Preliminary Study on the Linear Relationship between the Internal Pressure Head of Rubber Dam Bags and Real-time Dam Height

The design operating conditions of rubber dams were analyzed,and it is found that the operating conditions are similar to the actual operating conditions of changes in the internal pressure ratio of a specific rubber dam bag in the process of filling and draining. Based on this,the linear relationship curve between the internal pressure head H0 and the real-time dam height H and its approximate analytical formula can be obtained,which can be used as a supplement and correction method for the measurement method of real-time dam height during rubber dam operation,and provides reference for rubber dam project managers.

A linear relationship between De Ritis ratio and mortality in hospitalized patients with COVID-19:A secondary analysis based on a large retrospective cohort study

Background and aims:Although some studies have identified a possible link between the De Ritis ratio and the mortality of patients with COVID-19),the predictive value and the optimal cut-value remain unclear.This study aimed to explore the correlation between the De Ritis ratio and mortality in hospitalized COVID-19.Methods:The data for this cohort study came from a retrospective cohort study that was carried out in a medical system in New York City.The primary outcome was the in-hospital mortality of included patients.The researchers ran multivariate Cox regression analyses,curve fitting,and subgroup analysis to support our findings.Overall survival in different De Ritis ratio groups was plotted as Kaplan-Meier survival curves.Results:The study enrolled 4371 participants with COVID-19 from March 1,2020 to April 16,2020.The overall mortality was 24.8%(1082/4371).The curve fitting analyses indicated that the De Ritis ratio has a positive linear connection with mortality in patients with COVID-19.After adjusting for all covariates,participants with a De Ritis ratio≥2 exhibited 1.29 times the risk of in-hospital mortality compared with those with a De Ritis ratio<1(hazard ratio 1.29,95%confidence interval 1.02-1.62,p=0.031).The p for trend was<0.05 for all models.Patients in the group with a De Ritis ratio≥2 experienced the shortest survival time in the Kaplan-Meier survival analysis.Conclusions:A higher baseline De Ritis ratio is correlated with a corresponding higher mortality among hospitalized people with COVID-19.

Linear relationship between the interdecadal and interannual variabilities of North China rainfall in rainy season

Interdecadal and interannual timescales are dominant in the North China rainfall in rainy season (July and August). On the interdecadal timescale, the North China rainfall exhibited an abrupt decrease at the end of 1970s. In this study, we examined the effect of this abrupt rainfall decrease on the association between rainfall and circulation on the interannual timescale, and found that the interdecadal variation does not change the physical mechanism responsible for the interannual variation of North China rainfall. There is a linear relationship between the interdecadal and interannual variabilities of North China rainfall in rainy season.

STRONGLY CONSISTENT ESTIMATION FOR A MULTIVARIATE LINEAR RELATIONSHIP MODEL WITH ESTIMATED COVARIANCES MATRIX

In this paper, a multivariate linear functional relationship model, where the covariance matrix of the observational errors is not restricted, is considered. The parameter estimation of this model is discussed. The estimators are shown to be a strongly consistent estimation under some mild conditions on the incidental parameters.

Effect of Ionic Liquid on Retention of Solutes on C_(18) Column Based on Linear Solvation Energy Relationships

Several chromatography systems with ionic liquids and a mixture of water with the modifier as mobile phase were characterized via the linear solvation energy relationships（LSER） model. The effects of the ionic liquids and modifier（methanol） concentrations on the retention of 10 solutes（caffeine, pyridine, aniline, phenol, methylparaben, acetopenone, m-cresol, p-cresol, o-cresol, and benzene） were discussed. The LSER model demonstrated high potential to predict retention factors with high squared correlation coefficients（r^2〉 0.97）. A comparison of predictable and experimental retention factors revealed that LSER can adequately reproduce the experimental retention factors of the solutes under different investigated experimental conditions. This model is a helpful tool to evaluate the retention characteristics of ionic liquid systems and to understand the interactions of solutes and ionic liquids.

Linear Free Energy Relationships in Extraction of Rare Earths by Acidic Organophosphorus Extractants

The correlation relationships of apparent extraction equilibrium constant (1gK(ex)) with the electronic effect parameter( Sigma sigma(Phi)) and the steric effect parameter ( Sigma upsilon ) of the substituents in extractant molecules are investigated by linear regression analysis in the extraction of rare earths by various classes and structures of monoacidic organophosphorus extractants. The results indicate that in Linear free energy relationship formula 1gK(ex) = rho Sigma sigma(Phi) + psi Sigma upsilon + h generally follows for this kind of extraction systems. Accordingly, the quantitative structure-behaviour relationships of extractants are discussed. These relationships can be preliminarily applied to predict the 1gK(ex) values of rare earth extraction with definite structures of this class of extractants, and thus can provide some directions for the design of new RE extractants.

