bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel ELAC2 Mutations in Individuals Presenting with Variably Severe Neurological Disease in the Presence or Absence of Cardiomyopathy
Authors: Cafournet Cérane , Zanin Sofia , Guimier Anne , Hully Marie , Assouline Zahra , Barcia Giulia , de Lonlay Pascale , Steffann Julie , Munnich Arnold , Bonnefont Jean-Paul , Rötig Agnès , Ruzzenente Benedetta , Metodiev Metodi D.
Published: February 2023

Transcription of mitochondrial DNA generates long polycistronic precursors whose nucleolytic cleavage yields the individual mtDNA-encoded transcripts. In most cases, this cleavage occurs at the 5′- and 3′-ends of tRNA sequences by the concerted action of RNAseP and RNaseZ/ELAC2 endonucleases, respectively. Variants in the ELAC2 gene have been predominantly linked to severe to mild cardiomyopathy that, in its milder forms, is accompanied by variably severe neurological presentations. Here, we report five patients from three unrelated families. Four of the patients presented mild to moderate cardiomyopathy and one died at 1 year of age, one patient had no evidence of cardiomyopathy. The patients had variable neurological presentations that included intellectual disability, ataxia, refractory epilepsy, neuropathy and deafness. All patients carried previously unreported missense and nonsense variants. Enzymatic analyses showed multiple OXPHOS deficiencies in biopsies from two patients, whereas immunoblot analyses revealed a decreased abundance of ELAC2 in fibroblasts from three patients. Northern blot analysis revealed an accumulation of unprocessed mt-tRNAVal-precursor consistent with the role of ELAC2 in transcript processing. Our study expands the genetic spectrum of ELAC2-linked disease and suggests that cardiomyopathy is not an invariably present clinical hallmark of this pathology.
Chitosan or Cyclodextrin Grafted with Oleic Acid Self-Assemble into Stabilized Polymeric Micelles with Potential of Drug Carriers
Authors: Zlotnikov Igor D. , Streltsov Dmitriy A. , Belogurova Natalya G. , Kudryashova Elena V.
Published: February 2023

Polymeric micelles combining the advantages of biocompatible poly- and oligosaccharides with classical micellar amphiphilic systems represent a promising class of drug carriers. In this work, micelles based on chitosan (or cyclodextrin) and oleic acid with various modification degrees were synthesized—the most optimal grafting degree is 15–30% in terms of CMC. According to NTA data, micelles have a hydrodynamic diameter of the main fraction of 60–100 nm. The inclusion of the antibacterial agents: moxifloxacin or rifampicin in micelles was studied by FTIR spectroscopy and fluorescence spectroscopy using a pyrene label (using monomer-excimer approach). When aromatic molecules are incorporated into micelles, the absorption bands of C-H bonds of the fatty tails of micelles shift towards smaller wavenumbers, indicating a stabilization of the micelles structure, and the microenvironment of the drug molecule changes according to the low frequencies shift and intensity changes in oscillation frequencies of 1450 cm−1 corresponding to aromatic fragment. Loading of moxifloxacin and rifampicin into micelles leads to a change in the fluorescent properties: a shift of the maximum of fluorescence emission to the long-wavelength region and an increase in the fluorescence anisotropy due to a drastic increase in the hydrodynamic volume of the fluorophore-containing rotating fragment. Using the pyrene label, the critical micelle concentrations were determined: from 4 to 30 nM depending on the polymer composition. Micellar systems enhance the effect of the antibiotic by increasing the penetration into bacterial cells and storing the drug in a protective coat. As a part of the supramolecular structure, the antibiotic remains active for more than four days, while in free form, the activity decreases after two days. In pharmacokinetic experiments, in vivo moxifloxacin in micellar systems show 1.7 times more efficiency compared to free form; moreover, two times higher maximal concentration in the blood is achieved. The advantage of polymer micellar systems in comparison with simple cyclodextrins and chitosan, which do not so significantly contribute to the antibacterial and pharmacokinetic parameters, was shown. Thus, polymeric micelles are one of the key approaches to improving the effectiveness of antibacterial drugs and solving the problems of resistant bacterial infections and multidrug resistance.
First Use of Non-Invasive Spinal Cord Stimulation in Motor Rehabilitation of Children with Spinal Muscular Atrophy
Authors: Novikov Anton , Maldova Maria , Shandybina Natalia , Shalmiev Ivan , Shoshina Elena , Epoyan Natalia , Moshonkina Tatiana
Published: February 2023

Spinal muscular atrophy (SMA) is characterized by the degeneration of spinal alpha motorneurons. Nusinersen demonstrated good efficacy in the early disease phases. The feasibility of transcutaneous spinal cord stimulation (tSCS) in motor rehabilitation of patients with spinal cord injury has been demonstrated. We hypothesize that tSCS may activate intact and restored by nusinersen motorneurons and slow down the decline in motor activity, and may contribute to the development of motor skills in children with SMA. A case series is presented. Five children (6–13 years old) with SMA type II or III participated in the study. They were treated with nusinersen for ~2 years. Application of tSCS was carried out during physical therapy for 30–40 min per day in the course of 10–14 days. Outcome measures were goniometry of joints with contracture, forced vital capacity (FVC), RULM and HFMSE scales. The participants tolerated the stimulation well. The reduction of the contracture was ≥5 deg. RULM and HFMSE increased by ~1–2 points. Predicted FVC increased by 1–7% in three participants. Each participant expanded their range of active movements and/or learned new motor skills. Spinal cord stimulation may be an effective rehabilitation method in patients treated with nusinersen. More research is needed.
Potential of Alpha-(α)-Solanine as a Natural Inhibitor of Fungus Causing Leaf Spot Disease in Strawberry
Authors: Xu Ning , Lu Huan , Yi Xueqian , Peng Simin , Huang Xiaohui , Zhang Yu , He Changzheng
Published: February 2023

