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Regression analysis of squeezing-induced hybrid nanofluid flow in Darcy-Forchheimer porous medium
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作者 K.MUHAMMAD M.SARFRAZ 《Applied Mathematics and Mechanics(English Edition)》 2025年第1期193-208,共16页
This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates.One plate remains stationary,while the other moves downward at a squeezing veloci... This article presents a mathematical model addressing a scenario involving a hybrid nanofluid flow between two infinite parallel plates.One plate remains stationary,while the other moves downward at a squeezing velocity.The space between these plates contains a Darcy-Forchheimer porous medium.A mixture of water-based fluid with gold(Au)and silicon dioxide(Si O2)nanoparticles is formulated.In contrast to the conventional Fourier's heat flux equation,this study employs the Cattaneo-Christov heat flux equation.A uniform magnetic field is applied perpendicular to the flow direction,invoking magnetohydrodynamic(MHD)effects.Further,the model accounts for Joule heating,which is the heat generated when an electric current passes through the fluid.The problem is solved via NDSolve in MATHEMATICA.Numerical and statistical analyses are conducted to provide insights into the behavior of the nanomaterials between the parallel plates with respect to the flow,energy transport,and skin friction.The findings of this study have potential applications in enhancing cooling systems and optimizing thermal management strategies.It is observed that the squeezing motion generates additional pressure gradients within the fluid,which enhances the flow rate but reduces the frictional drag.Consequently,the fluid is pushed more vigorously between the plates,increasing the flow velocity.As the fluid experiences higher flow rates due to the increased squeezing effect,it spends less time in the region between the plates.The thermal relaxation,however,abruptly changes the temperature,leading to a decrease in the temperature fluctuations. 展开更多
关键词 convective boundary condition Darcy-Forchheimer medium hybrid nanofuid Joule heating magnetohydrodynamic(MHD) numerical solution squeezing flow regression analysis
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The Efficacy of Statistics in All Major Fields of Research: A Focus on Regression Analysis
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作者 Joseph Ozigis Akomodi 《Open Journal of Statistics》 2025年第1期53-72,共20页
The abstract provided offers a succinct overview of the research paper’s focus on the significance of statistics, specifically regression analysis, across diverse fields. The emphasis on regression analysis indicates... The abstract provided offers a succinct overview of the research paper’s focus on the significance of statistics, specifically regression analysis, across diverse fields. The emphasis on regression analysis indicates its importance as a statistical method that helps researchers understand relationships between variables and make predictions based on data. The inclusion of multiple disciplines, such as health sciences, social sciences, environmental studies, economics, engineering, clinical psychology, social psychology, developmental psychology, cognitive psychology, and education highlights the interdisciplinary relevance of regression analysis. This breadth suggests that the findings and methodologies discussed in the paper may have wide applications, benefiting various sectors by enhancing the quality of research outcomes. The mention of “methodologies and data analysis techniques” indicates that the paper will likely delve into specific statistical approaches, offering a comprehensive examination of how regression analysis is applied in real-world scenarios. This nuance is essential, as it demonstrates the research’s commitment to not only presenting theoretical insights but also practical applications. Furthermore, the abstract states that regression analysis “enhances the validity of findings” and “informs data-driven decision-making.” This assertion underlines the critical role that robust statistical methods play in ensuring that research conclusions are reliable and applicable. The ability of regression analysis to provide clarity and support informed decisions makes it a valuable tool in both academic and professional settings. The abstract effectively outlines the paper’s exploration of regression analysis in various fields, underscoring its importance in enhancing research validity and facilitating informed decision-making. The interdisciplinary nature of the research broadens its appeal and emphasizes the need for rigorous statistical approaches in addressing complex issues across different domains. 展开更多
关键词 Statistics through the Less of Regression analysis in All Fields of Study
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Regression analysis and its application to oil and gas exploration:A case study of hydrocarbon loss recovery and porosity prediction,China
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作者 Yang Li Xiaoguang Li +3 位作者 Mingyu Guo Chang Chen Pengbo Ni Zijian Huang 《Energy Geoscience》 EI 2024年第4期240-252,共13页
