TECHNOLOGICAL CHANGE AND SURPLUS LABOUR IN EGYPTIAN AGRICULTURE, 1952–1972

This paper has two main purposes. First to determine if technical innovation has occurred in Egyptian agriculture and whether or not it has been labour-using in nature. Secondly, to determine whether or not the marginal product of labour in Egyptian agriculture has been negative (surplus labour). The time period covered by the study is 1952 to 1972. The above objectives were met by estimating a weak disposability of inputs (WDI) production function. The characteristics of the weak disposability of inputs function were discussed in great detail, since much of the profession is unfamiliar with this functional form. The function was then estimated and the results seemed to indicate that this functional form was appropriate for Egyptian agriculture. The results of the estimation process indicated that labour-using technical innovation had indeed occurred, although at a very slow rate. In addition, for most of the time period covered the marginal product of labour was indeed negative.     

Multi-period stochastic optimization of a sustainable multi-feedstock second generation bioethanol supply chain − A logistic case study in Midwestern United States

This work proposes a multi-objective optimization model to design a sustainable multi-period second generation biomass-to-bioethanol supply chain under multiple uncertainties. The objective is to simultaneously maximize the economic, environmental, and social performance. The strategic decisions such as land allocation for switchgrass cultivation, biorefinery locations and capacities, and the biomass-to-bioethanol conversion pathway are determined for each planning period which are staggered across the entire planning horizon. The augmented ε–constraint method is used to trade-off among the competing objectives and to obtain feasible solutions that achieve desired levels of sustainability. In order to solve the proposed stochastic optimization model efficiently and effectively, this work proposes a solution approach involving sequential application of a modified Sample Average Approximation method and Benders decomposition. A case study is presented to demonstrate the effectiveness of the proposed mathematical model and its impact on land usage and sustainability.     

Accounting for farmers’ production responses to environmental restrictions within landscape planning

Environmental planning aims to safeguard and foster the ecological functionality of agricultural landscapes. In order to reach a sustainable development of agricultural landscapes, in addition to ecological objectives socio-economic ones also need to be considered. In this context, the authors draw attention to three points. First, whenever ecologically sensitive areas (“ecological sites”) are used for agricultural production, it is necessary to take account of the fact that farmers tend to adapt to environmental requirements by production responses outside the ecological site itself. Second, in order to identify the socially most “desirable” land-use responses it is necessary to supplement the above-mentioned environmental objectives by socio-economic ones. Third, when choosing an appropriate model for such multi-criteria decision analysis, the question of substitutability between criteria is of utmost importance. The paper discusses the above-mentioned issues against the background of a case study of environmental planning for an ecologically very valuable agricultural landscape in Germany, the Bayerisches Donauried. Two models of multi-criteria decision analysis (MCDA) are applied, one based on the “single synthesizing criterion” method, and the other one based on the “synthesis by outranking” method. The models serve to evaluate four different land-use options, using criteria mainly derived from landscape functions and weights gained from interviews with major stakeholders. The paper presents the models’ results concerning the ranking of the different land-use options and discusses the implications for agri-environmental policies and rural development planning.     

TECHNOLOGY CHANGE AS AN INSTRUMENT IN AGRICULTURAL DEVELOPMENT

The introduction of new technology into agriculture is a central feature of development schemes, but is regularly criticised because of its distributive effects. Technology change is unavoidably biased, however, and cannot easily be used to serve specific distribution objectives. Ex post studies do not necessarily guide the appropriate choice of technology as they rarely offer causal explanations. Predicting the consequences of innovation is hampered by the narrowness of established economic models and the conceptual indefiniteness of technology as a variable in those models. In the absence of a wider system framework, technology for development is selected according to more general guides. These emphasise either the primacy of output objectives or advocate technology forms presumed appropriate to distribution objectives. Neither adequately substitutes for a broad framework to guide the choice of technology as an instrument in development.     

A NOTE ON LIVESTOCK BREEDING POLICIES IN STABLE AND DEVELOPMENT SITUATIONS

Multi-stage linear programming is used to develop sheep replacement policies in a number of different situations. Policies are developed for eight and sixteen year periods assuming, firstly a constant feed supply, and secondly, an increasing feed supply over the period. The results show the optimal flock composition together with the sheep sale activities for each year of the plan. The marginal value products indicate which constraints are the most important and whether any should be relaxed in order to make the model more realistic. It is concluded that it is not necessary to use a very long planning period in order to determine the activities for the early years. The results from the shorter planning period appear to be consistent with long-term goals.     

