95 research outputs found
Search for an exotic S=-2, Q=-2 baryon resonance at a mass near 1862 MeV in quasi-real photoproduction
A search for an exotic baryon resonance with has been performed
in quasi-real photoproduction on a deuterium target through the decay channel
. No evidence for
a previously reported resonance is found in the invariant mass spectrum. An upper limit for the photoproduction cross
section of 2.1 nb is found at the 90% confidence level. The photoproduction
cross section for the is found to be between 9 and 24 nb
Evidence for a narrow |S|=1 baryon state at a mass of 1528 MeV in quasi-real photoproduction
Evidence for a narrow baryon state is found in quasi-real photoproduction on
a deuterium target through the decay channel p K^0_S --> p pi^+ pi^-. A peak is
observed in the p K^0_S invariant mass spectrum at 1528 +/- 2.6 (stat) +/-2.1
(syst) MeV. Depending on the background model,the naive statistical
significance of the peak is 4--6 standard deviations and its width may be
somewhat larger than the experimental resolution of sigma=4.3 -- 6.2 MeV. This
state may be interpreted as the predicted S=+1 exotic Theta^{+}(uuddbar(s))
pentaquark baryon. No signal for an hypothetical Theta^{++} baryon was observed
in the pK^+ invariant mass distribution. The absence of such a signal indicates
that an isotensor Theta is excluded and an isovector Theta is unlikely.Comment: 8 pages, 4 figure
DONOR-TRANSMITTED CORONARY ATHEROSCLEROSIS
Aim. To estimate opportunities, prospects and safety of using heart transplants from aged donors who are at high risk of coronary atherosclerosis.Materials and methods. Over the period from March 1987 to May 2014450 heart transplantations (HTx) were performed in V.I.Shumakov Federal Research Center of Transplantology and Artifi cial Organs. During the fi rst month after HTx coronarography was made to 152 (37,8%) recipients inorder to exclude/confi rm donor-transmitted coronary atherosclerosis (DTCA) and to identify tactics of treatment. Coronary atherosclerosis was detected among 16 patients (3,6% of total number of HTx), 15 (93,8%) men and 1 (6,2%) women. Mean age of recipients with DTCA at the moment of HTx was 48,3 ± 13,1 years.Results. Hemodynamically relevant coronary atherosclerosis was not detected and percutaneous coronary intervention (PCI) was not made in the group of patients with the mean age of 42,24 ± 8,91 years. Using heart transplants from aged donors is connected with increasing risk of DTCA among the recipients. DTCA-dependent PCI is not connected with coronary mortality. Actuarial survival rate of patients who underwent PCI is comparable with the same one in the total population of HTx recipients and is equal to 87,5% at 5 years and less.Conclusion. Hearts from aged donors (older than 50 years) may be used for HTx with suffi cient level of safety. Due to high level of DTCA using of hearts from such donors is preferable for completing urgent HTx to recipients 1А–В UNOS
THE FIRST EXPERIENCE IN CLINICAL APPLICATION OF DOMESTIC CIRCULATORY SUPPORT DEVICE ON BASIS OF IMPLANTABLE AXIAL PUMP FOR TWO STAGE HEART TRANSPLANTATION
The paper describes the first clinical experience in RF of successful application of domestic circulatory support device based on implantable axial pump for two stage heart transplantation. This case demonstrate the effec- tiveness and safety of our device (АВК-Н) for a longtime (270 days) left ventricular bypass and the ability to perform a successful transplantation of donor,s heart after application of this system
Flavor Decomposition of the Polarized Quark Distributions in the Nucleon from Inclusive and Semi-inclusive Deep-inelastic Scattering
Spin asymmetries of semi-inclusive cross sections for the production of
positively and negatively charged hadrons have been measured in deep-inelastic
scattering of polarized positrons on polarized hydrogen and 3He targets, in the
kinematic range 0.023<x<0.6 and 1 GeV^2<Q^2<10 GeV^2. Polarized quark
distributions are extracted as a function of x for up $(u+u_bar) and down
(d+d_bar) flavors. The up quark polarization is positive and the down quark
polarization is negative in the measured range. The polarization of the sea is
compatible with zero. The first moments of the polarized quark distributions
are presented. The isospin non-singlet combination Delta_q_3 is consistent with
the prediction based on the Bjorken sum rule. The moments of the polarized
quark distributions are compared to predictions based on SU(3)_f flavor
symmetry and to a prediction from lattice QCD.Comment: 14 pages, 6 figures (eps format), 10 tables in Latex New version
contains tables of asymmetries and correlation matri
The HERMES Polarized Hydrogen and Deuterium Gas Target in the HERA Electron Storage Ring
The HERMES hydrogen and deuterium nuclear-polarized gas targets have been in
use since 1996 with the polarized electron beam of HERA at DESY to study the
spin structure of the nucleon. Polarized atoms from a Stern-Gerlach Atomic Beam
Source are injected into a storage cell internal to the HERA electron ring.
Atoms diffusing from the center of the storage cell into a side tube are
analyzed to determine the atomic fraction and the atomic polarizations. The
atoms have a nuclear polarization, the axis of which is defined by an external
magnetic holding field. The holding field was longitudinal during 1996-2000,
and was changed to transverse in 2001. The design of the target is described,
the method for analyzing the target polarization is outlined, and the
performance of the target in the various running periods is presented
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