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81.
青藏高原山水林田湖草生态保护修复模式——以拉萨河流域为例 总被引:2,自引:0,他引:2
山水林田湖草生态保护与修复是推进生态文明建设的必然要求。青藏高原是我国生态屏障区、水源涵养区和生态脆弱区,生态地位独特、生态保护责任重大。为此,中央及地方政府高度重视青藏高原生态文明建设,积极开展山水林田湖草生态保护修复试点工程。从青藏高原山水林田湖草生态保护与修复试点的特殊性出发,以拉萨河流域为例梳理了其主要的生态保护修复工程项目,提炼了青藏高原山水林田湖草生态保护与修复的技术路线,从参与主体、整合要素、运行保障、实施目标等方面总结了青藏高原多部门跨区、多要素综合、多渠道协作、多目标耦合的山水林田湖草联动治理模式,从山、水、林、田、湖、草六大生态要素出发归纳了青藏高原生态保护修复的分类指导-精准施策的实践框架,以期对青藏高原山水林田湖草生态建设情况有一个清晰的认识,并为全国其他地区系统开展山水林田湖草生态保护修复工作提供借鉴。 相似文献
82.
水生态一、二级分区技术框架 总被引:8,自引:1,他引:7
水生态功能分区是流域水环境分类、分级、分区、分期管理的基础。回顾总结国内外水生态功能分区工作的基础上,针对我国流域水生态功能一、二级分区工作,提出了一个可供参考的分区指标体系,探讨了流域尺度水生态分区技术框架的构建以及可能存在的问题。该技术框架主要由3部分内容组成:环境要素对水生态因子的驱动机制、分区指标体系和分区技术。作为技术框架的理论依据,驱动机制分析首先以水-陆生态水文耦合模型为框架对环境要素如何影响水生态系统功能进行阐述。指标体系是技术框架的基础部分,主要包括水生态因子和环境要素两大类,其中一级分区指标包括气候、水文和地貌等要素,二级分区指标包括水质、水生动植物、藻类、土壤、植被、土地利用和社会经济要素。针对一、二级水生态功能区采用"自上而下"和"自下而上"的分区方法,为技术框架付诸现实提供了保障。为正在进行的各大流域水生态功能分区工作提供一定的参考依据,同时也希望在这些具体分区工作的基础上能进一步完善本分区技术框架。 相似文献
83.
Ahsan Mushir Shemsi Firdous Ahmad Khanday Ahsanulhaq Qurashi Amjad Khalil Gea Guerriero Khawar Sohail Siddiqui 《Biotechnology advances》2019,37(3):357-381
Numerous enzymes of biotechnological importance have been immobilized on magnetic nanoparticles (MNP) via random multipoint attachment, resulting in a heterogeneous protein population with potential reduction in activity due to restriction of substrate access to the active site. Several chemistries are now available, where the modifier can be linked to a single specific amino acid in a protein molecule away from the active-site, thus enabling free access of the substrate. However, rarely these site-selective approaches have been applied to immobilize enzymes on nanoparticles. In this review, for the first time, we illustrate how to adapt site-directed chemical modification (SDCM) methods for immobilizing enzymes on iron-based MNP. These strategies are mainly chemical but may additionally require genetic and enzymatic methods. We critically examine each method and evaluate their scope for simple, quick, efficient, mild and economical immobilization of enzymes on MNP. The improvements in the catalytic properties of few available examples of immobilized enzymes are also discussed. We conclude the review with the applications and future prospects of site-selectively modified magnetic enzymes and potential benefits of this technology in improving enzymes, including cold-adapted homologues, modular enzymes, and CO2-sequestering, as well as non-iron based nanomaterials. 相似文献
84.
Christa Renetzeder Stefan Schindler Johannes Peterseil Martin A. Prinz Sander Mücher Thomas Wrbka 《Ecological Indicators》2010,10(1):39-48
European landscapes have been shaped over the centuries by processes related to human land use, which are reflected in regionally distinct landscape patterns. Since landscape pattern has been linked to biodiversity and other ecological values of the landscapes, this paper explores landscape pattern as a tool for ecological sustainability assessments at the regional (Austrian Cultural Landscapes), national (Austria) and European (European Union + Norway, Switzerland) level with focus on agricultural landscapes. A set of landscape metrics served as a basis to assess naturalness and geometrisation of Austrian and European landscapes as a proxy for their sustainability. To achieve an accurate spatially explicit assessment, we applied a spatial reference framework consisting in units that are homogeneous in biophysical and socio-economic contexts, adapted the regional approach for its application at European level, and developed relative sustainability thresholds for the landscape metrics. The analyses revealed that several landscape metrics, particularly the “Number of Shape Characterising Points” showed a high correlation with the degree of naturalness. The sustainability map of Austria based on an ordinal regression model revealed well-known problem regions of ecological sustainability. At the European level, the relative deviation from the average pattern showed clearly the simplification processes in the landscapes. However, a better spatial resolution of land cover data would add to the refinement of pattern analysis in regions and therefore the assessment of sustainability. We recommend the combination of information of different scales for the formulation and implementation of sustainability policies. 相似文献
85.
