pinecone/core-2020-05-10-deduplication huggingface dataset:
Search for very-high-energy γ-ray emission from galactic globular clusters with H.E.S.S.

Context: Globular clusters (GCs) are established emitters of high-energy (HE, 100 MeV < E < 100 GeV) γ-ray radiation which could originate from the cumulative emission of the numerous millisecond pulsars (msPSRs) in the clusters’ cores or from inverse Compton (IC) scattering of relativistic leptons accelerated in the GC environment. These stellar clusters could also constitute a new class of sources in the very-high-energy (VHE, E > 100 GeV) γ-ray regime, judging from the recent detection of a signal from the direction of Terzan 5 with the H.E.S.S. telescope array.
Aims: To search for VHE γ-ray sources associated with other GCs, and to put constraints on leptonic emission models, we systematically analyzed the observations towards 15 GCs taken with the H.E.S.S. array of imaging atmospheric Cherenkov telescopes.
Methods: We searched for point-like and extended VHE γ-ray emission from each GC in our sample and also performed a stacking analysis combining the data from all GCs to investigate the hypothesis of a population of faint emitters. Assuming IC emission as the origin of the VHE γ-ray signal from the direction of Terzan 5, we calculated the expected γ-ray flux from each of the 15 GCs, based on their number of millisecond pulsars, their optical brightness and the energy density of background photon fields.
Results: We did not detect significant VHE γ-ray emission from any of the 15 GCs in either of the two analyses. Given the uncertainties related to the parameter determinations, the obtained flux upper limits allow to rule out the simple IC/msPSR scaling model for NGC 6388 and NGC 7078. The upper limits derived from the stacking analyses are factors between 2 and 50 below the flux predicted by the simple leptonic scaling model, depending on the assumed source extent and the dominant target photon fields. Therefore, Terzan 5 still remains exceptional among all GCs, as the VHE γ-ray emission either arises from extra-ordinarily efficient leptonic processes, or from a recent catastrophic event, or is even unrelated to the GC itself.http://dx.doi.org/10.1051/0004-6361/201220719http://www.aanda.org/articles/aa/pdf/2013/03/aa20719-12.pd
Compact finite difference modeling of 2-D acoustic wave propagation

We present two fourth-order compact finite difference (CFD) discretizations of the velocity–pressure formulation of the acoustic wave equation in 2-D rectangular grids. The first method uses standard implicit CFD on nodal meshes and requires solving tridiagonal linear systems along each grid line, while the second scheme employs a novel set of mimetic CFD operators for explicit differentiation on staggered grids. Both schemes share a Crank–Nicolson time integration decoupled by the Peaceman–Rachford splitting technique to update discrete fields by alternating the coordinate direction of CFD differentiation (ADI-like iterations). For comparison purposes, we also implement a spatially fourth-order FD scheme using non compact staggered mimetic operators in combination to second-order leap-frog time discretization. We apply these three schemes to model acoustic motion under homogeneous boundary conditions and compare their experimental convergence and execution times, as grid is successively refined. Both CFD schemes show four-order convergence, with a slight superiority of the mimetic version, that leads to more accurate results on fine grids. Conversely, the mimetic leap-frog method only achieves quadratic convergence and shows similar accuracy to CFD results exclusively on coarse grids. We finally observe that computation times of nodal CFD simulations are between four and five times higher than those spent by the mimetic CFD scheme with similar grid size. This significant performance difference is attributed to solving those embedded linear systems inherent to implicit CFD.Peer ReviewedPreprin
Intracellular zinc modulates cardiac ryanodine receptor-mediated calcium release.

