基于食品召回成本模型的可追溯体系对食品召回成本的影响   总被引：2，自引：2，他引：0  

徐芬  陈红华 《中国农业大学学报》2014,19(2):233-237

针对我国食品召回过程中召回成本较大对企业召回积极性带来不利影响等问题,构建食品召回成本模型,测算建立可追溯体系和不可追溯体系下的食品召回量和召回成本,对比分析可追溯体系对食品召回成本的影响,并探究影响食品召回成本的主要因素。结果表明:在不可追溯体系下的食品召回成本是可追溯体系下召回成本的(m-1)倍(m为食品保质期),可追溯体系可极大减少召回成本;食品保质期、日产量、销售价格是影响食品召回成本的主要因素。  相似文献   

机电设备安装工程造价的有效控制与管理措施分析探讨     

张涛  李修建 《湖南农机》2014,(8)

文章通过对建筑工程造价的分析,介绍了机电工程安装的特点,并分析了影响机电设备安装工程造价的因素,总结出相对的控制方法和管理措施。  相似文献   

推进福建农业转移人口市民化的经济学分析     

陈孝文 《安徽农业大学学报》2014,(6):57-61

有序推进农业转移人口市民化是经济与社会发展的必然要求。在加快转变发展方式、积极稳妥推进城镇化和统筹城乡发展的影响下,福建省持续推进农业转移人口市民化。从农业转移人口个人来看,农业转移人口市民化的决策可以视为一种投资行为,其考虑迁移城市至市民化与否的经济动因是进行成本收益因素分析,包括直接成本、机会成本、心理成本及收入收益、教育收益、医疗收益、文化收益。作为公共政府应该制定措施,降低市民化总成本,积极推进农业转移人口市民化进程,要以强制性制度创新,构建促进农业转移人口市民化的政策体系。  相似文献   

The behavioural dynamics of fishers: management implications   总被引：4，自引：0，他引：4  

Silvia Salas  & Daniel Gaertner 《Fish and Fisheries》2004,5(2):153-167

In pursuing their livelihood, fishers develop strategies when faced with changes in regulations and other fishery conditions. Changes involve each individual in a decision‐making process governed by his/her own goals or constraints. Despite this reality, the complex dynamics of fishing has usually been ignored in designing management initiatives, which has contributed to management failures in many parts of the world. Fishers have generally been treated as fixed elements, with no consideration of individual attitudes based on their operating scales (geographical, ecological, social and economic) and personal goals. We review existing research on the social, economic and behavioural dynamics of fishing to provide insight into fisher behaviour and its implications for fisheries management. Emphasis is placed on fisher perception, and how fishers develop dynamic fishing tactics and strategies as an adaptive response to changes in resource abundance, environmental conditions and market or regulatory constraints. We conclude that knowledge of these dynamics is essential for effective management, and we discuss how such information can be collected, analysed and integrated into fisheries assessment and management. Particular emphasis is placed on small‐scale fisheries, but some examples from industrial fleets are provided to highlight similar issues in different types of fisheries.  相似文献   

Longer migration not necessarily the costliest strategy for migrating humpback whales     

Leena Riekkola  Virginia Andrews‐Goff  Ari Friedlaender  Alexandre N. Zerbini  Rochelle Constantine 《水产资源保护:海洋与淡水生态系统》2020,30(5):937-948

1. Long‐distance migration is a demanding physical activity, and how well animals manage the associated costs will have important implications for their fitness.
2. The Oceania humpback whale (Megaptera novaeangliae) population is recovering from past exploitation markedly slower than the neighbouring east Australian whales. The reasons for this are unknown, although higher energetic costs of longer migratory distances could be a possible explanation. Due to their fully aquatic lives, studying the energy expenditure of these large animals requires methods that do not rely on capturing the animal, such as bioenergetic models.
3. A state‐space model was fitted to satellite data to infer behavioural states for southern migrating whales. Travel speeds and behavioural states were used in a bioenergetic model to estimate the energetic cost of the migration phase. Relative differences in average duration, distance, and energetic costs were compared between migratory routes and distances.
4. Total energy used during migration was a trade‐off between cost of transport (determined by travel speed) and daily maintenance (determined by daily basal metabolic costs). Oceania whales migrating to the Amundsen and Bellingshausen Seas travelled fastest and furthest, 15 and 21% further than whales migrating to the d'Urville Sea (east Australian whales) and Ross Sea, respectively. Therefore, they had the highest cost of transport, 25 and 85% higher than for d'Urville Sea and Ross Sea whales, respectively. However, energy saved in terms of daily maintenance by using fewer days to complete a longer migration resulted in only a 6–7% increase in total energetic cost.
5. The results highlight that travelling further does not necessarily translate into an increase in total energy expenditure for migratory whales, since they can compensate for longer distance by travelling faster. Further research on the energetics of different whale populations could provide insight into the productivity of Southern Ocean feeding regions and help understand the environmental and anthropogenic effects on the whales' energy budgets.

