A Novel Hybrid Method for Measuring the Spatial Autocorrelation of Vehicular Crashes: Combining Moran’s Index and Getis-Ord G_i<sup style='margin-left:-7px;'>*</sup>Statistic

Spatial autocorrelation is a measure of the correlation of an observation with other observations through space. Most statistical analyses are based on the assumption that the values of observations are independent of one another. Spatial autocorrelation violates this assumption, because observations at near-by locations are related to each other, and hence, the consideration of spatial autocorrelations has been gaining attention in crash data modeling in recent years, and research have shown that ignoring this factor may lead to a biased estimation of the modeling parameters. This paper examines two spatial autocorrelation indices: Moran’s Index;and Getis-Ord Gi* statistic to measure the spatial autocorrelation of vehicle crashes occurred in Boone County roads in the state of Missouri, USA for the years 2013-2015. Since each index can identify different clustering patterns of crashes, therefore this paper introduces a new hybrid method to identify the crash clustering patterns by combining both Moran’s Index and Gi*?statistic. Results show that the new method can effectively improve the number, extent, and type of crash clustering along roadways.

中国城市群市政基础设施水平综合评价——基于ARCGIS热点分析

“十八大”以来,国家高度重视城市群内部公共设施服务共享、生态环境共治问题,对城市群基础设施水平研究可以为城市群可持续发展提供科学数据。基于5大城市群市政基础数据(2016-2020年),利用因子分析、莫兰指数、ArcGIS的热点分析工具剖析5大城市群基础设施水平。研究结果发现:珠三角城市群的基础设施水平最高,成渝、长江中游城市群等内陆城市的基础设施水平较珠三角、长三角等沿海城市群设施水平差距较大;城市群的空间集聚性明显,珠三角城市群基础设施水平属于“高高聚类”,成渝城市群属于“低低聚类”;基础设施资源配置方面存在分配不均衡问题。

Joint Detection of Serum Vitamin D,Body Mass Index,and Tumor Necrosis Factor Alpha for the Diagnosis of Crohn’s Disease

Objective Vitamin D(VD)deficiency was reported to contribute to the progression of Crohn’s disease(CD)and affect the prognosis of CD patients.This study investigated the role of serum VD,body mass index(BMI),and tumor necrosis factor alpha(TNF-α)in the diagnosis of Crohn’s disease.Methods CD patients(n=76)and healthy subjects(n=76)were enrolled between May 2019 and December 2020.The serum 25-hydroxyvitamin D[25(OH)D]levels,BMI,and TNF-αlevels,together with other biochemical parameters,were assessed before treatment.The diagnostic efficacy of the single and joint detection of serum 25(OH)D,BMI,and TNF-αwas determined using receiver operating characteristic(ROC)curves.Results The levels of 25(OH)D,BMI,and nutritional indicators,including hemoglobin,total protein,albumin,and high-density lipoprotein cholesterol,were much lower,and the TNF-αlevels were much higher in the CD patients than in the healthy subjects(P<0.05 for all).The areas under the ROC curve for the single detection of 25(OH)D,BMI,and TNF-αwere 0.887,0.896,and 0.838,respectively,with the optimal cutoff values being 20.64 ng/mL,19.77 kg/m^(2),and 6.85 fmol/mL,respectively.The diagnostic efficacy of the joint detection of 25(OH)D,BMI,and TNF-αwas the highest,with an area under the ROC curve of 0.988(95%CI:0.968–1.000).Conclusion The joint detection of 25(OH)D,TNF-α,and BMI showed high sensitivity,specificity,and accuracy in CD diagnosis;thus,it would be effective for the diagnosis of CD in clinical practice.

