Nonisospectral integrable nonlinear equations with external potentials and their GBDT solutions

Auxiliary systems for matrix nonisospectral equations, including coupled NLS with external potential and KdV with variable coefficients, were introduced. Explicit solutions of nonisospectral equations were constructed using the GBDT version of the B\"acklund-Darboux transformation

Maxwell-Bloch equation and Correlation function for penetrable Bose gas

We consider the quantum nonlinear Schr\"odinger equation in one space and one time dimension. We are interested in the non-free-fermionic case. We consider static temperature-dependent correlation functions. The determinant representation for correlation functions simplifies in the small mass limit of the Bose particle. In this limit we describe the correlation functions by the vacuum expectation value of a boson-valued solution for Maxwell-Bloch differential equation. We evaluate long-distance asymptotics of correlation functions in the small mass limit.Comment: LaTEX file, 20 pages, to appear J. Phys. A (1997

INVERSE SCATTERING TRANSFORM ANALYSIS OF STOKES-ANTI-STOKES STIMULATED RAMAN SCATTERING

Zakharov-Shabat--Ablowitz-Kaup-Newel-Segur representation for Stokes-anti-Stokes stimulated Raman scattering is proposed. Periodical waves, solitons and self-similarity solutions are derived. Transient and bright threshold solitons are discussed.Comment: 16 pages, LaTeX, no figure

Investigation of oxidation process of mechanically activated ultrafine iron powders

The oxidation of mechanically activated ultrafine iron powders was studied using X-ray powder diffraction and thermogravimetric analyzes. The powders with average particles size of 100 nm were made by the electric explosion of wire, and were subjected to mechanical activation in planetary ball mill for 15 and 40 minutes. It was shown that a certain amount of FeO phase is formed during mechanical activation of ultrafine iron powders. According to thermogravimetric analysis, the oxidation process of non-milled ultrafine iron powders is a complex process and occurs in three stages. The preliminary mechanical activation of powders considerably changes the nature of the iron powders oxidation, leads to increasing in the temperature of oxidation onset and shifts the reaction to higher temperatures. For the milled powders, the oxidation is more simple process and occurs in a single step

Explicit solutions of the four-wave mixing model

The dynamical degenerate four-wave mixing is studied analytically in detail. By removing the unessential freedom, we first characterize this system by a lower-dimensional closed subsystem of a deformed Maxwell-Bloch type, involving only three physical variables: the intensity pattern, the dynamical grating amplitude, the relative net gain. We then classify by the Painleve' test all the cases when singlevalued solutions may exist, according to the two essential parameters of the system: the real relaxation time tau, the complex response constant gamma. In addition to the stationary case, the only two integrable cases occur for a purely nonlocal response (Real(gamma)=0), these are the complex unpumped Maxwell-Bloch system and another one, which is explicitly integrated with elliptic functions. For a generic response (Re(gamma) not=0), we display strong similarities with the cubic complex Ginzburg-Landau equation.Comment: 16 pages, J Phys A Fast track communication, to appear 200

Medical therapy in the immediate and late postoperative periods after a partial transurethral resection of the prostate in the middle-aged men

In paper analysis of the results of alpha - blockers monotherapy application and combined therapy of alpha - blockers and muscarinic receptor antagonists in the immediate and late postoperative periods after partial transurethral resection of prostate, performed due to benign prostatic hyperplasia in the middle aged men (up to 55 y.o.) is presented. It’s revealed that in the middle aged patients who underwent partial TURP the short and long-term postoperative use of a combination of alpha - blockers and muscarinic receptor antagonists to relieve effects of dysuria and irritative symptoms and to preserve the copulative (ejaculatory) function is more preferable than monotherapy with alpha -1 - adrenergic blockers. No significant differences in the effectiveness of therapy with superselective (tamsulosin) and selective (doxazosin) alpha -1 - adrenergic blockers are observed, although special for each drug side — effects were detected. The combination technique of partial TURP for BPH and medical treatment held in the postoperative period preserves antegrade ejaculation in the majority (89,5%) of the middle aged patients, thus minimizing the influence on their quality life after surgery.В работе представлен анализ результатов применения монотерапии альфа - адреноблокаторами и комбинированной терапии альфа - адреноблокаторами и антагонистами мускариновых рецепторов у мужчин среднего возраста (до 55лет) в ближайшем и отдаленном послеоперационном периодах после парциальной трансуретральной резекции простаты, выполненной по поводу доброкачественной гиперплазии предстательной железы. В исследовании показано, что у пациентов среднего возраста, подвергшихся парциальной ТУР простаты, в ближайшем и отдаленном послеоперационном периодах применение комбинации альфа - адреноблокаторов и М - холинолитиков с целью купирования явлений дизурии и ирритативной симптоматики и сохранения копулятивной (зякуляторной) функции является более эффективным, чем монотерапия альфа -1 - адренблокаторами. Достоверных различий в эффективности терапии при использовании сверхселективных (тамсулозин) и селективных (доксазозин) альфа - 1 - адреноблокаторов не получено, хотя во время лечения были отмечены характерные для каждого препарата побочные явления. Сочетание методики парциальной ТУР простаты при ДГПЖ и проводимого в послеоперационном периоде медикаментозного лечения обеспечивает сохранение антеградной эякуляции у подавляющего большинства (89,5%) пациентов среднего возраста, что минимизирует снижение качества жизни данной категории больных после операции

Ways to increase adherence to antihypertensive therapy

With a high prevalence in the Russian population and insufficient effectiveness of treatment, hypertension remains a poorly controlled cardiovascular risk factor, including due to the low compliance of patients. Noncompliance is due to a large number of factors, some of which were studied in post-hoc analysis of the Russian observational STIL’ and TRICOLOR studies. It demonstrated that fixed-dose combinations of antihypertensive drugs can make a significant contribution to solving such a complex problem as low compliance

Existence and stability of hole solutions to complex Ginzburg-Landau equations

We consider the existence and stability of the hole, or dark soliton, solution to a Ginzburg-Landau perturbation of the defocusing nonlinear Schroedinger equation (NLS), and to the nearly real complex Ginzburg-Landau equation (CGL). By using dynamical systems techniques, it is shown that the dark soliton can persist as either a regular perturbation or a singular perturbation of that which exists for the NLS. When considering the stability of the soliton, a major difficulty which must be overcome is that eigenvalues may bifurcate out of the continuous spectrum, i.e., an edge bifurcation may occur. Since the continuous spectrum for the NLS covers the imaginary axis, and since for the CGL it touches the origin, such a bifurcation may lead to an unstable wave. An additional important consideration is that an edge bifurcation can happen even if there are no eigenvalues embedded in the continuous spectrum. Building on and refining ideas first presented in Kapitula and Sandstede (Physica D, 1998) and Kapitula (SIAM J. Math. Anal., 1999), we show that when the wave persists as a regular perturbation, at most three eigenvalues will bifurcate out of the continuous spectrum. Furthermore, we precisely track these bifurcating eigenvalues, and thus are able to give conditions for which the perturbed wave will be stable. For the NLS the results are an improvement and refinement of previous work, while the results for the CGL are new. The techniques presented are very general and are therefore applicable to a much larger class of problems than those considered here.Comment: 41 pages, 4 figures, submitte