Curvularia trifolii is an important pathogenic fungus that causes leaf spot disease in strawberry and other crops. Increased resistance in pathogenic fungi against chemical fungicides necessitates the search for biological alternatives to control plant fungal diseases. The present study aimed to perform transcriptome and metabolome analysis of C. trifolii fungi. We evaluated the potential of an alkaloid, namely alpha (α)-solanine, to inhibit the growth of Curvularia under in vitro conditions. Furthermore, transcriptomic and metabolomic analysis of treated C. trifolii was performed to identify the differential genes and metabolites. Results revealed that treatment with α-solanine resulted in the poor growth and development of fungal spores. The transcriptome analysis revealed that 1413 genes were differentially expressed (DEGs), among which 340 unigenes were up-regulated, 100 unigenes were down-regulated, and the rest were unaffected in treated samples. Gene ontology analysis revealed that the majority of the genes were related to oxidative stress in the fungus. Additionally, using ultra-high performance liquid chromatography-tandem mass spectrometry, we identified 455 metabolites, among which the majority of metabolites were related to lipid biosynthesis. The high number of genes related to lipid biosynthesis and reactive oxygen species revealed that α-solanine causes oxidative stress in Curvularia, leading to growth inhibition, and can be potentially used as an alternative to chemical fungicides.
Prevalence of Malnutrition among Syrian Refugee Children from Lebanon
Authors: Mroue Tamara , Heras Betlem , Soriano Jose M. , Morales-Suarez-Varela María
Published: February 2023

Today, the situation of Syrian refugees is one of the world’s worst humanitarian crises. To estimate the prevalence of malnutrition among pediatric populations of Syrian refugees, 176 Syrian refugee children, with stays of more than two years at three refugee camps (Zalhé, Deddeh, and Kfar Jouz) or from the town of Yohmor, Lebanon were authorized by their parents to participate in this study. The children were anthropometrically evaluated and height-for-age Z-score (HAZ), weight-for-age Z-score (WAZ), and weight-for-height (WHZ) Z-scores were obtained and compared with WHO standards. Furthermore, mid-upper arm circumference (MUAC) was analyzed for screening children 6–59 months old. According to the anthropometric measures, no child met the criteria for chronic, global, acute malnutrition (CGAM), severe acute malnutrition (SAM), or moderate acute malnutrition (MAM). In the total sample, 49.4% of participants were moderately thin, with girls presenting a higher prevalence of thinness than that of boys. Thus, the absence of high rates of malnutrition was verified despite the magnitude of the Syrian refugee’s problem. The data provided by this study identify the need to carry out further research to assess anthropometric growth and nutritional status among long-staying refugee children in order to prevent any health issues that may arise in the future.
Serum OPG and RANKL Levels as Risk Factors for the Development of Cardiovascular Calcifications in End-Stage Renal Disease Patients in Hemodialysis
Authors: Spartalis Michalis , Kasimatis Efstratios , Liakou Eleni , Sampani Erasmia , Lioulios Georgios , Christodoulou Michalis , Stai Stamatia , Moysidou Eleni , Efstratiadis George , Papagianni Aikaterini
Published: February 2023

Cardiovascular calcifications (CVC) are frequently observed in chronic kidney disease (CKD) patients and contribute to their cardiovascular mortality. The aim of the present study was to investigate the impact of osteoprotegerin (OPG)/Receptor Activator of NF-κΒ (RANK)/RANK ligand (RANKL) pathway in the development and evolution of CVCs in hemodialysis patients. In total, 80 hemodialysis patients were assessed for the presence of vascular (abdominal aorta and muscular arteries) calcifications and results were correlated to serum OPG and RANKL levels and the OPG/RANKL ratio. Traditional cardiovascular risk factors and mineral bone disease parameters were also estimated. The presence of VCs was also evaluated 5 years after the initiation of the study, and results were correlated to the initial serum OPG levels. Age, diabetes mellitus, coronary artery disease and OPG levels (p < 0.001) were associated with VCs, whereas RANKL levels were not. Multivariate analysis though revealed that only OPG levels were significantly associated with abdominal aorta calcifications (p = 0.026), but they were not correlated with the progression of VCs. Serum OPG levels are positively and independently associated with VCs in HD patients, but not with their progression. RANKL levels did not show any associations, whereas further studies are needed to establish the significance of OPG/RANKL ratio.
Effects of Microencapsulated Essential Oils on Equine Health: Nutrition, Metabolism and Methane Emission
Authors: Elghandour Mona M. M. Y. , Maggiolino Aristide , García Erendira Itzel Ceja , Sánchez-Aparicio Pedro , De Palo Pasquale , Ponce-Covarrubias José Luis , Pliego Alberto Barbabosa , Salem Abdelfattah Z. M.
Published: February 2023

