Momentum Space Integral Equations for Three Charged Particles: Diagonal Kernels

It has been a long-standing question whether momentum space integral equations of the Faddeev type are applicable to reactions of three charged particles, in particular above the three-body threshold. For, the presence of long-range Coulomb forces has been thought to give rise to such severe singularities in their kernels that the latter may lack the compactness property known to exist in the case of purely short-range interactions. Employing the rigorously equivalent formulation in terms of an effective-two-body theory we have proved in a preceding paper [Phys. Rev. C {\bf 61}, 064006 (2000)] that, for all energies, the nondiagonal kernels occurring in the integral equations which determine the transition amplitudes for all binary collision processes, possess on and off the energy shell only integrable singularities, provided all three particles have charges of the same sign, i.e., all Coulomb interactions are repulsive. In the present paper we prove that, for particles with charges of equal sign, the diagonal kernels, in contrast, possess one, but only one, nonintegrable singularity. The latter can, however, be isolated explicitly and dealt with in a well-defined manner. Taken together these results imply that modified integral equations can be formulated, with kernels that become compact after a few iterations. This concludes the proof that standard solution methods can be used for the calculation of all binary (i.e., (in-)elastic and rearrangement) amplitudes by means of momentum space integral equations of the effective-two-body type.Comment: 36 pages, 2 figures, accepted for publication in Phys. Rev.

Proton-Deuteron Elastic Scattering from 2.5 to 22.5 MeV

We present the results of a calculation of differential cross sections and polarization observables for proton-deuteron elastic scattering, for proton laboratory energies from 2.5 to 22.5 MeV. The Paris potential parametrisation of the nuclear force is used. As solution method for the charged-composite particle equations the 'screening and renormalisation approach' is adopted which allows to correctly take into account the Coulomb repulsion between the two protons. Comparison is made with the precise experimental data of Sagara et al. [Phys. Rev. C 50, 576 (1994)] and of Sperison et al. [Nucl. Phys. A422, 81 (1984)].Comment: 24 pages, 8 eps figures, uses REVTe

Long-range behavior of the optical potential for the elastic scattering of charged composite particles

The asymptotic behavior of the optical potential, describing elastic scattering of a charged particle $\alpha$ off a bound state of two charged, or one charged and one neutral, particles at small momentum transfer $\Delta_{\alpha}$ or equivalently at large intercluster distance $\rho_{\alpha}$, is investigated within the framework of the exact three-body theory. For the three-charged-particle Green function that occurs in the exact expression for the optical potential, a recently derived expression, which is appropriate for the asymptotic region under consideration, is used. We find that for arbitrary values of the energy parameter the non-static part of the optical potential behaves for $\Delta_{\alpha} \rightarrow 0$ as $C_{1}\Delta_{\alpha} + o\,(\Delta_{\alpha})$. From this we derive for the Fourier transform of its on-shell restriction for $\rho_{\alpha} \rightarrow \infty$ the behavior $-a/2\rho_{\alpha}^4 + o\,(1/\rho_{\alpha}^4)$, i.e., dipole or quadrupole terms do not occur in the coordinate-space asymptotics. This result corroborates the standard one, which is obtained by perturbative methods. The general, energy-dependent expression for the dynamic polarisability $C_{1}$ is derived; on the energy shell it reduces to the conventional polarisability $a$ which is independent of the energy. We emphasize that the present derivation is {\em non-perturbative}, i.e., it does not make use of adiabatic or similar approximations, and is valid for energies {\em below as well as above the three-body dissociation threshold}.Comment: 35 pages, no figures, revte

Methodology of comprehensive assessment of the athlete's adaptive potential to the load

The review summarizes the current data on the methods of assessment of adaptation and disadaptation (fatigue, overreaching, overtraining, OT) of athlete during training; special attention is paid to the diagnostic value of biochemical and immunological markers of adaptation potential (AP). Their diagnostic significance was analyzed. Hypotheses and possible mechanisms of OT development were considered. Based on the results of recent studies published by domestic and foreign authors, both the diversity and the number of proposed adaptation markers have been established, and a lack of unity of approaches in the assessment of AP and OT has been revealed. Large amount of biochemical, immunological and other tests proposed for the evaluation of AP was summed up. The most significant AP and OT markers are protein metabolism factors, enzymes, lactate, urea. The role of immune factors, besides leukocytes and lymphocytes, is intensively studied: these are leukocyte toxicity index, level of neutrophils, cytokines, natural antibodies to AP bioregulators. The prospects of using an integrated test system for determining the e-At panel to AP bioregulators is shown for monitoring the athlete's condition, and especially for early diagnosis of OT

КЛИНИЧЕСКИЙ СЛУЧАЙ ГРАНУЛОЦИТАРНОГО АНАПЛАЗМОЗА ЧЕЛОВЕКА НА ТЕРРИТОРИИ АРХАНГЕЛЬСКОЙ ОБЛАСТИ

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КЛИНИЧЕСКИЙ СЛУЧАЙ СИНДРОМА МИЛЛЕРА - ФИШЕРА В ПРАКТИКЕ ДЕТСКИХ ИНФЕКЦИОННЫХ БОЛЕЗНЕЙ

