Relationship between Inter Canine Width and Inter Alar Width, Inter Commissural Width, and Inter Canthal Distance: A Pilot Study

The aim of this study was to determine the relationship between inter canine width (ICW) and inter alar width (IAW), inter commissural width (ICoW), and inter canthal distance (ICaD) in Bantu population. Materials and Methods: It was a pilot study included all participants who were aged at least 18 years, without a history of orthodontics treatment from Prosthodontics Department, Faculty of Dental Medicine, University of Kinshasa. The Ethics committee of the National Center of Research for Dental Sciences in DR Congo approved the study protocol (CNRSB 1504.218). The participants medical records were obtained from the interview and dental examination. Nature of the study was explained with participant information sheet, and an informed consent of all participants was obtained. The inclusion criteria were no missing maxillary and mandibular teeth, no diastema, and no anterior restorations, 18 years old before enrollment in the study. The exclusion criteria were inability to meet the above requirements, pregnancy, and refusal to participate in the study. The inter-canine width (ICW), inter alar width (IAW), inter canthal distance (ICaD) and inter-commissural width (ICoW) of each participant were measured with a digital Vernier caliper (Mitutoyo, UK Ltd.,) (0.01 mm) three times and the average value was recorded. The inter canthal distance (ICaD) was measured without applying pressure by bringing the recording parts of the caliper just in contact with the medial angle. The inter alar width (IAW) was marked with a fine marked pencil on the widest outer surface of the alae of the nose on either side or width. Those two points were measured without applying pressure by bringing the recording parts of the caliper just in contact with the outer surface. The participant was told to stop breathing shortly to avoid any change in shape of the nose. The inter-commissural width (ICoW) was determined by measuring the maxillary lip vermilion from commissure to commissure without the application of pressure on the tissue in the relaxed state. The inter-canine width (ICW) was measured indirectly using a dental floss. A dental floss was marked on one end prior to placement in the mouth. Using that point as reference, the dental floss was circumference along the curvature of the anterior dentition such that it passed along the contact point of all the teeth. The distal end of the canine teeth on both sides was then marked on the floss while it was stretched in the patients mouth. Floss was marked on both sides with the marker pencil. The distance between the two proximal contact points was measured and recorded. Data, analysis and validation were performed by the SPSS software (version 22.0, IBM SPSS Statistics, Chicago, IL, USA). Unpaired t-test was used, of Kolmogorov-Smirnov test. Analysis of variance (ANOVA) test was used to test for comparability between socio-demographic characteristics dental measurements. Pearsons correlation coefficients test was calculated to determine the relationship between facial and dental parameters. Significance was set at P 0.01. Results: Of 314 participants enrolled, 202 were included. The age ranged from 18 to 68 years, with a mean age of 40.62 12.99 years. Although the Pearsons correlation coefficients were negative. Ninety-three participants (46%) were men and one hundred and nine (54%) were women. The overall mean age was 40.62 12.99 years. Facial and dental measurements were greater in women than men with significant differences for ICW (p = 0.04). However, no significant difference was seen between men and women for IAW, ICaD and ICoW (p = 0.44, p = 0.23, p = 0.31 respectively). The correlation including Pearsons correlation coefficient and P-values for all participants is not demonstrated. Conclusion: Within the limitations of this study, the results suggest that IAW, ICaD and ICoW cannot be used as a preliminary method for determining the width of the maxillary for anterior teeth for edentulous patients.

APPLICATION OF LEAST MEDIAN OF SQUARED ORTHOGONAL DISTANCE (LMD) AND LMD BASED REWEIGHTED LEAST SQUARES (RLS) METHODS ON THE STOCK RECRUITMENT RELATIONSHIP

Analysis of stock recruitment (SR) data is most often done by fitting various SR relationship curves to the data. Fish population dynamics data often have stochastic variations and measurement errors, which usually result in a biased regression analysis. This paper presents a robust regression method, least median of squared orthogonal distance (LMD), which is insensitive to abnormal values in the dependent and independent variables in a regression analysis. Outliers that have significantly different variance from the rest of the data can be identified in a residual analysis. Then, the least squares (LS) method is applied to the SR data with defined outliers being down weighted. The application of LMD and LMD based Reweighted Least Squares (RLS) method to simulated and real fisheries SR data is explored.