This review examines the available data regarding the positive effects of microencapsulated essential oils (EOs) on the nutrition, metabolism, and possibly the methane emission of horses. A literature review was conducted on the effect of microencapsulated (EOs) on the health of horses. The information comprises articles published in recent years in indexed journals. The results indicate that mixtures of microencapsulated EOs may be beneficial to equine health due to their antimicrobial and antioxidant activity, as well as their effects on enteric methane production, nutrient absorption, and immune system enhancement. Moreover, encapsulation stabilizes substances such as EOs in small doses, primarily by combining them with other ingredients.
Influence of Gutta-Percha Surface on Enterococcus faecalis Initial Adhesion In Vitro: An Atomic Force Microscopy Study
Authors: Ribeiro Allan Victor , Velásquez-Espedilla Evelyn Giuliana , de Barros Mirela Cesar , de Melo Simas Letícia Lobo , de Andrade Flaviana Bombarda
Published: February 2023

The aim of this study was to evaluate the influence of surface topography of gutta-percha (GP) cones and plasticized disks of GP on the initial adhesion of Enterococcus faecalis (E. faecalis). The GP cones (Tanari and Dentsply brands) were cut 3 mm from the apical portion and fixed on a glass slide. To make the disks, the cones were thermoplasticized in standardized molds. The specimens were divided into groups according to the shape of the GP and the presence or absence of the bacteria. For contamination, the strain of E. faecalis (ATCC 29212) was used. The surface topography was analyzed using an atomic force microscope (AFM). The surface, roughness, and waviness parameters were evaluated by the Kruskal–Wallis and Dunn test. The comparison between disks and cones showed significant differences, where the cones were rougher, with a higher value attributed to the Dentsply cone (DC group). The same was observed for the waviness. After contamination, there was greater bacterial accumulation in cones, especially in their valleys, but both the surface and the topography became more homogeneous and smoother, with no differences between disks and cones of both brands. The topographic surface of the GP, at the micro and nanoscale, influences the initial adhesion of E. faecalis, with a greater tendency for contamination in regions associated with the presence of roughness and waviness. In this context, plasticization of GP is indicated, as it reduces surface irregularities compared to cones, contributing to less retention of bacteria.
Investigation of the Impact of High Concentration LiTFSI Electrolytes on Silicon Anodes with Reactive Force Field Simulations
Authors: Cavers Heather , Steffen Julien , Gogoi Neeha , Adelung Rainer , Hartke Bernd , Hansen Sandra
Published: February 2023

The initial formation cycles are critical to the performance of a lithium-ion battery (LIB), particularly in the case of silicon anodes, where the high surface area and extreme volume expansion during cycling make silicon susceptible to detrimental side reactions with the electrolyte. The solid electrolyte interface (SEI) that is formed during these initial cycles serves to protect the surface of the anode from a continued reaction with the electrolyte, and its composition reflects the composition of the electrolyte. In this work, ReaxFF reactive force field simulations were used to investigate the interactions between ether-based electrolytes with high LiTFSI salt concentrations (up to 4 mol/L) and a silicon oxide surface. The simulation investigations were verified with galvanostatic testing and post-mortem X-ray photoelectron spectroscopy, revealing that highly concentrated electrolytes resulted in the faster formation and SEIs containing more inorganic and silicon species. This study emphasizes the importance of understanding the link between electrolyte composition and SEI formation. This ReaxFF approach demonstrates an accessible way to tune electrolyte compositions for optimized performance without costly, time-consuming experimentation.
Tuning the Parameters of Cu–WS2 Composite Production via Powder Metallurgy: Evaluation of the Effects on Tribological Properties
Authors: Freschi Marco , Dragoni Lara , Mariani Marco , Haiko Oskari , Kömi Jukka , Lecis Nora , Dotelli Giovanni
Published: February 2023

Metal matrix self-lubricating composites exhibit outstanding performance in various environments, reaching the required properties by modifying the reinforcement–matrix ratio and the production method. The present research investigated the effects on tribological performance and electrical properties of different pressure loads, maintaining pressing time, and sintering temperatures during the production of copper–10 wt% tungsten disulfide (Cu–WS2) composite via powder metallurgy. Moreover, additional thermo-mechanical treatments were evaluated, namely second pressing and second sintering steps. The density and the hardness of the produced composites were measured, as well as the electrical resistivity, considering sliding electrical contacts as possible employment. The outputs of the wear tests were considered together with the analysis of the wear track via scanning electron microscopy and confocal laser scanning microscopy to understand wear mechanisms. Different production routes were compared in terms of electrical resistivity, wear coefficient, and specific wear rate, calculated by the confocal laser scanning microscopy, and friction coefficient, measured during the wear test. The main results highlighted that the increase in sintering temperature was detrimental to the hardness and tribological properties; higher load and additional pressing step determined a general improvement in the tested properties.
Dynamic Launch Trajectory Planning of a Cable-Suspended Translational Parallel Robot Using Point-to-Point Motions
Authors: Lin Deng , Mottola Giovanni
Published: February 2023