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集水灌溉和施肥对半干旱区春小麦生态位适宜度和产量的影响     

李文龙  苏敏  李自珍 《农业工程学报》2010,26(4):42-48

为了探讨利用农业集水进行的控制灌溉和施肥对提高春小麦生态位适宜度和增加产量的重要作用,该文采用田间小区试验和建模分析方法,研究了不同供水和不同施肥对春小麦叶面积指数（LAI）、根生物量、生态位适宜度与产量的影响。结果表明：不同灌溉供水量与不同施肥量对春小麦LAI和根生物量都呈现出显著的影响,其中丰水、平水和自然降水比低水处理的LAI最大值（开花期）分别增加56.9%、30.9%和19.1%;根生物量平均值分别增加84.2%、50.4%和26.6%;同时施肥与相应不施肥相比亦有显著增加。春小麦生态位适宜度与产量的结果显示：在丰水、平水、自然降水和低水处理下的适宜度（F(t)）平均值分别为0.6631、0.5670、0.5174和0.4763,籽粒产量平均值分别为3 159.2、2 345.2、1 735.7和1 380.6 kg/hm2;其中丰水、平水和自然降水比低水处理的适宜度值分别提高了39.2%、19.0%和8.6%;平均籽粒产量分别提高了128.8%、69.9%和25.7%,这表明增加供水量具有提高适宜度和增产的显著正面影响。同时,施肥比相应不施肥也有提高适宜度和增产的积极作用。统计分析表明：适宜度与籽粒产量之间呈正线性相关关系。对试验中16种不同水肥组合处理的评价结论为：丰水下施低、中、高肥,平水高肥和自然降水高肥等5种处理下属适宜;其余11种处理下属中等或不适宜。各处理下的最大适宜度值（0.8351）和最高产量（4 275.8 kg/hm2）是在丰水高肥下一致达到,这表明丰水高肥是半干旱区的一种生态适应性和产量最佳的组合处理。  相似文献   

安徽省欠发达地区农村体育组织管理现状及对策   总被引：1，自引：1，他引：0  

邹钧人  汪映川  郑国祥 《安徽农业科学》2010,38(36)

对安徽省欠发达地区乡镇、行政村全民健身领导机构的设置,组织开展农民体育竞赛与体育健身活动,提供农民体育技术指导、咨询及体质测试,提供农民体育文化信息和宣传普及体育科普知识,开展送体育下乡活动等组织管理状况进行调查研究,并提出相应的对策。  相似文献   

浅议园林景观工程造价控制     

刘红娟  徐秋林 《黑龙江农业科学》2013,(11):115-117

针对园林景观工程造价难以控制的现状以及园林景观工程造价控制存在的问题，分析了影响园林景观工程造价的因素，分别对决策阶段、设计阶段、招标阶段、施工阶段以及竣工养护阶段提出了园林景现工程全过程造价控制的相应对策。  相似文献   

新疆棉花优质高产节本增效栽培的途径   总被引：1，自引：0，他引：1  

张权中 《新疆农业大学学报》1999,22(1):34-36

本研究依据新疆棉花生产面临的问题，提出了在保证优质高产前提下，从减少物质、机械、人工等方面的投入入手，简化栽培、节约成本、增加效益。  相似文献   

螺旋插补铣在加工多孔盘类零件中的应用     

郭红娟  王拥军  余巧红 《拖拉机》2013,(5):68-69,74

传统的盘类加工工艺方法在加工此类Q345材质零件时，刀具成本较高，生产效率低。通过生产实例的加工工艺，证明了螺旋插补铣在孔加工中的低刀具成本优势与高的生产效率。  相似文献