Статьи

В работе рассматривается предобусловливатель блочного неполного обратного треугольного разложения первого порядка “по значению” BIIC-IC1 для решения систем линейных алгебраических уравнений с симметричной положительно определенной матрицей. Рассматривается способ применения MPI+OpenMP технологии для построения и обращения предобусловливателя BIIC-IC1, при этом в предобусловливателе число блоков кратно числам используемых процессоров и используемых потоков. Предлагается способ применения MPI+OpenMP технологии для построения и обращения предобусловливателя BIIC-IC1, в котором для применения OpenMP технологии используется специальное упорядочение узлов сетки внутри подобластей, соответствующих расчетам на процессорах. Проводится сравнение времени решения задач методом сопряженных градиентов с предобусловливателем BIIC-IC1 с использованием MPI и гибридной MPI+OpenMP технологии на примере модельной задачи и ряда задач из коллекции разреженных матриц SuiteSparse.

The convection-diffusion equation with dominant convection is considered on a uniform grid of central difference scheme. The multigrid method is used for solving the strongly nonsymmetric systems of linear algebraic equations with positive definite coefficient matrices. Two-step skew-Hermitian iterative methods are utilized for the first time as a smoothing procedure. It is demonstrated that using the proper smoothers enables to improve the convergence of the multigrid method. The robustness of the smoothers with respect to variation of the Peclet number is shown by local Fourier analysis and numerical experiments.

Mitochondrial dysfunctions (an impaired energy metabolism in the mitochondria) are essential in a pathogenesis of many diseases. Aim. The analysis of various mitochondrial dysfunction (MD) type study, as well as evaluation of drugs with an antihypoxic effect in their treatment. Methods. Collection, systematization and analysis of experimental and clinical data of current scientific research about the problem. Results. The mitochondrial dysfunctions can be caused by
genetic disorders of the mitochondrial or nuclear genome (the primary MD or the mitochondrial diseases), as well as structural, functional and biochemical defects of mitochondria
caused by other diseases (the secondary MD). MD are characterized by impaired tissue respiration, ATP synthesis deficiency and decreased energy metabolism. The clinical
implications of MD are polysystemic and polymorphic. One of the biochemical sign of MD is the lactic acidosis. There are certain difficulties with the early diagnosis of primary MD.
It is suggested to use complete exome sequencing among patients with a clinical suspicion on mitochondrial disease. The energotropic pharmacotherapy including drugs with an antihypoxic
effect is used for MD treatment. It is more rational to use the drug combination that influences different stages of energy production. The combinations of L-carnitine, coenzyme Q10, cytochrome C and succinate-containing drugs are frequently used for MD. However, the usage of energotropic and antihypoxic drugs is not able to cure the patients and stop the progression of all disease displays. Conclusion. MD are a multidisciplinary problem, therefore, doctors of any speciality must be competent in the MD diagnosis and treatment. The use of energotropic agents in the MD treatment requires further research. Numerous issues remain open (daily drug
doses choice, treatment duration, rational combinations). The phenotype variability and the uniqueness of diagnosed cases, clinical and genetic differences between patient groups
with mitochondrial disease

Domestic revenue mobilisation has become a topical issue in developing countries, and their capacity to regulate multinational enterprises (MNE) transactions to minimise Base Erosion and Profit Shifting (BEPS) remains a formidable task. Faced with legislative deficiencies, implementation incapacities, and being at the nascent stages of adopting transfer pricing (TP) regulation, developing countries have remained at the mercy of MNEs’ BEPS practices. The complexity and intricacies of intragroup transactions have an impact on profit allocation, thus affecting the distribution of taxing rights across countries where these MNEs operate. This study explores the regulatory policies toward international transfer pricing in the context of developing
nations and the associated challenges. The paper proffers possible solutions to improve TP regulation and implementation. Specifically, the paper centres its attention on Zimbabwe, one of the developing nations that have implemented transfer pricing legislation in recent years. Mitigating the impact of BEPS through efforts, such as regulating and managing TP would avail potential substantial finance to shift developing countries from aid dependence to self-sustenance, yet these efforts face a lot of hurdles. Research that contributes to knowledge development in the area, evaluates the hurdles faced and contributes to policy and implementation improvements becomes vital. This study found that Zimbabwe is faced with challenges such as lack of legislative clarity, lack of comparability data, shortage of resources, lack of capacity and dysfunctional double taxation agreements in dealing with transfer pricing. The study recommends Zimbabwe should improve legislation, create TP databases, improve revenue authorities’ capacity, and increase stakeholder awareness of TP.

The article examines recent trends in tax level and structure changes within developed and developing economies in relation to economic growth. The study’s significance stems from increasing geo-economic turbulence and emerging risks in the global economy, necessitating fiscal regulation. The analysis spans the period from 2009, post the Great Recession, to the present day.

We tested the hypothesis that discernible patterns could be identified through statistical analysis regarding the relationship between tax indicators (level and structure) and economic growth indicators. However, no such clear patterns were found. In essence, it cannot be definitively concluded that reduced tax levels and/or increased indirect tax shares do explicitly foster national economic growth. Tax impact on economic growth varies significantly across developed and developing economies, presenting a complex and nuanced picture. The nature and strength of this influence are largely shaped by the specific circumstances of each location and period. In order to identify their unique impact, counterfactual analysis is required.

In the course of further research, it is important to consider, firstly, the increased fiscal activism of the post-pandemic period: in this case, the research outcomes may be different from those obtained for the period already examined. Secondly, considering the ongoing processes of geo-economic fragmentation, it is recommended to reexamine the influence of taxes on economic processes. This investigation should adhere to the evolving framework of new macro-regions worldwide, rather than the conventional dichotomy of developed and developing economies. Participants within these macro-regions, interconnected through supply and value chains, will
need to work together to align their tax rules and policies for mutual benefits.

The objective of this paper is to analyze the characteristics of models of a complex system of mankind. The opportunities for the actions of people and humanity are included in the model of the system. Social structures as well as the impact of humanity on the environment are excluded from the model. A small quantitative model of mankind’s system has been previously presented in my papers. The elements of small and big models are resources or resource groups. By resources, we mean tools, things, qualities, and methods that can be used to achieve human goals.
This article introduces a set of regional models in addition to small model of the humankind system.
It is shown that the proposed regional models are the models of complex systems. The characteristics of these models are considered.
This article has an interdisciplinary nature. It addresses the issues of complex systems and the history of mankind.