Rank Correlation Method Research Articles

Soil moisture content and its temporal stability in an arid aerial seeding afforestation area after 30 years vegetation restoration in China

Soil moisture is a critical factor for vegetation restoration in arid regions. Poorly planned artificial sand-fixing vegetation systems often exacerbate soil moisture depletion, leading to further degradation. In this study, soil moisture content at various depths was continuously monitored from June to October 2023 in four key community plots—Corethrodendron scoparium, Calligonum mongolicum, and Artemisia ordosica, and bare sand—in a 31-year-old revegetated area located on the northeastern edge of the Tengger Desert. We analyzed the distribution and dynamic changes of soil moisture across the different and evaluated its temporal stability. The representative soil moisture depth was determined by using the coefficient of determination (R2) and the Nash-Sutcliffe efficiency (NSE). The results showed significant differences in soil moisture among the four plots. The bare sand plot had the highest soil water storage in the 0-200 cm layer, at 46.37 mm. In contrast, the Corethrodendron scoparium, Calligonum mongolicum, and Artemisia ordosicaa plots had similar soil water storage values ranging from 33.50 to 33.67 mm, indicating that vegetation restoration has increased soil moisture absorption by an average of 27.4%. Analysis using relative difference and Spearman rank correlation methods revealed varying levels of temporal stability in soil moisture across different soil depths and plots. The Corethrodendron scoparium and bare sand plots showed higher temporal stability compared to the Calligonum mongolicum and Artemisia ordosica plots. The representative depths of temporal stability for the four plots were determined to be 100 cm, 150 cm, 20 cm, and 100 cm, respectively.

Effective Pest Control Through Natural Predators: A Dynamical Plant–Pest–Predator Model

The impact of pests on crop yield is a significant worry for farmers, and finding an effective strategy to control insect population growth has become a pressing matter. This study explores the dynamic analysis of a model that incorporates natural predators to control crop pests. In the research, an analysis is conducted on the model’s positivity and boundedness, followed by an examination of the existence and stability of the equilibrium points. The study focused on analyzing bifurcations at a biologically feasible equilibrium point. The parameters considered for bifurcation are the predation rate by pests and the consumption rate of natural predators. In addition, an optimal control technique has been employed to enhance the growth of the plant population through the utilization of Pontryagin’s maximum principle. Moreover, the impact of the nine parameters on the model is examined through sensitivity analysis using the partial rank correlation coefficient method. Numerical simulations are conducted to validate the analytical findings, revealing the occurrence of bifurcation and the positive impact of control on plant population growth.

The puzzle of soil Moisture: Unravelling its dynamics in a watershed with complex physiographic features

Periodic in-situ soil moisture observations are essential for managing agriculture, water resources and validating satellite-based soil moisture products. To facilitate this, a comprehensive soil moisture monitoring network is required that provides an optimal balance between the accuracy of measurement and the associated costs. Therefore, the present study attempts to investigate the spatio-temporal variability of soil moisture over a period of 57 weeks in a watershed spanning 422 km2 with elevation ranging from 739 m to 2914 m. The watershed presents complex physiographic features such as extreme seasonal variability, differential elevations and diverse land use patterns (agricultural, forest and grasslands). The study follows a systematic sampling strategy, using a 2 km x 2 km spatial resolution across 104 grids over the entire watershed area. The soil moisture data is then used to estimate the number of optimal locations from a spatial and temporal perspective. The number of spatial optimal locations and temporal optimality are quantified using the student’s t-distribution test and the random combination method, respectively. Moreover, empirical orthogonal functions (EOFs) coupled with Spearman rank correlation method are used to evaluate the dominant physiographic factors affecting soil moisture variability within the watershed. From a comprehensive set of 71,136 field measurements, this study identified 30 optimal sampling locations necessary to capture the spatial variability of soil moisture within a ± 2 % error band. Within these 30 locations, 8 randomly selected locations can adequately represent the temporal variability of the watershed mean soil moisture within a ± 1 % error band. Furthermore, EOFs coupled with Spearman rank correlation identified elevation and sand content as the dominant physical factors influencing soil moisture variability across the watershed. The insights derived from this study provide a robust framework for carrying out soil moisture studies, especially in an ungauged watershed.