收入不平衡、共享发展与居民幸福感

改革开放以来,我国经济发展取得了举世瞩目的成就,但收入不平衡和共享发展程度较低的问题仍然较为突出,这在一定程度上不利于居民幸福感的提升.采用中国家庭追踪调查数据,实证检验了收入不平衡、共享发展与居民幸福感之间的关系.研究发现,收入不平衡与居民幸福感之间存在非线性的倒U型关系,并且共享发展发挥了重要的调节效应,使得共享发展程度较高的群体对收入不平衡更加包容,而且更易发挥收入不平衡对居民幸福感的提升作用.精准扶贫、乡村振兴和社会保障支出等政策也有助于提升居民幸福感对收入不平衡的包容度.因此,政府相关部门应积极实施有效举措降低收入不平衡、多措并举提升共享发展水平并着力落实扶贫类和保障类政策,进一步提升居民家庭的幸福感,加快实现共同富裕的伟大目标.

Relationships between Rainy Days,Mean Daily Intensity and Seasonal Rainfall in Normal,Flood and Drought Years over India

here are limitations in using the seasonal rainfall total in studies of Monsoon rainfall climatology. A correlation analysis of the individual station seasonal rainfall with all India seasonal mean rainfall has been made. After taking the significance test (strictly up to 5% level) the stations which are significantly correlated have been considered in this study in normal, flood and drought years respectively. Analysis of seasonal rainfall data of 50 stations spread over a period of 41 years suggests that a linear relationship fits better than the logarithmic relationship when seasonal rainfall versus number of rainy days is studied. The linear relationship is also found to be better in the case of seasonal rainfall versus mean daily intensity.

Quantitative Structure-biodegradability Relationship Study about the Aerobic Biodegradation of Some Aromatic Compounds

10 quantum chemical descriptors of 21 aromatic compounds have been calculated by the semi-empirical quantum chemical method AM1. The Quantitative Structure-Biodegradability Relationships （QSBR） studies were performed by the multiple linear regression （MLR）, principal component regression （PCR） and back propagation artificial neural network （BP-ANN）, respectively. The root mean square error （RMSE） of the training and validation sets of the BP-ANN model are 0.1363 and 0.0244, the mean absolute percentage errors （MAPE） are 0.1638 and 0.0326, the squared correlation coefficients （R^2） are 0.9853 and 0.9996, respectively. The results show that the BP-ANN model achieved a better prediction result than those of MLR and PCR. In addition, some insights into the structural factors affecting the aerobic biodegradation mechanism were discussed in detail.

Hormesis has emerged as a more common and fundamental dose-response model than the threshold or linear-no-threshold(LNT) models

在回顾传统的有阈和线性无阈的剂量-反应关系的基础上,分析此类该模型被毒理学领域认同的主要原因和其在预测低剂量效应中的缺陷,进而提出了高剂量接触呈现抑制效应,而低剂量却呈现促进或刺激作用这一全面的激效兴奋性剂量-反应关系,弥补了现有模型的不足,并充分论证这种激效性剂量-反应关系在不同种属、接触因素和生物学终点中的普遍性,并探讨了不同物质的激效兴奋作用的可能机制以及激效兴奋模型的三大优点,最后提出了激效模型谋求广泛接受的现实困难和发展趋势。

Structural Characterization of Volatile Components of Rosa Banksiae Ait for Estimation and Prediction of Their Linear Retention Indices and Retention Times

The molecular electronegativity-distance vector （MEDV） was used to describe the molecular structure of volatile components of Rosa banksiae Ait, and QSRR model was built up by use of multiple linear regression （MLR）. Furthermore, in virtue of variable screening by the stepwise multiple regression technique, the QSRR models of 10 and 6 variables and linear retention index （LRI） 10, 7 and 6 varieables were built up by combinating MEDV with the Ultra2 column GC retention time （tR） of 53 volatile components of Rosa Banksiae Air. The multiple correlation coefficients （R） of modeling calculation values of QSRR model were 0.906, 0.906, 0.949, 0.943 and 0.949, respectively. The cross-verification multiple correlation coefficients （RCV） were 0.903, 0.904, 0.867, 0.901 and 0.904, respectively. The results show that the models constructed could provide estimation stability and favorable predictive ability.

