以农村阶层分化为基础的土地保障研究

在农村社会保障尚不完善的条件下,土地除了充当生产要素外,还发挥着对农村居民的生活保障功能。制定土地乃至农村各项政策时必须考虑到土地的保障功能,这关乎到整个农村社会的稳定。文章试图利用贺雪峰提出的五个农村阶层分析土地对于各个阶层不同的重要程度及保障作用,并在此基础上针对各个阶层提出有关土地及社会保障的建议,以满足农村不同阶层差异化的保障需求。     

论我国食品安全监管体制的完善

食品安全问题的日益严重,引发国人的极度关心。问题的频发表明我国食品安全监管执法体制还存在不少漏洞。其问题主要是：事前监管缺乏科学性、事中监管缺乏有效性、事后监管缺乏及时性、可追溯性。因此食品安全监管事前必须要建立合理的食品安全标准,严格食品行业准人标准;事中应完善食品生产经营过程监管,提高食品安全检验水平;事后要建立政府问责机制,加大对食品生产者违法行为的惩罚力度,完善社会监督机制。     

Measuring Farm and Market Level Economic Impacts of Improved Maize Production Technologies in Ethiopia: Evidence from Panel Data

While it is often recognised that agricultural technology adoption decisions are intertwined and best characterised by multivariate models, typical approaches to examining adoption and impacts of agricultural technology have focused on single technology adoption choice and ignored interdependence among technologies. We examine farm‐ and market‐level impacts of multiple technology adoption choices using comprehensive household survey data collected in 2010/11 and 2012/13 in Ethiopia. Economic surplus analysis combined with panel data switching endogenous regression models are used to compute the supply shift parameter (K‐shift parameter), while at the same time controlling for the endogeneity inherent in agricultural technology adoption among farmers. We find that our improved technology set choices have significant impacts on farm‐level maize yield and maize production costs, where the greatest effect appears to be generated when various technologies are combined. The change in maize yield and production costs results in an average 26.4% cost reduction per kilogram of maize output (the K‐shift parameter). This increases the producer and consumer surpluses by US$ 140 and US$ 105 million per annum, respectively. These changes in economic surplus help to reduce the number of poor people by an estimated 788 thousand per year. We conclude that deliberate extension efforts and other policies that encourage integration of technologies are important for maize technologies to yield their full potential at both farm and market levels.     

Assessing the Reliability of Self‐reported Income Information in Informal Small Business Lending through a Bogus Pipeline Experiment

Coping with asymmetric information plays a major role in successful small business lending. Our purpose is to determine if small business applicants report their income information correctly when requesting a loan. We use a randomised controlled trial bogus pipeline experiment, established during a typical cash‐flow analysis of a bank for small businesses in the Philippines. The bogus pipeline approach is commonly applied in social science and aims to increase the rate of truth telling by informing participants that answers will be verified by a lie detector. The experimental data, which include 243 observations of credit clients that are mainly from the agricultural and food value chain, served to identify asymmetric information. Additionally, debtors’ repayment behaviour for approved loans was observed by the bank. Our results indicate that loan applicants of the treatment group report lower incomes, an effect which is most pronounced in lower income quantile. Our analyses also reveal higher loan delinquencies in the control group.     

闽侯县闲置农地生态安全评价研究

[目的]根据闽侯县农用地闲置情况,结合当地社会经济及生态环境发展情况,深入分析闽侯县闲置农地的生态安全发展水平。[方法]建立闽侯县闲置农地生态安全评价指标体系,分别从农村垃圾处理点数量、财政支农资金、外部进入农村投资、农业生产总值、种粮补贴、自然灾害、农业技术水平、农村生物的多样性程度、农村家庭收入结构、农村生态补偿金额、农地的整理规模及环保支出占GDP比重共确定12个指标进行深入研究,运用普通最小二乘法对设计的多元线性回归模型进行回归,进一步对闽侯县闲置农地的生态安全水平进行评价。[结果]农村垃圾处理点数量、财政支农资金、种粮补贴、环保支出占GDP比重、生态补偿金额、生物多样性程度对闽侯县闲置农地生态安全水平起到促进作用,呈正相关趋势;自然灾害则与闲置农地生态安全水平呈负相关趋势。[结论]整体看来,闽侯县闲置农地的生态安全水平主要受到当地经济、环境及生态基础三大因素的影响。     