In oil and gas exploration,elucidating the complex interdependencies among geological variables is paramount.Our study introduces the application of sophisticated regression analysis method at the forefront,aiming not... In oil and gas exploration,elucidating the complex interdependencies among geological variables is paramount.Our study introduces the application of sophisticated regression analysis method at the forefront,aiming not just at predicting geophysical logging curve values but also innovatively mitigate hydrocarbon depletion observed in geochemical logging.Through a rigorous assessment,we explore the efficacy of eight regression models,bifurcated into linear and nonlinear groups,to accommodate the multifaceted nature of geological datasets.Our linear model suite encompasses the Standard Equation,Ridge Regression,Least Absolute Shrinkage and Selection Operator,and Elastic Net,each presenting distinct advantages.The Standard Equation serves as a foundational benchmark,whereas Ridge Regression implements penalty terms to counteract overfitting,thus bolstering model robustness in the presence of multicollinearity.The Least Absolute Shrinkage and Selection Operator for variable selection functions to streamline models,enhancing their interpretability,while Elastic Net amalgamates the merits of Ridge Regression and Least Absolute Shrinkage and Selection Operator,offering a harmonized solution to model complexity and comprehensibility.On the nonlinear front,Gradient Descent,Kernel Ridge Regression,Support Vector Regression,and Piecewise Function-Fitting methods introduce innovative approaches.Gradient Descent assures computational efficiency in optimizing solutions,Kernel Ridge Regression leverages the kernel trick to navigate nonlinear patterns,and Support Vector Regression is proficient in forecasting extremities,pivotal for exploration risk assessment.The Piecewise Function-Fitting approach,tailored for geological data,facilitates adaptable modeling of variable interrelations,accommodating abrupt data trend shifts.Our analysis identifies Ridge Regression,particularly when augmented by Piecewise Function-Fitting,as superior in recouping hydrocarbon losses,and underscoring its utility in resource quantification refinement.Meanwhile,Kernel Ridge Regression emerges as a noteworthy strategy in ameliorating porosity-logging curve prediction for well A,evidencing its aptness for intricate geological structures.This research attests to the scientific ascendancy and broad-spectrum relevance of these regression techniques over conventional methods while heralding new horizons for their deployment in the oil and gas sector.The insights garnered from these advanced modeling strategies are set to transform geological and engineering practices in hydrocarbon prediction,evaluation,and recovery. 展开更多
关键词 Regression analysis Oil and gas exploration Multiple linear regression model Nonlinear regression model Hydrocarbon loss recovery Porosity prediction
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Analysis of anxiety and depression status and their influencing factors in patients with diabetic retinopathy
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作者 Sheng Gao Xia Liu 《World Journal of Psychiatry》 SCIE 2024年第12期1905-1917,共13页
BACKGROUND Diabetic retinopathy(DR)is a common complication of diabetes and the leading cause of visual impairment and blindness.It has a serious impact on the mental and physical health of patients.AIM To evaluate th... BACKGROUND Diabetic retinopathy(DR)is a common complication of diabetes and the leading cause of visual impairment and blindness.It has a serious impact on the mental and physical health of patients.AIM To evaluate the anxiety and depression status of patients with DR,we examined their influencing factors.METHODS Two hundred patients with DR admitted to the outpatient and inpatient departments of ophthalmology and endocrinology at our hospital were selected.A questionnaire was conducted to collect general patient information.Depression and anxiety were assessed using the Patient Health Questionnaire-9 and Sevenitem Generalized Anxiety Disorder scale,respectively.The diabetes specific quality of life scale and Social Support Rating Scale were used to assess the quality of life of patients with DR and their social support,respectively.Logistic regression analysis was used to assess the correlations.RESULTS The prevalence of depression and anxiety were 26%(52/200)and 14%(28/200),respectively.Regression analysis revealed that social support was associated with depression[odds ratio(OR)=0.912,95%confidence interval(CI):0.893-0.985]and anxiety(OR=0.863,95%CI:0.672-0.994).Good quality of life(diabetes specific quality of life scale score<40)was a protective factor against anxiety(OR=0.738,95%CI:0.567-0.936)and depression(OR=0.573,95%CI:0.4566-0.784).Visual impairment significantly increased the likelihood of depression(OR=1.198,95%CI:1.143-1.324)and anxiety(OR=1.746,95%CI:1.282-2.359).Additionally,prolonged diabetes duration and history of hypertension were significant risk factors for both conditions,along with a family history of diabetes.CONCLUSION Key factors influencing anxiety and depression in patients with DR include social support,quality of life,visual impairment,duration of diabetes,family history of diabetes,and history of hypertension. 展开更多
