Variable Structure Research Articles

Harnessing genetic diversity in Sudanese sorghum wild relatives for stay-green drought tolerance via microsatellite (SSR) marker assessment

AbstractSudan is the birthplace of sorghum, and vast genetic diversity exists among its wild relatives. To assess the genetic potential of Sudan wild sorghum accessions, we used 41 stay-green-specific microsatellite (SSR) markers to analyze the genetic variability and population structure of 256 accessions. Overall, 17 SSR markers were polymorphic, with 55 alleles on average 3.3 per locus. The polymorphic information content (PIC) ranged from 0.49 to 0.57, with an overall mean of 0.53, indicating the potential of these markers for capturing the genetic construction of wild sorghum. Linkage disequilibrium analysis identified the two most informative markers, Xcup05 and Xtxp212. Accordingly, the Nei gene diversity of the populations varied from 0.032 to 0.127, with an overall mean of 0.083. Molecular variance analysis (AMOVA) demonstrated that 99% and 1% of the genetic variations were within and among populations (Fst = 0.066; P 0.001), respectively. However, gene flow (Nm) values varied from 0.058 in populations 1 and 2 to 1.018 in populations 2 and 3. Neighbor-joining trees identified from 21 Sudanese wild sorghum accessions clustered closely to the universally drought-tolerant landrace B35. Structural analysis generated the highest Delta K value (58.2) at K = 2, revealing two distinct subpopulations. While this work provides valuable information about the potential of sorghum wild relatives from Sudan as sources for stay-green drought tolerance, further research should be directed toward identifying the exact mechanisms and genes underlying this stay-green trait using advanced molecular omics techniques. In conclusion, this study highlights the potential role of Sudanese sorghum accessions as reservoirs of ready-to-use stay-green genes for the design of climate-resilient sorghum cultivars in drought-prone areas of Sudan and beyond. However, these wild relatives would require extensive pre-breeding and validation efforts before their genes can be effectively incorporated into elite cultivars.

Research on Voltage Prediction Using LSTM Neural Networks and Dynamic Voltage Restorers Based on Novel Sliding Mode Variable Structure Control

To address the issue of uncertainty in the occurrence time of voltage sags in power grids, which affects power quality, a voltage state prediction method based on LSTM neural networks is proposed for predicting voltage states. For the problem of quickly and accurately compensating for voltage sags, a DVR system based on a new approach law of sliding mode variable structure control is proposed, which significantly reduces chattering, improves response speed, and enhances the robustness of the system. The stability of the system is proven based on Lyapunov stability theory. Simulation experiments are conducted to analyze the voltage state prediction effect based on the LSTM neural network and the compensation effect of the novel reaching law of sliding mode variable structure control under different levels of voltage sag, validating the effectiveness and correctness of the proposed solution.

The Variability Structure Function of the Highest-Luminosity Quasars on Short Timescales

Abstract The stochastic photometric variability of quasars is known to follow a random-walk phenomenology on emission timescales of months to years. Some high-cadence restframe optical monitoring in the past has hinted at a suppression of variability amplitudes on shorter timescales of a few days or weeks, opening the question of what drives the suppression and how it might scale with quasar properties. Here, we study a few thousand of the highest-luminosity quasars in the sky, mostly in the luminosity range of Lbol=[46.4, 47.3] and redshift range of z = [0.7, 2.4]. We use a dataset from the NASA/ATLAS facility with nightly cadence, weather permitting, which has been used before to quantify strong regularity in longer-term restframe-UV variability. As we focus on a careful treatment of short timescales across the sample, we find that a linear function is sufficient to describe the UV variability structure function. Although the result can not rule out the existence of breaks in some groups completely, a simpler model is usually favoured under this circumstance. In conclusion, the data is consistent with a single-slope random walk across restframe timescales of Δt = [10, 250] days.

Research on Parametric Design and Mechanical Performance of Variable Cross-Section Diamond Lattice Structures

Research on Parametric Design and Mechanical Performance of Variable Cross-Section Diamond Lattice Structures

Effect of thermocycling on flexural strength of dental CAD/CAM ceramics of variable thicknesses and structures: an in vitro study