Relationship of Selected Kinematic Variables with the Performance of a Goal Kick Techniques in Football Goalkeeper

Introduction: A goal kick is awarded when the whole of the ball passes over the goal line, on the ground or in the air, having last touched a player of the attacking team, and a goal is not scored. The purpose of this study was to find out the relationship of selected angular kinematic variables with the performance of goal kick technique of soccer goalkeepers in Ethiopia's higher premier league. Method: Purposive sampling technique was used for choosing highly skilled goalkeepers. In the present study, a total of seventeen male goalkeepers (18 to 30 years of age) who had participated in the Ethiopian premier league participated. Goal kick technique was divided into three phases, such as the stance phase, the execution phase and the follow-through phase. All goalkeepers were given three trials and the best trial was used for analysis. Each participant performed three goal kicks with maximum strength that were video recorded with a camera (nikon d3200) positioned 9 m away from the place of the kick at the height of 0.95m. The silicon coachpro 7 and kinovea software were used for analyzing the data. The Joint Point Method was used in order to obtain the values of selected angular kinematic variables by developing a stick figure. The height of the Center of Gravity was calculated by segmentation method. The relationship of selected angular & linear kinematic variables with the performance of goal kick soccer goalkeeper was obtained by spearman rank correlation method. Conclusion: During stance phase, hip joint (left and right), ankle joint right, shoulder joint right and elbow joint left, do have a significant relationship with the performance of goal kick in soccer goalkeeper. At the time of execution phase, angular kinematic variables such as ankle joint left, hip joint right, shoulder joint right and elbow joint right do show a significant relationship with the performance of goal kick in soccer goalkeeper. Whereas the elbow joint left and wrist joint left were insignificant relationships. At the time of follow-through phase, ankle joint right, elbow joint left and hip joint were significant.

A Low Expression of NRF2 Enhances Oxidative Stress and Autophagy in Myofibroblasts, Promoting Progression of Chronic Obstructive Pulmonary Disease.

The inflammation phenotypes are often closely related to oxidative stress and autophagy pathway activation, which could be developed as a treatment target. The aim of this study was to explore the underlying mechanism of inflammation in chronic obstructive pulmonary disease (COPD). The lung tissue single-cell RNA-seq (scRNA-seq) dataset of GSE171541 was downloaded from the Gene Expression Omnibus (GEO) database. The marker genes were obtained from the CellMarker database. "Seurat" and "harmony" R packages were used for single-cell profiling analysis. Then, the "AUCell" R package was employed to calculate the reactive oxygen species (ROS) and autophagy pathway scores. Gene regulation network analysis was performed by applying the "SCENIC" package, followed by conducting correlation analysis with Spearman's rank correlation method. The cigarettes were used to develop a traumatic model in mice, and the expression of relevant genes was measured by qRT-PCR. The scRNA-seq analysis classified 12 cell subgroups in which the contractility of myofibroblasts was closely associated with the progression of COPD. Further analysis showed that ROS and autophagy pathways were significantly activated in myofibroblasts and that the nuclear factor erythroid 2-related factor 2 (NRF2) and its mediated oxidative stress pathway were inhibited in myofibroblasts. In addition, the downregulated NRF2 gene was negatively correlated with the expression of autophagy and ROS activation. In the traumatic mice model, NRF2 was downregulated in COPD mice but further elevated in the COPD+NRF2 mice group. Interestingly, the mRNA levels of Kelchlike ECH-associated protein 1 (Keap1), NADPH oxidase (NOX), and Cathepsin B (CTSB) were upregulated in COPD group in comparison to the control group but they were downregulated by NRF2. These results suggested that low-expressed NFR2 promoted autophagy and ROS pathway activation in myofibroblasts for COPD progression. We identified a cell myofibroblast cluster closely associated with COPD progression using the scRNA-seq analysis. The downregulated NFR2, as a key risk factor, mediated myofibroblast death by activating the oxidative stress and autophagy pathway for COPD progression.

