bluuebunny/crossref_metadata_2025 huggingface dataset:
Hidden Dynamics, Multistability and Synchronization of a Memristive Hindmarsh–Rose Model
Authors: Qiao Shuai , Gao Chenghua
Published: January 2023

Reliable neuron models play an essential role in identifying the electrical activities, global bifurcation patterns, and dynamic mechanisms of neurons in electromagnetic environments. Considering that memristive autapse can characterize the self-induced effect of neurons, a five-dimensional Hindmarsh–Rose (HR) neuron model involving electric and magnetic fields is established. The detailed existence and stability analyses for equilibrium points are performed, and the complex time-varying stability, saddle-node bifurcation, and Hopf bifurcation behaviors are demonstrated. Interestingly, the bistable structures consisting of quiescent state and periodic bursting modes near the subcritical Hopf bifurcation and counterintuitive dynamic phenomena can be induced via appropriately adjusting the memristive current. Accordingly, the mechanism of positive feedback autaptic current decreases its firing frequency, while negative feedback autaptic current promotes its excitability and is revealed by the fast–slow dynamic analysis. Generally, the system possesses period-adding bifurcation patterns and comb-shaped chaotic structures as demonstrated by the numerical results. Importantly, it can be confirmed that the electrical activities and multistability of the system can be accurately predicted by analyzing the global dynamic behaviors of the Hamilton energy. Furthermore, it is verified that the unidirectional coupling controller involving energy is far more efficient and consumes lower energy than electrical synaptic coupling in achieving complete synchronization with mismatched parameters. These results provide potential guidance and help for further research in computational neuroscience and the design and control of intelligent sensors.
Transitivity and Shadowing Properties of Nonautonomous Discrete Dynamical Systems
Authors: Pi Jingmin , Lu Tianxiu , Xue Yanfu
Published: January 2023

This paper proves that some shadowing properties are sufficient conditions for being transitive or point-transitive for a nonautonomous discrete dynamical system. Moreover, considering weak mixing property and transitivity via Furstenberg family, this paper reveals the relationship for transitivity and mixing between [Formula: see text]-periodic systems and their induced autonomous discrete dynamical systems.
Hopf Bifurcation in a Reaction–Diffusion–Advection Population Model with Distributed Delay
Authors: Li Zhenzhen , Dai Binxiang , Han Renji
Published: January 2023

The existence, direction and stability of Hopf bifurcating periodic orbits near the positive spatially nonhomogeneous steady state of a reaction–diffusion–advection model with distributed delay and Dirichlet boundary condition are considered in this paper. By analyzing the characteristic equation and taking the bound of time delay as the bifurcation parameter, we show that Hopf bifurcation will occur when the shape parameter [Formula: see text], and the positive steady state is always stable when [Formula: see text]. The properties of Hopf bifurcations are then obtained by center manifold reduction and norm form methods. The effects of the distributed delay, shape parameter and advection on Hopf bifurcation values are also investigated. Finally, numerical simulations illustrate the effectiveness of the theoretical results.
Stability and Bifurcation Analysis of Bazykin’s Model with Holling I Functional Response and Allee Effect
Authors: Li Danyang , Liu Hua , Han Xiaotao , Lin Xiaofen , Wei Yumei
Published: January 2023

In this paper, we introduce Allee effect and predator competition in the Bazykin’s model with Holling I functional response. Theoretically, we analyze the existence and stability of equilibria, and derive the existence conditions of saddle-node bifurcation and Hopf bifurcation. In addition, in order to determine the stability of limit cycles, we explicitly calculate the first Lyapunov coefficient and prove that the positive equilibrium is not a center, but a weak focus with a multiplicity of at least two. Therefore, the system has Hopf bifurcation and Bautin bifurcation with two limit cycles. Our results indicate that the Allee effect and predator competition lead to a series of complex dynamic phenomena. Finally, numerical simulation verifies the effectiveness of the theoretical results.
Jerk Dynamics in the Minimal Universal Model of Laser
Authors: Ginoux Jean-Marc , Meucci Riccardo , Euzzor Stefano , Pugliese Eugenio , Sprott Julien Clinton
Published: January 2023

In a previous publication, we established a new paradigmatic model of laser with feedback including the minimal nonlinearity leading to chaos. In this paper, the jerk dynamics of this minimal universal model of laser is presented. It is proved that two equivalent forms of the model in jerk dynamics can be derived. The electronic circuit of the simpler dynamics is designed and implemented. The link between the minimal universal model of laser and the search for simple jerk circuits is established.
The 𝔤𝔩2-skein module of lens spaces via the torus and solid torus
Authors: Nguyen Hoang-An
Published: January 2023

We compute the action of the [Formula: see text]-skein algebra of the torus on the [Formula: see text]-skein module of the solid torus. As a result, we show that the [Formula: see text]-skein modules of lens spaces is spanned by [Formula: see text] elements.
An analytic model for gravitational collapse of spherical matter under mixed pressure
Authors: Yokoyama Shuichi
Published: January 2023