Background This study examined the effect of thermocycling on the flexural strength properties of four CAD/CAM ceramic materials at different thicknesses. Methods Four CAD/CAM ceramics of different types: advanced lithium disilicate (ALD), zirconia-reinforced lithium silicate (ZLS) lithium disilicate (LD), and leucite reinforced (LE), and at three varying thicknesses 0.5, 1.0 and 1.5 mm were examined. After subjecting all specimens to 5000 thermomechanical cycles, flexural strength was determined using a universal testing apparatus. Scanning electron microscopy (SEM) was employed for analysis. Two factorial ANOVA models assessed the association of different factors (ceramic type and thickness) with flexural strength and elastic modulus. The 95% confidence intervals (CIs) and adjusted means were computed. A p-value < 0.05 was designated significant. Results ZLS exhibited the highest flexural strength at 1.5 mm thickness, while LD showed the highest Young’s modulus of elasticity. The lowest flexural strength was observed in the 0.5 mm thickness group. There were notable variations in flexural strength across all ceramic materials, with the highest adjusted mean strength in the ZLS group, ALD, LD, and LE, respectively. Additionally, significant differences were noted in ceramic thickness, with 1.5 mm thickness showing the highest strength and 0.5 mm thickness the lowest. Conclusions Ceramic material thickness significantly impacts flexural strength, with 1.5 mm thickness deemed suitable for posterior restorations. Ceramic materials with zirconia fillers or matrix demonstrated higher flexural strength than other ceramics.

Assessing Genetic Variability and Population Structure of Alnus glutinosa (Black Alder) in Kazakhstan Using SSR Markers

Alnus glutinosa plays a crucial role in flood control, riverbank stabilization, and water purification. Recognized for its ecological significance, it is listed in the Red Book of Kazakhstan. This study investigated the genetic variability of A. glutinosa populations in Kazakhstan, analyzing 78 trees from seven populations in the Bayanaul mountain forest massif and the northern Turgay regions using 12 SSR markers. The study identified an average of 6.3 alleles and 2.783 effective alleles, as well as observed and expected heterozygosities of 0.570 and 0.562, respectively, reflecting genetic diversity. Among the populations, KS1 (northern Turgay) and PVL3 (Bayanaul) displayed the highest diversity, while PVL5 (Bayanaul) showed slightly lower diversity. The analysis of molecular variance results indicated that 86% of the genetic diversity occurred within populations, with 14% attributed to differences between populations. A UPGMA tree based on Nei’s genetic distance revealed three distinct clusters, suggesting geographically structured genetic variability in A. glutinosa populations.

Regularities of variability in the anatomical structure of the left atrium in persons of different body types

Attention of cardiac surgeons and arrhythmologists are the ostia of the pulmonary veins, which are the place of the formation of trigger points during the development of atrial fibrillation. Data on the variability of the anatomical structure of the left atrium are scarce and are often contradictory, which makes it relevant to study the variability of the structure of the left atrium in the aspect of constitutional anatomy. Purpose of the study: to establish patterns of variability in the structure of the left atrium, taking into account body type. Materials and methods: The study is based on an analysis of the results of contrast-enhanced MSCT of the heart in 105 apparently healthy individuals. Results: Analyzing the data obtained on the types of confluence of the pulmonary veins (PV) into the left atrium, it was found that in individuals of all body types, the flow of the 4-ostia pulmonary veins into the cavity of the left vertex occurs in the largest percentage of cases. Among the examined individuals, the following 7 variants of the anatomical structure of the left atrium with different frequencies of occurrence were identified: 1) typical confluence of the PV in combination with the oval shape of the orifice of the left appendage; 2) typical confluence of the PV in combination with the round shape of the mouth of the left atrium (LA) appendage; 3) confluence of the PV with a common collector on the left side in combination with the round shape of the mouth of the LA appendage; 4) confluence of the PV with a common collector on both sides in combination with the oval shape of the mouth of the LA appendage; 5) confluence of the PV with a common collector on both sides in combination with the round shape of the mouth of the LA appendage; 6) typical confluence of the PV in combination with the accessory pulmonary vein and the oval shape of the orifice of the LA appendage; 7) typical confluence of the PV in combination with the accessory pulmonary vein and the round shape of the auricle.

Smart Factory Operation Management System and Innovation in the Era of Smart Manufacturing

This study is dedicated to the innovative research of smart factory operation management systems in the era of smart manufacturing. Against the backdrop of the rapid evolution of the information revolution, smart manufacturing, represented by a new generation of information technologies such as mobile Internet, big data, and artificial intelligence, is rapidly emerging. As an information-physical fusion system, smart factories interpenetrate physical and virtual resources by interweaving multi-scale production systems, forming an open, complex giant system with multiple levels and dimensions. It is found that smart factories face a complex and variable structure, and their production and operations involve a large number of cross-domain, cross-industry, and cross-region manufacturing resources, requiring the establishment of a new operation management system framework and breakthroughs in key theories and methods. This study provides comprehensive and in-depth theoretical and technical support for constructing a smart factory operation management system. It lays the foundation for the smart upgrading of the manufacturing industry.

