86 research outputs found

    Стриктуры желчных путей при описторхозе

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    1170 patients with chronic opisthorchosis have been operated by surgeons of Tomsk hepatology center for 35 years, 4756 patients have been treated. In 730 operated patients different strictures of biliary tracts have been revealed, strictures of cystic duct have been observed in 372 patients (51%), strictures of choledoch distal section and major duodenal papilla (MDP) of expanded character — in 124 patients (17%), stricture combination — in 205 patients (28%) and sclerosing cholangitis — in 29 (4%). The treatment of opisthorchosis strictures of biliary tracts is surgical. In case of any its localization a cholecystectomy is necessary, in case of strictures of choledoch distal section and MDP a supraduodenal choledochoduodenostomy is necessary. In early postsurgical period it is prescribed an anthelmintic therapy with iodinol through external drainage of bile ducts. Good farther results have been marked at 79,4% of patients.За 35 лет работы сотрудниками Томского гепатологического центра были пролечены 4 756 больных с хроническим описторхозом, из них оперированы — 1 170. У 730 оперированных пациентов выявлены различные стриктуры билиарного тракта, в том числе стриктуры пузырного протока наблюдались у 372 человек (51%), стриктуры дистального отдела холедоха и большого дуоденального сосочка (БДС), носящие протяженный характер, — у 124 (17%), сочетание стриктур — у 205 (28%), склерозирующий холангит — у 29 (4%). Лечение описторхозных стриктур желчных путей — оперативное. При всех локализациях стриктур необходима холецистэктомия, при стриктурах дистального отдела холедоха и БДС — супрадуоденальная холедоходуоденостомия. В раннем послеоперационном периоде показана антигельминтная терапия йодинолом через наружный дренаж желчных протоков. Хорошие отдаленные результаты отмечены у 79,4% больных

    Печеночная недостаточность при механическом холестазе паразитарного генеза

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    In Tomsk zonal hepatologic center 358 patients with obstructive parasitogenic jaundice have been operated (alveococcosis-based — 43, echinococcosis-based — 17, opisthorchosis-based — 298). Clinical presentations of hepatic failure before the surgery have been observed at 30,7% of patients, more often — under long and intensive cholestasis. Postsurgical hepatic failure has developed at 23,1%. Intraportal medicine infusions play an important role in prophylaxis and treatment of hepatic failure along with timely and optimal surgery. Infusions permit to decrease the hepatic failure progress probability from 60,6 to 30,5%, probability of suppurative complications from 10,3 to 3,1% and postsurgical lethality from 38,2 to 9,5%.В Томском зональном гепатологическом центре оперировано по поводу механической желтухи паразитарного генеза 358 человек (на почве альвеококкоза — 43, эхинококкоза — 17, описторхоза — 298). Клинические проявления печеночной недостаточности до операции наблюдались у 30,7% пациентов, чаще при длительном и интенсивном холестазе. Послеоперационная недостаточность печени развилась у 23,2%. В профилактике и лечении печеночной недостаточности наряду со своевременностью и оптимальностью оперативного вмешательства важную роль играют внутрипортальные инфузии лекарственных средств, позволяющие снизить вероятность прогрессирования недостаточности печени с 60,6 до 30,5%, развития гнойных осложнений с 10,3 до 3,1%, уменьшить послеоперационную летальность с 38,2 до 9,5%

    Longitudinal double spin asymmetries in single hadron quasi-real photoproduction at high pTp_T

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    We measured the longitudinal double spin asymmetries ALLA_{LL} for single hadron muo-production off protons and deuterons at photon virtuality Q2Q^2 < 1(GeV/c\it c)2^2 for transverse hadron momenta pTp_T in the range 0.7 GeV/c\it c to 4 GeV/c\it c . They were determined using COMPASS data taken with a polarised muon beam of 160 GeV/c\it c or 200 GeV/c\it c impinging on polarised 6LiD\mathrm{{}^6LiD} or NH3\mathrm{NH_3} targets. The experimental asymmetries are compared to next-to-leading order pQCD calculations, and are sensitive to the gluon polarisation ΔG\Delta G inside the nucleon in the range of the nucleon momentum fraction carried by gluons 0.05<xg<0.20.05 < x_g < 0.2

    Interplay among transversity induced asymmetries in hadron leptoproduction

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    In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows to establish quantitative relationships among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.Comment: 6 figure