基于CSLE的泛第三极地区土壤侵蚀强度空间分布特征

[目的]定量评估泛第三极地区的土壤侵蚀状况,明确土壤侵蚀的分布特征,以期为土壤侵蚀的科学防治提供依据。[方法]基于分层不等概系统抽样方法,共布设31 406个调查单元。利用中国土壤流失方程CSLE计算泛第三极地区土壤侵蚀速率,并利用莫兰指数(I)探讨其分布特征。[结果](1)泛第三极地区平均土壤侵蚀速率为162.73 t/(km^(2)·a),水土流失面积比例为7.75%,土壤侵蚀速率超过500 t/(km^(2)·a)的地区主要位于西亚、东亚和南亚;(2)土壤侵蚀存在明显的空间聚集性(I=0.920 9),以高高型和低低型聚集为主,高高型聚集主要分布在西亚北部、南亚北部和西南部以及中国的东北、黄土高原和西藏南部;(3)草地、灌丛和耕地是土壤侵蚀较严重的土地利用类型,其中>1 000 m的草地、>500 m的灌丛和耕地的土壤侵蚀更严重,超过25%的土地都发生了水土流失,平均土壤侵蚀速率变化于426.85~683.72 t/(km^(2)·a)。[结论]海拔介于1 000~6 000 m的草地、500~4 000 m的灌丛以及1 000~4 000 m的耕地是泛第三极地区土壤侵蚀发生的重点区域,需特别关注。

Did weekly economic index and volatility index impact US food sales during the first year of the pandemic?

We explore the impacts of economic and financial dislocations caused by COVID-19 pandemic shocks on food sales in the United States from January 2020 to January 2021.We use the US weekly economic index(WEI)to measure economic dislocations and the Chicago Board Options Exchange volatility index(VIX)to capture the broader stock market dislocations.We validate the NARDL model by testing a battery of models using the autoregressive distributed lags(ARDL)methodology(ARDL,NARDL,and QARDL specifications).Our study postulates that an increase in WEI has a significant negative long-term effect on food sales,whereas a decrease in WEI has no statistically significant(long-run)effect.Thus,policy responses that ignore asymmetric effects and hidden cointegration may fail to promote food security during pandemics.

The diagnostic value of liver stiffness measurement combined with S index in the degree of hepatitis B liver fibrosis

Objective:To investigate the value of liver stiffness measurement(LSM)combined with S index in predicting the degree of liver fibrosis in hepatitis B patients.Methods:A total of 187 chronic hepatitis B patients who were admitted to the Department of Infection,the First Affiliated Hospital of Hainan Medical College from January 2019 to December 2021 were selected.General data were collected,blood routine,liver function,liver fibrosis and liver stiffness measurement were tested,and S index,APRI and FIB-4 index were calculated,and liver biopsy was performed.Results:According to the pathological results of liver puncture,The patients were divided into no significant fibrosis group(n=86),significant fibrosis group(n=71)and cirrhosis group(n=30).There were significant differences in age,PLT,GGT,ALB,S index,HA,LN and LSM levels among the three groups(P<0.05).There was a good correlation between S index and the degree of hepatic fibrosis(rs=0.738,P<0.001).The AUC of S index and LSM for the diagnosis of significant fibrosis in hepatitis B were 0.873 and 0.792,respectively.And the AUC of S index and LSM for the diagnosis of liver cirrhosis were 0.966 and 0.879,respectively.The AUC for the combined diagnosis of significant fibrosis and cirrhosis were 0.908 and 0.988,respectively.The AUROC of combined detection in the diagnosis of cirrhosis was higher than that of LSM,APRI and FIB-4(P<0.05).Conclusion:LSM combined with S index has certain application value in the diagnosis of liver fibrosis/cirrhosis in hepatitis B patients.

基于BiLSTM-Attention的F_(10.7)指数预测模型与中国自主数据集的应用

F_(10.7)指数是太阳活动的重要指标,准确预测F_(10.7)指数有助于预防和缓解太阳活动对无线电通信、导航和卫星通信等领域的影响.基于F_(10.7)射电流量的特性,在双向长短时记忆网络(Bidirectional Long Short-Term Memory Network,BiLSTM)基础上融入注意力机制(Attention),提出了一种基于BiLSTM-Attention的F_(10.7)预报模型.在加拿大DRAO数据集上其平均绝对误差(MAE)为5.38,平均绝对百分比误差(MAPE)控制在5%以内,相关系数(R)高达0.987,与其他RNN模型相比拥有优越的预测性能.针对中国廊坊L&S望远镜观测的F_(10.7)数据集,提出了一种转换平均校准(Conversion Average Calibration,CAC)方法进行数据预处理,处理后的数据与DRAO数据集具有较高的相关性.基于该数据集对比分析了RNN系列模型的预报效果,实验结果表明,BiLSTM-Attention和BiLSTM两种模型在预测F_(10.7)指数方面具有较好的优势,表现出较好的预测性能和稳定性.