Aberrant Zn(2+)-homeostasis is a hallmark of certain cardiomyopathies associated with altered contractile force. In this study we addressed whether Zn(2+) modulates cardiac ryanodine receptor gating and Ca(2+)-dynamics in isolated cardiomyocytes. We reveal that Zn(2+) is a high affinity regulator of RyR2 displaying three modes of operation. Picomolar free Zn(2+) concentrations potentiate RyR2 responses but channel activation is still dependent on the presence of cytosolic Ca(2+). At concentrations of free Zn(2+) >1 nM, Zn(2+) is the main activating ligand and the dependency on Ca(2+) is removed. Zn(2+) is therefore a higher affinity activator of RyR2 than Ca(2+). Millimolar levels of free Zn(2+) were found to inhibit channel openings. In cardiomyocytes, consistent with our single-channel results, we show that Zn(2+) modulates both the frequency and amplitude of Ca(2+) waves in a concentration dependent manner and that physiological levels of Zn(2+) elicit Ca(2+)-release in the absence of activating levels of cytosolic Ca(2+). This highlights a new role for intracellular Zn(2+) in shaping Ca(2+)-dynamics in cardiomyocytes through modulation of RyR2 gating.This work was supported by University of St. Andrews, Tenovus Scotland Grant T14/35 (to S. J. P.), British Heart Foundation Grant FS/14/69/31001 (to S. J. P.), a grant from the John and Lucille van Geest Cardiovascular Diseases Research Fund (to the University of Leicester and R. D. R.), and Biotechnology and Biological Sciences Research Council Grant BB/J006467/1 (to A. J. S.).Peer-reviewedPublisher Versio
Bootstrapping correlation functions in N = 4 SYM.

We describe a new approach to computing the chiral part of correlation functions of stress-tensor supermultiplets in  N=4N=4  SYM that relies on symmetries, analytic properties and the structure of the OPE only. We demonstrate that the correlation functions are given by a linear combination of chiral  N=4N=4  superconformal invariants accompanied by coefficient functions depending on the space-time coordinates only. We present the explicit construction of these invariants and show that the six-point correlation function is fixed in the Born approximation up to four constant coefficients by its symmetries. In addition, the known asymptotic structure of the correlation function in the light-like limit fixes unambiguously these coefficients up to an overall normalization. We demonstrate that the same approach can be applied to obtain a representation for the six-point NMHV amplitude that is free from any auxiliary gauge fixing parameters, does not involve spurious poles and manifests half of the dual superconformal symmetry
Deactivation behavior of Pd/C and Pt/C catalysts in the gas-phase hydrodechlorination of chloromethanes : structure-reactivity relationship

The authors acknowledge financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) through the project CTM2011-28352. M. Martín Martínez acknowledges the Spanish Ministerio de Ciencia e Innovación (MICINN) and the European Social Fund (ESF) for her research grant.This study analyzes the influence of chemical and physical properties of Pd/C and Pt/C hydrodechlorination (HDC) catalysts in the different evolution of their activity during time on stream. Pt/C showed stable activity in the HDC of dichloromethane (DCM) and chloroform (TCM), while Pd/C was deactivated after 90h of operation, particularly during HDC of DCM. The deactivation of Pd/C catalyst can be attributed to the lower proportion of zero-valent species and larger metal particle size. This appears to hinder the H dissociation, enhance the irreversible chemisorption of reactants and reaction products, and favor coupling reactions (leading to the formation of carbonaceous deposits) and/or metal phase change reactions. The more extensive deactivation of Pd/C in the HDC of DCM is attributed to the stronger chemisorption of the reactant on the catalyst, which leads to the formation of a new PdC phase by the incorporation of carbon atoms into the metal lattice.PostprintPeer reviewe
Anatomy of molecular structures in $^{20}$Ne

We present a beyond mean-field study of clusters and molecular structures in
low-spin states of $^{20}$Ne with a multireference relativistic energy density
functional, where the dynamical correlation effects of symmetry restoration and
quadrupole-octupole shapes fluctuation are taken into account with projections
on parity, particle number and angular momentum in the framework of the
generator coordinate method. Both the energy spectrum and the electric
multipole transition strengths for low-lying parity-doublet bands are better
reproduced after taking into account the dynamical octupole vibration effect.
Consistent with the finding in previous studies, a rotation-induced dissolution
of the $\alpha+^{16}$O molecular structure in $^{20}$Ne is predicted.Comment: 6 pages with 6 figures, version to be published in Phys. Lett.
Measurement of fiducial differential cross sections of gluon-fusion
  production of Higgs bosons decaying to $WW^{\ast}{\rightarrow\,}e\nu\mu\nu$
  with the ATLAS detector at $\sqrt{s}=8$ TeV