关键词 Diabetic retinopathy DEPRESSION ANXIETY Influencing factors Regression analysis
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Logistic Regression Analysis of Catheter Fixation Defects and Their Influencing Factors
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作者 Xiaoli LI 《Medicinal Plant》 2024年第6期63-65,共3页
[Objectives] To analyze the influencing factors of fixed defects in patients with catheter fixation in clinical nursing work, in order to provide the best catheter fixation nursing plan for patients.[Methods] 176 inpa... [Objectives] To analyze the influencing factors of fixed defects in patients with catheter fixation in clinical nursing work, in order to provide the best catheter fixation nursing plan for patients.[Methods] 176 inpatients with indwelling catheter from surgical system of Taihe Hospital in Shiyan City from August 2022 to March 2023 were selected. Using a retrospective analysis method, the influencing factors of catheter fixation defects in the study subjects were divided into two categories based on objective characteristics: type I non modifiable influencing factors and type II modifiable influencing factors. Using the standard for catheter fixation defects, whether the patient had catheter fixation defects was determined. After classified and statistically analyzed item by item, binary Logistic multiple regression analysis was used to identify the influencing factors.[Results] The occurrence of catheter fixation defects in patients with catheter fixation was related to factors such as whether the patient was evaluated before fixation, whether the fixation method was standardized and systematic, whether there was sufficient communication between nurses and patients, and the patient s knowledge of catheter fixation. It was also influenced by factors such as the patient s age, catheterization site, catheterization number, catheterization duration, where there was a consciousness disorder, educational level, and external environmental temperature.[Conclusions] Early attention to the key factors affecting patients with catheter fixation defects can effectively prevent adverse factors and provide patients with the best catheter fixation nursing plan to improve nursing quality. 展开更多
关键词 CATHETER Fixed defect Influence factor Logistic regression analysis
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Change Point Analysis to Detect the Effect of Pruning Severity on Tree Growth
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作者 Yutaka Iguchi 《Open Journal of Forestry》 2024年第1期67-73,共7页
The effect of pruning severity on tree growth was analyzed by change point detection using segmented regression. The present study applied this analysis to a well-known published data set including diameter growth res... The effect of pruning severity on tree growth was analyzed by change point detection using segmented regression. The present study applied this analysis to a well-known published data set including diameter growth response, tree age, pruning severity and pretreatment crown size. First, multiple regression analysis was performed to assess the effect of tree age, pruning severity and pretreatment crown size on diameter growth response. Next, segmented regression analysis was performed to assess the effect of pruning severity on diameter growth response. The results of the multiple regression showed that diameter growth response was significantly influenced by pruning severity and pretreatment crown size. The results of the segmented regression showed that in the whole data set, an abrupt change toward a decrease in diameter growth response was detected at 25% of the live crown removed. However, in the group of fully crowned and open-grown, diameter growth response continuously decreased with increasing pruning severity with no significant abrupt change, whereas in the group of 70% - 90% live crown, diameter growth response did not significantly decrease up to the break point (53% crown removed) and then abruptly decreased. This may be the first study to show the numerical evaluation of the effect of pruning severity on tree growth by change point analysis. 展开更多
关键词 Regression analysis Crown Removal Limit Tree Growth PRETREATMENT Abrupt Change
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Analysis and Evaluation of Housing Price Factors Using Mathematical Modeling
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作者 Xing Lyu 《Proceedings of Business and Economic Studies》 2024年第6期17-23,共7页
In recent years,the real estate industry has achieved significant progress,driving the development of related sectors and playing a crucial role in economic growth.However,rapid real estate market expansion has led to... In recent years,the real estate industry has achieved significant progress,driving the development of related sectors and playing a crucial role in economic growth.However,rapid real estate market expansion has led to challenges,particularly concerning housing prices,which have drawn widespread societal attention.This article explores the theories of housing prices,analyzes factors influencing them,and conducts an empirical investigation of the impact of representative factors on ordinary residential prices.Using regression analysis and the entropy weight method,a mathematical model was developed to examine how various factors affect housing prices. 展开更多
