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作为区域经济的主导力量,产业集聚的重要性不言而喻。利用产业集聚理论剖析中国重庆畜牧科技城畜牧业相关产业集聚的生成机制,研究认为其兼具原生型、嵌入型与衍生型产业集聚的特点,是企业追求自利的自下而上的自组织与政府政策引导自上而下的有组织的结合,并对畜牧养殖业、饲料、兽药、畜产品加工等产业集聚效应及不足进行了分析。 相似文献
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中国肉禽产业集聚现状与其主要影响因素分析 总被引：2，自引：2，他引：0
在产业发展过程中,同一产业在某个特定区域内高度集中的现象经常出现,这种产业集聚对于农户、企业的利益甚至整个产业的发展影响重大,因此对产业集聚进行研究也具有比较重要的意义。本文即以中国近30年来发展迅速的肉禽产业为研究对象,针对产业集聚的特征,分肉禽养殖和禽肉加工两个方面着重分析了中国肉禽产业的集聚现状,并对形成这种现状的主要影响因素进行了分析。 相似文献
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中国的肉牛养殖是一个动态的变化过程，为了找出肉牛养殖集聚变化的影响因素，本文采用重心模型分析中国肉牛养殖区域的变动，构建了动态固定效应空间杜宾模型，检验了资源禀赋、比较收益和政策效应对中国肉牛养殖区域变动的影响，估算了这些因素的空间溢出效应并将其分解为短期影响和长期影响。研究结果表明，中国肉牛养殖中心变动呈现出“先东北后西北、西南”的趋势，养殖行为存在空间聚集现象。对其成因的研究发现：从短期和长期影响来看，草地优势、产业优势和牛肉价格都具有正向的影响。肉牛养殖区域的变化是养殖户的理性选择行为体现，建议充分考虑省份间的空间溢出效应，重视省份间肉牛养殖的空间相关性，因地制宜制定产业扶持政策，助推肉牛产业发展。 相似文献
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推进水禽产业集聚的路径研究 总被引：2，自引：0，他引：2
20世纪90年代以来,产业集聚成为推动中国区域经济发展的重要形式。本文从分析我国水禽产业集聚的现状入手,提出完善和延伸产业链,整合要素资源,政府主导、市场运作,强化专业分工与协作,加快产业转型升级,促进和催化我国水禽产业集聚的对策与路径。 相似文献
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在产业集聚理论框架下,以产业集中度和区位商系数测算为分析工具,利用《中国畜牧兽医年鉴》2010-2018年全国及各省(市)自治区牛肉产量等数据,考察分析了中国肉牛主产区产业集聚现状及影响中国肉牛产业集聚发展的各种因素。研究发现,中国肉牛产业集聚程度高,具有比较优势,而资源禀赋条件、政府优惠政策的实施、标准化养殖技术的推广、区域品牌的形成是中国肉牛产业集聚程度的主要影响因素。 相似文献
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<正>一、饲料产业发展现状及研究意义根据国家统计局资料显示,2018—2020年,我国大牲畜总量分别为9625.5万头、9877.42万头、10265.06万头;2018—2021年,我国饲料总产量分别为24213.3万吨、26184万吨、29355万吨、31696.5万吨,由此可见,饲料行业需求呈现出逐年增长的趋势。产业集聚的相关研究表明,产业集聚能够促进资源、信息、技术、劳动力、资金等要素在空间上产生集聚效应,通过各类生产要素流通增强企业间的分工与协作,实现区域产业经济一体化发展,从而发挥规模经济效益促进区域经济增长。 相似文献
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为了探究畜牧业产业集聚对畜牧业碳排放的影响，研究基于2001—2020年我国31个省(自治区、直辖市)的畜牧业面板数据，在对畜牧业产业集聚、畜牧业碳排放总量和强度进行测算的基础上，使用Moran’s I指数探究其空间自相关性，通过构建库兹涅兹曲线模型与空间杜宾模型(SDM)探究畜牧业产业集聚对畜牧业碳排放的作用机制。结果表明：各地区畜牧业碳排放总量与强度近年来均有所降低，但西部地区仍然远高于其他地区。畜牧业产业越来越集中于中西部地区，东部地区的畜牧业产业集聚程度有下降的趋势。畜牧业碳排放强度与产业集聚度均存在显著集聚的空间自相关性，前者以低低聚集为主，后者以高高聚集和低低聚集为主。畜牧业产业集聚与畜牧业碳排放之间存在倒“U”型关系，在产生抑制作用前会促进畜牧业碳排放。畜牧业产业集聚对畜牧业碳排放强度有正向空间间接效应，能够提高邻近地区的畜牧业碳排放强度。畜牧业产业集聚的短期直接效应、间接效应和总效应均小于长期效应。因此，应当制定合理的碳排放目标，尽快提高畜牧业产业集聚水平，发挥集聚效应与示范效应，达成农业领域的碳减排目标。 相似文献
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《黑龙江畜牧兽医》2020,(16)
为探究环境规制对生猪养殖产业集聚的影响,笔者首先从理论上梳理了环境规制影响生猪养殖产业集聚的可能路径,然后利用2004—2017年生猪养殖的省级宏观数据,通过计量方法实证检验了环境规制对生猪养殖产业集聚的影响。结果表明:环境规制强度与生猪养殖产业集聚之间存在"U形"关系,且这种影响关系存在明显的地区差异。在生猪养殖的重点发展区、约束发展区和潜力增长区,环境规制强度和生猪养殖产业集聚之间均存在"U形"关系;而在生猪养殖的适度发展区,环境规制强度对生猪养殖产业集聚的影响不明显。基于上述研究结论,笔者建议政府因地制宜地实施环境规制政策,推动各地区生猪养殖产业尽快突破"U形"曲线的拐点,实现环境改善和产业集聚的双赢。此外,政府还可以通过定期开展养殖技术培训、完善集聚区内交通设施、加大政策支持力度等措施来提升生猪养殖产业集聚度。 相似文献
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K. Suzuki M. Kanameda T. Ogawa T.T.D. Nguyen T.T.S. Dang Q.H. Luu D.U. Pfeiffer 《Livestock Science》2006,101(1-3):242-250
The objective of this field questionnaire survey was to describe the productivity and socio-economic profile of dairy cattle farmers in northern Vietnam considering regional differences in rural smallholder farming communities which have been targeted by a governmental dairy development policy. Using two-stage cluster sampling, a total of 99 dairy farming households (11 per commune) were recruited from 9 of 32 communes in Ba Vi District, Ha Tay Province, northern Vietnam. The results from this study indicate that there were regional differences in relation to basic management practices such as effective utilisation of agricultural by-products for feeding and hygiene practices. These can be explained by variation amongst the regions with respect to environmental factors affecting agricultural activities such as constraints on land use and access to water resources. There were also regional differences in the use of governmental support such as agricultural extension services and financial institutions. These can be attributed to proximity of the communities to each of the extension institutions as well as the phased and community-specific approach to the provision of governmental financial support for dairy development. 相似文献