In this paper, we investigate spherically symmetric gravitational collapse of thick matter shell without radiation in the Einstein gravity with cosmological constant. The orbit of the infalling thick matter is determined by imposing an equation of state for the matter near interface, where pressure constituted of the transverse component and the longitudinal one is proportional to energy density. We present analytic solutions for the equation of state and discuss parameter region to satisfy physical conditions such as the absence of the shell crossing singularity, the monotonic increase of the emergent infinite redshift surface and energy conditions. We finally show that adopting the definition presented in arXiv:2005.13233 the total energy in this time-dependent system is invariant under the given time evolution.
Inhomogeneous equation of state and its consequences in a coupled fluid scenario and realization of Little Rip, Pseudo Rip and Bounce cosmology
Authors: Chakraborty Gargee , Chattopadhyay Surajit
Published: January 2023

Motivated by the work of P. H. Frampton et al. [Phys. Lett. B 708 (2012) 204; I. Brevik et al., Phys. Rev. D 84 (2011) 103508, arXiv:1107.4642 [hep-th]; I. Brevik et al., Phys. Rev. D 86 (2012) 063007, arXiv:1208.4770 [gr-qc]] this study reports on the reconstruction schemes for the inhomogeneous equation of state (EoS) first introduced by S. Nojiri et al., [Phys. Rev. D 72 (2005) 023003, arXiv:hep-th/0505215 [hep-th]] and the cosmology in the scenario of coupled fluid. We have considered the viscosity through the Eckart approach in an interacting system. The EoS parameter for the Little Rip, the [Formula: see text] in terms of cosmic time for Pseudo Rip, is reconstructed for the EoS for Bounce cosmology inhomogeneous viscous fluid. The EoS parameter is rebuilt for the coupled dark fluid in the nonviscous system for the Little Rip, Pseudo Rip and Bounce cosmology. The reconstructed EoS parameter for inhomogeneous viscous fluid was phantom for the Little Rip cosmology. The reconstructed EoS parameters of holographic Ricci dark energy (HRDE) of the coupled fluid in nonviscous systems are phantom for both the Little Rip and Pseudo Rip cosmology. The model HRDE of the coupled fluid in the nonviscous scenario for Pseudo-Rip cosmology indicates the possibility of singularity. The same model for the bounce cosmology violates the null energy condition and has the EoS parameter almost symmetric around the bouncing point.
WEAK ERROR RATES FOR OPTION PRICING UNDER LINEAR ROUGH VOLATILITY
Authors: BAYER CHRISTIAN , HALL ERIC JOSEPH , TEMPONE RAÚL
Published: January 2023

In quantitative finance, modeling the volatility structure of underlying assets is vital to pricing options. Rough stochastic volatility models, such as the rough Bergomi model [C. Bayer, P. K. Friz & J. Gatheral (2016) Pricing under rough volatility, Quantitative Finance 16 (6), 887–904, doi:10.1080/14697688.2015.1099717], seek to fit observed market data based on the observation that the log-realized variance behaves like a fractional Brownian motion with small Hurst parameter, [Formula: see text], over reasonable timescales. Both time series of asset prices and option-derived price data indicate that [Formula: see text] often takes values close to [Formula: see text] or less, i.e. rougher than Brownian motion. This change improves the fit to both option prices and time series of underlying asset prices while maintaining parsimoniousness. However, the non-Markovian nature of the driving fractional Brownian motion in rough volatility models poses severe challenges for theoretical and numerical analyses and for computational practice. While the explicit Euler method is known to converge to the solution of the rough Bergomi and similar models, its strong rate of convergence is only [Formula: see text]. We prove rate [Formula: see text] for the weak convergence of the Euler method for the rough Stein–Stein model, which treats the volatility as a linear function of the driving fractional Brownian motion, and, surprisingly, we prove rate one for the case of quadratic payoff functions. Indeed, the problem of weak convergence for rough volatility models is very subtle; we provide examples demonstrating the rate of convergence for payoff functions that are well approximated by second-order polynomials, as weighted by the law of the fractional Brownian motion, may be hard to distinguish from rate one empirically. Our proof uses Talay–Tubaro expansions and an affine Markovian representation of the underlying and is further supported by numerical experiments. These convergence results provide a first step toward deriving weak rates for the rough Bergomi model, which treats the volatility as a nonlinear function of the driving fractional Brownian motion.
The characterization of some cyclic groups by the product of element orders
Authors: Shafiei Hamed , Khosravi Behrooz , Baniasad Azad Morteza
Published: January 2023

Let [Formula: see text] be a finite group. We denote by [Formula: see text] the integer [Formula: see text] where [Formula: see text] denotes the order of [Formula: see text]. It is verified that some finite groups are uniquely determined by their orders and their product of element orders. In this paper, we prove that, if [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] are different prime numbers, then [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] are characterized by [Formula: see text] and if [Formula: see text], then [Formula: see text] or [Formula: see text].
ROLE OF PARTICLE SIZE, STIFFNESS, AND BLOOD FLOW VELOCITY ON MARGINATION OF NANOSCALE DRUG CARRIERS
Authors: WANG TONG , ZHANG SHUO , WEI YANHUI , XING ZHONGWEN
Published: January 2023