The analysis of Gurney flap applications for autonomous underwater gliders

ABSTRACT In this paper, the Gurney flap structure (GF) from aeronautical research was applied to underwater gliders for improving the lift-to-drag ratio. Firstly, the numerical simulation method was used to verify the lift enhancement principle of the GF structure and the feasibility of its application to autonomous underwater gliders (AUG). Secondly, the performance of different GF was simulated and analysed, and a variable GF structure was proposed with the requirements of the operating modes. The GF parameters were optimised by a genetic algorithm. The results show that the performance of GF in water is similar to that in air, so it is feasible to apply GF to AUG. When the height of GF is close to the turbulent boundary layer of the trailing edge of the wing, the lift-to-drag ratio is significantly improved, especially in the range of small angle of attack and the maximum increase is up to 30%.

Dew Point Characteristics at Synoptic Stations in Northern Benin

The dew point temperature is a very important parameter for hydro and agro-climatological research. This work studied the temporal variability of dew point temperature in Northern Benin. The dew point data comes from three synoptic stations in Northern Benin and covers the period from January 1980 to February 2019. After, correction and homogenization of the data, statistical methods are employed to analyze its structure, distribution, and temporal variability. The average of the dataset is 16.607°C with a standard deviation of 6.871 and a coefficient of variation of 0.414. The distribution is negatively skewed without extreme values, with an interquartile range of 10.284. The analysis by days of month indicates an irregular change in values at the beginning of month. The days of week show a minimum at the beginning and a maximum at the end of week. The analysis of dew point temperature data by months of the year shows a bell-shaped distribution with a plateau covering the months from May to September. The average dew point temperature has been increasing over the years. The data also describe a non-stationary periodic series approved by statistical tests. The absence of an inflection point in the data and in the trend means that the distribution is evolving and cyclical but not regular.

New mitochondrial gene order arrangements and evolutionary implications in the class Octocorallia.

The complete mitochondrial genomes of octocorals typically range from 18.5 kb to 20.5 kb in length and include 14 protein-coding genes (PCGs), two ribosomal RNA genes and one tRNA. To date, seven different gene orders (A-G) have been described, yet comprehensive investigations of the actual number of arrangements, as well as comparative analyses and evolutionary reconstructions of mitochondrial genome evolution within the whole class Octocorallia, have been often overlooked. Here, we considered the complete mitochondrial genomes available for octocorals and explored their structure and gene order variability. Our results updated the actual number of mitochondrial gene order arrangements so far known for octocorals from 7 to 14 and allowed us to explore and preliminarily discuss the role of some of the structural and functional factors in the mitogenomes. We performed comparative mitogenomic analyses on the existing and novel octocoral gene orders, considering different mitogenomic structural features such as genome size, GC percentage, AT and GC skewness. The mitochondrial gene order history mapped on a recently published nuclear loci phylogeny showed that the most common rearrangement events in octocorals are inversions, inverted transpositions and transpositions. Furthermore, gene order rearrangement events were restricted only to some regions of the tree. Overall, different rearrangement events arose independently and from the ancestral and most common gene order, instead of being derived from other rearranged orders. Finally, our data demonstrate how the study of mitochondrial gene orders can be used to explore the evolution of octocorals and in some cases can be used to assess the phylogenetic placement of certain taxa.

Altai Osmans of the Genus Oreoleuciscus and African Barbs of the Barbus intermedius Complex: the Common Patterns of Morphological Differences Between Piscivorous and Non-Piscivorous Forms under Sympatry Conditions

In populations of fish species of the same and of different systematic groups living in lakes of the same and of different continents the patterns of differences in factor loadings of the considered parameters of the morphology of the jaw apparatus and neurocranium on the main vectors of variability in comparison of piscivorous and non-piscivorous ecological forms almost coincides. It is shown that in the Altai osmans of the Oreoleuciscus potanini species in two lakes of the Central Asian Closed Basin, the structure of differences is almost identical to the structure of differences between the piscivorous and non-piscivorous forms of the barbs of the Barbus intermedius complex sensu Banister (1973) complex in the African Lake Tana. At the same time, the structure of the differences between the piscivorous and non-piscivorous forms of another species of Altai Osmans Oreoleuciscus humilis in a lake located in another part of the Central Asian Closed Basin differs significantly from the structure of differences in ecological forms of both the O. potanini species and the B. intermedius complex. It is assumed that the following explanation may be given for the revealed difference in the variability of Osmans in the studied water bodies. In the African lake Tana and Mongolian lakes Bayan and Khar-Us, the structure of differences reflects the already established situation of stationary coexistence of piscivorous and non-piscivorous forms in one water body. Whereas the structure of variability in the periodically drying Mongolian lake Lake Orog reflects not an established situation, but an incomplete process of its formation, interrupted over and over again by the death of the lake population in the next drought period.

