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1795. Assessment of local radial basis function collocation method for diffusion problems structured with multiquadrics and polyharmonic splinesIzaz Ali, Umut Hanoglu, Robert Vertnik, Božidar Šarler, 2024, original scientific article Abstract: This paper aims to systematically assess the local radial basis function collocation method, structured with multiquadrics (MQs) and polyharmonic splines (PHSs), for solving steady and transient diffusion problems. The boundary value test involves a rectangle with Dirichlet, Neuman, and Robin boundary conditions, and the initial value test is associated with the Dirichlet jump problem on a square. The spectra of the free parameters of the method, i.e., node density, timestep, shape parameter, etc., are analyzed in terms of the average error. It is found that the use of MQs is less stable compared to PHSs for irregular node arrangements. For MQs, the most suitable shape parameter is determined for multiple cases. The relationship of the shape parameter with the total number of nodes, average error, node scattering factor, and the number of nodes in the local subdomain is also provided. For regular node arrangements, MQs produce slightly more accurate results, while for irregular node arrangements, PHSs provide higher accuracy than MQs. PHSs are recommended for use in diffusion problems that require irregular node spacing. Keywords: meshless method, polyharmonic splines, multiquadrics, augmentation, heat diffusion equation Published in DiRROS: 04.04.2024; Views: 505; Downloads: 198 Full text (2,79 MB) This document has many files! More... |
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1797. Efects of chronic physical exercise on executive functions and episodic memory in clinical and healthy older adult populations : a systematic review and meta-analysis protocolSoledad Ballesteros, Andreea Badache, Vera Belkin, Christoforos D. Giannaki, Antonia Kaltsatou, Uroš Marušič, Mohammad Mosaferi Ziaaldini, Manca Peskar, José M. Reales, Jennifer A. Rieker, 2024, review article Abstract: Background Executive functions (EFs) and episodic memory are fundamental components of cognition that deteriorate with age and are crucial for independent living. While numerous reviews have explored the effect of exercise on these components in old age, these reviews screened and analyzed selected older adult populations, or specific exercise modes, thus providing only limited answers to the fundamental question on the effect of exercise on cognition in old age. This article describes the protocol for a systematic review and multilevel meta-analytic study aiming at evaluating the effectiveness of different types of chronic exercise in improving and/or maintaining EFs and long-term episodic memory in older adults. Methods and analysis The study protocol was written in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Several databases will be searched. Randomized controlled trials (RCTs) conducted in older adults aged ≥ 60 years providing any kind of planned, structured, and repetitive exercise interventions, and EFs and/or episodic memory measures as outcomes, published in English in peer-reviewed journals and doctoral dissertations will be included. Two independent reviewers will screen the selected articles, while a third reviewer will resolve possible conflicts. The Cochrane risk-of-bias tool will be used to assess the quality of the studies. Finally, data will be extracted from the selected articles, and the formal method of combining individual data from the selected studies will be applied using a random effect multilevel meta-analysis. The data analysis will be conducted with the metafor package in R. Discussion and conclusion This review will synthesize the existing evidence and pinpoint gaps existing in the literature on the effects of exercise on EFs and episodic memory in healthy and unhealthy older adults. Findings from this meta-analysis will help to design effective exercise interventions for older adults to improve and/or maintain EFs and episodic memory. Its results will be useful for many researchers and professionals working with older adults and their families. Keywords: diseased older adults, healthy older adultsi, episodic memory, executive functions, exercises, three level meta analysis, tri-nivojska meta-analiza Published in DiRROS: 03.04.2024; Views: 541; Downloads: 246 Full text (1,18 MB) This document has many files! More... |
1798. Distance deviation measure of contouring variabilityPeter Rogelj, Robert Hudej, Primož Petrič, 2013, original scientific article Abstract: Background. Several methods that are currently used for contouring analysis have problems providing reliable and/ or meaningful results. In this paper a solution to these problems is proposed in a form of a novel measure, which was developed based on requirements defined for contouring studies. Materials and methods. The proposed distance deviation measure can be understood as an extension of the closest point measures in such a way that it does not measure only distances between points on contours but rather analyse deviation of distances to both/all contours from each image point/voxel. The obtained result is information rich, reliable and provided in a form of an image, enabling detailed topographic analysis. In addition to image representation, results can be further processed into angular representation for compact topographic analysis or into overall scalar estimates for quick assessment of contour disagreement. Results. Distance deviation method is demonstrated on a multi observer contouring example with complex contour shapes, i.e., with pronounced extremes and void interior. The results are presented using the three proposed methods. Conclusions. The proposed method can detect and measure contour variation irrespective of contour complexity and number of contour segments, while the obtained results are easy to interpret. It can be used in various situations, regarding the presence of reference contour or multiple test contours. Keywords: contouring, contour comparison, distance transform Published in DiRROS: 03.04.2024; Views: 493; Downloads: 160 Full text (938,42 KB) |
1799. Ohranjanje biotske raznovrstnosti : študijska gradiva pri predmetu Ohranjanje biotske raznovrstnosti (5 vsebinskih sklopov)Lado Kutnar, 2024, other educational material Keywords: biotska raznovrstnost, ohranitvena biologija, izumiranje vrst, ravni biotske raznovrstnosti, genetska pestrost, vrstna pestrost, ekosistemska in krajinska pestrost, dejavniki ogrožanja, onesnaženje okolja, invazivne tujerodne vrste, podnebne spremembe, degradacija habitatov, fragmentacija habitatov, mehanizmi ohranjanja biotske raznovrstnosti, rdeči seznam vrst, zavarovane vrste, Natura 2000, Slovenija Published in DiRROS: 03.04.2024; Views: 519; Downloads: 0 |
1800. Effect of ionizing radiation on human skeletal muscle precursor cellsMihaela Jurdana, Maja Čemažar, Katarina Pegan, Tomaž Marš, 2013, published scientific conference contribution Abstract: Background. Long term effects of different doses of ionizing radiation on human skeletal muscle myoblast proliferation, cytokine signalling and stress response capacity were studied in primary cell cultures.Materials and methods. Human skeletal muscle myoblasts obtained from muscle biopsies were cultured and irradiated with a Darpac 2000 X-ray unit at doses of 4, 6 and 8 Gy. Acute effects of radiation were studied by interleukin - 6 (IL-6) release and stress response detected by the heat shock protein (HSP) level, while long term effects were followed by proliferation capacity and cell death.Results. Compared with non-irradiated control and cells treated with inhibitor of cell proliferation Ara C, myoblast proliferation decreased 72 h post-irradiation, this effect was more pronounced with increasing doses. Post-irradiation myoblast survival determined by measurement of released LDH enzyme activity revealed increased activity after exposure to irradiation. The acute response of myoblasts to lower doses of irradiation (4 and 6 Gy) was decreased secretion of constitutive IL-6. Higher doses of irradiation triggered a stress response in myoblasts, determined by increased levels of stress markers (HSPs 27 and 70).Conclusions. Our results show that myoblasts are sensitive to irradiation in terms of their proliferation capacity and capacity to secret IL-6. Since myoblast proliferation and differentiation are a key stage in muscle regeneration, this effect of irradiation needs to be taken in account, particularly in certain clinical conditions. Keywords: myoblasts, irradiation, proliferation, interleukin 6, muscle regeneration, apoptosis Published in DiRROS: 03.04.2024; Views: 426; Downloads: 211 Full text (377,29 KB) This document has many files! More... |