pinecone/core-2020-05-10-deduplication huggingface dataset:
Optimal construction of k-nearest neighbor graphs for identifying noisy
  clusters

We study clustering algorithms based on neighborhood graphs on a random
sample of data points. The question we ask is how such a graph should be
constructed in order to obtain optimal clustering results. Which type of
neighborhood graph should one choose, mutual k-nearest neighbor or symmetric
k-nearest neighbor? What is the optimal parameter k? In our setting, clusters
are defined as connected components of the t-level set of the underlying
probability distribution. Clusters are said to be identified in the
neighborhood graph if connected components in the graph correspond to the true
underlying clusters. Using techniques from random geometric graph theory, we
prove bounds on the probability that clusters are identified successfully, both
in a noise-free and in a noisy setting. Those bounds lead to several
conclusions. First, k has to be chosen surprisingly high (rather of the order n
than of the order log n) to maximize the probability of cluster identification.
Secondly, the major difference between the mutual and the symmetric k-nearest
neighbor graph occurs when one attempts to detect the most significant cluster
only.Comment: 31 pages, 2 figure
Zonal polynomials via Stanley's coordinates and free cumulants

We study zonal characters which are defined as suitably normalized
coefficients in the expansion of zonal polynomials in terms of power-sum
symmetric functions. We show that the zonal characters, just like the
characters of the symmetric groups, admit a nice combinatorial description in
terms of Stanley's multirectangular coordinates of Young diagrams. We also
study the analogue of Kerov polynomials, namely we express the zonal characters
as polynomials in free cumulants and we give an explicit combinatorial
interpretation of their coefficients. In this way, we prove two recent
conjectures of Lassalle for Jack polynomials in the special case of zonal
polynomials.Comment: 45 pages, second version, important change
Production of doubly strange hypernuclei via {\Xi}- doorways in the
  16O(K-, K+) reaction at 1.8 GeV/c

We examine theoretically production of doubly strange hypernuclei, 16 {\Xi}-C
and 16 {\Lambda}{\Lambda}C, in doublecharge exchange 16O(K-, K+) reactions
using a distorted-wave impulse approximation. The inclusive K+ spectrum at the
incident momentum pK- = 1.8 GeV/c and scattering angle {\theta}lab = 0^{\circ}
is estimated in a one-step mechanism, K-p \to K+{\Xi}- via {\Xi}- doorways
caused by a {\Xi}-p-{\Lambda}{\Lambda} coupling. The calculated spectrum in the
{\Xi}- bound region indicates that the integrated cross sections are on the
order of 7-12 nb/sr for significant 1- excited states with 14C(0+, 2+) \otimes
s{\Lambda}p{\Lambda} configurations in 16 {\Lambda}{\Lambda}C via the doorway
states of the spin-stretched 15N(1/2-, 3/2-) \otimes s{\Xi}- in 16 {\Xi}-C due
to a high momentum transfer q{\Xi}- \approx 400 MeV/c. The {\Xi}- admixture
probabilities of these states are on the order of 5-9%. However, populations of
the 0+ ground state with 14C(0+) \otimes s2{\Lambda} and the 2+ excited state
with 14C(2+) \otimes s2 {\Lambda} are very small. The sensitivity of the
spectrum on the {\Xi}N-{\Lambda}{\Lambda} coupling strength enables us to
extract the nature of {\Xi}N-{\Lambda}{\Lambda} dynamics in nuclei, and the
nuclear (K-, K+) reaction can extend our knowledge of the S = -2 world.Comment: 10 pages, 3 figure
Who's reporting the protests?: converging practices of citizen journalists and two BBC World Service newsrooms, from Iran’s election protests to the Arab uprisings

The 2009 protests in Iran and the 2011 Arab uprisings took place in complex and fast evolving media ecologies. The BBC's Persian and Arabic language services, which reach millions, drew heavily on content created by ordinary citizens to cover events. This paper traces the flow of this content through the news process to examine how collaboration between newsrooms and citizen journalists changed from 2009 to 2011. The article argues that participation in the news process hinges on the congruence between newsroom practices, and the practices of those producing content on the streets. Such congruence requires mutual knowledge of broadcasting requirements. It finds that by 2011 journalists felt more comfortable and effective integrating user-generated content (UGC) into their news output. Importantly, UGC creators appear to have taken on board the broadcaster's editorial requirements, making them savvier content creators
Single-order-parameter description of glass-forming liquids: A
  one-frequency test

