45 research outputs found

    MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524

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    The high-frequency-peaked BL Lac (HBL) 1ES 0806+524 (z = 0.138) was discovered in VHE γ\gamma rays in 2008. Until now, the broad-band spectrum of 1ES 0806+524 has been only poorly characterized, in particular at high energies. We analysed multiwavelength observations from γ\gamma rays to radio performed from 2011 January to March, which were triggered by the high activity detected at optical frequencies. These observations constitute the most precise determination of the broad-band emission of 1ES 0806+524 to date. The stereoscopic MAGIC observations yielded a γ\gamma-ray signal above 250 GeV of (3.7±0.7)(3.7 \pm 0.7) per cent of the Crab Nebula flux with a statistical significance of 9.9 σ\sigma. The multiwavelength observations showed significant variability in essentially all energy bands, including a VHE γ\gamma-ray flare that lasted less than one night, which provided unprecedented evidence for short-term variability in 1ES 0806+524. The spectrum of this flare is well described by a power law with a photon index of 2.97±0.292.97 \pm 0.29 between \sim150 GeV and 1 TeV and an integral flux of (9.3±1.9)(9.3 \pm 1.9) per cent of the Crab Nebula flux above 250 GeV. The spectrum during the non-flaring VHE activity is compatible with the only available VHE observation performed in 2008 with VERITAS when the source was in a low optical state. The broad-band spectral energy distribution can be described with a one-zone Synchrotron Self Compton model with parameters typical for HBLs, indicating that 1ES 0806+524 is not substantially different from the HBLs previously detected.Comment: 12 pages, 8 figures, 3 tables, accepted 2015 April 20 for publication in Monthly Notices of the Royal Astronomical Society Main Journa

    The 2009 multiwavelength campaign on Mrk 421: Variability and correlation studies

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    We performed a 4.5-month multi-instrument campaign (from radio to VHE gamma rays) on Mrk421 between January 2009 and June 2009, which included VLBA, F-GAMMA, GASP-WEBT, Swift, RXTE, Fermi-LAT, MAGIC, and Whipple, among other instruments and collaborations. Mrk421 was found in its typical (non-flaring) activity state, with a VHE flux of about half that of the Crab Nebula, yet the light curves show significant variability at all wavelengths, the highest variability being in the X-rays. We determined the power spectral densities (PSD) at most wavelengths and found that all PSDs can be described by power-laws without a break, and with indices consistent with pink/red-noise behavior. We observed a harder-when-brighter behavior in the X-ray spectra and measured a positive correlation between VHE and X-ray fluxes with zero time lag. Such characteristics have been reported many times during flaring activity, but here they are reported for the first time in the non-flaring state. We also observed an overall anti-correlation between optical/UV and X-rays extending over the duration of the campaign. The harder-when-brighter behavior in the X-ray spectra and the measured positive X-ray/VHE correlation during the 2009 multi-wavelength campaign suggests that the physical processes dominating the emission during non-flaring states have similarities with those occurring during flaring activity. In particular, this observation supports leptonic scenarios as being responsible for the emission of Mrk421 during non-flaring activity. Such a temporally extended X-ray/VHE correlation is not driven by any single flaring event, and hence is difficult to explain within the standard hadronic scenarios. The highest variability is observed in the X-ray band, which, within the one-zone synchrotron self-Compton scenario, indicates that the electron energy distribution is most variable at the highest energies.Comment: Accepted for publication in A&A, 18 pages, 14 figures (v2 has a small modification in the acknowledgments, and also corrects a typo in the field "author" in the metadata

    European guideline on IgG4-related digestive disease – UEG and SGF evidence-based recommendations

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    The overall objective of these guidelines is to provide evidence-based recommendations for the diagnosis and management of immunoglobulin G4 (IgG4)-related digestive disease in adults and children. IgG4-related digestive disease can be diagnosed only with a comprehensive work-up that includes histology, organ morphology at imaging, serology, search for other organ involvement, and response to glucocorticoid treatment. Indications for treatment are symptomatic patients with obstructive jaundice, abdominal pain, posterior pancreatic pain, and involvement of extra-pancreatic digestive organs, including IgG4-related cholangitis. Treatment with glucocorticoids should be weight-based and initiated at a dose of 0.6–0.8 mg/kg body weight/day orally (typical starting dose 30-40 mg/day prednisone equivalent) for 1 month to induce remission and then be tapered within two additional months. Response to initial treatment should be assessed at week 2–4 with clinical, biochemical and morphological markers. Maintenance treatment with glucocorticoids should be considered in multi-organ disease or history of relapse. If there is no change in disease activity and burden within 3 months, the diagnosis should be reconsidered. If the disease relapsed during the 3 months of treatment, immunosuppressive drugs should be added

    Studies of η\eta and η\eta' production in pppp and ppPb collisions

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    The production of η\eta and η\eta' mesons is studied in proton-proton and proton-lead collisions collected with the LHCb detector. Proton-proton collisions are studied at center-of-mass energies of 5.025.02 and 13 TeV13~{\rm TeV}, and proton-lead collisions are studied at a center-of-mass energy per nucleon of 8.16 TeV8.16~{\rm TeV}. The studies are performed in center-of-mass rapidity regions 2.5<yc.m.<3.52.5<y_{\rm c.m.}<3.5 (forward rapidity) and 4.0<yc.m.<3.0-4.0<y_{\rm c.m.}<-3.0 (backward rapidity) defined relative to the proton beam direction. The η\eta and η\eta' production cross sections are measured differentially as a function of transverse momentum for 1.5<pT<10 GeV1.5<p_{\rm T}<10~{\rm GeV} and 3<pT<10 GeV3<p_{\rm T}<10~{\rm GeV}, respectively. The differential cross sections are used to calculate nuclear modification factors. The nuclear modification factors for η\eta and η\eta' mesons agree at both forward and backward rapidity, showing no significant evidence of mass dependence. The differential cross sections of η\eta mesons are also used to calculate η/π0\eta/\pi^0 cross section ratios, which show evidence of a deviation from the world average. These studies offer new constraints on mass-dependent nuclear effects in heavy-ion collisions, as well as η\eta and η\eta' meson fragmentation.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://lhcbproject.web.cern.ch/Publications/p/LHCb-PAPER-2023-030.html (LHCb public pages