关键词 Mathematical modeling Regression analysis Housing price Formation factors Multiple linear regression H ypothesis testing Multiple decision coefficients
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Analysis and Evaluation Indicator Selection of Chilling Tolerance of Different Cotton Genotypes 被引量:2
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作者 武辉 侯丽丽 +4 位作者 周艳飞 范志超 石俊毅 阿丽艳.肉孜 张巨松 《Agricultural Science & Technology》 CAS 2012年第11期2338-2346,共9页
[Objectivc] This study aimed to investigate the chilling tolerance of seedlings of different cotton genotypes and screen appropriate indicators for assess- ing chilling tolerance, to establish reliable mathematical ev... [Objectivc] This study aimed to investigate the chilling tolerance of seedlings of different cotton genotypes and screen appropriate indicators for assess- ing chilling tolerance, to establish reliable mathematical evaluation model for chilling tolerance of cotton, thus providing theoretical basis for breeding and promoting new chilling-tolerant cotton germplasms and large-scale evaluation of chilling tolerance of cotton varieties. [Method] Fifteen cotton varieties (lines) were used as experimental materials. The photosynthetic gas exchange parameters, chlorophyll fluorescence ki- netic parameters, chlorophyll content, relative soluble sugar content, malonaldehyde content, relative proiine content, relative conductivity and other 12 physiological indi- cators of seedling leaves under low temperature treatment (5 ℃, 12 h) and recovery treatment (25 ℃. 24 h) were determined; based on the chilling tolerance coefficient (CTC) of various individual indicators, the comprehensive evaluation of chilling toler- ance was conducled by using principal component analysis, hierarchical cluster anal- ysis and stepwise regression analysis. [Result] The results showed that the 12 indi- vidual physiological indicators could be classified into 7 independent comprehensive components by principal component analysis; 15 cotton varieties (lines) were clus- tered into three categories by using membership function method and hierarchical cluster analysis; the mathematical model for evaluating chilling tolerance of cotton seedlings was established: D =0.275 -0.244Fo1 +0.206Fv/Fm1+0.326g,%-0.056SS + 0.225MDA+O.O38REC (FF=0.995), and the evaluation accuracy of the equation was higher than 94.25%,0. Six identification indicators closely related to chilling tolerance were screened, including Fo,, Fv/Fm1, Seedling leaves of cotton varieties (lines) gs2, SS, MDA, and REC. [Conclusion] with high chilling tolerance are less dam- aged under low temperature stress, and are able to maintain relatively high photo- synthetic electron transport capacity and high stomatal conductance after recovery treatment, which is contributed to gas exchange and recovery of photosynthetic ca- pacity. Determination of the six indicators under the same stress condition can be adopted for rapid identification and prediction of the chilling tolerance of other cotton varieties, which provides basis for the breeding, promotion, identification and screen- ing of chilling tolerant germplasms. 展开更多
关键词 COTTON Chilling tolerance Principal components analysis Comprehensiveevaluation Stepwise regression analysis
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Material Design and Experimental Analysis of a New Type of Semiconductor ER Fluids
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作者 朱石沙 魏宸官 《Journal of Beijing Institute of Technology》 EI CAS 2000年第2期155-159,共5页
To improve the electrorheological effect of electrorheological fluid (ERF), a new type of the electrosensitive particle material, polynaphthalene quinone was prepared, whose molecules contain blended atoms of nitrogen... To improve the electrorheological effect of electrorheological fluid (ERF), a new type of the electrosensitive particle material, polynaphthalene quinone was prepared, whose molecules contain blended atoms of nitrogen, oxygen, sulphur and big π bond conjugate system. In both DC and AC electric fields, the ERF material showed a distinct ER effect. Especially, in the alternating electric field, the shear stress of this material versus AC voltage has a better quadratic relation than that of the other materials. The experimental data showed that organic semiconductor polymers with big π bond conjugate system are a new type of electrosensitive particle materials which are worth well developing. 展开更多
关键词 electrorheological fluid(ERF) alternating electric field regression analysis
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Population Quantity Variations of Oriental Fruit Fly (Bactrocera dorsalis Hendel) on the Basis of Stepwise Regression Analysis
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作者 张丽莲 杨林楠 杨仕生 《Plant Diseases and Pests》 CAS 2010年第2期32-34,共3页
