is either due to the environment (effect of nearby O stars and
supernova explosions) or due to disk evolution. If the latter is the case, it
would hint that circumstellar disks start to get dust depleted at an age
between 5 to 15 Myr. Dust depletion is very likely related to the build-up of
larger particles (ultimately rocks and planetesimals) and thus an indicator for
the onset of the period of planet formation.


  A new gauge theory of gravity is presented. The theory is constructed in a
flat background spacetime and employs gauge fields to ensure that all relations
between physical quantities are independent of the positions and orientations
of the matter fields. In this manner all properties of the background spacetime
are removed from physics, and what remains are a set of `intrinsic' relations
between physical fields. The properties of the gravitational gauge fields are
derived from both classical and quantum viewpoints. Field equations are then
derived from an action principle, and consistency with the minimal coupling
procedure selects an action that is unique up to the possible inclusion of a
cosmological constant. This in turn singles out a unique form of spin-torsion
interaction. A new method for solving the field equations is outlined and
applied to the case of a time-dependent, spherically-symmetric perfect fluid. A
gauge is found which reduces the physics to a set of essentially Newtonian
equations. These equations are then applied to the study of cosmology, and to
the formation and properties of black holes. The existence of global solutions
enables one to discuss the properties of field lines inside the horizon due to
a point charge held outside it. The Dirac equation is studied in a black hole
background and provides a quick derivation of the Hawking temperature.


  We say that a map $T: S_X\rightarrow S_Y$ between the unit spheres of two
real normed-spaces $X$ and $Y$ is a phase-isometry if it satisfies
\begin{eqnarray*} \{\|T(x)+T(y)\|, \|T(x)-T(y)\|\}=\{\|x+y\|, \|x-y\|\}
\end{eqnarray*} for all $x,y\in S_X$. In the present paper, we show that there
is a phase function $\varepsilon:S_X\rightarrow \{-1,1\}$ such that
$\varepsilon \cdot T$ is an isometry which can be extended a linear isometry on
the whole space $X$ whenever $T$ is surjective, $X=C(K)$ ($K$ is a compact
Hausdorff space) and $Y$ is an arbitrary Banach space. Additionally, if $T$ is
a phase-isometry between the unit spheres of $C(K)$ and $C(\Omega)$, where $K$
and $\Omega$ are compact Hausdorff spaces, we prove that there is a
homeomorphism $\varphi: \Omega\rightarrow K$ such that $T(f)\in\{f\circ
\varphi,-f\circ \varphi\}$ for all $f\in S_{C(K)}$. This also can be seen as a
Banach-Stone type representation for phase-isometries in $C(K)$ spaces.


  It is known that every exotic smooth structure on a simply connected closed
4-manifold is determined by a codimention zero compact contractible Stein
submanifold and an involution on its boundary. Such a pair is called a cork. In
this paper, we construct infinitely many knotted imbeddings of corks in
4-manifolds such that they induce infinitely many different exotic smooth
structures. We also show that we can imbed an arbitrary finite number of corks
disjointly into 4-manifolds, so that the corresponding involutions on the
boundary of the contractible 4-manifolds give mutually different exotic
structures. Furthermore, we construct similar examples for plugs.


  We present results on the synchronization of the helicity in a liquid-metal
Rayleigh-B\'enard (RB) experiment under the influence of a tide-like
electromagnetic forcing with azimuthal wavenumber m=2. We show that for a
critical forcing strength the typical Large Scale Circulation (LSC) in the
cylindrical vessel of aspect ratio unity is entrained by the period of the
tide-like forcing, leading to synchronized helicity oscillations with opposite
signs in two half-spaces. The obtained experimental results are consistent with
and supported by numerical simulations. A similar entrainment mechanism for the
helicity in the solar tachocline may be responsible for the astonishing
synchronization of the solar dynamo by the 11.07-year triple synodic alignment
cycle of the tidally dominant planets Venus, Earth and Jupiter.


  In this paper we develop a theory to describe innovation processes in a
network of interacting units. We introduce a stochastic picture that allows for
the clarification of the role of fluctuations for the survival of innovations
in such a non-linear system. We refer to the theory of complex networks and
introduce the notion of sensitive networks. Sensitive networks are networks in
which the introduction or the removal of a node/vertex dramatically changes the
dynamic structure of the system. As an application we consider interaction
networks of firms and technologies and describe technological innovation as a
specific dynamic process. Random graph theory, percolation, master equation
formalism and the theory of birth and death processes are the mathematical
instruments used in this paper.


  In this paper we study the complex representations of reductive groups over
local non-Archimedean fields. We use the building of the reductive group to
give upper-bounds for the absolute value of the character of an admissible
representation and for the Weyl integration formula for certain regular
elements. The upper-bound for the character of a representation is based on the
alternative description, depending on the building, of the character as given
by R. Meyer and M. Solleveld [MS12]. Once the character and the Weyl
integration formula are related to the building, the upper-bounds will follow
from a similar argument. Both upper-bounds generalize the upper-bounds given by
Harish-Chandra [HC70] to groups defined over fields of positive characteristic.
At last following Harish-Chandra's method we combine both upper-bounds to show
that for a maximal torus $T$ containing a maximal split torus the character is
locally summable on $\{ gtg^{-1} : g\in G,t\in T\}$.


  An important challenge in the field of exponential random graphs (ERGs) is
the fitting of non-trivial ERGs on large graphs. By utilizing fast matrix
block-approximation techniques, we propose an approximative framework to such
non-trivial ERGs that result in dyadic independence (i.e., edge independent)
distributions, while being able to meaningfully model both local information of
the graph (e.g., degrees) as well as global information (e.g., clustering
coefficient, assortativity, etc.) if desired. This allows one to efficiently
generate random networks with similar properties as an observed network, and
the models can be used for several downstream tasks such as link prediction.
Our methods are scalable to sparse graphs consisting of millions of nodes.
Empirical evaluation demonstrates competitiveness in terms of both speed and
accuracy with state-of-the-art methods -- which are typically based on
embedding the graph into some low-dimensional space -- for link prediction,
showcasing the potential of a more direct and interpretable probabalistic model
for this task.


  An analytical model is presented for the postcollapse equilibrium structure
of virialized objects which condense out of a low-density cosmological
background universe, either matter-dominated or flat with a cosmological
constant. This generalizes the model we derived previously for an Einstein-de
Sitter (EdS) universe. The model is based upon the assumption that cosmological
haloes form from the collapse and virialization of top-hat density
perturbations and are spherical, isotropic, and isothermal. This leads to the
prediction of a unique, nonsingular, truncated isothermal sphere (TIS), a
particular solution of the Lane-Emden equation (modified for nonzero
cosmological constant). The size and virial temperature are unique functions of
the mass and redshift of formation of the object for a given background
universe. The central density is roughly proportional to the critical density
of the universe at the epoch of collapse. This TIS model is in good agreement
with observations of the internal structure of dark matter--dominated haloes on
scales ranging from dwarf galaxies to X-ray clusters. It also reproduces many
of the average properties of haloes in simulations of the Cold Dark Matter
(CDM) model to good accuracy, suggesting that it is a useful analytical
approximation for haloes which form from realistic initial conditions. Our TIS
model matches the density profiles of haloes in CDM N-body simulations outside
the innermost region, while avoiding the steep central cusp of the latter which
is in apparent conflict with observations. The TIS model may also be relevant
to nonstandard CDM models, like self-interacting dark matter, recently proposed
to resolve this conflict.