Targeted delivery of nanoscale drug carriers is becoming increasingly recognized as an important technology in the treatment of various diseases. The delivery efficiency depends on the ability of the particles drifting in blood flow toward the vascular endothelium and adhering to the specific sites. It is important to identify and understand the key factors that affect this margination process. In this study, the motion and margination of deformable drug carriers, e.g., liposomes in a cell-rich medium, have been investigated with an operator-splitting finite element method. Interactions between particles and fluid are implemented using an immersed boundary approach. We numerically evaluate the effect of particle and flow parameters, such as carrier size, carrier stiffness, and blood flow velocity, on the margination properties of drug carriers. Both the fluid–body interactions and cell–carrier interactions are fully considered. Overall, we observe a waterfall phenomenon which is crucial in the margination for the carriers to reach the cell-free layer (CFL) near the vascular endothelium. Simulation results show that smaller and stiffer carriers display higher tendency of margination and high flow velocity facilitates this process. This investigation provides insights of the margination mechanism, which offer valuable information in predicting the optimum parameters for the design of effective drug delivery systems.
OUT-OF-HOSPITAL CARDIAC ARREST COMPLICATED WITH ANTERIOR SPINAL ARTERY SYNDROME
Authors: ZHONG PENG , BI JIAQI , JIN TIENAN , CAO YANG , HAN FUJUN , ZHOU CHENLIANG , WANG ZHENZHOU
Published: January 2023

Background and objective: The success rate of thrombolytic therapy for patients with ultralong cardiac arrest caused by pulmonary embolism (PE) has been increasing. Thrombolytic timing to reduce the risk of bleeding is critical in preventing anterior spinal artery syndrome (ASAS). Methods: This is a case report of an out-of-hospital cardiac arrest (OHCA) caused by massive PE caused to a patient who received thrombolytic therapy after 140[Formula: see text]min of pre-hospital cardiopulmonary resuscitation (CPR). Results: A 51-year-old female was admitted to the emergency department due to an OHCA, presenting with no vital signs. After 140[Formula: see text]min of CPR, vital signs remained unstable, so thrombolytic therapy with 50-mg Alteplase was performed, spontaneously improving circulation. After admission to the ICU, the muscle strength of the lower limbs was 0 and both shallow and deep reflexes disappeared. After discharge, there was no improvement in the lower limbs at the six-month follow-up. A search of the PubMed database identified 13 cases of OHCA caused by PE who underwent in-hospital CPR before thrombolytic therapy for 2–150[Formula: see text]min, with an 8% incidence of ASAS and a 50% recovery rate. Conclusion: Ultralong CPR for patients with cardiac arrest caused by PE does not affect the outcome of thrombolytic therapy. However, it is necessary to identify these patients early and perform thrombolytic therapy to prevent the complications of CPR as well as the injury to the upper motor neurons caused by thrombosis.
NEUROMODULATION MODEL BASED ON MULTI-ELECTRODE COMBINED ELECTRICAL STIMULATION AND ANALYSIS OF SIGNAL CONDUCTION MECHANISM
Authors: HE LINGLI , HE WENJING , WANG YUFENG , WEI XIAOQIN , DU FANYU , ZHOU GUOMIN , ZHANG LU , ZHANG SHUANG
Published: January 2023

This study aimed to analyze the diffusion of electrical stimulation signals in human tissue and provide a theoretical basis for multi-electrode combined stimulation. The standard single-layer human head model based on electromagnetic simulation was taken as the geometric structure model. The model filler was assumed to be muscle tissue, and a finite element model with muscle characteristics was established. A 20-mA DC electrical signal was input, and the propagation mechanism of the signal in the simplified brain model was calculated and analyzed through multi-physical field simulation software. The signal was mainly concentrated around the electrode; when multi-electrode combined stimulation was used, signal superposition existed at the geometric center of the model, and the signal was enhanced. Slice interception analysis demonstrated that the signal attenuation intensity was approximately 8 dB/cm in homogeneous muscle tissue. To compare the performance of the single-layer model and multi-layer model, a semi-refined digital brain model was established, and simulated signal diffusion of the two models was analyzed. Comparative analysis found that due to the uneven distribution of tissues and the high shielding property of bone, the signal was highly scattered at the bone contact, but the superposition of signals in the brain center still existed.
COHERENCE NETWORKS OF BILATERAL UPPER LIMB MOTIONS IN CHRONIC STROKE PATIENTS
Authors: PAN BINGYU , LIU TIANSHU
Published: January 2023

Understanding the mechanisms of how the skeletal system reduces multiple degrees of freedom in motor control is very important in the field of neurorehabilitation. We therefore need to understand the functional connectivity of these synergistic patterns in bilateral upper limb of stroke patients from different Brunnstrom Stages. The intermuscular coherence at different frequency bands is decomposed to obtain muscle synchronization. Muscle networks were then applied to describe the functional connectivity between muscle pairs. We recruited 35 stroke patients with Brunnstrom Stages III-VI. Muscle activity was acquired from seven muscles around forearm while participants performed voluntary upward reaching with both affected and unaffected sides. We decomposed IMC spectra by negative matrix factorization to identify shared frequencies and co-modulated muscles. Two muscle networks were found and functional muscle networks are evaluated by strength, transitivity and global efficiency. Results showed that the network topology was different significantly between the two sides and between Brunnstrom stages of stroke patients. These findings can throw light on the understanding of motor control and rehabilitation of motor impairment for stroke survivors, which may promote the post-stroke rehabilitation process by detecting impaired neuromuscular coordination in frequency domain.
A NETWORK PHARMACOLOGICAL INVESTIGATION INTO THE TREATMENT OF PERIMENOPAUSAL DEPRESSION WITH A WARMING AND TONIFYING KIDNEY-YANG RECIPE
Authors: JIANG YUCHANG , GAN ZAILI , LI MI , SU YUE , JIANG YONG , PENG YANGZHI
Published: January 2023