New indices to balanceα-diversity against tree size inequality

The number and composition of species in a community can be quantified withα-diversity indices,including species richness(R),Simpson’s index(D),and the Shannon-Wiener index(H΄).In forest communities,there are large variations in tree size among species and individu-als of the same species,which result in differences in eco-logical processes and ecosystem functions.However,tree size inequality(TSI)has been largely neglected in studies using the available diversity indices.The TSI in the diameter at breast height(DBH)data for each of 99920 m×20 m forest census quadrats was quantified using the Gini index(GI),a measure of the inequality of size distribution.The generalized performance equation was used to describe the rotated and right-shifted Lorenz curve of the cumulative proportion of DBH and the cumulative proportion of number of trees per quadrat.We also examined the relationships ofα-diversity indices with the GI using correlation tests.The generalized performance equation effectively described the rotated and right-shifted Lorenz curve of DBH distributions,with most root-mean-square errors(990 out of 999 quadrats)being<0.0030.There were significant positive correlations between each of threeα-diversity indices(i.e.,R,D,and H’)and the GI.Nevertheless,the total abundance of trees in each quadrat did not significantly influence the GI.This means that the TSI increased with increasing spe-cies diversity.Thus,two new indices are proposed that can balanceα-diversity against the extent of TSI in the com-munity:(1−GI)×D,and(1−GI)×H’.These new indices were significantly correlated with the original D and H΄,and did not increase the extent of variation within each group of indices.This study presents a useful tool for quantifying both species diversity and the variation in tree sizes in forest communities,especially in the face of cumulative species loss under global climate change.

Elevation transition of aquatic insects closely matches a thermal feature in the Yungas of Northwestern Argentina

Temperature is a key factor that shapes the distribution of organisms.Having knowledge about how species respond to temperature is relevant to devise strategies for addressing the impacts of climate change.Aquatic insects are particularly vulnerable to climate change,yet there is still much to learn about their ecology and distribution.In the Yungas ecoregion of Northwestern Argentina,cold-and warm-adapted species of the orders Ephemeroptera,Plecoptera,and Trichoptera(EPT)are segregated by elevation.We modeled the ecological niche of South American EPT species in this region using available data and projected their potential distribution in geographic space.Species were grouped based on their ecogeographic similarity,and we analyzed their replacement pattern along elevation gradients,focusing on the ecotone where opposing thermal preferences converge.Along this interface,we identified critical points where the combined incidence of cold and warm assemblages maximizes,indicating a significant transition zone.We found that the Montane Cloud Forest holds the interface,with a particularly greater suitability at its lower boundary.The main axis of the interface runs in a N-S direction and falls between 14°C-16°C mean annual isotherms.The probability of a particular location within a basin being classified as part of the interface increases as Kira’s warmth index approaches a score around 150.Understanding the interface is critical for defining the thermal limits of species distribution and designing biomonitoring programs.Changes in the location of thermal constants related to mountainous ecotones may cause vertical displacement of aquatic insects and vegetation communities.We have recognized significant temperature thresholds that serve as indicators of suitability for the interface.As global warming is anticipated to shift these indicators,we suggest using them to monitor the imprints of climate change on mountain ecosystems.

Association between childhood obesity and gut microbiota:16S rRNA gene sequencing-based cohort study

BACKGROUND This study aimed to identify characteristic gut genera in obese and normal-weight children(8-12 years old)using 16S rDNA sequencing.The research aimed to provide insights for mechanistic studies and prevention strategies for childhood obesity.Thirty normal-weight and thirty age-and sex-matched obese children were included.Questionnaires and body measurements were collected,and fecal samples underwent 16S rDNA sequencing.Significant differences in body mass index(BMI)and body-fat percentage were observed between the groups.Analysis of gut microbiota diversity revealed lowerα-diversity in obese children.Differences in gut microbiota composition were found between the two groups.Prevotella and Firmicutes were more abundant in the obese group,while Bacteroides and Sanguibacteroides were more prevalent in the control group.AIM To identify the characteristic gut genera in obese and normal-weight children(8-12-year-old)using 16S rDNA sequencing,and provide a basis for subsequent mechanistic studies and prevention strategies for childhood obesity.METHODS Thirty each normal-weight,1:1 matched for age and sex,and obese children,with an obese status from 2020 to 2022,were included in the control and obese groups,respectively.Basic information was collected through questionnaires and body measurements were obtained from both obese and normal-weight children.Fecal samples were collected from both groups and subjected to 16S rDNA sequencing using an Illumina MiSeq sequencing platform for gut microbiota diversity analysis.RESULTS Significant differences in BMI and body-fat percentage were observed between the two groups.The Ace and Chao1 indices were significantly lower in the obese group than those in the control group,whereas differences were not significant in the Shannon and Simpson indices.Kruskal-Wallis tests indicated significant differences in unweighted and weighted UniFrac distances between the gut microbiota of normal-weight and obese children(P<0.01),suggesting substantial disparities in both the species and quantity of gut microbiota between the two groups.Prevotella,Firmicutes,Bacteroides,and Sanguibacteroides were more abundant in the obese and control groups,respectively.Heatmap results demonstrated significant differences in the gut microbiota composition between obese and normal-weight children.CONCLUSION Obese children exhibited lowerα-diversity in their gut microbiota than did the normal-weight children.Significant differences were observed in the composition of gut microbiota between obese and normal-weight children.