  We study some relation between some geometrically defined classes of
diffeomorphisms between manifolds and the $L_{q,p}$-cohomology of these
manifolds. Some applications to vanishing and non vanishing results in
$L_{q,p}$-cohomology are given.


  We propose that grand minima in solar activity are caused by simultaneous
fluctuations in the meridional circulation and the Babcock-Leighton mechanism
for the poloidal field generation in the flux transport dynamo model. We
present the following results: (a) fluctuations in the meridional circulation
are more effective in producing grand minima; (b) both sudden and gradual
initiations of grand minima are possible; (c) distributions of durations and
waiting times between grand minima seem to be exponential; (d) the coherence
time of the meridional circulation has an effect on the number and the average
duration of grand minima, a coherence time of about 30 years being consistent
with observational data. We also study the occurrence of grand maxima and find
that the distributions of durations and waiting times between grand maxima are
also exponential, like the grand minima. Finally we address the question
whether the Babcock-Leighton mechanism can be operative during grand minima
when there are no sunspots. We show that an alpha-effect restricted to the
upper portions of the convection zone can pull the dynamo out of the grand
minima and can match various observational requirements if the amplitude of
this alpha-effect is suitably fine-tuned.


  As the number of empirical studies increases unprecedentedly in line with
expansions in higher education, theoretical developments in population studies
suffer due to a discoverability crisis of related work. The systematic use of
previous research is common in the medical sciences through various types of
structured reviews. However, these are less common in the social sciences,
despite their potential, especially in cross-disciplinary fields such as
migration. We use Google Scholar to examine the niche of housing research
within migration studies through a broad range of documents. The contribution
of this meta-analysis is threefold. Firstly, we illustrate the association of
keywords across the corpus of literature related to migration and housing and
map the growth of migration literature since the 1960s. Secondly, we highlight
key bridging documents using network measures. Finally, we estimate the
distance in reading time between documents. Our findings suggest that the
corpus of previous work at the intersection of migration and housing consists
of many additive case studies, indicating a gap in integrative approaches
replicable across a growing knowledge landscape.


  The thermodynamics of massless ideal gas of overlap quarks has been
investigated numerically for both zero and nonzero baryon chemical potential
$\mu$. While the parameter M has been shown to be irrelevant in the continuum
limit, it is shown numerically that the continuum limit can be reached with
relatively coarser lattices for certain range of M. Numerical limitation of the
existing method of introduction of chemical potential in the overlap formalism
is discussed. We have also studied the energy density of free domain wall
fermions in the absence of $\mu$ and estimated the extent of lattice in the
fifth dimension $L_5$ for which the overlap results are recovered.
Interestingly, this value of $L_5$ is also minimum for the same range of M
found in the overlap case.


  By utilizing higher harmonics of undulator radiation, harmonic lasing is
helpful in the development of compact x-ray free electron lasers (FELs), i.e.
reducing its costs and sizes. Harmonic lasing of FELs have been experimentally
demonstrated in the low-gain FEL oscillators from terahertz, infrared to
ultraviolet spectral range. Based on the current status and future directions
of short-wavelength FELs in the worldwide, this paper reviews the progresses on
harmonic lasing of x-ray FELs, mainly concentrating on the recently proposed
harmonic lasing of x-ray FEL oscillators and further ideas on harmonic lasing
of single pass x-ray FEL amplifiers.


  We propose an exponential wave integrator sine pseudospectral (EWI-SP) method
for the nonlinear Schr\"{o}dinger equation (NLS) with wave operator (NLSW), and
carry out rigorous error analysis. The NLSW is NLS perturbed by the wave
operator with strength described by a dimensionless parameter
$\varepsilon\in(0,1]$. As $\varepsilon\to0^+$, the NLSW converges to the NLS
and for the small perturbation, i.e. $0<\varepsilon\ll1$, the solution of the
NLSW differs from that of the NLS with a function oscillating in time with
$O(\varepsilon^2)$-wavelength at $O(\varepsilon^2)$ and $O(\varepsilon^4)$
amplitudes for ill-prepared and well-prepared initial data, respectively. This
rapid oscillation in time brings significant difficulties in designing and
analyzing numerical methods with error bounds uniformly in $\varepsilon$. In
this work, we show that the proposed EWI-SP possesses the optimal uniform error
bounds at $O(\tau^2)$ and $O(\tau)$ in $\tau$ (time step) for well-prepared
initial data and ill-prepared initial data, respectively, and spectral accuracy
in $h$ (mesh size) for the both cases, in the $L^2$ and semi-$H^1$ norms. This
result significantly improves the error bounds of the finite difference methods
for the NLSW. Our approach involves a careful study of the error propagation,
cut-off of the nonlinearity and the energy method. Numerical examples are
provided to confirm our theoretical analysis.


  Dynamical phase transitions are defined through non-analyticities of the
survival probability of an out-of-equilibrium time-evolving state at certain
critical times. They ensue from zeros of the corresponding survival amplitude.
By extending the time variable onto the complex domain, we formulate the
complex-time survival amplitude. The complex zeros of this quantity near the
time axis correspond, in the infinite-size limit, to non-analytical points
where the survival probability abruptly vanishes. Our results are numerically
exemplified in the fully-connected transverse-field Ising model, which displays
a symmetry-broken phase delimited by an excited-state quantum phase transition.
A detailed study of the behavior of the complex-time survival amplitude when
the characteristics of the out-of-equilibrium protocol changes is presented.
The influence of the excited-state quantum phase transition is also put into
context.


  The Hodge bundle $\omega$ over a modular curve is a square-root of the
canonical bundle twisted by the cuspidal divisor, or a theta characteristic,
due to the Kodaira--Spencer isomorphism. We prove that, in most cases, a
section of a theta characteristic $\nu$ (or any odd power of it) different from
$\omega$ is a noncongruence modular form. On the other hand, we show how
$\nu\ne\omega$ gives rise to a ``twisted'' analogue of the diagonal period map
to a Siegel threefold, whose difference attributes to the stackiness of the
moduli of abelian surfaces $\mathcal{A}_{2}$. Some questions on the
Brill--Noether theory of the modular curves are answered.


  We discuss the possible cooling of different phonon modes via three wave
mixing interactions of vibrational and optical modes. Since phonon modes
exhibit a variety of dispersion relations or frequency spectra with diverse
spatial structures, depending on the shape and size of the sample, we formulate
our theory in terms of relevant spatial mode functions for the interacting
fields in any given geometry. We discuss the possibility of Dicke like
collective effects in phonon cooling and present explicit results for
simultaneous cooling of two phonon modes via the anti-Stokes up conversions. We
show that the bimodal cooling should be observable experimentally.