Thermo-viscoelastic linear-response functions are calculated from the master
equation describing viscous liquid inherent dynamics. From the imaginary parts
of the frequency-dependent isobaric specific heat, isothermal compressibility,
and isobaric thermal expansion coefficient, we define a "linear dynamic
Prigogine-Defay ratio" with the property that if this quantity is unity atone
frequency, then it is unity at all frequencies. This happens if and only if
there is a single-order-parameter description of the thermo-viscoelastic linear
responses via an order parameter (which may be non-exponential in time).
Generalizations to other cases of thermodynamic control parameters than
temperature and pressure are treated in an Appendix.Comment: Replaces arXiv:cond-mat/040570
New Model of Internet Topology Using k-shell Decomposition

We introduce and use k-shell decomposition to investigate the topology of the
Internet at the AS level. Our analysis separates the Internet into three
sub-components: (a) a nucleus which is a small (~100 nodes) very well connected
globally distributed subgraph; (b) a fractal sub-component that is able to
connect the bulk of the Internet without congesting the nucleus, with self
similar properties and critical exponents; and (c) dendrite-like structures,
usually isolated nodes that are connected to the rest of the network through
the nucleus only. This unique decomposition is robust, and provides insight
into the underlying structure of the Internet and its functional consequences.
Our approach is general and useful also when studying other complex networks.Comment: 4 pages, 4 figure
Searches for Gauge-Mediated Supersymmetry Breaking Topologies in e+e-
  collisions at LEP2

In gauge-mediated supersymmetry (SUSY) breaking (GMSB) models the lightest
supersymmetric particle (LSP) is the gravitino and the phenomenology is driven
by the nature of the next-to-lightest SUSY particle (NLSP) which is either the
lightest neutralino, the stau or mass degenerate sleptons. Since the NLSP decay
length is effectively unconstrained, searches for all possible lifetime and
NLSP topologies predicted by GMSB models in e+e- collisions are performed on
the data sample collected by OPAL at centre-of-mass energies up to 209 GeV at
LEP. Results independent of the NLSP lifetime are presented for all relevant
final states including direct NLSP pair-production and, for the first time,
also NLSP production via cascade decays of heavier SUSY particles. None of the
searches shows evidence for SUSY particle production. Cross-section limits are
presented at the 95% confidence level both for direct NLSP production and for
cascade decays, providing the most general, almost model independent results.
These results are then interpreted in the framework of the minimal GMSB (mGMSB)
model, where large areas of the accessible parameter space are excluded. In the
mGMSB model, the NLSP masses are constrained to be larger than 53.5 GeV/c^2,
87.4 GeV/c^2 and 91.9 GeV/c^2 in the neutralino, stau and slepton co-NLSP
scenarios, respectively. A complete scan on the parameters of the mGMSB model
is performed, constraining the universal SUSY mass scale Lambda from the direct
SUSY particle searches: Lambda > 40, 27, 21, 17, 15 TeV/c^2 for messenger
indices N=1, 2, 3, 4, 5 respectively, for all NLSP lifetimes.Comment: 4 pages, 2 figures. To appear in Proceedings of SUSY06, the 14th
  International Conference on Supersymmetry and the Unification of Fundamental
  Interactions, UC Irvine, California, 12-17 June 200
Study of exclusive two-photon production of W(+)W(-) in pp collisions at
  sqrt(s) = 7 TeV and constraints on anomalous quartic gauge couplings

A search for exclusive or quasi-exclusive W(+)W(-) production by
photon-photon interactions, pp to p(*)W(+)W(-)p(*), at sqrt(s) = 7 TeV is
reported using data collected by the CMS detector with an integrated luminosity
of 5.05 inverse femtobarns. Events are selected by requiring a mu(+/-)e(-/+)
vertex with no additional associated charged tracks and dilepton transverse
momentum pt(mu(+/-)e(-/+)) > 30 GeV. Two events passing all selection
requirements are observed in the data, compared to a standard model expectation
of 2.2 +/- 0.4 signal events with 0.84 +/- 0.15 background. The tail of the
dilepton pt distribution is studied for deviations from the standard model. No
events are observed with pt > 100 GeV. Model-independent upper limits are
computed and compared to predictions involving anomalous quartic gauge
couplings. The limits on the parameters a[W,(0,C)]/Lambda^2 with a dipole form
factor and an energy cutoff Lambda(cutoff) = 500 GeV are of the order of 10E-4.Comment: Updated author list. Previous version: replaced with published
  version; added journal reference and DO
Local supersymmetry without SUSY partners

