945 research outputs found
New data on direct ion storage dosemeters
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 âlong-term' linear response behaviour, the calibration and readout accuracy with large samples of âused' 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
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 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
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
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 86â102.4), 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 55â75% of the maximum possible index. Conclusions: Severe GERD causes substantial reductions in the patientâs 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 patientâs condition in various dimensions
Quality of life in benign colorectal diseaseâa review of the assessment with the Gastrointestinal Quality of Life Index (GIQLI)
Background and purpose The Gastrointestinal Quality of Life Index (GIQLI) is an instrument for the assessment of qualâ
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 29â74.7). The median GIQLI of all studies concerning benign colorectal
disease was 88 index points (range 56.2â113). 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 patientâs QOL, well documented by GIQLI, which
allows a comparison QOL with other published cohorts
Fragment Formation in Central Heavy Ion Collisions at Relativistic Energies
We perform a systematic study of the fragmentation path of excited nuclear
matter in central heavy ion collisions at the intermediate energy of . The theoretical calculations are based on a Relativistic
Boltzmann-Uehling-Uhlenbeck () transport equation including stochastic
effects. A Relativistic Mean Field () 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
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
of the high density phase of the nuclear Equation of State ().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
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 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
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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