Analysis Method Research Articles

Adaptive algorithms for drone flight control under communication constraints and information incompleteness

Abstract With the rapid increase in the use of drones in various applications, including commercial and governmental, and the increasing probability of communication failures and contingencies, research becomes critical to ensure the safety and efficiency of their operations. The aim of this research is to develop adaptive drone flight control algorithms capable of operating effectively under conditions of limited communication and incomplete information to ensure reliable and safe autonomous operation of these systems. The applied methods include computer modelling and simulation, analytical, statistical, functional, deductive and descriptive methods. The study found that the use of performance evaluation methods for complex systems enables the identification of safety and performance criteria for drones, and drone flight control provides basic principles and methods that can be adapted for drones, including autopiloting and navigation. In addition, analyses of satellite communication and navigation prove the need to consider the limitations of this technology when developing drone control algorithms. The combination of these techniques allows for more robust and adaptive drone control systems that can function effectively in complex environments such as communication limitations and incomplete information. Additionally, it was found that the integration of adaptive control algorithms based on these methods allows drones to effectively adapt to variable environmental conditions and make decisions quickly even when communication is lost or information is limited.

HOW NOT TO DO EUROPEAN INTEGRATIONS: BOSNIA AND HERZEGOVINA AND LEGAL CHALLENGES IN ACCESSION PROCESS TO EUROPEAN UNION

Background: Bosnia and Herzegovina, with its complex constitutional and legal system, is facing many difficulties in its progress toward European Union membership. These challenges have been worsened by political instability, exacerbated by geopolitical shifts in Europe following Russian aggression on Ukraine. Legal complexities in the constitutional order of Bosnia and Herzegovina are often used to halt the country's progress and divert it from its European trajectory. This article analyses the specific instances of very unfavourable legal solutions that are hindering the EU accession process, as well as the recommendations put forth by the EU Commission aimed at removing these legal obstacles. There is an urgent need for reform of constitutional and legal rules to enable the country to effectively continue its EU accession path. The importance of the EU membership perspective for Bosnia and Herzegovina extends beyond simply joining a desirable club of prosperous countries; the reforms required during the EU accession process are needed to strengthen the efficiency of state institutions and secure lasting peace in the country and region. As such, the urgency and potential impact of these proposed legislative changes cannot be overstated. Methods: The research primarily employs a combination of analytical, normative, and comparative methods to examine the legal system and chronology of the integration process. The legal historical method is also used where appropriate. The research focuses on the content of constitutional norms, relevant legislative acts in Bosnia and Herzegovina, and legislative acts of the European Union and other countries. These legislative acts are compared with EU recommendations and legislation from other EU member states to identify the discrepancies. The article provides an overview of the legal framework governing EU integrations in Bosnia and Herzegovina, including norms of international law, constitutional law, national legislation, and EU law that are negatively impacting the EU accession process, and offers certain recommendations for their improvement. Results and conclusions: The research has identified certain norms of constitutional and legislative origin in the legal system of Bosnia and Herzegovina that are harming the country's ability to effectively engage in the EU accession process. Through a normative approach, the article gives recommendations for their improvement, which are in line with the standards set by the institutions of the EU. Amending these problematic legal frameworks would remove their use as political tools aimed at halting the country’s progress in the EU integrations.

Development and Validation of a Stability Indicating Analytical Method for the Estimation of Gliclazide and Sitagliptin in Bulk Drugs and Tablet Dosage Forms by RP-UPLC: An Application of the Quality-by-Design Approach

