532 research outputs found

    Primary Particle Type of the Most Energetic Fly's Eye Air Shower

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    The longitudinal profile of the most energetic cosmic-ray air shower measured so far, the event recorded by the Fly's Eye detector with a reconstructed primary energy of about 320 EeV, is compared to simulated shower profiles. The calculations are performed with the CORSIKA code and include primary photons and different hadron primaries. For primary photons, preshower formation in the geomagnetic field is additionally treated in detail. For primary hadrons, the hadronic interaction models QGSJET01 and SIBYLL2.1 have been employed. The predicted longitudinal profiles are compared to the observation. A method for testing the hypothesis of a specific primary particle type against the measured profile is described which naturally takes shower fluctuations into account. The Fly's Eye event is compatible with any assumption of a hadron primary between proton and iron nuclei in both interaction models, although differences between QGSJET01 and SIBYLL2.1 in the predicted profiles of lighter nuclei exist. The primary photon profiles differ from the data on a level of ~1.5 sigma. Although not favoured by the observation, the primary photon hypothesis can not be rejected for this particular event.Comment: 20 pages, 8 figures; v2 matches version accepted by Astroparticle Physic

    Atmospheric Profiles at the Southern Pierre Auger Observatory and their Relevance to Air Shower Measurement

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    The dependence of atmospheric conditions on altitude and time have to be known at the site of an air shower experiment for accurate reconstruction of extensive air showers and their simulations. The height-profile of atmospheric depth is of particular interest as it enters directly into the reconstruction of longitudinal shower development and of the primary energy and mass of cosmic rays. For the southern part of the Auger Observatory, the atmosphere has been investigated in a number of campaigns with meteorological radio soundings and with continuous measurements of ground-based weather stations. Focussing on atmospheric depth and temperature profiles, temporal variations are described and monthly profiles are developed. Uncertainties of the monthly atmospheres that are currently applied in the Auger reconstruction are discussed.Comment: To be published in Proceedings of 29th International Cosmic Ray Conference (ICRC) 2005, Pune, Indi

    Views and experiences of managing eczema:systematic review and thematic synthesis of qualitative studies*

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    Background: The number of qualitative studies on eczema has increased rapidly in recent years. Systematically reviewing these can provide greater understandings of people’s perceptions of eczema and eczema treatments. Objectives: We sought to systematically review and thematically synthesize qualitative studies exploring views and experiences of people with eczema and parents/carers of children with eczema. Methods: We searched MEDLINE, EMBASE, PsycINFO and CINAHL from the earliest date available to February 2019. We selected papers focusing on views and experiences of eczema and eczema treatments, and barriers/facilitators to eczema self-management. We excluded papers focusing on health service provision models or health professionals’ views. Results: We synthesized 39 papers (reporting 32 studies) from 13 countries. We developed four analytical themes: (1) Eczema not viewed as a long-term condition; (2) Significant psychosocial impact not acknowledged by others; (3) Hesitancy (patient/carer uncertainty) about eczema treatments; and (4) Insufficient information and advice. Our findings suggest that people with eczema and their carers experience frustration at having to manage a condition that is often seen by others as mundane but has significant psychosocial impact and is difficult to manage due to concerns about, and burden of, treatment. This frustration can be exacerbated by experiences of conflicting and/or insufficient information and advice from health professionals, family and others. Conclusions: Effective self-management of eczema could be supported by addressing beliefs and concerns about treatments; seeking positive ways to promote a ‘control not cure’ message; acknowledging psychosocial impacts of eczema and treatment burden; and providing clear consistent advice or signposting towards reliable information.</p

    Searching for New Physics Through AMO Precision Measurements

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    We briefly review recent experiments in atomic, molecular, and optical physics using precision measurements to search for physics beyond the Standard Model. We consider three main categories of experiments: searches for changes in fundamental constants, measurements of the anomalous magnetic moment of the electron, and searches for an electric dipole moment of the electron.Comment: Prepared for Comments on AMO Physics at Physica Script

    Cross Section Limits for the 208^{208}Pb(86^{86}Kr,n)293^{293}118 Reaction

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    In April-May, 2001, the previously reported experiment to synthesize element 118 using the 208^{208}Pb(86^{86}Kr,n)293^{293}118 reaction was repeated. No events corresponding to the synthesis of element 118 were observed with a total beam dose of 2.6 x 1018^{18} ions. The simple upper limit cross sections (1 event) were 0.9 and 0.6 pb for evaporation residue magnetic rigidities of 2.00 TmT m and 2.12 TmT m, respectively. A more detailed cross section calculation, accounting for an assumed narrow excitation function, the energy loss of the beam in traversing the target and the uncertainty in the magnetic rigidity of the Z=118 recoils is also presented. Re-analysis of the primary data files from the 1999 experiment showed the reported element 118 events are not in the original data. The current results put constraints on the production cross section for synthesis of very heavy nuclei in cold fusion reactions.Comment: 7 pages, 2 figures. Submitted to EPJ
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