Pathways to experienced coercion during psychiatric admission: a network analysis

BackgroundIn mental health care, experienced coercion, also known as perceived coercion, is defined as the patient’s subjective experience of being submitted to coercion. Besides formal coercion, many other factors have been identified as potentially affecting the experience of being coerced. This study aimed to explore the interplay between these factors and to provide new insights into how they lead to experienced coercion.MethodsCross-sectional network analysis was performed on data collected from 225 patients admitted to six psychiatric hospitals. Thirteen variables were selected and included in the analyses. A Gaussian Graphical Model (GGM) using Spearman’s rank-correlation method and EBICglasso regularisation was estimated. Centrality indices of strength and expected influence were computed. To evaluate the robustness of the estimated parameters, both edge-weight accuracy and centrality stability were investigated.ResultsThe estimated network was densely connected. Formal coercion was only weakly associated with both experienced coercion at admission and during hospital stay. Experienced coercion at admission was most strongly associated with the patients’ perceived level of implication in the decision-making process. Experienced humiliation and coercion during hospital stay, the most central node in the network, was found to be most strongly related to the interpersonal separation that patients perceived from staff, the level of coercion perceived upon admission and their satisfaction with the decision taken and the level of information received.ConclusionsReducing formal coercion may not be sufficient to effectively reduce patients’ feeling of being coerced. Different factors seemed indeed to come into play and affect experienced coercion at different stages of the hospitalisation process. Interventions aimed at reducing experienced coercion and its negative effects should take these stage-specific elements into account and propose tailored strategies to address them.

Global stability and optimal control of an age-structured SVEIR epidemic model with waning immunity and relapses.

The efficacy of vaccination, incomplete treatment and disease relapse are critical challenges that must be faced to prevent and control the spread of infectious diseases. Age heterogeneity is also a crucial factor for this study. In this paper, we investigate a new age-structured SVEIR epidemic model with the nonlinear incidence rate, waning immunity, incomplete treatment and relapse. Next, the asymptotic smoothness, the uniform persistence and the existence of interior global attractor of the solution semi-flow generated by the system are given. We define the basic reproduction number and prove the existence of the equilibria of the model. And we study the global asymptotic stability of the equilibria. Then the parameters of the model are estimated using tuberculosis data in China. The sensitivity analysis of is derived by the Partial Rank Correlation Coefficient method. These main theoretical results are applied to analyze and predict the trend of tuberculosis prevalence in China. Finally, the optimal control problem of the model is discussed. We choose to take strengthening treatment and controlling relapse as the control parameters. The necessary condition for optimal control is established.

The research model of forecasting agricultural carbon emissions based on ARIMA-LSTM

To accurately forecast the volume of agricultural carbon emissions in China, this paper proposes a forecasting model that combines the Autoregressive Integrated Moving Average Model (ARIMA) with Long Short-Term Memory networks (LSTM) to better handle both linear and non-linear parts in time series. Using the data on China's agricultural carbon emissions collected from 2000 to 2023 as the research subject, the data from 2000 to 2016 were first used as the training set, and the data from 2017 to 2023 were used as the test set. The Spearman's rank correlation coefficient method was utilized to study the correlation between various types of carbon emissions. Then, the established ARIMA-LSTM forecasting model was applied to predict the emissions in the test samples and make comparisons. The Absolute Relative Error (ARE) was adopted as the evaluation metric for different models, comparing the prediction errors of the ARIMA-LSTM model with those of the ARIMA and LSTM single models through analysis. The results show that the positive correlation between diesel carbon emissions and film carbon emissions was the highest; the absolute relative error of the ARIMA-LSTM model did not exceed 7%, which is significantly lower than the other two comparison models. This research model achieves high-accuracy predictions of carbon emissions, which is beneficial for the control and management of the greenhouse effect.

Stability and backward bifurcation for an HIV model with macrophages and CD4+T cells with latent reservoirs

Human immunodeficiency virus (HIV) primarily attacks CD4+ T cells but can also attack macrophage and dendritic cells leading to AIDS disease. Antiretroviral therapies are unavoidable to treat patients with HIV. However, the existing therapies failed in eliminating viral particles in infected patients. The establishment of a latency state in these patients could play a major role in this failure. To better understand the impact of different drug therapies on HIV dynamics, we propose an in-host model describing the dynamics of HIV and its interaction with both CD4+T and macrophage cells. This model incorporates the CD4+T latent reservoir as well. Results on the positivity, boundedness, and stability of solutions are shown. Furthermore, the basic reproduction number R0 is obtained using the next generation-matrix method. It is shown that the model is locally asymptotically stable at disease-free equilibrium (DFE) when the basic reproduction number R0<1. Moreover, the model exhibits either forward or backward bifurcation when R0=1. The global asymptotic stability of equilibria is investigated using suitable Lyapunov functions. To study the impact of our model parameters on the model dynamics, a sensitivity analysis is performed using the partial rank correlation coefficient method and the Latin hypercube sampling. Finally, numerical simulations are carried out to assess several drug therapy strategies to reduce HIV infection and improve health outcomes for HIV infected patients.

