人口与市场因素对海洋渔业消费品影响的仿真分析 --以舟山市为例

本文以舟山为例,构建了人口变化、海洋消费需求与海洋生产的系统模拟框架,并利用系统动力学的方法,选择海水养殖、价格指数以及旅游人口三个对人口、海洋消费与生产系统产生重要影响的因素进行了仿真政策分析.结果表明,对海水养殖生产投入的增加不但可以满足人们持续增长的海洋水产品的需求,而且可以保证海洋渔业资源的可持续发展;此外,海产品价格指数的高低以及旅游人口的增加同样影响着海洋渔业消费品市场.     

人口增长和消费模式对海洋渔业资源影响的实证分析——以舟山为例

现有研究文献显示,人口增长和消费变化是影响海洋渔业资源变化的重要动因。以舟山为例,在建立构建人口、消费与海洋渔业资源相关关系的理论框架基础上,动态地分析舟山人口增长和消费模式转换是如何影响其海洋渔业资源的。实证研究表明:①由收入水平提高所引起的消费方式转换比人口规模更直接地影响海洋渔业资源的动态变化;②尽管捕捞量持续增加,但由于捕捞强度的迅速提高,单位捕捞努力渔获量在显著下降,预示着舟山渔场渔业资源的逐渐衰减;③影响海洋渔业资源变化的动因不仅包括人口增长和消费模式变化,同时还要考虑经济增长模式、市场价格、政策引导以及当地居民行为等因素。     

“新东部”渔业资源人口承载力实证分析——以山东省为例

本文以“新东部”海洋渔业强省——山东为例,参照全国,对比了该区域相对渔业资源人口与经济承载力的理论值与实际值。文章倚重合理的权重选择,研究了从1978到2004年其人口与渔业资源的匹配关系。研究表明。山东渔业资源人口承载力经历了从超载、极大富余到富余三种状态,但未来发展存在不确定性。这些不确定性表明“新东部”海洋资源人口承戢力的存在、持续发展与海洋生物技术水平发展、人类生活方式选择、海洋环境生态等多种因素密切关联。海洋渔业资源来源的不确定性以及人类海洋技术掌握的局限性将决定其人口承载力的极值。目前只有抛弃粗暴利用海洋渔业资源的方式。才能长久维持人与海洋渔业资源的和谐与互惠。     

人口、消费、技术模式变化对我国海洋渔业生产影响的实证研究——以浙江舟山渔场为例

本文以舟山为例 ,在以往研究的基础上 ,修正了过去所建构的人口、消费、生产和资源的系统模拟分析框架 ,并利用系统动力学的方法 ,选择了投资规模、技术进步等变量进行了系统仿真模拟分析。研究结果表明 ,在渔业资源限定条件下 ,投资规模对渔业生产的影响是有限的 ;而技术进步的影响则是十分显著的 ;同时 ,劳动力资源短缺也将会显现出来     

区域人口承载能力的多因素分析——以上海为例

上海人口增长的规划控制目标,从根本上取决于其人口承载量的拓展潜力.区域人口承载能力研究,所面对的是由人口、资源、环境、经济和社会构成的复杂巨系统,必须充分重视研究对象的系统属性.本文在构建区域人口承载能力系统框架的基础上,利用主成分分析法建立综合评价模型,并对上海在不同发展阶段,与不同标准相对应的各项资源经济要素所能提供的人口承载能力进行了测算分析.     

未来30年我国粮食、淡水、能源需求的系统仿真

本文以系统动力学为主要方法,对未来我国的人口总量和经济水平进行了预测,在此基础上对未来粮食、淡水和能源的需求规模进行了仿真,提炼出人口、经济与粮食、淡水和能源需求的关联模式,并进行了灵敏度分析,探讨了为确保粮食、水、能源安全所能采取的有效措施。     

