从商人、外交官到收藏家—乌利·希克的“麻将”

当代艺术圈很少有人不知道乌利·希克。乌利·希克有着许多身份,他的过去也已广为众人所知:他在1 979年以商人的身份首度来到中国,代表讯达公司(Schindler)成立了第一个在     

需高度警惕中国资本外逃现象

刘永刚在2012年第7期《中国经济周刊》撰文说，发生在中国的资本外逃现象已经成为既定事实，并且这种现象正在对处在上升期的中国经济产生潜在的风险。我国的移民当中，约有80％的人并不是为了离开中国，他们只是为了换取一个身份。在这些人看来，获取收益的最佳地点仍然在中国，而移民则是为了将钱放在一个他们认为更安全的地方。这种现象就需要我们思考：     

鳄龟的室内——池塘两段养殖法

<正> 鳄龟又称肉龟、小鳄龟、蛇鳄龟等,以其出肉率最高(85%—89%)而闻名于世。自从美洲引进后经几年的试养实践,因集观赏、食用、滋补、药用多种功能于一体而走俏海内     

农村社会阶层正在发生的微妙分化

二十多年来，中国的改革开放使农村发生了一个重要的变化，也就是对我国在改革前形成的、以身份为划分标准的世袭性就业体系的冲击和撼动，但仍没有彻底改变这个体系：一方面改革开放确实给了农民自主选择职业的机会和权利，但另一方面，农民的身份因素(特别是户籍身份)仍然在影响和制约着农村劳动力的流动。     

贫困人口反弹的背后

《瞭望》新闻周刊发表文章称，中国已经进入安全生产事故的多发期。文章说，通过对一些国家安全生产形势的分析，人均国内生产总值(GDP)1000～3000美元这个区间，是公共安全事故的高发期。中国目前正处在这个阶段。     

农民人数不是统计问题

中国究竟有多少农民？9亿？还是8亿、7亿？ 这似乎是一个简单的统计问题，甚至只是个数学问题。但是，一个不能忽略的背景是，在社会快速转型期，不少农村人员的身份处在转换之中，我国到底按什么口径计算农民或农村人口，人数到底是多少，其说不一。     

鳄龟周年生态养殖技术

<正> 鳄龟又称小鳄龟(以别于大鳄龟)、蛇鳄龟等,因其出肉率高达85%—89%,又称肉龟而闻名于世。自从美洲引进经过6年试养证实,因集观赏、食用、滋补和药用等多种功能于一体而走俏海内外,每公斤售价达800元还有价无货。     

关贸总协定对我国农产品的冲击及策略研究

“关税及贸易总协定”简称关贸总协定(GATT),在国际上还被称之为“经济联合国宪章”。目前,总协定缔约国(方)已有近110个国家(地区),还有30多个非缔约国派有观察员。缔约国(方)之间的贸易额占世界贸易总额的85％以上。关贸总协定的多边贸易规则正日益成为世界各国普遍接受的共同准则,而与世界银行、国际货币基金组织一道成为调节世界经济关系的三大支柱。关贸总     

角色差异与认同迷惑:网络话语中的农民形象分析——以网络事件“不嫁(娶)农村人”为例

本文以网络事件"不嫁(娶)农村人"为研究对象,选取其中几则典型帖文为具体分析案例,从城乡婚姻观的视角分析了蕴含于中国社会几十年的城乡差别、农民身份认同和农民形象的塑造传播等问题。研究发现,"不嫁(娶)农村人"问题从一个真实的、日常生活的层面蕴含着民族心态、国家历史和国家政策的重大主题,表现了农民这一重要阶层所蕴含着的真实性格的张力、隐密话题的活力与弱者武器的韧性,进一步揭示出当代中国城市化进程中农民身份转变与传统婚嫁观念变迁的时代之惑。     

关于当前农垦工作中值得重视的几个问题

关于当前农垦工作中值得重视的几个问题○陈欣成我国农垦事业的发展正处在一个承前启后、继往开来的重要时期，要实现农垦经济与社会发展“九五”计划与２０１０年远景规划目标，需要我们继续发扬“艰苦奋斗，勇于开拓”的农垦精神，脚踏实地地去做大量卓有成效的工作。我...     

