Production economics of the emerging private fish farming industry in Bulgaria

The production economics of the emerging Bulgarian private carp and trout farming industry were assessed by surveying a representative sample of 20 private and state-controlled farms as well as visiting the National Fresh Water Fish Research Institute, the state-owned fish feed production plant and a fish processing plant.The major constraints for the development of profitable fish farming were found to be the lack of capital and the insecurity of tenure, which nonetheless, do not serve to discourage new entrants into the industry. The expected gross margin per tonne of carp produced in reservoirs or earth ponds is USD 487, while a tonne of trout farmed in concrete raceways shows a gross margin figure of USD 525. State-owned trout farms are only available for outright purchase at auctions, whereas carp farms may be rented, but only for a short term.Fish farmers could benefit from organizing themselves into producer groups in order to improve marketing and secure quality inputs. In particular, there is scope to source quality dry fish diets on both economic and environmental grounds.An extension advisory service is needed to support inexperienced new entrants and researchers should urgently evaluate what seem to be the most cost-effective methods of production.     

The Economics of Kappaphycus Seaweed Cultivation in Developing Countries: A Comparative Analysis of Farming Systems

The farming of the red seaweed Kappaphycus alvarezii and related species as raw material for the hydrocolloid carrageenan rapidly spread from the Philippines in the late 1960s to Indonesia, Tanzania, and other tropical countries around the world. Although numerous studies have documented positive socioeconomic impacts for seaweed farming, factors such as diseases and distance to export markets have led to an uneven development of the industry. Using standard budgeting techniques, this study adapted production and market data from a FAO-led global review of seaweed farming to develop comparative enterprise budgets for eight farming systems in six countries (Indonesia, the Philippines, Tanzania, India, Solomon Islands, and Mexico). Although the basic technology package is the same across countries, the study revealed large differences in the economic performance of systems due to wide variations in farm prices and the scale of operations. Although seaweed farming is a suitable activity for small-scale producers, a minimum of 2,000 m of cultures lines are still necessary to ensure adequate economic returns. Greater farming plots may be needed if farm prices are well below the average farm prices paid in Indonesia and the Philippines. Policy recommendations are made to improve the economic potential of underperforming systems.     

翅果油树研究进展

对翅果油树的植物学、细胞学、分类学、生理生化、生态学和群落学、经济生物学等方面的研究进行了较全面的总结,并提出了今后的研究方向,旨在促进翅果油树的研究和开发.     

城市森林净化能力计量研究及经济补偿政策的探讨

本文分析目前森林净化能力的计量研究方法和存在的问题,提出通过建立城市森林净化能力计量模型,实行差别化生态效益经济补偿政策的观点和相应补偿办法。     

基于面板数据模型的中国农业生产用能与农业经济增长关系

为揭示不同区域农业生产用能与农业经济增长的差异,该文以中国东中西地区为研究对象,利用1990～2008年农业生产用能与农业产值数据构筑面板数据模型进行分析。结果表明,各地区农业生产用能与农业产出增长均存在格兰杰因果关系,随着地区发达程度的降低,这种关系越发明显;同时,西部地区农业生产用能与农业产出增长还存在双向长期格兰杰因果关系。通过模型分析,进一步定量揭示了各地区间农业生产用能与农业产出增长之间关系的差异,以及地区内部各省份之间也存在差异;详述了区域经济发展水平与农业经济增长关系的密切程度,以及继续增加农业投入与农业经济持续增长出现差异的原因。最后指出,在农业现代化普及地区,重点是提高农业物资利用效率和使用合理的种植结构,而在农业现代化中等及欠发达地区,应注重农业物资投入及效率提高。     

好氧预处理对干法沼气发酵产气量的影响及能量损失

研究好氧发酵预处理对干法沼气发酵产气效果的影响及能量损失情况,是以好氧发酵升温为预处理方式的干法沼气工程经济运行的重要依据.该文采用恒温沼气发酵装置,以牛粪及少量混合秸秆粉作为发酵原料,研究了不同好氧发酵预处理条件下,干法沼气发酵的产气效果并对其能量损失情况进行了分析探讨.结果表明:以牛粪为主要发酵原料时,好氧预处理对物料干法沼气发酵的产气量有较明显影响,随着好氧发酵时间增加和温度提高,总产气量减少,能量损失增大;好氧发酵预处理温度与沼气发酵温度相同(均为35℃)时,能量损失较少,好氧发酵升温法合理;好氧发酵预处理温度(55℃)显著高于沼气发酵温度,好氧发酵升温法会带来较大能量损失.因此,在对覆膜槽生物反应器操作时,应准确把握好氧发酵的时间和温度,一旦达剑所需温度,应立即转入沼气发酵,以提高沼气产量,减少能量损失.     

编辑·科技期刊·市场经济——以中国水利行业科技期刊的发展为例

介绍了市场经济背景下中国科技期刊面临的问题,以中国水利行业科技期刊的发展为例,提出了科技期刊如何走出困境的对策：适应市场经济要求,树立效益和市场理念,开展行业期刊调查;期刊读者调查;专家队伍调查;广告对象调查;与高校协办;发动编委会;组建理事会;强化内部管理。     

基于主成分聚类分析的安徽省区域经济综合评价

根据2007年最新统计资料,采用新型的主成分聚类分析方法对安徽省区域经济的发展现状进行分析与评价。结果表明:安徽省17个省辖市可以划分为5类,其中合肥作为省会,是全省综合实力最大、竞争力最强的城市。评价结果符合安徽省经济发展实际。     

汶川地震次生山地灾害危险性评价及震后减灾对策经济学分析

从地形地貌、地质、气候、水文、植被、灾害状况、人类活动等7个方面选取11个因子,采用定性与定量相结合的方法,引入危险性指数来评价汶川地震次生山地灾害的危险性大小,并利用GIS技术,按区域因素"相同或相似归类、相异分级"的原则,将研究区分为高度危险区、中度危险区、低度危险区和无危险区等四个等级,进行次生山地灾害危险性评价与区划,并运用最优灾害成本模型对减灾投入进行经济性评价,从而提出合理的防灾减灾对策与建议。     

《马克思主义经济学》教学现状调查与思考

为了全面了解《马克思主义经济学》课程教学的实际情况,采用问卷调查法,针对学生对该课程的总体评价、学生的学习态度、对所学知识的应用能力、对教学进度与方法的期望几个方面进行了调查研究;在此基础上,提出了实施因材施教、案例教学、分组讨论、改革考核方式等具体措施。