Sitagliptin and gliclazide are the active ingredients in OpdualagTM. A highly selective DPP-4 inhibitor, sitagliptin is thought to work in type 2 diabetics by delaying the inactivation of incretin hormones, which increases their concentration and lengthens their duration of effect. Sulfonyl urea mostly enhances insulin secretion from pancreatic β-cells by inhibiting ATP-sensitive K+ channels, leading to depolarisation and Ca2+ influx. Reduced serum glucagon levels and enhanced insulin binding to receptors and target tissues are the mechanisms by which it exerts its effects. Objective: This study aims to create and evaluate an RP-UPLC technique for the detection of sitagliptin and gliclazide in pharmaceutical products by applying AQbD principles. Method: Findings By utilising the Design-expert® programme, we were able to execute a central composite design (CCD) consisting of three components arranged in five distinct layers, which greatly improved the chromatographic conditions. One method that oversees the whole analytical procedure life cycle—from method design and optimisation to validation and continual improvement—is Analytical Quality by Design (AQbD). Results: The retention times for sitagliptin were 1.269 minutes and for gliclazide they were 1.572 minutes. The limits of detection (LOD) and quantitation (LOQ) for Sitagliptin and Gliclazide were 0.19 µg/mL, 0.56 µg/mL, 0.28 µg/mL, and 0.86 µg/mL respectively. The recovery percentages for sitagliptin and gliclazide were found to be 99.15% to 100.54% and 99.93% to 100.58%, respectively. Both drugs were found to be susceptible to oxidative and photolytic breakdown in the forced degradation studies. Conclusions A novel RP-UPLC method has been developed for the quantitative detection of sitagliptin and gliclazide in pharmaceutical formulations, utilising the AQbD-based methodology. This approach is straightforward, rapid, precise, particular, and stable-indicating.

Plant-Derived and Synthetic Nicotine in E-Cigarettes: Is Differentiation with NMR Spectroscopy Possible?

To circumvent regulatory frameworks, many producers start to substitute plant-derived nicotine (tobacco-derived nicotine, TDN) by synthetic nicotine (tobacco-free nicotine, TFN) in e-cigarette products. Due to the higher costs of enantiomeric synthesis and purification of TFN, there is a need to develop an analytical method that clearly distinguishes between the two sources. To trace nicotine's origin, its enantiomeric purity can be postulated by 1H NMR spectroscopy using (R)-(-)-1,1'-binaphthyl-2,2'-diyl hydrogen phosphate (BNPPA) as a chiral complexing agent. Low-field (LF) NMR conditions were optimized for this purpose even using a small amount of e-liquid sample (limit of quantification 8 mg/mL nicotine). All investigated products were found to contain one isomer (most likely (S)-(-)-nicotine). A direct 13C NMR method at natural abundance has been validated to differentiate (S)-TDN and (S)-TFN in e-cigarettes produced using nicotine of different origin. The method is based on calculation of the relative 13C content of 10 C-positions of the nicotine molecule with intraday and interday precisions below <0.2%. The method was applied to 12 commercial e-cigarette products labeled as containing TDN and TFN. Principal component analysis (PCA) was applied to the relative peak areas to visualize the difference between studied products. The LF 1H NMR method is a good alternative to expensive high-field NMR to differentiate between a racemate mixture and single optical isomers, whereas only high-precision 13C NMR can be used to distinguish (S)-TDN and (S)-TFN in e-cigarettes after appropriate sample extraction.

EXTRACTION, Extraction, Isolation, Identification and Estimation of Diosgenin by TLC Profiling and UHPLC-LC-SRM Analysis in Three Costus Species

Medicinal plants are utilized for treating many ailments, since ancient times due to their tremendous therapeutic properties. The plant derivatives are used as a raw material for the synthesis of drugs either as a natural or artificial synthetic drug. Costaceae family members are known to possess many medicinal properties few of them are mainly consumed to reduce the blood glucose level and treat many disorders. The sapogenin contained in the rhizome of three Costus species was extracted, identified, and characterized. Young rhizomes were harvested surface sterilized, hydrolyzed; extracted through a soxhlet apparatus and concentrated fractions were subjected to a preliminary phytochemical screening test for saponin, Thin Layer Chromatography, and the UHPLC-MS SRM analysis. The result showed that the maximum yield of the Diosgenin was obtained from the chloroform extract of Costus speciosus. The pharmaceutical analysis in all the three Costus species carried out with isolated saponin was compared with standard Diosgenin. The characterization of isolated diosgenin was done by UHPLC MS and SRM, based on the retention time of all three samples and the comparison with standard Diosgenin. Isolated Diosgenin was quantified through thin layer chromatography with n-hexane: ethyl acetate (7:3) as mobile phase at Rf value of 0.48. The amount of Isolated Diosgenin was estimated by comparing the peak area at a retention time Rt value of 8.5 in all the samples and compared with standard Diosgenin high amount of Diosgenin was found in Costus speciosus rhizome followed by Costus igneus and Costus pictus. The preliminary phytochemical screening and analytical methods involved during the present study were found satisfactory. Thus, the protocol can be used for the extraction of Diosgenin and further used in the synthesis of Drugs. Keywords: Costus pictus, Costus speciosus, Costus igneus, rhizome, TLC, UHPLC-MS, SRM

Enantiomer-Specific Stable Carbon and Nitrogen Isotopic Analyses of Underivatized Individual l- and d-Amino Acids by HPLC + HPLC Separation and Nano-EA/IRMS.