A gauge theory for a superalgebra that includes an internal gauge (G) and
local Lorentz algebras, and that could describe the low energy particle
phenomenology is constructed. These two symmetries are connected by fermionic
supercharges. The system includes an internal gauge connection 1-form $A$, a
spin-1/2 Dirac spinor $\psi$, the Lorentz connection $\omega$, and the vielbein
$e$. The connection one-form is in the adjoint representation of G, while
$\psi$ is in the fundamental. In contrast to standard supergravity, the metric
is not a fundamental field and is in the center of the superalgebra: it is not
only invariant under the internal gauge group and under Lorentz
transformations, but is also invariant under supersymmetry. The features of
this theory that mark the difference with standard supersymmetry are: A) The
number of fermionic and bosonic states is not necessarily the same; B) There
are no superpartners with equal mass, "bosoninos", sleptons and squarks are
absent; C) Although this supersymmetry originates in a local gauge theory and
gravity is included, there is no gravitino; D) Fermions acquire mass from their
coupling to the background or from self-couplings, while bosons remain
massless. In odd dimensions, the Chern-Simons form provides an action that is
quasi-invariant under the entire superalgebra. In even dimensions, the
Yang-Mills form $ < F *F>$ is the only natural option, and the symmetry breaks
down to [G x SO(1,D-1)]. In 4D, the construction follows the Townsend - Mac
Dowell-Mansouri approach. Due to the absence of osp(4|2)-invariant traces in
four dimensions, the resulting Lagrangian is only invariant under [U(1) x
SO(3,1)], and includes a Nambu--Jona-Lasinio term. In this case, the Lagrangian
depends on a single dimensionful parameter that fixes Newton's constant, the
cosmological constant and the NJL coupling.Comment: 24 pages, no figures. Title changed in journal version to
  "Unconventional supersymmetry and its breaking". Few references added and
  some paragraphs rewritten from v.1. This version includes two appendices that
  are not found in the journal versio
Massively parallel solvers for elliptic PDEs in Numerical Weather- and
  Climate Prediction

The demand for substantial increases in the spatial resolution of global
weather- and climate- prediction models makes it necessary to use numerically
efficient and highly scalable algorithms to solve the equations of large scale
atmospheric fluid dynamics. For stability and efficiency reasons several of the
operational forecasting centres, in particular the Met Office and the ECMWF in
the UK, use semi-implicit semi-Lagrangian time stepping in the dynamical core
of the model. The additional burden with this approach is that a three
dimensional elliptic partial differential equation (PDE) for the pressure
correction has to be solved at every model time step and this often constitutes
a significant proportion of the time spent in the dynamical core. To run within
tight operational time scales the solver has to be parallelised and there seems
to be a (perceived) misconception that elliptic solvers do not scale to large
processor counts and hence implicit time stepping can not be used in very high
resolution global models. After reviewing several methods for solving the
elliptic PDE for the pressure correction and their application in atmospheric
models we demonstrate the performance and very good scalability of Krylov
subspace solvers and multigrid algorithms for a representative model equation
with more than $10^{10}$ unknowns on 65536 cores on HECToR, the UK's national
supercomputer. For this we tested and optimised solvers from two existing
numerical libraries (DUNE and hypre) and implemented both a Conjugate Gradient
solver and a geometric multigrid algorithm based on a tensor-product approach
which exploits the strong vertical anisotropy of the discretised equation. We
study both weak and strong scalability and compare the absolute solution times
for all methods; in contrast to one-level methods the multigrid solver is
robust with respect to parameter variations.Comment: 24 pages, 7 figures, 7 table
The 72-Hour WEBT Microvariability Observation of Blazar S5 0716+714 in
  2009

