Kristina Veljkovic

Introduction: Defining an experimental configuration is a complex decision problem for early‐stage researchers, who must map goals, constraints, and requirements onto datasets, algorithms, and parameter settings that directly affect experimental outcomes. Existing scientific workflow engines improve execution and reproducibility; however, they rarely capture the decision rationale behind configuration choices, which is needed to inform future selections. Method: We propose a context‐aware decision‐support framework that formalises experiment configuration as a structured and sequential decision problem. The framework combines three components: a semantic Knowledge Graph (KG) storing historical configurations, contextual attributes, and decision rationale; an MDP‐based Option Explorer that filters the KG under user‐defined constraints and ranks feasible configurations by expected cumulative reward; and a Graphical User Interface for specifying constraints, inspecting ranked alternatives, and providing structured feedback. Unlike existing workflow systems, the framework explicitly separates user‐defined context from automated reasoning, producing an interpretable ranked list rather than a single opaque recommendation. We evaluated the framework in a user study with 90 MSc‐ and PhD‐level researchers performing a model‐selection task, using a synthetic dataset of one million experimental configurations under three levels of contextual detail. Results: Compared with manual search, the framework reduced decision time (up to 68%), reduced perceived difficulty (up to 36%), and increased user satisfaction (up to 43%) under the constrained condition. Conclusion: By formalising the link between experimental context and probabilistic decision ranking, the framework improves reproducibility and scalability of decision support in scientific experimentation.

The Republic of Srpska (RS), as a part of the Western Balkans (WB) region, has a higher diabetes prevalence than the EU. This study aims to assess the cost-effectiveness of early treatment of high-risk patients with pre-diabetes and undiagnosed diabetes in our setting. We designed a Markov chain Monte Carlo (MCMC) model which reflects the current International Diabetes Federation (IDF) three-step plan for the prevention of T2DM in those at increased risk. The model captures the evolution of the disease in FINDRISC high-risk patients from normal glucose tolerance (NGT) to impaired fasting glucose (IFG) or impaired glucose tolerance (IGT) and then to T2DM and its complications. We developed two MCMC models, in order to follow the progression of the disease in high-risk cases, ie, when early treatment is undertaken or when it is not undertaken. The health costs and quality adjusted life years (QALY) were discounted at an annual rate of 3%. The key model parameters were varied in one-way and probabilistic sensitivity analysis. Early treatment resulted in increased life expectancy, postponement of the onset of diabetes and increased QALY for all patients. The discounted incremental cost-effectiveness-ratios (ICER) in NGT, IFG, IGT, and T2DM patients were -289.9, 9724.03, -1478.59 and 4084.67 €. In high-risk IGT patients, ICER was the most favorable, being both a cost saving and QALY gaining, with the consistent results confirmed by the sensitivity analysis. The results recommend the acceptance of a new health policy of identifying IGT patients with the use of FINDRISC questionnaire and plasma glucose measurements; providing them with a lifestyle change program; and implementing intensive diabetes treatment, as their disease progresses. Our results are especially significant for the Western Balkan countries, since this was the first cost-effectiveness study of T2DM prevention in this region.

In statistical quality control, X-bar control chart is extensively used to monitor a change in the process mean. In this paper, X-bar control chart for non-normal symmetric distributions is proposed. For chosen Student, Laplace, logistic and uniform distributions of quality characteristic, we calculated theoretical distribution of standardized sample mean and fitted Pearson type II or type VII distributions. Width of control limits and power of the X-bar control chart were established, giving evidence of the goodness of fit of the corresponding Pearson distribution to the theoretical distribution of standardized sample mean. For implementation of X-bar control chart in practice, numerical example of construction of a proposed chart is given.

In context-aware decision analysis, mean can be an important measure, even when the distribution is skewed. Previous comparative studies showed that it is a real challenge to construct a confidence interval that performs well for highly skewed data. In this study, we propose new confidence intervals for the population mean based on Edgeworth expansion that include both skewness and kurtosis corrections. We compared existing and newly proposed confidence intervals for a range of samples from symmetric and skewed distributions of varying levels of kurtosis. Using Monte Carlo simulations, we evaluated the performance of these intervals based on the coverage probability, mean length, and standard deviation of the length. The proposed bootstrap Edgeworth-based confidence interval outperformed other confidence intervals in terms of coverage probability for both symmetric and skewed distributions and can be recommended for general use in practice.

