pinecone/core-2020-05-10-deduplication huggingface dataset:
Micro-LED pumped polymer laser : a discussion of future pump sources for organic lasers

Optical pumping conditions for organic solid-state lasers (OSLs) are discussed with particular emphasis on the use of gallium nitride based light-emitting diodes (LEDs) as pump sources. LEDs operate in a regime where the pump should be optimized for a short rise time and high peak intensity, whereas fall time and overall pulse duration are less important. Lasers pumped with this approach need to have very low thresholds which can now be routinely created using (one-dimensional) distributed feedback lasers. In this particular case stripe-shaped excitation with linearly polarized light is beneficial. Arrays of micron-sized flip-chip LEDs have been arranged in an appropriate stripe shape and the array dimensions were chosen such that the divergence of LED emission does not cause a loss in peak intensity. These micro-LED arrays have successfully been used to pump OSLs with thresholds near 300 W/cm2 (∼9 ns rise time, 35 ns pulse duration), paving the way for compact arrays of indirectly electrically pumped OSLs
U–Pb SHRIMP zircon dating of Grenvillian metamorphism in Western Sierras Pampeanas (Argentina): Correlation with the Arequipa-Antofalla craton and constraints on the extent of the Precordillera Terrane

Metamorphism of Grenvillian age (ca. 1.2 Ga; U–Pb zircon dating) is recognized for the first time in the Western Sierras Pampeanas (Sierra de Maz). Conditions reached granulite facies (ca. 780 °C and ca. 780 MPa). Comparing geochronological and petrological characteristics with other outcrops of Mesoproterozoic basement, particularly in the northern and central Arequipa-Antofalla craton, we suggest that these regions were part of a single continental crustal block from Mesoproterozoic times, and thus autochthonous or parautochthonous to Gondwana
Educating for digital futures : what the learning strategies of digital media professionals can teach higher education

This article explores how universities might engage more effectively with the imperative to develop students’ 21st century skills for the information society, by examining learning challenges and professional learning strategies of successful digital media professionals. The findings of qualitative interviews with professionals from Australian games, online publishing, apps and software development companies reinforce an increasing body of literature that suggests that legacy university structures and pedagogical approaches are not conducive to learning for professional capability in the digital age. Study participants were ambivalent about the value of higher education to digital careers, in general preferring a range of situated online and face-to-face social learning strategies for professional currency. This article draws upon the learning preferences of the professionals in this study to present a model of 21st century learning, as linked with extant theory relating to informal, self-determined learning and communities of practice
Modeling the dispersal of an active region : quantifying energy input into the corona

Funding: UK STFC. Royal Society Research Grants Scheme.In this paper, a new technique for modeling nonlinear force-free fields directly from line-of-sight magnetogram observations is presented. The technique uses sequences of magnetograms directly as lower boundary conditions to drive the evolution of coronal magnetic fields between successive force-free equilibria over long periods of time. It is illustrated by applying it to SOHO: MDI observations of a decaying active region, NOAA AR 8005. The active region is modeled during a four-day period around its central meridian passage. Over this time, the dispersal of the active region is dominated by random motions due to small-scale convective cells. Through studying the buildup of magnetic energy in the model, it is found that such small-scale motions may inject anywhere from (2.5-3) × 1025 erg s-1 of free magnetic energy into the coronal field. Most of this energy is stored within the center of the active region in the low corona, below 30 Mm. After four days, the buildup of free energy is 10% that of the corresponding potential field. This energy buildup is sufficient to explain the radiative losses at coronal temperatures within the active region. Small-scale convective motions therefore play an integral part in the energy balance of the corona. This new technique has wide ranging applications with the new high-resolution, high-cadence observations from the SDO:HMI and SDO:AIA instruments.Publisher PDFPeer reviewe
Trajectory Clustering and an Application to Airspace Monitoring