In the last decade, cable-suspended parallel robots have attracted significant interest due to their large workspaces and high dynamic performances. However, a significant drawback is that cables must always be in tension to control the motion. Using launch motions to reach a target can enlarge the workspace of such robots. For a spatial translational cable robot suspended by six pairwise-parallel cables, an analytical method for planning point-to-point dynamic trajectories is proposed. Using a second-order Bézier curve trajectory, the mechanism starts from a static condition, passes through intermediate points, and finally launches an object towards a target. According to the kinematic constraint conditions on the position, the velocity and acceleration of the end-effector at a prescribed point, the parametric expressions for a dynamically-feasible trajectory can be determined. The feasibility of the trajectory is analyzed under the constraint that cable tensions must be positive at all times. By changing the position of the end point of the trajectory and the total motion time, the kinematic conditions on the position and velocity as well as the feasibility constraint can be satisfied. Finally, our point-to-point dynamic launch trajectories are verified by simulations and experiments.
Investigation of the Pressure Fluctuation of Piston Chambers with Variable Slot Geometry
Authors: Wang Dongyun , Chen Congcong , Dong Hongkang
Published: February 2023

High-pressure fluctuation and flow ripple may cause unexpected vibration and noise when the piston pump works under severe conditions, and eventually lead to hydraulic transmission failure. The geometry of the valve plate has a great influence on the pressure fluctuation of the piston chamber. In order to optimize the structure of the valve plate, a mathematical model considering the slot geometry and the flow leakage of the lubricating interfaces was established in this paper. The model was used to investigate the pressure of the piston chamber, and then the accuracy of the model was validated by comparing simulation and experimental results. Further simulation results show that the pressure fluctuation in the piston chamber can be effectively suppressed by optimizing the triangular slots parameter of the valve plate, and a good design of the slot geometry could reduce the undershoot and overshoot of the pressure in piston chamber at the starting moment.
Editorial for Special Issue “Advances in Computer-Aided Technology”
Authors: Pollák Martin , Kočiško Marek
Published: February 2023

The determination of this Special Issue topic, in the field of Advances in Computer-Aided Technology belonging to the section “Mechatronic and Intelligent Machines”, was well received by the community of scientists and researchers [...]
A Study on the Effectiveness of Partial Discharge Models for Various Electrical Machines’ Insulation Materials
Authors: Verginadis Dimosthenis , Iakovidis Tryfon , Karlis Athanasios , Danikas Michael , Antonino-Daviu Jose-Alfonso
Published: February 2023

A vital component of electrical machines (EMs), which plays the most significant role in their reliable and proper operation, is their insulation system. Synchronous generators (SGs) are the most commonly used EMs in energy production and industry. Epoxy resin and mica are the predominant insulation materials for the SGs’ windings because their characteristics and properties are suitable for extending the lifetime of the insulation. Partial discharges (PDs) are both a symptom of insulation degradation, as they cause serious problems for insulation, and a means to identify possible insulation faults with offline and/or online PD tests and measurements. A comparison of three different equivalent circuit models of PDs occurring in different insulation materials (epoxy resin, mica, and a combination of these two) is presented in this paper. Different applied voltages and/or various geometries of voids are the factors investigated through simulations. The number of PDs, PD activity, and flashover voltages are examined in order to evaluate which of the aforementioned materials has the best reaction against PD activity.
A Brief Review of Computational Product Design: A Brand Identity Approach
Authors: Manavis Athanasios , Kakoulis Konstantinos , Kyratsis Panagiotis
Published: February 2023

On the way to designing customized products as one of the core activities of Industry 4.0, the strategy of computational design emerges as a unique design process due to its flexibility and simplicity. More specifically, the aforementioned strategy is concerned with the study of brand identity and its description in the development of commercial industrial products. The proposed design approach is focused on the study of branded product forms following computational design methodologies, i.e., employing textual or/and visual programming languages. The paper presents an overview of in-depth research studies which deal with the systematic way of creation, evolution, and transformation of industrial products with modern digital tools. Through the review, 100 studies have been analyzed over the last 15 years. The background of this research includes definitions from the specific four pillars of the modern theory of industrial design, e.g., product design, digital design, visual representation, and product identity. Furthermore, the current paper combines the use of computational design with specific parameters of visual brand elements in order to develop a methodological tool for the mass customization of industrial products. Moreover, the proposed framework offers a great deal of flexibility in both design and manufacturing, while many design alternatives could become available in a very short time. Finally, the impact of this paper is the correlation between computational design techniques and the theoretical background of brand identity principles (i.e., shapes, geometries, styles, textures, colors, and materials) for inspiring novel ideas among engineers, designers, and marketers.
Open-Loop Simulation of Active Vibration Control of Electrically Controlled Rotor
Authors: Li Kewei , Su Taoyong , Ma Jinchao , Zhang Zhaozhong
Published: February 2023