  The Internet of Things is a paradigm that refers to the ubiquitous presence
around us of physical objects equipped with sensing, networking, and processing
capabilities that allow them to cooperate with their environment to reach
common goals. However, any threat affecting the availability of IoT
applications can be crucial financially and for the safety of the physical
integrity of users. This feature calls for IoT applications that remain
operational and efficiently handle possible threats. However, designing an IoT
application that can handle threats is challenging for stakeholders due to the
high susceptibility to threats of IoT applications and the lack of modeling
mechanisms that contemplate resilience as a first-class representation. In this
paper, an architectural Design Decision Model for Resilient IoT applications is
presented to reduce the difficulty of stakeholders in designing resilient IoT
applications. Our approach is illustrated and demonstrates the value through
the modeling of a case.


  The spectroscopic parallaxes in the Hipparcos catalogue can be used to
translate absolute stellar fluxes observed at Earth to the fluxes emerging at
the stellar surface for nearby stars. The comparison of these fluxes with the
predictions of theoretical model atmospheres allows us to determine the
effective temperature and the metallicity of the stars. It is suggested that is
possible to study the stellar content of the solar neighbourhood making use of
the large number of ultraviolet spectra in the archive of the IUE satellite.


  Database Management System (DBMS) fuzzing is an automated testing technique
aimed at detecting errors and vulnerabilities in DBMSs by generating, mutating,
and executing test cases. It not only reduces the time and cost of manual
testing but also enhances detection coverage, providing valuable assistance in
developing commercial DBMSs. Existing fuzzing surveys mainly focus on
general-purpose software. However, DBMSs are different from them in terms of
internal structure, input/output, and test objectives, requiring specialized
fuzzing strategies. Therefore, this paper focuses on DBMS fuzzing and provides
a comprehensive review and comparison of the methods in this field. We first
introduce the fundamental concepts. Then, we systematically define a general
fuzzing procedure and decompose and categorize existing methods. Furthermore,
we classify existing methods from the testing objective perspective, covering
various components in DBMSs. For representative works, more detailed
descriptions are provided to analyze their strengths and limitations. To
objectively evaluate the performance of each method, we present an open-source
DBMS fuzzing toolkit, OpenDBFuzz. Based on this toolkit, we conduct a detailed
experimental comparative analysis of existing methods and finally discuss
future research directions.


  Discovering the governing laws underpinning physical and chemical phenomena
is a key step towards understanding and ultimately controlling systems in
science and engineering. We introduce Discovery of Dynamical Systems via Moving
Horizon Optimization (DySMHO), a scalable machine learning framework for
identifying governing laws in the form of differential equations from
large-scale noisy experimental data sets. DySMHO consists of a novel moving
horizon dynamic optimization strategy that sequentially learns the underlying
governing equations from a large dictionary of basis functions. The sequential
nature of DySMHO allows leveraging statistical arguments for eliminating
irrelevant basis functions, avoiding overfitting to recover accurate and
parsimonious forms of the governing equations. Canonical nonlinear dynamical
system examples are used to demonstrate that DySMHO can accurately recover the
governing laws, is robust to high levels of measurement noise and that it can
handle challenges such as multiple time scale dynamics.


  Evolution is the principal theoretical framework in Pacific Island
archaeology. Progressive cultural evolutionary stages, particularly the
chiefdom, provided the earliest framework. These ideas were increasingly linked
to islands as relatively isolated laboratories of cultural evolution and
diversification, albeit their populations phylogenetically linked in a series
of ancestral and descendant societies. With more sophisticated environmental
data, much research has investigated cultural adaptations and their homologous
or analogous origins. Most recently, Darwinian mechanisms of transmission,
selection, and drift comprise an important approach. The history of evolution
in Pacific archaeology suggests it will continue as a useful theoretical
framework, perhaps more so than in other world regions.


  For the first time, the development of the nonlinear geometrically exact
governing equations and corresponding boundary conditions of hanging
cantilevered flexible pipes conveying fluid in the framework of the quaternion
system is undertaken. Additionally, the linear model is derived from the
nonlinear one for the stability analysis. The linear and nonlinear mathematical
formulations based on the geometrically exact rotation-based model are also
extracted from the current model. The obtained integro-partial
differential-algebraic equations are converted to a set of ordinary
differential algebraic equations via the Galerkin discretization technique, and
the resulting equations are numerically solved to determine the self-excited
oscillation behavior of the system in the post-flutter region. The critical
flow velocities, time traces, bifurcation diagrams, phase planes, and deformed
configurations are compared with those reported based on the geometrically
exact rotation-based model. The comparative studies divulge that the present
model can successfully capture the stability and dynamic characteristics of the
system. An interesting feature of the current ordinary differential-algebraic
equations is that their coefficients are time-independent, unlike those of
geometrically exact rotation-based equations in the Galerkin form. The results
show this feature leads to a remarkable decrease in the computational cost,
although the number of equations increases and the nonlinearity becomes
stronger. The challenging issues with the numerical solution utilized in this
study are also discussed.


  In a series of papers, van Geemen and Top have defined a family of surfaces
$S_z$ indexed by a nonzero integer parameter $z$, and a compatible family of
3-dimensional Galois representations over $\Q(i)$ attached to each surface. In
this note we use recent advancements in potential automorphy and automorphy
lifting to show that these compatible families are potentially automophic for
all values of $z$, and hence that their L-functions have analytic continuation
and a functional equation.


  Loop quantum cosmology allows to replace the original singularity by a
quantum bounce followed by a phase of fast expansion called super-inflation. In
this paper, we use a simple analytic description of super-inflation using the
equation of state of a fluid. We then derive the power spectrum of tensor
perturbations produced. The effects on the B-mode polarization of the
cosmological background radiation are discussed. For a large region of phase
space, the spectrum should be distinguishable from the standard inflationary
prediction for future observations.


  An increasing sequence of integers is said to be universal for knots and
links if every knot and link has a projection to the sphere such that the
number of edges of each complementary face of the projection comes from the
given sequence. This paper is an investigation into which sequences, either
finite or infinite, are universal. We also consider how to minimize the number
of odd-sided faces for projections of knots and links with n components.


  In the laser excitation of ultracold atoms to Rydberg states, we observe a
dramatic suppression caused by van der Waals interactions. This behavior is
interpreted as a local excitation blockade: Rydberg atoms strongly inhibit
excitation of their neighbors. We measure suppression, relative to isolated
atom excitation, by up to a factor of 6.4. The dependence of this suppression
on both laser irradiance and atomic density are in good agreement with a
mean-field model. These results are an important step towards using ultracold
Rydberg atoms in quantum information processing.


  Non-randomized treatment effect models are widely used for the assessment of
treatment effects in various fields and in particular social science
disciplines like political science, psychometry, psychology. More specifically,
these are situations where treatment is assigned to an individual based on some
of their characteristics (e.g. scholarship is allocated based on merit or
antihypertensive treatments are allocated based on blood pressure level)
instead of being allocated randomly, as is the case, for example, in randomized
clinical trials. Popular methods that have been largely employed till date for
estimation of such treatment effects suffer from slow rates of convergence
(i.e. slower than $\sqrt{n}$). In this paper, we present a new model coined
SCENTS: Score Explained Non-Randomized Treatment Systems, and a corresponding
method that allows estimation of the treatment effect at $\sqrt{n}$ rate in the
presence of fairly general forms of confoundedness, when the `score' variable
on whose basis treatment is assigned can be explained via certain feature
measurements of the individuals under study. We show that our estimator is
asymptotically normal in general and semi-parametrically efficient under normal
errors. We further extend our analysis to high dimensional covariates and
propose a $\sqrt n$ consistent and asymptotically normal estimator based on a
de-biasing procedure. Our analysis for the high dimensional incarnation can be
readily extended to analyze partial linear models in the presence of noisy
variables corresponding to the non-linear part of the model, where the noise
can be correlated with the variables corresponding to the linear part. We
analyze two real datasets via our method and compare our results with those
obtained by using previous approaches. We conclude this paper with a discussion
on some possible extensions of our approach.