Quantitative Structure-retention Relationship Study of Polychlorinated Dibenzothiophenes by Molecular Electronegativity Distance Vector(MEDV)

Polychlorinated dibenzothiophenes（PCDTs） are classified as persistent organic pollutants in the environment,so the analysis of PCDTs by their gas chromatographic behaviors is of great significance.Quantitative structure-retention relationship（QSRR） analysis is a useful technique capable of relating chromatographic retention time to the molecular structure.In this paper,a QSRR study of 37 PCDTs was carried out by using molecular electronegativity distance vector（MEDV） descriptors and multiple linear regression（MLR） and partial least-squares regression（PLS） methods.The correlation coefficient R of established MLR,PLS models,leave-one-out（LOO） cross-validation（CV）,Q2ext were 0.9951,0.9942,0.9839（MLR） and 0.9925,0.9915,0.9833（PLS）,respectively.Results showed that the model exhibited excellent estimate capability for internal sample set and good predictive capability for external sample set.By using MEDV descriptors,the QSRR model can provide a simple and rapid way to predict the gas-chromatographic retention indices of polychlorinated dibenzothiophenes in conditions of lacking standard samples or poor experimental conditions.

A prediction model for horizontal run-out distance of landslides triggered by Wenchuan earthquake

The peak ground acceleration （PGA）, the volume of a sliding mass V, the height of a mountain HL and the slope angle θ of a mountain are four important parameters affecting the horizontal run-out distance of a landslide L. Correlations among them are studied statistically based on field investigations from 67 landslides triggered by the ground shaking and other factors during the Wenchuan earthquake, and then a prediction model for horizontal run-out distance L is developed in this study. This model gives due consideration to the implications of the above four parameters on the horizontal run-out distance L and the validity of the model is verified by the Donghekou and Magong Woqian landslides. At the same time, the advantages of the model are shown by comparing it with two other common prediction methods. The major findings drawn from the analyses and comparisons are： （1） an exponential relationship exists between L and log V, L and log HL, L and log PGA separately, but a negative exponential relationship exists between L and log tan0, which agrees with the statistical results; and （2） according to the analysis results of the relative relationship between the height of a mountain （H） and the place where the landslides occur, the probabilities at distances of2H/3-H, H/3-2H/3, and O-H/3 are 70.8%, 15.4%, and 13.8%, respectively, revealing that most landslides occurred at a distance of H/2-H. This prediction model can provide an effective technical support for the prevention and mitigation of landslide hazards.

QSRR Study on the Components of Styrax Japonicus Sieb Flowers Using Improved Molecular Electronegativity-distance Vector (I-MEDV)

Atoms in most organic molecules are often carbon,oxygen,nitrogen,sulfur,halogens,etc. Based on the three-dimensional structure of a molecule,a molecular structural characterization（MSC） method called improved molecular electronegativity-distance vector（I-MEDV） was developed. It was used to describe the structures of 37 compounds of styrax japonicus sieb flowers. Through multiple linear regression（MLR）,a QSRR model was built up. The correlation coefficient（R1） of the model was 0.980. Then,4 vectors were selected to build another model through the method of stepwise multiple regression（SMR） ,and the correlation coefficient（R2） of the model was 0.975. Moreover,all the two models were evaluated by performing the crossvalidation with the leave-one-out（LOO） procedure and the correlation coefficients（Rcv） were 0.948 and 0.968,respectively. The results show that the I-MEDV could successfully describe the structures of organic compounds. The stability and predictability of the models were good.

“外察”与“内省”:环境威胁引发的绿色消费意愿研究——基于道德情绪的双路径模型

营销学者在探究绿色消费议题方面做了众多开创性工作,然而针对诱因不同的环境威胁是否及通过怎样的心理路径影响消费者绿色消费意愿的研究仍然匮乏。本文将环境威胁分为自然因素引发的环境威胁和人为因素引发的环境威胁两类,通过4组实验检验了两类环境威胁影响消费者绿色消费意愿的心理机制。研究结果证实了无论哪类环境威胁,都会对绿色产品购买行为产生积极影响,但不同类型的环境威胁会通过差异化认知过程和情绪反应影响绿色产品购买行为。当消费者面对自然因素引发的环境威胁时,其“外察”思维模式会起主导作用,此时敬畏感是促进绿色产品购买意愿的中介变量;当消费者面对人为因素引发的环境威胁时,其“内省”思维模式会起主导作用,此时内疚感是促进绿色产品购买意愿的中介变量。研究也证实了环境威胁对道德情绪的影响会受自然联结性和道德提升感的调节。