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L. Lattuada F. Quaglia F. Iannelli C. Gissi P. Mantecca R. Bacchetta & M. Polli 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2009,126(2):154-163
In order to investigate the relationships between Italian wild boar and major pig breeds, we studied the genetic variability of four wild boar populations in Italy (Arezzo, Pisa, Parma, Bergamo) using a 533-bp fragment of the mitochondrial control region. Sixty-nine wild boar samples were analysed, allowing the identification of 10 distinct haplotypes, which involve a total of 15 single nucleotide polymorphisms. Phylogenetic and network analyses were performed also considering several sequences of wild and domesticated forms available in the databases. The Bayesian phylogenetic tree and the Median-Joining network analyses show three main groups: the Italian (IT), European (EU) and Asian (AS) clades. The IT clade corresponds to the Maremma endemic wild boar population and also includes Sardinian individuals, while the EU and AS groups include wild boars as well as domestic pig breeds. Only two individuals from Pisa cluster in the IT group, whereas two haplotypes from Bergamo cluster in the AS group and all other samples cluster in the EU clade. These findings suggest that in Italy wild boar populations have a mixed origin, both EU and AS, and that an interbreeding between wild and domesticated strains has probably occurred. Eight of the 10 wild boars coming from the Migliarino-San Rossore-Massaciuccoli Regional Park (Pisa) belong to H2 and H3 haplotypes, and cluster into the EU clade, suggesting that this regional park is not anymore exclusive of the endemic Maremma wild boar. 相似文献
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Marian E. Vernon Zachary Bischoff-Mattson Susan G. Clark 《Human Dimensions of Wildlife》2016,21(1):65-85
Incidents of human–wildlife conflict can solidify participant perspectives and expectations, and reveal underlying social and institutional dynamics. We describe and analyze two incidents of conflict between hunters and grizzly bears in 2011 and 2012. Both incidents were associated with the controversial elk hunt in Grand Teton National Park, Wyoming. We gathered quotes from opinion-editorials and interviews, categorized quotes according to type, and used cluster analysis to identify discourses and associated coalitions of participants. We examined how participants defined problems, used evidence, and advocated solutions in relation to these incidents. Participant discourses addressed technical and procedural issues of regional wildlife management that extended beyond these incidents, revealing divergent expectations about wildlife management on public lands. Existing decision-making processes dominated by government agencies do not appear to be addressing these expectations. We recommend an integrative, outside appraisal of regional elk management to address conflict and support ecologically sound decision-making that serves common interests. 相似文献
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山东省小麦田杂草组成及群落特征 总被引：12，自引：0，他引：12
