6 research outputs found
Equation-free multiscale computations in social networks: From agent-based modeling to coarse-grained stability and bifurcation analysis
No full text We focus on the "trijunction" between multiscale computations, bifurcation theory and social networks. In particular, we address how the Equation-Free approach, a recently developed computational framework, can be exploited to systematically extract coarse-grained, emergent dynamical information by bridging detailed, agent-based models of social interactions on networks, with macroscopic, systems-level, continuum numerical analysis tools. For our illustrations, we use a simple dynamic agent-based model describing the propagation of information between individuals interacting under mimesis in a social network with private and public information. We describe the rules governing the evolution of the agents' emotional state dynamics and discover, through simulation, multiple stable stationary states as a function of the network topology. Using the Equation-Free approach we track the dependence of these stationary solutions on network parameters and quantify their stability in the form of coarse-grained bifurcation diagrams. </jats:p
Wildland fire spread modelling using cellular automata: Evolution in large-scale spatially heterogeneous environments under fire suppression tactics
No full textWe show how microscopic modelling techniques such as Cellular Automata linked with detailed geographical information systems (GIS) and meteorological data can be used to efficiently predict the evolution of fire fronts on mountainous and heterogeneous wild forest landscapes. In particular, we present a lattice-based dynamic model that includes various factors, ranging from landscape and earth statistics, attributes of vegetation and wind field data to the humidity of the fuel and the spotting transfer mechanism. We also attempt to model specific fire suppression tactics based on air tanker attacks utilising technical specifications as well as operational capabilities of the aircrafts. We use the detailed model to approximate the dynamics of a large-scale fire that broke out in a region on the west flank of the Greek National Park of Parnitha Mountain in June of 2007. The comparison between the simulation and the actual results showed that the proposed model predicts the fire-spread characteristics in an adequate manner. Finally, we discuss how such a detailed model can be exploited in order to design and develop, in a systematic way, fire risk management policies.</jats:p
Reconstructive endovascular treatment of basilar artery fenestration aneurysms: A multi-centre experience and literature review
No full textBackground: Data on outcome after endovascular treatment of basilar artery fenestration aneurysms (BAFAs) is limited. This study presents our multi-centre experience of BAFAs treated by different reconstructive techniques including coils, stent-assisted coiling (SAC), flow diversion and intra-saccular flow disruption with the Woven Endobridge (WEB). Methods: Retrospective analysis of 38 BAFAs treated endovascularly between 2003 and 2020. The primary endpoint was complete aneurysm obliteration defined as Raymond–Roy occlusion classification (RROC) I on immediate and follow-up (FU) angiography. The secondary endpoints were procedure-related complications, rate of re-treatment, and clinical outcome. Results: Endovascular treatment was feasible in 36/38 aneurysms (95%). The most frequent strategy was coiling (21/36, 58%), followed by SAC (7/36, 19%), WEB embolization (6/36, 17%) and flow diversion (2/36, 6%). A successful aneurysm occlusion (defined as RROC 1 and 2) on the final angiogram was achieved in 30/36 (83%) aneurysms including all patients presenting with baseline subarachnoid haemorrhage and 25/36 (69%) were occluded completely. Complete occlusion (RROC 1) was more frequently achieved in ruptured BAFAs (15/25, 60% v. 2/11, 18%; p = 0.031). Procedure-related complications occurred in 3/36 (8%) aneurysms. Re-treatment was executed in 12/36 (33%) aneurysms. After a median angiography FU of 38 months, 30/31 (97%) BAFAs were occluded successfully and 25/31 (81%) showed complete occlusion. Conclusion: Reconstructive endovascular treatment of BAFAs is technically feasible with a good safety profile. Although in some cases re-treatment was necessary, a high rate of final aneurysm occlusion was achieved. © The Author(s) 2021
Practical Recommendations of Scientific Society for the Study of Human Microbiome and the Russian Gastroenterological Association on Use of Probiotics, Prebiotics, Synbiotics and Functional Foods in Treatment and Prevention of Gastroenterological Diseases in Children and Adults
No full textAim. The practical guidelines are intended for primary care physicians, general practitioners, paediatricians, gastroenterologists and general internists to advance the treatment and prevention of gastroenterological diseases in adults and children in therapies with probiotics, prebiotics, synbiotics and their enriched functional foods.Key points. Probiotics are live microorganisms that sustain health of the host when supplied in adequate amounts. Prebiotics include human-indigestible but accessible to gut microbiota substances expediting specific changes in the composition and/or activity of gastrointestinal microbiota that favour the host health. The mechanism of probiotic action comprises the quorum resistance maintenance, nutrient substrate metabolism and end metabolite recycling, macroorganism-sustaining substrate production, as well as the mediation of local and adaptive immune responses.The Russian Federation regulates market differently for biologically active food additives (BAFA), medicinal products (drugs) and functional food products (FFP). We overview the probiotic strains regulated in Russia as BAFAs, drugs and FFPs and provide recommendations on the use of these strains in treatment and prevention of gastroenterological diseases in children and adults.Conclusion. The clinical efficacy of probiotics, prebiotics, synbiotics and fortified functional foods depends on the prebiotic and strain properties and is verified in appropriate comparative clinical trials. Not all probiotics registered in Russia as BAFAs, drugs and FFPs have a strain identity, which provides no warranty of the clinical effect expected. The FFP legislation demands improved regulation mechanisms and control for therapeutic efficacy
Nutraceuticals and Pharmaceuticals
No full textAim. To provide a definition and classification of nutraceutical products and to show their significane in modern integrative medicine.Background. Nutraceuticals are foodstuffs and their components, which have a positive effect on human health, including preventive maintenance and treatment of diseases. Nutraceuticals include healthy and functional foods, as well as biologically active food additives (BAFA). Healthy foods are nutritional foodstuffs without any artificial modification. These include organic, whole, and natural foods. Alongside a high nutritional value, functional food products have a positive effect on the human body due to functional food ingredients. BAFAs are food additives that contains one or several food ingredients (vitamins, mineral substances, plant components, amino acids and others). Specialists express conflicting viewpoints concerning nutraceuticals. Some nutraceuticals, such as probiotics, have confirmed their effectiveness in clinical trials, while the beneficial properties of others require further elucidation.Conclusions. The application of nutraceuticals, as well as their combined use with pharmaceuticals, in accordance with recommendations by scientific professional associations formulated on the basis of valid research studies can lead to an improvement in the quality of the life and longevity of the population. This position forms a basis for the development of integrative medicine — a contemporary approach to the treatment of diseases