基于氢谱修饰指数的润滑油添加剂抗磨损性能的预测研究

润滑油添加剂对保障机械运行的稳定性和安全性、延长设备的使用寿命、节约能耗具有重要作用,由于通过实验获得数据费时费力,故用定量结构摩擦性能关系研究方法,来获取抗磨损性能数据成为一种简便而高效的方法.为研究酰肼类及磷酸类润滑油添加剂抗磨损性能与结构的关系,定义并建构了新的氢谱修饰指数^(0)H,并计算36个酰肼类及磷酸类分子的电性距离矢量,筛选了M_(2)、M_(3)、M_(21)和M_(59),将这5个结构描述符作为BP神经网络的输入变量,磨损体积量度V s作为神经网络输出变量,用5-3-1的神经网络结构,构建了神经网络法预测模型,模型相关系数0.944,磨损体积量度V s的预测值与文献实验值的平均相对误差为2.61%,优于文献方法结果.结果表明:酰肼类及磷酸类润滑油添加剂抗磨损性能与氢谱修饰指数有良好的非线性关系,影响抗磨损性能的主要因素是分子中原子特性、基团片段的—CH_(3)、—CH_(2)—、>CH—、—O、—N—和—P—等.该研究对指导合成新型抗磨损性能好的化合物分子有理论意义.

文化相近与异地大客户关系的形成及其机制研究

中国“多元一体”的文化格局对跨地区供应链关系形成了隐性壁垒,而两地间的文化相近有助于异地大客户关系的形成与发展。方言距离体现了两地的文化相近程度,方言距离越小,上市公司对该地区大客户的销售占比越高;作用机制在于文化相近提高了公司与客户间的信息交流、促进了信任和认同、提供了先天性的社会资本积累。文化相近的作用存在异质性,在非国有控股上市公司、非国有客户和资产规模较小的上市公司中作用更显著。文化相近对于大客户关系的促进作用依赖于完善的外部正式制度环境,在契约环境较好和市场化程度较高的地区,其作用更显著。最后,文化相近的大客户关系的稳定性更高。

创新要素集聚与城市间均衡发展:“一城独大”还是“携城发展”

随着区域协调发展战略的深入推进,以创新要素推动城市间均衡发展逐渐成为社会共识。首先从理论层面分析了创新要素集聚对城市间均衡发展的直接影响、作用路径及空间效应,随后基于2011—2021年中国273个城市的面板数据,运用双向固定效应模型、调节路径分析模型等实证评估了创新要素集聚与城市间均衡发展的作用关系。研究发现:(1)创新要素集聚与城市间均衡发展之间存在先“一城独大”后“携城发展”的U型关系;(2)创新创业活跃度能够作为创新要素集聚影响城市间均衡发展的作用桥梁;(3)相较于不与省会、直辖市相邻城市和经济发展落后城市,省会、直辖市或与省会、直辖市相邻城市以及经济发展领先城市的创新要素集聚与城市间均衡发展的U型关系表现得更为明显;(4)创新要素集聚对城市间均衡发展的影响具有显著的空间溢出效应,且该效应存在典型的地理距离衰减特征,600km以内创新要素集聚的溢出效应较强。研究有助于识别创新要素集聚对城市间均衡发展的具体影响,能够为缩小区域发展差距、促进经济高质量发展提供有益借鉴。

