农户有限理性土地利用行为决策影响因素——以陕西省米脂县高西沟村为例

利用有限理性理论与方法进行行为决策研究已成为多样化决策研究中的热点。研究微观尺度土地利用变化中农户有限理性行为决策的影响因素,对于揭示农户土地利用驱动因子、调整农户决策行为与优化农业景观格局具有重要的理论与现实意义。论文以陕西省米脂县高西沟村为例,通过构建农户效应收益模型,利用2009—2011年农户调查数据揭示理性最优决策与农户实际决策之间的差异性;利用体现农户行为满意度的Probit模型分析有限理性决策的影响因素。结论为:①高西沟村农户理性最优决策与实际决策差异性较大,说明农户在实践中采用有限理性进行土地利用生产;②构建Probit模型模拟农户满意度决策行为态度,选取的4类变量较好地解释了农户决策的影响因子。其中,农业收入回归系数为0.78、反映相对经济地位下降变量0.41、退耕面积-0.42、耕地面积-0.62、打工收入-0.34、性别0.48、劳动力0.31,均处于显著相关水平。各变量估计结果与理论预测和实际调查结果相符合,具有较强的解释力。     

基于农户生计演化的山地生态恢复研究综述

农户生计演化对山地生态系统恢复的影响是恢复生态学和乡村地理学关注的焦点。针对该学术背景,论文对国内外相关研究进行了总结,系统梳理了农户生计变化的内涵、驱动因素及其对山地生态系统恢复的影响;得出农户生计变化与山地生态系统演化是紧密相关的,农户生计状况最终决定着山地生态系统的特征,农户生计的改善往往驱动着山地生态系统的正向演替。最后,针对当前的研究和实践现状,建议进一步加强对农户生计和生态恢复相互关系的研究;针对当前的新农村建设和环境保护项目,要深入探究其对农户生计乃至山地生态系统恢复的影响;并建议优化中国地方官员考核标准,增强各级部门对农户生计以及环境保护的重视。     

我国西南三市家庭灰尘重金属水平及差异

以西南3个省会城市(直辖市)贵阳、南宁和重庆为研究对象,研究城市家庭灰尘中Ca、Fe、Cd、Cr、Cu、Ni、Pb和Zn的含量及累积状况.结果显示3个城市的家庭灰尘中Ca、Fe含量的空间变异度较小,其他元素空间变异度较大.贵阳与重庆家庭灰尘重金属水平较为接近,南宁相对略低.贵阳市家庭灰尘中Ca(10.1%)含量高于南宁市,Cd(1.18mg/kg)、Cu(207mg/kg)、Ni(87.3mg/kg)和Pb(259mg/kg)含量均高于重庆市和南宁市,其中贵阳市家庭灰尘中Ca、Cd和Cu含量显著高于南宁市.与3城市土壤重金属背景值相比,6种有毒重金属中,Zn、Pb和Cd在家庭灰尘中累积相对较重;3城市中,南宁市家庭灰尘重金属累积相对较重;贵阳、南宁和重庆家庭灰尘重金属累积较重的元素分别是Zn和Pb、Zn和Pb、Cd和Zn.     

Recycling behaviour and attitude: the case of the Hong Kong people and commercial and household wastes

The increasing environmental awareness caused by the green movement has led to changes in attitude towards our traditionally wasteful society. Recent surveys in Hong Kong have shown that waste recycling has gained increasing verbal support among its citizens. This paper reports on recent findings which reveals that some discrepancies exist between people's attitude and behaviour towards waste recycling. The implication of this phenomenon on how and when a waste recycling policy should be carried out is considerable. Two major types of barriers to waste recycling and reduction were evident. Technical barriers to recycling included lack of appropriate information, lack of conveniently located bins and of temporary storage space, whilst the most critical barrier to paper waste recycling was the presence of non-recyclable materials in some paper items. Psychological barriers included the attitude of being troubled, and that too little waste was involved to be worth the effort. Technical barriers were found to dominate in commercial paper waste recycling, and can usually be overcome while psychological barriers were more significant in household waste recycling and are more difficult to solve. Thus, it might be concluded that, if a large scale household waste recycling programme were in place in Hong Kong, more effort should be devoted towards educating the public, to eliminate as many psychological barriers as possible. Findings from attitude surveys on recycling can provide valuable information for policy makers. However, a review of the literature indicates that findings from attitudinal and self-reported behavioural surveys may exaggerate the proportion of those who have a favourable attitude towards the surveyed subject matter. Thus, it is prudent for policy makers to consider the response rate of the surveys also.     