This paper describes a measurement of fiducial and differential cross
sections of gluon-fusion Higgs boson production in the
$H{\rightarrow\,}WW^{\ast}{\rightarrow\,}e\nu\mu\nu$ channel, using 20.3
fb$^{-1}$ of proton-proton collision data. The data were produced at a
centre-of-mass energy of $\sqrt{s} = 8$ TeV at the CERN Large Hadron Collider
and recorded by the ATLAS detector in 2012. Cross sections are measured from
the observed $H{\rightarrow\,}WW^{\ast}{\rightarrow\,}e\nu\mu\nu$ signal yield
in categories distinguished by the number of associated jets. The total cross
section is measured in a fiducial region defined by the kinematic properties of
the charged leptons and neutrinos. Differential cross sections are reported as
a function of the number of jets, the Higgs boson transverse momentum, the
dilepton rapidity, and the transverse momentum of the leading jet. The jet-veto
efficiency, or fraction of events with no jets above a given transverse
momentum threshold, is also reported. All measurements are compared to QCD
predictions from Monte Carlo generators and fixed-order calculations, and are
in agreement with the Standard Model predictions.Comment: 44 pages plus author list + cover pages (61 pages total), 8 figures,
  20 tables, submitted to JHEP. All figures including auxiliary figures are
  available at
  https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HIGG-2015-04
Dendritic spikes induce ripples in parvalbumin interneurons during hippocampal sharp waves.

Sharp-wave ripples are transient oscillatory events in the hippocampus that are associated with the reactivation of neuronal ensembles within specific circuits during memory formation. Fast-spiking, parvalbumin-expressing interneurons (FS-PV INs) are thought to provide fast integration in these oscillatory circuits by suppressing regenerative activity in their dendrites. Here, using fast 3D two-photon imaging and a caged glutamate, we challenge this classical view by demonstrating that FS-PV IN dendrites can generate propagating Ca(2+) spikes during sharp-wave ripples. The spikes originate from dendritic hot spots and are  mediated dominantly by L-type Ca(2+) channels. Notably, Ca(2+) spikes were associated with intrinsically generated membrane potential oscillations. These oscillations required the activation of voltage-gated Na(+) channels, had the same frequency as the field potential oscillations associated with sharp-wave ripples, and controlled the phase of action potentials. Furthermore, our results  demonstrate that the smallest functional unit that can generate ripple-frequency  oscillations is a segment of a dendrite
Measurement of the B± production cross-section in pp collisions at s√=7 TeV

The production of B ± mesons in proton-proton collisions at s√ = 7 TeV is studied using 35 pb−1 of data collected by the LHCb detector. The B ± mesons are reconstructed exclusively in the B ± → J/ψK ± mode, with J/ψ → μ + μ −. The differential production cross-section is measured as a function of the B ± transverse momentum in the fiducial region 0 < p T < 40 GeV/c and with rapidity 2.0 < y < 4.5. The total cross-section, summing up B + and B −, is measured to be σ(pp → B ± X, 0 < p T < 40 GeV/c, 2.0 < y < 4.5) = 41.4 ± 1.5 (stat.) ± 3.1 (syst.) μb
Forward $\pi^{+-}$ production in p-$O_2$ and p-$N_2$ interactions at 12 GeV/c

Measurements of double-differential charged pion production cross-sections in interactions of 12 GeV/c protons on O_2 and N_2 thin targets are presented in the kinematic range 0.5 GeV/c < p_{\pi} < 8 GeV/c and 50 mrad < \theta_{\pi} < 250 mrad (in the laboratory frame) and are compared with p--C results. For p--N_2 (p--O_2) interactions the analysis is performed using 38576 (7522) reconstructed secondary pions. The analysis uses the beam instrumentation and the forward spectrometer of the HARP experiment at CERN PS. The measured cross-sections have a direct impact on the precise calculation of atmospheric neutrino fluxes and on the improved reliability of extensive air shower simulations by reducing the uncertainties of hadronic interaction models in the low energy range. In particular, the present results allow the common hypothesis that p--C data can be used to predict the p--N_2 and p--O_2 pion production cross-sections to be tested.Measurements of double-differential charged pion production cross-sections in interactions of 12 GeV/c protons on O_2 and N_2 thin targets are presented in the kinematic range 0.5 GeV/c &lt; p_{\pi} &lt; 8 GeV/c and 50 mrad &lt; \theta_{\pi} &lt; 250 mrad (in the laboratory frame) and are compared with p--C results. For p--N_2 (p--O_2) interactions the analysis is performed using 38576 (7522) reconstructed secondary pions. The analysis uses the beam instrumentation and the forward spectrometer of the HARP experiment at CERN PS. The measured cross-sections have a direct impact on the precise calculation of atmospheric neutrino fluxes and on the improved reliability of extensive air shower simulations by reducing the uncertainties of hadronic interaction models in the low energy range. In particular, the present results allow the common hypothesis that p--C data can be used to predict the p--N_2 and p--O_2 pion production cross-sections to be tested
Limited microstructural and connectivity deficits despite subcortical volume reductions in school-aged children born preterm with very low birth weight.