山西地磁台阵受晋南线高压直流输电接地极干扰的特征分析与处理

2014年9月山西省地震局与中国地震局地球物理研究所在山西北部恒山断裂带区域共同建设了地磁台阵,布设了5台GM4型磁通门磁力仪,安装于代县、山阴、应县、繁峙和怀仁,以获取区域场地磁三分量观测资料,台阵的5个测点位于高压直流输电晋南线接地极附近。通过对比山西地磁台阵5个测点GM4型磁通门磁力仪与其他台站地磁秒数据,量算出高压直流输电线路(晋北—南京)对山西地磁台阵地磁数据干扰幅度,对其进行相关性和误差分析,求得拟合公式。结果表明,山西地磁台阵受晋南线高压直流输电干扰,Z分量变化幅度随台站位置至晋南线垂直距离增加而减小,H、D分量干扰幅度与Z分量干扰幅度线性相关,以Z分量变化量为因变量,使用参考拟合公式求取的H、D分量变化量,可应用于山西地磁台阵受晋南线高压直流输电干扰的日常处理工作。

锦鲤疱疹病毒微滴式数字PCR检测方法的建立及临床应用

【目的】构建一种敏感性高、特异性强、重复性好的锦鲤疱疹病毒(Koi herpesvirus,KHV)微滴式数字PCR(ddPCR)检测方法,为锦鲤疱疹病毒的定量检测和低浓度样品检测提供技术支持。【方法】参照靶位基因锦鲤疱疹病毒TK基因(GenBank登录号:KX609547.1)设计合成引物和探针,通过比对筛选出最佳引物探针,优化反应体系和退火温度,建立与实时荧光PCR方法的线性关系,并分析该方法的敏感性、特异性、重复性,最后应用于临床样品检测。【结果】当引物、探针浓度分别为900、300 nmol/L且退火温度为57℃时,建立的KHVddPCR扩增反应效率最高,阴阳性微滴分布界限最为明显。KHVddPCR敏感性强,检测限低至0.46拷贝/μL,在0~8.1×10^(4)拷贝/μL范围内,与实时荧光PCR检测结果的线性关系较佳(R2=0.9949)。检测变异系数低,批内变异系数为2.70%,批间变异系数为3.02%。与鲤浮肿病毒、鲫造血器官坏死病毒、真鲷虹彩病毒、草鱼出血病毒、罗非鱼湖病毒、十足目虹彩病毒、虾肝肠胞虫(Enterocytozoon hepatopenaei)和诺卡氏菌(Nocardia seriolae)等其他8种常见的水生动物疫病阳性样品无非特异性反应。在88份的临床样品检测中,阳性2份,阳性检出率为2.27%;在8份能力验证样品检测中,5份阳性,与能力验证满意结果一致,与实时荧光PCR方法和套式PCR方法检测结果一致。【结论】建立的锦鲤疱疹病毒ddPCR检测方法敏感性高、特异性强、重复性好,可定量检测锦鲤疱疹病毒DNA,为锦鲤疱疹病毒的研究提供参考。

Quantitative Structure-activity Relationship(QSAR) Study of Toxicity of Substituted Aromatic Compounds to Photobacterium Phosphoreum

With the artificial neural network（ANN） method combined with the multiple linear regression（MLR）,based on a series of quantum chemical descriptors and molecular connectivity indexes,quantitative structure-activity relationship（QSAR） models to predict the acute toxicity（-lgEC50） of substituted aromatic compounds to Photobacterium phosphoreum were established.Four molecular descriptors that appear in the MLR model,namely,the second order valence molecular connectivity index（2XV）,the energy of the highest occupied molecular orbital（EHOMO）,the logarithm of n-octyl alcohol/water partition coefficient（logKow） and the Connolly molecular area（MA）,were inputs of the ANN model.The root-mean-square error（RMSE） of the training and validation sets of the ANN model are 0.1359 and 0.2523,and the correlation coefficient（R） is 0.9810 and 0.8681,respectively.The leave-one-out（LOO） cross validated correlation coefficient（Q L2OO） of the MLR and ANN models is 0.6954 and 0.6708,respectively.The result showed that the two methods are complementary in the calculations.The regression method gave support to the neural network with physical explanation,and the neural network method gave a more accurate model for QSAR.In addition,some insights into the structural factors affecting the acute toxicity and toxicity mechanism of substituted aromatic compounds were discussed.

矿山充填新型胶凝材料添加量与充填体抗压强度关系研究

工业废渣粉煤灰具有胶凝特性,基于此成功研制出一种用于矿山井下充填的新型胶凝材料。为能够在不同抗压强度要求下快速准确地计算出胶凝材料的添加量,通过进行抗压强度试验,并利用一元线性回归法拟合出不同养护龄期下充填试块抗压强度与胶凝材料添加量之间的数量关系。研究结果表明,研发的新型胶凝材料不仅有效地解决了粉煤灰排放所带来的环境污染问题,同时由于以粉煤灰为主要成分的胶凝材料成本相对低廉,降低了充填成本,使充填采矿法在矿山开采中能得到更广泛的应用。