Background/Aim. Given that frequent manipulation of the abutment during immediate loading can have a negative impact on the surrounding peri-implant hard and soft tissues, the concept ?one abutment at one time? (OAO) has been introduced and documented in daily clinical practice. The aim of the study was to evaluate changes in peri-implant bone levels, clinical and radiographic parameters, and patient perspectives during the six-month follow-up period. Methods. The study was designed as a randomized controlled clinical trial. Patients with bilaterally healed sites in the posterior mandible received implants with a diameter of no less than 3.5 mm and a length of at least 8 mm. Based on randomization, patients were divided into a test group and a control group. Patients who were in the test group received implants that were immediately loaded with definitive abutments. In contrast, patients in the control group received implants where healing abutments were placed, followed by temporary abutments. Implants were immediately loaded with provisional restorations within the first seven days. They were delivered over the test group?s definitive abutment and the control group?s temporary abutment. Probing depth, bleeding on probing, clinical attachment level, plaque index, and keratinized tissue width were measured. Patient-Reported Outcome Measures and the Oral Health Impact Profile - 19 (OHIP-19) questionnaires were noted. Results. Out of 24 included patients, 22 completed the six-month follow-up. Peri-implant bone loss between study groups was comparable (mesial: t = -0.798, df = 21, p = 0.434; distal: t = 1.688, df = 21, p = 0.106), without statistical inter-group significance. OHIP-19 total scores significantly decreased after three months and remained similar six months after the implant placement in both groups without statistically relevant clinical inter-group changes. Conclusion. The OAO approach and provisional abutments showed comparable effectiveness regarding the immediate loading of posterior single implants.

The purpose of this study is to analyse the effects of the Interactive Learning Materials Triangle (iLMT) on the learning and knowledge retention of 12-year-old students. The iLMT is a digital version of the standard school learning materials in Serbia, and is characterized by a high degree of interactivity and immediate feedback during the learning process. We conducted an experiment to explore whether iLMT influences student success in solving mathematical tasks that require different types of mathematical reasoning. Based on previous extensive research by Lithner, 4 types of tasks are discussed: high relatedness answer, high relatedness algorithm, local low relatedness, and global low relatedness. The study involved 633 students and 13 teachers of mathematics, equally distributed in control and test groups. The main findings indicate that student success on a knowledge test for high relatedness answer and local low relatedness tasks for the test group was significantly higher than for the control group. On the knowledge retention test, students in the test group outperformed students in the control group at high relatedness algorithm and local low relatedness tasks. Our results also suggest that, even when learning materials are carefully digitalized with the use of available technological advantages, student success in global low relatedness tasks may still be lacking.

To assess prevalence and change of depression/anxiety symptoms in spondyloarthritis patients and feasibility of depression/anxiety questionnaires. 43 Patients with axial spondyloarthritis (axSpA) and 27 patients with psoriatic arthritis (PsA) were consecutively recruited. There were 34 patients on biologics and 36 patients on nonbiologics. Patients were not previously treated for depression. The demographic variables, pain, patient global assessment, laboratory, clinical findings, diseases activity scores, Beck Depression Inventory (BDI) and Depression Anxiety and Stress Scale-short version (DASS-21) were collected. The study visits were at the beginning, after 1 month, after 3 and after 6 months. In axSpA and PsA patients on biologics, BDI and DASS-21 were significantly lower compared to nonbiologics group during time. The axSpA patients on biologics had significantly lower BDI and depression severity by BDI at each time point and lower DASS-21 after 1, 3 and 6 months. BDI in PsA patients who received biological therapy was significantly lower after 3 and 6 months. In biologics groups, BDI significantly decreased after 3 months in axSpA patients and after 1 month in PsA patients. In axSpA patients, there was a medium correlation between BDI and axial pain, patient global assessment and disease activity scores. The biological therapy significantly affected the depression/anxiety symptoms in axSpA and PsA during time. BDI moderately correlated with pain and disease activity in axSpA. BDI and DASS-21 are easy to use in daily practice.

The objective of this study was to determine the construct validity and sensitivity to change of Belgrade Ultrasound Enthesitis Score (BUSES) in spondyloarthritis patients. Seventy-six spondyloarthritis patients with enthesitis were included in this pilot, prospective, double-blinded ultrasound study. Thirty-four patients received biological and forty-two patients received non-biological therapy. BUSES was determined at the beginning, after 1, 3, and 6 months. Spearman’s correlation coefficient was calculated between BUSES and baseline characteristics. Brunner–Langer mixed non-parametric ANOVA was used to examine sensitivity to change of BUSES and effect of biological therapy on BUSES. Effect of time on the presence of each of the ultrasound enthesitis signs (increased thickness, hypoehogenicity, Power Doppler, enthesophytes, and erosions) was assessed using Cochran Q test. There was a weak, positive correlation between BUSES and disease duration, clinical enthesitis score, BASFI, BASDAI, and ASDAS-ESR/CRP. BUSES was higher at the beginning than after 1 month (p = 0.004), after 3 months (p < 0.001) and after 6 months (p < 0.001), as well as BUSES was higher after 1 month than after 3 months (p < 0.001) and after 6 months (p = 0.002). There is no difference in efficiency between non-biological and biological therapies on BUSES. Increased thickness, hypoechogenicity, and Power Doppler have decreased on Achilles tendon’s and plantar fascia’s enthesis over time. BUSES has a certain degree of construct validity because of the weak, positive correlation with parameters referring to severity of spondyloarthritis. BUSES demonstrated sensitivity to change over time due to decreasing of ultrasound acute enthesitis signs in treated spondyloarthritis patients. BUSES could be useful for monitoring the progression of enthesitis and effectiveness of the treatment.