Generalized synchronization of a class of heterogeneous drive response networks with time delay based on variable structure control

Generalized synchronization of a class of heterogeneous drive response networks with time delay based on variable structure control

Aircraft joint structure lightweight design

PurposeThe purpose of this article is to carry out a lightweight design of the joint structure according to the service condition of the joint.Design/methodology/approachThe finite element analysis techniques are used along with the variable density structure topology optimization method, the multi-island genetic algorithm for structural dimension optimization and the fatigue life analysis method.FindingsUtilizing the topology optimization method and size optimization method, the mass of the optimized model for the A100 material model is 9.67 kg. Compared to the pre-optimized model, the mass decreases by 8.23 kg, representing a weight reduction of 46.0% in the optimized model; the fatigue life of the aircraft joint is predicted to be a maximum of 1,460,017 cycles.Originality/valueThe originality of this study is that it provides new design ideas for the lightweight design of aircraft load-bearing structures.

Numerical and Experimental Study of a Wearable Exo-Glove for Telerehabilitation Application Using Shape Memory Alloy Actuators

Hand paralysis, caused by conditions such as spinal cord injuries, strokes, and arthritis, significantly hinders daily activities. Wearable exo-gloves and telerehabilitation offer effective hand training solutions to aid the recovery process. This study presents the development of lightweight wearable exo-gloves designed for finger telerehabilitation. The prototype uses NiTi shape memory alloy (SMA) actuators to control five fingers. Specialized end effectors target the metacarpophalangeal (MCP), proximal interphalangeal (PIP), and distal interphalangeal (DIP) joints, mimicking human finger tendon actions. A variable structure controller, managed through a web-based Human–Machine Interface (HMI), allows remote adjustments. Thermal behavior, dynamics, and overall performance were modeled in MATLAB Simulink, with experimental validation confirming the model’s efficacy. The phase transformation characteristics of NiTi shape memory wire were studied using the Souza–Auricchio model within COMSOL Multiphysics 6.2 software. Comparing the simulation to trial data showed an average error of 2.76°. The range of motion for the MCP, PIP, and DIP joints was 21°, 65°, and 60.3°, respectively. Additionally, a minimum torque of 0.2 Nm at each finger joint was observed, which is sufficient to overcome resistance and meet the torque requirements. Results demonstrate that integrating SMA actuators with telerehabilitation addresses the need for compact and efficient wearable devices, potentially improving patient outcomes through remote therapy.

On the Mathematical Background of Sliding Mode-Based Friction Compensation of a Micro-Telemanipulation System

Modeling of various phenomena in engineering work is always a kind of simplification of real processes, aiming at a model where a certain level of mathematical theory and computational procedures is sufficient. If the complexity of the required theory corresponds to the general mathematical competence of engineers, then technical problems can be treated separately in engineering (or physical) models without regard to the mathematical background. However, in some advanced engineering fields, the harmonized development of engineering and mathematical models and toolboxes is necessary to find efficient solutions. For example, modeling variable structure systems in ideal sliding mode requires a mathematical toolbox that goes far beyond general engineering competence through the theory of discontinuous right-hand-side differential equations. Although sliding mode control is popular in practice and the concept of sliding mode allows a significant reduction of model complexity, its exact mathematical description is rarely encountered. The problem of friction compensation of a micro-telemanipulator using sliding mode control demonstrates a harmonized application of the mathematical and engineering approaches. Based on Filippov’s theory, the ideal sliding mode can be discussed. Although an ideal system cannot be implemented in reality, the real systems can be kept close enough to it; therefore, the discussion of the solution of the ideal model is important for practical applications. Although several elements of the topic are available in the literature, in this paper a unique complex approach is given for users of sliding mode control with experimental considerations, different engineering models, and codes. The paper concludes that sliding mode control is a case where engineering and mathematical modeling are inseparable and requires the competence of both fields.

