手机定位人口数据在应急救援中的应用

随着智能手机的普及,基于手机定位的人口数据在突发性灾害应急救援领域发挥着日益重要的作用。以近几年地震灾区为主要研究对象,选择灾区中有代表性的旅游景区、县城及乡镇,获取这些区域手机定位的人口数据,同时采用传统方法估算区域内人口数量,并进行差异性对比。研究结果表明:差异性最大的是旅游景区、其次是县城和乡镇;在人口年度变化上,旅游景区的人口在7、8月份达到高峰,乡镇人口高值区出现在2月份,县城人口年度差异无明显规律。     

Temporal trends in agricultural water use and the relationships to hydroclimatic factors in the High Plains aquifer region

The High Plains aquifer (HPA) is the primary water source for agricultural irrigation in the US Great Plains. The water levels in many locations of the aquifer have declined steadily over the past several decades because the rate of water withdrawals exceeds recharge, which has been a serious concern to the water resources management in the region. We evaluated temporal trends and variations in agricultural water use and hydroclimatic variables including precipitation, air temperature, reference evapotranspiration, runoff, groundwater level, and terrestrial water storage across the HPA region for different periods from 1985 to 2020 at the grid, county, or region scale. The results showed that water withdrawals decreased from 21.3 km³/year in 1985 to 18.2 km³/year in 2015, while irrigated croplands increased from 71,928 km² in 1985 to 78,464 km² in 2015 in the entire HPA. The hydroclimatic time-series showed wetting trends in most of the northern HPA, but drying and warming trends in the southern region from 1985 to 2020. The groundwater level time-series indicated flat trends in the north, but significant declining in the central and southern HPA. Trends in irrigation water withdrawals and irrigation area across the HPA were controlled by the advancement of irrigation systems and technologies and the management of sustainable water use, but also were affected by dynamical changes in the hydroclimatic conditions.     

Health risk assessment of heavy metals in Cyprinus carpio (Cyprinidae) from the upper Mekong River

The purposes of this research are to quantify the concentration of heavy metals (Zn, Cu, As, Pb, Cd, and Hg) in the water and fish tissues of common carp (Cyprinus carpio) in the upper Mekong River and to thereby elucidate the potential dietary health risks from fish consumption of local residents. Surface water and fish tissues (gill, muscle, liver, and intestine) from four representative sample areas (influence by a cascade of four dams) along the river were analyzed for heavy metal concentrations. Results revealed that the levels of heavy metals in fish were tissue-dependent. The highest Cu and As levels were found in the liver; the highest Zn and Pb levels occurred in the intestine, and the highest Hg level was found in the muscle. The total target hazard quotient (THQ) value for residents is > 1 for long-term fish consumption, and local residents are, therefore, exposed to a significant health risk. Results from the current study provide an overall understanding of the spatial and tissue distribution of heavy metals in water and fish body along the upper Mekong River under the influence of cascade dams and highlight the potential health risk of As for the local residents of long-term fish consumption.

     

Characteristics analysis of near-field and far-field aerodynamic noise around high-speed railway bridge

Environmental Science and Pollution Research - The aerodynamic noise around the high-speed railway bridge is studied by the train-bridge-flow field numerical model and theory analysis. With the...     

有机肥处理对旱地红壤细菌群落及玉米生产力的影响

为探明旱地红壤细菌群落特征及玉米生产力对不同有机肥处理的响应，基于自2002年设置在中国科学院鹰潭红壤生态实验站的有机培肥长期定位试验，采用Illumina高通量测序，研究不同有机肥（不施肥，M0；低量有机肥，M1；高量有机肥，M2；高量有机肥加石灰，M3）处理下土壤细菌群落多样性和结构以及玉米生产力的变化.结果发现，与M0相比，土壤pH、有机质（SOM）、全氮（TN）、全磷（TP）含量和玉米生产力在不同有机肥（M1、M2和M3）处理下均显著增加，其中M3处理的提升效果最佳.施用有机肥显著提高了土壤细菌群落的Shannon、Evenness、Chao1与ACE指数，重塑了细菌群落结构.基于随机森林模型分析，土壤性质中的pH和TP显著影响土壤细菌多样性，而pH、SOM、TP和TN对土壤细菌群落结构影响显著.相关性分析和结构方程模型分析表明，土壤TP和SOM可以通过改变土壤细菌多样性和群落组成间接影响玉米生产力.研究结果从指导我国南方红壤区农田合理施肥的角度，为农田土壤质量提高及耕地产能提升提供科学依据.     

