The Sava Plain: Definition, Denomination, Delineation and Subdivison

The Sava River based its fluvial architecture compromised its upper- and lower courses. The Sava River upper course starts at Radovljica and continues downstream till Krško while from Krško till Belgrade is the Sava lower course. The Sava upper course is positioned in the mountain valley and characterized with headwaters. The Sava lower course positioned in the lowland area. The Sava Plain encompass the lowermost, almost flat surface of plain segments of the Sava valley and lower plain segments of its tributaries. The Sava Plain surface geology composed of Holocene fluvial, as well as Pleistocene alluvial and eolian sediments. According to the Holocene fluvial architecture of the Sava river three significant parts can be defined as the Krško-Samobor Plain, the Upper- and the Lower Sava Plain. The Upper Sava valley represents the Krško-Samobor Basin from Krško downstream till the Podsused Gate. The Upper Sava Plain covers the Sava plain in between Podsused Gate downstream to the Slavonski- and Bosanski Brod or the Brod Gate. The Lower Sava Plain ascends from Brod Gate downstream till the mouth of the Sava to the Danube in Belgrade. The Krško-Podsused Plain and the Upper Sava Plain channel planform type characterized with the gentle meandering river architecture its area composed of Holocene fluvial sediments, while the Lower Sava Plain with meandering river architecture of Pleistocene fluvial and eolian sediments and Holocene fluvial sediments

Efficient "black-box" multigrid solvers for convection-dominated problems

The main objective of this project is to develop a "black-box" multigrid preconditioner for the iterative solution of finite element discretisations of the convection-diffusion equation with dominant convection. This equation can be considered a stand alone scalar problem or as part of a more complex system of partial differential equations, such as the Navier-Stokes equations. The project will focus on the stand alone scalar problem. Multigrid is considered an optimal preconditioner for scalar elliptic problems. This strategy can also be used for convection-diffusion problems, however an appropriate robust smoother needs to be developed to achieve mesh-independent convergence. The focus of the thesis is on the development of such a smoother. In this context a novel smoother is developed referred to as truncated incomplete factorisation (tILU) smoother. In terms of computational complexity and memory requirements, the smoother is considerably less expensive than the standard ILU(0) smoother. At the same time, it exhibits the same robustness as ILU(0) with respect to the problem and discretisation parameters. The new smoother significantly outperforms the standard damped Jacobi smoother and is a competitor to the Gauss-Seidel smoother (and in a number of important cases tILU outperforms the Gauss-Seidel smoother). The new smoother depends on a single parameter (the truncation ratio). The project obtains a default value for this parameter and demonstrated the robust performance of the smoother on a broad range of problems. Therefore, the new smoothing method can be regarded as "black-box". Furthermore, the new smoother does not require any particular ordering of the nodes, which is a prerequisite for many robust smoothers developed for convection-dominated convection-diffusion problems. To test the effectiveness of the preconditioning methodology, we consider a number of model problems (in both 2D and 3D) including uniform and complex (recirculating) convection fields discretised by uniform, stretched and adaptively refined grids. The new multigrid preconditioner within block preconditioning of the Navier-Stokes equations was also tested. The numerical results gained during the investigation confirm that tILU is a scalable, robust smoother for both geometric and algebraic multigrid. Also, comprehensive tests show that the tILU smoother is a competitive method.EThOS - Electronic Theses Online ServiceEPSRCGBUnited Kingdo

Parallel block preconditioning for multi-physics problems

In this thesis we study efficient parallel iterative solution algorithms for multi-physics problems. In particular, we consider fluid structure interaction (FSI) problems, a type of multi-physics problem in which a fluid and a deformable solid interact. All computations were performed in Oomph-Lib, a finite element library for the simulation of multi-physics problems. In Oomph-Lib, the constituent problems in a multi-physics problem are coupled monolithically, and the resulting system of non-linear equations solved with Newton's method. This requires the solution of sequences of large, sparse linear systems, for which optimal solvers are essential. The linear systems arising from the monolithic discretisation of multi-physics problems are natural candidates for solution with block-preconditioned Krylov subspace methods.We developed a generic framework for the implementation of block preconditioners within Oomph-Lib. Furthermore the framework is parallelised to facilitate the efficient solution of very large problems. This framework enables the reuse of all of Oomph-Lib's existing linear algebra infrastructure and preconditioners (including block preconditioners). We will demonstrate that a wide range of block preconditioners can be seamlessly implemented in this framework, leading to optimal iterative solvers with good parallel scaling.We concentrate on the development of an effective preconditioner for a FSI problem formulated in an arbitrary Lagrangian Eulerian (ALE) framework with pseudo-solid node updates (for the deforming fluid mesh). We begin by considering the pseudo-solid subsidiary problem; the deformation of a solid governed by equations of large displacement elasticity, subject to a prescribed boundary displacement imposed with Lagrange multiplier. We present a robust, optimal, augmented-Lagrangian type preconditioner for the resulting saddle-point linear system and prove analytically tight bounds for the spectrum of the preconditioned operator with respect to the discrete problem size.This pseudo-solid preconditioner is incorporated into a block preconditioner for the full FSI problem. One key feature of the FSI preconditioner is that existing optimal single physics preconditioners (such as the well known Navier-Stokes Least Squares Commutator preconditioner) can be employed to approximately solve the linear systems associated with the constituent sub-problems. We evaluate its performance on selected 2D and 3D problems. The preconditioner is optimal for most problems considered. In cases when sub-optimality is detected, we explain the reasons for such behavior and suggest potential improvements.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Probiotics in Allergic Diseases