We examine the mechanism of warming and tonifying kidney-yang recipe (WTKYR) in treating perimenopausal depression (PMD) using a network pharmacological approach. We identified the active ingredients and targets of WTKYR using the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. PMD targets were extracted from the Online Mendelian Inheritance in Man (OMIM), DisGeNET, and GeneCards databases. Venn diagrams were created with Venny to identify common WTKYR and PMD targets. A network diagram of WTKYR targets in PMD was created with Cytoscape to examine its core active ingredients. A protein–protein interaction (PPI) network of WTKYR’s targets was constructed using the STRING database, and its primary targets were evaluated using Network Analyzer and MCODE. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of essential WTKYR target genes were performed with Bioconductor. The LibDock program was applied to molecularly dock the core active ingredients of the WTKYR and the critical targets of PMD. The core WTKYR components for PMD identified were as oleic acid, beta-sitosterol, and phytodolor. The core WTKYR targets identified were the Jun proto-oncogene AP-1 transcription factor subunit (JUN), peroxisome proliferator-activated receptor gamma (PPARG), brain-derived neurotrophic factor (BDNF), caspase 3 (CASP3), and estrogen receptor 1 (ESR1) proteins and the neurotrophin, estrogen, serotonergic synapse, and cyclic adenosine monophosphate (cAMP) signaling pathways. The primary functions of these pathways include extensive neuroprotective and regenerative effects, regulation of 5-hydroxytryptamine (5-HT) metabolism, and participation in regulating the physiological functions of endogenous substances. These improve synaptic sensitivity, promote neuronal cell excitability, and enhance persistent firing in the medial and lateral entorhinal cortex. Molecular docking results show good affinity between the core active ingredients of WTKYR and the critical targets of PMD. This study predicted the essential WTKYR components and its primary targets and pathways for PMD treatment, and found that improving synaptic plasticity, participating in neuroelectrophysiological processes, and regulating related signaling pathways enhance PMD, which require confirmation by future cell or animal validation experiments.
RESEARCH ON 3D RECONSTRUCTION METHOD AND APPLICATION OF FOOD IN STROKE PATIENTS BASED ON RGB-D IMAGE
Authors: YUAN CHEN-DI , CHEN JIAN-KUN , WANG FEI , OUYANG JING-JIE , JING TAO , WANG XUE-FEI , YANG BO , SHAO ZE-GUO
Published: January 2023

RGB-D images can be used to build 3D models with high precision and efficiency. This paper introduces the method and principle of 3D modeling and the 3D reconstruction process of RGB-D images and analyzes KinectFusion and BundleFusion methods. Based on BundleFusion, this paper constructs a set of 3D reconstruction methods for stroke patients’ food and carries out 3D reconstruction experiments on watermelon, banana, orange, corn, and dish cold bitter gourd. With the actual measurement data validation, the banana’s average error rate of 3.95%; for watermelon, the average error rate is 3.89%; for grapes, the average error rate is 4.28%; for corn, apple, banana mixture composition, the average error rate is 2.61%, the average error rate of caramel treats is 3.48%, and the average error rate of pork floss bread is 2.85%. The average error rate of the hot and dry noodles is 1.85%, and the average error rate of the breakfast mix composition is 2.91%. The error rate in subsequent food volume calculation, quality estimation and calculation application is within the effective range of nutrients. It provides a technical basis and scientific basis for dietary intervention of stroke patients.
ANALYSIS OF THE EFFECTS OF WORKING POSITION ON MUSCLE FATIGUE DURING HEDGE PRUNING: A CROSS-SECTIONAL STUDY BASED ON CHINESE GARDEN WORKERS
Authors: YANG WANYING , LI SHUSEN , LI BO , LIU WENBO , NING FUYAO , GAO SONG
Published: January 2023

Occupational health is still in the developmental stage in China. There is a lack of focus on garden workers. Hedge pruning is one of garden workers’ main tasks, a common operation form in modern landscaping. Garden workers who operate the hedge trimmer generally suffer from work-related musculoskeletal disorders (WMSDs). This study aims to demonstrate which working condition causes the most muscle fatigue, evaluate work fatigue accurately, and reduce WMSDs in garden workers. One hundred and twenty garden workers were studied during six hedge pruning conditions using surface electromyography (sEMG) and a motion capture system. The sEMG of the erector spinae, trapezius, biceps brachii and brachioradialis muscle, and kinematic parameters was measured during the operation. The average standardized sEMG values of upper-limb and trunk muscles in different working conditions were analyzed using single-factor analysis of variance. In the six working conditions, the trunk inclination angle was the largest (40–50∘) in horizontal pruning of short hedges, and the load of erector spinae (39.31–39.62%) was the highest in this condition. Operators’ arms were above shoulder height in high hedge pruning, the shoulder joint angle and the elbow joint angle were generally larger, the load of trapezius (49.33–55.65%), biceps brachii (46.50–52.35%) and right brachioradialis (52.35%) was the highest in horizontal pruning of high hedges, and the load of left brachioradialis (40.91%) was the highest in vertical pruning of high hedges. Awkward working postures can lead to problems such as overwork of upper-limb and trunk muscles, representing a risk that increases occupational illness, injuries and chronic diseases among garden workers. Preventive measures are required to reduce the occurrence of excessive local muscle load, and prevent the occurrence of occupational diseases.
GAIT RECOGNITION OF ME-SVM BASED ON SINGLE ACCELEROMETER
Authors: CHANG YING , WANG LAN , LIN LINGJIE , LIU MING , XU LIUJIE
Published: January 2023

