945 research outputs found

    New data on direct ion storage dosemeters

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    The DIS-1 dosemeter from the Finnish company RADOS is an innovative kind of passive electronic dosemeter for photon and beta radiation. This study examines the ‘long-term' linear response behaviour, the calibration and readout accuracy with large samples of ‘used' DIS-1 dosemeters especially in the low-dose region, which is of special interest for radiation protection issues. Our measurements prove the adequacy of the DIS-1 dosemeter for long-term-personal dosimetry. The fast and precise readout seems to make the DIS-1 dosemeter an ideal choice for personal dosimetry in low-dose environment

    Nuclear stopping and flow in heavy ion collisions and the in-medium NN cross section

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    We present transport calculations for heavy ion reactions in which the mean field and the in-medium nucleon-nucleon cross section are consistently based on the same effective interaction, i.e. the in-medium T-matrix from microscopic Dirac-Brueckner calculations. Doing so, the stopping in central reactions in terms of the recently proposed vartlvar_{\rm tl} observable and the correlation to the behavior of the directed flow is investigated. The relation to the nuclear shear viscosity is discussed.Comment: 9 pages, 4 figure

    Asymmetric Colliding Nuclear Matter Approach in Heavy Ion Collisions

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    The early stage of a heavy ion collision is governed by local non-equilibrium momentum distributions which have been approximated by colliding nuclear matter configurations, i.e. by two Lorentz elongated Fermi ellipsoids. This approach has been extended from the previous assumption of symmetric systems to asymmetric 2-Fermi sphere configurations, i.e. to different densities. This provides a smoother transition from the limiting situation of two interpenetrating currents to an equilibrated system. The model is applied to the dynamical situations of heavy ion collisions at intermediate energies within the framework of relativistic transport (RBUU) calculations. We find that the extended colliding nuclear matter approach is more appropriate to describe collective reaction dynamics in terms of flow observables, in particular, for the elliptic flow at low energies.Comment: 21 pages, 8 figures, accepted for publication in Nuclear Physics

    Gastrointestinal Quality of Life in Gastroesophageal Reflux Disease: A Systematic Review

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    Background: The Gastrointestinal Quality of Life Index (GIQLI) is a well-established instrument for the assessment of quality of life (QOL) in gastrointestinal (GI) diseases. The purpose of this literature review was to investigate QOL by means of GIQLI in patients with gastroesophageal reflux disease (GERD) prior to any interventional therapy. There are several reports on GIQLI data; however, comparisons from different countries and/or different GERD cohorts assessing the same disease have to date not been conducted. Methods: The GIQLI uses 36 items around 5 dimensions (GI symptoms [19 items], emotional dimension [5 items], physical dimension [7 items], social dimension [4 items], and therapeutic influences [1 item]). A literature search was conducted on the application of GIQLI in GERD patients prior to interventional therapy using reports in PubMed. Data on the mean GIQLI as well as index data for the 5 dimensions as originally validated were extracted from the published patient cohorts. A comparison with the normal healthy control group from the original publication of the GIQLI validation conducted by Eypasch was performed. Data are presented descriptively as GIQLI points as well as a reduction from 100% maximum possible index points (max 144 index points = highest QOL). Results: In total, 77 abstracts from studies using the GIQLI on patients with GERD were identified. After screening for content, 21 publications were considered for further analysis. Ten studies in GERD patients comprised complete calculations of all dimensions and were included in the analysis. Data from 1,682 study patients were evaluated with sample sizes ranging from 33 to 568 patients (median age of 789 females and 858 males: 51.8 years). The median overall GIQLI for the patient group was 91.7 (range 86–102.4), corresponding to 63.68% of the maximum GIQLI. The dimensions with the largest deviation from the respective maximum score were the physical dimension (55% of maximum) followed by the emotional dimension (60% of maximum). In summary, the GIQLI level in GERD cohorts was reduced to 55–75% of the maximum possible index. Conclusions: Severe GERD causes substantial reductions in the patient’s QOL. The level of GIQLI can carry between different studied GERD cohorts from different departments and countries. GIQLI can be used as an established tool to assess the patient’s condition in various dimensions

    Quality of life in benign colorectal disease—a review of the assessment with the Gastrointestinal Quality of Life Index (GIQLI)