面向SDGs的黄土高原地区可持续发展水平测度、时空分异及未来趋势研究

联合国2030年可持续发展目标(sustainable development goals,SDGs)的本土化是现阶段落实SDGs的核心任务。针对现有研究空间尺度大、时间尺度短的特点,以黄土高原地区348个县域作为研究区,通过构建指标体系以及采用莫兰指数评估2000—2020年可持续发展水平及时空演进特征,并利用灰色马尔科夫模型对未来可持续发展趋势进行探究。结果表明:黄土高原地区可持续发展水平在2000—2020年呈波动式上升,与中国整体平均水平间的差距逐渐缩小。各县域发展存在一定差距,青海省所辖县域处于绝对的劣势地位。各县域之间的空间正向关联性逐渐缩小,高-高聚集地区越来越多,未来10年可持续发展水平将持续提高。

Existence of Monotone Positive Solution for a Fourth-Order Three-Point BVP with Sign-Changing Green’s Function

This paper is concerned with the following fourth-order three-point boundary value problem , where , we discuss the existence of positive solutions to the above problem by applying to the fixed point theory in cones and iterative technique.

结合均匀度理论和Moran’s I指数、广义G指数的景观格局全局自相关分析

以塔子沟林场为研究区域,以1997年8月28日和2009年8月25日两期Landsat TM遥感影像为主要数据源,辅助大量非遥感数据,借助ENVI 5.1、Arc GIS 10.3和Geoda095i等软件,将均匀度理论分析方法引入到景观格局空间相关分析中,对研究区域景观格局全局自相关进行了分析,并与Moran’s I、广义G指数的分析方法获得结论进行了对比。经计算,1997年的景观格局均匀度为0.320 7,介于景观均匀度置信区间[0.297 2,0.339 7],景观格局判定为随机分布,2009年的景观格局均匀度为0.288 3,小于下限值0.296 9,景观格局判定为聚集分布。1997年Moran’s I值为-0.11,景观格局判定为分散分布,2009年Moran’s I值为0.42,景观格局判定为聚集分布。1997年研究区域Z Score值为0.92,2009年研究区域Z Score值为2.06,根据景观格局判别可知,2009年研究区域景观格局呈现出明显的高值空间聚集(H-H聚集),即该期景观格局为聚集分布。结果表明3种分析方法得到的结论相同,即从1997—2009年的12年间,研究区域的格局状况由随机格局到聚集格局变化,说明将均匀度理论分析方法引入到景观格局空间相关分析中是可行的。

基于遥感和Moran’s I指数的水稻面积变化空间自相关性研究

本研究基于遥感影像获取了2011-2015年江苏省淮安区水稻面积,在乡镇区划和2 km规则网格的基础上,用Moran’s I指数分析了2011-2015年水稻逐年空间变化的相关关系,分析结果表明,淮安区水稻面积变化有聚集现象,2012年有4个聚集区,2013年有3个聚集区,2014年和2015年有6个聚集区;聚集区仅为乡镇行政区划单元的部分区域。

基于空间权重矩阵变化下Moran’s I检验研究

文章运用LEE的矩阵算法,推导出Moran’s I的期望和方差,然后在四类空间权重矩阵及三个空间计量模型下构建蒙特卡洛实验,并以拒绝频率为依据来检测Z检验效果,研究发现:不存在空间相关时,Z检验在各权重矩阵和空间计量模型下的拒绝频率非常接近标准值0.05,表明检验效果较稳健;在空间相关程度不高(￡0.2)时,空间计量模型和空间权重矩阵对Z检验有轻微影响;但在空间相关程度较高(30.4)时,空间模型对Z检验有一定程度的影响,但SAR与SEMAR无差别;而权重矩阵属性与空间单元个数对Z检验影响程度较大,且与空间相关程度有近似正比关系。