An electrically controlled rotor (ECR), also known as a swashplateless rotor, is an active rotor system that reduces the vibration load of the rotor through active control while achieving primary control by using a trailing edge flap system instead of a swashplate. In this study, the control effect of a 2Ω higher-order harmonic input on the vibration load of an ECR is investigated. First, an analytical aeroelastic model of the ECR is established based on Hamilton’s principle and an unsteady aerodynamic model with a flapped airfoil. On this basis, the use of higher-order harmonic flap control to reduce the vibration load of the ECR is investigated. The effect of the 2Ω higher-order harmonic flap control on the 2Ω vibration load of the example ECR is analyzed by sweeping the amplitude and phase of the higher-order harmonic flap control. The effect of higher-order harmonic flap control on the primary control of the ECR is also analyzed. The results show that the 2Ω higher-order flap deflection has the most significant control effect on the 2Ω vertical vibration load of the hub, that there is coupling between the higher-order flap deflection and the primary control of the ECR, and that the higher-order flap deflection disrupts the original equilibrium of the ECR.
Zero-Field Splitting in Cyclic Molecular Magnet {Cr8Y8}: A High-Frequency ESR Study
Authors: Fu Zhendong , Ouyang Zhong-Wen , Luo Qian-Cheng , Zheng Yan-Zhen , Tong Wei , Bu Huanpeng , Guo Hanjie , Zhao Jin-Kui
Published: February 2023

Cyclic 3d-4f molecular magnets have received considerable attention owing to their potential applications in high-density data storage and quantum information processing. As a rare example of ferromagnetic polynuclear Cr rings, {Cr8Y8} represents a valuable test bed to directly study the magnetic interaction between Cr3+ ions in large hexadecametallic {Cr8Ln8} (Ln = 4f metal) molecules. We have proposed a “single-J” model to approximate the low-temperature spin dynamics of {Cr8Y8} in our earlier study, while a zero-field splitting (ZFS) of the quantum levels was also suggested by the heat capacity data. In order to have a deeper understanding of the magnetism of {Cr8Y8}, it is necessary to verify the ZFS by means of high-resolution spectral methods and identify its origin. In this work, we present a high-frequency electron spin resonance (HF-ESR) study on the ZFS of {Cr8Y8}. The X-band ESR spectra consists of multi-peak structure, indicative of magnetic anisotropy that breaks the degeneracy between spin states in the absence of a magnetic field. HF-ESR spectra are collected to extract the ZFS parameters. We observed a sharp resonance peak due to the transitions between the S = 11 quantum levels and a broadband corresponding to a distribution of resonance peaks due to the ZFS of the S = 12 quantum levels. By analyzing HF-ESR spectra, we confirm the expected S = 12 ground state and determine its ZFS parameter D as −0.069 K, and, furthermore, we reproduce the spectra recorded at 154 GHz. The macrospin model proves to still be valid. The ZFS is attributed to the axial magnetic anisotropy, as found in some other Cr-based molecular wheels. The detailed HF-ESR investigation presented in this paper will benefit the studies on other {Cr8Ln8} wheels with magnetic Ln3+ ions and highlights the importance of the HF-ESR method as a high-resolution probe in determining the ZFS parameters with very small magnitude.
Preface to the Special Issue on “Computational Mechanics in Engineering Mathematics”
Authors: Booty Michael R.
Published: February 2023

Increases in computational resources and the constant development of numerical methods have greatly expanded the range and complexity of systems that can be simulated numerically [...]
Semi-Supervised Multi-Label Dimensionality Reduction Learning by Instance and Label Correlations
Authors: Li Runxin , Du Jiaxing , Ding Jiaman , Jia Lianyin , Chen Yinong , Shang Zhenhong
Published: February 2023

The label learning mechanism is challenging to integrate into the training model of the multi-label feature space dimensionality reduction problem, making the current multi-label dimensionality reduction methods primarily supervision modes. Many methods only focus attention on label correlations and ignore the instance interrelations between the original feature space and low dimensional space. Additionally, very few techniques consider how to constrain the projection matrix to identify specific and common features in the feature space. In this paper, we propose a new approach of semi-supervised multi-label dimensionality reduction learning by instance and label correlations (SMDR-IC, in short). Firstly, we reformulate MDDM which incorporates label correlations as a least-squares problem so that the label propagation mechanism can be effectively embedded into the model. Secondly, we investigate instance correlations using the k-nearest neighbor technique, and then present the l1-norm and l2,1-norm regularization terms to identify the specific and common features of the feature space. Experiments on the massive public multi-label data sets show that SMDR-IC has better performance than other related multi-label dimensionality reduction methods.
Student Engagement with Technology-Enhanced Resources in Mathematics in Higher Education: A Review
Authors: Ní Shé Caitríona , Ní Fhloinn Eabhnat , Mac an Bhaird Ciarán
Published: February 2023

The effectiveness of technology-enhanced resources in mathematics in higher education is far from clear, nor is student engagement with such resources. In this review article, we investigate the existing literature in three interrelated areas: student engagement with technology in higher education and mathematics; what works and what does not in technology in education and in mathematics in higher education; evaluating the use of technology in higher education and mathematics; and the use of frameworks and models. Over 300 research articles were identified for this purpose and the results are reported in this review. We found a dearth of studies in undergraduate mathematics education that specifically focus on student engagement with technology. In addition, there is no overarching framework that describes both the pedagogical aspects and the educational context of technology integration in mathematics.
Asymptotic ω-Primality of Finitely Generated Cancelative Commutative Monoids
Authors: García-García Juan Ignacio , Marín-Aragón Daniel , Vigneron-Tenorio Alberto
Published: February 2023