Gait recognition based on acceleration sensor signals is more suitable for complex environments than other signal-based methods, which can be used for data acquisition for gait recognition. However, most traditional methods only consider the position matching of multiple accelerometers, ignoring the comfort of the collector. In recent years, support vector machine (SVM) has been widely used in portrait recognition, language, and video processing. It has a flexible and powerful processing ability for nonlinear sequence input, and is a sparse and robust classifier. In this paper, we propose a multi-feature SVM algorithm ME-SVM, which is classified after multi-feature fusion. Usually, in the research of action recognition based on acceleration sensors, researchers classify from a single eigenvalue, but this paper optimizes this and further improves the recognition performance. Simulation and experimental results show that the algorithm has high accuracy and robustness.
AN IMPROVED DYNAMIC TIME WARPING METHOD COMBINING DISTANCE DENSITY CLUSTERING FOR EYE MOVEMENT ANALYSIS
Authors: WANG XIAOWEI , LI XUBO , WANG HAIYING , ZHAO WENNING , LIU XIA
Published: January 2023

Analyzing eye movement data to evaluate learning status has become crucial in intelligent education. The eye movement scanning path can directly or indirectly reflect changes in thinking patterns and psychological states. By analyzing the scanning path, we can explore the commonality and differences in learners’ eye movement behaviors and provide essential references for improving visual content and giving guidance. This paper first studies the time series representation and clustering of the learner’s scanning path under the same task. Then, the three learning states of concentration, mind-wandering, and information wandering are evaluated through the clustering results. Specifically, the improved DBA algorithm (iDBA) is proposed to extract group eye movement patterns, combined with the dynamic time warping (DTW) algorithm to calculate the similarity of scanning paths and determine the clustering seeds, while the distance density clustering (DDC) algorithm is used for clustering. Experiments show that time series-based eye movement pattern mining can identify group viewing behaviors. Meanwhile, clustering reveals different reading strategies and provides the ability to assess learning status.
Accurate object tracking by aligning and refining multiple predictions in Siamese networks
Authors: Lin Xiao , Hu Zhaohua , Liu Haonan
Published: January 2023

Siamese trackers, coupled with an efficient cross-correlation layer and benefiting from potent convolutional network technology, draw continuous interest in the field of visual object tracking. However, previous Siamese trackers may suffer from inconsistency of predictions that results in degraded performance during tracking: most of the prevalent Siamese networks employ two parallel branches for different subtasks whereas the corresponding outputs may mismatch with each other to some extent. To attack this issue, we advance a two-stage Siamese tracker named SiamPA for accurate object tracking. It employs center-based anchor-free heads in the first stage for preliminary predictions, meanwhile taking the carefully designed Prediction Alignment and Refinement module (PAR) as the second stage to refine the first-stage output. The PAR module is designed for Alignment and Refinement of multi-branch prediction, which works subtly in a mini-Siam manner. It is equipped with two different prediction branches: one used to align the multiple predictions induced in the first stage and the other to adjust coordinates of proposals. Extensive experiments are conducted to demonstrate the effectiveness of our SiamPA, showing that it achieves favorable performance on several prevalent benchmark datasets. Particularly, SiamPA achieves desirable performance while running at 67 FPS, which is far beyond real-time speed.
A Novel Strategy for Eliminating the Boundary Layer Effect in the Regularized Integral Identity in PIES for 2D Potential Problem
Authors: Zieniuk Eugeniusz , Szerszeń Krzysztof , Bołtuć Agnieszka
Published: January 2023

The paper presents a new strategy for improving the accuracy of solutions near the boundary in the integral identity associated with the parametric integral equation system (PIES) for two-dimensional (2D) potential problems. A significant reduction in accuracy in the zone close to the boundary, also known as the boundary layer effect, is directly associated with the nearly singular properties of kernels present in the integral identity. The paper shows that these singularities can be efficiently eliminated by regularizing the integral identity with the help of the so-called regularizing function with appropriate coefficients. The analyzed examples demonstrate a significant improvement in accuracy, where all integrals of the regularized integral identity are accurately calculated using low-order standard Gauss–Legendre quadrature. The proposed regularization algorithm is independent of the actual boundary shape, its representation and assumed boundary conditions.
Coupled VEM–BEM Approach for Isotropic Damage Modelling in Composite Materials
Authors: Lo Cascio Marco , Milazzo Alberto , Benedetti Ivano
Published: January 2023

Numerical prediction of composite damage behaviour at the microscopic level is still a challenging engineering issue for the analysis and design of modern materials. In this work, we document the application of a recently developed numerical technique based on the coupling between the virtual element method (VEM) and the boundary element method (BEM) within the framework of continuum damage mechanics (CDM) to model the in-plane damage evolution characteristics of composite materials. BEM is a widely adopted and efficient numerical technique that reduces the problem dimensionality due to its underlying formulation. It substantially simplifies the pre-processing stage and decreases the computational effort without affecting the solution’s accuracy. VEM is a recent generalization to general polygonal mesh elements of the finite element method that ensures noticeable simplification in the data preparation stage of the analysis, notably for computational micro-mechanics problems, whose analysis domain often features complex geometries. The numerical technique has been applied to artificial microstructures, representing the transverse section of composite material with stiffer circular-shaped inclusions embedded in a softer matrix. BEM is used to model the inclusions that are supposed to behave within the linear elastic range, while VEM is used to model the surrounding matrix material, developing nonlinear behaviours. Numerical results are reported and discussed to validate the proposed method.
Finite Block Method with Chebyshev Polynomials Applied to Cracked Plate in Functionally Graded Materials
Authors: Li X. , Aliabadi M. H. , Sladek J. , Sladek V. , Wen P. H.
Published: January 2023