The structure of individual variability of palynomorphological features of the genus <i>Cestrum</i> (Solanaceae). Typical form and deviations (morphoses)

The structure of individual variability of palynomorphological features of the genus <i>Cestrum</i> (Solanaceae). Typical form and deviations (morphoses)

System modeling and fuzzy adaptive PI sliding-mode control of a novel ship-mounted cable-based bulkhead cleaning robot

Ship cleaning poses significant risks and consumes considerable time, primarily due to the irregular hull surface geometry and the unpredictable ship motion induced by wave excitation. To address this challenge and achieve efficient, autonomous cleaning, a spatial variable structure cable-based bulkhead cleaning robot (SC-R) is proposed. Unlike traditional cable-driven parallel mechanisms (CDPMs), SC-R operates in a non-inertial frame, whereby its motion is subject to continuous and unpredictable ship motion. Consequently, SC-R exhibits intricate dynamic characteristics, posing a significant hurdle for controller design. To solve this problem, a sliding-mode controller is proposed for SC-R. Specifically, the dynamic model of SC-R, which includes ship motion and various disturbing forces, is systematically established using the Newton-Euler method. Furthermore, a fuzzy adaptive PI sliding-mode controller (FAPI-SMC) is specifically proposed to enhance the convergence speed and robustness of SC-R. The stability of the closed-loop system is analyzed using Lyapunov theory, and the tracking error is proved to be eventually bounded. Finally, the availability of this theory is confirmed by simulation and experiment. It is shown that FAPI-SMC can achieve a satisfactory control effect in practice.

Correlates of spatial structure variability in Bushehr port-city: A comprehensive analysis using fuzzy cognitive mapping methodology

It is critical for urban and regional planners to examine spatial relationships and interactions between a port and its surrounding urban areas within a region’s spatial structure. This paper seeks to develop a targeted framework of causal relationships influencing the spatial structure changes in the Bushehr port-city. Hence, the study utilizes Fuzzy Cognitive Maps (FCMs), a computational technique adept at analyzing complex decision-making processes. FCMs are employed to identify concepts that act as drivers or barriers in the spatial structure changes of Bushehr port-city, thereby elucidating the causal relationships within this context. Additionally, the study evaluates these concepts’ relative significance and interrelationships. Data was collected through interviews with ten experts from diverse backgrounds, including specialists, academics, policymakers, and urban managers. The insights from these experts were analyzed using FCMapper and Pajek software to construct a collective FCM, which depicts the influential and affected concepts within the system. The resulting collective FCM consists of 16 concepts, representing the varied perspectives and expertise of the participants. Among these, the concepts of management and planning reform, economic growth of the city-port, and port development emerged as the three most central concepts. Moreover, the effects of all influential concepts on the spatial structure change in Bushehr port-city were evaluated through simulations conducted across four different scenarios. The analysis demonstrated that the system experiences the most significant impact under the fourth scenario, where the most substantial changes are observed in commercial and industrial growth and the planning of port-city separation policies.

Predictors of dietary orientation among registered dietitians and dietetics students

ABSTRACT Interest has arisen regarding different dietary approaches, namely prescriptive vs non-dieting approaches. Nonetheless, evidence on which individual factors orient professionals toward either approach is currently lacking for dietetics students and registered dietitians (RDN). For this reason, the present study aimed at investigating personal and interpersonal factors associated with the adoption of such approaches in dietary practice. This cross-sectional observational study involved 174 participants through an online survey (response rate 74.41%, n = 128). Participants were recruited from two universities in Italy, encompassing both RDNs and dietetics students. The sample was then divided by self-reported dietary approach orientation and group differences were explored. Personal (such as previous history of dieting, personality factors, intuitive eating, eating experiences) and interpersonal factors (like areas of work interest, years of clinical expertise) potentially influencing dietary orientation were investigated. Group differences were estimated by Analysis of Covariance (ANCOVA) for continuous variables, after adjustment for age and gender, and by Chi-squared tests for categorical variables. Moreover, network structures for psychometric variables were estimated for both groups, employing a mixed graphical model, and computing a comparison between groups after bootstrapping (edge invariance test, n = 5,000). Results showed that openness to experience (F-value: 3.989 p-value: <0.05) and intuitive eating (F-value: 9.836, p-value: <0.01) were higher among participants which oriented toward non-dieting approaches. RDNs with more years of clinical experience (p-value: 0.004) and working within the field of eating disorders (p-value: <0.001) were more likely to be oriented toward non-dieting approaches. Current findings suggest that personal and interpersonal factors shape dietary orientations.