Approximation of complex, multiparameter, essentially nonlinear, dynamic relationships based on genetic algorithms

The work is focused on usage of genetic algorithms to get more precise approximation of complex and essentially nonlinear dynamic relationships. The algorithms precision was measured based on the model of stock market index prediction

Modified hybrid genetic algorithm of discreet optimization problems

The goal objective is to improve the efficiency of solving discrete optimization problems. The proposed method refers to the “fast” methods and was named the “Local genetic method”. The peculiarity of this method is that the chromosomes do not encode the whole solution, but only a small part of the plan. Therefore, the method allows us introducing unary and binary operations that take into account the specific nature of the problem. The important feature of the method is the non-deterministic nature of the computation, which is due to the internal parallelism of computations and is expressed in the asynchronous action of various local strategies. In terms of speed, the proposed method in a number of experiments outperformed the traditional algorithm by more than 10 times and always found the best solution. The nature of the approximation to the optimum for these algorithms remained unchanged when solving any test cases

The review (typology) of small and medium-sized business in Russia and abroad

The article examines the problem of classification of small and medium-sized business in Russia, which is relevant due to the increase in state support for them, in order to increase the targeting of the support provided. The article also discusses the development of small and medium-sized business in Russia since the end of the previous century, its gradually changing legislative regulation and comparison of criteria for classification of small and medium-sized business in Russia and foreign countries. In addition, the question is raised about small and medium-sized business falling out of the official classification, while, by their nature of activity, do not cease to be such and possible causes of this phenomenon. In order to resolve controversial issues of classification, some assumptions and possible ways to solve are put forward in the article on the basis of the conducted research that can eliminate gaps in legislation. Within the framework of writing this article, such scientific research methods were used as analysis and generalization of domestic and foreign anti-crisis measures

Understanding the structure and reactivity of NiCu nanoparticles: An atomistic model

The structure of bimetallic NiCu nanoparticles (NP) is investigated as a function of their composition and size by means of Lattice MonteCarlo (LMC) and molecular dynamics (MD) simulations. According to our results, copper segregation takes place at any composition of the particles. We found that this feature is not size-dependent. In contrast, nickel segregation depends on the NP size. When the size increases, Ni atoms tend to remain in the vicinity of the surface and deeper. For smaller NPs, Ni atoms are located at the surface as well. Our results also showed that most of the metal atoms segregated at the surface area were found to decorate edges and/or form islands. Our findings agree qualitatively with the experimental data found in the literature. In addition, we comment on the reactivity of these nanoparticles.Fil: Quaino, Paola Monica. Universidad Nacional del Litoral. Instituto de Química Aplicada del Litoral. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Química Aplicada del Litoral.; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Electroquímica Aplicada e Ingeniería Electroquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Belletti, Gustavo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional del Litoral. Instituto de Química Aplicada del Litoral. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Química Aplicada del Litoral.; Argentina. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Programa de Electroquímica Aplicada e Ingeniería Electroquímica; ArgentinaFil: Shermukhamedov, S. A.. Kazan National Research Technological University; RusiaFil: Glukhov, D. V.. Kazan National Research Technological University; RusiaFil: Santos, Elizabeth del Carmen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Física Enrique Gaviola. Universidad Nacional de Córdoba. Instituto de Física Enrique Gaviola; Argentina. Institute of Theoretical Chemistry; Alemania. Universitat Ulm; AlemaniaFil: Schmickler, Wolfgang. Universitat Ulm; Alemania. Institute of Theoretical Chemistry; AlemaniaFil: Nazmutdinov, Renat. Kazan National Research Technological University; Rusi

Изолированная резекция вены в хирургическом лечении протоковой карциномы поджелудочной железы как фактор резектабельности