人口承载力指标系的建立及量化

有关人口承载力概念、内涵、指标体系与评价模型的研究在我国已取得了长足的发展。纵观渊源,可归结为从容量、阈值、能力等角度分别进行的研究。然而,全球经济一体化进程的不断推进,开放式条件分析框架下的人口承载力已从简单意义上的"量"演变为复杂状况下"量"与"性"才能研究的目标对象。开放式条件作为现今必需的研究背景,结合环境和资源的相对稳定性、人口规模与经济规模大小的适应性,有必要建立衡量和评价人口承载力"质量"的指标系。通过围绕社会经济状况、环境资源、区域人口状况三系统讨论了人口承载力指标系的构建与量化。     

超大城市人口—自然资源系统可持续发展水平研究——基于Laplace混合政策模拟

人口增长与集聚为超大城市的发展提供动力,也给其自然资源系统带来极大扰动,使之呈现脆弱性特征;为实现超大城市人口—自然资源可持续发展,近年来政府实施了大量调控政策,但因对城市人口—自然资源系统的复杂互动难以精确量化,导致超大城市人口与自然资源关系治理困难重重。基于此,以北京市为例构建人口—自然资源系统可持续性评价框架,从政策干预视角,分析不同类型调控政策(如人口调控、技术改进、资源管制等)与人口、自然资源的因果关系,并利用Laplace准则结合决策者风险喜好,模拟混合政策干预对人口—自然资源系统可持续性带来的影响。结果显示:政策干预是保证北京市人口—自然资源系统可持续发展的重要手段,其中,人口调控政策是北京市人口—自然资源系统可持续性变动的主要影响因素,资源管制和技术改进是次要影响因素;随着政策干预强度的增加,由于人口系统安全性和自然资源系统脆弱性的互动博弈,北京市人口—自然资源可持续性逐渐趋于稳定;在Laplace情景下,人口安全性减弱了1.82%,损失不大;而自然资源脆弱性减弱了12.13%,收益较高;最终使得人口—自然资源系统可持续性增强了6.23%。因此,对于超大城市的政策干预需...     

关于人口、资源、环境经济学的若干思考

本文通过对人口、资源、环境、经济系统框架结构的分析导出了该学科应实现的两个目标:维持系统平衡和实现系统效益最大化。围绕这两个目标讨论了该学科的研究内容,提出了应将人口、资源、环境、经济大系统建设成为灵敏的自组织系统,引入“生态人”新观念,以系统效益最大化为新的价值判断标准。     

四川省构建高效集约型人口计生信息化架构体系

始终坚持以全员人口管理为核心,构建人口计生数据资源。四川省从1997年单机版育龄妇女信息管理软件开始就把全员人口纳入计算机管理,经过10多年的不断积累,已形成了包括全年龄、全覆盖的全员人口数据库,同时通过计生业务系统的数据积累,形成了包括育龄妇女、生殖健康、独生子女、机构人事等在内的计生业务数据库,构建了较完备的人口计生数据资源。利用这些数据资源,先后为全省社会事业发展规划、人口发展战略研究、人口和计划生育条例修订、     

Impacts per unit weight in catch by two types of fisheries on a chub mackerel population

By using data on the age-specific annual fecundity and catches-at-age by each fishery in a chub mackerel (Scomber japonicus) population in the Pacific Ocean off Japan during 1970 to 1992, we evaluated the long-term fluctuation in impacts of two types of fisheries on the chub mackerel population. The purse-seine fishery consistently had a larger impact on the population than did the dip-net fishery, mainly because the catch by the former was much larger than that by the latter. To evaluate impact per unit weight in catch, we calculated the average reproductive value per unit weight over individuals caught by each fishery as an indicator of efficient use of bioresource. Because the proportion of immature fish caught by the purse-seine fishery was usually larger than that by the dip-net fishery, the impact per unit weight in catch by the purse-seine fishery was not always less than that by the dip-net fishery.     