This paper presents a framework aimed at monitoring the behavior of aircraft
in a given airspace. Nominal trajectories are determined and learned using data
driven methods. Standard procedures are used by air traffic controllers (ATC)
to guide aircraft, ensure the safety of the airspace, and to maximize the
runway occupancy. Even though standard procedures are used by ATC, the control
of the aircraft remains with the pilots, leading to a large variability in the
flight patterns observed. Two methods to identify typical operations and their
variability from recorded radar tracks are presented. This knowledge base is
then used to monitor the conformance of current operations against operations
previously identified as standard. A tool called AirTrajectoryMiner is
presented, aiming at monitoring the instantaneous health of the airspace, in
real time. The airspace is "healthy" when all aircraft are flying according to
the nominal procedures. A measure of complexity is introduced, measuring the
conformance of current flight to nominal flight patterns. When an aircraft does
not conform, the complexity increases as more attention from ATC is required to
ensure a safe separation between aircraft.Comment: 15 pages, 20 figure
Neutrino dimuon production and the dynamical determination of strange
  parton distributions

Utilizing recent neutrino dimuon production measurement from NuTeV the
assumptions on the determination of the strangeness content of the nucleon
within the dynamical approach to parton distributions are investigated. The
data are found to be in good agreement with the predictions derived from our
(GJR08) dynamical parton distributions, which have been generated entirely
radiatively starting from vanishing strange input distributions at an optimally
chosen low resolution scale. Further, the data induce an asymmetry in the
strange sea which is found to be small and positive in agreement with previous
results.Comment: 6 pages, 2 figure
Ion-dependent dynamics of DNA ejections for bacteriophage lambda

We study the control parameters that govern the dynamics of in vitro DNA
ejection in bacteriophage lambda. Past work has demonstrated that bacteriophage
DNA is highly pressurized; this pressure has been hypothesized to help drive
DNA ejection. Ions influence this process by screening charges on DNA; however,
a systematic variation of salt concentrations to explore these effects has not
been undertaken. To study the nature of the forces driving DNA ejection, we
performed in vitro measurements of DNA ejection in bulk and at the single-phage
level. We present measurements on the dynamics of ejection and on the
self-repulsion force driving ejection. We examine the role of ion concentration
and identity in both measurements, and show that the charge of counter-ions is
an important control parameter. These measurements show that the frictional
force acting on the ejecting DNA is subtly dependent on ionic concentrations
for a given amount of DNA in the capsid. We also present evidence that phage
DNA forms loops during ejection; we confirm that this effect occurs using
optical tweezers. We speculate this facilitates circularization of the genome
in the cytoplasm.Comment: David Wu and David Van Valen contributed equally to this project. 28
  pages (including supplemental information), 4 figure
On the Singular Weyl-Titchmarsh Function of Perturbed Spherical
  Schroedinger Operators

We investigate the singular Weyl-Titchmarsh m-function of perturbed spherical
Schroedinger operators (also known as Bessel operators) under the assumption
that the perturbation $q(x)$ satisfies $x q(x) \in L^1(0,1)$. We show existence
plus detailed properties of a fundamental system of solutions which are entire
with respect to the energy parameter. Based on this we show that the singular
m-function belongs to the generalized Nevanlinna class and connect our results
with the theory of super singular perturbations.Comment: 35 page
AMADEUS - The Acoustic Neutrino Detection Test System of the ANTARES
  Deep-Sea Neutrino Telescope

The AMADEUS (ANTARES Modules for the Acoustic Detection Under the Sea) system
which is described in this article aims at the investigation of techniques for
acoustic detection of neutrinos in the deep sea. It is integrated into the
ANTARES neutrino telescope in the Mediterranean Sea. Its acoustic sensors,
installed at water depths between 2050 and 2300 m, employ piezo-electric
elements for the broad-band recording of signals with frequencies ranging up to
125 kHz. The typical sensitivity of the sensors is around -145 dB re 1V/muPa
(including preamplifier). Completed in May 2008, AMADEUS consists of six
"acoustic clusters", each comprising six acoustic sensors that are arranged at
distances of roughly 1 m from each other. Two vertical mechanical structures
(so-called lines) of the ANTARES detector host three acoustic clusters each.
Spacings between the clusters range from 14.5 to 340 m. Each cluster contains
custom-designed electronics boards to amplify and digitise the acoustic signals
from the sensors. An on-shore computer cluster is used to process and filter
the data stream and store the selected events. The daily volume of recorded
data is about 10 GB. The system is operating continuously and automatically,
requiring only little human intervention. AMADEUS allows for extensive studies
of both transient signals and ambient noise in the deep sea, as well as signal
correlations on several length scales and localisation of acoustic point
sources. Thus the system is excellently suited to assess the background
conditions for the measurement of the bipolar pulses expected to originate from
neutrino interactions.Comment: 36 pages, 19 figures; v3: Line numbers removed (no changes to text
Permutation Orbifold of N=2 Supersymmetric Minimal Models