  In old, dense stellar systems collisions of white dwarfs are a rather
frequent phenomenon. Here we present the results of a comprehensive set of
Smoothed Particle Hydrodynamics simulations of close encounters of white dwarfs
aimed to explore the outcome of the interaction and the nature of the final
remnants for different initial conditions. Depending on the initial conditions
and the white dwarf masses, three different outcomes are possible.
Specifically, the outcome of the interaction can be either a direct or a
lateral collision or the interaction can result in the formation of an
eccentric binary system. In those cases in which a collision occurs, the
infalling material is compressed and heated such that the physical conditions
for a detonation may be reached during the most violent phases of the merger.
While we find that detonations occur in a significant number of our
simulations, in some of them the temperature increase in the shocked region
rapidly lifts degeneracy, leading to the quenching of the burning. We thus
characterize under which circumstances a detonation is likely to occur as a
result of the impact of the disrupted star on the surface of the more massive
white dwarf. Finally, we also study which interactions result in bound systems,
and in which ones the more massive white dwarf is also disrupted as a
consequence of the dynamical interaction. The sizable number of simulations
performed in this work allows to find how the outcome of the interaction
depends on the distance at closest approach, and on the masses of the colliding
white dwarfs, and which is the chemical pattern of the nuclearly processed
material. Finally, we also discuss the influence of the masses and core
chemical compositions of the interacting white dwarfs and the different kinds
of impact in the properties of the remnants.


  Rules are widely used in Fintech institutions to make fraud prevention
decisions, since rules are highly interpretable thanks to their intuitive
if-then structure. In practice, a two-stage framework of fraud prevention
decision rule set mining is usually employed in large Fintech institutions;
Stage 1 generates a potentially large pool of rules and Stage 2 aims to produce
a refined rule subset according to some criteria (typically based on precision
and recall). This paper focuses on improving the flexibility and efficacy of
this two-stage framework, and is concerned with finding high-quality rule
subsets in a bi-objective space (such as precision and recall). To this end, we
first introduce a novel algorithm called SpectralRules that directly generates
a compact pool of rules in Stage 1 with high diversity. We empirically find
such diversity improves the quality of the final rule subset. In addition, we
introduce an intermediate stage between Stage 1 and 2 that adopts the concept
of Pareto optimality and aims to find a set of non-dominated rule subsets,
which constitutes a Pareto front. This intermediate stage greatly simplifies
the selection criteria and increases the flexibility of Stage 2. For this
intermediate stage, we propose a heuristic-based framework called PORS and we
identify that the core of PORS is the problem of solution selection on the
front (SSF). We provide a systematic categorization of the SSF problem and a
thorough empirical evaluation of various SSF methods on both public and
proprietary datasets. On two real application scenarios within Alipay, we
demonstrate the advantages of our proposed methodology over existing work.


  We report results of the analysis of the spontaneous symmetry breaking (SSB)
in the basic (actually, simplest) model which is capable to produce the SSB
phenomenology in the one-dimensional setting. It is based on the
Gross-Pitaevskii - nonlinear Schroedinger equation with the cubic
self-attractive term and a double-well-potential built as an infinitely deep
potential box split by a narrow (delta-functional) barrier. The barrier's
strength, epsilon, is the single free parameter of the scaled form of the
model. It may be implemented in atomic Bose-Einstein condensates and nonlinear
optics. The SSB bifurcation of the symmetric ground state (GS) is predicted
analytically in two limit cases, viz., for deep or weak splitting of the
potential box by the barrier. For the generic case, a variational approximation
(VA) is elaborated. The analytical findings are presented along with systematic
numerical results. Stability of stationary states is studied through the
calculation of eigenvalues for small perturbations, and by means of direct
simulations. The GS always undergoes the SSB bifurcation of the supercritical
type, as predicted by the VA at moderate values of epsilon, although the VA
fails at small epsilon, due to inapplicability of the underlying ansatz in that
case. However, the latter case is correctly treated by the approximation based
on a soliton ansatz. On top of the GS, the first and second excited states are
studied too. The antisymmetric mode (the first excited state) is destabilized
at a critical value of its norm. The second excited state undergoes the SSB
bifurcation, like the GS, but, unlike it, the bifurcation produces an unstable
asymmetric mode. All unstable modes tend to spontaneously reshape into the
asymmetric GS.


  In this concluding talk, the advances in the Flavour Problem studies are
discussed, following the structure of the presentations in the Conference. The
subjects touched are organized as follows: Baryons, K-physics, Charm and Beauty
production, Charm and Beauty decays, B-Mixing and CP-Violation, Heavy
Quarkonium.


  Contact discovery allows new users of a messaging service to find existing
contacts that already use that service. Existing users are similarly informed
of new users that join. This creates a privacy issue: anyone already on the
service that has your number on their contact list gets notified that you
joined. Even if you don't know that person, or if it is an ex or former
colleague that you long parted with and whose contact details you deleted long
ago. To solve this, we propose a mutual contact discovery protocol, that only
allow users to discover each other when both are (still) in each other's
contact list. Mutual contact discovery has the additional advantage that it can
be implemented in a more privacy friendly fashion (e.g. protecting the social
graph from the server) than traditional, one-sided contact discovery, without
necessarily relying on trusted hardware.


  The aim of this work is to study the controllability of the Schr\"odinger
equation \begin{equation}\label{eq_abstract} i\partial_t u(t)=-\Delta
u(t)~~~~~\text{ on }\Omega(t) \tag{$\ast$} \end{equation} with Dirichlet
boundary conditions, where $\Omega(t)\subset\mathbb{R}^N$ is a time-varying
domain. We prove the global approximate controllability of \eqref{eq_abstract}
in $L^2(\Omega)$, via an adiabatic deformation $\Omega(t)\subset\mathbb{R}$
($t\in[0,T]$) such that $\Omega(0)=\Omega(T)=\Omega$. This control is strongly
based on the Hamiltonian structure of \eqref{eq_abstract} provided by [18],
which enables the use of adiabatic motions. We also discuss several explicit
interesting controls that we perform in the specific framework of rectangular
domains.


  We introduce a new obstruction to lifting smooth proper varieties in
characteristic $p>0$ to characteristic $0$. It is based on Grothendieck's
specialization homomorphism and the resulting discrete finiteness properties of
\'etale fundamental groups.