[Objective] The research aimed to study the significant influence factors of the population variations of oriental fruit fly. [Method] Using stepwise regression analysis, the population variations law of oriental frui... [Objective] The research aimed to study the significant influence factors of the population variations of oriental fruit fly. [Method] Using stepwise regression analysis, the population variations law of oriental fruit fly in Jianshui County of Yunnan province and the meteorological factors that caused its occurrence were analyzed. And the regression model was built. Finally, the regression model was tested on the basis of the data in Jianshui County of Yunnan Province during 2004-2006.[Result] The main meteorological factors that influenced the occurrence of oriental fruit fly were relative humidity, the lowest monthly temperature and rainfall. [Conclusion] This study will provide certain reference for the prediction researches on the time, quantity and occurrence peak of oriental fruit fly. 展开更多
关键词 Oriental fruit fly Stepwise regression analysis Meteorological factors
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Empirical analysis on risk of security investment
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作者 AN Peng LI Sheng-hong 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2009年第2期127-134,共8页
The paper analyzes the theory and application of Markowitz Mean-Variance Model and CAPM model. Firstly, it explains the development process and standpoints of two models and deduces the whole process in detail. Then 3... The paper analyzes the theory and application of Markowitz Mean-Variance Model and CAPM model. Firstly, it explains the development process and standpoints of two models and deduces the whole process in detail. Then 30 stocks are choosen from Shangzheng 50 stocks and are testified whether the prices of Shanghai stocks conform to the two models. With the technique of time series and panel data analysis, the research on the stock risk and effective portfolio by ORIGIN and MATLAB software is conducted. The result shows that Shanghai stock market conforms to Markowitz Mean-Variance Model to a certain extent and can give investors reliable suggestion to gain higher return, but there is no positive relation between system risk and profit ratio and CAPM doesn't function well in China's security market. 展开更多
关键词 Markowitz Mean-Variance Model Capital Asset Pricing Model time series analysis regressive analysis securities market
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Impact of Linggui Zhugan decoction on microwave ablation outcomes and recurrence in liver cancer
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作者 Rui Huang Jing Cui 《World Journal of Gastrointestinal Oncology》 2025年第2期105-118,共14页
BACKGROUND Liver cancer is one of the most common malignant tumors of the digestive system,and early detection and effective treatment are crucial for improving the prognosis.Microwave ablation(MWA)has shown promising... BACKGROUND Liver cancer is one of the most common malignant tumors of the digestive system,and early detection and effective treatment are crucial for improving the prognosis.Microwave ablation(MWA)has shown promising results as a local therapeutic method for liver cancer;however,further improvement of its efficacy remains a key focus of current research.AIM To evaluate the clinical efficacy of Linggui Zhugan decoction combined with MWA for the treatment of primary liver cancer.METHODS Data were collected from 164 patients with primary liver cancer who underwent MWA at our hospital between March 2019 and April 2021.Among them,79 patients(control group)received routine treatments and 85 patients(research group)received Linggui Zhugan decoction in addition to routine treatment.The clinical efficacy,incidence of adverse reactions,and levels of serum alphafetoprotein(AFP),des-γ-carboxy prothrombin(DCP),AFP-L3,total bilirubin(TBil),alanine aminotransferase(ALT),CD4 cell count,CD8 cell count,and CD4/CD8 ratio were compared between the two groups,before and after treatment.The three-year recurrence rates between the two groups were compared,and independent prognostic factors for recurrence were identified.RESULTS The study results revealed that the objective response rate(ORR)in the research group was significantly higher than that in the control group(P=0.005).After treatment,the CD4 cell count and CD4/CD8 ratio significantly increased,whereas the CD8 cell count and TBil,ALT,AFP,DCP,and AFP-L3 Levels were significantly lower in the research group than in the control group(P<0.001).The Cox regression analysis revealed that the treatment regimen(P=0.003),presence of cirrhosis(P=0.019),tumor diameter(P=0.037),Child-Pugh score(P=0.003),pretreatment AFP level(P=0.006),and AFP-L3 Level(P=0.002)were independent prognostic factors for disease-free survival.CONCLUSION The combination of Linggui Zhugan decoction with MWA significantly improved the clinical efficacy and longterm prognosis of patients with primary liver cancer. 展开更多
关键词 Primary liver cancer Microwave ablation Linggui Zhugan decoction Clinical efficacy Disease-free survival Cox regression analysis