基于Moran′s I的菜地土壤属性空间分布格局分析

为探讨时空尺度下露天菜地及设施菜地种植模式对土壤属性空间分布格局的影响,采用Moran′s I空间分析方法,对安徽省肥东县2017年采集的375个表层土样数据、2016年的露天菜地数据及2019年的设施菜地数据之间的空间自相关性进行研究。结果表明:研究区内露天菜地种植时间越短,土壤全氮、速效钾的平均值越高,设施菜地种植时间越短,有机质、全氮、有效磷、速效钾、pH 5种土壤属性平均值越高。除速效钾外,露天蔬菜的土壤有机质、全氮、有效磷、pH指标值均低于设施菜地。距离城镇越近,土壤有机质、全氮含量和pH越高。两种菜地分布密度与有机质、全氮空间分布呈高高空间正相关,与有效磷和速效钾呈低高空间负相关,与pH在土壤中呈高低空间负相关。研究结果表明,两种菜地土壤属性指标值因受到种植时间与城镇距离因素的影响而差异明显。因经济利益驱动,设施菜地种植时间较短但土壤养分累积较快。菜地分布密度对土壤属性空间分布格局影响明显,菜地种植与土壤酸化、养分累积具有一定的相关性。通过Moran′s I空间分析,可实现对蔬菜生产区域的管理,为进一步分析土壤属性扩散演化机制提供参考。

图解Bootstrap方法用于空间相关性Moran检验的有效性

因为区域间经济收敛、外商直接投资和知识溢出等领域的空间经济计量研究依赖于空间关系的存在,所以进行空间相关性Moran’s I检验是关键。然而,已有空间相关性Moran’s I检验理论受到众多假设条件限制。利用"名义水平—实际水平"图和"名义水平—功效"图,解析非对称Wild Bootstrap方法用于空间相关性Moran’s I检验的有限样本性质,发现即使模型不满足经典的分布假设条件,与渐近检验相比,Bootstrap方法也能够有效地检验研究对象间的空间相关性。

我国省域人口安全水平的现状评价与空间相关性分析——基于GCPA模型和Moran’s I统计量

在建立人口安全水平评价指标体系的基础上,通过运用GPCA模型和基于Moran’s I统计量的全域空间关联的分析方法,对我国31个省域2005～2008年的人口安全水平现状及其空间相关性进行了动态综合评价。结果表明,近年来各地区之间的发展差距虽趋于缩小,但仍存在显著差异,不均衡发展的态势十分突出,且在空间分布上存在显著的自相关现象和集聚效应,省域人口安全状况的演化呈现出高度的空间稳定性。

中国工业环境效率的区域差异及其空间相关性分析——基于SBM—Undesirable模型和Moran's I统计量

本文采用SBM—Undesirable模型测度了中国30个省(市)2000—2010年的工业环境效率,并通过Moran's I统计量对其空间相关性进行了分析测算。结果表明,总体上,2000—2010年全国大部分省(市)工业环境效率值逐年下降;分区域来看,中部、西部和东北部地区工业环境效率普遍较低,且与东部沿海地区存在明显差距;从各省(市)来看,北京、上海、山东、广东、海南、黑龙江等6地区工业环境效率为1,而山西、四川、重庆、内蒙古等4地区工业环境效率均在0.3以下,工业发展与环境关系严重失衡。同时,本文研究也证实了中国各区域工业环境效率的演化呈现出高度的空间稳定性。因此,政府应根据区域间的空间差异性有针对性地制定区域协调发展政策,推进形成跨区域间良好的环境合作机制,才能达到经济发展与环境保护的双赢。

贵州金融产业集聚水平测度与评价——基于区位熵值和Moran’s Ⅰ值分析

金融资源的空间集聚已经成为金融业发展的一种趋势并成为推动区域经济高速发展并显著提升区域竞争力的重要引擎。本文首先对金融集聚概念进行界定并分析金融集聚特征,其次运用熵值法和Moran’sⅠ值分析区域金融集聚水平,再次从全国和西部视角分析贵州金融集聚现状,最后给出结论与相应启示。