  The upper bound on the value of the surface gravity, g_s, for neutron stars
with equations of state respecting v_sound <= c, is derived. This bound is
inversely proportional to the maximum allowable mass M_max, and it reads g_s <=
1.411 x 10^15 (M_sun/M_max) cm/s^2. It implies an absolute upper bound 7.4 x
10^14 cm/s^2 if one uses the 2sigma lower bound on the neutron mass measured
recently in 4U1700-37, 1.9 M_sun. A correlation between g_s and the compactness
parameter 2GM/Rc^2 for baryonic stars is analyzed. The properties of g_s of
strange quark stars and its upper bounds are discussed using the scaling
properties of the strange-star models.


  Large-scale pretrained foundation models have been an emerging paradigm for
building artificial intelligence (AI) systems, which can be quickly adapted to
a wide range of downstream tasks. This paper presents mPLUG, a new
vision-language foundation model for both cross-modal understanding and
generation. Most existing pre-trained models suffer from the problems of low
computational efficiency and information asymmetry brought by the long visual
sequence in cross-modal alignment. To address these problems, mPLUG introduces
an effective and efficient vision-language architecture with novel cross-modal
skip-connections, which creates inter-layer shortcuts that skip a certain
number of layers for time-consuming full self-attention on the vision side.
mPLUG is pre-trained end-to-end on large-scale image-text pairs with both
discriminative and generative objectives. It achieves state-of-the-art results
on a wide range of vision-language downstream tasks, such as image captioning,
image-text retrieval, visual grounding and visual question answering. mPLUG
also demonstrates strong zero-shot transferability when directly transferred to
multiple video-language tasks.


  Intent detection is a crucial task in any Natural Language Understanding
(NLU) system and forms the foundation of a task-oriented dialogue system. To
build high-quality real-world conversational solutions for edge devices, there
is a need for deploying intent detection model on device. This necessitates a
light-weight, fast, and accurate model that can perform efficiently in a
resource-constrained environment. To this end, we propose LIDSNet, a novel
lightweight on-device intent detection model, which accurately predicts the
message intent by utilizing a Deep Siamese Network for learning better sentence
representations. We use character-level features to enrich the sentence-level
representations and empirically demonstrate the advantage of transfer learning
by utilizing pre-trained embeddings. Furthermore, to investigate the efficacy
of the modules in our architecture, we conduct an ablation study and arrive at
our optimal model. Experimental results prove that LIDSNet achieves
state-of-the-art competitive accuracy of 98.00% and 95.97% on SNIPS and ATIS
public datasets respectively, with under 0.59M parameters. We further benchmark
LIDSNet against fine-tuned BERTs and show that our model is at least 41x
lighter and 30x faster during inference than MobileBERT on Samsung Galaxy S20
device, justifying its efficiency on resource-constrained edge devices.


  We address the puzzling weak-coupling perturbative behavior of graphene
interaction effects as manifested experimentally, in spite of the effective
fine structure constant being large, by calculating the effect of Coulomb
interactions on the quasiparticle properties to next-to-leading order in the
random phase approximation (RPA). The focus of our work is graphene suspended
in vacuum, where electron-electron interactions are strong and the system is
manifestly in a nonperturbative regime. We report results for the quasiparticle
residue and the Fermi velocity renormalization at low carrier density. The
smallness of the next-to-leading order corrections that we obtain demonstrates
that the RPA theory converges rapidly and thus, in contrast to the usual
perturbative expansion in the bare coupling constant, constitutes a
quantitatively predictive theory of graphene many-body physics for any coupling
strength.


  We focus on the dominant poles of the transfer function of a descriptor
system. The transfer function typically exhibits large norm at and near the
imaginary parts of the dominant poles. Consequently, the dominant poles provide
information about the points on the imaginary axis where the ${\mathcal
L}_\infty$ norm of the system is attained, and they are also sometimes useful
to obtain crude reduced-order models. For a large-scale descriptor system, we
introduce a subspace framework to estimate a prescribed number of dominant
poles. At every iteration, the large-scale system is projected into a small
system, whose dominant poles can be computed at ease. Then the projection
spaces are expanded so that the projected system after subspace expansion
interpolates the large-scale system at the computed dominant poles. We prove an
at-least-quadratic-convergence result for the framework, and provide numerical
results confirming this. On real benchmark examples, the proposed framework
appears to be more reliable than SAMDP [IEEE Trans. Power Syst. 21, 1471-1483,
2006], one of the widely used algorithms due to Rommes and Martins for the
estimation of the dominant poles.


  A Martian semiannual oscillation (SAO), similar to that in the Earth's
tropical stratosphere, is evident in the Mars Analysis Correction Data
Assimilation reanalysis dataset (MACDA) version 1.0, not only in the tropics,
but also extending to higher latitudes. Unlike on Earth, the Martian SAO is
found not always to reverse its zonal wind direction, but only manifests itself
as a deceleration of the dominant wind at certain pressure levels and
latitudes. Singular System Analysis (SSA) is further applied on the zonal-mean
zonal wind in different latitude bands to reveal the characteristics of SAO
phenomena at different latitudes. The second pair of principal components (PCs)
is usually dominated by a SAO signal, though the SAO signal can be strong
enough to manifest itself also in the first pair of PCs. An analysis of terms
in the Transformed Eulerian Mean equation (TEM) is applied in the tropics to
further elucidate the forcing processes driving the tendency of the zonal-mean
zonal wind. The zonal-mean meridional advection is found to correlate strongly
with the observed oscillations of zonal-mean zonal wind, and supplies the
majority of the westward (retrograde) forcing in the SAO cycle. The forcing due
to various non-zonal waves supplies forcing to the zonal-mean zonal wind that
is nearly the opposite of the forcing due to meridional advection above ~3 Pa
altitude, but it also partly supports the SAO between 40 Pa and 3 Pa. Some
distinctive features occurring during the period of the Mars year (MY) 25
global-scale dust storm (GDS) are also notable in our diagnostic results with
substantially stronger values of eastward and westward momentum in the second
half of MY 25 and stronger forcing due to vertical advection, transient waves
and thermal tides.


  Filters are key devices in optical systems and are usually applied to signal
suppression or selection based on their amplitude frequency responses.
Different from amplitude filtering, an all-pass filter (APF) is a unique type
of filter that exhibits a uniform amplitude and variable phase in the frequency
response. Traditionally, an APF is designed to be ideal and lossless, which is
impossible in practice. Here we demonstrate a method of realizing an APF even
when transmission loss exists, and a possible structure for realizing the lossy
APF is proposed. The method indicates that a lossy APF can be realized by
introducing self-compensation of loss to the structure of an ideal single-stage
APF, and an APF based on silicon-on-insulator (SOI) foundry is fabricated and
demonstrated. The method of self-compensation of loss can also be used to
realize APFs in the electrical domain. We anticipate that our work will inspire
realizations of more APF-related devices that once seemed impossible in
practice.