    Interplay among transversity induced asymmetries in hadron leptoproduction

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    In the fragmentation of a transversely polarized quark several left-right asymmetries are possible for the hadrons in the jet. When only one unpolarized hadron is selected, it exhibits an azimuthal modulation known as Collins effect. When a pair of oppositely charged hadrons is observed, three asymmetries can be considered, a di-hadron asymmetry and two single hadron asymmetries. In lepton deep inelastic scattering on transversely polarized nucleons all these asymmetries are coupled with the transversity distribution. From the high statistics COMPASS data on oppositely charged hadron-pair production we have investigated for the first time the dependence of these three asymmetries on the difference of the azimuthal angles of the two hadrons. The similarity of transversity induced single and di-hadron asymmetries is discussed. A new analysis of the data allows to establish quantitative relationships among them, providing for the first time strong experimental indication that the underlying fragmentation mechanisms are all driven by a common physical process.Comment: 6 figure

    Resonance Production and ππ\pi\pi S-wave in π+pπππ++precoil\pi^- + p \rightarrow \pi^- \pi^- \pi^+ + p_{recoil} at 190 GeV/c

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    The COMPASS collaboration has collected the currently largest data set on diffractively produced πππ+\pi^-\pi^-\pi^+ final states using a negative pion beam of 190 GeV/c momentum impinging on a stationary proton target. This data set allows for a systematic partial-wave analysis in 100 bins of three-pion mass, 0.5<m3π<2.50.5 < m_{3\pi} < 2.5 GeV/c2^2 , and in 11 bins of the reduced four-momentum transfer squared, 0.1<t<1.00.1 < t < 1.0 (GeV/c)2^2 . This two-dimensional analysis offers sensitivity to genuine one-step resonance production, i.e. the production of a state followed by its decay, as well as to more complex dynamical effects in nonresonant 3π3\pi production. In this paper, we present detailed studies on selected 3π3\pi partial waves with JPC=0+J^{PC} = 0^{-+}, 1++1^{++}, 2+2^{-+}, 2++2^{++}, and 4++4^{++}. In these waves, we observe the well-known ground-state mesons as well as a new narrow axial-vector meson a1(1420)a_1(1420) decaying into f0(980)πf_0(980) \pi. In addition, we present the results of a novel method to extract the amplitude of the ππ+\pi^-\pi^+ subsystem with IGJPC=0+0++I^{G}J^{PC} = 0^+ 0^{++} in various partial waves from the πππ+\pi^-\pi^-\pi^+ data. Evidence is found for correlation of the f0(980)f_0(980) and f0(1500)f_0(1500) appearing as intermediate ππ+\pi^- \pi^+ isobars in the decay of the known π(1800)\pi(1800) and π2(1880)\pi_2(1880).Comment: 96 page

    The Spin Structure Function g1pg_1^{\rm p} of the Proton and a Test of the Bjorken Sum Rule

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    New results for the double spin asymmetry A1pA_1^{\rm p} and the proton longitudinal spin structure function g1pg_1^{\rm p} are presented. They were obtained by the COMPASS collaboration using polarised 200 GeV muons scattered off a longitudinally polarised NH3_3 target. The data were collected in 2011 and complement those recorded in 2007 at 160\,GeV, in particular at lower values of xx. They improve the statistical precision of g1p(x)g_1^{\rm p}(x) by about a factor of two in the region x0.02x\lesssim 0.02. A next-to-leading order QCD fit to the g1g_1 world data is performed. It leads to a new determination of the quark spin contribution to the nucleon spin, ΔΣ\Delta \Sigma ranging from 0.26 to 0.36, and to a re-evaluation of the first moment of g1pg_1^{\rm p}. The uncertainty of ΔΣ\Delta \Sigma is mostly due to the large uncertainty in the present determinations of the gluon helicity distribution. A new evaluation of the Bjorken sum rule based on the COMPASS results for the non-singlet structure function g1NS(x,Q2)g_1^{\rm NS}(x,Q^2) yields as ratio of the axial and vector coupling constants gA/gV=1.22±0.05 (stat.)±0.10 (syst.)|g_{\rm A}/g_{\rm V}| = 1.22 \pm 0.05~({\rm stat.}) \pm 0.10~({\rm syst.}), which validates the sum rule to an accuracy of about 9\%.Comment: 19 pages, 8 figures and table

    Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data

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    Using a novel analysis technique, the gluon polarisation in the nucleon is re-evaluated using the longitudinal double-spin asymmetry measured in the cross section of semi-inclusive single-hadron muoproduction with photon virtuality Q2>1 (GeV/c)2Q^2>1~({\rm GeV}/c)^2. The data were obtained by the COMPASS experiment at CERN using a 160 GeV/cc polarised muon beam impinging on a polarised 6^6LiD target. By analysing the full range in hadron transverse momentum pTp_{\rm T}, the different pTp_{\rm T}-dependences of the underlying processes are separated using a neural-network approach. In the absence of pQCD calculations at next-to-leading order in the selected kinematic domain, the gluon polarisation Δg/g\Delta g/g is evaluated at leading order in pQCD at a hard scale of μ2=Q2=3(GeV/c)2\mu^2= \langle Q^2 \rangle = 3 ({\rm GeV}/c)^2. It is determined in three intervals of the nucleon momentum fraction carried by gluons, xgx_{\rm g}, covering the range 0.04 ⁣< ⁣xg ⁣< ⁣0.280.04 \!<\! x_{ \rm g}\! <\! 0.28~ and does not exhibit a significant dependence on xgx_{\rm g}. The average over the three intervals, Δg/g=0.113±0.038(stat.)±0.036(syst.)\langle \Delta g/g \rangle = 0.113 \pm 0.038_{\rm (stat.)}\pm 0.036_{\rm (syst.)} at xg0.10\langle x_{\rm g} \rangle \approx 0.10, suggests that the gluon polarisation is positive in the measured xgx_{\rm g} range.Comment: 14 pages, 6 figure

    Multiplicities of charged pions and unidentified charged hadrons from deep-inelastic scattering of muons off an isoscalar target

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    Multiplicities of charged pions and unidentified hadrons produced in deep-inelastic scattering were measured in bins of the Bjorken scaling variable xx, the relative virtual-photon energy yy and the relative hadron energy zz. Data were obtained by the COMPASS Collaboration using a 160 GeV muon beam and an isoscalar target (6^6LiD). They cover the kinematic domain in the photon virtuality Q2Q^2 > 1(GeV/c)2)^2, 0.004<x<0.40.004 < x < 0.4, 0.2<z<0.850.2 < z < 0.85 and 0.1<y<0.70.1 < y < 0.7. In addition, a leading-order pQCD analysis was performed using the pion multiplicity results to extract quark fragmentation functions

    Transverse-momentum-dependent Multiplicities of Charged Hadrons in Muon-Deuteron Deep Inelastic Scattering

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    A semi-inclusive measurement of charged hadron multiplicities in deep inelastic muon scattering off an isoscalar target was performed using data collected by the COMPASS Collaboration at CERN. The following kinematic domain is covered by the data: photon virtuality Q2>1Q^{2}>1 (GeV/cc)2^2, invariant mass of the hadronic system W>5W > 5 GeV/c2c^2, Bjorken scaling variable in the range 0.003<x<0.40.003 < x < 0.4, fraction of the virtual photon energy carried by the hadron in the range 0.2<z<0.80.2 < z < 0.8, square of the hadron transverse momentum with respect to the virtual photon direction in the range 0.02 (GeV/c)2<PhT2<3c)^2 < P_{\rm{hT}}^{2} < 3 (GeV/cc)2^2. The multiplicities are presented as a function of PhT2P_{\rm{hT}}^{2} in three-dimensional bins of xx, Q2Q^2, zz and compared to previous semi-inclusive measurements. We explore the small-PhT2P_{\rm{hT}}^{2} region, i.e. PhT2<1P_{\rm{hT}}^{2} < 1 (GeV/cc)2^2, where hadron transverse momenta are expected to arise from non-perturbative effects, and also the domain of larger PhT2P_{\rm{hT}}^{2}, where contributions from higher-order perturbative QCD are expected to dominate. The multiplicities are fitted using a single-exponential function at small PhT2P_{\rm{hT}}^{2} to study the dependence of the average transverse momentum PhT2\langle P_{\rm{hT}}^{2}\rangle on xx, Q2Q^2 and zz. The power-law behaviour of the multiplicities at large PhT2P_{\rm{hT}}^{2} is investigated using various functional forms. The fits describe the data reasonably well over the full measured range.Comment: 28 pages, 20 figure
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