#2224 Higher serum level of indoxyl sulfate is not associated with increased abdominal aorta calcification in patients on maintenance hemodialysis

Abstract Background and Aims Vascular calcification is strongly associated with an increase in all-cause and cardiovascular mortality, especially in patients with and stage renal disease. Results of numerous experimental studies have shown direct toxic effect of microbial-derived uremic toxins on vascular endothelial and smooth muscle cells which may contribute vascular calcification. Meanwhile, the effects of these metabolites on vascular remodeling in patients receiving dialysis treatment remains largely unclear. Here we aimed to investigate the relationship between serum level of the uremic toxin indoxyl sulfate and severity of abdominal aorta calcification (AAC) in patients on maintenance hemodialysis. Method This single-center, cross-sectional study included eighty (40 men, average age – 59,7±11,8 years) clinically stable patients receiving hemodialysis treatment for 52(21,3-120) months. 13(16,3%) participants had history of smoking, 27(33,8%) were diabetic, 63(78,8%) had high blood pressure, 17(21,3%) – previous history of ischemic heart disease, including 5(6,3%) suffered a myocardial infarction. Severity of AAC was determined by lateral lumbar radiography with Kauppila scoring. The total AAC score ranged from 0 to 24 points, and a higher AAC score indicated a more pronounced degree of calcification. Routine laboratory data were collected before hemodialysis session after fasting for 12 hours. Serum concentration of indoxyl sulfate was assessed by ELISA using commercially available kit (Cloud-Clone Corp., USA). Statistical analysis was performed with IBM SPSS Statistics 26 program. Non-parametric Spearman's rank correlation method was used to evaluate the associations between the studied parameters. Value of p &amp;lt;0.05 was considered statistically significant in all tests. Results Median serum indoxyl sulfate was 2,1(1,4-3,0) μmol/l (the same parameter in relatively healthy individuals without impaired renal function is 0,1(0-0,3) μmol/l, р˂0,001). Serum levels of calcium (Ca) was 2,27(2,1-2,5) mmol/l, ionized calcium (Ca++) – 1,15(1,1-1,3) mmol/l, phosphate (P) – 1,6(1,3-2,0) mmol/l, intact parathyroid hormone (iPTH) – 303(162,2-492,8) pg/ml, total cholesterol (TH) – 4,5(3,5-5,4) mmol/l, low-density lipoprotein (LDL) – 2,6(2,0-3,3) mmol/l. AAC score in hemodialysis participants was 4,5(0,0-9,0) and significantly correlated with age (r=0,693; р˂0,001), Ca (r=0,208; р=0,04) and iPTH (r=0,418; р=0,021) but not with other indicators, including indoxyl sulfate concentration (r=0,164; р=0,147). Conclusion Our preliminary results do not allow to consider the elevated level of indoxyl sulfate as a factor contributing to increased AAC in patients on maintenance hemodialysis. Further prospective studies in larger populations should clarify the true role of indoxyl sulfate in vascular remodeling in individuals with chronic kidney disease.

Study on Evaluation and Prediction for Shale Gas PDC Bit in Luzhou Block Sichuan Based on BP Neural Network and Bit Structure