  The discovery of the present accelerated expansion of space changed
everything regarding cosmology and life's ultimate prospects. Both the
optimistic scenarios of an ever (but decelerated) expanding universe and of a
collapsing universe seem to be no longer available. The final future looks
deadly dark. However, the fate of the universe and intelligence depends
crucially on the nature of the still mysterious dark energy which drives the
accelerated expansion. Depending on its - perhaps time-dependent - equation of
state, there is a confusing number of different models now, popularly called
Big Rip, Big Whimper, Big Decay, Big Crunch, Big Brunch, Big Splat, etc. This
paper briefly reviews possibilities and problems. It also argues that even if
our universe is finally doomed, perhaps that doesn't matter ultimately because
there might be some kind of eternal recurrence. - Key words: Cosmology,
Universe, Dark Energy, Cosmological Constant, Quintessence, Phantom Energy,
Inflation, Quantum Gravity, Far Future, Life, Intelligence


  We construct a family of compact almost Calabi--Yau manifolds of complex
dimension 3 and therein a corresponding family of compact special Lagrangians
with one-point singularities modelled upon that T^2-cone constructed by
Harvey--Lawson and characterized by Haskins as a stable T^2-cone in the
terminology by Joyce.


  An analytically solvable model is proposed exhibiting 1/f spectrum in any
desirably wide range of frequency (but excluding the point f=0). The model
consists of pulses whose recurrence times obey an autoregressive process with
very small damping.


  Delay Deviation Exceedance (DDE) and Differential Skew Exceedance (DSE)
measures are proposed to quantify delay uncertainty in single-ended and
differential PCB interconnects arising from Fiber Weave Effect (FWE). DDE and
DSE are constructed with 3D EM analysis of traces over inhomogeneous dielectric
with glass fiber bundles in resin. Measurements or 3D EM models for FWE are
usually used for observations of delay or impedance dependency on position of
traces over fiber bundles with the purpose to find the worst case scenario.
This paper turns the results of 3D EM analysis into probabilistic measures of
possible delay or skew uncertainty - probability to have delay deviation in
single-ended interconnects over allowed limit (DDE measure) or to have skew
over allowed limit in differential interconnects (DSE measure). The introduced
measures allow formalizing the laminate selection process for parallel as well
as for serial PCB interconnects.


  We experimentally study the transport properties of silicon quantum dots
(QDs) fabricated from a highly doped n-type silicon-on-insulator wafer. Low
noise electrical measurements using a low temperature complementary
metal-oxide-semiconductor (LTCMOS) amplifier are performed at 4.2 K in liquid
helium. Two series of Coulomb peaks are observed: long-period oscillations and
fine structures, and both of them show clear source drain voltage dependence.
We also observe two series of Coulomb diamonds having different periodicity.
The obtained experimental results are well reproduced by a master equation
analysis using a model of double QDs coupled in parallel.


  In this paper, we consider the problem of minimizing the sum of two convex
functions subject to linear linking constraints. The classical alternating
direction type methods usually assume that the two convex functions have
relatively easy proximal mappings. However, many problems arising from
statistics, image processing and other fields have the structure that while one
of the two functions has easy proximal mapping, the other function is smoothly
convex but does not have an easy proximal mapping. Therefore, the classical
alternating direction methods cannot be applied. To deal with the difficulty,
we propose in this paper an alternating direction method based on
extragradients. Under the assumption that the smooth function has a Lipschitz
continuous gradient, we prove that the proposed method returns an
$\epsilon$-optimal solution within $O(1/\epsilon)$ iterations. We apply the
proposed method to solve a new statistical model called fused logistic
regression. Our numerical experiments show that the proposed method performs
very well when solving the test problems. We also test the performance of the
proposed method through solving the lasso problem arising from statistics and
compare the result with several existing efficient solvers for this problem;
the results are very encouraging indeed.


  We study the real rank of points with respect to a real variety $X$. This is
a generalization of various tensor ranks, where $X$ is in a specific family of
real varieties like Veronese or Segre varieties. The maximal real rank can be
bounded in terms of the codimension of $X$ only. We show constructively that
there exist varieties $X$ for which this bound is tight. The same varieties
provide examples where a previous bound of Blekherman-Teitler on the maximal
$X$-rank is tight. We also give examples of varieties $X$ for which the gap
between maximal complex and the maximal real rank is arbitrarily large. To
facilitate our constructions we prove a conjecture of Reznick on the maximal
real symmetric rank of symmetric bivariate tensors. Finally we study the
geometry of the set of points of maximal real rank in the case of real plane
curves.


  Editing of portrait images is a very popular and important research topic
with a large variety of applications. For ease of use, control should be
provided via a semantically meaningful parameterization that is akin to
computer animation controls. The vast majority of existing techniques do not
provide such intuitive and fine-grained control, or only enable coarse editing
of a single isolated control parameter. Very recently, high-quality
semantically controlled editing has been demonstrated, however only on
synthetically created StyleGAN images. We present the first approach for
embedding real portrait images in the latent space of StyleGAN, which allows
for intuitive editing of the head pose, facial expression, and scene
illumination in the image. Semantic editing in parameter space is achieved
based on StyleRig, a pretrained neural network that maps the control space of a
3D morphable face model to the latent space of the GAN. We design a novel
hierarchical non-linear optimization problem to obtain the embedding. An
identity preservation energy term allows spatially coherent edits while
maintaining facial integrity. Our approach runs at interactive frame rates and
thus allows the user to explore the space of possible edits. We evaluate our
approach on a wide set of portrait photos, compare it to the current state of
the art, and validate the effectiveness of its components in an ablation study.


  Conversational practice, while crucial for all language learners, can be
challenging to get enough of and very expensive. Chatbots are computer programs
developed to engage in conversations with humans. They are designed as software
avatars with limited, but growing conversational capability. The most natural
and potentially powerful application of chatbots is in line with their
fundamental nature - language practice. However, their role and outcomes within
(in)formal language learning are currently tangential at best. Existing
research in the area has generally focused on chatbots' comprehensibility and
the motivation they inspire in their users. In this paper, we provide an
overview of the chatbots for learning languages, critically analyze existing
approaches, and discuss the major challenges for future work.


  In the context of modeling biological systems, it is of interest to generate
ideals of points with a unique reduced Groebner basis, and the first main goal
of this paper is to identify classes of ideals in polynomial rings which share
this property. Moreover, we provide methodologies for constructing such ideals.
We then relax the condition of uniqueness. The second and most relevant topic
discussed here is to consider and identify pairs of ideals with the same number
of reduced Groebner bases, that is, with the same cardinality of their
associated Groebner fan.


  Despite the remarkable achievements of language models (LMs) across a broad
spectrum of tasks, their propensity for generating toxic outputs remains a
prevalent concern. Current solutions involving fine-tuning or auxiliary models
usually require extensive memory and computational resources, rendering them
less practical for deployment in large language models (LLMs). In this paper,
we propose DeStein, a novel method that detoxififies LMs by altering their
internal representations in the activation space with lower resource and time
cost. Specifically, we leverage self-induced steering pairs to identify
detoxification vectors through arithmetic operations in the activation space.
During inference, detoxification is achieved by blending the detoxification
vectors with the original representations. Empirical results demonstrate that
our method significantly outperforms previous state-of-the-art approaches on
popular detoxification metrics, while also maintaining satisfactory generation
quality and diversity. Furthermore, we extend our method to multiple LLMs,
demonstrating its practicality and scalability. We open-source our method at
https://github.com/LizLizLi/DeStein . Warning: Some example model outputs
contain highly offensive or disturbing text.