Context. The international whole earth blazar telescope (WEBT) consortium
planned and carried out three days of intensive micro-variability observations
of S5 0716+714 from February 22, 2009 to February 25, 2009. This object was
chosen due to its bright apparent magnitude range, its high declination, and
its very large duty cycle for micro-variations. Aims. We report here on the
long continuous optical micro-variability light curve of 0716+714 obtained
during the multi-site observing campaign during which the Blazar showed almost
constant variability over a 0.5 magnitude range. The resulting light curve is
presented here for the first time. Observations from participating
observatories were corrected for instrumental differences and combined to
construct the overall smoothed light curve. Methods. Thirty-six observatories
in sixteen countries participated in this continuous monitoring program and
twenty of them submitted data for compilation into a continuous light curve.
The light curve was analyzed using several techniques including Fourier
transform, Wavelet and noise analysis techniques. Those results led us to model
the light curve by attributing the variations to a series of synchrotron
pulses. Results. We have interpreted the observed microvariations in this
extended light curve in terms of a new model consisting of individual
stochastic pulses due to cells in a turbulent jet which are energized by a
passing shock and cool by means of synchrotron emission. We obtained an
excellent fit to the 72-hour light curve with the synchrotron pulse model
Electric/magnetic duality and RG flows in AdS4/CFT3

A large set of relevant deformations of the ABJM field theory on a stack of
M2 branes is captured holographically by D=4 N=8 SO(8)-gauged supergravity,
which has accordingly been applied to study renormalisation group (RG) flows of
the field theory between distinct superconformal phases. Recently, it has been
discovered that this supergravity is not unique, and that a one-parameter
family of gaugings of maximal supergravity exists. The parameter is an angle
that measures the mixture of electric and magnetic vectors that gauge SO(8)
dyonically. We construct and comprehensively characterise all domain walls
between the critical points of the new supergravities with at least SU(3)
invariance, which are expected to be dual to RG flows of new field theories
defined at least at large N. We also construct some walls running off to
infinity in scalar space, which we expect to be dual to Coulomb branch flows of
these field theories.Comment: 36 pages, 12 figures, lots of coffee; v2. references and
  acknowledgements added, a few points clarified; v3. minor change
A Herschel view of IC 1396 A: Unveiling the different sequences of star
  formation

The IC1396A globule in the young cluster Tr37, hosting many young stars and
protostars, is assumed to be a site of triggered star formation. We mapped
IC1396A with Herschel/PACS at 70 and 160 micron. The Herschel maps trace in
great detail the very embedded protostellar objects and the structure of the
cloud. PACS data reveal a previously unknown Class 0 object (IC1396A-PACS-1)
located behind the ionization front. IC1396A-PACS-1 is not detectable with
Spitzer, but shows marginal X-ray emission. The data also allowed to study
three of the Class I intermediate-mass objects within the cloud. We derived
approximate cloud temperatures to study the effect and potential interactions
between the protostars and the cloud. The Class 0 object is associated with the
densest and colder part of IC1396A. Heating in the cloud is dominated by the
winds and radiation of the O6.5 star HD 206267 and, to a lesser extent, by the
effects of the Herbig Ae star V 390 Cep. The surroundings of the Class I and
Class II objects embedded in the cloud also appear warmer than the sourceless
areas, although most of the low-mass objects cannot be individually extracted
due to distance and beam dilution. The observations suggest that at least two
episodes of star formation have occurred in IC1396A. One would have originated
the known, ~1 Myr-old Class I and II objects in the cloud, and a new wave of
star formation would have produced the Class 0 source at the tip of the
brigth-rimmed cloud. From its location and properties, IC1396A-PACS-1 is
consistent with triggering via radiative driven implosion (RDI) induced by HD
206267. The mechanisms behind the formation of the more evolved population of
Class I/II/III objects in the cloud are uncertain. Heating of most of the
remaining cloud by Class I/Class II objects and by HD 206267 itself may
preclude further star formation in the region.Comment: Accepted by A&A, 9 pages, 5 figure
The T7 flavor symmetry in 3-3-1 model with neutral leptons