Deep and ultra-deep shale gas resources have great potential, but well drilling faces many challenges. The Polycrystalline Diamond Compact (PDC) bit has become the primary rock-breaking instrument for oil and gas drilling. Reasonable bit structure designs can promote rock-breaking efficiency and extend service life. In this study, reverse modeling technology is used to analyze the structural characteristics of PDC bits collected in the field, and the influence of the structural characteristics of the bit at a specific interval on the rate of penetration (ROP) and drill footage is investigated using the Spearman rank correlation coefficient method. The number of blades, cutting angle of the cutters, crown rotation radius, internal cone angle, and diameter of the cutters are discovered to be the main structural characteristics that affect the ROP and footage of the bits, and the degree of influence varies depending on the formation conditions. The number of blades, crown rotation radius, inner cone angle, and cutting angle of the cutters have a significant impact on the ROP, whereas blade thickness, gauge length, gauge width, nozzle equivalent diameter have a significant impact on the bit footage. In addition, a back propagation (BP) neural network is utilized to build a prediction model of bit footage and ROP over a certain interval based on the structural characteristics of the bit. The goodness of fit of the model is greater than 85%, and its accuracy is high. Based on the usage of the bit, the evaluation and prediction of the bit can provide a reference for the structural design and optimization of the bit in a specific interval, guide the bit selection work, rationally plan the drilling operation, and reduce the drilling cost.

Semiparametric estimation of average treatment effects in observational studies

AbstractWe propose a semiparametric method to estimate average treatment effects in observational studies based on the assumption of unconfoundedness. Assume that the propensity score model and outcome model are a general single index model, which are estimated by the kernel method and the unknown index parameter is estimated via linearized maximum rank correlation method. The proposed estimator is computationally tractable, allows for large dimension covariates and not involves the approximation of link functions. We showed that the proposed estimator is consistent and asymptotically normally distributed. In general, the proposed estimator is superior to existing methods when the model is incorrectly specified. We also provide an empirical analysis on the average treatment effect and average treatment effect on the treated of 401(k) eligibility on net financial assets.

Role of Sedentary Behavior as a Risk Factor for Hypertension and Obesity

Previous studies have shown that sedentary activity is closely related to an increased risk of hypertension and obesity. However, to understand the relationship between sedentary activity, hypertension, and obesity more deeply, this study involves further analysis. This study aimed to evaluate the relationship between sedentary activity and the risk of hypertension and obesity. This research is a quantitative study using an observational design, through a prospective cohort approach. Sedentary activity was measured using the Adolescent Sedentary Activity Questionnaire (ASAQ). The correlation between sedentary activity and the risk of hypertension and obesity was analyzed using the Spearman Rank correlation method. Sedentary activity becomes a risk factor for hypertension and obesity with a moderate correlation level (r=0.416). High levels of sedentary activity significantly increase the risk of hypertension. This study confirms the significant relationship between sedentary activity and the risk of hypertension and obesity. High levels of sedentary activity increase the risk of hypertension significantly. Therefore, it is recommended to encourage an active lifestyle and reduce sedentary activity to prevent hypertension and obesity.

Parameter estimation and global sensitivity analysis of a bacterial-plasmid model with impulsive drug treatment

In this paper, a mathematical model is developed to study bacterial resistance caused by plasmids and mutations in the presence of the impulsive drug treatment. Firstly, the stability of the bacterial-plasmid extinction periodic solution is proved by Floquet theory and the permanence of system is presented while some conditions are satisfied. Secondly, the nontrivial periodic solution bifurcated from the bacterial-plasmid extinction periodic solution is obtained in view of the four-dimensional impulsive control of bifurcation method. Good fitting results are given by the Mean Absolute Percentage Error method for four different cases of bacterial media. Further, the global sensitivity of R0 is analyzed by the Partial Rank Correlation Coefficient method, and the parameters that have important influence on the system are determined. Finally, numerical simulations are performed to validate the accuracy of the theoretical findings.

The Relation Between Fisheries Counseling Capacity and Fisherman Satisfaction in Counseling Activities in Batang Gasan, Padang Pariaman Regency, West Sumatera Province

Batang Gasan District, Padang Pariaman Regency, West Sumatra Province has a fisheries product processing segment, both in terms of human resources (interest and experience) and natural resources (fisheries production). The purpose of this study was to determine the capacity for counseling for fisheries workers, fishermen’s satisfaction, and the relationship between the capacity of fisheries counseling workers and fishermen satisfaction in counseling related activities. Respondents in this study were fishermen who participated in counseling activities, as many as 68 people were used as samples using accidental sampling. The data analysis technique uses the Spearman Rank correlation method (Rs). In which, the results of this study are the capacity of counseling workers as facilitators is considered good, the capacity of counseling workers as motivators and educators is considered not good and the capacity of counseling workers as communicators is considered quite good, fishermen's satisfaction with planning is considered as quite satisfied, fishermen's satisfaction with implementation and evaluation is considered as not satisfied, and the capacity of counseling workers as facilitators, motivators, educators and communicators is significantly related to fishermen's satisfaction. It is expected that the capacity of counseling workers as motivators and educators is further enhanced in counseling activities so that fishermen feel satisfaction and can make fishermen's behavior change.

