福建省行业碳排放驱动因素分解及其与经济增长脱钩关系

主要部门和重点行业的二氧化碳排放是区域碳排放的主要来源。厘清行业碳排放影响因素,分析其与区域经济增长相互关系及程度,从而推动部门和行业碳减排对于落实区域碳排放总量控制具有重要意义。本研究运用对数平均迪式指数分解法(LMDI)和Tapio脱钩模型对福建省1997—2017年13个主要碳排放行业进行碳排放驱动因素分解和脱钩分析。结果表明: 电力、热力的生产和供应业是福建省主要的碳排放行业,1997—2017年,其碳排放总量由18.89 Mt上升到120.63 Mt,增长量为101.74 Mt。有色金属冶炼及压延加工业、纺织业、黑色金属冶炼及压延加工业的碳排放增长速度最快,其年均增长率分别为18.1%、12.1%、12.1%。13个主要行业碳排放变动的驱动因素中,经济增长效应和人口规模效应是主要的正向驱动因素,能源结构效应、能源强度效应和产业结构效应的抑制作用在不断增强。从脱钩关系来看,13个主要碳排放行业的脱钩指数整体呈下降趋势。从“十一五”时期开始,部分行业开始出现不同程度的强脱钩。而在“十三五”时期,农、林、牧、渔、水利业表现为扩张负脱钩,电力、热力的生产和供应业表现为弱负脱钩。能源结构效应和能源强度效应对各行业实现脱钩的影响较大,产业结构效应的脱钩努力较小,人口规模效应未做出脱钩努力。     

基于投入产出表的北京市产业生态效率

提高生态效率对协调经济发展与环境保护的关系至关重要。为了了解北京市产业转型过程中各产业部门生态效率的变化趋势,识别提高影响北京市产业生态效率的关键部门,基于北京市投入产出表,运用指标体系法,选取水资源效率,以及废水、二氧化硫、工业固体废弃物的环境效率作为生态效率的衡量指标,核算了北京市2007、2010和2012年各部门的水资源效率以及2005、2007和2010年各部门的环境效率,并比较分析了各部门的水资源的完全用水系数以及污染物的完全排放系数,计算各部门之间完全排放量的相互贡献比例,识别了提高生态效率的关键部门。研究结果:(1)2007—2012年,北京市各部门水资源效率和2005—2010年废水、二氧化硫(SO_2)、工业固体废弃物的环境效率整体呈波动上升趋势。(2)农林牧渔业和废品废料部门是提高水资源效率的关键部门。(3)水的生产和供应业、化学工业、食品制造及烟草加工业、纺织业和造纸印刷及文教体育用品制造业是提高废水环境效率的关键部门。(4)石油加工、炼焦及核燃料加工业、非金属矿物制品业、金属冶炼及压延加工业、电力及热力的生产和供应业是提高SO_2环境效率的关键部门。(5)煤炭开采和洗选业、金属矿采选业、木材加工及家具制造业、非金属矿物制品业、金属冶炼及压延加工业、电力及热力的生产和供应业、水的生产和供应业是提高工业固体废弃物环境效率的关键部门。     

北京市水足迹及农业用水结构变化特征

运用水足迹的理论和方法计算评价了1990—2005年北京市水足迹及水资源利用的可持续性,在此基础上进一步分析了北京市农业用水结构的变化特征。结果表明:(1)北京市水足迹从1990年的81.5亿m3上升至2005年的168.6亿m3,人均水足迹由750.1m3上升为1096.0m3;(2)北京市水资源匮乏度不断升高,1995年以来水资源自给率呈下降趋势,与之相对应的水资源依赖度越来越高;(3)农业部门用水量在本地用水量中的比例平均每年为55.1%,虚拟水净输入量在虚拟水净输入总量中的比例平均每年达到89.1%;(4)高耗水型作物产品生产用水比例升高加大了农业用水压力,动物产品生产用水量呈增加趋势,2001—2005年动物产品生产引入的虚拟水占到其虚拟水总量的81.3%。北京市水资源利用呈不可持续状态,通过农业系统内部结构的优化调整,实现农业部门水资源的高效利用是缓解北京市水资源紧缺问题的关键。     

