75 research outputs found

    Update on the Combined Analysis of Muon Measurements from Nine Air Shower Experiments

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    Over the last two decades, various experiments have measured muon densities in extensive air showers over several orders of magnitude in primary energy. While some experiments observed differences in the muon densities between simulated and experimentally measured air showers, others reported no discrepancies. We will present an update of the meta-analysis of muon measurements from nine air shower experiments, covering shower energies between a few PeV and tens of EeV and muon threshold energies from a few 100 MeV to about 10GeV. In order to compare measurements from different experiments, their energy scale was cross-calibrated and the experimental data has been compared using a universal reference scale based on air shower simulations. Above 10 PeV, we find a muon excess with respect to simulations for all hadronic interaction models, which is increasing with shower energy. For EPOS-LHC and QGSJet-II.04 the significance of the slope of the increase is analyzed in detail under different assumptions of the individual experimental uncertainties

    A Combined Fit of the Diffuse Neutrino Spectrum using IceCube Muon Tracks and Cascades

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    The IceCube Neutrino Observatory first observed a diffuse flux of high energy astrophysical neutrinos in 2013. Since then, this observation has been confirmed in multiple detection channels such as high energy starting events, cascades, and through-going muon tracks. Combining these event selections into a high statistics global fit of 10 years of IceCube’s neutrino data could strongly improve the understanding of the diffuse astrophysical neutrino flux: challenging or confirming the simple unbroken power-law flux model as well as the astrophysical neutrino flux composition. One key component of such a combined analysis is the consistent modelling of systematic uncertainties of different event selections. This can be achieved using the novel SnowStorm Monte Carlo method which allows constraints to be placed on multiple systematic parameters from a single simulation set. We will report on the status of a new combined analysis of through-going muon tracks and cascades. It is based on a consistent all flavor neutrino signal and background simulation using, for the first time, the SnowStorm method to analyze IceCube’s high-energy neutrino data. Estimated sensitivities for the energy spectrum of the diffuse astrophysical neutrino flux will be shown

    Searching for VHE gamma-ray emission associated with IceCube neutrino alerts using FACT, H.E.S.S., MAGIC, and VERITAS

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    The realtime follow-up of neutrino events is a promising approach to searchfor astrophysical neutrino sources. It has so far provided compelling evidencefor a neutrino point source: the flaring gamma-ray blazar TXS 0506+056 observedin coincidence with the high-energy neutrino IceCube-170922A detected byIceCube. The detection of very-high-energy gamma rays (VHE, E>100GeV\mathrm{E} >100\,\mathrm{GeV}) from this source helped establish the coincidence andconstrained the modeling of the blazar emission at the time of the IceCubeevent. The four major imaging atmospheric Cherenkov telescope arrays (IACTs) -FACT, H.E.S.S., MAGIC, and VERITAS - operate an active follow-up program oftarget-of-opportunity observations of neutrino alerts sent by IceCube. Thisprogram has two main components. One are the observations of known gamma-raysources around which a cluster of candidate neutrino events has been identifiedby IceCube (Gamma-ray Follow-Up, GFU). Second one is the follow-up of singlehigh-energy neutrino candidate events of potential astrophysical origin such asIceCube-170922A. GFU has been recently upgraded by IceCube in collaborationwith the IACT groups. We present here recent results from the IACT follow-upprograms of IceCube neutrino alerts and a description of the upgraded IceCubeGFU system.<br

    Changes and trends of climate elements and indices in the region of Mediterranean Croatia

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    Climate is complex ecological factor described by different climate elements and phenomena that effect development of vegetation and its natural distribution. Climate elements the most important for vegetation are air temperatures, amount of precipitations, air humidity and wind. The aim of this research was to determine trends and changes of climate elements in the region of Mediterranean Croatia. Meteorological stations with the longest monitoring period in the region of the Mediterranean Croatia were chosen in order to determine trends of the climate elements. Decreasing or increasing trends of individual climate elements and indices were analysed using linear trend of regression analysis. Climate elements and indices of the referent line were compared with period between 1991 and 2010. At all meteorological stations was found negative trend of annual amount of precipitations and Lang ´s rain factor. Exception was meteorological station Rijeka with increase of annual amount of precipitations and Lang ´s rain factor. Trends of air temperatures at all meteorological stations were positive. Values of Lang ´s rain factor in the researched region are decreasing resulting higher aridity of the region. Trends of potential evapotranspiration are significant and positive at all meteorological stations. Changes of air temperatures are more noticeable than those of precipitations, while changes of potential evapotranspiration are more noticeable than those of Lang ´s rain factor. Forest vegetation and crop plants of Mediterranean Croatia are adapted to certain climate conditions predominating in this region. This conditions change through time effecting growth and development of all organisms

    American College of Cardiology (ACC)’s PINNACLE India Quality Improvement Program (PIQIP)—Inception, progress and future direction: A report from the PIQIP Investigators

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    Cardiovascular diseases have surpassed infectious disorders to become the leading cause of morbidity and mortality in India.1 A national-level registry comprehensively documenting the current-day prevalence of cardiovascular risk factors and disease burden among patients seeking care in the outpatient setting in India is currently non-existent. With a burgeoning urban population, the cardiovascular disease burden in India is set to skyrocket, with an estimated 18 million productive years of life lost by 2030.2 While there are limited quality improvement registries in India, for example, the Kerala acute coronary syndrome and Trivandrum heart failure registries, their focus is on in-patient care quality improvement, while the vast majority of patients with cardiovascular diseases worldwide, including India, interact with the health care system in the outpatient setting.3,4 Recognizing this unmet need, the American College of Cardiology partnered with local stakeholders in India to establish India's first outpatient cardiovascular disease performance measurement initiative in 2011, the PINNACLE (Practice Innovation and Clinical Excellence) India Quality Improvement Program (PIQIP).5 This manuscript discusses the inception of the PIQIP registry, the progress it has made and challenges thus far, and its future direction and the promise it holds for cardiovascular care quality improvement in India

    American College of Cardiology (ACC)\u27s PINNACLE India quality improvement program (PIQIP)-Inception, progress and future direction: A report from the PIQIP Investigators

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    Cardiovascular diseases have surpassed infectious disorders to become the leading cause of morbidity and mortality in India.1 A national-level registry comprehensively documenting the current-day prevalence of cardiovascular risk factors and disease burden among patients seeking care in the outpatient setting in India is currently non-existent. With a burgeoning urban population, the cardiovascular disease burden in India is set to skyrocket, with an estimated 18 million productive years of life lost by 2030.2 While there are limited quality improvement registries in India, for example, the Kerala acute coronary syndrome and Trivandrum heart failure registries, their focus is on in-patient care quality improvement, while the vast majority of patients with cardiovascular diseases worldwide, including India, interact with the health care system in the outpatient setting.3,4 Recognizing this unmet need, the American College of Cardiology partnered with local stakeholders in India to establish India\u27s first outpatient cardiovascular disease performance measurement initiative in 2011, the PINNACLE (Practice Innovation and Clinical Excellence) India Quality Improvement Program (PIQIP).5 This manuscript discusses the inception of the PIQIP registry, the progress it has made and challenges thus far, and its future direction and the promise it holds for cardiovascular care quality improvement in India
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