基于容积率指数和单要素DEA方法的工业用地利用效率区域差异研究

从土地利用无差异比较的角度出发,在阐释土地利用差异性比较的思路后,构建容积率指数(VRI)分析了不同区域工业用地利用强度变化,并消除工业产业结构对不同区域工业用地面积的影响,在此基础上利用单要素DEA方法分析了全国不同区域工业用地利用效率的特征及变化趋势.研究结果表明:VRI高的区域多分布在东南沿海地区,VRI低的区域多分布在中西部地区,并且东部地区VRI呈下降趋势;工业用地面积修正后,工业用地利用效率增大的区域多集中在中西部地区,工业用地利用效率下降的区域主要出现在东南沿海地区;以长江三角洲和珠江三角洲为主的东南沿海经济发达地区工业用地利用效率明显高于中西部地区;变异系数反映出区域间工业用地利用效率的差异程度正在逐渐缩小,工业产出的不均衡程度大于工业用地配置的不均衡程度.     

碳排放约束下耕地利用效率的区域差异及其影响因素

论文将耕地利用碳排放纳入耕地利用效率的测度框架中,综合运用SBM-Undesirable模型、基尼系数分解模型和Tobit模型对中国大陆31个省区2003—2015年耕地利用效率的差异格局及影响因素进行定量测度。结果表明：1）总体来看,大部分省份考虑碳排放指标后形成的耕地利用效率值与不考虑碳排放指标相比都有不同幅度的下降;2）从SBM模型测度结果来看,不同尺度耕地利用效率在研究期内都呈上升趋势且表现出明显的区域差异,其中,东北地区的年平均耕地利用效率最高,中部地区最低;3）全国和四大区域耕地利用效率的基尼系数都有不同幅度的降低,地区差距有所缓解,组内差异缩小是中国耕地利用效率地区差距缩小的主要来源;4）耕地资源禀赋、经济发展水平、科学技术发展和政府重视程度等是影响耕地利用效率差异的重要因素,但是在不同样本分组情况下,不同因素的影响方向和强度存在差异;5）除了在技术层面探寻耕地利用减排路径及合理规模外,还应该在制度和政策层面对碳排放进行规范和引导,实现耕地低碳、高效利用及社会经济绿色发展。     

北京市食物消费虚拟水含量研究

虚拟水是指在生产商品和服务过程中消耗的水资源数量。人们在消费商品或服务的过程中,即在消费隐含其中的虚拟水。我国是水资源比较匮乏的国家,且水资源在时间和空间上分布不均匀。随着人口和经济的不断增长,我国对水资源的需求也逐渐增加,缺水问题日益严重。水资源短缺已经成为制约我国社会经济发展的关键因素。虚拟水理论为解决水资源危机提供了新的思路。在居民的虚拟水消费中,食物消费中隐含的虚拟水占很大比例,且食物消费与居民生活息息相关。本文以北京市为例,计算了2009年北京市居民食物消费中隐含的虚拟水含量,并对城乡居民和不同收阶层居民的食物虚拟水消费总量及结构进行了对比分析。结果显示,北京市居民食物消费的虚拟水含量在城乡间及城乡各收入阶层间都存在差异,且城乡间及农村各收入阶层间虚拟水消费结构也存在差异。造成这种差异的原因是消费水平及消费结构的不同。     

城乡居民食材消耗的多尺度地域差异及政策启示——基于烟台、兰州、新乡、九江家庭食谱的实证分析

近年中国粮食国际依赖程度持续上升,降低损耗、避免浪费成为解决粮食安全体系韧性问题的重要途径。然而由于不同地域城乡居民的饮食结构明显不同,实施开源节流的食品供应保障政策法规必须重视居民食材消耗的地域差异性,因此基于全球化视角解析居民食材的本地供应比例及其地域差异成为有待补阙的课题。为此,以烟台、兰州、新乡、九江4个城市为例,采用问卷调查的方式,探究4个城市食材消耗和对应生产土地需求量的差异性。结果显示：（1）不同食材与对应消耗的土地资源存在显著的地域差异,且这一差异与城市自然本底和居民饮食习俗密切关联;（2）4个城市居民食谱的全球化、本土化和本地化具有明显区别,虽然不同食材的本地化程度差异相对较小,但全球化程度差异显著。基于分析结果,探讨了粮食安全与反食品浪费的政策建议：一是反食品浪费的政策法规实施,需充分结合居民食材消耗的地域性特征,建立针对性的食材消耗标准与动态监测系统;二是在全球波动、强调粮食安全的背景下,地方政府应结合国土空间规划,讨论城市预留本地食材供应的战略性产地的可能性,以减少运输过程中的损耗。     

Driving restrictions post-stroke: Physicians' compliance with regulations

Objective: Suffering a stroke might lead to permanent cognitive and/or physical impairment. It has been shown that these impairments could have an impact on an individual's fitness to drive. In Sweden, as in many other countries, there are regulations on driving cessation post-stroke. Information on driving cessation should be given to all patients and noted in the journal. The present study sought to determine physician's compliance to driving regulations post-stroke as well as follow-up and gender aspects.