We developed a new method for stable carbon and nitrogen isotopic (δ13C and δ15N) analysis of underivatized amino acid (AA) enantiomers simultaneously, based on high-performance liquid chromatography (HPLC) separation and off-line isotopic measurement. l- and d-Enantiomers of each AA were isolated using a ReproSil Chiral-AA column, purified by wet chemical procedure, and analyzed for δ13C and δ15N values with a nanomol-scale elemental analyzer/isotope-ratio mass spectrometry (nano-EA/IRMS) system. We successfully achieved the separation of l- and d-enantiomers of 15 proteinogenous AAs, with all l-enantiomers eluting before respective d-enantiomers. The δ13C and δ15N values of AA enantiomers were consistent before and after HPLC separation, demonstrating that this analytical method conserves isotopic information. By coupling this column with a multidimensional HPLC system for isolating individual AAs, we analyzed l- and d-AAs in a natural sample, peptidoglycan isolated from Gram-positive bacterium Bacillus subtilis. Results show a surprisingly large 15N-depletion, up to 20‰, in d-glutamic acid relative to its l-counterpart. The first example, to our knowledge, of δ13C and δ15N analyses of underivatized AA enantiomers is expected to contribute to various research areas in the future.

Brain-wide alterations revealed by spatial transcriptomics and proteomics in COVID-19 infection.

Understanding the pathophysiology of neurological symptoms observed after severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection is essential to optimizing outcomes and therapeutics. To date, small sample sizes and narrow molecular profiling have limited the generalizability of findings. In this study, we profiled multiple cortical and subcortical regions in postmortem brains of patients with coronavirus disease 2019 (COVID-19) and controls with matched pulmonary pathology (total n = 42) using spatial transcriptomics, bulk gene expression and proteomics. We observed a multi-regional antiviral response without direct active SARS-CoV2 infection. We identified dysregulation of mitochondrial and synaptic pathways in deep-layer excitatory neurons and upregulation of neuroinflammation in glia, consistent across both mRNA and protein. Remarkably, these alterations overlapped substantially with changes in age-related neurodegenerative diseases, including Parkinson's disease and Alzheimer's disease. Our work, combining multiple experimental and analytical methods, demonstrates the brain-wide impact of severe acute/subacute COVID-19, involving both cortical and subcortical regions, shedding light on potential therapeutic targets within pathways typically associated with pathological aging and neurodegeneration.

Reflection phenomena of thermoelastic plane waves on a rigid surface within a size-dependent elastic media

The current investigation aims to comprehend the spread of time-harmonic thermoelastic plane waves in an isotropic and homogeneous nonlocal elastic material without bounds, within the framework of the Lord–Shulman model and Eringen’s nonlocal stress model. Our analysis reveals two sets of coupled longitudinal waves and one independent shear-type wave. The coupled longitudinal waves experience dispersion and damping over time due to the dissipative nature of the L-S model. In contrast, the vertically shear-type waves exhibit dispersion characteristics due to the presence of nonlocality in the medium. Furthermore, we observe that the shear-type wave encounters a critical frequency, while the coupled longitudinal waves may face critical frequency conditions under certain circumstances. We explore the reflection of thermoelastic waves at a rigid, thermally insulated, and isothermal boundary of a thermoelastic half-space, particularly in the case of an incident coupled longitudinal thermoelastic wave. We determine the amplitude ratios of the reflected waves to the incident wave through analytical methods. For a specific model, we generate various graphs to analyze the behavior of phase speeds, attenuation coefficients, and reflection coefficients. To assess the impact of the elastic nonlocal parameter on the variations of phase speeds, attenuation coefficients, and amplitude ratios of the reflected waves, we present graphical representations. Notably, our observations indicate that all waves are influenced by the nonlocality of the medium. Longitudinal waves exhibit sensitivity to thermal parameters, whereas the shear-type wave remains independent of thermal effects. Furthermore, the presence of elastic nonlocality results in a reduction in the classical shear-type wave speed.