  This paper focuses on developing a more effective method of hierarchical
propagation for semi-supervised Video Object Segmentation (VOS). Based on
vision transformers, the recently-developed Associating Objects with
Transformers (AOT) approach introduces hierarchical propagation into VOS and
has shown promising results. The hierarchical propagation can gradually
propagate information from past frames to the current frame and transfer the
current frame feature from object-agnostic to object-specific. However, the
increase of object-specific information will inevitably lead to the loss of
object-agnostic visual information in deep propagation layers. To solve such a
problem and further facilitate the learning of visual embeddings, this paper
proposes a Decoupling Features in Hierarchical Propagation (DeAOT) approach.
Firstly, DeAOT decouples the hierarchical propagation of object-agnostic and
object-specific embeddings by handling them in two independent branches.
Secondly, to compensate for the additional computation from dual-branch
propagation, we propose an efficient module for constructing hierarchical
propagation, i.e., Gated Propagation Module, which is carefully designed with
single-head attention. Extensive experiments show that DeAOT significantly
outperforms AOT in both accuracy and efficiency. On YouTube-VOS, DeAOT can
achieve 86.0% at 22.4fps and 82.0% at 53.4fps. Without test-time augmentations,
we achieve new state-of-the-art performance on four benchmarks, i.e.,
YouTube-VOS (86.2%), DAVIS 2017 (86.2%), DAVIS 2016 (92.9%), and VOT 2020
(0.622). Project page: https://github.com/z-x-yang/AOT.


  Question answering (QA) models are well-known to exploit data bias, e.g., the
language prior in visual QA and the position bias in reading comprehension.
Recent debiasing methods achieve good out-of-distribution (OOD)
generalizability with a considerable sacrifice of the in-distribution (ID)
performance. Therefore, they are only applicable in domains where the test
distribution is known in advance. In this paper, we present a novel debiasing
method called Introspective Distillation (IntroD) to make the best of both
worlds for QA. Our key technical contribution is to blend the inductive bias of
OOD and ID by introspecting whether a training sample fits in the factual ID
world or the counterfactual OOD one. Experiments on visual QA datasets VQA v2,
VQA-CP, and reading comprehension dataset SQuAD demonstrate that our proposed
IntroD maintains the competitive OOD performance compared to other debiasing
methods, while sacrificing little or even achieving better ID performance
compared to the non-debiasing ones.


  A semi-classical non-Hamiltonian model of a spontaneous collapse of unstable
quantum system is given. The time evolution of the system becomes
non-Hamiltonian at random instants of transition of pure states to reduced
ones, given by a contraction C. The counting trajectories are assumed to
satisfy the Poisson law. A unitary dilation of the concractive stochastic
dynamics is found. In particular, in the limit of frequent detection
corresponding to the large number limit we obtain the Ito-Schroedinger
stochastic unitary evolution for the pure state of unstable quantum system
providing a new stochastic version of the quantum Zeno effect.


  The bremsstrahlung flux-averaged cross-sections $\langle{\sigma(E_{\rm{\gamma
max}})}\rangle$ for the $^{181}\rm{Ta}(\gamma,\textit{x}n; \textit{x} = 1 \div
8)^{181-\textit{x}}\rm{Ta}$ photoneutron reactions have been measured at
end-point bremsstrahlung energies ranging from 80 MeV to 95 MeV. The
measurements were performed with the beam from the NSC KIPT electron linear
accelerator LUE-40 using the residual $\gamma$-activity method. The theoretical
$\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ values were computed using the
cross-sections $\sigma(E)$ from TALYS1.9 code. A comparison between the
measured cross-sections $\langle{\sigma(E_{\rm{\gamma max}})}\rangle$ and the
theoretical values has demostrated their good agreement for the reactions with
escape of up to 6 neutrons, and substantial differences for the
$(\gamma,7\rm{n})$ and $(\gamma,8\rm{n})$ reactions. Isomeric ratios of the
average cross-sections $d(E_{\rm{\gamma max}})$ have been found for the
$^{181}\rm{Ta}(\gamma,3n)^{178g,m}\rm{Ta}$ reaction products. The results have
been compared with the literature data and the computations based on TALYS1.9
code.


  We prove a general principle satisfied by weakly precompact sets of
Lipschitz-free spaces. By this principle, certain infinite dimensional
phenomena in Lipschitz-free spaces over general metric spaces may be reduced to
the same phenomena in free spaces over their compact subsets. As easy
consequences we derive several new and some known results. The main new results
are: $\mathcal F(X)$ is weakly sequentially complete for every superreflexive
Banach space $X$, and $\mathcal F(M)$ has the Schur property and the
approximation property for every scattered complete metric space $M$.


  A new and powerful probe of the origin and evolution of structures in the
Universe has emerged and been actively developed over the last decade. In the
coming decade, non-Gaussianity, i.e., the study of non-Gaussian contributions
to the correlations of cosmological fluctuations, will become an important
probe of both the early and the late Universe. Specifically, it will play a
leading role in furthering our understanding of two fundamental aspects of
cosmology and astrophysics: (i) the physics of the very early universe that
created the primordial seeds for large-scale structures, and (ii) the
subsequent growth of structures via gravitational instability and gas physics
at later times. To date, observations of fluctuations in the Cosmic Microwave
Background (CMB) and the Large-Scale Structure of the Universe (LSS) have
focused largely on the Gaussian contribution as measured by the two-point
correlations (or the power spectrum) of density fluctuations. However, an even
greater amount of information is contained in non-Gaussianity and a large
discovery space therefore still remains to be explored. Many observational
probes can be used to measure non-Gaussianity, including CMB, LSS,
gravitational lensing, Lyman-alpha forest, 21-cm fluctuations, and the
abundance of rare objects such as clusters of galaxies and high-redshift
galaxies. Not only does the study of non-Gaussianity maximize the science
return from a plethora of present and future cosmological experiments and
observations, but it also carries great potential for important discoveries in
the coming decade.


  We calculate the additive structure (together with the grading) of the
Hochschild homology and cohomology and the cyclic homology of preprojective
algebras of types ADE.


  Recent astronomical observations of SNIa, CMB, as well as BAO in the Sloan
Digital Sky Survey, suggest that the current Universe has entered a stage of an
accelerated expansion with the transition redshift at $z \simeq 0.5$. While the
simplest candidates to explain this fact is cosmological constant/vacuum
energy, there exists a serious problem of coincidence. In theoretical cosmology
we can find many possible approaches alleviating this problem by applying new
physics or other conception of dark energy. We consider state of art candidates
for the description of accelerating Universe in the framework of the Bayesian
model selection. We point out advantages as well as troubles of this approach.
We find that the combination of four data bases gives a stringent posterior
probability of the $\Lambda$CDM model which is 74%. This fact is a quantitative
exemplification of a turmoil in modern cosmology over the $\Lambda$ problem.