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New approach to phase and modulation resolved spectra

Time domain fluorescence spectrometry offers a versatile and powerful approach to the analysis of heterogeneous emitting systems. In this paper we describe a new approach, based on software, to the acquisition of phase and modulation resolved spectra. Mixtures of fluorophores with different lifetimes can be analyzed in real time to give the individual excitation or emission spectra. Examples of two- and three-component mixtures are given and comparisons are made with the commercially available hardware approach. © 1985, American Chemical Society. All rights reserved

Диагностическая эффективность перфузионной компьютерной томографии миокарда с чреспищеводной электрокардиостимуляцией у больных с исходным диагнозом «острый коронарный синдром»

Introduction. Computed tomography angiography (CTA) is widely used to detect atherosclerotic changes in coronary arteries (CA). However, the method is limited by the impossibility to perform functional assessment of detected stenoses. Perfusion computed tomography of the myocardium (PCT) can be used for this purpose.Aim of the study. To assess diagnostic accuracy of PCT of the myocardium with transesophageal electrocardiostimulation (TEES) and stress-echocardiography (stress-echoCG) with veloergometry (VEM) in detection of transient ischemia in patients with initial diagnosis of “acute coronary syndrome” (ACS) with borderline stenoses (50–75%) in CA in relation to measurements of fractional flow reserve (FFR).Materials and Methods. The study included 30 patients with the initial diagnosis of ACS with borderline (50–75%) stenoses in CA according to CTA or coronary angiography (CAG). Subsequently, they underwent myocardial PCT with 320-row detector with TEES, as well as stress-echoCG with VEM. Invasive FFR measurement was used as a reference method. FFR value < 0.8 indicated hemodynamic significance of stenosis. Myocardial perfusion was assessed visually. Regional myocardial contractility of the left ventricle was assessed by stress-echoCG.Results. All patients were examined according to the stated protocol. PCT with TEES revealed FFR-significant stenoses with sensitivity, specificity, prognostic value of positive result and prognostic value of negative result 56, 93, 90, 65% respectively, stress-echoCG with VEM 62, 93, 91, 68% respectively.Conclusion. Myocardial PCT with TEES enables to detect perfusion defects associated with transient ischemia, and the diagnostic accuracy of the method in comparison with FFR is comparable with the already well-proven stress-echoCG. The use of PCT with TEES in combination with CTA can be considered as a promising diagnostic tool in patients without known coronary anatomy and with suspected ACS.Введение. Компьютерная томографическая ангиография (КТА) широко используется для выявления атеросклеротических изменений в коронарных артериях (КА). Однако метод ограничен невозможностью проведения функциональной оценки выявленных стенозов. С этой целью может использоваться перфузионная компьютерная томография миокарда (ПКТ).Цель исследования. Оценить диагностическую точность методов ПКТ миокарда с чреспищеводной электрокардиостимуляцией (ЧПЭС) и стресс-эхокардиографии (стресс-ЭхоКГ) с велоэргометрией (ВЭМ) в выявлении преходящей ишемии у больных с исходным диагнозом «острый коронарный синдром» (ОКС) с пограничными стенозами (50–75%) в КА по отношению к измерениям фракционного резерва кровотока (ФРК).Материалы и методы. В исследование были включены 30 больных с исходным диагнозом ОКС с пограничными (50–75%) стенозами в КА по данным КТА или коронарной ангиографии (КАГ). Впоследствии им были выполнены ПКТ миокарда на томографе с 320-рядным детектором с ЧПЭС, а также стресс-ЭхоКГ с ВЭМ. В качестве референтного метода использовалось инвазивное измерение ФРК. Значение показателя ФРК < 0,8 указывало на гемодинамическую значимость стеноза. Перфузия миокарда оценивалась визуально. При проведении стресс-ЭхоКГ оценивалась региональная сократимость миокарда левого желудочка.Результаты. Все больные обследованы согласно заявленному протоколу. ПКТ с ЧПЭС выявила ФРК-значимые стенозы с чувствительностью, специфичностью, прогностической ценностью положительного результата и прогностической ценностью отрицательного результата 56, 93, 90, 65% соответственно, стресс-ЭхоКГ с ВЭМ 62, 93, 91, 68% соответственно.Выводы. ПКТ миокарда с ЧПЭС позволяет выявить дефекты перфузии, ассоциированные с преходящей ишемией, а диагностическая точность метода при сравнении с ФРК сопоставима с уже хорошо зарекомендовавшей себя стресс-ЭхоКГ. Использование ПКТ с ЧПЭС в комбинации с КТА можно рассматривать как перспективный диагностический инструмент у больных без известной коронарной анатомии и с подозрением на ОКС