Crystalline deposit in lichens: Determination of crystals with regard to practical application in standard taxonomic studies

The presence of various crystal forms is quite often noticed in lichens from manytaxonomic groups. The crystalline deposit may be linked with the production of secondary metabolites or metal oxalates as well as to the uptake of calcium carbonate from the host substrate. Although the crystals are clearly visible under a microscope employing polarized light, their detailed determination is very difficult without the use of specialized equipment and analytical methods. On the other hand, it is not uncommon for the surface of lichen thalli to be covered with apparent pruina, which is formed by masses of calcium oxalate crystals. Regardless of their origin and distribution, crystalline products can perform an important functional role and enhance the adaptation of a given species to a specific habitat. Moreover, the presence and kind of crystals can be species-specific or characteristic of a certain group of species and, therefore, may constitute a useful diagnostic feature. We intended to examine the extent to which standard methods used in lichen taxonomy, such as solubility tests in chemical reagents, allow for the basic determination of crystals. We indicate the basic differences between various crystal deposits that can be observed inside or outside the lichen thallus. The presented results are based on examining selected specimens representing various lichen genera.

The New Paradigm of Russia’s International Financial Relations

The objective of this study is to explore the fundamental features of the emerging international financial framework in Russia, to pinpoint potential risks and central issues in its development. The distinctive characteristics of Russian companies’ international trade activities are explored through a comparative and economic-statistical analysis. The identification of risks was done by creating checklists using logical and analytical methods to organize information about the research topic. The risk analysis was based on the Ishikawa method (“fish bone”). The framework of Russia’s international financial interactions from 1991 to 2014 was centred on the goal of swiftly integrating the country into the global monetary and financial framework, fully embracing the standards set by the global power, while also acknowledging the increasing reliance on the collective West, which could potentially compromise national interests. The New Paradigm envisions a balanced integration of diverse subsystems and individual components — nations and groups of nations — within a cohesive geographical context. This framework envisions the enhancement of mutually beneficial international collaboration with allied nations and the development of novel settlement and payment systems, which are based on the utilization of national currencies and/or cutting-edge digital instruments.

Environmentally friendly screen-printed electrodes for the selective detection of 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in forensic analysis.

In response to the growing need for sustainable analytical methods, this study explores the repurposing of screen-printed electrodes (SPEs) that would otherwise be discarded. This involves recoating the working electrode surface with a graphite (Gr) and chitosan (CTS) dispersion, creating a reusable SPE (SPE-Gr/CTS). Demonstrating its utility, SPE-Gr/CTS was employed for the detection of 4-bromo-2,5-dimethoxyphenethylamine (2C-B), a phenylethylamine commonly used for recreational proposes. Identifying 2C-B in fluid oral and seized samples is of great interest for forensic and toxicological applications. The 2C-B detection using SPE-Gr/CTS was optimized in Britton-Robinson buffer solution (0.1 mol L-1) at pH 2.0, employing square-wave adsorptive stripping voltammetry. The electrochemical behavior of 2C-B on SPE-Gr/CTS exhibited one irreversible oxidation and a reversible redox process. The proposed method presented a dynamic linear range for 2C-B determination (0.05 to 7.5 μmol L-1) with a low LOD (0.015 μmol L-1). Moreover, the stability of 2C-B electrochemical responses on SPE-Gr/CTS was confirmed using the same or different electrodes (N = 3), with a relative standard deviation of less than 5.0%. Interference studies with seventeen other illicit drugs and adulterants demonstrated that the proposed method is selective for 2C-B detection even in the presence of these substances. Real seized and oral fluid samples containing 2C-B were analyzed using this method, and the results were confirmed by LC-MS. The proposed device demonstrates to be an environmentally friendly and selective sensor for 2C-B detection in forensic analysis, offering a rapid and straightforward screening method for seized and biological samples. In addition, a portable and sensitive determination of 2C-B in forensic samples is presented with minimal sample consumption (50 μL).

The motivational impact of sport education model on daily physical activity levels among university students: a mediation analysis.