    A measurement of ΔΓs\Delta \Gamma_{s}

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    Using a dataset corresponding to 9 fb19~\mathrm{fb}^{-1} of integrated luminosity collected with the LHCb detector between 2011 and 2018 in proton-proton collisions, the decay-time distributions of the decay modes Bs0J/ψηB_s^0 \rightarrow J/\psi \eta' and Bs0J/ψπ+πB_s^0 \rightarrow J/\psi \pi^{+} \pi^{-} are studied. The decay-width difference between the light and heavy mass eigenstates of the Bs0B_s^0 meson is measured to be ΔΓs=0.087±0.012±0.009ps1\Delta \Gamma_s = 0.087 \pm 0.012 \pm 0.009 \, \mathrm{ps}^{-1}, where the first uncertainty is statistical and the second systematic.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-025.htm

    Observation of strangeness enhancement with charmed mesons in high-multiplicity pPbp\mathrm{Pb} collisions at sNN=8.16\sqrt {s_{\mathrm{NN}}}=8.16\,TeV

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    The production of prompt Ds+D^+_{s} and D+D^+ mesons is measured by the LHCb experiment in proton-lead (pPbp\mathrm{Pb}) collisions in both the forward (1.5<y<4.01.5<y^*<4.0) and backward (5.0<y<2.5-5.0<y^*<-2.5) rapidity regions at a nucleon-nucleon center-of-mass energy of sNN=8.16\sqrt {s_{\mathrm{NN}}}=8.16\,TeV. The nuclear modification factors of both Ds+D^+_{s} and D+D^+ mesons are determined as a function of transverse momentum, pTp_{\mathrm{T}}, and rapidity. In addition, the Ds+D^+_{s} to D+D^+ cross-section ratio is measured as a function of the charged particle multiplicity in the event. An enhanced Ds+D^+_{s} to D+D^+ production in high-multiplicity events is observed for the whole measured pTp_{\mathrm{T}} range, in particular at low pTp_{\mathrm{T}} and backward rapidity, where the significance exceeds six standard deviations. This constitutes the first observation of strangeness enhancement in charm quark hadronization in high-multiplicity pPbp\mathrm{Pb} collisions. The results are also qualitatively consistent with the presence of quark coalescence as an additional charm quark hadronization mechanism in high-multiplicity proton-lead collisions.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-021.html (LHCb public pages

    Measurement of associated J/ψJ/\psi-ψ(2S)\psi(2S) production cross-section in pppp collisions at s=13\sqrt{s}=13 TeV

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    The cross-section of associated J/ψJ/\psi-ψ(2S)\psi(2S) production in proton-proton collisions at a centre-of-mass energy of s=13\sqrt{s}=13 TeV is measured using a data sample corresponding to an integrated luminosity of 4.2 fb1^{-1}, collected by the LHCb experiment. The measurement is performed for both J/ψJ/\psi and ψ(2S)\psi(2S) mesons having transverse momentum pT<14p_{\text{T}}<14 GeV/cc and rapidity 2.0<y<4.52.0<y<4.5, assuming negligible polarisation of the J/ψJ/\psi and ψ(2S)\psi(2S) mesons. The production cross-section is measured to be 4.5±0.7±0.34.5\pm0.7\pm0.3 nb, where the first uncertainty is statistical and the second systematic. The differential cross-sections are measured as functions of several kinematic variables of the J/ψJ/\psi-ψ(2S)\psi(2S) candidates. The results are combined with a measurement of J/ψJ/\psi-J/ψJ/\psi production, giving a cross-section ratio between J/ψJ/\psi-ψ(2S)\psi(2S) and J/ψJ/\psi-J/ψJ/\psi production of 0.274±0.044±0.0080.274\pm0.044\pm0.008, where the first uncertainty is statistical and the second systematic.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2023-023.html (LHCb public pages

    Cardiopoietic cell therapy for advanced ischemic heart failure: results at 39 weeks of the prospective, randomized, double blind, sham-controlled CHART-1 clinical trial

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    Cardiopoietic cells, produced through cardiogenic conditioning of patients' mesenchymal stem cells, have shown preliminary efficacy. The Congestive Heart Failure Cardiopoietic Regenerative Therapy (CHART-1) trial aimed to validate cardiopoiesis-based biotherapy in a larger heart failure cohort

    Robust Dexterous Manipulation : A Methodology using Visual Servoing

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    This paper proposes a methodology called visual servoing for dexterous manipulation using dexterous hands 1 . Most of the literature on dexterous manipulation follows the classical &quot;planning then control&quot; scheme. A successful outcome is conditional on the perfectly planned fingers&apos; trajectories. Although tactile sensors have been improved, there are not accurate enough for the object&apos;s pose estimation. Visual servoing can be considered as an attractive solution to the problems described above. Nevertheless, from the stability point of view, the introduction of a camera inside the control loop could lead to an unstable response. Using a DAE (Differential Algebraic Equation) formulation we introduce all the system components. We analyzed some situations that can be efficiently carried out. Finally we conclude by providing a numerical example of a 2D dexterous manipulation guided by the camera information. 1 Introduction The procedure of grasping starts when a robot arm reaches the obj..
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