Efficiency in forest management: A multiobjective harvest scheduling model

This paper presents a new forest harvest scheduling model taking into account four conflicting objectives. The economic factor of timber production is considered and also aspects related to environmental protection. We also incorporate adjacency constraints to limit the maximum contiguous area where clear-cutting can be applied. The model proposed is applied to a timber production plantation in Cuba located in the region of Pinar del Río. One factor to be taken into account in Cuban plantations is that the forest has a highly unbalanced age distribution. Therefore, in addition to the classical objectives of forest planning, we have the objective of rebalancing age distribution by the end of the planning horizon. Explicitly, the four objectives considered in the model are: (a) obtaining a balance-aged forest; (b) minimizing the area with trees older than the rotation age; (c) maximizing the NPV of the forest over the planning horizon; and (d) maximizing total carbon sequestration over the whole planning horizon. The solution to the proposed model provides a set of efficient management plans that are of assistance in analysing the tradeoffs between the economic and ecological objectives. The model is also applied to randomly generated simulated forests to compare its performance in other contexts. As the problem is a multiobjective binary nonlinear model, a metaheuristic procedure is used in order to solve it.     

国土空间规划的立法统合及其表达

研究目的：通过梳理国土空间规划立法的不同类型,比较和分析适合中国现阶段发展需要和制度基础的国土空间规划立法统合模式,为研究制定国土空间开发保护的总体性法律探索可行进路。研究方法：规范分析法、文献分析法。研究结果：国土空间规划的体系化、法治化和制度化离不开立法统合,但是现行国土空间规划分散立法模式存在现实局限性,无法回应“国土空间开发保护总体性法律”这一根本要求。结合中国国土空间规划发展的阶段性和既有立法的制度基础,适度法典化是目前国土空间规划立法统合更为合适的路径选择。研究结论：（1）在制度特征上,寻求开放性与封闭性、稳定性与回应性、调适性与渐进性的适度均衡;（2）在立法形式上,初期阶段通过制定《国土空间规划法》凝练共识规则和一般原则,在法典化时升级为《国土空间规划基本法》;（3）在体系衔接上,合理衔接与宪法以及其他部门法之间的关系,形成科学的体系划分。     

Planning policy,housing density and consumer preferences

Due to a combination of government planning policies and market pressures in England in the period 2000–2008, there was an increase in the construction of flats and high-density developments and a decline in the construction of houses. In this paper, an analysis of the effects of these policy constraints is undertaken. Using hedonic pricing models, we test for a non-linear relationship between house prices and residential density in England. Consumers prefer houses over flats and detached properties over semi-detached and terraced (i.e. lower density suburban areas). However, both low-density, detached-dominant areas and high-density, flat-dominant areas attracted a premium over medium density areas and the relative size of these price differences vary between different housing market areas. In cities outside London, we consistently see a convex relationship between price and density, whereas a concave relationship between price and density is consistently observed in London. This suggests a different form of relationship between density and house prices in large urban conurbation areas, compared to more typical provincial cities. The conclusions we draw are that in the correct context, high density may be viewed positively but a single planning policy is not appropriate and it should be tailored to suit local market needs.     

水利风景区的旅游开发和规划若干问题

从水利风景区的特殊性入手,讨论水利风景区规划的原则和要求、内容和深度、规划成果的审查与实施等问题。认为水利风景区旅游开发规划的时序安排必须与水利工程建设规划相衔接,尤其新建设的水利工程设施,最好在工程施工之前就考虑旅游开发问题,把施工期间的建筑物、管网和道路等与后期的旅游需要融合起来,以节省投资,提高设施的利用率。     

新时期住房发展规划指标体系构建研究--以上海为例

文章基于我国主要城市和国外发达城市住房发展规划指标体系构建的经验和方法,结合上海住房发展面临的机遇和挑战,回顾历年来上海市住房发展主线,在代表性、层次性、易操作性和稳定连续性原则下,构建新时期上海住房发展规划指标体系,对指标体系的构建方法和内容进行了探索。文章首先通过频度分析初步建立由常规性指标、阶段性指标和个性化指标组成的指标库;其次以目标为导向从指标库中遴选贴合上海实际的指标,补充体现上海住房发展特征的指标,形成指标集合;最后以实施为导向建立起规划目标、指标、主要任务和策略之间相互联系,兼顾刚性控制和弹性引导的指标体系。     