基于标准化降水蒸散指数的中国东部季风区干旱特征分析

研究基于标准化降水蒸散指数,采用0.5°×0.5°中国地面气温和降水数据集,通过分析东部季风区季节和年尺度干旱覆盖率、频率以及单位面积干旱强度,揭示了中国东部季风区1961—2013年干旱特征时空分布变化。研究结果表明：近20 a东部季风区干旱特征变化明显,特别是1997年之后东部季风区干旱覆盖率和单位面积干旱强度显著增加;东北地区、华北平原、黄土高原和西南地区干旱频率增加,高频率覆盖范围扩大明显;气象干旱极端危险区扩大。全球变暖背景下东部季风区干旱呈现出极端化趋势。     

PCR-DGGE研究青海农村户用沼气池微生物群落结构

采用变性梯度凝胶电泳(DGGE)分析技术,对青海农村户用沼气池内细菌及古菌群落结构进行分析.结果表明,沼气池含有丰富的细菌及古菌类群,且泥样间的细菌和古菌的群落结构存在差异.4个户用沼气池发酵系统中,细菌分属于5个门,优势类群为拟杆菌门(Bacteroidetes)、厚壁菌门(Firmicutes)和变形菌门(Proteobacteria).在属分类水平上,属于24个类群,最优势类群为理研菌科佩特里单胞菌属(Petrimonas)、假单胞菌属(Pseudomona)、泰氏菌属(Tissierella)和梭菌属(Clostridium).同时,沼气池发酵系统中古菌主要包括热丝菌属(Thermofilum)、甲烷短杆菌属(Methanobrevibacter)、甲烷囊菌属(Methanoculleus)、产甲烷菌属(Methanogenium),其中,Methanobrevibacter和Methanogenium是沼气池内最优势的产甲烷菌.说明沼气池的产甲烷途径主要是氢营养代谢类型,水解、酸化过程主要由来自动物消化系统内的细菌完成.     

Capital assets framework for analysing household vulnerability during disaster

This paper examines the vulnerability of households to disasters, using an asset vulnerability framework to represent livelihoods. Such frameworks are widely employed to analyse household poverty and focus on living conditions and well-being rather than money-metric measures of consumption and income. The conceptualisation of household vulnerability is a challenge in current studies on coping with disasters. The paper considers whether a capital assets framework is useful in identifying and assessing household vulnerability in the context of the Wenchuan earthquake in China in 2008. The framework has five categories of assets (financial, human, natural, physical, and social capital) and attempts to measure the resilience and vulnerability of households. When applied to a major disaster, asset-based methods face the problem of heterogeneity of the population, such as with regard to livelihood type or residence. Moreover, the effect of external interventions, such as the provision of relief assistance, must be taken into account.     

Soil Contamination by Pb, Zn and Cn from a Lead Smeltery

In the environment of a lead smeltery contamination with lead, zinc and cadmium was measured over a 15-year period. Efficient bag filters were installed in order to remove dust from the flue gases. This measure of improvement resulted in a drastic reduction of lead, zinc and cadmium content in suspended particles (by 92, 94 and 89%), to a lesser extent in depositions (by 79, 75 and 68%), whereas in household dust the reduction was considerably lower (by 53, 55 and 70%). It can be assumed that household dust contains also redispersed soil particles on which the dust from the smeltery flue gases has deposited over years. To determine to what extent contaminated soil continues to cause increased population exposure directly or through plants or pastures, in the period 1981–1985 the content of metallic ions in the soil was measured at three depths. Selective solubility of soil metallic compounds was analysed in water, in 1 mol ammoniumacetate solution and in 0.05 mol ethylenediaminetetra-acetic acid (EDTA) solution in relation to their solubility in suspended particles, depositions and household dust. A considerably low portion of soluble metallic compounds was found in the soil and physico-chemical characteristics of the soil and portion of metallic ions bound to fulvice and humic acids were determined. The behaviour of metallic ions in contact with soil samples was studied in laboratory and it was found that approximately 50% of lead, 70% of zinc and 7% of cadmium ions change into non-soluble or poorly soluble compounds. By qualitative phase analysis in the non-soluble fraction PbO₂, Pb₃P₄O₁₃, Zn(OH)₂, ZnO, Fe₂O₃ and Cd(OH)₂ were identified.     

高校生活垃圾分类回收及资源化探讨

本文通过对高校生活垃圾组成的调查,探讨了教学区、宿舍区、食堂等区域生活垃圾的分类回收模式,并对废纸、废塑料、废金属、废电池、餐厨垃圾等资源化利用的可行性进行了分析,建议通过加强宣传工作,健全管理机制,完善资源化市场体系等途径对高校生活垃圾进行分类回收及资源化。     

中国农户耕地资源利用及效率变化的研究

根据两个时期农户资料的比较,对近1个世纪以来中国农户的耕地利用及效率变化进行了分析.农户耕地利用方面主要分析了户均耕地面积、耕地的细碎化、复种指数、种植结构及集约度等的变化;效率方面主要分析了农户的耕地生产率及农业劳动生产率的变化.结果表明,与80年前相比,目前我国农户户均耕地面积仅为当时的30%左右,但土地生产率却提高了2～4倍,农业劳动生产率提高了3倍以上.农业生物化学技术的进步及广泛应用是农业生产率提高的最重要原因.因此,我国的农业发展应该进一步重视生物化学技术的应用,重视能够保证生物化学技术得以实施的基础设施和基本条件的建设.同时,我们也应该考虑边际报酬递减规律的作用,在一些生物化学技术的边际报酬已经相当低的地区,要进行制度创新,通过规模的扩大来获得规模经济,进一步发挥机械技术的作用.