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    Background and purpose The Gastrointestinal Quality of Life Index (GIQLI) is an instrument for the assessment of qual‑ ity of life (QOL) in diseases of the upper and lower GI tract, which is validated in several languages around the world. The purpose of this literature review is the assessment of the GIQLI in patients with benign colorectal diseases. Reports on GIQLI data are collected from several institutions, countries, and different cultures which allows for comparisons, which are lacking in literature. Methods The GIQL Index uses 36 items around 5 dimensions (gastrointestinal symptoms (19 items), emotional dimension (5 items), physical dimension (7 items), social dimension (4 items), and therapeutic influences (1 item). The literature search was performed on the GIQLI and colorectal disease, using reports in PubMed. Data are presented descriptively as GIQL Index points as well as a reduction from 100% maximum possible index points (max 144 index points=highest quality of life). Results The GIQLI was found in 122 reports concerning benign colorectal diseases, of which 27 were finally selected for detailed analysis. From these 27 studies, information on 5664 patients (4046 female versus 1178 male) was recorded and summarized. The median age was 52 years (range 29–74.7). The median GIQLI of all studies concerning benign colorectal disease was 88 index points (range 56.2–113). Benign colorectal disease causes a severe reduction in QOL for patients down to 61% of the maximum. Conclusions Benign colorectal diseases cause substantial reductions in the patient’s QOL, well documented by GIQLI, which allows a comparison QOL with other published cohorts

    Fragment Formation in Central Heavy Ion Collisions at Relativistic Energies

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    We perform a systematic study of the fragmentation path of excited nuclear matter in central heavy ion collisions at the intermediate energy of 0.4AGeV0.4 AGeV. The theoretical calculations are based on a Relativistic Boltzmann-Uehling-Uhlenbeck (RBUURBUU) transport equation including stochastic effects. A Relativistic Mean Field (RMFRMF) approach is used, based on a non-linear Lagrangian, with coupling constants tuned to reproduce the high density results of calculations with correlations. At variance with the case at Fermi energies, a new fast clusterization mechanism is revealed in the early compression stage of the reaction dynamics. Fragments appear directly produced from phase-space fluctuations due to two-body correlations. In-medium effects of the elastic nucleon-nucleon cross sections on the fragmentation dynamics are particularly discussed. The subsequent evolution of the primordial clusters is treated using a simple phenomenological phase space coalescence algorithm. The reliability of the approach, formation and recognition, is investigated in detail by comparing fragment momentum space distributions {\it and simultaneously} their yields with recent experimental data of the FOPIFOPI collaboration by varying the system size of the colliding system, i.e. its compressional energy (pressure, radial flow). We find an excellent agreement between theory and experiment in almost all the cases and, on the other hand, some limitations of the simple coalescence model. Furthermore, the temporal evolution of the fragment structure is explored with a clear evidence of an earlier formation of the heavier clusters, that will appear as interesting relicsrelics of the high density phase of the nuclear Equation of State (EoSEoS).Comment: 21 pages, 8 figures, Latex Elsart Style, minor corrections in p.7, two refs. added, Nucl.Phys.A, accepte

    Isospin Effects on Strangeness in Heavy-Ion Collisions

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    Kaon properties are studied within the framework of a fully covariant transport approach. The kaon-nucleon potential is evaluated in two schemes, a chiral perturbative approach and an effective One-Boson-Exchange model. Isospin effects are explicitly accounted for in both models. The transport calculations indicate a significant sensitivity of momentum distributions and total yields of K0,+K^{0,+} isospin states on the choice of the kaon-nucleon interaction. Furthermore, isospin effects are rather moderate on absolute kaon yields, but appear on strangeness ratios. This is an important issue in determining the high density symmetry energy from studies of strangeness production in heavy-ion collisions.Comment: 15 papes, 5 figures. Accepted for publication in Nuclear Physic

    On fundamental domains and volumes of hyperbolic Coxeter-Weyl groups

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    We present a simple method for determining the shape of fundamental domains of generalized modular groups related to Weyl groups of hyperbolic Kac-Moody algebras. These domains are given as subsets of certain generalized upper half planes, on which the Weyl groups act via generalized modular transformations. Our construction only requires the Cartan matrix of the underlying finite-dimensional Lie algebra and the associated Coxeter labels as input information. We present a simple formula for determining the volume of these fundamental domains. This allows us to re-produce in a simple manner the known values for these volumes previously obtained by other methods.Comment: v2: to be published in Lett Math Phys (reference added, typo corrected
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