碳市场对能源结构低碳转型的影响及作用路径

选取中国2000～2018年30个省市的面板数据,构建了能源消费结构低碳化指数,基于多期双重差分、三重差分等方法实证检验碳交易政策与能源消费结构低碳转型之间的关系及异质性影响,并进一步利用多重中介效应模型探讨碳交易政策推动地区能源消费结构低碳转型的作用路径.结果表明:碳交易政策可以显著提升地区能源消费结构低碳化水平且作用效果逐年增强.从作用路径看,“四大效应”激励作用彰显,作用效果由大到小依次为结构优化效应、行为驱动效应、生态创新效应和环保支出效应;从异质性影响看,GDP增速较慢地区的政策实施加快了能源消费结构低碳转型,影响明显高于GDP增速较快地区;碳交易政策对东部地区的正向推动效应显著,对中西部地区无明显促进作用.     

垃圾按量收费政策效应的实证研究

垃圾按量收费是管制城市垃圾的最直接的环境经济政策。它根据垃圾排放量向居民征收（不同的）费用。从而实现有效率的资源配置。本文通过对城市居民的问卷调查．采用描述性统计分析、方差分析、回归分析等方法。对垃圾按量收费的政策效应进行实证研究。以期为中国垃圾按量收费政策的制定和实施提供借鉴。我们的研究旨在解决两个问题：一是测度垃圾按量收费政策的总体效应;二是考察垃圾按量收费政策对不同居民的效应差异。结果表明。从总体上看．超过半数的居民认为垃圾按量收费更合理,但多数人还是更喜欢每月固定收费;从对不同居民的具体分析看,中高收入者倾向认为垃圾按量收费更合理,年长者更喜欢每月固定收费。实行垃圾按量收费后．年轻者更可能减少倒垃圾的量．但也更可能偷偷倒垃圾。     

小麦异源细胞质遗传效应的比较研究

本文以稳定的同核异质异核杂种小麦为材料,对小麦属和山羊草属的细胞质遗传效应进行了比较研究,分析了异源细胞质遗传疚的特点,并初步筛选出了一批在小麦雄性不育性应用中以及在小麦核质杂种优势利用中有价值的细胞质材料。     

Behavior of the organophosphorus insecticide fenitrothion in stored faba beans and its biological effects towards experimental animals

Sound whole-seed faba beans were treated with (methyl-¹⁴C) fenitrothion [O, O-dimethyl-O-(3-methyl-4-nitrophenyl) phosphorothioate] at 5 and 10 mg insecticide/kg seeds, a dose normally used in practice. During the 30 weeks of storage period, the penetration and distribution of insecticide residues were studied. The amount of surface residues, internal residues and bound insecticide residues was estimated. Surface residues were found to decrease with the increase in time of storage, whereas internal residues showed a gradual increase with time apparently not dose dependent. Grain-bound residues increased with time and reached to its maximum (14–18%) after 24 weeks of storage. Chromatographic analysis of the internal extracts revealed the presence of the parent compound together with three main metabolites which were found in both free and conjugated form. Feeding mice for 90 days with a diet mixed with total internal fenitrothion residues in stored faba beans led to a reduction in body weight gain, and an appreciable decrease in cholinesterase activity of 32% for plasma and 15% for red blood cells (RBC_S) after two months of experiment. Also, a significant decrease was showed in both total protein and albumin concentration at the end of feeding period (90 days). Liver and kidney function, as well as lipid profile of treated mice significantly increased at the end of feeding period. After a one-month recovery period, all the examined blood parameters returned to about the control values except blood urea and serum triglyceride.     

The effects of ammonium sulphate and urea upon egg hatching and miracidial survival of Schistosoma mansoni

Abstract

The effects of various concentrations of ammonium sulphate and urea on egg hatching and miracidial survival of S. mansoni were tested in order to determine if the use of these fertilizers in the ricelands of the Republic of Cameroon could affect the transmission of schistosomiasis. Results indicate that hatching of eggs and survival of miracidia varied with concentrations of tested chemicals and times of exposure. Exposure of S. mansoni eggs to 0.20%‐1.00% ammonium sulphate or to 0.50%‐4.00% urea reduced their ability to hatch and produce miracidia. A chemical concentration of 1.00% ammonium sulphate or 4.00% urea was found to be sufficient to produce complete inhibition of hatching. High concentrations of both chemicals not only inhibited miracidial emmergence but also may be ovocidal. Results obtained from miracidial survival tests indicated that LC₅, LC₅₀ and LC₉₅ values for ammonium sulphate were 0.07%, 0.80% and 10.61% after 2 hours of exposure; 0.03%, 0.16% and 0.90% after 4 hours of exposure; and 0.30%, 0.20% and 0.40% after 6 hours of exposure respectively. Similar statistical analyses revealed that the LC₅, LC₅₀ and LC₉₅ values for urea were 0.22%, 1.90% and 16.25% after 2 hours of exposure; 0.28%, 0.57% and 1.14% after 4 hours of exposure; and 0.13%, 0.27% and 0.57%” after 6 hours of exposure respectively. Although the two fertilizers exerted some adverse effects on S. mansoni eggs and miracidia at relatively high concentrations, neither of them was found to be of practical value. Ammonium sulphate and urea concentrations effective in killing S. mansoni eggs and miracidia were about one to two orders of magnitude greater than the actual field application rates.     

Investigation of hit-and-run crash occurrence and severity using real-time loop detector data and hierarchical Bayesian binary logit model with random effects

Objective: Most of the extensive research dedicated to identifying the influential factors of hit-and-run (HR) crashes has utilized typical maximum likelihood estimation binary logit models, and none have employed real-time traffic data. To fill this gap, this study focused on investigating factors contributing to HR crashes, as well as the severity levels of HR.