Preterm birth and very low birth weight (VLBW, ≤ 1500 g) are worldwide problems that burden survivors with lifelong cognitive, psychological, and physical challenges. In this multimodal structural magnetic resonance imaging (MRI) and diffusion MRI (dMRI) study, we investigated differences in subcortical brain volumes and white matter tract properties in children born preterm with VLBW compared to term-born controls (mean age = 8 years). Subcortical brain structure volumes and cortical thickness estimates were obtained, and fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD), and axial diffusivity (AD) were generated for 18 white matter tracts. We also assessed structural relationships between white matter tracts and cortical thickness of the tract endpoints. Compared to controls, the VLBW group had reduced volumes of thalamus, globus pallidus, corpus callosum, cerebral white matter, ventral diencephalon, and brain stem, while the ventricular system was larger in VLBW subjects, after controlling for age, sex, IQ, and estimated total intracranial volume. For the dMRI parameters, group differences were not significant at the whole-tract level, though pointwise analysis found shorter segments affected in forceps minor and left superior longitudinal fasciculus – temporal bundle. IQ did not correlate with subcortical volumes or dMRI measures in the VLBW group. While the deviations in subcortical volumes were substantial, there were few differences in dMRI measures between the two groups, which may reflect the influence of advances in perinatal care on white matter development.Copyright © 2015 The Authors. Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0
Implementing Hydropower Scheduling in a European Expansion Planning Model

A method for implementing an enhanced hydropower planning formulation in a long-term expansion planning model is proposed. The methodological framework involves assigning hydropower generation a marginal cost through water values, enabling comparability with the marginal costs of competitive technologies. Added robustness and details in the representation of hydropower and its inherent storage capabilities allows for a more precise evaluation of the technology's impact on optimal investments for other power resources. The impact for intermittent renewable energy sources such as wind and solar power is especially interesting to analyze. Examination of effects from the richer formulation is carried out for an EU 20-20-20 like policy scenario. Optimization results for Europe in the period 2010 to 2060 show that the new framework leads to decreased utilization of hydropower due to its more precise valuation through water values, as well as lower inflow for run-of-the-river hydropower than previously. Therefore, additional investments are carried out for other energy sources that are deemed more economically beneficial. Notably, an earlier deployment of solar power is part of the revamped investment scheme.© 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
'Particle genetics': treating every cell as unique.

Genotype-phenotype relations are usually inferred from a deterministic point of view. For example, quantitative trait loci (QTL), which describe regions of the genome associated with a particular phenotype, are based on a mean trait difference between genotype categories. However, living systems comprise huge numbers of cells (the 'particles' of biology). Each cell can exhibit substantial phenotypic individuality, which can have dramatic consequences at the organismal level. Now, with technology capable of interrogating individual cells, it is time to consider how genotypes shape the probability laws of single cell traits. The possibility of mapping single cell probabilistic trait loci (PTL), which link genomic regions to probabilities of cellular traits, is a promising step in this direction. This approach requires thinking about phenotypes in probabilistic terms, a concept that statistical physicists have been applying to particles for a century. Here, I describe PTL and discuss their potential to enlarge our understanding of genotype-phenotype relations
Search for new particles decaying to ZZ using final states with leptons
  and jets with the ATLAS detector in sqrt(s) = 7 Tev proton-proton collisions