数字经济影响农村产业融合的机理研究——基于中国省域面板数据的实证研究

基于2011—2021年中国省级面板数据,采用固定效应模型、面板门槛回归模型等实证检验数字经济对农村产业融合发展的影响及其非线性关系。研究发现:(1)数字经济显著促进了我国农村产业融合发展,该结论经过一系列稳健性检验、内生性处理后依然成立。(2)数字经济对农村产业融合发展的促进作用存在边际效应递减的非线性特征,资本积累水平、居民消费水平、高质量人力资本水平在这一促进作用中发挥门槛效应。(3)随着农村产业融合发展水平的提高,数字经济对农村产业融合发展的促进作用呈现出由弱逐渐变强再弱化的趋势,相较于西部地区,数字经济在东、中部地区对农村产业融合发展的促进作用较弱。为充分发挥数字经济促进农村产业融合发展的积极效应,需要在加快发展数字经济、推进数字乡村建设的同时,促进金融创新、缓解金融约束,推进共同富裕、提振消费信心,重视人才培养与引进、保障人才供给。

Enhancing Software Effort Estimation:A Hybrid Model Combining LSTM and Random Forest

Effort estimation plays a crucial role in software development projects,aiding in resource allocation,project planning,and risk management.Traditional estimation techniques often struggle to provide accurate estimates due to the complex nature of software projects.In recent years,machine learning approaches have shown promise in improving the accuracy of effort estimation models.This study proposes a hybrid model that combines Long Short-Term Memory(LSTM)and Random Forest(RF)algorithms to enhance software effort estimation.The proposed hybrid model takes advantage of the strengths of both LSTM and RF algorithms.To evaluate the performance of the hybrid model,an extensive set of software development projects is used as the experimental dataset.The experimental results demonstrate that the proposed hybrid model outperforms traditional estimation techniques in terms of accuracy and reliability.The integration of LSTM and RF enables the model to efficiently capture temporal dependencies and non-linear interactions in the software development data.The hybrid model enhances estimation accuracy,enabling project managers and stakeholders to make more precise predictions of effort needed for upcoming software projects.

昆明泥炭土压缩指标与基本物理指标相关性研究

泥炭土作为一种对建筑物沉降有着重要影响的特殊土,其压缩指标是影响工程安全的关键指标。对昆明地区勘察数据中的压缩系数和压缩指数进行了回归分析,并建立了回归模型,开展了昆明地区4个不同场地泥炭土一维固结试验,基于试验结果和国内外类似经验公式验证了回归模型的适用性。结果表明:压缩系数α_(1-2)、压缩指数C_(c)与天然含水率ω_(0)、初始孔隙比e_(0)具有高度相关线性关系,其中压缩指数与初始孔隙比的关系为C_(c)=0.15e_(0)-0.17;回归模型与试验结果及国内外类似经验公式有较好的一致性。

Predicting the Acute Toxicity of Aromatic Amines by Linear and Nonlinear Regression Methods

In current paper, a quantitative structure-activity relationship （QSAR） study was performed for the prediction of acute toxicity of aromatic amines. A set of 56 compounds was randomly divided into a training set of 46 compounds and a test set of 10 compounds. The electronic and topological descriptors computed by the Scigress package and Dragon software were used as predictor variables. Multiple linear regression （MLR） and support vector machine （SVM） were utilized to build the linear and nonlinear QSAR models, respectively. The obtained models with five descriptors show strong predictive ability. The linear model fits the training set with R2 = 0.71, with higher SVM values of R2 = 0.77. The validation results obtained from the test set indicate that the SVM model is comparable or superior to that obtained by MLR, both in terms of prediction ability and robustness.

Quantitative Structure-retention Relationship Study of Volatile Components from Rosa Banksiae Ait

In the present study,（QSRR） study had been carried out for volatile components from Rosa banksiae Ait.based on various quantum-chemical and physicochemical descriptors derived by B3LYP method.To build QSRR models,a multiple linear regression （MLR） stepwise method was used.The generated models have good predictive ability and are of high statistical significance with good correlation coefficients （R2≥0.734） and p values far less than 0.05.Preliminary results indicated that the application of the models,especially the prediction of GC retention time and linear retention index of volatile components from Rosa banksiae Ait.,will be helpful.The models contribute also to the identification of important quantum-chemical and physicochemical descriptors responsible for the retention time and linear retention index.It was found that the shape attribute （ShpA） and logP value play a vital role in determining component’s GC retention time and linear retention index which increase with the lipophilicity of volatile components.The larger the shape attribute of analyte is,the larger the deformability is,the stronger the interaction between analyte and stationary phase is,and the longer the GC retention time is,the larger the linear retention index is.The importance of E HOMO,q＋,and SEV is also embodied in models,but they are not dominant.