青海省海西州不同产业结构用水特征分析

水资源严重制约着经济的发展水平, 通过收集整理海西州2005—2018年农业、畜牧业、工业发展和水资源的相关数据, 构建合理指标, 应用冗余分析、变差分析分析了海西州不同产业结构的用水特征, 通过典范对应分析和耦合协调度模型分析了海西州农业发展的主要影响因素和发展状况。结果表明, 海西州工业用水主要依赖于地下供水; 农业、畜牧业和生态用水主要依赖于地表供水。在2005—2018年, 海西州农业发展的主要依赖因素由灌溉用水量和拖拉机数量转变为地表水储量; 海西州农作物播种面积与解释变量(水资源、农业机械数量和从业人数)的耦合关系大致可分为三个阶段, 分别是2005—2008年的未发展阶段, 2009—2014年的不稳定发展阶段和2015—2018年的稳步发展阶段。典范对应分析和耦合协调度模型得到了相似的结果。研究结果可为柴达木盆地水资源管理和经济结构调整提供定量支持。     

基于模糊综合评判的山东省水资源承载力评价

水资源承载力是社会经济稳定发展所能支撑的最大可利用的水资源。在对山东省水资源现状进行调查和统计的基础上, 选取人均水资源量、水资源利用率、供水模数、降雨量, 人均 GDP、人口密度、人均生活用水量、万元 GDP 用水量、万元工业产值用水量、万元农业产值用水量, 耕地灌溉率、生态环境用水率、森林覆盖率共 13 个主要影响区域水资源承载力的因素作为评价因子, 应用模糊综合评判模型对山东水资源承载力现状进行评价。结果表明: 山东省水资源综合评价结果 a 值在 2001-2009 年间低于 0.6, 2010-2015 年间高于 0.6, 表明山东省水资源承载力总体得到了提高; 另外 2001-2015 年间, 大部分年份的 a 值小于 0.6, 个别年份低于 0.4, 年际变化相对较大, 可见山东省水资源承载力水平总体较弱, 年际变化较大。     

京津冀城市群用水效率及其与城市化水平的关系

深入分析京津冀城市群用水效率与城市化水平的相互关系,揭示不同城市城市化水平对水资源利用效率的影响,有助于缓解水资源短缺问题。结合超效率数据包络模型,定量分析了京津冀城市群不同行业的用水效率,从人口、经济、社会与土地等不同城市化角度,全面分析了城市发展水平与生活、工业、农业三大行业用水效率之间的相互关系。主要结论为:(1)2006—2015年,京津冀城市群生活和工业用水效率总体上略微下降,而农业用水效率明显上升;不同城市之间存在明显差别,唐山、衡水与沧州市各行业用水效率均较高,邯郸和邢台市各行业用水效率均偏低。(2)城市发展水平对不同行业用水效率的影响存在明显差异。城市化水平的提升可以显著提高生活用水效率,但对工业和农业用水效率具有不同程度的负向影响。综合用水效率仅受到经济城市化的显著影响,相关系数达0.19,表明提高用水效率的关键是进一步调整经济产业结构。(3)城市化水平与用水效率梯度的匹配状态较差。一方面,京津冀13个城市中达到匹配的城市仅有4个,占京津冀城市总数的30.77%,匹配程度较低。另一方面,不存在城市化水平和用水效率双高型的城市,匹配层次较低。综上所述,针对京津冀城市化发展与用水效率的失衡关系,应审视水资源投入产出结构并尝试行业联动等节水发展模式。     

新疆区域水资源对产业生态系统与经济增长的动态关联——基于VAR模型

新疆正面临"五化同步"对水资源的需求不断增长与水资源开发利用过度的矛盾。水资源瓶颈制约已成为影响新疆经济可持续发展和长治久安的突出问题之一。运用VAR模型,通过ADF检验、脉冲响应函数和方差贡献度分解,对2000—2014年新疆耗水产业生态系统和经济增长的长期均衡关系进行实证分析。结果表明:(1)经济增长与总用水量、工业用水量和农业用水量之间均存在长期均衡关系;(2)经济发展对用水量产生负向冲击,工业用水量和农业用水量随着经济发展出现正向冲击效应。(3)新疆经济快速增长伴随着水资源的大力开发和过度利用。据此提出对策建议,通过实施严格的退地减水政策,明确用水总量控制和定额指标,加强跨流域调水工程建设,防止浪费等多途径维持新疆水资源可持续利用和耗水产业健康发展。     