Background. Pancreatic ductal carcinoma (PDC) with involvement of the superior mesenteric vein (SMV) or/ and portal vein (PV) remains a discussible subject. We have evaluated vein invasion as a criterion of borderline resectability and long-term outcome. Material and methods. In our center, 68 patients underwent either 65 standard pancreatoduodenal resections or 3 pancreatoduodenectomies for PDC. Resection of SMV/PV was performed in 18 cases (26.5 %). Three patients received neoadjuvant chemotherapy (NACT), and adjuvant chemotherapy (ACT) was assigned to 37 patients (54.4 %). Results. Morbidity (42.0 vs 50.0 %, р=0.590) and mortality rates (4.0 vs 16.7 %, р=0.111) had no significant differences in groups of standard and angioplasty operations respectively. ACT was completed in 10 (16.7 %) patients only. There was true vein invasion in 12 of 18 patients with vein resection. рN+ (р=0.012) and angioplasty by itself (р<0.001) were found out as independent predictors of overall survival (OS). the median OS was 9.4 mo in patients with vein resection. in the group of standard operations, the median OS was 26.9 mo (р<0.001). The median OS in patients with vein resection and complete chemotherapy was 17.7 mo in contrast to 8.9 mo in those who did not receive chemotherapy (р=0.439). Conclusions. PDR with vein resection and incomplete chemotherapy cannot be regarded as a reasonable procedure. PDR with vein resection may be appropriate after efficient NACT.Лечение протоковой карциномы поджелудочной железы (ПКПЖ) с вовлечением верхней брыжеечной и/или воротной вены остается предметом дискуссий. Мы оценили венозную инвазию как критерий пограничной резектабельности и отдаленного прогноза заболевания. Материал и методы. В нашем центре 68 пациентов оперированы в объеме стандартной панкреатодуоденальной резекции (n=65) или панкреатодуоденэктомии (n=3) по поводу ПКПЖ. В 18 (26,5 %) наблюдениях выполнена резекция верхней брыжеечной и/или воротной вены. Неоадъювантную химиотерапию (НАХТ) получили 3 пациента, адъювантная химиотерапия (АХТ) начата у 37 (54,4 %) пациентов. Результаты. Частота послеоперационных осложнений в группе стандартных операций и ангиопластических операций (42,0 против 50,0 %, р=0,590), частота летальных исходов (4 против 16,7 %, р=0,111) значимо не отличались. АХТ закончена полностью у 10 (16,7 %) пациентов. Истинная инвазия опухоли отмечена у 12 из 18 пациентов с резекцией вены. Независимыми предикторами общей выживаемости (ОВ) были рN+ (р=0,012) и наличие ангиопластики (р=0,000). У пациентов с резекцией вены медиана ОВ составила 9,4 мес. В группе стандартных ПДР медиана ОВ была 26,9 мес (р=0,000). У пациентов с резекцией вены медиана ОВ при законченной химиотерапии составила 17,7 мес, без химиотерапии – 8,9 мес (р=0,439). Заключение. ПДР с резекцией вены и отсутствием или незавершенной химиотерапией может рассматриваться как неоправданная операция. Данную операцию целесообразно выполнять после эффективной НАХТ

Treatment of patients with anterior urethral strictures: the role of perineal urethrostomy

The article reviews the 2000-2020 literature on the use of perineal urethrostomy in the treatment of patients with anterior urethral strictures. Historical issues of the development of urethrostomy techniques are considered. The algorithms to choose the method of treatment of urethral strictures in favor of perineal urethrostomy are highlighted, according to the guidelines of the world's professional urological associations. The performance indicators of perineal urethrostomy were studied considering the age characteristics of the patients, the etiological genesis of the strictures, their length and location, as well as depending on the surgical technique and the follow-up period. Considerable attention is paid to studies devoted to the analysis of the functional results of urethrostomy, as well as the quality of life of patients associated with urination and sexual activity. Data are presented on the incidence of early and late surgical complications, including urethrostomy stenosis, as one of the most common. An analysis of studies evaluating factors that negatively affect the outcome of surgery was carried out. The main reasons for the growing demand for the technique in surgery for complex anterior urethral strictures and the importance of the technique among other treatment methods are discussed