The finite block method (FBM) with Chebyshev polynomials is developed in this paper for the functionally graded material (FGM) of two-dimensional fracture problem. The main idea is to divide domain into few blocks. By introducing the mapping technique, a block of quadratic type is transformed from Cartesian coordinate to normalised coordinate with eight seeds two dimensions. The differential matrices in physical domain are determined from that in the normalised transformed system. The accuracy of the FBM with Chebyshev polynomials is demonstrated with two examples and comparisons have been implemented with different numerical approaches.
Statistical Inference of Equivalent Initial Flaw Size Distribution for Fatigue Analysis of an Anisotropic Material
Authors: Zhuang Mengke , Morse Llewellyn , Khodaei Zahra Sharif , Aliabadi M. H.
Published: January 2023

A novel methodology for the fatigue life uncertainty quantification of anisotropic structures is presented in this work. The concept of the equivalent initial flaw size distribution (EIFSD) is employed to overcome the difficulties in small cracks detection and fatigue prediction. This EIFSD concept is combined with the dual boundary element method (DBEM) to provide an efficient methodology for modelling the fatigue crack growth. Bayesian inference is used to infer the EIFSD based on inspection data from the routine maintenance of the structure, simulated with the DBEM. A large amount of DBEM simulations were required for the Bayesian inference. Therefore, surrogate models are used as part of the inference to further improve computational efficiency. A numerical example featuring an anisotropic plate is investigated for demonstrating the proposed methodology. When considering a low level of uncertainty in the crack propagation parameters, an error of 0.12% was found between the estimated fatigue life obtained using the proposed method compared to actual fatigue life, and only 0.35% error when considering high level of uncertainty. The application of the estimated fatigue life can be used to determine an appropriate inspection interval for aircraft maintenance.
Aeroelastic Tailoring of Variable Stiffness Composite Laminated Quadrilateral and Circular Plates in Supersonic Flow Using Isogeometric Approach
Authors: Navardi Mohammad Mahdi , Shahverdi Hossein , Khalafi Vahid
Published: January 2023

In this study, a cubic NURBS-based isogeometric finite element method is developed to study the aeroelastic tailoring of variable stiffness composite laminated (VSCL) plates, including skew, skew-tapered, tapered, and circular shapes based on third-order shear deformation theory. Also, the first-order piston theory is employed to approximate aerodynamic loads with arbitrary yaw flow angles over the plate area to establish aeroelastic equations. The NURBS basis functions are then utilized to simulate exact geometries and estimate variable fields for discretizing governing equations by well-known isogeometric analysis. Finally, the free vibration and flutter analysis of a VSCL quadrilateral and circular plate will be presented via the obtained eigenvalue problem. The achieved results are compared with the available results in the literature to prove the accuracy and validity of the present method. The effect of different parameters such as the flow yaw angle, end and middle-length fiber orientation, longitudinal to transverse Young’s modulus ratio, geometric shape, boundary conditions, and turning symmetric layup to asymmetric layup is carried out on the critical flutter aerodynamic pressure and natural frequencies.
Using optical coherence tomography images to evaluate fungal growth in reline resins
Authors: Aquino Mayra M. , Maior Caio B. S. , Lins Nathália A. E. , Mota Cláudia C. B. O. , Nascimento Patricia L. A. , Gomes Anderson S. L.
Published: January 2023

As changes in hard or soft oral tissues normally have a microbiological component, it is important to develop diagnostic techniques that support clinical evaluation, without destroying microbiological formation. The optical coherence tomography (OCT) represents an alternative to analyze tissues and microorganisms without the need for processing. This imaging technique could be defined as a fast, real-time, in situ, and non-destructive method. Thus, this study proposed the use of the OCT to visualize biofilm by Candida albicans in reline resins for removable prostheses. Three reline resins (Silagum-Comfort, Coe-Comfort, and Soft-Confort), with distinct characteristics related to water sorption and fungal inhibition were used. A total of 30 samples (10 for each resin group) were subjected to OCT scanning before and 96 h after inoculation with Candida albicans (URM 6547). The biofilm analysis was carried out through a 2D optical Callisto SD-OCT (930 nm) operated in the spectral domain. Then, the images were preprocessed using a [Formula: see text] Gaussian filter to remove the noise, and then Otsu binarization, allowing segmentation and pixel counting. The layer’s biofilm formed was clearly defined and, indeed, its visualization is modified by water sorption of each material. Silagum-Comfort and Soft-Confort showed some similarities in the scattering of light between the clean and inoculated samples, in which, the latter samples presented higher values of light signal intensity. Coe-Comfort samples were the only ones that showed no differences between the clean or inoculated images. Therefore, the results of this study suggest that OCT is a viable technique to visualize the biofilm in reline materials. Because findings in the literature are still scarcely using the OCT technique to visualize biofilm in reline resins, further studies are encouraged. It should not contain any references or displayed equations.
L Band Phased Array Feed Noise Figure and Radiation Efficiency Measurement with the Antenna Y Factor Method
Authors: Burnett Mitchell C. , Buck David , Ashcraft Nathaniel , Ammermon Spencer , Jeffs Brian D. , Warnick Karl F.
Published: January 2023