Allergic diseases are the most common chronic diseases in children and no complete agreement on effective measures for primary prevention is available. Atopic family history is one of the most important risk factors for the development of asthma. A decline in microbial diversity due to modern lifestyle particularly in urban areas was proposed to have an important role in allergic epidemic. Recent studies are more focused on the specific mode of prevention such as probiotic usage in early pregnancy and infants period. It is well known that the composition of the gastrointestinal microbiota has been postulated to play a role in the development of allergies because it promotes potentially antiallergenic processes: TH1-type immunity, generation of TGF (which has an essential role in suppression of TH2-induced allergic inflammation and induction of oral tolerance), and IgA production, an essential component of mucosal immune defenses. Probiotic interventions administered during pregnancy and breastfeeding offer a unique opportunity to influence a range of important maternal and infant outcomes

Intracranial – extracranial meningioma: A case report of a rare entity

Meningiomas are common benign intracranial tumors. However, intracranial meningiomas with extracranial extension are exceedingly rare lesions with only a few reported cases in the literature. We report a case of an 86 years old female patient presented with enlarging mass over left parietal region for last 3 years. Besides cosmetic, she had no complaints. Head CT scan with bone window showed a large tumor consisting of intracranial and extracranial part, suggestive for meningioma. Patient was operated, and both parts of tumor were removed. Taking into account surgery indication and patient’s age, bone flap was returned. The postoperative course was uneventful and patient fully recovered. In the case of epicranial tumor attached to the underlying bone, meningioma should be excluded

Health-related quality of life in elderly patients hospitalized with chronic heart failure

Background: Chronic heart failure is a very common condition in the elderly, characterized not only by high mortality rates, but also by a strong impact on health-related quality of life (HRQOL). Previous studies of HRQOL in elderly heart failure subjects have included mostly outpatients, and little is known about determinants of HRQOL in hospitalized elderly population, especially in Serbia. In this study, we tried to identify factors that influence HRQOL in elderly patients hospitalized with chronic heart failure in Serbia. Methods: The study population consisted of 136 patients aged 65 years or older hospitalized for chronic heart failure. HRQOL was assessed using the Minnesota Living with Heart Failure questionnaire. Predictors of HRQOL were identified by multiple linear regression analysis. Results: Univariate analysis showed that patients with lower income, a longer history of chronic heart failure, and longer length of hospital stay, as well as those receiving aldosterone antagonists and digoxin, taking multiple medications, in a higher NYHA class, and showing signs of depression and cognitive impairment had significantly worse HRQOL. Presence of depressive symptoms (P<0.001), higher NYHA class (P=0.021), lower income (P=0.029), and longer duration of heart failure (P=0.049) were independent predictors of poor HRQOL. Conclusion: Depressive symptoms, higher NYHA class, lower income, and longer duration of chronic heart failure are independent predictors of poor HRQOL in elderly patients hospitalized with chronic heart failure in Serbia. Further, there is an association between multiple medication usage and poor HRQOL, as well as a negative impact of cognitive impairment on HRQOL. Hence, measures should be implemented to identify such patients, especially those with depressive symptoms, and appropriate interventions undertaken in order to improve their HRQOL.publishedVersio

Adherence to the 4S-AF Scheme in the Balkan region:insights from the BALKAN-AF survey

BackgroundThe 4S-AF scheme includes stroke risk, symptoms, severity of burden, and substrate severity domain.AimWe aimed to assess the adherence to the 4S-AF scheme in patients classified according to stroke risk in post hoc analysis of the BALKAN-AF dataset.MethodsA 14-week prospective enrolment of consecutive patients with electrocardiographically documented atrial fibrillation (AF) was performed in seven Balkan countries from 2014 to 2015.ResultsLow stroke risk (CHA2DS2-VASc score, 0 in males or 1 in females) was present in 162 (6.0%) patients. 2 099 (77.4%) patients had CHA2DS2-VASc score ≥3 in females or ≥2 in males (high stroke risk), and 613 (22.6%) had CHA2DS2-VASc score ConclusionsOAC overuse was observed in patients with low stroke risk, whilst OAC underuse was evident in those with high risk of stroke. The percentage of highly symptomatic patients with high risk of stroke who were offered a rhythm control strategy was low