In this paper we apply the previously derived formalism of permutation
orbifold conformal field theories to N=2 supersymmetric minimal models. By
interchanging extensions and permutations of the factors we find a very
interesting structure relating various conformal field theories that seems not
to be known in literature. Moreover, unexpected exceptional simple currents
arise in the extended permuted models, coming from off-diagonal fields. In a
few situations they admit fixed points that must be resolved. We determine the
complete CFT data with all fixed point resolution matrices for all simple
currents of all Z_2-permutations orbifolds of all minimal N=2 models with k\neq
2 mod 4.Comment: 48 page
Studies of a sample of 6C radio galaxies at redshift one, I -- Deep
  multi-frequency radio observations

Deep radio observations at 5 and 8 GHz are presented of a complete sample of
11 radio galaxies with redshifts 0.85 < z < 1.5, selected from the 6C sample of
Eales. The radio data, taken using the VLA in A, B and C array configurations,
provide a best angular resolution of 0.25'' and reach an rms noise level of
order 20 microJy. Radio core candidates are detected in 8 of the 11 sources. 9
of the 11 sources display deviations from `standard double radio source'
morphologies, with multiple hotspots or a hotspot withdrawn from the leading
edge of the radio emission. The sources are typically polarised at the 5 to 15%
level. The mean rotation measures of the individual lobes are less than 50
rad/m^2 but strong asymmetries between the two lobes indicate that the Faraday
rotation does not have a Milky Way origin; rather, the distant 6C radio sources
lie in a relatively dense clumpy environment. The sources are compared with the
more radio powerful distant 3CR radio galaxies and with low redshift sources.
The ratio of core to extended radio flux is almost independent of the radio
source size and only weakly inversely correlated with the total radio power.
This indicates that the high radio luminosity of the most powerful radio
sources must originate in the AGN, in contrast to the suggestion that they are
so luminous only due to confinement by a dense surrounding environment.
Environmental effects play a secondary role. (Abridged)Comment: 31 pages LaTeX (of which 22 pages of figures). Accepted for
  publication in MNRA
KK Gravitons and Unitarity Violation in the Randall-Sundrum Model

We show that perturbative unitarity for $W_LW_L$ scattering places
significant constraints on the Randall-Sundrum theory with two 3-branes, with
matter confined to the TeV brane. The exchange of massive 4D Kaluza-Klein
gravitons leads to amplitudes growing linearly with the CM energy squared.
Summing over KK gravitons up to a scale $\lbar$ and testing unitarity at $\sqrt
s=\lbar$, one finds that unitarity is violated for $\lbar$ below the 'naive
dimensional analysis' scale, $\Lambda_{NDA}$. We evaluate $\lbar$ as a function
of the curvature ratio $m_0/M_{Planck}$ for the pure gravity theory. We then
demonstrate that unitarity need not be violated at $\lbar$ in the presence of a
heavy Higgs boson. In fact, much larger Higgs masses are consistent with
unitarity than if no KK gravitons are present. Observation of the mass and
width (or cross section) of one or more KK gravitons at the LHC will directly
determine $m_0/M_{Planck}$ and the scale $\hat \Lambda$ specifying the
couplings of matter to the KK gravitons. With this information in hand and a
measurement of the Higgs boson mass, one can determine the precise scale
$\lbar$ below which unitarity will remain valid.Comment: 14 pages, 8 figures, major revisions mad
S-Duality and Modular Transformation as a non-perturbative deformation
  of the ordinary pq-duality