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Agricultural Input and Output in Jiangsu Province with Case Analysis
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作者 杜华章 《Agricultural Science & Technology》 CAS 2014年第11期2006-2010,2025,共6页
[Objective] The aim was to explore interrelationship between agricultural input and output in Jiangsu and the influence degrees of input factors on agricultur-al output. [Method] Quantitative analysis and evaluation w... [Objective] The aim was to explore interrelationship between agricultural input and output in Jiangsu and the influence degrees of input factors on agricultur-al output. [Method] Quantitative analysis and evaluation were made on agricultural input and output in Jiangsu during 1990-2012 as per factor analysis and regression analysis. [Result] The result of factor analysis showed that since the 1990s, the comprehensive efficiency of agricultural input/output in Jiangsu was growing and in-put/output of agriculture, forestry, animal husbandry and fishery, crop farming, and of food production were extracted, whose scores reflect the changes of input/output ef-ficiencies in terms of agriculture, forestry, animal husbandry, fishery, crop farming and food production in the two decades. The results of regression analysis indicated that the effects of the three indices on agricultural output tended to be volatile and the influence degrees were concluded also by regression parameters. [Conclusion] The research provides theoretical references for agricultural input/output structure in Jiangsu Province. 展开更多
关键词 Agriculture Input/output Factor analysis Regression analysis Jiangsu Province
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Risk factor analysis of post-ERCP cholangitis: A single-center experience 被引量:15
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作者 Min Chen Lei Wang +5 位作者 Yun Wang Wei Wei Yu-Ling Yao Ting-Sheng Ling Yong-Hua Shen Xiao-Ping Zou 《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS CSCD 2018年第1期55-58,共4页
Background: Endoscopic retrograde cholangiopancreatography(ERCP) may have complications. Our study aimed to investigate the risk factors and prevention of post-ERCP cholangitis.Methods: We retrospectively analyzed 423... Background: Endoscopic retrograde cholangiopancreatography(ERCP) may have complications. Our study aimed to investigate the risk factors and prevention of post-ERCP cholangitis.Methods: We retrospectively analyzed 4234 cases undergone ERCP in the Affiliated Drum Tower Hospital of Nanjing University Medical School from January 2008 to December 2013. Patient-related factors and procedure-related factors were analyzed to find the risk factors of post-ERCP cholangitis. The time point of post-ERCP cholangitis was also analyzed. Univariate and multivariate analyses were performed to define the independent risk factors of post-ERCP cholangitis.Results: The success rate of ERCP was 96.8%(4099/4234). The overall complication rate was 9.4%(399/4234). Post-ERCP cholangitis occurred in 102 cases(2.4%, 102/4234). The most dangerous time of post-ERCP cholangitis was from 24 h–48 h after ERCP(45.1%, 46/102). Univariate analysis revealed that age, hypertension, diabetes, previous ERCP history, biliary stent insertion, pancreatography, endoscopic sphincterotomy, balloon dilation and hilar obstruction were risk factors of post-ERCP cholangitis(P < 0.05). Multivariate analysis indicated that age, previous ERCP history and hilar obstruction were independent risk factors(P < 0.05). While endoscopic stone extraction was the potential protective factor.Conclusions: Many risk factors are involved in post-ERCP cholangitis. Among them, old age, previous ERCP history and hilar obstruction were independently related to this post-ERCP complication. 展开更多
关键词 CHOLANGITIS Endoscopic retrograde CHOLANGIOPANCREATOGRAPHY Risk factors Logistic regression analysis
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DDM regression analysis of the in-situ stress field in a non-linear fault zone 被引量:9
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作者 Ke Li Ying-yi Wang Xing-chun Huang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第7期567-573,共7页
A multivariable regression analysis of the in-situ stress field, which considers the non-linear deformation behavior of faults in practical projects, is presented based on a newly developed three-dimensional displacem... A multivariable regression analysis of the in-situ stress field, which considers the non-linear deformation behavior of faults in practical projects, is presented based on a newly developed three-dimensional displacement discontinuity method (DDM) program. The Bar- ton-Bandis model and the Kulhaway model are adopted as the normal and the tangential deformation model of faults, respectively, where the Mohr-Coulomb failure criterion is satisfied. In practical projects, the values of the mechanical parameters of rock and faults are restricted in a bounded range for in-situ test, and the optimal mechanical parameters are obtained from this range by a loop. Comparing with the traditional finite element method (FEM), the DDM regression results are more accurate. 展开更多