РЕЗЕКЦИЯ АРТЕРИЙ В ХИРУРГИИ РАКА ПОДЖЕЛУДОЧНОЙ ЖЕЛЕЗЫ: ОПЫТ ОДНОГО УЧРЕЖДЕНИЯ

Pancreaticoduodenal resection (PDR) with vascular reconstruction is performed in approximately 20 % of pancreatic cancer patients. The superior mesenteric vein resection and reconstruction has become a standard routine surgery, whereas arterial resection during pancreatic surgery is still an issue of controversial debate.The purpose of the study was to evaluate short-and long-term outcomes of PDR with reconstruction of various arteries.Material and Methods. Outcomes of 89 PDRs and pancreaticoduodenectomies performed in patients with stage II–IV periampullary carcinoma were assessed. The average age of the patients was 63.1 ± 8.2. There were 18 (20.2 %) PDRs with vascular reconstruction, of them 7 (7.8 %) were arterial resections.Results. In patients who underwent artery resection (n=7), complications were observed in 5 (71.4 %) cases. Out of 71 patients who underwent PDR without arterial and/or venous resection, 29 (40.8 %) had complications (p=0.229). The postoperative mortality rates were 1 (14.3 %) and 3 (4.2 %), respectively (p=0.319). The median disease-free survival was 5.0 months (95 % CI 2.4–7.6 months) in the arterial resection group and 12.3 months (95 % CI 9.2–15.4 months) in the standard surgery group (log-rank test, p=0,011). The median overall survival was 8.0 months (95 % CI 3.7–12.3 months) in the in the arterial resection group and 21.8 months (95 % CI 15.9–27.7 months) in the standard surgery group (log-rank test, p=0.011).Conclusion. The disease-free and overall survival rates were significantly worse in the arterial resection group than in the standard surgery group. This is most likely due to a small sample of patients. Further studies are needed to analyze the immediate and long-term treatment outcomes of PDR with arterial resection for pancreatic cancer. Панкреатодуоденальная резекция (ПДР) с пластикой сосудов по поводу рака поджелудочной железы выполняется примерно в 20 % случаев. В то время как резекция и пластика верхней брыжеечной вены является рутинно выполняемой операцией, целесообразность резекции артерий при ПДР остается предметом дискуссии.Цель исследования – оценить непосредственные и отдаленные результаты выполнения панкреатодуоденальных резекций с пластикой различных артерий.Материал и методы. Проанализированы результаты 89 панкреатодуоденальных резекций и панкреатодуоденэктомий, выполненных по поводу злокачественных опухолей периампулярной локализации II–IV стадий. Средний возраст пациентов составил 63,1 ± 8,2 года. Ангиопластических операций было 18 (20,2 %), из них 7 артериопластик.Результаты и обсуждение. В группе пациентов (n=7), перенесших резекцию артерии, послеоперационные осложнения развились в 5 (71,4 %) случаях, у 71 больного, которым выполнялись ПДР без пластики артерии и/или вены, осложнения возникли в 29 (40,8 %) наблюдениях (р=0,229). Послеоперационная летальность составила 1 (14,3 %) и 3 (4,2 %) случая соответственно (р=0,319). Медиана безрецидивной выживаемости при артериопластических операциях составила 5,0 мес (95 % ДИ 2,4–7,6 мес), при стандартных вмешательствах – 12,3 мес (95 % ДИ 9,2–15,4 мес) (log-rank test, p=0,011); медиана общей выживаемости – 8,0 мес (95 % ДИ 3,7–12,3 мес) и 21,8 мес (95 % ДИ 15,9–27,7 мес) (log-rank test, p=0,011).Выводы. Показатели безрецидивной и общей выживаемости значимо хуже при панкреатодуоденальных резекциях с артериопластикой, что, возможно, связано с малой выборкой пациентов. Необходимо проведение масштабных исследований с целью изучения непосредственной и отдаленной эффективности ПДР с ангиопластическим компонентом, выполненных по поводу злокачественных новообразований поджелудочной железы.

Multi-stage urethroplasy for anterior urethral strictures: objective parameters of long-term efficacy and patient-reported outcomes

Introduction. Multi-stage urethral surgery is used in cases of the most complex urethral strictures. The evaluation of surgical treatment results given by patients is a significant criterion for the efficacy of urethroplasty along with the assessment of urethral patency through instrumental examinations.Objective. To evaluate the long-term efficacy of multistage urethroplasty for complex anterior urethral strictures considering the patients' quality of life and satisfaction with the surgical outcomes.Materials and methods. The study included 73 patients aged 18 – 84 years with anterior urethral strictures who underwent multi-stage urethroplasty in 2010 – 2019. Surgical and functional outcomes of urethroplasty were assessed through general blood and urine tests, physical examination, uroflowmetry, and retrograde urethrography and urethroscopy in case of urinary disorders.  Subjective parameters of treatment efficacy were studied using questionnaires: International Prostate Symptom Score (IPSS); Quality of life (QoL); Patient-reported Outcome Measure for Urethral Stricture Surgery (USS-PROM); Patient Global Impression of Improvement (PGI-I).Results. Recurrent urethral stricture was detected in 19 (26,0%) patients with the average follow-up period being 65 months. Independent urination was restored in 71 (97.3%) cases, including repeated interventions. After surgery, there was a significant increase in urinary flow rate parameters (Q max: 8.1 vs 19.1 ml/s, p < 0.0001; Q ave: 5.5 vs 10.7 ml/s; p = 0.0004), decrease in residual urine volume (62.4 vs 18.6 ml, p < 0.0001), decrease in total IPSS score (18.7 vs 5.7 points; p < 0.0001) and QoL index (4.3 vs 1 .8 points, p < 0.0001). A comparative analysis of preoperative and postoperative USS-PROM questionnaire results demonstrated an improvement in indicators assessing LUTS (12.9 vs 3.4 points; p < 0.0001; 3.6 vs 1.7 points; p < 0.0001), and urination-associated quality of life (2.6 vs 0.6 points; p < 0.0001) and overall health (EQ-5D index: 0.73 vs 0.91 points; p = 0.025; EQ-VAS: 68.0 vs 88.1 points, p = 0.004). Fifty-seven (81.4%) men were “very satisfied” or “satisfied” with the treatment outcomes, while nine (12.9%) respondents noted a moderate effect of residual urinary disorders on the quality of life. Significantly higher satisfaction was observed among cystostomy patients and in cases where repeated interventions were unnecessary.Conclusion. Multi-stage urethroplasty for complex anterior urethral strictures achieves efficacy in 97.3% of cases and is accompanied by high levels of quality of life and patient’s satisfaction during long-term follow-up