基于VAR模型的新疆区域水资源对产业生态系统与经济增长的动态关联性研究

新疆正面临“五化同步”对水资源的需求不断增长与水资源开发利用过度的矛盾。水资源瓶颈制约已成为影响新疆经济可持续发展和长治久安的突出问题之一。运用VAR模型,通过ADF检验、脉冲响应函数和方差贡献度分解,对2000—2014年新疆耗水产业生态系统和经济增长的长期均衡关系进行实证分析。研究结果表明:(1)经济增长与总用水量、工业用水量和农业用水量之间均存在长期均衡关系;(2)经济发展对用水量产生负向冲击,工业用水量和农业用水量随着经济发展出现正向冲击效应。(3)新疆经济快速增长伴随着水资源的大力开发和过度利用。据此提出对策建议,通过实施严格的退地减水政策,明确用水总量控制和定额指标,加强跨流域调水工程建设,防止浪费等多途径维持新疆水资源可持续利用和耗水产业健康发展。     

中国生态地理区城市水资源利用效率及影响因素

水资源利用效率是落实最严水资源管理制度和水生态文明建设的重要内容,是中国国民经济社会发展的重要战略问题。通过分类数据包络分析模型对2007-2016年中国生态地理区城市水资源利用效率进行测算,分析全国和生态地理区城市水资源利用效率特征,采用Tobit回归模型探讨中国和生态地理区城市用水效率的影响因素。研究结果表明：我国城市水资源利用效率普遍较低,全国水资源效率均值呈现先下降后上升波动式发展,全国城市间用水效率差距在缩小。生态地理区水资源利用效率差异显著,温带干旱区、温带半干旱区、温带半湿润区、温带湿润区和亚热带湿润区用水效率依次递减,区域间水资源效率差异在逐渐减小。城市人口、土地利用结构、经济发展水平、产业结构与全国城市水资源利用效率呈显著正相关,而城市供水、用水结构、水资源管理政策则表现为显著负相关性。     

锦界生态工业园水资源系统动力学仿真与调控

如何合理开发利用水资源,保护区域生态环境,实现人与自然的和谐发展,是当今世界所面临的共同问题.以陕北锦界生态工业园水资源系统为例,在分析系统结构的基础上,构建了水资源系统动力学模型,确定水技术进步因子、水资源循环利用率、污水处理投资率、万元产值年耗水量、日人均用水量为调控参数,进行仿真模拟.结果表明,当水技术进步因子由1提高到1.6,水资源循环利用率由0.45提高到0.85,污水处理投资率由0.18提高到0.25,万元产值年耗水量由236.8 t·a-1降为175.4 t·a-1,日人均用水量由0.18 t·d-1降为0.12 t·d-1时,园区工业总产值增长率5年可达到44.4%,水资源存量年均增幅为0.03%,水资源供需比为2.25,系统达到相对最优状态.     

Accuracy analysis of multiple structure alignments

Protein structure alignment methods are essential for many different challenges in protein science, such as the determination of relations between proteins in the fold space or the analysis and prediction of their biological function. A number of different pairwise and multiple structure alignment (MStA) programs have been developed and provided to the community. Prior knowledge of the expected alignment accuracy is desirable for the user of such tools. To retrieve an estimate of the performance of current structure alignment methods, we compiled a test suite taken from literature and the SISYPHUS database consisting of proteins that are difficult to align. Subsequently, different MStA programs were evaluated regarding alignment correctness and general limitations. The analysis shows that there are large differences in the success between the methods in terms of applicability and correctness. The latter ranges from 44 to 75% correct core positions. Taking only the best method result per test case this number increases to 84%. We conclude that the methods available are applicable to difficult cases, but also that there is still room for improvements in both, practicability and alignment correctness. An approach that combines the currently available methods supported by a proper score would be useful. Until then, a user should not rely on just a single program.     

