厌氧发酵液商品化开发研究   总被引：2，自引：0，他引：2  

姚燕  王艳锦  李改莲  张运真 《河南农业大学学报》2003,37(1):78-80

通过对厌氧发酵技术在中国难以推广的问题分析，论述了厌氧发酵液商品开发的前景，认为其具有商业开发价值。  相似文献   

流域水资源可持续开发利用中激励机制的应用   总被引：3，自引：0，他引：3  

刘宪春  张强莉 《农业现代化研究》2003,24(5):339-343

流域水资源是人类文明发展的重要源泉。随着流域人口和经济的快速发展，流域水资源不足和水环境恶化已成为制约流域经济发展的重要因素。造成这种状况的主要根源是流域水资源的公共性、外部性、价格偏离价值及政府失灵等。为了实现流域水资源的持续开发利用，必须改变现有流域水资源开发利用模式。本文根据可持续发展理论和环境经济原理，指出流域水资源开发利用中应引入激励机制。激励机制的应用应遵循以下原则：①公平性原则；②效益原则；③补偿性原则；④可操作性原则；⑤生态环境保护原则。具体的激励机制包括：①价格机制；②宏观调控机制；③水权机制；④相应的流域管理机制。  相似文献   

江西绿色食品开发初探     

霍光华  高荫榆  汪怀建 《江西农业大学学报》2002,24(3):419-422

阐述了绿色食品及其与有机食品和生态食品的关系 ,发展绿色食品具有显著的生态、社会和经济意义。江西生态环境优越 ,特色种类资源丰富 ,开发绿色食品 ,适合江西省情。依照有关法规 ,通过土壤、大气、水和市场等调查 ,确立生产基地、生产对象和加工方式。引入高新技术 ,保证绿色食品的安全、营养、天然性 ,形成绿色产业 ,振兴江西经济  相似文献   

论西部大开发中黄土高原的国土整治问题     

张志力 《山西农业科学》2001,29(3):90-93

分析了黄土高原在西部大开发中的重要战略意义以及由此产生的新的环境生态问题 ,在对国土整治方略和生态重建的理论与观点进行研究的基础上 ,提出了新形势下黄土高原开发整治的策略和建议  相似文献   

生产要素对我国海洋渔业经济可持续发展的影响     

高健  陈大群 《上海海洋大学学报》2003,(Z1)

根据资源的稀缺性理论,讨论了我国渔业生产要素对海洋渔业可持续发展的影响和生产要素的经济效率。研究表明,我国近海渔场和海洋渔业资源的减少,正成为制约我国海洋渔业可持续发展的主要因素。而近沿海海域对我国海洋养殖产业的经济增长将扮演越来越大的作用。在海洋渔业发展初期,渔业劳动力投入量对推动经济增长有较大的作用,但是,在现阶段,海洋渔业劳动力要素的投入量对海洋渔业经济的增长作用越来越低。目前,海洋渔业劳动力要素投入过剩现象已经十分严重,通过增加海洋渔业劳动力生产要素投入提高海洋渔业经济增长的作用受到制约。对资本要素的研究表明,我国渔民的平均剩余资本低,渔民再投资能力弱,造成渔业人口剩余资本低下的主要原因与我国政府农业政策和渔民的消费习惯有一定的关系。渔业技术进步能提高生产效率。然而,研究表明,大量的研究成果还未能有效地转化到生产中去。我国海洋渔业生产仍然是劳动力和土地密集型,技术革新和组织制度资源相当短缺。尤其是组织和制度资源的短缺,将成为制约我国海洋渔业经济可持续发展的最大问题。我国海洋渔业生产的组织资源表现出明显的极性结构。一端是仍然带有计划经济色彩的集权渔业管理机构,一端是已经完全市场化的高度分散的生产个体。在...  相似文献   

沙棘SSR分子标记的开发     

孙燕琳  阮成江  金华 《安徽农业科学》2007,35(1):45-46,93

利用已报道的葡萄SSR引物筛选适用于沙棘的SSR引物.结果表明,在供筛选的107对引物中,只有1对引物在沙棘中无扩增位点,有效扩增比率为99.07%;共有46对引物的在2个沙棘品种间扩增出多态性位点,有效扩增比率为42.99%,扩增产物共表现出100个等位基因,其中差异等位基因数为70个,每对引物的等位基因数为1～4个,平均为2.174个.根据这46对引物的扩增结果,中国沙棘和辽阜1号间的遗传相似系数为0.413,遗传距离为0.587.  相似文献   

粗糙集聚类分析对姜黄属植物数值分类的研究          下载免费PDF全文

王正德  秦毓茜  杜敏华 《西北农林科技大学学报(自然科学版)》2007,35(11):203-212

为了为姜黄属植物分类与中药鉴定提供新的参考,以姜黄属(Curcuma L.)的31个材料为研究对象,把47项分类性状(指标)分解为28个定性指标和19个定量指标,将28个定性指标进一步分解为二元性状指标和三元性状指标,然后各自进行粗糙集理论的处理和聚类,把聚类结果按交集分类的办法形成定性指标综合分类的结果;将19个定量指标进行粗糙集理论的处理和聚类,把聚类结果与定性指标的分类结果按交集分类的办法形成20项指标综合分类的结果。结果表明,将定性性状指标分类集与定量性状指标分类集进行交集分类,姜黄属植物的31个材料可分为10个类群(种);这与前人采用47项指标一次性完全聚类的结果存在差异,与传统分类也不完全相同。说明粗糙集理论对于分类指标的处理,一方面去掉了对分类没有显著作用的指标,减少了运算;另一方面减少了不必要指标对分类的影响,使分类更为准确。  相似文献   