The noise performance of a high sensitivity, wide-field astronomical phased array feed receiver can be characterized by measurements using the antenna Y factor method. These measurements are used to determine figures of merit for an active array receiver. Antenna elements for the Advanced L Band Phased Array Camera for Astronomy (ALPACA) were measured using the antenna Y factor method to determine the active array and receiver noise figure, the antenna loss, receiver equivalent noise temperature, and radiation efficiency of the system over its 500[Formula: see text]MHz operating bandwidth. The completed ALPACA instrument will feature a fully cryogenic design with both the low-noise amplifiers and array elements cryogenically cooled. The uncooled performance measurements from the antenna Y factor method are used to extrapolate the elements cryogenic radiation efficiency and antenna loss showing that it is expected that the elements will contribute less than 1 K to the overall system noise temperature. These results validate the antenna Y factor method to measure key antenna parameters such as the antenna radiation efficiency and show that the instruments front-end array and electronics meets expected performance targets.
An Image Auto Guider System for Kodaikanal Tower Tunnel Telescope
Authors: Mathur Harsh , Thulasidharen K. C. , Pruthvi Hemanth , Nagaraju K. , Rajalingam M.
Published: January 2023

The Kodaikanal Tower Tunnel Telescope (KTT) is a three-mirror Coelostat-based Solar telescope. An inherent variable image drift is present in the KTT which is detrimental to observations particularly to slit-based spectroscopic and spectropolarimetric observations. An image Auto Guider system has recently been installed at KTT to arrest the image drift based on sensing the image limb. The image’s limb position on the image plane is sensed using a two-segment photodiode sensor in North–South and East–West directions. Feedback is given to the second mirror of Coelostat, which tilts, causing the image to move on the image plane. This paper discusses instrumental setup, calibration, and testing of the Auto Guider system at KTT. The Auto Guider system is robust and capable of arresting image drifts up to 55[Formula: see text]arcsec[Formula: see text][Formula: see text], which is much higher than the typically observed drifts (maximum 7[Formula: see text]arcsec[Formula: see text][Formula: see text]) at KTT with a precision of [Formula: see text][Formula: see text]arcsec.
DNA Methylation Analysis of the SHOX2 and RASSF1A Panel Using Cell-Free DNA in the Diagnosis of Malignant Pleural Effusion
Authors: Zhang Nana , Liu Zichen , Li Kun , Xing Xuya , Long Chaolian , Liu Fangchao , She Bin , Che Nanying
Published: January 2023

Objectives. The differential diagnosis of pleural effusion (PE) is a common but major challenge in clinical practice. This study aimed to establish a strategy based on a PE-cell-free DNA (cfDNA) methylation detection system for the differential diagnosis of malignant pleural effusion (MPE) and benign pleural effusion (BPE). Methods. A total of 104 patients with PE were enrolled in this study, among which 50 patients had MPE, 9 malignant tumor patients had PE of indefinite causes, and the other 45 patients were classified as benign controls. The methylation status of short stature homeobox 2 (SHOX2) and RAS association domain family 1, isoform A (RASSF1A) was detected using PE-cfDNA specimens by real-time fluorescence quantitative PCR. Total methylation (TM) was defined as the combination of the methylation levels of SHOX2 and RASSF1A. The electrochemiluminescence immunoassay was applied to evaluate the levels of multiple serum tumor markers. Results. The PE-cfDNA methylation status of either SHOX2 or RASSF1A was much higher in MPE samples than in benign controls. The combination of SHOX2 and RASSF1A methylation in PE yielded a diagnostic sensitivity of 96% and a specificity of 100%, respectively. When compared with the corresponding serum tumor marker detection results, TM showed the highest diagnostic efficiency (AUC = 0.985). Furthermore, the combination of the SHOX2 and RASSF1A methylation panels using PE-cfDNA could apparently improve the differential diagnostic efficacy of BPE and MPE and could help compensate for the deficiency of cytology. Conclusions. Our results indicated that SHOX2 and RASSF1A methylation panel detection could accurately classify BPE and MPE diseases and showed better diagnostic performance than traditional serum parameters. The SHOX2 and RASSF1A methylation detection of PE-cfDNA could be a potentially effective complementary tool for cytology in the process of differential diagnosis. In summary, PE-cfDNA could be used as a promising non-invasive analyte for the auxiliary diagnosis of MPE.
Peripheral Eosinophil Count Associated with Disease Activity and Clinical Outcomes in Hospitalized Patients with Lupus Nephritis
Authors: Liu Ruihua , Peng Yuan , Ye Hongjian , Xia Xi , Chen Wei , Huang Fengxian , Li Zhijian , Yang Xiao
Published: January 2023

