99 research outputs found

    Secondary to primary ratio and the continuous acceleration

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    A general formula for the sec/prim ratio, independently of any details of the propagation and acceleration model is presented. In the limit of equal fragmentation paths for primaries and secondaries, this ratio at a given momentum nucleon is proportional only to the mean path of the observed primaries at that moment. It is shown that it is unlikely to get a decreasing sec/prim ratio with energy if an acceleration process takes place during particle propagation in the interstellar medium (ISM)

    The primary energy estimation of inclined giant EAS

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    Determination of the primary energy by surface arrays (like AGASA) through estimators (instead of total size), taken as densities at 600 m from the shower axis, needs a special procedure for inclined cascades when the maximum is close to the array (less than 2-3 radiation lengths above). According to the cascade theory and the simulations with the CORSIKA code above 10 EeV the exponential function used for /rho(600)/rho^(600) conversion from inclined to vertical showers is no longer valid. As follows from simulations at energies near to 100 EeV, the density at 600 m for zenith angles 25-35 exceeds by 10% the vertical density, whereas it was assumed to be 30% lower in the previous treatments. Such treatments generate an artificial increase in the estimation of the primary cosmic ray energy. The primary spectrum reconstructed by an appropriate procedure for inclined showers confirms GZK prediction and eliminates the divergence between measurements at ultra-high energies

    EAS experiment on board of the Airbus A380

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    We consider taking the opportunity of about 10.000 hours of test of the Airbus A380, and to install at passenger space detectors for high energy cosmic ray events. The altitude of 10 km (250 g/cm 2 ) would give opportunity to measure EAS originating from heavy primaries to energies exceeding 10 7 GeV, and also coming without interaction proton component beyond the energy of the knee. At the altitude the iron originated EAS are well developed and registering their lateral distribution in 70 meters long cabin it is possible to distinguish them from proton originated EAS. Hadron component of EAS (registered as number of secondary hadrons produced in the detector) would help in discrimination and energy estimation. On another hand, registrations of high energy protons (without EAS) would enable to measure high energy proton spectrum. The energy of the proton would be estimated via hadron multiplicity in single interaction inside the detector. We propose to use about 60 modules of 0.5 m 2 of active detectors with scintillators to detect E-M component and carbon target with lead layer to detect the hadronic component via neutron registrations

    High energy cosmic rays in the low stratosphere and extrapolation above LHC energies

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    We review the data obtained with the emulsion chambers boarded on Concorde for the events collected above 106 GeV and their specific properties (large multiplicities, multiclusters, coplanar emission): the main features are compared to the expectation of our HDPM2 Monte Carlo collision generator. This multiproduction event generator has been adjusted and tuned, according to the pseudo-rapidity distributions recently observed at √s = 630 GeV, as well as to previous Fermi-lab results at √s = 1800 GeV: an increase of the total inelasticity (0.72 for NSD component) near the knee region and a more important violation than usually expected for Feynman’s scaling in forward region are observed. In such cirumstance, we have simulated large and giant air showers taking into account, in addition, new processes, such as diquark breaking, up to energies exceeding 1020 eV for P.AUGER and EUSO experiments

    Lateral distribution functions for giant air showers

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    We have compared the lateral analytical structure functions coming from cascade theory to the numerical distributions generated by EAS Monte Carlo simulations and to the empirical functions used in giant air showers experiments. Introducing the Gaussian hypergeometric formalism, we have improved the analytical description in the most common topological situations and we propose a new function characterized by both terms fitted separately to the electron-positron and the muon components. Important effects in the accuracy of the core position determination are underlined and consequences for the primary energy estimation are discussed. The consecutive treatment and interpretation of the data contained in the catalogues of Volcano Ranch and Yakutsk, completed by the most energetic event of AGASA, are presented. Results might have important implications for detector configuration of the future giant air shower arrays

    High energy hadrons in EAS at mountain altitude

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    An extensive simulation has been carried out to estimate the physical interpretation of dynamical factors such as , in terms of high energy interaction features, concentrated in the present analysis on the average transverse momentum. It appears that the large enhancement observed for versus primary energy, suggesting in earliest analysis a significant rise of with energy, is only the result of the limited resolution of the detectors and remains in agreement with a wide range of models used in simulations.Comment: 13 pages, 6 PostScript figures, LaTeX Subm. to JPhys

    Crowdsourcing hypothesis tests: Making transparent how design choices shape research results

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    To what extent are research results influenced by subjective decisions that scientists make as they design studies? Fifteen research teams independently designed studies to answer fiveoriginal research questions related to moral judgments, negotiations, and implicit cognition. Participants from two separate large samples (total N > 15,000) were then randomly assigned to complete one version of each study. Effect sizes varied dramatically across different sets of materials designed to test the same hypothesis: materials from different teams renderedstatistically significant effects in opposite directions for four out of five hypotheses, with the narrowest range in estimates being d = -0.37 to +0.26. Meta-analysis and a Bayesian perspective on the results revealed overall support for two hypotheses, and a lack of support for three hypotheses. Overall, practically none of the variability in effect sizes was attributable to the skill of the research team in designing materials, while considerable variability was attributable to the hypothesis being tested. In a forecasting survey, predictions of other scientists were significantly correlated with study results, both across and within hypotheses. Crowdsourced testing of research hypotheses helps reveal the true consistency of empirical support for a scientific claim.</div

    A global experiment on motivating social distancing during the COVID-19 pandemic

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    Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

    A multi-country test of brief reappraisal interventions on emotions during the COVID-19 pandemic

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    The COVID-19 pandemic has increased negative emotions and decreased positive emotions globally. Left unchecked, these emotional changes might have a wide array of adverse impacts. To reduce negative emotions and increase positive emotions, we tested the effectiveness of reappraisal, an emotion-regulation strategy that modifies how one thinks about a situation. Participants from 87 countries and regions (n = 21,644) were randomly assigned to one of two brief reappraisal interventions (reconstrual or repurposing) or one of two control conditions (active or passive). Results revealed that both reappraisal interventions (vesus both control conditions) consistently reduced negative emotions and increased positive emotions across different measures. Reconstrual and repurposing interventions had similar effects. Importantly, planned exploratory analyses indicated that reappraisal interventions did not reduce intentions to practice preventive health behaviours. The findings demonstrate the viability of creating scalable, low-cost interventions for use around the world

    A global experiment on motivating social distancing during the COVID-19 pandemic

    Get PDF
    Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e. a controlling message) compared to no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly-internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared to the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly-internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing: Controlled motivation was associated with more defiance and less long-term behavioral intentions to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges
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