Social resilience as a controlling influence on desertification in Senegal     

D. Bradley  A. Grainger 《Land Degradation \u0026amp; Development》2004,15(5):451-470

While ecological resilience may explain why apparent symptoms of desertification are often temporary, social resilience can prevent degradation resulting from overexploitation of land in response to drought and other constraints. This paper describes a Social Resilience Model in which actors switch from performance strategies to survival strategies when the perceived severity of constraints exceeds a critical performance–survival threshold (PST). This is determined in comparison with a reference mode that depends on a learning facility developed by repeated exposure to cycles of constraint, search and feedback. Actors select particular strategies by comparing welfare gains with their aspiration levels—a concept that allows more flexible decision making than profit maximizing or satisficing alone. The model is tested in the silvopastoral zone of Senegal, where desertification is not as widespread as commonly assumed, despite severe constraints. The two major ethnic groups, the Wolof (mainly croppers) and the Peul (mainly pastoralists) anticipate and respond to environmental and socio‐economic constraints differently, and have different performance and survival strategies. The Peul have the higher social resilience, with more flexible decision‐making objectives, greater mobility, a more extensive action space, a learning facility supporting efficient search and feedback processes, a reference mode attuned to high anticipation and recognition of stress, and a high PST. They also exhibit more continuous performance–survival switching than the Wolof, who make a radical change from cropping to labour migration and reliance on external support. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

桤木制浆造纸研究现状与我国桤木浆的开发利用   总被引：14，自引：2，他引：12       下载免费PDF全文

陈炳星  周志春  李光荣  黄光霖  杨林 《林业科学研究》1999,12(6):656-661

就桤木商用种植的生产潜力、制浆造纸和材性研究现状等进行综合评述。桤木是一种商用种植较有发展前景的阔叶树种,生长迅速、固氮能力强,木材性质类似于杨木和桦木,可用来开发研制不同的浆种,与针叶木浆或其它阔叶木浆配抄可以生产高质量的印刷纸和书写纸等。鉴于我国丰富的桤木遗传资源和现有的生产经营水平,大力发展桤木纸浆原料林,开发利用桤木木浆具有广阔的前景,对于缓解针叶木浆之不足,降低纸浆生产成本,使我国造纸业  相似文献   

一种用于农业产业化经营决策的估计方法——农副产品需求的收入弹性估计方法   总被引：2，自引：0，他引：2  

郑志安  傅泽田 《农业工程学报》1999,15(2):11-14

为了促进农业产业化经营决策的科学化,运用收入弹性理论,研究了我国农副产品需求的估计方法,探讨了农业产业化经营决策应遵循的思路。  相似文献   

用科学发展观统筹城乡发展     

王利民 《农机化研究》2005,(6):14-18

以江苏为例,阐述了城乡统筹发展是在加快城市化发展的基础上,强化城市主体辐射带动作用,促进城乡各种要素双向流动、优势互补,实现资源共享和合理配置,缩小城乡差别,实现城乡经济社会的和谐发展,使城乡共享现代文明的一种社会系统建设。城乡统筹发展不仅强调城乡经济一体化,同时要求城乡社会各项事业一体化,包括经济布局、科教文卫事业、户籍管理、劳动就业、社会保障、基础设施和生态环境建设一体化。为此,要用科学发展观统筹城乡发展,解决新时期农业、农村和农民问题,最终打破中国社会城乡分割的二元经济结构,进而实现全面小康的目标。  相似文献   

冷冻技术在昆虫标本制作中的应用研究     

刘玉卿  郜旭芳 《绿色科技》2014,(7):59-60

指出了昆虫标本制作是许多农林高校、职业技术学院病虫防治专业课以及中、小学生物课学习中必不可少的一项实践性教学环节。通过多年的实践和探索,总结出了一整套利用冷冻技术采集、制作和保存昆虫标本的新方法。新方法在诸多方面优于传统方法,安全、卫生、不脱色、不易被虫蛀、简单、方便、野外采集更加能体现其优势。此方法可应用于多种生物标本的制作中,为相关高校以及中、小学的昆虫标本采集制作开辟了一条新的途径。  相似文献   

Changing how we approach fisheries: A first attempt at an operational framework for ecosystem approaches to fisheries management     

Jason S. Link  Geir Huse  Sarah Gaichas  Anthony R. Marshak 《Fish and Fisheries》2020,21(2):393-434

