居民活动空间与生态约束协调的城市开发边界划定方法——以长沙市为例

为了遏制长沙市城市的无序扩张,促进土地节约集约、高效利用,保障生态空间质量,划定长沙市城市开发边界成为重要举措。基于居民活动空间扩展,选取人口密度、居民活动分布、基础设施布局等多源时空数据,通过量化居民活动空间扩展概率,并利用植被覆盖度构建生态约束强度,确定二者协调规则,作为CA模型的约束条件,进行城市建设用地模拟,划定城市开发边界。结果表明：划定的长沙市城市开发边界,结果与长沙市“十三五”规划的城市空间发展框架基本一致,对未来建设用地扩展方向预测合理,而且避免了侵占重要生态资源,达到了兼顾城市空间发展和生态资源保护的多重目的。     

Entrepreneurial motivation: A review of the literature and an agenda for future research

Given the substantial impact that new ventures have on the global economy, understanding what motivates entrepreneurs is of both practical and theoretical importance. Although research on the nature, causes, and consequences of entrepreneurial motivation has grown rapidly, it has evolved in distinct theoretical silos that tend to isolate motives based on the phase of business development (e.g., initiation, growth, and exit) rather than acknowledge that individuals often traverse all these phases and experience multiple types of motivation throughout their entrepreneurial journey. To advance the study of motivation in the fields of entrepreneurship and organizational behavior and provide a means through which these advancements can contribute to our understanding of how motivation drives the start-up, growth, and exiting of businesses, we organize and review the extant literature on entrepreneurial motives based on the phases of the new venture process. In doing so, this article develops a roadmap of the current state of entrepreneurial motivation research and its nomological network and provides suggestions to guide future research in extending our understanding of motivation in the entrepreneurship domain as well as in traditional organizational settings.     

1980--2009年中国经济增长对化石能源消耗的依赖关系

随着中国经济的发展,我国高化石能源消耗问题也越来越突出。计算了1980--2009年中国人均化石能源足迹,并将其与人均GDP联系起来进行研究,发现在这30年中我国人均化石能源消耗和人均GDP都呈现逐步增长趋势,在用E—G两步法进行协整检验的过程中发现两者存在长期稳定的均衡关系;采用格兰杰因果检验进行进一步的验证分析发现,我国人均化石能源足迹和人均GDP之间互为因果关系,进一步说明我国经济发展对能源消耗尤其是化石能源消耗具有依赖性,且经济发展会进一步刺激化石能源使用的增加。因此,采取节能降耗措施应从调整产业结构和能源消费结构入手,在降低能耗期间我国会出现经济增长放缓的现象。     

社会资本与经济增长及环境影响的关系研究

"社会资本"作为一个多维度的概念,近年来引起了全世界的广泛关注。大量证据已证明,高水平的社会资本是生态、社会和经济职责和谐过程的先决条件,社会资本对于促进经济增长、缓解贫困、提高工程绩效、管理自然资源与保护环境非常关键。本文阐释了社会资本概念,分析了社会资本的主要成分、分析层次及主要类型等维度,指出社会资本的主要成分包括网络、规范、制裁,分析层次包括个体、中观、宏观,主要类型包括结合型、沟通型、联系型;在此基础上,梳理总结了社会资本与经济增长及环境影响关系的国际研究进展,阐释了社会资本促进经济增长、影响生态环境的作用机理,分析了社会资本与适应能力的关系,简要介绍了国际上理解和研究社会系统与关键资源之间的相互作用和影响的思想框架。最后,讨论分析了社会资本与经济增长、环境影响的关系研究中需要进一步完善的问题。     

Decoupling Relationship Between Cultivated Land Occupation by Construction and Economic Growth in China During 1998-2007

With the rapid development of economy, the conversion of cultivated land into nonagricultural land occurs more frequently and makes cultivated land sparser. This article based on the decoupling theory takes the situations of cultivated land occupation by construction and economic growth in China from 1998 to 2007 as an example to evaluate and analyze the decoupling. The conclusions are drawn as follows. First, the article applies IU curve and gross method. The decoupling status by gross method, in contrast to that by IU curve, can express the pressure from cultivated land occupation better and is similar to the decoupling status based on the model of decoupling in this article. Second, in most provinces of China, the relationship between the cultivated land occupation by construction and economic growth has transformed from expansive negative decoupling to strong decoupling. In general, the transformation was firstly from economically advanced eastern municipalities under the central government directly, then to economically advanced eastern coastal provinces, and lastly to central, western and northeastern regions. Third, the decoupling status was relative to contemporaneous policies and laws on cultivated land protection and regional development planning. Their effect is obvious and positive.     

