Efficacy and limitations of ChatGPT as a biostatistical problem-solving tool in medical education in Serbia: a descriptive study

Purpose This study aimed to assess the performance of ChatGPT (GPT-3.5 and GPT-4) as a study tool in solving biostatistical problems and to identify any potential drawbacks that might arise from using ChatGPT in medical education, particularly in solving practical biostatistical problems. Methods ChatGPT was tested to evaluate its ability to solve biostatistical problems from the Handbook of Medical Statistics by Peacock and Peacock in this descriptive study. Tables from the problems were transformed into textual questions. Ten biostatistical problems were randomly chosen and used as text-based input for conversation with ChatGPT (versions 3.5 and 4). Results GPT-3.5 solved 5 practical problems in the first attempt, related to categorical data, cross-sectional study, measuring reliability, probability properties, and the t-test. GPT-3.5 failed to provide correct answers regarding analysis of variance, the chi-square test, and sample size within 3 attempts. GPT-4 also solved a task related to the confidence interval in the first attempt and solved all questions within 3 attempts, with precise guidance and monitoring. Conclusion The assessment of both versions of ChatGPT performance in 10 biostatistical problems revealed that GPT-3.5 and 4’s performance was below average, with correct response rates of 5 and 6 out of 10 on the first attempt. GPT-4 succeeded in providing all correct answers within 3 attempts. These findings indicate that students must be aware that this tool, even when providing and calculating different statistical analyses, can be wrong, and they should be aware of ChatGPT’s limitations and be careful when incorporating this model into medical education

Legislative framework regarding wastewater treatment in the Republic of Serbia and flow and transport modelling in the determination on effluent quality of wastewater treatment plant of Belgrade central sewerage system

The largest sewerage system in Belgrade is Belgrade Central Sewerage System, which covers the area of about 85% of the sewerage network, with about 1,250,000 inhabitants connected to the sewage infrastructure. The interaction of emission limit values, environmental quality standards, wastewater, effluent and recipient characteristic flows and qualities from the standpoint of environmental impact in the unfavorable environmental conditions was modelled to define the level of wastewater treatment at future Belgrade Central Sewerage System wastewater treatment plant

In vitro testing of genotoxic and apoptotic potential of two synthesized nanomaterials by DNA fragmentation assay

Nanomaterials represent a relatively new and developing class of materials that are widely used because of their unique mechanical and physiochemical properties. Due to the particles’ size and the ability to easily enter the cells and interact with different cellular components, nanoparticles can exhibit toxic effects in biological systems, so it is necessary to conduct a thorough in vitro biocompatibility testing. Our aim was to examine the in vitro genotoxic and apoptotic potential of two different synthesized nanomaterials intended for bone tissue engineering and regenerative applications: biphasic calcium phosphate coated with poly- D,L-lactide-co-glycolide (CP/PLGA) and cobalt-substituted hydroxyapatite (CoHAp), by DNA fragmentation assay. NB4 cells (acute promyelocytic leukemia cell line) were incubated with different concentrations of CP/PLGA and CoHAp nanomaterials for 24 hours. Cells cultured in standard medium, without nanomaterials, were used as negative control and cells treated with hydrogen peroxide were used as positive control. After incubation with materials the genomic DNA was extracted from the cells and applied on horizontal agarose gel electrophoresis. The results of DNA fragmentation assay were observed on gel documentation system. Higher examined concentrations of CP/PLGA caused DNA fragmentation at some extent with DNA laddering at approximately 180 bp which is characteristic for later stages of apoptosis, while DNA laddering was not seen in the case of CoHAp at the same concentrations. Although both materials are in the form of nanoparticles, a different effect in apoptotic DNA fragmentation was observed which suggests that the chemical composition of nanomaterials notably affects the genotoxicity and apoptosis potential in addition to the particle size

Dynamics resilience as a measure for risk assessment of the complex water systems: Project overview

To manage impacts of natural disasters we propose the use of system approach to enhance the predictive power in resilience assessment of water system beyond the largest recorded events. The main objective of the proposed research is the development of a modelling framework for dynamic resilience assessment. The traditional risk-based approach and use of standards is replaced with a quantitative assessment of the dynamic resilience. By developing a novel framework, the research therefore makes a context introducing a dynamic resilience as a measure for risk assessment. In this context, the research will provide the generic methodology and tools for dynamic resilience assessment. This framework offers an opportunity for highlighting the role of using multi-model simulations which supports the estimation of dynamic resilience. It underpins investment decisions within the different sectors (e.g. water, hydroenergy, environmental sectors) for adaptation schemes under the uncertain changes in our environment (e.g. variable climate, natural disasters)

Dinamička rezilijentnost kao mera za upravljanje rizikom kod složenih vodoprivrednih sistema: Implementacija modela otkaza u vodoprivredni model