关键词 displacement discontinuity method (DDM) in-situ stress regression analysis FAULTS ROCK
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Impacts of COVID-19 pandemic on urban park visitation:a global analysis 被引量:6
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作者 Dehui(Christina)Geng John Innes +1 位作者 Wanli Wu Guangyu Wang 《Journal of Forestry Research》 SCIE CAS CSCD 2021年第2期553-567,共15页
The COVID-19 pandemic has resulted in over 33 million confirmed cases and over 1 million deaths globally,as of 1 October 2020.During the lockdown and restrictions placed on public activities and gatherings,green space... The COVID-19 pandemic has resulted in over 33 million confirmed cases and over 1 million deaths globally,as of 1 October 2020.During the lockdown and restrictions placed on public activities and gatherings,green spaces have become one of the only sources of resilience amidst the coronavirus pandemic,in part because of their positive effects on psychological,physical and social cohesion and spiritual wellness.This study analyzes the impacts of COVID-19 and government response policies to the pandemic on park visitation at global,regional and national levels and assesses the importance of parks during this global pandemic.The data we collected primarily from Google’s Community Mobility Reports and the Oxford Coronavirus Government Response Tracker.The results for most countries included in the analysis show that park visitation has increased since February 16th,2020 compared to visitor numbers prior to the COVID-19 pandemic.Restrictions on social gathering,movement,and the closure of workplace and indoor recreational places,are correlated with more visits to parks.Stay-at-home restrictions and government stringency index are negatively associated with park visits at a global scale.Demand from residents for parks and outdoor green spaces has increased since the outbreak began,and highlights the important role and benefits provided by parks,especially urban and community parks,under the COVID-19 pandemic.We provide recommendations for park managers and other decision-makers in terms of park management and planning during health crises,as well as for park design and development.In particular,parks could be utilized during pandemics to increase the physical and mental health and social well-being of individuals. 展开更多
关键词 COVID-19 COVID-19 response policies Parks visitation Stepwise regression analysis Urban parks
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Stability of mine ventilation system based on multiple regression analysis 被引量:12
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作者 JIA Ting-gui LIU Jian 《Mining Science and Technology》 EI CAS 2009年第4期463-466,共4页
In order to overcome the disadvantages of diagonal connection structures that are complex and for which it is difficult to derive the discriminant of the airflow directions of airways, we have applied a multiple regre... In order to overcome the disadvantages of diagonal connection structures that are complex and for which it is difficult to derive the discriminant of the airflow directions of airways, we have applied a multiple regression method to analyze the effect, of changing the rules of mine airflows, on the stability of a mine ventilation system. The amount of air ( Qj ) is determined for the major airway and an optimum regression equation was derived for Qi as a function of the independent variable ( Ri ), i.e., the venti- lation resistance between different airways. Therefore, corresponding countermeasures are proposed according to the changes in airflows. The calculated results agree very well with our practical situation, indicating that multiple regression analysis is simple, quick and practical and is therefore an effective method to analyze the stability of mine ventilation systems. 展开更多
关键词 ventilation network STABILITY diagonal connection multiple regression analysis
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Discrimination of Transgenic Rice Based on Near Infrared Reflectance Spectroscopy and Partial Least Squares Regression Discriminant Analysis 被引量:7
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作者 ZHANG Long WANG Shan-shan +2 位作者 DING Yan-fei PAN Jia-rong ZHU Cheng 《Rice science》 SCIE CSCD 2015年第5期245-249,共5页
Near infrared reflectance spectroscopy (NIRS), a non-destructive measurement technique, was combined with partial least squares regression discrimiant analysis (PLS-DA) to discriminate the transgenic (TCTP and mi... Near infrared reflectance spectroscopy (NIRS), a non-destructive measurement technique, was combined with partial least squares regression discrimiant analysis (PLS-DA) to discriminate the transgenic (TCTP and mi166) and wild type (Zhonghua 11) rice. Furthermore, rice lines transformed with protein gene (OsTCTP) and regulation gene (Osmi166) were also discriminated by the NIRS method. The performances of PLS-DA in spectral ranges of 4 000-8 000 cm-1 and 4 000-10 000 cm-1 were compared to obtain the optimal spectral range. As a result, the transgenic and wild type rice were distinguished from each other in the range of 4 000-10 000 cm-1, and the correct classification rate was 100.0% in the validation test. The transgenic rice TCTP and mi166 were also distinguished from each other in the range of 4 000-10 000 cm-1, and the correct classification rate was also 100.0%. In conclusion, NIRS combined with PLS-DA can be used for the discrimination of transgenic rice. 展开更多