USGS"2000世界油气评价"待发现油气资源预测法

美国地质调查局 2 0 0 0年的油气资源评价中 ,主要进行了两个方面的预测 :待发现油气资源预测和储量增长预测。待发现油气资源的预测主要运用了油气藏规模分布预测方法及蒙特卡洛模拟方法。     

20世纪中期关中地区的土地问题 --以高陵县通远乡为例

本文通过对土地改革前后高陵县通远乡的土地状况的个案分析，论证了正是因为关中地区人地关系的宽松，租佃关系不普遍，地主和富农拥有的土地不多，结果在土地改革期间，关中地区可供分配的土地比较少，当地政府无法同时做到既完全贯彻中央精神，又充分考虑到地方实际情况，最终在实际执行中，导致了中央政令与地方具体实践在一定程度上的背离；而就产中地区的土地改革本身而言，其效果是不经济的。     

Editorial - Multiple-use forestry

The problem of multiple-use forestry arises because (1) a forest can be managed to provide a wide range of products and services, (2) the different uses are not perfectly compatible with each other, and (3) some products are not priced in markets and many of the services a forest provides have the characteristics of public goods. Examples of major forest products include, in addition to timber, edible berries, fungi, and hunting games. Forests also provide recreation opportunities and various environmental services (such as regulating local climate, reducing soil erosion, reducing pollutants in the atmosphere, regulating the global climate, providing habitats for wildlife, etc.). The outputs of nontimber goods in general depend on the quantity and structure of the forest, which can be changed by various forest management activities. However, a forest state most suitable for the production of one good is usually not optimal with respect to another good. Typically, there does not exist a set of management activities that simultaneously maximize the outputs of timber and all other goods.Another way to understand the conflicts between different uses is to view standing timber as an intermediate product of forestry investment, which is employed as an “input” for the production of timber products and nontimber goods. Thinking in this way, the conflicts arise partly because timber production and nontimber uses compete for the same input, and partly because of the differences in the “production technology” among different nontimber goods. A change in the standing timber may have positive impacts on some nontimber uses, but have negative effects on others. Because of the conflicts among different uses, it requires that both timber products and nontimber goods should be explicitly incorporated into forestry decision-making in order to achieve the greatest benefits to the forest owner and/or the public.Most of the economic analyses of multiple-use forestry decisions have explicitly or implicitly adopted the view that multiple-use should be achieved in individual stands. Each stand should be managed to produce an optimal mix of timber products and nontimber goods. Another view of multiple-use forestry is to manage each stand for a primary use, whereas multiple-use concerns are addressed by allocating different stands in a forest to different uses. A general argument in support of the primary-use view is that specialization makes for efficiency. The production of timber and nontimber goods is a joint process, however. Strictly speaking, one cannot separate timber production and the production of different nontimber goods. For example, managing a stand for timber production does not exclude the possibility of producing some nontimber goods in the stand. Since every stand usually produces more than one product, efficient multiple-use forestry requires that each stand should be managed for an optimal mix of timber and nontimber outputs. On the other hand, it may well be the case that the optimal multiple-use mix for a particular stand consists of a maximum output of one product. In this case the optimal multiple-use management decision would coincide with the optimal decision pertaining to a single use. In other words, it may be optimal to manage a particular stand for one primary use. Using the terminology of economics, primary-use may be efficient for stands in which the multiple-use production set is nonconvex. Recent research has explored several sources of nonconvexity in the multiple-use production set. However, there is no evidence supporting the argument that specialization is always more efficient than multiple-use management of individual stands. From an economics viewpoint, efficient primary-use is special cases of multiple-use stand management.A widely recognized limitation of multiple-use stand management is that, by considering each stand separately, one neglects the interdependence of nontimber benefits and ecological interactions among individual stands. The nontimber benefits of a stand depend on the output of nontimber goods from other stands. Likewise, the nontimber output from one stand affects the value of nontimber goods produced in the other stands. Ecological interactions among individual stands imply that the output of nontimber goods from two stands in a forest differs from the sum of the outputs from two isolated stands. These interdependence and interactions imply that the relationship between the nontimber benefits of a stand and the stand age (or standing timber stock) cannot be unambiguously determined - it depends on the flow of nontimber goods produced in the surrounding stands. Therefore, it is improper to determine optimal decisions for the individual stands independently. In stead, efficient multiple-use forestry decision should be analyzed by considering all the stands in a forest simultaneously.Another serious limitation of multiple-use