采用倒置“W”型九点取样法对山东省小麦田杂草进行了调查,明确了山东省小麦田田间杂草的种类组成及群落结构。调查结果表明:山东省小麦田杂草共有 69种,隶属于21科,54属,其中禾本科、菊科和十字花科杂草种类最多,禾本科杂草为15种,菊科杂草11种,十字花科杂草8种,优势杂草有播娘蒿、荠菜、猪殃殃、雀麦、麦瓶草、小花糖芥、麦家公、看麦娘、节节麦和打碗花等10种,这10种杂草是构成山东省各地区小麦田杂草群落的优势种,此外区域性优势杂草有15种,一般性杂草有44种。从杂草区域分布来看:山东省7个区域中鲁西南平洼区的物种丰富度、物种多样性和均匀度指数均最高,其次是鲁南山区和鲁中山区,而鲁西北平原区和鲁北滨海区的辛普森指数最高。经聚类分析,山东省小麦田杂草群落分为4组:鲁西南平洼区和鲁南山区群落结构类似为一组,此组杂草种类和数量均多,发生重;胶东丘陵区、胶潍河谷平原区和鲁中山区群落结构类似为一组,此组杂草种类和数量介于中等,发生较重;鲁西北平原区和鲁北滨海区与其他地区差异较大,单独划为两组,这两组杂草发生种类和数量均少,跟其他组差异均较大。 相似文献
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冰草属植物种质资源遗传多样性的ISSR分析 总被引：3，自引：0，他引：3
用ISSR标记对来自国内外的33份冰草材料的遗传多样性进行了检测。从93条ISSR引物中共筛出11条能扩增出清晰条带并具有多态性的引物,33个样品DNA共获得84个扩增位点,其中多态性位点59个,平均每个引物扩增位点为7.64个。品种间遗传相似系数在0.083～0.706,表现出丰富的遗传多样性。利用UPGMA聚类分析,以遗传相似系数0.52为界限,33份材料划分为4类,聚类基本符合地理来源相近的材料聚为一类,呈现出一定的地域性分布规律。 相似文献
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Exploratory spatial relative risk mapping 总被引：2，自引：0，他引：2
Berke O 《Preventive veterinary medicine》2005,71(3-4):173-182
The many faces of disease mapping include maps of disease case locations, regional counts of cases, and disease risk. Another approach is that of mapping the relative risk. Previous methods to map the relative risk were based on regression models of relative risk, given information about geographical locations and established risk factors. However, spatial epidemiological investigations are often exploratory with limited knowledge about the putative risk factors. Indeed, often the primary motivation for the analysis is to identify unknown geographically varying risk factors.
An exploratory approach to mapping the spatial relative risk is to scale the risk map using the background risk in the unexposed (or less-exposed) population. Exposure to unknown spatial risk factors is defined via specific cluster analysis. Identification of spatial disease clusters separates the population into those inside and those outside high risk areas (the exposed and unexposed populations). This exploratory approach to relative risk mapping gives the investigator an impression about the importance and geographical distribution of the unknown spatial risk factors.
Two examples illustrate the exploratory relative risk mapping approach using a spatial point data set on pseudorabies in pig-herds and a regional count data set on small fox tapeworm infections in red foxes. 相似文献
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This paper presents a stochastic simulation model to evaluate the efficacy of regional or national surveys aimed at identifying infection in populations of animals. The process of evaluation involves specification or calculation of cluster-level test sensitivity and specificity, which are derived from two probability distributions of the number of individual-level positive tests expected from non-infected and infected clusters, respectively. Probability distributions for the number of positive clusters expected in a situation of freedom from infection and under various levels of cluster prevalence are specified and used to determine survey properties (the survey being considered a diagnostic system), and ROC curves are drawn. Likelihood ratios allow investigators to state the extent to which a survey result is more likely to be observed if the region or country is infected at a given prevalence than if it is free from infection. The result of a survey carried out to investigate the presence of porcine reproductive and respiratory syndrome (PRRS) in Switzerland is used to illustrate this approach. The model can be adapted to a wide range of survey designs. 相似文献
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用ISSR标记技术对来自国内外的73份豌豆材料进行遗传多样性分析,结果表明,100个ISSR引物中共筛选出11个多态性明显、条带清晰、反应稳定的引物,73份材料DNA共扩增出91条条带,其中78条为多态性条带,平均每个引物扩增的条带数为8.2条,多态性比率为86.4%。Shannon多样性指数平均为0.420 2,每个位点的有效等位基因数为1.451 8,品种间遗传相似系数变幅为0.406 5～0.934 0,表现出丰富的遗传多样性。利用UPGMA聚类分析,以遗传相似系数0.52为界限,73份材料划分为5类,聚类基本符合地理来源相近的材料聚为一类,呈现出一定的地域性分布规律。 相似文献