Introduction: The aim of this study was to evaluate the association of peripheral eosinophil (EOS) count with disease activity and kidney outcomes in lupus nephritis (LN) patients. Methods: A total of 453 hospitalized and biopsy-proven LN patients at our hospital from 2006 to 2013 were enrolled, of which 388 patients had repeated measurements of EOS. Relationships were explored between average EOS and disease activity at baseline, using the systemic lupus erythematosus disease activity (SLEDAI) and activity index (AI) on kidney biopsy. Follow-up data were available through December 2016. The primary outcome measure was a composite of doubling of serum creatinine and end-stage kidney disease after a median follow-up of 51 months. Results: The mean age of the enrolled 388 LN patients was 33.1 ± 10.8 years old, and 335 (86%) were female. The median average peripheral EOS count was 0.033 (0.015–0.057) ×109/L. Mean AI and SLEDAI score were 6.8 ± 2.5 and 14.9 ± 5.4, respectively. Logistic regression models showed that decreased average EOS was independently associated with higher AI (≥6) and higher SLEDAI (≥15) (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.90–0.97; and OR 0.96, 95% CI: 0.93–0.99, respectively). There was a parabolic relationship between average EOS and the primary outcome, with hazard ratio (HR) > 1 for both levels ≤0.033 and >0.16 × 109/L. Conclusion: Lower EOS count was independently associated with severe disease activity and kidney progression in LN.
SARS-CoV-2 Infection of Young Infants during the Omicron Wave: A Case Series
Authors: Sehr Ansari Najmus , Watson Douglas C. , Campbell Douglas M. , Sarhan Mohammed A. , Bitnun Ari , Gauda Estelle B.
Published: January 2023

We describe the clinical course of 4 infants infected with severe acute respiratory syndrome coronavirus 2. All were admitted to our tertiary care neonatal intensive care unit during the Omicron variant wave in our region. All 4 infants, who were less than 3 months of age, including three born prematurely, presented with critical illness. However, their clinical presentation varied considerably. Of them, two infants presented with apnea, one with respiratory distress, and one with gastrointestinal manifestation. Our experience with these four infants provides evidence for a severe form of disease and varied clinical presentation in neonates and young infants speculated to be infected with Omicron variant.
A Qualitative Study Investigating the Current Practices, Obstacles, and Needs of Enteral Nutrition Support among Registered Dietitians Managing Non-Critically Ill Hospitalized Patients in Riyadh, Saudi Arabia
Authors: Alsoqeah Fatimah , Alyumni Rabaa , Alruwaili Nawaf , Aldubayan Khalid
Published: January 2023

Introduction: Despite the wide availability of international guidelines that direct enteral nutrition practices, no recommendations or guidelines are tailored specifically for the unique healthcare environment in Saudi Arabia. Specifically tailored national guidelines are considered essential evidence that should be developed and followed. However, understanding the current practices, local needs, and gaps is important to facilitate the process of developing a practical national guideline. Methodology: In this qualitative study, focus groups using a structured interview technique were conducted to gain an in-depth understanding of the current enteral nutrition practices and related needs/obstacles from 24 registered dietitians handling non-critically ill patients. The recorded sessions were transcribed, and then themes were identified via coding analysis. In addition, the inter-rater agreement of the data’s themes was evaluated. Results: Five focus group sessions that consisted of 24 participants (3 males and 21 females) working in private and governmental hospitals (18 governmental and 6 private) in Riyadh city were conducted. Ten enteral nutrition practice-related themes for non-critically ill patients were identified via coding analysis, in addition to four obstacle-related themes and four need-related themes. Conclusion: Non-critically ill patients represent the most significant majority of hospitalized patients. Therefore, it is recommended for the relevant regulatory authorities to develop national enteral nutrition guidelines and policies that guarantee consistent and sustainable care, along with improving the health outcomes for this population.
Lebanon’s Parliament System as a Form of Institutionalized Hybridity
Authors: Paterson James , MacQueen Ben
Published: January 2023

This article presents the Lebanese parliament as a form of institutionalized hybridity that offers a modicum of popular participation through highly regulated and moderated channels. It argues that the procedural nature of Lebanon’s electoral system is one that is largely, if not entirely, underscored by a closed elite bargaining process and is driven by elite preferences. This dynamic is a by-product of a power-sharing arrangement that ostensibly balances sectarian concerns, but in reality creates a disparity between political elites and the individuals within those sects which the consociational arrangement purports to include. However, this system has also created and reinforced challenges to its rule, particularly from below. With that in mind, this article highlights the evolving interactions between the entrenched, elite dominated, political system and popular protest movement and outlines how recent patterns of popular unrest present more fundamental critiques of the parliament and its central role in Lebanese politics.
Tidying things up: Tropicosa, a new Neotropical wolf spider genus (Araneae: Lycosidae: Lycosinae)
Authors: PAREDES-MUNGUÍA WILLIAMS , BRESCOVIT ANTONIO D. , TEIXEIRA RENATO A.
Published: January 2023

The new genus Tropicosa is proposed based on species of some controversial Neotropical genera of lycosids. These spiders present a longitudinal dark stripe over the sternum in both sexes, median apophysis sinuous, tegular lobe evidently sclerotized and the epigyne with median septum anteriorly expanded and with a parallel, triangular hood. We transfer Alopecosa moesta (Holmberg), Schizocosa chelifasciata (Mello-Leitão) and Lycosa thorelli (Keyserling) to Tropicosa gen. nov. and describe one new species, Tropicosa baguala sp. nov. Likewise, Arctosa bogotensis (Keyserling) is synonymized with Tropicosa thorelli (Keyserling) comb. nov., and Lycosa langei Mello-Leitão with T. chelifasciata (Mello-Leitão) comb. nov. based on examined types. All the four species proposed as members of Tropicosa gen. nov. have South American distribution.