This study investigates the effects of the sport education model on physical literacy and its subsequent impact on daily physical activity levels among university students. Through mediation analysis, this study seeks to uncover the role of situational motivation in these effects. The participants in this study consist of 188 university students (male n = 132, female n = 70; mean age: 18.53 years) who were exposed to an 8-class, 10-lesson season as part of their physical education curriculum. Self-report measures were collected at baseline (1st lesson), post-intervention (10th lesson), and follow-up phases (5 weeks after). The results reveal significant mediation effects at the post-intervention (β = 0.201, t = 3.576, p < .001) and follow-up (β = 0.187, t = 3.069, p < .01) phases. Additionally, significant direct effects of physical literacy on physical activity metabolic minutes were found in the post-intervention phase (β = 0.293, t = 1.807, p < .05). Gender differences were also observed in the multigroup analysis. These findings demonstrated the motivation mediates the impact of the sport education model on promoting physical activity and highlight the multidimensional nature of physical literacy. Future research is recommended to explore the application of this pedagogical model in different educational contexts and populations, utilising robust analytical methods.

Widely Integrated Services in Home (WISH) for homebound older adults: a study protocol for a randomized encouragement trial.

Home-based primary care (HBPC) is an emerging patient-centered, interprofessional healthcare service model that can address unmet medical needs and care burdens for homebound older adults. In December 2022, the Ministry of Health and Welfare in South Korea launched the Home-Based Medical Center Demonstration project to provide a new bundle payment for physician home visits. In this study, we seek to determine whether the recently introduced HBPC services in South Korea have been associated with a reduction in long-term care (LTC) facility admissions and acute hospitalizations among homebound older adults. The study is a community-based, multicenter, two-arm, randomized encouragement design trial with a 12-month follow-up period (n = 600). Eligible study participants are community-dwelling LTC recipients with multimorbidity and functional deterioration. Study participants are recruited from five HBPC centers located in urban areas (Northeast Seoul, West Seoul, Daejeon, Wonju, and Paju). The study participants are randomly assigned to either the HBPC group or the usual care group with a 1:1 allocation ratio. Those assigned to the HBPC group receive longitudinal home visits at least once a month by an interprofessional HBPC team according to the Widely Integrated Services in Home (WISH) intervention protocol. This protocol adheres to the Integrated Care for Older People principles, which call for a person-centered assessment and broader integration of health and LTC services at the micro-, meso- and macro-levels. Primary outcomes of the trial are 1) between-group community survival days and 2) between-group potentially avoidable hospitalizations. Results of the treatment are estimated by both modified intention-to-treat and complier average causal effect analytic methods. This study aims to investigate the real-world effectiveness of HBPC on the reduction of LTC facility admissions and acute care hospitalizations in the community setting. The findings may inform healthcare policy decisions to expand HBPC services in South Korea and other countries. CRIS KCT0007921.

Mycotoxin Challenge in Dairy Cows: Assessment of the Efficacy of an Anti-Mycotoxin Agent by Adopting an In Vitro Rumen Simulation Method