stand management is that each stand is treated as a homogenous management unit to be managed according to a uniform management regime. One implicitly assumes that the boundaries of each stand is exogenously given and will remain unchanged over time. This assumption imposes a restriction on the multiple-use production set, thereby creates inefficiency. As an example, consider a large stand with a nonconvex production set. It may be possible to eliminate nonconvexity in the production set and push the production possibility frontier outwards by dividing the stand into several parts and managing each part for a primary-use. It may also be efficient to combine two adjacent stands into one to be managed following a uniform regime, because of the presences of fixed management costs, and/or because the relationship between some nontimber outputs and stand area is not linear.In contrast to income from timber production, nontimber goods produced at different time points are not perfect substitutes. The rate at which a forest owner is willing to substitute a nontimber good produced at one time point for that produced at another time point changes with the outputs of the nontimber good at the two time points. In general cases, the nontimber goods produced at one time point cannot be consumed at another time point, and the marginal utility of a nontimber good decreases when its output increases. This provides a motivation for reducing the variation in the output of nontimber goods over time. An effective approach to coordinating nontimber outputs over time is to apply different management regimes to different parts of a stand, or apply the same regime to adjacent stands, which would change the boundaries of the stands. Preserving the existing stand boundaries would limit the possibility of evening out the nontimber outputs over time, and thereby lead to intertemporal inefficiency in multiple-use management.In previous studies of multiple-use forestry decisions the nontimber outputs or benefits are usually modeled as functions of stand age or standing timber stock. Future flows of nontimber goods or benefits are incorporated into a stand/forest harvest decision model to explore the implications of nontimber uses for optimal harvest decisions. While stand age and standing timber stock may have significant impacts on nontimber outputs, other forest state variables, e. g. the spatial distribution of stands of different ages/species, may be of great importance to the production of nontimber goods. Recognition of such forest state variables could change the relationship between timber production and nontimber outputs and therefore change the optimal forest management decisions.In summary, multiple-use forestry is not simply an extension of timber management with additional flows of benefits to be considered when evaluating alternative management regimes. Recognition of multiple uses of a forest leads to two fundamental changes of the forestry decision problem. First, the optimal intertemporal consumption of forestry income is no longer separable from forest management decisions. In general, the optimal intertemporal consumption of forestry income depends on future flows of nontimber goods, implying that the consumption-saving decision should be made simultaneously with the decision on the production of timber and nontimber goods over time. Secondly, it is no longer appropriate to optimize the management regime for each stand separately. The nontimber outputs from a forest depend on the age distribution of individual stands, and on a wide range of other forest state variables such as the spatial distribution of stands of different ages and tree-species composition. Ecological interactions and interdependence among stands imply that management regimes for different stands should be optimized simultaneously. In addition to changing rotation ages and harvest levels, efficient multiple-use forestry requires optimizing the spatial allocation of harvests, redefining the boundaries of stands, coordinating the choices of tree species in regeneration of harvested area and so on.The lack of rigorous production functions for nontimber goods imposes a severe restriction on attempts to perform comprehensive economic analyses of multiple-use forestry decisions. This restriction in itself is no justification for ignoring many of the key aspects of multiple-use forestry problem and modeling the problem as one of determining the optimal rotation age or optimal harvest level. It requires that economic models of multiple-use forestry should be developed with special consideration of the vague and imprecise information regarding the relationships between nontimber outputs and forest state variables.Peichen GongDepartment of Forest EconomicsSE-90183 UmeåSweden     

我国农业大中型沼气工程发展现状、存在问题与对策措施

该文分析了我国处理农业废弃物大中型沼气工程建设数量、产气量、区域分布及沼气工艺类型等方面的发展现状,总结了我国沼气工程发展中存在的主要问题,提出了加快我国大中型沼气工程发展的对策措施。     

可持续发展的实质——建设资源节约型社会

我国正面临着日益严峻的资源紧缺形势.严峻资源形势呼唤资源节约型社会;可持续发展实质就是建设资源节约型社会;资源的稀缺性要求建设资源节约型社会.建设资源节约型社会是我国经济社会可持续发展的必由之路和唯一出路,势在必行.     

关于建设高素质农村基层干部队伍的思考

本文以广东省梅州市第四届村委会组成人员的文化程度和年龄结构为基本数据,对当前农村基层干部队伍现状、存在问题及原因进行分析,并提出建设高素质农村基层干部队伍的几点建议。     

林业资源型城市经济转型新思路

针对资源型城市伊春市的具体情况，从产业、运作方式、创新机制和观念，合理安排劳动力就业等方面，提出了实施资源型城市转型的新思路和新措施。     

再论发展精细化农业

本文给出了精细化农业的概念，并对其内容细分为19类，进而提出了发展精细化农业的建议。