The computation of ω-primality has been object of study, mainly, for numerical semigroups due to its multiple applications to the Factorization Theory. However, its asymptotic version is less well known. In this work, we study the asymptotic ω-primality for finitely generated cancelative commutative monoids. By using discrete geometry tools and the Python programming language we present an algorithm to compute this parameter. Moreover, we improve the proof of a known result for numerical semigroups.
A Novel Approach to Decision-Making on Diagnosing Oncological Diseases Using Machine Learning Classifiers Based on Datasets Combining Known and/or New Generated Features of a Different Nature
Authors: Demidova Liliya
Published: February 2023

This paper deals with the problem of diagnosing oncological diseases based on blood protein markers. The goal of the study is to develop a novel approach in decision-making on diagnosing oncological diseases based on blood protein markers by generating datasets that include various combinations of features: both known features corresponding to blood protein markers and new features generated with the help of mathematical tools, particularly with the involvement of the non-linear dimensionality reduction algorithm UMAP, formulas for various entropies and fractal dimensions. These datasets were used to develop a group of multiclass kNN and SVM classifiers using oversampling algorithms to solve the problem of class imbalance in the dataset, which is typical for medical diagnostics problems. The results of the experimental studies confirmed the feasibility of using the UMAP algorithm and approximation entropy, as well as Katz and Higuchi fractal dimensions to generate new features based on blood protein markers. Various combinations of these features can be used to expand the set of features from the original dataset in order to improve the quality of the received classification solutions for diagnosing oncological diseases. The best kNN and SVM classifiers were developed based on the original dataset augmented respectively with a feature based on the approximation entropy and features based on the UMAP algorithm and the approximation entropy. At the same time, the average values of the metric MacroF1-score used to assess the quality of classifiers during cross-validation increased by 16.138% and 4.219%, respectively, compared to the average values of this metric in the case when the original dataset was used in the development of classifiers of the same name.
Application of Solar Activity Time Series in Machine Learning Predictive Modeling of Precipitation-Induced Floods
Authors: Malinović-Milićević Slavica , Radovanović Milan M. , Radenković Sonja D. , Vyklyuk Yaroslav , Milovanović Boško , Milanović Pešić Ana , Milenković Milan , Popović Vladimir , Petrović Marko , Sydor Petro , Gajić Mirjana
Published: February 2023

This research is devoted to the determination of hidden dependencies between the flow of particles that come from the Sun and precipitation-induced floods in the United Kingdom (UK). The analysis covers 20 flood events during the period from October 2001 to December 2019. The parameters of solar activity were used as model input data, while precipitations data in the period 10 days before and during each flood event were used as model output. The time lag of 0–9 days was taken into account in the research. Correlation analysis was conducted to determine the degree of randomness for the time series of input and output parameters. For establishing a potential causative link, machine learning classification predictive modeling was applied. Two approaches, the decision tree, and the random forest were used. We analyzed the accuracy of classification models forecast from 0 to 9 days in advance. It was found that the most important factors for flood forecasting are proton density with a time lag of 9, differential proton flux in the range of 310–580 keV, and ion temperature. Research in this paper has shown that the decision tree model is more accurate and adequate in predicting the appearance of precipitation-induced floods up to 9 days ahead with an accuracy of 91%. The results of this study confirmed that by increasing technical capabilities, using improved machine learning techniques and large data sets, it is possible to improve the understanding of the physical link between the solar wind and tropospheric weather and help improve severe weather forecasting.
The Specific Behavior of Economic Agents with Heterogeneous Expectations in the New Keynesian Model with Rigid Prices and Wages
Authors: Serkov Leonid , Krasnykh Sergey
Published: February 2023

The purpose and scientific novelty of this work is to analyze the changes and features of economic agents’ behavior when incorporating wage rigidity into a new Keynesian model under cognitive constraints of agents. The working hypothesis is the assumption that the forecasting of the output gap, inflation of prices and wages occurs with the help of fundamentalist and extrapolation rules. The first rule is based on forecasting the variables under study on the basis of their stationary values. The second rule is based on extrapolation of the latest available data on inflation and the output gap. The weight shares of agents applying these heuristic rules change endogenously, which is the source of endogenous waves of optimism and pessimism. An analysis of the impulse responses of interest rate and technology shocks suggests that a more flexible economy (an economy with flexible wages and rigid prices) is less prone to a spike in the economic cycle caused by waves of optimism and pessimism than a more rigid economy (an economy with rigid prices and wages) due to the inability of agents to respond immediately to exogenous disturbances in rigid conditions. Thus, these shocks cause wave effects in the economy, i.e., cyclical movements, i.e., a rigid economy will be more prone to booms and busts caused by alternating optimism and pessimism than a flexible economy. The model with an imperfect labor market is characterized by an increased concentration of vital forces at the values of 0 and 1, as well as in the mid-distribution compared to the base model. This feature provides a key explanation for the abnormal dynamics of the evolution of variables in this model. It is concluded that the difference between the degree of optimism and pessimism in the base model and in the model with rigid wages and prices is the full trust of agents in the central bank in targeting wage inflation in the absence of the stabilization of this inflation by the bank.
A Generalized Discrete Bohr–Jessen-Type Theorem for the Epstein Zeta-Function
Authors: Laurinčikas Antanas , Macaitienė Renata
Published: February 2023