  In last few decades large technology development raised various new needs.
Financial sector has also no exception. People are approaching all over the
world to fulfill there dreams. Any sector needs to understand changing need of
customer. In order to satisfy financial need for customer banks are taking help
of new technology such as internet. Only problem remain is of security. The aim
of this work is to provide a secure environment in terms of security for
transaction by various ways. In order to improve security we are making use of
"Steganography" technique in the way never used before. Task of enhancing
security include construction of formula for both data encryption and also for
hiding pattern. Server should not process any fake request hence concept of
custom "Session id" and "Request id" is introduced. Implementation of such a
security constraints in banking sector not only help to serve customer in
better way but also make customer confident and satisfy.


  An adjustable algorithm of exclusion of conditional equations with excessive
residuals is proposed. The criteria applied in the algorithm use variable
exclusion limits which decrease as the number of equations goes down. The
algorithm is easy to use, it possesses rapid convergence, minimal subjectivity,
and high degree of generality.


  In this paper we consider reinsurance or risk sharing from a macroeconomic
point of view. Our aim is to find socially optimal reinsurance treaties. In our
setting we assume that there are $n$ insurance companies each bearing a certain
risk and one representative reinsurer. The optimization problem is to minimize
the sum of all capital requirements of the insurers where we assume that all
insurance companies use a form of Range-Value-at-Risk. We show that in case all
insurers use Value-at-Risk and the reinsurer's premium principle satisfies
monotonicity, then layer reinsurance treaties are socially optimal. For this
result we do not need any dependence structure between the risks. In the
general setting with Range-Value-at-Risk we obtain again the optimality of
layer reinsurance treaties under further assumptions, in particular under the
assumption that the individual risks are positively dependent through the
stochastic ordering. At the end, we discuss the difference between socially
optimal reinsurance treaties and individually optimal ones by looking at a
number of special cases.


  Recurrent neural networks (RNNs) have represented for years the state of the
art in neural machine translation. Recently, new architectures have been
proposed, which can leverage parallel computation on GPUs better than classical
RNNs. Faster training and inference combined with different
sequence-to-sequence modeling also lead to performance improvements. While the
new models completely depart from the original recurrent architecture, we
decided to investigate how to make RNNs more efficient. In this work, we
propose a new recurrent NMT architecture, called Simple Recurrent NMT, built on
a class of fast and weakly-recurrent units that use layer normalization and
multiple attentions. Our experiments on the WMT14 English-to-German and WMT16
English-Romanian benchmarks show that our model represents a valid alternative
to LSTMs, as it can achieve better results at a significantly lower
computational cost.


  Wikipedia is widely used for finding general information about a wide variety
of topics. Its vocation is not to provide local information. For example, it
provides plot, cast, and production information about a given movie, but not
showing times in your local movie theatre. Here we describe how we can connect
local information to Wikipedia, without altering its content. The case study we
present involves finding local scientific experts. Using a third-party
taxonomy, independent from Wikipedia's category hierarchy, we index information
connected to our local experts, present in their activity reports, and we
re-index Wikipedia content using the same taxonomy. The connections between
Wikipedia pages and local expert reports are stored in a relational database,
accessible through as public SPARQL endpoint. A Wikipedia gadget (or plugin)
activated by the interested user, accesses the endpoint as each Wikipedia page
is accessed. An additional tab on the Wikipedia page allows the user to open up
a list of teams of local experts associated with the subject matter in the
Wikipedia page. The technique, though presented here as a way to identify local
experts, is generic, in that any third party taxonomy, can be used in this to
connect Wikipedia to any non-Wikipedia data source.


  We examine the coexistence of spherical and $\gamma$-unstable deformed
nuclear shapes, described by an SO(5)-invariant Bohr Hamiltonian, along the
critical-line. Calculations are performed in the Algebraic Collective Model by
introducing two separate bases, optimized to accommodate simultaneously
different forms of dynamics. We demonstrate the need to modify the
$\beta$-dependence of the moments of inertia, in order to obtain an adequate
description of such shape-coexistence.


  For the multi-mode Dicke model in a transport setting that exhibits
collective boson transmissions, we construct the equation of motion for the
cumulant generating function. Approximating the exact system of equations at
the level of cumulant generating function and system operators at lowest order,
allows us to recover master equation results of the Full Counting Statistics
for certain parameter regimes at very low cost of computation. The
thermodynamic limit, that is not accessible with the master equation approach,
can be derived analytically for different approximations.


  We have studied the Devonshire-Landau potential underlying the phase
transition sequence of BaTiO3 using the first-principles effective Hamiltonian
of Zhong, Vanderbilt, and Rabe [Phys. Rev. Lett. 73, 1861 (1994)], which has
been very successful in reproducing the phase transitions and the dielectric
and piezoelectric properties of this compound. The configuration space
(determined by the polarization P as order parameter) was explored with the
help of auxiliary electric fields. We show that the typically assumed form of
the potential, a sixth-order expansion in P around the paraelectric cubic
phase, properly accounts for the behavior of the system, but we find a
non-trivial temperature dependence for all the coefficients in the expansion,
including the quadratic one, which is shown to behave non-linearly. Our results
also prove that the sixth-order terms in the free-energy expansion (needed to
account for the first-order character of the transitions and the occurrence of
an orthorhombic phase) emerge from an interaction model that only includes
terms up to fourth order.


  We study aspects of two-dimensional nonlinear sigma models with Wess-Zumino
term corresponding to a nonclosed 3-form, which may arise upon dimensional
reduction in the target space. Our goal in this paper is twofold. In a first
part, we investigate the conditions for consistent gauging of sigma models in
the presence of a nonclosed 3-form. In the Abelian case, we find that the
target of the gauged theory has the structure of a contact Courant algebroid,
twisted by a 3-form and two 2-forms. Gauge invariance constrains the theory to
(small) Dirac structures of the contact Courant algebroid. In the non-Abelian
case, we draw a similar parallel between the gauged sigma model and certain
transitive Courant algebroids and their corresponding Dirac structures. In the
second part of the paper, we study two-dimensional sigma models related to
Jacobi structures. The latter generalise Poisson and contact geometry in the
presence of an additional vector field. We demonstrate that one can construct a
sigma model whose gauge symmetry is controlled by a Jacobi structure, and
moreover we twist the model by a 3-form. This construction is then the analogue
of WZW-Poisson structures for Jacobi manifolds.


  The detection of very-high-energy (VHE) neutrinos ($E_\nu \gtrsim 10$ PeV) is
a challenge that future generations of experiments are being designed and
constructed to address. One promising method relies on using the Earth as a
neutrino target for indirect detection of skimming tau neutrinos interacting
within the Earth and producing tau leptons that are able to escape and decay in
the atmosphere. The tau decay produces upward-moving Extensive Air Showers
(EASs). A space-based or suborbital instrument observing the ground near the
Earth limb can search for the beamed Cherenkov signal produced by the up-going
EAS resulting from the tau-lepton decay. In this paper, we derive the
geometrical constraints for such an observation in general and for the specific
case of the Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) mission
currently under study, focusing on the Cherenkov signal detection. We show
that, using reasonable orbital parameters, POEMMA can achieve full-sky coverage
to search for potential neutrino sources over the length of its mission. We
also show that follow-up of a transient Target-of-Opportunity (ToO), such as a
flaring source, can be achieved within an orbit time scale depending on the
source location on the celestial sphere and its relative position with respect
to the Sun and the Moon.