新疆农牧区贫困户参与旅游精准扶贫行为

以新疆农牧区贫困户为研究对象,采用计划行为理论模型以及双槛模型的方法,研究了影响贫困户的参与行为,以期提出减贫路径。结果表明:农牧民是否参与旅游精准扶贫的行为前提为是否有一定的参与意愿。贫困户的个人特征中,家庭创业、人均纯收入、通用电对参与旅游精准扶贫产生了正向的促进作用,与村主干路距离、外出务工人员、思想动力不足导致的贫困对参与旅游精准扶贫产生了负面影响;在行为规范中,指令性规范、示范性规范、合作态度对旅游精准扶贫中的前景看好、知觉行为控制力对农牧民参与旅游精准扶贫产生了正面影响。     

阿克苏地区红枣产业比较优势分析

以阿克苏地区红枣产业发展为依托,结合比较优势理论的原理、方法,分析论证了阿克苏地区红枣产业发展的状况,根据比较优势的结果得出阿克苏地区红枣效率优势相对较弱、规模优势明显、综合比较优势呈逐年递增态势等结果,并就优化、推进阿克苏地区红枣产业发展提出了改善品种结构,提升科技含量、加强产业组织经营、实施品牌发展战略等对策和建议。     

Stewardship as a Path to Cooperation? Exploring the Role of Identity in Intergroup Conflict Among Michigan Wolf Stakeholders

Post-recovery wolf management remains controversial. In Michigan, dialogue centers on hunting wolves but controversy may be more nuanced than simple pro- or anti-hunting positions. Social identity may cause stakeholders to organize in groups and identity differences may be driving controversy. To explore stakeholder disagreement over wolf management, we conducted semi-structured key informant interviews (n = 21) about identity and stewardship in August–September 2012. Four overarching identity themes emerged regarding: (a) management objectives, (b) focal levels, (c) control methods, and (d) justifications for methods. Themes indicated two main researcher-defined identity groups. Interviewees from both groups identified six common stewardship themes: (a) bequest values, (b) ecosystem health, (c) education, (d) existence values, (e) pride in natural resources, and (f) sustainability. Findings suggest stakeholders may be conflicting over opposing identities vis-à-vis organization affiliation, which may be related to what management strategies individuals oppose. Establishing common stewardship objectives through established participation methods may help alleviate controversy.     

岩土计算中的弾塑性理论

岩土工程计算是一个复杂的系统工程,它涉及面广,包括高等数学、数值分析、计算机程序、弾塑性力学和岩土力学与工程等等学科知识.本文着重对该计算中所涉及到的主要弾塑性理论加以阐述,并讨论岩土计算中还有待于深入研究的部分课题.     

民勤绿洲生态环境脆弱性模糊物元分析评价

针对民勤绿洲水资源、环境和土地利用现状,利用定量分析方法对民勤绿洲生态环境脆弱性进行总体评价.在分析影响民勤绿洲生态环境因素的基础上,将模糊理论、层次分析法和物元可拓集合有机结合起来,建立了民勤绿洲生态环境脆弱性评价的模糊物元模型.该模型充分考虑水资源、环境、土地资源和人工干预等指标.计算结果表明:民勤绿洲生态环境脆弱性状况总体评价为Ⅲ级,即非常脆弱.该方法简捷、易于计算编程,为西北旱区生态环境脆弱性评价提供了一种新的思路.     

An Approach for Estimating the Final Ultimate-bearing Capacity of Driven Pile In Soft Clay

The prefabricated pile,driven in soft clay,can squeeze the soil laterally in a certain scope around the pile,and the void ratio is reduced significantly;consequently,the shear bearing capacity is raised.But the soil parameter,which is used to estimate the capacity of pile,is reduced according to the soil state before the pile was driven.Then,a certain difference appears when the pile is working.The calculation result usually is partial to conservative.This paper analyzes the squeezing mechanism of the pile using the theory of cylindrical cavities expansion.And a formula,which is used to estimate the increment of shear bearing capacity of soil around the pile when excess pore water pressure from pile driving distributes completely,is presented based on the unique relation between the shear bearing capacity and the density of the soil.This formula can be used to estimate the final ultimate-bearing capacity of the pile.The calculated results by the proposed formula are in good agreement with those of the site measurement.     