Potential impacts of emerging mahi-mahi fisheries on sea turtle and elasmobranch bycatch species     

Sophie Whoriskey  Randall Arauz  Julia K. Baum 《Biological conservation》2011,(6):1841-1849

Mahi-mahi (Coryphaena hippurus) is a resilient pelagic species that could provide long-term highly productive fisheries. Using FAO data we document enormous increases (746%) in reported global mahi-mahi landings since 1950. Detailed mahi-mahi fisheries records are limited, but an observer program monitoring Costa Rica’s Pacific mahi-mahi pelagic longline fleet between 1999 and 2008 (n = 217 sets) provided a rare opportunity to quantify bycatch in these fisheries. Several sea turtles and sharks of global conservation concern were caught incidentally: olive ridley turtle (Lepidochelys olivacea; n = 1348, mean = 9.05 per 1000 hooks), silky shark (Carcharhinus falciformis; n = 402, mean = 2.96 per 1000 hooks), thresher sharks (Alopias sp.; n = 158, mean = 1.12 per 1000 hooks), green turtle (Chelonia mydas; n = 49, mean = 0.35 per 1000 hooks), and three other threatened sharks in small numbers. Pelagic stingray (Pteroplatytrygon violacea; a ray of low conservation concern) was also a common bycatch (n = 625, mean = 4.77 per 1000 hooks). Generalized linear models (GLMs) of catch rates showed increases in olive ridley turtles and decreases in mahi-mahi and silky sharks over the decade examined. The high hooking survival rates of olive ridley and green turtles in observed sets (95% and 96% respectively) suggest that widespread training of the fleet in careful gear removal and turtle release methods could be one effective bycatch mitigation strategy for these species. GLMs also provide evidence that closing the fishery during peak olive ridley nesting times (at least near nesting beaches), in combination with reduced gear soak times, could help minimize the fishery’s impacts on threatened bycatch species while still maintaining a productive fishery.  相似文献   

Assessing the impacts of international trade on CITES-listed species: Current practices and opportunities for scientific research     

Matthew J. Smith  Hesiquio Benítez-Díaz  Margarita África Clemente-Muñoz  John Donaldson  Jon M. Hutton  H. Noel McGough  Rodrigo A. Medellin  David H.W. Morgan  Colman O’Criodain  Thomasina E.E. Oldfield  Uwe Schippmann  Richard J. Williams 《Biological conservation》2011,(1):82-91

The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) came into effect in 1975 to protect certain species of wild fauna and flora against over-exploitation through international trade. Determining which trade is detrimental to the survival of species in the wild can be a major difficulty in the implementation of CITES by national authorities, partly due to limited knowledge and understanding of the species’ biology, management, and the impacts of harvesting. Some of this knowledge could be acquired through targeted scientific research. However, to date there exists no general overview of the current use of biological information in determining detriment in CITES to help scientists identify research priorities. For an international meeting in 2008, over 100 scientists and regulators compiled 60 case studies covering a wide range of CITES-listed taxa, outlining how information on the biology, harvesting and management might be used to determine whether international trade is detrimental. We used these case studies, workshop conclusions, and other published literature, to identify 10 potential research directions for the scientific community which, if addressed, could greatly assist in the making of Non-Detriment Findings. We hope that this will encourage more scientists to study CITES-listed species, and foster more collaboration between research scientists, CITES national authorities, CITES technical committees and local communities. The case studies highlight a general need for advice on how to identify and manage levels of risk involved when assessing possible detriment, and for advice on assessing detriment under complex harvesting scenarios such as when multiple species, or parts of individuals, are harvested. Broadly, they highlight an opportunity for scientists to further develop a body of scientific studies that propose, refine and adapt methods for assessing detrimental trade in CITES-listed taxa. Comparisons within life-form groups indicated the potential for the identification of practical advice that could apply to groups of taxa. The case studies highlighted a widespread need for more information gathering studies of CITES-listed taxa such as the broader impacts of harvesting on populations and ecosystems, and the potential long-term evolutionary impacts. The case studies also highlighted the need for practical advice on how to implement adaptive management programmes and for research into enterprises based on the harvesting of CITES-listed species from the wild.  相似文献   

Impacts of fishing by dewatering on fish assemblages of tropical floodplain wetlands: A matter of frequency and context     

Sarah M. Martin  Kai Lorenzen  Robert I. Arthur  Phaisane Kaisone  Kanthavong Souvannalangsy 《Biological conservation》2011,(1):633-640

Tropical floodplain wetlands and the fish communities they support are subject to great pressure from human demands for water and aquatic living resources. In densely populated agricultural areas where such pressures are greatest, floodplain wetlands may be dewatered for the dual purpose of crop irrigation and fish harvesting. Viewed as highly destructive to fish communities, the practice is widely discouraged but remains common. We investigated the impacts of dewatering on fish abundance and assemblage structure in permanent floodplain wetlands of the lower Mekong region. Draining was carried out only in wetlands where access for fishing and water withdrawal was exclusive to individual households or groups, and where fishing was restricted to draining events. Subsequently, the impacts of draining were found to be equivalent to those of intensive fishing, rather than entirely catastrophic. Many wetlands were drained and fished repeatedly in a single dry season, with catches declining by 72% on average between consecutive events. Species richness and mean length of fish also declined with consecutive dewatering events. Fish biomass was higher in drained wetlands prior to the first and second draining events than in open access, non-drained wetlands. These surprising results suggest that draining of floodplain wetlands is not as fundamentally destructive to fish populations as is often assumed. Where fishing pressure under open access conditions is high, allocation of exclusive rights to fish and dewater wetlands can aid fish conservation as long as dewatering is carried out only once.  相似文献