Method: A retrospective study of medical records on stroke patients was carried out. The study covered all of the medical records on stroke incidents (n = 342) during a year at a typical medium to large-sized hospital in Sweden.

Results: A journal entry on driving cessation post-stroke was missing in 81% of the medical records. Only 2% of the patients were scheduled for a follow-up meeting specifically concerning fitness to drive. Significantly more men than women had an entry on driving in the journal.

Conclusions: We conclude that the Swedish regulations on driving cessation post-stroke were not followed at the participating hospital. It is crucial that all stroke patients receive information on driving cessation because their condition might affect fitness to drive. Analysis of follow-up records showed that there was no consistent method for assessment of a patient's fitness to drive. There was also a gender difference in the material, which warrants further investigation.     

准好氧填埋场作业台阶温室气体CO_2的释放通量研究

采用静态箱-气相色谱法测定了河北省某准好氧填埋场作业台阶表面的温室气体CO2释放通量,分析了填埋时期和导气管距离对CO2释放通量的影响。结果表明:导气管附近区域表面的CO2释放量较大,且不同区域的CO2释放通量存在明显差异(最大值和最小值分别278.6和12.5 g/(m2.d);同一区域上午、中午和下午的CO2释放通量差异相对较小,但中午和下午高于上午。同时,填埋4、8、12和16个月区域的CO2平均释放通量分别为56.9,70.0,110.2和47.0 g/(m2.d),即CO2的释放通量随着填埋龄的增加呈现先增加后逐渐降低的趋势,并在填埋12个月达到CO2释放通量的最大值。此外,各填埋区作业台阶表面CO2释放通量随着距离导气管距离的增加呈指数函数递减的趋势。     

Molecular analysis of bacterial community in the tap water with different water ages of a drinking water distribution system

The increase of water ages drove the deterioration of drinking water quality. The relative abundance of Rhizobiales uniquely increase during distributing process. Rhizobiales order was helpful for inhibiting corrosion under high chlorine level. New disinfecting strategies should be developed to ensure drinking water safety. Bacterial community in the drinking water distribution system (DWDS) was regulated by multiple environmental factors, many of which varied as a function of water age. In this study, four water samples with different water ages, including finished water (FW, 0 d) and tap water (TW) [TW1 (1 d), TW2(2 d) and TW3(3 d)], were collected along with the mains of a practical DWDS, and the bacterial community was investigated by high-throughput sequencing technique. Results indicated that the residual chlorine declined with the increase of water age, accompanied by the increase of dissolved organic matter, total bacteria counts and bacterial diversity (Shannon). For bacterial community composition, although Proteobacteria phylum (84.12%-97.6%) and Alphaproteobacteria class (67.42%-93.09%) kept dominate, an evident regular was observed at the order level. In detail, the relative abundance of most of other residual orders increased with different degrees from the start to the end of the DWDS, while a downward trend was uniquely observed in terms of Rhizobiales, who was inferred to be chlorine-resistant and be helpful for inhibiting pipes corrosion. Moreover, some OTUs were found to be closely related with species possessing pathogenicity and chlorine-resistant ability, so it was recommended that the use of agents other than chlorine or agents that can act synergically with chlorine should be developed for drinking water disinfection. This paper revealed bacterial community variations along the mains of the DWDS and the result was helpful for understanding bacterial ecology in the DWDS.     

大兴安岭南部温带山杨天然次生林不同生长阶段生物量及碳储量

基于内蒙古赛罕乌拉森林生态系统定位研究站山杨（Populus davidiana Dode）天然次生林幼龄林、中龄林、近熟林、成熟林及过熟林生物量调查,探讨了不同龄组山杨天然次生林单株木、林分、林下植被和枯落物的生物量及群落碳储量的时空变化规律。结果表明：随林龄的增大,山杨天然次生林木和各器官生物量总体呈增加趋势,树干所占比例增加,中龄林增加尤为明显;林下植被层、枯落物层生物量随林龄增大呈增加趋势。群落总碳储量的空间分布序列是：乔木层〉枯落物层〉林下植被层。幼龄林、中龄林、近熟林、成熟林和过熟林群落的碳储量分别为27.146 6、53.545 1、60.889 8、77.915 8、79.135 3t.hm-2,乔木层碳储量分别为22.206 5、47.215 7、52.056 3、68.445 3、68.773 1 t.hm-2,枯落物层和林下植被层碳储量平均值分别为5.814 4、2.172 7 t.hm-2。乔木层、枯落物层和林下植被层碳储量占总量的平均率分别为86.05%、10.39%和3.57%。研究认为山杨天然次生林群落碳储量随林龄增加的变化规律明显,碳汇潜力巨大;中龄林为碳储量增长迅速期,且持续较长一段时间,是林分管理的关键阶段;自然稀疏有利于促进林木生长,林分碳储量并未随林分密度下降而减小。