The increasing need to account for the many factors that influence fish population dynamics, particularly those external to the population, has led to repeated calls for an ecosystem approach to fisheries management (EAFM). Yet systematically and clearly addressing these factors, and hence implementing EAFM, has suffered from a lack of clear operational guidance. Here, we propose 13 main factors (shift in location, migration route or timing, overfishing (three types), decrease in physiology, increase in predation, increase in competition, decrease in prey availability, increase in disease or parasites and a decline in habitat quality or habitat quantity) that can negatively influence fish populations via mechanisms readily observable in ~20 population features. Using these features as part of a diagnostic framework, we develop flow charts that link probable mechanism(s) underlying population change to the most judicious management actions. We then apply the framework for example case studies that have well‐known and documented population dynamics. To our knowledge, this is the first attempt to provide a clearly defined matrix of all the probable responses to the most common factors influencing fish populations, and to examine possible diagnostics simultaneously, comparatively and relatively in an attempt to elucidate the most probable mechanisms responsible. The framework we propose aims to operationalize EAFM, thereby not only better diagnosing factors influencing fish populations, but also suggesting the most appropriate management interventions, and ultimately leading to improved fisheries. We assert the framework proposed should result in both better use of limited analytical and observational resources and more tailored and effective management actions.  相似文献   

河南烟区烤烟经济性状的灰关联聚类分析评价   总被引：1，自引：0，他引：1  

张慢慢  邵惠芳  刘国庆  黄五星  赵蓉蓉  许自成 《中国农业科技导报》2016,18(2):121-127

为了比较河南省不同烟草种植区烤烟经济性状的差异,运用灰色关联聚类和决策分析方法分别对河南省10个烟草种植区的烤烟产量、上等烟和中等烟比例3个指标进行了综合评价。结果表明:根据不同烟区烤烟经济性状的差异,10个烟草种植区可分为4个类群:第Ⅰ类群主要包括三门峡、洛阳和济源烟区;第Ⅱ类群主要包括信阳烟区;第Ⅲ类群主要包括许昌、南阳、驻马店、平顶山和漯河烟区;第Ⅳ类主要包括商丘烟区。各类群烟区烤烟经济性状的综合表现为:许昌、南阳、驻马店、平顶山和漯河烟区表现最优,综合评价值为0.98;三门峡、洛阳和济源烟区次之,综合评价值为0.93;信阳烟区相对较低,综合评价值为0.89;商丘烟区综合评价值最低,为0.85。  相似文献   

矿用高压开关电器短路开断与关合试验电源     

陈钊 《保鲜与加工》2016,(2):58-63,106

针对国内冲击发电机性能参数不足,以国外冲击发电机作为试验电源,建立基于直接试验法的矿用高压开关电器短路开断与关合试验系统,提出了一种新的技术解决方案。仿真试验结果表明,该方案满足综合性煤矿高压电气实验室建设项目技术指标和试验标准要求,为大容量开断与关合试验系统设计和建造提供一种技术思路。  相似文献   

基于大系统分解-动态规划聚合法的多块滩涂围垦进度决策优化     

赵国锋  宋希杰  成立 《灌溉排水学报》2016,(4)

为了解决多块滩涂围垦进度决策问题,采用大系统分解-动态规划聚合法对多块滩涂的土地利用进行优化和最优开发。将多块滩涂框围进度最优决策模型分解为若干个单块滩涂土地利用规划线性子模型,采用动态规划逐次逼近法对子系统进行优化,确定各块滩涂在不同投资现值下的多阶段一系列优化结果与收益及费用指标体系,再针对各块滩涂围垦决策子模型采用动态规划法进行动态规划聚合,对多块滩涂进行围垦进度决策。求解方法能够给出多块滩涂框围进度和相应土地利用最优布局和开发进度决策。  相似文献   

酿酒葡萄新品种‘北馨’     

范培格  王利军  吴本宏  段伟  杨美容  黎盛臣  梁振昌  辛海平  匡阳甫  郭鋆鋆  廖宣峰  李前隽  李绍华 《园艺学报》2015,42(2):395-396

‘北馨’系山葡萄与欧亚种品种杂交而来的酿酒葡萄新品种。果粒近圆或椭圆形,紫黑色,单粒质量3.62 g,单穗质量155.5 g,可溶性固形物含量22.4%,可滴定酸含量0.64%,出汁率67.9%。早果性及丰产性强。抗寒、抗病能力强。酿成的酒呈鲜亮的宝石红色,香气清新,具有玫瑰香香气,入口甜美,酒体平衡,口感协调。  相似文献