关键词 near infrared reflectance spectroscopy genetically-modified food regulation gene protein gene partial least squares regression discrimiant analysis
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Is analysis of lower esophageal sphincter vector volumes of value in diagnosing gastroesophageal reflux disease? 被引量:3
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作者 Robert E.Marsh Christopher L.Perdue +4 位作者 Ziad T.Awad Patrice Watson Mohamed Selima Richard E.Davis Charles J.Filipi 《World Journal of Gastroenterology》 SCIE CAS CSCD 2003年第1期174-178,共5页
AIM:With successful surgical treatment of gastroesophageal reflux disease(GERD),there is interest in understanding the anti-reflux barrier and its mechanisms of failure.To date, the potential use of vector volumes to ... AIM:With successful surgical treatment of gastroesophageal reflux disease(GERD),there is interest in understanding the anti-reflux barrier and its mechanisms of failure.To date, the potential use of vector volumes to predict the DeMeester score has not been adequately explored. METHODS:627 patients in the referral database received esophageal manometry and ambulatory 24-hour pH monitoring.Study data included LES resting pressure(LESP), overall LES length(OL)and abdominal length(AL),total vector volume(TVV)and intrabdominal vector volume(IVV). RESULTS:In cases where LESP,TVV or IVV were all below normal,there was an 81.4%probability of a positive DeMeester score.In cases where all three were normal, there was an 86.9%probability that the DeMeester score would be negative.Receiver-operating characteristics(ROC) for LESP,TVV and IVV were nearly identical and indicated no useful cut-off values.Logistic regression demonstrated that LESP and IVV had the strongest association with a positive DeMeester score;however,the regression formula was only 76.1%accurate. CONCLUSION:While the indices based on TVV,IVV and LESP are more sensitive and specific,respectively,than any single measurement,the measurement of vector volumes does not add significantly to the diagnosis of GERD. 展开更多
关键词 ADOLESCENT ADULT Aged Aged 80 and over CHILD Child Preschool Esophagogastric Junction Female Gastroesophageal Reflux Humans Hydrogen-Ion Concentration Male MANOMETRY Middle Aged ROC Curve Regression analysis
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Sensitivity analysis of Biome-BGCMuSo for gross and net primary productivity of typical forests in China 被引量:3
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作者 Hongge Ren Li Zhang +2 位作者 Min Yan Xin Tian Xingbo Zheng 《Forest Ecosystems》 SCIE CSCD 2022年第1期111-123,共13页
Background:Process-based models are widely used to simulate forest productivity,but complex parameterization and calibration challenge the application and development of these models.Sensitivity analysis of numerous p... Background:Process-based models are widely used to simulate forest productivity,but complex parameterization and calibration challenge the application and development of these models.Sensitivity analysis of numerous parameters is an essential step in model calibration and carbon flux simulation.However,parameters are not dependent on each other,and the results of sensitivity analysis usually vary due to different forest types and regions.Hence,global and representative sensitivity analysis would provide reliable information for simple calibration.Methods:To determine the contributions of input parameters to gross primary productivity(GPP)and net primary productivity(NPP),regression analysis and extended Fourier amplitude sensitivity testing(EFAST)were conducted for Biome-BGCMuSo to calculate the sensitivity index of the parameters at four observation sites under climate gradient from ChinaFLUX.Results:Generally,GPP and NPP were highly sensitive to C:Nleaf(C:N of leaves),Wint(canopy water interception coefficient),k(canopy light extinction coefficient),FLNR(fraction of leaf N in Rubisco),MRpern(coefficient of linear relationship between tissue N and maintenance respiration),VPDf(vapor pressure deficit complete conductance reduction),and SLA1(canopy average specific leaf area in phenological phase 1)at all observation sites.Various sensitive parameters occurred at four observation sites within different climate zones.GPP and NPP were particularly sensitive to FLNR,SLA1 and Wint,and C:Nleaf in temperate,alpine and subtropical zones,respectively.Conclusions:The results indicated that sensitivity parameters of China's forest ecosystems change with climate gradient.We found that parameter calibration should be performed according to plant functional type(PFT),and more attention needs to be paid to the differences in climate and environment.These findings contribute to determining the target parameters in field experiments and model calibration. 展开更多
关键词 Sensitivity analysis Biome-BGCMuSo PRODUCTIVITY Regression analysis EFAST
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