Can trail spatial attributes predict trail use level in urban forest park? An examination integrating GPS data and space syntax theory

Understanding users’ spatial distribution in forest park is crucial for providing visitors with quality recreation experiences and for park planning and management. Utilizing users’ spatial distribution data, this study aims at investigating associations between trail use level and trail spatial attributes, through examining two large urban forest parks (Gongqing forest park and Paotaiwan forest park) in Shanghai, China. Users’ spatial distribution was measured utilizing GPS trackers with the interval of 10 seconds. This study conceptualizes trail spatial attributes as trail metric attributes and trail configurational attributes. Trail metric attributes include trail mean distance to gates, length, width and level of enclosure, which are calculated based on park map and on-site observation. We computed trail configurational attributes utilizing space syntax theory, which comprise measures of global integration, control, and connectivity. Trail connection with features/facilities, visual connection with water and shading are included as covariate variables. In total, we obtained 134 valid samples in Gongqing forest park and 210 valid samples in Paotaiwan forest park for analysis. Multivariate regression analyses indicate that when involving covariate variables, consistently in both parks, a greater trail usage is significantly related to trail shorter mean distance to park gate, trail width wider than 3 meters, higher global integration and higher control values. Collectively, these four trail spatial attributes explained 31.7 % (p < 0.001) and 27.3 % (p < 0.001) of the variances in trail use level in Gongqing forest park and Paotaiwan forest park. These findings provide direct implications to park designers and managers for providing visitors with different desirable social conditions, and ultimately improve users’ experiences and satisfactions.     

Computational chemistry study of the environmentally important acid-catalyzed hydrolysis of atrazine and related 2-chloro-s-triazines

Many chlorine-containing pesticides, for example 2-chloro-s-triazines, are of great concern both environmentally and toxicologically. As a result, ascertaining or predicting the fate and transport of these compounds in soils and water is of current interest. Transformation pathways for 2-chloro-s-triazines in the environment include dealkylation, dechlorination (hydrolysis), and ring cleavage. This study explored the feasibility of using computational chemistry, specifically the hybrid density functional theory method, B3LYP, to predict hydrolysis trends of atrazine (2-chloro-N4-ethyl-N6-isopropyl-1,3,5-triazine-2,4-diamine) and related 2-chloro-s-triazines to the corresponding 2-hydroxy-s-triazines. Gas-phase energetics are described on the basis of calculations performed at the B3LYP/6-311++G(d,p)//B3LYP/6-31G* level of theory. Calculated free energies of hydrolysis (delta h G298) are nearly the same for simazine (2-chloro-N4,N6-diethyl-1,3,5-triazine-2,4-diamine), atrazine, and propazine (2-chloro-N4,N6-di-isopropyl-1,3,5-triazine-2,4-diamine), suggesting that hydrolysis is not significantly affected by the side-chain amine-nitrogen alkyl substituents. High-energy barriers also suggest that the reactions are not likely to be observed in the gas phase. Aqueous solvation effects were examined by means of self-consistent reaction field methods (SCRF). Molecular structures were optimized at the B3LYP/6-31G* level using the Onsager model, and solvation energies were calculated at the B3LYP/6-311++G(d,p) level using the isodensity surface polarizable continuum model (IPCM). Although the extent of solvent stabilization was greater for cationic species than neutral ones, the full extent of solvation is underestimated, especially for the transition state structures. As a consequence, the calculated hydrolysis barrier for protonated atrazine is exaggerated compared with the experimentally determined one. Overall, the hydrolysis reactions follow a concerted nucleophilic aromatic substitution (SNAr) pathway.     

Relationships between landcover proportion and indices of landscape spatial pattern

Recent studies have related percolation theory and critical phenomena to the spatial pattern of landscapes. We generated simulated landscapes of forest and non-forest landcover to investigate the relationship between the proportion of forest (P_i) and indices of patch spatial pattern. One set of landscapes was generated by randomly assigning each pixel independently of other pixels, and a second set was generated by randomly assigning rectilinear clumps of pixels. Indices of spatial pattern were calculated and plotted against P_i. The random-clump landscapes were also compared with real agricultural landscapes. The results support the use of percolation models as neutral models in landscape ecology, and the performance of the indices studied with these neutral models can be used to help interpret those indices calculated for real landscapes.     

披碱草属野生种质材料在干旱与半干旱区适应性评价

应用灰色理论系统,以搜集自我国8省区的38份披碱草属植物野生种质材料为研究对象,对其株高、叶面积生长动态、草产量、茎叶比、鲜干比及种子产量进行灰色关联度分析.结果表明,株高从拔节期到抽穗期增幅较大,而叶面积从分蘖期到拔节期增幅较大;38份材料鲜草及干草产量差异较大,变异系数分别为39.275％和43.087％;大部分种质材料茎叶比在1.0～2.0之间;不同材料种子产量的变异系数较大;产量与各主要农艺性状的关联度大小顺序为:鲜干比＞种子产量＞茎叶比＞叶面积＞株高.综合分析发现,适应性较好的种质材料有NMC32、BJT37、QHD19、SXD36、XJD11、XJD15、XJS8、XJT2、XJE13和XJD5.