固相萃取-气相色谱法测定水中硝基氯苯类化合物

建立固相萃取-气相色谱法测定水中15种硝基氯苯类化合物的方法。选用HLB柱为固相萃取柱,选用环己烷∶丙酮(3∶1,V∶V)混合溶剂作洗脱剂,得到方法检出限为0.011～0.040μg/L。空白水样加标回收率为73.6%～119%,相对标准偏差为6.1%～13.9%,精密度和准确度良好。对成分不复杂的实际水样进行测定,加标回收率为64.1%～118%,相对标准偏差为5.8%～15.6%,该方法能够基本满足成分不复杂的环境水体中痕量硝基氯苯类化合物的测定。     

饮用水中三卤甲烷的生成机理与影响因素研究进展

在饮用水消毒过程中,氯会与天然有机物(NOM)等反应生成消毒副产物(DBPs),三卤甲烷(THMs)是一种主要的DBPs,长期低浓度的THMs暴露对人体有一定的健康风险。THMs和其前驱物种类繁多、生成机理复杂且影响因素诸多,如何抑制消毒过程中THMs的形成是饮用水安全领域的研究热点。通过查阅大量文献,从THMs形成机理及影响因素等方面归纳了目前THMs研究现状,总结了甲基酮、腐殖酸、氨基酸、β-二酮等重要前驱物生成THMs的反应途径,探讨了操作条件以及离子对THMs生成的影响,对该领域未来研究方向进行了展望。     

基于有序Logit与Probit模型的交通事故严重性影响因素分析

为准确分析影响交通事故严重性的各项因素,引入有序选择模型中的Ordinal Logit模型和Ordinal Probit模型,研究驾驶员、车辆、环境、管理因素与事故严重程度之间的耦合关系,利用计量经济学理论和统计学方法对模型进行显著性检验。并选择美国北卡罗来纳州2010年至2014年385个翻车事故样本进行严重性影响因素分析,所得回归模型参数估计均符合Wald检验(p≤0.0001)和似然比检验(p≤0.0001),模型的拟合度也都符合Pearson检验(p=0.7976)、偏差检验(p=0.6006)和信息准则检验,模型预测精度指标值均大于0.7。所得两个模型中变量"安全带"(p≤0.001)、"路面状况"(p=0.0071)、"道路线形"(p=0.0077)、"路面类型"(p=0.0251)都对翻车事故的严重性具有显著影响,表明有序Logit模型和有序Probit模型均适用于分析和揭示影响交通事故严重性的各个因素。     

Robust Regression with Data-Dependent Regularization Parameters and Autoregressive Temporal Correlations

We introduce robust procedures for analyzing water quality data collected over time. One challenging task in analyzing such data is how to achieve robustness in presence of outliers while maintaining high estimation efficiency so that we can draw valid conclusions and provide useful advices in water management. The robust approach requires specification of a loss function such as the Huber, Tukey’s bisquare and the exponential loss function, and an associated tuning parameter determining the extent of robustness needed. High robustness is at the cost of efficiency loss in parameter loss. To this end, we propose a data-driven method which leads to more efficient parameter estimation. This data-dependent approach allows us to choose a regularization (tuning) parameter that depends on the proportion of “outliers” in the data so that estimation efficiency is maximized. We illustrate the proposed methods using a study on ammonium nitrogen concentrations from two sites in the Huaihe River in China, where the interest is in quantifying the trend in the most recent years while accounting for possible temporal correlations and “irregular” observations in earlier years.     

典型有机磷酸酯阻燃剂分析方法研究进展

有机磷酸酯(OPEs)是一类重要的有机磷阻燃剂,近些年逐渐取代了溴代阻燃剂,广泛应用于各行各业,也因此导致在多种环境介质中有较高的暴露量和潜在风险。已有研究表明,OPEs具有一定的毒理效应,对人体及其他生物均有潜在危害。本文综述了近年来国内外OPEs的检测技术,详述了不同环境介质OPEs的前处理方法。结果表明,目前固相萃取(SPE)和固相微萃取(SPME)仍是水样前处理的主要方法;对于固体样品,加速溶剂萃取/加压液相萃取(ASE/PLE)和微波辅助萃取(MAE)应用较多;虽然大气样品仍以固体吸附剂方式为主,但已向在线一体化方向发展;而生物样品的前处理方法多与水样和固体样品方法相似;但是对于复杂环境介质中OPEs样品的前处理较为困难,方法有待改善;气相色谱-质谱联用(GC-MS)和气相色谱-氮磷检测器(GC-NPD)对弱极性和易挥发的OPEs分析效果好,而强极性和难挥发的OPEs多用液相色谱-质谱联用(LCMS);气相色谱-质谱串联(GC-MS/MS)、液相色谱-质谱串联(LC-MS/MS)和高效液相色谱-质谱串联(UPLC-MS/MS)等对多种复杂的环境介质中的OPEs均有较好的检测分析效果,但并未普及。最后,对OPEs分析测试方法的发展趋势提出了展望。