A recent claim that the S-duality between 4d SUSY gauge theories, which is
AGT related to the modular transformations of 2d conformal blocks, is no more
than an ordinary Fourier transform at the perturbative level, is further traced
down to the commutation relation [P,Q]=-i\hbar between the check-operator
monodromies of the exponential resolvent operator in the underlying
Dotsenko-Fateev matrix models and beta-ensembles. To this end, we treat the
conformal blocks as eigenfunctions of the monodromy check operators, what is
especially simple in the case of one-point toric block. The kernel of the
modular transformation is then defined as the intertwiner of the two
monodromies, and can be obtained straightforwardly, even when the eigenfunction
interpretation of the blocks themselves is technically tedious. In this way, we
provide an elementary derivation of the old expression for the modular kernel
for the one-point toric conformal block.Comment: 15 page
A functional RG equation for the c-function

After showing how to prove the integrated c-theorem within the functional RG
framework based on the effective average action, we derive an exact RG flow
equation for Zamolodchikov's c-function in two dimensions by relating it to the
flow of the effective average action. In order to obtain a non-trivial flow for
the c-function, we will need to understand the general form of the effective
average action away from criticality, where nonlocal invariants, with beta
functions as coefficients, must be included in the ansatz to be consistent. We
then apply our construction to several examples: exact results, local potential
approximation and loop expansion. In each case we construct the relative
approximate c-function and find it to be consistent with Zamolodchikov's
c-theorem. Finally, we present a relation between the c-function and the
(matter induced) beta function of Newton's constant, allowing us to use heat
kernel techniques to compute the RG running of the c-function.Comment: 41 pages, 17 figures; v2: some minor correction
Eckhaus-like instability of large scale coherent structures in a fully
  turbulent von K\'arm\'an flow

The notion of instability of a turbulent flow is introduced in the case of a
von K\'arm\'an flow thanks to the monitoring of the spatio-temporal spectrum of
the velocity fluctuations, combined with projection onto suitable Beltrami
modes. It is shown that the large scale coherent fluctuations of the flow obeys
a sequence of Eckhaus instabilities when the Reynolds number $\mathrm{Re}$ is
varied from $10^2$ to $10^6$. This sequence results in modulations of
increasing azimuthal wavenumber. The basic state is the laminar or
time-averaged flow at an arbitrary $\mathrm{Re}$, which is axi-symmetric, i.e.
with a $0$ azimuthal wavenumber. Increasing $\mathrm{Re}$ leads to
non-axisymmetric modulations with increasing azimuthal wavenumber from $1$ to
$3$. These modulations are found to rotate in the azimuthal direction. However
no clear rotation frequency can be established until $\mathrm{Re}\approx
4\times 10^3$. Above, they become periodic with an increasing frequency. We
finally show that these modulations are connected with the coherent structures
of the mixing shear layer. The implication of these findings for the turbulence
parametrization is discussed. Especially, they may explain why simple eddy
viscosity models are able to capture complex turbulent flow dynamics
Fossil Groups Origins III. The relation between optical and X-ray
  luminosities

This study is part of the FOssil Groups Origin (FOGO) project which aims at
carrying out a systematic and multiwavelength study of a large sample of fossil
systems. Here we focus on the relation between the optical luminosity (Lopt)
and X-ray luminosity (Lx). Out of a sample of 28 candidate fossil systems, we
consider a sample of 12 systems whose fossil classification has been confirmed
by a companion study. They are compared with the complementary sample of 16
systems whose fossil nature is not confirmed and with a subsample of 102 galaxy
systems from the RASS-SDSS galaxy cluster survey. Fossil and normal systems
span the same redshift range 0<z<0.5 and have the same Lx distribution. For
each fossil system, the Lx in the 0.1-2.4 keV band is computed using data from
the ROSAT All Sky Survey. For each fossil and normal system we homogeneously
compute Lopt in the r-band within the characteristic cluster radius, using data
from the SDSS DR7. We sample the Lx-Lopt relation over two orders of magnitude
in Lx. Our analysis shows that fossil systems are not statistically
distinguishable from the normal systems both through the 2D KS test and the fit
of the Lx-Lopt relation. The optical luminosity of the galaxy system does
strongly correlate with the X-ray luminosity of the hot gas component,
independently of whether the system is fossil or not. We conclude that our
results are consistent with the classical "merging scenario" of the brightest
galaxy formed via merger/cannibalism of other group galaxies, with conservation
of the optical light. We find no evidence for a peculiar state of the hot
intracluster medium.Comment: A&A, 12 pages, 4 figures, 3 tables, typos corr. and paper re-numbe
The Gaia-ESO Survey: processing of the FLAMES-UVES spectra