Mathematical modeling of endogenous and exogenously administered T cell recirculation in mouse and its application to pharmacokinetic studies of cell therapies

IntroductionIn vivo T cell migration has been of interest to scientists for the past 60 years. T cell kinetics are important in the understanding of the immune response to infectious agents. More recently, adoptive T cell therapies have proven to be a most promising approach to treating a wide range of diseases, including autoimmune and cancer diseases, whereby the characterization of cellular kinetics represents an important step towards the prediction of therapeutic efficacy. MethodsHere, we developed a physiologically-based pharmacokinetic (PBPK) model that describes endogenous T cell homeostasis and the kinetics of exogenously administered T cells in mouse. Parameter calibration was performed using a nonlinear fixed-effects modeling approach based on published data on T cell kinetics and steady-state levels in different tissues of mice. The Partial Rank Correlation Coefficient (PRCC) method was used to perform a global sensitivity assessment. To estimate the impact of kinetic parameters on exogenously administered T cell dynamics, a local sensitivity analysis was conducted. ResultsWe simulated the model to analyze cellular kinetics following various T cell doses and frequencies of CCR7+ T cells in the population of infused lymphocytes. The model predicted the effects of T cell numbers and of population composition of infused T cells on the resultant concentration of T cells in various organs. For example, a higher percentage of CCR7+ T cells among exogenously administered T lymphocytes led to an augmented accumulation of T cells in the spleen. The model predicted a linear dependence of T cell dynamics on the dose of adoptively transferred T cells. DiscussionThe mathematical model of T cell migration presented here can be integrated into a multi-scale model of the immune system and be used in a preclinical setting for predicting the distribution of genetically modified T lymphocytes in various organs, following adoptive T cell therapies.

Early Childhood Caries and Its Association With Behavior in Preschool Children.

Background and aim Early childhood caries (ECC) is a profoundly impactful multifactorial condition that not only influences a child's overall well-being but also diminishes their quality of life. Given the limited availability of literature on the relationship between children's behavior and ECC, the present study utilized a standardized assessment tool to assess the association between ECC and behavioral changes in preschool children. Methodology Our study cohort consisted of 120 healthy preschool children, aged 18-60 months, evenly divided into two groups: caries-free (group I) and caries active (group II). Clinical features of ECC were meticulously inspected in each child, and the parents or caregivers completed the Child Behavior Checklist (CBCL), which comprises 100 questions related to a child's daily behavior. The total scores, the narrow-band subscales, and raw scores were obtained. Accordingly, for each raw score, t-scores were obtained using the graphic display. These scores were then subjected to various statistical analyses including the Kolmogorov-Smirnov test, Mann-Whitney U test, and Spearman's rank correlation method. Results Results of the present study revealed that there were no significant differences in behavior based on demographic factors such as gender and age. However notable differences were observed in several aspects of behavior between the two groups. Conclusion Caries-active children exhibited significantly higher levels of behavioral problems compared to their caries-free counterparts.

Assessing the impact of information-induced self-protection on Zika transmission: A mathematical modeling approach

Abstract As per the World Health Organization’s (WHO’s) suggestions, personal protection via adopting precautionary measures is one of the most effective control aspects to avoid Zika infection in the absence of suitable medical treatment. This personal protection further can be enhanced and explored by propagating information about disease prevalence. Therefore, in this study, we wish to see the effect of information on Zika transmission by formulating a compartmental mathematical model that quantifies the effect of an individual’s behavioral response as self-protection due to information. Furthermore, the basic reproduction number was calculated using the next-generation matrix technique. The model analysis was carried out to determine the local and global stability properties of equilibrium points. In addition, the model shows the occurrence of forward bifurcation when the reproduction number crosses unity. To understand the impact of various model parameters, we conducted a sensitivity analysis using both the normalized sensitivity index and the partial rank correlation coefficient methods. Moreover, we performed numerical simulations to assess the influence of important parameters on the model’s behavior for Zika prevalence. Our study accentuates that as information-induced self-protection increases, the prevalence of Zika infection will be at a very minimum level, and this observation is in line with WHO suggestions.