We construct a 3-3-1 model based on non-Abelian discrete symmetry $T_7$
responsible for the fermion masses. Neutrinos get masses from only anti-sextets
which are in triplets $\underline{3}$ and $\underline{3}^*$ under $T_7$. The
flavor mixing patterns and mass splitting are obtained without perturbation.
The tribimaximal form obtained with the breaking $T_7 \rightarrow Z_3$ in
charged lepton sector and both $T_7 \rightarrow Z_3$ and $Z_3 \rightarrow
\{\mathrm{Identity}\}$ must be taken place in neutrino sector but only apart in
breakings $Z_3 \rightarrow \{\mathrm{Identity}\}$ (without contribution of
$\si'$), and the upper bound on neutrino mass $\sum_{i=1}^3m_i$ at the level is
presented. The Dirac CP violation phase $\delta$ is predicted to either
  $\frac{\pi}{2}$ or $\frac{3\pi}{2}$ which is maximal CP violation. From the
Dirac CP violation phase we obtain the relation between Euler's angles which is
consistent with the experimental in PDG 2012. On the other hand, the realistic
lepton mixing can be obtained if both the direction for breakings $T_7
\rightarrow Z_3$ and $Z_3 \rightarrow \{\mathrm{Identity}\}$ are taken place in
neutrino sectors. The CKM matrix is the identity matrix at the tree-level.Comment: 39 pages, 16 figures. arXiv admin note: substantial text overlap with
  arXiv:1312.5034; and text overlap with arXiv:1304.0921, arXiv:1306.4138,
  arXiv:1311.6729, arXiv:1310.4614 by other author
Reanalyzing the upper limit on the tensor-to-scalar perturbation ratio
  r_T in a quartic potential inflationary model

We study the polynomial chaotic inflation model with a single scalar field in
a double well quartic potential which has recently been shown to be consistent
with Planck data. In particular, we study the effects of lifting the degeneracy
between the two vacua on the inflationary observables, i.e. spectral index n_s
and tensor-to-scalar perturbation ratio r_T. We find that removing the
degeneracy allows the model to satisfy the upper limit constraints on r_T from
Planck data, provided the field starts near the local maximum. We also
calculate the scalar power spectrum and non-Gaussianity parameter f_NL for the
primordial scalar perturbations in this model.Comment: 7 pages, 7 figures; v2: discussion added, submitted to Phys. Lett. B;
  v3: published versio
Poles in the $S$-Matrix of Relativistic Chern-Simons Matter theories
  from Quantum Mechanics

An all orders formula for the $S$-matrix for 2 $\rightarrow$ 2 scattering in
large N Chern-Simons theory coupled to a fundamental scalar has recently been
conjectured. We find a scaling limit of the theory in which the pole in this
$S$-matrix is near threshold. We argue that the theory must be well described
by non-relativistic quantum mechanics in this limit, and determine the relevant
Schroedinger equation. We demonstrate that the $S$-matrix obtained from this
Schroedinger equation agrees perfectly with this scaling limit of the
relativistic $S$-matrix; in particular the pole structures match exactly. We
view this matching as a nontrivial consistency check of the conjectured field
theory $S$-matrix.Comment: 12 pages, minor correction
Moduli Space and Scattering of D0-Branes in Noncommutative Super
  Yang-Mills Theory

We study the moduli space of the D0-brane system on Dp-branes realized in the
noncommutative super Yang-Mills theory. By examining the fluctuations around
the solitonic solutions generated by solution generating technique, we confirm
the interpretation of the moduli as the positions of D0-branes on Dp-branes.
Low-energy scattering process is also examined for two D0-branes. We find that
the D0-branes scatter at right angle for head-on collision in the D0-D4 system.
For D0-D6 and D0-D8 systems we find special solutions which reduce to the D0-D4
case, giving the same behavior. This suggests that the scattering at right
angle for head-on collision is a universal behavior of this kind of soliton
scatterings.Comment: 12 pages, 1 figure; note added, references added; v3: minor
  correction, version to appear in PL
Single-spin Azimuthal Asymmetries in the "Reduced Twist-3 Approximation"

We consider the single-spin azimuthal asymmetries recently measured at theHERMES experiment for charged pions produced in semi-inclusive deep inelasticscattering of leptons off longitudinally polarized protons. Guided by theexperimental results and assuming a vanishing twist-2 transverse quark spindistribution in the longitudinally polarized nucleon, denoted as ``reducedtwist-3 approximation'', a self-consistent description of the observedsingle-spin asymmetries is obtained. In addition, predictions are given for thez dependence of the single target-spin asymmetry