To protect ruminants from the harmful effects of mycotoxins, anti-mycotoxin agents can be added to the dietary ration, thus guaranteeing animal health and production. Therefore, the objective of this study was to evaluate the in vitro ruminal initial sequestration (weak binding) and subsequent desorption (strong binding) of an anti-mycotoxin agent based on a mixture of adsorbing material, turmeric and milk thistle extracts and yeast-based components to adsorb or bio-convert aflatoxins (AF), fumonisins B1 and B2 (FB), trichothecene deoxynivalenol (DON), T-2 and HT-2 toxins, and zearalenone (ZEN). Two doses were tested: Dose 1 simulated 30 mg/cow/d, while Dose 2 simulated 90 mg/cow/d of the anti-mycotoxin agent. Each treatment involved three analytical replicates at each of three incubation times (1, 4, and 24 h post-incubation), with two independent experimental runs providing experimental replicates. Analytical methods, including UHPLC-HRMS and multivariate analyses, were used to both quantify mycotoxin concentrations and reveal dose-dependent reductions, with statistical validations indicating significant changes in mycotoxin levels across both dose and time. The results indicated that the anti-mycotoxin agent was able to highly bind AFB1, T2, and HT-2 toxins since its concentration was always under the limit of detection (&lt;1 ppb). Regarding ZEN (weak binding mean: 94.6%; strong binding mean: 62.4%) and FBs (weak binding mean: 58.7%; strong binding mean: 32.3%), orthogonal contrasts indicated that the anti-mycotoxin agent was able to effectively bind these toxins using Dose 1 (p &lt; 0.05). This finding suggests that Dose 1 may be sufficient to achieve the targeted effect and that a further increase does not significantly improve the outcome. Regarding DON, a strong linear relationship was observed between dose and adsorption. However, the complex interactions between the mycotoxin, the ruminal environment, and the anti-mycotoxin agent made it difficult to establish a clear dose–effect relationship (p &gt; 0.10). UHPLC-HRMS analysis identified over 1500 mass features in rumen samples, which were further analyzed to assess the effects of the anti-mycotoxin agent. Hierarchical clustering analysis (HCA) revealed significant changes in the untargeted metabolomic profiles of samples treated with mycotoxins compared to control samples, particularly after 24 h with the anti-mycotoxin treatments. Clear differences were noted between strong binding and weak binding samples. Further analysis using orthogonal partial least squares discriminant analysis (OPLS-DA) highlighted distinct metabolomic profiles, with stronger predictive ability in the strong binding group (Q2 cumulative value of 0.57) compared to the weak binding group (0.30). The analysis identified 44 discriminant compounds in the strong binding model and 16 in the weak binding model. Seven compounds were common to both groups, while silibinin, known for its antioxidant and anti-inflammatory properties, was found among the unique compounds in the weak binding group. Overall, the findings suggest that both doses of the anti-mycotoxin agent significantly influenced the chemical profiles in the rumen, particularly enhancing the binding of mycotoxins, thereby supporting the role of phytogenic extracts in mitigating mycotoxin effects.

Fishing Vessel Risk and Safety Analysis: A Bibliometric Analysis, Clusters Review and Future Research Directions

This study conducts a bibliometric analysis to evaluate the current research landscape and identify future directions in fishing vessel safety. Using the Scopus database, 285 relevant documents were collected and analyzed using the Biblioshiny app version 4.1 in the bibliometrix R package and VOSviewer version 1.6.20. The analysis generated an authors’ collaboration network, a three-field plot, and a keyword Thematic map, which were used for citation analysis, while VOSviewer was utilized to build networks between journals, articles, affiliations, countries, and keywords, enabling bibliographic coupling. The results identified four primary research clusters: Accident/Risk Analysis, Human Errors, Stability, and Operation. A detailed review of selected studies within these clusters was conducted, focusing on accident and risk factors, analytical methods, their strengths and weaknesses, and potential improvements. Based on these findings, a discussion was provided on future research directions in fishing vessel safety. The results suggest that future research should prioritize the integration of advanced technologies, enhancement of real-time monitoring capabilities, and promotion of international collaboration to ensure the safety of fishermen in hazardous environments.

Antiseptic Surface Based on Antibacterial Polyethylene Composites with Silver Fillers: Stability in Aqueous Solution

One method to reduce the spread of pathogens is to use clean surfaces. These have long-acting components, and their use would reduce the massive consumption of disinfectants and cleaning products. In order to ensure the safety of these surfaces in water-based systems and prevent mishandling and potential health and environmental risks, this study analyzed the stability of clean surfaces made of polyethylene with three silver compounds with different water solubility. The surfaces were subjected to erosion at 40 °C by immersing them in aqueous solutions of 3% acetic acid (w/v), 50% ethanol (v/v), and deionized water. The ionic silver release was monitored in real-time in situ via voltammetry using an Ag/S2− electrode. Analytical methods such as Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) were employed to elucidate the surface alteration. The plastic residue after immersion varied depending on the pH and the type of solvent used, with a higher plastic migration observed when in contact with the water-ethanol mixture. Furthermore, a correlation was identified between surface stability, oxygen composition in the antibacterial, and water solubility, influencing increased surface oxidation.

Asymptotic and Oscillatory Analysis of Second-Order Differential Equations with Distributed Deviating Arguments

This paper focuses on studying the oscillatory properties of a distinctive class of second-order advanced differential equations with distributed deviating arguments in a noncanonical case. Utilizing the Riccati method and the comparison method with first-order equations, in addition to other analytical methods, we have established criteria to test whether the solutions of the studied equation exhibit oscillatory behavior. To verify the validity of the results we obtained and determine their applicability, we present some examples to confirm the strength and accuracy of our proposed criteria.