Непосредственные и отдаленные результаты резекций печени: опыт одного учреждения

The purpose of the study was to evaluate the outcomes of a series of liver resections performed in a single regional specialized cancer center. Material and Methods. Eighty-nine patients underwent liver and/ or extrahepatic bile duct resections in the Penza Regional Oncology Hospital over the 8-year study period. Malignancies were observed in 81 patients. Extended liver resections (4 segments or more) were performed in 58 (65.2 %) cases. Results. Postsurgical morbidity and mortality rates were 31.5 % (28 of 89) and 6.7 % (6 of 89), respectively. Six of 10 patients with primary liver carcinomas were alive without evidence of disease progression at a follow-up time ranged from 1.0 to 76.7 months. Adjuvant chemotherapy (ACT) was the only predictor (HR=0.40; 95 % CI 0.16-0.98) of overall survival in patients with metastatic colorectal cancer (mCRC). The median survival time after liver resections for mCRC with or without ACT was 54.5 (95 % CI: 14.5-94.5) vs 21.8 months (95 % CI: 14.2-29.4), respectively. In mCRC patients with ACT, the 5-year overall survival rate was 44.8 ± 12.9 %. Conclusion. Primary hepatobiliary carcinomas and colorectal cancer liver metastases are the most common reasons for liver resections. A series of liver resections in a low-volume hospital is feasible with the achievement of good outcomes.Цель исследования - оценка результатов серийного выполнения резекций печени в условиях регионального специализированного онкологического учреждения. Материал и методы. В Пензенском областном онкологическом диспансере за 8 лет резекции печени и/или внепеченочных желчных протоков выполнены 89 пациентам. Злокачественные опухоли были у 81 пациента. Обширные резекции (4 и более сегментов) проведены в 58 (65,2 %) наблюдениях. Результаты. Послеоперационные осложнения зарегистрированы у 28 (31,5 %) пациентов. Летальный исход наступил у 6 (6,7 %) из 89 человек. В группе первичных карцином печени из 10 пациентов шестеро живы в сроки от 1 до 76,7 мес. Адъювантная химиотерапия (АХТ) была единственным предиктором (HR=0,4; 95 % ДИ 0,16-0,98) общей выживаемости в группе больных с метастазами колоректального рака (мКРР). Медианы выживаемости с/без АХТ после резекции печени по поводу мКРР составили 54,5 (95 % ДИ 14,5-94,5) vs 21,8 мес (95 % ДИ 14,2-29,4) соответственно. 5-летняя выживаемость у больных с АХТ - 44,8 ± 12,9 %. Выводы. В структуре резекций печени превалируют операции по поводу первичных гепато-билиарных опухолей и метастазов колоректального рака. Серийное выполнение резекций печени в условиях медицинской организации 3-го уровня возможно с достижением устойчивого удовлетворительного результата

Precise measurement of RudsR_{\text{uds}} and RR between 1.84 and 3.72 GeV at the KEDR detector

The present work continues a series of the KEDR measurements of the $R$ value that started in 2010 at the VEPP-4M $e^+e^-$ collider. By combining new data with our previous results in this energy range we measured the values of $R_{\text{uds}}$ and $R$ at nine center-of-mass energies between 3.08 and 3.72 GeV. The total accuracy is about or better than $2.6\%$ at most of energy points with a systematic uncertainty of about $1.9\%$. Together with the previous precise $R$ measurement at KEDR in the energy range 1.84-3.05 GeV, it constitutes the most detailed high-precision $R$ measurement near the charmonium production threshold.Comment: arXiv admin note: text overlap with arXiv:1610.02827 and substantial text overlap with arXiv:1510.0266