Crystal structure of yeast YER010Cp, a knotable member of the RraA protein family

We present here the structure of Yer010c protein of unknown function, solved by Multiple Anomalous Diffraction and revealing a common fold and oligomerization state with proteins of the regulator of ribonuclease activity A (RraA) family. In Escherichia coli, RraA has been shown to regulate the activity of ribonuclease E by direct interaction. The absence of ribonuclease E in yeast suggests a different function for this family member in this organism. Yer010cp has a few supplementary secondary structure elements and a deep pseudo-knot at the heart of the protein core. A tunnel at the interface between two monomers, lined with conserved charged residues, has unassigned residual electron density and may constitute an active site for a yet unknown activity.     

Database searching by flexible protein structure alignment

We have recently developed a flexible protein structure alignment program (FATCAT) that identifies structural similarity, at the same time accounting for flexibility of protein structures. One of the most important applications of a structure alignment method is to aid in functional annotations by identifying similar structures in large structural databases. However, none of the flexible structure alignment methods were applied in this task because of a lack of significance estimation of flexible alignments. In this paper, we developed an estimate of the statistical significance of FATCAT alignment score, allowing us to use it as a database-searching tool. The results reported here show that (1) the distribution of the similarity score of FATCAT alignment between two unrelated protein structures follows the extreme value distribution (EVD), adding one more example to the current collection of EVDs of sequence and structure similarities; (2) introducing flexibility into structure comparison only slightly influences the sensitivity and specificity of identifying similar structures; and (3) the overall performance of FATCAT as a database searching tool is comparable to that of the widely used rigid-body structure comparison programs DALI and CE. Two examples illustrating the advantages of using flexible structure alignments in database searching are also presented. The conformational flexibilities that were detected in the first example may be involved with substrate specificity, and the conformational flexibilities detected in the second example may reflect the evolution of structures by block building.     

Sequence determinants of quaternary structure in lumazine synthase

Riboflavin, an essential cofactor for all organisms, is biosynthesized in plants, fungi and microorganisms. The penultimate step in the pathway is catalyzed by the enzyme lumazine synthase. One of the most distinctive characteristics of this enzyme is that it is found in different species in two different quaternary structures, pentameric and icosahedral, built from practically the same structural monomeric unit. In fact, the icosahedral structure is best described as a capsid of twelve pentamers. Despite this noticeable difference, the active sites are virtually identical in all structurally studied members. Furthermore, the main regions involved in the catalysis are located at the interface between adjacent subunits in the pentamer. Thus, the two quaternary forms of the enzyme must meet similar structural requirements to achieve their function, but, at the same time, they should differ in the sequence traits responsible for the different quaternary structures observed. Here, we present a combined analysis that includes sequence-structure and evolutionary studies to find the sequence determinants of the different quaternary assemblies of this enzyme. A data set containing 86 sequences of the lumazine synthase family was recovered by sequence similarity searches. Seven of them had resolved three-dimensional structures. A subsequent phylogenetic reconstruction by maximum parsimony (MP) allowed division of the total set into two clusters in accord with their quaternary structure. The comparison between the patterns of three-dimensional contacts derived from the known three-dimensional structures and variation in sequence conservation revealed a significant shift in structural constraints of certain positions. Also, to explore the changes in functional constraints between the two groups, site-specific evolutionary rate shifts were analyzed. We found that the positions involved in icosahedral contacts suffer a larger increase in constraints than the rest. We found eight sequence sites that would be the most important icosahedral sequence determinants. We discuss our results and compare them with previous work. These findings should contribute to refinement of the current structural data, to the design of assays that explore the role of these positions, to the structural characterization of new sequences, and to initiation of a study of the underlying evolutionary mechanisms.     