Job Satisfaction in the Coastal Pelagic Fisheries of Senegal

The marine fishery in Senegal, West Africa, is a major source of employment and food security. It currently faces the consequences of ecological degradation. This paper examines job satisfaction among small-scale purse seine fishers, who constitute one of the dominant fishing métiers in Senegal. The research sample consists of 80 purse seine fishers in three locations along the coast with varied degrees of urbanisation. The findings suggest that purse seine fishers are generally satisfied with the extent to which the fishery meets their Social Needs and Self-Actualisation. They are dissatisfied, however, with the degree to which Basic Needs are met, with the way in which Management is carried out, and??to a lesser extent??with the condition of the natural environment. However, the study shows significant differences between the more rural and urbanised settlements. These are most pronounced with regard to the willingness to change fishing type, move to another profession or advise a young person to enter fishing.     

Above and Below the Water: Social/Ecological Transformation in Northwest Newfoundland

Marine fisheries and fishing societies develop around the resources provided by a particular ecosystem. As they exploit these resources, fisheries transform the ecosystem, which pushes fishery and society to adapt in turn. This process is illustrated by fisheries, ecological and social data tracking dramatic changes on Newfoundland's Northern Peninsula and its adjacent marine ecosystem, the northern Gulf of St. Lawrence. There a longstanding fishery for cod and other groundfish collapsed in the 1990s, and was replaced by fisheries targeting invertebrates. The new invertebrate fisheries have different socioeconomic characteristics than the former groundfish fisheries. The shift in target species reflects deep ecological changes that were underway at least a decade before official recognition of the crisis. Our analysis of biological data reveals that the main ecological changes occurred during the glory years of the 1980s, when Newfoundland's domestic fisheries were at their peak. Overfishing and interactions with adverse climatic conditions drove the changes. As the ecosystem transformed, human population declined due to outmigration, and social indicators show signs of distress. Accounts by outport residents paint a generational picture of social change.     

Above and Below the Water: Social/Ecological Transformation in Northwest Newfoundland

Marine fisheries and fishing societies develop around the resources provided by a particular ecosystem. As they exploit these resources, fisheries transform the ecosystem, which pushes fishery and society to adapt in turn. This process is illustrated by fisheries, ecological and social data tracking dramatic changes on Newfoundland's Northern Peninsula and its adjacent marine ecosystem, the northern Gulf of St. Lawrence. There a longstanding fishery for cod and other groundfish collapsed in the 1990s, and was replaced by fisheries targeting invertebrates. The new invertebrate fisheries have different socioeconomic characteristics than the former groundfish fisheries. The shift in target species reflects deep ecological changes that were underway at least a decade before official recognition of the crisis. Our analysis of biological data reveals that the main ecological changes occurred during the glory years of the 1980s, when Newfoundland's domestic fisheries were at their peak. Overfishing and interactions with adverse climatic conditions drove the changes. As the ecosystem transformed, human population declined due to outmigration, and social indicators show signs of distress. Accounts by outport residents paint a generational picture of social change.     

我国独生子女规模估计及其生育政策调整对未来人口控制的影响

本文对目前人们关心的有关独生子女的生育政策是否应该调整、调整生育政策会对我国人口发展产生那些影响等问题进行探讨.为了实现这一目的,本文首先给出我国城镇人口中独生子女的规模和年龄分布估计的方法和模型,然后,利用得到的估计值对不同的独生子女生育政策进行队列模拟,通过比较得出结论.     

顺德市人口、资源、环境与可持续发展

本文模拟了顺德市在不实行计划生育政策的条件下的人口增长情况 ,结果发现由于计划生育 ,在 1971- 1998年间 ,顺德市少生了 5 0多万人口 ,从而使顺德市的人口、资源、环境在经济高速发展的情况下仍能基本协调。文章也分析了顺德市目前的人口、资源与环境可持续发展的状况和问题 ,并提出了一些建议     

Simulation of movement and egglaying inDanaus plexippus (Lepidoptera: Nymphalidae)

Summary A model simulating the movement and oviposition of monarch butterflies over a female's life time is presented. The model's predictions compare favourably with observed data and suggest that females who lay eggs in an optimal fashion should have low directionalities in areas with high host plant density (patches and single plants) and high directionalities in areas with low host plant density. The model also provides one means of combining individual animal processes and spatial heterogeneity into population dynamics.