Methods: This study analyzed 4-year crash and real-time loop detector data by employing hierarchical Bayesian models with random effects within a sequential logit structure. In addition to evaluation of the impact of random effects on model fitness and complexity, the prediction capability of the models was examined. Stepwise incremental sensitivity and specificity were calculated and receiver operating characteristic (ROC) curves were utilized to graphically illustrate the predictive performance of the model.

Results: Among the real-time flow variables, the average occupancy and speed from the upstream detector were observed to be positively correlated with HR crash possibility. The average upstream speed and speed difference between upstream and downstream speeds were correlated with the occurrence of severe HR crashes. In addition to real-time factors, other variables found influential for HR and severe HR crashes were length of segment, adverse weather conditions, dark lighting conditions with malfunctioning street lights, driving under the influence of alcohol, width of inner shoulder, and nighttime.

Conclusions: This study suggests the potential traffic conditions of HR and severe HR occurrence, which refer to relatively congested upstream traffic conditions with high upstream speed and significant speed deviations on long segments. The above findings suggest that traffic enforcement should be directed toward mitigating risky driving under the aforementioned traffic conditions. Moreover, enforcement agencies may employ alcohol checkpoints to counter driving under the influence (DUI) at night. With regard to engineering improvements, wider inner shoulders may be constructed to potentially reduce HR cases and street lights should be installed and maintained in working condition to make roads less prone to such crashes.     

湖沼型血吸虫病疫区钉螺空间自相关的样点尺寸效应

钉螺是血吸虫的唯一中间宿主,与众多地理因子一样,钉螺的空间自相关具有明显的尺度效应。在湖沼型血吸虫病疫区典型洲垸型草洲选择一块50 m×50 m的试验样地,采用推扫式全覆盖方法进行了钉螺普查。用全局空间自相关Moran I指数、局部空间自相关Moran散点图和局部Moran’s I指数,进行了钉螺分布空间自相关的样点尺寸效应研究。结果表明:所有样点尺寸钉螺数目的全局Moran’s I均为极显著空间正相关(P0.001);不同样点尺寸下的钉螺样点在局部自相关Moran散点图上绝大多数集中分布在象限1和象限3内,表明试验样地的钉螺呈空间聚集分布;钉螺样点尺寸越小,用局部Moran’s I指数对单个钉螺样点附近的空间自相关表现得越细微,表明全局Moran’s I指标会掩盖实际存在的局部空间自相关与全局不一致的现象。     

青山湖流域景观格局对河流氮磷营养盐影响的时空尺度效应

景观格局对水质的影响具有时空尺度依赖性,然而不同空间尺度下景观组成、景观配置及景观坡度对季节性水质的影响程度仍然不甚明了. 基于青山湖流域26个监测点的总氮、总磷、硝态氮和铵态氮数据,采用景观格局分析、冗余分析和偏冗余分析方法定量景观格局对河流氮磷营养盐影响的时空尺度效应. 结果表明：①子流域尺度内景观格局对河流氮磷浓度的解释力比在缓冲区尺度上高6.8%~8.4%,且这种作用在干季更明显. ②在子流域尺度,林地占比和居民地的散布分裂程度对河流氮磷浓度影响较大;而缓冲区尺度上,农田和居民地分布的坡度以及林地斑块的聚集度是影响氮磷浓度的关键因子. ③景观配置对河流氮磷浓度变化的独立贡献率（20.1%~36.5%）高于景观组成（4.1%~14.5%）和景观坡度（5.5%~23.7%）的独立贡献率,且景观配置对河流氮磷浓度影响随季节变化的敏感度最高,而景观坡度对河流氮磷浓度影响具有更高的空间尺度敏感性. 因此,通过景观格局调控非点源污染应从多尺度角度考虑. 研究结果可从宏观上为制定以非点源污染控制为目标的景观格局优化措施提供科学依据.     

我国淡水水体中双酚A(BPA)的生态风险评价

双酚A(BPA)对水生生物有多种毒性效应,其中雌激素作用尤为显著.本研究依据BPA对水生生物是否有雌激素效应,把数据分为两类,并通过商值法、安全阈值法、商值概率法以及联合概率曲线法评价了我国淡水水体中BPA对水生生物的风险程度.结果表明,采用4种评价方法得出的结果相近,我国淡水生物对BPA的雌激素效应较BPA对水生生物的其他毒性作用更为敏感;安全阈值法较商值法、商值概率法、联合概率风险评价法误差较小,评价结果更为可信.用安全阈值法评价结果表明,以BPA的雌激素作用为效应终点时,水生生物长期暴露于我国淡水环境中,我国64.70%的淡水水体有导致超过5%的水生生物受到雌激素作用的风险,BPA安全浓度上限为15.72 ng·L-1;而水生物种短期暴露于我国淡水环境中,我国20.43%的淡水水体有导致超过5%的我国淡水生物受BPA雌激素作用的干扰,此时BPA安全浓度上限为2.24×102ng·L-1.     

一种新型环境污染物：羟基化多溴联苯醚（OH-PBDEs）

近年来羟基化多溴联苯醚（OH—PBDEs）在诸多环境介质中陆续被检出,其中一些被证明能在生物体内蓄积,另外一些被证明能产生致毒效应．作为一种新型的有机污染物,OH—PBDEs逐渐成为环境工作者研究的新热点．本文介绍了OH-PBDEs在环境中的来源及暴露水平,概述了国内外最近几年关于OH-PBDEs的环境浓度检测、生物体...