Suppose that Q is a positive defined n×n matrix, and Q[x̲]=x̲TQx̲ with x̲∈Zn. The Epstein zeta-function ζ(s;Q), s=σ+it, is defined, for σ>n2, by the series ζ(s;Q)=∑x̲∈Zn∖{0̲}(Q[x̲])−s, and it has a meromorphic continuation to the whole complex plane. Let n⩾4 be even, while φ(t) is an increasing differentiable function with a continuous monotonic bounded derivative φ′(t) such that φ(2t)(φ′(t))−1≪t, and the sequence {aφ(k)} is uniformly distributed modulo 1. In the paper, it is obtained that 1N#N⩽k⩽2N:ζ(σ+iφ(k);Q)∈A, A∈B(C), for σ>n−12, converges weakly to an explicitly given probability measure on (C,B(C)) as N→∞.
A Cooperative Control Algorithm for Line and Predecessor Following Platoons Subject to Unreliable Distance Measurements
Authors: Escobar Carlos , Vargas Francisco J. , Peters Andrés A. , Carvajal Gonzalo
Published: February 2023

This paper uses a line-following approach to study the longitudinal and lateral problems in vehicle platooning. Under this setup, we assume that inter-vehicle distance sensing is unreliable and propose a cooperative control strategy to render the platoon less vulnerable to these sensing difficulties. The proposed control scheme uses the velocity of the predecessor vehicle, communicated through a Vehicle-to-Vehicle technology, to avoid significant oscillations in the local speed provoked by tracking using unreliable local distance measurements. We implement the proposed control algorithm in the RUPU platform, a low-cost experimental platform with wireless communication interfaces that enable the implementation of cooperative control schemes for mobile agent platooning. The experiments show the effectiveness of the proposed cooperative control scheme in maintaining a suitable performance even when subject to temporal distortions in local measurements, which, in the considered experimental setup, arise from losing the line-of-sight of the local sensors in paths with closed curves.
PCEP: Few-Shot Model-Based Source Camera Identification
Authors: Wang Bo , Yu Fei , Ma Yanyan , Zhao Haining , Hou Jiayao , Zheng Weiming
Published: February 2023

Source camera identification is an important branch in the field of digital forensics. Most existing works are based on the assumption that the number of training samples is sufficient. However, in practice, it is unrealistic to obtain a large amount of labeled samples. Therefore, in order to solve the problem of low accuracy for existing methods in a few-shot scenario, we propose a novel identification method called prototype construction with ensemble projection (PCEP). In this work, we extract a variety of features from few-shot datasets to obtain rich prior information. Then, we introduce semi-supervised learning to complete the construction of prototype sets. Subsequently, we use the prototype sets to retrain SVM classifiers, and take the posterior probability of each image sample belonging to each class as the final projection vector. Finally, we obtain classification results through ensemble learning voting. The PCEP method combines feature extraction, feature projection, classifier training and ensemble learning into a unified framework, which makes full use of image information of few-shot datasets. We conduct comprehensive experiments on multiple benchmark databases (i.e., Dresden, VISION and SOCRatES), and empirically show that our method achieves satisfactory performance and outperforms many recent methods in a few-shot scenario.
Algorithmic Aspects of Simulation of Magnetic Field Generation by Thermal Convection in a Plane Layer of Fluid
Authors: Tolmachev Daniil , Chertovskih Roman , Zheligovsky Vladislav
Published: February 2023

We present an algorithm for numerical solution of the equations of magnetohydrodynamics describing the convective dynamo in a plane horizontal layer rotating about an arbitrary axis under geophysically sound boundary conditions. While in many respects we pursue the general approach that was followed by other authors, our main focus is on the accuracy of simulations, especially in the small scales. We employ the Galerkin method. We use products of linear combinations (each involving two to five terms) of Chebyshev polynomials in the vertical Cartesian space variable and Fourier harmonics in the horizontal variables for space discretisation of the toroidal and poloidal potentials of the flow (satisfying the no-slip conditions on the horizontal boundaries) and magnetic field (for which the boundary conditions mimick the presence of a dielectric over the fluid layer and an electrically conducting bottom boundary), and of the deviation of temperature from the steady-state linear profile. For the chosen coefficients in the linear combinations, the products satisfy the respective boundary conditions and constitute non-orthogonal bases in the weighted Lebesgue space. Determining coefficients in the expansion of a given function in such a basis (for instance, for computing the time derivatives of these coefficients) requires solving linear systems of equations for band matrices. Several algorithms for determining the coefficients, which are exploiting algebraically precise relations, have been developed, and their efficiency and accuracy have been numerically investigated for exponentially decaying solutions (encountered when simulating convective regimes which are spatially resolved sufficiently well). For the boundary conditions satisfied by the toroidal component of the flow, our algorithm outperforms the shuttle method, but the latter proves superior when solving the problem for the conditions characterising the poloidal component. While the conditions for the magnetic field on the horizontal boundaries are quite specific, our algorithms for the no-slip boundary conditions are general-purpose and can be applied for treating other boundary-value problems in which the zero value must be admitted on the boundary.
Are State-Owned Enterprises Equally Reliable Information Suppliers? An Examination of the Impacts of State Ownership on Earnings Management Strategies of Chinese Enterprises
Authors: Lu Shan , Wu Peng , Gao Lei , Gifford Richard
Published: February 2023

