Introduction of Relative Abundance Distribution (RAD) Indices, Estimated from the Rank-Frequency Diagrams (RFD), to Assess Changes in Community Diversity

Quantifying a relative abundance distribution based on thesampling of a set of species is a widespread problem in ecology.A number of diversity indices have been proposed and used in numerous works in spite of a lack of statistical characteristics and tests of comparison. The relative abundancedistribution can also be described using rank-frequency diagrams but fitting these diagrams to mathematical models such as the Zipf-Mandelbrot model remains problematic. Strong correlation between the Zipf-Mandelbrot model parameters prevent their estimation by optimization algorithm. In light of this, new indices of sampled communities are introduced here. These indices are two linear regression slopes estimated from rank-frequency diagrams. The numerous statistical studies that have been carried out on linear regression models are used to compare sampled communities. These new indices possesscharacteristic properties with an ecological meaning.Correlations between these indices, the Zipf-Mandelbrot modelparameters and an evenness diversity index are examined. Anecological application is made using entomological data as anexample. This example consists of a transect from the edge of apond to a dry forest along which 60,000 insects were sampledfrom six different sampling stations. Using the new indicesdescribed here, station C, located at the edge of that areasubject to influence from the pond, is differentiated from theother stations. This station would seem to present the lowestdegree of niche diversity and the lowest evenness, and recent observations confirm the deterioration of this station.     

降尘规律研究--兰州城区降尘变化规律及多元自身回归预测

探讨了降尘的年变化、月变化.运用逐步回归筛选变量.采用主分量分析法,得出不同季节的主分量,揭示了降尘的规律,建立了多元自身回归预测方程.对城区降尘进了预测,并与实测作了验证和对比,取得较好效果.     

2030年可持续发展议程对全球及中国环境治理的影响

《2030年可持续发展议程》已经形成了社会、经济与环境三大支柱的格局.根据进程追踪的方法,本文通过回顾环境进入《2030年可持续发展议程》目标的过程,着重分析环境目标未来15年将对全球与中国环境治理产生的重要影响.在全球环境治理层面的基本结论是:①全球环境治理体系的重要性将显著上升.②新型伙伴关系将强化环境非政府组织与市民社会的作用.③未来全球环境治理将形成以数据和指标为驱动的特点.④联合国系统内环境机构的作用将进一步强化,联合国环境署的发展受到关注.⑤环境与气候变化中的资金融资与技术转让渠道将进一步多元化.⑥气候变化问题与其他环境问题将在全球和国家层面深度融合.对中国环境治理的积极影响,体现在:①《2030年可持续发展议程》将为中国经济的转型升级和可持续发展提供新的强大动力,并形成倒逼机制;②将显著提升中国公众的环保意识;③为中国在全球治理中发挥关键性作用提供了难得的着力点;④将使中国的区域合作更加“绿色化”.当然,在新常态的经济形势下,全球可持续发展的环境目标也使得中国环境治理的压力与责任不断增加.同时,《2030年可持续发展议程》也存在一系列问题与不足之处:①目标过多且模糊不清,实现难度大.②当前所罗列的一些目标间可能包含潜在的冲突,需要进一步的研究与论证.③环境目标缺乏量化的标准.尽管如此,就环境目标而言,《2030年可持续发展议程》比千年发展目标更加综合、全面和系统,是当今国际社会应对环境问题集体努力的成果,必须高度重视与研究.     