基于XGBOOST-SHAP的地铁建成环境与站点出行距离的非线性关系研究

相较于传统地铁客流量特征分析,地铁站点平均出行距离的研究可以更加精细化了解地铁网络客流流动性特征。为探究多重建成环境与站点平均出行距离之间的复杂关系,以西安市地铁系统为研究对象,从土地利用、兴趣点分布、周边交通建成环境、站点自身属性等方面构建11种建成环境指标,建立基于极端梯度提升的XGBOOST-SHAP归因分析架构的可解释性机器学习模型,以揭示两者之间的非线性关系。同时,将该模型拟合回归效果与梯度提升决策树(GBDT)及最小二乘回归(OLS)进行比较,以验证XGBOOST模型在拟合回归效果上的优势。结果表明:XGBOOST模型的R方、平均绝对误差(MAE)、均方误差(MSE)值分别为0.75、0.95、1.36,其拟合效果要优于GBDT与OLS模型。站点平均出行距离呈现出明显的环状分布的空间异质性。SHAP归因分析结果表明:距市中心距离特征贡献最大,路网密度、土地利用混合度、公交线路数量以及住宅数量对出行距离的贡献度也相对较高;POI香农熵指数、餐饮服务点对平均出行距离的正负反馈不明显;其余指标对平均出行距离的影响均呈现出正负反馈机制结合的趋势。研究结果对交通需求分析、线路容量优化、运营效果评估等提供了数据支撑,可有效提高地铁交通便利性,满足不同区域的出行需求并改善整个地铁系统的效率和可持续性。

高铁网络发展下的站城空间与功能关系研究--以长三角地区为例

在过去近20年里,中国高铁网络化已成为城市和区域空间发展的重要推动力,各级政府也在不同层面上实施了高铁站区建设与城市空间协同发展策略。为此,建立站城空间及站城功能联系的分析框架,以长三角为案例区,探讨不同类型高铁站的站区发育及站城关系特征。结果表明,长三角地区高铁站城联系具有较大的分异特征,大多站区功能发育水平较低,区域中心城市和部分地级城市与其主要高铁站区之间相互强化发展,而其他高铁城市与站区之间功能联系有待提升,不同类型高铁站的站城功能联系发育水平受站区、城市和区域因素的交互影响。结合站区发展潜力、地区差异化的高铁出行需求、城市空间发展规划,建议提升站城交通服务质量、分类分级培育站区主导功能、优化站城功能联系。

关系强度对农地流转契约选择影响的研究——来自贵州省4县(市)1108户农户的经验证据

基于贵州省4县(市)1108户农户的一手调研数据,利用Probit模型考察关系强度对农地流转契约选择的影响,同时使用改进中介效应模型进一步探讨其内在传导机制。结果表明:关系强度越弱,农户在农地流转时越倾向于采用书面式契约;自然空间距离以及信任在关系强度对农户农地流转契约选择的影响中具有中介效应。上述研究结论的启示为:在经济发展相对落后的农村地区,农地流转过程中的契约选择实质上尚未摆脱社会关系的影响,农地流转双方仍旧会基于关系强度来配置农地资源。因此,中央及各级地方政府在推动农地流转契约正规化的过程中,一定要充分考虑当地差序格局、信任机制以及关系网络等非正式制度供给在乡村治理中所发挥的重要作用。

共享审计空间布局对供应链关系的影响

在全球化经济中,市场竞争已不再是传统的企业“单打独斗”,而是供应链之间的竞争。建立客户供应商持久稳定的沟通合作是提升供应链整体竞争力的基石,稳定的客户关系能够保障供应商的主要收入来源并降低经营不确定性,对企业持续发展至关重要。因此,文章将供应链与共享审计相结合,从区位地理特征出发,关注供应链上下游企业与共享审计这一整体的空间布局对供应链关系的影响,揭示了共享审计的区位特征在提升供应链稳定性和竞争力中的关键作用。以2009-2021年A股上市公司为样本,文章研究发现,供应链与共享审计的地理距离和制度距离越近,客户稳定性越好,供应链关系越持久。进一步分析发现,共享审计对供应链的协同作用主要体现在到客户距离更近的情况下,与当前买方市场占主导地位的现状一致。此外,共享审计的大所更能有效发挥供应链协同作用,稳定供应链关系。文章的发现为供应链管理和共享审计实践提供了新的视角,对增强供应链的抗风险能力和市场竞争力具有重要的理论和实践意义。

关系嵌入和类协方差度量的小样本图像分类

在小样本图像分类的问题情景下,图像之间具有结构性、辨别性的特征关系还未被重视,图像的特征关系匹配不足,导致特征嵌入不完善,度量效果不明显.为了关注图像特征之间的匹配关系,通过关注单个图像的空间信息及匹配图像间的特征,实现度量嵌入特征的关系,提出基于关系嵌入和类协方差度量的网络结构,通过自相关注意表示和交互相关注意来学习图像内和图像间的特征关系.其中,将单个图像的基本特征表示映射成自相关张量,关注其中的通道空间信息,学习图像张量内结构信息.而对于图像对,计算2个图像表示的互关联信息,并生成共同注意,从而得到图像间具有判别性的关系信息.最后用马氏距离度量特征关系.经过大量实验验证之后,在3个小样本基准数据集中评估,并与大量现有方法进行对比,结果显示网络结构对学习特征间关系具有一定的有效性.