A search is presented for a narrow resonance decaying to a pair of Z bosons
using data corresponding to 1.02/fb of integrated luminosity collected by the
ATLAS experiment from pp collisions at sqrt(s) = 7 TeV. Events containing
either four charged leptons (llll) or two charged leptons and two jets (lljj)
are analyzed and found to be consistent with the Standard Model background
expectation. Lower limits on a resonance mass are set using the Randall-Sundrum
(RS1) graviton model as a benchmark. Using both llll and lljj events, an RS1
graviton with k/m_pl = 0.1 and mass between 325 and 845 GeV is excluded at 95%
confidence level. In addition, the llll events are used to set a fiducial cross
section limit of sigma_fiducial(pp -> X -> ZZ < 0.92 pb at 95% confidence level
for any new sources of ZZ production with m_ZZ greater than 300 GeV.Comment: 19 pages plus author list (42 pages total), 5 figures, 6 tables,
  revised author list, matches Physics Letters B versio
The host galaxies of X-ray selected active galactic nuclei to z = 2.5: Structure, star formation, and their relationships from CANDELS and Herschel/PACS

International audienceWe study the relationship between the structure and star formation rate (SFR) of X-ray selected low and moderate luminosity active galactic nuclei (AGNs) in the two Chandra Deep Fields, using Hubble Space Telescope imaging from the Cosmic Assembly Near Infrared Extragalactic Legacy Survey (CANDELS) and deep far-infrared maps from the PEP+GOODS-Herschel survey. We derive detailed distributions of structural parameters and FIR luminosities from carefully constructed control samples of galaxies, which we then compare to those of the AGNs. At z ~ 1, AGNs show slightly diskier light profiles than massive inactive (non-AGN) galaxies, as well as modestly higher levels of gross galaxy disturbance (as measured by visual signatures of interactions and clumpy structure). In contrast, at z ~ 2, AGNs show similar levels of galaxy disturbance as inactive galaxies, but display a red central light enhancement, which may arise from a more pronounced bulge in AGN hosts or extinguished nuclear light. We undertake a number of tests of both these alternatives, but our results do not strongly favor one interpretation over the other. The mean SFR and its distribution among AGNs and inactive galaxies are similar at z> 1.5. At z< 1, however, clear and significant enhancements are seen in the SFRs of AGNs with bulge-dominated light profiles. These trends suggest an evolution in the relation between nuclear activity and host properties with redshift, towards a minor role for mergers and interactions at z> 1.5
New Constraints on the Faint End of the UV Luminosity Function at z ~ 7-8 Using the Gravitational Lensing of the Hubble Frontier Fields Cluster A2744

International audienceExploiting the power of gravitational lensing, the Hubble Frontier Fields (HFF) program aims at observing six massive galaxy clusters to explore the distant Universe far beyond the depth limits of blank field surveys. Using the complete Hubble Space Telescope observations of the first HFF cluster Abell 2744, we report the detection of 50 galaxy candidates at z∼7 and eight candidates at z∼8 in a total survey area of 0.96 arcmin2 in the source plane. Three of these galaxies are multiply-imaged by the lensing cluster. Using an updated model of the mass distribution in the cluster we were able to calculate the magnification factor and the effective survey volume for each galaxy in order to compute the ultraviolet galaxy luminosity function at both redshifts 7 and 8. Our new measurements extend the z∼7 UV LF down to an absolute magnitude of MUV∼−15.5. We find a characteristic magnitude of M⋆UV=−20.63+0.69−0.56 mag and a faint-end slope α=−1.88+0.17−0.20 close to previous determinations in blank fields. We show here for the first time that this slope remains steep down to very faint luminosities of 0.01L⋆. Although prone to large uncertainties, our results at z∼8 also seem to confirm a steep faint-end slope below 0.1L⋆. The HFF program is therefore providing an extremely efficient way to study the faintest galaxy populations at z>7 that would otherwise be inaccessible with current instrumentation. The full sample of six galaxy clusters will provide yet better constraints on the build-up of galaxies at early epochs and their contribution to cosmic reionization
Elements of proof for conjectures of Witte and Forrester about the combinatorial structure of Gaussian β Ensembles

International audienceThe purpose of the article is to provide partial proofs for two conjectures given by Witte and Forrester in "Moments of the Gaussian β Ensembles and the large N expansion of the densities" with the use of the topological recursion adapted for general β Gaussian case. In particular, the paper uses a version at coinciding points that provides a simple proof for some of the coefficients involved in the conjecture. Additionally, we propose a generalized version of the conjectures for all correlation functions evaluated at coinciding point