In silico local structure approach: a case study on outer membrane proteins

The detection of Outer Membrane Proteins (OMP) in whole genomes is an actual question, their sequence characteristics have thus been intensively studied. This class of protein displays a common beta-barrel architecture, formed by adjacent antiparallel strands. However, due to the lack of available structures, few structural studies have been made on this class of proteins. Here we propose a novel OMP local structure investigation, based on a structural alphabet approach, i.e., the decomposition of 3D structures using a library of four-residue protein fragments. The optimal decomposition of structures using hidden Markov model results in a specific structural alphabet of 20 fragments, six of them dedicated to the decomposition of beta-strands. This optimal alphabet, called SA20-OMP, is analyzed in details, in terms of local structures and transitions between fragments. It highlights a particular and strong organization of beta-strands as series of regular canonical structural fragments. The comparison with alphabets learned on globular structures indicates that the internal organization of OMP structures is more constrained than in globular structures. The analysis of OMP structures using SA20-OMP reveals some recurrent structural patterns. The preferred location of fragments in the distinct regions of the membrane is investigated. The study of pairwise specificity of fragments reveals that some contacts between structural fragments in beta-sheets are clearly favored whereas others are avoided. This contact specificity is stronger in OMP than in globular structures. Moreover, SA20-OMP also captured sequential information. This can be integrated in a scoring function for structural model ranking with very promising results.     

寨卡病毒蛋白结构与功能研究进展

2015年以来,南美暴发大规模寨卡疫情,因其与新生儿小头症等严重神经发育疾病密切相关,被世界卫生组织列为国际关注的突发公共卫生事件。与其他虫媒黄病毒类似,寨卡病毒为单股正链RNA病毒,其基因组编码的3种结构蛋白构成病毒颗粒,7种非结构蛋白参与病毒复制生活周期的调控。在全球科学家的共同努力下,寨卡病毒蛋白结构与功能的研究取得了突破性进展,极大地促进研究者对病毒复制与致病机制的认识,也为疫苗和药物研发提供了重要科学依据和潜在靶标。本文将对寨卡病毒蛋白的结构与功能的最新研究进展作一综述,并讨论当前面临的挑战和机遇。     

Neural networks for secondary structure and structural class predictions

A pair of neural network-based algorithms is presented for predicting the tertiary structural class and the secondary structure of proteins. Each algorithm realizes improvements in accuracy based on information provided by the other. Structural class prediction of proteins nonhomologous to any in the training set is improved significantly, from 62.3% to 73.9%, and secondary structure prediction accuracy improves slightly, from 62.26% to 62.64%. A number of aspects of neural network optimization and testing are examined. They include network overtraining and an output filter based on a rolling average. Secondary structure prediction results vary greatly depending on the particular proteins chosen for the training and test sets; consequently, an appropriate measure of accuracy reflects the more unbiased approach of “jackknife” cross-validation (testing each protein in the database individually).     

Describing RNA structure by libraries of clustered nucleotide doublets

The rapidly increasing wealth of structural information on RNA and knowledge of its varying roles in biology have facilitated the study of RNA structure using computational methods. Here, we present a new method to describe RNA structure based on nucleotide doublets, where a doublet is any two nucleotides in a structure. We restrict our search to doublets that are close together in space, but not necessarily in sequence, and obtain doublet libraries of various sizes by clustering a large set of doublets taken from a data set of high-resolution RNA structures. We demonstrate that these libraries are able to both capture structural features present in RNA and fit local RNA structure with a high level of accuracy. Libraries ranging in size from ten to 100 doublets are examined, and a detailed analysis shows that a library with as few as 30 doublets is sufficient to capture the most common structural features, while larger libraries would be more appropriate for accurate modeling. We anticipate many uses for these libraries, from annotation to structure refinement and prediction.     

Searching protein structure databases has come of age

The number of protein structures known in atomic detail has increased from one in 1960 (Kendrew, J. C., Strandberg, B. E., Hart, R. G., Davies, D. R., Phillips, D. C., Shore, V. C. Nature (London) 185:422–427, 1960) to more than 1000 in 1994. The rate at which new structures are being published exceeds one a day as a result of recent advances in protein engineering, crystallography, and spectroscopy. More and more frequently, a newly determined structure is similar in fold to a known one, even when no sequence similarity is detectable. A new generation of computer algorithms has now been developed that allows routine comparison of a protein structure with the database of all known structures. Such structure database searches are already used daily and they are beginning to rival sequence database searches as a tool for discovering biologically interesting relationships. © 1994 Wiley-Liss, Inc.