How the microenvironment dominated by the distance effect to regulate the FeN_(4)site ORR activity and selectivity?

The distance effect of the doped heteroatoms away from the catalytic centers has rarely been reported.In this work,we conducted density functional theory calculations to thoroughly investigate the influence of heteroatom(N,P,B,and S atoms)doping distance on the oxygen reduction reaction(ORR)activity of graphene-based FeN_(4)sites.We uncovered a Sabatier-like relationship between heteroatom doping distance and ORR activity of FeN_(4)sites.The nearest doping does not significantly improve and even block the ORR activity of FeN_(4)sites.Optimal ORR activity is achieved when the heteroatoms are 4-5Å(N,P,and S atoms)or 6-7Å(B atoms)away from the Fe atoms.Analysis of electronic structure indicates that distance effect can modulate the local chemical environment of Fe atoms,thereby account for the changes in ORR activity along with the doping distance and doping atoms.This study provides insights into the influence of heteroatom doping on the chemical environment of reaction active centers,and provides the theoretical guidance for controlling the doping distance of heteroatoms to achieve optimal catalytic activity and selectivity.

赛博鹊桥:异地恋中的媒介使用与关系再现

随着空间流动的加速与媒介技术的迭代,异地恋正成为当下青年群体中较为普遍的现象。异地恋中的媒介使用架构起了一座赛博鹊桥,协助完成情感的维系与关系的再现。在媒介体验维度上,异地恋情侣综合使用多种社交媒体,打造出跨媒介、跨时空、仪式化的意义空间;在情感参与维度上,异地恋情侣会为亲密关系再现中的“差错”赋予一定的象征意义,进而造成解读错位或社交倦怠,致使亲密关系走向争论乃至断连;在主体感知维度上,恋爱关系中“身体”的重要性与其他人际关系有本质不同,导致了由媒介构建的社会临场感始终在身体层面存在缺憾。对于“身体”的思考也将异地恋研究延伸至更为深远的学理空间,体现出异地恋情感沟通对于传播研究的独特价值。

澜沧江流域捕食线虫真菌空间分布格局及其驱动机制

为明晰历史因素和当代环境因子对流域内微生物空间分布格局的相对重要性,在澜沧江流域内系统布设76个样区,每个样区内采集陆地土壤和水体底泥样品各5份,使用纯培养和单孢分离法获得样品中的捕食线虫真菌(NTF)纯培养物,再结合形态学和分子生物学方法对NTF进行鉴定。通过等距离及按古金沙江与古澜沧江的交汇点为界限的两种方式对澜沧江上中下游进行划分,以此来探究历史因素和当代环境因子对NTF空间分布格局的相对影响。从760份样品中共分离得到3属31种566株NTF,总样品检出率和香农威纳指数分别为49.74%和2.54。澜沧江流域内样品检出率和物种丰富度与环境因子均无显著的相关关系,而澜沧江流域内NTF存在极显著的距离衰减关系(P<0.005)。两种划分方式下的NTF分布模式相似,上下游与部分环境因子出现显著的相关关系,中游仍无显著的相关关系(P>0.05),但历史划分下的中游NTF出现显著的距离衰减关系(P<0.05);且中游的NTF与金沙江上游的物种相似性都较高(0.57和0.59),上游间则较低(均为0.46)。结果表明,NTF在澜沧江流域内存在空间分布格局,古金沙江与古澜沧江的混流历史(历史因素)是关键驱动因子,等距划分流域会模糊历史因素对流域内微生物空间分布格局的影响,而考虑河流演化历史更容易发现此规律。