Self-assembly reaction of Cd(ClO4)2 · 6H2O with Norfloxacin (H-Norf) affords a novel 2D rectangular grid framework [Cd(Norf)(ClO4)(H2O)] (1) with strong blue luminescent emission (λem=425 nm), while Norf− acts as a tetradentate bridging linker to connect three Cd centers and ClO4 − completes Cd center octahedron coordination geometry. The compound 1 has crystallographic data of triclinic, space group , a=9.4577(1) Å, b=9.5012(2) Å, c=12.2805(1) Å, V=3624.4(3) Å3, Z=2. 相似文献
86.
87.
21世纪以来都市圈快速扩张对区域社会-生态系统的可持续发展构成威胁,基于动态演进视角的区域社会-生态系统运行机制解析备受关注。以南京都市圈为例,从区域和城市两个尺度,基于适应性循环理论与压力-状态-响应框架解析2000—2019年近20年来都市圈社会-生态系统的交互适应循环阶段,以及每个阶段系统的差异化应激响应机制。研究表明南京都市圈社会-生态系统整体经历了3个适应循环周期,现处于新一轮的适应性循环阶段,系统适应性呈上升趋势,但社会子系统和生态子系统尚未取得协调。都市圈内各城市的社会-生态系统演进类型有所不同,可分为稳定增长型、波动增长型、不均衡发展型和生态危机型四类。未来需要采取差异化的社会-生态系统治理策略,确保都市圈整体优化发展。 相似文献
88.
Liangming Hu 《Inorganica chimica acta》2008,361(8):2439-2446
A series of zinc phosphite hybrid structures with trimethylene dipyridine as the linking ligand and templated on the aromatic alcohols, hydroquinone, 1,2,3-trihydroxybenzene, nitrophenol, and bromophenol are reported. The aromatic alcohols interact with the framework by hydrogen bonding to oxygen atoms that bridge zinc and phosphorus atoms in the inorganic portion of the network. In addition, three hydrogen-bonded networks that contain trimethylene-dipyridine and either hydroquinone or 1,2,3-trihydroxybenzene are reported. In these structures, the aromatic alcohol acts as a hydrogen bond donor to trimethylene-dipyridine. The flexibility of trimethylene-dipyridine is important to the construction of the new frameworks. Calculations using PM5 parameters demonstrate that trimethylene-dipyridine can adopt a wide variety of conformations with a minimal energy expense. 相似文献
89.
《Animal : an international journal of animal bioscience》2014,8(7):1080-1088
A total of 600 Ross 308-day-old male broiler chicks were used in a 28 day digestibility study to investigate the interaction between dietary calcium (Ca) and non-phytate phosphorus (nPP) on the digestibility of minerals and amino acids. Diets were formulated to be nutritionally adequate except for Ca and nPP. Fifteen mash diets based on corn and soya bean meal with varying concentrations of Ca (6.4 to 12.0 g/kg) and nPP (2.4 to 7.0 g/kg) were used. Diets were clustered around total densities of Ca and nPP of 12, 13.5 or 15.0 (g/kg) and within each density, a range of five Ca : nPP ratios (1.14 : 1, 1.5 : 1, 2.0 : 1, 2.75 : 1 and 4.0 : 1) were fed. Birds had free access to feed and water throughout the study. At day 28, birds were euthanised for the determination of apparent ileal mineral and amino acid digestibility. Data were modelled in R version 2.15 using a linear mixed-effects model and interrogation of the data was performed by fitting a low order polynomial function. At high Ca concentrations, increasing nPP led to an increase in the apparent digestibility of minerals. Apparent ileal digestibility of phosphorus (P) was enhanced with increasing dietary nPP up to 5.5 g/kg beyond which no improvements were found. Maximal Ca digestibility was found in diets with >8.0 g/kg Ca with concomitant low concentrations of nPP. Diets with a broader Ca : nPP ratio improved the digestibility of Ca but were deleterious to the digestibility of P. In this study, apparent digestibility of amino acids was broadly unaffected by dietary Ca and nPP concentrations. However, interactions between Ca and nPP were observed for the digestibility of glutamine, tyrosine and methionine (all P<0.001). Nitrogen digestibility showed discrete optima around 10.0 and 5.0 g/kg nPP and Na digestibility was maximised around 8 to 9.0 g/kg Ca and 4.5 to 5.4 g/kg nPP. These data show that the ratio of Ca : nPP is more influential to mineral digestibility than the absolute dietary concentration of each macro mineral. 相似文献
90.
This article demonstrates that elicited dream narratives use a differing narrative structural and functional framework, as proposed by Labov and Waletzky's (1967) narrative framework on elicited personal narratives. A quantitative structural and functional analysis of five male and female collected samples showed that dream narratives follow a homogenous structure of (1) Topic introduction, (2) Orientation, (3) Complication, (4) Evaluation, and (5) Coda, consequently reflecting the omission of Labov and Waletzky's (1967) proposed resolution unit, which confirms Labov's (1997) suggestion of the difficulty to distinguish between resolution and coda. Moreover, this article devotes attention to specific structural particularities, proposing that analepses and prolepses might indicate, firstly, the simultaneous processing of new spatial information and new protagonists, and secondly, reflecting indirectly the experience of dream bizarreness. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献