中国农村绿色发展绩效的空间差异

运用多种DEA模型与Gini准则相结合的方法,采用2003—2012年中国31个省、直辖市和自治区农村数据,对中国及其各地区农村绿色发展绩效值进行了动态测算与分析,在此基础上,对各省市及其所属地区农村绿色发展绩效值进行排名和分析。结果表明,从全国层面来看,中国农村绿色发展绩效整体上呈现上升趋势,如综合绩效值由2.184上升至2.824,表明全国在关注农村经济发展的同时越来越注重环境保护,注重资源和能源的节约,从而促进了全国农村地区绿色发展绩效的提高;从分区域来看,农村绿色发展绩效存在地区差异,绿色发展绩效较高地区是东北,年均值为2.502,西北次之,年均值为2.385,华北、华东和中南地区绩效值相对偏低;进一步地,各省、直辖市和自治区农村绿色发展绩效逐年呈现上升趋势,但有部分省市,如辽宁、河北和山西等,农村绿色发展绩效值偏低,甚至低于该省市所在地区的平均绩效值,这不仅反映了该省市农村绿色发展绩效较低,而且表明了该省市农村绿色发展绩效的高低制约着其所在地区农村整体绿色发展绩效的提升。此外,由于不同省、直辖市和自治区在资源禀赋、技术水平、政策和制度环境等方面不同,农村绿色发展的绩效值在省际之间存在较大差异。基于研究结果,在今后我国农村地区绿色发展过程中,一方面,需要加大绿色资源的投入,为农村绿色发展提供基本的条件;另一方面,需要加大对农村绿色劳动力的投入,确保为农村绿色发展提供高素质劳动力;与此同时,还要不断提高绿色技术水平,为农村绿色发展创造良好的技术条件,以此促进我国农村地区绿色绩效的进一步提高。     

多元回归和BP人工神经网络在预测混合厌氧消化产气量过程中的应用比较

对脂肪类单基质和城市污水厂剩余污泥混合厌氧消化过程的产气阶段进行基于多元回归和BP人工神经网络的产气量预测模型比较研究。实验数据分别取自反应过程的第1～16天和第17～70天。结果表明:多元回归模型的预测平均准确率分别为75.69%和79.29%;BP神经网络模型的预测平均准确率为79.05%。通过对比2种模型的预测结果可知,两种模型都有较高的预测准确率,但BP模型的预测准确率更高,更适用于混合厌氧消化产气量预测。     

Wrong-way driving crashes: A multiple correspondence approach to identify contributing factors

Objective: Wrong-way driving (WWD) crashes result in 1.34 fatalities per fatal crash, whereas for other non-WWD fatal crashes this number drops to 1.10. As such, further in-depth investigation of WWD crashes is necessary. The objective of this study is 2-fold: to identify the characteristics that best describe WWD crashes and to verify the factors associated with WWD occurrence.

Methods: We collected and analyzed 15 years of crash data from the states of Illinois and Alabama. The final data set includes 398 WWD crashes. The rarity of WWD events and the consequently small sample size of the crash database significantly influence the application of conventional log-linear models in analyzing the data, because they use maximum-likelihood estimation. To overcome this issue, in this study, we employ multiple correspondence analysis (MCA) to define the structure of the crash data set and identify the significant contributing factors to WWD crashes on freeways.

Results: The results of the present study specify various factors that characterize and influence the probability of WWD crashes and can thus lead to the development of several safety countermeasures and recommendations. According to the obtained results, factors such as driver age, driver condition, roadway surface conditions, and lighting conditions were among the most significant contributors to WWD crashes.

Conclusions: Despite many other methods that identify only the contributing factors, this method can identify possible associations between various contributing factors. This is an inherent advantage of the MCA method, which can provide a major opportunity for state departments of transportation (DOTs) to select safety countermeasures that are associated with multiple safety benefits.     

The perception of Malaysian pedestrians toward the use of footbridges

Objective: The footbridge is a vital structure in the road network and a cornerstone among crossing facilities. Yet, it suffers from low usage by pedestrians as they try to cross the street on the level. This study aims to analyze the perceptions of Malaysian pedestrians toward the use of footbridges with the consideration of different factors.

Method: The study was carried out by collecting data from field observation and questionnaire distribution on the street among the public. The data were statistically analyzed by applying multiple linear regression models and a series of chi-square tests.

Results: The study found that the most influential factor cited by pedestrians in decision making regarding using a footbridge is the existence of an escalator. Being in a hurry and the fear of heights were significantly associated with choosing not to use a footbridge. Zebra crossing was chosen as the most favorable type of crossing facility by the majority of respondents. In addition, installation of a fence and barriers was proposed as an effective procedure to prevent jaywalking. To construct new and efficient footbridges in the future, the study suggests consideration of traffic volume, posted speed limit, and the number of lanes, because these are the most influential factors to predict the usage rate.