一株氧化亚铁硫杆菌的筛选及生长条件研究

从广东省大宝山矿区尾矿中分离纯化得到一株嗜酸细菌,对其进行DNA提取和16S rRNA扩增后测序,将测序结果与国际基因数据库Genbank中已有相关菌株序列进行相似性比对后,发现该菌株与氧化亚铁硫杆菌(Acidithiobacil-lus ferrooxidans)Tf-49菌位于系统发育树的同一分支中,二者相似度高达99%以上,确定其为氧化亚铁硫杆菌并命名为DBS-8菌。另外,通过设计5因素4水平的正交实验,研究了接种量、培养温度、硫酸铵浓度、初始pH和初始亚铁浓度对该菌株生长状况的影响。结果表明适宜该菌株生长的最佳初始条件为:20%的接种量、3.0 g/L硫酸铵、9.0 g/L初始亚铁、pH=2.0和28℃培养,各初始条件对细菌生长影响的顺序为:pH初始亚铁浓度接种量温度硫酸铵浓度。     

煤基腐殖酸对外源砷胁迫下玉米生长及生理性状的影响

为了筛选用于砷污染土壤治理的煤基腐殖酸,采用盆栽实验研究了施用不同种类和浓度的煤基腐殖酸及EDTA对外源砷胁迫下玉米株高、株鲜重、株干重、根干重、砷积累量、叶片抗氧化酶（POD,SOD和CAT）活性和脯氨酸含量的影响。结果表明,11种供试煤基腐殖酸均促进了玉米生长,提高了叶片POD、SOD和CAT活性。其中6和10号腐殖酸可降低土壤砷活性和显著抑制玉米吸收和积累砷,而8和9号腐殖酸增加了土壤活性砷和显著促进了玉米对砷的吸收和累积,且不同程度地强于EDTA。除8和9号外,其余腐殖酸均可明显降低玉米叶片脯氨酸的含量。EDTA可显著促进玉米吸收和积累砷,且加剧了砷对玉米的危害。因此,8和9号供试煤基腐殖酸可以替代EDTA活化土壤砷,与植物配合以提高砷污染土壤的植物修复速度和效果,而6和10号供试煤基腐殖酸则可用于土壤砷钝化剂,以保证作物产品的安全。     

Growth and photosynthetic responses to copper in wild grapevine

The present study evaluates the tolerance and accumulation potential of Vitis vinifera ssp. sylvestris under moderate and high external Cu levels. A greenhouse experiment was conducted in order to investigate the effects of a range of external Cu concentrations (0–23 mmol L⁻¹) on growth and photosynthetic performance by measuring gas exchange, chlorophyll fluorescence parameters and photosynthetic pigments. We also measured the total copper, nitrogen, phosphorus, sulphur, calcium, magnesium, iron, potassium and sodium concentrations in the plant tissues. All the experimental plants survived even with external Cu concentrations as high as 23 mmol L⁻¹ (1500 mg Cu L⁻¹), although the excess of metal resulted in a biomass reduction of 35%. The effects of Cu on growth were linked to a reduction in net photosynthesis, which may be related to the effect of the high concentration of the metal on photosynthetic electron transport. V. vinifera ssp. sylvestris survived with leaf Cu concentrations as high as 80 mg kg⁻¹ DW and growth parameters were unaffected by leaf tissue concentrations of 35 mg Cu kg⁻¹ DW. The results of our study indicate that plants of V. vinifera ssp. sylvestris from the studied population are more tolerant to Cu than the commercial varieties of grapevine that have been studied in the literature, and could constitute a basis for the genetic improvement of Cu tolerance in grapevine.     

Food utilization and growth of cutworm Spodoptera litura Fabricius larvae exposed to nickel,and its effect on reproductive potential

Food utilization and growth of the 5th and 6th instar Spodoptera litura Fabricius larvae, and its effect on reproduction potential was evaluated by feeding larvae diets with different doses of Ni for 3 generations. Dose-dependent relationships between Ni levels and food consumption and growth were variable with different larval developmental period and Ni exposure duration. RCR, AD and RGR of the 6th instar larvae were much more affected by Ni exposure than those of 5th instar larvae, and the effects were strongest in the 3rd generation. It was found that RCR was significantly stimulated after 1 and 20 mg kg⁻¹ Ni exposure, while AD was significantly inhibited after 1, 5, 10 and 40 mg kg⁻¹ Ni exposure. However, lower levels of Ni (?5 mg kg⁻¹) significantly increased and higher levels of Ni (?10 mg kg⁻¹) significantly decreased RGR. In 3 successive generations, 10 mg kg⁻¹ Ni significantly increased the ECI and ECD of the 5th instar larvae, and 5 mg kg⁻¹ Ni significantly increased the ECD of the 6th instar larvae. However, ECD were all significantly inhibited with 20 mg kg⁻¹ Ni exposure. Results also revealed that durations of larvae were shortened at low levels of Ni, but extended at high levels of Ni. Fecundity was inhibited by the highest Ni doses in each generation, while improved by low Ni doses in the 3rd generation. Hatching rates in all treatments were significantly decreased in a Ni dose-dependent manner. Study indicated that effects of Ni on these parameters were predominant with the increasing Ni exposure period.     

应用细胞合成计量关系模型分析鱼腥藻7120的混合营养生长

根据文献中鱼腥藻细胞大分子的含量和组成情况,计算了细胞合成所需要的小分子单体和前体代谢物的量,得到代谢意义上的细胞生物合成计量关系,此计量关系模型,对鱼腥藻7120细胞在气升式光生物反应器中光自养和混合营养生长的对数生长阶段进行了代谢通量分析。结果表明,葡萄糖的利用影响细胞初级碳代谢的流动状况,混合营养生长过程比光自养生长过程磷酸戊糖途径氧化性分支的反应程度明显加强,随着培养的进行,葡萄糖被细胞用作碳源的比例可能减小,而用作能源的比例可能增大。