486 research outputs found

    Coherent production on nuclei and measurements of total cross sections for unstable particles

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    The Kölbig–Margolis formula is fitted to some explicitly nonperturbative models of diffractive production. It is shown that, in spite of the fact that the standard procedure of fitting the integrated cross sections may give acceptable fits, thus obtained "cross sections of unstable particles", σ2\sigma_{2}, grossly disagree with the "true" cross sections known exactly from the models

    Spatial distribution and reduction of PCDD/PCDF Toxic Equivalents along three shallow lowland reservoirs

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    Reservoirs situated along a river continuum are ecosystems where rates of transfer of suspended matter and associated micropollutants are reduced due to sedimentation, accumulation, and biological and physical transformation processes. Among the micropollutants, PCDDs and PCDFs are substances that are highly toxic and carcinogenic for humans and animals. They are emitted and dispersed in the environment throughout the whole catchment area and may accumulate in aquatic and terrestrial food chains, creating a risk for human health. A wealth of data exists indicating the increase in the concentrations of pollutants along a river continuum. A comparative analysis of total, individual, and TEQ PCDD/PCDF concentrations in large lowland, shallow reservoirs located in different catchments (“I”—industrial/urban/ agricultural, “U”—urban/agricultural, and “A”—agricultural/ rural) showed decreases of the TEQ concentrations in bottom sediments along a gradient from the middle sections to the dam walls. Moreover, penta-, hexa-, and heptachlorinated CDD/CDF congeners were reduced from 28.8 up to 93.6 % in all three types of reservoirs. A further analysis of water samples from the inlets and outlets of the “A” reservoir confirmed this tendency.The authors wish to express their sincere appreciation to Prof. Konrad Rydzyński from the Nofer Institute of Occupational Medicine in Lodz, Prof. Richard Robarts from the UNEP Global Environment Monitoring System (GEMS)/Water Programme, Prof. Paul DuBowy from the U.S. Army Corps of Engineers, and Prof. David Harper from the Department of Biology, the University of Leicester for their constructive comments on an earlier version of this paper. The authors also wish to acknowledge the research team of the Nofer Institute of Occupational Medicine in Lodz: Dr Danuta Ligocka and Dr Wiktor Wesołowski for their assistance during the laboratory processes. The research was supported by the following projects of the Polish Ministry of Science and Higher Education: – N N305 365738 “Analysis of point sources pollution of nutrients, dioxins and dioxin-like compounds in the Pilica River catchment and draw up of reclamation methods”; – 2PO4 G08830 “Accumulation of dioxins and dioxin-like pollutants in the food chain of the Sulejowski and Włocławski Reservoirs: chemometric analysis and toxicological estimation”

    Tell Me How You Feel: Designing Emotion-Aware Voicebots to Ease Pandemic Anxiety In Aging Citizens

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    The feeling of anxiety and loneliness among aging population has been recently amplified by the COVID-19 related lockdowns. Emotion-aware multimodal bot application combining voice and visual interface was developed to address the problem in the group of older citizens. The application is novel as it combines three main modules: information, emotion selection and psychological intervention, with the aim of improving human well-being. The preliminary study with target group confirmed that multimodality improves usability and that the information module is essential for participating in a psychological intervention. The solution is universal and can also be applied to areas not directly related to COVID-19 pandemic.Comment: 16 page

    Determination of the total width of the eta' meson

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    Taking advantage of both the low-emittance proton-beam of the Cooler Synchrotron COSY and the high momentum precision of the COSY-11 detector system, the mass distribution of the eta' meson was measured with a resolution of 0.33 MeV/c^2 (FWHM), improving the experimental mass resolution by almost an order of magnitude with respect to previous results. Based on the sample of more than 2300 reconstructed pp --> pp eta' events the total width of the eta' meson was determined to be 0.226 +- 0.017(stat.) +- 0.014(syst.) MeV/c^2.Comment: 4 pages, 4 figure

    Measurement of the invariant mass distributions for the pp -> ppeta' reaction at excess energy of Q = 16.4 MeV

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    The proton-proton and proton-eta' invariant mass distributions have been determined for the pp -> ppeta' reaction at an excess energy of Q = 16.4 MeV. The measurement was carried out using the COSY-11 detector setup and the proton beam of the cooler synchrotron COSY. The shapes of the determined invariant mass distributions are similar to those of the pp -> ppeta reaction and reveal an enhancement for large relative proton-proton momenta. This result, together with the fact that the proton-eta interaction is much stronger that the proton-eta' interaction, excludes the hypothesis that the observed enhancement is caused by the interaction between the proton and the meson

    System Response Kernel Calculation for List-mode Reconstruction in Strip PET Detector

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    Reconstruction of the image in Positron Emission Tomographs (PET) requires the knowledge of the system response kernel which describes the contribution of each pixel (voxel) to each tube of response (TOR). This is especially important in list-mode reconstruction systems, where an efficient analytical approximation of such function is required. In this contribution, we present a derivation of the system response kernel for a novel 2D strip PET.Comment: 10 pages, 2 figures; Presented at Symposium on applied nuclear physics and innovative technologies, Cracow, 03-06 June 201

    Isospin dependence of the eta prime meson production in nucleon-nucleon collisions

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    A comparison of the close-to-threshold total cross section for the eta prime production in pp --> pp eta prime and pn --> pn eta prime reactions constitutes a tool to investigate the eta prime meson structure and the reaction mechanism in the channels of isospin I=0 and I=1 and may provide insight into the flavour-singlet (perhaps also into gluonium) content of the eta prime meson. In this contribution we present preliminary results of measurement of the quasi-free production of the eta prime meson in the proton-neutron collisions conducted using the COSY-11 facility.Comment: Presented at 10th International Workshop on Meson Production, Properties and Interaction (MESON 2008), Cracow, Poland, 6 - 10 June 200
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