Adaptive thermal error prediction for CNC machine tool spindle using online measurement and an improved recursive least square algorithm

Establishing models for predicting and compensating for spindle thermal errors is cost-effective and necessary to improve the accuracy of machine tools for smart manufacturing. However, the prediction performance of existing methods deteriorates significantly with dynamic working conditions of machine tools because training from static conditions leads to the inability to adapt to dynamic conditions. Therefore, an adaptive thermal error modeling method using online measurement and an improved recursive least square algorithm is proposed to fill this research gap, which updates the thermal error model adaptively to ensure that dynamic working conditions are learned in real time. Particularly, Spearman's rank correlation coefficient method is first adopted for temperature-sensitive point selection to capture the nonlinear relationship between temperature and thermal error variables. Furthermore, a variable-forgetting factor-based recursive least square (VFF-RLS) algorithm is proposed to improve the prediction performance, in which the proposed variable forgetting factor is adaptively updated according to real-time thermal error data collected by online measurement. The experimental results showed that the proposed VFF-RLS method can maintain a high prediction accuracy of 1.75 μm and robustness of 0.16 μm on both constant and dynamic working conditions. The effectiveness of the VFF-RLS method is validated by verification experiments.

Влияние заболеваемости женщин в период беременности, родов и послеродовой период на показатели использования коечного фонда отделений патологии беременности.

P u r p o s e : assessment of the impact of morbidity in women during pregnancy, childbirth and the postpartum period on the utilization of bed capacity in pregnancy pathology departments. Materials and methods. Based on official statistics, a comparative statistical analysis of the incidence rates of women of fertile age with the XV class of diseases ICD‑10 «Pregnancy, childbirth and the postpartum period» and indicators of the use of bed capacity in pregnancy pathology departments of St. Petersburg with indicators for the Russian Federation and the Northwestern Federal District in dynamics for 2017 was carried out. 2022. To assess the relationship between indicators, the nonparametric Spearman rank correlation method was used. Statistical data processing was carried out using the MS Office‑2016 and StatSoft-Statistica 10.0 software packages. Results. In 2017–2022, there were significant differences in the level and dynamics of the incidence of class XV diseases in women of fertile age in the metropolis and from the indicators for the Russian Federation and the Northwestern Federal District. With multidirectional dynamics of these indicators, almost the entire study period, the incidence rate of women in St. Petersburg was lower than the national and district averages, and over six years the incidence rate decreased by 30.8%. The work of pregnancy pathology beds, the average length of stay of patients on them in the metropolis were higher than the Russian and regional averages, and the turnover of beds was higher. It was revealed that in Russia and the Northwestern Federal District, the morbidity of pregnant women, women in labor and postpartum had virtually no effect on the average occupancy of a pregnancy pathology bed per year and its average downtime, and in the metropolis, with a decrease in morbidity rates, bed occupancy moderately decreased and its downtime increased. At the same time, the impact of the incidence of class XV diseases in women on the average length of stay of patients in pregnancy pathology beds in the country as a whole and in the Northwestern Federal District was more significant than in the metropolis. At the same time, the impact of morbidity among pregnant women, women in labor and postpartum in the city on the turnover of beds in this profile was less significant than on the indicators in the federal district. It was found that the decrease in morbidity had a moderately pronounced effect on reducing the length of stay of women in the city’s pregnancy pathology departments and increasing the turnover of beds. Conclusion. There are differences in the level and dynamics of morbidity indicators for pregnant women, parturients and postpartum women and indicators of the use of obstetric beds for the pathology of pregnancy in the metropolis from these indicators in Russia and the Northwestern Federal District. The incidence of women during this period has a moderate impact on the average bed occupancy per year, the average length of stay on a bed, bed turnover and the average bed idle time. The impact of a decrease in morbidity on the use of pregnancy pathology beds in the metropolis differed from Russia and the Northwestern Federal District, which was expressed in the strength and significance of the connection.