Earnings management refers to a company’s use of either accounting techniques (accrual-based earnings management) or real economic activities (real earnings management) to manipulate reported earnings and mislead users of financial information. It often indicates serious ethical issues in a company’s management, which will affect the reliability and sustainability of a firm’s services in the supply chain. Using A-share listed Chinese firms on the Shanghai and Shenzhen Stock Exchanges, we investigated the impacts of state ownership on management’s decision to select real or accrual-based earnings management strategies. We found that state-owned enterprises (SOEs) tend to favor real earnings management over accrual-based earnings management more than non-SOEs. Furthermore, those SOEs that are controlled by the central government engage in real earnings management more often than those controlled by local governments. We also examined whether media attention and litigation interact with state ownership to affect earnings management. We found that SOEs, especially central SOEs, with a high level of media attention or an incidence of litigation, are more likely to use real earnings management. Our research can assist firms in making better decisions in selecting business partners and service suppliers in an emerging market through the assessment of management integrity.
Revisiting the Autocorrelation of Long Memory Time Series Models
Authors: Peiris Shelton , Hunt Richard
Published: February 2023

In this article we first revisit some earlier work on fractionally differenced white noise and correct some issues with previously published formulae. We then look at vector processes and derive formula for the Autocorrelation function, which is extended in this work to a larger range of parameter values than considered elsewhere, and compare this with previously published work.
On the Solution of Dynamic Stability Problem of Functionally Graded Viscoelastic Plates with Different Initial Conditions in Viscoelastic Media
Authors: Sofiyev Abdullah
Published: February 2023

The widespread use of structural elements consisting of functionally graded (FG) materials in advanced technologies has led to extensive research. Due to the difficulties encountered during modeling and problem solving, the number of studies on the dynamic behavior of structural elements made of FG viscoelastic materials is quite limited compared to the number examining FG elastic materials. This study is one of the first attempts to solve the dynamical problem by the mathematical modeling of functionally graded viscoelastic plates (FG-VE-Ps) and viscoelastic media together with different initial conditions. FG-VE-Ps on viscoelastic foundations (VE-Fs) are assumed to be under compressive edge load in the longitudinal direction. The governing equations for FG-VE-Ps on VE-Fs are derived using Boltzmann and Volterra concepts. The problem is reduced to the solution of integro-differential equation system using the Galerkin method. Then, by performing Laplace transforms, new analytical expressions for the time-dependent deflection function and critical time at different initial conditions are found. The loss of stability of FG-VE-Ps on VE-Fs is modeled to cover three time-varying ranges: the first is the range in which the deflection function decreases; the second is the transition interval; the third is the increase range of deflection function, which leads to the loss of stability. The time corresponding to the sharp increase of the deflection function is defined as the critical time, and is determined both theoretically and numerically. The results are compared with the results obtained by various methods to confirm their accuracy. Finally, the effects of VE-Fs, VE material properties, and FG profiles on the critical time behavior of plates are studied numerically.
Abdominal Lymphadenopathies: Lymphoma, Brucellosis or Tuberculosis? Multidisciplinary Approach—Case Report and Review of the Literature
Authors: Mirijello Antonio , Ritrovato Noemi , D’Agruma Angelo , de Matthaeis Angela , Pazienza Luca , Parente Paola , Cassano Dario Pio , Biancofiore Annalucia , Ambrosio Angelo , Carosi Illuminato , Serricchio Ettore , Graziano Paolo , Bazzocchi Francesca , Piscitelli Pamela , De Cosmo Salvatore
Published: February 2023

Abdominal pain represents a frequent symptom for referral to emergency departments and/or internal medicine outpatient setting. Similarly, fever, fatigue and weight loss are non-specific manifestations of disease. The present case describes the diagnostic process in a patient with abdominal pain and a palpable abdominal mass. Abdominal ultrasonography confirmed the presence of a mass in the mesogastrium. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans oriented toward calcific lymphadenopathies with increased metabolism in the positron emission tomography–computed tomography (PET-CT) scan. Laboratory examinations were inconclusive, although serology for Brucella and the Quantiferon test were positive. After multidisciplinary discussion, the patient underwent surgical excision of the abdominal mass. Histological examination excluded malignancies and oriented toward brucellosis in a patient with latent tuberculosis. The patient was treated with rifampin 600 mg qd and doxycycline 100 mg bid for 6 weeks with resolution of the symptoms. In addition, rifampin was continued for a total of 6 months in order to treat latent tuberculosis. This case underlines the need for a multidisciplinary approach in the diagnostic approach to abdominal lymphadenopathies.