Održivo upravljanje složenim vodoprivrednim sistemima, u neizvesnim i promenljivim klimatskim uslovima, kao i pod rastućim socio-ekonomskim zahtevima i ograničenjima, predstavlja kompleksan izazov. Samo u poslednjih par decenija, zabeležene su katastrofalne prirodne nepogode (poplave, suše, zemlotresi itd) koje su po intezitetu prevazilazile dosad zabeležene vrednosti. Vodoprivredni sistemi, kao što su višenamenske akumulacije, predstavljaju jedan primer vitalnih sistema čije je pouzdano funkcionisanje dodatno ugroženo u svetlu novih okolnosti. Kvantifikovanje „spremnosti“ sistema na navedene događaje, se uobičajeno sprovodi kroz analizu rizika primenom tradicionalnih statičkih veličina. Kako statičke mere imaju izvesna ograničenja, u poslednje vreme, sve više se koristi koncept dinamičke rezilijentnosti (izdržljivosti). Kako bi se obezbedila minimizacija štetnog uticaja navedenih događaja na funkcionalnost vodoprivrednih sistema, neophodno je povećati tzv. „rezilijentnost“ sistema, odnosno sposobnost sistema da izdrži i prihvati neki poremećaj i povrati pređašnju funkcionalnost. Kako bi se ispitala „spremnost“ sistema na razne nepovoljne scenarije, koji podrazumevaju smanjenje funkcionalnosti različitih komponenata sistema, neophodno je koristiti adekvatan simulacioni model vodoprivrednog sistema i model otkaza. Na osnovu ovih modela moguće je proceniti ponašanje sistema nakon širokog spektra mogućih nepovoljnih događaja. Takođe, moguće je detektovati komponente koje bi uz pravovremeno ulaganje i poboljšanje stanja ublažile pad funkcionalnosti sistema pri različitim poremećajima i povećale rezilijentnost celog sistema. U ovom istraživanju predstavljen je pristup za modeliranje otkaza i implementaciju istih u vodoprivredni model. Kao primer korišćen je vodoprivredni sistem Pirot

Quantifying Multi-Parameter Dynamic Resilience for Complex Reservoir Systems Using Failure Simulations: Case Study of the Pirot Reservoir System

The objective of this research is to introduce a novel framework to quantify the risk of the reservoir system outside the design envelope, taking into account the risks related to flood-protection and hydro-energy generation under unfavourable reservoir element conditions (system element failures) and hazardous situations within the environment (flood event). To analyze water system behavior in adverse conditions, a system analysis approach is used, which is founded upon the system dynamics model with a causal loop. The capability of the system in performing the intended functionality can be quantified using the traditional static measures like reliability, resilience and vulnerability, or dynamic resilience. In this paper, a novel method for the assessment of a multi-parameter dynamic resilience is introduced. The multi-parameter dynamic resilience envelops the hydropower and flood-protection resilience, as two opposing demands in the reservoir operation regime. A case study of a Pirot reservoir, in the Republic of Serbia, is used. To estimate the multi -parameter dynamic resilience of the Pirot reservoir system, a hydrological model, and a system dynamic simulation model with an inner control loop, is developed. The inner control loop provides the relation between the hydropower generation and flood-protection. The hydrological model is calibrated and generated climate inputs are used to simulate the long-term flow sequences. The most severe flood event period is extracted to be used as the input for the system dynamics simulations. The system performance for five different scenarios with various multi failure events (e.g., generator failure, segment gate failure on the spillway, leakage from reservoir and water supply tunnel failure due to earthquake) are presented using the novel concept of the explicit modeling of the component failures through element functionality indicators. Based on the outputs from the system dynamics model, system performance is determined and, later, hydropower and flood protection resilience. Then, multi-parameter dynamic resilience of the Pirot reservoir system is estimated and compared with the traditional static measures (reliability). Discrepancy between the drop between multi-parameter resilience (from 0.851 to 0.935) and reliability (from 0.993 to 1) shows that static measure underestimates the risk to the water system. Thus, the results from this research show that multi-parameter dynamic resilience, as an indicator, can provide additional insight compared to the traditional static measures, leading to identification of the vulnerable elements of a complex reservoir system. Additionally, it is shown that the proposed explicit modeling of system components failure can be used to reflect the drop of the overall system functionality

A Novel Two-Step Electrochemical Deposition Method for Sn-Pd Electrocatalyst Synthesis for a Potential Application in Direct Ethanol Fuel Cells