Conclusions: The study encourages decision makers and stakeholders to consider providing escalators for new footbridges to enhance the safety of pedestrians.     

石羊河流域多情景土地利用优化及碳储量评估

研究碳储量与土地利用变化的响应关系及空间分布特征,预测未来土地利用类型变化所导致的碳储量变化趋势,可为流域政策制定、土地利用结构调整和“双碳”目标的实现提供一定的借鉴. 基于2000年、2010年和2020年三期土地利用数据,运用InVEST模型和PLUS模型,开展石羊河流域2000~2020年间和2030年自然发展、城镇发展和生态保护这3种情景下土地利用变化及其对碳储量的影响研究. 研究发现：①2000~2020年石羊河流域主要土地利用类型是耕地、草地和未利用地,且耕地、水域和建设用地的面积呈增加趋势,其中建设用地面积增幅最大. ②较2020年,2030年自然发展情景下,耕地、水域和建设用地面积均有所增加,分别增加6.15%、9.56%和29.9%;在城镇发展情景下,建设用地面积增加最多;相比其他两种情景,在生态保护情景下林地和草地面积出现了增加. ③石羊河流域2000~2020年碳储量呈平稳增加的趋势,20年间增加了0.035×10⁸ t,主要源于耕地面积的增加. ④2030年自然发展、城镇发展和生态保护3种情景下石羊河流域的碳储量分别为5.65×10⁸、5.64×10⁸和5.73×10⁸ t,较2020年均有增加,其中生态保护情景下碳储量增加最多,主要是源于草地和林地面积的增加. 研究结果表明建设用地的扩张是造成碳储量流失的主要原因,若采取有效的生态保护措施将有助提高流域碳储量,可以解决由于经济发展而导致的碳储量流失问题.     

基于多元统计分析的火灾灾后抢险物资配送模型研究

传统物资配送方法存在配送物资效率低、配送成本高等缺点,为了及时确定抢险物资应急救援路线,向火灾受灾点快速配送抢险物资,提出基于多元统计分析的火灾灾后抢险物资配送模型。建模时采用多元统计分析法分析火灾受灾点救援需求和配送路线连通随机性,以及救援出发点对受灾点的最大覆盖范围的限制,利用加权贝叶斯算法将物资配送多目标规划问题转变成单目标规划问题,建立抢险物资配送单目标规划模型;运用遗传算法对模型求解,并采用惩罚函数处理模型中的约束条件,实现物资在受灾点之间均衡分配。     

Development of indirect competitive fluorescence immunoassay for 2,2′,4,4′-tetrabromodiphenyl ether using DNA/dye conjugate as antibody multiple labels

An indirect competitive fluorescence immunoassay using a DNA/dye conjugate as antibody multiple labels was developed on 96-well plates for the identification and quantification of 2,2′,4,4′-tetrabromodiphenyl ether (BDE-47) in aqueous samples. A hapten, 2,4,2′-tribromodiphenyl ether-4′-aldehyde, was synthesized, and was conjugated to bovine serum albumin to form a coating antigen. Specific recognition of the antigen by anti-PBDE antiserum was confirmed by a surface plasmon resonance measurement. In the immunoassay, the coating antigen was adsorbed on a 96-well plate first, and a sample, antiserum and biotinylated goat anti-rabbit secondary antibody were then added and reacted sequentially. A biotinylated, double-stranded DNA with 219 base pairs was attached to the secondary antibody by using streptavidin as a molecular bridge. In situ multiple labeling of the antibody was accomplished after addition of a DNA-binding fluorescent dye, SYBR Green I. The working range of the immunoassay for the BDE-47 standard was 3.1-390 μg/L, with an IC₅₀ value of 15.6 μg/L. The calculated LOD of the immunoassay is 0.73 μg/L. The immunoassay demonstrated relatively high selectivity for BDE-47, showing very low cross-reactivity (< 3%) with BDE-15, BDE-153 and BDE-209. With a spiked river water sample containing 50 μup g/L BDE-47, quantification by the immunoassay was 41.9 μg/L, which compared well with the standard GC-ECD method (45.7 μg/L). The developed immunoassay provides a rapid screening tool for polybrominated diphenyl ethers in environmental samples.