The Gaia-ESO Survey is a large public spectroscopic survey that aims to
derive radial velocities and fundamental parameters of about 10^5 Milky Way
stars in the field and in clusters. Observations are carried out with the
multi-object optical spectrograph FLAMES, using simultaneously the medium
resolution (R~20,000) GIRAFFE spectrograph and the high resolution (R~47,000)
UVES spectrograph. In this paper, we describe the methods and the software used
for the data reduction, the derivation of the radial velocities, and the
quality control of the FLAMES-UVES spectra. Data reduction has been performed
using a workflow specifically developed for this project. This workflow runs
the ESO public pipeline optimizing the data reduction for the Gaia-ESO Survey,
performs automatically sky subtraction, barycentric correction and
normalisation, and calculates radial velocities and a first guess of the
rotational velocities. The quality control is performed using the output
parameters from the ESO pipeline, by a visual inspection of the spectra and by
the analysis of the signal-to-noise ratio of the spectra.
  Using the observations of the first 18 months, specifically targets observed
multiple times at different epochs, stars observed with both GIRAFFE and UVES,
and observations of radial velocity standards, we estimated the precision and
the accuracy of the radial velocities. The statistical error on the radial
velocities is sigma~0.4 km s^-1 and is mainly due to uncertainties in the zero
point of the wavelength calibration. However, we found a systematic bias with
respect to the GIRAFFE spectra (~0.9 km s^-1) and to the radial velocities of
the standard stars (~0.5 kms^-1) retrieved from the literature. This bias will
be corrected in the future data releases, when a common zero point for all the
setups and instruments used for the survey will be established.Comment: 11 pages, 7 figures, accepted for publication on A&
Electroweak Phase Transition in Georgi-Machacek Model

The Georgi-Machacek model extends the standard model Higgs sector by adding
two isospin triplet scalar fields and imposing global SU(2)$_R$ symmetry on
them. A feature of the model is that the triplets can acquire a large vacuum
expectation value without conflicting with the current experimental bound on
the $\rho$ parameter. We investigate the electroweak phase transition in the
Georgi-Machacek model by evaluating the finite-temperature effective potential
of the Higgs sector. The electroweak phase transition can be sufficiently
strong in a large parameter space when the triplets acquire a vacuum
expectation value of $O(10)$ GeV, opening a possibility to realize successful
electroweak baryogenesis
Dark energy, inflation and the cosmic coincidence problem

We show that holographic dark energy could explain why the current dark
energy density is so small, if there was an inflation with a sufficient
expansion in the early universe. It is also suggested that an inflation with
the number of e-folds $N\simeq 65$ may solve the cosmic coincidence problem in
this context. Assuming the inflation and the power-law acceleration phase today
we obtain approximate formulas for the event horizon size of the universe and
dark energy density as functions of time. A simple numerical study exploiting
the formula well reproduces the observed evolution of dark energy. This
nontrivial match between the theory and the observational data supports both
inflation and holographic dark energy models.Comment: final versio
A note on the Harris-Kesten Theorem

Recently, a short proof of the Harris-Kesten result that the critical
probability for bond percolation in the planar square lattice is 1/2 was given,
using a sharp threshold result of Friedgut and Kalai. Here we point out that a
key part of this proof may be replaced by an argument of Russo from 1982, using
his approximate zero-one law in place of the Friedgut-Kalai result. Russo's
paper gave a new proof of the Harris-Kesten Theorem that seems to have received
little attention.Comment: 4 pages; author list changed, acknowledgement adde