519 research outputs found
Acute hematogenous osteomyelitis of long tubular and flat bones in children
The clinical-statistical analysis of treatment and diagnostics effectiveness of long tubular and flat bones osteomyelitis in 119 children older than 6 months has been carried out. Polymorphism of osteomyelitis clinical picture of pelvic bones, anatomical features of their location and structure create difficulties for early diagnostics and rational treatment. The method of choice in complex diagnostics was computed tomography, that allowed to establish topical diagnosis in the early stages in 52.9% of cases of pelvic bones osteomyelitis, degree of bone destruction and its prevalence, to determine the treatment policy. Operative intervention was required for 90.8% of patients in acute phase of hematogenous osteomyelitis.Проведен клинико-статистический анализ результативности диагностики и лечения остеомиелита длинных трубчатых и плоских костей у 119 детей старше 6 месяцев. Полиморфизм клинической картины остеомиелита костей таза, анатомические особенности их расположения и строения создают трудности для ранней диагностики и рационального лечения. Методом выбора в комплексной диагностике явилась компьютерная томография, что позволило в 52,9% случаев остеомиелита костей таза в ранние сроки установить топический диагноз, степень деструкции кости и её распространенность, определить лечебную тактику. В острую фазу гематогенного остеомиелита оперативное вмешательство требовалось 90,8% больных
The HADES Tracking System
The tracking system of the dielectron spectrometer HADES at GSI Darmstadt is
formed out of 24 low-mass, trapezoidal multi-layer drift chambers providing in
total about 30 square meter of active area. Low multiple scattering in the in
total four planes of drift chambers before and after the magnetic field is
ensured by using helium-based gas mixtures and aluminum cathode and field
wires. First in-beam performance results are contrasted with expectations from
simulations. Emphasis is placed on the energy loss information, exploring its
relevance regarding track recognition.Comment: 6 pages, 4 figures, presented at the 10th Vienna Conference on
Instrumentation, Vienna, February 2004, to be published in NIM A (special
issue
Recoil Polarization Measurements of the Proton Electromagnetic Form Factor Ratio to Q^2 = 8.5 GeV^2
Among the most fundamental observables of nucleon structure, electromagnetic
form factors are a crucial benchmark for modern calculations describing the
strong interaction dynamics of the nucleon's quark constituents; indeed, recent
proton data have attracted intense theoretical interest. In this letter, we
report new measurements of the proton electromagnetic form factor ratio using
the recoil polarization method, at momentum transfers Q2=5.2, 6.7, and 8.5
GeV2. By extending the range of Q2 for which GEp is accurately determined by
more than 50%, these measurements will provide significant constraints on
models of nucleon structure in the non-perturbative regime
Inclusive pion and eta production in p+Nb collisions at 3.5 GeV beam energy
Data on inclusive pion and eta production measured with the dielectron
spectrometer HADES in the reaction p+93Nb at a kinetic beam energy of 3.5 GeV
are presented. Our results, obtained with the photon conversion method,
supplement the rather sparse information on neutral meson production in
proton-nucleus reactions existing for this bombarding energy regime. The
reconstructed e+e-e+e- transverse-momentum and rapidity distributions are
confronted with transport model calculations, which account fairly well for
both pi0 and eta production.Comment: 12 pages, 9 figures, submitted to Physical Review
Searching a Dark Photon with HADES
We present a search for the e+e- decay of a hypothetical dark photon, also
names U vector boson, in inclusive dielectron spectra measured by HADES in the
p (3.5 GeV) + p, Nb reactions, as well as the Ar (1.756 GeV/u) + KCl reaction.
An upper limit on the kinetic mixing parameter squared epsilon^{2} at 90% CL
has been obtained for the mass range M(U) = 0.02 - 0.55 GeV/c2 and is compared
with the present world data set. For masses 0.03 - 0.1 GeV/c^2, the limit has
been lowered with respect to previous results, allowing now to exclude a large
part of the parameter region favoured by the muon g-2 anomaly. Furthermore, an
improved upper limit on the branching ratio of 2.3 * 10^{-6} has been set on
the helicity-suppressed direct decay of the eta meson, eta-> e+e-, at 90% CL
Medium effects in proton-induced production at 3.5 GeV
We present the analysis of the inclusive production in p+p and p+Nb
collisions measured with the HADES detector at a beam kinetic energy of 3.5
GeV. Data are compared to the GiBUU transport model. The data suggest the
presence of a repulsive momentum-dependent kaon potential as predicted by the
Chiral Perturbation Theory (ChPT). For the kaon at rest and at normal nuclear
density, the ChPT potential amounts to MeV. A detailed tuning of
the kaon production cross sections implemented in the model has been carried
out to reproduce the experimental data measured in p+p collisions. The
uncertainties in the parameters of the model were examined with respect to the
sensitivity of the experimental results from p+Nb collisions to the in-medium
kaon potential.Comment: 13 pages, 14 figure
An upper limit on hypertriton production in collisions of Ar(1.76 AGeV)+KCl
A high-statistic data sample of Ar(1.76 AGeV)+KCl events recorded with HADES
is used to search for a hypertriton signal. An upper production limit per
centrality-triggered event of x on the level is
derived. Comparing this value with the number of successfully reconstructed
hyperons allows to determine an upper limit on the ratio
, which is confronted with statistical and
coalescence-type model calculations
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