土地经营规模对农户种粮收入的影响分析——以吉林省公主岭市为例

土地是财富之母,土地作为农民进行农业生产的基本生产资料,是农民收入来源的重要依托。家庭联产承包责任制实施至今虽然取得很大成就,但是以家庭经营为主的传统经营方式弊端日益显现,农民种粮收入难以实现有效增长。[目的]为了达到农村土地适度规模经营,调整农村产业结构、促进农民增收、加快小城镇建设等目的。[方法]通过选取产粮大县公主岭市为研究对象,利用实地调研数据对不同土地经营规模下的种粮成本及利润水平进行比较,并运用c-D生产函数对数据进行多元线性回归分析。[结果]从种植成本来看,5~20hm~2中等经营规模投入的综合成本低于5hm~2以下小规模和20hm~2以上大规模经营;从利润来看,5~20hm~2中等经营规模无论是自有承包地还是转包地所获得的每667m~2平均利润均高于小规模和大规模的经营规模。[结论]公主岭市农户土地经营面积为5~20hm~2的中规模优于其他土地经营规模。同时运用多元线性回归模型分析其对农户种粮收入的影响程度,进一步证实土地经营规模对农民种粮收入具有积极促进作用。从而提出推进公主岭市土地适度规模经营的对策建议。     

Is late really better than never? The farmer welfare effects of pineapple adoption in Ghana

Export agriculture offers potentially high returns to smallholder farmers in developing countries, but also carries substantial market risk. In this article we examine the intertemporal welfare impact of the timing of a farmer's entry into the export pineapple market in southern Ghana. We examine whether farmers who never cultivated pineapple are better or worse off than farmers who decided to adopt pineapple earlier or later relative to their peers and experienced a significant adverse market shock several years prior to our endline survey. We use a two‐stage least squares model to estimate the causal effect of duration of pineapple farming on farmer welfare. Consistent with economic theory, we find that earlier adoption of the new crop brings greater welfare gains than does later uptake. But we find that the gains to later uptake of pineapple—just before the market shock—are small in magnitude, just 0.1 standard deviations of a comprehensive asset index, indicating that the gains to adoption may be precarious and depend on the context, in particular on the severity of prospective market shocks.     

坚持科学发展观 创建社会主义现代国有林场——关于国有林场建设发展长远目标定位问题的思考

分析了国有林场建设发展无长远目标所导致的“边缘化”状况,论述了确立国有林场建设发展长远目标的必要性和紧迫性;提出了建设社会主义现代国有林场的六项基本内容和要求;认为建设社会主义现代国有林场需要解决建设规划林场体制、投资政策、人才队伍建设等问题。     

对LZ77图象压缩算法进行改进的C语言实现

本提出了一种用于无损灰度图象数据压缩新的编码方法-一种基于对LZ77压缩方法的改进以及对图象元素预测误差的估计为基础的字典压缩方法,并给出了该方法的C语言程序实现。     

基于L频段数字航空通信系统1的F-OFDM波形设计

随着航空飞行器种类和数量的激增以及第五代（5G）移动通信系统和物联网（IoT）时代的到来,下一代航空无线通信系统面临着高安全性、大传输容量、低延时、强鲁棒性、高灵活性和综合业务提供等新的挑战。为此,提出了一种基于L频段数字航空通信系统1（L-DACS1）的滤波正交频分复用（F-OFDM）波形设计方法并探讨了可能的技术演进路径。首先引入了认知无线电、非连续载波干涉码OFDM和滤波器的思想,然后针对不同航空飞行器用户动态自适应配置波形参数。仿真结果表明,该方法得到的系统波形具有较低的带外辐射功率、优良的块误码率性能和较高的吞吐量增益。