锥形束CT测量成人上颌前磨牙根尖与上颌窦位置关系及其对即刻种植的影响

目的分析上颌前磨牙牙根与上颌窦空间位置关系,为该位点即刻种植时机、方案、术式及种植体选择等提供解剖依据。方法本研究已通过单位伦理委员会审查批准,并获得患者知情同意。收集2017年1月⁃2023年3月瑞华口腔门诊部就诊的264例患者(年龄20~65岁)口腔锥形束CT(cone beam CT,CBCT)影像,选取冠状面测量上颌前磨牙根尖到上颌窦下壁的最短距离,对牙根与上颌窦下壁的垂直关系分类,并就双侧、性别及不同年龄组进行比较。结果上颌前磨牙根尖至上颌窦下壁最短距离:上颌第一前磨牙单根型中位数为7.34 mm,双根型颊根中位数为7.80 mm,腭根中位数为7.36 mm;上颌第二前磨牙单根型中位数为2.56 mm,双根型中颊根中位数为1.73 mm,腭根中位数为1.23 mm。上颌第二前磨牙右侧单根型根尖至上颌窦下壁间最短距离在各年龄组间有统计学差异(P<0.05),20~29岁组最小(中位数1.52 mm),≥40岁组最大(中位数4.44 mm)。性别和左右侧对根尖到窦下壁距离的影响无统计学差异(P>0.05)。上颌前磨牙根尖与上颌窦垂直关系中,根尖不与上颌窦下壁接触的情况占比最高,垂直关系分类在单根型和双根型间无统计学差异(P>0.05)。结论上颌第一前磨牙根方大多可为即刻种植提供足够高度骨量,较易实现即刻种植;上颌第二前磨牙根方骨量不足常见,需充分利用拔牙窝骨壁或窦底皮质骨实现初期稳定性;根尖与窦下壁垂直关系分型分布受年龄及牙位影响,青年组较其他年龄组更易出现骨高度不足,需谨慎选择即刻种植适应证;牙根数量对牙根与上颌窦垂直关系影响不大,双根型因牙根直径小及根间骨性分隔,可为即刻种植提供更多骨支持。

远程教育新生学习效果与毕业率的关系模型构建

远程教育领域所积累的海量数据,为探索教学规律提供契机。处于关键期的新生,其学习效果与毕业率间的关系研究,为远程教育教学实践提供有力支撑。本研究选取宜宾开放大学2019年春期-2020年春期三届新生4162人为样本,经过数据预处理,运用相关性分析和二次回归分析构建关系模型,旨在通过新生课程合格率预测按期毕业率。结果表明,新生课程合格率的提升可显著增强按期毕业的可能性,而首期课程合格率的降低导致延期毕业比例上升,增加教学管理难度。此外,延长毕业时间,将增加学习者流失风险。因此,建议加强新生的学习适应性教育,构建科学的入学教育模式,以提升学习效果和按期毕业率。

A novel molecular distance edge vector as applied to chemical modeling of quantitative structure-retention relationships:Various gas chromatographic retention behaviors of polychlorinated dibenzofurans on different polarity-varying stationary phases

Based on the identical group as a pseudo atom instead of a typical atom, a novel modified molecular dis-tance-edge (MDE) vector μ was developed in our laboratory to characterize chemical structure of polychlorinated diben-zofurans (PCDFs) congeners and/or isomers. Quantitative structure-retention relationships (QSRRs) between the new VMDE parameters and gas chromatographic (GC) retention behavior of PCDFs were then generated by multiple linear regression (MLR) method for non-polar, moderately polar, and polar stationary phases. Four excellent models with high correlation coefficients, R=0.984-0.995, were proposed for non-polar columns (DB-5, SE-54, OV-101). For the moder-ately polar columns (OV-1701), the correlation coefficient of the developed good model is only 0.958. For the polar col-umns (SP-2300), the QSRR model is poor with R=0.884. Then cross validation with leave-one out of procedure (CV) is performed in high correlation with the non-polar (Rcv=992-0.974) and weakly polar (Rcv=921) columns and in little cor-relation (Rcv=0.834) with the polar columns. These results show that the new μ vector is suitable for describing the re-tention behaviors of PCDFs on non-polar and moderately polar stationary phases and not for the various gas chroma-tographic retention behaviors of PCDFs on the different po-larity-varying stationary phases.