Effects of conical singularity and Wu-Yang magnetic monopole on thermodynamic properties of harmonic oscillator interacting with potential

Abstract This paper investigates the thermodynamic properties of the harmonic oscillator system in a conical singularities background. Moreover, we incorporate a Wu-Yang magnetic monopole (WYMM) and inverse square potential into the quantum system and analyze the resulting effects. Using analytical methods, we derive the energy eigenvalues and study the thermodynamic properties, such as the partition function, Helmholtz free energy, Gibbs's free energy and specific heat capacity at finite temperature $T \neq 0$. Our findings demonstrate that these physical parameters are influenced by the topological parameter, strength of WYMM and potential parameters. These results provide valuable insights into the interplay between thermodynamic properties of a quantum mechanical problem and the gravitational effects.

The reflection of a planar impulsive shock wave at a liquid–gas interface

The reflection of a shock pulse at a liquid–gas interface occurs in many applications, from lithotripsy to underwater explosions and additive manufacturing. In linear theory, reflection and transmission at an interface depend only on the impedance difference, but this does not hold for a nonlinear pulse. This work develops an analytical framework for computing the reflection and transmission coefficients for an impulsive shock wave at a liquid–gas interface. The problem is treated analytically by considering idealised pulses and solving a series of consecutive Riemann problems. These correspond to the initial interaction with the interface and important subsequent wave interactions that enable a complete description of the process to be obtained. Comparisons with numerical and existing analytical approaches are made for the case of a water–air interface. In the acoustic limit, the method produces results identical to those of linear acoustic theory. As the pulse strength increases, the proposed method agrees well with numerical simulation results, whereas existing analytical methods that consider only the interface fail. We detail how a reflecting pulse can put water into tension without any incident negative pressure. It is further shown that the magnitude of the reflection coefficient decreases with increasing incident shock pressure, and the reflected pulse widens. Reflections of pulses with positive and negative pressures temporarily create negative pressure regions with greater magnitude than the incident pulse. Finally, we consider non-idealised waves. Comparisons with simulations show that the reflection characteristics can be explained qualitatively using the analytical method, and the reflection coefficients are predicted accurately.

From Lithuanian Riflemen to Forest Brothers: Research on the Development of the Local Military Structure

The article analyses the Thorn Company, a partisan unit that operated in northeast Lithuania, and the link of its partisans with the previously established societal tradition of self-defence and armed activity. The author seeks to reveal the extent to which the partisans belonged to the pre-war Lithuanian Riflemen’s Union and protective squads of small towns and villages which were formed during the uprising of 1941 as well as their participation in the divisions of public and auxiliary police which operated in 1941–1944. The research was carried out using analytical, inductive and statistical methods. The tradition of armed resistance and self-defence had been maturing in the territory of the future area of activity of Thorn Company (Zarasai regional district, Salakas village area). This tradition had been developing ever since the fights for independence in the early part of the twentieth century. Even then the local population who formed a squad of saboteurs actively assisted the Lithuanian army. The mindset of armed resistance to invaders was shaped, their skills of armed fighting were improved, and a framework of self-defence was taking shape. The memory and traditions of freedom fighting were nourished and passed on to the younger generation throughout the two decades of Lithuanian independence in the riflemen’s squadrons, which operated in the Salakas village district. This tradition determined an active role for riflemen from Salakas area in the anti-Soviet June uprising of 1941, and in their participation in policing units during the period of Nazi occupation (the latter activity was determined by anti-Soviet rather than pro-Nazi convictions). The military activity tradition shaped in the context of the above mentioned events was also alive in the postwar period. Throughout the whole period of the military company’s existence, its backbone was made up of fighters who gained fighting experience in riflemen’s squadrons during the independence period as well as in the Naziperiod police and self-defense divisions. Many ff them served in earlier military formations of earlier periods, and thus presumably cherished a certain collective mindset, made up of patriotism, belief in the possibility of restoring Lithuanian sovereignty and a deep anti-Soviet disposition. They must have been inclined to think that the gun was a reliable means of survival, and armed fighting was the most suited form of relating to the occupiers.