Goal Programming: Potential and Limitations for Agricultural Economics

Recently, goal programming (GP) has been discussed in the literature as an alternative to linear programming, particularly in decision-making environments involving multiple objectives. In this paper we present an overview of the different GP formulations, their assumptions, limitations, and implications for agricultural decision making. Furthermore, a new insight into the interpretation of duality in GP is discussed. The concept of "standardized dual variables" which provides a more meaningful interpretation of shadow prices in GP is introduced. A simple but realistic farm agricultural planning example is used to illustrate the analysis.
Récemment, la technique de programmation appellée "goal programming" ou "GP" a été presentée dans la literature comme une alternative à la programmation Iinéaire, particulièrement dans les situations òu le procés de décision est basé sur plusieurs objectifs simultanés. Dans cet article nous présentons une vue génerale des différentes formes de la "GP;" leurs hypothèses de base. Ieurs limitations, et leurs implications pour le procés de decision agricole, une nouvelle intérpretation de la dualité en "GP" est proposée. En particulier, le concept de "variables duales standardisées" est introduit, ce qui permet une interpretation plus significative des prix de reference en "GP." Finalement. un exemple simple mais réaliste de planification agrcole a l' échelle d' une ferme est pour élucider utilisé l' analyse.     

A spatial land-use planning support system based on game theory

Spatial urban land-use planning is a complex process, through which we aim to allocate suitable land-uses while taking into consideration multiple and conflicting objectives and constraints under certain spatial contexts. Landowners should be modeled as players that are able to interact with each other so as to seek their best land-uses while considering multiple objectives and constraints simultaneously. Game theory provides a tool for land-use planners to model and analyze such interactions.In this paper, spatial urban land-use planning is considered as a game to model local competitions between landowners, whose players (i.e. landowners) of which play to pick the most suitable land-use for themselves. The game is defined based on the objectives of consistency, dependency, suitability, compactness of land-uses, and land-use per capita demand. In this paper, three different scenarios are designed for the players. In the first scenario, the players are greedy and only accept the most compatible land-use. In the second scenario, conversely, the players are fully collaborative and care about other players’ payoff. In the third scenario, the players are first greedy, but when they cannot achieve an agreement with other players, they change their attitude to become gradually collaborative for reaching the Nash equilibrium (NE). Furthermore, the dissatisfaction index (DI), which represents the number of unsatisfied landowners with their current land-use, is defined to compare the different scenarios. The proposed model is tested in a district located in District 7 in Tehran (the capital city of Iran) with 2710 parcels.Results of the first scenario showed that, at the beginning of the game, 50 % of the landowners were not satisfied with their current land-uses, but after 50 iterations, about 100 landowners were dissatisfied with their land-use and this scenario was not able to reach the NE. Results of the second scenario indicated that, in order to reach an optimized layout, 325 parcels needed to be changed. Also, after reaching the NE in this scenario, values of the objective functions did not significantly improve. So, lowering the expectations of the players would not lead to appropriate results. The outcomes of the third scenario provided appropriate results, which could be achieved when the expectation levels of the players could be changed during the game. Furthermore, the NE was obtained among the players and the objective functions improved by 20 % on average in comparison with the other scenarios.Moreover, results of the scenarios were compared with the optimized layout obtained by a genetic algorithm (GA) using different parameter values. Results of the comparison also revealed that the urban layouts produced by game theory improved the objective function values obtained by the GA in about 10 % and improved the GA’s running time in more than 85 %, on average in this research.     

Evaluating Environmental Risks Using Safety-First Constraints

This paper incorporates an upper partial moment concept into a linear programming model to impose safety-first environmental constraints. The model is linear and deterministic, treats a discrete sample as an empirical distribution, and optimizes over the column space. It allows a decision maker to specify the objectives and the compliance probabilities with the objectives when making decisions, and endogenously determines the risk levels. Even though it is presented in the context of environmental management, the model is general enough to be extended to other situations where the probability of a variable exceeding some target or standard is restricted.     

RESOURCE MANAGEMENT,SUSTAINABILITY AND PROPERTY RIGHTS IN NEW ZEALAND*

Sustainable land management objectives in New Zealand have recently been redefined in the Resource Management Act 1991. The new legislative framework can be viewed in part as an adjustment in existing property rights to meet resource use externalities. An understanding of the structure and characteristics of property rights in land clarifies a number of issues in the area of economic efficiency and administrative practicality, and focusses on areas where appropriate solutions to externalities may be difficult to achieve.     