Sn-Pd electrocatalysts with a constant atomic ratio of 60 at.% Sn‒40 at.% Pd suitable for potential application in direct ethanol fuel cells were synthesized using a novel two-step electrodeposition method. First, Sn was electrodeposited in various forms of dendrites, from spear-like and needle-like to individual fern-like dendrites to a network of intertwined fern-like dendrites, by varying the cathodic potential and then performing electrodeposition of Pd at a constant current density in the second step. A morphological and elemental analysis of Sn and Sn-Pd electrocatalysts was performed using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) techniques, while the size of Sn dendrites was analyzed using the particle size distribution (PSD) method. Cyclic voltammetry (CV) and chronoamperometry were applied in order to study the catalytic behavior of Sn-Pd electrocatalysts in the ethanol oxidation reaction (EOR), while CO stripping was used to estimate the antipoisoning capability of the electrocatalysts. The Sn surface morphology of the sub-layer was highly correlated with the electrocatalytic activity of the examined Sn-Pd electrocatalysts. The high activity it presented towards the EOR showed the suitability of the Sn-Pd electrocatalyst constructed from individual fern-like Sn dendrites as a sub-layer. Compared to Pd alone, this Sn-Pd catalyst showed more than 3 times higher activity and improved EOR kinetics. This enhancement in the catalytic activity of the Sn-Pd electrocatalysts is attributed to both the morphological characteristics of Sn as a sub-layer and the bifunctional effect

DETERMINATION OF OPTIMAL CONTOURS OF OPEN PIT MINE DURING OIL SHALE EXPLOITATION, BY MINEX 5.2.3. PROGRAM

By examination and determination of optimal solution of technological processes of exploitation and oil shale processing from Aleksinac site and with adopted technical solution and exploitation of oil shale, derived a technical solution that optimize contour of the newly defined open pit mine. In the world, this problem is solved by using a computer program that has become the established standard for quick and efficient solution for this problem. One of the computer’s program, which can be used for determination of the optimal contours of open pit mines is Minex 5.2.3. program, produced in Australia in the Surpac Minex Group Pty Ltd Company, which is applied at the Mining and Metallurgy Institute Bor (no. of licenses are SSI - 24765 and SSI - 24766). In this study, authors performed 11 optimization of deposit geo - models in Minex 5.2.3. based on the tests results, performed in a laboratory for soil mechanics of Mining and Metallurgy Institute, Bor, on samples from the site of Aleksinac deposits

Model analysis of bucket wheel excavator SchRs 630 strength

The possibilities of testing real constructions are often limited, especially in case of large constructions. The idea of model testing is to create a sub-scaled model in order to anticipate the behavior of the real construction, regarding the behavior of the model, with sufficient accuracy. The aim of this paper is to demonstrate that model testing of bucket wheel excavator structure, from the aspect of the strength of the constructions, is possible. In order to prove this assumption, firstly, numerical calculations of a real construction and its sub-scaled model were performed using the Finite Element Method. Sub-scaled structure is 10 times scaled real structure (in size and plates thickness). Within the static calculation, the analysis of the stress mapping from sub-scaled model to real structure was carried out, by partial groups of construction. The coefficients connecting stresses of sub-scaled model and stresses of real construction were formulated. Dynamic calculations of sub-scaled model and real structure were also performed. Then, a physical model was produced and subjected to experimental testing. Experimental testing was performed in order to verify the numerical models. A parallel testing of the model with strain gauges and a system for non-contact measurement of displacement and deformation was performed. High matching results were obtained of two experimental methods on one side, and numerical calculation on the other side. The physical model and the successful experiments carried out on it confirmed that these structures can be subjected to model testing, without important constraints and with sufficient accuracy

Model analysis of bucket wheel excavator SchRs 630 strength

The possibilities of testing real constructions are often limited, especially in case of large constructions. The idea of model testing is to create a sub-scaled model in order to anticipate the behavior of the real construction, regarding the behavior of the model, with sufficient accuracy. The aim of this paper is to demonstrate that model testing of bucket wheel excavator structure, from the aspect of the strength of the constructions, is possible. In order to prove this assumption, firstly, numerical calculations of a real construction and its sub-scaled model were performed using the Finite Element Method. Sub-scaled structure is 10 times scaled real structure (in size and plates thickness). Within the static calculation, the analysis of the stress mapping from sub-scaled model to real structure was carried out, by partial groups of construction. The coefficients connecting stresses of sub-scaled model and stresses of real construction were formulated. Dynamic calculations of sub-scaled model and real structure were also performed. Then, a physical model was produced and subjected to experimental testing. Experimental testing was performed in order to verify the numerical models. A parallel testing of the model with strain gauges and a system for non-contact measurement of displacement and deformation was performed. High matching results were obtained of two experimental methods on one side, and numerical calculation on the other side. The physical model and the successful experiments carried out on it confirmed that these structures can be subjected to model testing, without important constraints and with sufficient accuracy