DYNAMIC FARM—LEVEL PLANNING MODEL FOR BEEF FEEDLOT PRODUCTION AND MARKETING

The study is aimed at formulating and empirically applying a dynamic farm-level model for the planning of optimal beef feedlot production and marketing strategies. A dynamic programming (DP) model is used to calculate the optimal feeding schedule (i.e. liveweight gain sequence), market liveweight and stock replacement for a single bull calf over a one-year planning period, taking into account seasonal fluctuations of planning parameters such as beef prices, feeding costs, nutritional requirements, and stock replacement costs and obtainability. The DP model includes a linear programming (LP) subroutine for calculating least-cost feed rations. The planning model is empirically applied using data and assumptions representative offeedlots in the Coastal Plain region of Israel where most feedlot production and marketing decisions are made by ‘rule-of-thumb’ using set liveweight gain sequences, market standards and stock replacement decisions. The empirical findings indicate that the profitability of feedlot production and marketing could be increased by an average of 10% over that obtained from ‘rule-of-thumb’ decision rules.     

土地利用规划中人口预测模型的比较研究

研究目的:研究土地利用规划中几种常用人口预测模型的特点和适用条件,为土地利用总体规划编制工作服务.研究方法:统计分析法和对比分析法.研究结果:利用人口历史统计数据建立预测模型,分时段进行预测,并与实际观察值比较,得出预测误差的大小,通过预测误差大小的分析比较,总结了各种预测模型的特性与适用条件.研究结论:一元线性回归法适用于数据直线趋势较明显的预测;历史数据较少时,可用指数平滑和移动平均数法;数据情况复杂时可采用GM(1,1)模型法;自然增长率等资料准确可靠时可采用人口自然增长法或马尔萨斯法;宋健模型法用于短期预测的精度较高;土地规划中人口预测应多种预测方法综合运用.     

Appraising Alternatives for Allocating and Cost Recovery for Irrigation Water in Egypt

Alternative approaches to allocating and recovering costs for water on Egyptian farms are proposed and evaluated in accordance with the societal objectives of allocative efficiency, equity of income distribution and cost recovery. A linear programming model of a study area in Egypt's northern Delta predicts farmers' response to the proposed cost-sharing instruments over a range of water supply conditions. Transactions costs for each charging instrument are estimated and incorporated into the allocative. efficiency analysis. Flat land charges, supplemented by water quotas in the event of increasing water scarcity, best achieve societal objectives in the current and prospective Egyptian situation. Volumetric charging instruments were judged to be somewhat less desirable, due to higher tangible and intangible costs of implementation. The results highlight the importance of transactions costs, the degree of water scarcity and other governmental revenue raising policies in determining an appropriate charging mechanism.     

Transitional pathways towards input reduction on French field crop farms

In order to maintain their income, using European Union grants, mountain livestock farms need to have a production plan based on animal production and environmental objectives. To help farmers to do this, we develop a method allowing the evaluation of land management strategies that are compatible with both objectives. The strategies set up by farmers were examined from four aspects: forage production to feed livestock, grassland sustainability, avoiding dominance of invasive species and enhancing species diversity, and field characteristics which restrict the range of possible uses. Using this method on four suckling cow farms in the Central Pyrenees (SW France), chosen from 40 farms differing in stocking rate per ha and on their ability to grow their own forage, we identify three land management strategies differing in their balance between animal production and grassland improvement objectives. The first and second were focused on animal production and land sustainability, respectively. The third is a compromise between the two objectives. We show that the relative importance of planning and monitoring rules differed for the three strategies. For the first, the planning process is very important, whereas there is not much monitoring required. The converse is true for the other strategies.     

矿产资源规划环境影响评价研究

矿产资源规划是矿产资源勘查开发和利用的指导性文件,是依法审批和监督矿产资源勘查的主要依据。矿产资源规划环境影响评价主要包括:规划的协调性分析、确定合理的环境目标和评价指标、规划实施后的环境影响预测与分析、规划方案优化调整建议;矿产资源环境影响评价方法包括:政策实施分析方法、项目环境影响评价方法以及一些修改的项目环境影响评价方法、信息技术方法当前流行的一些专业性评价方法,如数学模型法和专家评判法等。     

广西耕地资源变化与粮食安全分析

在详细分析2000—2008年广西耕地变化趋势及造成耕地减少原因的基础上,采用最小人均耕地面积及耕地压力指数等方法,对粮食安全状况进行了研究,同时详细分析了工业化发展所处阶段及经济发展与耕地资源变化之间的关系,并结合广西新一轮土地利用总体规划预测的社会经济发展目标,运用统计分析方法预测了2020年耕地保有量。结果表明,广西2000-2008年粮食生产处于供不足需的状态,且处于工业化初期阶段,其工业化发展及城镇化的提高是建立在耕地资源的占用之上。